The physiologically active form of vitamin D. It is formed primarily in the kidney by enzymatic hydroxylation of 25-hydroxycholecalciferol (CALCIFEDIOL). Its production is stimulated by low blood calcium levels and parathyroid hormone. Calcitriol increases intestinal absorption of calcium and phosphorus, and in concert with parathyroid hormone increases bone resorption.
A physiologically active metabolite of VITAMIN D. The compound is involved in the regulation of calcium metabolism, alkaline phosphatase activity, and enhances the calcemic effect of CALCITRIOL.
Proteins, usually found in the cytoplasm, that specifically bind calcitriol, migrate to the nucleus, and regulate transcription of specific segments of DNA with the participation of D receptor interacting proteins (called DRIP). Vitamin D is converted in the liver and kidney to calcitriol and ultimately acts through these receptors.
Cholecalciferols substituted with two hydroxy groups in any position.
Hydroxy analogs of vitamin D 3; (CHOLECALCIFEROL); including CALCIFEDIOL; CALCITRIOL; and 24,25-DIHYDROXYVITAMIN D 3.
The major circulating metabolite of VITAMIN D3. It is produced in the LIVER and is the best indicator of the body's vitamin D stores. It is effective in the treatment of RICKETS and OSTEOMALACIA, both in azotemic and non-azotemic patients. Calcifediol also has mineralizing properties.
A vitamin that includes both CHOLECALCIFEROLS and ERGOCALCIFEROLS, which have the common effect of preventing or curing RICKETS in animals. It can also be viewed as a hormone since it can be formed in SKIN by action of ULTRAVIOLET RAYS upon the precursors, 7-dehydrocholesterol and ERGOSTEROL, and acts on VITAMIN D RECEPTORS to regulate CALCIUM in opposition to PARATHYROID HORMONE.
Derivative of 7-dehydroxycholesterol formed by ULTRAVIOLET RAYS breaking of the C9-C10 bond. It differs from ERGOCALCIFEROL in having a single bond between C22 and C23 and lacking a methyl group at C24.
A mitochondrial cytochrome P450 enzyme that catalyzes the 1-alpha-hydroxylation of 25-hydroxyvitamin D3 (also known as 25-hydroxycholecalciferol) in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP27B1 gene, converts 25-hydroxyvitamin D3 to 1-alpha,25-dihydroxyvitamin D3 which is the active form of VITAMIN D in regulating bone growth and calcium metabolism. This enzyme is also active on plant 25-hydroxyvitamin D2 (ergocalciferol).
Cytochrome P-450 monooxygenases (MIXED FUNCTION OXYGENASES) that are important in steroid biosynthesis and metabolism.
Derivatives of ERGOSTEROL formed by ULTRAVIOLET RAYS breaking of the C9-C10 bond. They differ from CHOLECALCIFEROL in having a double bond between C22 and C23 and a methyl group at C24.
Proteins found usually in the cytoplasm or nucleus that specifically bind steroid hormones and trigger changes influencing the behavior of cells. The steroid receptor-steroid hormone complex regulates the transcription of specific genes.
A DNA sequence that is found in the promoter region of vitamin D regulated genes. Vitamin D receptor (RECEPTOR, CALCITRIOL) binds to and regulates the activity of genes containing this element.
A polypeptide hormone (84 amino acid residues) secreted by the PARATHYROID GLANDS which performs the essential role of maintaining intracellular CALCIUM levels in the body. Parathyroid hormone increases intracellular calcium by promoting the release of CALCIUM from BONE, increases the intestinal absorption of calcium, increases the renal tubular reabsorption of calcium, and increases the renal excretion of phosphates.
A nutritional condition produced by a deficiency of VITAMIN D in the diet, insufficient production of vitamin D in the skin, inadequate absorption of vitamin D from the diet, or abnormal conversion of vitamin D to its bioactive metabolites. It is manifested clinically as RICKETS in children and OSTEOMALACIA in adults. (From Cecil Textbook of Medicine, 19th ed, p1406)
Disorders caused by interruption of BONE MINERALIZATION manifesting as OSTEOMALACIA in adults and characteristic deformities in infancy and childhood due to disturbances in normal BONE FORMATION. The mineralization process may be interrupted by disruption of VITAMIN D; PHOSPHORUS; or CALCIUM homeostasis, resulting from dietary deficiencies, or acquired, or inherited metabolic, or hormonal disturbances.
An alpha-globulin found in the plasma of man and other vertebrates. It is apparently synthesized in the liver and carries vitamin D and its metabolites through the circulation and mediates the response of tissue. It is also known as group-specific component (Gc). Gc subtypes are used to determine specific phenotypes and gene frequencies. These data are employed in the classification of population groups, paternity investigations, and in forensic medicine.
An inherited condition of abnormally low serum levels of PHOSPHATES (below 1 mg/liter) which can occur in a number of genetic diseases with defective reabsorption of inorganic phosphorus by the PROXIMAL RENAL TUBULES. This leads to phosphaturia, HYPOPHOSPHATEMIA, and disturbances of cellular and organ functions such as those in X-LINKED HYPOPHOSPHATEMIC RICKETS; OSTEOMALACIA; and FANCONI SYNDROME.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
A calbindin protein found in many mammalian tissues, including the UTERUS, PLACENTA, BONE, PITUITARY GLAND, and KIDNEYS. In intestinal ENTEROCYTES it mediates intracellular calcium transport from apical to basolateral membranes via calcium binding at two EF-HAND MOTIFS. Expression is regulated in some tissues by VITAMIN D.
A non-metal element that has the atomic symbol P, atomic number 15, and atomic weight 31. It is an essential element that takes part in a broad variety of biochemical reactions.
A promyelocytic cell line derived from a patient with ACUTE PROMYELOCYTIC LEUKEMIA. HL-60 cells lack specific markers for LYMPHOID CELLS but express surface receptors for FC FRAGMENTS and COMPLEMENT SYSTEM PROTEINS. They also exhibit phagocytic activity and responsiveness to chemotactic stimuli. (From Hay et al., American Type Culture Collection, 7th ed, pp127-8)
Calcium-binding proteins that are found in DISTAL KIDNEY TUBULES, INTESTINES, BRAIN, and other tissues where they bind, buffer and transport cytoplasmic calcium. Calbindins possess a variable number of EF-HAND MOTIFS which contain calcium-binding sites. Some isoforms are regulated by VITAMIN D.
Agents that increase calcium influx into calcium channels of excitable tissues. This causes vasoconstriction in VASCULAR SMOOTH MUSCLE and/or CARDIAC MUSCLE cells as well as stimulation of insulin release from pancreatic islets. Therefore, tissue-selective calcium agonists have the potential to combat cardiac failure and endocrinological disorders. They have been used primarily in experimental studies in cell and tissue culture.
Vitamin K-dependent calcium-binding protein synthesized by OSTEOBLASTS and found primarily in BONES. Serum osteocalcin measurements provide a noninvasive specific marker of bone metabolism. The protein contains three residues of the amino acid gamma-carboxyglutamic acid (Gla), which, in the presence of CALCIUM, promotes binding to HYDROXYAPATITE and subsequent accumulation in BONE MATRIX.
A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.
Abnormally high level of calcium in the blood.
Disorder caused by an interruption of the mineralization of organic bone matrix leading to bone softening, bone pain, and weakness. It is the adult form of rickets resulting from disruption of VITAMIN D; PHOSPHORUS; or CALCIUM homeostasis.
9,10-Secoergosta-5,7,10(19),22-tetraene-3,25-diol. Biologically active metabolite of vitamin D2 which is more active in curing rickets than its parent. The compound is believed to attach to the same receptor as vitamin D2 and 25-hydroxyvitamin D3.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
Organic substances that are required in small amounts for maintenance and growth, but which cannot be manufactured by the human body.
A subtype of RETINOIC ACID RECEPTORS that are specific for 9-cis-retinoic acid which function as nuclear TRANSCRIPTION FACTORS that regulate multiple signaling pathways.
Inorganic salts of phosphoric acid.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
An NAPH-dependent cytochrome P450 enzyme that catalyzes the oxidation of the side chain of sterol intermediates such as the 27-hydroxylation of 5-beta-cholestane-3-alpha,7-alpha,12-alpha-triol.
Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.
The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.
Bone-forming cells which secrete an EXTRACELLULAR MATRIX. HYDROXYAPATITE crystals are then deposited into the matrix to form bone.
The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.
Steroids in which fission of one or more ring structures and concomitant addition of a hydrogen atom at each terminal group has occurred.
A sarcoma originating in bone-forming cells, affecting the ends of long bones. It is the most common and most malignant of sarcomas of the bones, and occurs chiefly among 10- to 25-year-old youths. (From Stedman, 25th ed)
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
Established cell cultures that have the potential to propagate indefinitely.
A condition of an abnormally low level of PHOSPHATES in the blood.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Calcium compounds used as food supplements or in food to supply the body with calcium. Dietary calcium is needed during growth for bone development and for maintenance of skeletal integrity later in life to prevent osteoporosis.
Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.
The rate dynamics in chemical or physical systems.
Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.
Two pairs of small oval-shaped glands located in the front and the base of the NECK and adjacent to the two lobes of THYROID GLAND. They secrete PARATHYROID HORMONE that regulates the balance of CALCIUM; PHOSPHORUS; and MAGNESIUM in the body.
The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.
A calcium-binding protein that mediates calcium HOMEOSTASIS in KIDNEYS, BRAIN, and other tissues. It is found in well-defined populations of NEURONS and is involved in CALCIUM SIGNALING and NEURONAL PLASTICITY. It is regulated in some tissues by VITAMIN D.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A VITAMIN D that can be regarded as a reduction product of vitamin D2.
A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.
Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.
An important regulator of GENE EXPRESSION during growth and development, and in NEOPLASMS. Tretinoin, also known as retinoic acid and derived from maternal VITAMIN A, is essential for normal GROWTH; and EMBRYONIC DEVELOPMENT. An excess of tretinoin can be teratogenic. It is used in the treatment of PSORIASIS; ACNE VULGARIS; and several other SKIN DISEASES. It has also been approved for use in promyelocytic leukemia (LEUKEMIA, PROMYELOCYTIC, ACUTE).
An acute myeloid leukemia in which abnormal PROMYELOCYTES predominate. It is frequently associated with DISSEMINATED INTRAVASCULAR COAGULATION.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.
A hereditary disorder characterized by HYPOPHOSPHATEMIA; RICKETS; OSTEOMALACIA; renal defects in phosphate reabsorption and vitamin D metabolism; and growth retardation. Autosomal and X-linked dominant and recessive variants have been reported.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.1.
Proteins in the nucleus or cytoplasm that specifically bind RETINOIC ACID or RETINOL and trigger changes in the behavior of cells. Retinoic acid receptors, like steroid receptors, are ligand-activated transcription regulators. Several types have been recognized.
Uptake of substances through the lining of the INTESTINES.
A peptide hormone that lowers calcium concentration in the blood. In humans, it is released by thyroid cells and acts to decrease the formation and absorptive activity of osteoclasts. Its role in regulating plasma calcium is much greater in children and in certain diseases than in normal adults.
A family of small polypeptide growth factors that share several common features including a strong affinity for HEPARIN, and a central barrel-shaped core region of 140 amino acids that is highly homologous between family members. Although originally studied as proteins that stimulate the growth of fibroblasts this distinction is no longer a requirement for membership in the fibroblast growth factor family.
Reduction of the blood calcium below normal. Manifestations include hyperactive deep tendon reflexes, Chvostek's sign, muscle and abdominal cramps, and carpopedal spasm. (Dorland, 27th ed)
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
The action of a drug in promoting or enhancing the effectiveness of another drug.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
A large multinuclear cell associated with the BONE RESORPTION. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in CEMENTUM resorption.
Bone loss due to osteoclastic activity.
A condition caused by a deficiency of PARATHYROID HORMONE (or PTH). It is characterized by HYPOCALCEMIA and hyperphosphatemia. Hypocalcemia leads to TETANY. The acquired form is due to removal or injuries to the PARATHYROID GLANDS. The congenital form is due to mutations of genes, such as TBX1; (see DIGEORGE SYNDROME); CASR encoding CALCIUM-SENSING RECEPTOR; or PTH encoding parathyroid hormone.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A non-electrogenic sodium-dependent phosphate transporter. It is found primarily in apical membranes of PROXIMAL RENAL TUBULES.
A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.
Antibiotic substance isolated from streptomycin-producing strains of Streptomyces griseus. It acts by inhibiting elongation during protein synthesis.
Excretion of abnormally high level of CALCIUM in the URINE, greater than 4 mg/kg/day.
Disorders in the processing of calcium in the body: its absorption, transport, storage, and utilization.
A phorbol ester found in CROTON OIL with very effective tumor promoting activity. It stimulates the synthesis of both DNA and RNA.
An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
A ubiquitously expressed, secreted protein with bone resorption and renal calcium reabsorption activities that are similar to PARATHYROID HORMONE. It does not circulate in appreciable amounts in normal subjects, but rather exerts its biological actions locally. Overexpression of parathyroid hormone-related protein by tumor cells results in humoral calcemia of malignancy.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A mitochondrial cytochrome P450 enzyme that catalyzes the side-chain cleavage of C27 cholesterol to C21 pregnenolone in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP11A1 gene, catalyzes the breakage between C20 and C22 which is the initial and rate-limiting step in the biosynthesis of various gonadal and adrenal steroid hormones.
A polypeptide that consists of the 1-34 amino-acid fragment of human PARATHYROID HORMONE, the biologically active N-terminal region. The acetate form is given by intravenous infusion in the differential diagnosis of HYPOPARATHYROIDISM and PSEUDOHYPOPARATHYROIDISM. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1995)
Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)
Elements of limited time intervals, contributing to particular results or situations.
A compound composed of a two CYCLIC PEPTIDES attached to a phenoxazine that is derived from STREPTOMYCES parvullus. It binds to DNA and inhibits RNA synthesis (transcription), with chain elongation more sensitive than initiation, termination, or release. As a result of impaired mRNA production, protein synthesis also declines after dactinomycin therapy. (From AMA Drug Evaluations Annual, 1993, p2015)
A membrane-bound metalloendopeptidase that may play a role in the degradation or activation of a variety of PEPTIDE HORMONES and INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS. Genetic mutations that result in loss of function of this protein are a cause of HYPOPHOSPHATEMIC RICKETS, X-LINKED DOMINANT.
A cell line derived from cultured tumor cells.
Human colonic ADENOCARCINOMA cells that are able to express differentiation features characteristic of mature intestinal cells, such as ENTEROCYTES. These cells are valuable in vitro tools for studies related to intestinal cell function and differentiation.
An anti-inflammatory 9-fluoro-glucocorticoid.
Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.
Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.
A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.
A group of DITERPENES cyclized into 3-ring PHENANTHRENES.
Abnormally elevated PARATHYROID HORMONE secretion as a response to HYPOCALCEMIA. It is caused by chronic KIDNEY FAILURE or other abnormalities in the controls of bone and mineral metabolism, leading to various BONE DISEASES, such as RENAL OSTEODYSTROPHY.
A subgroup of TRP cation channels named after vanilloid receptor. They are very sensitive to TEMPERATURE and hot spicy food and CAPSAICIN. They have the TRP domain and ANKYRIN repeats. Selectivity for CALCIUM over SODIUM ranges from 3 to 100 fold.
The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.
Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.
Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)
Glucuronidase is an enzyme (specifically, a glycosidase) that catalyzes the hydrolysis of glucuronic acid from various substrates, playing crucial roles in metabolic processes like detoxification and biotransformation within organisms.
A human cell line established from a diffuse histiocytic lymphoma (HISTIOCYTIC LYMPHOMA, DIFFUSE) and displaying many monocytic characteristics. It serves as an in vitro model for MONOCYTE and MACROPHAGE differentiation.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Nucleotide sequences, usually upstream, which are recognized by specific regulatory transcription factors, thereby causing gene response to various regulatory agents. These elements may be found in both promoter and enhancer regions.
A negatively-charged extracellular matrix protein that plays a role in the regulation of BONE metabolism and a variety of other biological functions. Cell signaling by osteopontin may occur through a cell adhesion sequence that recognizes INTEGRIN ALPHA-V BETA-3.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
A bile acid formed from chenodeoxycholate by bacterial action, usually conjugated with glycine or taurine. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as cholagogue and choleretic.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
All of the processes involved in increasing CELL NUMBER including CELL DIVISION.
Glycoproteins which contain sialic acid as one of their carbohydrates. They are often found on or in the cell or tissue membranes and participate in a variety of biological activities.
Tumors or cancer of the PROSTATE.
Clonal expansion of myeloid blasts in bone marrow, blood, and other tissue. Myeloid leukemias develop from changes in cells that normally produce NEUTROPHILS; BASOPHILS; EOSINOPHILS; and MONOCYTES.
The growth and development of bones from fetus to adult. It includes two principal mechanisms of bone growth: growth in length of long bones at the epiphyseal cartilages and growth in thickness by depositing new bone (OSTEOGENESIS) with the actions of OSTEOBLASTS and OSTEOCLASTS.
The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)
A transmembrane protein belonging to the tumor necrosis factor superfamily that specifically binds RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B and OSTEOPROTEGERIN. It plays an important role in regulating OSTEOCLAST differentiation and activation.
Excision of kidney.
An idiopathic systemic inflammatory granulomatous disorder comprised of epithelioid and multinucleated giant cells with little necrosis. It usually invades the lungs with fibrosis and may also involve lymph nodes, skin, liver, spleen, eyes, phalangeal bones, and parotid glands.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.
An electrogenic sodium-dependent phosphate transporter. It is present primarily in BRUSH BORDER membranes of PROXIMAL RENAL TUBULES.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
Form of leukemia characterized by an uncontrolled proliferation of the myeloid lineage and their precursors (MYELOID PROGENITOR CELLS) in the bone marrow and other sites.
Phosphorus used in foods or obtained from food. This element is a major intracellular component which plays an important role in many biochemical pathways relating to normal physiological functions. High concentrations of dietary phosphorus can cause nephrocalcinosis which is associated with impaired kidney function. Low concentrations of dietary phosphorus cause an increase in calcitriol in the blood and osteoporosis.
Chemical substances having a specific regulatory effect on the activity of a certain organ or organs. The term was originally applied to substances secreted by various ENDOCRINE GLANDS and transported in the bloodstream to the target organs. It is sometimes extended to include those substances that are not produced by the endocrine glands but that have similar effects.
A highly polar organic liquid, that is used widely as a chemical solvent. Because of its ability to penetrate biological membranes, it is used as a vehicle for topical application of pharmaceuticals. It is also used to protect tissue during CRYOPRESERVATION. Dimethyl sulfoxide shows a range of pharmacological activity including analgesia and anti-inflammation.
The processes whereby the internal environment of an organism tends to remain balanced and stable.
A mediator complex subunit that is believed to play a key role in the coactivation of nuclear receptor-activated transcription by the mediator complex. It interacts with a variety of nuclear receptors including RETINOIC ACID RECEPTORS; THYROID HORMONE RECEPTORS; VITAMIN D RECEPTORS; PEROXISOME PROLIFERATOR-ACTIVATED RECEPTORS; ESTROGEN RECEPTORS; and GLUCOCORTICOID RECEPTORS.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A disease of pregnant and lactating cows and ewes leading to generalized paresis and death. The disease, which is characterized by hypocalcemia, occurs at or shortly after parturition in cows and within weeks before or after parturition in ewes.
Substances that inhibit or prevent the proliferation of NEOPLASMS.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Endogenous or exogenous substances which inhibit the normal growth of human and animal cells or micro-organisms, as distinguished from those affecting plant growth (= PLANT GROWTH REGULATORS).
A cyclin subtype that binds to the CYCLIN-DEPENDENT KINASE 3 and CYCLIN-DEPENDENT KINASE 8. Cyclin C plays a dual role as a transcriptional regulator and a G1 phase CELL CYCLE regulator.
A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Native, inorganic or fossilized organic substances having a definite chemical composition and formed by inorganic reactions. They may occur as individual crystals or may be disseminated in some other mineral or rock. (Grant & Hackh's Chemical Dictionary, 5th ed; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Anthelmintic isolated from the dried unexpanded flower heads of Artemisia maritima and other species of Artemisia found principally in Russian and Chinese Turkestan and the Southern Ural region. (From Merck, 11th ed.)
A hereditary syndrome clinically similar to HYPOPARATHYROIDISM. It is characterized by HYPOCALCEMIA; HYPERPHOSPHATEMIA; and associated skeletal development impairment and caused by failure of response to PARATHYROID HORMONE rather than deficiencies. A severe form with resistance to multiple hormones is referred to as Type 1a and is associated with maternal mutant allele of the ALPHA CHAIN OF STIMULATORY G PROTEIN.
Disorders in the processing of phosphorus in the body: its absorption, transport, storage, and utilization.
A secreted member of the TNF receptor superfamily that negatively regulates osteoclastogenesis. It is a soluble decoy receptor of RANK LIGAND that inhibits both CELL DIFFERENTIATION and function of OSTEOCLASTS by inhibiting the interaction between RANK LIGAND and RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B.
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.
Absence of hair from areas where it is normally present.
Cholesterol derivatives having an additional double bond in any position. 24-Dehydrocholesterol is DESMOSTEROL. The other most prevalent dehydrocholesterol is the 7-isomer. This compound is a precursor of cholesterol and of vitamin D3.
A mixed mesenchymal tumor composed of two or more mesodermal cellular elements not commonly associated, not counting fibrous tissue as one of the elements. Mesenchymomas are widely distributed in the body and about 75% are malignant. (Dorland, 27th ed; Holland et al., Cancer Medicine, 3d ed, p1866)
The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.
A glycoprotein component of HIGH-DENSITY LIPOPROTEINS that transports small hydrophobic ligands including CHOLESTEROL and STEROLS. It occurs in the macromolecular complex with LECITHIN CHOLESTEROL ACYLTRANSFERASE. Apo D is expressed in and secreted from a variety of tissues such as liver, placenta, brain tissue and others.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in neoplastic tissue.
Glycolipid-anchored membrane glycoproteins expressed on cells of the myelomonocyte lineage including monocytes, macrophages, and some granulocytes. They function as receptors for the complex of lipopolysaccharide (LPS) and LPS-binding protein.
A tumor necrosis factor receptor family member that is specific for RANK LIGAND and plays a role in bone homeostasis by regulating osteoclastogenesis. It is also expressed on DENDRITIC CELLS where it plays a role in regulating dendritic cell survival. Signaling by the activated receptor occurs through its association with TNF RECEPTOR-ASSOCIATED FACTORS.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
A condition of abnormally elevated output of PARATHYROID HORMONE (or PTH) triggering responses that increase blood CALCIUM. It is characterized by HYPERCALCEMIA and BONE RESORPTION, eventually leading to bone diseases. PRIMARY HYPERPARATHYROIDISM is caused by parathyroid HYPERPLASIA or PARATHYROID NEOPLASMS. SECONDARY HYPERPARATHYROIDISM is increased PTH secretion in response to HYPOCALCEMIA, usually caused by chronic KIDNEY DISEASES.
The 17-valerate derivative of BETAMETHASONE. It has substantial topical anti-inflammatory activity and relatively low systemic anti-inflammatory activity.
A class of G-protein-coupled receptors that react to varying extracellular CALCIUM levels. Calcium-sensing receptors in the PARATHYROID GLANDS play an important role in the maintenance of calcium HOMEOSTASIS by regulating the release of PARATHYROID HORMONE. They differ from INTRACELLULAR CALCIUM-SENSING PROTEINS which sense intracellular calcium levels.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Tumors or cancer of the human BREAST.
Cells contained in the bone marrow including fat cells (see ADIPOCYTES); STROMAL CELLS; MEGAKARYOCYTES; and the immediate precursors of most blood cells.
A 21-amino acid peptide that circulates in the plasma, but its source is not known. Endothelin-3 has been found in high concentrations in the brain and may regulate important functions in neurons and astrocytes, such as proliferation and development. It also is found throughout the gastrointestinal tract and in the lung and kidney. (N Eng J Med 1995;333(6):356-63)
Tumors or cancer of the COLON.
One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.
The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.
Transport proteins that carry specific substances in the blood or across cell membranes.
The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).
Leukocytes with abundant granules in the cytoplasm. They are divided into three groups according to the staining properties of the granules: neutrophilic, eosinophilic, and basophilic. Mature granulocytes are the NEUTROPHILS; EOSINOPHILS; and BASOPHILS.
The physical or physiological processes by which substances, tissue, cells, etc. take up or take in other substances or energy.
Enzymes that catalyze the hydrolysis of a phenol sulfate to yield a phenol and sulfate. Arylsulfatase A, B, and C have been separated. A deficiency of arylsulfatases is one of the causes of metachromatic leukodystrophy (LEUKODYSTROPHY, METACHROMATIC). EC 3.1.6.1.
In patients with neoplastic diseases a wide variety of clinical pictures which are indirect and usually remote effects produced by tumor cell metabolites or other products.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in leukemia.
Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumor. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals.
Proteins prepared by recombinant DNA technology.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: VITAMIN K 1 (phytomenadione) derived from plants, VITAMIN K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, VITAMIN K 3 (menadione). Vitamin K 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin K. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin K.
An acute myeloid leukemia in which 80% or more of the leukemic cells are of monocytic lineage including monoblasts, promonocytes, and MONOCYTES.
An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.2.
Tritium is an isotope of hydrogen (specifically, hydrogen-3) that contains one proton and two neutrons in its nucleus, making it radioactive with a half-life of about 12.3 years, and is used in various applications including nuclear research, illumination, and dating techniques due to its low energy beta decay.
Agents that inhibit BONE RESORPTION and/or favor BONE MINERALIZATION and BONE REGENERATION. They are used to heal BONE FRACTURES and to treat METABOLIC BONE DISEASES such as OSTEOPOROSIS.
Organic silicon derivatives used to characterize hydroxysteroids, nucleosides, and related compounds. Trimethylsilyl esters of amino acids are used in peptide synthesis.
Compounds used in food or in food preparation to replace dietary fats. They may be carbohydrate-, protein-, or fat-based. Fat substitutes are usually lower in calories but provide the same texture as fats.
The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
The major interferon produced by mitogenically or antigenically stimulated LYMPHOCYTES. It is structurally different from TYPE I INTERFERON and its major activity is immunoregulation. It has been implicated in the expression of CLASS II HISTOCOMPATIBILITY ANTIGENS in cells that do not normally produce them, leading to AUTOIMMUNE DISEASES.
Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.
A method of measuring the effects of a biologically active substance using an intermediate in vivo or in vitro tissue or cell model under controlled conditions. It includes virulence studies in animal fetuses in utero, mouse convulsion bioassay of insulin, quantitation of tumor-initiator systems in mouse skin, calculation of potentiating effects of a hormonal factor in an isolated strip of contracting stomach muscle, etc.
An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.
Regular course of eating and drinking adopted by a person or animal.
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
Diseases of BONES.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
An enzyme that catalyzes the acetylation of chloramphenicol to yield chloramphenicol 3-acetate. Since chloramphenicol 3-acetate does not bind to bacterial ribosomes and is not an inhibitor of peptidyltransferase, the enzyme is responsible for the naturally occurring chloramphenicol resistance in bacteria. The enzyme, for which variants are known, is found in both gram-negative and gram-positive bacteria. EC 2.3.1.28.
Genes whose expression is easily detectable and therefore used to study promoter activity at many positions in a target genome. In recombinant DNA technology, these genes may be attached to a promoter region of interest.
Intracellular receptors that can be found in the cytoplasm or in the nucleus. They bind to extracellular signaling molecules that migrate through or are transported across the CELL MEMBRANE. Many members of this class of receptors occur in the cytoplasm and are transported to the CELL NUCLEUS upon ligand-binding where they signal via DNA-binding and transcription regulation. Also included in this category are receptors found on INTRACELLULAR MEMBRANES that act via mechanisms similar to CELL SURFACE RECEPTORS.

Calcitriol is the active form of vitamin D, also known as 1,25-dihydroxyvitamin D. It is a steroid hormone that plays a crucial role in regulating calcium and phosphate levels in the body to maintain healthy bones. Calcitriol is produced in the kidneys from its precursor, calcidiol (25-hydroxyvitamin D), which is derived from dietary sources or synthesized in the skin upon exposure to sunlight.

Calcitriol promotes calcium absorption in the intestines, helps regulate calcium and phosphate levels in the kidneys, and stimulates bone cells (osteoblasts) to form new bone tissue while inhibiting the activity of osteoclasts, which resorb bone. This hormone is essential for normal bone mineralization and growth, as well as for preventing hypocalcemia (low calcium levels).

In addition to its role in bone health, calcitriol has various other physiological functions, including modulating immune responses, cell proliferation, differentiation, and apoptosis. Calcitriol deficiency or resistance can lead to conditions such as rickets in children and osteomalacia or osteoporosis in adults.

24,25-Dihydroxyvitamin D3 is a metabolite of vitamin D3, also known as calcitriol. It is formed in the body through the hydroxylation of vitamin D3 by the enzyme 25-hydroxyvitamin D3 1-alpha-hydroxylase, which is primarily found in the kidneys.

24,25-Dihydroxyvitamin D3 plays a role in regulating calcium and phosphate metabolism, but its functions are not as well understood as those of other vitamin D metabolites. Some studies have suggested that it may have anti-inflammatory effects and may be involved in the regulation of cell growth and differentiation. However, more research is needed to fully understand the physiological role of this compound.

It's important to note that 24,25-Dihydroxyvitamin D3 is not typically used as a therapeutic agent, and its levels in the body are not routinely measured in clinical practice.

Calcitriol receptors, also known as Vitamin D receptors (VDR), are nuclear receptor proteins that bind to calcitriol (1,25-dihydroxyvitamin D3), the active form of vitamin D. These receptors are found in various tissues and cells throughout the body, including the small intestine, bone, kidney, and parathyroid gland.

When calcitriol binds to its receptor, it forms a complex that regulates the expression of genes involved in calcium and phosphate homeostasis, cell growth, differentiation, and immune function. Calcitriol receptors play a critical role in maintaining normal levels of calcium and phosphate in the blood by increasing the absorption of these minerals from the gut, promoting bone mineralization, and regulating the production of parathyroid hormone (PTH).

Calcitriol receptors have also been implicated in various disease processes, including cancer, autoimmune disorders, and infectious diseases. Modulation of calcitriol receptor activity has emerged as a potential therapeutic strategy for the treatment of these conditions.

Dihydroxycholecalciferols are a form of calcifediol, which is a type of secosteroid hormone that is produced in the body as a result of the exposure to sunlight and the dietary intake of vitamin D. The term "dihydroxycholecalciferols" specifically refers to the compounds 1,25-dihydroxycholecalciferol (calcitriol) and 24,25-dihydroxycholecalciferol. These compounds are produced in the body through a series of chemical reactions involving enzymes that convert vitamin D into its active forms.

Calcitriol is the biologically active form of vitamin D and plays an important role in regulating the levels of calcium and phosphorus in the blood, as well as promoting the absorption of these minerals from the gut. It also has other functions, such as modulating cell growth and immune function.

24,25-dihydroxycholecalciferol is a less active form of vitamin D that is produced in larger quantities than calcitriol. Its exact role in the body is not well understood, but it is thought to have some effects on calcium metabolism and may play a role in regulating the levels of other hormones in the body.

Dihydroxycholecalciferols are typically measured in the blood as part of an evaluation for vitamin D deficiency or to monitor treatment with vitamin D supplements. Low levels of these compounds can indicate a deficiency, while high levels may indicate excessive intake or impaired metabolism.

Hydroxycholecalciferols are metabolites of vitamin D that are formed in the liver and kidneys. They are important for maintaining calcium homeostasis in the body by promoting the absorption of calcium from the gut and reabsorption of calcium from the kidneys.

The two main forms of hydroxycholecalciferols are 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D). 25-hydroxyvitamin D is the major circulating form of vitamin D in the body and is used as a clinical measure of vitamin D status. It is converted to 1,25-dihydroxyvitamin D in the kidneys by the enzyme 1α-hydroxylase, which is activated in response to low serum calcium or high phosphate levels.

1,25-dihydroxyvitamin D is the biologically active form of vitamin D and plays a critical role in regulating calcium homeostasis by increasing intestinal calcium absorption and promoting bone health. Deficiency in hydroxycholecalciferols can lead to rickets in children and osteomalacia or osteoporosis in adults, characterized by weakened bones and increased risk of fractures.

Calcifediol is the medical term for 25-hydroxyvitamin D, which is a form of vitamin D that is produced in the liver when it processes vitamin D from sunlight or from dietary sources. It is an important precursor to the active form of vitamin D, calcitriol, and is often used as a supplement for people who have low levels of vitamin D. Calcifediol is converted to calcitriol in the kidneys, where it plays a role in regulating calcium and phosphate levels in the body, which are important for maintaining healthy bones and teeth.

Vitamin D is a fat-soluble secosteroid that is crucial for the regulation of calcium and phosphate levels in the body, which are essential for maintaining healthy bones and teeth. It can be synthesized by the human body when skin is exposed to ultraviolet-B (UVB) rays from sunlight, or it can be obtained through dietary sources such as fatty fish, fortified dairy products, and supplements. There are two major forms of vitamin D: vitamin D2 (ergocalciferol), which is found in some plants and fungi, and vitamin D3 (cholecalciferol), which is produced in the skin or obtained from animal-derived foods. Both forms need to undergo two hydroxylations in the body to become biologically active as calcitriol (1,25-dihydroxyvitamin D3), the hormonally active form of vitamin D. This activated form exerts its effects by binding to the vitamin D receptor (VDR) found in various tissues, including the small intestine, bone, kidney, and immune cells, thereby influencing numerous physiological processes such as calcium homeostasis, bone metabolism, cell growth, and immune function.

Cholecalciferol is the chemical name for Vitamin D3. It is a fat-soluble vitamin that is essential for the regulation of calcium and phosphate levels in the body, which helps to maintain healthy bones and teeth. Cholecalciferol can be synthesized by the skin upon exposure to sunlight or obtained through dietary sources such as fatty fish, liver, and fortified foods. It is also available as a dietary supplement.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase is an enzyme that is responsible for converting 25-hydroxyvitamin D3 (a precursor form of vitamin D) to its active form, 1,25-dihydroxyvitamin D3. This activation process occurs primarily in the kidneys and is tightly regulated by various factors such as calcium levels, parathyroid hormone, and vitamin D status.

The activated form of vitamin D, 1,25-dihydroxyvitamin D3, plays a crucial role in maintaining calcium homeostasis by increasing the absorption of calcium from the gut and promoting bone health. It also has various other functions, including modulation of immune function, cell growth regulation, and protection against cancer.

Deficiencies in 25-Hydroxyvitamin D3 1-alpha-Hydroxylase can lead to vitamin D deficiency and its associated symptoms, such as osteomalacia (softening of the bones) and osteoporosis (brittle bones). Conversely, overactivity of this enzyme can result in hypercalcemia (elevated levels of calcium in the blood), which can cause a range of symptoms including kidney stones, abdominal pain, nausea, and vomiting.

Steroid hydroxylases are enzymes that catalyze the addition of a hydroxyl group (-OH) to a steroid molecule. These enzymes are located in the endoplasmic reticulum and play a crucial role in the biosynthesis of various steroid hormones, such as cortisol, aldosterone, and sex hormones. The hydroxylation reaction catalyzed by these enzymes increases the polarity and solubility of steroids, allowing them to be further metabolized and excreted from the body.

The most well-known steroid hydroxylases are part of the cytochrome P450 family, specifically CYP11A1, CYP11B1, CYP11B2, CYP17A1, CYP19A1, and CYP21A2. Each enzyme has a specific function in steroid biosynthesis, such as converting cholesterol to pregnenolone (CYP11A1), hydroxylating the 11-beta position of steroids (CYP11B1 and CYP11B2), or performing multiple hydroxylation reactions in the synthesis of sex hormones (CYP17A1, CYP19A1, and CYP21A2).

Defects in these enzymes can lead to various genetic disorders, such as congenital adrenal hyperplasia, which is characterized by impaired steroid hormone biosynthesis.

Ergocalciferols are a form of vitamin D, specifically vitamin D2, that is found in some plants. They are not produced by the human body and must be obtained through diet or supplementation. Ergocalciferols can be converted into an active form of vitamin D in the body, which is important for maintaining healthy bones and calcium levels. However, vitamin D3 (cholecalciferol), which is produced by the body in response to sunlight exposure, is generally considered to be more effective at raising and maintaining vitamin D levels in the body than ergocalciferols.

Steroid receptors are a type of nuclear receptor protein that are activated by the binding of steroid hormones or related molecules. These receptors play crucial roles in various physiological processes, including development, homeostasis, and metabolism. Steroid receptors function as transcription factors, regulating gene expression when activated by their respective ligands.

There are several subtypes of steroid receptors, classified based on the specific steroid hormones they bind to:

1. Glucocorticoid receptor (GR): Binds to glucocorticoids, which regulate metabolism, immune response, and stress response.
2. Mineralocorticoid receptor (MR): Binds to mineralocorticoids, which regulate electrolyte and fluid balance.
3. Androgen receptor (AR): Binds to androgens, which are male sex hormones that play a role in the development and maintenance of male sexual characteristics.
4. Estrogen receptor (ER): Binds to estrogens, which are female sex hormones that play a role in the development and maintenance of female sexual characteristics.
5. Progesterone receptor (PR): Binds to progesterone, which is a female sex hormone involved in the menstrual cycle and pregnancy.
6. Vitamin D receptor (VDR): Binds to vitamin D, which plays a role in calcium homeostasis and bone metabolism.

Upon ligand binding, steroid receptors undergo conformational changes that allow them to dimerize, interact with co-regulatory proteins, and bind to specific DNA sequences called hormone response elements (HREs) in the promoter regions of target genes. This interaction leads to the recruitment of transcriptional machinery, ultimately resulting in the modulation of gene expression. Dysregulation of steroid receptor signaling has been implicated in various diseases, including cancer, metabolic disorders, and inflammatory conditions.

A Vitamin D Response Element (VDRE) is a specific sequence in the DNA to which the vitamin D receptor (VDR) binds, upon activation by its ligand, vitamin D or one of its metabolites. This binding results in the regulation of gene transcription and subsequent protein synthesis. VDREs are typically located in the promoter region of genes that are involved in calcium homeostasis, cell growth and differentiation, immune function, and other processes. The interaction between VDR and VDRE plays a crucial role in the genomic actions of vitamin D.

Parathyroid hormone (PTH) is a polypeptide hormone that plays a crucial role in the regulation of calcium and phosphate levels in the body. It is produced and secreted by the parathyroid glands, which are four small endocrine glands located on the back surface of the thyroid gland.

The primary function of PTH is to maintain normal calcium levels in the blood by increasing calcium absorption from the gut, mobilizing calcium from bones, and decreasing calcium excretion by the kidneys. PTH also increases phosphate excretion by the kidneys, which helps to lower serum phosphate levels.

In addition to its role in calcium and phosphate homeostasis, PTH has been shown to have anabolic effects on bone tissue, stimulating bone formation and preventing bone loss. However, chronic elevations in PTH levels can lead to excessive bone resorption and osteoporosis.

Overall, Parathyroid Hormone is a critical hormone that helps maintain mineral homeostasis and supports healthy bone metabolism.

Vitamin D deficiency is a condition characterized by insufficient levels of vitamin D in the body, typically defined as a serum 25-hydroxyvitamin D level below 20 nanograms per milliliter (ng/mL) or 50 nanomoles per liter (nmol/L). Vitamin D is an essential fat-soluble vitamin that plays a crucial role in maintaining healthy bones and teeth by regulating the absorption of calcium and phosphorus. It also has various other functions in the body, including modulation of cell growth, immune function, and neuromuscular activity.

Vitamin D can be obtained through dietary sources such as fatty fish, fortified dairy products, and supplements, but the majority of vitamin D is produced in the skin upon exposure to sunlight. Deficiency can occur due to inadequate dietary intake, insufficient sun exposure, or impaired absorption or metabolism of vitamin D.

Risk factors for vitamin D deficiency include older age, darker skin tone, obesity, malabsorption syndromes, liver or kidney disease, and certain medications. Symptoms of vitamin D deficiency can be subtle and nonspecific, such as fatigue, bone pain, muscle weakness, and mood changes. However, prolonged deficiency can lead to more severe health consequences, including osteoporosis, osteomalacia, and increased risk of fractures.

Rickets is a medical condition characterized by the softening and weakening of bones in children, primarily caused by deficiency of vitamin D, calcium, or phosphate. It leads to skeletal deformities, bone pain, and growth retardation. Prolonged lack of sunlight exposure, inadequate intake of vitamin D-rich foods, or impaired absorption or utilization of vitamin D can contribute to the development of rickets.

Vitamin D-Binding Protein (DBP), also known as Group-specific Component (Gc-globulin), is a protein that binds and transports vitamin D and its metabolites in the bloodstream. It plays a crucial role in maintaining the homeostasis of vitamin D by regulating the amount of free, active vitamin D available to cells. DBP also has other functions, including acting as an actin scavenger to prevent the formation of harmful actin aggregates in circulation and participating in immune responses.

Familial Hypophosphatemia is a genetic disorder characterized by low levels of phosphate in the blood (hypophosphatemia) due to impaired absorption of phosphates in the gut. This condition results from mutations in the SLC34A3 gene, which provides instructions for making a protein called NaPi-IIc, responsible for reabsorbing phosphates from the filtrate in the kidney tubules back into the bloodstream.

In familial hypophosphatemia, the impaired function of NaPi-IIc leads to excessive loss of phosphate through urine, resulting in hypophosphatemia. This condition can cause rickets (a softening and weakening of bones) in children and osteomalacia (softening of bones) in adults. Symptoms may include bowed legs, bone pain, muscle weakness, and short stature.

Familial Hypophosphatemia is inherited as an autosomal recessive trait, meaning that an individual must inherit two copies of the mutated gene (one from each parent) to develop the condition.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

S100 calcium binding protein G, also known as calgranulin A or S100A8, is a member of the S100 family of proteins. These proteins are characterized by their ability to bind calcium ions and play a role in intracellular signaling and regulation of various cellular processes.

S100 calcium binding protein G forms a heterodimer with S100 calcium binding protein B (S100A9) and is involved in the inflammatory response, immune function, and tumor growth and progression. The S100A8/A9 heterocomplex has been shown to play a role in neutrophil activation and recruitment, as well as the regulation of cytokine production and cell proliferation.

Elevated levels of S100 calcium binding protein G have been found in various inflammatory conditions, such as rheumatoid arthritis, Crohn's disease, and psoriasis, as well as in several types of cancer, including breast, lung, and colon cancer. Therefore, it has been suggested that S100 calcium binding protein G may be a useful biomarker for the diagnosis and prognosis of these conditions.

Phosphorus is an essential mineral that is required by every cell in the body for normal functioning. It is a key component of several important biomolecules, including adenosine triphosphate (ATP), which is the primary source of energy for cells, and deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), which are the genetic materials in cells.

Phosphorus is also a major constituent of bones and teeth, where it combines with calcium to provide strength and structure. In addition, phosphorus plays a critical role in various metabolic processes, including energy production, nerve impulse transmission, and pH regulation.

The medical definition of phosphorus refers to the chemical element with the atomic number 15 and the symbol P. It is a highly reactive non-metal that exists in several forms, including white phosphorus, red phosphorus, and black phosphorus. In the body, phosphorus is primarily found in the form of organic compounds, such as phospholipids, phosphoproteins, and nucleic acids.

Abnormal levels of phosphorus in the body can lead to various health problems. For example, high levels of phosphorus (hyperphosphatemia) can occur in patients with kidney disease or those who consume large amounts of phosphorus-rich foods, and can contribute to the development of calcification of soft tissues and cardiovascular disease. On the other hand, low levels of phosphorus (hypophosphatemia) can occur in patients with malnutrition, vitamin D deficiency, or alcoholism, and can lead to muscle weakness, bone pain, and an increased risk of infection.

HL-60 cells are a type of human promyelocytic leukemia cell line that is commonly used in scientific research. They are named after the hospital where they were first isolated, the Hospital of the University of Pennsylvania (HUP) and the 60th culture attempt to grow these cells.

HL-60 cells have the ability to differentiate into various types of blood cells, such as granulocytes, monocytes, and macrophages, when exposed to certain chemical compounds or under specific culturing conditions. This makes them a valuable tool for studying the mechanisms of cell differentiation, proliferation, and apoptosis (programmed cell death).

HL-60 cells are also often used in toxicity studies, drug discovery and development, and research on cancer, inflammation, and infectious diseases. They can be easily grown in the lab and have a stable genotype, making them ideal for use in standardized experiments and comparisons between different studies.

Calbindins are a family of calcium-binding proteins that are widely distributed in various tissues, including the gastrointestinal tract, brain, and kidney. They play important roles in regulating intracellular calcium levels and modulating calcium-dependent signaling pathways. Calbindin D28k, one of the major isoforms, is particularly abundant in the central nervous system and has been implicated in neuroprotection, neuronal plasticity, and regulation of neurotransmitter release. Deficiencies or alterations in calbindins have been associated with various pathological conditions, including neurological disorders and cancer.

Calcium channel agonists are substances that increase the activity or function of calcium channels. Calcium channels are specialized proteins in cell membranes that regulate the flow of calcium ions into and out of cells. They play a crucial role in various physiological processes, including muscle contraction, hormone secretion, and nerve impulse transmission.

Calcium channel agonists can enhance the opening of these channels, leading to an increased influx of calcium ions into the cells. This can result in various pharmacological effects, depending on the type of cell and tissue involved. For example, calcium channel agonists may be used to treat conditions such as hypotension (low blood pressure) or heart block by increasing cardiac contractility and heart rate. However, these agents should be used with caution due to their potential to cause adverse effects, including increased heart rate, hypertension, and arrhythmias.

Examples of calcium channel agonists include drugs such as Bay K 8644, FPL 64176, and A23187. It's important to note that some substances can act as both calcium channel agonists and antagonists, depending on the dose, concentration, or duration of exposure.

Osteocalcin is a protein that is produced by osteoblasts, which are the cells responsible for bone formation. It is one of the most abundant non-collagenous proteins found in bones and plays a crucial role in the regulation of bone metabolism. Osteocalcin contains a high affinity for calcium ions, making it essential for the mineralization of the bone matrix.

Once synthesized, osteocalcin is secreted into the extracellular matrix, where it binds to hydroxyapatite crystals, helping to regulate their growth and contributing to the overall strength and integrity of the bones. Osteocalcin also has been found to play a role in other physiological processes outside of bone metabolism, such as modulating insulin sensitivity, energy metabolism, and male fertility.

In summary, osteocalcin is a protein produced by osteoblasts that plays a critical role in bone formation, mineralization, and turnover, and has been implicated in various other physiological processes.

"Bone" is the hard, dense connective tissue that makes up the skeleton of vertebrate animals. It provides support and protection for the body's internal organs, and serves as a attachment site for muscles, tendons, and ligaments. Bone is composed of cells called osteoblasts and osteoclasts, which are responsible for bone formation and resorption, respectively, and an extracellular matrix made up of collagen fibers and mineral crystals.

Bones can be classified into two main types: compact bone and spongy bone. Compact bone is dense and hard, and makes up the outer layer of all bones and the shafts of long bones. Spongy bone is less dense and contains large spaces, and makes up the ends of long bones and the interior of flat and irregular bones.

The human body has 206 bones in total. They can be further classified into five categories based on their shape: long bones, short bones, flat bones, irregular bones, and sesamoid bones.

Hypercalcemia is a medical condition characterized by an excess of calcium ( Ca2+ ) in the blood. While the normal range for serum calcium levels is typically between 8.5 to 10.2 mg/dL (milligrams per deciliter) or 2.14 to 2.55 mmol/L (millimoles per liter), hypercalcemia is generally defined as a serum calcium level greater than 10.5 mg/dL or 2.6 mmol/L.

Hypercalcemia can result from various underlying medical disorders, including primary hyperparathyroidism, malignancy (cancer), certain medications, granulomatous diseases, and excessive vitamin D intake or production. Symptoms of hypercalcemia may include fatigue, weakness, confusion, memory loss, depression, constipation, nausea, vomiting, increased thirst, frequent urination, bone pain, and kidney stones. Severe or prolonged hypercalcemia can lead to serious complications such as kidney failure, cardiac arrhythmias, and calcification of soft tissues. Treatment depends on the underlying cause and severity of the condition.

Osteomalacia is a medical condition characterized by the softening of bones due to defective bone mineralization, resulting from inadequate vitamin D, phosphate, or calcium. It mainly affects adults and is different from rickets, which occurs in children. The primary symptom is bone pain, but muscle weakness can also occur. Prolonged osteomalacia may lead to skeletal deformities and an increased risk of fractures. Treatment typically involves supplementation with vitamin D, calcium, and sometimes phosphate.

25-Hydroxyvitamin D 2 (25(OH)D2) is a form of vitamin D that is produced in the body as a result of the metabolism of ergocalciferol, also known as vitamin D2. Vitamin D2 is found in some plant-based foods and is sometimes used as a dietary supplement.

When vitamin D2 is ingested or absorbed through the skin after exposure to sunlight, it is converted in the liver to 25(OH)D2. This form of vitamin D is then further metabolized in the kidneys to the active form of vitamin D, calcitriol (1,25-dihydroxyvitamin D).

Like other forms of vitamin D, 25(OH)D2 is important for maintaining healthy bones and muscles by regulating the absorption of calcium and phosphorus from the diet. It may also have other health benefits, such as reducing the risk of certain cancers and autoimmune disorders.

It's worth noting that 25-Hydroxyvitamin D2 is not usually measured in clinical settings, as it is converted to 25-Hydroxyvitamin D3 (25(OH)D3) in the body, and total 25(OH)D (which includes both 25(OH)D2 and 25(OH)D3) is typically measured to assess vitamin D status.

Cell differentiation is the process by which a less specialized cell, or stem cell, becomes a more specialized cell type with specific functions and structures. This process involves changes in gene expression, which are regulated by various intracellular signaling pathways and transcription factors. Differentiation results in the development of distinct cell types that make up tissues and organs in multicellular organisms. It is a crucial aspect of embryonic development, tissue repair, and maintenance of homeostasis in the body.

Vitamins are organic substances that are essential in small quantities for the normal growth, development, and maintenance of life in humans. They are required for various biochemical functions in the body such as energy production, blood clotting, immune function, and making DNA.

Unlike macronutrients (carbohydrates, proteins, and fats), vitamins do not provide energy but they play a crucial role in energy metabolism. Humans require 13 essential vitamins, which can be divided into two categories: fat-soluble and water-soluble.

Fat-soluble vitamins (A, D, E, and K) are stored in the body's fat tissues and liver, and can stay in the body for a longer period of time. Water-soluble vitamins (B-complex vitamins and vitamin C) are not stored in the body and need to be replenished regularly through diet or supplementation.

Deficiency of vitamins can lead to various health problems, while excessive intake of certain fat-soluble vitamins can also be harmful due to toxicity. Therefore, it is important to maintain a balanced diet that provides all the essential vitamins in adequate amounts.

Retinoid X receptors (RXRs) are a subfamily of nuclear receptor proteins that function as transcription factors, playing crucial roles in the regulation of gene expression. They are activated by binding to retinoids, which are derivatives of vitamin A. RXRs can form heterodimers with other nuclear receptors, such as peroxisome proliferator-activated receptors (PPARs), liver X receptors (LXRs), farnesoid X receptors (FXRs), and thyroid hormone receptors (THRs). Upon activation by their respective ligands, these heterodimers bind to specific DNA sequences called response elements in the promoter regions of target genes, leading to modulation of transcription. RXRs are involved in various biological processes, including cell differentiation, development, metabolism, and homeostasis. Dysregulation of RXR-mediated signaling pathways has been implicated in several diseases, such as cancer, diabetes, and inflammatory disorders.

Phosphates, in a medical context, refer to the salts or esters of phosphoric acid. Phosphates play crucial roles in various biological processes within the human body. They are essential components of bones and teeth, where they combine with calcium to form hydroxyapatite crystals. Phosphates also participate in energy transfer reactions as phosphate groups attached to adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Additionally, they contribute to buffer systems that help maintain normal pH levels in the body.

Abnormal levels of phosphates in the blood can indicate certain medical conditions. High phosphate levels (hyperphosphatemia) may be associated with kidney dysfunction, hyperparathyroidism, or excessive intake of phosphate-containing products. Low phosphate levels (hypophosphatemia) might result from malnutrition, vitamin D deficiency, or certain diseases affecting the small intestine or kidneys. Both hypophosphatemia and hyperphosphatemia can have significant impacts on various organ systems and may require medical intervention.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Cholestanetriol 26-monooxygenase is an enzyme that is involved in the metabolism of bile acids and steroids in the body. This enzyme is responsible for adding a hydroxyl group (-OH) to the cholestanetriol molecule at position 26, which is a critical step in the conversion of cholestanetriol to bile acids.

The gene that encodes this enzyme is called CYP3A4, which is located on chromosome 7 in humans. Mutations in this gene can lead to various metabolic disorders, including impaired bile acid synthesis and altered steroid hormone metabolism.

Deficiency or dysfunction of cholestanetriol 26-monooxygenase has been associated with several diseases, such as liver disease, cerebrotendinous xanthomatosis, and some forms of cancer. Therefore, understanding the function and regulation of this enzyme is essential for developing new therapies and treatments for these conditions.

"Chickens" is a common term used to refer to the domesticated bird, Gallus gallus domesticus, which is widely raised for its eggs and meat. However, in medical terms, "chickens" is not a standard term with a specific definition. If you have any specific medical concern or question related to chickens, such as food safety or allergies, please provide more details so I can give a more accurate answer.

The duodenum is the first part of the small intestine, immediately following the stomach. It is a C-shaped structure that is about 10-12 inches long and is responsible for continuing the digestion process that begins in the stomach. The duodenum receives partially digested food from the stomach through the pyloric valve and mixes it with digestive enzymes and bile produced by the pancreas and liver, respectively. These enzymes help break down proteins, fats, and carbohydrates into smaller molecules, allowing for efficient absorption in the remaining sections of the small intestine.

Osteoblasts are specialized bone-forming cells that are derived from mesenchymal stem cells. They play a crucial role in the process of bone formation and remodeling. Osteoblasts synthesize, secrete, and mineralize the organic matrix of bones, which is mainly composed of type I collagen.

These cells have receptors for various hormones and growth factors that regulate their activity, such as parathyroid hormone, vitamin D, and transforming growth factor-beta. When osteoblasts are not actively producing bone matrix, they can become trapped within the matrix they produce, where they differentiate into osteocytes, which are mature bone cells that play a role in maintaining bone structure and responding to mechanical stress.

Abnormalities in osteoblast function can lead to various bone diseases, such as osteoporosis, osteogenesis imperfecta, and Paget's disease of bone.

The intestines, also known as the bowel, are a part of the digestive system that extends from the stomach to the anus. They are responsible for the further breakdown and absorption of nutrients from food, as well as the elimination of waste products. The intestines can be divided into two main sections: the small intestine and the large intestine.

The small intestine is a long, coiled tube that measures about 20 feet in length and is lined with tiny finger-like projections called villi, which increase its surface area and enhance nutrient absorption. The small intestine is where most of the digestion and absorption of nutrients takes place.

The large intestine, also known as the colon, is a wider tube that measures about 5 feet in length and is responsible for absorbing water and electrolytes from digested food, forming stool, and eliminating waste products from the body. The large intestine includes several regions, including the cecum, colon, rectum, and anus.

Together, the intestines play a critical role in maintaining overall health and well-being by ensuring that the body receives the nutrients it needs to function properly.

Secosteroids are a type of steroid molecule that contains a broken bond in the steroid ring structure. The term "secosteroid" is derived from "secosecondary alcohol," which refers to the hydroxyl group (-OH) that is formed when the bond is broken.

The most well-known example of a secosteroid is vitamin D, which is actually a family of related compounds known as calciferols. In vitamin D, the bond between carbons 9 and 10 in the steroid ring structure is broken, forming a new polar group that allows the molecule to act as a hormone.

Secosteroids have a variety of biological activities, including roles in calcium metabolism, immune function, and cell growth and differentiation. In addition to vitamin D, other examples of secosteroids include certain forms of bile acids and steroid hormones that are produced by the body in response to stress or injury.

Osteosarcoma is defined as a type of cancerous tumor that arises from the cells that form bones (osteoblasts). It's the most common primary bone cancer, and it typically develops in the long bones of the body, such as the arms or legs, near the growth plates. Osteosarcoma can metastasize (spread) to other parts of the body, including the lungs, making it a highly malignant form of cancer. Symptoms may include bone pain, swelling, and fractures. Treatment usually involves a combination of surgery, chemotherapy, and/or radiation therapy.

A kidney, in medical terms, is one of two bean-shaped organs located in the lower back region of the body. They are essential for maintaining homeostasis within the body by performing several crucial functions such as:

1. Regulation of water and electrolyte balance: Kidneys help regulate the amount of water and various electrolytes like sodium, potassium, and calcium in the bloodstream to maintain a stable internal environment.

2. Excretion of waste products: They filter waste products from the blood, including urea (a byproduct of protein metabolism), creatinine (a breakdown product of muscle tissue), and other harmful substances that result from normal cellular functions or external sources like medications and toxins.

3. Endocrine function: Kidneys produce several hormones with important roles in the body, such as erythropoietin (stimulates red blood cell production), renin (regulates blood pressure), and calcitriol (activated form of vitamin D that helps regulate calcium homeostasis).

4. pH balance regulation: Kidneys maintain the proper acid-base balance in the body by excreting either hydrogen ions or bicarbonate ions, depending on whether the blood is too acidic or too alkaline.

5. Blood pressure control: The kidneys play a significant role in regulating blood pressure through the renin-angiotensin-aldosterone system (RAAS), which constricts blood vessels and promotes sodium and water retention to increase blood volume and, consequently, blood pressure.

Anatomically, each kidney is approximately 10-12 cm long, 5-7 cm wide, and 3 cm thick, with a weight of about 120-170 grams. They are surrounded by a protective layer of fat and connected to the urinary system through the renal pelvis, ureters, bladder, and urethra.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Hypophosphatemia is a medical condition characterized by abnormally low levels of phosphate (phosphorus) in the blood, specifically below 2.5 mg/dL. Phosphate is an essential electrolyte that plays a crucial role in various bodily functions such as energy production, bone formation, and maintaining acid-base balance.

Hypophosphatemia can result from several factors, including malnutrition, vitamin D deficiency, alcoholism, hormonal imbalances, and certain medications. Symptoms of hypophosphatemia may include muscle weakness, fatigue, bone pain, confusion, and respiratory failure in severe cases. Treatment typically involves correcting the underlying cause and administering phosphate supplements to restore normal levels.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Dietary calcium is a type of calcium that is obtained through food sources. Calcium is an essential mineral that is necessary for many bodily functions, including bone formation and maintenance, muscle contraction, nerve impulse transmission, and blood clotting.

The recommended daily intake of dietary calcium varies depending on age, sex, and other factors. For example, the recommended daily intake for adults aged 19-50 is 1000 mg, while women over 50 and men over 70 require 1200 mg per day.

Good dietary sources of calcium include dairy products such as milk, cheese, and yogurt; leafy green vegetables like broccoli and kale; fortified cereals and juices; and certain types of fish, such as salmon and sardines. It is important to note that some foods can inhibit the absorption of calcium, including oxalates found in spinach and rhubarb, and phytates found in whole grains and legumes.

If a person is unable to get enough calcium through their diet, they may need to take calcium supplements. However, it is important to talk to a healthcare provider before starting any new supplement regimen, as excessive intake of calcium can lead to negative health effects.

Monocytes are a type of white blood cell that are part of the immune system. They are large cells with a round or oval shape and a nucleus that is typically indented or horseshoe-shaped. Monocytes are produced in the bone marrow and then circulate in the bloodstream, where they can differentiate into other types of immune cells such as macrophages and dendritic cells.

Monocytes play an important role in the body's defense against infection and tissue damage. They are able to engulf and digest foreign particles, microorganisms, and dead or damaged cells, which helps to clear them from the body. Monocytes also produce cytokines, which are signaling molecules that help to coordinate the immune response.

Elevated levels of monocytes in the bloodstream can be a sign of an ongoing infection, inflammation, or other medical conditions such as cancer or autoimmune disorders.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

'Tumor cells, cultured' refers to the process of removing cancerous cells from a tumor and growing them in controlled laboratory conditions. This is typically done by isolating the tumor cells from a patient's tissue sample, then placing them in a nutrient-rich environment that promotes their growth and multiplication.

The resulting cultured tumor cells can be used for various research purposes, including the study of cancer biology, drug development, and toxicity testing. They provide a valuable tool for researchers to better understand the behavior and characteristics of cancer cells outside of the human body, which can lead to the development of more effective cancer treatments.

It is important to note that cultured tumor cells may not always behave exactly the same way as they do in the human body, so findings from cell culture studies must be validated through further research, such as animal models or clinical trials.

The parathyroid glands are four small endocrine glands located in the neck, usually near or behind the thyroid gland. They secrete parathyroid hormone (PTH), which plays a critical role in regulating calcium and phosphate levels in the blood and bones. PTH helps maintain the balance of these minerals by increasing the absorption of calcium from food in the intestines, promoting reabsorption of calcium in the kidneys, and stimulating the release of calcium from bones when needed. Additionally, PTH decreases the excretion of calcium through urine and reduces phosphate reabsorption in the kidneys, leading to increased phosphate excretion. Disorders of the parathyroid glands can result in conditions such as hyperparathyroidism (overactive glands) or hypoparathyroidism (underactive glands), which can have significant impacts on calcium and phosphate homeostasis and overall health.

Cell division is the process by which a single eukaryotic cell (a cell with a true nucleus) divides into two identical daughter cells. This complex process involves several stages, including replication of DNA, separation of chromosomes, and division of the cytoplasm. There are two main types of cell division: mitosis and meiosis.

Mitosis is the type of cell division that results in two genetically identical daughter cells. It is a fundamental process for growth, development, and tissue repair in multicellular organisms. The stages of mitosis include prophase, prometaphase, metaphase, anaphase, and telophase, followed by cytokinesis, which divides the cytoplasm.

Meiosis, on the other hand, is a type of cell division that occurs in the gonads (ovaries and testes) during the production of gametes (sex cells). Meiosis results in four genetically unique daughter cells, each with half the number of chromosomes as the parent cell. This process is essential for sexual reproduction and genetic diversity. The stages of meiosis include meiosis I and meiosis II, which are further divided into prophase, prometaphase, metaphase, anaphase, and telophase.

In summary, cell division is the process by which a single cell divides into two daughter cells, either through mitosis or meiosis. This process is critical for growth, development, tissue repair, and sexual reproduction in multicellular organisms.

Calbindin 1 is a calcium-binding protein that belongs to the family of EF-hand proteins. It is also known as calbindin D-28k, due to its molecular weight of approximately 28 kilodaltons. This protein is widely distributed in various tissues and organisms but is particularly abundant in the nervous system, where it plays crucial roles in calcium homeostasis, neuroprotection, and signal transduction.

In neurons, calbindin 1 is primarily located in the cytoplasm and dendrites, with lower concentrations found in the axons and nerve terminals. It helps regulate intracellular calcium levels by binding to calcium ions (Ca2+) with high affinity and capacity, thereby preventing rapid fluctuations in Ca2+ concentration that could trigger cellular damage or dysfunction.

Calbindin 1 has been implicated in several neuronal processes, including neurotransmitter release, synaptic plasticity, and neuronal excitability. Additionally, it is believed to provide neuroprotection against various insults, such as oxidative stress, glutamate excitotoxicity, and calcium overload, which are associated with neurological disorders like Alzheimer's disease, Parkinson's disease, and epilepsy.

In summary, calbindin 1 is a calcium-binding protein that plays essential roles in maintaining calcium homeostasis, neuroprotection, and neuronal signaling within the nervous system.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Dihydrotachysterol is a synthetic form of vitamin D that is used as a medication to treat hypocalcemia (low levels of calcium in the blood) in people with certain medical conditions, such as hypoparathyroidism and vitamin D deficiency. It works by increasing the absorption of calcium from the gut and promoting the release of calcium from bones into the bloodstream.

Dihydrotachysterol is available in tablet form and is typically taken once or twice a day, with the dosage adjusted based on the individual's response to treatment and serum calcium levels. Common side effects of dihydrotachysterol include hypercalcemia (high levels of calcium in the blood), nausea, vomiting, and constipation. It is important to monitor serum calcium levels regularly while taking this medication to prevent toxicity.

The Cytochrome P-450 (CYP450) enzyme system is a group of enzymes found primarily in the liver, but also in other organs such as the intestines, lungs, and skin. These enzymes play a crucial role in the metabolism and biotransformation of various substances, including drugs, environmental toxins, and endogenous compounds like hormones and fatty acids.

The name "Cytochrome P-450" refers to the unique property of these enzymes to bind to carbon monoxide (CO) and form a complex that absorbs light at a wavelength of 450 nm, which can be detected spectrophotometrically.

The CYP450 enzyme system is involved in Phase I metabolism of xenobiotics, where it catalyzes oxidation reactions such as hydroxylation, dealkylation, and epoxidation. These reactions introduce functional groups into the substrate molecule, which can then undergo further modifications by other enzymes during Phase II metabolism.

There are several families and subfamilies of CYP450 enzymes, each with distinct substrate specificities and functions. Some of the most important CYP450 enzymes include:

1. CYP3A4: This is the most abundant CYP450 enzyme in the human liver and is involved in the metabolism of approximately 50% of all drugs. It also metabolizes various endogenous compounds like steroids, bile acids, and vitamin D.
2. CYP2D6: This enzyme is responsible for the metabolism of many psychotropic drugs, including antidepressants, antipsychotics, and beta-blockers. It also metabolizes some endogenous compounds like dopamine and serotonin.
3. CYP2C9: This enzyme plays a significant role in the metabolism of warfarin, phenytoin, and nonsteroidal anti-inflammatory drugs (NSAIDs).
4. CYP2C19: This enzyme is involved in the metabolism of proton pump inhibitors, antidepressants, and clopidogrel.
5. CYP2E1: This enzyme metabolizes various xenobiotics like alcohol, acetaminophen, and carbon tetrachloride, as well as some endogenous compounds like fatty acids and prostaglandins.

Genetic polymorphisms in CYP450 enzymes can significantly affect drug metabolism and response, leading to interindividual variability in drug efficacy and toxicity. Understanding the role of CYP450 enzymes in drug metabolism is crucial for optimizing pharmacotherapy and minimizing adverse effects.

Keratinocytes are the predominant type of cells found in the epidermis, which is the outermost layer of the skin. These cells are responsible for producing keratin, a tough protein that provides structural support and protection to the skin. Keratinocytes undergo constant turnover, with new cells produced in the basal layer of the epidermis and older cells moving upward and eventually becoming flattened and filled with keratin as they reach the surface of the skin, where they are then shed. They also play a role in the immune response and can release cytokines and other signaling molecules to help protect the body from infection and injury.

Tretinoin is a form of vitamin A that is used in the treatment of acne vulgaris, fine wrinkles, and dark spots caused by aging or sun damage. It works by increasing the turnover of skin cells, helping to unclog pores and promote the growth of new skin cells. Tretinoin is available as a cream, gel, or liquid, and is usually applied to the affected area once a day in the evening. Common side effects include redness, dryness, and peeling of the skin. It is important to avoid sunlight and use sunscreen while using tretinoin, as it can make the skin more sensitive to the sun.

Acute Promyelocytic Leukemia (APL) is a specific subtype of acute myeloid leukemia (AML), a cancer of the blood and bone marrow. It is characterized by the accumulation of abnormal promyelocytes, which are immature white blood cells, in the bone marrow and blood. These abnormal cells are produced due to a genetic mutation that involves the retinoic acid receptor alpha (RARA) gene on chromosome 17, often as a result of a translocation with the promyelocytic leukemia (PML) gene on chromosome 15 [t(15;17)]. This genetic alteration disrupts the normal differentiation and maturation process of the promyelocytes, leading to their uncontrolled proliferation and impaired function.

APL typically presents with symptoms related to decreased blood cell production, such as anemia (fatigue, weakness, shortness of breath), thrombocytopenia (easy bruising, bleeding, or petechiae), and neutropenia (increased susceptibility to infections). Additionally, APL is often associated with a high risk of disseminated intravascular coagulation (DIC), a serious complication characterized by abnormal blood clotting and bleeding.

The treatment for Acute Promyelocytic Leukemia typically involves a combination of chemotherapy and all-trans retinoic acid (ATRA) or arsenic trioxide (ATO) therapy, which target the specific genetic alteration in APL cells. This approach has significantly improved the prognosis for patients with this disease, with many achieving long-term remission and even cures.

'Gene expression regulation' refers to the processes that control whether, when, and where a particular gene is expressed, meaning the production of a specific protein or functional RNA encoded by that gene. This complex mechanism can be influenced by various factors such as transcription factors, chromatin remodeling, DNA methylation, non-coding RNAs, and post-transcriptional modifications, among others. Proper regulation of gene expression is crucial for normal cellular function, development, and maintaining homeostasis in living organisms. Dysregulation of gene expression can lead to various diseases, including cancer and genetic disorders.

Familial Hypophosphatemic Rickets (FHR) is a genetic disorder characterized by impaired reabsorption of phosphate in the kidneys, leading to low levels of phosphate in the blood (hypophosphatemia). This condition results in defective mineralization of bones and teeth, causing rickets in children and osteomalacia in adults.

FHR is typically caused by mutations in the PHEX gene, which encodes a protein that helps regulate phosphate levels in the body. In FHR, the mutation leads to an overproduction of a hormone called fibroblast growth factor 23 (FGF23), which increases phosphate excretion in the urine and decreases the activation of vitamin D, further contributing to hypophosphatemia.

Symptoms of FHR may include bowing of the legs, bone pain, muscle weakness, short stature, dental abnormalities, and skeletal deformities. Treatment typically involves oral phosphate supplements and active forms of vitamin D to correct the hypophosphatemia and improve bone mineralization. Regular monitoring of blood phosphate levels, kidney function, and bone health is essential for effective management of this condition.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

Alkaline phosphatase (ALP) is an enzyme found in various body tissues, including the liver, bile ducts, digestive system, bones, and kidneys. It plays a role in breaking down proteins and minerals, such as phosphate, in the body.

The medical definition of alkaline phosphatase refers to its function as a hydrolase enzyme that removes phosphate groups from molecules at an alkaline pH level. In clinical settings, ALP is often measured through blood tests as a biomarker for various health conditions.

Elevated levels of ALP in the blood may indicate liver or bone diseases, such as hepatitis, cirrhosis, bone fractures, or cancer. Therefore, physicians may order an alkaline phosphatase test to help diagnose and monitor these conditions. However, it is essential to interpret ALP results in conjunction with other diagnostic tests and clinical findings for accurate diagnosis and treatment.

Retinoic acid receptors (RARs) are a type of nuclear receptor proteins that play crucial roles in the regulation of gene transcription. They are activated by retinoic acid, which is a metabolite of vitamin A. There are three subtypes of RARs, namely RARα, RARβ, and RARγ, each encoded by different genes.

Once retinoic acid binds to RARs, they form heterodimers with another type of nuclear receptor called retinoid X receptors (RXRs). The RAR-RXR complex then binds to specific DNA sequences called retinoic acid response elements (RAREs) in the promoter regions of target genes. This binding event leads to the recruitment of coactivator proteins and the modification of chromatin structure, ultimately resulting in the activation or repression of gene transcription.

Retinoic acid and its receptors play essential roles in various biological processes, including embryonic development, cell differentiation, apoptosis, and immune function. In addition, RARs have been implicated in several diseases, such as cancer, where they can act as tumor suppressors or oncogenes depending on the context. Therefore, understanding the mechanisms of RAR signaling has important implications for the development of novel therapeutic strategies for various diseases.

Intestinal absorption refers to the process by which the small intestine absorbs water, nutrients, and electrolytes from food into the bloodstream. This is a critical part of the digestive process, allowing the body to utilize the nutrients it needs and eliminate waste products. The inner wall of the small intestine contains tiny finger-like projections called villi, which increase the surface area for absorption. Nutrients are absorbed into the bloodstream through the walls of the capillaries in these villi, and then transported to other parts of the body for use or storage.

Calcitonin is a hormone that is produced and released by the parafollicular cells (also known as C cells) of the thyroid gland. It plays a crucial role in regulating calcium homeostasis in the body. Specifically, it helps to lower elevated levels of calcium in the blood by inhibiting the activity of osteoclasts, which are bone cells that break down bone tissue and release calcium into the bloodstream. Calcitonin also promotes the uptake of calcium in the bones and increases the excretion of calcium in the urine.

Calcitonin is typically released in response to high levels of calcium in the blood, and its effects help to bring calcium levels back into balance. In addition to its role in calcium regulation, calcitonin may also have other functions in the body, such as modulating immune function and reducing inflammation.

Clinically, synthetic forms of calcitonin are sometimes used as a medication to treat conditions related to abnormal calcium levels, such as hypercalcemia (high blood calcium) or osteoporosis. Calcitonin can be administered as an injection, nasal spray, or oral tablet, depending on the specific formulation and intended use.

Fibroblast Growth Factors (FGFs) are a family of growth factors that play crucial roles in various biological processes, including cell survival, proliferation, migration, and differentiation. They bind to specific tyrosine kinase receptors (FGFRs) on the cell surface, leading to intracellular signaling cascades that regulate gene expression and downstream cellular responses. FGFs are involved in embryonic development, tissue repair, and angiogenesis (the formation of new blood vessels). There are at least 22 distinct FGFs identified in humans, each with unique functions and patterns of expression. Some FGFs, like FGF1 and FGF2, have mitogenic effects on fibroblasts and other cell types, while others, such as FGF7 and FGF10, are essential for epithelial-mesenchymal interactions during organ development. Dysregulation of FGF signaling has been implicated in various pathological conditions, including cancer, fibrosis, and developmental disorders.

Hypocalcemia is a medical condition characterized by an abnormally low level of calcium in the blood. Calcium is a vital mineral that plays a crucial role in various bodily functions, including muscle contraction, nerve impulse transmission, and bone formation. Normal calcium levels in the blood usually range from 8.5 to 10.2 milligrams per deciliter (mg/dL). Hypocalcemia is typically defined as a serum calcium level below 8.5 mg/dL or, when adjusted for albumin (a protein that binds to calcium), below 8.4 mg/dL (ionized calcium).

Hypocalcemia can result from several factors, such as vitamin D deficiency, hypoparathyroidism (underactive parathyroid glands), kidney dysfunction, certain medications, and severe magnesium deficiency. Symptoms of hypocalcemia may include numbness or tingling in the fingers, toes, or lips; muscle cramps or spasms; seizures; and, in severe cases, cognitive impairment or cardiac arrhythmias. Treatment typically involves correcting the underlying cause and administering calcium and vitamin D supplements to restore normal calcium levels in the blood.

Promoter regions in genetics refer to specific DNA sequences located near the transcription start site of a gene. They serve as binding sites for RNA polymerase and various transcription factors that regulate the initiation of gene transcription. These regulatory elements help control the rate of transcription and, therefore, the level of gene expression. Promoter regions can be composed of different types of sequences, such as the TATA box and CAAT box, and their organization and composition can vary between different genes and species.

Drug synergism is a pharmacological concept that refers to the interaction between two or more drugs, where the combined effect of the drugs is greater than the sum of their individual effects. This means that when these drugs are administered together, they produce an enhanced therapeutic response compared to when they are given separately.

Drug synergism can occur through various mechanisms, such as:

1. Pharmacodynamic synergism - When two or more drugs interact with the same target site in the body and enhance each other's effects.
2. Pharmacokinetic synergism - When one drug affects the metabolism, absorption, distribution, or excretion of another drug, leading to an increased concentration of the second drug in the body and enhanced therapeutic effect.
3. Physiochemical synergism - When two drugs interact physically, such as when one drug enhances the solubility or permeability of another drug, leading to improved absorption and bioavailability.

It is important to note that while drug synergism can result in enhanced therapeutic effects, it can also increase the risk of adverse reactions and toxicity. Therefore, healthcare providers must carefully consider the potential benefits and risks when prescribing combinations of drugs with known or potential synergistic effects.

High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.

In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.

HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.

Osteoclasts are large, multinucleated cells that are primarily responsible for bone resorption, a process in which they break down and dissolve the mineralized matrix of bones. They are derived from monocyte-macrophage precursor cells of hematopoietic origin and play a crucial role in maintaining bone homeostasis by balancing bone formation and bone resorption.

Osteoclasts adhere to the bone surface and create an isolated microenvironment, called the "resorption lacuna," between their cell membrane and the bone surface. Here, they release hydrogen ions into the lacuna through a process called proton pumping, which lowers the pH and dissolves the mineral component of the bone matrix. Additionally, osteoclasts secrete proteolytic enzymes, such as cathepsin K, that degrade the organic components, like collagen, in the bone matrix.

An imbalance in osteoclast activity can lead to various bone diseases, including osteoporosis and Paget's disease, where excessive bone resorption results in weakened and fragile bones.

Bone resorption is the process by which bone tissue is broken down and absorbed into the body. It is a normal part of bone remodeling, in which old or damaged bone tissue is removed and new tissue is formed. However, excessive bone resorption can lead to conditions such as osteoporosis, in which bones become weak and fragile due to a loss of density. This process is carried out by cells called osteoclasts, which break down the bone tissue and release minerals such as calcium into the bloodstream.

Hypoparathyroidism is a medical condition characterized by decreased levels or insufficient function of parathyroid hormone (PTH), which is produced and released by the parathyroid glands. These glands are located in the neck, near the thyroid gland, and play a crucial role in regulating calcium and phosphorus levels in the body.

In hypoparathyroidism, low PTH levels result in decreased absorption of calcium from the gut, increased excretion of calcium through the kidneys, and impaired regulation of bone metabolism. This leads to low serum calcium levels (hypocalcemia) and high serum phosphorus levels (hyperphosphatemia).

Symptoms of hypoparathyroidism can include muscle cramps, spasms, or tetany (involuntary muscle contractions), numbness or tingling sensations in the fingers, toes, and around the mouth, fatigue, weakness, anxiety, cognitive impairment, and in severe cases, seizures. Hypoparathyroidism can be caused by various factors, including surgical removal or damage to the parathyroid glands, autoimmune disorders, radiation therapy, genetic defects, or low magnesium levels. Treatment typically involves calcium and vitamin D supplementation to maintain normal serum calcium levels and alleviate symptoms. In some cases, recombinant PTH (Natpara) may be prescribed as well.

Cytosol refers to the liquid portion of the cytoplasm found within a eukaryotic cell, excluding the organelles and structures suspended in it. It is the site of various metabolic activities and contains a variety of ions, small molecules, and enzymes. The cytosol is where many biochemical reactions take place, including glycolysis, protein synthesis, and the regulation of cellular pH. It is also where some organelles, such as ribosomes and vesicles, are located. In contrast to the cytosol, the term "cytoplasm" refers to the entire contents of a cell, including both the cytosol and the organelles suspended within it.

Sodium-phosphate cotransporter proteins, type IIc (NPTIIc), are a subtype of sodium-dependent phosphate transporters that play a crucial role in the regulation of phosphate homeostasis within the body. They are located primarily in the kidney's proximal tubule cells and intestinal epithelial cells.

NPTIIc proteins facilitate the active transport of inorganic phosphate (Pi) ions across the cell membrane, in conjunction with sodium ions (Na+). This symport mechanism allows for the movement of Pi against its concentration gradient, from areas of low concentration to high concentration. The energy required for this process is derived from the electrochemical gradient of sodium ions.

These transporters are essential for maintaining normal phosphate levels in the body, as they help reabsorb a significant portion of filtered phosphate in the kidneys and absorb dietary phosphate in the intestines. Dysregulation of NPTIIc proteins can lead to various disorders related to phosphate homeostasis, such as hypophosphatemia (low serum phosphate levels) or hyperphosphatemia (high serum phosphate levels), which can have detrimental effects on bone health, mineral metabolism, and overall body function.

Up-regulation is a term used in molecular biology and medicine to describe an increase in the expression or activity of a gene, protein, or receptor in response to a stimulus. This can occur through various mechanisms such as increased transcription, translation, or reduced degradation of the molecule. Up-regulation can have important functional consequences, for example, enhancing the sensitivity or response of a cell to a hormone, neurotransmitter, or drug. It is a normal physiological process that can also be induced by disease or pharmacological interventions.

Cycloheximide is an antibiotic that is primarily used in laboratory settings to inhibit protein synthesis in eukaryotic cells. It is derived from the actinobacteria species Streptomyces griseus. In medical terms, it is not used as a therapeutic drug in humans due to its significant side effects, including liver toxicity and potential neurotoxicity. However, it remains a valuable tool in research for studying protein function and cellular processes.

The antibiotic works by binding to the 60S subunit of the ribosome, thereby preventing the transfer RNA (tRNA) from delivering amino acids to the growing polypeptide chain during translation. This inhibition of protein synthesis can be lethal to cells, making cycloheximide a useful tool in studying cellular responses to protein depletion or misregulation.

In summary, while cycloheximide has significant research applications due to its ability to inhibit protein synthesis in eukaryotic cells, it is not used as a therapeutic drug in humans because of its toxic side effects.

Hypercalciuria is a medical condition characterized by an excessive amount of calcium in the urine. It can occur when the body absorbs too much calcium from food, or when the bones release more calcium than usual. In some cases, it may be caused by certain medications, kidney disorders, or genetic factors.

Hypercalciuria can increase the risk of developing kidney stones and other kidney problems. It is often diagnosed through a 24-hour urine collection test that measures the amount of calcium in the urine. Treatment may include changes in diet, increased fluid intake, and medications to help reduce the amount of calcium in the urine.

Calcium metabolism disorders refer to a group of medical conditions that affect the body's ability to properly regulate the levels of calcium in the blood and tissues. Calcium is an essential mineral that plays a critical role in many bodily functions, including bone health, muscle contraction, nerve function, and blood clotting.

There are several types of calcium metabolism disorders, including:

1. Hypocalcemia: This is a condition characterized by low levels of calcium in the blood. It can be caused by various factors such as vitamin D deficiency, hypoparathyroidism, and certain medications. Symptoms may include muscle cramps, spasms, and tingling sensations in the fingers and toes.
2. Hypercalcemia: This is a condition characterized by high levels of calcium in the blood. It can be caused by various factors such as hyperparathyroidism, cancer, and certain medications. Symptoms may include fatigue, weakness, confusion, and kidney stones.
3. Osteoporosis: This is a condition characterized by weak and brittle bones due to low calcium levels in the bones. It can be caused by various factors such as aging, menopause, vitamin D deficiency, and certain medications. Symptoms may include bone fractures and loss of height.
4. Paget's disease: This is a condition characterized by abnormal bone growth and deformities due to disordered calcium metabolism. It can be caused by various factors such as genetics, age, and certain medications. Symptoms may include bone pain, fractures, and deformities.

Treatment for calcium metabolism disorders depends on the underlying cause of the condition. It may involve supplements, medication, dietary changes, or surgery. Proper diagnosis and management are essential to prevent complications such as kidney stones, bone fractures, and neurological damage.

Tetradecanoylphorbol acetate (TPA) is defined as a pharmacological agent that is a derivative of the phorbol ester family. It is a potent tumor promoter and activator of protein kinase C (PKC), a group of enzymes that play a role in various cellular processes such as signal transduction, proliferation, and differentiation. TPA has been widely used in research to study PKC-mediated signaling pathways and its role in cancer development and progression. It is also used in topical treatments for skin conditions such as psoriasis.

Enzyme induction is a process by which the activity or expression of an enzyme is increased in response to some stimulus, such as a drug, hormone, or other environmental factor. This can occur through several mechanisms, including increasing the transcription of the enzyme's gene, stabilizing the mRNA that encodes the enzyme, or increasing the translation of the mRNA into protein.

In some cases, enzyme induction can be a beneficial process, such as when it helps the body to metabolize and clear drugs more quickly. However, in other cases, enzyme induction can have negative consequences, such as when it leads to the increased metabolism of important endogenous compounds or the activation of harmful procarcinogens.

Enzyme induction is an important concept in pharmacology and toxicology, as it can affect the efficacy and safety of drugs and other xenobiotics. It is also relevant to the study of drug interactions, as the induction of one enzyme by a drug can lead to altered metabolism and effects of another drug that is metabolized by the same enzyme.

Gene expression is the process by which the information encoded in a gene is used to synthesize a functional gene product, such as a protein or RNA molecule. This process involves several steps: transcription, RNA processing, and translation. During transcription, the genetic information in DNA is copied into a complementary RNA molecule, known as messenger RNA (mRNA). The mRNA then undergoes RNA processing, which includes adding a cap and tail to the mRNA and splicing out non-coding regions called introns. The resulting mature mRNA is then translated into a protein on ribosomes in the cytoplasm through the process of translation.

The regulation of gene expression is a complex and highly controlled process that allows cells to respond to changes in their environment, such as growth factors, hormones, and stress signals. This regulation can occur at various stages of gene expression, including transcriptional activation or repression, RNA processing, mRNA stability, and translation. Dysregulation of gene expression has been implicated in many diseases, including cancer, genetic disorders, and neurological conditions.

Parathyroid Hormone-Related Protein (PTHrP) is a protein that is encoded by the PTHLH gene in humans. It is structurally similar to parathyroid hormone (PTH) and was initially identified due to its role in humoral hypercalcemia of malignancy, a condition characterized by high levels of calcium in the blood caused by certain types of cancer.

PTHrP has a variety of functions in the body, including regulation of calcium and phosphate homeostasis, cell growth and differentiation, and bone metabolism. It acts through a specific G protein-coupled receptor called the PTH/PTHrP receptor, which is found in many tissues throughout the body, including bone, kidney, and cartilage.

In contrast to PTH, which is primarily produced by the parathyroid glands and regulates calcium levels in the blood, PTHrP is produced by many different types of cells throughout the body. Its expression is regulated in a tissue-specific manner, and its functions can vary depending on the context in which it is produced.

Overall, PTHrP plays important roles in normal physiology as well as in various disease states, including cancer, bone disorders, and developmental abnormalities.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

The Cholesterol Side-Chain Cleavage Enzyme, also known as Steroidogenic Acute Regulatory (StAR) protein or P450scc, is a complex enzymatic system that plays a crucial role in the production of steroid hormones. It is located in the inner mitochondrial membrane of steroid-producing cells, such as those found in the adrenal glands, gonads, and placenta.

The Cholesterol Side-Chain Cleavage Enzyme is responsible for converting cholesterol into pregnenolone, which is the first step in the biosynthesis of all steroid hormones, including cortisol, aldosterone, sex hormones, and vitamin D. This enzymatic complex consists of two components: a flavoprotein called NADPH-cytochrome P450 oxidoreductase, which provides electrons for the reaction, and a cytochrome P450 protein called CYP11A1, which catalyzes the actual cleavage of the cholesterol side chain.

Defects in the Cholesterol Side-Chain Cleavage Enzyme can lead to various genetic disorders, such as congenital lipoid adrenal hyperplasia (CLAH), a rare autosomal recessive disorder characterized by impaired steroidogenesis and accumulation of cholesteryl esters in the adrenal glands and gonads.

Teriparatide is a synthetic form of parathyroid hormone (PTH), which is a natural hormone produced by the parathyroid glands in the body. The medication contains the active fragment of PTH, known as 1-34 PTH, and it is used in medical treatment to stimulate new bone formation and increase bone density.

Teriparatide is primarily prescribed for the management of osteoporosis in postmenopausal women and men with a high risk of fractures who have not responded well to other osteoporosis therapies, such as bisphosphonates. It is administered via subcutaneous injection, typically once daily.

By increasing bone formation and reducing bone resorption, teriparatide helps improve bone strength and structure, ultimately decreasing the risk of fractures in treated individuals. The medication's effects on bone metabolism can lead to improvements in bone mineral density (BMD) and microarchitecture, making it an essential tool for managing severe osteoporosis and reducing fracture risk.

Hydroxylation is a biochemical process that involves the addition of a hydroxyl group (-OH) to a molecule, typically a steroid or xenobiotic compound. This process is primarily catalyzed by enzymes called hydroxylases, which are found in various tissues throughout the body.

In the context of medicine and biochemistry, hydroxylation can have several important functions:

1. Drug metabolism: Hydroxylation is a common way that the liver metabolizes drugs and other xenobiotic compounds. By adding a hydroxyl group to a drug molecule, it becomes more polar and water-soluble, which facilitates its excretion from the body.
2. Steroid hormone biosynthesis: Hydroxylation is an essential step in the biosynthesis of many steroid hormones, including cortisol, aldosterone, and the sex hormones estrogen and testosterone. These hormones are synthesized from cholesterol through a series of enzymatic reactions that involve hydroxylation at various steps.
3. Vitamin D activation: Hydroxylation is also necessary for the activation of vitamin D in the body. In order to become biologically active, vitamin D must undergo two successive hydroxylations, first in the liver and then in the kidneys.
4. Toxin degradation: Some toxic compounds can be rendered less harmful through hydroxylation. For example, phenol, a toxic compound found in cigarette smoke and some industrial chemicals, can be converted to a less toxic form through hydroxylation by enzymes in the liver.

Overall, hydroxylation is an important biochemical process that plays a critical role in various physiological functions, including drug metabolism, hormone biosynthesis, and toxin degradation.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Dactinomycin is an antineoplastic antibiotic, which means it is used to treat cancer. It is specifically used to treat certain types of testicular cancer, Wilms' tumor (a type of kidney cancer that occurs in children), and some gestational trophoblastic tumors (a type of tumor that can develop in the uterus after pregnancy). Dactinomycin works by interfering with the DNA in cancer cells, which prevents them from dividing and growing. It is often used in combination with other chemotherapy drugs as part of a treatment regimen.

Dactinomycin is administered intravenously (through an IV) and its use is usually limited to hospitals or specialized cancer treatment centers due to the need for careful monitoring during administration. Common side effects include nausea, vomiting, and hair loss. More serious side effects can include bone marrow suppression, which can lead to an increased risk of infection, and tissue damage at the site where the drug is injected. Dactinomycin can also cause severe allergic reactions in some people.

It's important to note that dactinomycin should only be used under the supervision of a qualified healthcare professional, as its use requires careful monitoring and management of potential side effects.

PHEX (Phosphate Regulating Endopeptidase Homolog, X-Linked) is a gene that encodes for an enzyme called phosphate regulating neutral endopeptidase. This enzyme is primarily expressed in osteoblasts, which are cells responsible for bone formation.

The main function of the PHEX protein is to regulate the levels of a hormone called fibroblast growth factor 23 (FGF23) by breaking it down. FGF23 plays an essential role in maintaining phosphate homeostasis by regulating its reabsorption in the kidneys and its absorption from the gut.

Inactivating mutations in the PHEX gene can lead to X-linked hypophosphatemia (XLH), a genetic disorder characterized by low levels of phosphate in the blood, impaired bone mineralization, and rickets. In XLH, the production of FGF23 is increased due to the lack of regulation by PHEX, leading to excessive excretion of phosphate in the urine and decreased absorption from the gut. This results in hypophosphatemia, impaired bone mineralization, and other skeletal abnormalities.

A cell line that is derived from tumor cells and has been adapted to grow in culture. These cell lines are often used in research to study the characteristics of cancer cells, including their growth patterns, genetic changes, and responses to various treatments. They can be established from many different types of tumors, such as carcinomas, sarcomas, and leukemias. Once established, these cell lines can be grown and maintained indefinitely in the laboratory, allowing researchers to conduct experiments and studies that would not be feasible using primary tumor cells. It is important to note that tumor cell lines may not always accurately represent the behavior of the original tumor, as they can undergo genetic changes during their time in culture.

Caco-2 cells are a type of human epithelial colorectal adenocarcinoma cell line that is commonly used in scientific research, particularly in the field of drug development and toxicology. These cells are capable of forming a monolayer with tight junctions, which makes them an excellent model for studying intestinal absorption, transport, and metabolism of drugs and other xenobiotic compounds.

Caco-2 cells express many of the transporters and enzymes that are found in the human small intestine, making them a valuable tool for predicting drug absorption and bioavailability in humans. They are also used to study the mechanisms of drug transport across the intestinal epithelium, including passive diffusion and active transport by various transporters.

In addition to their use in drug development, Caco-2 cells are also used to study the toxicological effects of various compounds on human intestinal cells. They can be used to investigate the mechanisms of toxicity, as well as to evaluate the potential for drugs and other compounds to induce intestinal damage or inflammation.

Overall, Caco-2 cells are a widely used and valuable tool in both drug development and toxicology research, providing important insights into the absorption, transport, metabolism, and toxicity of various compounds in the human body.

Dexamethasone is a type of corticosteroid medication, which is a synthetic version of a natural hormone produced by the adrenal glands. It is often used to reduce inflammation and suppress the immune system in a variety of medical conditions, including allergies, asthma, rheumatoid arthritis, and certain skin conditions.

Dexamethasone works by binding to specific receptors in cells, which triggers a range of anti-inflammatory effects. These include reducing the production of chemicals that cause inflammation, suppressing the activity of immune cells, and stabilizing cell membranes.

In addition to its anti-inflammatory effects, dexamethasone can also be used to treat other medical conditions, such as certain types of cancer, brain swelling, and adrenal insufficiency. It is available in a variety of forms, including tablets, liquids, creams, and injectable solutions.

Like all medications, dexamethasone can have side effects, particularly if used for long periods of time or at high doses. These may include mood changes, increased appetite, weight gain, acne, thinning skin, easy bruising, and an increased risk of infections. It is important to follow the instructions of a healthcare provider when taking dexamethasone to minimize the risk of side effects.

Physiologic calcification is the normal deposit of calcium salts in body tissues and organs. It is a natural process that occurs as part of the growth and development of the human body, as well as during the repair and remodeling of tissues.

Calcium is an essential mineral that plays a critical role in many bodily functions, including bone formation, muscle contraction, nerve impulse transmission, and blood clotting. In order to maintain proper levels of calcium in the body, excess calcium that is not needed for these functions may be deposited in various tissues as a normal part of the aging process.

Physiologic calcification typically occurs in areas such as the walls of blood vessels, the lungs, and the heart valves. While these calcifications are generally harmless, they can sometimes lead to complications, particularly if they occur in large amounts or in sensitive areas. For example, calcification of the coronary arteries can increase the risk of heart disease, while calcification of the lung tissue can cause respiratory symptoms.

It is important to note that pathologic calcification, on the other hand, refers to the abnormal deposit of calcium salts in tissues and organs, which can be caused by various medical conditions such as chronic kidney disease, hyperparathyroidism, and certain infections. Pathologic calcification is not a normal process and can lead to serious health complications if left untreated.

Northern blotting is a laboratory technique used in molecular biology to detect and analyze specific RNA molecules (such as mRNA) in a mixture of total RNA extracted from cells or tissues. This technique is called "Northern" blotting because it is analogous to the Southern blotting method, which is used for DNA detection.

The Northern blotting procedure involves several steps:

1. Electrophoresis: The total RNA mixture is first separated based on size by running it through an agarose gel using electrical current. This separates the RNA molecules according to their length, with smaller RNA fragments migrating faster than larger ones.

2. Transfer: After electrophoresis, the RNA bands are denatured (made single-stranded) and transferred from the gel onto a nitrocellulose or nylon membrane using a technique called capillary transfer or vacuum blotting. This step ensures that the order and relative positions of the RNA fragments are preserved on the membrane, similar to how they appear in the gel.

3. Cross-linking: The RNA is then chemically cross-linked to the membrane using UV light or heat treatment, which helps to immobilize the RNA onto the membrane and prevent it from washing off during subsequent steps.

4. Prehybridization: Before adding the labeled probe, the membrane is prehybridized in a solution containing blocking agents (such as salmon sperm DNA or yeast tRNA) to minimize non-specific binding of the probe to the membrane.

5. Hybridization: A labeled nucleic acid probe, specific to the RNA of interest, is added to the prehybridization solution and allowed to hybridize (form base pairs) with its complementary RNA sequence on the membrane. The probe can be either a DNA or an RNA molecule, and it is typically labeled with a radioactive isotope (such as ³²P) or a non-radioactive label (such as digoxigenin).

6. Washing: After hybridization, the membrane is washed to remove unbound probe and reduce background noise. The washing conditions (temperature, salt concentration, and detergent concentration) are optimized based on the stringency required for specific hybridization.

7. Detection: The presence of the labeled probe is then detected using an appropriate method, depending on the type of label used. For radioactive probes, this typically involves exposing the membrane to X-ray film or a phosphorimager screen and analyzing the resulting image. For non-radioactive probes, detection can be performed using colorimetric, chemiluminescent, or fluorescent methods.

8. Data analysis: The intensity of the signal is quantified and compared to controls (such as housekeeping genes) to determine the relative expression level of the RNA of interest. This information can be used for various purposes, such as identifying differentially expressed genes in response to a specific treatment or comparing gene expression levels across different samples or conditions.

Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) is a laboratory technique used in molecular biology to amplify and detect specific DNA sequences. This technique is particularly useful for the detection and quantification of RNA viruses, as well as for the analysis of gene expression.

The process involves two main steps: reverse transcription and polymerase chain reaction (PCR). In the first step, reverse transcriptase enzyme is used to convert RNA into complementary DNA (cDNA) by reading the template provided by the RNA molecule. This cDNA then serves as a template for the PCR amplification step.

In the second step, the PCR reaction uses two primers that flank the target DNA sequence and a thermostable polymerase enzyme to repeatedly copy the targeted cDNA sequence. The reaction mixture is heated and cooled in cycles, allowing the primers to anneal to the template, and the polymerase to extend the new strand. This results in exponential amplification of the target DNA sequence, making it possible to detect even small amounts of RNA or cDNA.

RT-PCR is a sensitive and specific technique that has many applications in medical research and diagnostics, including the detection of viruses such as HIV, hepatitis C virus, and SARS-CoV-2 (the virus that causes COVID-19). It can also be used to study gene expression, identify genetic mutations, and diagnose genetic disorders.

Abietanes are a subclass of diterpenes, which are a type of organic compound consisting of four isoprene units and having the chemical formula C20H32. Diterpenes are synthesized by a wide variety of plants and some animals, and they have diverse biological activities.

Abietanes are characterized by a distinctive carbon skeleton that contains three six-membered rings arranged in a linear fashion, with the fourth ring being a five-membered ring. This particular structure is derived from geranylgeranyl pyrophosphate (GGPP), a precursor to many diterpenes.

Abietanes are found in various natural sources, including pine resin, where they exist as resin acids such as abietic acid, pimaric acid, and isopimaric acid. These compounds have been studied for their potential medicinal properties, including anti-inflammatory, antimicrobial, and anticancer activities. However, more research is needed to fully understand the therapeutic potential of abietanes and to develop safe and effective treatments based on these compounds.

Secondary hyperparathyroidism is a condition characterized by an overproduction of parathyroid hormone (PTH) from the parathyroid glands due to hypocalcemia (low levels of calcium in the blood). This condition is usually a result of chronic kidney disease, where the kidneys fail to convert vitamin D into its active form, leading to decreased absorption of calcium in the intestines. The body responds by increasing PTH production to maintain normal calcium levels, but over time, this results in high PTH levels and associated complications such as bone disease, kidney stones, and cardiovascular calcification.

Transient receptor potential vanilloid (TRPV) cation channels are a subfamily of transient receptor potential (TRP) channels, which are non-selective cation channels that play important roles in various physiological processes such as nociception, thermosensation, and mechanosensation. TRPV channels are activated by a variety of stimuli including temperature, chemical ligands, and mechanical forces.

TRPV channels are composed of six transmembrane domains with intracellular N- and C-termini. The TRPV subfamily includes six members: TRPV1 to TRPV6. Among them, TRPV1 is also known as the vanilloid receptor 1 (VR1) and is activated by capsaicin, the active component of hot chili peppers, as well as noxious heat. TRPV2 is activated by noxious heat and mechanical stimuli, while TRPV3 and TRPV4 are activated by warm temperatures and various chemical ligands. TRPV5 and TRPV6 are primarily involved in calcium transport and are activated by low pH and divalent cations.

TRPV channels play important roles in pain sensation, neurogenic inflammation, and temperature perception. Dysfunction of these channels has been implicated in various pathological conditions such as chronic pain, inflammatory diseases, and cancer. Therefore, TRPV channels are considered promising targets for the development of novel therapeutics for these conditions.

"Competitive binding" is a term used in pharmacology and biochemistry to describe the behavior of two or more molecules (ligands) competing for the same binding site on a target protein or receptor. In this context, "binding" refers to the physical interaction between a ligand and its target.

When a ligand binds to a receptor, it can alter the receptor's function, either activating or inhibiting it. If multiple ligands compete for the same binding site, they will compete to bind to the receptor. The ability of each ligand to bind to the receptor is influenced by its affinity for the receptor, which is a measure of how strongly and specifically the ligand binds to the receptor.

In competitive binding, if one ligand is present in high concentrations, it can prevent other ligands with lower affinity from binding to the receptor. This is because the higher-affinity ligand will have a greater probability of occupying the binding site and blocking access to the other ligands. The competition between ligands can be described mathematically using equations such as the Langmuir isotherm, which describes the relationship between the concentration of ligand and the fraction of receptors that are occupied by the ligand.

Competitive binding is an important concept in drug development, as it can be used to predict how different drugs will interact with their targets and how they may affect each other's activity. By understanding the competitive binding properties of a drug, researchers can optimize its dosage and delivery to maximize its therapeutic effect while minimizing unwanted side effects.

Calcium-binding proteins (CaBPs) are a diverse group of proteins that have the ability to bind calcium ions (Ca^2+^) with high affinity and specificity. They play crucial roles in various cellular processes, including signal transduction, muscle contraction, neurotransmitter release, and protection against oxidative stress.

The binding of calcium ions to these proteins induces conformational changes that can either activate or inhibit their functions. Some well-known CaBPs include calmodulin, troponin C, S100 proteins, and parvalbumins. These proteins are essential for maintaining calcium homeostasis within cells and for mediating the effects of calcium as a second messenger in various cellular signaling pathways.

The intestinal mucosa is the innermost layer of the intestines, which comes into direct contact with digested food and microbes. It is a specialized epithelial tissue that plays crucial roles in nutrient absorption, barrier function, and immune defense. The intestinal mucosa is composed of several cell types, including absorptive enterocytes, mucus-secreting goblet cells, hormone-producing enteroendocrine cells, and immune cells such as lymphocytes and macrophages.

The surface of the intestinal mucosa is covered by a single layer of epithelial cells, which are joined together by tight junctions to form a protective barrier against harmful substances and microorganisms. This barrier also allows for the selective absorption of nutrients into the bloodstream. The intestinal mucosa also contains numerous lymphoid follicles, known as Peyer's patches, which are involved in immune surveillance and defense against pathogens.

In addition to its role in absorption and immunity, the intestinal mucosa is also capable of producing hormones that regulate digestion and metabolism. Dysfunction of the intestinal mucosa can lead to various gastrointestinal disorders, such as inflammatory bowel disease, celiac disease, and food allergies.

Transcription factors are proteins that play a crucial role in regulating gene expression by controlling the transcription of DNA to messenger RNA (mRNA). They function by binding to specific DNA sequences, known as response elements, located in the promoter region or enhancer regions of target genes. This binding can either activate or repress the initiation of transcription, depending on the properties and interactions of the particular transcription factor. Transcription factors often act as part of a complex network of regulatory proteins that determine the precise spatiotemporal patterns of gene expression during development, differentiation, and homeostasis in an organism.

A ligand, in the context of biochemistry and medicine, is a molecule that binds to a specific site on a protein or a larger biomolecule, such as an enzyme or a receptor. This binding interaction can modify the function or activity of the target protein, either activating it or inhibiting it. Ligands can be small molecules, like hormones or neurotransmitters, or larger structures, like antibodies. The study of ligand-protein interactions is crucial for understanding cellular processes and developing drugs, as many therapeutic compounds function by binding to specific targets within the body.

Glucuronidase is an enzyme that catalyzes the hydrolysis of glucuronic acid from various substrates, including molecules that have been conjugated with glucuronic acid as part of the detoxification process in the body. This enzyme plays a role in the breakdown and elimination of certain drugs, toxins, and endogenous compounds, such as bilirubin. It is found in various tissues and organisms, including humans, bacteria, and insects. In clinical contexts, glucuronidase activity may be measured to assess liver function or to identify the presence of certain bacterial infections.

U937 cells are a type of human histiocytic lymphoma cell line that is commonly used in scientific research and studies. They are derived from the peripheral blood of a patient with histiocytic lymphoma, which is a rare type of cancer that affects the immune system's cells called histiocytes.

U937 cells have a variety of uses in research, including studying the mechanisms of cancer cell growth and proliferation, testing the effects of various drugs and treatments on cancer cells, and investigating the role of different genes and proteins in cancer development and progression. These cells are easy to culture and maintain in the laboratory, making them a popular choice for researchers in many fields.

It is important to note that while U937 cells can provide valuable insights into the behavior of cancer cells, they do not necessarily reflect the complexity and diversity of human cancers. Therefore, findings from studies using these cells should be validated in more complex models or clinical trials before being applied to patient care.

A Structure-Activity Relationship (SAR) in the context of medicinal chemistry and pharmacology refers to the relationship between the chemical structure of a drug or molecule and its biological activity or effect on a target protein, cell, or organism. SAR studies aim to identify patterns and correlations between structural features of a compound and its ability to interact with a specific biological target, leading to a desired therapeutic response or undesired side effects.

By analyzing the SAR, researchers can optimize the chemical structure of lead compounds to enhance their potency, selectivity, safety, and pharmacokinetic properties, ultimately guiding the design and development of novel drugs with improved efficacy and reduced toxicity.

"Response elements" is a term used in molecular biology, particularly in the study of gene regulation. Response elements are specific DNA sequences that can bind to transcription factors, which are proteins that regulate gene expression. When a transcription factor binds to a response element, it can either activate or repress the transcription of the nearby gene.

Response elements are often found in the promoter region of genes and are typically short, conserved sequences that can be recognized by specific transcription factors. The binding of a transcription factor to a response element can lead to changes in chromatin structure, recruitment of co-activators or co-repressors, and ultimately, the regulation of gene expression.

Response elements are important for many biological processes, including development, differentiation, and response to environmental stimuli such as hormones, growth factors, and stress. The specificity of transcription factor binding to response elements allows for precise control of gene expression in response to changing conditions within the cell or organism.

Osteopontin (OPN) is a phosphorylated glycoprotein that is widely distributed in many tissues, including bone, teeth, and mineralized tissues. It plays important roles in various biological processes such as bone remodeling, immune response, wound healing, and tissue repair. In the skeletal system, osteopontin is involved in the regulation of bone formation and resorption by modulating the activity of osteoclasts and osteoblasts. It also plays a role in the development of chronic inflammatory diseases such as rheumatoid arthritis, atherosclerosis, and cancer metastasis to bones. Osteopontin is considered a potential biomarker for various disease states, including bone turnover, cardiovascular disease, and cancer progression.

Transfection is a term used in molecular biology that refers to the process of deliberately introducing foreign genetic material (DNA, RNA or artificial gene constructs) into cells. This is typically done using chemical or physical methods, such as lipofection or electroporation. Transfection is widely used in research and medical settings for various purposes, including studying gene function, producing proteins, developing gene therapies, and creating genetically modified organisms. It's important to note that transfection is different from transduction, which is the process of introducing genetic material into cells using viruses as vectors.

Lithocholic acid (LCA) is a secondary bile acid that is produced in the liver by bacterial modification of primary bile acids, specifically chenodeoxycholic acid. It is a steroid acid that plays a role in various physiological processes such as cholesterol metabolism, drug absorption, and gut microbiota regulation. However, high levels of LCA can be toxic to the liver and have been linked to several diseases, including colon cancer and cholestatic liver diseases.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Cell proliferation is the process by which cells increase in number, typically through the process of cell division. In the context of biology and medicine, it refers to the reproduction of cells that makes up living tissue, allowing growth, maintenance, and repair. It involves several stages including the transition from a phase of quiescence (G0 phase) to an active phase (G1 phase), DNA replication in the S phase, and mitosis or M phase, where the cell divides into two daughter cells.

Abnormal or uncontrolled cell proliferation is a characteristic feature of many diseases, including cancer, where deregulated cell cycle control leads to excessive and unregulated growth of cells, forming tumors that can invade surrounding tissues and metastasize to distant sites in the body.

Sialglycoproteins are a type of glycoprotein that have sialic acid as the terminal sugar in their oligosaccharide chains. These complex molecules are abundant on the surface of many cell types and play important roles in various biological processes, including cell recognition, cell-cell interactions, and protection against proteolytic degradation.

The presence of sialic acid on the outermost part of these glycoproteins makes them negatively charged, which can affect their interaction with other molecules such as lectins, antibodies, and enzymes. Sialglycoproteins are also involved in the regulation of various physiological functions, including blood coagulation, inflammation, and immune response.

Abnormalities in sialglycoprotein expression or structure have been implicated in several diseases, such as cancer, autoimmune disorders, and neurodegenerative conditions. Therefore, understanding the biology of sialoglycoproteins is important for developing new diagnostic and therapeutic strategies for these diseases.

Prostatic neoplasms refer to abnormal growths in the prostate gland, which can be benign or malignant. The term "neoplasm" simply means new or abnormal tissue growth. When it comes to the prostate, neoplasms are often referred to as tumors.

Benign prostatic neoplasms, such as prostate adenomas, are non-cancerous overgrowths of prostate tissue. They usually grow slowly and do not spread to other parts of the body. While they can cause uncomfortable symptoms like difficulty urinating, they are generally not life-threatening.

Malignant prostatic neoplasms, on the other hand, are cancerous growths. The most common type of prostate cancer is adenocarcinoma, which arises from the glandular cells in the prostate. Prostate cancer often grows slowly and may not cause any symptoms for many years. However, some types of prostate cancer can be aggressive and spread quickly to other parts of the body, such as the bones or lymph nodes.

It's important to note that while prostate neoplasms can be concerning, early detection and treatment can significantly improve outcomes for many men. Regular check-ups with a healthcare provider are key to monitoring prostate health and catching any potential issues early on.

Acute myeloid leukemia (AML) is a type of cancer that originates in the bone marrow, the soft inner part of certain bones where new blood cells are made. In AML, the immature cells, called blasts, in the bone marrow fail to mature into normal blood cells. Instead, these blasts accumulate and interfere with the production of normal blood cells, leading to a shortage of red blood cells (anemia), platelets (thrombocytopenia), and normal white blood cells (leukopenia).

AML is called "acute" because it can progress quickly and become severe within days or weeks without treatment. It is a type of myeloid leukemia, which means that it affects the myeloid cells in the bone marrow. Myeloid cells are a type of white blood cell that includes monocytes and granulocytes, which help fight infection and defend the body against foreign invaders.

In AML, the blasts can build up in the bone marrow and spread to other parts of the body, including the blood, lymph nodes, liver, spleen, and brain. This can cause a variety of symptoms, such as fatigue, fever, frequent infections, easy bruising or bleeding, and weight loss.

AML is typically treated with a combination of chemotherapy, radiation therapy, and/or stem cell transplantation. The specific treatment plan will depend on several factors, including the patient's age, overall health, and the type and stage of the leukemia.

Bone development, also known as ossification, is the process by which bone tissue is formed and grows. This complex process involves several different types of cells, including osteoblasts, which produce new bone matrix, and osteoclasts, which break down and resorb existing bone tissue.

There are two main types of bone development: intramembranous and endochondral ossification. Intramembranous ossification occurs when bone tissue forms directly from connective tissue, while endochondral ossification involves the formation of a cartilage model that is later replaced by bone.

During fetal development, most bones develop through endochondral ossification, starting as a cartilage template that is gradually replaced by bone tissue. However, some bones, such as those in the skull and clavicles, develop through intramembranous ossification.

Bone development continues after birth, with new bone tissue being laid down and existing tissue being remodeled throughout life. This ongoing process helps to maintain the strength and integrity of the skeleton, allowing it to adapt to changing mechanical forces and repair any damage that may occur.

Macrophages are a type of white blood cell that are an essential part of the immune system. They are large, specialized cells that engulf and destroy foreign substances, such as bacteria, viruses, parasites, and fungi, as well as damaged or dead cells. Macrophages are found throughout the body, including in the bloodstream, lymph nodes, spleen, liver, lungs, and connective tissues. They play a critical role in inflammation, immune response, and tissue repair and remodeling.

Macrophages originate from monocytes, which are a type of white blood cell produced in the bone marrow. When monocytes enter the tissues, they differentiate into macrophages, which have a larger size and more specialized functions than monocytes. Macrophages can change their shape and move through tissues to reach sites of infection or injury. They also produce cytokines, chemokines, and other signaling molecules that help coordinate the immune response and recruit other immune cells to the site of infection or injury.

Macrophages have a variety of surface receptors that allow them to recognize and respond to different types of foreign substances and signals from other cells. They can engulf and digest foreign particles, bacteria, and viruses through a process called phagocytosis. Macrophages also play a role in presenting antigens to T cells, which are another type of immune cell that helps coordinate the immune response.

Overall, macrophages are crucial for maintaining tissue homeostasis, defending against infection, and promoting wound healing and tissue repair. Dysregulation of macrophage function has been implicated in a variety of diseases, including cancer, autoimmune disorders, and chronic inflammatory conditions.

REceptor Activator of NF-kB (RANK) Ligand is a type of protein that plays a crucial role in the immune system and bone metabolism. It belongs to the tumor necrosis factor (TNF) superfamily and is primarily produced by osteoblasts, which are cells responsible for bone formation.

RANK Ligand binds to its receptor RANK, which is found on the surface of osteoclasts, a type of cell involved in bone resorption or breakdown. The binding of RANK Ligand to RANK activates signaling pathways that promote the differentiation, activation, and survival of osteoclasts, thereby increasing bone resorption.

Abnormalities in the RANKL-RANK signaling pathway have been implicated in various bone diseases, such as osteoporosis, rheumatoid arthritis, and certain types of cancer that metastasize to bones. Therefore, targeting this pathway with therapeutic agents has emerged as a promising approach for the treatment of these conditions.

Nephrectomy is a surgical procedure in which all or part of a kidney is removed. It may be performed due to various reasons such as severe kidney damage, kidney cancer, or living donor transplantation. The type of nephrectomy depends on the reason for the surgery - a simple nephrectomy involves removing only the affected portion of the kidney, while a radical nephrectomy includes removal of the whole kidney along with its surrounding tissues like the adrenal gland and lymph nodes.

Sarcoidosis is a multi-system disorder characterized by the formation of granulomas (small clumps of inflammatory cells) in various organs, most commonly the lungs and lymphatic system. These granulomas can impair the function of the affected organ(s), leading to a variety of symptoms. The exact cause of sarcoidosis is unknown, but it's thought to be an overactive immune response to an unknown antigen, possibly triggered by an infection, chemical exposure, or another environmental factor.

The diagnosis of sarcoidosis typically involves a combination of clinical evaluation, imaging studies (such as chest X-rays and CT scans), and laboratory tests (including blood tests and biopsies). While there is no cure for sarcoidosis, treatment may be necessary to manage symptoms and prevent complications. Corticosteroids are often used to suppress the immune system and reduce inflammation, while other medications may be prescribed to treat specific organ involvement or symptoms. In some cases, sarcoidosis may resolve on its own without any treatment.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

Western blotting is a laboratory technique used in molecular biology to detect and quantify specific proteins in a mixture of many different proteins. This technique is commonly used to confirm the expression of a protein of interest, determine its size, and investigate its post-translational modifications. The name "Western" blotting distinguishes this technique from Southern blotting (for DNA) and Northern blotting (for RNA).

The Western blotting procedure involves several steps:

1. Protein extraction: The sample containing the proteins of interest is first extracted, often by breaking open cells or tissues and using a buffer to extract the proteins.
2. Separation of proteins by electrophoresis: The extracted proteins are then separated based on their size by loading them onto a polyacrylamide gel and running an electric current through the gel (a process called sodium dodecyl sulfate-polyacrylamide gel electrophoresis or SDS-PAGE). This separates the proteins according to their molecular weight, with smaller proteins migrating faster than larger ones.
3. Transfer of proteins to a membrane: After separation, the proteins are transferred from the gel onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric current in a process called blotting. This creates a replica of the protein pattern on the gel but now immobilized on the membrane for further analysis.
4. Blocking: The membrane is then blocked with a blocking agent, such as non-fat dry milk or bovine serum albumin (BSA), to prevent non-specific binding of antibodies in subsequent steps.
5. Primary antibody incubation: A primary antibody that specifically recognizes the protein of interest is added and allowed to bind to its target protein on the membrane. This step may be performed at room temperature or 4°C overnight, depending on the antibody's properties.
6. Washing: The membrane is washed with a buffer to remove unbound primary antibodies.
7. Secondary antibody incubation: A secondary antibody that recognizes the primary antibody (often coupled to an enzyme or fluorophore) is added and allowed to bind to the primary antibody. This step may involve using a horseradish peroxidase (HRP)-conjugated or alkaline phosphatase (AP)-conjugated secondary antibody, depending on the detection method used later.
8. Washing: The membrane is washed again to remove unbound secondary antibodies.
9. Detection: A detection reagent is added to visualize the protein of interest by detecting the signal generated from the enzyme-conjugated or fluorophore-conjugated secondary antibody. This can be done using chemiluminescent, colorimetric, or fluorescent methods.
10. Analysis: The resulting image is analyzed to determine the presence and quantity of the protein of interest in the sample.

Western blotting is a powerful technique for identifying and quantifying specific proteins within complex mixtures. It can be used to study protein expression, post-translational modifications, protein-protein interactions, and more. However, it requires careful optimization and validation to ensure accurate and reproducible results.

The small intestine is the portion of the gastrointestinal tract that extends from the pylorus of the stomach to the beginning of the large intestine (cecum). It plays a crucial role in the digestion and absorption of nutrients from food. The small intestine is divided into three parts: the duodenum, jejunum, and ileum.

1. Duodenum: This is the shortest and widest part of the small intestine, approximately 10 inches long. It receives chyme (partially digested food) from the stomach and begins the process of further digestion with the help of various enzymes and bile from the liver and pancreas.
2. Jejunum: The jejunum is the middle section, which measures about 8 feet in length. It has a large surface area due to the presence of circular folds (plicae circulares), finger-like projections called villi, and microvilli on the surface of the absorptive cells (enterocytes). These structures increase the intestinal surface area for efficient absorption of nutrients, electrolytes, and water.
3. Ileum: The ileum is the longest and final section of the small intestine, spanning about 12 feet. It continues the absorption process, mainly of vitamin B12, bile salts, and any remaining nutrients. At the end of the ileum, there is a valve called the ileocecal valve that prevents backflow of contents from the large intestine into the small intestine.

The primary function of the small intestine is to absorb the majority of nutrients, electrolytes, and water from ingested food. The mucosal lining of the small intestine contains numerous goblet cells that secrete mucus, which protects the epithelial surface and facilitates the movement of chyme through peristalsis. Additionally, the small intestine hosts a diverse community of microbiota, which contributes to various physiological functions, including digestion, immunity, and protection against pathogens.

Sodium-phosphate cotransporter proteins, type IIa (NaPi-IIa), are a subtype of membrane transport proteins that facilitate the active transport of sodium and phosphate ions across the cell membrane. They play a crucial role in maintaining phosphate homeostasis within the body by regulating the reabsorption of phosphate in the kidney's proximal tubules.

NaPi-IIa proteins are located on the brush border membrane of the proximal tubule cells and function to couple the movement of sodium ions down its electrochemical gradient into the cell with the influx of phosphate ions against its concentration gradient, from the lumen into the cell. This process is driven by the sodium-potassium ATPase pump, which maintains a low intracellular sodium concentration and a negative membrane potential.

NaPi-IIa proteins are encoded by the SLC34A1 gene in humans and are subject to regulation by various hormonal and physiological factors, such as parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and dietary phosphate intake. Dysregulation of NaPi-IIa function has been implicated in several kidney diseases and disorders of phosphate homeostasis, such as hyperphosphatemia and hypophosphatemic rickets.

Gene expression regulation, enzymologic refers to the biochemical processes and mechanisms that control the transcription and translation of specific genes into functional proteins or enzymes. This regulation is achieved through various enzymatic activities that can either activate or repress gene expression at different levels, such as chromatin remodeling, transcription factor activation, mRNA processing, and protein degradation.

Enzymologic regulation of gene expression involves the action of specific enzymes that catalyze chemical reactions involved in these processes. For example, histone-modifying enzymes can alter the structure of chromatin to make genes more or less accessible for transcription, while RNA polymerase and its associated factors are responsible for transcribing DNA into mRNA. Additionally, various enzymes are involved in post-transcriptional modifications of mRNA, such as splicing, capping, and tailing, which can affect the stability and translation of the transcript.

Overall, the enzymologic regulation of gene expression is a complex and dynamic process that allows cells to respond to changes in their environment and maintain proper physiological function.

Signal transduction is the process by which a cell converts an extracellular signal, such as a hormone or neurotransmitter, into an intracellular response. This involves a series of molecular events that transmit the signal from the cell surface to the interior of the cell, ultimately resulting in changes in gene expression, protein activity, or metabolism.

The process typically begins with the binding of the extracellular signal to a receptor located on the cell membrane. This binding event activates the receptor, which then triggers a cascade of intracellular signaling molecules, such as second messengers, protein kinases, and ion channels. These molecules amplify and propagate the signal, ultimately leading to the activation or inhibition of specific cellular responses.

Signal transduction pathways are highly regulated and can be modulated by various factors, including other signaling molecules, post-translational modifications, and feedback mechanisms. Dysregulation of these pathways has been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

A "knockout" mouse is a genetically engineered mouse in which one or more genes have been deleted or "knocked out" using molecular biology techniques. This allows researchers to study the function of specific genes and their role in various biological processes, as well as potential associations with human diseases. The mice are generated by introducing targeted DNA modifications into embryonic stem cells, which are then used to create a live animal. Knockout mice have been widely used in biomedical research to investigate gene function, disease mechanisms, and potential therapeutic targets.

In medical terms, the skin is the largest organ of the human body. It consists of two main layers: the epidermis (outer layer) and dermis (inner layer), as well as accessory structures like hair follicles, sweat glands, and oil glands. The skin plays a crucial role in protecting us from external factors such as bacteria, viruses, and environmental hazards, while also regulating body temperature and enabling the sense of touch.

Leukemia, myeloid is a type of cancer that originates in the bone marrow, where blood cells are produced. Myeloid leukemia affects the myeloid cells, which include red blood cells, platelets, and most types of white blood cells. In this condition, the bone marrow produces abnormal myeloid cells that do not mature properly and accumulate in the bone marrow and blood. These abnormal cells hinder the production of normal blood cells, leading to various symptoms such as anemia, fatigue, increased risk of infections, and easy bruising or bleeding.

There are several types of myeloid leukemias, including acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). AML progresses rapidly and requires immediate treatment, while CML tends to progress more slowly. The exact causes of myeloid leukemia are not fully understood, but risk factors include exposure to radiation or certain chemicals, smoking, genetic disorders, and a history of chemotherapy or other cancer treatments.

Dietary Phosphorus is a mineral that is an essential nutrient for human health. It is required for the growth, maintenance, and repair of body tissues, including bones and teeth. Phosphorus is also necessary for the production of energy, the formation of DNA and RNA, and the regulation of various physiological processes.

In the diet, phosphorus is primarily found in protein-containing foods such as meat, poultry, fish, dairy products, legumes, and nuts. It can also be found in processed foods that contain additives such as phosphoric acid, which is used to enhance flavor or as a preservative.

The recommended daily intake of phosphorus for adults is 700 milligrams (mg) per day. However, it's important to note that excessive intake of phosphorus, particularly from supplements and fortified foods, can lead to health problems such as kidney damage and calcification of soft tissues. Therefore, it's recommended to obtain phosphorus primarily from whole foods rather than supplements.

Hormones are defined as chemical messengers that are produced by endocrine glands or specialized cells and are transported through the bloodstream to tissues and organs, where they elicit specific responses. They play crucial roles in regulating various physiological processes such as growth, development, metabolism, reproduction, and mood. Examples of hormones include insulin, estrogen, testosterone, adrenaline, and thyroxine.

Dimethyl Sulfoxide (DMSO) is an organosulfur compound with the formula (CH3)2SO. It is a polar aprotic solvent, which means it can dissolve both polar and nonpolar compounds. DMSO has a wide range of uses in industry and in laboratory research, including as a cryoprotectant, a solvent for pharmaceuticals, and a penetration enhancer in topical formulations.

In medicine, DMSO is used as a topical analgesic and anti-inflammatory agent. It works by increasing the flow of blood and other fluids to the site of application, which can help to reduce pain and inflammation. DMSO is also believed to have antioxidant properties, which may contribute to its therapeutic effects.

It's important to note that while DMSO has been studied for various medical uses, its effectiveness for many conditions is not well established, and it can have side effects, including skin irritation and a garlic-like taste or odor in the mouth after application. It should be used under the supervision of a healthcare provider.

Homeostasis is a fundamental concept in the field of medicine and physiology, referring to the body's ability to maintain a stable internal environment, despite changes in external conditions. It is the process by which biological systems regulate their internal environment to remain in a state of dynamic equilibrium. This is achieved through various feedback mechanisms that involve sensors, control centers, and effectors, working together to detect, interpret, and respond to disturbances in the system.

For example, the body maintains homeostasis through mechanisms such as temperature regulation (through sweating or shivering), fluid balance (through kidney function and thirst), and blood glucose levels (through insulin and glucagon secretion). When homeostasis is disrupted, it can lead to disease or dysfunction in the body.

In summary, homeostasis is the maintenance of a stable internal environment within biological systems, through various regulatory mechanisms that respond to changes in external conditions.

Mediator Complex Subunit 1 (MED1) is a protein that is a component of the mediator complex, which is a multi-protein complex that acts as a bridge between transcription factors and RNA polymerase II to regulate gene expression. MED1 is also known as TRAP220 or DRIP205, and it plays a role in the recruitment of the mediator complex to specific target genes. It contains several domains that are involved in protein-protein interactions, including a PHD finger domain, a bromodomain, and a proline-rich region. MED1 has been implicated in various cellular processes, such as cell cycle regulation, differentiation, and development, and its dysregulation has been associated with several diseases, including cancer.

The cell nucleus is a membrane-bound organelle found in the eukaryotic cells (cells with a true nucleus). It contains most of the cell's genetic material, organized as DNA molecules in complex with proteins, RNA molecules, and histones to form chromosomes.

The primary function of the cell nucleus is to regulate and control the activities of the cell, including growth, metabolism, protein synthesis, and reproduction. It also plays a crucial role in the process of mitosis (cell division) by separating and protecting the genetic material during this process. The nuclear membrane, or nuclear envelope, surrounding the nucleus is composed of two lipid bilayers with numerous pores that allow for the selective transport of molecules between the nucleoplasm (nucleus interior) and the cytoplasm (cell exterior).

The cell nucleus is a vital structure in eukaryotic cells, and its dysfunction can lead to various diseases, including cancer and genetic disorders.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Parturient paresis, also known as Eclampsia or Puerperal eclampsia, is a serious condition that can occur during pregnancy or after childbirth. It is characterized by the onset of seizures (convulsions) and coma in a woman who has previously developed high blood pressure and proteinuria (protein in the urine) – a condition known as preeclampsia.

Eclampsia is considered a medical emergency, and it can lead to severe complications for both the mother and the baby if not promptly treated. The exact cause of eclampsia is not fully understood, but it is thought to be related to problems with the blood vessels that supply the placenta.

Symptoms of eclampsia include high blood pressure, severe headaches, visual disturbances, nausea and vomiting, and sudden weight gain. If left untreated, eclampsia can lead to serious complications such as brain damage, stroke, kidney failure, and even death for the mother and the baby.

Treatment typically involves close monitoring of the mother and the baby, medication to control seizures and lower blood pressure, and delivery of the baby if necessary. In some cases, eclampsia may occur after the baby has been delivered, in which case it is known as postpartum eclampsia.

Antineoplastic agents are a class of drugs used to treat malignant neoplasms or cancer. These agents work by inhibiting the growth and proliferation of cancer cells, either by killing them or preventing their division and replication. Antineoplastic agents can be classified based on their mechanism of action, such as alkylating agents, antimetabolites, topoisomerase inhibitors, mitotic inhibitors, and targeted therapy agents.

Alkylating agents work by adding alkyl groups to DNA, which can cause cross-linking of DNA strands and ultimately lead to cell death. Antimetabolites interfere with the metabolic processes necessary for DNA synthesis and replication, while topoisomerase inhibitors prevent the relaxation of supercoiled DNA during replication. Mitotic inhibitors disrupt the normal functioning of the mitotic spindle, which is essential for cell division. Targeted therapy agents are designed to target specific molecular abnormalities in cancer cells, such as mutated oncogenes or dysregulated signaling pathways.

It's important to note that antineoplastic agents can also affect normal cells and tissues, leading to various side effects such as nausea, vomiting, hair loss, and myelosuppression (suppression of bone marrow function). Therefore, the use of these drugs requires careful monitoring and management of their potential adverse effects.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

Growth inhibitors, in a medical context, refer to substances or agents that reduce or prevent the growth and proliferation of cells. They play an essential role in regulating normal cellular growth and can be used in medical treatments to control the excessive growth of unwanted cells, such as cancer cells.

There are two main types of growth inhibitors:

1. Endogenous growth inhibitors: These are naturally occurring molecules within the body that help regulate cell growth and division. Examples include retinoids, which are vitamin A derivatives, and interferons, which are signaling proteins released by host cells in response to viruses.

2. Exogenous growth inhibitors: These are synthetic or natural substances from outside the body that can be used to inhibit cell growth. Many chemotherapeutic agents and targeted therapies for cancer treatment fall into this category. They work by interfering with specific pathways involved in cell division, such as DNA replication or mitosis, or by inducing apoptosis (programmed cell death) in cancer cells.

It is important to note that growth inhibitors may also affect normal cells, which can lead to side effects during treatment. The challenge for medical researchers is to develop targeted therapies that specifically inhibit the growth of abnormal cells while minimizing harm to healthy cells.

Cyclin C is a type of cyclin protein that plays a crucial role in the regulation of the cell cycle, which is the process by which cells grow and divide. Specifically, Cyclin C is involved in the transition from the G1 phase to the S phase of the cell cycle, during which DNA replication occurs.

Cyclin C forms a complex with cyclin-dependent kinase 8 (CDK8) and other regulatory subunits to form the CDK8 module, which is part of the mediator complex that regulates gene transcription. The activity of Cyclin C/CDK8 is regulated by various mechanisms, including phosphorylation and degradation, to ensure proper control of the cell cycle and prevent uncontrolled cell growth and division.

Mutations in the gene encoding Cyclin C have been associated with certain types of cancer, highlighting its importance in maintaining genomic stability and preventing tumorigenesis.

Down-regulation is a process that occurs in response to various stimuli, where the number or sensitivity of cell surface receptors or the expression of specific genes is decreased. This process helps maintain homeostasis within cells and tissues by reducing the ability of cells to respond to certain signals or molecules.

In the context of cell surface receptors, down-regulation can occur through several mechanisms:

1. Receptor internalization: After binding to their ligands, receptors can be internalized into the cell through endocytosis. Once inside the cell, these receptors may be degraded or recycled back to the cell surface in smaller numbers.
2. Reduced receptor synthesis: Down-regulation can also occur at the transcriptional level, where the expression of genes encoding for specific receptors is decreased, leading to fewer receptors being produced.
3. Receptor desensitization: Prolonged exposure to a ligand can lead to a decrease in receptor sensitivity or affinity, making it more difficult for the cell to respond to the signal.

In the context of gene expression, down-regulation refers to the decreased transcription and/or stability of specific mRNAs, leading to reduced protein levels. This process can be induced by various factors, including microRNA (miRNA)-mediated regulation, histone modification, or DNA methylation.

Down-regulation is an essential mechanism in many physiological processes and can also contribute to the development of several diseases, such as cancer and neurodegenerative disorders.

Mass spectrometry (MS) is an analytical technique used to identify and quantify the chemical components of a mixture or compound. It works by ionizing the sample, generating charged molecules or fragments, and then measuring their mass-to-charge ratio in a vacuum. The resulting mass spectrum provides information about the molecular weight and structure of the analytes, allowing for identification and characterization.

In simpler terms, mass spectrometry is a method used to determine what chemicals are present in a sample and in what quantities, by converting the chemicals into ions, measuring their masses, and generating a spectrum that shows the relative abundances of each ion type.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

In the context of nutrition and health, minerals are inorganic elements that are essential for various bodily functions, such as nerve impulse transmission, muscle contraction, maintaining fluid and electrolyte balance, and bone structure. They are required in small amounts compared to macronutrients (carbohydrates, proteins, and fats) and are obtained from food and water.

Some of the major minerals include calcium, phosphorus, magnesium, sodium, potassium, and chloride, while trace minerals or microminerals are required in even smaller amounts and include iron, zinc, copper, manganese, iodine, selenium, and fluoride.

It's worth noting that the term "minerals" can also refer to geological substances found in the earth, but in medical terminology, it specifically refers to the essential inorganic elements required for human health.

Santonin is not typically defined in the context of modern medicine, but it is a chemical compound that has been used historically in the treatment of intestinal parasites, specifically roundworm and pinworm infections. Santonin is derived from the dried seeds of the wormwood plant, Artemisia maritima or Artemisia santonicum.

It is important to note that the use of santonin as an antiparasitic agent has largely been replaced by safer and more effective medications. Santonin can cause side effects such as nausea, vomiting, diarrhea, dizziness, and seizures, particularly in high doses or with prolonged use. Its use is not recommended due to the availability of safer alternatives and potential health risks associated with its use.

Pseudohypoparathyroidism (PHP) is a rare genetic disorder characterized by the body's resistance to the action of parathyroid hormone (PTH), leading to hypocalcemia (low serum calcium levels) and hyperphosphatemia (high serum phosphate levels). Despite normal or elevated PTH levels, target organs such as the kidneys and bones do not respond appropriately to its actions.

There are several types of PHP, with the most common being type Ia, which is caused by mutations in the GNAS gene. This gene provides instructions for making a protein called the alpha-subunit of the stimulatory G protein (Gs-alpha), which plays a crucial role in transmitting signals within cells. In PHP type Ia, there is a reduced amount or functionally impaired Gs-alpha protein, leading to resistance to PTH and other hormones that use this signaling pathway, such as thyroid-stimulating hormone (TSH) and gonadotropins.

PHP type Ia patients often exhibit physical features known as Albright's hereditary osteodystrophy (AHO), including short stature, round face, obesity, brachydactyly (shortened fingers and toes), and ectopic ossifications (formation of bone in abnormal places). However, it is important to note that not all individuals with AHO have PHP, and not all PHP patients display AHO features.

PHP type Ib is another common form of the disorder, characterized by PTH resistance without the physical manifestations of AHO. This type is caused by mutations in the STX16 gene or other genes involved in the intracellular trafficking of Gs-alpha protein.

Pseudohypoparathyroidism should be differentiated from hypoparathyroidism, a condition where there is an insufficient production or secretion of PTH by the parathyroid glands, leading to similar biochemical abnormalities but without resistance to PTH action.

Phosphorus metabolism disorders refer to a group of conditions that affect the body's ability to properly regulate the levels and utilization of phosphorus. Phosphorus is an essential mineral that plays a critical role in many biological processes, including energy production, bone formation, and nerve function.

Disorders of phosphorus metabolism can result from genetic defects, kidney dysfunction, vitamin D deficiency, or other medical conditions. These disorders can lead to abnormal levels of phosphorus in the blood, which can cause a range of symptoms, including muscle weakness, bone pain, seizures, and respiratory failure.

Examples of phosphorus metabolism disorders include:

1. Hypophosphatemia: This is a condition characterized by low levels of phosphorus in the blood. It can be caused by various factors, such as malnutrition, vitamin D deficiency, and kidney dysfunction.
2. Hyperphosphatemia: This is a condition characterized by high levels of phosphorus in the blood. It can be caused by kidney failure, tumor lysis syndrome, and certain medications.
3. Hereditary hypophosphatemic rickets: This is a genetic disorder that affects the body's ability to regulate vitamin D and phosphorus metabolism. It can lead to weakened bones and skeletal deformities.
4. Oncogenic osteomalacia: This is a rare condition that occurs when tumors produce substances that interfere with phosphorus metabolism, leading to bone pain and weakness.

Treatment for phosphorus metabolism disorders depends on the underlying cause of the disorder and may include dietary changes, supplements, medications, or surgery.

Osteoprotegerin (OPG) is a soluble decoy receptor for the receptor activator of nuclear factor kappa-B ligand (RANKL). It is a member of the tumor necrosis factor (TNF) receptor superfamily and plays a crucial role in regulating bone metabolism. By binding to RANKL, OPG prevents it from interacting with its signaling receptor RANK on the surface of osteoclast precursor cells, thereby inhibiting osteoclast differentiation, activation, and survival. This results in reduced bone resorption and increased bone mass.

In addition to its role in bone homeostasis, OPG has also been implicated in various physiological and pathological processes, including immune regulation, cancer progression, and cardiovascular disease.

COS cells are a type of cell line that are commonly used in molecular biology and genetic research. The name "COS" is an acronym for "CV-1 in Origin," as these cells were originally derived from the African green monkey kidney cell line CV-1. COS cells have been modified through genetic engineering to express high levels of a protein called SV40 large T antigen, which allows them to efficiently take up and replicate exogenous DNA.

There are several different types of COS cells that are commonly used in research, including COS-1, COS-3, and COS-7 cells. These cells are widely used for the production of recombinant proteins, as well as for studies of gene expression, protein localization, and signal transduction.

It is important to note that while COS cells have been a valuable tool in scientific research, they are not without their limitations. For example, because they are derived from monkey kidney cells, there may be differences in the way that human genes are expressed or regulated in these cells compared to human cells. Additionally, because COS cells express SV40 large T antigen, they may have altered cell cycle regulation and other phenotypic changes that could affect experimental results. Therefore, it is important to carefully consider the choice of cell line when designing experiments and interpreting results.

Transcriptional activation is the process by which a cell increases the rate of transcription of specific genes from DNA to RNA. This process is tightly regulated and plays a crucial role in various biological processes, including development, differentiation, and response to environmental stimuli.

Transcriptional activation occurs when transcription factors (proteins that bind to specific DNA sequences) interact with the promoter region of a gene and recruit co-activator proteins. These co-activators help to remodel the chromatin structure around the gene, making it more accessible for the transcription machinery to bind and initiate transcription.

Transcriptional activation can be regulated at multiple levels, including the availability and activity of transcription factors, the modification of histone proteins, and the recruitment of co-activators or co-repressors. Dysregulation of transcriptional activation has been implicated in various diseases, including cancer and genetic disorders.

Alopecia is a medical term that refers to the loss of hair or baldness. It can occur in various parts of the body, but it's most commonly used to describe hair loss from the scalp. Alopecia can have several causes, including genetics, hormonal changes, medical conditions, and aging.

There are different types of alopecia, such as:

* Alopecia Areata: It is a condition that causes round patches of hair loss on the scalp or other parts of the body. The immune system attacks the hair follicles, causing the hair to fall out.
* Androgenetic Alopecia: Also known as male pattern baldness or female pattern baldness, it's a genetic condition that causes gradual hair thinning and eventual hair loss, typically following a specific pattern.
* Telogen Effluvium: It is a temporary hair loss condition caused by stress, medication, pregnancy, or other factors that can cause the hair follicles to enter a resting phase, leading to shedding and thinning of the hair.

The treatment for alopecia depends on the underlying cause. In some cases, such as with telogen effluvium, hair growth may resume without any treatment. However, other forms of alopecia may require medical intervention, including topical treatments, oral medications, or even hair transplant surgery in severe cases.

Dehydrocholesterols are a type of sterol that is derived from cholesterol through the process of oxidation and the removal of hydrogen atoms. These compounds are important intermediates in the biosynthesis of vitamin D and other steroid hormones in the body.

The most well-known dehydrocholesterol is 7-dehydrocholesterol, which is converted to vitamin D3 (cholecalciferol) through a reaction that involves exposure to ultraviolet B (UVB) radiation from sunlight. This conversion occurs in the skin and is an essential step in the production of vitamin D, which plays a critical role in maintaining healthy bones, teeth, and immune function.

Other dehydrocholesterols include 4-en-3-oxo-5α-cholest-8(14)-en-3β-ol (also known as Δ4-dehydrocholesterol) and 5,7,22,24-tetrahydroxycholesterol, which are also important intermediates in the biosynthesis of steroid hormones.

It is worth noting that dehydrocholesterols can be oxidized further to form other compounds known as oxysterols, which have been implicated in various disease processes such as atherosclerosis and neurodegeneration.

Mesenchymoma is a very rare type of tumor that contains a mixture of different types of mesenchymal tissues, such as muscle, fat, bone, cartilage, or fibrous tissue. It typically occurs in children and young adults, and can be found in various parts of the body, including the head, neck, retroperitoneum (the area behind the abdominal cavity), and the limbs.

Mesenchymomas are usually slow-growing and may not cause any symptoms until they reach a large size. Treatment typically involves surgical removal of the tumor, but radiation therapy or chemotherapy may also be used in some cases. The prognosis for mesenchymoma depends on several factors, including the location and size of the tumor, the patient's age and overall health, and the specific types of tissue that are present in the tumor.

The skull is the bony structure that encloses and protects the brain, the eyes, and the ears. It is composed of two main parts: the cranium, which contains the brain, and the facial bones. The cranium is made up of several fused flat bones, while the facial bones include the upper jaw (maxilla), lower jaw (mandible), cheekbones, nose bones, and eye sockets (orbits).

The skull also provides attachment points for various muscles that control chewing, moving the head, and facial expressions. Additionally, it contains openings for blood vessels, nerves, and the spinal cord to pass through. The skull's primary function is to protect the delicate and vital structures within it from injury and trauma.

Apolipoprotein D (apoD) is a protein that is associated with high-density lipoprotein (HDL) particles in the blood. It is one of several apolipoproteins that are involved in the transport and metabolism of lipids, such as cholesterol and triglycerides, in the body.

ApoD is produced by the APOD gene and is found in various tissues, including the brain, where it is believed to play a role in protecting nerve cells from oxidative stress. It has also been studied for its potential role in Alzheimer's disease and other neurological disorders.

In addition to its role in lipid metabolism and neuroprotection, apoD has been shown to have anti-inflammatory properties and may be involved in the regulation of immune responses. However, more research is needed to fully understand the functions and mechanisms of action of this protein.

Neoplastic gene expression regulation refers to the processes that control the production of proteins and other molecules from genes in neoplastic cells, or cells that are part of a tumor or cancer. In a normal cell, gene expression is tightly regulated to ensure that the right genes are turned on or off at the right time. However, in cancer cells, this regulation can be disrupted, leading to the overexpression or underexpression of certain genes.

Neoplastic gene expression regulation can be affected by a variety of factors, including genetic mutations, epigenetic changes, and signals from the tumor microenvironment. These changes can lead to the activation of oncogenes (genes that promote cancer growth and development) or the inactivation of tumor suppressor genes (genes that prevent cancer).

Understanding neoplastic gene expression regulation is important for developing new therapies for cancer, as targeting specific genes or pathways involved in this process can help to inhibit cancer growth and progression.

CD14 is a type of protein found on the surface of certain cells in the human body, including monocytes, macrophages, and some types of dendritic cells. These cells are part of the immune system and play a crucial role in detecting and responding to infections and other threats.

CD14 is not an antigen itself, but it can bind to certain types of antigens, such as lipopolysaccharides (LPS) found on the surface of gram-negative bacteria. When CD14 binds to an LPS molecule, it helps to activate the immune response and trigger the production of cytokines and other inflammatory mediators.

CD14 can also be found in soluble form in the bloodstream, where it can help to neutralize LPS and prevent it from causing damage to tissues and organs.

It's worth noting that while CD14 plays an important role in the immune response, it is not typically used as a target for vaccines or other immunotherapies. Instead, it is often studied as a marker of immune activation and inflammation in various diseases, including sepsis, atherosclerosis, and Alzheimer's disease.

Receptor Activator of Nuclear Factor-kappa B (RANK) is a type I transmembrane protein and a member of the tumor necrosis factor receptor superfamily. It plays a crucial role in the regulation of bone metabolism through the activation of osteoclasts, which are cells responsible for bone resorption.

When RANK binds to its ligand, RANKL (Receptor Activator of Nuclear Factor-kappa B Ligand), it triggers a series of intracellular signaling events that lead to the activation and differentiation of osteoclast precursors into mature osteoclasts. This process is essential for maintaining bone homeostasis, as excessive osteoclast activity can result in bone loss and diseases such as osteoporosis.

In addition to its role in bone metabolism, RANK has also been implicated in the regulation of immune responses, as it is involved in the activation and differentiation of dendritic cells and T cells. Dysregulation of RANK signaling has been associated with various pathological conditions, including autoimmune diseases and cancer.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Hyperparathyroidism is a condition in which the parathyroid glands produce excessive amounts of parathyroid hormone (PTH). There are four small parathyroid glands located in the neck, near or within the thyroid gland. They release PTH into the bloodstream to help regulate the levels of calcium and phosphorus in the body.

In hyperparathyroidism, overproduction of PTH can lead to an imbalance in these minerals, causing high blood calcium levels (hypercalcemia) and low phosphate levels (hypophosphatemia). This can result in various symptoms such as fatigue, weakness, bone pain, kidney stones, and cognitive issues.

There are two types of hyperparathyroidism: primary and secondary. Primary hyperparathyroidism occurs when there is a problem with one or more of the parathyroid glands, causing them to become overactive and produce too much PTH. Secondary hyperparathyroidism develops as a response to low calcium levels in the body due to conditions like vitamin D deficiency, chronic kidney disease, or malabsorption syndromes.

Treatment for hyperparathyroidism depends on the underlying cause and severity of symptoms. In primary hyperparathyroidism, surgery to remove the overactive parathyroid gland(s) is often recommended. For secondary hyperparathyroidism, treating the underlying condition and managing calcium levels with medications or dietary changes may be sufficient.

Betamethasone valerate is a synthetic corticosteroid drug, which is a derivative of betamethasone. It is used as a topical preparation for the treatment of various skin conditions such as eczema, psoriasis, and dermatitis. The valerate ester of betamethasone provides a sustained release of the active steroid, allowing for less frequent application and improved penetration into the skin.

Betamethasone valerate works by reducing inflammation, suppressing the immune system, and relieving itching and redness in the affected area. It is available in various forms, including creams, ointments, and lotions, and should be used under the direction of a healthcare professional to ensure proper use and minimize potential side effects.

Like other corticosteroids, betamethasone valerate can cause thinning of the skin, increased hair growth, and acne with prolonged or excessive use. It is important to follow the recommended dosage and duration of treatment to avoid these side effects.

Calcium-sensing receptors (CaSR) are a type of G protein-coupled receptor that play a crucial role in the regulation of extracellular calcium homeostasis. They are widely expressed in various tissues, including the parathyroid gland, kidney, and bone.

The primary function of CaSR is to detect changes in extracellular calcium concentrations and transmit signals to regulate the release of parathyroid hormone (PTH) from the parathyroid gland. When the concentration of extracellular calcium increases, CaSR is activated, which leads to a decrease in PTH secretion, thereby preventing further elevation of calcium levels. Conversely, when calcium levels decrease, CaSR is inhibited, leading to an increase in PTH release and restoration of normal calcium levels.

In addition to regulating calcium homeostasis, CaSR also plays a role in other physiological processes, including cell proliferation, differentiation, and apoptosis. Dysregulation of CaSR has been implicated in various diseases, such as hyperparathyroidism, hypoparathyroidism, and cancer. Therefore, understanding the function and regulation of CaSR is essential for developing new therapeutic strategies to treat these conditions.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

Bone density refers to the amount of bone mineral content (usually measured in grams) in a given volume of bone (usually measured in cubic centimeters). It is often used as an indicator of bone strength and fracture risk. Bone density is typically measured using dual-energy X-ray absorptiometry (DXA) scans, which provide a T-score that compares the patient's bone density to that of a young adult reference population. A T-score of -1 or above is considered normal, while a T-score between -1 and -2.5 indicates osteopenia (low bone mass), and a T-score below -2.5 indicates osteoporosis (porous bones). Regular exercise, adequate calcium and vitamin D intake, and medication (if necessary) can help maintain or improve bone density and prevent fractures.

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

Breast neoplasms refer to abnormal growths in the breast tissue that can be benign or malignant. Benign breast neoplasms are non-cancerous tumors or growths, while malignant breast neoplasms are cancerous tumors that can invade surrounding tissues and spread to other parts of the body.

Breast neoplasms can arise from different types of cells in the breast, including milk ducts, milk sacs (lobules), or connective tissue. The most common type of breast cancer is ductal carcinoma, which starts in the milk ducts and can spread to other parts of the breast and nearby structures.

Breast neoplasms are usually detected through screening methods such as mammography, ultrasound, or MRI, or through self-examination or clinical examination. Treatment options for breast neoplasms depend on several factors, including the type and stage of the tumor, the patient's age and overall health, and personal preferences. Treatment may include surgery, radiation therapy, chemotherapy, hormone therapy, or targeted therapy.

Bone marrow cells are the types of cells found within the bone marrow, which is the spongy tissue inside certain bones in the body. The main function of bone marrow is to produce blood cells. There are two types of bone marrow: red and yellow. Red bone marrow is where most blood cell production takes place, while yellow bone marrow serves as a fat storage site.

The three main types of bone marrow cells are:

1. Hematopoietic stem cells (HSCs): These are immature cells that can differentiate into any type of blood cell, including red blood cells, white blood cells, and platelets. They have the ability to self-renew, meaning they can divide and create more hematopoietic stem cells.
2. Red blood cell progenitors: These are immature cells that will develop into mature red blood cells, also known as erythrocytes. Red blood cells carry oxygen from the lungs to the body's tissues and carbon dioxide back to the lungs.
3. Myeloid and lymphoid white blood cell progenitors: These are immature cells that will develop into various types of white blood cells, which play a crucial role in the body's immune system by fighting infections and diseases. Myeloid progenitors give rise to granulocytes (neutrophils, eosinophils, and basophils), monocytes, and megakaryocytes (which eventually become platelets). Lymphoid progenitors differentiate into B cells, T cells, and natural killer (NK) cells.

Bone marrow cells are essential for maintaining a healthy blood cell count and immune system function. Abnormalities in bone marrow cells can lead to various medical conditions, such as anemia, leukopenia, leukocytosis, thrombocytopenia, or thrombocytosis, depending on the specific type of blood cell affected. Additionally, bone marrow cells are often used in transplantation procedures to treat patients with certain types of cancer, such as leukemia and lymphoma, or other hematologic disorders.

Endothelin-3 (ET-3) is a member of the endothelin family, which are small peptides with potent vasoconstrictor properties. ET-3 is primarily produced by neurons in the central and peripheral nervous system, and it plays important roles in the development and regulation of various physiological functions, including cardiovascular function, neurotransmission, and cell proliferation.

ET-3 exerts its effects by binding to specific G protein-coupled receptors, known as endothelin A (ETA) and endothelin B (ETB) receptors. These receptors are widely distributed throughout the body, including in the cardiovascular, respiratory, gastrointestinal, and genitourinary systems.

In addition to its role as a potent vasoconstrictor, ET-3 has been implicated in various pathological conditions, such as hypertension, heart failure, pulmonary arterial hypertension, and cancer. In recent years, there has been growing interest in the potential therapeutic use of endothelin receptor antagonists to treat these conditions.

Colonic neoplasms refer to abnormal growths in the large intestine, also known as the colon. These growths can be benign (non-cancerous) or malignant (cancerous). The two most common types of colonic neoplasms are adenomas and carcinomas.

Adenomas are benign tumors that can develop into cancer over time if left untreated. They are often found during routine colonoscopies and can be removed during the procedure.

Carcinomas, on the other hand, are malignant tumors that invade surrounding tissues and can spread to other parts of the body. Colorectal cancer is the third leading cause of cancer-related deaths in the United States, and colonic neoplasms are a significant risk factor for developing this type of cancer.

Regular screenings for colonic neoplasms are recommended for individuals over the age of 50 or those with a family history of colorectal cancer or other risk factors. Early detection and removal of colonic neoplasms can significantly reduce the risk of developing colorectal cancer.

Apoptosis is a programmed and controlled cell death process that occurs in multicellular organisms. It is a natural process that helps maintain tissue homeostasis by eliminating damaged, infected, or unwanted cells. During apoptosis, the cell undergoes a series of morphological changes, including cell shrinkage, chromatin condensation, and fragmentation into membrane-bound vesicles called apoptotic bodies. These bodies are then recognized and engulfed by neighboring cells or phagocytic cells, preventing an inflammatory response. Apoptosis is regulated by a complex network of intracellular signaling pathways that involve proteins such as caspases, Bcl-2 family members, and inhibitors of apoptosis (IAPs).

The cell cycle is a series of events that take place in a cell leading to its division and duplication. It consists of four main phases: G1 phase, S phase, G2 phase, and M phase.

During the G1 phase, the cell grows in size and synthesizes mRNA and proteins in preparation for DNA replication. In the S phase, the cell's DNA is copied, resulting in two complete sets of chromosomes. During the G2 phase, the cell continues to grow and produces more proteins and organelles necessary for cell division.

The M phase is the final stage of the cell cycle and consists of mitosis (nuclear division) and cytokinesis (cytoplasmic division). Mitosis results in two genetically identical daughter nuclei, while cytokinesis divides the cytoplasm and creates two separate daughter cells.

The cell cycle is regulated by various checkpoints that ensure the proper completion of each phase before progressing to the next. These checkpoints help prevent errors in DNA replication and division, which can lead to mutations and cancer.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

The epidermis is the outermost layer of the skin, composed mainly of stratified squamous epithelium. It forms a protective barrier that prevents water loss and inhibits the entry of microorganisms. The epidermis contains no blood vessels, and its cells are nourished by diffusion from the underlying dermis. The bottom-most layer of the epidermis, called the stratum basale, is responsible for generating new skin cells that eventually move up to replace dead cells on the surface. This process of cell turnover takes about 28 days in adults.

The most superficial part of the epidermis consists of dead cells called squames, which are constantly shed and replaced. The exact rate at which this happens varies depending on location; for example, it's faster on the palms and soles than elsewhere. Melanocytes, the pigment-producing cells, are also located in the epidermis, specifically within the stratum basale layer.

In summary, the epidermis is a vital part of our integumentary system, providing not only physical protection but also playing a crucial role in immunity and sensory perception through touch receptors called Pacinian corpuscles.

Granulocytes are a type of white blood cell that plays a crucial role in the body's immune system. They are called granulocytes because they contain small granules in their cytoplasm, which are filled with various enzymes and proteins that help them fight off infections and destroy foreign substances.

There are three types of granulocytes: neutrophils, eosinophils, and basophils. Neutrophils are the most abundant type and are primarily responsible for fighting bacterial infections. Eosinophils play a role in defending against parasitic infections and regulating immune responses. Basophils are involved in inflammatory reactions and allergic responses.

Granulocytes are produced in the bone marrow and released into the bloodstream, where they circulate and patrol for any signs of infection or foreign substances. When they encounter a threat, they quickly move to the site of infection or injury and release their granules to destroy the invading organisms or substances.

Abnormal levels of granulocytes in the blood can indicate an underlying medical condition, such as an infection, inflammation, or a bone marrow disorder.

In medicine, "absorption" refers to the process by which substances, including nutrients, medications, or toxins, are taken up and assimilated into the body's tissues or bloodstream after they have been introduced into the body via various routes (such as oral, intravenous, or transdermal).

The absorption of a substance depends on several factors, including its chemical properties, the route of administration, and the presence of other substances that may affect its uptake. For example, some medications may be better absorbed when taken with food, while others may require an empty stomach for optimal absorption.

Once a substance is absorbed into the bloodstream, it can then be distributed to various tissues throughout the body, where it may exert its effects or be metabolized and eliminated by the body's detoxification systems. Understanding the process of absorption is crucial in developing effective medical treatments and determining appropriate dosages for medications.

Arylsulfatases are a group of enzymes that play a role in the breakdown and recycling of complex molecules in the body. Specifically, they catalyze the hydrolysis of sulfate ester bonds in certain types of large sugar molecules called glycosaminoglycans (GAGs).

There are several different types of arylsulfatases, each of which targets a specific type of sulfate ester bond. For example, arylsulfatase A is responsible for breaking down sulfate esters in a GAG called cerebroside sulfate, while arylsulfatase B targets a different GAG called dermatan sulfate.

Deficiencies in certain arylsulfatases can lead to genetic disorders. For example, a deficiency in arylsulfatase A can cause metachromatic leukodystrophy, a progressive neurological disorder that affects the nervous system and causes a range of symptoms including muscle weakness, developmental delays, and cognitive decline. Similarly, a deficiency in arylsulfatase B can lead to Maroteaux-Lamy syndrome, a rare genetic disorder that affects the skeleton, eyes, ears, heart, and other organs.

Paraneoplastic syndromes refer to a group of rare disorders that are caused by an abnormal immune system response to a cancerous (malignant) tumor. These syndromes are characterized by symptoms or signs that do not result directly from the growth of the tumor itself, but rather from substances produced by the tumor or the body's immune system in response to the tumor.

Paraneoplastic syndromes can affect various organs and systems in the body, including the nervous system, endocrine system, skin, and joints. Examples of paraneoplastic syndromes include Lambert-Eaton myasthenic syndrome (LEMS), which affects nerve function and causes muscle weakness; cerebellar degeneration, which can cause difficulty with coordination and balance; and dermatomyositis, which is an inflammatory condition that affects the skin and muscles.

Paraneoplastic syndromes can occur in association with a variety of different types of cancer, including lung cancer, breast cancer, ovarian cancer, and lymphoma. Treatment typically involves addressing the underlying cancer, as well as managing the symptoms of the paraneoplastic syndrome.

Gene expression regulation in leukemia refers to the processes that control the production or activation of specific proteins encoded by genes in leukemic cells. These regulatory mechanisms include various molecular interactions that can either promote or inhibit gene transcription and translation. In leukemia, abnormal gene expression regulation can lead to uncontrolled proliferation, differentiation arrest, and accumulation of malignant white blood cells (leukemia cells) in the bone marrow and peripheral blood.

Dysregulated gene expression in leukemia may involve genetic alterations such as mutations, chromosomal translocations, or epigenetic changes that affect DNA methylation patterns and histone modifications. These changes can result in the overexpression of oncogenes (genes with cancer-promoting functions) or underexpression of tumor suppressor genes (genes that prevent uncontrolled cell growth).

Understanding gene expression regulation in leukemia is crucial for developing targeted therapies and improving diagnostic, prognostic, and treatment strategies.

A "cell line, transformed" is a type of cell culture that has undergone a stable genetic alteration, which confers the ability to grow indefinitely in vitro, outside of the organism from which it was derived. These cells have typically been immortalized through exposure to chemical or viral carcinogens, or by introducing specific oncogenes that disrupt normal cell growth regulation pathways.

Transformed cell lines are widely used in scientific research because they offer a consistent and renewable source of biological material for experimentation. They can be used to study various aspects of cell biology, including signal transduction, gene expression, drug discovery, and toxicity testing. However, it is important to note that transformed cells may not always behave identically to their normal counterparts, and results obtained using these cells should be validated in more physiologically relevant systems when possible.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

DNA-binding proteins are a type of protein that have the ability to bind to DNA (deoxyribonucleic acid), the genetic material of organisms. These proteins play crucial roles in various biological processes, such as regulation of gene expression, DNA replication, repair and recombination.

The binding of DNA-binding proteins to specific DNA sequences is mediated by non-covalent interactions, including electrostatic, hydrogen bonding, and van der Waals forces. The specificity of binding is determined by the recognition of particular nucleotide sequences or structural features of the DNA molecule.

DNA-binding proteins can be classified into several categories based on their structure and function, such as transcription factors, histones, and restriction enzymes. Transcription factors are a major class of DNA-binding proteins that regulate gene expression by binding to specific DNA sequences in the promoter region of genes and recruiting other proteins to modulate transcription. Histones are DNA-binding proteins that package DNA into nucleosomes, the basic unit of chromatin structure. Restriction enzymes are DNA-binding proteins that recognize and cleave specific DNA sequences, and are widely used in molecular biology research and biotechnology applications.

Vitamin K is a fat-soluble vitamin that plays a crucial role in blood clotting and bone metabolism. It is essential for the production of several proteins involved in blood clotting, including factor II (prothrombin), factor VII, factor IX, and factor X. Additionally, Vitamin K is necessary for the synthesis of osteocalcin, a protein that contributes to bone health by regulating the deposition of calcium in bones.

There are two main forms of Vitamin K: Vitamin K1 (phylloquinone), which is found primarily in green leafy vegetables and some vegetable oils, and Vitamin K2 (menaquinones), which is produced by bacteria in the intestines and is also found in some fermented foods.

Vitamin K deficiency can lead to bleeding disorders such as hemorrhage and excessive bruising. While Vitamin K deficiency is rare in adults, it can occur in newborns who have not yet developed sufficient levels of the vitamin. Therefore, newborns are often given a Vitamin K injection shortly after birth to prevent bleeding problems.

Acute Monocytic Leukemia (AML-M5) is a subtype of acute myeloid leukemia (AML), which is a type of cancer affecting the blood and bone marrow. In AML-M5, there is an overproduction of abnormal monocytes, a type of white blood cell that normally helps fight infection and is involved in the body's immune response. These abnormal monocytes accumulate in the bone marrow and interfere with the production of normal blood cells, leading to symptoms such as fatigue, frequent infections, and easy bruising or bleeding. The disease progresses rapidly without treatment, making it crucial to begin therapy as soon as possible after diagnosis.

Acid phosphatase is a type of enzyme that is found in various tissues and organs throughout the body, including the prostate gland, red blood cells, bone, liver, spleen, and kidneys. This enzyme plays a role in several biological processes, such as bone metabolism and the breakdown of molecules like nucleotides and proteins.

Acid phosphatase is classified based on its optimum pH level for activity. Acid phosphatases have an optimal activity at acidic pH levels (below 7.0), while alkaline phosphatases have an optimal activity at basic or alkaline pH levels (above 7.0).

In clinical settings, measuring the level of acid phosphatase in the blood can be useful as a tumor marker for prostate cancer. Elevated acid phosphatase levels may indicate the presence of metastatic prostate cancer or disease progression. However, it is important to note that acid phosphatase is not specific to prostate cancer and can also be elevated in other conditions, such as bone diseases, liver disorders, and some benign conditions. Therefore, acid phosphatase should be interpreted in conjunction with other diagnostic tests and clinical findings for a more accurate diagnosis.

Tritium is not a medical term, but it is a term used in the field of nuclear physics and chemistry. Tritium (symbol: T or 3H) is a radioactive isotope of hydrogen with two neutrons and one proton in its nucleus. It is also known as heavy hydrogen or superheavy hydrogen.

Tritium has a half-life of about 12.3 years, which means that it decays by emitting a low-energy beta particle (an electron) to become helium-3. Due to its radioactive nature and relatively short half-life, tritium is used in various applications, including nuclear weapons, fusion reactors, luminous paints, and medical research.

In the context of medicine, tritium may be used as a radioactive tracer in some scientific studies or medical research, but it is not a term commonly used to describe a medical condition or treatment.

Bone density conservation agents, also known as anti-resorptive agents or bone-sparing drugs, are a class of medications that help to prevent the loss of bone mass and reduce the risk of fractures. They work by inhibiting the activity of osteoclasts, the cells responsible for breaking down and reabsorbing bone tissue during the natural remodeling process.

Examples of bone density conservation agents include:

1. Bisphosphonates (e.g., alendronate, risedronate, ibandronate, zoledronic acid) - These are the most commonly prescribed class of bone density conservation agents. They bind to hydroxyapatite crystals in bone tissue and inhibit osteoclast activity, thereby reducing bone resorption.
2. Denosumab (Prolia) - This is a monoclonal antibody that targets RANKL (Receptor Activator of Nuclear Factor-κB Ligand), a key signaling molecule involved in osteoclast differentiation and activation. By inhibiting RANKL, denosumab reduces osteoclast activity and bone resorption.
3. Selective estrogen receptor modulators (SERMs) (e.g., raloxifene) - These medications act as estrogen agonists or antagonists in different tissues. In bone tissue, SERMs mimic the bone-preserving effects of estrogen by inhibiting osteoclast activity and reducing bone resorption.
4. Hormone replacement therapy (HRT) - Estrogen hormone replacement therapy has been shown to preserve bone density in postmenopausal women; however, its use is limited due to increased risks of breast cancer, cardiovascular disease, and thromboembolic events.
5. Calcitonin - This hormone, secreted by the thyroid gland, inhibits osteoclast activity and reduces bone resorption. However, it has largely been replaced by other more effective bone density conservation agents.

These medications are often prescribed for individuals at high risk of fractures due to conditions such as osteoporosis or metabolic disorders that affect bone health. It is essential to follow the recommended dosage and administration guidelines to maximize their benefits while minimizing potential side effects. Regular monitoring of bone density, blood calcium levels, and other relevant parameters is also necessary during treatment with these medications.

Trimethylsilyl compounds are organosilicon substances that contain the functional group Si(CH3)3-, known as a trimethylsilyl group. These compounds are widely used in various fields, including chemistry and biochemistry, as reagents, protecting groups, or derivatizing agents.

In a medical context, trimethylsilyl compounds may be encountered in the analysis of biological samples, such as blood, urine, or tissues, using techniques like gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS). These methods often require the derivatization of polar or labile compounds to increase their volatility and thermal stability. Trimethylsilylating agents, such as trimethylsilyl chloride (TMSCl) or N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), are commonly used to convert polar functional groups like hydroxyl (-OH), amino (-NH2), or carboxyl (-COOH) into their corresponding trimethylsilyl ethers, esters, or amides. This derivatization process facilitates the separation and detection of these compounds in complex biological matrices.

It is important to note that direct exposure to some trimethylsilyl compounds may cause irritation to the skin, eyes, and respiratory tract; therefore, appropriate safety measures should be taken when handling these substances.

Fat substitutes are substances that are used in food production to mimic the taste, texture, and other sensory properties of fat, while providing fewer calories or no calories at all. They can be derived from natural sources, such as carbohydrates or proteins, or synthesized in a lab.

Fat substitutes can be classified into three main categories:

1. Macronutrient-based fat substitutes: These are made up of carbohydrates, proteins, or fiber that provide fewer calories than fat. Examples include maltodextrin, modified food starch, and whey protein concentrate.
2. Fat-based fat substitutes: These are made up of fat molecules that have been chemically altered to reduce their calorie content. Examples include olestra (sucrose polyester) and caprenin.
3. Non-nutritive fat substitutes: These provide no calories or nutrients and are often used in small amounts to enhance the texture and taste of food. Examples include cellulose gel, microcrystalline cellulose, and silica.

Fat substitutes can be useful for people who are trying to reduce their calorie intake, maintain a healthy weight, or manage certain medical conditions such as diabetes or high cholesterol. However, it's important to note that fat substitutes should not replace all dietary fats, as some fats are essential for good health. It's also important to read food labels carefully and consume fat substitutes in moderation, as they may have other negative effects on health if consumed in excess.

Stereoisomerism is a type of isomerism (structural arrangement of atoms) in which molecules have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientation of their atoms in space. This occurs when the molecule contains asymmetric carbon atoms or other rigid structures that prevent free rotation, leading to distinct spatial arrangements of groups of atoms around a central point. Stereoisomers can have different chemical and physical properties, such as optical activity, boiling points, and reactivities, due to differences in their shape and the way they interact with other molecules.

There are two main types of stereoisomerism: enantiomers (mirror-image isomers) and diastereomers (non-mirror-image isomers). Enantiomers are pairs of stereoisomers that are mirror images of each other, but cannot be superimposed on one another. Diastereomers, on the other hand, are non-mirror-image stereoisomers that have different physical and chemical properties.

Stereoisomerism is an important concept in chemistry and biology, as it can affect the biological activity of molecules, such as drugs and natural products. For example, some enantiomers of a drug may be active, while others are inactive or even toxic. Therefore, understanding stereoisomerism is crucial for designing and synthesizing effective and safe drugs.

Interferon-gamma (IFN-γ) is a soluble cytokine that is primarily produced by the activation of natural killer (NK) cells and T lymphocytes, especially CD4+ Th1 cells and CD8+ cytotoxic T cells. It plays a crucial role in the regulation of the immune response against viral and intracellular bacterial infections, as well as tumor cells. IFN-γ has several functions, including activating macrophages to enhance their microbicidal activity, increasing the presentation of major histocompatibility complex (MHC) class I and II molecules on antigen-presenting cells, stimulating the proliferation and differentiation of T cells and NK cells, and inducing the production of other cytokines and chemokines. Additionally, IFN-γ has direct antiproliferative effects on certain types of tumor cells and can enhance the cytotoxic activity of immune cells against infected or malignant cells.

Isoenzymes, also known as isoforms, are multiple forms of an enzyme that catalyze the same chemical reaction but differ in their amino acid sequence, structure, and/or kinetic properties. They are encoded by different genes or alternative splicing of the same gene. Isoenzymes can be found in various tissues and organs, and they play a crucial role in biological processes such as metabolism, detoxification, and cell signaling. Measurement of isoenzyme levels in body fluids (such as blood) can provide valuable diagnostic information for certain medical conditions, including tissue damage, inflammation, and various diseases.

A biological assay is a method used in biology and biochemistry to measure the concentration or potency of a substance (like a drug, hormone, or enzyme) by observing its effect on living cells or tissues. This type of assay can be performed using various techniques such as:

1. Cell-based assays: These involve measuring changes in cell behavior, growth, or viability after exposure to the substance being tested. Examples include proliferation assays, apoptosis assays, and cytotoxicity assays.
2. Protein-based assays: These focus on measuring the interaction between the substance and specific proteins, such as enzymes or receptors. Examples include enzyme-linked immunosorbent assays (ELISAs), radioimmunoassays (RIAs), and pull-down assays.
3. Genetic-based assays: These involve analyzing the effects of the substance on gene expression, DNA structure, or protein synthesis. Examples include quantitative polymerase chain reaction (qPCR) assays, reporter gene assays, and northern blotting.

Biological assays are essential tools in research, drug development, and diagnostic applications to understand biological processes and evaluate the potential therapeutic efficacy or toxicity of various substances.

Protein Kinase C (PKC) is a family of serine-threonine kinases that play crucial roles in various cellular signaling pathways. These enzymes are activated by second messengers such as diacylglycerol (DAG) and calcium ions (Ca2+), which result from the activation of cell surface receptors like G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs).

Once activated, PKC proteins phosphorylate downstream target proteins, thereby modulating their activities. This regulation is involved in numerous cellular processes, including cell growth, differentiation, apoptosis, and membrane trafficking. There are at least 10 isoforms of PKC, classified into three subfamilies based on their second messenger requirements and structural features: conventional (cPKC; α, βI, βII, and γ), novel (nPKC; δ, ε, η, and θ), and atypical (aPKC; ζ and ι/λ). Dysregulation of PKC signaling has been implicated in several diseases, such as cancer, diabetes, and neurological disorders.

A diet, in medical terms, refers to the planned and regular consumption of food and drinks. It is a balanced selection of nutrient-rich foods that an individual eats on a daily or periodic basis to meet their energy needs and maintain good health. A well-balanced diet typically includes a variety of fruits, vegetables, whole grains, lean proteins, and low-fat dairy products.

A diet may also be prescribed for therapeutic purposes, such as in the management of certain medical conditions like diabetes, hypertension, or obesity. In these cases, a healthcare professional may recommend specific restrictions or modifications to an individual's regular diet to help manage their condition and improve their overall health.

It is important to note that a healthy and balanced diet should be tailored to an individual's age, gender, body size, activity level, and any underlying medical conditions. Consulting with a healthcare professional, such as a registered dietitian or nutritionist, can help ensure that an individual's dietary needs are being met in a safe and effective way.

A biological marker, often referred to as a biomarker, is a measurable indicator that reflects the presence or severity of a disease state, or a response to a therapeutic intervention. Biomarkers can be found in various materials such as blood, tissues, or bodily fluids, and they can take many forms, including molecular, histologic, radiographic, or physiological measurements.

In the context of medical research and clinical practice, biomarkers are used for a variety of purposes, such as:

1. Diagnosis: Biomarkers can help diagnose a disease by indicating the presence or absence of a particular condition. For example, prostate-specific antigen (PSA) is a biomarker used to detect prostate cancer.
2. Monitoring: Biomarkers can be used to monitor the progression or regression of a disease over time. For instance, hemoglobin A1c (HbA1c) levels are monitored in diabetes patients to assess long-term blood glucose control.
3. Predicting: Biomarkers can help predict the likelihood of developing a particular disease or the risk of a negative outcome. For example, the presence of certain genetic mutations can indicate an increased risk for breast cancer.
4. Response to treatment: Biomarkers can be used to evaluate the effectiveness of a specific treatment by measuring changes in the biomarker levels before and after the intervention. This is particularly useful in personalized medicine, where treatments are tailored to individual patients based on their unique biomarker profiles.

It's important to note that for a biomarker to be considered clinically valid and useful, it must undergo rigorous validation through well-designed studies, including demonstrating sensitivity, specificity, reproducibility, and clinical relevance.

Bone diseases is a broad term that refers to various medical conditions that affect the bones. These conditions can be categorized into several groups, including:

1. Developmental and congenital bone diseases: These are conditions that affect bone growth and development before or at birth. Examples include osteogenesis imperfecta (brittle bone disease), achondroplasia (dwarfism), and cleidocranial dysostosis.
2. Metabolic bone diseases: These are conditions that affect the body's ability to maintain healthy bones. They are often caused by hormonal imbalances, vitamin deficiencies, or problems with mineral metabolism. Examples include osteoporosis, osteomalacia, and Paget's disease of bone.
3. Inflammatory bone diseases: These are conditions that cause inflammation in the bones. They can be caused by infections, autoimmune disorders, or other medical conditions. Examples include osteomyelitis, rheumatoid arthritis, and ankylosing spondylitis.
4. Degenerative bone diseases: These are conditions that cause the bones to break down over time. They can be caused by aging, injury, or disease. Examples include osteoarthritis, avascular necrosis, and diffuse idiopathic skeletal hyperostosis (DISH).
5. Tumors and cancers of the bone: These are conditions that involve abnormal growths in the bones. They can be benign or malignant. Examples include osteosarcoma, chondrosarcoma, and Ewing sarcoma.
6. Fractures and injuries: While not strictly a "disease," fractures and injuries are common conditions that affect the bones. They can result from trauma, overuse, or weakened bones. Examples include stress fractures, compound fractures, and dislocations.

Overall, bone diseases can cause a wide range of symptoms, including pain, stiffness, deformity, and decreased mobility. Treatment for these conditions varies depending on the specific diagnosis but may include medication, surgery, physical therapy, or lifestyle changes.

Calcium channels are specialized proteins that span the membrane of cells and allow calcium ions (Ca²+) to flow in and out of the cell. They are crucial for many physiological processes, including muscle contraction, neurotransmitter release, hormone secretion, and gene expression.

There are several types of calcium channels, classified based on their biophysical and pharmacological properties. The most well-known are:

1. Voltage-gated calcium channels (VGCCs): These channels are activated by changes in the membrane potential. They are further divided into several subtypes, including L-type, P/Q-type, N-type, R-type, and T-type. VGCCs play a critical role in excitation-contraction coupling in muscle cells and neurotransmitter release in neurons.
2. Receptor-operated calcium channels (ROCCs): These channels are activated by the binding of an extracellular ligand, such as a hormone or neurotransmitter, to a specific receptor on the cell surface. ROCCs are involved in various physiological processes, including smooth muscle contraction and platelet activation.
3. Store-operated calcium channels (SOCCs): These channels are activated by the depletion of intracellular calcium stores, such as those found in the endoplasmic reticulum. SOCCs play a critical role in maintaining calcium homeostasis and signaling within cells.

Dysregulation of calcium channel function has been implicated in various diseases, including hypertension, arrhythmias, migraine, epilepsy, and neurodegenerative disorders. Therefore, calcium channels are an important target for drug development and therapy.

Chloramphenicol O-acetyltransferase is an enzyme that is encoded by the cat gene in certain bacteria. This enzyme is responsible for adding acetyl groups to chloramphenicol, which is an antibiotic that inhibits bacterial protein synthesis. When chloramphenicol is acetylated by this enzyme, it becomes inactivated and can no longer bind to the ribosome and prevent bacterial protein synthesis.

Bacteria that are resistant to chloramphenicol often have a plasmid-borne cat gene, which encodes for the production of Chloramphenicol O-acetyltransferase. This enzyme allows the bacteria to survive in the presence of chloramphenicol by rendering it ineffective. The transfer of this plasmid between bacteria can also confer resistance to other susceptible strains.

In summary, Chloramphenicol O-acetyltransferase is an enzyme that inactivates chloramphenicol by adding acetyl groups to it, making it an essential factor in bacterial resistance to this antibiotic.

A "reporter gene" is a type of gene that is linked to a gene of interest in order to make the expression or activity of that gene detectable. The reporter gene encodes for a protein that can be easily measured and serves as an indicator of the presence and activity of the gene of interest. Commonly used reporter genes include those that encode for fluorescent proteins, enzymes that catalyze colorimetric reactions, or proteins that bind to specific molecules.

In the context of genetics and genomics research, a reporter gene is often used in studies involving gene expression, regulation, and function. By introducing the reporter gene into an organism or cell, researchers can monitor the activity of the gene of interest in real-time or after various experimental treatments. The information obtained from these studies can help elucidate the role of specific genes in biological processes and diseases, providing valuable insights for basic research and therapeutic development.

Cytoplasmic receptors and nuclear receptors are two types of intracellular receptors that play crucial roles in signal transduction pathways and regulation of gene expression. They are classified based on their location within the cell. Here are the medical definitions for each:

1. Cytoplasmic Receptors: These are a group of intracellular receptors primarily found in the cytoplasm of cells, which bind to specific hormones, growth factors, or other signaling molecules. Upon binding, these receptors undergo conformational changes that allow them to interact with various partners, such as adapter proteins and enzymes, leading to activation of downstream signaling cascades. These pathways ultimately result in modulation of cellular processes like proliferation, differentiation, and apoptosis. Examples of cytoplasmic receptors include receptor tyrosine kinases (RTKs), serine/threonine kinase receptors, and cytokine receptors.
2. Nuclear Receptors: These are a distinct class of intracellular receptors that reside primarily in the nucleus of cells. They bind to specific ligands, such as steroid hormones, thyroid hormones, vitamin D, retinoic acid, and various other lipophilic molecules. Upon binding, nuclear receptors undergo conformational changes that facilitate their interaction with co-regulatory proteins and the DNA. This interaction results in the modulation of gene transcription, ultimately leading to alterations in protein expression and cellular responses. Examples of nuclear receptors include estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR), thyroid hormone receptor (TR), vitamin D receptor (VDR), and peroxisome proliferator-activated receptors (PPARs).

Both cytoplasmic and nuclear receptors are essential components of cellular communication networks, allowing cells to respond appropriately to extracellular signals and maintain homeostasis. Dysregulation of these receptors has been implicated in various diseases, including cancer, diabetes, and autoimmune disorders.

Bony callus is a medical term that refers to the specialized tissue that forms in response to a bone fracture. It is a crucial part of the natural healing process, as it helps to stabilize and protect the broken bone while it mends.

When a bone is fractured, the body responds by initiating an inflammatory response, which triggers the production of various cells and signaling molecules that promote healing. As part of this process, specialized cells called osteoblasts begin to produce new bone tissue at the site of the fracture. This tissue is initially soft and pliable, allowing it to bridge the gap between the broken ends of the bone.

Over time, this soft callus gradually hardens and calcifies, forming a bony callus that helps to stabilize the fracture and provide additional support as the bone heals. The bony callus is typically composed of a mixture of woven bone (which is less organized than normal bone) and more structured lamellar bone (which is similar in structure to normal bone).

As the bone continues to heal, the bony callus may be gradually remodeled and reshaped by osteoclasts, which are specialized cells that break down and remove excess or unwanted bone tissue. This process helps to restore the bone's original shape and strength, allowing it to function normally again.

It is worth noting that excessive bony callus formation can sometimes lead to complications, such as stiffness, pain, or decreased range of motion in the affected limb. In some cases, surgical intervention may be necessary to remove or reduce the size of the bony callus and promote proper healing.

Phagocytosis is the process by which certain cells in the body, known as phagocytes, engulf and destroy foreign particles, bacteria, or dead cells. This mechanism plays a crucial role in the immune system's response to infection and inflammation. Phagocytes, such as neutrophils, monocytes, and macrophages, have receptors on their surface that recognize and bind to specific molecules (known as antigens) on the target particles or microorganisms.

Once attached, the phagocyte extends pseudopodia (cell extensions) around the particle, forming a vesicle called a phagosome that completely encloses it. The phagosome then fuses with a lysosome, an intracellular organelle containing digestive enzymes and other chemicals. This fusion results in the formation of a phagolysosome, where the engulfed particle is broken down by the action of these enzymes, neutralizing its harmful effects and allowing for the removal of cellular debris or pathogens.

Phagocytosis not only serves as a crucial defense mechanism against infections but also contributes to tissue homeostasis by removing dead cells and debris.

The G1 phase, or Gap 1 phase, is the first phase of the cell cycle, during which the cell grows in size and synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis. During this phase, the cell also checks its growth and makes sure that it is large enough to proceed through the cell cycle. If the cell is not large enough, it will arrest in the G1 phase until it has grown sufficiently. The G1 phase is followed by the S phase, during which DNA replication occurs.

Antimicrobial cationic peptides (ACPs) are a group of small, naturally occurring peptides that possess broad-spectrum antimicrobial activity against various microorganisms, including bacteria, fungi, viruses, and parasites. They are called "cationic" because they contain positively charged amino acid residues (such as lysine and arginine), which allow them to interact with and disrupt the negatively charged membranes of microbial cells.

ACPs are produced by a wide range of organisms, including humans, animals, and plants, as part of their innate immune response to infection. They play an important role in protecting the host from invading pathogens by directly killing them or inhibiting their growth.

The antimicrobial activity of ACPs is thought to be mediated by their ability to disrupt the membranes of microbial cells, leading to leakage of cellular contents and death. Some ACPs may also have intracellular targets, such as DNA or protein synthesis, that contribute to their antimicrobial activity.

ACPs are being studied for their potential use as therapeutic agents to treat infectious diseases, particularly those caused by drug-resistant bacteria. However, their clinical application is still in the early stages of development due to concerns about their potential toxicity to host cells and the emergence of resistance mechanisms in microbial pathogens.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

Carboxylesterase is a type of enzyme that catalyzes the hydrolysis of ester bonds in carboxylic acid esters, producing alcohol and carboxylate products. These enzymes are widely distributed in various tissues, including the liver, intestines, and plasma. They play important roles in detoxification, metabolism, and the breakdown of xenobiotics (foreign substances) in the body.

Carboxylesterases can also catalyze the reverse reaction, forming esters from alcohols and carboxylates, which is known as transesterification or esterification. This activity has applications in industrial processes and biotechnology.

There are several families of carboxylesterases, with different substrate specificities, kinetic properties, and tissue distributions. These enzymes have been studied for their potential use in therapeutics, diagnostics, and drug delivery systems.

Cathelicidins are a family of antimicrobial peptides that are widely distributed in nature and play an important role in the innate immune system. They are expressed in various tissues, including the epithelia of the respiratory, gastrointestinal, and urogenital tracts, as well as in immune cells such as neutrophils and macrophages.

The human cathelicidin gene is called CAMP (camp gene) and encodes a precursor protein called hCAP-18 (human cationic antimicrobial protein of 18 kDa). After cleavage by proteolytic enzymes, the active peptide LL-37 is generated.

LL-37 has broad-spectrum antimicrobial activity against bacteria, viruses, fungi, and parasites. It also has immunomodulatory functions, such as chemotaxis of immune cells, modulation of cytokine production, and promotion of wound healing. Dysregulation of cathelicidins has been implicated in various inflammatory diseases, including chronic obstructive pulmonary disease (COPD), psoriasis, and rosacea.

Protein synthesis inhibitors are a class of medications or chemical substances that interfere with the process of protein synthesis in cells. Protein synthesis is the biological process by which cells create proteins, essential components for the structure, function, and regulation of tissues and organs. This process involves two main stages: transcription and translation.

Translation is the stage where the genetic information encoded in messenger RNA (mRNA) is translated into a specific sequence of amino acids, resulting in a protein molecule. Protein synthesis inhibitors work by targeting various components of the translation machinery, such as ribosomes, transfer RNAs (tRNAs), or translation factors, thereby preventing or disrupting the formation of new proteins.

These inhibitors have clinical applications in treating various conditions, including bacterial and viral infections, cancer, and autoimmune disorders. Some examples of protein synthesis inhibitors include:

1. Antibiotics: Certain antibiotics, like tetracyclines, macrolides, aminoglycosides, and chloramphenicol, target bacterial ribosomes and inhibit their ability to synthesize proteins, thereby killing or inhibiting the growth of bacteria.
2. Antiviral drugs: Protein synthesis inhibitors are used to treat viral infections by targeting various stages of the viral replication cycle, including protein synthesis. For example, ribavirin is an antiviral drug that can inhibit viral RNA-dependent RNA polymerase and mRNA capping, which are essential for viral protein synthesis.
3. Cancer therapeutics: Some chemotherapeutic agents target rapidly dividing cancer cells by interfering with their protein synthesis machinery. For instance, puromycin is an aminonucleoside antibiotic that can be incorporated into elongating polypeptide chains during translation, causing premature termination and inhibiting overall protein synthesis in cancer cells.
4. Immunosuppressive drugs: Protein synthesis inhibitors are also used as immunosuppressants to treat autoimmune disorders and prevent organ rejection after transplantation. For example, tacrolimus and cyclosporine bind to and inhibit the activity of calcineurin, a protein phosphatase that plays a crucial role in T-cell activation and cytokine production.

In summary, protein synthesis inhibitors are valuable tools for treating various diseases, including bacterial and viral infections, cancer, and autoimmune disorders. By targeting the protein synthesis machinery of pathogens or abnormal cells, these drugs can selectively inhibit their growth and proliferation while minimizing harm to normal cells.

Radioimmunoassay (RIA) is a highly sensitive analytical technique used in clinical and research laboratories to measure concentrations of various substances, such as hormones, vitamins, drugs, or tumor markers, in biological samples like blood, urine, or tissues. The method relies on the specific interaction between an antibody and its corresponding antigen, combined with the use of radioisotopes to quantify the amount of bound antigen.

In a typical RIA procedure, a known quantity of a radiolabeled antigen (also called tracer) is added to a sample containing an unknown concentration of the same unlabeled antigen. The mixture is then incubated with a specific antibody that binds to the antigen. During the incubation period, the antibody forms complexes with both the radiolabeled and unlabeled antigens.

After the incubation, the unbound (free) radiolabeled antigen is separated from the antibody-antigen complexes, usually through a precipitation or separation step involving centrifugation, filtration, or chromatography. The amount of radioactivity in the pellet (containing the antibody-antigen complexes) is then measured using a gamma counter or other suitable radiation detection device.

The concentration of the unlabeled antigen in the sample can be determined by comparing the ratio of bound to free radiolabeled antigen in the sample to a standard curve generated from known concentrations of unlabeled antigen and their corresponding bound/free ratios. The higher the concentration of unlabeled antigen in the sample, the lower the amount of radiolabeled antigen that will bind to the antibody, resulting in a lower bound/free ratio.

Radioimmunoassays offer high sensitivity, specificity, and accuracy, making them valuable tools for detecting and quantifying low levels of various substances in biological samples. However, due to concerns about radiation safety and waste disposal, alternative non-isotopic immunoassay techniques like enzyme-linked immunosorbent assays (ELISAs) have become more popular in recent years.

A chemical stimulation in a medical context refers to the process of activating or enhancing physiological or psychological responses in the body using chemical substances. These chemicals can interact with receptors on cells to trigger specific reactions, such as neurotransmitters and hormones that transmit signals within the nervous system and endocrine system.

Examples of chemical stimulation include the use of medications, drugs, or supplements that affect mood, alertness, pain perception, or other bodily functions. For instance, caffeine can chemically stimulate the central nervous system to increase alertness and decrease feelings of fatigue. Similarly, certain painkillers can chemically stimulate opioid receptors in the brain to reduce the perception of pain.

It's important to note that while chemical stimulation can have therapeutic benefits, it can also have adverse effects if used improperly or in excessive amounts. Therefore, it's essential to follow proper dosing instructions and consult with a healthcare provider before using any chemical substances for stimulation purposes.

Proto-oncogene proteins, such as c-Jun, are normal cellular proteins that play crucial roles in various cellular processes including cell growth, differentiation, and apoptosis (programmed cell death). When proto-oncogenes undergo mutations or are overexpressed, they can become oncogenes, promoting uncontrolled cell growth and leading to cancer.

The c-Jun protein is a component of the AP-1 transcription factor complex, which regulates gene expression by binding to specific DNA sequences. It is involved in various cellular responses such as proliferation, differentiation, and survival. Dysregulation of c-Jun has been implicated in several types of cancer, including lung, breast, and colon cancers.

Gas Chromatography-Mass Spectrometry (GC-MS) is a powerful analytical technique that combines the separating power of gas chromatography with the identification capabilities of mass spectrometry. This method is used to separate, identify, and quantify different components in complex mixtures.

In GC-MS, the mixture is first vaporized and carried through a long, narrow column by an inert gas (carrier gas). The various components in the mixture interact differently with the stationary phase inside the column, leading to their separation based on their partition coefficients between the mobile and stationary phases. As each component elutes from the column, it is then introduced into the mass spectrometer for analysis.

The mass spectrometer ionizes the sample, breaks it down into smaller fragments, and measures the mass-to-charge ratio of these fragments. This information is used to generate a mass spectrum, which serves as a unique "fingerprint" for each compound. By comparing the generated mass spectra with reference libraries or known standards, analysts can identify and quantify the components present in the original mixture.

GC-MS has wide applications in various fields such as forensics, environmental analysis, drug testing, and research laboratories due to its high sensitivity, specificity, and ability to analyze volatile and semi-volatile compounds.

Interleukin-1 (IL-1) is a type of cytokine, which are proteins that play a crucial role in cell signaling. Specifically, IL-1 is a pro-inflammatory cytokine that is involved in the regulation of immune and inflammatory responses in the body. It is produced by various cells, including monocytes, macrophages, and dendritic cells, in response to infection or injury.

IL-1 exists in two forms, IL-1α and IL-1β, which have similar biological activities but are encoded by different genes. Both forms of IL-1 bind to the same receptor, IL-1R, and activate intracellular signaling pathways that lead to the production of other cytokines, chemokines, and inflammatory mediators.

IL-1 has a wide range of biological effects, including fever induction, activation of immune cells, regulation of hematopoiesis (the formation of blood cells), and modulation of bone metabolism. Dysregulation of IL-1 production or activity has been implicated in various inflammatory diseases, such as rheumatoid arthritis, gout, and inflammatory bowel disease. Therefore, IL-1 is an important target for the development of therapies aimed at modulating the immune response and reducing inflammation.

Hyperphosphatemia is a medical condition characterized by an excessively high level of phosphate (a form of the chemical element phosphorus) in the blood. Phosphate is an important component of various biological molecules, such as DNA, RNA, and ATP, and it plays a crucial role in many cellular processes, including energy metabolism and signal transduction.

In healthy individuals, the concentration of phosphate in the blood is tightly regulated within a narrow range to maintain normal physiological functions. However, when the phosphate level rises above this range (typically defined as a serum phosphate level greater than 4.5 mg/dL or 1.46 mmol/L), it can lead to hyperphosphatemia.

Hyperphosphatemia can result from various underlying medical conditions, including:

* Kidney dysfunction: The kidneys are responsible for filtering excess phosphate out of the blood and excreting it in the urine. When the kidneys fail to function properly, they may be unable to remove enough phosphate, leading to its accumulation in the blood.
* Hypoparathyroidism: The parathyroid glands produce a hormone called parathyroid hormone (PTH), which helps regulate calcium and phosphate levels in the body. In hypoparathyroidism, the production of PTH is insufficient, leading to an increase in phosphate levels.
* Hyperparathyroidism: In contrast, excessive production of PTH can also lead to hyperphosphatemia by increasing the release of phosphate from bones and decreasing its reabsorption in the kidneys.
* Excessive intake of phosphate-rich foods or supplements: Consuming large amounts of phosphate-rich foods, such as dairy products, nuts, and legumes, or taking phosphate supplements can raise blood phosphate levels.
* Tumor lysis syndrome: This is a complication that can occur after the treatment of certain types of cancer, particularly hematological malignancies. The rapid destruction of cancer cells releases large amounts of intracellular contents, including phosphate, into the bloodstream, leading to hyperphosphatemia.
* Rhabdomyolysis: This is a condition in which muscle tissue breaks down, releasing its contents, including phosphate, into the bloodstream. It can be caused by various factors, such as trauma, infection, or drug toxicity.

Hyperphosphatemia can have several adverse effects on the body, including calcification of soft tissues, kidney damage, and metabolic disturbances. Therefore, it is essential to diagnose and manage hyperphosphatemia promptly to prevent complications. Treatment options may include dietary modifications, medications that bind phosphate in the gastrointestinal tract, and dialysis in severe cases.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Cytochrome P-450 CYP3A is a subfamily of the cytochrome P-450 enzyme superfamily, which are primarily involved in drug metabolism in the human body. These enzymes are found predominantly in the liver, but also in other tissues such as the small intestine, kidneys, and brain.

CYP3A enzymes are responsible for metabolizing a wide variety of drugs, including many statins, benzodiazepines, antidepressants, and opioids. They can also metabolize endogenous compounds such as steroids and bile acids. The activity of CYP3A enzymes can be influenced by various factors, including genetic polymorphisms, age, sex, pregnancy, and the presence of other drugs or diseases.

The name "cytochrome P-450" refers to the fact that these enzymes contain a heme group that absorbs light at a wavelength of 450 nanometers when it is complexed with carbon monoxide. The term "CYP3A" denotes the specific subfamily of cytochrome P-450 enzymes that share a high degree of sequence similarity and function.

Experimental leukemia refers to the stage of research or clinical trials where new therapies, treatments, or diagnostic methods are being studied for leukemia. Leukemia is a type of cancer that affects the blood and bone marrow, leading to an overproduction of abnormal white blood cells.

In the experimental stage, researchers investigate various aspects of leukemia, such as its causes, progression, and potential treatments. They may conduct laboratory studies using cell cultures or animal models to understand the disease better and test new therapeutic approaches. Additionally, clinical trials may be conducted to evaluate the safety and efficacy of novel treatments in human patients with leukemia.

Experimental research in leukemia is crucial for advancing our understanding of the disease and developing more effective treatment strategies. It involves a rigorous and systematic process that adheres to ethical guidelines and scientific standards to ensure the validity and reliability of the findings.

Distal kidney tubules are the final segment of the renal tubule in the nephron of the kidney. The nephron is the basic unit of the kidney that filters blood and produces urine. After the filtrate leaves the glomerulus, it enters the proximal tubule where most of the reabsorption of water, electrolytes, and nutrients occurs.

The filtrate then moves into the loop of Henle, which is divided into a thin and thick descending limb and a thin and thick ascending limb. The loop of Henle helps to establish a concentration gradient in the medullary interstitium, allowing for the reabsorption of water in the collecting ducts.

The distal tubule is the last segment of the renal tubule before the filtrate enters the collecting duct. It is a relatively short structure that receives filtrate from the thick ascending limb of the loop of Henle. The distal tubule plays an important role in regulating electrolyte and water balance by actively transporting ions such as sodium, potassium, and chloride.

The distal tubule also contains specialized cells called principal cells and intercalated cells that are responsible for secreting or reabsorbing hydrogen and potassium ions to maintain acid-base balance. Additionally, the distal tubule is a site of action for several hormones, including aldosterone, which stimulates sodium reabsorption and potassium excretion, and vasopressin (antidiuretic hormone), which promotes water reabsorption in the collecting ducts.

"Swine" is a common term used to refer to even-toed ungulates of the family Suidae, including domestic pigs and wild boars. However, in a medical context, "swine" often appears in the phrase "swine flu," which is a strain of influenza virus that typically infects pigs but can also cause illness in humans. The 2009 H1N1 pandemic was caused by a new strain of swine-origin influenza A virus, which was commonly referred to as "swine flu." It's important to note that this virus is not transmitted through eating cooked pork products; it spreads from person to person, mainly through respiratory droplets produced when an infected person coughs or sneezes.

Parathyroidectomy is a surgical procedure for the removal of one or more of the parathyroid glands. These glands are located in the neck and are responsible for producing parathyroid hormone (PTH), which helps regulate the levels of calcium and phosphorus in the body.

Parathyroidectomy is typically performed to treat conditions such as hyperparathyroidism, where one or more of the parathyroid glands become overactive and produce too much PTH. This can lead to high levels of calcium in the blood, which can cause symptoms such as weakness, fatigue, bone pain, kidney stones, and mental confusion.

There are different types of parathyroidectomy procedures, including:

* Partial parathyroidectomy: removal of one or more, but not all, of the parathyroid glands.
* Total parathyroidectomy: removal of all four parathyroid glands.
* Subtotal parathyroidectomy: removal of three and a half of the four parathyroid glands, leaving a small portion of one gland to prevent hypoparathyroidism (a condition where the body produces too little PTH).

The choice of procedure depends on the underlying condition and its severity. After the surgery, patients may need to have their calcium levels monitored and may require calcium and vitamin D supplements to maintain normal calcium levels in the blood.

Anticarcinogenic agents are substances that prevent, inhibit or reduce the development of cancer. They can be natural or synthetic compounds that interfere with the process of carcinogenesis at various stages, such as initiation, promotion, and progression. Anticarcinogenic agents may work by preventing DNA damage, promoting DNA repair, reducing inflammation, inhibiting cell proliferation, inducing apoptosis (programmed cell death), or modulating immune responses.

Examples of anticarcinogenic agents include chemopreventive agents, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and retinoids; phytochemicals found in fruits, vegetables, and other plant-based foods; and medications used to treat cancer, such as chemotherapy, radiation therapy, and targeted therapies.

It is important to note that while some anticarcinogenic agents have been shown to be effective in preventing or reducing the risk of certain types of cancer, they may also have potential side effects and risks. Therefore, it is essential to consult with a healthcare professional before using any anticarcinogenic agent for cancer prevention or treatment purposes.

Enzyme activation refers to the process by which an enzyme becomes biologically active and capable of carrying out its specific chemical or biological reaction. This is often achieved through various post-translational modifications, such as proteolytic cleavage, phosphorylation, or addition of cofactors or prosthetic groups to the enzyme molecule. These modifications can change the conformation or structure of the enzyme, exposing or creating a binding site for the substrate and allowing the enzymatic reaction to occur.

For example, in the case of proteolytic cleavage, an inactive precursor enzyme, known as a zymogen, is cleaved into its active form by a specific protease. This is seen in enzymes such as trypsin and chymotrypsin, which are initially produced in the pancreas as inactive precursors called trypsinogen and chymotrypsinogen, respectively. Once they reach the small intestine, they are activated by enteropeptidase, a protease that cleaves a specific peptide bond, releasing the active enzyme.

Phosphorylation is another common mechanism of enzyme activation, where a phosphate group is added to a specific serine, threonine, or tyrosine residue on the enzyme by a protein kinase. This modification can alter the conformation of the enzyme and create a binding site for the substrate, allowing the enzymatic reaction to occur.

Enzyme activation is a crucial process in many biological pathways, as it allows for precise control over when and where specific reactions take place. It also provides a mechanism for regulating enzyme activity in response to various signals and stimuli, such as hormones, neurotransmitters, or changes in the intracellular environment.

A dietary supplement is a product that contains nutrients, such as vitamins, minerals, amino acids, herbs or other botanicals, and is intended to be taken by mouth, to supplement the diet. Dietary supplements can include a wide range of products, such as vitamin and mineral supplements, herbal supplements, and sports nutrition products.

Dietary supplements are not intended to treat, diagnose, cure, or alleviate the effects of diseases. They are intended to be used as a way to add extra nutrients to the diet or to support specific health functions. It is important to note that dietary supplements are not subject to the same rigorous testing and regulations as drugs, so it is important to choose products carefully and consult with a healthcare provider if you have any questions or concerns about using them.

Cell surface receptors, also known as membrane receptors, are proteins located on the cell membrane that bind to specific molecules outside the cell, known as ligands. These receptors play a crucial role in signal transduction, which is the process of converting an extracellular signal into an intracellular response.

Cell surface receptors can be classified into several categories based on their structure and mechanism of action, including:

1. Ion channel receptors: These receptors contain a pore that opens to allow ions to flow across the cell membrane when they bind to their ligands. This ion flux can directly activate or inhibit various cellular processes.
2. G protein-coupled receptors (GPCRs): These receptors consist of seven transmembrane domains and are associated with heterotrimeric G proteins that modulate intracellular signaling pathways upon ligand binding.
3. Enzyme-linked receptors: These receptors possess an intrinsic enzymatic activity or are linked to an enzyme, which becomes activated when the receptor binds to its ligand. This activation can lead to the initiation of various signaling cascades within the cell.
4. Receptor tyrosine kinases (RTKs): These receptors contain intracellular tyrosine kinase domains that become activated upon ligand binding, leading to the phosphorylation and activation of downstream signaling molecules.
5. Integrins: These receptors are transmembrane proteins that mediate cell-cell or cell-matrix interactions by binding to extracellular matrix proteins or counter-receptors on adjacent cells. They play essential roles in cell adhesion, migration, and survival.

Cell surface receptors are involved in various physiological processes, including neurotransmission, hormone signaling, immune response, and cell growth and differentiation. Dysregulation of these receptors can contribute to the development of numerous diseases, such as cancer, diabetes, and neurological disorders.

Biological transport refers to the movement of molecules, ions, or solutes across biological membranes or through cells in living organisms. This process is essential for maintaining homeostasis, regulating cellular functions, and enabling communication between cells. There are two main types of biological transport: passive transport and active transport.

Passive transport does not require the input of energy and includes:

1. Diffusion: The random movement of molecules from an area of high concentration to an area of low concentration until equilibrium is reached.
2. Osmosis: The diffusion of solvent molecules (usually water) across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
3. Facilitated diffusion: The assisted passage of polar or charged substances through protein channels or carriers in the cell membrane, which increases the rate of diffusion without consuming energy.

Active transport requires the input of energy (in the form of ATP) and includes:

1. Primary active transport: The direct use of ATP to move molecules against their concentration gradient, often driven by specific transport proteins called pumps.
2. Secondary active transport: The coupling of the movement of one substance down its electrochemical gradient with the uphill transport of another substance, mediated by a shared transport protein. This process is also known as co-transport or counter-transport.

Cyclin-dependent kinase inhibitor p21, also known as CDKN1A or p21/WAF1/CIP1, is a protein that regulates the cell cycle. It inhibits the activity of cyclin-dependent kinases (CDKs), which are enzymes that play crucial roles in controlling the progression of the cell cycle.

The binding of p21 to CDKs prevents the phosphorylation and activation of downstream targets, leading to cell cycle arrest. This protein is transcriptionally activated by tumor suppressor protein p53 in response to DNA damage or other stress signals, and it functions as an important mediator of p53-dependent growth arrest.

By inhibiting CDKs, p21 helps to ensure that cells do not proceed through the cell cycle until damaged DNA has been repaired, thereby preventing the propagation of potentially harmful mutations. Additionally, p21 has been implicated in other cellular processes such as apoptosis, differentiation, and senescence. Dysregulation of p21 has been associated with various human diseases, including cancer.

Immunoblotting, also known as western blotting, is a laboratory technique used in molecular biology and immunogenetics to detect and quantify specific proteins in a complex mixture. This technique combines the electrophoretic separation of proteins by gel electrophoresis with their detection using antibodies that recognize specific epitopes (protein fragments) on the target protein.

The process involves several steps: first, the protein sample is separated based on size through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Next, the separated proteins are transferred onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric field. The membrane is then blocked with a blocking agent to prevent non-specific binding of antibodies.

After blocking, the membrane is incubated with a primary antibody that specifically recognizes the target protein. Following this, the membrane is washed to remove unbound primary antibodies and then incubated with a secondary antibody conjugated to an enzyme such as horseradish peroxidase (HRP) or alkaline phosphatase (AP). The enzyme catalyzes a colorimetric or chemiluminescent reaction that allows for the detection of the target protein.

Immunoblotting is widely used in research and clinical settings to study protein expression, post-translational modifications, protein-protein interactions, and disease biomarkers. It provides high specificity and sensitivity, making it a valuable tool for identifying and quantifying proteins in various biological samples.

Bile is a digestive fluid that is produced by the liver and stored in the gallbladder. It plays an essential role in the digestion and absorption of fats and fat-soluble vitamins in the small intestine. Bile consists of bile salts, bilirubin, cholesterol, phospholipids, electrolytes, and water.

Bile salts are amphipathic molecules that help to emulsify fats into smaller droplets, increasing their surface area and allowing for more efficient digestion by enzymes such as lipase. Bilirubin is a breakdown product of hemoglobin from red blood cells and gives bile its characteristic greenish-brown color.

Bile is released into the small intestine in response to food, particularly fats, entering the digestive tract. It helps to break down large fat molecules into smaller ones that can be absorbed through the walls of the intestines and transported to other parts of the body for energy or storage.

MAP Kinase Kinase Kinase 1 (MAP3K1) is a serine/threonine protein kinase that belongs to the MAPKKK family. It plays a crucial role in intracellular signaling pathways, particularly the mitogen-activated protein kinase (MAPK) cascades. These cascades are involved in various cellular processes such as proliferation, differentiation, and apoptosis.

MAP3K1 activates MAPKKs (MAP Kinase Kinases) by phosphorylating them on specific serine and threonine residues. In turn, activated MAPKKs phosphorylate and activate MAPKs, which then regulate the activity of various transcription factors and other downstream targets.

Mutations in MAP3K1 have been implicated in several human diseases, including cancer and developmental disorders. For example, gain-of-function mutations in MAP3K1 can lead to aberrant activation of MAPK signaling pathways, promoting tumor growth and progression. On the other hand, loss-of-function mutations in MAP3K1 have been associated with developmental defects such as craniofacial anomalies and skeletal malformations.

Amanitins are a type of bicyclic octapeptide toxin found in several species of mushrooms belonging to the Amanita genus, including the death cap (Amanita phalloides) and the destroying angel (Amanita virosa). These toxins are part of the group of compounds known as amatoxins.

Amanitins are highly toxic to humans and other animals, affecting the liver and kidneys in particular. They work by inhibiting RNA polymerase II, an enzyme that plays a crucial role in gene expression by transcribing DNA into messenger RNA (mRNA). This interference with protein synthesis can lead to severe damage to cells and tissues, potentially resulting in organ failure and death if left untreated.

Symptoms of amanitin poisoning typically appear in two phases. The first phase, which occurs within 6-24 hours after ingestion, includes gastrointestinal distress such as vomiting, diarrhea, and abdominal pain. This initial phase may subside for a short period, giving a false sense of recovery. However, the second phase, which can occur 3-7 days later, is characterized by liver and kidney damage, with symptoms such as jaundice, disorientation, seizures, coma, and ultimately, multiple organ failure if not treated promptly and effectively.

Treatment for amanitin poisoning usually involves supportive care, such as fluid replacement and addressing any complications that arise. In some cases, medications like silibinin (from milk thistle) or activated charcoal may be used to help reduce the absorption and toxicity of the amanitins. Additionally, liver transplantation might be considered in severe cases where organ failure is imminent. Prevention is key when it comes to amanitin poisoning, as there is no antidote available. Being able to identify and avoid potentially deadly mushrooms is essential for foragers and those who enjoy gathering wild fungi.

Uremia is not a disease itself, but rather it's a condition that results from the buildup of waste products in the blood due to kidney failure. The term "uremia" comes from the word "urea," which is one of the waste products that accumulate when the kidneys are not functioning properly.

In uremia, the kidneys are unable to effectively filter waste and excess fluids from the blood, leading to a variety of symptoms such as nausea, vomiting, fatigue, itching, mental confusion, and ultimately, if left untreated, can lead to coma and death. It is a serious condition that requires immediate medical attention, often involving dialysis or a kidney transplant to manage the underlying kidney dysfunction.

Fibroblasts are specialized cells that play a critical role in the body's immune response and wound healing process. They are responsible for producing and maintaining the extracellular matrix (ECM), which is the non-cellular component present within all tissues and organs, providing structural support and biochemical signals for surrounding cells.

Fibroblasts produce various ECM proteins such as collagens, elastin, fibronectin, and laminins, forming a complex network of fibers that give tissues their strength and flexibility. They also help in the regulation of tissue homeostasis by controlling the turnover of ECM components through the process of remodeling.

In response to injury or infection, fibroblasts become activated and start to proliferate rapidly, migrating towards the site of damage. Here, they participate in the inflammatory response, releasing cytokines and chemokines that attract immune cells to the area. Additionally, they deposit new ECM components to help repair the damaged tissue and restore its functionality.

Dysregulation of fibroblast activity has been implicated in several pathological conditions, including fibrosis (excessive scarring), cancer (where they can contribute to tumor growth and progression), and autoimmune diseases (such as rheumatoid arthritis).

NCOR1 (Nuclear Receptor Co-Repressor 1) is a corepressor protein that interacts with nuclear receptors and other transcription factors to regulate gene expression. It functions as a part of large multiprotein complexes, which also include histone deacetylases (HDACs), to mediate the repression of gene transcription. NCOR1 is involved in various cellular processes, including development, differentiation, and metabolism. Mutations in the NCOR1 gene have been associated with certain genetic disorders, such as Rubinstein-Taybi syndrome.

Cyclin-Dependent Kinase Inhibitor p27, also known as CDKN1B or p27Kip1, is a protein that regulates the cell cycle. It inhibits the activity of certain cyclin-dependent kinases (CDKs), which are enzymes that play key roles in regulating the progression of the cell cycle.

The cell cycle is a series of events that cells undergo as they grow and divide. Cyclins and CDKs help to control the different stages of the cell cycle by activating and deactivating various proteins at specific times. The p27 protein acts as a brake on the cell cycle, preventing cells from dividing too quickly or abnormally.

When p27 binds to a CDK-cyclin complex, it prevents the complex from phosphorylating its target proteins, which are necessary for the progression of the cell cycle. By inhibiting CDK activity, p27 helps to ensure that cells divide only when the proper conditions are met.

Mutations in the CDKN1B gene, which encodes p27, have been associated with several types of cancer, including breast, lung, and prostate cancer. These mutations can lead to decreased levels of p27 or impaired function, allowing cells to divide uncontrollably and form tumors.

Tumor Necrosis Factor-alpha (TNF-α) is a cytokine, a type of small signaling protein involved in immune response and inflammation. It is primarily produced by activated macrophages, although other cell types such as T-cells, natural killer cells, and mast cells can also produce it.

TNF-α plays a crucial role in the body's defense against infection and tissue injury by mediating inflammatory responses, activating immune cells, and inducing apoptosis (programmed cell death) in certain types of cells. It does this by binding to its receptors, TNFR1 and TNFR2, which are found on the surface of many cell types.

In addition to its role in the immune response, TNF-α has been implicated in the pathogenesis of several diseases, including autoimmune disorders such as rheumatoid arthritis, inflammatory bowel disease, and psoriasis, as well as cancer, where it can promote tumor growth and metastasis.

Therapeutic agents that target TNF-α, such as infliximab, adalimumab, and etanercept, have been developed to treat these conditions. However, these drugs can also increase the risk of infections and other side effects, so their use must be carefully monitored.

Bone remodeling is the normal and continuous process by which bone tissue is removed from the skeleton (a process called resorption) and new bone tissue is formed (a process called formation). This ongoing cycle allows bones to repair microdamage, adjust their size and shape in response to mechanical stress, and maintain mineral homeostasis. The cells responsible for bone resorption are osteoclasts, while the cells responsible for bone formation are osteoblasts. These two cell types work together to maintain the structural integrity and health of bones throughout an individual's life.

During bone remodeling, the process can be divided into several stages:

1. Activation: The initiation of bone remodeling is triggered by various factors such as microdamage, hormonal changes, or mechanical stress. This leads to the recruitment and activation of osteoclast precursor cells.
2. Resorption: Osteoclasts attach to the bone surface and create a sealed compartment called a resorption lacuna. They then secrete acid and enzymes that dissolve and digest the mineralized matrix, creating pits or cavities on the bone surface. This process helps remove old or damaged bone tissue and releases calcium and phosphate ions into the bloodstream.
3. Reversal: After resorption is complete, the osteoclasts undergo apoptosis (programmed cell death), and mononuclear cells called reversal cells appear on the resorbed surface. These cells prepare the bone surface for the next stage by cleaning up debris and releasing signals that attract osteoblast precursors.
4. Formation: Osteoblasts, derived from mesenchymal stem cells, migrate to the resorbed surface and begin producing a new organic matrix called osteoid. As the osteoid mineralizes, it forms a hard, calcified structure that gradually replaces the resorbed bone tissue. The osteoblasts may become embedded within this newly formed bone as they differentiate into osteocytes, which are mature bone cells responsible for maintaining bone homeostasis and responding to mechanical stress.
5. Mineralization: Over time, the newly formed bone continues to mineralize, becoming stronger and more dense. This process helps maintain the structural integrity of the skeleton and ensures adequate calcium storage.

Throughout this continuous cycle of bone remodeling, hormones, growth factors, and mechanical stress play crucial roles in regulating the balance between resorption and formation. Disruptions to this delicate equilibrium can lead to various bone diseases, such as osteoporosis, where excessive resorption results in weakened bones and increased fracture risk.

Annexin A2 is a protein found in various types of cells, including those that line the inside of blood vessels. It is a member of the annexin family of proteins, which are characterized by their ability to bind to calcium ions and membranes. Annexin A2 is involved in several cellular processes, including the regulation of ion channels, the modulation of enzyme activity, and the promotion of cell adhesion and migration. It also plays a role in the coagulation of blood, and has been implicated in the development and progression of various diseases, including cancer and cardiovascular disease.

Dermatologic agents are medications, chemicals, or other substances that are applied to the skin (dermis) for therapeutic or cosmetic purposes. They can be used to treat various skin conditions such as acne, eczema, psoriasis, fungal infections, and wounds. Dermatologic agents include topical corticosteroids, antibiotics, antifungals, retinoids, benzoyl peroxide, salicylic acid, and many others. They can come in various forms such as creams, ointments, gels, lotions, solutions, and patches. It is important to follow the instructions for use carefully to ensure safety and effectiveness.

Nitroblue Tetrazolium (NBT) is not a medical term per se, but a chemical compound that is widely used in scientific research and diagnostic tests. It's primarily used as an electron acceptor in various biochemical assays to detect the presence of certain enzymes or reactive oxygen species (ROS).

In a medical context, NBT is often used in the NBT reduction test, which is a diagnostic procedure to identify patients with chronic granulomatous disease (CGD), an inherited immunodeficiency disorder. In this test, white blood cells called phagocytes from the patient's blood sample are incubated with NBT and a stimulus that triggers their respiratory burst, such as bacterial particles. If the phagocytes can produce superoxide radicals during the respiratory burst, these radicals reduce NBT to form a blue-black insoluble formazan precipitate. In CGD patients, who have impaired production of ROS, there is no or significantly reduced formazan formation, indicating an abnormal NBT reduction test result.

Ketoconazole is an antifungal medication that is primarily used to treat various fungal infections, including those caused by dermatophytes, Candida, and pityrosporum. It works by inhibiting the synthesis of ergosterol, a crucial component of fungal cell membranes, which leads to increased permeability and ultimately results in fungal cell death.

Ketoconazole is available as an oral tablet for systemic use and as a topical cream or shampoo for localized applications. The oral formulation is used to treat severe or invasive fungal infections, while the topical preparations are primarily indicated for skin and scalp infections, such as athlete's foot, ringworm, jock itch, candidiasis, and seborrheic dermatitis.

Common side effects of oral ketoconazole include nausea, vomiting, headache, and altered liver function tests. Rare but serious adverse reactions may include hepatotoxicity, adrenal insufficiency, and interactions with other medications that can affect the metabolism and elimination of drugs. Topical ketoconazole is generally well-tolerated, with local irritation being the most common side effect.

It's important to note that due to its potential for serious liver toxicity and drug-drug interactions, oral ketoconazole has been largely replaced by other antifungal agents, such as fluconazole and itraconazole, which have more favorable safety profiles. Topical ketoconazole remains a valuable option for treating localized fungal infections due to its effectiveness and lower risk of systemic side effects.

Enterohepatic circulation is the process by which certain substances, such as bile salts, bilirubin, and some drugs, are chemically modified and reabsorbed in the enterohepatic system. This system includes the liver, bile ducts, and small intestine.

In the case of bile salts, they are synthesized in the liver, secreted into the bile, and stored in the gallbladder. After a meal, the gallbladder contracts and releases bile into the small intestine to aid in fat digestion. The bile salts help to emulsify fats, allowing them to be absorbed by the intestines. Once absorbed, they are transported back to the liver through the portal vein, where they can be reused for further bile production.

Similarly, bilirubin, a waste product produced from the breakdown of red blood cells, is also conjugated in the liver and excreted into the bile. In the small intestine, bacteria break down bilirubin into colorless urobilinogen, which can be reabsorbed and transported back to the liver for further processing.

Certain drugs may also undergo enterohepatic circulation, where they are metabolized in the liver, excreted into the bile, and then reabsorbed in the small intestine. This can prolong the duration of drug action and affect its overall effectiveness.

Osteoporosis is a systemic skeletal disease characterized by low bone mass, deterioration of bone tissue, and disruption of bone architecture, leading to increased risk of fractures, particularly in the spine, wrist, and hip. It mainly affects older people, especially postmenopausal women, due to hormonal changes that reduce bone density. Osteoporosis can also be caused by certain medications, medical conditions, or lifestyle factors such as smoking, alcohol abuse, and a lack of calcium and vitamin D in the diet. The diagnosis is often made using bone mineral density testing, and treatment may include medication to slow bone loss, promote bone formation, and prevent fractures.

Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.

A phenotype is the physical or biochemical expression of an organism's genes, or the observable traits and characteristics resulting from the interaction of its genetic constitution (genotype) with environmental factors. These characteristics can include appearance, development, behavior, and resistance to disease, among others. Phenotypes can vary widely, even among individuals with identical genotypes, due to differences in environmental influences, gene expression, and genetic interactions.

Cyclins are a family of regulatory proteins that play a crucial role in the cell cycle, which is the series of events that take place as a cell grows, divides, and produces two daughter cells. They are called cyclins because their levels fluctuate or cycle during the different stages of the cell cycle.

Cyclins function as subunits of serine/threonine protein kinase complexes, forming an active enzyme that adds phosphate groups to other proteins, thereby modifying their activity. This post-translational modification is a critical mechanism for controlling various cellular processes, including the regulation of the cell cycle.

There are several types of cyclins (A, B, D, and E), each of which is active during specific phases of the cell cycle:

1. Cyclin D: Expressed in the G1 phase, it helps to initiate the cell cycle by activating cyclin-dependent kinases (CDKs) that promote progression through the G1 restriction point.
2. Cyclin E: Active during late G1 and early S phases, it forms a complex with CDK2 to regulate the transition from G1 to S phase, where DNA replication occurs.
3. Cyclin A: Expressed in the S and G2 phases, it associates with both CDK2 and CDK1 to control the progression through the S and G2 phases and entry into mitosis (M phase).
4. Cyclin B: Active during late G2 and M phases, it partners with CDK1 to regulate the onset of mitosis by controlling the breakdown of the nuclear envelope, chromosome condensation, and spindle formation.

The activity of cyclins is tightly controlled through several mechanisms, including transcriptional regulation, protein degradation, and phosphorylation/dephosphorylation events. Dysregulation of cyclin expression or function can lead to uncontrolled cell growth and proliferation, which are hallmarks of cancer.

Biological transport, active is the process by which cells use energy to move materials across their membranes from an area of lower concentration to an area of higher concentration. This type of transport is facilitated by specialized proteins called transporters or pumps that are located in the cell membrane. These proteins undergo conformational changes to physically carry the molecules through the lipid bilayer of the membrane, often against their concentration gradient.

Active transport requires energy because it works against the natural tendency of molecules to move from an area of higher concentration to an area of lower concentration, a process known as diffusion. Cells obtain this energy in the form of ATP (adenosine triphosphate), which is produced through cellular respiration.

Examples of active transport include the uptake of glucose and amino acids into cells, as well as the secretion of hormones and neurotransmitters. The sodium-potassium pump, which helps maintain resting membrane potential in nerve and muscle cells, is a classic example of an active transporter.

Androgens are a class of hormones that are primarily responsible for the development and maintenance of male sexual characteristics and reproductive function. Testosterone is the most well-known androgen, but other androgens include dehydroepiandrosterone (DHEA), androstenedione, and dihydrotestosterone (DHT).

Androgens are produced primarily by the testes in men and the ovaries in women, although small amounts are also produced by the adrenal glands in both sexes. They play a critical role in the development of male secondary sexual characteristics during puberty, such as the growth of facial hair, deepening of the voice, and increased muscle mass.

In addition to their role in sexual development and function, androgens also have important effects on bone density, mood, and cognitive function. Abnormal levels of androgens can contribute to a variety of medical conditions, including infertility, erectile dysfunction, acne, hirsutism (excessive hair growth), and prostate cancer.

Retinoid X Receptor alpha (RXR-alpha) is a type of nuclear receptor protein that plays a crucial role in the regulation of gene transcription. It binds to specific sequences of DNA, known as response elements, and regulates the expression of target genes involved in various biological processes such as cell differentiation, development, and homeostasis.

RXR-alpha can form heterodimers with other nuclear receptors, including retinoic acid receptors (RARs), vitamin D receptor (VDR), thyroid hormone receptor (THR), and peroxisome proliferator-activated receptors (PPARs). The formation of these heterodimers allows RXR-alpha to modulate the transcriptional activity of its partner nuclear receptors, thereby regulating a wide range of physiological functions.

Retinoid X Receptor alpha is widely expressed in various tissues and organs, including the liver, kidney, heart, brain, and retina. Mutations in the RXR-alpha gene have been associated with several human diseases, such as metabolic disorders, developmental abnormalities, and cancer. Therefore, RXR-alpha is an important therapeutic target for the treatment of various diseases.

RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.

Microvilli are small, finger-like projections that line the apical surface (the side facing the lumen) of many types of cells, including epithelial and absorptive cells. They serve to increase the surface area of the cell membrane, which in turn enhances the cell's ability to absorb nutrients, transport ions, and secrete molecules.

Microvilli are typically found in high density and are arranged in a brush-like border called the "brush border." They contain a core of actin filaments that provide structural support and allow for their movement and flexibility. The membrane surrounding microvilli contains various transporters, channels, and enzymes that facilitate specific functions related to absorption and secretion.

In summary, microvilli are specialized structures on the surface of cells that enhance their ability to interact with their environment by increasing the surface area for transport and secretory processes.

Pregnancy is a physiological state or condition where a fertilized egg (zygote) successfully implants and grows in the uterus of a woman, leading to the development of an embryo and finally a fetus. This process typically spans approximately 40 weeks, divided into three trimesters, and culminates in childbirth. Throughout this period, numerous hormonal and physical changes occur to support the growing offspring, including uterine enlargement, breast development, and various maternal adaptations to ensure the fetus's optimal growth and well-being.

Oral administration is a route of giving medications or other substances by mouth. This can be in the form of tablets, capsules, liquids, pastes, or other forms that can be swallowed. Once ingested, the substance is absorbed through the gastrointestinal tract and enters the bloodstream to reach its intended target site in the body. Oral administration is a common and convenient route of medication delivery, but it may not be appropriate for all substances or in certain situations, such as when rapid onset of action is required or when the patient has difficulty swallowing.

Chronic Renal Insufficiency (CRI) is a medical condition characterized by a gradual and progressive loss of kidney function over a period of months or years. It is also known as Chronic Kidney Disease (CKD). The main function of the kidneys is to filter waste products and excess fluids from the blood, which are then excreted in the urine. When the kidneys become insufficient, these waste products and fluids accumulate in the body, leading to various complications.

CRI is defined as a glomerular filtration rate (GFR) of less than 60 ml/min/1.73m2 for three months or more, regardless of cause. GFR is a measure of kidney function that estimates how well the kidneys are filtering waste products from the blood. The condition is classified into five stages based on the severity of the disease and the GFR value.

Stage 1: GFR greater than or equal to 90 ml/min/1.73m2
Stage 2: GFR between 60-89 ml/min/1.73m2
Stage 3: GFR between 30-59 ml/min/1.73m2
Stage 4: GFR between 15-29 ml/min/1.73m2
Stage 5: GFR less than 15 ml/min/1.73m2 or dialysis

CRI can be caused by various underlying conditions such as diabetes, hypertension, glomerulonephritis, polycystic kidney disease, and other genetic or acquired disorders. Symptoms of CRI may include fatigue, weakness, loss of appetite, swelling in the legs and ankles, shortness of breath, and changes in urination patterns. Treatment for CRI focuses on slowing down the progression of the disease, managing symptoms, and preventing complications. This may involve lifestyle modifications, medication, dialysis, or kidney transplantation.

Cytokines are a broad and diverse category of small signaling proteins that are secreted by various cells, including immune cells, in response to different stimuli. They play crucial roles in regulating the immune response, inflammation, hematopoiesis, and cellular communication.

Cytokines mediate their effects by binding to specific receptors on the surface of target cells, which triggers intracellular signaling pathways that ultimately result in changes in gene expression, cell behavior, and function. Some key functions of cytokines include:

1. Regulating the activation, differentiation, and proliferation of immune cells such as T cells, B cells, natural killer (NK) cells, and macrophages.
2. Coordinating the inflammatory response by recruiting immune cells to sites of infection or tissue damage and modulating their effector functions.
3. Regulating hematopoiesis, the process of blood cell formation in the bone marrow, by controlling the proliferation, differentiation, and survival of hematopoietic stem and progenitor cells.
4. Modulating the development and function of the nervous system, including neuroinflammation, neuroprotection, and neuroregeneration.

Cytokines can be classified into several categories based on their structure, function, or cellular origin. Some common types of cytokines include interleukins (ILs), interferons (IFNs), tumor necrosis factors (TNFs), chemokines, colony-stimulating factors (CSFs), and transforming growth factors (TGFs). Dysregulation of cytokine production and signaling has been implicated in various pathological conditions, such as autoimmune diseases, chronic inflammation, cancer, and neurodegenerative disorders.

Thyroidectomy is a surgical procedure where all or part of the thyroid gland is removed. The thyroid gland is a butterfly-shaped endocrine gland located in the neck, responsible for producing hormones that regulate metabolism, growth, and development.

There are different types of thyroidectomy procedures, including:

1. Total thyroidectomy: Removal of the entire thyroid gland.
2. Partial (or subtotal) thyroidectomy: Removal of a portion of the thyroid gland.
3. Hemithyroidectomy: Removal of one lobe of the thyroid gland, often performed to treat benign solitary nodules or differentiated thyroid cancer.

Thyroidectomy may be recommended for various reasons, such as treating thyroid nodules, goiter, hyperthyroidism (overactive thyroid), or thyroid cancer. Potential risks and complications of the procedure include bleeding, infection, damage to nearby structures like the parathyroid glands and recurrent laryngeal nerve, and hypoparathyroidism or hypothyroidism due to removal of or damage to the parathyroid glands or thyroid gland, respectively. Close postoperative monitoring and management are essential to minimize these risks and ensure optimal patient outcomes.

A drug interaction is the effect of combining two or more drugs, or a drug and another substance (such as food or alcohol), which can alter the effectiveness or side effects of one or both of the substances. These interactions can be categorized as follows:

1. Pharmacodynamic interactions: These occur when two or more drugs act on the same target organ or receptor, leading to an additive, synergistic, or antagonistic effect. For example, taking a sedative and an antihistamine together can result in increased drowsiness due to their combined depressant effects on the central nervous system.
2. Pharmacokinetic interactions: These occur when one drug affects the absorption, distribution, metabolism, or excretion of another drug. For example, taking certain antibiotics with grapefruit juice can increase the concentration of the antibiotic in the bloodstream, leading to potential toxicity.
3. Food-drug interactions: Some drugs may interact with specific foods, affecting their absorption, metabolism, or excretion. An example is the interaction between warfarin (a blood thinner) and green leafy vegetables, which can increase the risk of bleeding due to enhanced vitamin K absorption from the vegetables.
4. Drug-herb interactions: Some herbal supplements may interact with medications, leading to altered drug levels or increased side effects. For instance, St. John's Wort can decrease the effectiveness of certain antidepressants and oral contraceptives by inducing their metabolism.
5. Drug-alcohol interactions: Alcohol can interact with various medications, causing additive sedative effects, impaired judgment, or increased risk of liver damage. For example, combining alcohol with benzodiazepines or opioids can lead to dangerous levels of sedation and respiratory depression.

It is essential for healthcare providers and patients to be aware of potential drug interactions to minimize adverse effects and optimize treatment outcomes.

Chromatin Immunoprecipitation (ChIP) is a molecular biology technique used to analyze the interaction between proteins and DNA in the cell. It is a powerful tool for studying protein-DNA binding, such as transcription factor binding to specific DNA sequences, histone modification, and chromatin structure.

In ChIP assays, cells are first crosslinked with formaldehyde to preserve protein-DNA interactions. The chromatin is then fragmented into small pieces using sonication or other methods. Specific antibodies against the protein of interest are added to precipitate the protein-DNA complexes. After reversing the crosslinking, the DNA associated with the protein is purified and analyzed using PCR, sequencing, or microarray technologies.

ChIP assays can provide valuable information about the regulation of gene expression, epigenetic modifications, and chromatin structure in various biological processes and diseases, including cancer, development, and differentiation.

Phosphorylation is the process of adding a phosphate group (a molecule consisting of one phosphorus atom and four oxygen atoms) to a protein or other organic molecule, which is usually done by enzymes called kinases. This post-translational modification can change the function, localization, or activity of the target molecule, playing a crucial role in various cellular processes such as signal transduction, metabolism, and regulation of gene expression. Phosphorylation is reversible, and the removal of the phosphate group is facilitated by enzymes called phosphatases.

Interleukin-6 (IL-6) is a cytokine, a type of protein that plays a crucial role in communication between cells, especially in the immune system. It is produced by various cells including T-cells, B-cells, fibroblasts, and endothelial cells in response to infection, injury, or inflammation.

IL-6 has diverse effects on different cell types. In the immune system, it stimulates the growth and differentiation of B-cells into plasma cells that produce antibodies. It also promotes the activation and survival of T-cells. Moreover, IL-6 plays a role in fever induction by acting on the hypothalamus to raise body temperature during an immune response.

In addition to its functions in the immune system, IL-6 has been implicated in various physiological processes such as hematopoiesis (the formation of blood cells), bone metabolism, and neural development. However, abnormal levels of IL-6 have also been associated with several diseases, including autoimmune disorders, chronic inflammation, and cancer.

Melanosomes are membrane-bound organelles found in melanocytes, the pigment-producing cells in the skin, hair, and eyes. They contain the pigment melanin, which is responsible for giving color to these tissues. Melanosomes are produced in the melanocyte and then transferred to surrounding keratinocytes in the epidermis via a process called cytocrinesis. There are four stages of melanosome development: stage I (immature), stage II (developing), stage III (mature), and stage IV (degrading). The amount and type of melanin in the melanosomes determine the color of an individual's skin, hair, and eyes. Mutations in genes involved in melanosome biogenesis or function can lead to various pigmentation disorders, such as albinism.

Dimerization is a process in which two molecules, usually proteins or similar structures, bind together to form a larger complex. This can occur through various mechanisms, such as the formation of disulfide bonds, hydrogen bonding, or other non-covalent interactions. Dimerization can play important roles in cell signaling, enzyme function, and the regulation of gene expression.

In the context of medical research and therapy, dimerization is often studied in relation to specific proteins that are involved in diseases such as cancer. For example, some drugs have been developed to target and inhibit the dimerization of certain proteins, with the goal of disrupting their function and slowing or stopping the progression of the disease.

Calcinosis is a medical condition characterized by the abnormal deposit of calcium salts in various tissues of the body, commonly under the skin or in the muscles and tendons. These calcium deposits can form hard lumps or nodules that can cause pain, inflammation, and restricted mobility. Calcinosis can occur as a complication of other medical conditions, such as autoimmune disorders, kidney disease, and hypercalcemia (high levels of calcium in the blood). In some cases, the cause of calcinosis may be unknown. Treatment for calcinosis depends on the underlying cause and may include medications to manage calcium levels, physical therapy, and surgical removal of large deposits.

Lactones are not a medical term per se, but they are important in the field of pharmaceuticals and medicinal chemistry. Lactones are cyclic esters derived from hydroxy acids. They can be found naturally in various plants, fruits, and some insects. In medicine, lactones have been used in the synthesis of drugs, including certain antibiotics and antifungal agents. For instance, the penicillin family of antibiotics contains a beta-lactone ring in their structure, which is essential for their antibacterial activity.

Creatinine is a waste product that's produced by your muscles and removed from your body by your kidneys. Creatinine is a breakdown product of creatine, a compound found in meat and fish, as well as in the muscles of vertebrates, including humans.

In healthy individuals, the kidneys filter out most of the creatinine and eliminate it through urine. However, when the kidneys are not functioning properly, creatinine levels in the blood can rise. Therefore, measuring the amount of creatinine in the blood or urine is a common way to test how well the kidneys are working. High creatinine levels in the blood may indicate kidney damage or kidney disease.

Molecular weight, also known as molecular mass, is the mass of a molecule. It is expressed in units of atomic mass units (amu) or daltons (Da). Molecular weight is calculated by adding up the atomic weights of each atom in a molecule. It is a useful property in chemistry and biology, as it can be used to determine the concentration of a substance in a solution, or to calculate the amount of a substance that will react with another in a chemical reaction.

Flow cytometry is a medical and research technique used to measure physical and chemical characteristics of cells or particles, one cell at a time, as they flow in a fluid stream through a beam of light. The properties measured include:

* Cell size (light scatter)
* Cell internal complexity (granularity, also light scatter)
* Presence or absence of specific proteins or other molecules on the cell surface or inside the cell (using fluorescent antibodies or other fluorescent probes)

The technique is widely used in cell counting, cell sorting, protein engineering, biomarker discovery and monitoring disease progression, particularly in hematology, immunology, and cancer research.

Autoimmune encephalomyelitis (EAE) is a model of inflammatory demyelinating disease used in medical research to study the mechanisms of multiple sclerosis (MS) and develop new therapies. It is experimentally induced in laboratory animals, typically mice or rats, through immunization with myelin antigens or T-cell transfer. The resulting immune response leads to inflammation, demyelination, and neurological dysfunction in the central nervous system (CNS), mimicking certain aspects of MS.

EAE is a valuable tool for understanding the pathogenesis of MS and testing potential treatments. However, it is essential to recognize that EAE is an experimental model and may not fully recapitulate all features of human autoimmune encephalomyelitis.

Immunohistochemistry (IHC) is a technique used in pathology and laboratory medicine to identify specific proteins or antigens in tissue sections. It combines the principles of immunology and histology to detect the presence and location of these target molecules within cells and tissues. This technique utilizes antibodies that are specific to the protein or antigen of interest, which are then tagged with a detection system such as a chromogen or fluorophore. The stained tissue sections can be examined under a microscope, allowing for the visualization and analysis of the distribution and expression patterns of the target molecule in the context of the tissue architecture. Immunohistochemistry is widely used in diagnostic pathology to help identify various diseases, including cancer, infectious diseases, and immune-mediated disorders.

Sodium-phosphate cotransporter proteins are membrane transport proteins that facilitate the active transport of sodium and inorganic phosphate ions across biological membranes. These proteins play a crucial role in maintaining phosphate homeostasis within the body by regulating the absorption and excretion of phosphate in the kidneys and intestines. They exist in two major types, type I (NaPi-I) and type II (NaPi-II), each having multiple subtypes with distinct tissue distributions and regulatory mechanisms.

Type I sodium-phosphate cotransporters are primarily expressed in the kidney's proximal tubules and play a significant role in reabsorbing phosphate from the primary urine back into the bloodstream. Type II sodium-phosphate cotransporters, on the other hand, are found in both the kidneys and intestines. In the kidneys, they contribute to phosphate reabsorption, while in the intestines, they facilitate phosphate absorption from food.

These proteins function by coupling the passive downhill movement of sodium ions (driven by the electrochemical gradient) with the active uphill transport of phosphate ions against their concentration gradient. This coupled transport process enables cells to maintain intracellular phosphate concentrations within a narrow range, despite fluctuations in dietary intake and renal function.

Dysregulation of sodium-phosphate cotransporter proteins has been implicated in various pathological conditions, such as chronic kidney disease (CKD), tumoral calcinosis, and certain genetic disorders affecting phosphate homeostasis.

'Cercopithecus aethiops' is the scientific name for the monkey species more commonly known as the green monkey. It belongs to the family Cercopithecidae and is native to western Africa. The green monkey is omnivorous, with a diet that includes fruits, nuts, seeds, insects, and small vertebrates. They are known for their distinctive greenish-brown fur and long tail. Green monkeys are also important animal models in biomedical research due to their susceptibility to certain diseases, such as SIV (simian immunodeficiency virus), which is closely related to HIV.

Kidney disease, also known as nephropathy or renal disease, refers to any functional or structural damage to the kidneys that impairs their ability to filter blood, regulate electrolytes, produce hormones, and maintain fluid balance. This damage can result from a wide range of causes, including diabetes, hypertension, glomerulonephritis, polycystic kidney disease, lupus, infections, drugs, toxins, and congenital or inherited disorders.

Depending on the severity and progression of the kidney damage, kidney diseases can be classified into two main categories: acute kidney injury (AKI) and chronic kidney disease (CKD). AKI is a sudden and often reversible loss of kidney function that occurs over hours to days, while CKD is a progressive and irreversible decline in kidney function that develops over months or years.

Symptoms of kidney diseases may include edema, proteinuria, hematuria, hypertension, electrolyte imbalances, metabolic acidosis, anemia, and decreased urine output. Treatment options depend on the underlying cause and severity of the disease and may include medications, dietary modifications, dialysis, or kidney transplantation.

Cartilage is a type of connective tissue that is found throughout the body in various forms. It is made up of specialized cells called chondrocytes, which are embedded in a firm, flexible matrix composed of collagen fibers and proteoglycans. This unique structure gives cartilage its characteristic properties of being both strong and flexible.

There are three main types of cartilage in the human body: hyaline cartilage, elastic cartilage, and fibrocartilage.

1. Hyaline cartilage is the most common type and is found in areas such as the articular surfaces of bones (where they meet to form joints), the nose, trachea, and larynx. It has a smooth, glassy appearance and provides a smooth, lubricated surface for joint movement.
2. Elastic cartilage contains more elastin fibers than hyaline cartilage, which gives it greater flexibility and resilience. It is found in structures such as the external ear and parts of the larynx and epiglottis.
3. Fibrocartilage has a higher proportion of collagen fibers and fewer chondrocytes than hyaline or elastic cartilage. It is found in areas that require high tensile strength, such as the intervertebral discs, menisci (found in joints like the knee), and the pubic symphysis.

Cartilage plays a crucial role in supporting and protecting various structures within the body, allowing for smooth movement and providing a cushion between bones to absorb shock and prevent wear and tear. However, cartilage has limited capacity for self-repair and regeneration, making damage or degeneration of cartilage tissue a significant concern in conditions such as osteoarthritis.

A radioligand assay is a type of in vitro binding assay used in molecular biology and pharmacology to measure the affinity and quantity of a ligand (such as a drug or hormone) to its specific receptor. In this technique, a small amount of a radioactively labeled ligand, also known as a radioligand, is introduced to a sample containing the receptor of interest. The radioligand binds competitively with other unlabeled ligands present in the sample for the same binding site on the receptor. After allowing sufficient time for binding, the reaction is stopped, and the amount of bound radioligand is measured using a technique such as scintillation counting. The data obtained from this assay can be used to determine the dissociation constant (Kd) and maximum binding capacity (Bmax) of the receptor-ligand interaction, which are important parameters in understanding the pharmacological properties of drugs and other ligands.

Butyric acid is a type of short-chain fatty acid that is naturally produced in the human body through the fermentation of dietary fiber in the colon. Its chemical formula is C4H8O2. It has a distinctive, rancid odor and is used in the production of perfumes, flavorings, and certain types of plasticizers. In addition to its natural occurrence in the human body, butyric acid is also found in some foods such as butter, parmesan cheese, and fermented foods like sauerkraut. It has been studied for its potential health benefits, including its role in gut health, immune function, and cancer prevention.

Osteogenesis is the process of bone formation or development. It involves the differentiation and maturation of osteoblasts, which are bone-forming cells that synthesize and deposit the organic matrix of bone tissue, composed mainly of type I collagen. This organic matrix later mineralizes to form the inorganic crystalline component of bone, primarily hydroxyapatite.

There are two primary types of osteogenesis: intramembranous and endochondral. Intramembranous osteogenesis occurs directly within connective tissue, where mesenchymal stem cells differentiate into osteoblasts and form bone tissue without an intervening cartilage template. This process is responsible for the formation of flat bones like the skull and clavicles.

Endochondral osteogenesis, on the other hand, involves the initial development of a cartilaginous model or template, which is later replaced by bone tissue. This process forms long bones, such as those in the limbs, and occurs through several stages involving chondrocyte proliferation, hypertrophy, and calcification, followed by invasion of blood vessels and osteoblasts to replace the cartilage with bone tissue.

Abnormalities in osteogenesis can lead to various skeletal disorders and diseases, such as osteogenesis imperfecta (brittle bone disease), achondroplasia (a form of dwarfism), and cleidocranial dysplasia (a disorder affecting skull and collarbone development).

Regulatory sequences in nucleic acid refer to specific DNA or RNA segments that control the spatial and temporal expression of genes without encoding proteins. They are crucial for the proper functioning of cells as they regulate various cellular processes such as transcription, translation, mRNA stability, and localization. Regulatory sequences can be found in both coding and non-coding regions of DNA or RNA.

Some common types of regulatory sequences in nucleic acid include:

1. Promoters: DNA sequences typically located upstream of the gene that provide a binding site for RNA polymerase and transcription factors to initiate transcription.
2. Enhancers: DNA sequences, often located at a distance from the gene, that enhance transcription by binding to specific transcription factors and increasing the recruitment of RNA polymerase.
3. Silencers: DNA sequences that repress transcription by binding to specific proteins that inhibit the recruitment of RNA polymerase or promote chromatin compaction.
4. Intron splice sites: Specific nucleotide sequences within introns (non-coding regions) that mark the boundaries between exons (coding regions) and are essential for correct splicing of pre-mRNA.
5. 5' untranslated regions (UTRs): Regions located at the 5' end of an mRNA molecule that contain regulatory elements affecting translation efficiency, stability, and localization.
6. 3' untranslated regions (UTRs): Regions located at the 3' end of an mRNA molecule that contain regulatory elements influencing translation termination, stability, and localization.
7. miRNA target sites: Specific sequences in mRNAs that bind to microRNAs (miRNAs) leading to translational repression or degradation of the target mRNA.

Small interfering RNA (siRNA) is a type of short, double-stranded RNA molecule that plays a role in the RNA interference (RNAi) pathway. The RNAi pathway is a natural cellular process that regulates gene expression by targeting and destroying specific messenger RNA (mRNA) molecules, thereby preventing the translation of those mRNAs into proteins.

SiRNAs are typically 20-25 base pairs in length and are generated from longer double-stranded RNA precursors called hairpin RNAs or dsRNAs by an enzyme called Dicer. Once generated, siRNAs associate with a protein complex called the RNA-induced silencing complex (RISC), which uses one strand of the siRNA (the guide strand) to recognize and bind to complementary sequences in the target mRNA. The RISC then cleaves the target mRNA, leading to its degradation and the inhibition of protein synthesis.

SiRNAs have emerged as a powerful tool for studying gene function and have shown promise as therapeutic agents for a variety of diseases, including viral infections, cancer, and genetic disorders. However, their use as therapeutics is still in the early stages of development, and there are challenges associated with delivering siRNAs to specific cells and tissues in the body.

Kidney tubules are the structural and functional units of the kidney responsible for reabsorption, secretion, and excretion of various substances. They are part of the nephron, which is the basic unit of the kidney's filtration and reabsorption process.

There are three main types of kidney tubules:

1. Proximal tubule: This is the initial segment of the kidney tubule that receives the filtrate from the glomerulus. It is responsible for reabsorbing approximately 65% of the filtrate, including water, glucose, amino acids, and electrolytes.
2. Loop of Henle: This U-shaped segment of the tubule consists of a thin descending limb, a thin ascending limb, and a thick ascending limb. The loop of Henle helps to concentrate urine by creating an osmotic gradient that allows water to be reabsorbed in the collecting ducts.
3. Distal tubule: This is the final segment of the kidney tubule before it empties into the collecting duct. It is responsible for fine-tuning the concentration of electrolytes and pH balance in the urine by selectively reabsorbing or secreting substances such as sodium, potassium, chloride, and hydrogen ions.

Overall, kidney tubules play a critical role in maintaining fluid and electrolyte balance, regulating acid-base balance, and removing waste products from the body.

Protein biosynthesis is the process by which cells generate new proteins. It involves two major steps: transcription and translation. Transcription is the process of creating a complementary RNA copy of a sequence of DNA. This RNA copy, or messenger RNA (mRNA), carries the genetic information to the site of protein synthesis, the ribosome. During translation, the mRNA is read by transfer RNA (tRNA) molecules, which bring specific amino acids to the ribosome based on the sequence of nucleotides in the mRNA. The ribosome then links these amino acids together in the correct order to form a polypeptide chain, which may then fold into a functional protein. Protein biosynthesis is essential for the growth and maintenance of all living organisms.

Fc receptors (FcRs) are specialized proteins found on the surface of various immune cells, including neutrophils, monocytes, macrophages, eosinophils, basophils, mast cells, and B lymphocytes. They play a crucial role in the immune response by recognizing and binding to the Fc region of antibodies (IgG, IgA, and IgE) after they have interacted with their specific antigens.

FcRs can be classified into several types based on the class of antibody they bind:

1. FcγRs - bind to the Fc region of IgG antibodies
2. FcαRs - bind to the Fc region of IgA antibodies
3. FcεRs - bind to the Fc region of IgE antibodies

The binding of antibodies to Fc receptors triggers various cellular responses, such as phagocytosis, degranulation, and antibody-dependent cellular cytotoxicity (ADCC), which contribute to the elimination of pathogens, immune complexes, and other foreign substances. Dysregulation of Fc receptor function has been implicated in several diseases, including autoimmune disorders and allergies.

Cytochrome P450 family 24 subfamily A member 1 (abbreviated CYP24A1) is a member of the cytochrome P450 superfamily of enzymes ... 62 (4): 192-3. doi:10.1159/000133473. PMID 8440135. Chen KS, Prahl JM, DeLuca HF (May 1993). "Isolation and expression of human ... Transcription of the CYP24A1 gene is markedly inducible by 1,25-(OH)2D3 binding to the vitamin D receptor. The gene has a ... CYP24A1 was identified in the early 1970s and was first thought to be involved in vitamin D metabolism as the renal 25- ...
100 (3): 862-8. doi:10.1182/blood-2002-01-0220. PMID 12130496. Schiedlmeier B, Klump H, Will E, Arman-Kalcek G, Li Z, Wang Z, ... 14 (3): 419-24. PMID 10904875. Giannola DM, Shlomchik WD, Jegathesan M, Liebowitz D, Abrams CS, Kadesch T, Dancis A, Emerson SG ... 40 (3): 191-7. doi:10.1111/j.1432-0436.1989.tb00598.x. PMID 2570724. Acampora D, D'Esposito M, Faiella A, Pannese M, Migliaccio ... 17 (24): 10385-402. doi:10.1093/nar/17.24.10385. PMC 335308. PMID 2574852. Boncinelli E, Acampora D, Pannese M, D'Esposito M, ...
25-hydroxyvitamin d 2 MeSH D10.570.938.590 - lanosterol MeSH D10.627.430.354 - cod liver oil MeSH D10.627.430.450 - fatty acids ... omega-3 MeSH D10.212.302.380.410.100 - alpha-linolenic acid MeSH D10.212.302.380.410.210 - docosahexaenoic acids MeSH D10.212. ... omega-3 MeSH D10.251.355.337.100 - alpha-linolenic acid MeSH D10.251.355.337.250 - docosahexaenoic acids MeSH D10.251.355.337. ... 24,25-dihydroxyvitamin d 3 MeSH D10.570.938.208 - cholesterol MeSH D10.570.938.208.070 - azacosterol MeSH D10.570.938.208.160 ...
25-hydroxyvitamin d 2 MeSH D04.808.247.808.489 - fusidic acid MeSH D04.808.247.808.607 - lanosterol MeSH D04.808.247.808.756 - ... vitamin k 3 MeSH D04.615.638.845 - 1-naphthylamine MeSH D04.615.638.845.800 - sertraline MeSH D04.615.638.850 - 2-naphthylamine ... 25-dihydroxyvitamin d 3 MeSH D04.808.247.808.197 - cholesterol MeSH D04.808.247.808.197.070 - azacosterol MeSH D04.808.247.808. ... 25-hydroxyvitamin d 2 MeSH D04.808.247.222.537 - ergosterol MeSH D04.808.247.222.857 - sitosterols MeSH D04.808.247.808 - ...
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Hodkinson and Pyrah proposed hypercalciuria as a calcium excretion of over 7.5 mmol in men and 6.25 mmol in women, every 24 ... If calcium excreted in urine is measured to be lower than 0.07 mmol/kg after 24 hours, diet-dependent hypercalciuria can be ... Excessive vitamin D intake can lead to an overexpression of vitamin D receptors (VDR) causing an elevated serum level of 1,25- ... dihydroxyvitamin D3 [1,25(OH)2D3], or calcitriol. An elevated level of 1,25-dihydroxyvitamin D3 stimulates more absorption of ...
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Over 3% of the population exceeds the NIH daily tolerable upper intake level (UL) of 4000 IU, above which level the risk of ... Low blood calcifediol (25-hydroxy-vitamin D) can result from avoiding the sun. Being deficient in Vitamin D can cause the ... 4 (3): 208-30. doi:10.3390/nu4030208. PMC 3347028. PMID 22666547. Bi WG, Nuyt AM, Weiler H, Leduc L, Santamaria C, Wei SQ (July ... The high 25(OH)D concentrations, and relatively high vitamin D requirements of apes and monkeys are understandable in light of ...
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The CYP24A1 gene provides instructions for making an enzyme called 24-hydroxylase. Learn about this gene and related health ... dihydroxyvitamin D3 24-hydroxylase. *1,25-dihydroxyvitamin D(3) 24-hydroxylase, mitochondrial isoform 1 precursor ... cytochrome P450, subfamily XXIV (vitamin D 24-hydroxylase). *cytochrome P450-CC24. *exo-mitochondrial protein ... 2017 Aug;58(3):349-353. doi: 10.1007/s13353-017-0397-2. Epub 2017 May 3. Citation on PubMed or Free article on PubMed Central ...
Deuterated 1-α25-Dihydroxyvitamin D3 solution. Empirical Formula (Hill Notation). : C27D3H41O3. CAS No.. : 128723-16-0. ... 3-epi-25-Hydroxyvitamin D3 (6,19,19-d3) solution. Empirical Formula (Hill Notation). : C27D3H41O2. Molecular Weight. : 403.66. ... 1,25-Dihydroxyvitamin D3-13C3 (25,26,27-13C3) solution. Empirical Formula (Hill Notation). : 13C3C24H44O3. Molecular Weight. : ... Vitamin D3(6,19,19-d3) solution. Synonym(s). : Calciol (6,19,19-d3) solution, Cholecalciferol (6,19,19-d3) solution ...
Cytochrome P450 family 24 subfamily A member 1 (abbreviated CYP24A1) is a member of the cytochrome P450 superfamily of enzymes ... 62 (4): 192-3. doi:10.1159/000133473. PMID 8440135. Chen KS, Prahl JM, DeLuca HF (May 1993). "Isolation and expression of human ... Transcription of the CYP24A1 gene is markedly inducible by 1,25-(OH)2D3 binding to the vitamin D receptor. The gene has a ... CYP24A1 was identified in the early 1970s and was first thought to be involved in vitamin D metabolism as the renal 25- ...
Simultaneous Quantification of 25-Hydroxyvitamin D3 and 24,25-Dihydroxyvitamin D3 in Rats Shows Strong Correlations between ...
58(3):528-536.. Lowry MB, Guo C, Zhang Y, Fantacone ML, Logan IE, Campbell Y, Zhang W, Le M, Indra AK, Ganguli-Indra G et al.. ... 58(3):528-536.. Guo C, Gombart AF. 2014. The antibiotic effects of vitamin D.. Endocr Metab Immune Disord Drug Targets. 14(4): ... 24(5):754-9.. Lowry MB, Guo C, Borregaard N, Gombart AF. 2014. Regulation of the human cathelicidin antimicrobial peptide gene ... Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells.. J ...
2022 Apr 24;11(9):2387. doi: 10.3390/jcm11092387. J Clin Med. 2022. PMID: 35566512 Free PMC article. Review. ... 2007 Mar;320(3):1119-26. doi: 10.1124/jpet.106.115451. Epub 2006 Dec 20. J Pharmacol Exp Ther. 2007. PMID: 17182978 ... 1994;4(3):223-5. doi: 10.3233/WOR-1994-4312. Work. 1994. PMID: 24440957 No abstract available. ... 1993;3(1):76-7. doi: 10.3233/WOR-1993-3114. Work. 1993. PMID: 24441966 No abstract available. ...
In one, [3H]24,25(OH)2D3 production reached 2.9 pmol/106 cells per 30 min at 10-6 M 1,25(OH)2D3 (30% normal maximum at 10-6 M 1 ... 24-OHase induction was detectable in normal fibroblasts at ~3 x 10-10 M 1,25(OH)2D3. [3H]24,25(OH)2D3 formation after exposure ... Apparent maximal [3H]24,25(OH)2D3 production in normal cell lines was 9 pmol/106 cells per 30 min and occurred after induction ... In one, [3H]24,25(OH)2D3 production reached 2.9 pmol/106 cells per 30 min at 10-6 M 1,25(OH)2D3 (30% normal maximum at 10-6 M 1 ...
Type 3 transporters were initially identified as viral transport proteins. Almost all cells express type 3 sodium phosphate ... FGF23 production by osteoblasts is stimulated by 1,25 vitamin D. [8] Conversely, individuals with X-linked hypophosphatemic ... As levels of 1,25 vitamin D fall during the development of progressive chronic kidney disease, levels of FGF23 rise inversely. ... Excess free serum phosphate is taken up into vascular smooth muscle via a type 3 sodium-phosphate cotransporter. The increased ...
Diurnal rhythm of plasma 1,25-dihydroxyvitamin D and vitamin D-binding protein in postmenopausal women: relationship to plasma ... Calcif Tissue Res 1977 Oct 20;23(3):241-4. Proliferation of osteoclasts in rat bone following bleeding and femoral fractures. ... Proc Soc Exp Biol Med 1986 Mar;181(3):438-42. Forskolin-induced bone resorption in neonatal mouse calvaria in vitro. ... bone) to PTH and 1,25(OH)2 vitamin D3, Under certain conditions however, magnesium can stimulate bone resorption. A more potent ...
2004 Mar;79(3):362-71.. Hypponen E, Laara E, Reunanen A, Jarvelin MR, Virtanen SM. Intake of vitamin D and risk of type 1 ... 2009 Jul;17(3):703-17.. Melamed ML, Michos ED, Post W, Astor B. 25-hydroxyvitamin D levels and the risk of mortality in the ... 2008;25(6):539-43.. Pfeifer M, Begerow B, Minne HW, Nachtigall D, Hansen C. Effects of a short-term vitamin D(3) and calcium ... 2000;72(3):690-3.. Yin L, Raum E, Haug U, Arndt V, Brenner H. Meta-analysis of longitudinal studies: Serum vitamin D and ...
2004 Mar;79(3):362-71.. Hypponen E, Laara E, Reunanen A, Jarvelin MR, Virtanen SM. Intake of vitamin D and risk of type 1 ... 2009 Jul;17(3):703-17.. Melamed ML, Michos ED, Post W, Astor B. 25-hydroxyvitamin D levels and the risk of mortality in the ... 2008;25(6):539-43.. Pfeifer M, Begerow B, Minne HW, Nachtigall D, Hansen C. Effects of a short-term vitamin D(3) and calcium ... 2000;72(3):690-3.. Yin L, Raum E, Haug U, Arndt V, Brenner H. Meta-analysis of longitudinal studies: Serum vitamin D and ...
We hypothesized that catabolism of 25(OH)D3 to 24,25(OH)2D3 would be greater in the bolus than in the daily dose group. Design ... Greater breast milk vitamin D3 values in the single dose group were inversely associated with the 24,25(OH)2D3/25(OH)D3 ratio ( ... Results: The concentration of serum 24,25(OH)2D3 was directly related to that of 25(OH)D in both groups (r2 = 0.63; p , 0.001 ... A daily dose of vitamin D may have more lasting effectiveness in increasing 25(OH)D3 with lesser diversion of 25(OH)D3 to 24,25 ...
This means that the time earlier than complete re?titration is critical due to this fact varies between 3 and 7 days, relying ... J Clin Psychopharmacol 33(3):329-335, 2013 23609380 Bitter I, Katona L, Zambori J, et al: Comparative effectiveness of depot ... Accordingly, the metabolic alterations allowing biosynthesis of p-toluate, terephthalate or (2-hydroxy-3-methyl-4-oxobutoxy) ... Function: Dorsiflexion (1); extengroup 3: (1) Pyriformis; (2) gemellus (superior or sion of toes (2); stabilization of arch (3 ...
Anti-inflammatory effect of 1,25dihydroxyvitamin D (3) is associated with crosstalk between signal transducer and activator of ... 1,25(OH)D, 1,25-hydroxyvitamin D or calcitriol; 25OHD, 25-hydroxyvitamin D; BMI, body mass index; CRP, C -reactive protein; IL, ... The 1,25(OH)D has been shown to exert anti-proliferative effects on keratinocytes [16]. Numerous in vitro and in vivo studies ... 93] found that, in eggs boiled for 10 min, the vitamin D3 concentration was 1-6% lower and 25(OH)-D-3 content was 6-11% lower ...
1,25-(OH)2-D3 has also been found to enhance the activity of some vitamin D-receptor positive immune cells and to enhance the ... 32222-06-3. InChI Key. GMRQFYUYWCNGIN-NKMMMXOESA-N. InChI. InChI=1S/C27H44O3/c1-18(8-6-14-26(3,4)30)23-12-13-24-20(9-7-15-27(23 ... 1,25-(OH)2-D3 has demonstrated beneficial effects in animal models of such autoimmune diseases as rheumatoid arthritis. Vitamin ... Ohter identified metabolites of calcitriol include 1α, 25(OH)2-24-oxo-D3; 1α, 23,25(OH)3-24-oxo-D3; 1α, 24R,25(OH)3D3; 1α, 25S, ...
"Dihydroxyvitamin D" OR "Dihidroxivitamina D" OR "Dihidroxivitaminas D" OR "Di-Hidroxivitamina D" OR "Di-Hidroxivitaminas D" OR ... "24,25-Di-Hidroxivitamina D 3" OR ((3beta,5Z,7E)-9,10-Secocholesta-5,7,10(19)-trien-3-ol) OR "25(OH)D" OR "1,25 Hydroxyvitamin" ... OR "1,25 Hidroxivitamin" OR "1-25 Hydroxyvitamin" OR "1-25 Hidroxivitamin" OR "1,25(OH)D" OR "1-25(OH)D" OR Calciol OR ... 25-Dihydroxyvitamin D 3" OR mh:"Vitamin D Deficiency" OR tw:("Vitamin D" OR "Vitamina D" OR Cholecalciferol OR Colecalciferol ...
Fri Apr 24 00:00:00 EDT 2020. Influenza NG-34 T cell conserved epitope adjuvanted with CAF01 as a possible influenza vaccine ... Wed Nov 24 00:00:00 EST 2010. 1,25-Dihydroxyvitamin D3 inhibits the differentiation and migration of T(H)17 cells to protect ... Tue Nov 24 00:00:00 EST 2020. IL-17A-producing T cells exacerbate fine particulate matter-induced lung inflammation and ... Tue May 25 00:00:00 EDT 2021. M1 Macrophage Derived Exosomes Aggravate Experimental Autoimmune Neuritis via Modulating Th1 ...
When calcipotriene was applied topically to mice for up to 24 months at dosages of 3, 10 and 30 µg/kg/day (corresponding to 9 ... The active form of the vitamin, 1,25-dihydroxy vitamin D3 (calcitriol), is known to be recycled via the liver and excreted in ... There is evidence that maternal 1,25-dihydroxy vitamin D3 (calcitriol) may enter the fetal circulation, but it is not known ... Chemically, calcipotriene is (5Z,7E,22E,24S)-24-cyclopropyl-9,10-secochola-5,7,10(19), 22-tetraene-1α,3β,24-triol-, with the ...
We found a significant fall in the level of 1,25-dihydroxyvitamin D (p less than 0.01) and a significant increase in the molar ... The authors report 3 patients affected by psoriasiform acral dermatitis, a distinctive clinical entity characterized by a ... The effects of one weeks daily treatment with dexchlorpheniramine (3 + 3 mg x 2) and loratadine (10 mg x 2) on the cutaneous ... Indomethacin and piroxicam markedly inhibited the erythema at 6 to 24 h after irradiation but erythema reappeared at 45 h. The ...
24,24-difluoro-9,10-secocholesta-5,7,10-triene-1,3,25-triol (C27H42F2O3) from the PQR. ... C27H42F2O3. IUPAC Name. (3z)-3-[(2e)-2-[(1r,3as,7ar)-1-[(1r)-4,4-difluoro-5-hydroxy-1,5-dimethyl-hexyl]-7a-methyl-2,3,3a,5,6,7- ... 1R,3S,5Z,7E)-24,24-Difluoro-9,10-Secocholesta-5,7,10-Triene-1,3,25-Triol ... 1s,3r,5z)-5-[(2e)-2-[(1r,3as,7ar)-1-[(1r)-4,4-difluoro-5-hydroxy-1,5-dimethyl-hexyl]-7a-methyl-2,3,3a,5,6,7-hexahydro-1h-inden- ...
... dihydroxyvitamin D(3) 24‐hydroxylase; CX32, gap junction connexin‐32.2 protein; CYLC1, cylicin‐1; Dio1; DSC1, desmocollin‐1; ... dihydroxyvitamin D(3) 24‐hydroxylase; CX32, gap junction connexin‐32.2 protein; CYLC1, cylicin‐1; Dio1; DSC1, desmocollin‐1; ... Gene names are as follows: "14.3.3.a, 14‐33.a protein; APOC1, apolipoprotein C‐I; APOM, apolipoprotein M; AQP‐3, aquaporin‐3; ... Gene names are as follows: "14.3.3.a, 14‐33.a protein; APOC1, apolipoprotein C‐I; APOM, apolipoprotein M; AQP‐3, aquaporin‐3; ...
Project Title: 24,25-Dihydroxyvitamin D in CRIC. UWashington PI: KESTENBAUM. Start: 4/1/2016. End: 3/31/2020. Project Title: ... End: 3/31/2028. Project Title: Development of a Kidney Biomarker Panel to Detect and Quantify NSAID Damage among Persons with ... End: 3/31/2023. Project Title: The role of iron deficiency in cardiac and diabetic complications of CKD ... End: 3/31/2016. Project Title: Validation of the Kidney Knowledge Survey (KIKS) in Hispanics with CKD ...
doi:10.1007/978-3-642-10858-7_13. *Chen P, Hu P, Xie D, Qin Y, Wang F, Wang H. Meta-analysis of vitamin D, calcium and the ... The half-life of 1,25(OH)2D is only 4 to 6 hours and 1000-fold less than the total 25(OH)D. So, serum vitamin D is usually ... He showed that 25(OH)D concentration values are only useful for short follow-up times for breast cancer as it develops rapidly ... The 25(OH)D is then transported in the circulation by the vitamin D-binding protein and further metabolized in kidneys to ...
... dihydroxy vitamin D3 on the expressions of vascular endothelial growth factor and transforming growth factor-b1 in the retinas ... Dihydroxyvitamin D3, an inducer of glial cell line-derived neurotrophic factor. NeuroReport. 1996;7(13):2171-5. v1996 ... 24. ; Intervention 56. ; Meta-analysis 38. ; Obesity 34. ; Pregnancy 43. ; T1 (child) 39. ; Omega-3 11. ; Vitamin D Receptor 23 ... 2013;44(3):235-41 CrossRefGoogle Scholar *10 Pilz S, Kienreich K, Rutters F, et al. Role of vitamin D in the development of ...
It is best not to let puppies or kittens nurse for 12-24 hours after the bitch or queen is treated for hypocalcemia. During ... After the acute crisis, elemental calcium at 25-50 mg/kg per day orally in three or four divided doses is given for the ... The dosage of 1,25-dihydroxyvitamin D3 (calcitriol) is 0.03-0.06 mcg/kg per day. Calcitriol has a rapid onset of action (1-4 ... This is a much briefer period than that observed with the use of dihydrotachysterol (1-3 weeks) or ergocalciferol (vitamin D2; ...
Dihydroxyvitamin D3 modifies cyclosporine-induced bone loss. Calcif Tissue Int. 1990 Sep;. 47(3): 152-7.. 5. Adinoff A, ... Vitamin D, 25-OH vitamin D, and 1,25-(OH)2 vitamin D were. reported to increase BMD in GC-treated patients, but other studies ... 3. Movsowitz C, Epstein S, Fallon M, Ismail F, Thomas S. Cyclosporin-A in vivo produces. severe osteopenia in the rat: effect ... 25. Lane NE, Sanchez S, Modin GW, Genant HK, Pierini E, Arnaud CD. Bone mass continues. to increase at the hip after ...
Elevated 1, 25-dihydroxyvitamin D levels are associated with protracted treatment in sarcoidosis. In one study, serum 1, 25- ... dihydroxyvitamin D levels were associated with patients requiring repeated regimens of systemic immunosuppressive therapy or ... Correlation between 25-hydroxyvitamin D3 1 alpha-hydroxylase gene expression in alveolar macrophages and the activity of ... Kavathia D, Buckley JD, Rao D, Rybicki B, Burke R. Elevated 1, 25-dihydroxyvitamin D levels are associated with protracted ...
Prostate 18 (3): 243-54, 1991.. * Kondo Y, Homma Y, Aso Y, et al.: Promotional effect of two-generation exposure to a high-fat ... 3. ] The lifetime risk of being diagnosed with prostate cancer for U.S. men is 12.9%, while the lifetime risk of dying from ... Dioxin (2,3,7,8 tetrachlorodibenzo-p-dioxin or TCDD) is a contaminant of an herbicide used in Vietnam. This agent is similar to ... Mol Endocrinol 3 (10): 1515-22, 1989.. * Andriole GL, Bostwick DG, Brawley OW, et al.: Effect of dutasteride on the risk of ...
Fatty Acids, Omega-3. Calder PC, Carr AC, Gombart AF, Eggersdorfer M. 2020. Optimal Nutritional Status for a Well-Functioning ... 58(3):528-536.. Lowry MB, Guo C, Borregaard N, Gombart AF. 2014. Regulation of the human cathelicidin antimicrobial peptide ... Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells.. J ... 25-dihydroxyvitamin D3 in primary immune cells.. J Steroid Biochem Mol Biol. 143:183-91. ...
2014;38(3-4):244-52.. 7. Song Y, Manson JE, Cook NR, Albert CM, Buring JE, Liu S. Dietary magnesium intake and risk of ... 1994 Dec;7(3-4):169-78.. 15. Risco F, Traba ML. Influence of magnesium on the in vitro synthesis of 24,25-dihydroxyvitamin D3 ... 2016;155(3):402-10.. 24. Haq A,Svobodova J, Imran S, Stanford C, Razzaque MS. Vitamin D deficiency: a single centre analysis of ... 3. Volpe SL. 2012. Magnesium. In J. W. Erdman, Jr., I. A. Macdonald, S. H. Zeisel (Eds.), Present knowledge in nutrition (10th ...
  • The 24-hydroxylase enzyme breaks down the active form of vitamin D, called 1,25-dihydroxyvitamin D 3 or calcitriol, to an inactive form when the vitamin is no longer needed. (medlineplus.gov)
  • It is a mitochondrial monooxygenase which catalyzes reactions including 24-hydroxylation of calcitriol (1,25-dihydroxyvitamin D3). (wikipedia.org)
  • Calcitriol is an active metabolite of vitamin D with 3 hydroxyl (OH) groups and is commonly referred to as 1,25-dihydroxycholecalciferol, or 1alpha,25-dihydroxyvitamin D 3 , 1,25-dihydroxyvitamin D 3 . (drugbank.com)
  • In addition to promoting fatty acid synthesis and inhibiting lipolysis, calcitriol has been demonstrated to increase energy efficiency by suppressing UCP2 expression, which is modulated by signaling pathways of classical nuclear receptors (nVDR), where calcitriol acts as a natural ligand 3 . (drugbank.com)
  • As an active form of vitamin D 3 , calcitriol elevates the plasma levels of calcium by stimulating intestinal calcium uptake, increasing reabsorption of calcium by the kidneys, and possibly increasing the release of calcium from skeletal stores. (drugbank.com)
  • The duration of pharmacologic activity of a single dose of exogenous calcitriol is expected to be about 3 to 5 days Label . (drugbank.com)
  • The 25(OH)D is then transported in the circulation by the vitamin D-binding protein and further metabolized in kidneys to produce 1,25 dihydroxyvitamin D (1,25(OH)2D) (by 101-hydroxylase that is encoded by CYP27B1) or calcitriol. (vitamindwiki.com)
  • The CYP24A1 gene provides instructions for making an enzyme called 24-hydroxylase. (medlineplus.gov)
  • The CYP24A1 gene mutations that cause infantile hypercalcemia 1 reduce or eliminate the activity of the 24-hydroxylase enzyme. (medlineplus.gov)
  • Loss-of-function mutations of CYP24A1, the vitamin D 24-hydroxylase gene, cause long-standing hypercalciuric nephrolithiasis and nephrocalcinosis. (medlineplus.gov)
  • 1,25-(OH)2D-24 Hydroxylase (CYP24A1) Deficiency as a Cause of Nephrolithiasis. (medlineplus.gov)
  • Cytochrome P450 family 24 subfamily A member 1 (abbreviated CYP24A1) is a member of the cytochrome P450 superfamily of enzymes encoded by the CYP24A1 gene. (wikipedia.org)
  • CYP24A1 also is able to catalyse another pathway which starts with 23-hydroxylation of 1,25-(OH)2D3 and culminates in 1,25-(OH)2D3-26,23-lactone. (wikipedia.org)
  • The side chains of the ergocalciferol (vitamin D2) derivatives, 25-OH-D2 and 1,25-(OH)2D2, are also hydroxylated by CYP24A1. (wikipedia.org)
  • Transcription of the CYP24A1 gene is markedly inducible by 1,25-(OH)2D3 binding to the vitamin D receptor. (wikipedia.org)
  • Through regulation of CYP24A1 expression, a negative feedback control system is created to limit the effects of 1,25-(OH)2D3. (wikipedia.org)
  • Conclusions: After a 14-day lag, a single high dose of vitamin D led to greater production of 24,25(OH) 2 D 3 , presumably via induction of the 24-hydroxylase enzyme (CYP24A1), relative to the 25(OH)D 3 value than did daily vitamin D supplementation, and this effect persisted for at least 28 days after vitamin D administration. (elsevierpure.com)
  • Both forms undergo hydroxylation in the liver by mitochondrial and microsomal 24-hydroxylase (encoded by CYP24A1) to yield 25-hydroxyvitamin D (25(OH)D) or cal- cidiol. (vitamindwiki.com)
  • Cytochrome P450 24 subfamily A member 1 ( CYP24A1 ) encodes a 24-hydroxylase for degrading the active form of vitamin D through multiple pathways [ 6 , 7 ]. (biomedcentral.com)
  • It has been reported that the loss of CYP24A1 function resulted in increased serum concentration of 1,25-dihydroxyvitamin D [ 7 ]. (biomedcentral.com)
  • Tight control of the vitamin D system requires inactivation of its active compound 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) through 24-hydroxylation by means of the enzyme 24-hydroxylase (CYP24A1) and degradation to calcitroic acid [ 1 ]. (biomedcentral.com)
  • Sequence analysis of CYP24A1, which encodes 25-hydroxyvitamin D 24-hydroxylase, the key enzyme of 1,25-dihydroxyvitamin D(3) degradation, revealed mutations in three affected children, two were compound heterozygous for their specific mutations and one presented only one mutation in a single allele. (biomedcentral.com)
  • Jones G, Prosser DE, Kaufmann M: 25-Hydroxyvitamin D-24-hydroxylase (CYP24A1): its important role in the degradation of vitamin D. Arch Biochem Biophys. (biomedcentral.com)
  • CYP24A1 gene mutations induce infantile hypercalcemia, with high 1,25(OH)2D contrasting with low PTH levels. (calcoli-renali.it)
  • A 24-phenylsulfone analog of vitamin D inhibits 1alpha,25-dihydroxyvitamin D(3) degradation in vitamin D metabolism-competent cells. (nih.gov)
  • 1alpha,25-dihydroxyvitamin D3 induces vascular smooth muscle cell migration via activation of phosphatidylinositol 3-kinase. (uchicago.edu)
  • 2001). „1Alpha,25-dihydroxyvitamin D3 protects human keratinocytes from apoptosis by the formation of sphingosine-1-phosphate" . (wikipedia.org)
  • Our current observations correlate with these two patients' responsiveness to calciferols in vivo and suggest that their target organ defects can be partially or completely overcome with extremely high concentrations of 1,25(OH) 2 D. The two patients whose cells showed no detectable 24-OHase induction in vitro failed to show a calcemic response to high doses of calciferols in vivo. (tau.ac.il)
  • Another meta-analysis of nested case-control studies found a step-wise inverse association beyond a threshold of 27 ng/mL, but with flattening of effects above 35 ng/mL, in postmenopausal women but not in premenopausal.5 Unexpectedly, the meta-analysis conducted by Ordonez-Mena et al12 showed increased breast cancer risk with higher 25(OH)D concentrations. (vitamindwiki.com)
  • Treatment with 25(OH)D can normalize 1,25(OH) 2 D concentrations in patients with vitamin D deficiency. (medscape.com)
  • Design Umbrella review of the evidence across systematic reviews and meta-analyses of observational studies of plasma 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D concentrations and randomised controlled trials of vitamin D supplementation. (bmj.com)
  • 20503} Because 1,25-dihydroxy Vitamin D2 circulates at picomolar concentrations and is highly lipophilic, it is difficult to quantify. (bertin-bioreagent.com)
  • Plasma 1,25-dihydroxyvitamin D (1,25(OH) 2 D) is tightly controlled by plasma parathyroid hormone (PTH), serum calcium, serum phosphate, and fibroblast-like growth factor 23 (FGF-23). (medscape.com)
  • In this follow up case control study, BMD as well as serum levels of FGF23, calcium, phosphorus, alkaline phosphatase, creatinine, parathyroid hormone, 25 hydroxy vitamin D 3 and 1, 25 dihydroxy vitamin D 3 were measured in 47 children with IBD during flare and reassessed in the next remission. (biomedcentral.com)
  • These deficits lead to compensatory hypersecretion of parathyroid hormone, which results in bone loss [2,3]. (who.int)
  • The main effects of parathyroid hormone are to increase the concentration of plasma calcium by increasing the release of calcium and phosphate from bone matrix, increasing calcium reabsorption by the kidney, and increasing renal production of 1,25-dihydroxyvitamin D-3 (calcitriol), which increases intestinal absorption of calcium. (medscape.com)
  • The serum level of parathyroid hormone, calcium, phosphorus, and 25-hydroxyvitamin D should be measured. (medscape.com)
  • The enzyme also breaks down 25-hydroxyvitamin D (also known as calcidiol), which is the form of vitamin D that is stored in the body. (medlineplus.gov)
  • [ 3 ] Impaired production of the enzyme 1α-hydroxylase in kidney failure was thought to be the main mechanism. (medscape.com)
  • In tumor-induced osteomalacia, tumor-secreted FGF-23 inhibits enzyme 1α-hydroxylase and subsequently results in decreased 1,25(OH) 2 D synthesis. (medscape.com)
  • In granulomatous disease such as lymphoproliferative disorders, sarcoidosis, tuberculosis, and inflammatory bowel disease, 1α-hydroxylase enzyme activity was found in macrophages as the extrarenal source of 1,25(OH) 2 D. When 1α-hydroxylase is activated, it converts 25(OH)D to 1,25(OH) 2 D, just as what occurs under physiologic conditions in the kidneys. (medscape.com)
  • Renal excretion of excess dietary phosphate intake ensures maintenance of phosphate homeostasis, maintaining serum phosphate at a level of approximately 3-4 mg/dL in the serum. (medscape.com)
  • 1, 25 dihydroxy vitamin D 3 , FGF23, serum calcium and urinary phosphorus were significant determinants of BMD in IBD patients. (biomedcentral.com)
  • Historically, vitamin D had been linked to skeletal disease including calcium, phosphorus, and bone metabolism, 1 2 osteoporosis, 3 fractures, 4 5 muscle strength, 6 and falls. (bmj.com)
  • In particular, we monitor 1,25-dihydroxyvitamin D. Isolated serum calcium measurements are not adequate to follow these people, who may have a long period where their calcium is actually normalized. (medscape.com)
  • You really need to follow and monitor total 1,25- hydroxyvitamin D and 24-hour urinary calcium. (medscape.com)
  • In premenopausal and postmenopausal women, serum levels of 25-OHD, phosphorus and calcium were stable across the age span. (who.int)
  • Chez les femmes préménopausées et postménopausées, la concentration sérique en 25-OHD, en phosphore et en calcium était stable dans la fourchette d'âge. (who.int)
  • It is believed that compromises in vitamin D status and/or a reduced capability of the kidney to synthesize 1,25-dihydroxyvitamin D [1,25-(OH)2D] are responsible for impairment in dietary calcium absorption. (who.int)
  • Interaction between calcium and cadmium in the 1,25-dihydroxyvitamin D3 stimulated rat duodenum. (cdc.gov)
  • A 24-hour urine calcium measurement is necessary to rule out familial benign (hypocalciuric) hypercalcemia (FHH). (medscape.com)
  • Deficiency in either nutrient is associated with various disorders, including skeletal deformities, cardiovascular diseases, and metabolic syndrome [25-30]. (milkgenomics.org)
  • The biologically active form of vitamin D is 1,25-dihydroxyvitamin D (1,25(OH) 2 D). Measuring serum levels of 1,25(OH) 2 D should be considered upon suspicion of deficiency or excess of 1,25(OH) 2 D. (medscape.com)
  • Decreased levels of 1,25(OH) 2 D can result from chronic kidney disease , various heritable disorders, tumor-induced osteomalacia, the use of HIV protease inhibitors, or severe vitamin D deficiency . (medscape.com)
  • Severe vitamin D deficiency: 25(OH)D is the main substrate of 1,25(OH) 2 D. Vitamin D deficiency can affect the production of 1,25(OH) 2 D owing to the lack of substrate. (medscape.com)
  • It catalyzes hydroxylation reactions which lead to the degradation of 1,25-dihydroxyvitamin D3, the physiologically active form of vitamin D. Hydroxylation of the side chain produces calcitroic acid and other metabolites which are excreted in bile. (wikipedia.org)
  • 20502} By binding to the vitamin D receptor (VDR), 1,25-dihydroxy Vitamin D2 activate. (bertin-bioreagent.com)
  • 20502} By binding to the vitamin D receptor (VDR), 1,25-dihydroxy Vitamin D2 activates VDR to interact with the retinoid X receptor (RXR), forming the VDR/RXR/cofactor complex, which regulates gene transcription. (bertin-bioreagent.com)
  • It is now considered responsible for the entire five-step, 24-oxidation pathway from 1,25-(OH)2D3 producing calcitroic acid. (wikipedia.org)
  • In conclusion: (a) The measurement of 24-OHase induction by 1,25(OH) 2 D 3 in cultured skin fibroblasts is a sensitive in vitro test for defective genes in the 1,25(OH) 2 D effector pathway. (tau.ac.il)
  • Activation of the phosphatidylinositol 3-kinase/protein kinase Akt pathway mediates nitric oxide-induced endothelial cell migration and angiogenesis. (uchicago.edu)
  • Our objective was to investigate associations between variants in genes of vitamin D pathway with serum levels of 25-hydroxyvitamin D (25(OH)D), atopy, asthma and asthma severity in teenagers from Northeast Brazil. (biomedcentral.com)
  • Hypercalcemia or hypercalciuria may occur (noncaseating granulomas [NCGs] secrete 1,25 vitamin D). Hypercalcemia is seen in about 10-13% of patients, whereas hypercalciuria is 3 times more common. (medscape.com)
  • abstract = "1,25(OH)2D3 induces 25(OH)D3-24-hydroxylase (24-OHase) in cultured skin fibroblasts from normal subjects. (tau.ac.il)
  • Rarely, if the cause of hyperphosphatemia is not clear, 24-hour measurement of urinary phosphate can be performed. (medscape.com)
  • On a constaté une faible concentration sérique en 25-hydroxyvitamine D (25-OHD) chez 52,9 % des femmes. (who.int)
  • 3 ] Subsequent studies showed that diagnostic tests (PSA, prostate digital rectal exam, and prostate biopsy) had improved performance for detection of cancer and of high-grade cancer in men who received finasteride. (cigna.com)
  • The serum level of 25-hydroxyvitamin D (25-OHD) has been accepted as an index for vitamin D status [4]. (who.int)
  • This review highlights the genes and genetic polymorphisms currently studied, identified as influential in the genesis of IS, such as MMP-3, IL-6, type I collagen, and vitamin D and estrogen receptors. (scielo.br)
  • A presente revisão destaca os genes e polimorfismos genéticos atualmente estudados, indicados como tendo influência na gênese da EI, como os genes MMP-3, IL-6, do colágeno tipo 1, de receptores de vitamina D e de estrógenos. (scielo.br)
  • En ese sentido, existe un creciente enfoque en la identificación de genes, polimorfismos genéticos asociados y loci de susceptibilidad múltiples. (scielo.br)
  • La presente revisión destaca los genes y polimorfismos genéticos actualmente estudiados, identificados como influyentes en la génesis de la EI, como los genes MMP-3, IL-6, colágeno tipo 1 y receptores de vitamina D y de estrógeno. (scielo.br)
  • There was no significant correlation between creatinine clearance or serum PTH (r = -0.016, P = 0.66) and 25-OHD (r = 0.012, P = 0.74). (who.int)
  • In THP1 monocytic leukemia cells 1,25(OH)_{2} D_{3} stimulated TrxR mRNA levels 2-4‐fold by 4-8 h and enhanced TrxR activity (60%) (as measured by the dithionitrobenzole‐assay) after 24 h, which declined below baseline after 96 h. (iospress.com)
  • HIV protease inhibitors have been reported to markedly suppress the activities of 25- and 1α-hydroxylase and thus affect 1,25(OH) 2 D synthesis. (medscape.com)
  • However, phosphate retention and FGF-23 also contribute to the decreased synthesis of 1,25(OH) 2 D. (medscape.com)
  • We evaluated 24-OHase induction by 1,25(OH) 2 D 3 in skin fibroblasts from 10 normal subjects and from four unrelated patients with hereditary resistance to 1,25(OH) 2 D or vitamin D-dependent rickets type II (DD II). (tau.ac.il)
  • Apparent maximal [ 3 H]24,25(OH) 2 D 3 production in normal cell lines was 9 pmol/10 6 cells per 30 min and occurred after induction with 10 -8 M 1,25(OH) 2 D 3 . (tau.ac.il)
  • 24-OHase induction was detectable in normal fibroblasts at ~3 x 10 -10 M 1,25(OH) 2 D 3 . (tau.ac.il)
  • The two patients whose cells had a detectable 24-OHase induction by 1,25(OH) 2 D 3 showed a calcemic response to high doses of calciferols in vivo. (tau.ac.il)
  • Magnesium is involved in protein and nucleic acid synthesis, bone growth, energy metabolism, regulation of blood pressure, and in the activation of hundreds of enzymes [3,4]. (milkgenomics.org)
  • 3 Because this bone cell culture model demonstrates a capacity to respond to mechanical changes, we hypothesize that this model may also show differences in expression of metalloproteinases in response to cyclic mechanical stretch that can be used to model changes at the bone-implant interface. (allenpress.com)
  • Four clinical subgroups are defined by age: infantile (up to 3 years of age), juvenile (from 4 to 10 years of age), adolescent (from 10 to 18 years of age), and adult (after 18 years of age). (scielo.br)
  • Increased 1,25(OH) 2 D levels can result from extrarenal 1α-hydroxylation or hereditary vitamin D-resistant rickets. (medscape.com)
  • In the other, [ 3 H]24,25(OH) 2 D 3 production achieved normal levels, 7.3 pmol/10 6 cells per 30 min after 10 -6 M 1,25(OH) 2 D 3 . (tau.ac.il)
  • Elevated 1, 25-dihydroxyvitamin D levels are associated with protracted treatment in sarcoidosis. (medscape.com)
  • In one study, serum 1, 25-dihydroxyvitamin D levels were associated with patients requiring repeated regimens of systemic immunosuppressive therapy or longer than 1 year of therapy. (medscape.com)
  • Vitamin D and magnesium interact to maintain the physiologic functions of various organs, and abnormal levels of either nutrient can lead to serious organ dysfunctions [19-24]. (milkgenomics.org)
  • Chronic kidney disease: Low 1,25(OH) 2 D levels have been shown to present even in early stages of kidney failure. (medscape.com)
  • In a study by Levin et al (2007), 13% of patients with an estimated glomerular filtration rate (eGFR) greater than 80 mL/min and more than 60% of patients with an eGFR of less than 30 mL/min had low serum levels of 1,25(OH) 2 D. (medscape.com)
  • A positive correlation between serum levels of 25(OH)D and 1,25(OH) 2 D was observed during seasonal changes. (medscape.com)
  • The expression and activity of mRNA for several MMPs (2, 3, 9, and 10) was assessed. (allenpress.com)
  • Main outcome measure: Temporal changes in the serum 24,25(OH) 2 D 3 /25(OH)D 3 ratio. (elsevierpure.com)
  • The 24,25(OH) 2 D 3 /25(OH)D 3 ratio remained in the normal range with both dosing regimens. (elsevierpure.com)
  • The meta-analysis conducted by Chen et al11 revealed that women with the highest quantile of circulating 25(OH)D was associated with a 45% (odds ratio OR = 0.55, 95% confidence interval CI = 0.38-0.80) decrease in breast cancer risk when compared with those women with the lowest quantile of blood 25(OH)D. (vitamindwiki.com)
  • Diagnosis is based on a reduced 24,25-dihydroxyvitamin D to 25-hydroxyvitamin D ratio and confirmed by genetic analyses. (calcoli-renali.it)
  • 1,25-dihydroxy Vitamin D2 is the active circulating metabolite of vitamin D2 formed by 25-hydroxylase in the liver and 25-hydroxyvitamin D-hydroxylase in the kidney. (bertin-bioreagent.com)
  • Reference ranges of 1,25(OH) 2 D vary since different laboratories may use different methods for measuring 1,25(OH) 2 D and different units of measurement. (medscape.com)
  • Vitamin D is the general term for a group of secosteroid metabolites whose active form is 1α-25-dihydroxyvitamin D (1,25(OH)D) [ 15 ]. (biomedcentral.com)
  • GCMS analysis of AE identified 3-beta-hydroxy-5-cholen-24-oic-acid as active compound, while in ME Beta. (springeropen.com)
  • 2014. Regulation of the human cathelicidin antimicrobial peptide gene by 1α,25-dihydroxyvitamin D3 in primary immune cells. . (oregonstate.edu)
  • lipid extracts of the cells were analyzed for [ 3 H]24,25(OH) 2 D 3 by high performance liquid chromatography and periodate oxidation. (tau.ac.il)
  • In one, [ 3 H]24,25(OH) 2 D 3 production reached 2.9 pmol/10 6 cells per 30 min at 10 -6 M 1,25(OH) 2 D 3 (30% normal maximum at 10 -6 M 1,25(OH) 2 D 3 ). (tau.ac.il)
  • This disease is characterized by a chronic inflammation of lower airways that include complex pathophysiological mechanisms involving several pro-inflammatory cells and molecules, including different cytokine profiles that can change according to environmental and genetic factors [ 3 , 4 ]. (biomedcentral.com)
  • The decrease of 1,25(OH) 2 D level is more prominent when kidney failure progresses. (medscape.com)
  • Vitamin D metabolites were measured in serum and breast milk at baseline, 1, 3, 7, 14 and 28 days. (elsevierpure.com)
  • All patients were diagnosed with NC after ultrasonographic assessment at a mean age of 3,5 years and were analyzed with the diagnostic flowchart proposed by Ammenti [ 3 ] for detecting causes of NC. (biomedcentral.com)
  • It is the most common form of spinal deformity with a prevalence of approximately 2-3%, 10% of which will progress over time. (scielo.br)
  • The finasteride trial enrolled men with a prostate-specific antigen (PSA) of less than 3 ng/mL, constituting the majority of U.S. men, but those with a lower risk of cancer. (cigna.com)
  • b) 4-Hydroxytamoxifen (but not tamoxifen), genistein (but not genistin), daidzein, and probably other nutritional and chemopreventive anti-cancer agents could up-regulate expression of p27 via receptor protein tyrosine kinases (RPTKs), phosphoinositide 3-kinase (PI3K), phosphoinosite-dependent kinase (PDK), Akt/PKB and mTOR. (biomedcentral.com)
  • In addition to that, all the other asthma phenotypes that do not include sIgE production (specific Immunoglobulin E) are classified as non-atopic [ 3 ]. (biomedcentral.com)
  • The more extensive surgeries, such as biliary-pancreatic diversion surgery or more extended Roux-en-Y gastric bypass surgery, may result in more protein malabsorption . (medscape.com)
  • We identified the selenoprotein thioredoxin reductase (TrxR) as a new molecular target for 1,25(OH)_{2} D_{3} in monocytes during this process. (iospress.com)
  • 3 , 4 Poor growth and nutrition have also been reported in refugee children arriving in the United States, although studies suggest that most refugee children experience catch-up growth and reach normal weight within 6-24 months of arrival in the United States. (cdc.gov)
  • 3 H]24,25(OH) 2 D 3 formation after exposure to 1,25(OH) 2 D 3 was abnormal in fibroblasts from all four patients with DD II. (tau.ac.il)
  • The goals of nutrition therapy during the wait for transplantation are (1) to replenish malnourished individuals, (2) to maintain the status of those with adequate muscle and energy reserve, (3) to promote weight loss in candidates with excessive weight based on body mass index (BMI), and (4) to manage patients' symptoms to maximize quality of life. (medscape.com)
  • Patients underwent clinical and laboratory reassessment 3 months after achieving remission depending on feasibility of follow up visits and availability of required tests as DXA scan. (biomedcentral.com)