Cells with high proliferative and self renewal capacities derived from adults.
Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.
The transfer of STEM CELLS from one individual to another within the same species (TRANSPLANTATION, HOMOLOGOUS) or between species (XENOTRANSPLANTATION), or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). The source and location of the stem cells determines their potency or pluripotency to differentiate into various cell types.
Cells derived from the BLASTOCYST INNER CELL MASS which forms before implantation in the uterine wall. They retain the ability to divide, proliferate and provide progenitor cells that can differentiate into specialized cells.
Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.
Specialized stem cells that are committed to give rise to cells that have a particular function; examples are MYOBLASTS; MYELOID PROGENITOR CELLS; and skin stem cells. (Stem Cells: A Primer [Internet]. Bethesda (MD): National Institutes of Health (US); 2000 May [cited 2002 Apr 5]. Available from: http://www.nih.gov/news/stemcell/primer.htm)
Progenitor cells from which all blood cells derive.
Cells that can give rise to cells of the three different GERM LAYERS.
A particular zone of tissue composed of a specialized microenvironment where stem cells are retained in a undifferentiated, self-renewable state.
Bone-marrow-derived, non-hematopoietic cells that support HEMATOPOETIC STEM CELLS. They have also been isolated from other organs and tissues such as UMBILICAL CORD BLOOD, umbilical vein subendothelium, and WHARTON JELLY. These cells are considered to be a source of multipotent stem cells because they include subpopulations of mesenchymal stem cells.
Nonparasitic free-living flatworms of the class Turbellaria. The most common genera are Dugesia, formerly Planaria, which lives in water, and Bipalium, which lives on land. Geoplana occurs in South America and California.
The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.
The physiological renewal, repair, or replacement of tissue.
Transfer of MESENCHYMAL STEM CELLS between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS).
Transfer of HEMATOPOIETIC STEM CELLS from BONE MARROW or BLOOD between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). Hematopoietic stem cell transplantation has been used as an alternative to BONE MARROW TRANSPLANTATION in the treatment of a variety of neoplasms.
A field of medicine concerned with developing and using strategies aimed at repair or replacement of damaged, diseased, or metabolically deficient organs, tissues, and cells via TISSUE ENGINEERING; CELL TRANSPLANTATION; and ARTIFICIAL ORGANS and BIOARTIFICIAL ORGANS and tissues.
Experimentation on STEM CELLS and on the use of stem cells.
Cells from adult organisms that have been reprogrammed into a pluripotential state similar to that of EMBRYONIC STEM CELLS.
Self-renewing cells that generate the main phenotypes of the nervous system in both the embryo and adult. Neural stem cells are precursors to both NEURONS and NEUROGLIA.
All of the processes involved in increasing CELL NUMBER including CELL DIVISION.
Methods for maintaining or growing CELLS in vitro.
Therapies that involve the TRANSPLANTATION of CELLS or TISSUES developed for the purpose of restoring the function of diseased or dysfunctional cells or tissues.
Cells contained in the bone marrow including fat cells (see ADIPOCYTES); STROMAL CELLS; MEGAKARYOCYTES; and the immediate precursors of most blood cells.
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.
Cells derived from a FETUS that retain the ability to divide, proliferate and provide progenitor cells that can differentiate into specialized cells.
Cell separation is the process of isolating and distinguishing specific cell types or individual cells from a heterogeneous mixture, often through the use of physical or biological techniques.
Highly proliferative, self-renewing, and colony-forming stem cells which give rise to NEOPLASMS.
Changes in the organism associated with senescence, occurring at an accelerated rate.
A hematopoietic growth factor and the ligand of the cell surface c-kit protein (PROTO-ONCOGENE PROTEINS C-KIT). It is expressed during embryogenesis and is a growth factor for a number of cell types including the MAST CELLS and the MELANOCYTES in addition to the HEMATOPOIETIC STEM CELLS.
Generating tissue in vitro for clinical applications, such as replacing wounded tissues or impaired organs. The use of TISSUE SCAFFOLDING enables the generation of complex multi-layered tissues and tissue structures.
A tube-like invagination of the EPIDERMIS from which the hair shaft develops and into which SEBACEOUS GLANDS open. The hair follicle is lined by a cellular inner and outer root sheath of epidermal origin and is invested with a fibrous sheath derived from the dermis. (Stedman, 26th ed) Follicles of very long hairs extend into the subcutaneous layer of tissue under the SKIN.
An octamer transcription factor that is expressed primarily in totipotent embryonic STEM CELLS and GERM CELLS and is down-regulated during CELL DIFFERENTIATION.
Euploid male germ cells of an early stage of SPERMATOGENESIS, derived from prespermatogonia. With the onset of puberty, spermatogonia at the basement membrane of the seminiferous tubule proliferate by mitotic then meiotic divisions and give rise to the haploid SPERMATOCYTES.
The decrease in the cell's ability to proliferate with the passing of time. Each cell is programmed for a certain number of cell divisions and at the end of that time proliferation halts. The cell enters a quiescent state after which it experiences CELL DEATH via the process of APOPTOSIS.
A richly vascularized and innervated connective tissue of mesodermal origin, contained in the central cavity of a tooth and delimited by the dentin, and having formative, nutritive, sensory, and protective functions. (Jablonski, Dictionary of Dentistry, 1992)
The reproductive cells in multicellular organisms at various stages during GAMETOGENESIS.
The formation of cartilage. This process is directed by CHONDROCYTES which continually divide and lay down matrix during development. It is sometimes a precursor to OSTEOGENESIS.
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.
Transference of cells within an individual, between individuals of the same species, or between individuals of different species.
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
Parts of plants that usually grow vertically upwards towards the light and support the leaves, buds, and reproductive structures. (From Concise Dictionary of Biology, 1990)
A reverse developmental process in which terminally differentiated cells with specialized functions revert back to a less differentiated stage within their own CELL LINEAGE.
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.
The entity of a developing mammal (MAMMALS), generally from the cleavage of a ZYGOTE to the end of embryonic differentiation of basic structures. For the human embryo, this represents the first two months of intrauterine development preceding the stages of the FETUS.
Elongated, spindle-shaped, quiescent myoblasts lying in close contact with adult skeletal muscle. They are thought to play a role in muscle repair and regeneration.
A subclass of SOX transcription factors that are expressed in neuronal tissue where they may play a role in the regulation of CELL DIFFERENTIATION. Members of this subclass are generally considered to be transcriptional activators.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The differentiation of pre-adipocytes into mature ADIPOCYTES.
Transplantation of an individual's own tissue from one site to another site.
Connective tissue cells of an organ found in the loose connective tissue. These are most often associated with the uterine mucosa and the ovary as well as the hematopoietic system and elsewhere.
A type VI intermediate filament protein expressed mostly in nerve cells where it is associated with the survival, renewal and mitogen-stimulated proliferation of neural progenitor cells.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.
The release of stem cells from the bone marrow into the peripheral blood circulation for the purpose of leukapheresis, prior to stem cell transplantation. Hematopoietic growth factors or chemotherapeutic agents often are used to stimulate the mobilization.
Glycoproteins found on immature hematopoietic cells and endothelial cells. They are the only molecules to date whose expression within the blood system is restricted to a small number of progenitor cells in the bone marrow.
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.
Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.
A cytologic technique for measuring the functional capacity of stem cells by assaying their activity.
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 naturally occurring phenomenon where terminally differentiated cells dedifferentiate to the point where they can switch CELL LINEAGES. The cells then differentiate into other cell types.
A genus of the family RETROVIRIDAE consisting of non-oncogenic retroviruses that produce multi-organ diseases characterized by long incubation periods and persistent infection. Lentiviruses are unique in that they contain open reading frames (ORFs) between the pol and env genes and in the 3' env region. Five serogroups are recognized, reflecting the mammalian hosts with which they are associated. HIV-1 is the type species.
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.
Cell growth support structures composed of BIOCOMPATIBLE MATERIALS. They are specially designed solid support matrices for cell attachment in TISSUE ENGINEERING and GUIDED TISSUE REGENERATION uses.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.
The process of bone formation. Histogenesis of bone including ossification.
An HMG-box domain (HMG-BOX DOMAINS) found highly expressed in embryonic tissue and in placenta.
An abnormal congenital condition, associated with defects in the LAMIN TYPE A gene, which is characterized by premature aging in children, where all the changes of cell senescence occur. It is manifested by premature greying; hair loss; hearing loss (DEAFNESS); cataracts (CATARACT); ARTHRITIS; OSTEOPOROSIS; DIABETES MELLITUS; atrophy of subcutaneous fat; skeletal hypoplasia; elevated urinary HYALURONIC ACID; and accelerated ATHEROSCLEROSIS. Many affected individuals develop malignant tumors, especially SARCOMA.
Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.
A genetic process by which the adult organism is realized via mechanisms that lead to the restriction in the possible fates of cells, eventually leading to their differentiated state. Mechanisms involved cause heritable changes to cells without changes to DNA sequence such as DNA METHYLATION; HISTONE modification; DNA REPLICATION TIMING; NUCLEOSOME positioning; and heterochromatization which result in selective gene expression or repression.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Wnt proteins are a large family of secreted glycoproteins that play essential roles in EMBRYONIC AND FETAL DEVELOPMENT, and tissue maintenance. They bind to FRIZZLED RECEPTORS and act as PARACRINE PROTEIN FACTORS to initiate a variety of SIGNAL TRANSDUCTION PATHWAYS. The canonical Wnt signaling pathway stabilizes the transcriptional coactivator BETA CATENIN.
A technique of culturing mixed cell types in vitro to allow their synergistic or antagonistic interactions, such as on CELL DIFFERENTIATION or APOPTOSIS. Coculture can be of different types of cells, tissues, or organs from normal or disease states.
The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.
A multisubunit polycomb protein complex with affinity for CHROMATIN that contains methylated HISTONE H3. It contains an E3 ubiquitin ligase activity that is specific for HISTONE H2A and works in conjunction with POLYCOMB REPRESSIVE COMPLEX 2 to effect EPIGENETIC REPRESSION.
The process that reverts CELL NUCLEI of fully differentiated somatic cells to a pluripotent or totipotent state. This process can be achieved to a certain extent by NUCLEAR TRANSFER TECHNIQUES, such as fusing somatic cell nuclei with enucleated pluripotent embryonic stem cells or enucleated totipotent oocytes. GENE EXPRESSION PROFILING of the fused hybrid cells is used to determine the degree of reprogramming. Dramatic results of nuclear reprogramming include the generation of cloned mammals, such as Dolly the sheep in 1997.
A complex signaling pathway whose name is derived from the DROSOPHILA Wg gene, which when mutated results in the wingless phenotype, and the vertebrate INT gene, which is located near integration sites of MOUSE MAMMARY TUMOR VIRUS. The signaling pathway is initiated by the binding of WNT PROTEINS to cells surface WNT RECEPTORS which interact with the AXIN SIGNALING COMPLEX and an array of second messengers that influence the actions of BETA CATENIN.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
Established cell cultures that have the potential to propagate indefinitely.
The quality of surface form or outline of CELLS.
Dense fibrous layer formed from mesodermal tissue that surrounds the epithelial enamel organ. The cells eventually migrate to the external surface of the newly formed root dentin and give rise to the cementoblasts that deposit cementum on the developing root, fibroblasts of the developing periodontal ligament, and osteoblasts of the developing alveolar bone.
The development and formation of various types of BLOOD CELLS. Hematopoiesis can take place in the BONE MARROW (medullary) or outside the bone marrow (HEMATOPOIESIS, EXTRAMEDULLARY).
Mature osteoblasts that have become embedded in the BONE MATRIX. They occupy a small cavity, called lacuna, in the matrix and are connected to adjacent osteocytes via protoplasmic projections called canaliculi.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Formation of NEURONS which involves the differentiation and division of STEM CELLS in which one or both of the daughter cells become neurons.
Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).
A bone morphogenetic protein that is a potent inducer of BONE formation. It plays additional roles in regulating CELL DIFFERENTIATION of non-osteoblastic cell types and epithelial-mesenchymal interactions.
Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.
A family of conserved cell surface receptors that contain EPIDERMAL GROWTH FACTOR repeats in their extracellular domain and ANKYRIN repeats in their cytoplasmic domains. The cytoplasmic domain of notch receptors is released upon ligand binding and translocates to the CELL NUCLEUS where it acts as transcription factor.
The processes whereby the internal environment of an organism tends to remain balanced and stable.
The section of the alimentary canal from the STOMACH to the ANAL CANAL. It includes the LARGE INTESTINE and SMALL INTESTINE.
The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.
Precursor cells destined to differentiate into skeletal myocytes (MYOCYTES, SKELETAL).
The transference of BONE MARROW from one human or animal to another for a variety of purposes including HEMATOPOIETIC STEM CELL TRANSPLANTATION or MESENCHYMAL STEM CELL TRANSPLANTATION.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
Transplantation of stem cells collected from the peripheral blood. It is a less invasive alternative to direct marrow harvesting of hematopoietic stem cells. Enrichment of stem cells in peripheral blood can be achieved by inducing mobilization of stem cells from the BONE MARROW.
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
A group of genetically identical cells all descended from a single common ancestral cell by mitosis in eukaryotes or by binary fission in prokaryotes. Clone cells also include populations of recombinant DNA molecules all carrying the same inserted sequence. (From King & Stansfield, Dictionary of Genetics, 4th ed)
The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.
Single cells that have the potential to form an entire organism. They have the capacity to specialize into extraembryonic membranes and tissues, the embryo, and all postembryonic tissues and organs. (Stem Cells: A Primer [Internet]. Bethesda (MD): National Institutes of Health (US); 2000 May [cited 2002 Apr 5]. Available from: http://www.nih.gov/news/stemcell/primer.htm)
The number of CELLS of a specific kind, usually measured per unit volume or area of sample.
The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells.
Mammalian pigment cells that produce MELANINS, pigments found mainly in the EPIDERMIS, but also in the eyes and the hair, by a process called melanogenesis. Coloration can be altered by the number of melanocytes or the amount of pigment produced and stored in the organelles called MELANOSOMES. The large non-mammalian melanin-containing cells are called MELANOPHORES.
Elements of limited time intervals, contributing to particular results or situations.
Transplantation between individuals of the same species. Usually refers to genetically disparate individuals in contradistinction to isogeneic transplantation for genetically identical individuals.
The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.
Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.
A nucleoside that substitutes for thymidine in DNA and thus acts as an antimetabolite. It causes breaks in chromosomes and has been proposed as an antiviral and antineoplastic agent. It has been given orphan drug status for use in the treatment of primary brain tumors.
A subclass of developmentally regulated lamins having a neutral isoelectric point. They are found to disassociate from nuclear membranes during mitosis.
Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.
A multi-functional catenin that participates in CELL ADHESION and nuclear signaling. Beta catenin binds CADHERINS and helps link their cytoplasmic tails to the ACTIN in the CYTOSKELETON via ALPHA CATENIN. It also serves as a transcriptional co-activator and downstream component of WNT PROTEIN-mediated SIGNAL TRANSDUCTION PATHWAYS.
A species of fruit fly much used in genetics because of the large size of its chromosomes.
Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.
Profound physical changes during maturation of living organisms from the immature forms to the adult forms, such as from TADPOLES to frogs; caterpillars to BUTTERFLIES.
Restoration of integrity to traumatized tissue.
Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.
Fusion of somatic cells in vitro or in vivo, which results in somatic cell hybridization.
Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
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.
Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.
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.
Mice homozygous for the mutant autosomal recessive gene "scid" which is located on the centromeric end of chromosome 16. These mice lack mature, functional lymphocytes and are thus highly susceptible to lethal opportunistic infections if not chronically treated with antibiotics. The lack of B- and T-cell immunity resembles severe combined immunodeficiency (SCID) syndrome in human infants. SCID mice are useful as animal models since they are receptive to implantation of a human immune system producing SCID-human (SCID-hu) hematochimeric mice.
New abnormal growth of tissue. Malignant neoplasms show a greater degree of anaplasia and have the properties of invasion and metastasis, compared to benign neoplasms.
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.
Cells in the body that store FATS, usually in the form of TRIGLYCERIDES. WHITE ADIPOCYTES are the predominant type and found mostly in the abdominal cavity and subcutaneous tissue. BROWN ADIPOCYTES are thermogenic cells that can be found in newborns of some species and hibernating mammals.
The artificial induction of GENE SILENCING by the use of RNA INTERFERENCE to reduce the expression of a specific gene. It includes the use of DOUBLE-STRANDED RNA, such as SMALL INTERFERING RNA and RNA containing HAIRPIN LOOP SEQUENCE, and ANTI-SENSE OLIGONUCLEOTIDES.
Blood of the fetus. Exchange of nutrients and waste between the fetal and maternal blood occurs via the PLACENTA. The cord blood is blood contained in the umbilical vessels (UMBILICAL CORD) at the time of delivery.
The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.
Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.
A family of intercellular signaling proteins that play and important role in regulating the development of many TISSUES and organs. Their name derives from the observation of a hedgehog-like appearance in DROSOPHILA embryos with genetic mutations that block their action.
The largest family of cell surface receptors involved in SIGNAL TRANSDUCTION. They share a common structure and signal through HETEROTRIMERIC G-PROTEINS.
A protein-tyrosine kinase receptor that is specific for STEM CELL FACTOR. This interaction is crucial for the development of hematopoietic, gonadal, and pigment stem cells. Genetic mutations that disrupt the expression of PROTO-ONCOGENE PROTEINS C-KIT are associated with PIEBALDISM, while overexpression or constitutive activation of the c-kit protein-tyrosine kinase is associated with tumorigenesis.
The two longitudinal ridges along the PRIMITIVE STREAK appearing near the end of GASTRULATION during development of nervous system (NEURULATION). The ridges are formed by folding of NEURAL PLATE. Between the ridges is a neural groove which deepens as the fold become elevated. When the folds meet at midline, the groove becomes a closed tube, the NEURAL TUBE.
Transplantation of STEM CELLS collected from the fetal blood remaining in the UMBILICAL CORD and the PLACENTA after delivery. Included are the HEMATOPOIETIC STEM CELLS.
Techniques and strategies which include the use of coding sequences and other conventional or radical means to transform or modify cells for the purpose of treating or reversing disease conditions.
A family of related, adhesive glycoproteins which are synthesized, secreted, and incorporated into the extracellular matrix of a variety of cells, including alpha granules of platelets following thrombin activation and endothelial cells. They interact with a number of BLOOD COAGULATION FACTORS and anticoagulant factors. Five distinct forms have been identified, thrombospondin 1, -2, -3, -4, and cartilage oligomeric matrix protein (COMP). They are involved in cell adhesion, platelet aggregation, cell proliferation, angiogenesis, tumor metastasis, VASCULAR SMOOTH MUSCLE growth, and tissue repair.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere.
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.
Regulatory proteins and peptides that are signaling molecules involved in the process of PARACRINE COMMUNICATION. They are generally considered factors that are expressed by one cell and are responded to by receptors on another nearby cell. They are distinguished from HORMONES in that their actions are local rather than distal.
ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.
Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
Experimentation on, or using the organs or tissues from, a human or other mammalian conceptus during the prenatal stage of development that is characterized by rapid morphological changes and the differentiation of basic structures. In humans, this includes the period from the time of fertilization to the end of the eighth week after fertilization.
Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.
Addition of methyl groups to DNA. DNA methyltransferases (DNA methylases) perform this reaction using S-ADENOSYLMETHIONINE as the methyl group donor.
Filaments 7-11 nm in diameter found in the cytoplasm of all cells. Many specific proteins belong to this group, e.g., desmin, vimentin, prekeratin, decamin, skeletin, neurofilin, neurofilament protein, and glial fibrillary acid protein.
Polymorphic cells that form cartilage.
A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
The main structural component of the LIVER. They are specialized EPITHELIAL CELLS that are organized into interconnected plates called lobules.
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.
Preparative treatment of transplant recipient with various conditioning regimens including radiation, immune sera, chemotherapy, and/or immunosuppressive agents, prior to transplantation. Transplantation conditioning is very common before bone marrow transplantation.
A true neoplasm composed of a number of different types of tissue, none of which is native to the area in which it occurs. It is composed of tissues that are derived from three germinal layers, the endoderm, mesoderm, and ectoderm. They are classified histologically as mature (benign) or immature (malignant). (From DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1642)
Spontaneous aggregations of human embryonic stem cells that occur in vitro after culturing in a medium that lacks LEUKEMIC INHIBITORY FACTOR. The embryoid bodies can further differentiate into cells that represent different lineages.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
Adherence of cells to surfaces or to other cells.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
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.
Spherical, heterogeneous aggregates of proliferating, quiescent, and necrotic cells in culture that retain three-dimensional architecture and tissue-specific functions. The ability to form spheroids is a characteristic trait of CULTURED TUMOR CELLS derived from solid TUMORS. Cells from normal tissues can also form spheroids. They represent an in-vitro model for studies of the biology of both normal and malignant cells. (From Bjerkvig, Spheroid Culture in Cancer Research, 1992, p4)
The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
The clinical entity characterized by anorexia, diarrhea, loss of hair, leukopenia, thrombocytopenia, growth retardation, and eventual death brought about by the GRAFT VS HOST REACTION.
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.
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.
A strain of non-obese diabetic mice developed in Japan that has been widely studied as a model for T-cell-dependent autoimmune insulin-dependent diabetes mellitus in which insulitis is a major histopathologic feature, and in which genetic susceptibility is strongly MHC-linked.
Non-invasive imaging of cells that have been labeled non-destructively, such as with nanoemulsions or reporter genes that can be detected by molecular imaging, to monitor their location, viability, cell lineage expansion, response to drugs, movement, or other behaviors in vivo.
A glycoprotein of MW 25 kDa containing internal disulfide bonds. It induces the survival, proliferation, and differentiation of neutrophilic granulocyte precursor cells and functionally activates mature blood neutrophils. Among the family of colony-stimulating factors, G-CSF is the most potent inducer of terminal differentiation to granulocytes and macrophages of leukemic myeloid cell lines.
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).
A cell adhesion protein that was originally identified as a heat stable antigen in mice. It is involved in METASTASIS and is highly expressed in many NEOPLASMS.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
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.
Transplantation between animals of different species.
An annular transitional zone, approximately 1 mm wide, between the cornea and the bulbar conjunctiva and sclera. It is highly vascular and is involved in the metabolism of the cornea. It is ophthalmologically significant in that it appears on the outer surface of the eyeball as a slight furrow, marking the line between the clear cornea and the sclera. (Dictionary of Visual Science, 3d ed)
The malignant stem cells of TERATOCARCINOMAS, which resemble pluripotent stem cells of the BLASTOCYST INNER CELL MASS. The EC cells can be grown in vitro, and experimentally induced to differentiate. They are used as a model system for studying early embryonic cell differentiation.
Bone-forming cells which secrete an EXTRACELLULAR MATRIX. HYDROXYAPATITE crystals are then deposited into the matrix to form bone.
Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.
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.

Adult neural stem/progenitor cells in neurodegenerative repair. (1/1106)

Although the mammalian brain has long been thought to be entirely postmitotic, the recent discovery has confirmed an existence of neural stem or progenitor cells in various regions of the adult mammalian brain. Like embryonic stem cells, adult neural progenitor cells possess the capacity of self-renewal and differentiation potential for neurogenesis or gliogenesis. In addition to the subventricular zone and hippocampus where active cell division naturally occurs, adult neural progenitors with neurogenic potential exist in the striatum and the vicinity of dopaminergic neurons in the substantia nigra. Normally, progenitors in those regions proliferate at a low level, and most proliferated cells remain uncommitted. In response to the selective lesion of nigrostriatal dopaminergic pathway by the neurotoxins, such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6-hydroxydopamine, progenitors in the injured areas markedly increase their proliferation rate. Depending upon the magnitude and kinetics of the lesion, neurogenesis and gliogenesis were induced in the lesion sites at varying extents. A large number of growth and neurotrophic factors influence proliferation and/or differentiation of progenitor cells under normal and lesioned conditions. Some factors (epidermal and basic fibroblast growth factors and brain-derived neurotrophic factor) are facilitatory, while others (usually bone morphogenetic proteins) are inhibitory, for controlling division and fate of neuronal or glial progenitors. Expression of endogenous factors and their respective receptors in existing and newborn cells are also subject to be altered by the lesion. These genomic responses are considered to be important elements for the formation of a local molecular niche for a given phenotypic cell regeneration. Taken together, adult neural progenitor cells in the nigrostriatal dopaminergic system have the ability to respond to the lesion to repopulate missing cells. The regenerative neuro- or gliogenesis in situ can, at least in part, endogenously compensate injured neural elements, and achieve a self-repair of neurodegenerative disorders such as Parkinson's disease.  (+info)

Differentiation versus plasticity: fixing the fate of undetermined adult stem cells. (2/1106)

Adult mesenchymal stem cells own a considerable plasticity, which enables them to respond to various extra- and intracellular cues and exert, at least partially, various differentiation pathways. Recently, we have shown that multipotent adult stem cells (MASCs) derived from the mouse bone marrow (mBM-MASCs) consist of distinct cell populations that have similar differentiation abilities but differ in the expression of several stem cell markers. Despite their remarkable developmental potential MASCs seem to miss crucial components to complete specific differentiation programs necessary to acquire a fully functional phenotype. A thorough analysis of active and inactive regulatory circuits in multipotent adult stem cells might lead the way to a controlled programming of these cells and rational therapeutic applications.  (+info)

The consensus of the task force of the European Society of Cardiology concerning the clinical investigation of the use of autologous adult stem cells for repair of the heart. (3/1106)

A task force has been established by the European Society of Cardiology to investigate the role of progenitor/stem cell therapy in the treatment of cardiovascular disease. This article is the consensus of this group, of what clinical studies are needed in this field, and the challenges to be addressed in the translation of progenitor/stem cell biology to repair of the heart.  (+info)

X inactivation patterns of closely, but not distantly, related cells are highly correlated: little evidence for stem cell plasticity in normal females. (4/1106)

The early, random nature of X inactivation should cause related cells to have similar, but distinctive, active X chromosomes. We assessed the frequency of stem cell plasticity using X inactivation proportions (XIPs), determined at the human androgen receptor locus, in paired tissue samples from healthy individuals. Tissues sampled were stomach (n = 18 informative females), duodenum (n = 18), colon (n = 10) with corresponding peripheral blood samples (n = 33), and varicose veins (n = 28) with corresponding T cells (n = 26) and peripheral blood granulocytes (n = 25). XIPs from samples thought to have common stem cell origins were highly correlated: multiple samples from single vein, r = .80 (n = 24); T cells versus granulocytes, r = .67 (n = 23); duodenum versus stomach, r = .63 (n = 12). Blood cells and vessels are derived from a common hemangioblast, but XIP correlations were moderate or poor: vein versus T cells, r = .42 (n = 26); vein versus granulocytes, r = .11 (n = 25). X inactivation is believed to be a late process in gut, especially hind-gut, with corresponding independence from blood precursors. Correlations with blood cells were low: stomach, r = .23 (18); duodenum, r = .21 (18); colon, r = .034 (10). Any crossover of stem cells between different organs during adult life should increase correlations with age; no such increase was seen. This study confirms that XIPs can be used to track stem cell populations, provides a theoretical basis for the power of such studies, and indicates that hemopoietic stem cell plasticity is, at most, uncommon in normal humans.  (+info)

A role for angiotensin-converting enzyme in the characterization, enrichment, and proliferation potential of adult murine pituitary colony-forming cells. (5/1106)

Recently, we described a rare cell type within the adult murine pituitary gland with progenitor cell hallmarks (PCFCs). PCFCs are contained exclusively within a subpopulation of cells that import fluorescent beta-Ala-Lys-Nepsilon-AMCA (7-amino-4-methylcoumarin-3-acetic acid). Herein, we investigate the utility of cell surface molecules angiotensin-converting enzyme (ACE) and stem cell antigen-1 (Sca-1) to further enrich for PCFCs. ACE and Sca-1 were expressed on 61% and 55% of AMCA(+)CD45(-)CD31(-) cells, respectively, and coexpressed on 38%. ACE(+)Sca-1(+)AMCA(+) cells enriched for PCFCs by 195-fold over unselected cells. ACE(+)AMCA(+) cells enriched for PCFCs by 170-fold, and colonies were twofold larger than for AMCA(+) selection alone. Conversely, ACE(-)-selected cells reduced both colony-forming activity and size. Notably, colonies generated from AMCA(+) cells obtained from ACE(null) mice were 2.7-fold smaller than for wild-type mice. These data identify ACE as a previously unrecognized marker of PCFCs and suggest that ACE is functionally important for PCFC proliferation. Anatomically, the cells that imported AMCA and expressed ACE were situated in the marginal epithelial cell layer of the pituitary cleft and in the adjacent subluminal zone, thus supporting previous proposals that the luminal zone is a source of precursor cells in the adult pituitary.  (+info)

Regrow or repair: potential regenerative therapies for the kidney. (6/1106)

Regenerative medicine is being heralded in a similar way as gene therapy was some 15 yr ago. It is an area of intense excitement and potential, as well as myth and disinformation. However, with the increasing rate of end-stage renal failure and limited alternatives for its treatment, we must begin to investigate seriously potential regenerative approaches for the kidney. This review defines which regenerative options there might be for renal disease, summarizes the progress that has been made to date, and investigates some of the unique obstacles to such treatments that the kidney presents. The options discussed include in situ organ repair via bone marrow recruitment or dedifferentiation; ex vivo stem cell therapies, including both autologous and nonautologous options; and bioengineering approaches for the creation of a replacement organ.  (+info)

Cell cycle quiescence of early lymphoid progenitors in adult bone marrow. (7/1106)

Lymphocyte production in bone marrow (BM) requires substantial cell division, but the relationship between largely quiescent stem cells and dividing lymphoid progenitors is poorly understood. Therefore, the proliferation and cell cycle status of murine hematopoietic progenitors that have just initiated the lymphoid differentiation program represented the focus of this study. Continuous bromo-2'-deoxyuridine (BrdU) incorporation and DNA/RNA analysis by flow cytometry revealed that a surprisingly large fraction of RAG-1(+)c-kit(hi) early lymphoid progenitors (ELPs) and RAG-1(+)c-kit(lo) pro-lymphocytes (Pro-Ls) in adult BM were in cell cycle quiescence. In contrast, their counterparts in 14-day fetal liver actively proliferated. Indeed, the growth fraction (cells in G(1)-S-G(2)-M phases) of fetal ELPs was on average 80% versus only 30% for adult ELPs. After 5-fluorouracil treatment, as many as 60% of the adult ELP-enriched population was in G(1)-S-G(2)-M and 34% incorporated BrdU in 6 hours. Transcripts for Bcl-2, p21Cip1/Waf1, and p27 Kip1 cell cycle regulatory genes correlated inversely well with proliferative activity. Interestingly, adult lymphoid progenitors in rebound had the high potential for B lymphopoiesis in culture typical of their fetal counterparts. Thus, lymphocyte production is sustained during adult life by quiescent primitive progenitors that divide intermittently. Some, but not all, aspects of the fetal differentiation program are reacquired after chemotherapy.  (+info)

Multipotent adult progenitor cells from swine bone marrow. (8/1106)

We show that multipotent adult progenitor cells (MAPCs) can be derived from both postnatal and fetal swine bone marrow (BM). Although swine MAPC (swMAPC) cultures are initially mixed, cultures are phenotypically homogenous by 50 population doublings (PDs) and can be maintained as such for more than 100 PDs. swMAPCs are negative for CD44, CD45, and major histocompatibility complex (MHC) classes I and II; express octamer binding transcription factor 3a (Oct3a) mRNA and protein at levels close to those seen in human ESCs (hESCs); and have telomerase activity preventing telomere shortening even after 100 PDs. Using quantitative-reverse transcription-polymerase chain reaction (Q-RT-PCR), immunofluorescence, and functional assays, we demonstrate that swMAPCs differentiate into chondrocytes, adipocytes, osteoblasts, smooth muscle cells, endothelium, hepatocyte-like cells, and neuron-like cells. Consistent with what we have shown for human and rodent MAPCs, Q-RT-PCR demonstrated a significant upregulation of transcription factors and other lineage-specific transcripts in a time-dependent fashion similar to development. When swMAPCs were passaged for 3-6 passages at high density (2,000-8,000 cells per cm(2)), Oct3a mRNA levels were no longer detectable, cells acquired the phenotype of mesenchymal stem cells (CD44(+), MHC class I(+)), and could differentiate into typical mesenchymal lineages (adipocytes, osteoblasts, and chondroblasts), but not endothelium, hepatocyte-like cells, or neuron-like cells. Even if cultures were subsequently replated at low density (approximately 100-500 cells per cm(2)) for >20 PDs, Oct3a was not re-expressed, nor were cells capable of differentiating to cells other than mesenchymal-type cells. This suggests that the phenotype and functional characteristics of swMAPCs may not be an in vitro culture phenomenon.  (+info)

Adult stem cells, also known as somatic stem cells, are undifferentiated cells found in specialized tissues or organs throughout the body of a developed organism. Unlike embryonic stem cells, which are derived from blastocysts and have the ability to differentiate into any cell type in the body (pluripotency), adult stem cells are typically more limited in their differentiation potential, meaning they can only give rise to specific types of cells within the tissue or organ where they reside.

Adult stem cells serve to maintain and repair tissues by replenishing dying or damaged cells. They can divide and self-renew over time, producing one daughter cell that remains a stem cell and another that differentiates into a mature, functional cell type. The most well-known adult stem cells are hematopoietic stem cells, which give rise to all types of blood cells, and mesenchymal stem cells, which can differentiate into various connective tissue cells such as bone, cartilage, fat, and muscle.

The potential therapeutic use of adult stem cells has been explored in various medical fields, including regenerative medicine and cancer therapy. However, their limited differentiation capacity and the challenges associated with isolating and expanding them in culture have hindered their widespread application. Recent advances in stem cell research, such as the development of techniques to reprogram adult cells into induced pluripotent stem cells (iPSCs), have opened new avenues for studying and harnessing the therapeutic potential of these cells.

According to the National Institutes of Health (NIH), stem cells are "initial cells" or "precursor cells" that have the ability to differentiate into many different cell types in the body. They can also divide without limit to replenish other cells for as long as the person or animal is still alive.

There are two main types of stem cells: embryonic stem cells, which come from human embryos, and adult stem cells, which are found in various tissues throughout the body. Embryonic stem cells have the ability to differentiate into all cell types in the body, while adult stem cells have more limited differentiation potential.

Stem cells play an essential role in the development and repair of various tissues and organs in the body. They are currently being studied for their potential use in the treatment of a wide range of diseases and conditions, including cancer, diabetes, heart disease, and neurological disorders. However, more research is needed to fully understand the properties and capabilities of these cells before they can be used safely and effectively in clinical settings.

Stem cell transplantation is a medical procedure where stem cells, which are immature and unspecialized cells with the ability to differentiate into various specialized cell types, are introduced into a patient. The main purpose of this procedure is to restore the function of damaged or destroyed tissues or organs, particularly in conditions that affect the blood and immune systems, such as leukemia, lymphoma, aplastic anemia, and inherited metabolic disorders.

There are two primary types of stem cell transplantation: autologous and allogeneic. In autologous transplantation, the patient's own stem cells are collected, stored, and then reinfused back into their body after high-dose chemotherapy or radiation therapy to destroy the diseased cells. In allogeneic transplantation, stem cells are obtained from a donor (related or unrelated) whose human leukocyte antigen (HLA) type closely matches that of the recipient.

The process involves several steps: first, the patient undergoes conditioning therapy to suppress their immune system and make space for the new stem cells. Then, the harvested stem cells are infused into the patient's bloodstream, where they migrate to the bone marrow and begin to differentiate and produce new blood cells. This procedure requires close monitoring and supportive care to manage potential complications such as infections, graft-versus-host disease, and organ damage.

Embryonic stem cells are a type of pluripotent stem cell that are derived from the inner cell mass of a blastocyst, which is a very early-stage embryo. These cells have the ability to differentiate into any cell type in the body, making them a promising area of research for regenerative medicine and the study of human development and disease. Embryonic stem cells are typically obtained from surplus embryos created during in vitro fertilization (IVF) procedures, with the consent of the donors. The use of embryonic stem cells is a controversial issue due to ethical concerns surrounding the destruction of human embryos.

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.

Multipotent stem cells are a type of stem cell that have the ability to differentiate into multiple cell types, but are more limited than pluripotent stem cells. These stem cells are found in various tissues and organs throughout the body, including bone marrow, adipose tissue, and dental pulp. They can give rise to a number of different cell types within their own germ layer (endoderm, mesoderm, or ectoderm), but cannot cross germ layer boundaries. For example, multipotent stem cells found in bone marrow can differentiate into various blood cells such as red and white blood cells, but they cannot differentiate into nerve cells or liver cells. These stem cells play important roles in tissue repair and regeneration, and have potential therapeutic applications in regenerative medicine.

Hematopoietic stem cells (HSCs) are immature, self-renewing cells that give rise to all the mature blood and immune cells in the body. They are capable of both producing more hematopoietic stem cells (self-renewal) and differentiating into early progenitor cells that eventually develop into red blood cells, white blood cells, and platelets. HSCs are found in the bone marrow, umbilical cord blood, and peripheral blood. They have the ability to repair damaged tissues and offer significant therapeutic potential for treating various diseases, including hematological disorders, genetic diseases, and cancer.

Pluripotent stem cells are a type of undifferentiated stem cell that have the ability to differentiate into any cell type of the three germ layers (endoderm, mesoderm, and ectoderm) of a developing embryo. These cells can give rise to all the cell types that make up the human body, with the exception of those that form the extra-embryonic tissues such as the placenta.

Pluripotent stem cells are characterized by their ability to self-renew, which means they can divide and produce more pluripotent stem cells, and differentiate, which means they can give rise to specialized cell types with specific functions. Pluripotent stem cells can be derived from embryos at the blastocyst stage of development or generated in the lab through a process called induced pluripotency, where adult cells are reprogrammed to have the properties of embryonic stem cells.

Pluripotent stem cells hold great promise for regenerative medicine and tissue engineering because they can be used to generate large numbers of specific cell types that can potentially replace or repair damaged or diseased tissues in the body. However, their use is still a subject of ethical debate due to concerns about the source of embryonic stem cells and the potential risks associated with their use in clinical applications.

A stem cell niche is a specific microenvironment in which stem cells reside, interact with surrounding cells and receive molecular signals that regulate their self-renewal, proliferation, differentiation, and survival. This specialized niche provides the necessary conditions for maintaining the undifferentiated state of stem cells and controlling their fate decisions. The components of a stem cell niche typically include various cell types (such as supporting cells, immune cells, and blood vessels), extracellular matrix proteins, signaling molecules, and physical factors like oxygen tension and mechanical stress. Together, these elements create a unique microenvironment that helps to preserve the functional integrity and potential of stem cells for tissue repair, regeneration, and homeostasis.

Mesenchymal Stromal Cells (MSCs) are a type of adult stem cells found in various tissues, including bone marrow, adipose tissue, and umbilical cord blood. They have the ability to differentiate into multiple cell types, such as osteoblasts, chondrocytes, and adipocytes, under specific conditions. MSCs also possess immunomodulatory properties, making them a promising tool in regenerative medicine and therapeutic strategies for various diseases, including autoimmune disorders and tissue injuries. It is important to note that the term "Mesenchymal Stem Cells" has been replaced by "Mesenchymal Stromal Cells" in the scientific community to better reflect their biological characteristics and potential functions.

Planarians are not a medical term, but rather a type of flatworms that belong to the phylum Platyhelminthes. They are known for their ability to regenerate and reproduce asexually. Planarians are often studied in the fields of biology and regenerative medicine due to their unique capacity to regrow lost body parts. However, some planarian species can also be parasitic and infect humans, causing diseases such as intestinal schistosomiasis or cercarial dermatitis. Therefore, while planarians themselves are not a medical term, they have relevance to certain medical fields.

'Cell lineage' is a term used in biology and medicine to describe the developmental history or relationship of a cell or group of cells to other cells, tracing back to the original progenitor or stem cell. It refers to the series of cell divisions and differentiation events that give rise to specific types of cells in an organism over time.

In simpler terms, cell lineage is like a family tree for cells, showing how they are related to each other through a chain of cell division and specialization events. This concept is important in understanding the development, growth, and maintenance of tissues and organs in living beings.

Regeneration in a medical context refers to the process of renewal, restoration, and growth that replaces damaged or missing cells, tissues, organs, or even whole limbs in some organisms. This complex biological process involves various cellular and molecular mechanisms, such as cell proliferation, differentiation, and migration, which work together to restore the structural and functional integrity of the affected area.

In human medicine, regeneration has attracted significant interest due to its potential therapeutic applications in treating various conditions, including degenerative diseases, trauma, and congenital disorders. Researchers are actively studying the underlying mechanisms of regeneration in various model organisms to develop novel strategies for promoting tissue repair and regeneration in humans.

Examples of regeneration in human medicine include liver regeneration after partial hepatectomy, where the remaining liver lobes can grow back to their original size within weeks, and skin wound healing, where keratinocytes migrate and proliferate to close the wound and restore the epidermal layer. However, the regenerative capacity of humans is limited compared to some other organisms, such as planarians and axolotls, which can regenerate entire body parts or even their central nervous system.

Mesenchymal Stem Cell Transplantation (MSCT) is a medical procedure that involves the transplantation of mesenchymal stem cells (MSCs), which are multipotent stromal cells that can differentiate into a variety of cell types, including bone, cartilage, fat, and muscle. These cells can be obtained from various sources, such as bone marrow, adipose tissue, umbilical cord blood, or dental pulp.

In MSCT, MSCs are typically harvested from the patient themselves (autologous transplantation) or from a donor (allogeneic transplantation). The cells are then processed and expanded in a laboratory setting before being injected into the patient's body, usually through an intravenous infusion.

MSCT is being investigated as a potential treatment for a wide range of medical conditions, including degenerative diseases, autoimmune disorders, and tissue injuries. The rationale behind this approach is that MSCs have the ability to migrate to sites of injury or inflammation, where they can help to modulate the immune response, reduce inflammation, and promote tissue repair and regeneration.

However, it's important to note that while MSCT holds promise as a therapeutic option, more research is needed to establish its safety and efficacy for specific medical conditions.

Hematopoietic Stem Cell Transplantation (HSCT) is a medical procedure where hematopoietic stem cells (immature cells that give rise to all blood cell types) are transplanted into a patient. This procedure is often used to treat various malignant and non-malignant disorders affecting the hematopoietic system, such as leukemias, lymphomas, multiple myeloma, aplastic anemia, inherited immune deficiency diseases, and certain genetic metabolic disorders.

The transplantation can be autologous (using the patient's own stem cells), allogeneic (using stem cells from a genetically matched donor, usually a sibling or unrelated volunteer), or syngeneic (using stem cells from an identical twin).

The process involves collecting hematopoietic stem cells, most commonly from the peripheral blood or bone marrow. The collected cells are then infused into the patient after the recipient's own hematopoietic system has been ablated (or destroyed) using high-dose chemotherapy and/or radiation therapy. This allows the donor's stem cells to engraft, reconstitute, and restore the patient's hematopoietic system.

HSCT is a complex and potentially risky procedure with various complications, including graft-versus-host disease, infections, and organ damage. However, it offers the potential for cure or long-term remission in many patients with otherwise fatal diseases.

Regenerative medicine is a branch of medicine that deals with the repair or replacement of damaged or diseased cells, tissues, and organs using various strategies, including the use of stem cells, tissue engineering, gene therapy, and biomaterials. The goal of regenerative medicine is to restore normal function and structure to tissues and organs, thereby improving the patient's quality of life and potentially curing diseases that were previously considered incurable.

Regenerative medicine has shown promise in a variety of clinical applications, such as the treatment of degenerative diseases like osteoarthritis, spinal cord injuries, heart disease, diabetes, and liver failure. It also holds great potential for use in regenerative therapies for wound healing, tissue reconstruction, and cosmetic surgery.

The field of regenerative medicine is rapidly evolving, with new discoveries and advances being made regularly. As our understanding of the underlying biological mechanisms that drive tissue repair and regeneration continues to grow, so too will the potential clinical applications of this exciting and promising field.

Stem cell research is a branch of medical science that focuses on the study and application of stem cells, which are undifferentiated or unspecialized cells with the ability to differentiate into various specialized cell types in the body. These cells have the potential to regenerate and repair damaged tissues and organs, making them a promising area of research for the development of new treatments for a wide range of diseases and conditions, including cancer, neurodegenerative disorders, diabetes, heart disease, and more.

Stem cell research involves several key areas, such as:

1. Isolation and culture: Scientists isolate stem cells from various sources, such as embryos, umbilical cord blood, or adult tissues, and grow them in a lab to study their properties and behaviors.
2. Differentiation: Researchers induce stem cells to differentiate into specific cell types, such as heart cells, brain cells, or pancreatic cells, by exposing them to various growth factors and other chemical signals.
3. Genetic modification: Scientists may modify the genes of stem cells to enhance their therapeutic potential or to study the effects of genetic mutations on cell behavior and development.
4. Transplantation: In some cases, researchers transplant stem cells into animal models or human patients to investigate their ability to repair damaged tissues and organs.
5. Ethical considerations: Stem cell research raises several ethical concerns related to the use of embryonic stem cells, which are derived from human embryos. These concerns have led to ongoing debates about the limits and regulations surrounding this area of research.

Overall, stem cell research holds great promise for the development of new medical treatments and therapies, but it also requires careful consideration of ethical issues and rigorous scientific investigation to ensure its safety and effectiveness.

Induced Pluripotent Stem Cells (iPSCs) are a type of pluripotent stem cells that are generated from somatic cells, such as skin or blood cells, through the introduction of specific genes encoding transcription factors. These reprogrammed cells exhibit similar characteristics to embryonic stem cells, including the ability to differentiate into any cell type of the three germ layers (endoderm, mesoderm, and ectoderm). The discovery and development of iPSCs have opened up new possibilities in regenerative medicine, drug testing and development, and disease modeling, while avoiding ethical concerns associated with embryonic stem cells.

Neural stem cells (NSCs) are a type of undifferentiated cells found in the central nervous system, including the brain and spinal cord. They have the ability to self-renew and generate the main types of cells found in the nervous system, such as neurons, astrocytes, and oligodendrocytes. NSCs are capable of dividing symmetrically to increase their own population or asymmetrically to produce one stem cell and one differentiated cell. They play a crucial role in the development and maintenance of the nervous system, and have the potential to be used in regenerative medicine and therapies for neurological disorders and injuries.

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.

Cell culture is a technique used in scientific research to grow and maintain cells from plants, animals, or humans in a controlled environment outside of their original organism. This environment typically consists of a sterile container called a cell culture flask or plate, and a nutrient-rich liquid medium that provides the necessary components for the cells' growth and survival, such as amino acids, vitamins, minerals, and hormones.

There are several different types of cell culture techniques used in research, including:

1. Adherent cell culture: In this technique, cells are grown on a flat surface, such as the bottom of a tissue culture dish or flask. The cells attach to the surface and spread out, forming a monolayer that can be observed and manipulated under a microscope.
2. Suspension cell culture: In suspension culture, cells are grown in liquid medium without any attachment to a solid surface. These cells remain suspended in the medium and can be agitated or mixed to ensure even distribution of nutrients.
3. Organoid culture: Organoids are three-dimensional structures that resemble miniature organs and are grown from stem cells or other progenitor cells. They can be used to study organ development, disease processes, and drug responses.
4. Co-culture: In co-culture, two or more different types of cells are grown together in the same culture dish or flask. This technique is used to study cell-cell interactions and communication.
5. Conditioned medium culture: In this technique, cells are grown in a medium that has been conditioned by previous cultures of other cells. The conditioned medium contains factors secreted by the previous cells that can influence the growth and behavior of the new cells.

Cell culture techniques are widely used in biomedical research to study cellular processes, develop drugs, test toxicity, and investigate disease mechanisms. However, it is important to note that cell cultures may not always accurately represent the behavior of cells in a living organism, and results from cell culture experiments should be validated using other methods.

Cell-and tissue-based therapy is a type of medical treatment that involves the use of living cells or tissues to repair, replace, or regenerate damaged or diseased cells or tissues in the body. This can include the transplantation of stem cells, which are immature cells that have the ability to develop into different types of cells, as well as the use of fully differentiated cells or tissues that have specific functions in the body.

Cell-and tissue-based therapies may be used to treat a wide variety of medical conditions, including degenerative diseases, injuries, and congenital defects. Some examples of cell-and tissue-based therapies include:

* Bone marrow transplantation: This involves the transplantation of blood-forming stem cells from the bone marrow of a healthy donor to a patient in need of new blood cells due to disease or treatment with chemotherapy or radiation.
* Corneal transplantation: This involves the transplantation of healthy corneal tissue from a deceased donor to a patient with damaged or diseased corneas.
* Articular cartilage repair: This involves the use of cells or tissues to repair damaged articular cartilage, which is the smooth, white tissue that covers the ends of bones where they come together to form joints.

Cell-and tissue-based therapies are a rapidly evolving field of medicine, and researchers are continually exploring new ways to use these treatments to improve patient outcomes. However, it is important to note that cell-and tissue-based therapies also carry some risks, including the possibility of rejection or infection, and they should only be performed by qualified medical professionals in appropriate settings.

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.

"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.

Fetal stem cells are a type of stem cell that are derived from fetal tissue, which is tissue obtained from an elective abortion or a spontaneous miscarriage. These stem cells have the ability to differentiate into various cell types, including neurons, cardiac muscle cells, and hepatocytes (liver cells). Fetal stem cells are unique in that they have a greater capacity for self-renewal and can generate a larger number of differentiated cells compared to adult stem cells. They also have the potential to be less immunogenic than other types of stem cells, making them a promising candidate for cell-based therapies and regenerative medicine. However, the use of fetal stem cells is a subject of ethical debate due to their source.

Cell separation is a process used to separate and isolate specific cell types from a heterogeneous mixture of cells. This can be accomplished through various physical or biological methods, depending on the characteristics of the cells of interest. Some common techniques for cell separation include:

1. Density gradient centrifugation: In this method, a sample containing a mixture of cells is layered onto a density gradient medium and then centrifuged. The cells are separated based on their size, density, and sedimentation rate, with denser cells settling closer to the bottom of the tube and less dense cells remaining near the top.

2. Magnetic-activated cell sorting (MACS): This technique uses magnetic beads coated with antibodies that bind to specific cell surface markers. The labeled cells are then passed through a column placed in a magnetic field, which retains the magnetically labeled cells while allowing unlabeled cells to flow through.

3. Fluorescence-activated cell sorting (FACS): In this method, cells are stained with fluorochrome-conjugated antibodies that recognize specific cell surface or intracellular markers. The stained cells are then passed through a laser beam, which excites the fluorophores and allows for the detection and sorting of individual cells based on their fluorescence profile.

4. Filtration: This simple method relies on the physical size differences between cells to separate them. Cells can be passed through filters with pore sizes that allow smaller cells to pass through while retaining larger cells.

5. Enzymatic digestion: In some cases, cells can be separated by enzymatically dissociating tissues into single-cell suspensions and then using various separation techniques to isolate specific cell types.

These methods are widely used in research and clinical settings for applications such as isolating immune cells, stem cells, or tumor cells from biological samples.

Neoplastic stem cells, also known as cancer stem cells (CSCs), are a subpopulation of cells within a tumor that are capable of self-renewal and generating the heterogeneous lineages of cells that comprise the tumor. These cells are believed to be responsible for the initiation, maintenance, and progression of cancer, as well as its recurrence and resistance to therapy.

CSCs share some similarities with normal stem cells, such as their ability to divide asymmetrically and give rise to differentiated progeny. However, they also have distinct characteristics that distinguish them from their normal counterparts, including aberrant gene expression, altered signaling pathways, and increased resistance to apoptosis (programmed cell death).

The existence of CSCs has important implications for cancer diagnosis, treatment, and prevention. Targeting these cells specifically may be necessary to achieve durable remissions and prevent relapse, as they are thought to survive conventional therapies that target the bulk of the tumor. Further research is needed to better understand the biology of CSCs and develop effective strategies for their elimination.

Premature aging, also known as "accelerated aging" or "early aging," refers to the physiological process in which the body shows signs of aging at an earlier age than typically expected. This can include various symptoms such as wrinkles, graying hair, decreased energy and mobility, cognitive decline, and increased risk of chronic diseases.

The medical definition of premature aging is not well-established, as aging is a complex process influenced by a variety of genetic and environmental factors. However, certain conditions and syndromes are associated with premature aging, such as Hutchinson-Gilford progeria syndrome, Werner syndrome, and Down syndrome.

In general, the signs of premature aging may be caused by a combination of genetic predisposition, lifestyle factors (such as smoking, alcohol consumption, and poor diet), exposure to environmental toxins, and chronic stress. While some aspects of aging are inevitable, maintaining a healthy lifestyle and reducing exposure to harmful factors can help slow down the aging process and improve overall quality of life.

Stem Cell Factor (SCF), also known as Kit Ligand or Steel Factor, is a growth factor that plays a crucial role in the regulation of hematopoiesis, which is the process of producing various blood cells. It is a glycoprotein that binds to the c-Kit receptor found on hematopoietic stem cells and progenitor cells, promoting their survival, proliferation, and differentiation into mature blood cells.

SCF is involved in the development and function of several types of blood cells, including red blood cells, white blood cells, and platelets. It also plays a role in the maintenance and self-renewal of hematopoietic stem cells, which are essential for the continuous production of new blood cells throughout an individual's lifetime.

In addition to its role in hematopoiesis, SCF has been implicated in various other biological processes, such as melanogenesis, gametogenesis, and tissue repair and regeneration. Dysregulation of SCF signaling has been associated with several diseases, including certain types of cancer, bone marrow failure disorders, and autoimmune diseases.

Tissue engineering is a branch of biomedical engineering that combines the principles of engineering, materials science, and biological sciences to develop functional substitutes for damaged or diseased tissues and organs. It involves the creation of living, three-dimensional structures that can restore, maintain, or improve tissue function. This is typically accomplished through the use of cells, scaffolds (biodegradable matrices), and biologically active molecules. The goal of tissue engineering is to develop biological substitutes that can ultimately restore normal function and structure in damaged tissues or organs.

A hair follicle is a part of the human skin from which hair grows. It is a complex organ that consists of several layers, including an outer root sheath, inner root sheath, and matrix. The hair follicle is located in the dermis, the second layer of the skin, and is surrounded by sebaceous glands and erector pili muscles.

The hair growth cycle includes three phases: anagen (growth phase), catagen (transitional phase), and telogen (resting phase). During the anagen phase, cells in the matrix divide rapidly to produce new hair fibers that grow out of the follicle. The hair fiber is made up of a protein called keratin, which also makes up the outer layers of the skin and nails.

Hair follicles are important for various biological functions, including thermoregulation, sensory perception, and social communication. They also play a role in wound healing and can serve as a source of stem cells that can differentiate into other cell types.

Octamer Transcription Factor-3 (OTF-3 or Oct3) is a specific protein that belongs to the class of POU domain transcription factors. These proteins play crucial roles in the regulation of gene expression during cell growth, development, and differentiation. The "POU" name refers to the presence of two conserved domains - a POU-specific domain and a POU homeodomain - that recognize and bind to specific DNA sequences called octamer motifs, which are involved in controlling the transcription of target genes.

Oct3, encoded by the Pou2f1 gene, is widely expressed in various tissues, including lymphoid cells, neurons, and embryonic stem cells. It has been shown to regulate the expression of several genes that are essential for cell survival, proliferation, and differentiation. Dysregulation of Oct3 has been implicated in several diseases, such as cancers and neurological disorders.

In summary, Octamer Transcription Factor-3 (Oct3) is a POU domain transcription factor that binds to octamer motifs in DNA and regulates the expression of target genes involved in cell growth, development, and differentiation.

Spermatogonia are a type of diploid germ cells found in the seminiferous tubules of the testis. They are the stem cells responsible for sperm production (spermatogenesis) in males. There are two types of spermatogonia: A-dark (Ad) and A-pale (Ap). The Ad spermatogonia function as reserve stem cells, while the Ap spermatogonia serve as the progenitor cells that divide to produce type B spermatogonia. Type B spermatogonia then differentiate into primary spermatocytes, which undergo meiosis to form haploid spermatozoa.

Cellular aging, also known as cellular senescence, is a natural process that occurs as cells divide and grow older. Over time, cells accumulate damage to their DNA, proteins, and lipids due to various factors such as genetic mutations, oxidative stress, and epigenetic changes. This damage can impair the cell's ability to function properly and can lead to changes associated with aging, such as decreased tissue repair and regeneration, increased inflammation, and increased risk of age-related diseases.

Cellular aging is characterized by several features, including:

1. Shortened telomeres: Telomeres are the protective caps on the ends of chromosomes that shorten each time a cell divides. When telomeres become too short, the cell can no longer divide and becomes senescent or dies.
2. Epigenetic changes: Epigenetic modifications refer to chemical changes to DNA and histone proteins that affect gene expression without changing the underlying genetic code. As cells age, they accumulate epigenetic changes that can alter gene expression and contribute to cellular aging.
3. Oxidative stress: Reactive oxygen species (ROS) are byproducts of cellular metabolism that can damage DNA, proteins, and lipids. Accumulated ROS over time can lead to oxidative stress, which is associated with cellular aging.
4. Inflammation: Senescent cells produce pro-inflammatory cytokines, chemokines, and matrix metalloproteinases that contribute to a low-grade inflammation known as inflammaging. This chronic inflammation can lead to tissue damage and increase the risk of age-related diseases.
5. Genomic instability: DNA damage accumulates with age, leading to genomic instability and an increased risk of mutations and cancer.

Understanding cellular aging is crucial for developing interventions that can delay or prevent age-related diseases and improve healthy lifespan.

Dental pulp is the soft tissue located in the center of a tooth, surrounded by the dentin. It contains nerves, blood vessels, and connective tissue, and plays a vital role in the development and health of the tooth. The dental pulp helps to form dentin during tooth development and continues to provide nourishment to the tooth throughout its life. It also serves as a sensory organ, allowing the tooth to detect hot and cold temperatures and transmit pain signals to the brain. Injury or infection of the dental pulp can lead to serious dental problems, such as tooth decay or abscesses, and may require root canal treatment to remove the damaged tissue and save the tooth.

Germ cells are the reproductive cells, also known as sex cells, that combine to form offspring in sexual reproduction. In females, germ cells are called ova or egg cells, and in males, they are called spermatozoa or sperm cells. These cells are unique because they carry half the genetic material necessary for creating new life. They are produced through a process called meiosis, which reduces their chromosome number by half, ensuring that when two germ cells combine during fertilization, the normal diploid number of chromosomes is restored.

Chondrogenesis is the process of cartilage formation during embryonic development and in the healing of certain types of injuries. It involves the differentiation of mesenchymal stem cells into chondrocytes, which are the specialized cells that produce and maintain the extracellular matrix of cartilage.

During chondrogenesis, the mesenchymal stem cells condense and form a template for the future cartilaginous tissue. These cells then differentiate into chondrocytes, which begin to produce and deposit collagen type II, proteoglycans, and other extracellular matrix components that give cartilage its unique biochemical and mechanical properties.

Chondrogenesis is a critical process for the development of various structures in the body, including the skeletal system, where it plays a role in the formation of articular cartilage, growth plates, and other types of cartilage. Understanding the molecular mechanisms that regulate chondrogenesis is important for developing therapies to treat cartilage injuries and degenerative diseases such as osteoarthritis.

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.

Cell transplantation is the process of transferring living cells from one part of the body to another or from one individual to another. In medicine, cell transplantation is often used as a treatment for various diseases and conditions, including neurodegenerative disorders, diabetes, and certain types of cancer. The goal of cell transplantation is to replace damaged or dysfunctional cells with healthy ones, thereby restoring normal function to the affected area.

In the context of medical research, cell transplantation may involve the use of stem cells, which are immature cells that have the ability to develop into many different types of specialized cells. Stem cell transplantation has shown promise in the treatment of a variety of conditions, including spinal cord injuries, stroke, and heart disease.

It is important to note that cell transplantation carries certain risks, such as immune rejection and infection. As such, it is typically reserved for cases where other treatments have failed or are unlikely to be effective.

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.

A plant stem is not typically defined in a medical context, but rather in the field of botany. However, I can certainly provide a general biological definition for you.

In plants, stems are organs that serve primarily as support structures, holding leaves, flowers, and fruits aloft where they can receive sunlight and exchange gases. They also act as conduits, transporting water, nutrients, and sugars made during photosynthesis between the roots and shoots of a plant.

The stem is usually composed of three main tissue systems: dermal, vascular, and ground. The dermal tissue system forms the outermost layer(s) of the stem, providing protection and sometimes participating in gas exchange. The vascular tissue system contains the xylem (which transports water and nutrients upward) and phloem (which transports sugars and other organic compounds downward). The ground tissue system, located between the dermal and vascular tissues, is responsible for food storage and support.

While not a direct medical definition, understanding the structure and function of plant stems can be relevant in fields such as nutrition, agriculture, and environmental science, which have implications for human health.

Cell dedifferentiation is a process by which a mature, specialized cell reverts back to an earlier stage in its developmental lineage, regaining the ability to divide and differentiate into various cell types. This phenomenon is typically observed in cells that have been damaged or injured, as well as during embryonic development and certain disease states like cancer. In the context of tissue repair and regeneration, dedifferentiation allows for the generation of new cells with the potential to replace lost or damaged tissues. However, uncontrolled dedifferentiation can also contribute to tumor formation and progression.

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.

A mammalian embryo is the developing offspring of a mammal, from the time of implantation of the fertilized egg (blastocyst) in the uterus until the end of the eighth week of gestation. During this period, the embryo undergoes rapid cell division and organ differentiation to form a complex structure with all the major organs and systems in place. This stage is followed by fetal development, which continues until birth. The study of mammalian embryos is important for understanding human development, evolution, and reproductive biology.

Satellite cells in skeletal muscle are undifferentiated stem cells that are crucial for postnatal growth, maintenance, and repair of skeletal muscle. They are located between the basal lamina and plasma membrane of myofibers. In response to muscle damage or injury, satellite cells become activated, proliferate, differentiate into myoblasts, fuse with existing muscle fibers, and contribute to muscle regeneration. Satellite cells also play a role in maintaining muscle homeostasis by fusing with mature muscle fibers to replace damaged proteins and organelles. They are essential for the adaptation of skeletal muscle to various stimuli such as exercise or mechanical load.

SOXB1 transcription factors are a subgroup of the SOX (SRY-related HMG box) family of transcription factors, which are characterized by a conserved high mobility group (HMG) box DNA-binding domain. The SOXB1 subfamily includes SOX1, SOX2, and SOX3, which play crucial roles during embryonic development and in the maintenance of stem cells. They regulate gene expression by binding to specific DNA sequences and interacting with other transcription factors and cofactors. SOXB1 proteins have been implicated in various biological processes, such as neurogenesis, eye development, and sex determination. Dysregulation of SOXB1 transcription factors has been associated with several human diseases, including cancer.

Developmental gene expression regulation refers to the processes that control the activation or repression of specific genes during embryonic and fetal development. These regulatory mechanisms ensure that genes are expressed at the right time, in the right cells, and at appropriate levels to guide proper growth, differentiation, and morphogenesis of an organism.

Developmental gene expression regulation is a complex and dynamic process involving various molecular players, such as transcription factors, chromatin modifiers, non-coding RNAs, and signaling molecules. These regulators can interact with cis-regulatory elements, like enhancers and promoters, to fine-tune the spatiotemporal patterns of gene expression during development.

Dysregulation of developmental gene expression can lead to various congenital disorders and developmental abnormalities. Therefore, understanding the principles and mechanisms governing developmental gene expression regulation is crucial for uncovering the etiology of developmental diseases and devising potential therapeutic strategies.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Adipogenesis is the process by which precursor cells differentiate into mature adipocytes, or fat cells. This complex biological process involves a series of molecular and cellular events that are regulated by various genetic and epigenetic factors.

During adipogenesis, preadipocytes undergo a series of changes that include cell cycle arrest, morphological alterations, and the expression of specific genes that are involved in lipid metabolism and insulin sensitivity. These changes ultimately result in the formation of mature adipocytes that are capable of storing energy in the form of lipids.

Abnormalities in adipogenesis have been linked to various health conditions, including obesity, type 2 diabetes, and metabolic syndrome. Understanding the molecular mechanisms that regulate adipogenesis is an active area of research, as it may lead to the development of new therapies for these and other related diseases.

Autologous transplantation is a medical procedure where cells, tissues, or organs are removed from a person, stored and then returned back to the same individual at a later time. This is different from allogeneic transplantation where the tissue or organ is obtained from another donor. The term "autologous" is derived from the Greek words "auto" meaning self and "logos" meaning study.

In autologous transplantation, the patient's own cells or tissues are used to replace or repair damaged or diseased ones. This reduces the risk of rejection and eliminates the need for immunosuppressive drugs, which are required in allogeneic transplants to prevent the body from attacking the foreign tissue.

Examples of autologous transplantation include:

* Autologous bone marrow or stem cell transplantation, where stem cells are removed from the patient's blood or bone marrow, stored and then reinfused back into the same individual after high-dose chemotherapy or radiation therapy to treat cancer.
* Autologous skin grafting, where a piece of skin is taken from one part of the body and transplanted to another area on the same person.
* Autologous chondrocyte implantation, where cartilage cells are harvested from the patient's own knee, cultured in a laboratory and then implanted back into the knee to repair damaged cartilage.

Stromal cells, also known as stromal/stroma cells, are a type of cell found in various tissues and organs throughout the body. They are often referred to as the "connective tissue" or "supporting framework" of an organ because they play a crucial role in maintaining the structure and function of the tissue. Stromal cells include fibroblasts, adipocytes (fat cells), and various types of progenitor/stem cells. They produce and maintain the extracellular matrix, which is the non-cellular component of tissues that provides structural support and biochemical cues for other cells. Stromal cells also interact with immune cells and participate in the regulation of the immune response. In some contexts, "stromal cells" can also refer to cells found in the microenvironment of tumors, which can influence cancer growth and progression.

Nestin is a type of class VI intermediate filament protein that is primarily expressed in various types of undifferentiated or progenitor cells in the nervous system, including neural stem cells and progenitor cells. It is often used as a marker for these cells due to its expression during stages of active cell division and migration. Nestin is also expressed in some other tissues undergoing regeneration or injury.

Green Fluorescent Protein (GFP) is not a medical term per se, but a scientific term used in the field of molecular biology. GFP is a protein that exhibits bright green fluorescence when exposed to light, particularly blue or ultraviolet light. It was originally discovered in the jellyfish Aequorea victoria.

In medical and biological research, scientists often use recombinant DNA technology to introduce the gene for GFP into other organisms, including bacteria, plants, and animals, including humans. This allows them to track the expression and localization of specific genes or proteins of interest in living cells, tissues, or even whole organisms.

The ability to visualize specific cellular structures or processes in real-time has proven invaluable for a wide range of research areas, from studying the development and function of organs and organ systems to understanding the mechanisms of diseases and the effects of therapeutic interventions.

Gene expression profiling is a laboratory technique used to measure the activity (expression) of thousands of genes at once. This technique allows researchers and clinicians to identify which genes are turned on or off in a particular cell, tissue, or organism under specific conditions, such as during health, disease, development, or in response to various treatments.

The process typically involves isolating RNA from the cells or tissues of interest, converting it into complementary DNA (cDNA), and then using microarray or high-throughput sequencing technologies to determine which genes are expressed and at what levels. The resulting data can be used to identify patterns of gene expression that are associated with specific biological states or processes, providing valuable insights into the underlying molecular mechanisms of diseases and potential targets for therapeutic intervention.

In recent years, gene expression profiling has become an essential tool in various fields, including cancer research, drug discovery, and personalized medicine, where it is used to identify biomarkers of disease, predict patient outcomes, and guide treatment decisions.

Hematopoietic Stem Cell Mobilization is the process of mobilizing hematopoietic stem cells (HSCs) from the bone marrow into the peripheral blood. HSCs are immature cells that have the ability to differentiate into all types of blood cells, including red and white blood cells and platelets.

Mobilization is often achieved through the use of medications such as granulocyte-colony stimulating factor (G-CSF) or plerixafor, which stimulate the release of HSCs from the bone marrow into the peripheral blood. This allows for the collection of HSCs from the peripheral blood through a procedure called apheresis.

Mobilized HSCs can be used in stem cell transplantation procedures to reconstitute a patient's hematopoietic system after high-dose chemotherapy or radiation therapy. It is an important process in the field of regenerative medicine and has been used to treat various diseases such as leukemia, lymphoma, and sickle cell disease.

CD34 is a type of antigen that is found on the surface of certain cells in the human body. Specifically, CD34 antigens are present on hematopoietic stem cells, which are immature cells that can develop into different types of blood cells. These stem cells are found in the bone marrow and are responsible for producing red blood cells, white blood cells, and platelets.

CD34 antigens are a type of cell surface marker that is used in medical research and clinical settings to identify and isolate hematopoietic stem cells. They are also used in the development of stem cell therapies and transplantation procedures. CD34 antigens can be detected using various laboratory techniques, such as flow cytometry or immunohistochemistry.

It's important to note that while CD34 is a useful marker for identifying hematopoietic stem cells, it is not exclusive to these cells and can also be found on other cell types, such as endothelial cells that line blood vessels. Therefore, additional markers are often used in combination with CD34 to more specifically identify and isolate hematopoietic stem cells.

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.

Adipose tissue, also known as fatty tissue, is a type of connective tissue that is composed mainly of adipocytes (fat cells). It is found throughout the body, but is particularly abundant in the abdominal cavity, beneath the skin, and around organs such as the heart and kidneys.

Adipose tissue serves several important functions in the body. One of its primary roles is to store energy in the form of fat, which can be mobilized and used as an energy source during periods of fasting or exercise. Adipose tissue also provides insulation and cushioning for the body, and produces hormones that help regulate metabolism, appetite, and reproductive function.

There are two main types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is the more common form and is responsible for storing energy as fat. BAT, on the other hand, contains a higher number of mitochondria and is involved in heat production and energy expenditure.

Excessive accumulation of adipose tissue can lead to obesity, which is associated with an increased risk of various health problems such as diabetes, heart disease, and certain types of cancer.

A Colony-Forming Units (CFU) assay is a type of laboratory test used to measure the number of viable, or living, cells in a sample. It is commonly used to enumerate bacteria, yeast, and other microorganisms. The test involves placing a known volume of the sample onto a nutrient-agar plate, which provides a solid growth surface for the cells. The plate is then incubated under conditions that allow the cells to grow and form colonies. Each colony that forms on the plate represents a single viable cell from the original sample. By counting the number of colonies and multiplying by the known volume of the sample, the total number of viable cells in the sample can be calculated. This information is useful in a variety of applications, including monitoring microbial populations, assessing the effectiveness of disinfection procedures, and studying microbial growth and survival.

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.

Cell transdifferentiation is a process in which one type of differentiated cell transforms into another type of differentiated cell, without going through the stage of pluripotent stem cells. This process involves a series of genetic and epigenetic changes that result in the activation of new genetic programs and repression of old ones, leading to the acquisition of a new cell identity.

Transdifferentiation is a rare event in nature, but it has been induced in the laboratory through various methods such as gene transfer, chemical treatment, or nuclear transplantation. This process has potential applications in regenerative medicine, tissue engineering, and disease modeling. However, it also raises ethical concerns related to the generation of chimeric organisms and the possibility of uncontrolled cell growth.

A lentivirus is a type of slow-acting retrovirus that can cause chronic diseases and cancers. The term "lentivirus" comes from the Latin word "lentus," which means slow. Lentiviruses are characterized by their ability to establish a persistent infection, during which they continuously produce new viral particles.

Lentiviruses have a complex genome that includes several accessory genes, in addition to the typical gag, pol, and env genes found in all retroviruses. These accessory genes play important roles in regulating the virus's replication cycle and evading the host's immune response.

One of the most well-known lentiviruses is the human immunodeficiency virus (HIV), which causes AIDS. Other examples include the feline immunodeficiency virus (FIV) and the simian immunodeficiency virus (SIV). Lentiviruses have also been used as vectors for gene therapy, as they can efficiently introduce new genes into both dividing and non-dividing cells.

'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.

Tissue scaffolds, also known as bioactive scaffolds or synthetic extracellular matrices, refer to three-dimensional structures that serve as templates for the growth and organization of cells in tissue engineering and regenerative medicine. These scaffolds are designed to mimic the natural extracellular matrix (ECM) found in biological tissues, providing a supportive environment for cell attachment, proliferation, differentiation, and migration.

Tissue scaffolds can be made from various materials, including naturally derived biopolymers (e.g., collagen, alginate, chitosan, hyaluronic acid), synthetic polymers (e.g., polycaprolactone, polylactic acid, poly(lactic-co-glycolic acid)), or a combination of both. The choice of material depends on the specific application and desired properties, such as biocompatibility, biodegradability, mechanical strength, and porosity.

The primary functions of tissue scaffolds include:

1. Cell attachment: Providing surfaces for cells to adhere, spread, and form stable focal adhesions.
2. Mechanical support: Offering a structural framework that maintains the desired shape and mechanical properties of the engineered tissue.
3. Nutrient diffusion: Ensuring adequate transport of nutrients, oxygen, and waste products throughout the scaffold to support cell survival and function.
4. Guided tissue growth: Directing the organization and differentiation of cells through spatial cues and biochemical signals.
5. Biodegradation: Gradually degrading at a rate that matches tissue regeneration, allowing for the replacement of the scaffold with native ECM produced by the cells.

Tissue scaffolds have been used in various applications, such as wound healing, bone and cartilage repair, cardiovascular tissue engineering, and neural tissue regeneration. The design and fabrication of tissue scaffolds are critical aspects of tissue engineering, aiming to create functional substitutes for damaged or diseased tissues and organs.

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.

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.

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).

High Mobility Group Box 3 (HMGB3) protein, also known as HMG-IY, is a member of the high mobility group box (HMGB) family of proteins. These proteins are characterized by their ability to bind to DNA and function as architectural factors in the regulation of gene transcription, DNA replication, and repair.

HMGB3 protein is widely expressed in various tissues, including the testis, brain, heart, lung, liver, skeletal muscle, and kidney. It has been implicated in several biological processes, such as embryonic development, cell differentiation, and tumorigenesis. HMGB3 can act as a transcriptional regulator by binding to specific DNA sequences and interacting with other proteins involved in gene expression.

In cancer, HMGB3 has been found to be overexpressed in several types of malignancies, including hepatocellular carcinoma, colorectal cancer, gastric cancer, and breast cancer. High levels of HMGB3 have been associated with poor prognosis, increased tumor growth, and metastasis. Therefore, HMGB3 is considered a potential therapeutic target for cancer treatment.

Progeria, also known as Hutchinson-Gilford Progeria Syndrome (HGPS), is a rare and fatal genetic condition characterized by the rapid aging of children. The term "progeria" comes from the Greek words "pro," meaning prematurely, and "gereas," meaning old age.

Individuals with progeria typically appear normal at birth but begin to display signs of accelerated aging within the first two years of life. These symptoms can include growth failure, loss of body fat and hair, aged-looking skin, joint stiffness, hip dislocation, and cardiovascular disease. The most common cause of death in progeria patients is heart attack or stroke due to widespread atherosclerosis (the hardening and narrowing of the arteries).

Progeria is caused by a mutation in the LMNA gene, which provides instructions for making a protein called lamin A. This protein is essential for the structure and function of the nuclear envelope, the membrane that surrounds the cell's nucleus. The mutation leads to the production of an abnormal form of lamin A called progerin, which accumulates in cells throughout the body, causing premature aging.

There is currently no cure for progeria, and treatment is focused on managing symptoms and complications. Researchers are actively studying potential treatments that could slow or reverse the effects of the disease.

Transgenic mice are genetically modified rodents that have incorporated foreign DNA (exogenous DNA) into their own genome. This is typically done through the use of recombinant DNA technology, where a specific gene or genetic sequence of interest is isolated and then introduced into the mouse embryo. The resulting transgenic mice can then express the protein encoded by the foreign gene, allowing researchers to study its function in a living organism.

The process of creating transgenic mice usually involves microinjecting the exogenous DNA into the pronucleus of a fertilized egg, which is then implanted into a surrogate mother. The offspring that result from this procedure are screened for the presence of the foreign DNA, and those that carry the desired genetic modification are used to establish a transgenic mouse line.

Transgenic mice have been widely used in biomedical research to model human diseases, study gene function, and test new therapies. They provide a valuable tool for understanding complex biological processes and developing new treatments for a variety of medical conditions.

Epigenetics is the study of heritable changes in gene function that occur without a change in the underlying DNA sequence. These changes can be caused by various mechanisms such as DNA methylation, histone modification, and non-coding RNA molecules. Epigenetic changes can be influenced by various factors including age, environment, lifestyle, and disease state.

Genetic epigenesis specifically refers to the study of how genetic factors influence these epigenetic modifications. Genetic variations between individuals can lead to differences in epigenetic patterns, which in turn can contribute to phenotypic variation and susceptibility to diseases. For example, certain genetic variants may predispose an individual to develop cancer, and environmental factors such as smoking or exposure to chemicals can interact with these genetic variants to trigger epigenetic changes that promote tumor growth.

Overall, the field of genetic epigenesis aims to understand how genetic and environmental factors interact to regulate gene expression and contribute to disease susceptibility.

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.

Wnt proteins are a family of secreted signaling molecules that play crucial roles in the regulation of fundamental biological processes, including cell proliferation, differentiation, migration, and survival. They were first discovered in 1982 through genetic studies in Drosophila melanogaster (fruit flies) and have since been found to be highly conserved across various species, from invertebrates to humans.

Wnt proteins exert their effects by binding to specific receptors on the target cell surface, leading to the activation of several intracellular signaling pathways:

1. Canonical Wnt/β-catenin pathway: In the absence of Wnt ligands, β-catenin is continuously degraded by a destruction complex consisting of Axin, APC (Adenomatous polyposis coli), and GSK3β (Glycogen synthase kinase 3 beta). When Wnt proteins bind to their receptors Frizzled and LRP5/6, the formation of a "signalosome" complex leads to the inhibition of the destruction complex, allowing β-catenin to accumulate in the cytoplasm and translocate into the nucleus. Here, it interacts with TCF/LEF (T-cell factor/lymphoid enhancer-binding factor) transcription factors to regulate the expression of target genes involved in cell proliferation, differentiation, and survival.
2. Non-canonical Wnt pathways: These include the Wnt/Ca^2+^ pathway and the planar cell polarity (PCP) pathway. In the Wnt/Ca^2+^ pathway, Wnt ligands bind to Frizzled receptors and activate heterotrimeric G proteins, leading to an increase in intracellular Ca^2+^ levels and activation of downstream targets such as protein kinase C (PKC) and calcium/calmodulin-dependent protein kinase II (CAMKII). These signaling events ultimately regulate cell movement, adhesion, and gene expression. In the PCP pathway, Wnt ligands bind to Frizzled receptors and coreceptor complexes containing Ror2 or Ryk, leading to activation of small GTPases such as RhoA and Rac1, which control cytoskeletal organization and cell polarity.

Dysregulation of Wnt signaling has been implicated in various human diseases, including cancer, developmental disorders, and degenerative conditions. In cancer, aberrant activation of the canonical Wnt/β-catenin pathway contributes to tumor initiation, progression, and metastasis by promoting cell proliferation, survival, and epithelial-mesenchymal transition (EMT). Inhibitors targeting different components of the Wnt signaling pathway are currently being developed as potential therapeutic strategies for cancer treatment.

Coculture techniques refer to a type of experimental setup in which two or more different types of cells or organisms are grown and studied together in a shared culture medium. This method allows researchers to examine the interactions between different cell types or species under controlled conditions, and to study how these interactions may influence various biological processes such as growth, gene expression, metabolism, and signal transduction.

Coculture techniques can be used to investigate a wide range of biological phenomena, including the effects of host-microbe interactions on human health and disease, the impact of different cell types on tissue development and homeostasis, and the role of microbial communities in shaping ecosystems. These techniques can also be used to test the efficacy and safety of new drugs or therapies by examining their effects on cells grown in coculture with other relevant cell types.

There are several different ways to establish cocultures, depending on the specific research question and experimental goals. Some common methods include:

1. Mixed cultures: In this approach, two or more cell types are simply mixed together in a culture dish or flask and allowed to grow and interact freely.
2. Cell-layer cultures: Here, one cell type is grown on a porous membrane or other support structure, while the second cell type is grown on top of it, forming a layered coculture.
3. Conditioned media cultures: In this case, one cell type is grown to confluence and its culture medium is collected and then used to grow a second cell type. This allows the second cell type to be exposed to any factors secreted by the first cell type into the medium.
4. Microfluidic cocultures: These involve growing cells in microfabricated channels or chambers, which allow for precise control over the spatial arrangement and flow of nutrients, waste products, and signaling molecules between different cell types.

Overall, coculture techniques provide a powerful tool for studying complex biological systems and gaining insights into the mechanisms that underlie various physiological and pathological processes.

The testis, also known as the testicle, is a male reproductive organ that is part of the endocrine system. It is located in the scrotum, outside of the abdominal cavity. The main function of the testis is to produce sperm and testosterone, the primary male sex hormone.

The testis is composed of many tiny tubules called seminiferous tubules, where sperm are produced. These tubules are surrounded by a network of blood vessels, nerves, and supportive tissues. The sperm then travel through a series of ducts to the epididymis, where they mature and become capable of fertilization.

Testosterone is produced in the Leydig cells, which are located in the interstitial tissue between the seminiferous tubules. Testosterone plays a crucial role in the development and maintenance of male secondary sexual characteristics, such as facial hair, deep voice, and muscle mass. It also supports sperm production and sexual function.

Abnormalities in testicular function can lead to infertility, hormonal imbalances, and other health problems. Regular self-examinations and medical check-ups are recommended for early detection and treatment of any potential issues.

Polycomb Repressive Complex 1 (PRC1) is a protein complex that plays a crucial role in the epigenetic regulation of gene expression, primarily through the process of histone modification. It is associated with the maintenance of gene repression during development and differentiation. PRC1 facilitates the monoubiquitination of histone H2A at lysine 119 (H2AK119ub1), leading to chromatin compaction and transcriptional silencing. This complex is composed of several core subunits, including BMI1, RING1A/B, and one of the six PCGF proteins, which define different PRC1 variants. Dysregulation of PRC1 has been implicated in various human diseases, such as cancers and developmental disorders.

Nuclear reprogramming is a process by which the epigenetic information and gene expression profile of a differentiated cell are altered to resemble those of a pluripotent stem cell. This is typically achieved through the introduction of specific transcription factors, such as Oct4, Sox2, Klf4, and c-Myc (often referred to as the Yamanaka factors), into the differentiated cell's nucleus. These factors work together to reprogram the cell's gene expression profile, leading to the activation of genes that are typically silent in differentiated cells and the repression of genes that are active in differentiated cells.

The result is a cell with many of the characteristics of a pluripotent stem cell, including the ability to differentiate into any cell type found in the body. This process has significant implications for regenerative medicine, as it offers the potential to generate patient-specific stem cells that can be used for tissue repair and replacement. However, nuclear reprogramming is still an inefficient and poorly understood process, and further research is needed to fully realize its potential.

The Wnt signaling pathway is a complex cell communication system that plays a critical role in embryonic development, tissue regeneration, and cancer. It is named after the Wingless (Wg) gene in Drosophila melanogaster and the Int-1 gene in mice, both of which were found to be involved in this pathway.

In essence, the Wnt signaling pathway involves the binding of Wnt proteins to Frizzled receptors on the cell surface, leading to the activation of intracellular signaling cascades. There are three main branches of the Wnt signaling pathway: the canonical (or Wnt/β-catenin) pathway, the noncanonical planar cell polarity (PCP) pathway, and the noncanonical Wnt/calcium pathway.

The canonical Wnt/β-catenin pathway is the most well-studied branch. In the absence of Wnt signaling, cytoplasmic β-catenin is constantly phosphorylated by a destruction complex consisting of Axin, APC, GSK3β, and CK1, leading to its ubiquitination and degradation in the proteasome. When Wnt ligands bind to Frizzled receptors and their coreceptor LRP5/6, Dishevelled is recruited and inhibits the destruction complex, allowing β-catenin to accumulate in the cytoplasm and translocate into the nucleus. In the nucleus, β-catenin interacts with TCF/LEF transcription factors to regulate the expression of target genes involved in cell proliferation, differentiation, and survival.

Dysregulation of the Wnt signaling pathway has been implicated in various human diseases, including cancer, developmental disorders, and degenerative conditions. For example, mutations in components of the canonical Wnt/β-catenin pathway can lead to the accumulation of β-catenin and subsequent activation of oncogenic target genes, contributing to tumorigenesis in various types of cancer.

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 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.

Cell shape refers to the physical form or configuration of a cell, which is determined by the cytoskeleton (the internal framework of the cell) and the extracellular matrix (the external environment surrounding the cell). The shape of a cell can vary widely depending on its type and function. For example, some cells are spherical, such as red blood cells, while others are elongated or irregularly shaped. Changes in cell shape can be indicative of various physiological or pathological processes, including development, differentiation, migration, and disease.

The dental sac, also known as the dental follicle, is a soft tissue structure that surrounds the developing tooth crown during odontogenesis, which is the process of tooth development. It is derived from the ectoderm and mesenchyme of the embryonic oral cavity. The dental sac gives rise to several important structures associated with the tooth, including the periodontal ligament, cementum, and the alveolar bone that surrounds and supports the tooth in the jaw.

The dental sac plays a critical role in tooth development by regulating the mineralization of the tooth crown and providing a protective environment for the developing tooth. It also contains cells called odontoblasts, which are responsible for producing dentin, one of the hard tissues that make up the tooth. Abnormalities in the development or growth of the dental sac can lead to various dental anomalies, such as impacted teeth, dilacerated roots, and other developmental disorders.

Hematopoiesis is the process of forming and developing blood cells. It occurs in the bone marrow and includes the production of red blood cells (erythropoiesis), white blood cells (leukopoiesis), and platelets (thrombopoiesis). This process is regulated by various growth factors, hormones, and cytokines. Hematopoiesis begins early in fetal development and continues throughout a person's life. Disorders of hematopoiesis can result in conditions such as anemia, leukopenia, leukocytosis, thrombocytopenia, or thrombocytosis.

Osteocytes are the most abundant cell type in mature bone tissue. They are star-shaped cells that are located inside the mineralized matrix of bones, with their processes extending into small spaces called lacunae and canaliculi. Osteocytes are derived from osteoblasts, which are bone-forming cells that become trapped within the matrix they produce.

Osteocytes play a crucial role in maintaining bone homeostasis by regulating bone remodeling, sensing mechanical stress, and modulating mineralization. They communicate with each other and with osteoblasts and osteoclasts (bone-resorbing cells) through a network of interconnected processes and via the release of signaling molecules. Osteocytes can also respond to changes in their environment, such as hormonal signals or mechanical loading, by altering their gene expression and releasing factors that regulate bone metabolism.

Dysfunction of osteocytes has been implicated in various bone diseases, including osteoporosis, osteogenesis imperfecta, and Paget's disease of bone.

Neurons, also known as nerve cells or neurocytes, are specialized cells that constitute the basic unit of the nervous system. They are responsible for receiving, processing, and transmitting information and signals within the body. Neurons have three main parts: the dendrites, the cell body (soma), and the axon. The dendrites receive signals from other neurons or sensory receptors, while the axon transmits these signals to other neurons, muscles, or glands. The junction between two neurons is called a synapse, where neurotransmitters are released to transmit the signal across the gap (synaptic cleft) to the next neuron. Neurons vary in size, shape, and structure depending on their function and location within the nervous system.

Neurogenesis is the process by which new neurons (nerve cells) are generated in the brain. It occurs throughout life in certain areas of the brain, such as the hippocampus and subventricular zone, although the rate of neurogenesis decreases with age. Neurogenesis involves the proliferation, differentiation, and integration of new neurons into existing neural circuits. This process plays a crucial role in learning, memory, and recovery from brain injury or disease.

Homeodomain proteins are a group of transcription factors that play crucial roles in the development and differentiation of cells in animals and plants. They are characterized by the presence of a highly conserved DNA-binding domain called the homeodomain, which is typically about 60 amino acids long. The homeodomain consists of three helices, with the third helix responsible for recognizing and binding to specific DNA sequences.

Homeodomain proteins are involved in regulating gene expression during embryonic development, tissue maintenance, and organismal growth. They can act as activators or repressors of transcription, depending on the context and the presence of cofactors. Mutations in homeodomain proteins have been associated with various human diseases, including cancer, congenital abnormalities, and neurological disorders.

Some examples of homeodomain proteins include PAX6, which is essential for eye development, HOX genes, which are involved in body patterning, and NANOG, which plays a role in maintaining pluripotency in stem cells.

Bone Morphogenetic Protein 6 (BMP-6) is a member of the transforming growth factor-beta (TGF-β) superfamily of proteins. It plays crucial roles in bone and cartilage formation, as well as in the regulation of iron metabolism. BMP-6 stimulates the differentiation of mesenchymal stem cells into osteoblasts, which are bone-forming cells, and contributes to the maintenance of bone homeostasis. Additionally, BMP-6 is involved in the process of hepcidin regulation, a hormone that controls iron absorption and recycling in the body. Dysregulation of BMP-6 has been implicated in various diseases, including skeletal disorders and iron metabolism-related conditions.

Epithelial cells are types of cells that cover the outer surfaces of the body, line the inner surfaces of organs and glands, and form the lining of blood vessels and body cavities. They provide a protective barrier against the external environment, regulate the movement of materials between the internal and external environments, and are involved in the sense of touch, temperature, and pain. Epithelial cells can be squamous (flat and thin), cuboidal (square-shaped and of equal height), or columnar (tall and narrow) in shape and are classified based on their location and function.

Notch receptors are a type of transmembrane receptor proteins that play crucial roles in cell-cell communication and regulation of various biological processes, including cell fate determination, differentiation, proliferation, and apoptosis. These receptors are highly conserved across species and are essential for normal development and tissue homeostasis.

The Notch signaling pathway is initiated when the extracellular domain of a Notch receptor on one cell interacts with its ligand (such as Delta or Jagged) on an adjacent cell. This interaction triggers a series of proteolytic cleavage events that release the intracellular domain of the Notch receptor, which then translocates to the nucleus and regulates gene expression by interacting with transcription factors like CSL (CBF1/RBP-Jκ/Su(H)/Lag-1).

There are four known Notch receptors in humans (Notch1-4) that share a similar structure, consisting of an extracellular domain containing multiple epidermal growth factor (EGF)-like repeats, a transmembrane domain, and an intracellular domain. Mutations or dysregulation of the Notch signaling pathway have been implicated in various human diseases, including cancer, cardiovascular disorders, and developmental abnormalities.

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.

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.

Cell survival refers to the ability of a cell to continue living and functioning normally, despite being exposed to potentially harmful conditions or treatments. This can include exposure to toxins, radiation, chemotherapeutic drugs, or other stressors that can damage cells or interfere with their normal processes.

In scientific research, measures of cell survival are often used to evaluate the effectiveness of various therapies or treatments. For example, researchers may expose cells to a particular drug or treatment and then measure the percentage of cells that survive to assess its potential therapeutic value. Similarly, in toxicology studies, measures of cell survival can help to determine the safety of various chemicals or substances.

It's important to note that cell survival is not the same as cell proliferation, which refers to the ability of cells to divide and multiply. While some treatments may promote cell survival, they may also inhibit cell proliferation, making them useful for treating diseases such as cancer. Conversely, other treatments may be designed to specifically target and kill cancer cells, even if it means sacrificing some healthy cells in the process.

Skeletal myoblasts are the precursor cells responsible for the formation and repair of skeletal muscle fibers. They are also known as satellite cells, located in a quiescent state between the basal lamina and sarcolemma of mature muscle fibers. Upon muscle injury or damage, these cells become activated, proliferate, differentiate into myocytes, align with existing muscle fibers, and fuse to form new muscle fibers or repair damaged ones. This process is crucial for postnatal growth, maintenance, and regeneration of skeletal muscles.

Bone marrow transplantation (BMT) is a medical procedure in which damaged or destroyed bone marrow is replaced with healthy bone marrow from a donor. Bone marrow is the spongy tissue inside bones that produces blood cells. The main types of BMT are autologous, allogeneic, and umbilical cord blood transplantation.

In autologous BMT, the patient's own bone marrow is used for the transplant. This type of BMT is often used in patients with lymphoma or multiple myeloma who have undergone high-dose chemotherapy or radiation therapy to destroy their cancerous bone marrow.

In allogeneic BMT, bone marrow from a genetically matched donor is used for the transplant. This type of BMT is often used in patients with leukemia, lymphoma, or other blood disorders who have failed other treatments.

Umbilical cord blood transplantation involves using stem cells from umbilical cord blood as a source of healthy bone marrow. This type of BMT is often used in children and adults who do not have a matched donor for allogeneic BMT.

The process of BMT typically involves several steps, including harvesting the bone marrow or stem cells from the donor, conditioning the patient's body to receive the new bone marrow or stem cells, transplanting the new bone marrow or stem cells into the patient's body, and monitoring the patient for signs of engraftment and complications.

BMT is a complex and potentially risky procedure that requires careful planning, preparation, and follow-up care. However, it can be a life-saving treatment for many patients with blood disorders or cancer.

'Drosophila proteins' refer to the proteins that are expressed in the fruit fly, Drosophila melanogaster. This organism is a widely used model system in genetics, developmental biology, and molecular biology research. The study of Drosophila proteins has contributed significantly to our understanding of various biological processes, including gene regulation, cell signaling, development, and aging.

Some examples of well-studied Drosophila proteins include:

1. HSP70 (Heat Shock Protein 70): A chaperone protein involved in protein folding and protection from stress conditions.
2. TUBULIN: A structural protein that forms microtubules, important for cell division and intracellular transport.
3. ACTIN: A cytoskeletal protein involved in muscle contraction, cell motility, and maintenance of cell shape.
4. BETA-GALACTOSIDASE (LACZ): A reporter protein often used to monitor gene expression patterns in transgenic flies.
5. ENDOGLIN: A protein involved in the development of blood vessels during embryogenesis.
6. P53: A tumor suppressor protein that plays a crucial role in preventing cancer by regulating cell growth and division.
7. JUN-KINASE (JNK): A signaling protein involved in stress response, apoptosis, and developmental processes.
8. DECAPENTAPLEGIC (DPP): A member of the TGF-β (Transforming Growth Factor Beta) superfamily, playing essential roles in embryonic development and tissue homeostasis.

These proteins are often studied using various techniques such as biochemistry, genetics, molecular biology, and structural biology to understand their functions, interactions, and regulation within the cell.

Peripheral Blood Stem Cell Transplantation (PBSCT) is a medical procedure that involves the transplantation of stem cells, which are immature cells found in the bone marrow that can develop into different types of blood cells. In PBSCT, these stem cells are collected from the peripheral blood instead of directly from the bone marrow.

The process begins with mobilization, where a growth factor medication is given to the donor to stimulate the release of stem cells from the bone marrow into the peripheral blood. After several days, the donor's blood is then removed through a procedure called apheresis, where the stem cells are separated and collected while the remaining blood components are returned to the donor.

The collected stem cells are then infused into the recipient's bloodstream, where they migrate to the bone marrow and begin to repopulate, leading to the production of new blood cells. This procedure is often used as a treatment for various malignant and non-malignant disorders, such as leukemia, lymphoma, multiple myeloma, and aplastic anemia.

PBSCT offers several advantages over traditional bone marrow transplantation, including faster engraftment, lower risk of graft failure, and reduced procedure-related morbidity. However, it also has its own set of challenges, such as the potential for increased incidence of chronic graft-versus-host disease (GVHD) and the need for more stringent HLA matching between donor and recipient.

RNA interference (RNAi) is a biological process in which RNA molecules inhibit the expression of specific genes. This process is mediated by small RNA molecules, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), that bind to complementary sequences on messenger RNA (mRNA) molecules, leading to their degradation or translation inhibition.

RNAi plays a crucial role in regulating gene expression and defending against foreign genetic elements, such as viruses and transposons. It has also emerged as an important tool for studying gene function and developing therapeutic strategies for various diseases, including cancer and viral infections.

A clone is a group of cells that are genetically identical to each other because they are derived from a common ancestor cell through processes such as mitosis or asexual reproduction. Therefore, the term "clone cells" refers to a population of cells that are genetic copies of a single parent cell.

In the context of laboratory research, cells can be cloned by isolating a single cell and allowing it to divide in culture, creating a population of genetically identical cells. This is useful for studying the behavior and characteristics of individual cell types, as well as for generating large quantities of cells for use in experiments.

It's important to note that while clone cells are genetically identical, they may still exhibit differences in their phenotype (physical traits) due to epigenetic factors or environmental influences.

Cell movement, also known as cell motility, refers to the ability of cells to move independently and change their location within tissue or inside the body. This process is essential for various biological functions, including embryonic development, wound healing, immune responses, and cancer metastasis.

There are several types of cell movement, including:

1. **Crawling or mesenchymal migration:** Cells move by extending and retracting protrusions called pseudopodia or filopodia, which contain actin filaments. This type of movement is common in fibroblasts, immune cells, and cancer cells during tissue invasion and metastasis.
2. **Amoeboid migration:** Cells move by changing their shape and squeezing through tight spaces without forming protrusions. This type of movement is often observed in white blood cells (leukocytes) as they migrate through the body to fight infections.
3. **Pseudopodial extension:** Cells extend pseudopodia, which are temporary cytoplasmic projections containing actin filaments. These protrusions help the cell explore its environment and move forward.
4. **Bacterial flagellar motion:** Bacteria use a whip-like structure called a flagellum to propel themselves through their environment. The rotation of the flagellum is driven by a molecular motor in the bacterial cell membrane.
5. **Ciliary and ependymal movement:** Ciliated cells, such as those lining the respiratory tract and fallopian tubes, have hair-like structures called cilia that beat in coordinated waves to move fluids or mucus across the cell surface.

Cell movement is regulated by a complex interplay of signaling pathways, cytoskeletal rearrangements, and adhesion molecules, which enable cells to respond to environmental cues and navigate through tissues.

Totipotent stem cells are a type of stem cell that have the greatest developmental potential and can differentiate into any cell type in the body, including extra-embryonic tissues such as the placenta. These stem cells are derived from the fertilized egg (zygote) and are capable of forming a complete organism. As development progresses, totipotent stem cells become more restricted in their differentiation potential, giving rise to pluripotent stem cells, which can differentiate into any cell type in the body but not extra-embryonic tissues. Totipotent stem cells are rarely found in adults and are primarily studied in the context of embryonic development and regenerative medicine.

"Cell count" is a medical term that refers to the process of determining the number of cells present in a given volume or sample of fluid or tissue. This can be done through various laboratory methods, such as counting individual cells under a microscope using a specialized grid called a hemocytometer, or using automated cell counters that use light scattering and electrical impedance techniques to count and classify different types of cells.

Cell counts are used in a variety of medical contexts, including hematology (the study of blood and blood-forming tissues), microbiology (the study of microscopic organisms), and pathology (the study of diseases and their causes). For example, a complete blood count (CBC) is a routine laboratory test that includes a white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin level, hematocrit value, and platelet count. Abnormal cell counts can indicate the presence of various medical conditions, such as infections, anemia, or leukemia.

Bone marrow is the spongy tissue found inside certain bones in the body, such as the hips, thighs, and vertebrae. It is responsible for producing blood-forming cells, including red blood cells, white blood cells, and platelets. There are two types of bone marrow: red marrow, which is involved in blood cell production, and yellow marrow, which contains fatty tissue.

Red bone marrow contains hematopoietic stem cells, which can differentiate into various types of blood cells. These stem cells continuously divide and mature to produce new blood cells that are released into the circulation. Red blood cells carry oxygen throughout the body, white blood cells help fight infections, and platelets play a crucial role in blood clotting.

Bone marrow also serves as a site for immune cell development and maturation. It contains various types of immune cells, such as lymphocytes, macrophages, and dendritic cells, which help protect the body against infections and diseases.

Abnormalities in bone marrow function can lead to several medical conditions, including anemia, leukopenia, thrombocytopenia, and various types of cancer, such as leukemia and multiple myeloma. Bone marrow aspiration and biopsy are common diagnostic procedures used to evaluate bone marrow health and function.

Melanocytes are specialized cells that produce, store, and transport melanin, the pigment responsible for coloring of the skin, hair, and eyes. They are located in the bottom layer of the epidermis (the outermost layer of the skin) and can also be found in the inner ear and the eye's retina. Melanocytes contain organelles called melanosomes, which produce and store melanin.

Melanin comes in two types: eumelanin (black or brown) and pheomelanin (red or yellow). The amount and type of melanin produced by melanocytes determine the color of a person's skin, hair, and eyes. Exposure to UV radiation from sunlight increases melanin production as a protective response, leading to skin tanning.

Melanocyte dysfunction or abnormalities can lead to various medical conditions, such as albinism (lack of melanin production), melasma (excessive pigmentation), and melanoma (cancerous growth of melanocytes).

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.

Homologous transplantation is a type of transplant surgery where organs or tissues are transferred between two genetically non-identical individuals of the same species. The term "homologous" refers to the similarity in structure and function of the donated organ or tissue to the recipient's own organ or tissue.

For example, a heart transplant from one human to another is an example of homologous transplantation because both organs are hearts and perform the same function. Similarly, a liver transplant, kidney transplant, lung transplant, and other types of organ transplants between individuals of the same species are also considered homologous transplantations.

Homologous transplantation is in contrast to heterologous or xenogeneic transplantation, where organs or tissues are transferred from one species to another, such as a pig heart transplanted into a human. Homologous transplantation is more commonly performed than heterologous transplantation due to the increased risk of rejection and other complications associated with xenogeneic transplants.

In medical and embryological terms, the mesoderm is one of the three primary germ layers in the very early stages of embryonic development. It forms between the ectoderm and endoderm during gastrulation, and it gives rise to a wide variety of cell types, tissues, and organs in the developing embryo.

The mesoderm contributes to the formation of structures such as:

1. The connective tissues (including tendons, ligaments, and most of the bones)
2. Muscular system (skeletal, smooth, and cardiac muscles)
3. Circulatory system (heart, blood vessels, and blood cells)
4. Excretory system (kidneys and associated structures)
5. Reproductive system (gonads, including ovaries and testes)
6. Dermis of the skin
7. Parts of the eye and inner ear
8. Several organs in the urogenital system

Dysfunctions or abnormalities in mesoderm development can lead to various congenital disorders and birth defects, highlighting its importance during embryogenesis.

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.

Oligonucleotide Array Sequence Analysis is a type of microarray analysis that allows for the simultaneous measurement of the expression levels of thousands of genes in a single sample. In this technique, oligonucleotides (short DNA sequences) are attached to a solid support, such as a glass slide, in a specific pattern. These oligonucleotides are designed to be complementary to specific target mRNA sequences from the sample being analyzed.

During the analysis, labeled RNA or cDNA from the sample is hybridized to the oligonucleotide array. The level of hybridization is then measured and used to determine the relative abundance of each target sequence in the sample. This information can be used to identify differences in gene expression between samples, which can help researchers understand the underlying biological processes involved in various diseases or developmental stages.

It's important to note that this technique requires specialized equipment and bioinformatics tools for data analysis, as well as careful experimental design and validation to ensure accurate and reproducible results.

Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.

Muscle development, also known as muscle hypertrophy, refers to the increase in size and mass of the muscles through a process called myofiber growth. This is primarily achieved through resistance or strength training exercises that cause micro-tears in the muscle fibers, leading to an inflammatory response and the release of hormones that promote muscle growth. As the muscles repair themselves, they become larger and stronger than before. Proper nutrition, including adequate protein intake, and rest are also essential components of muscle development.

It is important to note that while muscle development can lead to an increase in strength and muscular endurance, it does not necessarily result in improved athletic performance or overall fitness. A well-rounded exercise program that includes cardiovascular activity, flexibility training, and resistance exercises is recommended for optimal health and fitness outcomes.

CD (cluster of differentiation) antigens are cell-surface proteins that are expressed on leukocytes (white blood cells) and can be used to identify and distinguish different subsets of these cells. They are important markers in the field of immunology and hematology, and are commonly used to diagnose and monitor various diseases, including cancer, autoimmune disorders, and infectious diseases.

CD antigens are designated by numbers, such as CD4, CD8, CD19, etc., which refer to specific proteins found on the surface of different types of leukocytes. For example, CD4 is a protein found on the surface of helper T cells, while CD8 is found on cytotoxic T cells.

CD antigens can be used as targets for immunotherapy, such as monoclonal antibody therapy, in which antibodies are designed to bind to specific CD antigens and trigger an immune response against cancer cells or infected cells. They can also be used as markers to monitor the effectiveness of treatments and to detect minimal residual disease (MRD) after treatment.

It's important to note that not all CD antigens are exclusive to leukocytes, some can be found on other cell types as well, and their expression can vary depending on the activation state or differentiation stage of the cells.

Bromodeoxyuridine (BrdU) is a synthetic thymidine analog that can be incorporated into DNA during cell replication. It is often used in research and medical settings as a marker for cell proliferation or as a tool to investigate DNA synthesis and repair. When cells are labeled with BrdU and then examined using immunofluorescence or other detection techniques, the presence of BrdU can indicate which cells have recently divided or are actively synthesizing DNA.

In medical contexts, BrdU has been used in cancer research to study tumor growth and response to treatment. It has also been explored as a potential therapeutic agent for certain conditions, such as neurodegenerative diseases, where promoting cell proliferation and replacement of damaged cells may be beneficial. However, its use as a therapeutic agent is still experimental and requires further investigation.

Lamin Type A, also known as LMNA, is a gene that provides instructions for making proteins called lamins. These proteins are part of the nuclear lamina, a network of fibers that lies just inside the nuclear envelope, which is the membrane that surrounds the cell's nucleus. The nuclear lamina helps maintain the shape and stability of the nucleus and plays a role in regulating gene expression and DNA replication.

Mutations in the LMNA gene can lead to various diseases collectively known as laminopathies, which affect different tissues and organs in the body. These conditions include Emery-Dreifuss muscular dystrophy, limb-girdle muscular dystrophy, dilated cardiomyopathy with conduction system disease, and a type of premature aging disorder called Hutchinson-Gilford progeria syndrome. The specific symptoms and severity of these disorders depend on the particular LMNA mutation and the tissues affected.

The corneal epithelium is the outermost layer of the cornea, which is the clear, dome-shaped surface at the front of the eye. It is a stratified squamous epithelium, consisting of several layers of flat, scale-like cells that are tightly packed together. The corneal epithelium serves as a barrier to protect the eye from microorganisms, dust, and other foreign particles. It also provides a smooth surface for the refraction of light, contributes to the maintenance of corneal transparency, and plays a role in the eye's sensitivity to touch and pain. The corneal epithelium is constantly being renewed through the process of cell division and shedding, with new cells produced by stem cells located at the limbus, the border between the cornea and the conjunctiva.

Beta-catenin is a protein that plays a crucial role in gene transcription and cell-cell adhesion. It is a key component of the Wnt signaling pathway, which regulates various processes such as cell proliferation, differentiation, and migration during embryonic development and tissue homeostasis in adults.

In the absence of Wnt signals, beta-catenin forms a complex with other proteins, including adenomatous polyposis coli (APC) and axin, which targets it for degradation by the proteasome. When Wnt ligands bind to their receptors, this complex is disrupted, allowing beta-catenin to accumulate in the cytoplasm and translocate to the nucleus. In the nucleus, beta-catenin interacts with T cell factor/lymphoid enhancer-binding factor (TCF/LEF) transcription factors to activate the transcription of target genes involved in cell fate determination, survival, and proliferation.

Mutations in the genes encoding components of the Wnt signaling pathway, including beta-catenin, have been implicated in various human diseases, such as cancer, developmental disorders, and degenerative conditions.

'Drosophila melanogaster' is the scientific name for a species of fruit fly that is commonly used as a model organism in various fields of biological research, including genetics, developmental biology, and evolutionary biology. Its small size, short generation time, large number of offspring, and ease of cultivation make it an ideal subject for laboratory studies. The fruit fly's genome has been fully sequenced, and many of its genes have counterparts in the human genome, which facilitates the understanding of genetic mechanisms and their role in human health and disease.

Here is a brief medical definition:

Drosophila melanogaster (droh-suh-fih-luh meh-lon-guh-ster): A species of fruit fly used extensively as a model organism in genetic, developmental, and evolutionary research. Its genome has been sequenced, revealing many genes with human counterparts, making it valuable for understanding genetic mechanisms and their role in human health and disease.

Bone regeneration is the biological process of new bone formation that occurs after an injury or removal of a portion of bone. This complex process involves several stages, including inflammation, migration and proliferation of cells, matrix deposition, and mineralization, leading to the restoration of the bone's structure and function.

The main cells involved in bone regeneration are osteoblasts, which produce new bone matrix, and osteoclasts, which resorb damaged or old bone tissue. The process is tightly regulated by various growth factors, hormones, and signaling molecules that promote the recruitment, differentiation, and activity of these cells.

Bone regeneration can occur naturally in response to injury or surgical intervention, such as fracture repair or dental implant placement. However, in some cases, bone regeneration may be impaired due to factors such as age, disease, or trauma, leading to delayed healing or non-union of the bone. In these situations, various strategies and techniques, including the use of bone grafts, scaffolds, and growth factors, can be employed to enhance and support the bone regeneration process.

Biological metamorphosis is a complex process of transformation that certain organisms undergo during their development from embryo to adult. This process involves profound changes in form, function, and structure of the organism, often including modifications of various body parts, reorganization of internal organs, and changes in physiology.

In metamorphosis, a larval or juvenile form of an animal is significantly different from its adult form, both morphologically and behaviorally. This phenomenon is particularly common in insects, amphibians, and some fish and crustaceans. The most well-known examples include the transformation of a caterpillar into a butterfly or a tadpole into a frog.

The mechanisms that drive metamorphosis are regulated by hormonal signals and genetic programs. In many cases, metamorphosis is triggered by environmental factors such as temperature, moisture, or food availability, which interact with the organism's internal developmental cues to initiate the transformation. The process of metamorphosis allows these organisms to exploit different ecological niches at different stages of their lives and contributes to their evolutionary success.

Wound healing is a complex and dynamic process that occurs after tissue injury, aiming to restore the integrity and functionality of the damaged tissue. It involves a series of overlapping phases: hemostasis, inflammation, proliferation, and remodeling.

1. Hemostasis: This initial phase begins immediately after injury and involves the activation of the coagulation cascade to form a clot, which stabilizes the wound and prevents excessive blood loss.
2. Inflammation: Activated inflammatory cells, such as neutrophils and monocytes/macrophages, infiltrate the wound site to eliminate pathogens, remove debris, and release growth factors that promote healing. This phase typically lasts for 2-5 days post-injury.
3. Proliferation: In this phase, various cell types, including fibroblasts, endothelial cells, and keratinocytes, proliferate and migrate to the wound site to synthesize extracellular matrix (ECM) components, form new blood vessels (angiogenesis), and re-epithelialize the wounded area. This phase can last up to several weeks depending on the size and severity of the wound.
4. Remodeling: The final phase of wound healing involves the maturation and realignment of collagen fibers, leading to the restoration of tensile strength in the healed tissue. This process can continue for months to years after injury, although the tissue may never fully regain its original structure and function.

It is important to note that wound healing can be compromised by several factors, including age, nutrition, comorbidities (e.g., diabetes, vascular disease), and infection, which can result in delayed healing or non-healing chronic wounds.

Muscle cells, also known as muscle fibers, are specialized cells that have the ability to contract and generate force, allowing for movement of the body and various internal organ functions. There are three main types of muscle tissue: skeletal, cardiac, and smooth.

Skeletal muscle cells are voluntary striated muscles attached to bones, enabling body movements and posture. They are multinucleated, with numerous nuclei located at the periphery of the cell. These cells are often called muscle fibers and can be quite large, extending the entire length of the muscle.

Cardiac muscle cells form the contractile tissue of the heart. They are also striated but have a single nucleus per cell and are interconnected by specialized junctions called intercalated discs, which help coordinate contraction throughout the heart.

Smooth muscle cells are found in various internal organs such as the digestive, respiratory, and urinary tracts, blood vessels, and the reproductive system. They are involuntary, non-striated muscles that control the internal organ functions. Smooth muscle cells have a single nucleus per cell and can either be spindle-shaped or stellate (star-shaped).

In summary, muscle cells are specialized contractile cells responsible for movement and various internal organ functions in the human body. They can be categorized into three types: skeletal, cardiac, and smooth, based on their structure, location, and function.

Cell fusion is the process by which two or more cells combine to form a single cell with a single nucleus, containing the genetic material from all of the original cells. This can occur naturally in certain biological processes, such as fertilization (when a sperm and egg cell fuse to form a zygote), muscle development (where multiple muscle precursor cells fuse together to create multinucleated muscle fibers), and during the formation of bone (where osteoclasts, the cells responsible for breaking down bone tissue, are multinucleated).

Cell fusion can also be induced artificially in laboratory settings through various methods, including chemical treatments, electrical stimulation, or viral vectors. Induced cell fusion is often used in research to create hybrid cells with unique properties, such as cybrid cells (cytoplasmic hybrids) and heterokaryons (nuclear hybrids). These hybrid cells can help scientists study various aspects of cell biology, genetics, and disease mechanisms.

In summary, cell fusion is the merging of two or more cells into one, resulting in a single cell with combined genetic material. This process occurs naturally during certain biological processes and can be induced artificially for research purposes.

An animal model in medicine refers to the use of non-human animals in experiments to understand, predict, and test responses and effects of various biological and chemical interactions that may also occur in humans. These models are used when studying complex systems or processes that cannot be easily replicated or studied in human subjects, such as genetic manipulation or exposure to harmful substances. The choice of animal model depends on the specific research question being asked and the similarities between the animal's and human's biological and physiological responses. Examples of commonly used animal models include mice, rats, rabbits, guinea pigs, and non-human primates.

Aging is a complex, progressive and inevitable process of bodily changes over time, characterized by the accumulation of cellular damage and degenerative changes that eventually lead to increased vulnerability to disease and death. It involves various biological, genetic, environmental, and lifestyle factors that contribute to the decline in physical and mental functions. The medical field studies aging through the discipline of gerontology, which aims to understand the underlying mechanisms of aging and develop interventions to promote healthy aging and extend the human healthspan.

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.

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.

Neoplastic cell transformation is a process in which a normal cell undergoes genetic alterations that cause it to become cancerous or malignant. This process involves changes in the cell's DNA that result in uncontrolled cell growth and division, loss of contact inhibition, and the ability to invade surrounding tissues and metastasize (spread) to other parts of the body.

Neoplastic transformation can occur as a result of various factors, including genetic mutations, exposure to carcinogens, viral infections, chronic inflammation, and aging. These changes can lead to the activation of oncogenes or the inactivation of tumor suppressor genes, which regulate cell growth and division.

The transformation of normal cells into cancerous cells is a complex and multi-step process that involves multiple genetic and epigenetic alterations. It is characterized by several hallmarks, including sustained proliferative signaling, evasion of growth suppressors, resistance to cell death, enabling replicative immortality, induction of angiogenesis, activation of invasion and metastasis, reprogramming of energy metabolism, and evading immune destruction.

Neoplastic cell transformation is a fundamental concept in cancer biology and is critical for understanding the molecular mechanisms underlying cancer development and progression. It also has important implications for cancer diagnosis, prognosis, and treatment, as identifying the specific genetic alterations that underlie neoplastic transformation can help guide targeted therapies and personalized medicine approaches.

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.

SCID mice is an acronym for Severe Combined Immunodeficiency mice. These are genetically modified mice that lack a functional immune system due to the mutation or knockout of several key genes required for immunity. This makes them ideal for studying the human immune system, infectious diseases, and cancer, as well as testing new therapies and treatments in a controlled environment without the risk of interference from the mouse's own immune system. SCID mice are often used in xenotransplantation studies, where human cells or tissues are transplanted into the mouse to study their behavior and interactions with the human immune system.

Neoplasms are abnormal growths of cells or tissues in the body that serve no physiological function. They can be benign (non-cancerous) or malignant (cancerous). Benign neoplasms are typically slow growing and do not spread to other parts of the body, while malignant neoplasms are aggressive, invasive, and can metastasize to distant sites.

Neoplasms occur when there is a dysregulation in the normal process of cell division and differentiation, leading to uncontrolled growth and accumulation of cells. This can result from genetic mutations or other factors such as viral infections, environmental exposures, or hormonal imbalances.

Neoplasms can develop in any organ or tissue of the body and can cause various symptoms depending on their size, location, and type. Treatment options for neoplasms include surgery, radiation therapy, chemotherapy, immunotherapy, and targeted therapy, among others.

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.

Adipocytes are specialized cells that comprise adipose tissue, also known as fat tissue. They are responsible for storing energy in the form of lipids, particularly triglycerides, and releasing energy when needed through a process called lipolysis. There are two main types of adipocytes: white adipocytes and brown adipocytes. White adipocytes primarily store energy, while brown adipocytes dissipate energy as heat through the action of uncoupling protein 1 (UCP1).

In addition to their role in energy metabolism, adipocytes also secrete various hormones and signaling molecules that contribute to whole-body homeostasis. These include leptin, adiponectin, resistin, and inflammatory cytokines. Dysregulation of adipocyte function has been implicated in the development of obesity, insulin resistance, type 2 diabetes, and cardiovascular disease.

Gene knockdown techniques are methods used to reduce the expression or function of specific genes in order to study their role in biological processes. These techniques typically involve the use of small RNA molecules, such as siRNAs (small interfering RNAs) or shRNAs (short hairpin RNAs), which bind to and promote the degradation of complementary mRNA transcripts. This results in a decrease in the production of the protein encoded by the targeted gene.

Gene knockdown techniques are often used as an alternative to traditional gene knockout methods, which involve completely removing or disrupting the function of a gene. Knockdown techniques allow for more subtle and reversible manipulation of gene expression, making them useful for studying genes that are essential for cell survival or have redundant functions.

These techniques are widely used in molecular biology research to investigate gene function, genetic interactions, and disease mechanisms. However, it is important to note that gene knockdown can have off-target effects and may not completely eliminate the expression of the targeted gene, so results should be interpreted with caution.

Fetal blood refers to the blood circulating in a fetus during pregnancy. It is essential for the growth and development of the fetus, as it carries oxygen and nutrients from the placenta to the developing tissues and organs. Fetal blood also removes waste products, such as carbon dioxide, from the fetal tissues and transports them to the placenta for elimination.

Fetal blood has several unique characteristics that distinguish it from adult blood. For example, fetal hemoglobin (HbF) is the primary type of hemoglobin found in fetal blood, whereas adults primarily have adult hemoglobin (HbA). Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, which allows it to more efficiently extract oxygen from the maternal blood in the placenta.

Additionally, fetal blood contains a higher proportion of reticulocytes (immature red blood cells) and nucleated red blood cells compared to adult blood. These differences reflect the high turnover rate of red blood cells in the developing fetus and the need for rapid growth and development.

Examination of fetal blood can provide important information about the health and well-being of the fetus during pregnancy. For example, fetal blood sampling (also known as cordocentesis or percutaneous umbilical blood sampling) can be used to diagnose genetic disorders, infections, and other conditions that may affect fetal development. However, this procedure carries risks, including preterm labor, infection, and fetal loss, and is typically only performed when there is a significant risk of fetal compromise or when other diagnostic tests have been inconclusive.

'Staining and labeling' are techniques commonly used in pathology, histology, cytology, and molecular biology to highlight or identify specific components or structures within tissues, cells, or molecules. These methods enable researchers and medical professionals to visualize and analyze the distribution, localization, and interaction of biological entities, contributing to a better understanding of diseases, cellular processes, and potential therapeutic targets.

Medical definitions for 'staining' and 'labeling' are as follows:

1. Staining: A process that involves applying dyes or stains to tissues, cells, or molecules to enhance their contrast and reveal specific structures or components. Stains can be categorized into basic stains (which highlight acidic structures) and acidic stains (which highlight basic structures). Common staining techniques include Hematoxylin and Eosin (H&E), which differentiates cell nuclei from the surrounding cytoplasm and extracellular matrix; special stains, such as PAS (Periodic Acid-Schiff) for carbohydrates or Masson's trichrome for collagen fibers; and immunostains, which use antibodies to target specific proteins.
2. Labeling: A process that involves attaching a detectable marker or tag to a molecule of interest, allowing its identification, quantification, or tracking within a biological system. Labels can be direct, where the marker is directly conjugated to the targeting molecule, or indirect, where an intermediate linker molecule is used to attach the label to the target. Common labeling techniques include fluorescent labels (such as FITC, TRITC, or Alexa Fluor), enzymatic labels (such as horseradish peroxidase or alkaline phosphatase), and radioactive labels (such as ³²P or ¹⁴C). Labeling is often used in conjunction with staining techniques to enhance the specificity and sensitivity of detection.

Together, staining and labeling provide valuable tools for medical research, diagnostics, and therapeutic development, offering insights into cellular and molecular processes that underlie health and disease.

Repressor proteins are a type of regulatory protein in molecular biology that suppress the transcription of specific genes into messenger RNA (mRNA) by binding to DNA. They function as part of gene regulation processes, often working in conjunction with an operator region and a promoter region within the DNA molecule. Repressor proteins can be activated or deactivated by various signals, allowing for precise control over gene expression in response to changing cellular conditions.

There are two main types of repressor proteins:

1. DNA-binding repressors: These directly bind to specific DNA sequences (operator regions) near the target gene and prevent RNA polymerase from transcribing the gene into mRNA.
2. Allosteric repressors: These bind to effector molecules, which then cause a conformational change in the repressor protein, enabling it to bind to DNA and inhibit transcription.

Repressor proteins play crucial roles in various biological processes, such as development, metabolism, and stress response, by controlling gene expression patterns in cells.

Hedgehog proteins are a group of signaling molecules that play crucial roles in the development and regulation of various biological processes in animals. They are named after the hedgehog mutant fruit flies, which have spiky bristles due to defects in this pathway. These proteins are involved in cell growth, differentiation, and tissue regeneration. They exert their effects by binding to specific receptors on the surface of target cells, leading to a cascade of intracellular signaling events that ultimately influence gene expression and cell behavior.

There are three main types of Hedgehog proteins in mammals: Sonic hedgehog (Shh), Indian hedgehog (Ihh), and Desert hedgehog (Dhh). These protecules undergo post-translational modifications, including cleavage and lipid modification, which are essential for their activity. Dysregulation of Hedgehog signaling has been implicated in various diseases, including cancer, developmental abnormalities, and degenerative disorders.

G-protein-coupled receptors (GPCRs) are a family of membrane receptors that play an essential role in cellular signaling and communication. These receptors possess seven transmembrane domains, forming a structure that spans the lipid bilayer of the cell membrane. They are called "G-protein-coupled" because they interact with heterotrimeric G proteins upon activation, which in turn modulate various downstream signaling pathways.

When an extracellular ligand binds to a GPCR, it causes a conformational change in the receptor's structure, leading to the exchange of guanosine diphosphate (GDP) for guanosine triphosphate (GTP) on the associated G protein's α subunit. This exchange triggers the dissociation of the G protein into its α and βγ subunits, which then interact with various effector proteins to elicit cellular responses.

There are four main families of GPCRs, classified based on their sequence similarities and downstream signaling pathways:

1. Gq-coupled receptors: These receptors activate phospholipase C (PLC), which leads to the production of inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 induces calcium release from intracellular stores, while DAG activates protein kinase C (PKC).
2. Gs-coupled receptors: These receptors activate adenylyl cyclase, which increases the production of cyclic adenosine monophosphate (cAMP) and subsequently activates protein kinase A (PKA).
3. Gi/o-coupled receptors: These receptors inhibit adenylyl cyclase, reducing cAMP levels and modulating PKA activity. Additionally, they can activate ion channels or regulate other signaling pathways through the βγ subunits.
4. G12/13-coupled receptors: These receptors primarily activate RhoGEFs, which in turn activate RhoA and modulate cytoskeletal organization and cellular motility.

GPCRs are involved in various physiological processes, including neurotransmission, hormone signaling, immune response, and sensory perception. Dysregulation of GPCR function has been implicated in numerous diseases, making them attractive targets for drug development.

Proto-oncogene proteins c-kit, also known as CD117 or stem cell factor receptor, are transmembrane receptor tyrosine kinases that play crucial roles in various biological processes, including cell survival, proliferation, differentiation, and migration. They are encoded by the c-KIT gene located on human chromosome 4q12.

These proteins consist of an extracellular ligand-binding domain, a transmembrane domain, and an intracellular tyrosine kinase domain. The binding of their ligand, stem cell factor (SCF), leads to receptor dimerization, autophosphorylation, and activation of several downstream signaling pathways such as PI3K/AKT, MAPK/ERK, and JAK/STAT.

Abnormal activation or mutation of c-kit proto-oncogene proteins has been implicated in the development and progression of various malignancies, including gastrointestinal stromal tumors (GISTs), acute myeloid leukemia (AML), mast cell diseases, and melanoma. Targeted therapies against c-kit, such as imatinib mesylate (Gleevec), have shown promising results in the treatment of these malignancies.

The neural crest is a transient, multipotent embryonic cell population that originates from the ectoderm (outermost layer) of the developing neural tube (precursor to the central nervous system). These cells undergo an epithelial-to-mesenchymal transition and migrate throughout the embryo, giving rise to a diverse array of cell types and structures.

Neural crest cells differentiate into various tissues, including:

1. Peripheral nervous system (PNS) components: sensory neurons, sympathetic and parasympathetic ganglia, and glial cells (e.g., Schwann cells).
2. Facial bones and cartilage, as well as connective tissue of the skull.
3. Melanocytes, which are pigment-producing cells in the skin.
4. Smooth muscle cells in major blood vessels, heart, gastrointestinal tract, and other organs.
5. Secretory cells in endocrine glands (e.g., chromaffin cells of the adrenal medulla).
6. Parts of the eye, such as the cornea and iris stroma.
7. Dental tissues, including dentin, cementum, and dental pulp.

Due to their wide-ranging contributions to various tissues and organs, neural crest cells play a crucial role in embryonic development and organogenesis. Abnormalities in neural crest cell migration or differentiation can lead to several congenital disorders, such as neurocristopathies.

Cord blood stem cell transplantation is a medical procedure that involves the infusion of stem cells derived from the umbilical cord blood into a patient. These stem cells, specifically hematopoietic stem cells, have the ability to differentiate into various types of blood cells, including red and white blood cells and platelets.

Cord blood stem cell transplantation is often used as a treatment for patients with various malignant and non-malignant disorders, such as leukemia, lymphoma, sickle cell disease, and metabolic disorders. The procedure involves collecting cord blood from the umbilical cord and placenta after the birth of a baby, processing and testing it for compatibility with the recipient's immune system, and then infusing it into the patient through a vein in a process similar to a blood transfusion.

The advantages of using cord blood stem cells include their availability, low risk of transmission of infectious diseases, and reduced risk of graft-versus-host disease compared to other sources of hematopoietic stem cells, such as bone marrow or peripheral blood. However, the number of stem cells in a cord blood unit is generally lower than that found in bone marrow or peripheral blood, which can limit its use in some patients, particularly adults.

Overall, cord blood stem cell transplantation is an important and promising area of regenerative medicine, offering hope for patients with a wide range of disorders.

Genetic therapy, also known as gene therapy, is a medical intervention that involves the use of genetic material, such as DNA or RNA, to treat or prevent diseases. It works by introducing functional genes into cells to replace missing or faulty ones caused by genetic disorders or mutations. The introduced gene is incorporated into the recipient's genome, allowing for the production of a therapeutic protein that can help manage the disease symptoms or even cure the condition.

There are several approaches to genetic therapy, including:

1. Replacing a faulty gene with a healthy one
2. Inactivating or "silencing" a dysfunctional gene causing a disease
3. Introducing a new gene into the body to help fight off a disease, such as cancer

Genetic therapy holds great promise for treating various genetic disorders, including cystic fibrosis, muscular dystrophy, hemophilia, and certain types of cancer. However, it is still an evolving field with many challenges, such as efficient gene delivery, potential immune responses, and ensuring the safety and long-term effectiveness of the therapy.

Thrombospondins (TSPs) are a family of multifunctional glycoproteins that are involved in various biological processes, including cell adhesion, migration, proliferation, differentiation, and angiogenesis. They were initially identified as calcium-binding proteins that are secreted by platelets during blood clotting (thrombosis), hence the name thrombospondin.

There are five members in the TSP family, designated as TSP-1 to TSP-5, and they share a common structure consisting of several domains, including an N-terminal domain, a series of type 1 repeats, a type 2 (von Willebrand factor C) repeat, a type 3 repeat, and a C-terminal domain.

TSP-1 and TSP-2 are secreted proteins that have been extensively studied for their roles in the regulation of angiogenesis, the process of new blood vessel formation. They bind to various extracellular matrix components, growth factors, and cell surface receptors, and can either promote or inhibit angiogenesis depending on the context.

TSP-3 to TSP-5 are expressed in a variety of tissues and play roles in cell adhesion, migration, and differentiation. They have been implicated in various pathological conditions, including cancer, fibrosis, and neurodegenerative diseases.

Overall, thrombospondins are important regulators of extracellular matrix dynamics and cell-matrix interactions, and their dysregulation has been associated with a variety of diseases.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

The extracellular matrix (ECM) is a complex network of biomolecules that provides structural and biochemical support to cells in tissues and organs. It is composed of various proteins, glycoproteins, and polysaccharides, such as collagens, elastin, fibronectin, laminin, and proteoglycans. The ECM plays crucial roles in maintaining tissue architecture, regulating cell behavior, and facilitating communication between cells. It provides a scaffold for cell attachment, migration, and differentiation, and helps to maintain the structural integrity of tissues by resisting mechanical stresses. Additionally, the ECM contains various growth factors, cytokines, and chemokines that can influence cellular processes such as proliferation, survival, and differentiation. Overall, the extracellular matrix is essential for the normal functioning of tissues and organs, and its dysregulation can contribute to various pathological conditions, including fibrosis, cancer, and degenerative diseases.

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.

Intercellular signaling peptides and proteins are molecules that mediate communication and interaction between different cells in living organisms. They play crucial roles in various biological processes, including cell growth, differentiation, migration, and apoptosis (programmed cell death). These signals can be released into the extracellular space, where they bind to specific receptors on the target cell's surface, triggering intracellular signaling cascades that ultimately lead to a response.

Peptides are short chains of amino acids, while proteins are larger molecules made up of one or more polypeptide chains. Both can function as intercellular signaling molecules by acting as ligands for cell surface receptors or by being cleaved from larger precursor proteins and released into the extracellular space. Examples of intercellular signaling peptides and proteins include growth factors, cytokines, chemokines, hormones, neurotransmitters, and their respective receptors.

These molecules contribute to maintaining homeostasis within an organism by coordinating cellular activities across tissues and organs. Dysregulation of intercellular signaling pathways has been implicated in various diseases, such as cancer, autoimmune disorders, and neurodegenerative conditions. Therefore, understanding the mechanisms underlying intercellular signaling is essential for developing targeted therapies to treat these disorders.

Genetically modified animals (GMAs) are those whose genetic makeup has been altered using biotechnological techniques. This is typically done by introducing one or more genes from another species into the animal's genome, resulting in a new trait or characteristic that does not naturally occur in that species. The introduced gene is often referred to as a transgene.

The process of creating GMAs involves several steps:

1. Isolation: The desired gene is isolated from the DNA of another organism.
2. Transfer: The isolated gene is transferred into the target animal's cells, usually using a vector such as a virus or bacterium.
3. Integration: The transgene integrates into the animal's chromosome, becoming a permanent part of its genetic makeup.
4. Selection: The modified cells are allowed to multiply, and those that contain the transgene are selected for further growth and development.
5. Breeding: The genetically modified individuals are bred to produce offspring that carry the desired trait.

GMAs have various applications in research, agriculture, and medicine. In research, they can serve as models for studying human diseases or testing new therapies. In agriculture, GMAs can be developed to exhibit enhanced growth rates, improved disease resistance, or increased nutritional value. In medicine, GMAs may be used to produce pharmaceuticals or other therapeutic agents within their bodies.

Examples of genetically modified animals include mice with added genes for specific proteins that make them useful models for studying human diseases, goats that produce a human protein in their milk to treat hemophilia, and pigs with enhanced resistance to certain viruses that could potentially be used as organ donors for humans.

It is important to note that the use of genetically modified animals raises ethical concerns related to animal welfare, environmental impact, and potential risks to human health. These issues must be carefully considered and addressed when developing and implementing GMA technologies.

"Drosophila" is a genus of small flies, also known as fruit flies. The most common species used in scientific research is "Drosophila melanogaster," which has been a valuable model organism for many areas of biological and medical research, including genetics, developmental biology, neurobiology, and aging.

The use of Drosophila as a model organism has led to numerous important discoveries in genetics and molecular biology, such as the identification of genes that are associated with human diseases like cancer, Parkinson's disease, and obesity. The short reproductive cycle, large number of offspring, and ease of genetic manipulation make Drosophila a powerful tool for studying complex biological processes.

Organ specificity, in the context of immunology and toxicology, refers to the phenomenon where a substance (such as a drug or toxin) or an immune response primarily affects certain organs or tissues in the body. This can occur due to various reasons such as:

1. The presence of specific targets (like antigens in the case of an immune response or receptors in the case of drugs) that are more abundant in these organs.
2. The unique properties of certain cells or tissues that make them more susceptible to damage.
3. The way a substance is metabolized or cleared from the body, which can concentrate it in specific organs.

For example, in autoimmune diseases, organ specificity describes immune responses that are directed against antigens found only in certain organs, such as the thyroid gland in Hashimoto's disease. Similarly, some toxins or drugs may have a particular affinity for liver cells, leading to liver damage or specific drug interactions.

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).

The brainstem is the lower part of the brain that connects to the spinal cord. It consists of the midbrain, pons, and medulla oblongata. The brainstem controls many vital functions such as heart rate, breathing, and blood pressure. It also serves as a relay center for sensory and motor information between the cerebral cortex and the rest of the body. Additionally, several cranial nerves originate from the brainstem, including those that control eye movements, facial movements, and hearing.

Culture media is a substance that is used to support the growth of microorganisms or cells in an artificial environment, such as a petri dish or test tube. It typically contains nutrients and other factors that are necessary for the growth and survival of the organisms being cultured. There are many different types of culture media, each with its own specific formulation and intended use. Some common examples include blood agar, which is used to culture bacteria; Sabouraud dextrose agar, which is used to culture fungi; and Eagle's minimum essential medium, which is used to culture animal cells.

Embryo research refers to the scientific study and experimentation that involves human embryos. This research is conducted in order to gain a better understanding of human development during the earliest stages of life, as well as to investigate potential treatments for various diseases and conditions.

Human embryos used in research are typically created through in vitro fertilization (IVF) procedures, in which sperm and eggs are combined in a laboratory dish to form an embryo. These embryos may be donated by individuals or couples who have undergone IVF treatments and have excess embryos that they do not plan to use for reproduction.

Embryo research can involve a variety of techniques, including stem cell research, genetic testing, and cloning. The goal of this research is to advance our knowledge of human development and disease, as well as to develop new treatments and therapies for a wide range of medical conditions. However, embryo research is a controversial topic, and there are ethical concerns surrounding the use of human embryos in scientific research.

Histones are highly alkaline proteins found in the chromatin of eukaryotic cells. They are rich in basic amino acid residues, such as arginine and lysine, which give them their positive charge. Histones play a crucial role in packaging DNA into a more compact structure within the nucleus by forming a complex with it called a nucleosome. Each nucleosome contains about 146 base pairs of DNA wrapped around an octamer of eight histone proteins (two each of H2A, H2B, H3, and H4). The N-terminal tails of these histones are subject to various post-translational modifications, such as methylation, acetylation, and phosphorylation, which can influence chromatin structure and gene expression. Histone variants also exist, which can contribute to the regulation of specific genes and other nuclear processes.

DNA methylation is a process by which methyl groups (-CH3) are added to the cytosine ring of DNA molecules, often at the 5' position of cytospine phosphate-deoxyguanosine (CpG) dinucleotides. This modification is catalyzed by DNA methyltransferase enzymes and results in the formation of 5-methylcytosine.

DNA methylation plays a crucial role in the regulation of gene expression, genomic imprinting, X chromosome inactivation, and suppression of transposable elements. Abnormal DNA methylation patterns have been associated with various diseases, including cancer, where tumor suppressor genes are often silenced by promoter methylation.

In summary, DNA methylation is a fundamental epigenetic modification that influences gene expression and genome stability, and its dysregulation has important implications for human health and disease.

Intermediate filament proteins (IFPs) are a type of cytoskeletal protein that form the intermediate filaments (IFs), which are one of the three major components of the cytoskeleton in eukaryotic cells, along with microtubules and microfilaments. These proteins have a unique structure, characterized by an alpha-helical rod domain flanked by non-helical head and tail domains.

Intermediate filament proteins are classified into six major types based on their amino acid sequence: Type I (acidic) and Type II (basic) keratins, Type III (desmin, vimentin, glial fibrillary acidic protein, and peripherin), Type IV (neurofilaments), Type V (lamins), and Type VI (nestin). Each type of IFP has a distinct pattern of expression in different tissues and cell types.

Intermediate filament proteins play important roles in maintaining the structural integrity and mechanical strength of cells, providing resilience to mechanical stress, and regulating various cellular processes such as cell division, migration, and signal transduction. Mutations in IFP genes have been associated with several human diseases, including cancer, neurodegenerative disorders, and genetic skin fragility disorders.

Chondrocytes are the specialized cells that produce and maintain the extracellular matrix of cartilage tissue. They are responsible for synthesizing and secreting the collagen fibers, proteoglycans, and other components that give cartilage its unique properties, such as elasticity, resiliency, and resistance to compression. Chondrocytes are located within lacunae, or small cavities, in the cartilage matrix, and they receive nutrients and oxygen through diffusion from the surrounding tissue fluid. They are capable of adapting to changes in mechanical stress by modulating the production and organization of the extracellular matrix, which allows cartilage to withstand various loads and maintain its structural integrity. Chondrocytes play a crucial role in the development, maintenance, and repair of cartilaginous tissues throughout the body, including articular cartilage, costal cartilage, and growth plate cartilage.

In situ hybridization (ISH) is a molecular biology technique used to detect and localize specific nucleic acid sequences, such as DNA or RNA, within cells or tissues. This technique involves the use of a labeled probe that is complementary to the target nucleic acid sequence. The probe can be labeled with various types of markers, including radioisotopes, fluorescent dyes, or enzymes.

During the ISH procedure, the labeled probe is hybridized to the target nucleic acid sequence in situ, meaning that the hybridization occurs within the intact cells or tissues. After washing away unbound probe, the location of the labeled probe can be visualized using various methods depending on the type of label used.

In situ hybridization has a wide range of applications in both research and diagnostic settings, including the detection of gene expression patterns, identification of viral infections, and diagnosis of genetic disorders.

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.

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.

Hepatocytes are the predominant type of cells in the liver, accounting for about 80% of its cytoplasmic mass. They play a key role in protein synthesis, protein storage, transformation of carbohydrates, synthesis of cholesterol, bile salts and phospholipids, detoxification, modification, and excretion of exogenous and endogenous substances, initiation of formation and secretion of bile, and enzyme production. Hepatocytes are essential for the maintenance of homeostasis in the body.

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.

Transplantation conditioning, also known as preparative regimen or immunoablative therapy, refers to the use of various treatments prior to transplantation of cells, tissues or organs. The main goal of transplantation conditioning is to suppress the recipient's immune system, allowing for successful engraftment and minimizing the risk of rejection of the donor tissue.

There are two primary types of transplantation conditioning: myeloablative and non-myeloablative.

1. Myeloablative conditioning is a more intensive regimen that involves the use of high-dose chemotherapy, radiation therapy or both. This approach eliminates not only immune cells but also stem cells in the bone marrow, requiring the recipient to receive a hematopoietic cell transplant (HCT) from the donor to reconstitute their blood and immune system.
2. Non-myeloablative conditioning is a less intensive regimen that primarily targets immune cells while sparing the stem cells in the bone marrow. This approach allows for mixed chimerism, where both recipient and donor immune cells coexist, reducing the risk of severe complications associated with myeloablative conditioning.

The choice between these two types of transplantation conditioning depends on various factors, including the type of transplant, patient's age, overall health, and comorbidities. Both approaches carry risks and benefits, and the decision should be made carefully by a multidisciplinary team of healthcare professionals in consultation with the patient.

A teratoma is a type of germ cell tumor, which is a broad category of tumors that originate from the reproductive cells. A teratoma contains developed tissues from all three embryonic germ layers: ectoderm, mesoderm, and endoderm. This means that a teratoma can contain various types of tissue such as hair, teeth, bone, and even more complex organs like eyes, thyroid, or neural tissue.

Teratomas are usually benign (non-cancerous), but they can sometimes be malignant (cancerous) and can spread to other parts of the body. They can occur anywhere in the body, but they're most commonly found in the ovaries and testicles. When found in these areas, they are typically removed surgically.

Teratomas can also occur in other locations such as the sacrum, coccyx (tailbone), mediastinum (the area between the lungs), and pineal gland (a small gland in the brain). These types of teratomas can be more complex to treat due to their location and potential to cause damage to nearby structures.

Embryoid bodies are aggregates of pluripotent stem cells, such as embryonic stem cells or induced pluripotent stem cells, that have been cultured in suspension and allowed to differentiate spontaneously into three-dimensional structures. These structures resemble early embryonic development and can contain cells from all three germ layers: ectoderm, mesoderm, and endoderm. Embryoid bodies are often used as a tool in stem cell research to study the processes of differentiation and organogenesis.

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.

Cell adhesion refers to the binding of cells to extracellular matrices or to other cells, a process that is fundamental to the development, function, and maintenance of multicellular organisms. Cell adhesion is mediated by various cell surface receptors, such as integrins, cadherins, and immunoglobulin-like cell adhesion molecules (Ig-CAMs), which interact with specific ligands in the extracellular environment. These interactions lead to the formation of specialized junctions, such as tight junctions, adherens junctions, and desmosomes, that help to maintain tissue architecture and regulate various cellular processes, including proliferation, differentiation, migration, and survival. Disruptions in cell adhesion can contribute to a variety of diseases, including cancer, inflammation, and degenerative disorders.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

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.

'Cellular spheroids' refer to three-dimensional (3D) aggregates of cells that come together to form spherical structures. These spheroids can be formed by various cell types, including cancer cells, stem cells, and primary cells, and they are often used as models to study cell-cell interactions, cell signaling, drug development, and tumor biology in a more physiologically relevant context compared to traditional two-dimensional (2D) cell cultures.

Cellular spheroids can form spontaneously under certain conditions or be induced through various methods such as hanging drop, spinner flask, or microfluidic devices. The formation of spheroids allows cells to interact with each other and the extracellular matrix in a more natural way, leading to the creation of complex structures that mimic the organization and behavior of tissues in vivo.

Studying cellular spheroids has several advantages over traditional 2D cultures, including better preservation of cell-cell interactions, improved modeling of drug penetration and resistance, and enhanced ability to recapitulate the complexity of tumor microenvironments. As a result, cellular spheroids have become an important tool in various areas of biomedical research, including cancer biology, tissue engineering, and regenerative medicine.

Chromatin is the complex of DNA, RNA, and proteins that make up the chromosomes in the nucleus of a cell. It is responsible for packaging the long DNA molecules into a more compact form that fits within the nucleus. Chromatin is made up of repeating units called nucleosomes, which consist of a histone protein octamer wrapped tightly by DNA. The structure of chromatin can be altered through chemical modifications to the histone proteins and DNA, which can influence gene expression and other cellular processes.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

Graft-versus-host disease (GVHD) is a condition that can occur after an allogeneic hematopoietic stem cell transplantation (HSCT), where the donated immune cells (graft) recognize the recipient's tissues (host) as foreign and attack them. This results in inflammation and damage to various organs, particularly the skin, gastrointestinal tract, and liver.

Acute GVHD typically occurs within 100 days of transplantation and is characterized by symptoms such as rash, diarrhea, and liver dysfunction. Chronic GVHD, on the other hand, can occur after 100 days or even years post-transplant and may present with a wider range of symptoms, including dry eyes and mouth, skin changes, lung involvement, and issues with mobility and flexibility in joints.

GVHD is a significant complication following allogeneic HSCT and can have a substantial impact on the patient's quality of life and overall prognosis. Preventative measures, such as immunosuppressive therapy, are often taken to reduce the risk of GVHD, but its management remains a challenge in transplant medicine.

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.

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.

Inbred NOD (Nonobese Diabetic) mice are a strain of laboratory mice that are genetically predisposed to develop autoimmune diabetes. This strain was originally developed in Japan and has been widely used as an animal model for studying type 1 diabetes and its complications.

NOD mice typically develop diabetes spontaneously at around 12-14 weeks of age, although the onset and severity of the disease can vary between individual mice. The disease is caused by a breakdown in immune tolerance, leading to an autoimmune attack on the insulin-producing beta cells of the pancreas.

Inbred NOD mice are highly valuable for research purposes because they exhibit many of the same genetic and immunological features as human patients with type 1 diabetes. By studying these mice, researchers can gain insights into the underlying mechanisms of the disease and develop new treatments and therapies.

Cell tracking is a technique used in medical research and clinical applications to monitor the movement, behavior, and fate of cells over time. This process typically involves labeling cells with a marker such as a dye, fluorescent protein, or magnetic nanoparticle, which allows researchers to observe and analyze the cells using various imaging techniques.

The labeled cells can be tracked individually or in groups, enabling the study of cell-cell interactions, migration patterns, proliferation rates, and other biological processes. Cell tracking has numerous applications in fields such as regenerative medicine, cancer research, developmental biology, and drug discovery.

There are different methods for cell tracking, including:

1. Intravital microscopy: This technique involves surgically implanting a microscope into a living organism to directly observe cells in their native environment over time.
2. Two-photon microscopy: Using laser pulses to excite fluorescent markers, this method allows for deep tissue imaging with minimal photodamage.
3. Magnetic resonance imaging (MRI): By labeling cells with magnetic nanoparticles, researchers can use MRI to non-invasively track cell movement and distribution within an organism.
4. Positron emission tomography (PET) and computed tomography (CT) scans: Radioactive tracers can be used to label cells for tracking via PET or CT imaging techniques.
5. Image analysis software: Specialized software can be used to analyze images captured through various imaging techniques, enabling researchers to track cell movement and behavior over time.

Overall, cell tracking is an essential tool in medical research, providing valuable insights into the dynamics of cellular processes and contributing to advancements in diagnostic and therapeutic strategies.

Granulocyte Colony-Stimulating Factor (G-CSF) is a type of growth factor that specifically stimulates the production and survival of granulocytes, a type of white blood cell crucial for fighting off infections. G-CSF works by promoting the proliferation and differentiation of hematopoietic stem cells into mature granulocytes, primarily neutrophils, in the bone marrow.

Recombinant forms of G-CSF are used clinically as a medication to boost white blood cell production in patients undergoing chemotherapy or radiation therapy for cancer, those with congenital neutropenia, and those who have had a bone marrow transplant. By increasing the number of circulating neutrophils, G-CSF helps reduce the risk of severe infections during periods of intense immune suppression.

Examples of recombinant G-CSF medications include filgrastim (Neupogen), pegfilgrastim (Neulasta), and lipegfilgrastim (Lonquex).

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.

CD24 is a cell surface glycoprotein that serves as a marker for B cells at various stages of development and differentiation. It is also expressed on the surface of certain other cell types, including neutrophils and some cancer cells. Antigens are substances that can stimulate an immune response and are recognized as foreign by the body's immune system. CD24 is not typically referred to as an antigen itself, but it can be used as a target for immunotherapy in certain types of cancer. In this context, monoclonal antibodies or other immune-based therapies may be developed to specifically recognize and bind to CD24 on the surface of cancer cells, with the goal of triggering an immune response against the cancer cells.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

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.

Heterologous transplantation is a type of transplantation where an organ or tissue is transferred from one species to another. This is in contrast to allogeneic transplantation, where the donor and recipient are of the same species, or autologous transplantation, where the donor and recipient are the same individual.

In heterologous transplantation, the immune systems of the donor and recipient are significantly different, which can lead to a strong immune response against the transplanted organ or tissue. This is known as a graft-versus-host disease (GVHD), where the immune cells in the transplanted tissue attack the recipient's body.

Heterologous transplantation is not commonly performed in clinical medicine due to the high risk of rejection and GVHD. However, it may be used in research settings to study the biology of transplantation and to develop new therapies for transplant rejection.

The limbus cornea, also known as the corneoscleral junction, is the border between the transparent cornea and the opaque sclera in the eye. It's a circular, narrow region that contains cells called limbal stem cells, which are essential for maintaining the health and clarity of the cornea. These stem cells continuously regenerate and differentiate into corneal epithelial cells, replacing the outermost layer of the cornea. Any damage or disorder in this area can lead to vision impairment or loss.

Embryonal carcinoma stem cells (ECSCs) are a type of cancer stem cell found in embryonal carcinomas, which are a rare form of germ cell tumor that primarily affect the testicles and ovaries. These stem cells are characterized by their ability to differentiate into various cell types, similar to embryonic stem cells. They are believed to play a key role in the development and progression of embryonal carcinomas, as they can self-renew and generate the heterogeneous population of cancer cells that make up the tumor.

Embryonal carcinoma stem cells have been studied extensively as a model system for understanding the biology of cancer stem cells and developing new therapies for germ cell tumors. They are known to express specific markers, such as Oct-4, Nanog, and Sox2, which are also expressed in embryonic stem cells and are involved in maintaining their pluripotency.

It is important to note that while embryonal carcinoma stem cells share some similarities with embryonic stem cells, they are distinct from them and have undergone malignant transformation, making them a target for cancer therapy.

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.

DNA damage refers to any alteration in the structure or composition of deoxyribonucleic acid (DNA), which is the genetic material present in cells. DNA damage can result from various internal and external factors, including environmental exposures such as ultraviolet radiation, tobacco smoke, and certain chemicals, as well as normal cellular processes such as replication and oxidative metabolism.

Examples of DNA damage include base modifications, base deletions or insertions, single-strand breaks, double-strand breaks, and crosslinks between the two strands of the DNA helix. These types of damage can lead to mutations, genomic instability, and chromosomal aberrations, which can contribute to the development of diseases such as cancer, neurodegenerative disorders, and aging-related conditions.

The body has several mechanisms for repairing DNA damage, including base excision repair, nucleotide excision repair, mismatch repair, and double-strand break repair. However, if the damage is too extensive or the repair mechanisms are impaired, the cell may undergo apoptosis (programmed cell death) to prevent the propagation of potentially harmful mutations.

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).

... such as mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, etc.). A great deal of adult stem cell ... The extracted stem cells are known as human adult germline stem cells (GSCs) Multipotent stem cells have also been derived from ... There are three main methods to determine if the adult stem cell is capable of becoming a specialized cell. The adult stem cell ... 6 August 2013). "Do pluripotent stem cells exist in adult mice as very small embryonic stem cells?". Stem Cell Reports. 1 (2): ...
... and such research involves adult stem cells, amniotic stem cells, and induced pluripotent stem cells. On 23 January 2009, the ... Fetal tissue implant Induced pluripotent stem cell Induced stem cells Stem cell chip Stem cell therapy for macular degeneration ... Healthy adult brains contain neural stem cells, which divide to maintain general stem-cell numbers, or become progenitor cells ... "Selling Stem Cells in the USA: Assessing the Direct-to-Consumer Industry". Cell Stem Cell. 19 (2): 154-157. doi:10.1016/j.stem. ...
... from adult cells. These are not adult stem cells, but somatic cells (e.g. epithelial cells) reprogrammed to give rise to cells ... Mesenchymal stem cell Ovarian stem cell Partial cloning Plant stem cell Stem cell controversy Stem cell marker Stem cell laws ... mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, dental pulp stem cell, etc.). Muse cells (multi- ... Adult stem cells, also called somatic (from Greek σωματικóς, "of the body") stem cells, are stem cells which maintain and ...
Stem cell Embryonic stem cell Induced pluripotent stem cell Induced stem cells Adult stem cell Cell culture Immortalised cell ... Types of adult stem cells include hematopoietic stem cells and mesenchymal stem cells. Hematopoietic stem cells are found in ... Adult stem cells are found in juvenile or adult tissues. Adult stem cells are multipotent: they can generate a limited number ... embryonic stem cells, adult stem cells, or induced stem cells. They are commonly used in research and regenerative medicine. By ...
"The renal papilla is a niche for adult kidney stem cells". Journal of Clinical Investigation. 114 (6): 795-804. doi:10.1172/ ... Renal stem cells are self-renewing, multipotent stem cells which are able to give rise to all the cell types of the kidney. It ... "Intrinsic Epithelial Cells Repair the Kidney after Injury". Cell Stem Cell. 2 (3): 284-91. doi:10.1016/j.stem.2008.01.014. PMID ... Thus, Lgr5+ cells can potentially be a marker for renal stem and/or progenitor cells. There is much debate regarding the cells ...
Endogenous cardiac stem cells (eCSCs) are tissue-specific stem progenitor cells harboured within the adult mammalian heart. It ... 2003). "Adult cardiac stem cells are multipotent and support myocardial regeneration". Cell. 114 (6): 763-776. doi:10.1016/ ... 2003). "Adult cardiac stem cells are multipotent and support myocardial regeneration". Cell. 114 (6): 763-776. doi:10.1016/ ... Endogenous cardiac stem cells were first discovered in 2003 by Bernardo Nadal-Ginard, Piero Anversa and colleagues in the adult ...
December 2006). "Isolation of multipotent neural crest-derived stem cells from the adult mouse cornea". Stem Cells. 24 (12): ... Stem cell markers are genes and their protein products used by scientists to isolate and identify stem cells. Stem cells can ... 2005). "Somatic stem cell marker prominin-1/CD133 is expressed in embryonic stem cell-derived progenitors". Stem Cells. 23 (6 ... December 2006). "Isolation and characterization of a stem cell population from adult human liver". Stem Cells. 24 (12): 2840-50 ...
In April 2013, Hemmer spent a week at the Vatican moderating the Second Annual Adult Stem Cell Research Conference and in May ... "Bill Hemmer , Adult Stem Cell Conference 2013". adultstemcellconference.org. "News - Miami University". www.fsb.miamioh.edu. " ...
June 2014). "Human somatic cell nuclear transfer using adult cells". Cell Stem Cell. 14 (6): 777-80. doi:10.1016/j.stem.2014.03 ... specialized adult cells can naturally revert to stem cells. For example, "chief" cells express the stem cell marker Troy. While ... Scientists develop 'game changing' stem cell repair system. Stem Cells Portal Could this new stem cell become the game changer ... July 2010). "Reprogramming of human peripheral blood cells to induced pluripotent stem cells". Cell Stem Cell. 7 (1): 20-4. doi ...
"Hedgehog signaling is required for adult blood stem cell formation in zebrafish embryos". Dev. Cell. 8 (3): 389-400. doi: ... Cell Stem Cell. 7 (3): 391-402. doi:10.1016/j.stem.2010.06.020. PMID 20804974. Adams GB; et al. (2006). "Stem cell engraftment ... 2010). "The distinct metabolic profile of hematopoietic stem cells reflects their location in a hypoxic niche". Cell Stem Cell ... immune cells, and even platelets all originate from the same progenitor cell, the hematopoietic stem cell (HSC). As these cells ...
The publication of a study in 2004 proposing germ cell renewal in adult mice sparked a debate on the possibility of stem cells ... However, scientists that do believe ovarian stem cells exist have described the stem cells as having the ability to finish ... Telfer EE, Anderson RA (February 2019). "The existence and potential of germline stem cells in the adult mammalian ovary". ... Markers for ovarian stem cells are also a source of contention. Markers previously used are: DDX4 STRA-8 SCP-3 SPO 11 Dmc 1 ...
... adult stem cell pioneer James Fallon; Michael D. West, gerontologist and stem cell scientist, founder of Geron, now CEO of ... It involves using biocatalysis and synthetic biology tools to block or supplement the actions of specific cells or proteins in ...
"Adult stem cells restore sight - BioNews". www.bionews.org.uk. "ESCRS Endophthalmitis Study results highlight annual meeting in ... The technique of stem cell transplantaction was shown in the documentary film The Science of Seeing Again. In 2009 Daya ... Daya founded the Centre for Sight in 1996, and works in stem-cell research and sight recovery surgery. Daya graduated from the ... Daya has also used stem cell treatment during corneal transplant surgeries, and was the world's first person to perform live ...
Mobley AS (January 2019). "Chapter 4 - Induced Pluripotent Stem Cells". In Mobley AS (ed.). Neural Stem Cells and Adult ... There is therefore a direct link to how actively productive a cell is and the amount of euchromatin that can be found in its ... It is thought that the cell uses transformation from euchromatin into heterochromatin as a method of controlling gene ... ISBN 978-0-12-811014-0. "The cell. 4. Nucleus. Chromatin. Atlas of plant and animal histology". mmegias.webs.uvigo.es. ...
Neuroscientist and stem cell biologist; discovered human adult neural stem cells. Clark Gibson, Political Science. Expert on ... First to characterize kinesin molecular motors; head of UCSD stem cell research program. Jean-Pierre Gorin, Visual Arts. Film ... Romanian-born scientist who won the Nobel Prize for his work on the structure and function of cells, The Guardian, Retrieved 23 ... Diochemist known for his work on the molecular basis of sickle cell anemia and other diseases. Gabriel Jackson, History. ...
In 2020 he was also appointed as Head of the Adult Stem Cell laboratory at the ICR in London and Professor of cancer biology at ... "Axel Behrens Adult stem cell laboratory". Retrieved 29 Mar 2021. The Francis Crick Institute. "Axel Behrens- Lgr6 marks a ... to head up the Adult Stem Cell Laboratory. In 2020, Prof Behrens became the inaugural Scientific Director of the Cancer ... with the so-called cancer stem cells (CSC), also called tumour initiating cells (TICs), being at the apex. It is believed that ...
As a result, many researchers have focused on adult stem cells, or stem cells isolated from adult humans that can be ... and nucleated cells. The adult stem cell fraction is present in the nucleated cells of the marrow. Most of these cells are ... Mesenchymal stem cells (MSCs) are multipotent cells found in multiple human adult tissues, including bone marrow, synovial ... meaning they are cells that have the ability to develop into more than one type of specialized cell. Mesenchymal stem cells ...
July 2002). "Pluripotency of mesenchymal stem cells derived from adult marrow". Nature. 418 (6893): 41-9. Bibcode:2002Natur.418 ... May 2012). "Mesenchymal-stem-cell-induced immunoregulation involves FAS-ligand-/FAS-mediated T cell apoptosis". Cell Stem Cell ... "Mesenchymal stem cells: revisiting history, concepts, and assays". Cell Stem Cell. 2 (4): 313-319. doi:10.1016/j.stem.2008.03. ... "Mesenchymal stem cell-mediated immunosuppression occurs via concerted action of chemokines and nitric oxide". Cell Stem Cell. 2 ...
The result showed that (A) 90% of the clinics use Autologous adult stem cell. (B) 71% of clinics obtained stem cells were from ... "Stem cell homing: From physiology to therapeutics". Stem Cells. 38 (10): 1241-1253. doi:10.1002/stem.3242. PMID 32526037. ... The stem cell market has grown largely along with the increasing awareness of stem cells in regenerative medicine. The Google ... Stem cell fat grafting is autotransplantation of adipose-derived stem cells (ADSCs) extracted from fat-abundant donor sites (i. ...
"Adult stem cells could treat tooth loss". The Royal Society. Retrieved 27 May 2020. "Methods of Cell Separation". Elsevier. ... Sharpe is author of Methods of Cell Separation. Sharpe is an Honorary Fellow of the Royal College of Surgeons in Edinburgh ( ... Sharpe, PT; Watts, DJ (1985). "Use of aqueous two-phase partition to detect cell surface changes during growth of D. discoideum ... Sharpe, PT; Gallagher, JA; Treffry, TE; Russell, RGG (1982). "Studies of the growth of human bone-derived cells in culture ...
August 2007). "MIO-M1 cells and similar muller glial cell lines derived from adult human retina exhibit neural stem cell ... February 2008). "Transparent adult zebrafish as a tool for in vivo transplantation analysis". Cell Stem Cell. 2 (2): 183-189. ... "Adult Stem Cell Research Avoids Ethical Concerns". Voice of America. 19 May 2010. Retrieved 21 June 2013. Plantié E, Migocka- ... In 2007, researchers at University College London grew a type of zebrafish adult stem cell found in the eyes of fish and ...
"Generation of functional blood vessels from a single c-kit+ adult vascular endothelial stem cell". PLOS Biology. 10 (10): ... These parent stem cells, ESCs, give rise to progenitor cells, which are intermediate stem cells that lose potency. Progenitor ... Endothelial stem cells (ESCs) are one of three types of stem cells found in bone marrow. They are multipotent, which describes ... For stem cells, this usually occurs through several stages, when a cell proliferates giving rise to daughter cells that are ...
Woods, Dori C.; White, Yvonne A. R.; Tilly, Jonathan L. (2013-01-01). "Purification of Oogonial Stem Cells From Adult Mouse and ... Oogonial stem cells (OSCs), also known as egg precursor cells or female germline cells, are diploid germline cells with stem ... have found no supporting evidence for oogonial stem cells. "stem cell - definition of stem cell in English , Oxford ... Dunlop, Cheryl E.; Telfer, Evelyn E.; Anderson, Richard A. (2014-01-01). "Ovarian germline stem cells". Stem Cell Research & ...
Their enhanced stability and plasticity compared to adult stem cells may also be an advantage. Stem cells from both the ... This characteristic differentiates them from embryonic stem cells but indicates similarities with adult stem cells. However, ... Evidence in favour of their embryonic stem cell nature is the cells' ability to produce clones. The use of amniotic stem cells ... Amniotic stem cells are the mixture of stem cells that can be obtained from the amniotic fluid as well as the amniotic membrane ...
This article includes description of the adult stem cell harvesting method that provided Osiris a competitive advantage over ... A peer company, StemCells, emerged in 1995 in California with a focus on neural regeneration, but using stem cell technology ... "Multilineage Potential of Adult Human Mesenchymal Stem Cells". Science. 284 (5411): 143-7. doi:10.1126/science.284.5411.143. ... At the time of the IPO, Osiris was considered to be "the closest in (the United States) to bring a pure stem cell product to ...
... regulates adult neural stem cell proliferation. Removal of TLX from the adult mouse brain resulted in a reduction of stem ... Tlx-positive cells of the subventricular zone of adult mouse brain are self-renewing stem cells. Mutation of the Tlx gene in ... Adult neural stem cells are nuclear receptor TLX-positive and TLX expression in these cells is crucial in maintaining their ... Zhang CL, Zou Y, He W, Gage FH, Evans RM (February 2008). "A role for adult TLX-positive neural stem cells in learning and ...
"Multilineage potential of adult human mesenchymal stem cells". Science. 284 (5411): 143-7. Bibcode:1999Sci...284..143P. doi: ... It has been suggested that differentiating embryonic stem cells with these growth factors could prevent stem cells, once ... These cells, when forming from the mesoderm, specifically form from embryonic stem cells via induction through BMP4 and ... Chondroblasts, or perichondrial cells, is the name given to mesenchymal progenitor cells in situ which, from endochondral ...
In the adult intestine, the crypts of Lieberkühn are the niche for epithelial stem cells and contain all proliferative stem and ... these cells are also called quiescent stem cells. The stem cell zone model states that the CBC stem cells reside in a stem-cell ... "The Intestinal Stem Cell Signature Identifies Colorectal Cancer Stem Cells and Predicts Disease Relapse". Cell Stem Cell. 8 (5 ... "Identifying the Stem Cell of the Intestinal Crypt: Strategies and Pitfalls". Cell Stem Cell. 11 (4): 452-460. doi:10.1016/j. ...
Concurrent vasculogenesis and neurogenesis from adult neural stem cells. Ii M, Nishimura H, Sekiguchi H, Kamei N, Yokoyama A, ...
Bon-Kyoung Koo: Homeostatic regulation of adult stem cells. Pioneer in adult stem cell organoids. Sasha Mendjan: Molecular ... IMBA and the IMP co-organize the yearly SY-Stem symposium focusing on the next generation of stem cell researchers. The Vienna ... Functional genomics in embryonic stem cells. Developer of Haplobank. Daniel Gerlich: Assembly and function of the cell division ... Generation of blood vessel organoids from human pluripotent stem cells. 2017. Development of SLAM-Seq for the high-resolution ...
... such as mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, etc.). A great deal of adult stem cell ... The extracted stem cells are known as human adult germline stem cells (GSCs) Multipotent stem cells have also been derived from ... There are three main methods to determine if the adult stem cell is capable of becoming a specialized cell. The adult stem cell ... 6 August 2013). "Do pluripotent stem cells exist in adult mice as very small embryonic stem cells?". Stem Cell Reports. 1 (2): ...
... have identified retinal stem cells in the adult mammalian eye, opening the door for retinal regeneration as a possible cure for ... When it comes to stem cells, it appears the eyes have it. Researchers at the University of Toronto and the Hospital for Sick ... Cell Fusion awakens Regenerative Potential of Human Retina. Mar. 15, 2022 Fusing human retinal cells with adult stem cells ... Researchers Discover Retinal Stem Cells In Adult Mammals. Date:. March 17, 2000. Source:. University Of Toronto. Summary:. When ...
... Georg-Speyer-Haus Symposium: Dynamics of adult stem cells and cancer. SAVE ... Beim diesjährigen Symposiums steht das Thema „Dynamics of adult stem cells and cancer" im Fokus: In der heutigen Krebsmedizin ... Dynamics of adult stem cells and cancer will take place on October 25-26, 2017 (Wednesday afternoon - Thursday evening) at the ...
These adult-born neurons become functionally active and are thought to contribute to learning and memory, especially during ... Adult Neurogenesis in the Hippocampus: From Stem Cells to Behavior Cell. 2016 Nov 3;167(4):897-914. doi: 10.1016/j.cell.2016.10 ... we discuss the molecular machinery involved in the generation of new neurons from a pool of adult neural stem cells and their ... DOI: 10.1016/j.cell.2016.10.021 Abstract The dentate gyrus of the mammalian hippocampus continuously generates new neurons ...
This week two scientists have received the Nobel Prize for their work on a study which has adult cells transformed back into ... Stem cells that come from adult cells such as these are known as "induced pluripotency stem cells" - aka iPS cells - and will ... If the studies conducted by the scientists here are able to turn adult cells back into cells that regenerate like stem cells, ... In 2006, Yamanaka was able to produce mouse stem cells from an adult mouses skin cells with an insertion of a set of genes. ...
It was incredible: adult stem cells help paralyzed woman walk again. Laura Dominguez-Tauer can feel her body again. She got ... "Thanks to adult stem cell treatment and [Lauras] spirit of determination, she has her mobility, her sensation, and her dreams ... "Adult stem cells have shown validated success in treating the most intractable conditions - not only spinal cord injury, but ... She underwent an experimental procedure using her own adult stem cells and is now able to walk with the help of a walker. ...
... efforts to grow whole organs from stem cells. They have already grown tendons, cartilages and bladders from adult stem cells. ... Bone marrow stem cells have been used to create heart valve cells, raising hopes that an entire heart could be grown from stem ... extracted stem cells from bone marrow, cultivated them into heart valve cells, and the placed them on biodegradable "scaffolds ... Utahs new stem cell law undermines FDAs authority The state of Utah has just enacted a law permitting patients to receive ...
Adult neurogenesis was found in almost all mammals and was extensively studied in rodents. In spite of the vast knowledge ... The presence of adult neurogenesis in humans spurs hope for brain regeneration and changed the view of the brain as an ... The aim of this project is to show beyond doubt whether neural progenitors and stem cell niches are present in the adult human ... medical and health sciencesmedical biotechnologycells technologiesstem cells. *medical and health sciencesclinical medicine ...
adult neural stem cellsadult stem cellsGeneticsneural stem cellsneuronsNeuroscienceNSCsstem cells ... Most adult stem cells are also self-renewing. When a stem cell divides into two, one daughter cell remains as an ... The researchers had another surprise, having to do with the relationship between embryonic stem cells and adult stem cells. ... the scientists found that the mouse adult neural stem cells they studied are derived from embryonic neural stem cells that ...
Watch this Scientific Journal Video about Isolation and Culture of Adult Neural Stem Cells from the Mouse Subcallosal Zone at ... Isolation Culture Adult Neural Stem Cells Mouse Subcallosal Zone Nonadherent Culture System Adherent Culture System Brain ... Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation… ... Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation… ...
... is a transcriptional regulator of neural stem cell expansion in the adult hippocampus. ... 2015) CHD7 maintains neural stem cell quiescence and prevents premature stem cell depletion in the adult hippocampus Stem Cells ... 2016) Proximity-Based Differential Single-Cell Analysis of the Niche to Identify Stem/Progenitor Cell Regulators Cell Stem Cell ... 2015) Single-Cell RNA-Seq with Waterfall Reveals Molecular Cascades underlying Adult Neurogenesis Cell Stem Cell 17:360-372. ...
... cardiologist reports the successful treatment of patients with cardiovascular disease using autologous adult stem cells. ... We have moved beyond bench research and clinical trials to show that the power of the bodys adult stem cells can be harnessed ... The procedure involves the simple drawing of blood from which the adult stem cells are isolated and then expanded in the ... Grekos announced that his team of physicians and scientists also used autologous adult stem cells in the successful treatment ...
haematopoietic stem cell transplantation. Introduction. Adult-onset leukoencephalopathy with axonal spheroids and pigmented ... Haematopoietic stem cell transplantation in CSF1R-related adult-onset leukoencephalopathy with axonal spheroids and pigmented ... Haematopoietic stem cell transplantation in CSF1R-related adult-onset leukoencephalopathy with axonal spheroids and pigmented ... We hypothesised that haematopoietic stem cell transplantation (HSCT) can be relevant in ALSP by correcting CSF1R loss-of- ...
... allogeneic stem cell transplantation, allotransplantation, antineoplastic agent, article, autologous stem cell transplantation, ... Myeloablative allogeneic versus autologous stem cell transplantation in adult patients with acute lymphoblastic leukemia in ... the role of allogeneic hematopoietic stem cell transplantation (allo-SCT) is still disputed in adult patients with standard- ... Myeloablative allogeneic versus autologous stem cell transplantation in adult patients with acute lymphoblastic leukemia in ...
Yale Stem Cell Center. Eugene Higgins Professor & Director Yale Stem Cell Institute (2019) ... The neural crest, a source of stem cells, its role in development and evolution of vertebrates ... Stanford Medicine Baxter Laboratory for Stem Cell Biology - in the Department of Microbiology & Immunology Site Nav Menu ... Baxter Laboratory for Stem Cell Biology , Stanford University School of Medicine. 269 Campus Drive, CCSR Building Room 4215 , ...
Adult stem cells. Adult stem cells are unspecialized, can renew themselves, and can become specialized to yield all of the cell ... Therapies from adult and embryonic stem cell research. To date, adult stem cell research, which is federally-funded, has ... Although scientists believe that some adult stem cells from one tissue can develop into cells of another tissue, no adult stem ... The creation of embryonic stem cells. To create embryonic stem cells for research, a "stem cell line" must be created from the ...
Researchers are learning about mending a broken heart by generating healthy heart muscle stem cells in the laboratory and then ... A number of stem cell types, including cardiac stem cells that naturally reside within the heart, myoblasts (muscle stem cells ... Tagged under: broken heart, heart muscle stem cells, shtem cells heart disease, stem cells diabetes. ... Can Stem Cells Mend a Broken Heart? For that matter, what can stem cells do to treat all cardiovascular diseases including ...
... on the ethical problems of embryonic stem cell research. A biblical view of life gives a distinct take on this research. ... Adult stem cells continue to outperform embryonic stem cells.. Stem Cells and the Last Election. The first human embryonic stem ... and other types of stem cells in your body. These are referred to as adult stem cells. Other common types of stem cells are ... We fully support adult stem cell research, but even if adult stem cells prove problematic in some cases I would still not ...
Project title: Modeling NETs using adult stem cell-derived organoids Hans Clevers, MD, PhD Hubrecht Institute, Netherlands ...
Researchers convert adult cells to hair generating stem cells to beat the bald 30-Jan-2014. By Andrew MCDOUGALL ... Stem cell procedures - the next Botox? 21-Feb-2005. Research at the University of Illinois at Chicago indicates that stem cell ... National Stem Cell Holding has changed its name to Proteonomix a month after launching a stem cell based cosmeceutical line ... researchers have come up with a method to convert adult cells into epithelial stem cells for the first time. ...
... profile, educations, publications, ... define the quality of the cells, and then distribute them to multiple investigators. The adult stem/progenitor cells we prepare ... This a competing renewal application (Type 2) for a Center to prepare adult stem/progenitor cells from the bone marrow of human ... subsequently as mesenchymal stem cells, and most recently as multipotent mesenchymal stromal cells or MSCs. Since the last ...
Specifically, the aim of these studies was to characterize different means by which the differentiation of adult stem cells ... investigated the possibility of using the scaffold material and cell size to modulate the differentiation of adult stem cells. ... Tissue engineering is a relatively new technique which has the potential to deliver a cell-based device which can overcome the ... The goal of these studies is to employ the principles of tissue engineering to better comprehend the interaction between cells ...
1997). Hemopoietic stem cell transplantation (HSCT) after intensive chemotherapy (CT) in adult patients with primary acute ... 1997, Hemopoietic stem cell transplantation (HSCT) after intensive chemotherapy (CT) in adult patients with primary acute ... Hemopoietic stem cell transplantation (HSCT) after intensive chemotherapy (CT) in adult patients with primary acute myeloid ... Hemopoietic stem cell transplantation (HSCT) after intensive chemotherapy (CT) in adult patients with primary acute myeloid ...
The neural stem cells (NSCs) were isolated from hippocampus of APP/PS1 transgenic mice at E14, and the cells were treated with ... Our study demonstrates that PBMT, as a viable therapeutic strategy, directs the adult hippocampal APP/PS1 NSCs differentiate ... Adult hippocampal neurogenesis (AHN) is restricted under the pathological conditions of neurodegenerative diseases, especially ... Adult mammalian neural stem cells and neurogenesis: five decades later. Cell stem cell. 2015;17(4):385-95. https://doi.org/ ...
The finding proves that a population of stem cells exists in the adult prostate, as many have long suspected, and it could ... A single adult stem cell from the prostate of a mouse can develop into an entire functional organ, scientists reported online ... have much in common with normal adult stem cells. Some even suspect that cancer stem cells and normal stem cells are one and ... the newly isolated prostate stem cells may provide insight into adult stem cells in general. "Our understanding of stem cells- ...
... provides a unique opportunity to explore how evolution has shaped adult stem cell (ASC) activity and tissue function with ... CBC cells. Instead of entering quiescence (G0), NMR Lgr5+CBC cells reduce their division rates by prolonging arrest in the G1 ... we find an expanded pool of Lgr5+ cells in NMRs, and these cells specifically at the crypt base (Lgr5+CBC) exhibit slower ... anti-proliferative response within the stem/progenitor cell zone. ... we also observe a higher proportion of differentiated cells in ...
Critical role of Jak2 in the maintenance and function of adult hematopoietic stem cells. In: STEM CELLS. 2014 ; Vol. 32, No. 7 ... Critical role of Jak2 in the maintenance and function of adult hematopoietic stem cells, STEM CELLS, vol. 32, no. 7, pp. 1878- ... Critical role of Jak2 in the maintenance and function of adult hematopoietic stem cells. STEM CELLS. 2014 Jul;32(7):1878-1889. ... Stem Cells 2014;32:1878-1889",. keywords = "Apoptosis, Conditional knockout, Hematopoietic stem cells, JAK2 kinase, ...
Adult stem cells: assessing the case for pluripotency. Trends Cell Biol. 12(11):502-508., Meirelles et al. 2006Meirelles L.S., ... Adult stem cells: assessing the case for pluripotency. Trends Cell Biol. 12(11):502-508. ... Mesenchymal stem-cell cultures. Mesenchymal stem cells (MSC) were collected by the Immunogenetics Laboratory of the Federal ... Turning brain into blood: a hematopoietic fate adopted by adult neural stem cells in vivo. Science 283(5401):534-537., Shi et ...
Cardiology Stem Cells Market is expected to surpass the value US$ 5.1 Bn by 2031, expanding at a CAGR of 7.4% during the ... In terms of type of cell, the adult stem cells segment dominated the global cardiology stem cells market in 2022. Adult stem ... Advancement in Stem Cell Research Driving Global Cardiology Stem Cells Market Share. Advances in stem cell research have led to ... including cardiology stem cells. Induced pluripotent stem cells (iPSCs) are adult cells that have been reprogrammed to become ...
Stem cell therapy certainly has benefits of its own. But what are they and why should you opt for it? Let us find it out in ... Well, stem cells can be divided into two major forms. These include adult and embryonic stem cells. Typically, adult stem cells ... Stem cells source. How Long It Takes for the Therapy to Work. There is no evidence that stem cell clinics provide stem cell ... Stem cell therapy is basically a kind of regenerative medicine. It primarily uses stem cells to treat heal a patients body. If ...

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