An enzyme that catalyzes the hydrolysis of ADENOSINE to INOSINE with the elimination of AMMONIA.
Drugs that inhibit ADENOSINE DEAMINASE activity.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
Catalyze the hydrolysis of nucleosides with the elimination of ammonia.
A ribonucleoside antibiotic synergist and adenosine deaminase inhibitor isolated from Nocardia interforma and Streptomyces kaniharaensis. It is proposed as an antineoplastic synergist and immunosuppressant.
An enzyme that catalyzes the deamination of AMP to IMP. EC 3.5.4.6.
A potent inhibitor of ADENOSINE DEAMINASE. The drug induces APOPTOSIS of LYMPHOCYTES, and is used in the treatment of many lymphoproliferative malignancies, particularly HAIRY CELL LEUKEMIA. It is also synergistic with some other antineoplastic agents and has immunosuppressive activity.
A subclass of adenosine A2 receptors found in LEUKOCYTES, the SPLEEN, the THYMUS and a variety of other tissues. It is generally considered to be a receptor for ADENOSINE that couples to the GS, STIMULATORY G-PROTEIN.
An enzyme that catalyzes the formation of ADP plus AMP from adenosine plus ATP. It can serve as a salvage mechanism for returning adenosine to nucleic acids. EC 2.7.1.20.
A subtype of ADENOSINE RECEPTOR that is found expressed in a variety of tissues including the BRAIN and DORSAL HORN NEURONS. The receptor is generally considered to be coupled to the GI, INHIBITORY G-PROTEIN which causes down regulation of CYCLIC AMP.
An enzyme that catalyzes the deamination of cytidine, forming uridine. EC 3.5.4.5.
Adenosine molecules which can be substituted in any position, but are lacking one hydroxyl group in the ribose part of the molecule.
A purine nucleoside that has hypoxanthine linked by the N9 nitrogen to the C1 carbon of ribose. It is an intermediate in the degradation of purines and purine nucleosides to uric acid and in pathways of purine salvage. It also occurs in the anticodon of certain transfer RNA molecules. (Dorland, 28th ed)
A class of cell surface receptors that prefer ADENOSINE to other endogenous PURINES. Purinergic P1 receptors are widespread in the body including the cardiovascular, respiratory, immune, and nervous systems. There are at least two pharmacologically distinguishable types (A1 and A2, or Ri and Ra).
A subtype of ADENOSINE RECEPTOR that is found expressed in a variety of locations including the BRAIN and endocrine tissues. The receptor is generally considered to be coupled to the GI, INHIBITORY G-PROTEIN which causes down regulation of CYCLIC AMP.
An enzyme which catalyzes the deamination of CYTOSINE resulting in the formation of URACIL. It can also act on 5-methylcytosine to form THYMIDINE.
An enzyme that catalyzes the hydrolytic deamination of deoxycytidylic acid to deoxyuridylic acid and ammonia. It plays an important role in the regulation of the pool of deoxynucleotides in higher organisms. The enzyme also acts on some 5-substituted deoxycytidylic acids. EC 3.5.4.12.
A subclass of adenosine A2 receptors found in the CECUM, the COLON, the BLADDER, and a variety of other tissues. It is generally considered to be a low affinity receptor for ADENOSINE that couples to the GS, STIMULATORY G-PROTEIN.
Nucleosides in which the purine or pyrimidine base is combined with ribose. (Dorland, 28th ed)
An enzyme that catalyzes the deamination of guanine to form xanthine. EC 3.5.4.3.
A subclass of ADENOSINE RECEPTORS that are generally considered to be coupled to the GS, STIMULATORY G-PROTEIN which causes up regulation of CYCLIC AMP.
Purine bases found in body tissues and fluids and in some plants.
Compounds that selectively bind to and block the activation of ADENOSINE A2 RECEPTORS.
Tuberculosis of the serous membrane lining the thoracic cavity and surrounding the lungs.
An antibiotic purine ribonucleoside that readily substitutes for adenosine in the biological system, but its incorporation into DNA and RNA has an inhibitory effect on the metabolism of these nucleic acids.
A glycoprotein enzyme present in various organs and in many cells. The enzyme catalyzes the hydrolysis of a 5'-ribonucleotide to a ribonucleoside and orthophosphate in the presence of water. It is cation-dependent and exists in a membrane-bound and soluble form. EC 3.1.3.5.
Compounds that selectively bind to and activate ADENOSINE A2 RECEPTORS.
Catalyze the hydrolysis of nucleotides with the elimination of ammonia.
Compounds that bind to and block the stimulation of PURINERGIC P1 RECEPTORS.
Compounds that bind to and block the stimulation of ADENOSINE A1 RECEPTORS.
A process that changes the nucleotide sequence of mRNA from that of the DNA template encoding it. Some major classes of RNA editing are as follows: 1, the conversion of cytosine to uracil in mRNA; 2, the addition of variable number of guanines at pre-determined sites; and 3, the addition and deletion of uracils, templated by guide-RNAs (RNA, GUIDE).
Compounds that bind to and stimulate ADENOSINE A1 RECEPTORS.
Compounds that bind to and stimulate PURINERGIC P1 RECEPTORS.
N-Isopropyl-N-phenyl-adenosine. Antilipemic agent. Synonym: TH 162.
An enzyme that catalyzes the reaction between a purine nucleoside and orthophosphate to form a free purine plus ribose-5-phosphate. EC 2.4.2.1.
Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.
Aminohydrolases are a class of enzymes that catalyze the hydrolysis of various nitrogenous compounds, including proteins, nucleotides, and amines, playing a crucial role in numerous biological processes such as metabolism and signaling.
Syndromes in which there is a deficiency or defect in the mechanisms of immunity, either cellular or humoral.
A purine base and a fundamental unit of ADENINE NUCLEOTIDES.
The removal of an amino group (NH2) from a chemical compound.
A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3',5'-CYCLIC NUCLEOTIDE PHOSPHODIESTERASE that degrades CYCLIC AMP thus potentiates the actions of agents that act through ADENYLYL CYCLASES and cyclic AMP.
2-Chloroadenosine. A metabolically stable analog of adenosine which acts as an adenosine receptor agonist. The compound has a potent effect on the peripheral and central nervous system.
Presence of fluid in the pleural cavity resulting from excessive transudation or exudation from the pleural surfaces. It is a sign of disease and not a diagnosis in itself.
A serine protease that catalyses the release of an N-terminal dipeptide. Several biologically-active peptides have been identified as dipeptidyl peptidase 4 substrates including INCRETINS; NEUROPEPTIDES; and CHEMOKINES. The protein is also found bound to ADENOSINE DEAMINASE on the T-CELL surface and is believed to play a role in T-cell activation.
A stable adenosine A1 and A2 receptor agonist. Experimentally, it inhibits cAMP and cGMP phosphodiesterase activity.
Adenine nucleotides which contain deoxyribose as the sugar moiety.
Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human Severe Combined Immunodeficiency (SCID).
Inborn errors of purine-pyrimidine metabolism refer to genetic disorders resulting from defects in the enzymes responsible for the metabolic breakdown and synthesis of purines and pyrimidines, leading to the accumulation of toxic metabolites or deficiency of necessary nucleotides, causing various clinical manifestations such as neurological impairment, kidney problems, and developmental delays.
Cell surface proteins that bind PURINES with high affinity and trigger intracellular changes which influence the behavior of cells. The best characterized classes of purinergic receptors in mammals are the P1 receptors, which prefer ADENOSINE, and the P2 receptors, which prefer ATP or ADP.
A class of enzymes that catalyze the conversion of a nucleotide and water to a nucleoside and orthophosphate. EC 3.1.3.-.
Electrophoresis in which a starch gel (a mixture of amylose and amylopectin) is used as the diffusion medium.
Adenine nucleotides are molecules that consist of an adenine base attached to a ribose sugar and one, two, or three phosphate groups, including adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), which play crucial roles in energy transfer and signaling processes within cells.
An enzyme that catalyzes the tetrapolymerization of the monopyrrole PORPHOBILINOGEN into the hydroxymethylbilane preuroporphyrinogen (UROPORPHYRINOGENS) in several discrete steps. It is the third enzyme in the 8-enzyme biosynthetic pathway of HEME. In humans, deficiency in this enzyme encoded by HMBS (or PBGD) gene results in a form of neurological porphyria (PORPHYRIA, ACUTE INTERMITTENT). This enzyme was formerly listed as EC 4.3.1.8
An enzyme which catalyzes the catabolism of S-ADENOSYLHOMOCYSTEINE to ADENOSINE and HOMOCYSTEINE. It may play a role in regulating the concentration of intracellular adenosylhomocysteine.
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
A purine and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.
Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.
A group of compounds that are derivatives of beta- aminoethylbenzene which is structurally and pharmacologically related to amphetamine. (From Merck Index, 11th ed)
The rate dynamics in chemical or physical systems.
Analyses for a specific enzyme activity, or of the level of a specific enzyme that is used to assess health and disease risk, for early detection of disease or disease prediction, diagnosis, and change in disease status.
Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
Enzymes that catalyze the cleavage of a carbon-carbon bond by means other than hydrolysis or oxidation. This subclass contains the DECARBOXYLASES, the ALDEHYDE-LYASES, and the OXO-ACID-LYASES. EC 4.1.
Purines with a RIBOSE attached that can be phosphorylated to PURINE NUCLEOTIDES.
Leukemia associated with HYPERPLASIA of the lymphoid tissues and increased numbers of circulating malignant LYMPHOCYTES and lymphoblasts.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Compounds that selectively bind to and block the activation of ADENOSINE A3 RECEPTORS.
A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752)
INFLAMMATION of the sac surrounding the heart (PERICARDIUM) due to MYCOBACTERIUM TUBERCULOSIS infection. Pericarditis can lead to swelling (PERICARDIAL EFFUSION), compression of the heart (CARDIAC TAMPONADE), and preventing normal beating of the heart.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
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.
Sulfhydryl analog of INOSINE that inhibits nucleoside transport across erythrocyte plasma membranes, and has immunosuppressive properties. It has been used similarly to MERCAPTOPURINE in the treatment of leukemia. (From Martindale, The Extra Pharmacopoeia, 30th ed, p503)
A pyridoxal-phosphate protein that catalyzes the deamination of THREONINE to 2-ketobutyrate and AMMONIA. The role of this enzyme can be biosynthetic or biodegradative. In the former role it supplies 2-ketobutyrate required for ISOLEUCINE biosynthesis, while in the latter it is only involved in the breakdown of threonine to supply energy. This enzyme was formerly listed as EC 4.2.1.16.
Established cell cultures that have the potential to propagate indefinitely.
Drugs that selectively bind to and activate ADENOSINE A3 RECEPTORS.
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.
A form of PERITONITIS seen in patients with TUBERCULOSIS, characterized by lesion either as a miliary form or as a pelvic mass on the peritoneal surfaces. Most patients have ASCITES, abdominal swelling, ABDOMINAL PAIN, and other systemic symptoms such as FEVER; WEIGHT LOSS; and ANEMIA.
A fluorinated cytosine analog that is used as an antifungal agent.
A purine or pyrimidine base bonded to DEOXYRIBOSE.
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by a hydrogen. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is an inhibitor of HIV replication, acting as a chain-terminator of viral DNA by binding to reverse transcriptase. Its principal side effect is nephrotoxicity. In vivo, dideoxyadenosine is rapidly metabolized to DIDANOSINE (ddI) by enzymatic deamination; ddI is then converted to dideoxyinosine monophosphate and ultimately to dideoxyadenosine triphosphate, the putative active metabolite.
Pyrazolopyrimidine ribonucleosides isolated from Nocardia interforma. They are antineoplastic antibiotics with cytostatic properties.
A nucleoside antibiotic isolated from Streptomyces antibioticus. It has some antineoplastic properties and has broad spectrum activity against DNA viruses in cell cultures and significant antiviral activity against infections caused by a variety of viruses such as the herpes viruses, the VACCINIA VIRUS and varicella zoster virus.
5'-S-(3-Amino-3-carboxypropyl)-5'-thioadenosine. Formed from S-adenosylmethionine after transmethylation reactions.
White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.
Inosine 5'-Monophosphate. A purine nucleotide which has hypoxanthine as the base and one phosphate group esterified to the sugar moiety.
Drugs that bind to and block the activation of PURINERGIC RECEPTORS.
An inhibitor of nucleotide metabolism.
RNA consisting of two strands as opposed to the more prevalent single-stranded RNA. Most of the double-stranded segments are formed from transcription of DNA by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop. Some double-stranded segments of RNA are normal in all organisms.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Pigmentation disorders are conditions that affect the production or distribution of melanin, the pigment responsible for skin, hair, and eye color, leading to changes in the color of these bodily features.
A programmed mutation process whereby changes are introduced to the nucleotide sequence of immunoglobulin gene DNA during development.
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 category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
A purine nucleoside that has guanine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid and its nucleotides play important roles in metabolism. (From Dorland, 28th ed)
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
LIPOLYSIS of stored LIPIDS in the ADIPOSE TISSUE to release FREE FATTY ACIDS. Mobilization of stored lipids is under the regulation of lipolytic signals (CATECHOLAMINES) or anti-lipolytic signals (INSULIN) via their actions on the hormone-sensitive LIPASE. This concept does not include lipid transport.
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.
Heterocyclic rings containing three nitrogen atoms, commonly in 1,2,4 or 1,3,5 or 2,4,6 formats. Some are used as HERBICIDES.
Gene rearrangement of the B-lymphocyte which results in a substitution in the type of heavy-chain constant region that is expressed. This allows the effector response to change while the antigen binding specificity (variable region) remains the same. The majority of class switching occurs by a DNA recombination event but it also can take place at the level of RNA processing.
Enzymes that catalyze the formation of a carbon-carbon double bond by the elimination of AMMONIA. EC 4.3.1.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
An enzyme that catalyzes reversibly the phosphorylation of deoxycytidine with the formation of a nucleoside diphosphate and deoxycytidine monophosphate. Cytosine arabinoside can also act as an acceptor. All natural nucleoside triphosphates, except deoxycytidine triphosphate, can act as donors. The enzyme is induced by some viruses, particularly the herpes simplex virus (HERPESVIRUS HOMINIS). EC 2.7.1.74.
A calcium-activated enzyme that catalyzes the hydrolysis of ATP to yield AMP and orthophosphate. It can also act on ADP and other nucleoside triphosphates and diphosphates. EC 3.6.1.5.
A PYRIDOXAL-phosphate containing enzyme that catalyzes the dehydration and deamination of L-serine to form pyruvate. This enzyme was formerly listed as EC 4.2.1.13.
A non-template-directed DNA polymerase normally found in vertebrate thymus and bone marrow. It catalyzes the elongation of oligo- or polydeoxynucleotide chains and is widely used as a tool in the differential diagnosis of acute leukemias in man. EC 2.7.7.31.
Proteins involved in the transport of NUCLEOSIDES across cellular membranes.
The metabolic process of breaking down LIPIDS to release FREE FATTY ACIDS, the major oxidative fuel for the body. Lipolysis may involve dietary lipids in the DIGESTIVE TRACT, circulating lipids in the BLOOD, and stored lipids in the ADIPOSE TISSUE or the LIVER. A number of enzymes are involved in such lipid hydrolysis, such as LIPASE and LIPOPROTEIN LIPASE from various tissues.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.
Any member of the class of enzymes that catalyze the cleavage of the substrate and the addition of water to the resulting molecules, e.g., ESTERASES, glycosidases (GLYCOSIDE HYDROLASES), lipases, NUCLEOTIDASES, peptidases (PEPTIDE HYDROLASES), and phosphatases (PHOSPHORIC MONOESTER HYDROLASES). EC 3.
Family of RNA viruses that infects birds and mammals and encodes the enzyme reverse transcriptase. The family contains seven genera: DELTARETROVIRUS; LENTIVIRUS; RETROVIRUSES TYPE B, MAMMALIAN; ALPHARETROVIRUS; GAMMARETROVIRUS; RETROVIRUSES TYPE D; and SPUMAVIRUS. A key feature of retrovirus biology is the synthesis of a DNA copy of the genome which is integrated into cellular DNA. After integration it is sometimes not expressed but maintained in a latent state (PROVIRUSES).

The RNA-editing enzyme ADAR1 is localized to the nascent ribonucleoprotein matrix on Xenopus lampbrush chromosomes but specifically associates with an atypical loop. (1/1316)

Double-stranded RNA adenosine deaminase (ADAR1, dsRAD, DRADA) converts adenosines to inosines in double-stranded RNAs. Few candidate substrates for ADAR1 editing are known at this point and it is not known how substrate recognition is achieved. In some cases editing sites are defined by basepaired regions formed between intronic and exonic sequences, suggesting that the enzyme might function cotranscriptionally. We have isolated two variants of Xenopus laevis ADAR1 for which no editing substrates are currently known. We demonstrate that both variants of the enzyme are associated with transcriptionally active chromosome loops suggesting that the enzyme acts cotranscriptionally. The widespread distribution of the protein along the entire chromosome indicates that ADAR1 associates with the RNP matrix in a substrate-independent manner. Inhibition of splicing, another cotranscriptional process, does not affect the chromosomal localization of ADAR1. Furthermore, we can show that the enzyme is dramatically enriched on a special RNA-containing loop that seems transcriptionally silent. Detailed analysis of this loop suggests that it might represent a site of ADAR1 storage or a site where active RNA editing is taking place. Finally, mutational analysis of ADAR1 demonstrates that a putative Z-DNA binding domain present in ADAR1 is not required for chromosomal targeting of the protein.  (+info)

The extracellular versus intracellular mechanisms of inhibition of TCR-triggered activation in thymocytes by adenosine under conditions of inhibited adenosine deaminase. (2/1316)

The absence or low levels of adenosine deaminase (ADA) in humans result in severe combined immunodeficiency (SCID), which is characterized by hypoplastic thymus, T lymphocyte depletion and autoimmunity. Deficiency of ADA causes increased levels of both intracellular and extracellular adenosine, although only the intracellular lymphotoxicity of accumulated adenosine is considered in the pathogenesis of ADA SCID. It is shown that extracellular but not intracellular adenosine selectively inhibits TCR-triggered up-regulation of activation markers and apoptotic events in thymocytes under conditions of ADA deficiency. The effects of intracellular adenosine are dissociated from effects of extracellular adenosine in experiments using an adenosine transporter blocker. We found that prevention of toxicity of intracellular adenosine led to survival of TCR-cross-linked thymocytes in long-term (4 days) assays, but it was not sufficient for normal T cell differentiation under conditions of inhibited ADA. Surviving TCR-cross-linked thymocytes had a non-activated phenotype due to extracellular adenosine-mediated, TCR-antagonizing signaling. Taken together the data suggest that both intracellular toxicity and signaling by extracellular adenosine may contribute to pathogenesis of ADA SCID. Accordingly, extracellular adenosine may act on thymocytes, which survived intracellular toxicity of adenosine during ADA deficiency by counteracting TCR signaling. This, in turn, could lead to failure of positive and negative selection of thymocytes, and to additional elimination of thymocytes or autoimmunity of surviving T cells.  (+info)

Nucleotide pool imbalance and adenosine deaminase deficiency induce alterations of N-region insertions during V(D)J recombination. (3/1316)

Template-independent nucleotide additions (N regions) generated at sites of V(D)J recombination by terminal deoxynucleotidyl transferase (TdT) increase the diversity of antigen receptors. Two inborn errors of purine metabolism, deficiencies of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP), result in defective lymphoid development and aberrant pools of 2'-deoxynucleotides that are substrates for TdT in lymphoid precursors. We have asked whether selective increases in dATP or dGTP pools result in altered N regions in an extrachromosomal substrate transfected into T-cell or pre-B-cell lines. Exposure of the transfected cells to 2'-deoxyadenosine and an ADA inhibitor increased the dATP pool and resulted in a marked increase in A-T insertions at recombination junctions, with an overall decreased frequency of V(D)J recombination. Sequence analysis of VH-DH-JH junctions from the IgM locus in B-cell lines from ADA-deficient patients demonstrated an increase in A-T insertions equivalent to that found in the transfected cells. In contrast, elevation of dGTP pools, as would occur in PNP deficiency, did not alter the already rich G-C content of N regions. We conclude that the frequency of V(D)J recombination and the composition of N-insertions are influenced by increases in dATP levels, potentially leading to alterations in antigen receptors and aberrant lymphoid development. Alterations in N-region insertions may contribute to the B-cell dysfunction associated with ADA deficiency.  (+info)

A study of the genetical structure of the Cuban population: red cell and serum biochemical markers. (4/1316)

Gene frequencies of several red cell and serum gentic markers were determined in the three main racial groups--whites, mulattoes and Negroes--of the Cuban population. The results were used to estimate the relative contribution of Caucasian and Negro genes to the genetic makeup of these three groups and to calculate the frequencies of these genes in the general Cuban population.  (+info)

Adenosine deaminase activity in thymus and other human tissues. (5/1316)

Adenosine deaminase activity (ADA) has been estimated in human tissues. Levels in the thymus during childhood were very much higher than in any of the other 6 tissues studied. Intermediate activities were obtained from spleen and lymph nodes and also skin. Cerebral cortex, liver and kidney had relatively low levels. ADA activity in lymphocytes from peripheral blood was significantly increased after antigenic stimulation by TAB immunization. The available evidence appears to be consistent with T-lymphocyte growth and development in the thymus being dependant on ADA.  (+info)

Regulation of forestomach-specific expression of the murine adenosine deaminase gene. (6/1316)

The maturation of stratified squamous epithelium of the upper gastrointestinal tract is a highly ordered process of development and differentiation. Information on the molecular basis of this process is, however, limited. Here we report the identification of the first murine forestomach regulatory element using the murine adenosine deaminase (Ada) gene as a model. In the adult mouse, Ada is highly expressed in the terminally differentiated epithelial layer of upper gastrointestinal tract tissues. The data reported here represent the identification and detailed analysis of a 1. 1-kilobase (kb) sequence located 3.4-kb upstream of the transcription initiation site of the murine Ada gene, which is sufficient to target cat reporter gene expression to the forestomach in transgenic mice. This 1.1-kb fragment is capable of directing cat reporter gene expression mainly to the forestomach of transgenic mice, with a level comparable to the endogenous Ada gene. This expression is localized to the appropriate cell types, confers copy number dependence, and shows the same developmental regulation. Mutational analysis revealed the functional importance of multiple transcription factor-binding sites.  (+info)

Human RNA-specific adenosine deaminase ADAR1 transcripts possess alternative exon 1 structures that initiate from different promoters, one constitutively active and the other interferon inducible. (7/1316)

RNA-specific adenosine deaminase (ADAR1) catalyzes the deamination of adenosine to inosine in viral and cellular RNAs. Two size forms of the ADAR1 editing enzyme are known, an IFN-inducible approximately 150-kDa protein and a constitutively expressed N-terminally truncated approximately 110-kDa protein. We have now identified alternative exon 1 structures of human ADAR1 transcripts that initiate from unique promoters, one constitutively expressed and the other IFN inducible. Cloning and sequence analyses of 5'-rapid amplification of cDNA ends (RACE) cDNAs from human placenta established a linkage between exon 2 of ADAR1 and two alternative exon 1 structures, designated herein as exon 1A and exon 1B. Analysis of RNA isolated from untreated and IFN-treated human amnion cells demonstrated that exon 1B-exon 2 transcripts were synthesized in the absence of IFN and were not significantly altered in amount by IFN treatment. By contrast, exon 1A-exon 2 transcripts were IFN inducible. Transient transfection analysis with reporter constructs led to the identification of two functional promoters, designated PC and PI. Exon 1B transcripts were initiated from the PC promoter whose activity in transient transfection reporter assays was not increased by IFN treatment. The 107-nt exon 1B mapped 14.5 kb upstream of exon 2. The 201-nt exon 1A that mapped 5.4 kb upstream of exon 2 was initiated from the interferon-inducible PI promoter. These results suggest that two promoters, one IFN inducible and the other not, initiate transcription of the ADAR1 gene, and that alternative splicing of unique exon 1 structures to a common exon 2 junction generates RNA transcripts with the deduced coding capacity for either the constitutively expressed approximately 110-kDa ADAR1 protein (exon 1B) or the interferon-induced approximately 150-kDa ADAR1 protein (exon 1A).  (+info)

Long RNA hairpins that contain inosine are present in Caenorhabditis elegans poly(A)+ RNA. (8/1316)

Adenosine deaminases that act on RNA (ADARs) are RNA-editing enzymes that convert adenosine to inosine within double-stranded RNA. In the 12 years since the discovery of ADARs only a few natural substrates have been identified. These substrates were found by chance, when genomically encoded adenosines were identified as guanosines in cDNAs. To advance our understanding of the biological roles of ADARs, we developed a method for systematically identifying ADAR substrates. In our first application of the method, we identified five additional substrates in Caenorhabditis elegans. Four of those substrates are mRNAs edited in untranslated regions, and one is a noncoding RNA edited throughout its length. The edited regions are predicted to form long hairpin structures, and one of the RNAs encodes POP-1, a protein involved in cell fate decisions.  (+info)

Adenosine Deaminase (ADA) is an enzyme that plays a crucial role in the immune system by helping to regulate the levels of certain chemicals called purines within cells. Specifically, ADA helps to break down adenosine, a type of purine, into another compound called inosine. This enzyme is found in all tissues of the body, but it is especially active in the immune system's white blood cells, where it helps to support their growth, development, and function.

ADA deficiency is a rare genetic disorder that can lead to severe combined immunodeficiency (SCID), a condition in which babies are born with little or no functional immune system. This makes them extremely vulnerable to infections, which can be life-threatening. ADA deficiency can be treated with enzyme replacement therapy, bone marrow transplantation, or gene therapy.

Adenosine deaminase inhibitors are a class of medications that work by blocking the action of the enzyme adenosine deaminase. This enzyme is responsible for breaking down adenosine, a chemical in the body that helps regulate the immune system and is involved in the inflammatory response.

By inhibiting the activity of adenosine deaminase, these medications can increase the levels of adenosine in the body. This can be useful in certain medical conditions where reducing inflammation is important. For example, adenosine deaminase inhibitors are sometimes used to treat rheumatoid arthritis, a chronic autoimmune disease characterized by inflammation and damage to the joints.

One common adenosine deaminase inhibitor is called deoxycoformycin (also known as pentostatin). This medication is typically given intravenously and is used to treat hairy cell leukemia, a rare type of cancer that affects white blood cells.

It's important to note that adenosine deaminase inhibitors can have serious side effects, including suppression of the immune system, which can make people more susceptible to infections. They should only be used under the close supervision of a healthcare provider.

Adenosine is a purine nucleoside that is composed of a sugar (ribose) and the base adenine. It plays several important roles in the body, including serving as a precursor for the synthesis of other molecules such as ATP, NAD+, and RNA.

In the medical context, adenosine is perhaps best known for its use as a pharmaceutical agent to treat certain cardiac arrhythmias. When administered intravenously, it can help restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT) by slowing conduction through the atrioventricular node and interrupting the reentry circuit responsible for the arrhythmia.

Adenosine can also be used as a diagnostic tool to help differentiate between narrow-complex tachycardias of supraventricular origin and those that originate from below the ventricles (such as ventricular tachycardia). This is because adenosine will typically terminate PSVT but not affect the rhythm of VT.

It's worth noting that adenosine has a very short half-life, lasting only a few seconds in the bloodstream. This means that its effects are rapidly reversible and generally well-tolerated, although some patients may experience transient symptoms such as flushing, chest pain, or shortness of breath.

Nucleoside deaminases are a group of enzymes that catalyze the removal of an amino group (-NH2) from nucleosides, converting them to nucleosides with a modified base. This modification process is called deamination. Specifically, these enzymes convert cytidine and adenosine to uridine and inosine, respectively. Nucleoside deaminases play crucial roles in various biological processes, including the regulation of gene expression, immune response, and nucleic acid metabolism. Some nucleoside deaminases are also involved in the development of certain diseases and are considered as targets for drug design and discovery.

Coformycin is an antimetabolite antibiotic, which means it interferes with the growth of bacteria by inhibiting the synthesis of nucleic acids, the genetic material of bacteria. It is derived from Streptomyces coelicolor and is used primarily in research to study bacterial metabolism.

Coformycin is a potent inhibitor of bacterial enzyme adenosine deaminase, which is involved in purine biosynthesis. By inhibiting this enzyme, Coformycin prevents the bacteria from synthesizing the building blocks needed to make DNA and RNA, thereby inhibiting their growth.

Coformycin has not been approved for use as a therapeutic drug in humans or animals due to its narrow spectrum of activity and potential toxicity. However, it is still used in research settings to study bacterial metabolism and the mechanisms of antibiotic resistance.

AMP deaminase is an enzyme that is responsible for the conversion of adenosine monophosphate (AMP) to inosine monophosphate (IMP), which is a part of the purine nucleotide cycle. This enzyme plays a crucial role in energy metabolism, particularly in muscles during exercise. A deficiency in AMP deaminase has been linked to muscle fatigue and weakness.

Pentostatin is a medication used in the treatment of certain types of cancer, including hairy cell leukemia and certain T-cell lymphomas. It is a type of drug called a purine nucleoside analog, which works by interfering with the production of DNA and RNA, the genetic material found in cells. This can help to stop the growth and multiplication of cancer cells.

Pentostatin is given intravenously (through an IV) in a healthcare setting, such as a hospital or clinic. It is usually administered on a schedule of every other week. Common side effects of pentostatin include nausea, vomiting, diarrhea, and loss of appetite. It can also cause more serious side effects, such as low blood cell counts, infections, and liver problems.

It's important to note that this is a medical definition of the drug and its use, and it should not be used as a substitute for professional medical advice. If you have any questions about pentostatin or your treatment, it is best to speak with your healthcare provider.

Adenosine A2A receptor is a type of G protein-coupled receptor that binds to the endogenous purine nucleoside, adenosine. It is a subtype of the A2 receptor along with the A2B receptor and is widely distributed throughout the body, particularly in the brain, heart, and immune system.

The A2A receptor plays an essential role in various physiological processes, including modulation of neurotransmission, cardiovascular function, and immune response. In the brain, activation of A2A receptors can have both excitatory and inhibitory effects on neuronal activity, depending on the location and context.

In the heart, A2A receptor activation has a negative chronotropic effect, reducing heart rate, and a negative inotropic effect, decreasing contractility. In the immune system, A2A receptors are involved in regulating inflammation and immune cell function.

Pharmacologically, A2A receptor agonists have been investigated for their potential therapeutic benefits in various conditions, including Parkinson's disease, chronic pain, ischemia-reperfusion injury, and cancer. Conversely, A2A receptor antagonists have also been studied as a potential treatment for neurodegenerative disorders, such as Alzheimer's disease, and addiction.

Adenosine kinase (ADK) is an enzyme that plays a crucial role in the regulation of adenosine levels in cells. The medical definition of adenosine kinase is:

"An enzyme (EC 2.7.1.20) that catalyzes the phosphorylation of adenosine to form adenosine monophosphate (AMP) using ATP as the phosphate donor. This reaction helps maintain the balance between adenosine and its corresponding nucleotides in cells, and it plays a significant role in purine metabolism, cell signaling, and energy homeostasis."

Adenosine kinase is widely distributed in various tissues, including the brain, heart, liver, and muscles. Dysregulation of adenosine kinase activity has been implicated in several pathological conditions, such as ischemia-reperfusion injury, neurodegenerative disorders, and cancer. Therefore, modulating adenosine kinase activity has emerged as a potential therapeutic strategy for treating these diseases.

Adenosine A1 receptor is a type of G protein-coupled receptor that binds to the endogenous purine nucleoside adenosine. When activated, it inhibits the production of cyclic AMP (cAMP) in the cell by inhibiting adenylyl cyclase activity. This results in various physiological effects, such as decreased heart rate and reduced force of heart contractions, increased potassium conductance, and decreased calcium currents. The Adenosine A1 receptor is widely distributed throughout the body, including the brain, heart, kidneys, and other organs. It plays a crucial role in various biological processes, including cardiovascular function, neuroprotection, and inflammation.

Cytidine deaminase is an enzyme that catalyzes the removal of an amino group from cytidine, converting it to uridine. This reaction is part of the process of RNA degradation and also plays a role in the immune response to viral infections.

Cytidine deaminase can be found in various organisms, including bacteria, humans, and other mammals. In humans, cytidine deaminase is encoded by the APOBEC3 gene family, which consists of several different enzymes that have distinct functions and expression patterns. Some members of this gene family are involved in the restriction of retroviruses, such as HIV-1, while others play a role in the regulation of endogenous retroelements and the modification of cellular RNA.

Mutations in cytidine deaminase genes have been associated with various diseases, including cancer and autoimmune disorders. For example, mutations in the APOBEC3B gene have been linked to an increased risk of breast cancer, while mutations in other members of the APOBEC3 family have been implicated in the development of lymphoma and other malignancies. Additionally, aberrant expression of cytidine deaminase enzymes has been observed in some autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, suggesting a potential role for these enzymes in the pathogenesis of these conditions.

Deoxyadenosine is a chemical compound that is a component of DNA, one of the nucleic acids that make up the genetic material of living organisms. Specifically, deoxyadenosine is a nucleoside, which is a molecule consisting of a sugar (in this case, deoxyribose) bonded to a nitrogenous base (in this case, adenine).

Deoxyribonucleosides like deoxyadenosine are the building blocks of DNA, along with phosphate groups. In DNA, deoxyadenosine pairs with thymidine via hydrogen bonds to form one of the four rungs in the twisted ladder structure of the double helix.

It is important to note that there is a similar compound called adenosine, which contains an extra oxygen atom on the sugar molecule (making it a ribonucleoside) and is a component of RNA, another nucleic acid involved in protein synthesis and other cellular processes.

Inosine is not a medical condition but a naturally occurring compound called a nucleoside, which is formed from the combination of hypoxanthine and ribose. It is an intermediate in the metabolic pathways of purine nucleotides, which are essential components of DNA and RNA. Inosine has been studied for its potential therapeutic benefits in various medical conditions, including neurodegenerative disorders, cardiovascular diseases, and cancer. However, more research is needed to fully understand its mechanisms and clinical applications.

Purinergic P1 receptors are a type of G-protein coupled receptor that bind to nucleotides such as adenosine. These receptors are involved in a variety of physiological processes, including modulation of neurotransmitter release, cardiovascular function, and immune response. There are four subtypes of P1 receptors (A1, A2A, A2B, and A3) that have different signaling pathways and functions. Activation of these receptors can lead to a variety of cellular responses, including inhibition or stimulation of adenylyl cyclase activity, changes in intracellular calcium levels, and activation of various protein kinases. They play important roles in the central nervous system, cardiovascular system, respiratory system, gastrointestinal system, and immune system.

Adenosine A3 receptor (A3R) is a type of G-protein coupled receptor that binds to adenosine, a purine nucleoside, and plays a role in various physiological processes. The activation of A3R leads to the inhibition of adenylate cyclase activity, which results in decreased levels of intracellular cAMP. This, in turn, modulates several downstream signaling pathways that are involved in anti-inflammatory and neuroprotective effects.

A3R is widely expressed in various tissues, including the brain, heart, lungs, liver, kidneys, and immune cells. In the central nervous system, A3R activation has been shown to have neuroprotective effects, such as reducing glutamate release, protecting against excitotoxicity, and modulating neuroinflammation. Additionally, A3R agonists have been investigated for their potential therapeutic benefits in various pathological conditions, including pain management, ischemia-reperfusion injury, and neurodegenerative diseases.

Overall, the Adenosine A3 receptor is an important target for drug development due to its role in modulating inflammation and cellular responses in various tissues and diseases.

Cytosine deaminase is an enzyme that catalyzes the hydrolytic deamination of cytosine residues in DNA or deoxycytidine residues in RNA, converting them to uracil or uridine, respectively. This enzyme plays a role in the regulation of gene expression and is also involved in the defense against viral infections in some organisms. In humans, cytosine deamination in DNA can lead to mutations and has been implicated in the development of certain diseases, including cancer.

DCMP deaminase is an enzyme that catalyzes the deamination of deoxycytidine monophosphate (dCMP) to deoxyuridine monophosphate (dUMP). This reaction is a part of the pyrimidine nucleotide biosynthesis pathway. The enzyme's systematic name is "deoxycytidine monophosphate deaminase." It plays a crucial role in DNA synthesis and maintenance by providing the necessary precursor (dUMP) for thymidylate synthesis, which is essential for the production of thymidine triphosphate (dTTP), one of the four building blocks of DNA.

Adenosine A2B receptor (A2BAR) is a type of G protein-coupled receptor that binds the endogenous purine nucleoside adenosine. It is a subtype of the A2 class of adenosine receptors, which also includes A2A receptor.

The A2BAR is widely expressed in various tissues and cells, including vascular smooth muscle cells, endothelial cells, fibroblasts, immune cells, and epithelial cells. Activation of the A2BAR by adenosine leads to a variety of cellular responses, such as relaxation of vascular smooth muscle, inhibition of platelet aggregation, modulation of inflammatory responses, and stimulation of fibroblast proliferation and collagen production.

The A2BAR has been implicated in several physiological and pathophysiological processes, such as cardiovascular function, pain perception, neuroprotection, tumor growth and metastasis, and pulmonary fibrosis. Therefore, the development of selective A2BAR agonists or antagonists has been an area of active research for therapeutic interventions in these conditions.

Ribonucleosides are organic compounds that consist of a nucleoside bound to a ribose sugar. Nucleosides are formed when a nitrogenous base (such as adenine, guanine, uracil, cytosine, or thymine) is attached to a sugar molecule (either ribose or deoxyribose) via a beta-glycosidic bond. In the case of ribonucleosides, the sugar component is D-ribose. Ribonucleosides play important roles in various biological processes, particularly in the storage, transfer, and expression of genetic information within cells. When ribonucleosides are phosphorylated, they become the building blocks of RNA (ribonucleic acid), a crucial biomolecule involved in protein synthesis and other cellular functions. Examples of ribonucleosides include adenosine, guanosine, uridine, cytidine, and inosine.

Guanine Deaminase is an enzyme that catalyzes the chemical reaction in which guanine, one of the four nucleotides that make up DNA and RNA, is deaminated to form xanthine. This reaction is part of the purine catabolism pathway, which is the breakdown of purines to produce energy and eliminate nitrogenous waste. The gene that encodes this enzyme in humans is located on chromosome 2 and is called GDA. Deficiency in guanine deaminase has been associated with Lesch-Nyhan syndrome, a rare genetic disorder characterized by mental retardation, self-mutilation, spasticity, and uric acid overproduction.

Adenosine A2 receptors are a type of G-protein coupled receptor that binds the endogenous purine nucleoside adenosine. They are divided into two subtypes, A2a and A2b, which have different distributions in the body and couple to different G proteins.

A2a receptors are found in high levels in the brain, particularly in the striatum, and play a role in regulating the release of neurotransmitters such as dopamine and glutamate. They also have anti-inflammatory effects and are being studied as potential targets for the treatment of neurological disorders such as Parkinson's disease and multiple sclerosis.

A2b receptors, on the other hand, are found in a variety of tissues including the lung, blood vessels, and immune cells. They play a role in regulating inflammation and vasodilation, and have been implicated in the development of conditions such as asthma and pulmonary fibrosis.

Both A2a and A2b receptors are activated by adenosine, which is released in response to cellular stress or injury. Activation of these receptors can lead to a variety of downstream effects, depending on the tissue and context in which they are expressed.

Xanthines are a type of natural alkaloids that are found in various plants, including tea leaves, cocoa beans, and mate. The most common xanthines are caffeine, theophylline, and theobromine. These compounds have stimulant effects on the central nervous system and are often used in medication to treat conditions such as asthma, bronchitis, and other respiratory issues.

Caffeine is the most widely consumed xanthine and is found in a variety of beverages like coffee, tea, and energy drinks. It works by blocking adenosine receptors in the brain, which can lead to increased alertness and reduced feelings of fatigue.

Theophylline is another xanthine that is used as a bronchodilator to treat asthma and other respiratory conditions. It works by relaxing smooth muscles in the airways, making it easier to breathe.

Theobromine is found in cocoa beans and is responsible for the stimulant effects of chocolate. While it has similar properties to caffeine and theophylline, it is less potent and has a milder effect on the body.

It's worth noting that while xanthines can have beneficial effects when used in moderation, they can also cause negative side effects such as insomnia, nervousness, and rapid heart rate if consumed in large quantities or over an extended period of time.

Adenosine A2 receptor antagonists are a class of pharmaceutical compounds that block the action of adenosine at A2 receptors. Adenosine is a naturally occurring molecule in the body that acts as a neurotransmitter and has various physiological effects, including vasodilation and inhibition of heart rate.

Adenosine A2 receptor antagonists work by binding to A2 receptors and preventing adenosine from activating them. This results in the opposite effect of adenosine, leading to vasoconstriction and increased heart rate. These drugs are used for a variety of medical conditions, including asthma, chronic obstructive pulmonary disease (COPD), and heart failure.

Examples of Adenosine A2 receptor antagonists include theophylline, caffeine, and some newer drugs such asistradefylline and tozadenant. These drugs have different pharmacological properties and are used for specific medical conditions. It is important to note that adenosine A2 receptor antagonists can have side effects, including restlessness, insomnia, and gastrointestinal symptoms, and should be used under the guidance of a healthcare professional.

Pleural Tuberculosis is a form of extrapulmonary tuberculosis (EPTB) that involves the infection and inflammation of the pleura, which are the thin membranes that surround the lungs and line the inside of the chest cavity. This condition is caused by the Mycobacterium tuberculosis bacterium, which can spread through the air when an infected person coughs, sneezes, or talks.

In pleural tuberculosis, the bacteria reach the pleura either through direct extension from a nearby lung infection or via bloodstream dissemination. The infection can cause the pleura to become inflamed and produce excess fluid, leading to pleural effusion. This accumulation of fluid in the pleural space can cause chest pain, coughing, and difficulty breathing.

Diagnosis of pleural tuberculosis typically involves a combination of medical history, physical examination, imaging studies such as chest X-rays or CT scans, and laboratory tests such as acid-fast bacilli (AFB) smear microscopy, culture, and nucleic acid amplification tests (NAATs) to detect the presence of M. tuberculosis in the pleural fluid or tissue samples.

Treatment of pleural tuberculosis typically involves a standard course of anti-tuberculosis therapy (ATT), which includes a combination of multiple antibiotics such as isoniazid, rifampin, ethambutol, and pyrazinamide. The duration of treatment may vary depending on the severity of the infection and the patient's response to therapy. In some cases, surgical intervention may be necessary to drain the pleural effusion or remove the infected pleura.

Tubercidin is not a medical term itself, but it is a type of antibiotic that belongs to the class of compounds known as nucleoside antibiotics. Specifically, tubercidin is a naturally occurring adenine analogue that is produced by several species of Streptomyces bacteria.

Tubercidin has been found to have antimicrobial and antitumor activities. It works by inhibiting the enzyme adenosine deaminase, which plays a crucial role in the metabolism of nucleotides in cells. By inhibiting this enzyme, tubercidin can interfere with DNA and RNA synthesis, leading to cell death.

While tubercidin has shown promise as an anticancer agent in preclinical studies, its clinical use is limited due to its toxicity and potential for causing mutations in normal cells. Therefore, it is primarily used for research purposes to study the mechanisms of nucleotide metabolism and the effects of nucleoside analogues on cell growth and differentiation.

5'-Nucleotidase is an enzyme that is found on the outer surface of cell membranes, including those of liver cells and red blood cells. Its primary function is to catalyze the hydrolysis of nucleoside monophosphates, such as adenosine monophosphate (AMP) and guanosine monophosphate (GMP), to their corresponding nucleosides, such as adenosine and guanosine, by removing a phosphate group from the 5' position of the nucleotide.

Abnormal levels of 5'-Nucleotidase in the blood can be indicative of liver or bone disease. For example, elevated levels of this enzyme in the blood may suggest liver damage or injury, such as that caused by hepatitis, cirrhosis, or alcohol abuse. Conversely, low levels of 5'-Nucleotidase may be associated with certain types of anemia, including aplastic anemia and paroxysmal nocturnal hemoglobinuria.

Medical professionals may order a 5'-Nucleotidase test to help diagnose or monitor the progression of these conditions. It is important to note that other factors, such as medication use or muscle damage, can also affect 5'-Nucleotidase levels, so results must be interpreted in conjunction with other clinical findings and diagnostic tests.

Adenosine A2 receptor agonists are pharmaceutical agents that bind to and activate the A2 subtype of adenosine receptors, which are G-protein coupled receptors found in various tissues throughout the body. Activation of these receptors leads to a variety of physiological effects, including vasodilation, increased coronary blood flow, and inhibition of platelet aggregation.

A2 receptor agonists have been studied for their potential therapeutic benefits in several medical conditions, such as:

1. Heart failure: A2 receptor agonists can improve cardiac function and reduce symptoms in patients with heart failure by increasing coronary blood flow and reducing oxygen demand.
2. Atrial fibrillation: These agents have been shown to terminate or prevent atrial fibrillation, a common abnormal heart rhythm disorder, through their effects on the electrical properties of cardiac cells.
3. Asthma and COPD: A2 receptor agonists can help relax airway smooth muscle and reduce inflammation in patients with asthma and chronic obstructive pulmonary disease (COPD).
4. Pain management: Some A2 receptor agonists have been found to have analgesic properties, making them potential candidates for pain relief in various clinical settings.

Examples of A2 receptor agonists include regadenoson, which is used as a pharmacological stress agent during myocardial perfusion imaging, and dipyridamole, which is used to prevent blood clots in patients with certain heart conditions. However, it's important to note that these agents can have side effects, such as hypotension, bradycardia, and bronchoconstriction, so their use must be carefully monitored and managed by healthcare professionals.

Nucleotide deaminases are a group of enzymes that catalyze the removal of an amino group (-NH2) from nucleotides, which are the building blocks of DNA and RNA. Specifically, these enzymes convert cytidine or adenosine to uridine or inosine, respectively, by removing an amino group from the corresponding nitrogenous base (cytosine or adenine).

There are several types of nucleotide deaminases that differ in their substrate specificity and cellular localization. For example, some enzymes deaminate DNA or RNA directly, while others act on free nucleotides or nucleosides. Nucleotide deaminases play important roles in various biological processes, including the regulation of gene expression, immune response, and DNA repair.

Abnormal activity or mutations in nucleotide deaminases have been associated with several human diseases, such as cancer, autoimmune disorders, and viral infections. Therefore, understanding the function and regulation of these enzymes is crucial for developing new therapeutic strategies to treat these conditions.

Purinergic P1 receptor antagonists are a class of pharmaceutical drugs that block the activity of purinergic P1 receptors, which are a type of G-protein coupled receptor found in many tissues throughout the body. These receptors are activated by extracellular nucleotides such as adenosine and ATP, and play important roles in regulating a variety of physiological processes, including cardiovascular function, neurotransmission, and immune response.

Purinergic P1 receptor antagonists work by binding to these receptors and preventing them from being activated by nucleotides. This can have various therapeutic effects, depending on the specific receptor subtype that is targeted. For example, A1 receptor antagonists have been shown to improve cardiac function in heart failure, while A2A receptor antagonists have potential as anti-inflammatory and neuroprotective agents.

However, it's important to note that the use of purinergic P1 receptor antagonists is still an area of active research, and more studies are needed to fully understand their mechanisms of action and therapeutic potential.

Adenosine A1 receptor antagonists are a class of pharmaceutical compounds that block the action of adenosine at A1 receptors. Adenosine is a naturally occurring purine nucleoside that acts as a neurotransmitter and modulator of various physiological processes, including cardiovascular function, neuronal excitability, and immune response.

Adenosine exerts its effects by binding to specific receptors on the surface of cells, including A1, A2A, A2B, and A3 receptors. The activation of A1 receptors leads to a variety of physiological responses, such as vasodilation, negative chronotropy (slowing of heart rate), and negative inotropy (reduced contractility) of the heart, as well as inhibition of neurotransmitter release in the brain.

Adenosine A1 receptor antagonists work by binding to and blocking the action of adenosine at A1 receptors, thereby preventing or reducing its effects on these physiological processes. These drugs have been investigated for their potential therapeutic uses in various conditions, such as heart failure, cardiac arrest, and neurological disorders.

Examples of adenosine A1 receptor antagonists include:

* Dipyridamole: a vasodilator used to treat peripheral arterial disease and to prevent blood clots.
* Caffeine: a natural stimulant found in coffee, tea, and chocolate, which acts as a weak A1 receptor antagonist.
* Rolofylline: an experimental drug that has been investigated for its potential use in treating acute ischemic stroke and traumatic brain injury.
* KW-3902: another experimental drug that has been studied for its potential therapeutic effects in heart failure, cardiac arrest, and neurodegenerative disorders.

It's important to note that adenosine A1 receptor antagonists may have side effects and potential risks, and their use should be monitored and managed by healthcare professionals.

RNA editing is a process that alters the sequence of a transcribed RNA molecule after it has been synthesized from DNA, but before it is translated into protein. This can result in changes to the amino acid sequence of the resulting protein or to the regulation of gene expression. The most common type of RNA editing in mammals is the hydrolytic deamination of adenosine (A) to inosine (I), catalyzed by a family of enzymes called adenosine deaminases acting on RNA (ADARs). Inosine is recognized as guanosine (G) by the translation machinery, leading to A-to-G changes in the RNA sequence. Other types of RNA editing include cytidine (C) to uridine (U) deamination and insertion/deletion of nucleotides. RNA editing is a crucial mechanism for generating diversity in gene expression and has been implicated in various biological processes, including development, differentiation, and disease.

Adenosine A1 receptor agonists are medications or substances that bind to and activate the adenosine A1 receptors, which are found on the surface of certain cells in the body, including those in the heart, brain, and other organs.

Adenosine is a naturally occurring molecule in the body that helps regulate various physiological processes, such as cardiovascular function and neurotransmission. The adenosine A1 receptor plays an important role in modulating the activity of the heart, including reducing heart rate and lowering blood pressure.

Adenosine A1 receptor agonists are used clinically to treat certain medical conditions, such as supraventricular tachycardia (a rapid heart rhythm originating from above the ventricles), and to prevent cerebral vasospasm (narrowing of blood vessels in the brain) following subarachnoid hemorrhage.

Examples of adenosine A1 receptor agonists include adenosine, regadenoson, and capadenoson. These medications work by mimicking the effects of naturally occurring adenosine on the A1 receptors, leading to a decrease in heart rate and blood pressure.

It's important to note that adenosine A1 receptor agonists can have side effects, such as chest pain, shortness of breath, and flushing, which are usually transient and mild. However, they should be used with caution and under the supervision of a healthcare professional, as they can also have more serious side effects in certain individuals.

Purinergic P1 receptor agonists are substances that bind to and activate purinergic P1 receptors, which are a type of G protein-coupled receptor found in many tissues throughout the body. These receptors are activated by endogenous nucleotides such as adenosine and its metabolites.

Purinergic P1 receptors include four subtypes: A1, A2A, A2B, and A3. Each of these subtypes has distinct signaling pathways and physiological roles. For example, A1 receptor activation can lead to vasodilation, bradycardia, and anti-inflammatory effects, while A2A receptor activation can increase cyclic AMP levels and have anti-inflammatory effects.

Purinergic P1 receptor agonists are used in various therapeutic applications, including as cardiovascular drugs, antiplatelet agents, and anti-inflammatory agents. Some examples of purinergic P1 receptor agonists include adenosine, regadenoson, and dipyridamole.

It's important to note that the use of these substances should be under medical supervision due to their potential side effects and interactions with other medications.

Phenylisopropyladenosine (PIA) is not typically defined in the context of medical terminology, but rather it is a term used in pharmacology and biochemistry. PIA is a type of adenosine receptor agonist that specifically binds to and activates the A1 adenosine receptor.

Adenosine receptors are a type of G protein-coupled receptor (GPCR) found in various tissues throughout the body, including the brain, heart, and immune system. Activation of these receptors by agonists like PIA can have diverse effects on cellular function, such as modulating neurotransmission, reducing heart rate and contractility, and regulating inflammation.

While not a medical term per se, PIA is an important compound in the study of adenosine receptor biology and has potential therapeutic applications in various diseases, including neurological disorders, cardiovascular disease, and cancer.

Purine-nucleoside phosphorylase (PNP) is an enzyme that plays a crucial role in the metabolism of purines, which are essential components of nucleic acids (DNA and RNA). The medical definition of 'Purine-Nucleoside Phosphorylase' refers to the physiological function of this enzyme in the human body.

PNP is responsible for catalyzing the phosphorolytic cleavage of purine nucleosides, such as inosine and guanosine, into their respective purine bases (hypoxanthine and guanine) and ribose-1-phosphate. This reaction is essential for the recycling and salvage of purine bases, allowing the body to conserve energy and resources needed for de novo purine biosynthesis.

In a clinical or medical context, deficiencies in PNP activity can lead to serious consequences, particularly affecting the immune system and the nervous system. A genetic disorder called Purine-Nucleoside Phosphorylase Deficiency (PNP Deficiency) is characterized by significantly reduced or absent PNP enzyme activity, leading to an accumulation of toxic purine nucleosides and deoxypurine nucleosides. This accumulation can cause severe combined immunodeficiency (SCID), neurological impairments, and other complications, making it a critical area of study in medical research.

Adenosine monophosphate (AMP) is a nucleotide that is the monophosphate ester of adenosine, consisting of the nitrogenous base adenine attached to the 1' carbon atom of ribose via a β-N9-glycosidic bond, which in turn is esterified to a phosphate group. It is an important molecule in biological systems as it plays a key role in cellular energy transfer and storage, serving as a precursor to other nucleotides such as ADP and ATP. AMP is also involved in various signaling pathways and can act as a neurotransmitter in the central nervous system.

Aminohydrolases are a class of enzymes that catalyze the hydrolysis of amide bonds and the breakdown of urea, converting it into ammonia and carbon dioxide. They are also known as amidases or urease. These enzymes play an essential role in various biological processes, including nitrogen metabolism and the detoxification of xenobiotics.

Aminohydrolases can be further classified into several subclasses based on their specificity for different types of amide bonds. For example, peptidases are a type of aminohydrolase that specifically hydrolyze peptide bonds in proteins and peptides. Other examples include ureases, which hydrolyze urea, and acylamidases, which hydrolyze acylamides.

Aminohydrolases are widely distributed in nature and can be found in various organisms, including bacteria, fungi, plants, and animals. They have important applications in biotechnology and medicine, such as in the production of pharmaceuticals, the treatment of wastewater, and the diagnosis of genetic disorders.

Immunologic deficiency syndromes refer to a group of disorders characterized by defective functioning of the immune system, leading to increased susceptibility to infections and malignancies. These deficiencies can be primary (genetic or congenital) or secondary (acquired due to environmental factors, medications, or diseases).

Primary immunodeficiency syndromes (PIDS) are caused by inherited genetic mutations that affect the development and function of immune cells, such as T cells, B cells, and phagocytes. Examples include severe combined immunodeficiency (SCID), common variable immunodeficiency (CVID), Wiskott-Aldrich syndrome, and X-linked agammaglobulinemia.

Secondary immunodeficiency syndromes can result from various factors, including:

1. HIV/AIDS: Human Immunodeficiency Virus infection leads to the depletion of CD4+ T cells, causing profound immune dysfunction and increased vulnerability to opportunistic infections and malignancies.
2. Medications: Certain medications, such as chemotherapy, immunosuppressive drugs, and long-term corticosteroid use, can impair immune function and increase infection risk.
3. Malnutrition: Deficiencies in essential nutrients like protein, vitamins, and minerals can weaken the immune system and make individuals more susceptible to infections.
4. Aging: The immune system naturally declines with age, leading to an increased incidence of infections and poorer vaccine responses in older adults.
5. Other medical conditions: Chronic diseases such as diabetes, cancer, and chronic kidney or liver disease can also compromise the immune system and contribute to immunodeficiency syndromes.

Immunologic deficiency syndromes require appropriate diagnosis and management strategies, which may include antimicrobial therapy, immunoglobulin replacement, hematopoietic stem cell transplantation, or targeted treatments for the underlying cause.

Adenine is a purine nucleotide base that is a fundamental component of DNA and RNA, the genetic material of living organisms. In DNA, adenine pairs with thymine via double hydrogen bonds, while in RNA, it pairs with uracil. Adenine is essential for the structure and function of nucleic acids, as well as for energy transfer reactions in cells through its role in the formation of adenosine triphosphate (ATP), the primary energy currency of the cell.

Deamination is a biochemical process that refers to the removal of an amino group (-NH2) from a molecule, especially from an amino acid. This process typically results in the formation of a new functional group and the release of ammonia (NH3). Deamination plays a crucial role in the metabolism of amino acids, as it helps to convert them into forms that can be excreted or used for energy production. In some cases, deamination can also lead to the formation of toxic byproducts, which must be efficiently eliminated from the body to prevent harm.

Theophylline is a medication that belongs to a class of drugs called methylxanthines. It is used in the management of respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and other conditions that cause narrowing of the airways in the lungs.

Theophylline works by relaxing the smooth muscle around the airways, which helps to open them up and make breathing easier. It also acts as a bronchodilator, increasing the flow of air into and out of the lungs. Additionally, theophylline has anti-inflammatory effects that can help reduce swelling in the airways and relieve symptoms such as coughing, wheezing, and shortness of breath.

Theophylline is available in various forms, including tablets, capsules, and liquid solutions. It is important to take this medication exactly as prescribed by a healthcare provider, as the dosage may vary depending on individual factors such as age, weight, and liver function. Regular monitoring of blood levels of theophylline is also necessary to ensure safe and effective use of the medication.

2-Chloroadenosine is a synthetic, chlorinated analog of adenosine, which is a naturally occurring purine nucleoside. It acts as an antagonist at adenosine receptors and has been studied for its potential effects on the cardiovascular system, including its ability to reduce heart rate and blood pressure. It may also have anti-cancer properties and has been investigated as a potential therapeutic agent in cancer treatment. However, further research is needed to establish its safety and efficacy in clinical settings.

Pleural effusion is a medical condition characterized by the abnormal accumulation of fluid in the pleural space, which is the thin, fluid-filled space that surrounds the lungs and lines the inside of the chest wall. This space typically contains a small amount of fluid to allow for smooth movement of the lungs during breathing. However, when an excessive amount of fluid accumulates, it can cause symptoms such as shortness of breath, coughing, and chest pain.

Pleural effusions can be caused by various underlying medical conditions, including pneumonia, heart failure, cancer, pulmonary embolism, and autoimmune disorders. The fluid that accumulates in the pleural space can be transudative or exudative, depending on the cause of the effusion. Transudative effusions are caused by increased pressure in the blood vessels or decreased protein levels in the blood, while exudative effusions are caused by inflammation, infection, or cancer.

Diagnosis of pleural effusion typically involves a physical examination, chest X-ray, and analysis of the fluid in the pleural space. Treatment depends on the underlying cause of the effusion and may include medications, drainage of the fluid, or surgery.

Dipeptidyl peptidase 4 (DPP-4) is a serine protease enzyme that is widely distributed in various tissues and organs, including the kidney, liver, intestines, and immune cells. It plays a crucial role in regulating several biological processes, such as glucose metabolism, immune function, and cell signaling.

In terms of glucose metabolism, DPP-4 is responsible for breaking down incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which are released from the gut in response to food intake. These hormones stimulate insulin secretion from pancreatic beta cells, suppress glucagon release, and promote satiety, thereby helping to regulate blood sugar levels. By degrading GLP-1 and GIP, DPP-4 reduces their activity and contributes to the development of type 2 diabetes.

DPP-4 inhibitors are a class of drugs used to treat type 2 diabetes by blocking the action of DPP-4 and increasing incretin hormone levels, leading to improved insulin secretion and glucose control.

Deoxyadenine nucleotides are the chemical components that make up DNA, one of the building blocks of life. Specifically, deoxyadenine nucleotides contain a sugar molecule called deoxyribose, a phosphate group, and the nitrogenous base adenine. Adenine always pairs with thymine in DNA through hydrogen bonding. Together, these components form the building blocks of the genetic code that determines many of an organism's traits and characteristics.

Severe Combined Immunodeficiency (SCID) is a group of rare genetic disorders characterized by deficient or absent immune responses. It results from mutations in different genes involved in the development and function of T lymphocytes, B lymphocytes, or both, leading to a severe impairment in cell-mediated and humoral immunity.

Infants with SCID are extremely vulnerable to infections, which can be life-threatening. Common symptoms include chronic diarrhea, failure to thrive, recurrent pneumonia, and persistent candidiasis (thrush). If left untreated, it can lead to severe disability or death within the first two years of life. Treatment typically involves bone marrow transplantation or gene therapy to restore immune function.

Inborn errors of purine-pyrimidine metabolism refer to genetic disorders that result in dysfunctional enzymes involved in the metabolic pathways of purines and pyrimidines. These are essential components of nucleotides, which in turn are building blocks of DNA and RNA.

Inherited as autosomal recessive or X-linked recessive traits, these disorders can lead to an accumulation of toxic metabolites, a deficiency of necessary compounds, or both. Clinical features vary widely depending on the specific enzyme defect but may include neurologic symptoms, kidney problems, gout, and/or immunodeficiency.

Examples of such disorders include Lesch-Nyhan syndrome (deficiency of hypoxanthine-guanine phosphoribosyltransferase), adenosine deaminase deficiency (leading to severe combined immunodeficiency), and orotic aciduria (due to defects in pyrimidine metabolism). Early diagnosis and management are crucial to improve outcomes.

Purinergic receptors are a type of cell surface receptor that bind and respond to purines and pyrimidines, which are nucleotides and nucleosides. These receptors are involved in various physiological processes, including neurotransmission, muscle contraction, and inflammation. There are two main types of purinergic receptors: P1 receptors, which are activated by adenosine, and P2 receptors, which are activated by ATP and other nucleotides.

P2 receptors are further divided into two subtypes: P2X and P2Y. P2X receptors are ionotropic receptors that form cation channels upon activation, allowing the flow of ions such as calcium and sodium into the cell. P2Y receptors, on the other hand, are metabotropic receptors that activate G proteins upon activation, leading to the activation or inhibition of various intracellular signaling pathways.

Purinergic receptors have been found to play a role in many diseases and conditions, including neurological disorders, cardiovascular disease, and cancer. They are also being studied as potential targets for drug development.

Nucleotidases are a class of enzymes that catalyze the hydrolysis of nucleotides into nucleosides and phosphate groups. Nucleotidases play important roles in various biological processes, including the regulation of nucleotide concentrations within cells, the salvage pathways for nucleotide synthesis, and the breakdown of nucleic acids during programmed cell death (apoptosis).

There are several types of nucleotidases that differ in their substrate specificity and subcellular localization. These include:

1. Nucleoside monophosphatases (NMPs): These enzymes hydrolyze nucleoside monophosphates (NMPs) into nucleosides and inorganic phosphate.
2. Nucleoside diphosphatases (NDPs): These enzymes hydrolyze nucleoside diphosphates (NDPs) into nucleoside monophosphates (NMPs) and inorganic phosphate.
3. Nucleoside triphosphatases (NTPs): These enzymes hydrolyze nucleoside triphosphates (NTPs) into nucleoside diphosphates (NDPs) and inorganic phosphate.
4. 5'-Nucleotidase: This enzyme specifically hydrolyzes the phosphate group from the 5' position of nucleoside monophosphates, producing nucleosides.
5. Pyrophosphatases: These enzymes hydrolyze pyrophosphates into two phosphate groups and play a role in regulating nucleotide metabolism.

Nucleotidases are widely distributed in nature and can be found in various tissues, organs, and biological fluids, including blood, urine, and cerebrospinal fluid. Dysregulation of nucleotidase activity has been implicated in several diseases, such as cancer, neurodegenerative disorders, and infectious diseases.

Electrophoresis, starch gel is a type of electrophoretic technique used in laboratory settings for the separation and analysis of large biomolecules such as DNA, RNA, and proteins. In this method, a gel made from cooked starch is used as the supporting matrix for the molecules being separated.

The sample containing the mixture of biomolecules is loaded onto the gel and an electric field is applied, causing the negatively charged molecules to migrate towards the positive electrode. The starch gel acts as a molecular sieve, with smaller molecules moving more quickly through the gel than larger ones. This results in the separation of the mixture into individual components based on their size and charge.

Once the separation is complete, the gel can be stained to visualize the separated bands. Different staining techniques are used depending on the type of biomolecule being analyzed. For example, proteins can be stained with dyes such as Coomassie Brilliant Blue or silver nitrate, while nucleic acids can be stained with dyes such as ethidium bromide.

Starch gel electrophoresis is a relatively simple and inexpensive technique that has been widely used in molecular biology research and diagnostic applications. However, it has largely been replaced by other electrophoretic techniques, such as polyacrylamide gel electrophoresis (PAGE), which offer higher resolution and can be automated for high-throughput analysis.

Adenine nucleotides are molecules that consist of a nitrogenous base called adenine, which is linked to a sugar molecule (ribose in the case of adenosine monophosphate or AMP, and deoxyribose in the case of adenosine diphosphate or ADP and adenosine triphosphate or ATP) and one, two, or three phosphate groups. These molecules play a crucial role in energy transfer and metabolism within cells.

AMP contains one phosphate group, while ADP contains two phosphate groups, and ATP contains three phosphate groups. When a phosphate group is removed from ATP, energy is released, which can be used to power various cellular processes such as muscle contraction, nerve impulse transmission, and protein synthesis. The reverse reaction, in which a phosphate group is added back to ADP or AMP to form ATP, requires energy input and often involves the breakdown of nutrients such as glucose or fatty acids.

In addition to their role in energy metabolism, adenine nucleotides also serve as precursors for other important molecules, including DNA and RNA, coenzymes, and signaling molecules.

Hydroxymethylbilane Synthase (HMBS) is an enzyme that plays a crucial role in the metabolic pathway known as heme biosynthesis. Heme is an essential component of various proteins, including hemoglobin, which is responsible for oxygen transport in the blood.

The HMBS enzyme catalyzes the conversion of aminolevulinic acid (ALA) and glycine into a linear tetrapyrrole intermediate called hydroxymethylbilane. This reaction is the third step in the heme biosynthesis pathway, and it takes place in the mitochondria of cells.

Deficiencies in HMBS can lead to a rare genetic disorder called acute intermittent porphyria (AIP), which is characterized by neurovisceral attacks and neurological symptoms such as abdominal pain, vomiting, hypertension, tachycardia, and mental disturbances.

Adenosylhomocysteinase is an enzyme that plays a crucial role in the methionine cycle, which is a biochemical pathway involved in the synthesis and metabolism of various essential molecules in the body. The formal medical definition of adenosylhomocysteinase is:

"An enzyme that catalyzes the reversible conversion of S-adenosylhomocysteine to homocysteine and adenosine. This reaction is the first step in the recycling of methionine, a sulfur-containing amino acid that is essential for various metabolic processes, including the synthesis of proteins, neurotransmitters, and phospholipids."

In simpler terms, adenosylhomocysteinase helps break down S-adenosylhomocysteine, a byproduct of methylation reactions in the body, into its component parts: homocysteine and adenosine. This breakdown is essential for the proper functioning of the methionine cycle and the maintenance of normal levels of homocysteine, which can be toxic at high concentrations.

Deficiencies or mutations in the adenosylhomocysteinase gene can lead to an accumulation of S-adenosylhomocysteine and homocysteine, which can contribute to various health issues, including neurological disorders, cardiovascular disease, and developmental abnormalities.

Purines are heterocyclic aromatic organic compounds that consist of a pyrimidine ring fused to an imidazole ring. They are fundamental components of nucleotides, which are the building blocks of DNA and RNA. In the body, purines can be synthesized endogenously or obtained through dietary sources such as meat, seafood, and certain vegetables.

Once purines are metabolized, they are broken down into uric acid, which is excreted by the kidneys. Elevated levels of uric acid in the body can lead to the formation of uric acid crystals, resulting in conditions such as gout or kidney stones. Therefore, maintaining a balanced intake of purine-rich foods and ensuring proper kidney function are essential for overall health.

Hypoxanthine is not a medical condition but a purine base that is a component of many organic compounds, including nucleotides and nucleic acids, which are the building blocks of DNA and RNA. In the body, hypoxanthine is produced as a byproduct of normal cellular metabolism and is converted to xanthine and then uric acid, which is excreted in the urine.

However, abnormally high levels of hypoxanthine in the body can indicate tissue damage or disease. For example, during intense exercise or hypoxia (low oxygen levels), cells may break down ATP (adenosine triphosphate) rapidly, releasing large amounts of hypoxanthine. Similarly, in some genetic disorders such as Lesch-Nyhan syndrome, there is an accumulation of hypoxanthine due to a deficiency of the enzyme that converts it to xanthine. High levels of hypoxanthine can lead to the formation of kidney stones and other complications.

Hypoxanthine is a purine derivative and an intermediate in the metabolic pathways of nucleotide degradation, specifically adenosine to uric acid in humans. It is formed from the oxidation of xanthine by the enzyme xanthine oxidase. In the body, hypoxanthine is converted to xanthine and then to uric acid, which is excreted in the urine. Increased levels of hypoxanthine in the body can be indicative of various pathological conditions, including tissue hypoxia, ischemia, and necrosis.

Pentosyltransferases are a group of enzymes that catalyze the transfer of a pentose (a sugar containing five carbon atoms) molecule from one compound to another. These enzymes play important roles in various biochemical pathways, including the biosynthesis of nucleotides, glycoproteins, and other complex carbohydrates.

One example of a pentosyltransferase is the enzyme that catalyzes the addition of a ribose sugar to form a glycosidic bond with a purine or pyrimidine base during the biosynthesis of nucleotides, which are the building blocks of DNA and RNA.

Another example is the enzyme that adds xylose residues to proteins during the formation of glycoproteins, which are proteins that contain covalently attached carbohydrate chains. These enzymes are essential for many biological processes and have been implicated in various diseases, including cancer and neurodegenerative disorders.

Phenethylamines are a class of organic compounds that share a common structural feature, which is a phenethyl group (a phenyl ring bonded to an ethylamine chain). In the context of pharmacology and neuroscience, "phenethylamines" often refers to a specific group of psychoactive drugs, including stimulants like amphetamine and mescaline, a classic psychedelic. These compounds exert their effects by modulating the activity of neurotransmitters in the brain, such as dopamine, norepinephrine, and serotonin. It is important to note that many phenethylamines have potential for abuse and are controlled substances.

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

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

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

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

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

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

Clinical enzyme tests are laboratory tests that measure the amount or activity of certain enzymes in biological samples, such as blood or bodily fluids. These tests are used to help diagnose and monitor various medical conditions, including organ damage, infection, inflammation, and genetic disorders.

Enzymes are proteins that catalyze chemical reactions in the body. Some enzymes are found primarily within specific organs or tissues, so elevated levels of these enzymes in the blood can indicate damage to those organs or tissues. For example, high levels of creatine kinase (CK) may suggest muscle damage, while increased levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) can indicate liver damage.

There are several types of clinical enzyme tests, including:

1. Serum enzyme tests: These measure the level of enzymes in the blood serum, which is the liquid portion of the blood after clotting. Examples include CK, AST, ALT, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH).
2. Urine enzyme tests: These measure the level of enzymes in the urine. An example is N-acetyl-β-D-glucosaminidase (NAG), which can indicate kidney damage.
3. Enzyme immunoassays (EIAs): These use antibodies to detect and quantify specific enzymes or proteins in a sample. They are often used for the diagnosis of infectious diseases, such as HIV or hepatitis.
4. Genetic enzyme tests: These can identify genetic mutations that cause deficiencies in specific enzymes, leading to inherited metabolic disorders like phenylketonuria (PKU) or Gaucher's disease.

It is important to note that the interpretation of clinical enzyme test results should be done by a healthcare professional, taking into account the patient's medical history, symptoms, and other diagnostic tests.

A nucleoside is a biochemical molecule that consists of a pentose sugar (a type of simple sugar with five carbon atoms) covalently linked to a nitrogenous base. The nitrogenous base can be one of several types, including adenine, guanine, cytosine, thymine, or uracil. Nucleosides are important components of nucleic acids, such as DNA and RNA, which are the genetic materials found in cells. They play a crucial role in various biological processes, including cell division, protein synthesis, and gene expression.

Cyclic adenosine monophosphate (cAMP) is a key secondary messenger in many biological processes, including the regulation of metabolism, gene expression, and cellular excitability. It is synthesized from adenosine triphosphate (ATP) by the enzyme adenylyl cyclase and is degraded by the enzyme phosphodiesterase.

In the body, cAMP plays a crucial role in mediating the effects of hormones and neurotransmitters on target cells. For example, when a hormone binds to its receptor on the surface of a cell, it can activate a G protein, which in turn activates adenylyl cyclase to produce cAMP. The increased levels of cAMP then activate various effector proteins, such as protein kinases, which go on to regulate various cellular processes.

Overall, the regulation of cAMP levels is critical for maintaining proper cellular function and homeostasis, and abnormalities in cAMP signaling have been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Carbon-carbon lyases are a class of enzymes that catalyze the breaking of carbon-carbon bonds in a substrate, resulting in the formation of two molecules with a double bond between them. This reaction is typically accompanied by the release or addition of a cofactor such as water or a coenzyme.

These enzymes play important roles in various metabolic pathways, including the breakdown of carbohydrates, lipids, and amino acids. They are also involved in the biosynthesis of secondary metabolites, such as terpenoids and alkaloids.

Carbon-carbon lyases are classified under EC number 4.1.2. in the Enzyme Commission (EC) system. This classification includes a wide range of enzymes with different substrate specificities and reaction mechanisms. Examples of carbon-carbon lyases include decarboxylases, aldolases, and dehydratases.

It's worth noting that the term "lyase" refers to any enzyme that catalyzes the removal of a group of atoms from a molecule, leaving a double bond or a cycle, and it does not necessarily imply the formation of carbon-carbon bonds.

Purine nucleosides are fundamental components of nucleic acids, which are the genetic materials found in all living organisms. A purine nucleoside is composed of a purine base (either adenine or guanine) linked to a sugar molecule, specifically ribose in the case of purine nucleosides.

The purine base and sugar moiety are joined together through a glycosidic bond at the 1' position of the sugar. These nucleosides play crucial roles in various biological processes, including energy transfer, signal transduction, and as precursors for the biosynthesis of DNA and RNA.

In the human body, purine nucleosides can be derived from the breakdown of endogenous nucleic acids or through the dietary intake of nucleoproteins. They are further metabolized to form uric acid, which is eventually excreted in the urine. Elevated levels of uric acid in the body can lead to the formation of uric acid crystals and contribute to the development of gout or kidney stones.

Leukemia, lymphoid is a type of cancer that affects the lymphoid cells, which are a vital part of the body's immune system. It is characterized by the uncontrolled production of abnormal white blood cells (leukocytes or WBCs) in the bone marrow, specifically the lymphocytes. These abnormal lymphocytes accumulate and interfere with the production of normal blood cells, leading to a decrease in red blood cells (anemia), platelets (thrombocytopenia), and healthy white blood cells (leukopenia).

There are two main types of lymphoid leukemia: acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL). Acute lymphoblastic leukemia progresses rapidly, while chronic lymphocytic leukemia has a slower onset and progression.

Symptoms of lymphoid leukemia may include fatigue, frequent infections, easy bruising or bleeding, weight loss, swollen lymph nodes, and bone pain. Treatment options depend on the type, stage, and individual patient factors but often involve chemotherapy, radiation therapy, targeted therapy, immunotherapy, or stem cell transplantation.

Erythrocytes, also known as red blood cells (RBCs), are the most common type of blood cell in circulating blood in mammals. They are responsible for transporting oxygen from the lungs to the body's tissues and carbon dioxide from the tissues to the lungs.

Erythrocytes are formed in the bone marrow and have a biconcave shape, which allows them to fold and bend easily as they pass through narrow blood vessels. They do not have a nucleus or mitochondria, which makes them more flexible but also limits their ability to reproduce or repair themselves.

In humans, erythrocytes are typically disc-shaped and measure about 7 micrometers in diameter. They contain the protein hemoglobin, which binds to oxygen and gives blood its red color. The lifespan of an erythrocyte is approximately 120 days, after which it is broken down in the liver and spleen.

Abnormalities in erythrocyte count or function can lead to various medical conditions, such as anemia, polycythemia, and sickle cell disease.

Adenosine A3 receptor antagonists are a class of pharmaceutical compounds that block the action of adenosine at the A3 receptor. Adenosine is a naturally occurring purine nucleoside that acts as a neurotransmitter and modulator of various physiological processes, including cardiovascular function, immune response, and neuromodulation.

The A3 receptor is one of four subtypes of adenosine receptors (A1, A2A, A2B, and A3) that are widely distributed throughout the body. The activation of A3 receptors has been implicated in a variety of pathological conditions, including inflammation, pain, ischemia-reperfusion injury, and cancer.

Adenosine A3 receptor antagonists have been investigated as potential therapeutic agents for various diseases, such as rheumatoid arthritis, chronic pain, ischemic heart disease, and cancer. These compounds work by preventing the binding of adenosine to its receptor, thereby blocking its downstream signaling pathways.

Some examples of Adenosine A3 receptor antagonists include:

* MRS1523
* MRE-2029F20
* LUF5834
* VUF5574
* OT-7962

It is important to note that while Adenosine A3 receptor antagonists have shown promise in preclinical studies, their clinical efficacy and safety profile are still being evaluated in ongoing research.

Dipyridamole is a medication that belongs to a class of drugs called antiplatelet agents. It works by preventing platelets in your blood from sticking together to form clots. Dipyridamole is often used in combination with aspirin to prevent stroke and other complications in people who have had a heart valve replacement or a type of irregular heartbeat called atrial fibrillation.

Dipyridamole can also be used as a stress agent in myocardial perfusion imaging studies, which are tests used to evaluate blood flow to the heart. When used for this purpose, dipyridamole is given intravenously and works by dilating the blood vessels in the heart, allowing more blood to flow through them and making it easier to detect areas of reduced blood flow.

The most common side effects of dipyridamole include headache, dizziness, and gastrointestinal symptoms such as diarrhea, nausea, and vomiting. In rare cases, dipyridamole can cause more serious side effects, such as allergic reactions, abnormal heart rhythms, or low blood pressure. It is important to take dipyridamole exactly as directed by your healthcare provider and to report any unusual symptoms or side effects promptly.

Tuberculous pericarditis is a specific form of pericarditis (inflammation of the pericardium, the thin sac-like membrane that surrounds the heart) that is caused by the bacterial infection of Mycobacterium tuberculosis. This type of pericarditis is more common in areas where tuberculosis is prevalent and can lead to serious complications if not diagnosed and treated promptly.

In tuberculous pericarditis, the bacteria typically spread from the lungs (the most common site of TB infection) or other infected organs through the bloodstream to the pericardium. The infection causes an inflammatory response, leading to the accumulation of fluid in the pericardial space (pericardial effusion), which can put pressure on the heart and impair its function. In some cases, the inflammation may lead to the formation of scar tissue, causing the pericardium to thicken and constrict, a condition known as constrictive pericarditis.

Symptoms of tuberculous pericarditis can include chest pain, cough, fever, fatigue, weight loss, and difficulty breathing. Diagnosis typically involves a combination of medical history, physical examination, imaging tests (such as echocardiography, CT scan, or MRI), and laboratory tests (including analysis of the pericardial fluid). Treatment usually consists of a long course of antibiotics specific to TB, along with anti-inflammatory medications and close monitoring for potential complications.

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.

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.

Thioinosine is not a medical term itself, but it is a chemical compound that has been studied in the field of medical research. Thioinosine is an analogue of the nucleoside inosine, where the oxygen atom in the heterocyclic ring is replaced by a sulfur atom.

In the context of medical research, thioinosine has been investigated for its potential immunomodulatory and antiviral properties. It has been studied as an inhibitor of certain enzymes involved in the replication of viruses, such as HIV and hepatitis C virus. However, it is not currently approved for use as a medication in clinical practice.

Threonine Dehydratase is not a medical term per se, but rather a biochemical term. It refers to an enzyme that catalyzes the chemical reaction in which the amino acid threonine is converted into 2-oxobutanoate and ammonia. This reaction is part of the metabolic pathway for the breakdown of certain amino acids for energy production in the body.

The medical relevance of Threonine Dehydratase comes from its role in various genetic disorders, such as maple syrup urine disease (MSUD), where a deficiency in this enzyme can lead to an accumulation of certain amino acids and result in neurological symptoms.

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.

Adenosine A3 receptor agonists are a type of pharmaceutical compound that bind to and activate the adenosine A3 receptor, which is a type of G-protein coupled receptor found in various tissues throughout the body. Activation of the A3 receptor has been shown to have anti-inflammatory and analgesic effects, making it a target for the development of drugs to treat conditions such as rheumatoid arthritis, inflammatory bowel disease, and chronic pain. Examples of adenosine A3 receptor agonists include IB-MECA, Cl-IB-MECA, and MRS1523.

"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.

Tuberculous peritonitis is a specific type of peritonitis (inflammation of the peritoneum, the serous membrane that lines the abdominal cavity and covers the abdominal organs) that is caused by the Mycobacterium tuberculosis bacterium. This form of peritonitis is less common than peritonitis caused by other types of bacteria, but it can occur in people with weakened immune systems or those who have been in close contact with individuals with active TB.

The symptoms of tuberculous peritonitis may include abdominal pain and distension, fever, weight loss, decreased appetite, and ascites (accumulation of fluid in the abdominal cavity). Diagnosis typically involves a combination of clinical evaluation, imaging studies, and laboratory tests, such as cultures or nucleic acid amplification tests (NAATs) to detect the presence of M. tuberculosis in the peritoneal fluid or tissue. Treatment usually involves a prolonged course of multiple antibiotics that are active against M. tuberculosis, along with supportive care to manage any complications or symptoms.

Flucytosine is an antifungal medication used to treat serious and life-threatening fungal infections, such as cryptococcal meningitis and candidiasis. It works by interfering with the production of DNA and RNA in the fungal cells, which inhibits their growth and reproduction.

The medical definition of Flucytosine is:

A synthetic fluorinated pyrimidine nucleoside analogue that is converted to fluorouracil after uptake into susceptible fungal cells. It is used as an antifungal agent in the treatment of serious systemic fungal infections, particularly those caused by Candida and Cryptococcus neoformans. Flucytosine has both fungistatic and fungicidal activity, depending on the concentration achieved at the site of infection and the susceptibility of the organism.

Flucytosine is available in oral form and is often used in combination with other antifungal agents to increase its effectiveness and prevent the development of resistance. Common side effects include nausea, vomiting, diarrhea, and bone marrow suppression. Regular monitoring of blood counts and liver function tests is necessary during treatment to detect any potential toxicity.

Deoxyribonucleosides are chemical compounds that constitute the basic building blocks of DNA, one of the two nucleic acids found in cells. They consist of a sugar molecule called deoxyribose, a nitrogenous base (either adenine, guanine, cytosine, or thymine), and a phosphate group.

The nitrogenous base is attached to the 1' carbon atom of the deoxyribose sugar, forming a glycosidic bond. The phosphate group is linked to the 5' carbon atom of the deoxyribose sugar through an ester linkage, creating a phosphodiester bond with another deoxyribonucleoside.

When multiple deoxyribonucleosides are joined together through their phosphate groups, they form a polynucleotide chain, which is the backbone of DNA. The sequence of nitrogenous bases along this chain encodes genetic information that determines the characteristics and functions of living organisms.

Deoxyribonucleosides play a crucial role in various biological processes, including DNA replication, repair, and transcription. They are also used as therapeutic agents for the treatment of certain genetic disorders and cancer.

Dideoxyadenosine (ddA) is a type of synthetic nucleoside analogue, which is a synthetic compound that resembles one of the building blocks of DNA or RNA. More specifically, ddA resembles adenosine, one of the four nucleosides that make up DNA.

Dideoxyadenosine is used in research and medicine as an inhibitor of reverse transcriptase, an enzyme that is produced by retroviruses such as HIV. By blocking the action of this enzyme, ddA can prevent the virus from replicating and infecting new cells.

Dideoxyadenosine is often used in combination with other antiretroviral drugs as part of highly active antiretroviral therapy (HAART) to treat HIV infection and AIDS. It is usually administered as a prodrug, such as didanosine or ddI, which is converted to the active form of the drug in the body.

It's important to note that Dideoxyadenosine itself is not used directly as a medication but its derivatives like Didanosine are used in treatment.

Formycins are a group of antibiotics that are derived from certain strains of Streptomyces bacteria. They include formycin B (also known as pyrazofurin), which is an antiviral and antimetabolite drug that works by interfering with the production of genetic material in cells. Formycins are not widely used in clinical medicine due to their potential toxicity and the availability of other effective antibiotics and antiviral drugs.

Vidarabine is an antiviral medication used to treat herpes simplex infections, particularly severe cases such as herpes encephalitis (inflammation of the brain caused by the herpes simplex virus). It works by interfering with the DNA replication of the virus.

In medical terms, vidarabine is a nucleoside analogue that is phosphorylated intracellularly to the active form, vidarabine triphosphate. This compound inhibits viral DNA polymerase and incorporates into viral DNA, causing termination of viral DNA synthesis.

Vidarabine was previously used as an injectable medication but has largely been replaced by more modern antiviral drugs such as acyclovir due to its greater efficacy and lower toxicity.

S-Adenosylhomocysteine (SAH) is a metabolic byproduct formed from the demethylation of various compounds or from the breakdown of S-adenosylmethionine (SAM), which is a major methyl group donor in the body. SAH is rapidly hydrolyzed to homocysteine and adenosine by the enzyme S-adenosylhomocysteine hydrolase. Increased levels of SAH can inhibit many methyltransferases, leading to disturbances in cellular metabolism and potential negative health effects.

Lymphocytes are a type of white blood cell that is an essential part of the immune system. They are responsible for recognizing and responding to potentially harmful substances such as viruses, bacteria, and other foreign invaders. There are two main types of lymphocytes: B-lymphocytes (B-cells) and T-lymphocytes (T-cells).

B-lymphocytes produce antibodies, which are proteins that help to neutralize or destroy foreign substances. When a B-cell encounters a foreign substance, it becomes activated and begins to divide and differentiate into plasma cells, which produce and secrete large amounts of antibodies. These antibodies bind to the foreign substance, marking it for destruction by other immune cells.

T-lymphocytes, on the other hand, are involved in cell-mediated immunity. They directly attack and destroy infected cells or cancerous cells. T-cells can also help to regulate the immune response by producing chemical signals that activate or inhibit other immune cells.

Lymphocytes are produced in the bone marrow and mature in either the bone marrow (B-cells) or the thymus gland (T-cells). They circulate throughout the body in the blood and lymphatic system, where they can be found in high concentrations in lymph nodes, the spleen, and other lymphoid organs.

Abnormalities in the number or function of lymphocytes can lead to a variety of immune-related disorders, including immunodeficiency diseases, autoimmune disorders, and cancer.

Inosine monophosphate (IMP) is a nucleotide that plays a crucial role in the metabolic pathways of energy production and purine synthesis in cells. It is an ester of the nucleoside inosine and phosphoric acid. IMP is an important intermediate in the conversion of adenosine monophosphate (AMP) to guanosine monophosphate (GMP) in the purine nucleotide cycle, which is critical for maintaining the balance of purine nucleotides in the body. Additionally, IMP can be converted back to AMP through the action of the enzyme adenylosuccinate lyase. IMP has been studied for its potential therapeutic benefits in various medical conditions, including neurodegenerative disorders and ischemia-reperfusion injury.

Purinergic antagonists are a class of drugs that block the action of purinergic receptors, which are specialized proteins found on the surface of cells that respond to purines such as ATP and ADP. These receptors play important roles in various physiological processes, including neurotransmission, inflammation, and cell death.

Purinergic antagonists work by binding to these receptors and preventing them from being activated by purines. This can have a variety of effects depending on the specific receptor that is blocked. For example, some purinergic antagonists are used in the treatment of conditions such as chronic pain, depression, and Parkinson's disease because they block receptors that play a role in these conditions.

It's important to note that while purinergic antagonists can be useful therapeutically, they can also have side effects and potential risks. As with any medication, it's important to use them only under the guidance of a healthcare professional.

Tetrahydrouridine (THU) is not a medication itself, but rather a metabolic inhibitor. It is a derivative of the nucleoside uridine and has been studied in the context of its ability to inhibit the enzyme cytidine deaminase. This enzyme is responsible for the breakdown of certain antiviral medications, such as zidovudine (AZT) and stavudine (d4T), which are used in the treatment of HIV infection.

By inhibiting cytidine deaminase, THU can help to increase the levels and effectiveness of these antiviral drugs, while also reducing some of their side effects. However, it is important to note that THU is not currently approved for use as a medication by itself and is typically used in research or experimental settings in combination with other antiretroviral therapies.

I'm happy to help! However, it seems there might be a slight misunderstanding in your question. RNA, or ribonucleic acid, is typically single-stranded. Unlike DNA, which is double-stranded and forms a double helix, RNA usually exists as a single strand of nucleotides.

There are exceptions to this rule, such as certain types of RNA molecules that can form double-stranded structures in specific contexts. For example:

1. Double-Stranded RNA (dsRNA) viruses: These viruses have genomes made entirely of RNA, which is double-stranded throughout or partially double-stranded. The dsRNA viruses include important pathogens such as rotaviruses and reoviruses.
2. Hairpin loops in RNA structures: Some single-stranded RNA molecules can fold back on themselves to form short double-stranded regions, called hairpin loops, within their overall structure. These are often found in ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA) molecules.

So, while 'double-stranded RNA' is not a standard medical definition for RNA itself, there are specific instances where RNA can form double-stranded structures as described above.

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

Pigmentation disorders are conditions that affect the production or distribution of melanin, the pigment responsible for the color of skin, hair, and eyes. These disorders can cause changes in the color of the skin, resulting in areas that are darker (hyperpigmentation) or lighter (hypopigmentation) than normal. Examples of pigmentation disorders include melasma, age spots, albinism, and vitiligo. The causes, symptoms, and treatments for these conditions can vary widely, so it is important to consult a healthcare provider for an accurate diagnosis and treatment plan.

Somatic hypermutation is a process that occurs in the immune system, specifically within B cells, which are a type of white blood cell responsible for producing antibodies. This process involves the introduction of point mutations into the immunoglobulin (Ig) genes, which encode for the variable regions of antibodies.

Somatic hypermutation occurs in the germinal centers of lymphoid follicles in response to antigen stimulation. The activation-induced cytidine deaminase (AID) enzyme is responsible for initiating this process by deaminating cytosines to uracils in the Ig genes. This leads to the introduction of point mutations during DNA replication and repair, which can result in changes to the antibody's binding affinity for the antigen.

The somatic hypermutation process allows for the selection of B cells with higher affinity antibodies that can better recognize and neutralize pathogens. This is an important mechanism for the development of humoral immunity and the generation of long-lived memory B cells. However, excessive or aberrant somatic hypermutation can also contribute to the development of certain types of B cell malignancies, such as lymphomas and leukemias.

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.

A gene is a specific sequence of nucleotides in DNA that carries genetic information. Genes are the fundamental units of heredity and are responsible for the development and function of all living organisms. They code for proteins or RNA molecules, which carry out various functions within cells and are essential for the structure, function, and regulation of the body's tissues and organs.

Each gene has a specific location on a chromosome, and each person inherits two copies of every gene, one from each parent. Variations in the sequence of nucleotides in a gene can lead to differences in traits between individuals, including physical characteristics, susceptibility to disease, and responses to environmental factors.

Medical genetics is the study of genes and their role in health and disease. It involves understanding how genes contribute to the development and progression of various medical conditions, as well as identifying genetic risk factors and developing strategies for prevention, diagnosis, and treatment.

Guanosine is a nucleoside that consists of a guanine base linked to a ribose sugar molecule through a beta-N9-glycosidic bond. It plays a crucial role in various biological processes, such as serving as a building block for DNA and RNA during replication and transcription. Guanosine triphosphate (GTP) and guanosine diphosphate (GDP) are important energy carriers and signaling molecules involved in intracellular regulation. Additionally, guanosine has been studied for its potential role as a neuroprotective agent and possible contribution to cell-to-cell communication.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Lipid mobilization, also known as lipolysis, is the process by which fat cells (adipocytes) break down stored triglycerides into free fatty acids and glycerol, which can then be released into the bloodstream and used for energy by the body's cells. This process is regulated by hormones such as adrenaline, noradrenaline, glucagon, and cortisol, which activate enzymes in the fat cell that catalyze the breakdown of triglycerides. Lipid mobilization is an important physiological response to fasting, exercise, and stress, and plays a key role in maintaining energy homeostasis in the body.

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.

Triazines are not a medical term, but a class of chemical compounds. They have a six-membered ring containing three nitrogen atoms and three carbon atoms. Some triazine derivatives are used in medicine as herbicides, antimicrobials, and antitumor agents.

Immunoglobulin class switching, also known as isotype switching or class switch recombination (CSR), is a biological process that occurs in B lymphocytes as part of the adaptive immune response. This mechanism allows a mature B cell to change the type of antibody it produces from one class to another (e.g., from IgM to IgG, IgA, or IgE) while keeping the same antigen-binding specificity.

During immunoglobulin class switching, the constant region genes of the heavy chain undergo a DNA recombination event, which results in the deletion of the original constant region exons and the addition of new constant region exons downstream. This switch allows the B cell to express different effector functions through the production of antibodies with distinct constant regions, tailoring the immune response to eliminate pathogens more effectively. The process is regulated by various cytokines and signals from T cells and is critical for mounting an effective humoral immune response.

Ammonia-lyases are a class of enzymes that catalyze the removal of an amino group from a substrate, releasing ammonia in the process. These enzymes play important roles in various biological pathways, including the biosynthesis and degradation of various metabolites such as amino acids, carbohydrates, and aromatic compounds.

The reaction catalyzed by ammonia-lyases typically involves the conversion of an alkyl or aryl group to a carbon-carbon double bond through the elimination of an amine group. This reaction is often reversible, allowing the enzyme to also catalyze the addition of an amino group to a double bond.

Ammonia-lyases are classified based on the type of substrate they act upon and the mechanism of the reaction they catalyze. Some examples of ammonia-lyases include aspartate ammonia-lyase, which catalyzes the conversion of aspartate to fumarate, and tyrosine ammonia-lyase, which converts tyrosine to p-coumaric acid.

These enzymes are important in both plant and animal metabolism and have potential applications in biotechnology and industrial processes.

Adenosine triphosphatases (ATPases) are a group of enzymes that catalyze the conversion of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate. This reaction releases energy, which is used to drive various cellular processes such as muscle contraction, transport of ions across membranes, and synthesis of proteins and nucleic acids.

ATPases are classified into several types based on their structure, function, and mechanism of action. Some examples include:

1. P-type ATPases: These ATPases form a phosphorylated intermediate during the reaction cycle and are involved in the transport of ions across membranes, such as the sodium-potassium pump and calcium pumps.
2. F-type ATPases: These ATPases are found in mitochondria, chloroplasts, and bacteria, and are responsible for generating a proton gradient across the membrane, which is used to synthesize ATP.
3. V-type ATPases: These ATPases are found in vacuolar membranes and endomembranes, and are involved in acidification of intracellular compartments.
4. A-type ATPases: These ATPases are found in the plasma membrane and are involved in various functions such as cell signaling and ion transport.

Overall, ATPases play a crucial role in maintaining the energy balance of cells and regulating various physiological processes.

Deoxycytidine kinase (dCK) is an enzyme that plays a crucial role in the phosphorylation of deoxycytidine and its analogs, which are important components in the intracellular metabolism of DNA precursors. The enzyme catalyzes the transfer of a phosphate group from adenosine triphosphate (ATP) to the hydroxyl group at the 5' carbon atom of deoxycytidine, forming deoxycytidine monophosphate (dCMP).

Deoxycytidine kinase is a key enzyme in the salvage pathway of pyrimidine nucleotide synthesis and is also involved in the activation of many antiviral and anticancer drugs that are analogs of deoxycytidine. The activity of dCK is tightly regulated, and its expression levels can vary depending on the cell type and physiological conditions.

In addition to its role in nucleotide metabolism, dCK has been implicated in various biological processes, including DNA damage response, cell cycle regulation, and apoptosis. Abnormalities in dCK activity or expression have been associated with several human diseases, including cancer and viral infections. Therefore, modulation of dCK activity has emerged as a potential therapeutic strategy for the treatment of these conditions.

Apyrase is an enzyme that catalyzes the hydrolysis of nucleoside triphosphates (like ATP or GTP) to nucleoside diphosphates (like ADP or GDP), releasing inorganic phosphate in the process. It can also hydrolyze nucleoside diphosphates to nucleoside monophosphates, releasing inorganic pyrophosphate.

This enzyme is widely distributed in nature and has been found in various organisms, including bacteria, plants, and animals. In humans, apyrases are present in different tissues, such as the brain, platelets, and red blood cells. They play essential roles in several biological processes, including signal transduction, metabolism regulation, and inflammatory response modulation.

There are two major classes of apyrases: type I (also known as nucleoside diphosphate kinase) and type II (also known as NTPDase). Type II apyrases have higher substrate specificity for nucleoside triphosphates, while type I apyrases can hydrolyze both nucleoside tri- and diphosphates.

In the medical field, apyrases are sometimes used in research to study platelet function or neurotransmission, as they can help regulate purinergic signaling by controlling extracellular levels of ATP and ADP. Additionally, some studies suggest that apyrase activity might be involved in certain pathological conditions, such as atherosclerosis, thrombosis, and neurological disorders.

L-serine dehydratase is an enzyme that plays a role in the metabolism of certain amino acids. Specifically, it catalyzes the conversion of L-serine to pyruvate and ammonia. This reaction is part of the pathway that breaks down L-serine to produce energy and intermediates for other biochemical processes in the body.

The systematic name for this enzyme is L-serine deaminase (pyruvate-forming). It is classified as a member of the lyase family of enzymes, which are characterized by their ability to catalyze the breaking of various chemical bonds using a cofactor to provide the energy needed for the reaction. In the case of L-serine dehydratase, the cofactor is a derivative of vitamin B6 called pyridoxal 5'-phosphate (PLP).

Deficiencies or mutations in the gene that encodes L-serine dehydratase can lead to various metabolic disorders, including hypermethioninemia and homocystinuria. These conditions are characterized by abnormal levels of certain amino acids in the blood and urine, which can have serious health consequences if left untreated.

DNA nucleotidylexotransferase is not a widely recognized or established medical term. It appears to be a combination of the terms "DNA," "nucleotide," and "lexotransferase," but the specific meaning or function of this enzyme is unclear.

"DNA" refers to deoxyribonucleic acid, which is the genetic material found in the cells of most living organisms.

"Nucleotide" refers to a molecule that consists of a nitrogenous base, a sugar, and one or more phosphate groups. Nucleotides are the building blocks of DNA and RNA.

"Lexotransferase" is not a recognized enzyme class or function. It may be a typographical error or a term that has been misused or misunderstood.

Therefore, it is not possible to provide a medical definition for 'DNA nucleotidylexotransferase'. If you have more information about the context in which this term was used, I may be able to provide further clarification.

Nucleoside transport proteins (NTTs) are membrane-bound proteins responsible for the facilitated diffusion of nucleosides and related deoxynucleosides across the cell membrane. These proteins play a crucial role in the uptake of nucleosides, which serve as precursors for DNA and RNA synthesis, as well as for the salvage of nucleotides in the cell.

There are two main types of NTTs: concentrative (or sodium-dependent) nucleoside transporters (CNTs) and equilibrative (or sodium-independent) nucleoside transporters (ENTs). CNTs mainly facilitate the uptake of nucleosides against a concentration gradient, using the energy derived from the sodium ion gradient. In contrast, ENTs mediate bidirectional transport, allowing for the equalization of intracellular and extracellular nucleoside concentrations.

Nucleoside transport proteins have been identified in various organisms, including humans, and are involved in numerous physiological processes, such as cell proliferation, differentiation, and survival. Dysregulation of NTTs has been implicated in several pathological conditions, including cancer and viral infections, making them potential targets for therapeutic intervention.

Lipolysis is the process by which fat cells (adipocytes) break down stored triglycerides into glycerol and free fatty acids. This process occurs when the body needs to use stored fat as a source of energy, such as during fasting, exercise, or in response to certain hormonal signals. The breakdown products of lipolysis can be used directly by cells for energy production or can be released into the bloodstream and transported to other tissues for use. Lipolysis is regulated by several hormones, including adrenaline (epinephrine), noradrenaline (norepinephrine), cortisol, glucagon, and growth hormone, which act on lipases, enzymes that mediate the breakdown of triglycerides.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Phosphotransferases are a group of enzymes that catalyze the transfer of a phosphate group from a donor molecule to an acceptor molecule. This reaction is essential for various cellular processes, including energy metabolism, signal transduction, and biosynthesis.

The systematic name for this group of enzymes is phosphotransferase, which is derived from the general reaction they catalyze: D-donor + A-acceptor = D-donor minus phosphate + A-phosphate. The donor molecule can be a variety of compounds, such as ATP or a phosphorylated protein, while the acceptor molecule is typically a compound that becomes phosphorylated during the reaction.

Phosphotransferases are classified into several subgroups based on the type of donor and acceptor molecules they act upon. For example, kinases are a subgroup of phosphotransferases that transfer a phosphate group from ATP to a protein or other organic compound. Phosphatases, another subgroup, remove phosphate groups from molecules by transferring them to water.

Overall, phosphotransferases play a critical role in regulating many cellular functions and are important targets for drug development in various diseases, including cancer and neurological disorders.

Hydrolases are a class of enzymes that help facilitate the breakdown of various types of chemical bonds through a process called hydrolysis, which involves the addition of water. These enzymes catalyze the cleavage of bonds in substrates by adding a molecule of water, leading to the formation of two or more smaller molecules.

Hydrolases play a crucial role in many biological processes, including digestion, metabolism, and detoxification. They can act on a wide range of substrates, such as proteins, lipids, carbohydrates, and nucleic acids, breaking them down into smaller units that can be more easily absorbed or utilized by the body.

Examples of hydrolases include:

1. Proteases: enzymes that break down proteins into smaller peptides or amino acids.
2. Lipases: enzymes that hydrolyze lipids, such as triglycerides, into fatty acids and glycerol.
3. Amylases: enzymes that break down complex carbohydrates, like starches, into simpler sugars, such as glucose.
4. Nucleases: enzymes that cleave nucleic acids, such as DNA or RNA, into smaller nucleotides or oligonucleotides.
5. Phosphatases: enzymes that remove phosphate groups from various substrates, including proteins and lipids.
6. Esterases: enzymes that hydrolyze ester bonds in a variety of substrates, such as those found in some drugs or neurotransmitters.

Hydrolases are essential for maintaining proper cellular function and homeostasis, and their dysregulation can contribute to various diseases and disorders.

Retroviridae is a family of viruses that includes human immunodeficiency virus (HIV) and other viruses that primarily use RNA as their genetic material. The name "retrovirus" comes from the fact that these viruses reverse transcribe their RNA genome into DNA, which then becomes integrated into the host cell's genome. This is a unique characteristic of retroviruses, as most other viruses use DNA as their genetic material.

Retroviruses can cause a variety of diseases in animals and humans, including cancer, neurological disorders, and immunodeficiency syndromes like AIDS. They have a lipid membrane envelope that contains glycoprotein spikes, which allow them to attach to and enter host cells. Once inside the host cell, the viral RNA is reverse transcribed into DNA by the enzyme reverse transcriptase, which is then integrated into the host genome by the enzyme integrase.

Retroviruses can remain dormant in the host genome for extended periods of time, and may be reactivated under certain conditions to produce new viral particles. This ability to integrate into the host genome has also made retroviruses useful tools in molecular biology, where they are used as vectors for gene therapy and other genetic manipulations.

... their mechanism of action is inhibition of adenosine deaminase. Adenosine deaminase deficiency GRCh38: Ensembl release 89: ... Adenosine deaminase (also known as adenosine aminohydrolase, or ADA) is an enzyme (EC 3.5.4.4) involved in purine metabolism. ... Adenosine deaminase deficiency leads to pulmonary fibrosis, suggesting that chronic exposure to high levels of adenosine can ... Blackburn MR (2003). "Too much of a good thing: adenosine overload in adenosine-deaminase-deficient mice". Trends in ...
... adenine nucleotide deaminase, and adenosine (phosphate) deaminase. The EC number for adenosine-phosphate deaminase is [EC 3.5. ... indicates that adenosine-phosphate deaminase binds to 5'-adenosine monophosphate. The pathway for adenosine-phosphate deaminase ... all of them deaminate adenosine, 2'-deoxyadenosine, 5'-AMP, and 3',5'-cyclic AMP. Inhibitors of adenosine-phosphate deaminase ... Adenosine-phosphate deaminase binds to 5'-AMP using water to break the C-N bond and replacing it with a carbonyl group. ...
The enzyme adenosine deaminase is encoded by the ADA gene on chromosome 20. ADA deficiency is inherited in an autosomal ... "Adenosine Deaminase (ADA) Deficiency". Archived from the original on 2008-02-12. Retrieved 2008-02-28. p347, The Immune System ... Adenosine deaminase deficiency (ADA deficiency) is a metabolic disorder that causes immunodeficiency. It is caused by mutations ... Adenosine deaminase deficiency - Genetics Home Reference (Articles with short description, Short description is different from ...
The protein product of this gene, adenosine deaminase 2 (ADA2), is an extracellular enzyme that breaks down adenosine and may ... Carmona-Rivera C (2019). "Deficiency of adenosine deaminase triggers adenosine-mediated NETosis and TNF production in patients ... "The extracellular adenosine deaminase growth factor, ADGF/CECR1, plays a role in Xenopus embryogenesis via the adenosine/P1 ... Aksentijevich I (1993). "Adenosine Deaminase 2 Deficiency". In Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJ, Mirzaa G, ...
Double-stranded RNA-specific adenosine deaminase (EC) converts multiple adenosines to inosines and creates I/U mismatched base ... This family consists of the N-terminus and thus the z-alpha domain of double-stranded RNA-specific adenosine deaminase (ADAR), ... In molecular biology, the protein domain Adenosine deaminase z-alpha domain refers to an evolutionary conserved protein domain ... DRADA has been found to modify adenosines in AU-rich regions more frequently, probably due to the relative ease of melting A/U ...
Adenosine mediates pain through adenosine receptors. MADD causes an increase of free adenosine during heavy activity which may ... Adenosine monophosphate deaminase deficiency type 1 or AMPD1, is a human metabolic disorder in which the body consistently ... AMP deaminase is an enzyme that converts adenosine monophosphate (AMP) to inosine monophosphate (IMP), freeing an ammonia ... In the brain, excess adenosine decreases alertness and causes sleepiness. In this way, adenosine may play a role in fatigue ...
The nucleoside, adenosine, is then deaminated and hydrolyzed to form hypoxanthine via adenosine deaminase and nucleosidase ... "Adenosine deaminase (ADA) deficiency". Learn.Genetics. Archived from the original on 3 November 2014. Retrieved 31 October 2014 ... and adenosine deaminase deficiency, which causes immunodeficiency. Once the nucleotides are synthesized they can exchange ... Guanine is then deaminated via guanine deaminase to form xanthine which is then converted to uric acid. Oxygen is the final ...
APC Adenosine deaminase deficiency, partial; 102700; ADA Adenosine triphosphate, elevated, of erythrocytes; 102900; PKLR ...
When the enzyme adenosine deaminase is deficient in the body, the result is a toxic build-up of metabolites that impair ... ERT has also been used to treat patients with severe combined immunodeficiency (SCID) resulting from an adenosine deaminase ... Many ADA deficient children with SCID have been treated with the polyethylene glycol-conjugated adenosine deaminase (PEG-ADA) ... ERT has also been successful in treating severe combined immunodeficiency caused by an adenosine deaminase deficiency (ADA-SCID ...
"A sensitive radiochemical assay for adenosine deaminase". Clinical Immunology and Immunopathology. 5 (2): 173-176. doi:10.1016/ ...
This enzyme is also called adenosine triphosphate deaminase. Chung ST, Aida K (January 1967). "Purification and properties of ... In enzymology, an ATP deaminase (EC 3.5.4.18) is an enzyme that catalyzes the chemical reaction ATP + H2O ⇌ {\displaystyle \ ... ATP deaminase from Microsporum audouini". J. Biochem. Tokyo. 61 (1): 1-9. PMID 6048966. Portal: Biology v t e (EC 3.5.4, ...
... 1 is an enzyme that in humans is encoded by the AMPD1 gene. Adenosine monophosphate deaminase is an enzyme that ... Adenosine monophosphate deaminase 1 catalyzes the deamination of AMP to IMP in skeletal muscle and plays an important role in ... Sims B, Powers RE, Sabina RL, Theibert AB (1999). "Elevated adenosine monophosphate deaminase activity in Alzheimer's disease ... Dale GL (1989). "Radioisotopic assay for erythrocyte adenosine 5'-monophosphate deaminase". Clin. Chim. Acta. 182 (1): 1-7. doi ...
"Entrez Gene: ADAR Adenosine Deaminase Acting on RNA". Kim U, Wang Y, Sanford T, Zeng Y, Nishikura K (November 1994). "Molecular ... ADAR stands for adenosine deaminase acting on RNA. This article focuses on the ADAR proteins; This article details the ... Samuel CE (2012). Adenosine deaminases acting on RNA (ADARs) and A-to-I editing. Heidelberg: Springer. ISBN 978-3-642-22800-1 ... October 2014). "Adenosine deaminase acting on RNA 1 limits RIG-I RNA detection and suppresses IFN production responding to ...
"Gene therapy for immunodeficiency due to adenosine deaminase deficiency". The New England Journal of Medicine. 360 (5): 447-458 ... such as Wiskott-Aldrich Syndrome She led the first stem cell-based gene therapy trial for patients with adenosine deaminase- ...
When adenosine enters the circulation, it is broken down by adenosine deaminase, which is present in red blood cells and the ... Adenosine deaminase deficiency is a known cause of immunodeficiency. The adenosine analog NITD008 has been reported to directly ... Adenosine is believed to be an anti-inflammatory agent at the A2A receptor. Topical treatment of adenosine to foot wounds in ... Adenosine used as a second messenger can be the result of de novo purine biosynthesis via adenosine monophosphate (AMP), though ...
"Strimvelis for treating adenosine deaminase deficiency-severe combined immunodeficiency". NICE. 7 February 2018. Aiuti A, ... in the gene needed to make an enzyme called adenosine deaminase (ADA). As a result, people lack the ADA enzyme. Because ADA is ... is a medication used to treat severe combined immunodeficiency due to adenosine deaminase deficiency (ADA-SCID). ADA-SCID is a ... recommended marketing approval for its use in children with adenosine deaminase deficiency, for whom no matched HSC donor is ...
Jan 2009). "Gene therapy for immunodeficiency due to adenosine deaminase deficiency". N Engl J Med. 360 (5): 447-458. doi: ... pioneered the first successful use of gene therapy for the treatment of bubble baby born with adenosine deaminase deficiency in ... "Consensus approach for the management of severe combined immune deficiency caused by adenosine deaminase deficiency". J Allergy ...
This gene encodes a member of a subfamily of the adenosine deaminase protein family. The encoded protein may act as a growth ... Zavialov AV, Engström A (2006). "Human ADA2 belongs to a new family of growth factors with adenosine deaminase activity". ... Charlab R, Valenzuela JG, Andersen J, Ribeiro JM (2001). "The invertebrate growth factor/CECR1 subfamily of adenosine deaminase ... factor and have adenosine deaminase activity. It may be responsible for some of the phenotypic features associated with cat eye ...
The use of an inhibitor of adenosine deaminase to increase the half-life of vidarabine has also been tried, and drugs such as ... It is prone to deamination by adenosine deaminase to inosine. This metabolite still possesses antiviral activity, but is 10- ... As you can see from figure 1.1 that it is a stereoisomer of adenosine. It has a half-life of 60 minutes, and its solubility is ... This is where ara-ATP is incorporated into the DNA strand replacing many of the adenosine bases. This results in the prevention ...
These include adenosine deaminase 2 deficiency and haploinsufficiency of A20. According to the size of the vessel affected, ... Meyts, Isabelle; Aksentijevich, Ivona (July 2018). "Deficiency of Adenosine Deaminase 2 (DADA2): Updates on the Phenotype, ...
Four-year-old Ashanti DeSilva received treatment for a genetic defect that left her with adenosine deaminase deficiency (ADA- ... The allele that codes for adenosine deaminase (ADA) was obtained and inserted into a retrovirus. Retroviruses and stem cells ... This treats children born with adenosine deaminase deficiency and who have no functioning immune system. This was the second ... Ferrua F, Brigida I, Aiuti A (December 2010). "Update on gene therapy for adenosine deaminase-deficient severe combined ...
"Autologous Ex Vivo Lentiviral Gene Therapy for Adenosine Deaminase Deficiency". The New England Journal of Medicine. 384 (21): ...
... and used a retrovirus to insert a healthy adenosine deaminase (ADA) gene into them. These cells were then injected back into ... in which the patient is injected with polyethyleneglycol-coupled adenosine deaminase (PEG-ADA), which metabolizes the toxic ... "Autologous Ex Vivo Lentiviral Gene Therapy for Adenosine Deaminase Deficiency". New England Journal of Medicine. 384 (21): 2002 ...
Patients with adenosine deaminase deficiency (ADA) tend to have elevated intracellular dATP concentrations because adenosine ... Adenosine triphosphate (ATP) Adenosine deaminase deficiency (ADA) Dilated cardiomyopathy (DCM) Romaniuk PJ, Eckstein F (July ... Cowan MJ, Wara DW, Ammann AJ (October 1985). "Deoxycytidine therapy in two patients with adenosine deaminase deficiency and ... deaminase normally curbs adenosine levels by converting it into inosine. Deficiency of this deaminase also causes ...
RNA-editing deaminase-2 (RED2, or ADARB2) is a member of the double-stranded RNA (dsRNA) adenosine deaminase family of RNA- ... "Entrez Gene: ADARB2 adenosine deaminase, RNA-specific, B2 (RED2 homolog rat)". Hong HQ, Lin JS, Chen L (Feb 2015). "Regulatory ... Chen CX, Cho DS, Wang Q, Lai F, Carter KC, Nishikura K (May 2000). "A third member of the RNA-specific adenosine deaminase gene ... Valenzuela A, Blanco J, Callebaut C, Jacotot E, Lluis C, Hovanessian AG, Franco R (Apr 1997). "Adenosine deaminase binding to ...
It is deaminated intracellularly by adenosine deaminase to dioxolane guanine (DXG). DXG-triphosphate, the active form of the ... Tenofovir is an acyclic adenosine derivative. The acyclic nature of the compound and its phosphonate moiety are unique ... First it is monophosphorylated by adenosine phosphotransferase and then the monophosphate is converted to carbovir 3´- ... In 1964 dideoxyadenosine, the corresponding adenosine analogue of zalcitabine was synthesised. Dideoxyadenosine caused kidney ...
Adenosine deaminase (ADA), an enzyme acting on isolated adenosine GRCh38: Ensembl release 89: ENSG00000197381 - Ensembl, May ... "Entrez Gene: ADARB1 adenosine deaminase, RNA-specific, B1 (RED1 homolog rat)". Macbeth MR, Schubert HL, Vandemark AP, Lingam AT ... Yang JH, Sklar P, Axel R, Maniatis T (April 1997). "Purification and characterization of a human RNA adenosine deaminase for ... Valenzuela A, Blanco J, Callebaut C, Jacotot E, Lluis C, Hovanessian AG, Franco R (April 1997). "Adenosine deaminase binding to ...
Other names in common use include adenosine diphosphate deaminase, and adenosinepyrophosphate deaminase. Deutsch A, Nilsson R ( ... In enzymology, an ADP deaminase (EC 3.5.4.7) is an enzyme that catalyzes the chemical reaction ADP + H2O ⇌ {\displaystyle \ ... 1954). "On the dephosphorylation and deamination of adenosine triphosphate by actomyosin gel". Acta Chem. Scand. 8: 1898-1906. ...
... then adenosine deaminase creates inosine Alternatively, AMP deaminase creates inosinic acid, then a nucleotidase creates ... Some of the diseases are: Severe immunodeficiency by loss of adenosine deaminase. Hyperuricemia and Lesch-Nyhan syndrome by the ... and fifth step are catalyzed by trifunctional purine biosynthetic protein adenosine-3, which is encoded by the GART gene. Both ... catalyzes the oxidation of xanthine to uric acid A nuclease frees the nucleotide A nucleotidase creates adenosine, ...
... and within a million base pairs of the adenosine deaminase locus. It was also found to have an increase in expression in cells ... "Adenosine deaminase: characterization and expression of a gene with a remarkable promoter". EMBO J. 4 (2): 437-43. doi:10.1002/ ...
... their mechanism of action is inhibition of adenosine deaminase. Adenosine deaminase deficiency GRCh38: Ensembl release 89: ... Adenosine deaminase (also known as adenosine aminohydrolase, or ADA) is an enzyme (EC 3.5.4.4) involved in purine metabolism. ... Adenosine deaminase deficiency leads to pulmonary fibrosis, suggesting that chronic exposure to high levels of adenosine can ... Blackburn MR (2003). "Too much of a good thing: adenosine overload in adenosine-deaminase-deficient mice". Trends in ...
Adenosine deaminase (ADA) deficiency is an inherited disorder that damages the immune system and causes severe combined ... medlineplus.gov/genetics/condition/adenosine-deaminase-deficiency/ Adenosine deaminase deficiency. ... mediated immunosuppression and the role of adenosine in causing the immunodeficiency associated with adenosine deaminase ... Adenosine deaminase deficiency is caused by mutations in the ADA gene. This gene provides instructions for producing the enzyme ...
Bethyl Laboratories Anti-ADA/Adenosine Deaminase Polyclonal, Catalog # A305-182A-T. Tested in Western Blot (WB) and ... Cite ADA/Adenosine Deaminase Polyclonal Antibody. The following product was used in this experiment: ADA/Adenosine Deaminase ... ADA/Adenosine Deaminase Antibody (A305-182A-T) in WB Detection of human ADA by western blot. Samples: Whole cell lysate (50 µg ... Plays an important role in purine metabolism and in adenosine homeostasis. Modulates signaling by extracellular adenosine, and ...
Labshub completely concentrates on constant progress and monitoring ensures that we can deliver all assistance at a consistently high-quality level, via our disciplined and automated processes, which is why we are here 24/7 and 365 days for your services. ...
Affected infants present: recurrent chronic viral, fungal, protozoal, and bacterial infections and frequently present with persistent diarrhoea, failure to thrive and candidiasis. Severely affected cases present neonatally with no detectable lymphocytes in peripheral blood or bone marrow and both cell-mediated and humoral immunity is defective. Some patients have had associated bony and hair growth abnormalities and occasionally non-specific neurological disorders, attributed to malnutrition or viral infection.There are two forms of ADA deficiency, complete ADA deficiency with associating immunodeficiency (B-T cell CD4- lympho and thrombopenia), skeletal dysplasia, recurrent respiratory infections and asthma, hepatosplenomegaly and partial ADA deficiency with slow progressive or late onset ...
... manifest non-immunologic symptoms including pulmonary dysfunction likely attributable to elevated systemic adenosine levels. ... Adenosine deaminase-deficient severe combined immunodeficiency (ADA-SCID) is characterized by impaired T-, B- and NK-cell ... Adenosine-dependent pulmonary fibrosis in adenosine deaminase-deficient mice. J Immunol. 2005;175(3):1937-46. ... Adenosine deaminase (ADA) deficiency is among the most severe forms of PIDs, leading to severe combined immunodeficiency (SCID ...
Adenosine deaminase (ADA) deficiency - Lymphopenia occurs from the death of T and B cells secondary to the accumulation of ... Management options for adenosine deaminase deficiency; proceedings of the EBMT satellite workshop (Hamburg, March 2006). Clin ... ADA = adenosine deaminase; BCR = B-cell receptor; JAK = Janus-associated kinase; MHC = major histocompatibility complex; RAG = ... Gene therapy for immunodeficiency due to adenosine deaminase deficiency. N Engl J Med. 2009 Jan 29. 360(5):447-58. [QxMD ...
ADA, adenosine deaminase; AFB, acid-fast bacilli; ATT, anti-TB therapy; CT, computed tomography image; CXR, plain chest ...
Homo sapiens adenosine deaminase isoform 1 (HsADA1) hydrolyzes adenosine and 2-deoxyadenosine as a key step in the purine ... Optimized expression and purification of a human adenosine deaminase in E. coli and characterization of its Asp8Asn variant. ... Optimized expression and purification of a human adenosine deaminase in E. coli and charac ...
View and buy high purity products active at Deaminases from Tocris Bioscience. ... Adenosine deaminases (ADA) irreversibly convert adenosine into inosine by the removal of an amino group and they are necessary ... two well known members of this group are adenosine deaminase and cytidine deaminase. ... They are usually named after their substrate and two well known members of this group are adenosine deaminase (E.C. 3.5.4.4) ...
Adenosine deaminase see SCID (Severe Combined Immunodeficiency) by T. Wood AMH (Anti Mullerian Hormone and Receptor - cryptic ...
ADA = adenosine deaminase; BCR = B-cell receptor; JAK = Janus-associated kinase; MHC = major histocompatibility complex; RAG = ... Management options for adenosine deaminase deficiency; proceedings of the EBMT satellite workshop (Hamburg, March 2006). Clin ... ADA = adenosine deaminase; BCR = B-cell receptor; JAK = Janus-associated kinase; MHC = major histocompatibility complex; RAG = ... Gene therapy for immunodeficiency due to adenosine deaminase deficiency. N Engl J Med. 2009 Jan 29. 360(5):447-58. [QxMD ...
... which was completely reversed by the A1 adenosine receptor antagonist 8-cyclopentyltheophylline and adenosine deaminase. PD ... Selective potentiation by an A1 adenosine receptor enhancer of the negative dromotropic action of adenosine in the guinea pig ... Selective potentiation by an A1 adenosine receptor enhancer of the negative dromotropic action of adenosine in the guinea pig ... Selective potentiation by an A1 adenosine receptor enhancer of the negative dromotropic action of adenosine in the guinea pig ...
ADAR, RNA-specific adenosine deaminase; IRF, IFN-regulatory factor; JAK, Janus kinase; Mx, myxovirus-resistance proteins; OAS, ... A recently discovered IFN-induced gene is the RNA-specific adenosine deaminase ADAR 23although its potential antiviral function ... USA 99 , - Patterson, J. Mechanism of interferon action: double-stranded RNA-specific adenosine deaminase from human cells is ... Vaccinia virus E3L interferon resistance protein inhibits the interferon-induced adenosine deaminase A-to-I editing activity. ...
Recently, adenosine deaminase, a host enzyme produced by activated T cells and easily detected by a colorimetric procedure, was ...
Chromosome 20: gene for adenosine deaminase, Matt Ridley. Matt Ridley talks about chromosome 20, gene for adenosine deaminase. ...
Adenosine deaminase deficiency Adenosine deaminase converts adenosine and deoxyadenosine to inosine and deoxyinosine, which are ... Myoadenylate deaminase deficiency (or muscle adenosine monophosphate deaminase deficiency) The enzyme myoadenylate deaminase ... Treatment of adenosine deaminase deficiency is by bone marrow or stem cell transplantation and enzyme replacement therapy. ... Immune cells are especially sensitive to this defect; adenosine deaminase deficiency causes one form of severe combined ...
The bacterial tRNA adenosine deaminase (TadA) generates inosine by deaminating the adenosine residue at the wobble position of ... Crystal structure of tRNA adenosine deaminase (TadA) from Aquifex aeolicus.. *. Kuratani M, Ishii R, Bessho Y, Fukunaga R, ... This is the first structure of a deaminase acting on tRNA. A. aeolicus TadA has an alpha/beta/alpha three-layered fold and ... but is similar to the dimeric structure of yeast cytosine deaminase. However, in the A. aeolicus TadA structure, the shapes of ...
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Adenosine deaminase deficiency, unspecified. *. Severe combined immunodeficiency due to adenosine deaminase deficiency ...
Severe Combined Immunodeficiency (SCID). SCID with Adenosine Deaminase. Deficiency. Wiskott-Aldrich Syndrome. X-Linked ...
Adenosine Deaminase Deficiency (SCID). *Bare Lymphocyte Syndrome (SCID). *Chediak-Higashi Syndrome (SCID) ...
adenosine deaminase [Source:HGNC Sym.... M15205_at. 7083. TK1. thymidine kinase 1 [Source:HGNC Symb.... ...
ADA Levels (Adenosine Deaminase Test). Adreno Corticotrophic Hormone (ACTH). 24 hrs Urine AFB. AFB culture Conventional Method ...
... as were the results of adenosine deaminase testing. Rheumatoid tests were also performed: anti-double-stranded DNA results were ...
  • Adenosine deaminase deficiency leads to pulmonary fibrosis, suggesting that chronic exposure to high levels of adenosine can exacerbate inflammation responses rather than suppressing them. (wikipedia.org)
  • Adenosine deaminase (ADA) deficiency is an inherited disorder that damages the immune system and causes severe combined immunodeficiency (SCID). (medlineplus.gov)
  • Adenosine deaminase deficiency is very rare and is estimated to occur in approximately 1 in 200,000 to 1,000,000 newborns worldwide. (medlineplus.gov)
  • Adenosine deaminase deficiency is caused by mutations in the ADA gene. (medlineplus.gov)
  • Adenosine deaminase deficiency: unanticipated benefits from the study of a rare immunodeficiency. (medlineplus.gov)
  • In addition, one individual was reported with late-onset adenosine deaminase (ADA) deficiency (ADA-SCID) who had a normal newborn screening test early on. (primaryimmune.org)
  • Two cases of severe combined immunodeciency caused by Adenosine deaminase deficiency. (lasid.org)
  • Introduction: Adenosine deaminase (ADA) deficiency is a common form of severe combined immunodeficiency (SCID). (lasid.org)
  • Adenosine deaminase (ADA) deficiency is among the most severe forms of PIDs, leading to severe combined immunodeficiency (SCID) and susceptibility to severe and recurrent opportunistic infections. (biomedcentral.com)
  • Treatment of myoadenylate deaminase deficiency is exercise modulation as appropriate. (msdmanuals.com)
  • Diagnosis of adenosine deaminase deficiency is by DNA analysis. (msdmanuals.com)
  • Treatment of adenosine deaminase deficiency is by bone marrow or stem cell transplantation and enzyme replacement therapy. (msdmanuals.com)
  • Adenosine deaminase-deficient severe combined immunodeficiency (ADA-SCID) is characterized by impaired T-, B- and NK-cell function. (biomedcentral.com)
  • 5'-monophosphate deaminase from Streptomyces murinus, D-allulose 3-epimerase from Arthrobacter globiformis expressed in Escherichia coli , carbohydrate-derived fulvic acid, jagua (genipin-glycine) blue (Jagua blue), lipase from Mucor javanicus and phosphatidylinositol-specific phospholipase C expressed in Pseudomonas fluorescens ). (who.int)
  • It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues. (wikipedia.org)
  • Adenosine deaminases (ADA) irreversibly convert adenosine into inosine by the removal of an amino group and they are necessary for the breakdown of food and turnover of nucleic acids. (tocris.com)
  • Adenosine deaminase converts deoxyadenosine, which can be toxic to lymphocytes, to another molecule called deoxyinosine that is not harmful. (medlineplus.gov)
  • Other members of this group include guanine deaminase (GDA) (converts guanine to xanthine), dCMP deaminase (DCTD) (involved in cytosine metabolism) and porphobilinogen deaminase (PBGD) (involved in heme biosynthesis). (tocris.com)
  • The enzyme myoadenylate deaminase converts AMP to inosine and ammonia. (msdmanuals.com)
  • Adenosine deaminase converts adenosine and deoxyadenosine to inosine and deoxyinosine, which are further broken down and excreted. (msdmanuals.com)
  • Adenosine deaminase (also known as adenosine aminohydrolase, or ADA) is an enzyme (EC 3.5.4.4) involved in purine metabolism. (wikipedia.org)
  • ADA irreversibly deaminates adenosine, converting it to the related nucleoside inosine by the substitution of the amino group by a keto group. (wikipedia.org)
  • The Adenosine Deaminase Serum is a test that is used to measure the ADA. (1mg.com)
  • This gene provides instructions for producing the enzyme adenosine deaminase. (medlineplus.gov)
  • The function of the adenosine deaminase enzyme is to eliminate a molecule called deoxyadenosine, which is generated when DNA is broken down. (medlineplus.gov)
  • Some mutations in the gene for adenosine deaminase cause it not to be expressed. (wikipedia.org)
  • Mutations in the ADA gene reduce or eliminate the activity of adenosine deaminase and allow the buildup of deoxyadenosine to levels that are toxic to lymphocytes. (medlineplus.gov)
  • Additionally, massive numbers of mutations can be introduced by some virus-encoded diversity-generating elements, as well as by host-encoded cytidine/adenine deaminases. (springer.com)
  • 60 known mutations) results in accumulation of adenosine , which is converted to its ribonucleotide and deoxyribonucleotide (dATP) forms by cellular kinases. (msdmanuals.com)
  • Plays an important role in purine metabolism and in adenosine homeostasis. (thermofisher.com)
  • two well known members of this group are adenosine deaminase and cytidine deaminase. (tocris.com)
  • They are usually named after their substrate and two well known members of this group are adenosine deaminase (E.C. 3.5.4.4) and cytidine deaminase (E.C. 3.5.4.5). (tocris.com)
  • Cytidine deaminases convert cytosine and deoxycytosine to uridine and deoxyuridine respectively, and are involved in maintaining the cellular pyrimidine pool. (tocris.com)
  • Catalyzes the hydrolytic deamination of adenosine and 2-deoxyadenosine. (thermofisher.com)
  • Homo sapiens adenosine deaminase isoform 1 (HsADA1) hydrolyzes adenosine and 2-deoxyadenosine as a key step in the purine nucleoside salvage pathway. (bvsalud.org)
  • Deaminases are enzymes that catalyze the hydrolysis of C-NH 2 bonds in amino compounds, producing ammonia. (tocris.com)
  • Affected children, in addition to early onset of infections, manifest non-immunologic symptoms including pulmonary dysfunction likely attributable to elevated systemic adenosine levels. (biomedcentral.com)
  • The substrate, adenosine, is stabilized and bound to the active site by nine hydrogen bonds. (wikipedia.org)
  • The following product was used in this experiment: ADA/Adenosine Deaminase Polyclonal Antibody from Thermo Fisher Scientific, catalog # A305-182A-T. (thermofisher.com)
  • It has also been proposed that ADA, in addition to adenosine breakdown, stimulates release of excitatory amino acids and is necessary to the coupling of A1 adenosine receptors and heterotrimeric G proteins. (wikipedia.org)
  • It has also been recognized that AMP deaminase protein and activity is upregulated in mouse hearts that overexpress HIF-1α, which in part explains the attenuated levels of adenosine in HIF-1α expressing hearts during ischemic stress. (wikipedia.org)
  • Halliday, Loryn , Brogan, Paul , Freestone, Nicholas and Arrigoni, Francesca (2019) Influence of adenosine deaminase 2, on the angiogenic function of blood outgrowth endothelial cells. (kingston.ac.uk)
  • Optimized expression and purification of a human adenosine deaminase in E. coli and characterization of its Asp8Asn variant. (bvsalud.org)
  • Adenosine Deaminase (ADA) is a protein produced by the body that activates the white blood cells to protect the body from infection. (1mg.com)
  • Adenosine Deaminase Sort 2 Lack: Severe Chronic Neutropenia, Lymphoid Infiltration throughout Bone Marrow, along with Inflammatory Functions. (bosutinibinhibitor.com)
  • The new product gained approval in Europe for treatment of adenosine-deaminase severe combined immunodeficiency (ADA-SCID), a rare immune disease in children. (bioprocessintl.com)
  • Adenosine Deaminase (ADA) plays a critical role in purine metabolism and immune function. (jhrlmc.com)
  • cell's main energy source, a molecule called adenosine triphosphate (ATP). (nih.gov)
  • This cancellation was partially blocked by caffeine, antagonist for the adenosine receptors, A 1 AR, A 2a AR and A 3 AR. (elsevierpure.com)
  • In Adenosine Receptors: Pharmacology, Functions and Therapeutic Aspects (pp. 143-164). (elsevierpure.com)
  • Double-stranded RNA deaminase I (ADAR1) contains the Z-DNA binding domain Zalpha. (rcsb.org)
  • instructions for making a protein called RNA-specific adenosine deaminase 1 (ADAR1). (nih.gov)
  • This gene provides instructions for producing the enzyme adenosine deaminase. (medlineplus.gov)
  • gene provides instructions for making an enzyme called adenosine deaminase 2. (nih.gov)
  • gene provides instructions for producing an enzyme called adenosine monophosphate (AMP) deaminase. (nih.gov)
  • The Dual8 strain genomically encodes two mutagenic chimeric proteins: eMutaT7A→G (TadA8e, an adenosine deaminase, fused to T7RNAP) and MutaT7C→ T (rAPOBEC1, a cytidine deaminase, fused to T7RNAP). (belspo.be)
  • These observations suggest that ADA is involved in the MTX-mediated inhibition of inflammatory bone destruction regulated by adenosine and dAdo. (elsevierpure.com)
  • By providing specific and direct replacement of the adenosine deaminase enzyme, Revcovi can reduce patients' risk of potentially serious, life-threatening infections and their debilitating complications. (medscape.com)
  • In our previous study, plasma adenosine level was markedly increased during induction of inflammation in rats with adjuvant-induced arthritis (arthritic rats). (elsevierpure.com)
  • elevated red cell adenosine deaminase. (nih.gov)
  • Elapegademase -lvlr is a new injectable PEGylated recombinant adenosine deaminase (rADA) enzyme that supplements ADA levels and does not need to be sourced from animals. (medscape.com)