| ORD | optical rotatory dispersion; oral radiation death |
|---|---|
| OROS | oral osmotic |
| ORT | object relations technique; operating room technician; oral rehydration therapy |
| OS | left eye [Lat. oculus sinister]; occipitosacral; occupational safety; office surgery; Omenn syndrome... |
| OSCC | oral squamous cell carcinoma |
| arachidic acid | CH3(CH2)18COOH;a fatty acid contained in peanut oil, butter, and other fats. Synonym: arachic acid, n-eicosanoic acid, n-icosanoic acid. Origin: Arachis, fr. G. Arakis, leguminous weed (05 Mar 2000) |
|---|---|
| arachidonic acid | <biochemistry> An essential dietary component for mammals. The free acid is the precursor for biosynthesis of prostaglandins, thromboxanes, hydroxyeicosatetraenoic acid derivatives including leucotrienes and is thus of great biological significance. Within cells the acid is found in the esterified form as a major acyl component of membrane phospholipids (especially phosphatidyl inositol) and its release from phospholipids is thought to be the limiting step in the formation of its active metabolites. (18 Nov 1997) |
| arachidonic acid 18-hydroxylase | <enzyme> Converts arachidonic acid to 18-hydroxy-5,8,11,14-eicosatetraenoic acid in the presence of NADPH; cytochrome p450 enzyme Registry number: EC 1.14.13.- Synonym: arachidonic acid 18(r)-hydroxylase, arachidonic acid omega 3-hydroxylase (26 Jun 1999) |
| arachidonic acid cascade | Eicosanoid synthetic pathway. (05 Mar 2000) |
| argininosuccinic acid | <chemical> This amino acid is formed during the urea cycle from citrulline, aspartate and ATP. This reaction is catalyzed by argininosuccinic acid synthetase. Chemical name: L-Aspartic acid, N-(((4-amino-4-carboxybutyl)amino)iminomethyl)-, (S)- (12 Dec 1998) |
| aristolochic acid | 8-Methoxy-6-nitrophenanthro[3,4-d]-1,3-dioxole-5-carboxylic acid;an aromatic bitter derived from plants of the genus Aristolochia. (05 Mar 2000) |
| aromatic d-amino-acid decarboxylase | <enzyme> An enzyme that catalyses the decarboxylation of l-dopa to dopamine, of l-tryptophan to tryptamine, and of l-hydroxytryptophan to serotonin; important in the biosynthetic pathway of catecholamines and melanin. Synonym: dopa decarboxylase, hydroxytryptophan decarboxylase, tryptophan decarboxylase. (05 Mar 2000) |
| aromatic-l-amino-acid decarboxylases | <enzyme> An enzyme group with broad specificity. The enzymes decarboxylate a range of aromatic amino acids including dopa (dopa decarboxylase), tryptophan, and hydroxytryptophan. Chemical name: Aromatic-L-amino-acid carboxy-lyase Registry number: EC 4.1.1.28 (12 Dec 1998) |
| arsanilic acid | An arsenical which has been used as a feed additive for enteric conditions in pigs and poultry. It causes blindness and is ototoxic and nephrotoxic in animals. (4-aminophenyl)-arsonic acid monosodium salt. (12 Dec 1998) |
| arsenic acid | <chemical> The hydrate of arsenic oxide or arsenic pentoxide which forms arsenates with certain bases. (05 Mar 2000) |
| arsenous acid | See: arsenic trioxide. (05 Mar 2000) |
| arsonic acid | A derivative of arsenic acid by replacement of a hydroxyl group by an organic radical. (05 Mar 2000) |
| arylarsonic acid | An arsonic acid containing an aryl radical; e.g., arsenilic acid. (05 Mar 2000) |
| ascorbic acid | <biochemistry> A requisite in the diet of man and guinea pigs. May act as a reducing agent in enzymic reactions, particularly those catalysed by hydroxylases. Synonym: Vitamin C. (18 Nov 1997) |
| ascorbic acid deficiency | A condition due to a dietary deficiency of ascorbic acid (vitamin c), characterised by malaise, lethargy, and weakness. As the disease progresses, joints, muscles, and subcutaneous tissues may become the sites of haemorrhage. Ascorbic acid deficiency frequently develops into scurvy in young children fed unsupplemented cow's milk exclusively during their first year. It develops also commonly in chronic alcoholism. (cecil textbook of medicine, 19th ed, p1177) (12 Dec 1998) |