| oral ulcer | A loss of mucous substance of the mouth showing local excavation of the surface, resulting from the sloughing of inflammatory necrotic tissue. It is the result of a variety of causes, e.g., denture irritation, aphthous stomatitis (stomatitis, aphthous), noma, necrotizing gingivitis (gingivitis, necrotizing, ulcerative), toothbrushing, and various irritants. (12 Dec 1998) |
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| oral vestibule | That part of the mouth bounded anteriorly and laterally by the lips and the cheeks, posteriorly and medially by the teeth and/or gums, and above and below by the reflections of the mucosa from the lips and cheeks to the gums. Synonym: vestibulum oris, buccal cavity, vestibule of mouth. (05 Mar 2000) |
| tuberculosis, oral | Tuberculosis of the mouth, tongue, and salivary glands. (12 Dec 1998) |
| florid oral papillomatosis | Diffuse involvement of the lips and oral mucosa with benign squamous papillomas; microscopically, it resembles verrucous carcinoma, but is not invasive or localised to a specific area of the oral mucosa. (05 Mar 2000) |
| leukoedema, oral | A disorder of the buccal mucosa resembling early leukoplakia, characterised by the presence of filmy opalescence of the mucosa in the early stages to a whitish gray cast with a coarsely wrinkled surface in the later stages, associated with intracellular oedema of the spinous or malpighian layer. (12 Dec 1998) |
| leukoplakia, oral | A white patch seen on the oral mucosa. It is considered a premalignant condition and is often tobacco-induced. When evidence of epstein-barr virus is present, the condition is called hairy leukoplakia (leukoplakia, hairy). (12 Dec 1998) |
| lichen planus, oral | Oral lesions accompanying cutaneous lichen planus or often occurring alone. The buccal mucosa, lips, gingivae, floor of the mouth, and palate are usually affected (in a descending order of frequency). Typically, oral lesions consist of radiating white or gray, velvety, threadlike lines, arranged in a reticular pattern, at the intersection of which there may be minute, white, elevated dots or streaks (wickham's striae). (12 Dec 1998) |
| live oral poliovirus vaccine | Inactivated poliovirus vaccine (IPV), an aqueous suspension of inactivated strains of poliomyelitis virus (types 1, 2, and 3) used by injection; has largely been replaced by the oral vaccine. See: Salk vaccine. (05 Mar 2000) |
| acetyl-activating enzyme | A ligase that catalyses the reaction of acetate and CoA and ATP to form AMP, pyrophosphate, and acetyl-CoA. A key step in the activation of acetate. Synonym: acetate thiokinase, acetate-CoA ligase, acetyl-activating enzyme, acetyl-CoA synthetase. (05 Mar 2000) |
| acyl-activating enzyme | <enzyme> Fatty acid thiokinase (long-chain), a ligase forming acyl-CoA, AMP, and pyrophosphate from long-chain fatty acids, ATP, and coenzyme A. Activity is independent of phosphatidylcholine Registry number: EC 6.2.1.3 Synonym: acyl-activating enzyme, dodecanoyl-CoA synthetase, fatty acid thiokinase (long chain), acid-coenzyme a ligase, fatty acid-CoA ligase, acyl-CoA synthetase, acyl-CoA ligase, coash ligase, ciprofibroyl-CoA synthetase, pristanoyl-CoA synthetase, palmityl CoA synthetase, palmitoyl CoA synthetase, palmitoyl CoA ligase, fatty acyl-CoA synthetase, very long chain fatty acid acyl-CoA synthetase, vlcfa acyl-CoA synthetase, nafenopin-CoA ligase, palmitoyl-CoA synthase, faa2 gene product, faa2p protein, vlacs enzyme (26 Jun 1999) |
| adaptive enzyme | Inducible enzyme, an enzyme that can be detected in a growing culture of a microorganism, after the addition of a particular substance (inducer) to the culture medium, but was not detectable prior to the addition and can act on the inducer. A prototype is the beta-galactosidase of Escherichia coli, synthesised upon the addition of various galactosides, whether or not these are good substrates. Compare: constitutive enzyme. Synonym: adaptive enzyme. (05 Mar 2000) |
| allosteric enzyme | <biochemistry, chemistry> A regulatory enzyme whose activity is modified by the noncovalent binding of a particular metabolite at a site (the allosteric site) other than the active site. (09 Oct 1997) |
| amino acid activating enzyme | <enzyme> Enzymes catalyzing the formation of a specific aminoacyl-tRNA from an amino acid and adenosine 5'-triphosphate with the concomitant formation of adenosine 5'-monophosphate and pyrophosphate. Synonym: amino acid activating enzyme, aminoacyl-tRNA ligases. (05 Mar 2000) |
| angiotensin-converting enzyme | <enzyme> This hydrolase enzyme cleaves the decapeptide angiotensin I (biologically inactive) to form active angiotensin II by angiotensin-converting enzyme which removes a dipeptide (histidylleucine) from angiotensin I. Angiotensin II causes contraction of vascular smooth muscle and thus raises blood pressure and stimulates aldosterone release from the adrenal glands. Angiotensin is finally broken down by angiotensinases. Elevations in angiotensin converting enzyme are seen sarcoidosis, histoplasmosis, alcoholic cirrhosis, asbestosis, berylliosis, diabetes, Hodgkin's disease, hyperthyroidism, amyloidosis, primary biliary cirrhosis, idiopathic pulmonary fibrosis, pulmonary embolism, scleroderma, silicosis, tuberculosis, Gaucher's disease and leprosy. The normal values are 18 to 67 U/ml over 20 years of age (people under 20 have higher levels). Drugs that inhibit ACE are used to treat hypertension and congestive heart failure. See: angiotensin-converting enzyme inhibitor Acronym: ACE (12 Aug 2000) |
| angiotensin-converting enzyme inhibitor | <pharmacology> A class of drugs used in the treatment of hypertension and heart failure. They exert their haemodynamic effect mainly by inhibiting the renin-angiotensin system and produce a reduction of peripheral arterial resistance. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. (14 Aug 2000) |