| OAS | old age security; oral allergy syndrome; osmotically active substance |
|---|---|
| OAW | oral airways |
| OC | obstetrical conjugate; occlusocervical; office call; on call; only child; optic chiasma; oral contra... |
| OCA | oculocutaneous albinism; olivopontocerebellar atrophy; oral contraceptive agent |
| OCC | object-centered coordinate [method]; oral cholecystography |
| neoplasms, multiple primary | Two or more abnormal growths of tissue occurring simultaneously. The neoplasms are histologically different and may be found in the same or different sites. (12 Dec 1998) |
|---|---|
| drug resistance, multiple | Simultaneous resistance to a broad spectrum of structurally and functionally distinct drugs following exposure to a single agent. It is thought to result from the overexpression of genes encoding an integral plasma membrane protein, p-glycoprotein. (12 Dec 1998) |
| exostoses, multiple hereditary | Hereditary disorder transmitted by an autosomal dominant gene and characterised by multiple exostoses (multiple osteochondromas) near the ends of long bones. The genetic abnormality results in a defect in the osteoclastic activity at the metaphyseal ends of the bone during the remodeling process in childhood or early adolescence. The metaphyses develop benign, bony outgrowths often capped by cartilage. A small number undergo neoplastic transformation. (12 Dec 1998) |
| familial multiple endocrine adenomatosis | The presence of functioning tumours in more than one endocrine gland, commonly the pancreatic islets and parathyroid glands, which may be associated with Zollinger-Ellison syndrome; dominant inheritance. Synonym: multiple endocrine adenomatosis. (05 Mar 2000) |
| law of multiple proportions | The relative weights in which two substances form a chemical union singly with a third are the same as, or simple multiples of, those in which they unite with each other; a corollary of the law of definite proportions. Synonym: law of multiple proportions. (05 Mar 2000) |
| lipomatosis, multiple symmetrical | Multiple circumscribed or encapsulated lipomas which may be distributed symmetrically or haphazardly or which may form a collar around the neck. (12 Dec 1998) |
| antiberiberi vitamin | A member of the water-soluble B vitamin group, necessary for energy production and carbohydrate metabolism. Deficiency is known as beriberi. (27 Sep 1997) |
| antihemorrhagic vitamin | <biochemistry> A fat soluble vitamin that plays an important role in blood clotting. (27 Sep 1997) |
| antineuritic vitamin | A member of the water-soluble B vitamin group, necessary for energy production and carbohydrate metabolism. Deficiency is known as beriberi. (27 Sep 1997) |
| antiscorbutic vitamin | <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) |
| antisterility vitamin | <biochemistry> Functions as an antioxidant, binds oxygen free radicals that can cause tissue damage, may also play a protective role in the coronary arteries from the damaging effects of cholesterol. (27 Sep 1997) |
| b-complex vitamin | <biochemistry> A group of vitamins that includes: B1(thiamin), B2 riboflavin), B3 (niacin), B6(pyridoxine), B12 (cobalamin) and folate. (24 Mar 1998) |
| vitamin | <biochemistry> An essential low molecular weight organic compound required in trace amounts for normal growth and metabolic processes. They usually serve as components of coenzyme systems. For humans Vitamin A, the B series, C, D1 and D2, E and K are required. Deficiencies of one or more vitamins in the nutrient supply result in deficiency diseases. (11 Nov 1997) |
| vitamin A | <biochemistry> Deficiency of this vitamin interferes with the production of rhodopsin in the eye resulting in night blindness and xerophthalmia. (27 Sep 1997) |
| vitamin A1 | Vitamin A1alcohol; 2,6,6-trimethyl-1-(9'-hydroxy-3',7'-dimethylnona-1',3',5',7'-tetraenyl)cyclohex-1-ene;a half-carotene bearing the b (or beta-ionone) form of the cyclic end group and a CH2OH at the C-15 position (numbering as in carotenoids) or 9'-position (numbering as a nonyl side chain on a cyclohexene ring); an intermediate in the vision cycle, it also plays a role in growth and differentiation. See: dehydroretinol. Synonym: vitamin A1 alcohol, vitamin A1. Retinol dehydrogenase, an oxidoreductase catalyzing interconversion of retinal and NADH to retinol and NAD+. (05 Mar 2000) |