D factor
| vitamin B12 absorption test | <investigation> This test measures the amount of vitamin B12 in the urine after ingesting a dose of B12. This test evaluates vitamin B12 absorption. The cells in the stomach produce a substance known as intrinsic factor. This substance combines with B12 to allow absorption in the distal ileum. The patient is given a small dose of radioactive B12 which can then be detected in the patients urine. Pernicious anaemia is the clinical result of B12 deficiency. Conditions that can result in an abnormal Schilling test include: deficiency of intrinsic factor, malabsorption or the development of an antibody to intrinsic factor. The Schilling test can be performed with or without administration of intrinsic factor to determine what the underlying cause for pernicious anaemia. Laxative use, renal insufficiency and hypothyroidism can all interfere with the results of this test. (27 Sep 1997) |
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| vitamin B12 deficiency | A form of anaemia (low red blood cell counts) that results when the bone marrow fails to produce adequate numbers of red blood cells due to a deficiency in vitamin B12. Intrinsic factor, necessary for normal B12 absorption, may be the underlying cause for B12 deficiency if is not produced in the gastric glands (in the stomach). (27 Sep 1997) |
| vitamin b 12 deficiency | A nutritional condition produced by a deficiency of vitamin b 12 in the diet, characterised by megaloblastic anaemia. Since vitamin b 12 is not present in plants, humans have obtained their supply from animal products, from multivitamin supplements in the form of pills, and as additives to food preparations. A wide variety of neuropsychiatric abnormalities is also seen in vitamin b 12 deficiency and appears to be due to an undefined defect involving myelin synthesis. (12 Dec 1998) |
| vitamin B12 neuropathy | A subacute or chronic disorder of the spinal cord, such as that occurring in certain patients with vitamin B12 deficiency, characterised by a slight to moderate degree of gliosis in association with spongiform degeneration of the posterior and lateral columns. Synonym: combined sclerosis, combined system disease, funicular myelitis, Putnam-Dana syndrome, vitamin B12 neuropathy. (05 Mar 2000) |
| vitamin B12 with intrinsic factor concentrate | A combination of vitamin B12 with suitable preparations of the mucosa of the stomach or intestine of domestic animals used for food by humans. (05 Mar 2000) |
| vitamin B1 hydrochloride unit | The antineuritic activity of 0.003 mg of the standard crystalline vitamin B1 hydrochloride. Synonym: vitamin B1 hydrochloride unit. (05 Mar 2000) |
| vitamin B2 | <biochemistry> Member of the water soluble B vitamin group, important in energy production and the production of red blood cells (27 Sep 1997) |
| vitamin B2 unit | Potency usually expressed in terms of weight of pure riboflavin. See: Sherman-Bourquin unit of vitamin B2. Synonym: vitamin B2 unit. (05 Mar 2000) |
| vitamin B3 | <biochemistry> Member of the water soluble B vitamin group, used in the production of fatty acids, steroids and cholesterol, deficiency is known as pellagra. Has cholesterol-lowering and vasodilating properties. (27 Sep 1997) |
| vitamin B4 | Once believed to be a factor necessary for nutrition of the chick, now identified simply as certain essential amino acids and/or adenine, obsolete term for adenine. (05 Mar 2000) |
| vitamin B5 | Once used to describe biological activities now ascribed to pantothenic acid or nicotinic acid. (05 Mar 2000) |
| vitamin B6 | <biochemistry> Member of the water soluble B vitamin group. Vitamin B6 or pyridoxine, is active in the metabolism of proteins, carbohydrates and fats. It is also a necessary part of haemoglobin synthesis. B6 deficiency results in retarded growth and a peripheral neuropathy. (27 Sep 1997) |
| vitamin B6 deficiency | Member of the water soluble B vitamin group. Vitamin B6 or pyridoxine, is active in the metabolism of proteins, carbohydrates and fats. It is also a necessary part of haemoglobin synthesis. B6 deficiency results in retarded growth and a peripheral neuropathy. (27 Sep 1997) |
| vitamin B6 unit | Potency expressed in terms of weight of pure crystalline pyridoxine. (05 Mar 2000) |
| vitamin B7 | <biochemistry> This vitamin is necessary for the synthesis of various enzymes and actsto reduce blood cholesterol. Adeficiency in this vitamin causes pellagra, which is characterised bydermatitis, diarrhoea, and inflammation of the mucous membranes. (09 Oct 1997) |