| antihemophilic factor B | <chemical> Storage-stable blood coagulation factor acting in the intrinsic pathway. Its activated form, ixa, forms a complex with factor viii and calcium on platelet factor 3 to activate factor x to xa. Deficiency of factor ix results in christmas disease (haemophilia b). Chemical name: Blood-coagulation factor IX (12 Dec 1998) |
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| antihemorrhagic factor | <biochemistry> A fat soluble vitamin that plays an important role in blood clotting. (27 Sep 1997) |
| antineuritic factor | A member of the water-soluble B vitamin group, necessary for energy production and carbohydrate metabolism. Deficiency is known as beriberi. (27 Sep 1997) |
| antinuclear factor | A factor, usually antibodies, present in serum with strong affinity for nuclei and detected by fluorescent antibody technique; present in lupus erythematosus, rheumatic arthritis, and certain other autoimmune conditions; may also be present at lower levels in normal individuals. (05 Mar 2000) |
| antipellagra factor | A precursor of NAD, that is a product of the oxidation of nicotine. (18 Nov 1997) |
| antipernicious anaemia factor | <biochemistry> Member of the water soluble B vitamin group, important in the proper function of the nervous system and important in proper carbohydrate, protein and fat metabolism. (27 Sep 1997) |
| antisterility factor | <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) |
| antitermination factor | <molecular biology> A gene regulatory protein that blocks signals for the transcription process to stop as a form of regulatory control over whatever the gene being transcribed is coding for. (13 Jan 1998) |
| atrial natriuretic factor | <chemical> A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight peptides derived from a common precursor and secreted by the heart atria. All these peptides share a sequence of about 20 amino acids. Chemical name: Atriopeptin (12 Dec 1998) |
| attenuation factor | <radiobiology> A measure of the opacity of a layer of material for radiation transversing it, the ratio of the incident intensity to the transmitted intensity. It is equal to Io/I, where Io and I are the intensities of the incident and emergent radiation, respectively. In the usual sense of exponential absorption (I = Ioe- m x), the attenuation factor is e- m x, where x is the thickness of the material and m is the absorption coefficient. (16 Dec 1997) |
| autocrine motility factor | A member of the class of cytokines secreted by tumour cells. It elicits increases in cell motility and phosphoinositide metabolism in the secreting or producing cell via a pertussis toxin-sensitive g-protein signal transduction pathway. The factor has also been used as a marker for bladder cancer. (12 Dec 1998) |
| B-cell differentiating factor | <cytokine> A soluble cytokine factor produced by activated T-lymphocytes that promotes antibody production by causing proliferation and differentiation of B-cells. Interleukin-4 induces the expression of class II major histocompatibility complex and fc receptors on B-cells. It also acts on T-lymphocytes, mast cell lines, and several other haematopoietic lineage cells including granulocyte, megakaryocyte, and erythroid precursors, as well as macrophages. Acronym: IL-4 (12 Dec 1998) |
| B-cell stimulatory factor 2 | <cytokine> A cytokine that stimulates the growth and differentiation of human B-cells and is also a growth factor for hybridomas and plasmacytomas. It is produced by many different cells including T-cells, monocytes, and fibroblasts. A single chain 25 kD cytokine originally described as a pre B-cell growth factor, now known to have effects on a number of other cells including T-cells which are also stimulated to proliferate. An inducer of acute phase proteins and a colony-stimulating factor acting on mouse bone marrow. Acronym: IL-6 (12 Dec 1998) |
| bifidus factor | An unidentified substance associated with Lactobacillus bifidus subsp. Pennsylvanicus, present in mammalian milk. (05 Mar 2000) |
| bioaccumulation factor | Concentration of a chemical in living tissue divided by its concentration in the animal's diet. (09 Oct 1997) |