| 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) |
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| 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) |
| bioconcentration factor | Concentration of a chemical in an organism divided by its concentration in the test solution or environment (for example, concentration in fish divided by concentration in water). (09 Oct 1997) |
| Bittner's milk factor | Member of the retrovirus subfamily Oncornavirinae, antigenically distinct from the murine leukaemia-sarcoma complex, that is associated with adenocarcinomatous tumours of the mammary gland, commonly latent in wild and laboratory mice and causing cancer only in genetically susceptible strains under certain hormonal influences. Synonym: Bittner agent, Bittner virus, Bittner's milk factor, mammary cancer virus of mice, milk factor, mouse mammary tumour virus. (05 Mar 2000) |
| blood clotting factor | <haematology> Any of a number of different protein factors which, when acting together, can form a blood clot shortly after platelets have broken at the site of the wound. The factors have Roman numeral names, like VII, VIII, IX, X, XI, and XIII. Defects in the genes which code for any of these factors result in genetic diseases like haemophilia, which results from a defect in the gene for factor VIII or IX. (09 Oct 1997) |
| blood coagulation factor inhibitors | Substances, usually endogenous, that act as inhibitors of blood coagulation. They may affect one or multiple enzymes throughout the process. As a group, they also inhibit enzymes involved in processes other than blood coagulation, such as those from the complement system, fibrinolytic enzyme system, blood cells, and bacteria. (12 Dec 1998) |
| brain-derived neurotrophic factor | <growth factor> Small basic protein purified from pig brain, a member of the family of neurotrophic factors that also includes Nerve Growth Factor and neurotrophin 3. In contrast to nerve growth factor, brain-derived neurotrophic factor is predominanantly (though not exclusively) localised in the CNS. It supports the survival of primary sensory neurons originating from the neural crest and ectodermal placodes that are not responsive to NGF. In the brain brain-derived neurotrophic factor has a trophic action on retinal, cholinergic, and dopaminergic neurons, and in the peripheral nervous system it acts on both motor and sensory neurons. Acronym: BDGF (12 Dec 1998) |
| branching factor | 1,4-alpha-glucan-branching enzyme. (05 Mar 2000) |
| BT factor | <biochemistry> _ Hydroxy _ trimethyl aminobutyric acid. Compound that transports long chain fatty acids across the inner mitochondrial membrane in the form of acyl carnitine. Sometimes referred to as Vitamin Bt or Vitamin B7. (18 Nov 1997) |
| CAMP factor | A test to identify Group B beta-streptococci based on their formation of a substance (CAMP factor) that enlarges the area of haemolysis formed by streptococcal beta-haemolysin. Origin: Christie, Atkins, and Munch-Petersen, developers of the t. (05 Mar 2000) |
| capacity factor | <physics> This is the ratio of the average power output from an electric power plant to the plant's rated capacity. A capacity factor is ideally unity, but invariably less. Capacity factors vary widely between types of electric plants (for example, nuclear, solar, coal, etc.), and can even vary widely for a single type of power plant. <radiobiology> Index (typically in percent) indicating the average power supplied by an energy plant, relative to its maximum rated capacity. Synonym: plant factor, load factor. (13 Jan 1998) |
| capillary permeability factor | A mixture of bioflavonoids extracted from plants (especially citrus fruits). It reduces the permeability and fragility of capillaries and is useful in the treatment of certain cases of purpura that are resistant to vitamin C therapy. See: hesperidin, quercetin, rutin. Synonym: capillary permeability factor, citrin, permeability vitamin. (05 Mar 2000) |
| galactagogue factor | <endocrinology> A factor in extracts of the posterior lobe of the hypophysis that, by stimulating the smooth muscle of the lobulo-alveolar system of the mammary gland, causes a flow of milk from the nipple. (05 Mar 2000) |