| corticotropin-releasing factor | <endocrinology, physiology> A neuropeptide released by the hypothalamus that stimulates the release of corticotropin by the anterior pituitary gland. Chemical name: Corticotropin-releasing factor Synonym: corticoliberin, corticotropin releasing factor. (12 Dec 1998) |
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| myocardial depressant factor | A low molecular weight peptide of about 800-1000 having a negative inotropic effect. It is released into the circulation during experimental haemorrhagic pancreatitis, severe ischemia, and postoligaemic shock. (12 Dec 1998) |
| coupling factor | Protein responsible for coupling transmembrane potentials to ATP synthesis in chloroplasts and mitochondria. Include ATP synthesising enzymes (F1 in mitochondrion), that can also act as ATP ases. (18 Nov 1997) |
| Hageman factor | <chemical> Stable blood coagulation factor activated by contact with the subendothelial surface of an injured vessel. Along with prekallikrein, it serves as the contact factor that initiates the intrinsic pathway of blood coagulation. Kallikrein activates factor xii to xiia. Deficiency of factor xii, also called the hageman trait, leads to increased incidence of thromboembolic disease. Chemical name: Blood-coagulation factor XII (12 Dec 1998) |
| Hageman factor assay | A test used to measure the activity of a blood clotting factor XII. This test may be used to evaluate excessive bleeding. Low factor XII may be seen in cases of congenital deficiency of factor XII, heparin administration and liver disease. (27 Sep 1997) |
| hageman factor deficiency | A deficiency of a specific blood clotting factor (XII) that may be genetic or acquired. Administration of heparin or severe liver disease may result in factor XII (Hageman factor) deficiency. There are usually no symptoms associated with this deficiency, but there may be symptoms of mild blood loss in some cases. Treatment is generally unnecessary. Individuals should be cautioned against the use of medications (for example aspirin, warfarin, heparin) with anticoagulant activity, due to risk of exaggerated effects. (27 Sep 1997) |
| Hagemann factor | <haematology> Plasma _ globulin (110 kD), blood clotting factor XII, which is activated by contact with surfaces to form Factor XIIa, that in turn activates factor XI. Factor XIIa also generates plasmin from plasminogen and kallikrein from prekallikrein. Both plasmin and kallikrein activate the complement cascade. Hagemann factor is important both in clotting and activation of the inflammatory process. (18 Nov 1997) |
| safety factor | <radiobiology> The number of times a field line goes around a torus the long way for each time around the short way. In a tokamak, this number is typically near unity in the centre of the plasma and between two and 6 or 8 at the edge. So-called because it helps to determine the degree of stability the plasma has against certain instabilities. The safety factor is the inverse of the rotational transform, and can be expressed mathematically as q = (r Bt)/(R Bp), where r and R are the minor and major radii of the torus, and Bt and Bp are the toroidal and poloidal magnetic fields. (17 Dec 1997) |
| heat-shock factor | <cell biology, protein> A class of molecular chaperones found in both prokaryotes and in several compartments of eukaryotic cells. There is evidence that these proteins can interact with polypeptides during a variety of assembly processes in such a way as to prevent the formation of nonfunctional structures. (12 Dec 1998) Previous: heat-shock factor, heat-shock gene, heat-shock protein, heat-shock protein 27 kinaseNext: heat-shock proteins 90, heat-shock responseheat-shock factor -->heat-shock proteins 90 <cell biology, protein> A class of molecular chaperones whose members act in the mechanism of signal transduction by steroid receptors. (12 Dec 1998) |
| helper factor | A group of factors apparently produced by helper T lymphocytes that act specifically or non-specifically to transfer T-cell help to other classes of lymphocytes. The existence of specific T-cell helper factor is uncertain. (18 Nov 1997) |
| prolactin-inhibiting factor | A substance of hypothalamic origin capable of inhibiting the synthesis and release of prolactin. Synonym: prolactin-inhibiting factor, prolactin-inhibiting hormone. Origin: prolactin + G. Stasis, standing still, + -in (05 Mar 2000) |
| prolactin-releasing factor | A substance of hypothalamic origin that stimulates the release of prolactin. Synonym: prolactin-releasing factor, prolactin-releasing hormone. Origin: prolactin + L. Libero, to free, + -in (05 Mar 2000) |
| properdin factor A | A component of the properdin system; a hydrazine-sensitive b1-globulin (mw about 180,000), now known to be C3 (third component of complement). (05 Mar 2000) |
| properdin factor b | <enzyme> A glycine-rich, heat-labile beta-glycoprotein found in blood. It is a proactivator of complement 3 in the alternate pathway of complement activation. Factor b is converted by factor d to c3 convertase. Registry number: EC 3.4.21.47 (12 Dec 1998) |
| properdin factor d | <enzyme> A serum protein which during the alternate pathway of complement activation converts the inactive properdin factor b to c3 convertase. Registry number: EC 3.4.21.46 (12 Dec 1998) |