| thromb- | See: thrombo-. (05 Mar 2000) |
|---|---|
| thrombase | <enzyme> Protease (34 kD) generated in blood clotting that acts on fibrinogen to produce fibrin. Consists of two chains, A and B, linked by a disulphide bond. B chain has sequence homology with pancreatic serine proteases: cleaves at Arg Gly. Thrombin is produced from prothrombin by the action either of the extrinsic system (tissue factor + phospholipid) or, more importantly, the intrinsic system (contact of blood with a foreign surface or connective tissue). Both extrinsic and intrinsic systems activate plasma factor X to form factor Xa which then, in conjunction with phospholipid (tissue derived or platelet factor 3) and factor V, catalyses the conversion. (18 Nov 1997) |
| thrombasthenia | <haematology> Condition in which there is defective platelet aggregation, though adherence is normal. See: Glanzmann's thrombasthenia. (18 Nov 1997) |
| thrombectomy | Procedure to remove a clot (a thrombus). (12 Dec 1998) |
| thrombelastography | Use of a thrombelastograph, which provides a continuous graphic record of the physical shape of a clot during fibrin formation and subsequent lysis. (12 Dec 1998) |
| thrombi | Plural of thrombus. (05 Mar 2000) |
| thrombin | <enzyme> Protease (34 kD) generated in blood clotting that acts on fibrinogen to produce fibrin. Consists of two chains, A and B, linked by a disulphide bond. B chain has sequence homology with pancreatic serine proteases: cleaves at Arg Gly. Thrombin is produced from prothrombin by the action either of the extrinsic system (tissue factor + phospholipid) or, more importantly, the intrinsic system (contact of blood with a foreign surface or connective tissue). Both extrinsic and intrinsic systems activate plasma factor X to form factor Xa which then, in conjunction with phospholipid (tissue derived or platelet factor 3) and factor V, catalyses the conversion. (18 Nov 1997) |
| thrombin time | Test of the conversion of fibrinogen to fibrin by thrombin in which clotting time of plasma mixed with a thrombin solution is measured. Time is prolonged by afibrinogenaemia, abnormal fibrinogen, or the presence of inhibitory substances, e.g., fibrin-fibrinogen degradation products, heparin. Reptilase, a thrombin-like enzyme unaffected by the presence of heparin, may be used in place of thrombin. (12 Dec 1998) |
| thrombinogen | A coagulation factor needed for the normal clotting of blood. In the cascade of events leading to the final clot, thrombinogen precedes thrombin (and so is a precursor to thrombin). In fact, thrombinogen gives rise to thrombin, and also called prothrombin. (12 Dec 1998) |
| thrombinogenesis | Thrombin production. (05 Mar 2000) |
| thrombo- | Blood clot; coagulation; thrombin. Origin: G. Thrombos, clot (thrombus) (05 Mar 2000) |
| thromboangiitis | Inflammation of the intima of a blood vessel, with thrombosis. Origin: thrombo-+ G. Angeion, vessel, + -itis, inflammation (05 Mar 2000) |
| thromboangiitis obliterans | <disease> A progressive occlusive disease of the blood vessels in the lower extremities. Smoking is considered a major factor in the development and acceleration of this disease. It is autoimmune in nature. Synonym:: Buerger's disease. (15 Oct 1997) |
| thromboarteritis | Arterial inflammation with thrombus formation. (05 Mar 2000) |
| thromboasthenia | <haematology> Condition in which there is defective platelet aggregation, though adherence is normal. See: Glanzmann's thrombasthenia. (18 Nov 1997) |