| factor va | <chemical> Activated form of factor v. It is an essential cofactor for the activation of prothrombin catalyzed by factor xa. Chemical name: Blood-coagulation factor Va (12 Dec 1998) |
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| factor v assay | A test used to measure the activity of a blood clotting factor V. This test may be used to evaluate excessive bleeding. Abnormally low factor V assays may be seen in the following conditions: congenital deficiency of factor V, DIC, heparin administration, cirrhosis and primary fibrinolysis. (27 Sep 1997) |
| factor v deficiency | An inherited disorder that results in abnormal blood clotting due to the deficiency of factor V, one of 20 plasma proteins responsible for the maintenance of normal blood clotting. Symptoms include excessive bleeding, bleeding gums, nosebleeds, easy bruising, excessive menstrual bleeding and bleeding into muscle tissue (haematoma) or a joint space (haemarthrosis). Treatment includes the infusion of fresh frozen plasma to restore deficient factor V. (27 Sep 1997) |
| factor x | <chemical> Storage-stable glycoprotein blood coagulation factor that can be activated to factor xa by both the intrinsic and extrinsic pathways. A deficiency of factor x, sometimes called stuart-prower factor deficiency, may lead to a systemic coagulation disorder. Chemical name: Blood-coagulation factor X (12 Dec 1998) |
| factor xa | <enzyme> Activated form of factor x that participates in both the intrinsic and extrinsic pathways of blood coagulation. It catalyses the conversion of prothrombin to thrombin in conjunction with other cofactors. Registry number: EC 3.4.21.6 (12 Dec 1998) |
| factor x assay | A test used to measure the activity of a blood clotting factor X. This test may be used to evaluate excessive bleeding. Abnormally low factor X assays may be seen in the following conditions: congenital deficiency of factor X, fat malabsorption, heparin administration, cirrhosis, vitamin K deficiency and warfarin administration. (27 Sep 1997) |
| factor x deficiency | Blood coagulation disorder usually inherited as an autosomal recessive trait, though it can be acquired. It is characterised by defective activity in both the intrinsic and extrinsic pathways, impaired thromboplastin time, and impaired prothrombin consumption. (12 Dec 1998) |
| factor X for Haemophilus | <physiology> A substance, in the form of reddish brown, microscopic, prismatic crystals, formed from dried blood by the action of strong acetic acid and common salt; called also Teichmann's crystals. Chemically, it is a hydrochloride of haematin. The obtaining of these small crystals, from old blood clots or suspected blood stains, constitutes one of the best evidences of the presence of blood. Origin: Gr. Blood. Source: Websters Dictionary (01 Mar 1998) |
| factor xi | <chemical> Stable blood coagulation factor involved in the intrinsic pathway. The activated form xia activates factor ix to ixa. Deficiency of factor xi is often called haemophilia c. Chemical name: Blood-coagulation factor XI (12 Dec 1998) |
| factor xia | <enzyme> Activated form of factor xi. In the intrinsic pathway, factor xi is activated to xia by factor xiia in the presence of cofactor hmwk (high molecular weight kininogen). Factor xia then activates factor ix to factor ixa in the presence of calcium. Registry number: EC 3.4.21.27 (12 Dec 1998) |
| factor xi deficiency | A deficiency of blood coagulation factor xi (known as plasma thromboplastin antecedent or pta or antihemophilic factor c) resulting in a systemic blood-clotting defect called haemophilia c or rosenthal's syndrome, that may resemble classical haemophilia. (12 Dec 1998) |
| factor xii | <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) |
| factor xiia | <enzyme> Activated form of factor xii. In the initial event in the intrinsic pathway of blood coagulation, kallikrein (with cofactor high molecular weight kininogen) cleaves factor xii to xiia. Factor xiia is then further cleaved by kallikrein, plasmin, and trypsin to yield smaller factor xii fragments (hageman-factor fragments). These fragments increase the activity of prekallikrein to kallikrein but decrease the procoagulant activity of factor xii. Registry number: EC 3.4.21.38 (12 Dec 1998) |
| factor xii 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) |
| factor xii 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) |