| serum prothrombin conversion accelerator | <chemical> Heat- and storage-stable plasma protein that is activated by tissue thromboplastin to form factor viia in the extrinsic pathway of blood coagulation. The activated form then catalyses the activation of factor x to factor xa. Chemical name: Blood-coagulation factor VII (12 Dec 1998) |
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| angiotensin-converting enzyme | <enzyme> This hydrolase enzyme cleaves the decapeptide angiotensin I (biologically inactive) to form active angiotensin II by angiotensin-converting enzyme which removes a dipeptide (histidylleucine) from angiotensin I. Angiotensin II causes contraction of vascular smooth muscle and thus raises blood pressure and stimulates aldosterone release from the adrenal glands. Angiotensin is finally broken down by angiotensinases. Elevations in angiotensin converting enzyme are seen sarcoidosis, histoplasmosis, alcoholic cirrhosis, asbestosis, berylliosis, diabetes, Hodgkin's disease, hyperthyroidism, amyloidosis, primary biliary cirrhosis, idiopathic pulmonary fibrosis, pulmonary embolism, scleroderma, silicosis, tuberculosis, Gaucher's disease and leprosy. The normal values are 18 to 67 U/ml over 20 years of age (people under 20 have higher levels). Drugs that inhibit ACE are used to treat hypertension and congestive heart failure. See: angiotensin-converting enzyme inhibitor Acronym: ACE (12 Aug 2000) |
| angiotensin-converting enzyme inhibitor | <pharmacology> A class of drugs used in the treatment of hypertension and heart failure. They exert their haemodynamic effect mainly by inhibiting the renin-angiotensin system and produce a reduction of peripheral arterial resistance. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. (14 Aug 2000) |
| angiotensin-converting enzyme secretase | <enzyme> Converts ace from a membrane-bound to a soluble form; not inhibited by thiol, serine or acid enzyme inhibitor but is inhibited by edta and 1,10-phenanthroline Registry number: EC 3.4.99.- Synonym: ace secretase (26 Jun 1999) |
| vasopressin-converting aminopeptidase | <enzyme> Activity found in brain which converts vasopressin into centrally active metabolites Registry number: EC 3.4.11.- Synonym: vp-c aminopeptidase (26 Jun 1999) |
| dynorphin-converting endopeptidase | <enzyme> Enzyme from human cerebrospinal fluid; cleaves dynorphin a and b and neoendorphin at the arg(6)-arg(7) or arg(6)-lys(7) bonds Registry number: EC 3.4.21.- Synonym: dynorphin-neo-endorphin endopeptidase, dc-endopeptidase (26 Jun 1999) |
| interleukin-1 converting enzyme | <biochemistry> Cytoplasmic cysteine protease that is uniquely responsible for cleaving proIL-1_ (31 or 33 kD) into mature IL-1_ (17.5 kD), the active cytokine is then released by a nonstandard mechanism (there is no signal sequence and it does not pass through the Golgi). The enzyme seems to be composed of two nonidentical subunits derived from a single proenzyme. The ICE gene has some homology with the ced 9 gene of C. Elegans, the product of which is involved in mediating cell death by apoptosis. (11 Mar 1998) |
| urokinase-converting protease | <enzyme> Degrades synthetic urokinase substrates and stimulates urokinase Registry number: EC 3.4.21.- Synonym: urokinase cofactor (26 Jun 1999) |
| proserum prothrombin conversion accelerator | A coagulation (clotting) factor. Classic haemophilia (haemophilia A) is due to a congenital deficiency in the amount (or activity) of factor VIII. Factor VIII is also known as antihemophiliac factor (AHF) or antihemophiliac globulin (AHG). The gene for factor VIII (that for classic haemophilia) is on the X chromosome so females can be silent carriers without symptoms and males can be haemophiliacs. (12 Dec 1998) |
| prothrombin | Clotting Factor II. Origin: Gr. Thrombos = cloth in (18 Nov 1997) |
| prothrombin accelerator | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| prothrombin and proconvertin test | A test formerly used by some to control anticoagulant therapy with bishydroxycoumarin and indandione drugs. Synonym: P and P test. (05 Mar 2000) |
| prothrombin deficiency | A congenital or acquired disorder of blood clotting where there is a deficiency of factor II (prothrombin), one of 20 necessary plasma proteins for normal blood coagulation. Acquired factor II deficiency may result from vitamin K deficiency, severe liver disease and anticoagulant drugs. Symptoms include abnormal bleeding, nosebleeds, abnormal menstrual bleeding, easy bruising and umbilical cord bleeding at birth. Treatment involves the infusion of fresh frozen plasma. Vitamin K may be administered in select cases. (27 Sep 1997) |
| prothrombin test | A quantitative test for prothrombin in the blood based on the clotting time of oxalated blood plasma in the presence of thromboplastin and calcium chloride; measures the integrity of the extrinsic and common pathways of coagulation. See: prothrombin time. Synonym: Quick's method, Quick's test. (05 Mar 2000) |
| prothrombin time | Measurement of clotting time of plasma recalcified in the presence of excess tissue thromboplastin. Factors measured are fibrinogen, prothrombin, and factors v, vii, and x. It is used for monitoring anticoagulant therapy with coumarins. (12 Dec 1998) |