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Related to thromboplastin: Prothrombin time


see blood clottingblood clotting,
process by which the blood coagulates to form solid masses, or clots. In minor injuries, small oval bodies called platelets, or thrombocytes, tend to collect and form plugs in blood vessel openings.
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The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(Factor III), an important coagulation factor in the blood-clotting system; it helps convert prothrombin into thrombin. Thromboplastin is localized in the membranes of formed elements of the blood and in the cells of various organs. A large amount of thromboplastin enters the blood upon injury to tissues. Brain and lung tissues have especially high thrombo-plastic activity, and lung thromboplastin also takes part in the metabolism of the vasoactive polypeptides angiotensin and bradykinin.

Chemically, thromboplastin is a protein-lipid complex. The basis of its activity is its lipid constituent, which contains serine, eth-anolamine, and choline phosphatides. Blood coagulation factors are adsorbed on the phospholipid micelle, creating favorable conditions for the enzymatic reactions involved in blood clotting.

The term “thromboplastin” is sometimes used to designate an active complex that includes, in addition to thromboplastin, a number of protein factors and Ca2+ ions. Such active thromboplastin, which directly converts prothrombin into thrombin, is also called thrombokinase or prothrombinase. Thromboplastin is used in clinical practice to determine the prothrombin level, an indicator of the condition of the blood-clotting system.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


Any of a group of lipid and protein complexes in blood that accelerate the conversion of prothrombin to thrombin. Also known as factor III; plasma thromboplastin component (PTC).
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
PT: Prothrombin time, aPTT: Partial thromboplastin time Table 3: Coagulation profile among blood groups in controls Blood group Frequency (n) PT (in seconds) aPTT (in seconds) A 9 14.56[+ or -]1.78 43.09[+ or -]2.60 B 11 15.16[+ or -]2.03 43.4[+ or -]2.57 AB 8 14.97[+ or -]2.22 43.23[+ or -]2.4 O 22 15.58[+ or -]1.68 44[+ or -]2.44 F value 1.74 0.86 P value 0.17 0.46 Blood group Fibrinogen (in mg/dL) A 276.14[+ or -]22.9 B 275.8[+ or -]24.5 AB 275.2[+ or -]29.8 O 270.7[+ or -]18.08 F value 0.27 P value 0.84 (*) P<0.05 - statistically significant.
Effect of concentration of trisodium citrate anticoagulant on calculation of the International Normalised Ratio and the International Sensitivity Index of thromboplastin. Thromb Haemost.
A prospective study of the value of monitoring heparin treatment with the activated partial thromboplastin time.
The activated partial thromboplastin time (aPTT) is reliably elevated, though with nonlinear pharmacokinetics with dabigatran use, and may be used as a proxy or a screening test in patients suspected to have a bleeding risk [13].
Abbreviations aPTT: Activated partial thromboplastin time CV ICU: Cardiovascular intensive care unit IA: Intra-arterial ICH: Intracranial hemorrhage IV: Intravenous NIHSS: National Institutes of Health Stroke Scale PCI: Percutaneous coronary intervention SCC: Stroke after cardiac catheterization tPA: Tissue plasminogen activator.
The activated partial thromboplastin time (APTT) is a clot-based test of the intrinsic and common coagulation pathways.
These were the activated Partial Thromboplastin Time (aPTT) test which measures the intrinsic pathway of blood coagulation and the Prothrombin Time (PT) test which monitors the tissue factor (extrinsic) pathway of clotting.
The main aim of this study is to assess possible association between prothrombin time and activated partial thromboplastin time with effects of blood pressures in hypertensive and normotensive subjects and their significant utility for screening hemostatic dysfunction in hypertensive patients.
In this study, significant acquired coagulopathy was defined as a platelet count < 100 x [10.sup.9]/l, an international normalised ratio (INR) >1.5, or activated partial thromboplastin time (aPTT) >50 seconds.
In the pooled analysis, ginkgo significantly reduced blood viscosity, but had no significant effect on ADP-induced platelet aggregation, fibrinogen concentration, prothrombin time, or activated partial thromboplastin time.
If his prothrombin time and partial thromboplastin time are abnormal, fresh frozen plasma may help correct a clotting factor deficiency.

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