Document Detail


A primate model (Macaca mulatta) to study the pharmacokinetics of heparin and its fractions.
MedLine Citation:
PMID:  4035364     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have extensively studied the hemostatic parameters and the responses to the anticoagulant action of heparin and its fractions in the primate model (M. mulatta) and found these to be identical to those obtained in humans. The functional properties of antithrombin III, alpha 2-antiplasmin, and platelet factor 4 were also identical to humans in amidolytic and coagulant assays. Human antibodies against FPA, B beta 15-42 peptide, platelet factor 4, and thromboxane B2 reacted with the primate antigen, and assays were developed to measure these parameters in primates. Infusion of activated prothrombin complex concentrates (more than 100 U/kg/day) on a continual basis up to 3 days resulted in a hypercoagulable state manifested by an elevation of FPA, thromboxane B2, and changes in the thrombelastographic patterns. Similarly, infusion of homologous primate serum also resulted in a hypercoagulable state, as was evident by a sharp increase in the FPA levels. The antithrombotic effects of intravenous and subcutaneous administration of heparin, its low molecular fraction, and their constituents were studied after intravenous and subcutaneous injections. The low molecular weight fractions showed the most effective antithrombotic effects, whereas somewhat milder protection was observed with the starting material and highly anionic fraction. The prolongation of global tests, such as the APTT, TT, and changes in the thromboelastogram did not correlate with the reduction in the blood markers of hypercoagulable state. A modified simplate bleeding time method was used to study the effect of heparin and its fractions on the bleeding profile of heparin fractions. The components of fibrinolytic systems were also measurable in both the clot-based and amidolytic methods to predict the profibrinolytic actions of heparin fractions in its mode. These studies suggest that plasma markers, such as the platelet release proteins, products of thrombin activation, and prostaglandin metabolites, may provide better indices in the monitoring of the antithrombotic actions of newer heparins and antithrombotic drugs. Studies suggest that the pathophysiologic responses after a thrombogenic trigger in the primate model are close to humans, and drug modulation of these may provide relevant clinical information. This model provides the most similar preclinical model to study the actions of heparin fractions.
Authors:
J Fareed; A Kumar; A Rock; J M Walenga; P Davis
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Seminars in thrombosis and hemostasis     Volume:  11     ISSN:  0094-6176     ISO Abbreviation:  Semin. Thromb. Hemost.     Publication Date:  1985 Apr 
Date Detail:
Created Date:  1985-09-27     Completed Date:  1985-09-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0431155     Medline TA:  Semin Thromb Hemost     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  138-54     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Antithrombin III / metabolism
Blood Coagulation / drug effects
Blood Coagulation Factors / metabolism
Dogs
Factor X / antagonists & inhibitors
Factor Xa
Female
Fibrinolysis / drug effects
Fibrinopeptide A / metabolism
Heparin / blood,  pharmacology*
Humans
Kinetics
Macaca / blood*
Macaca mulatta / blood*
Male
Models, Biological*
Oligosaccharides / pharmacology
Partial Thromboplastin Time
Prothrombin / antagonists & inhibitors
Prothrombin Time
Rabbits
Thrombin Time
Chemical
Reg. No./Substance:
0/Blood Coagulation Factors; 0/Oligosaccharides; 25422-31-5/Fibrinopeptide A; 9000-94-6/Antithrombin III; 9001-26-7/Prothrombin; 9001-29-0/Factor X; 9002-04-4/Factor IIa; 9005-49-6/Heparin; EC 3.4.21.6/Factor Xa

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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