Accession Number : ADA955155

Title :   Human Platelet Senescence.

Descriptive Note : Annual rept. no. 4, 1 Jan 72-30 Dec 73,

Corporate Author : NEW YORK UNIV MEDICAL CENTER N Y

Personal Author(s) : Karpatkin,Simon

Report Date : 30 DEC 1973

Pagination or Media Count : 4

Abstract : Large-heavy platelets, or megathomnocytes, when compared to small-light platelets have been shown to be more active metabolically and functionally; more resistant to osmotic stress; and kinetically young, as determined via platlet precursor labelling studies with Se75-selenomethionine and by kinetic studies with a thrombopoietic stimulus. Recognition of megathrombocytes has been shown to be useful clinically. Their enumeration can be helpful in the prediction of megakaryocyte number (for turnover), as well as a compensated thrombocytolytic state. Recent published work has been directed towards an attempt to determine the critical rate-limiting steps controlling in vitro platelet senescenced. Work has been directed towards the kinetics of megathrombocyte (large young platelet) production. It was also found that plasma from chronically bled animals as capable of inducing thrombocytosis and megathrombocytosis when injected into recipient animals - indicating the presence of a humoral factor or hormone.

Descriptors :   ANIMALS, BLOOD PLATELETS, IN VITRO ANALYSIS, KINETICS, OSMOSIS, PRODUCTION, RESISTANCE, STRESSES

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE