Platelet size and age determine platelet function independently

摘要: This study was undertaken to examine the interaction of platelet size and age in determining vitro function. Baboon megakaryocytes were labeled vivo by injection 75Se-methionine. Blood collected when label predominantly associated with younger platelets (day 2) older 9). Size-dependent subpopulations prepared on both days counterflow centrifugation. The reactivity each subpopulation determined measuring thrombin-induced aggregation. Platelets fixed after partial aggregation had occurred addition EDTA/formalin. After removal aggregated differential centrifugation, supernatant medium assayed for remaining 75Se radioactivity. Comparing day 2 9, no significant difference seen rate a given subpopulation. However, more rapid larger fractions than smaller ones days. A greater percentage radioactivity appeared aggregates 9. effect independent size, as it similar extent unfractionated size-dependent subpopulations. data indicate that young are active platelets. demonstrates determinants function, but mechanisms.