title: Evidence for appearance of "lysis independent" procoagulant activities in collagen or thrombin stimulated platelets.
abstract: The availability of procoagulant activities in platelet suspensions lysed by sonication correlated directly with the degree of lysis (loss of LDH and 51Cr). Separate measurements of platelet factor 3 (PF3) and Factor V/Va activity revealed significant differences in appearance of these platelet activities in sonicated cell suspensions. Platelet factor 3 activity increased almost in parallel to the loss of 51Cr, whereas Factor V/Va activity became available at a significant slower rate. This might be explained by the localization of Factor V/Va activities inside the alpha-granules and therefore not immediately available on the surface of the partially lysed platelets. No increase in lactate dehydrogenase or 51Cr-loss was observed during 12 min incubation of platelet suspension with collagen or thrombin, whereas both PF3 and Factor V/Va activities increased. Thus, the high platelet factor 3 activity of 34% (lysed platelets 100%) measured in thrombin stimulated platelet suspensions probably represents "lysis-independent" activity.
mesh_terms: D001779:Blood Coagulation Factors / Q000032:analysis*; D001792:Blood Platelets / Q000187:drug effects; D002857:Chromium / Q000378:metabolism; D003094:Collagen / Q000494:pharmacology*; D005165:Factor V / Q000032:analysis*; D015943:Factor Va; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects*; D010977:Platelet Factor 3 / Q000032:analysis*; D013917:Thrombin / Q000494:pharmacology*
chemical_list: D001779:Blood Coagulation Factors; D002857:Chromium; D010977:Platelet Factor 3; D015943:Factor Va; D005165:Factor V; D003094:Collagen; D007770:L-Lactate Dehydrogenase; D013917:Thrombin