Comparison of certain functions of human platelets separated from blood by various means.

Human platelets separated from blood by six different methods have been compared for aggregability, adhesion to glass, adenine nucleotide content and release, and adenosine triphosphatase and cholinesterase activities. Methods of separation of platelets from blood included three differential centrifugation technics, gel filtration and two albumin density gradient methods. Platelets prepared by the different methods aggregated comparably except those separated by albumin density gradient technics which tended to be hyporeactive. Differences in adhesion to glass, adenine nucleotide content and release, and monitored enzyme activities of the various platelet preparations were noted in several cases but were not marked in general. Ultrastructural studies, reported elsewhere, revealed that platelets separated by the method of Mustard or by gel filtration were less altered morphologically than those separated by the other methods. Platelets separated from blood by gel filtration also appeared somewhat superior functionally to platelets separated by other methods.