Summary
Platelets have been separated from plasma of a series of normal volunteers by three
methods: albumin density-gradient centrifugation, gel filtration, and a combination
of the two. The efficacy of these three methods has been assessed by determination
of the percentage recovery of the platelets, their aggregability by ADP, collagen
and thrombin, platelet factor-3 availability, content and release of platelet adenine
nucleotides and electron microscopic appearances. Platelets prepared by all three
methods showed some loss of sensitivity to aggregating agents, minor activation of
platelet factor 3 and morphological changes, as compared with platelets in PRP. Function
and morphology were best preserved in platelets prepared by the combined method and
most disturbed in those prepared by repeated washing on an albnmin density gradient.
