Function and morphology of 111-In-labelled platelets. In vitro, in vivo and ex vivo studies.

111In-labelled human platelets were aggregated with ADP and subjected to ultrastructural morphometric analysis. In addition, the hemostatic function in vivo and the ultrastructural morphology ex vivo of rabbit platelets were examined. The platelet isolation and labelling procedures exerted no certain influence on the aggregation response, and platelet surface/volume calculations did not indicate that platelet activation had taken place. Bleeding time experiments in rabbits indicated that the hemostatic effectiveness of the labelled platelets was unimpaired. Transfused 111In-labelled platelets isolated from the recipient rabbits exhibited fewer electromicroscopic signs of platelet activation than the same platelets prior to transfusion. Our results indicate that the described procedure for isolation and 111In-labelling of platelets induces only insignificant damage to the platelets.