Abstract
Summary
Little platelet acid phosphatase or platelet factor 4 was made available from thrombasthenic platelets by adrenaline or ADP. Conversely, collagen induced marked but subnormal availability of platelet acid phosphatase and normal availability of platelet factor 4. Normal or increased amounts of ADP were released from thrombasthenic platelets in plasma by thrombin and by kaolin. It was concluded that the absence of release by ADP and epinephrine was the direct consequence of the lack of formation of large aggregates.
An hypothesis is suggested to explain the abnormalities found in thrombasthenia which is a defective thrombosthenin responsible for abnormal fibrinogen-thrombosthenin affinity, involved in platelet aggregation and clot retraction.
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