Ultrastructure of platelets.

(A) In GPS, normal α-granules are absent from the platelets and replaced by vacuolar structures (v) the size of normal α-granules. (B) Platelets of large size displaying membrane complex (mc) and devoid of normal α-granules are encountered. (C) Platelets from a normal subject are smaller and display conspicuous α-granules (A). (Panels A-C, original magnification × 10 500.)