(a) Platelets treated for the cytochemical detection of dense granules by the uranaffin technique of Richards and Da Prada10 and then immunolabeled for Gp Ib (polyclonal anti-Gp Ib/GAR 10 nm). The gold label lines the plasma membrane (pm) and is occasionally found on α-granules (A). Moreover, a granule with a dense content (D) is also labeled for Gp Ib. (Original magnification × 40,000.) (Inset) High magnification of a dense granule displaying immunolabeling for Gp Ib. (Original magnification × 59,000.) (b) Platelets pretreated by the uranaffin technique of Richards and Da Prada,10 embedded in GMA, and then immunolabeled for Gp IIb-IIIa (polyclonal anti–Gp IIb-IIIa/GAR 10 nm). Gold label is evident along the plasma membrane (pm) as well as along the α-granules (A). Note that the limiting membrane of the two dense granules (D) is also strongly labeled. (Original magnification × 32,000.) (Insets) High magnification of dense granules labeled for Gp IIb-IIIa. (Original magnification × 59,000 and × 92,000.)