Scanning electron micrographs of wild-type and β3-null mouse platelets adherent to collagen demonstrate platelet morphologic features similar to those of human platelets without and with treatment with 7E3, respectively.

Wild-type and β3-null mouse blood was collected into ACD, and the resultant PRP/PRB mixtures were added to collagen-coated microtiter wells for 1 hour. Samples were then prepared for scanning electron microscopy. High-power (A) and low-power (B) views of wild-type platelets, and high-power (C) and low-power (D) views of β3-null platelet adhesion. Wild-type platelets in panel A show that the platelets have spread in a sheetlike formation; a few remaining follower platelets, with their granulomeres intact, are seen on top of the spread platelets. The extensive “island” formation is apparent at lower power (B). (C) The β3-null platelets do not spread as a sheet, though they appear to spread individually more than human platelets in the presence of 7E3. Note also Figure 3C.