Blood film and ultrastructure abnormalities of Nbeal2^−/− mouse platelets. Blood films were prepared from WT (A), Nbeal2^+/− (B), and Nbeal2^−/− (C) mice and stained with Wright-Giemsa stain prior to light microscopy. WT (A) and Nbeal2^+/− (B) blood films show typical platelet (black arrowheads) size and morphology with discernible granulation against light cytoplasmic staining, and the Nbeal2^−/− film (C) shows gray-appearing platelets with indistinct granulation and visible vacuoles. Thin-section transmission electron micrographs of representative platelets are from WT mice (D) and Nbeal2^−/− mice (E). Multiple α-granules (white arrowheads) were evident in WT platelets and absent in Nbeal2^−/− platelets, which are larger on average. Magnification ×40 000; scale bars represent 500 nm.