Comparison of megakaryocytes between early YS and adult BM.

(A) Photomicrographs show megakaryocytes stained with AchE in 8.5-dpc YS (upper) and adult BM (lower) (original magnification × 1000). (B) Comparison of size of megakaryocytes in 8.5-dpc YS and adult BM. The horizontal bars in each group represent the mean perpendicular diameters of megakaryocytes. The numbers of measured megakaryocytes are presented in parentheses. The megakaryocytes in 8.5-dpc YS were significantly smaller than those in adult BM (P < .001).