Cell morphology in serum-containing culture medium.

Cells were cultured for 3 days. (A) Undifferentiated cells cultured in 20% FBS-containing medium. Original magnification × 200. (B) PMA-induced full differentiation in serum-containing medium, showing adherence, size increase, polyploidization, and proplatelet formation. In situ Giemsa staining. Original magnification × 200. (C) Electron micrograph showing a differentiated cell with an elongated cytoplasmic process. Original magnification × 3000. (D) Ploidy of undifferentiated cells. (E) Ploidy of differentiated cells. Nonadherent cells and adherent cells (dislodged by means of 0.05% trypsin-EDTA) were collected by centrifugation. Cells were stained with 7-AAD as indicated in “Materials and methods” and analyzed by flow cytometry. Representative of 5 independent experiments.