Polyploidization was induced by nocodazole and TPA in UT-7 cells. Human megakaryocytic leukemia cell line UT-7 was seeded at 5 × 10⁵ cells/mL and cultured in the absence or presence of either (•) nocodazole (50 ng/mL) or (▴) TPA (10 ng/mL) for 3 days. (A) The cells were harvested at given time points, and the proportion of hyperploid cells (cells containing more than 2 nuclei) was determined by morphologic examination on the cytospin specimens. The mean ± SD (bar) of seven independent experiments is shown. (B) Wright-Giemsa staining of each specimen is shown. (Original magnification × 400).