Transmission electron microscopic images of blood-derived iPS cells. (a) Representative high-resolution electron micrographs of primary human fibroblasts (HCF fibroblast), HCF-derived (HCF1 iPS), and HPC-derived (HPC-A1) iPSCs are shown. Mitochondria (MT) and nucleus (N) structures are denoted in the micrographs. (b) Frequent mitotic events were observed in the blood-derived iPSCs. Mother and daughter centrioles are represented by the arrowhead and arrow symbols, respectively. Scale bars are represented in micrometers.