Cardiomyocytes differentiated from the iPS cells. A: Several cardiac markers were discovered using RT-PCR indicating their expression at mRNA level. Data from UTA.04602.WT is shown here. B: By immunocytochemical staining it was shown that the iPS cell-derived cardiac cells express proteins specific for cardiomyocytes. Cardiac troponin T, α-actinin, myosin heavy chain (MHC) and atrial myosin light chain 2 (MLC2a) were detected from the cells. The pictures on the left side are from the line UTA.04602.WT and the pictures on the right side are from UTA.04607.WT. In the pictures showing MHC and MLC2a with green fluorescent, red indicates troponin T and in all pictures DAPI staining of nuclei is seen in blue. C &D: A micro electrode array (MEA) was used to define the electrical properties of the iPS cell-derived cardiomyocytes. The beating rates (BR) and field potential durations (FPD) of cell aggregates were evaluated (B: UTA.04602.WT, BR = 58, FPD = 283 ms and C: UTA.04607.WT, BR = 66, FPD = 391 ms).