Fig. 6. Increase of ES-cell-derived- and neonatal cardiac cell numbers following treatment with 100 nM H₂O₂. Cardiac cells were treated with H₂O₂ for 24 hours. Subsequently, cell numbers were analyzed following immunohistochemical staining for sarcomeric -actinin and Sytox Green counterstaining cell nuclei by microscopical inspection. The images in panel A show representative ES-cell-derived cardiomyocytes (a,b) and neonatal cardiomyocytes (c,d), which remained either untreated (a,c) or were treated with H₂O₂ (b,d). Bar, 20 µm. (B) Mean ± s.e.m. of 11 experiments. ^*P<0.05, significantly different to the untreated control.