Fig. 4. Fate of single cardiomyocytes. One cell per grid square was labelled with the red fluorescent tracker dye, PKH-26 (see Materials and Methods), and cultured for 24 days prior to fixation and analysis. There were a total of 238 initial cells from three independent experiments. (A,B) Confocal micrographs of squares where two daughter cells (A) or a binucleate cell (B) were observed. Staining for MyHC is in green and DNA (Hoechst 33258) in blue. Scale bar: 50 µm.