Figure 1. Eight-day in vitro (DIV) growth of myocardial cells obtained from newborn rat heart. (A) Changes in the proportion of dividing cells (c-mitoses) over 8 d of culturing. (B) Changes in mean cell volume over 8 d of culturing. Values are expressed as the mean ± SD (C) Temporal changes in the number of cultured myocardial cells with different cell volume. (a) Population of small cells with mean cell volume <250 μm³; (b) Population of cells with mean cell volume of 250–1000 μm³; (c) Population of cells with mean cell volume >1000 μm³. (D–F) Polyploid and multinucleated cardiac myocytes. Hematoxylin staining. Digital camera Leica DFC300 FX, Trinocular Microscope H 605T (WPI), objective ×40. (D) Polyploid cardiac myocyte, DIV 8. (E) Cardiac myocyte with 5 nuclei, DIV 4. (F) Binucleated cardiac myocytes, DIV 6.