[Myocardial regeneration in chick embryos after cyclophosphane exposure]

By means of light and electron microscopy, radioautography, regeneration of the chick embryo myocardium has been studied at metabolic lesions produced with cyclophosphamide injection into the egg air chamber on the 4th day of incubation. Certain destructive processes in cardiomyoblasts, increased cellular death, decreased activity of DNA synthesis and mitotic activity of the cardiac muscular cells are noted. Two-four days after cyclophosphamide injection, ultrastructure of the cardiomyoblasts is restorted, as well as their DNA synthesis is normalized. The mitotic activity is higher than the control one. Restorative processes in the chick embryo myocardium take place at the expense of the intracellular regeneration occurring together with the mitotic division of the cardiac muscular cells.