[DNA biosynthesis in the muscular and connective tissue cells of the heart in experimental myocardial infarct].

In 60 rabbits with experimental myocardial infarction induces by ligation of the anterior branch of the left coronary artery, DNA synthesis was studied by means of H3-thymidine in muscular and connective tissue cells depending on the period of myocardial infarction. The development of myocardial infarction in the cardiac muscle was stated to be accompanied by activation of DNA synthesis in the connective tissue cells not only in the necrotic zone but in the adjacent, as well as in distant areas of the myocardium and in stromal cells of the auriculum. Indices of H3-thymidine labeled nuclei were of high value during the acute period of myocardial infarction and gradually decreased with the time elapsed since the operation. During the period of the myocardical infarction organization high activity in DNA synthesis was revealed in connective tissue elements of the epicardium and the subepicardial zone of the heart. Myocardial cells of the cardiac auriculi incorporated H3-thymidine but extremely seldom-single labels per thousands of nuclei. In the auriculi with application of prolonged sessions of the labeled precussor introduction, DNA synthesising nuclei were revealed, sometimes with paired nuclei of cardiomyocytes.