[Reparative processes during embryonal and postembryonal myocardiogenesis in Gallus domesticus L]. / O reparativnykh protsessakh v émbrional'nom i postémbrional'nom miokardiogeneze Gallus domesticus L.

By means of light and electron microscopy methods during embryonal and postembryonal periods in birds (Gallus domesticus L.) myocardial reparative processes have been studied after its lesions produced with electrothermocoagulation. Primary closing of the wound in the cardiac wall of 3- and 5-day-old chick embryos is connected with certain reactive changes in epicardium and endocardium. In 7-10 days the cardiac wall completely restores its integrity by an intensive growth and development of intact cardiac areas. A weak development of the myocardial connective tissue stroma contributes to it. Reparative processes in the cardiac wall of 18-day-old chick embryos and in newly hatched chickens proceed with an active participation of the connective tissue, which subsequently forms a scar at the place of the lesion. Isolated redifferentiating cardiomyocytes surrounded with the connective tissue are subjected to atrophy on the 45th-60th day.

[The recovery process in the fetal rabbit myocardium following mechanical trauma]. / Vosstanovitel'nye protsessy v miokarde plodov krolika posle mekhanicheskoi travmy

Healing processes of the myocardium after an injury during the intrauterine period were studied. After the mechanical trauma of the heart the rabbit fetus is kept in the maternal organism and is born in due course. It was found that the healing of the injured part of the cardiac muscle occurred shortly and was due to the high proliferative activity of the cells. Morphological structure of the tissue appearing at the site of injury is very similar to that of the muscle tissue. However, further studies are necessary for final decision.