[Ultrahistochemistry of cardiomyocytes in acquired mitral lesions of the heart].

A study of myocardium of patients with mitral stenosis was performed using ultrahistochemical methods at different stages of disease and in the course of valve replacement operation. A quantitative analysis of degenerative changes was introduced, the results of which correlated with the severity of heart failure. A pronounced heterogeneity in mitochondrial enzyme activity has been detected cytochemically. In some apparently "unaffected" cardiomyocytes an active alterative process was expressed in an increase of sarcolemma permeability for electron-microscopic tracers. An elevated fenestration of membrane barriers was noted at the stages of anoxic heart arrest. Using tannic acid it was possible to demonstrate a penetration of plasma protein-polysaccharide complexes into cell sarcoplasma. There were observed topographic variations in the distribution of acid phosphatase activity.