[Ultrastructural changes of myocardial biopsy from six children with latent Keshan disease]

Myocardial biopsy from six children with latent Keshan disease was performed. Samples taken from right heart ventricles were prepared and investigated under an H-600 electron microscope. Some samples were also prepared with the lanthanum preparation for studying the membrane permeability of the myocardium. Ultrastructurally, most of the sarcolemma of myocardial cells remained intact, and some occasionally showed local minimal defects. Lanthanum particles are located outside the myocardial cells, and only a small number of them entered into the cells; but they were located between myofibrils and mitochondria. Mitochondria showed some extent of proliferative and degenerative changes. Some of them were swollen, and their cristae resolved and matrix lightly stained. Transverse system, sarcoplasmic reticulum and the perinuclear cisterns were dilated apparently. Myolytic foci could be seen scarcely. Proliferation of collagen fibers could also be found here and there in all the samples. It was showed that certain permeability disorders of the sarcolemma were still existent, although these patients were in a period of compensation and reparation. Perhaps, some pathogenic factors were still acting on them at that time.