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In order to analyse the mechanism of the positive inotropic effect on the myocardium of cardiac glycosides, the author studied on the timed localization and distribution in the rat myocardial cells of the glycosides by means of electron microscopic autoradiography.Since most part of the glycosides may be lost from the tissues during the process of fixation and dehydration, the methods were studied. The radioactivity in the tissue was measured by the oxygen combustion method. Little part of the glycosides was lost when the tissues were fixed with glutaraldehyde and osmium tetraoxide, and then dehydrated with acetone series.By this method the author found most silver grains distributed in the transverse system (T system), the sarcoplasmic reticulum and the sarcolemma. This may suggest that the glycosides act upon the membraneous component.

On 79 ECG tracings obtained from 31 uremic patients, the influence of serum Ca, Na, and K concentrations on the QT duration in ECG was analyzed by multiple regression technique. It was found that Ca and K had negative and Na had a positive effect on QT duration, although only the effect of Ca was reaching the statistically significant level. Since serum electrolytes had correlations with each other, they were orthogonalized and tested for significance once again. Still Na and K did not reveal significant influences by this procedure. However, the effects of Na and K on QT duration were as the same direction and magnitude as reported in older literatures.In the course of orthogonalization it was found that Ca and Na had negative influences on K. It seems that this fact presents a sound basis for the therapeutic use of Ca and Na salts in hyperpotassemia.