It seems very probable that of beta-adrenergic receptor blocking agents currently used, 4-(2-hydroxy-isopropylamino-propoxy)-indole (LB-46) has the most potent beta-adrenergic blocking activity. The present investigation aimed at illuminating the protective effect of LB-46 on desacetyl-lanatoside C (deslanoside)-induced toxicity to the heart of guinea pigs by means of the analysis of dose-response curves in comparison with propranolol. As the result both beta-adrenergic receptor antagonists showed a considerable suppressive activity against deslanoside-induced cardiotoxicity at the serial infusion rate of deslanoside. Thus there was no apparent difference between the potency of the antagonistic activity of both drugs against cardiotoxicity and that of their beta-adrenergic activity. Consequently it was impossible to con-firm the possibility of correlation between an antagonistic potency against cardiotoxicity and a beta-adrenergic receptor blocking potency of both drugs. These results may suggest that the mechanism of the suppressive activity of LB-46 against deslanoside-induced cardiotoxicity is unrelated to the adrenergic influence.

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To determine the graded cardiopulmonary effects and fate of pulmonary gas embolism, 11 sheep (with chronically implanted Doppler ultrasonic flow probes on pulmonary and brachiocephalic arteries) were subjected to experimental intravenous injection of nitrogen, oxygen and carbon dioxide. Three different rates of injection of each gas (0.03, 0.09 and 0.15ml/kg/min) were used for 30 minutes. Doppler ultrasonic flow probes were found to be very sensitive to the injected intravascular gas and produced characteristic "chirps." The electromagnetic blood flowmeter was insensitive to the passage of these gases. Cardiopulmonary responses include elevation of pulmonary arterial pressure, diminished cardiac output and arterial hypoxemia. Nitrogen produced the greatest response and carbon dioxide the least, correlating with differences in solubility and diffusion rates. These responses developed with a one-half time of 15-20 minutes, with recovery, following cessation of injection, at the same rate. No statistically significant changes occurred in heart rate, systemic arterial pressure, pH or Pco₂. Passage of intravenous gas through the pulmonary vasculature to the systemic circulation occurred only at the 0.15ml/kg/min dosage hate. The opening of the intrapulmonary arteriovenous shunts was primarily responsible for the decrease in arterial oxygen tension and passage of gas through the lung.

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The changes in the Q-II_A interval were analysed using direct-writing phonocardiograph and Master's double two-step test for the purpose of early detection of the left ventricular dysfunction in cases of systemic hypertension, arteriosclerosis and ischemic and/or hypertensive heart disease. A linear relationship between the Q-II_A interval and the square root of the R-R interval was demonstrated by statistical analysis in 101 normal subjects aged ranging from 18 to 66. Using this relationship, the Q-II_A interval was corrected by cycle length and Q-II_C index was obtained. The changes in Q-II_C index before and after exercise were studied. A significant prolongation of Q-II_C index before exercise and a failure to decrease in Q-II_C index I minute after exercise was demonstrated in the diseased groups. From the result of this study, the phonocardiographic analysis of the Q-II_A interval before and after exercise is considered as a useful diagnostic procedure for evaluation of the left ventricular dysfunction.

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Influence of ascorbic acid deficiency on serum and hepatic lipid and on the aorta were studied. Two groups of ascorbic acid deficient guinea pigs were made by feeding with scorbutic diet with or without 5% coconut oil for two weeks (group 3 and 1). Control animals of the experimental groups were fed with the same diet of previous two groups and received 25 mg of ascorbic acid subcutaneously for the same period (group 2 and 4). Moderate increase of triglyceride and cholesterol ester and beta-lipoprotein in the serum of ascorbic acid deficiency (group 1), and markedly to approximately twice of normal in the ascorbic acid deficiency with coconut oil feeding (group 3). Increase of serum lipids and depression of plasma lipoprotein lipase activity by ascorbic acid deficiency was prevented by ascorbic acid administration as observed in the control groups. Histological examination of the aorta revealed edematous swelling of the ground substance in the intima and media in the scorbutic, and early atheromatous lesions of accumulated foam cells in the intima of the ascorbic acid deficiency with coconut oil feeding. These findings suggest that any factors disturbing ascorbic acid metabolism induce an increase of serum lipids and altered vascular wall metabolism, and consequently follows atherosclerosis.

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Comparisons have been made on the vectorcardiogram, electrocardiogram and cardiac size of chest X-ray photograph between the healthy group and the patient groups with mitral stenosis and pulmonary emphysema, demonstrating the apparent difference of the effects of the right heart load. The possibility was suggested of making diagnosis and prescience of prognosis in chronic pulmonary emphysema based on the grade of right heart load. By analysis made on vectorcardiogram of 120 cases with chronic pulmonary emphysema, QRS loop was classified into three types in the horizontal plane and four types in the frontal plane. It is proved that the classification of QRS loop is useful for diagnosis and prognosis in the chronic pulmonary emphysema.

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Three kinds of kidney extract namely, adrenalectomized, sodium restricted and normal rat-kidney extract were prepared. Hypertension-inducing potency as well as renin activity in each extract was determined and discrepancy between the two activities was found. This experiment suggests the occurrence of at least one pressor substance apart from renin in the kidney which effects blood pressure elevation after a latent period. A "dual renal pressor substance" hypothesis is proposed concerning the humoral mechanism of renal hypertension.

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The ballistocardiograms (BCGs) of the cases with auricular fibrillation are generally complicated in their waves. Therefore, it is not easy to analyse the BCGs of such patients by routine method. Harmonic analysis was applied in order to interprete such BCG accurately. The examines consisted of 15 cases of auricular fibrillation with mitral valvular disease and 30 cases of auricular fibrillation with hypertensive heart diseases and 10 healthy persons, totaling 55 cases. The longitudinal BCGs were recorded during rest breathing for one minute on a magnetic tape by using von Wittern-type sublow-frequency table and a Sony data recorder (PWA-23, MA-33). The recorded magnetic tape was rerecorded on a magnetic tape of a Sony correlater (CCA-32 type). Autocorrelograms of BCGs were obtained by setting the correlater with the rerecorded magnetic tape. All the autocorrelograms of the patients of auricular fibrillation showed damping patterns, and they were classified into three types. Type 1 consists mainly of aperiodic component with a little random component. Type 2 consists of aperiodic component and of random component. Type 3 consists only of random component. Among the autocorrelograms of BCGs of 45 cases with auricular fibrillation, 29 cases (44%) belonged to Type 1, 15 cases (33%) to Type 2, and 10 cases (22%) to type 3. The power density spectra of BCGs were obtained by the Fourier transformation of the autocorrelation function. The power density spectrum of BCG in the auricular fibrillation. either with mitral valvular diseases or with hypertensive heart diseases, damped slowly, and then converged on the zero line about 10 cps. But it showed an abnormal fluctuation over the frequency zone from 3 cps to 6 cps in all the cases of the auricular fibrillation with mitral valvular diseases. The curves of the power density spectra of BCGs showed sinusoidal wave patterns of small amplitude in all the cases of auricular fibrillation with hypertensive heart diseases. This pattern differed distinctly from that of auricular fibrillation with mitral valvular diseases. In healthy persons, the curves of the power density spectra of BCGs showed regular and damping sinusoidal wave patterns.

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