Dynamics of plasma renin activity (PRA) in peripheral and renal vein was studied in 22 patients with various types of renovascular hypertension. Significant elevation of resting peripheral vein PRA (PPRA) was observed in 7 out of 8 cases with unilateral main renal artery stenosis (type I). However, PPRA remained normal or slightly elevated in 5 cases with unilateral branch renal artery stenosis (type II), in 5 out of 6 cases with bilateral main renal artery stenosis (type III), and in one with unilateral main renal artery stenosis of the remaining kidney after contralateral nephrectomy. In all cases with type I and II higher renal vein PRA (RPRA) was found on the affected side, while RPRA in type III remained in normal range or slightly elevated on both sides. The ratio of RPRA between higher and lower sides was 1.27±0.10 (SE) in type III. These values were smaller than that of 2.02±0.24 (SE) in type I and II, and were not significantly different from that of 1.20±0.04 (SE) in control group. In statistical analysis of 79 cases including 57 cases reported by other authors, normal PPRA level was found in 69.1% of patients with type III stenosis, while PPRA was normal in only 19.5% Of cases with type I stenosis, and in 50.0% of cases with type II. There was significant difference in frequencies of normal PPRA between type I and III (P<0.001), and also between type I and II (P<0.05), respectively. Dynamics of PRA in renovascular hypertension was in close association with the types of renal arterial abnormality. Patients with renovascular hypertension, irrespective of their resting PPRA, responded to i.v. injection of furosemide and upright position with remarkable increase in renin secretion. This procedure was practically useful for the differential diagnosis of renovascular hypertension.

View full abstract

The mechanism of the bigeminal rhythm induced by the toxic dose of rapid acting unique cardiac glycoside; Proscillaridin A, was investigated by means of the intracellular microelectrode technique, upon the guinea pig ventricular fibers, and the clinical case record of bigeminal rhythm induced by its intoxication was also analysed. On the experimental finding, the bigeminal rhythm appeared when the repolarization phase 2 was decreased about 40%. Clinically, the plethysmographic finding may be the good parameter to judge the appropriate dosage of Proscillaridin A for its maintenance dose for every individual patient.

View full abstract

We previously reported that the occlusive thrombosis located in the hepatic vein, left atrium, and mesenteric artery was observed in the spontaneously hypertensive rats at advanced age. In this experiment, the blood clotting, platelet aggregation, and morphological and biochemical examinations of blood in the male and female hypertensive rats were performed in order to elucidate the mechanism of thrombus formation.

View full abstract

Pulmonary diffusing capacity (D_LCO), alveolar membrane diffusing capacity (D_MCO), and pulmonary capillary blood volume (V_C) were determined with CO single breath method in (i) healthy subjects and, (ii) patients with cardiopulmonary diseases. In the latter right heart catheterization was also performed. Values obtained were compared between healthy subjects and patients with cardiopulmonary diseases. They were also compared with those reported by other workers. Relationships between D_LCO, D_MCO or V_C and hemodynamic parameters of pulmonary circulation were examined.

View full abstract

In healthy subjects and in patients with cardio-pulmonary diseases, pulmonary capillary blood flow (Qc) was measured by acetylene method and pulmonary capillary blood volume (Vc) was measured by CO single breath method. From these, pulmonary capillary mean transit time (t_c) was calculated. Relationships between tc and various hemodynamic parameters of pulmonary circulation in cardio-pulmonary diseases were examined. Further, effects of exercise on Vc, Qc and tc were examined.

View full abstract

A rare case of the coronary artery fistula was described. The retrograde aortogram revealed a huge and tortuous right coronary artery drained into the left ventricle. A phonocardiographic recording revealed a systolic murmur with short duration and a louder diastolic murmur with crescendo-decrescendo configuration.

View full abstract

During the period varying from seven days to four years after surgery, phonocardiograms, carotid pulse tracings and apexcardiograms were recorded on the fifty patients who underwent cardiac valve replacement with Wada-Cutter valve. They consist of twenty- four aortic valve replacements, twenty-one mitral valve replacements. three tricuspid valve replacements and three triple (aortic, mitral, tricuspid) valve replacements. Measurements described below were made on those recordings and they were compared both with normal valves and with those obtained from valve replacements using other than Wada-Cutter valve and following conclusions were drawn. Aortic Valve Replacement: 1. By means of stethoscope, on opening clicks were heard but characteristic systolic murmur and closing clicks of the prosthesis were well audible. However those clicks were more faint than those of caged ball valve and they were considered to be mentally less annoying the patient. 2. On the phonocardiogram, diamond-shaped systolic murmur, of ejection type, was recorded following the opening click of prosthesis. However this dose not mean a presence of stenosis created by the prosthesis but was considered to be brought about rather by the turbulance produced by Wada-Cutter valve. 3. Q-M_I interval, mean 0.084 seconds, appeared to have little more prolonged than normal and the hypothesis, that the presence of rigid metal ring of prosthesis hampers closing motion of the mitral valve, was considered to be the cause of that prolongation. 4. M_I-OC interval, mean 0.044 seconds, was considered to be within normal range but it was assessed to be little shorter than those of ball valve was deduced to open more easily than the other type of prosthesis. 5. OC-CC interval, left ventricular ejection time, mean 0.326 seconds, was measured to be little longer than normal. The prolongation was partly attributed to the trivial stenosis caused by prosthesis but another major etiology was considered to be present because the mean pressure gradient has been found to be approximately 5 mmHg in the series of pressure monitorings. 6. The results of analysis of carotid pulse tracing graded Wada-Cutter valve to be within normal range or little excess in the degree of stenotic effect and it well corresponded with the results of pressure monitoring.

View full abstract

Part I Myofibril The development of the human embryo heart, especially the mode of development of myofibrils were studied by means of the electron microscope, and the following results were obtained. The myofilaments were found already in the cytoplasma of the CR length 20 mm myocytes. There was the finding that the myofilaments might be produced from the polysomes. Initially the myofilaments were distributed at random in the cytoplasma, and then were gathered and formed into bundles (myofibrils). The myofibrils three-dimentionally the network structure. Those myofibrils seemed like to lined up gradually into certain direction as the myocyte matured, and showed the striation as following order; the Z-line, A band and H disc. In cross section, the myofilaments showed hexagonal alignments, and these figures were the same of those of adult. In the case of the 3 month human fetal cardiac myocytes, the basic structure of myofibrils were established in part, and assumed to able to contract. In the case of the 7 month human fetal cardiac myocytes, the almost all of cytoplasm were occupied with the myofibrils which seemed like that of adult heart, These findings might be correlated with the fact that the immatured baby at this stage in able to survive under the careful treatment. Part II Mitochondria and Glycogen The developmental changes of the human embryo heart, in special reference of the mitochondria and glycogen were studied by means of the electron microscope, and the following results were obtained. A few mitochondria were distributed in the cytoplasm of the CR 20 mm embryo myocytes, and the cristae mitochondriales were developed poorly in this stage. In the case of the CR 25 mm length fetus myocytes, the number of mitochondria increased and the cristae mitochondriales developed more. Since some mitochondria distributed close to the myofibrils, it might be thought that the cardiac muscle would be already able to contract in this stage. As the embryo matured, the distribution of glycogen in the cytoplasm decreased. The particle of glycogen was the β-type. In the point of view of the developmental process of mitochondria, myofibril and glycogen, it might be considered that the ultrastructure of these organella would be accomplished partially in the cytoplasm of the CR 25 mm length myocytes.

View full abstract

Among the antiarrhythmic agents in current use, quinidine, procainamide and related compounds are capable of causing a shift, to the right, to the S-shaped curve (Weidmann curve) that related maximum rate of rise (MMR), or overshoot, of the cardiac muscle action potential to the resting potential (RP). This effect, so-called "membrane stabilizing effect", is considered to be chiefly responsible for the antiarrhythmic actions intrinsic to these agents. On the other hand, lidocaine, another antiarrhythmic agent, is said to differ considerably in its electrophysiological properties from "quinidine-like" substances; lidocaine was found to increase the duration of the absolute refractory period relative to the total duration of the action potential. Evidences are accumulating recently in favor of a concept that the upstroke of the cardiac muscle action potential is composed of two distinct components, i.e., rapid initial rising phase and slow rising phase. The rapid rising phase is probably due to a rapid inflow of sodium ions into the cell and the end-point of the rapid rising phase has been termed the spike potential. Slow rising phase is probably due partly to slow inflow of calcium ions and partly to the decaying portion of the once very fast inflow of sodium ions. It is also becoming more and more evident that the slow inward flow of calcium ions is an important constituent of the plateau phase of the ventricular muscle action potential. In view of these new knowledges, what has been termed overshoot in the past may mean either the spike potential or the peak of the plateau potential. Therefore. there is an need of re-evaluating the past studies where antiarrhythmic agents and other compounds were examined for their effects on overshoot, among other things. In the present study, the influence of a series of antiarrhythmic agents, propranolol, quinidine and lidocaine, were examined for their effects on action potentials of dog's ventricular muscle fibers, with special emphasis on the spike and plateau potentials and for the formation of plateau phase, studies were made also of the "spike-plateau-relationship", plotting plateau potential in ordinate and spike potential in abscissa with and without these antiarrhythmic agents. Description of these new factual informations is the purpose of this paper.

View full abstract