Tissue respiration and rate of incorporation of P³² into ATP of rat aorta were studied by using Warburg technique in vitro. 1. A decrease of the incorporation rate of P³² into ATP was observed within 45 minutes after sacrifice when the aortas were stored in a cold Krebs-Ringer-phosphate solution (pH 7 .4), 2. The metabolic inhibitors, cyanide and fluoride, depressed both the respiration and the incorporation of P³² into ATP. 3. The incorporation rate of P³² into ATP of aortas from 12 to 15 months old rats was lower than that of 1 to 2 months old rats, while no significant difference in Qo₂ of aortas from young and old rats was observed. 4. The enhancement of both the respiration and the incorporation of P³² into ATP of rat aorta by acetylcholine was significant in young but not in old rats. 5. The incorporation of P³² into ATP was depressed in aortas from rats fed a magnesium deficient diet for 2 to 4 weeks, while the oxygen uptake was not decreased in a significant amount.

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1. The contents of norepinephrine, epinephrine, dopamine, and dopa were determined in various portions of the heart in 6 intact dogs. Catecholamines were separated with aluminum hydroxide and cation exchange resin using Duolite C-25. Norepinephrine, epinephrine, and dopa were determined fluorimetrically by the modified method of EULER and FOLDlNG and dopamine was by the method of WEIL-MALHERBE and BONE. 2. Although epinephrine, dopamine, and dopa were distributed almost equally throughout the heart, the norepinephrine concentration was significantly higher in the atria than in the ventricles.

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1. The contents of norepinephrine, epinephrine, dopamine, and dopa of the heart were determined fluorimetrically in 24 dogs from 1 to 50 days following bilateral cervical sympathectomy. The results were compared with those obtained from intact dogs in the previous studies. 2. After bilateral cervical sympathectomy, the norepinephrine content show a rapid decrease from 4 days to 7 days and a slow decrease within the following 14 days. No tendency of recovery was apparent in the heart for 50 days following the operation, the norepinephrine content remaining almost at an equal level. The same operative procedure, however, had no significant effect on the concentrations of dopamine and dopa 3. It was postulated that norepinephrine could not be synthesized and/or accumulated in the heart following bilateral cervical sympathectomy, but that cardiac muscle might synthesize dopamine for itself.

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1. The norepinephrine concentration was determined fluorimetrically in various portions of the heart of 30 unilaterally sympathectomized dogs. The operation was performed on the left side in one half of the dogs and on the right side in the other half. 2. The norepinephrine concentration showed a significantly marked decrease in both atria, the right ventricle, the ventricular septum, and the anterior portion of the left ventricle following unilateral cervical sympathectomy on either side. It exhibited also a marked decrease in the postero-lateral portion of the left ventricle following left cervical sympathectomy. It was not affected, however, in the same portion of the left ventricle by right cervical sympathectomy. 3. From the results above mentioned it was postulated that the postero-lateral portion of the left ventricle might be supplied exclusively by the left cardiac sympathetic nerve and that the other portions of the heart might be innervated bilaterally with some unilateral preponderance. The right ventricle was assumed to be supplied predominantly by the right cervical, sympathetic nerve, while the anterior portion of the left ventricle and the ventricular septum were considered to be innervated predominantly by the left nerve. 4. It seems that the cardiac sympathetic nerve of the intact side may compensate the function of the corresponding nerve of the other side where unilateral cervical sympathectomy has been performed. This presumption has been made, since the norepinephrine concentration showed a slight tendency toward the preoperative level 28-30 days following unilateral cardiac sympathectomy.

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It has been reported that the pulmonary artery pressure decreased in acute induced was hyperoxia. The purpose of this study is to observe the changes of pulmonary hemodynamics and respiratory functions in acute induced hyperoxia and to clarify whether the pulmonary hypertension should be released by oxygen inhalation in patients with pulmonary impairment, or not. Materials and Methods In 9 normal subjects, 30 patients with chronic pulmonary disease (emphysema 15, fibrosis 4 bronchial asthma 4 and others 7) and 11 patients with chronic cardiac disease (mitral valvular disease 8 and aortic valvular disease 3), right heart catheterization was performed, and pulmonary hemodynamics and respiratory functions were studied before and during inhalation of 40% and then 100% oxygen. Results I Changes of respiratory functions 1) Ventilation Although there was no significant change in respiration rate and minute ventilation during others. the inhalation of high oxygen either in three groups, emphysema patients showed a tendency eases showed a slight decrease within a range of of slight decrease in respiration rate and the other groups showed that of slight increase. It was interested that minute ventilation increased slightly in normal and cardiac groups during oxygen inhalation. 2) Arterial oxygen saturation In all cases arterial oxygen saturation increased during high oxygen inhalation. 3) Arterial carbon dioxide tension There was no significant change in normal and cardiac groups. However, the pulmonary group showed a slight increase of arterial carbon dioxide tension during 100% oxygen inhalation. The average increase was 3.6 mmHg in emphysema and 1.8 mmHg in the other pulmonary patients. II Changes of circulatory hemodynamics A. Pulmonary circulation 1) Cardiac index There was no significant change in normal group. While also no significant change in the pulmonary group of 40% oxygen inhalation was found, there was slight increase of the cardiac index in that of 100% oxygen inhalation, which was within a range of -1.21 to 1.25 (average + 0.23)1 /min/M² in emphysema and -0.13 to 0.95 (average+0.27)1/min/M² in others. On the other hand, patients with cardiac diseases showed a slight decrease within a range of -2.88 to 0.27 (average --0.85)1/min/M² during 40% oxygen inhalation and - 1.78 to 0.38 (average -0.49)1 /min/M² during 100% oxygen inhalation. 2) Pulmonary artery wedge pressure (WP) In normal group, pulmonary artery wedge pressure changed with 2 mmHg or less in all cases. In the pulmonary group of 40% oxygen inhalation, patients with emphysema showed a decrease of WP within a range of - 3 to 1 (average - 1.3) mmHg and others - 7 to 6 (average -0.1)mmHg. Of 100% oxygen inhalation, the former showed a decrease within a range of -5 to 0 (average -2.2) mmHg and the latter only - 5 to 5 (average -0.7)mmHg. In the cardiac diseases group WP rose 1 mmHg on an average during 40% oxygen inhalation and remained unchanged during 100% oxygen inhalation. 3) Pulmonary artery pressure (PAP) In normal group, decrease of the pulmonary artery mean pressure (PAm) was within a range of -3 to 1 (average - 1.1)mmHg during 40% oxygen inhalation and -4 to 1 (average -2.2) mmHg during 100% oxygen inhalation.

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The characterisitic configuration of the action potential of the cardiac muscle cell is its long sustaining "plateau" phase. The variations in the cardiac action potential duration produced by the changes in the frequency of stimulation are principally accounted for by the variations in this phase. The relationship between the action potential duration and the stimulation frequency is expected to shed some light on the problem of QT duration in ECG at various heart rates. The influence of the stimulus frequency on the electrical activity of heart muscle cell were studied with the ultramicroelectrode technique at varying conditions of medium extracellular fluid. Material and method. The resting and action potentials of the cardiac ventricular muscle of tortoise (Clemmys japonica) were recorded with the LlNG-GERARD type microelectrode. To overcome the disturbances due to vigorous mechanical movements, flexibly mounted suspending electrodes with copper wire of about 40μ in diameter and 20 cm long were often used. The composition of the reference medium solution was as follows : NaCl 136.8 mM/L, KCl 2.94 mM/L, CaCl₂ 1.84 mM/L, NaHCO₃ 2.5 mM/L, and pH was adjusted to 7.3. Results and comments. 1) There is always stable relationship between the interval of impulses and the action potential durations, which can be described as an exponential function. The results of the experiments are consistent with the expression derived by Carmeliet from the experiments on frog cardiac muscle. At the same time, at least in a certain range, the relation between the impulse frequency and the action potential duration could be described as a straight line. Except in the refractory phase, these relationships are very stable and are exactly reproducible. It is inferred that the variation of action potential duration with the changes in impulse frequency is on a fairly stabler cellular mechanism. 2) The changes in action potential duration depend chiefly on the changes in the duration of the second phase ("plateau" phase) of action potential. In the case of tortoise, there are changes in the third phase of action potential too, which is not found in the case of frog. 3) There is another regularity between the action potential duration and its preceding resting phase duration, which could be observed even when the regularities between action potential duration and interval of impulses and/or impulse frequency are lost in irregular excitation with intensively frequent impulses. 4) In a solution with high concentration of KCl, the variation of action potential duration with the change of impulse frequency is more marked and in the solution with low concentration of KCl milder, Besides NOBLE'S postulation that, at high stimulation frequency, the succeeding action potential would start at a time when the raised K permeability of cellular membrane due to the foregoing one is yet high, it may be supplemented, at high extracellular K concentration, by the possibility that, because of the raising activity in K permeability of high K bathing solution, the late component in the rise of K permeability at the active cellular membrane might be accelerated during repolarization, with consequence of the more intense shortening of action potential duration at frequent impulses. 5) The degree of the. shortening of action potential duration for frequent impulses is marked in a solution with high concentration of NaCl and is mild in a solution with low concentration. It is postulated that the increase of extracellular Na ions influences upon the K permeability of cellular membrane and accelerates the repolarization phase. 6) The degree of the shortening of action potential duration is mild in a solution with high concentration of CaCl₂ and marked with low concentration of CaCl₂. [the rest omitted]

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The disturbance of lipid metabolism has been regarded as one of the important factor in the etiology of atherosclerosis. It is thought that the ability to remove rapidly the absorbed fat from the blood stream is important to prevent the development of atherosclerosis. From this point of view, following observations were carried out. Method The subjects of observation were divided into three groups. Group I consisted of 10 young and healthy persons, group II of 18 aged patients with atherosclerotic diseases and group III of 6 old and clinically normal persons. To these subjects 100 gm of raw oream which contained 25% of fat was orally given early morning after overnight fasting. Then the blood samples were taken immediately before and 30 min., 1, 2, 4, 6, 8 hours after fat intake. Plasma separated from these samples were supplied to determine the optical density and the endogenous lipolytic activity. In each samples, the optical density (O.D.) was measured by the electro-spectrophotometer and the endogenous lipolytic activity (E.L.A.) was determined by the difference of content of nonesterified fatty acid (NEFA) prior to and after the incubation of each plasma at 37°C for 60 min.. NEFA content in plasma were measured by the Dole's method and indicated by rEq/ 1. Sometimes, NEFA content in plasma were observed to decrease and in such cases the E.L.A. were indicated by minus values. Result 1) Variations of O.D. in plasma following the oral fat loading The O.D. value of all cases in each group were increased following the oral fat intake and then gradually decreased after reaching to its maximal value. The differences of maximal value of O.D. among three group were not significant. It was observed, on the other hand, that O.D. was delayed in group II to reach its peak and also to recover from its peak compared with the other groups. 2) Variations of NEFA in plasma following the oral fat loading. NEFA content in plasma was gradually increased after the administration of fat in each group, but the obvious differences were not found in the degree of increase among three group. 3) Variations of E.L.A. in plasma following the oral fat loading. A certain degree of E.L.A. was occasionally demonstrated even before the fat intake in each group and mean value of them were 166, 57 and 100 respectively, but there were no significant differences among three group, because its variations were considerably wide. On the other hand, differences of E.L.A. patterns among three groups were very significant. Most cases of group I revealed their E.L.A. increased at the time from 30 min. to two hours after the fat intake and then gradually decreased, but not the minus values. On the contrary, there was few cases in group II, which showed a initial elevation of E.L.A. and many cases of this group indicated the remarkable depression of their activity and frequently showed the minus values of them. E.L.A. pattern in group III showed the mid-type of the other two groups. From these results it is demonstrated that E.L.A. in atherosclerotic patients hardly increase after oral fat intake, then markedly depress and is apt to show minus value compared with control groups. 4) Correlation between the pattern in O.D. and E.L.A. The pattern in O.D. were divided into two types, that is, normal type and delayed type. The former showed its peak within 4 hours after fat intake and the latter showed its peak later than 6 hours after fat intake. Most cases in group I showed normal type in O.D. and plus activity in E.L.A. 4 hours after fat intake. However, in group II, most cases showed delayed type in O.D. and minus activity in E.L.A. 4 hours after fat intake. The pattern in O.D. were also divided into normal and delayed type by the degree of recovery from its peak in two hours. In normal type the O.D. [the rest omitted]

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