The action of histamine on the cephalic circulation was studied in unanesthetized rabbits. Histamine, when administered by intracarotid injection, elicited consistent decrease in blood flow through the internal carotid artery as well as through the external carotid artery. This result is against the generally accepted view that histamine is a potent vasodilator of the cerebral blood vassels.

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The lipid metabolism, especially Nefa oxidation to expired CO₂ and transfer to plasma triglycerides was investigated by using palmitic acid-1 -C¹⁴ with reference to glucose metabolism in arteriosclerotic, diabetic, hyperlipemic and control subjects. 1 ) In a fasting state, Nefa oxidation in the cells of an arteriosclerotic subject was twice as much as that in the control subject and transfer of Nefa into plasma triglycerides was 3 times in the arteriosclerotic, 2 or 3 times in the hyperlipemic, 2 times in the diabetic subject as much as that in the control subject. The Nefa oxidation rate in the cells of an arteriosclerotic subject was most increased to reach to 4 times and in the diabetics 2 times as much as that in the control subject. Rate of Nefa transfer to plasma triglycerides increased in both arteriosclerotic and diabetic subjects to 6 or 4 times as much as that in the normal subject. 2) Glucose loading increased the Nefa oxidation in the control, diabetic and male hyperlipemic subject, while decreased in an arteriosclerotic and a female hyperlipemic subject. By glucose loading the transfer of Nefa into plasma triglycerides was only slightly changed in the control, arteriosclerotic and diabetic subject, while was increased in the male hyperlipemic subject. By glucose loading the rate of Nefa oxidation in the cell was increased in the control and diabetic subject, while decreased in the arteriosclerotic subject ; then the rates became to almost same in all cases. The rate of Nefa transfer into plasma triglycerides in the arteriosclerotic and diabetic subject was decreased, while in the control subject was increased a little by glucose loading. 3) The Nefa oxidation was markedly or a little depressed in the control or arteriosclerotic subject respectively and unchanged in a diabetic subject by insulin administration. Insulin de-pressed the Nefa transfer into plasma triglycerides in the control and arteriosclerotic subject. By insulin administration, the rate of Nefa oxidation was unchanged in the arteriosclerotic and depressed in the control and diabetic subject ; especially, in the diabetic subject was most influenced. 4) In an arteriosclerotic subject, the accelerated Nefa oxidation in a fasting state was decreased to half by glucose administration and unchanged by insulin loading. Then, available glucose seems to be insufficient in the cells of arteriosclerosis. In a diabetic subject, Nefa oxidation was not increased in a fasting state and increased by glucose loading and unchanged by insulin loading. Then, insulin seems to be insufficient in the cell of diabetes mellitus. In a control subject, Nefa oxidation was accelerated by glucose loading and depressed by insulin loading. In an arteriosclerotic subject, Nefa transfer into plasma triglycerides was markedly accelerated in a fasting state ; this Nefa transfer was changed a little by glucose and decreased by insulin loading. In arteriosclerotic subjects, it would be suggested that disturbances in lipid metabolism may be partly caused by the deficiency of glucose metabolism. In a diabetic subject, Nefa transfer was moderately accelerated in a fasting state and slightly changed by glucose or insulin loading. In diabetes mellitus, glucose seems to have the direct influence, while insulin, the indirect influence through glucose metabolism, on lipid metabolism. In a control subject, Nefa transfer was slightly increased by glucose and markedly decreased by insulin loading.

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With an increasing interest in cor pulmonale, several factors influencing pulmonary hemodynamics have been investigated by many authors. Most of these authors have estimated the ventricular mechanical effect from minute mean value of both systolic and diastolic phases of the cardiac cycle. however, considering the fact that the maximum ventricular mechanical effect is performed at the ejection period during the systole and more particularly during the period when the semilunar valvular open, the measurement of the accurate ventricular mechanical effect should be obtained during the ejection period rather than during both systolic and diastolic phases as in previous works. In the present study, the author used three different vasopresser agents and analyzed various phases of pulmonary circulation. From these results, ejection time of the right ventricle, mean pulmonary pressure per ejection phase and the mechanical effects of the ejection were obtained and were compared with the results of previously described methods. Material and Method A total of 24 cases was used in this study including 3 cases of normal individuals, 16 cases of cardiacs, 4 with pulmonary diseases and one with hepatic disorder. A routine right heart catheterization was carried out with a double lumen catheter. The pressures of the right ventricle and pulmonar artery were measured with simultaneous recordings of both electrocardiogram and phonocardiogram. The subjects were divided into 2 groups according to their resting mean pulmonary arterial pressure. The group I of 11 cases showed their mean pressure not exceeding 11 mmHg, the group II, consists of 13 cases with mean pressure exceeding 18 mmHg. The blood gas analysis was carried out by the method of VAN SLYKE-NEIL and expired air was analyzed with SCHOLANDER'S gas analyzer. Cardiac output was measured by FICK'S method. The control pressure as first measured during room air breathing without drugs and the second measurement was carried out 15 to 20 minutes namely, 7-chlor-ethyl-theophylline (Cl. E. T.) intravenously (200 mg), 1.4 : 3.6-dianhy-drosorbitol-2.5-dinitrate (I. S. D. N.) sublingual (10 mg) and inhalation of 50 per cent O₂, and following measurements were made.

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[in Japanese]

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A. Age Difference in Arterial Blood Oxygen Saturation During a Period of Low Oxygen Air Respiration Attention has been called upon the fact that the degree of arterial blood oxygen saturation which serves as a criteria in the estimation of low oxygen air respiration may vary depending upon a number of conditions regardless of the same low oxygen air inspired. Considering this fact, the author has attempted to investigate this by statistically studying the data of arterial blood oxygen saturation during low oxygen air breathing. Method ; Estimation of arterial blood oxygen saturation (Sa_O2) during a period of 10% oxygen inhalation in various age groups composed of 46 healthy individuals were tabulated. Sa_O2 values were also, studied on another group of 20 healthy young adults during 10 ± 0.5% oxygen inhalation by venous catheterization. Results : (1) Without Venous Catheterization In the study of age relationship with the Sa_O2 values of 46 cases during 10 ± 0.5% low oxygen air inhalation without resorting to venous catheterization, a significant negative correlation, r=-0.66 (p <0.01), was obtained. The values of arterial oxygen saturation of respective age group were as follows : Young adult group (ages 20-39, 16 cases, average age 27.4) 74.0-5.4 per cent. Middle age group (ages 40-59, 11 cases, average age 50.4) 65.4 ± 7.1 per cent. Old age group (ages 60-78, 19 cases, average age 68.8) 63.6 ± 5.1 per cent showing a low value. (2) With Venous Catheterization The healthy young adults (ages 21-38, 20 cases, average 30.8) were studied under the same low oxygen inhalation with venous catheterization. The Sa_O2 value was found to be 62.6 ± 7.9 per cent, a definitely lower value when compared with that (74.0 ± 5.4 per cent ) of the none catheterized young adults. From the foregoing results, it was found that in the old age persons without venous catheterization, the Sa_O2 reduction was more marked than that of the young adults without catheterization and just comparable to that of the latter with catheterization.

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Phonocardiographic studies were undertaken on the patients with congenital and acquired heart diseases before and after cardiac surgery in hope that follow-up studies on the changes in heart sounds and murmurs might reflect the effect of surgery and normalization of cardiopulmonary function. Materials and Methods Twenty cases of atrial septal defect (ASD), 29 cases of ventricular septal defect (VSD), and 10 case of mitral stenosis (MS) were subjected to this study. Phonocardiograms were also taken in sixteen cases of normal individuals in order to obtain normal values (Table 1). A multifilter system phonocardiograph and microphone of dynamic type^* were used. Phonocardiograms were taken at a speed of 100 mm per second together with electrocardiograms. Responses of cardiac murmurs to amyl nitrite and phenylephrine were analyzed to differentiate the origin of murmurs before and after surgery. Right heart catheterization was performed before surgery in all cases and was repaeted one month after surgery in 10 cases of ASD, 10 cases of VSD and 8 cases of MS. Results 1. ASD Postoperative right heart catheterization study showed normal RV and PA pressure and absence of shunt in 8 cases out of 10, and per sisting elevation of RV and PA pressure with a residual shunt in the remaining 2 cases (Fig. 6). Q-I interval was slightly prolonged preoperatively and it returned to normal range within 1 month after operation. Two case with a residual shunt, however, still showed prolongation even 6 months after operation (Fig. 1). Apical first sound was accentuated in 16 cases before operation. Accentuation persisted, though in a decreased intensity, in 5 cases 1 month after operation, and in 3 cases 6 months after operation. The cases with a residual shunt showed a persistent increase in intensity of apical first sound (Fig. 2).

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The magnitude of pulmonary vascular resistance will be one of the important criteria for pulmonary circulatory function, because it elevates pulmonary arterial pressure to bring about pressure load in the right ventricle of the heart. It being, however, known that, at the pulmonary circulatory system, its anatomical features give some limitation to the application of POISEUILLE-HAGEN Law, the change of pulmonary vascular resistance cannot necessarily result in the active constriction or the dilatation of pulmonary vessels. Meanwhile, since lungs are always influenced with the change of intrapleural pressure, the influence by the change of respiration in terms of its depth or its pattern, should always be taken in consideration. In light of this, the author had the following experiments using normal dogs and experimental pulmonary-hypertension dogs as the subjects : (1) the inflation of intratracheal pressure under the intermittent positive pressure breathing. (2) hyperventilation (by using a body respirator) (3) hypoventilation-lowtidal ventilation-(by using a body respirator) (4) stellectomie (5) intervenous infusion of C₆ (6) vagotomy Through this experimentation, he observed the right ventricular function as well as how the change of each respiratory pattern mentioned in the above experiments affected pulmonary arterial pressure and pulmonary vascular resistance, and affected their regulatory mechanism. Materials and Mehtod As to both the normal dogs and the pulmonary-hypertension dogs (into the bronchi of which resin was infused), the circulatory dynamics, before and during the controlled respiration, and, before and during the blocking of the auto-nomic nervous system, were observed. In other words, the right ventricular function and the pressure-flow relationship in the pulmonary circulatory system were investigated using the cardiac catheterization method and the dye dilution method based on the modified BING-HOLZ method.

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