The fibrinolytic activity of the endothelium of blood vessels in guinea pig and rat was demonstrated by histochemical and chemical procedures. The activity might be due to plasmin activator since the endothelium did not show any activity with heated fibrin. It was weak in the proximal aorta which has prevalance of atherosclerosis in rodent, and progressively stronger down the length of the aorta. Strongest activity was observed in the vein. The endothelium of rabbit, most susceptible animal to experimental atherosclerosis did not show any lytic activity against either bovine or rabbit fibrin. Role of fibrinolytic activity of the endothelium on atherosclerosis was discussed.

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Plasma lipid levels in subjects consuming large amount of fish consistently as their natural diet were examined in comparison with those in subjects consuming low fat diet and high animal fat diet. Age distribution is comparable in all groups and total calorie intake in all groups was at a level compatible with maintenance of lean body mass without obesity. Statistical analysis indicated that the fish oil is an excellent source of unsaturated fat.

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So-called pulmonary P has been described, and discussed by many investigators, but as to criteria of pulmonary P, there are still some different opinions. The purpose of this study was to investigate the relationship between the magnitude of the P waves and the disturbances of the pulmonary hemodynamics, especially pulmonary hypertension, in patients with chronic pulmonary diseases. Material and Method : Ninety patients with chronic pulmonary disease (62 cases with pulmonary emphysema, 12 with bronchial asthma, 3 with silicosis, 3 with bronchiectasis, 2 with pulmonary tuberculosis, 2 with lung tumor, 2 with pulmonary fibrosis, one with primary pulmonary hypertension, one with pyothorax, one with chronic bronchitis, and one with pulmonary sarcoidosis) were studied. Electrocardiograms of routine 12 leads were recorded just before the right heart catheterization. Results : The incidence of P waves with heights of above 0.2 mV in all of leads II, 111, and a_VF increased with elevating pulmonary artery mean pressure (PAm). However, such P waves were observed in 12.5 per cent of cases without pulmonary hypertension. When P waves were 0.25 mV or more in lead II and above 0.2 mV in leads III and a_VF, such a'. combination of P waves was more closely correlated with PAm than the other type of P waves, and was defined as "pulmonary P" in this study. It was found that 60 per cent of cases with PAm over 30 mmHg, 25 per cent of cases with PAm of from 20 to 29 mmHg, 10 per cent of cases with PAm of from 17 to 19 mmHg, and none of cases with PAm below 16 mmHg showed this pulmonary P. Among the cases who had the pulmonary P, PAm was measured in 1 5 cases, right ventricular systolic pressure (RVs) in 10, right ventricular end-diastolic pressure (RVd) in 6, right atrial mean pressure (RA) in 7, pulmo-nary vascular resistance index (PVRI) in 1 1, total pulmonary resistance index (TPRI) in 9, and the average values of these were 30.2 mmHg, 41.8 mmHg, 6.0 mmHg, 3.4 mmHg. 488.1 dynes, sec, cm<-5>/M2, and 743.0 dynes, sec, cm<-5>/M2 respectively. On the other hand, among the cases who did not have the pulmonary P, PAm was measured in 75 cases, RVs in 43, RVd in 48, RA in 33, PVRI in 46, and TPRI in 46, and the average values of these were 19.1 mmHg, 27.1 mmHg, 3.9mmHg, 2.5mmHg, 285.3 dynes, sec, cm5<ookikutsur ^-5M², and 440.6 dynes, sec, cm^-5/M² respectively.

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The theoretical explanation of the genesis of electrocardiographic T wave is subjected to one of the most perplexing points of debate. Various hypotheses to give its explanation have been proposed by different investigators, however, their explanations would seem to be rather inadequate as compared with that of the genesis of QRS complex. For the electrical activity of the heart during depolarization, its electrical source can be equivalently represented by the electrical double layer at the border of activation wave front. Furtheremore, the activation process during depolarization can be determined by means of the intrinsic deflection on the relevant electrocardiogram, when the tracing of a unipolar or contiguous bipolar lead is obtained from the surface of the heart or from the intramural cardiac mass. On the other hand, at the time of repolarization, there is no discernible intrinsic deflection to be registered by the extracellular lead, therefore, the repolarization process can not be easily investigated by any electrogram recorded extracellularly. At the present time, the re-polarization process can be observed only at the limited portion of the heart, that is, at the individual cardiac muscle fiber of the subepicardial layer by means of the intracellular microelectrode technique. In this study, using the tracing of repolarization phase of transmembrane action potential, the electromotive force during repolarization was discussed, and the construction of normal T wave was carried out, by using the speculated difference in pattern of the transmembrane action potential of cardiac fiber in the various layers of the heart muscle. Theory and Computation : It is considered that the electrocardiogram is the total sum or the superposition of the action current generated by individual excited cardiac muscle fiber, which is a spatial and time-varying function. The transmembrane action potential of its fiber can be registered by means of microelectrode method, although its action current can not.

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The thiazide derivatives and the aldosterone antagonists have been used widely as the anti-hypertensive drugs in recent years, though the mechanism by which they lower high blood pressure remains obscure. It can be assumed that the alterations in electrolytes distribution induced by the drugs play an important role in their hypotensive action. However, very limited works have been reported concerning the effect of thiazide derivatives and of the aldosterone antagonists on electrolytes distribution in human subjects and experimental animals. Moreover, among investigators there have been shown a consider able discrepancy of this project. It thus appears to the author that further precise investigation is necessary to determine the electrolytes distribution in plasma and red blood cells after the administration of those drugs in hypertensive subjects. Materials and Methods Fifteen hypertensive subjects without evidence of cardiac or renal failure were selected for the study. Seven patients received I mg of polythiazide twice a day and 8 patients received 50mg of triamterene four times a day for four weeks. Sodium, potassium, chloride and bicarbonate concentrations in plasma, and sodium and potassium concentrations in the red blood cells were determined before and every one week after the treatment for four weeks. The red blood cells were separated by centrifugation at 3, 600g for 30 minutes. Result Serial changes of electrolytes concentration in plasma and red blood cells in the polythia-zide group: Sodium concentration in plasma slightly decreased after the treatment, but its change was not significant. Potassium and chloride concentrations decreased significantly. Bicarbonate concentration rose significantly. Sodium concentration in the red blood cells significantly increased and therefore the ratio of plasma sodium to sodium in the red blood cells, Na^e/Naⁱ, significantly decreased. Potassium concentration in the red blood cells had no remarkable change but the ratio of potassium in the red blood cells to plasma potassium, Kⁱ/K^e, significantly increased. These changes were prominent mostly two weeks after the treatment and then returned to the pretreatment levels in the 4th week of treatment. Interestingly there was a close relationship between changes in Na^e/Naⁱ or Kⁱ/K^e and bicarbonate concentration.

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It is a well known fact that the thiazide derivatives and their analogues produce more or less metabolic alkalosis in the subjects treated with them. Concerning the relationship of acidbase equilibrium to the regulation of blood pressure, however, we have had only a few reports. Since this prblem seems to be important to elucidate the hypotensive mechanism of the thiazide derivatives, the author attempted in the present study to determine the influence of metabolic alkalosis induced by intravenous in-fusion of sodium bicarbonate solution on blood pressure in the hypertensive subjects. Materials and Methods One hundred and fifty ml of 7 per cent sodium bicarbonate solution was infused intravenously in 10 hypertensive subjects. Blood pressure was estimated before and every 5 minutes after the infusion of bicarbonate solution, for I hour. Arterial blood pH, sodium, potassium, chloride and bicarbonate concentrations in plasrna, and sodium and potassium concentrations in the red blood cells were estimated before and 30 minutes and I hour after the infusion. Results Arterial blood pH markedly rose after the intravenous infusion of 7 per cent of sodium bicarbonate solution. Systolic and diastolic blood pressures progressively fell in all subjects. Both systolic and diastolic blood pressures showed minimum levels 30 minutes after the infusion and then gradually returned to near the pre-infusion levels. Only the decrease in diastolic pressure was significant statistically 30 and 35 minutes after the infusion. Sodium concentration in plasma slightly increased whereas potassium concentration showed a gradual decrease. These changes, however, were not significant. Bicarbonate concentration significantly increased and chloride concentration decreased but the latter change was not significant. Sodium concentration in the red blood cells slightly increased and the ratio of plasma sodium to sodium in the red blood cells decreased. But both changes were not significant. Potassium concentration in the red blood cells had no change. The ratio of potassium in the red blood cells to plasma potassium increased though its increase was not significant. Discussion DRIPPS and COMROE have reported that respiratory acidosis induced by the inhalation of C₂ gas raise blood pressure in normal subjects. This finding is contrary to PAGE & OLMSTED'S observation that it lower blood pressure in normal dogs. On the other hand, WALDON and GOLDSTEIN and WELLER have noted a tendency of respiratory acidosis in the patients with essential hypertension. Because of these conflicting information, it is interesting to investigate the relationship of the alteration in acid-base equilibrium to blood pressure, especially with reference to the hypotensive mechanism of the thiazide derivatives which often disturb acid-base equilibrium to some extent. In the present study it was demonstrated that metabolic alkalosis induced by intravenous infusion of sodium bicarbonate solution lower systolic and diastolic blood pressures in the hypertensive subjects. It is, however, difficult to say whether the decrease of blood pressure following the infusion of bicarbonate solution is induced directly by metabolic alkalosis itself or indirectly through the alterations in electrolytes distribution accompanied by alkalosis. So far it would appear likely that metabolic alkalosis itself lowered blood pressure directly, since the alterations in electrolytes distribution induced by alkalosis were significant. Summary Intravenous infusion of sodium bicarbonate raised arterial blood pH and lowered gradually systolic and diastolic blood pressures in hypertensive subjects. Alterations of electrolytes distribution were not significant.

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Many investigators failed to demonstrate vasa vasorum in the inner third of media in aortic wall with routine histological techniques and it had been believed that the inner third of media may be an avascular area and the nourishment of this area may mainly be provided by the blood running through the aortic lumen. Recently, the introduction of microangiographic technique enabled the study of microcirculation in the vessel wall instead of routine histological technique. J. A. CLARKE, using an X-ray microscopic technique, demonstrated vasa vasorum of human thoracic aorta, revealing the patterns of distribution to the inner third of media just beneath the internal elastic lamina. The purpose of this paper is to describe a finding on the patterns and distributions of vasa vasorum in the aortic wall of dog. Materials and Methods Twelve healthy male dogs weighing 8.5 to 1 3.5kg anaesthetized with sodium pentobarbiturate (5 w/v% 10ml. i. v.) were used. Before the sampling of aortic specimen sodium heparin (500unit/kg) was injected intravenously. The abdomen was opened, the jejunum and ileum were retreated out of the way, and the vena cava inferior and the abdominal aorta were carefully isolated from the surrounding tissues. The both vessels were ligated at the level L₂ to L₄, and each was proximally cannulated with polyethylene tube. All blood in the area under the study was removed by a through flushing with Ringer's solution containing heparin (200 units/ml) at 37'C. Fifty per cent Micropaque solution was injected under manual pressure into the aortic tube in a dose of 300ml at first and then into the venous tube in a dose of 200 ml. Five minutes later, the chest was opened and the aorta was extirpated quickly with the heart. The aorta was isolated and aortic lumen was washed with running water for 3 minutes. A 10 per cent neutral buffered formalin solution was used for the fixation of the material for 48 hours or more. After flxation, the aorta was made into cross or longitudinal section of 0.5 mm to Imm thick, and examined by X-ray microscope. A model of SOFTEX was used as an X-ray source. Exposure time varied 20 to 30 minutes depending on the thickness of specimen, at 7kV at 3mA.

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As shown in the previous report, we have succeeded in dernonstrating vasa vasorum in the innermost layers of media of the dog's aorta by an X-ray microscopic techniques. In the present study, electron microscopy was used to see the fine structure of vasavasorum and to see whether the histamine type of leakage (MAINO and PALADE, 1961) exist in the Vasa vasorum of the dog. Materials and Methods Six young and healthy male dogs, weighing 8.7-12.3 kg, were used. The dog was anaesthetized with 10ml of sodium pentobarbiturate. A dose of 2.5 ml/kg of carbon suspension (acting carbon Pelikan C11/143 1a) was injected into the cephalic vein of 3 dogs, and the aortic specimens were taken in situ 15 minutes after the injection. As a control, 2.5ml/kg of physiological saline was injected into the cephalic vein of another 3 dogs. Specimens of aorta were quickly removed from the surrounding tissue. The fixative was an I per cent aquous solution of osmium tetroxide with veronal buffer (pH= 7.4), which was brought to, isotonicity with 0.25 M of sucrose. This fixative was poured into the lumen of aorta, the specimen was cut into small blocks of about 1 to 2 mm x 3 to 4mm in size. The blocks were fixed for one hour under cold temperature in an ice-box and then dehydrated in serial changes of ethanol, and embedded in Epon 812 following the procedure of LUFT. The section was cut on a ultrotome-LKB stained with saturated aquenous solution of uranyl acetate. Electron microscopic photo-graphs were taken with a HITACHI-HU-11A microscope. Results 1. Fine filaments, about 50A in diameter, and small vesicles, 60mμ in diameter, were present in cytoplasm of almost all endothelial cells of the capillaries, arterioles and venules of vasa vasorurn. On the other hand myofilament-1ike structure are rare in the endothelial cells of aortic lumen. Some processes or microvilli were often seen projecting into the lumen of the vessel. Some of these microvilli or processes were actually small marginal folds and extended to the vessel lumen.

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