Studies on influence of gravity between the supine and the upright distributions of regional pulmonary arterial flow indicated that cardiac and pulmonary diseases were divided into three groups according to impaired pulmonary circulation. In severe cases with pulmonary vascular d, isorders showing marked pulmonary hypertension and probably indicating the organic changes in pulmonary vessels, both gravitational change and change ratio were extremely decreased ; these cases were called "perfect form of impaired pulmonary circulation". There were the cases with decreased gravitational change but normal gravitational change ratio; these cases which may have elevated intravascular pressure but keep some distensibilities of vessels were called "imperfect form". There were of course the cases with the same gravitational change and change ratio as those of normal subjects ' these cases with normal hemodynamics were called "normal form". Further study on upper to lower ratio, correlating with pulmonary venous pressure, was able to divide perfect form into two groups. This suggested that postcapillary pulmonary hypertension might be differentiated from precapillary hypertension.

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An isolated canine heart perfused with Tyrode solution was put into the human torso model filled with the electrolytic solution and the electrical center of the heart was determined by application of the cancellation method and the equivalent dipole moment during depolarization was calculated. Electrocardiograms recorded through the Frank lead system and the precordial leads were compared with those synthesized from the scalar product of the dipole moment and the transfer impedances of these leads. The discrepancy between actual and synthesized electro-cardiograms was regarded as the nondipolar fraction of electrocardiogram. This fraction amounted to far higher percentage of electrocardiographic deflection in leads V₂, V₃ and V₄ than in leads V₁, V₅, and V₆ and the Frank lead system. Therefore, it was concluded that leads V₂, V₃ and V₄ contained much information about the nondipolar component of electromotive forces of the heart which was not contained in the Frank lead system.

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1. Increased activities of serum enzymes were observed after application of DC countershock in 4 of 6 patients. The elevated levels of serum transaminases were found after countershock in 2 patients with serum hepatitis, especially GPT more elevated than GOT. 2. Using the indwelling catheter in three positions in canine experiments resulted in the assumption that the increased levels of plasma enzymes might be derived mainly from hepatic vein in 2 dogs, from coronary sinus in one dog and from superior vena cava in one dog. 3. It is suggested that a small rise of serum or plasma enzyme activities after application of DC countershock originates mainly from myocardium, from hepatic tissue and from skeletal muscle. 4. Atrial fibrillation recurred 2 weeks after reversion in one patient who had not received quinidine sulfate, while a sinue rhythm has persisted after reversion in another patient without administration of quinidine sulfate. 5 . The transient electrocardiographic changes after application of DC countershock were the following : atrial or ventricular premature beats, ventricular bigeminy, nodal rhythm, depressed or elevated ST segment and inverted T wave. The distinctly elevated ST segment immediately after application of DC counter-shock was concave facing upwards and returned to the isoelectric line 3 minutes later in one patient who showed simultaneous ventricular bigeminy. 6. Serum potassium values were increased after application of DC countershock in 2 of 4 measurements, while serum sodium value was decreased concurrently in one of them. 7. Cardiac output and stroke volume were increased after cardioversion in the cases measured.

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H³-thymidine labeled lymphocytes from thymus and from lymph nodes of donor rats were washed and injected into the intestine of recipient rats. Measurements were made on radioactive fraction in portal vein serum and in thoracic duct lymph plasma at various times after injection. The DNA-H3 was detected in blood serum and in lymph plasma. Absorption of the labeled materials at nucleoside and nucleotide levels occurred simultaneously. These results suggest that lymphocytes which, under physiological conditions, migrate into the gut can serve as a source of material for synthesis of new DNA after digestion within it.

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There have been many contraversies or disputes concerning to the hemodynamic mechanism of the development of the first sound and splitting of the second sound. Still many arguments are present whether the first heart sound is developed simply by the vibratory movements of the valvular leaflets or with cardiac muscular tonic vibration. It has been well known that the prolonging diastasis increases the filling volume from atria to ventricle which may affect the modes of ventricular isometric contraction and also the ventricular premature beats, either induced experimentally or clinically, interrupt any points of the time during diastasis and may result in abnormally delayed intraventricular conduction. The purpose of this paper is to study the hemodynamic mechanism for the development of first and second heart sound in case with variable R-R interval because of the occur rences of vent.ricular premature beats induced experimentally in dogs by mechanical or electrical stimulation to the both ventricles or in clinical cases. A) The author has studied the Q-I time, amplitude and splitting of Ist soundin a series of dogs with experimentally induced premature ventricular contractions, as mentioned about. Q-I time equivocally prolonged which has been attributed to the effects of electrical as well as mechanical delay of the onset of ventricular contraction. Succeeding isometric contraction period also prolonged. The amplitude of the Ist sound appeared to show positive correlation to the preceding diastolic period, which also suggested the presence of positive correlation between the amplitude of Ist sound and ventricular filling volume. In case with extreme short preceding R-R interval, the amplitude of Ist sound was significantly reduced and the succeeding ventricular ejection was failed to take place. These observations suggest cooperated action between vibrations of valvular leaflet and myocardial tonic vibration in establishing the Ist heart sound.

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The mechanism of the elevation of the blood pressure in hypertension caused by renal artery constriction in animals is generally thought to occur by release of renin in acute stage, but on the results in chronic stages one doesn't come always to an agreement. This study was undertaken to show a possible role of renin-angiotensin-aldosterone sys-tem in chronic stages of the experimental renal hypertension. For this purpose, the following experiments were examined, using Goldblatt's rats in each period of chronic stages, that is, 3-4th month, 5-6th month and 18th month : determinations of renin content of the kidneys and production rate of aldosterone in adrenals, in relation to Juxtaglomerular index (J. G. index) of kidneys and histological findings of kidneys and adrenal cortex. Materials and Methods. Adult male rats of the Wister strain weighing about 150 g were applied with clips to each left renal artery in order to produce persistent hypertension. The rats were maintained on a standard chow (M.F. ) of "Oriental Enzyme Co." (in Japan) in our laboratory during 3 to 18 months. The blood pressure was determined by the tail plethysmography. Renin-extraction from the kidney was performed according to HAAS & GOLDBLATT'S method (1954) (Fig.1) and LEVER'S mothod (1964) was employed in preparing renin substrate from dog's plasma (Fig. 2). Renin extracts were bioassayed by rats after the incubation with the substrate by means of SCHAFFENBURG'S method (1960) (Fig.3). Aldosterone production rate of adrenals was determined by our double isotope derivative dilution method (ISHIBASHI'S method, 1967) (Fig. 4). Histology of the kidneys and adrenals was observed by the hematoxylin-eosin staining, and also adrenal cortex was observed by electron-microscope. Results The mean blood pressure of our experimental rats ranged from 150 to 180 mmHg after constriction. Renin content of the rat kidneys in 3 to 4th month after clamping increased and that of the contralateral kidneys decreased, when compared with that of controlled rats. There was a similar tendency in the rats in 5 to 6th month and 18th month (Fig. 5, Fig. 6). J. G. index of clamped kidneys increased and that of contralateral kidneys decreased in each of all chronic stages. Aldosterone production rate of adrenals increased, when compared with that of controlled rats in each of all chronic stages (Fig. 5, Fig. 6). In the histological observations, the kidneys showed sclerotic changes, especially in the clamped kidneys on 18th month of Goldblatt's rats (Fig. 7, Fig. 8, Fig. 9, Fig. 10). In adrenal cortex, hypertrophy of zona glomerulosa was demonstrated, especially in 18th month (Fig. 11, Fig. 12).

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Since the experiments conducted in 1950 by WALTON and his co-workers in direct measurement of the isometric ventricular contractile force of the myocardium, several problems in this field have remained unsolved. Among these is the development of an efficient recording system for measuring these factors in living animals. This paper sets forth the results of the author's experiments aimed at developing such a system. The fundamental studies for this report were made on frogs and toads and were for the purpose of determining the influence of the pulse rate on the action potential and the contractile force of the myocardium. Method The toad was anesthetized with chloroform and placed in an upside-down position. The heart was exposed and its longitudinal contractile force was recorded by the suspension method. Needles were inserted at two points on the surface ofthe myocardium to record the action potential. The frog's heart was removed and a cross-section cut out. The cross-section was then cut in one place and stretched into an oblong. The strip wasthen place in a sepa-ration chamber filled with Ringer's solution. The tension was measured by a wire straingauge and the action potential was recorded by means of non-polarizable electrodes on both sides of the partition. The dog was anesthesized with thiopental-Na and the chest was cut open. The legsof a tiny metal bridge to which were attached semi-conductor strain-gauges, were fixed directly to the ventricular surface with a silk thread or Aron Alfa (α-ciano aclylate) paste. Using this method, the tension curve of the local myocardium was recorded. At the same time the left ventricular pressure curve, ECG and direnct-ECG were recorded. (Note: When artificial stimulation was used in these experiments, square wave pulse stimulation was employed.) Results & Summary 1) In the experiments conducted on frogs and toads, as the interval between the two stimuli approached a certain point, usually 1-1.2 sec., the second tension curve rose rapidly ; after that, as the interval increased, the tension curve tapered off gradually. In the action potential, the longer the interval between the two stimuli, the greater the second action potential. The point at which the action potential ceased to increase rapidly was found to be the same point at which the tension curve began to decrease from its highest point, i.e., 1-1.2 seconds between stimuli.

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