1. Intravenous infusion of isoproterenol (0.1 to 0.5μg/kg/min) in the dog produced a de-crease in GFR, RPF and urine volume, accompanied by a fall in systemic blood pressure. Urinary excretion of sodium, potassium and chloride significantly decreased. A dose of 0.5μg/kg/min resulted in a significant decrease in the urinary concentrations of these electrolytes, but a dose of 0.1μg/kg/min resulted in no change. Osmolal clearance decreased but free water clearance increased during the isoprotenol infusion. 2. When 0.01 to 0.05μg/kg/min of isoproterenol was infused into the left renal artery, GFR and RPF of the infused kidney increased with no changes in systemic blood pressure, while those of the opposite kidney remained unchanged. Being accompanied with diuresis, there developed an increased excretion of sodium, potassium and chloride in the in-fused kidney. Osmolal clearance increased, free water clearance decreased. These changes, but however, were not observed in the opposite kidney. 3. It is concluded that isoproterenol has a diuretic effect through its direct action on renal function and that the antidiuresis induced by this drug is mainly due to its systemic hemodynamic effect.

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In fourteen patients with aortic insufficiency, the interrelations among the systolic time intervals and other hemodynamic measurements were studied by means of cardiac catheterization and angiocardiography. The pre-ejection period was within the normal range in nine patients. The left ventricular ejection time and the total electromechanical systole were prolonged above normal in almost all the patients. The left ventricular ejection time corrected for heart rate exhibited a close inverse relationship to both the ejection fraction and the mean shortening velocity per unit length of the myocardium. These findings suggest that the left ventricular ejection time can be a non-invasive aid of clinical use in evaluating the left ventricular function in patients with aoric insufficiency.

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Ten μc of [1, 2-³H] testosterone was injected intravenously, as a single dose, to male intact, castrated, adrenalectomized and hypophyse-tomized rats. The lymph from thoracic duct was collected continuously at varing intervals for 160min after the injection. In all animal groups the intravenously injected hormone appeared in the lymph, with maximum radio-activity in the first five minute lymph specimen, and disappeared afterward at a very rapid rate. The pattern of appearance of radioactivity in the lymph was similar to that in blood circulation. A greater proportion of raioactivity appeared in the early 40minute lymph specimen. The values of cumulative radioactivity were higher in the lymph of both adrenalectomized and hypophysectomized animal groups than those of both intact and castrated ones. It was mentioned that the hypophyseo-adrenal axis might be responsible for this phenomenon. The estimated biological half-lives in the lymph were longer in castrated animals than those in the other groups. A possible reason for this was discussed.

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A cace of obstructive cardiomyopathy has been presented. A pressure gradient was evident across the outflow tract of both ventricles under resting condition. Angiocardiography showed marked hypertrophy of the interventricular septum which bulged into the right ventricle as well as into the left. Ventriculo-myotomy was carried out to relieve the obstruction. Special attention was directed to the ultrastructural findings of the resected myocardium, which showed dissociation of the intercalated disc. The condition offers addition-al support to the concept of "disease of the intercalated disc".

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Various techniques of induced cardiac arrest, which allows the surgeon a motionless and dry field for facilitating a safe and easy intercardiac surgery, have been deviced by a number of investigators. Induced cardiac arrest is at the same time useful for reducing or totally preventing the possibilities of air embolism into the coronary or cerebral circulation. A method of anoxic arrest induced by crossclamping the aorta above the valve, in combination with or without hypothermia, has been widely used. However, controversy continues as to whether myocardial hypoxia produced by anoxic arrest might severely impair postoperative cardiac performance in addition to any trauma caused by the operative procedure. Another generally used method for induced cardiac arrest is induced electrical fibrillation, which provides a non-contracting heart, maintaining it in the active state of ventricular fibrillation, though venous return from the coronary sinus and Thebesian veins may be some nusance to dry operative field. The author has adopted electrical ventricular fibrillation as an effective means of induced cardiac arrest and has originally devised an accurately operable fibrillator. Since its usefulness was observed as the results of some experimental studies on it, it has successfully been employed in clinical application. The purpose of this report is to describe some noticeable results of the experimental studies an clinical application, with some discussion. I. The apparatus The fibrillator deviced by the author can be used for applying an alternating current or a direct current, and is equipped with an ammeter, a timer and a voltmeter for measuring. Two types of the electrode are provided for use : in one of them each electrode is made of a stainless-steel disc, in another type one electrode is made of a steel disc and the other of a steel clip.

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Various types of assisted circulation have been classified into the following 3 groups according to indication for their applications, through the serial experimental and clinical studies by Akune and co-workers : assisted circulation (1) for right -sided heart failure, (2) for left-sided heart failure ; selective left ventricular bypass (SLVB) and synchronized arterial counterpulsation (SAC-P), and (3) for both left- and right-sided heart failure. The purpose of this paper is to report the investigation of the effects of SLVB and SAC-P, each being a method of assisted circulation for left-sided heart failure, upon the lungs in the view of changes in pulmonary water content and the histological findings. The experimental dogs were divided according to the method of assisted circulation into 3 groups : (1) SLVB group of 8 dogs, (2) SAC-P HB group of 12 dogs in which SAC-P was performed with an arterial cannula inserted via the innominate artery, and (3) SAC-P HAL group of 11 dogs in which SAC-P was performed using an arterial cannula inserted through the abdominal aorta. Moreover, in SLVB group, the experimental dogs were divided into 2 groups : group I of 3 dogs in which a vent to the left ventricle was used and group II of 5 dogs in which no vent was used. Each SAC-P group was further divided according to the results of hemodynamic performance : group I of SAC-P carried out under proper phasing and group II of SAC-P carried out under improper phasing. The author discussed the problems concerning the determination of changes in pulmonary water content and the method to excise a lung specimen for a histological examination. The change in pulmonary water content was determined by the method reported by Wood and Moe. A lung specimen was excised from the segment of the lingular or left lower lobe. Regarding to the histological study hyperemia, congestion, exsudate in alveoli and edema around pulmonary arteriole were specially examined by the staining of hematoxylin-eosine.

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