The four auricular arrhythmias, premature systoles, paroxysmal tachycardia, flutter, and fibrillation, have been investigated in over 200 dogs by three methods: (1) high speed cinematography, (2) cathode-ray oscillography, and (3) multiple-channel electrocardiography. The hitherto unexplored body of the left auricle has been surgically exposed and thoroughly studied. Results indicate that all four arrhythmias are of unitary origin and may occur from one ectopic focus. The resulting arrhythmia depends largely upon the rate of discharge from that focus. There is no circus movement. Corroborative observations have been made on the arrhythmias in man. This conception of the auricular arrhythmias simplifies the understanding of their mechanism.S INCE the classic studies of Lewis and his associates' on the nature of the auricular arrhythmias, comparatively little has been published on this phase of the subject. Levi is believed that his experiments established the following concepts concerning the mechanisms of the auricular arrhythmias:1. That auricular flutter is due to a regular circus movement in the auricles which sweeps around the openings of the venae cavae. The main impulse usually travels in a counterclockwise direction up the right auricle, circling the superior vena cava, then down the left auricle, and around the inferior vena cava, thus completing the circus. Regular daughter waves are sent off the main wave to the remainder of the auricles.2. Auricular fibrillation is due to a circus movement of the same general type as that of auricular flutter, but in this instance the impulse pursues a tortuous and redundant path around the venae cavae and sends off irregular daughter waves to the remainder of the auricles.3. Paroxysmal auricular tachycardia is of a different nature. Lewis believed that a rapidly discharging ectopic focus in the auricle is responsible for the arrhythmia; no circus movement is present. Other investigators, however, do favor circus movement as the mechanism of auricular tachycardia. The evidence that Lewis gathered with regard to circus movement appeared so complete that his conclusions have been accepted as fact in most modern textbooks of physiology, cardiology, and medicine.For the past three years we have been taking high-speed, colored cinematographs of the auricles of the intact dog's heart. A Western Electric Fastax 16-mm. camera was used with which films were taken at speeds up to 2,000 frames per second. When films taken at 2,000 frames per second are projected at eight frames per second the motion of the auricles is slowed 250 times. Auricular events that occur in one second take four minutes to view on the screen. A magnifying lens is used which enlarges the auricle 100 or more times on projection. By careful photographic technic, and lighting the field with twelve RSP-2 photospot incandescent lamps, excellent pictures are obtained showing the most minute detail of auricular activity. By means of such pictures, the auricular contraction wave can actually be seen for the first...
Proteinuria may be produced in the experimental animal in a variety of ways. One of the simplest and most convenient methods is injection of the kidney enzyme, renin.Picketing and Prinzmetal (1) were the first to notice that proteinuria was increased following renin administration to the rabbit. Brandt and Gruhn (2) confirmed this finding, and by studying the simultaneous excretion of injected hemoglobin, concluded that renin does not significantly alter the glomerular permeability, but rather increases proteinuria by diminishing tubular reabsorption of protein from the glomerular filtrate. Shortly after this, Addis, Barrett, Boyd, and Ureen (3) discovered that renin produced an intense, though transient, proteinuria in the rat. Since inactivation of renin, with respect to its pressor effect, led to a loss of its capacity to induce proteinuria, and since repeated injections of renin, at suitable intervals, led to a diminution in the proteinuric as well as the pressor property of renin, these workers concluded that this form of proteinuria is dependent on the pressor action of renin. Rather and Addis (4) reported that the athrocytosis of simultaneously administered hemoglobin or bovine albumin by the cells lining the proximal convoluted tubule is not inhibited by renin, and stated that Brandt and Gruhn's hypothesis, that renin inhibits the tubular reabsorption of protein, is not supported by their experiments. More recently, Lippman, Ureen, and Oliver (5) have restudied the effect of renin on the excretion of injected hemoglobin. From a combination of morphological and functional data these workers conclude that renin causes an increase in glomerular permeability to hemoglobin and decreases the tubular reabsorption of this substance. Hence, conflicting views are expressed concerning the mechanism whereby renin produces an increased excretion of protein in the urine.
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