Alberto C. Taquini

Behavior of the Right Ventricle Following Acute Constriction of the Pulmonary Artery

In 15 anesthetized dogs, constriction of the lumen of the pulmonary artery by less than 50 per cent produced no significant change in intraventricular pressure or cardiac output. Additional constriction caused a progressive increase of the right ventricular pressure; up to a pressure of 62.3±3./min. Hg, there was no change in cardiac output. With higher right ventricular systolic pressure there was a reduction in cardiac output, gradual decrease in systolic pressure but increase in diastolic pressure of both ventricles, and ultimately dilatation of the heart and ventricular arrest or fibrillation.

Phonocardiographic studies of early rheumatic mitral disease

Abstract Clinical experience has shown that patients with rheumatic mitral valve involvement of less than one years duration always have an apical systolic murmur of at least moderate intensity. In addition, they frequently have in diastole a moderately loud extra sound or a rumbling murmur. Phonocardiograms were taken synchronously with electrocardiograms or tracings of the venous pulse or apical pulsations in fifteen unselected cases of early rheumatic mitral involvement. From these studies we have concluded that: 1. 1. The audible extra sound appears, in the phonocardiogram, as a series of vibrations which occur at the moment when the left ventricle is distended by rapid inflow, and is therefore a real third sound. 2. 2. In some cases, prolongation of the vibrations of the third sound may produce the acoustic effect of a rumble. 3. 3. In other cases, the vibrations of the auricular sound which occur very shortly after, or are superimposed upon, prolonged vibrations of the third sound enhance the acoustic effect of a rumble.

The Renin-Angiotensin System in Different Stages of Spontaneous Hypertension in the Rat (S H R)

The present study analyzed the concentration of renin-like activity and angiotensinogen concentration (AoC) in different brain areas related to cardiovascular control in SHR and Wistar Kyoto (WKY) animals. Male rats of both strains were studied at 8, 16 and 30 weeks of age. The following brain areas were isolated: anterior, medial and posterior hypothalamus, septal area, periaqueductal gray (PG) and the remaining brain stem; nucleus tractus solitarius (NTS) and the remaining medulla oblongata. Plasma renin activity (PRA) and plasma and cerebrospinal fluid (CSF) AoC were determined. Renin-like concentration was higher in SHR than in WKY in the anterior hypothalamus, PG and NTS at different stages of hypertension development. AoC was also higher in some areas of the SHR brain during different periods. PRA, plasma and CSF angiotensinogen concentration showed significant differences between both strain of rats during the development of high blood pressure. Present data support the possibility that the central and peripheral renin-angiotensin system may participate in the maintenance of high blood pressure in the SHR animals.

Fat embolism of the lungs

Abstract A case of accidental oil pulmonary embolism producing shock and pulmonary edema is presented. Cardiorespiratory function studies showed hyperventilation, anoxemia, and pulmonary arterial hypertension with increased blood flow. Supportive treatment with noradrenaline, oxygen, and adrenocorticotrophin resulted in complete recovery.

Studies on the Renal Humoral Mechanism of Chronic Experimental Hypertension

The renin content of the kidneys from chronic renal hypertensive dogs rises when the kidneys are transplanted to the neck of a normotensive nephrectomized animal. This elevation precedes and accompanies the elevation of the blood pressure of the recipient. This type of experiment does not allow one to draw conclusions concerning the humoral mechanism of chronic renal hypertension.

The Brain Renin—Angiotensin System and the Development of Doc - Salt Hypertension

UNLABELLED The effect of captopril, given in the drinking fluid, on the development of DOC-salt hypertension was analyzed. Although captopril did not prevent an increase in blood pressure (BP) elicited by DOC-salt, captopril did diminish BP in both DOC-salt and control animals. From the first week of treatment DOC-salt rats increased their fluid intake (FI). At the end of the experiment, captopril reduced this increment (655% to 357%). At the same time plasma angiotensinogen was diminished (-35%; p less than 0.001) and cerebrospinal fluid (CSF) substrate concentration increased (+33%; p less than 0.02) in DOC-salt rats, captopril did not modify these changes. In control rats captopril did not alter FI, depleted plasma angiotensinogen, (-73%; p less than 0.001), did not change the central prohormone and increased plasma renin activity (PRA) (+260%; p less than 0.001). IN CONCLUSION CSF angiotensinogen concentration changes as previously found in CNS while a clear dissociation between plasma and CSF angiotensinogen was found in DOC-salt rats. In these animals the hypertension was not clearly affected by captopril treatment. However the effect of the converting enzyme inhibitor suggests that the central renin-angiotensin system could participate in the increase in FI.

The role of extracellular sodium on heart muscle energetics

AbstractA study has been made of changing external sodium concentration [Na]e, over the range 75 to 200 mmol · l−1, on contractile parameters and heat production in isolated, arterially perfused, interventricular rabbit septa.-The observed changes in maximum rate of contraction with [Na]e, either in the presence of a constant external Ca concentration [Ca]e or in the presence of a constant [Na]e2/[Ca]e ratio, paralleled those observed for tension development (T). On the other hand the maximal rate of relaxation

Physiologic studies in mitral stenosis

\left( { - \dot T_{\max } } \right)