摘要:

Histochemical and chemical studies of the acid mucopolysaccharide content of the aorta were made in rabbits fed cholesterol for up to seven months. Colloidal iron staining suggested an increase in acid mucopolysaccharide content of the aortas with mild atheromatous lesions but not when severe lesions were present. Chemical determination, however, revealed no increase in the concentration of acid mucopolysaccharide in early lesions, but did reveal a significant increase in the more severely atheromatous aortas of rabbits fed cholesterol for 6 months or more.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The indicator-dilution method was used in the dog in an attempt to define the proportion of the “central” blood volume contained in the lung vessels. When injections were made into the pulmonary artery with sampling from the femoral artery only half or even less of the calculated blood volume could be accounted for by the lungs. When a venous injection site was used, the proportion in the lungs was reduced to a third or less. Thus when peripheral sites are used for the inscription of indicator-dilution curves few deductions can be made about either the actual volume or even relative changes in the volume of blood in the lungs.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Since sympathetic stimulation could play an important part in the short term attacks of angina pectoris, the effects of nitroglycerin on the myocardial response to levarterenol were investigated. Levarterenol infusions directly increased the isometric systolic tension (IST) developed by the cardiac muscle. Nitroglycerin had no apparent direct effect on this increase in IST either in the normal heart or in the heart following partial coronary ligation. In experiments in which IST was measured with a lever system adjusted to the end-diastolic length and tension occurring just prior to the contraction, nitroglycerin was found to have an indirect depressant effect on the levarterenol response. This decrease in contractility was shown to be secondary to a decrease in hemodynamic work load elicited by nitroglycerin. It is suggested that the chief effect of nitroglycerin in the relief of angina pectoris is due to this agent's ability to decrease a work load imposed on the myocardium by sympathetic stimulation.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

In open-chest dogs it was found that levarterenol produced primary RS-T segment depression in epicardial surface electrocardiograms together with increases of ventricular muscle contractility. These effects occurred in nonischemic, regionally ischemic, and hypoxic myocardium and were accompanied by rises of polarographic myocardial oxygen and a reddening of coronary venous blood in all but the lowest dosages. The findings are discussed in the light of the pertinent experimental literature.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Electrocardiograms of normal rats and those rendered hypertensive by potassium deficiency have been compared. The unipolar chest leads were found to be useful in the recognition of spurious patterns among normal animals as well as in evaluating the severity of the hypertension. Backward orientation of the spatial QRS vector in the horizontal phane was the single most consistent finding in the hypertensive animals.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The effects of moderate and severe hemorrhage on the cardiac output and its distribution have been studied in the rat. In moderate hemorrhage, cerebral and adrenal blood flow are well maintained through localized vasodilatation while most other organs show increased vascular resistance and diminished blood flow. After severe hemorrhage, despite further changes in territorial resistances, the blood flow is not maintained in any area of the body.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Potential changes attending excitation of the atrioventricular node, the common bundle, the bundle branches, and initial ramifications of the conducting tissue in the subendocardium of the bovine heart beating in situ have been recorded from unipolar exploring electrodes. Correlations between the form of nodal deflection and the location in the node of the electrode tip have been established. From right bundle branch and subendocardial action potentials, data were derived indicating a rate of transmission through the right branch of 2.02 M/sec. Certain observations on the effects of acute injury and severe hypoxia are recorded. The character of nodal deflections attending retrograde excitation is reviewed.In studies on canine hearts beatingin situ, electrograms have been made from the regions in which the atrioventricular node, the common bundle, and bundle branches are believed to lie. Deflections comparable to those recorded in bovine experiments were encountered and, by analogy with those bovine studies, certain morphologic correlations postulated. In general, canine nodal deflections are smaller than their bovine counterparts and lack the variety of form ascribed to potential changes in the several portions of the bovine node. In canine studies, deflections of atrial, atrionodal, and nodal type coexisted in recordings from a single needle electrode suggesting a degree of proximity between the sources of these potential changes not encountered in bovine experiments.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

On the basis of local thermodilution a method for measuring blood flow in a single vessel was elaborated. The measurement was accomplished by a special catheter with an injection orifice and a thermistor. The accuracy of the method was studied both in model and in vivo experiments on dogs (in jugular vein, in carotid and pulmonary artery) and good correlation was found with direct methods.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

It is generally assumed that blood is completely mixed while passing through a ventricular chamber. This assumption underlies use of indicator dilution technics for estimation of ventricular volume. In the left ventricle of the exposed canine heart, complete mixing of blood and injected saline during one cycle was rare, especially if the heart rate was in the normal range. Computations of absolute ventricular volume are subject to error if they are based on the assumption that indicator injected into the ventricular cavity becomes uniformly dispersed throughout the ventricular cavity before the end of diastole.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Administration of a therapeutic dose level of digoxin in the intact dog resulted in an augmentation of the glucose utilization of the myocardium accompanied by a greatly increased rate of glycolytic and oxidative activity. The contribution of glucose to the total metabolism of the heart was increased, and the utilization of noncarbohydrate substrates was decreased. These metabolic changes occurred in the absence of changes in the dynamic functions of the heart, indicating that the metabolic alterations were due to a primary effect of the drug rather than an effect secondary to an altered state of cardiac activity.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID