摘要:

The indicator-dilution method of determining cardiac output and mean transit times can be employed to estimate indirectly the volume of blood in the larger veins in vivo although it is difficult to define precisely the peripheral anatomic boundaries of the volume so measured. In 12 anesthetized dogs the “venous” blood volume obtained by multiplying cardiac output and mean transit time from femoral vein to right atrium averaged 16.6 ml./Kg., or 18 per cent of total blood volume. Rapid intravenous infusion of dextran solution caused no significant change in the blood volume of the large veins, heart or lungs.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Many previous investigators have presented data suggesting that the processes involved in excitation and recovery in heart muscle limit the “vulnerable period” to a relatively small part of the heart cycle in late systole. Evidence presented in this report indicates that there are exceptions to this rule, at least in the intact animal, since under some conditions multiple extrasystoles and ventricular fibrillation can be elicited by single stimuli of short duration and high voltage applied at almost any time in systole or diastole.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

The positive inotropic action of hexamethonium in hypodynamic and freshly prepared papillary muscles of the eat and the hypodynamic heart-lung preparation of the dog has been demonstrated. Within certain limits, there exists a proportionality between the concentration of hexamethonium and the magnitude of the inotropic response. In both preparations results have been obtained which indicate that a state of partial refractoriness to the positive inotropic action of hexamethonium may be produced.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

The renal circulation of the dog was studied by a rheoplethysmographic method capable of simultaneously recording the time courses of volume, rate, and acceleration of inflow, outflow and difference between inflow and outflow of blood. The studies were done first under control conditions and then under conditions of relatively acute circulatory change induced by intravenous injection of norepinephrine and hexamethonium.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Left atrial and left ventricular volumes, regurgitant flows and systolic efficiencies have been calculated for dogs with and without mitral valve insufficiency, using a technic of electric analog simulation of radioisotope dilution data. Amounts of blood between the valve of the pulmonary artery and the left atrium were calculated by use of mean transit time and flow, and compared to those of the analog. It is concluded that the analog technic is practical and will be more useful when data is available on flow patterns in the pulmonary bed.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

This report concerns the phagocytic behavior of the Kupffer cells in the rat during hemorrhagic studies by quantitative technics. The rate of clearance (measured by colloidal carbon) was suppressed by 50 per cent after 3 hours. Efficiency of clearance (measured by uptake of radioisotope labeled albumin and chromium phosphate) was likewise markedly below normal. This factor was not due to reduced blood flow through the liver, as evidenced by measurements made 1 hour after blood replacement. Histologic evidence suggests two possibilities: a localized impairment of Kupffer cell activity in the area about the central veins of the lobule, or an abnormal circulation through preferential pathways restricted to the periphery of the liver lobule.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

The 72 hour chick embryo heart reacts to progressive hypoxia by the appearance of arrhythmias and asystole. In the presence of 4 per cent CO2, complete anoxia is tolerated for a period of 30 min. with carbon dioxide apparently augmenting the buffering capacity of the plasma clot which supports the heart. A gaseous environment of 4 per cent O2/4 per cent CO2/92 per cent N2induced a steady and entirely reversible state of cardiac stress.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

The pressure-flow relationship was studied in isolated denervated intestinal loops of the dog in a range of pressure varying from 0 to 240 mm. Hg. The relationship was curvilinear, convex to the pressure axis. Flow started at a minimal pressure of 16 mm. Hg, then increased more rapidly than pressure up to 240 mm. Hg. Critical closure, passive expansion of vessels with rising intraluminal pressure, and anomalous viscosity of blood appeared to be the important factors influencing vascular resistance and flow in the present studies.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

It has been shown previously that an empty ventricle can suck in a small amount of fluid during diastole, but the question of whether a normal ventricle does so was not answered. In the present experiments it was demonstrated that even a ventricle with a more nearly normal endsystolic residual volume draws blood into its cavity and that this ventricularvis a fronteis augmented by the action of epinephrine.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Isolated canine kidneys were perfused with oil which did not accumulate extravascularly and which prevented renal vasomotor responses. The purely physical effects of changed arterial pressure on renal vascular flow and resistance were studied.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID