ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

The increase in oxygen consumption produced in man by salieylate administration is not associated with a rise in pulse rate or an increase in responsiveness to infusions of epinephrine or norepinephrine. It is suggested that the effects of thyroid hormone on the cardiovascular system are more dependent on the concentration of circulating thyroid hormone per se than on the concomitant increase in tissue oxygen consumption.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Evidence has accumulated suggesting acetylcholine may he involved in initiation of the heart heat. Acetylcholine and electrolyte metabolism in the various chambers of the heart have been studied. The area of highest intrinsic rhythm (sinus) contained greater amounts of acetylcholine equivalents, true cholinesterase, choline acetylase and sodium; all of these decreasing in amount in areas of lower intrinsie rhythm. It is concluded that intrinsic rhythm may he directly correlated with overall acetylcholine metabolism and sodium content and inversely related to overall energy metabolism and potassium concentration.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Femoral pulsatile pressure and flow in anesthetized dogs were measured as time series. The computed cross products of pressure and flow were also expressed as time series. The statistical variance (ó2) of each of these was analyzed into a frequency spectrum. The spectral magnitudes at each frequency were used to compute the pressure-flow coherence, impedance magnitude and phase angle as a function of frequency. The high coherency between pressure and flow at most frequencies indicated that a linear deterministic model may suffice to express the opposition to flow pulsations. The impedance variation with frequency indicated that the model may be frequency dependent. Computed autocorrelation and cross correlation functions measured the statistical nature of the observed time series.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Myocardial infarcts were produced in rats by ligating the anterior descending branch of the left coronary artery. After one hour, changes in the ultrastructure of myofibers in the infarcts were readily demonstrated by electron microscopy. These changes became progressively severe with time, and consisted primarily of swelling of mitochrondria and sarcoplasmic reticulum followed by increased lipid droplets and myolysis. Autolysis Atolysis of myocardium was also studied and the changes found to be similar to those of myocardial infarcts, but more uniform and slightly delayed in development. Perhaps the early ultrastructrural changes are related to hyperosmolarity of mitochondria and sarcoplasmic reticulum, especially after cell death. It is hoped that definition of ischemic ultrastructural change will be useful in defining electron microscopic lesions in other forms of myocardial damage.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

This Paper is concerned with the pattern of cardiorespiratory and renal changes produced by opening a systemic arteriovenous fistula. Flow through bilateral femoral arteriovenous fistulas averaged approximately 53 per cent of the control cardiac output. The rise in cardiac output elicited by the shunt averaged 51 per cent of the shunt flow PAH clearances decreased 23 per cent in animals anesthetized with sodium pentobarbital, and 46 per cent in animals premedicated with morphine sulfate prior to administration of sodium pentobarbital. The per cent reduction in renal blood flow did not differ significantly from the per cent reduction in flow through the extrarenal systemic capillary beds.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Spontaneous ventricular electrical potentials of whole mammalian hearts subjected to complete ischemia were investigated by means of the intracellular microelectrode. Spontaneous membrane action potentials persist for 20 min, following the onset of anoxia. Early, the duration of the action potential shortens, followed by a progressive fall in the amplitude of the spike. The resting potential shows a diminution to 65 per cent of the control value. The relationship of these effects to change in membrane ionic transports and metabolic processes are discussed.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

As part of a larger study on the development of a collateral circulation, observations were made on the ear of the albino mouse. One or more arteries or veins were transected and the development of the resulting collateral circulation was followed.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Both pressure and oxygen content of blood in the left pulmonary artery distal to an inflated balloon simulate that observed in the wedged cardiac catheter position. Clamping the ipsilateral pulmonary veins after inflation of the left pulmonary artery balloon, in this or in the reverse order, produces a rise in pressure distal to the balloon that exceeds the resting left pulmonary artery pressure. No corresponding increase in oxygen content of blood sampled distal to the inflated balloon, compared with that in the unoccluded pulmonary artery, could be demonstrated. This contrasts with the flow of arterialised blood that had been sampled after some months of permanent left pulmonary artery occlusion from the same position. The pressures both proximal and distal to the site of permanent occlusion are approximately the same.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID

摘要:

Various purine and pyrimidine ribosides, with the exception of adenosine, have been found to exhibit a positive inotropic effect on an isolated strip of frog ventricle. In a preparation responding maximally to one compound, the addition of a second compound led to a further increase in tension. This relationship was found to apply among the members of a given group (purine or pyrimidine) paired in various combinations, as well as in experiments pairing purine against pyrimidine riboside. Adenosine showed brief stimulation followed by depression, pure depression or no effect.

ISSN:0009-7330    

出版商:OVID    

年代:1958

数据来源: OVID