摘要:

1. Monkey renin and human renin, but not hog, dog, or rabbit renins, were pressor in the monkey. Monkey renin was neutralized by antirenin to human renin, but not by antirenin to hog renin or antirenin to dog renin.2. Experimental renal hypertension developed consistently in the monkey after unilateral 3:1 renal artery constriction and became more marked after contralateral constriction or nephrectomy. Hypertension usually persisted when the second kidney was left untouched.3. Chronic experimental renal hypertension in the monkey was treated with partial success by crude human renin. Semipurified hog renin was not therapeutically effective.4. Chronic experimental renal hypertension was treated successfully by passive administration of dog serum containing antirenin to human renin, but not by dog serum containing antirenin to hog renin or dog serum without antirenin.5. Prophylaxis of experimental renal hypertension with crude human renin was partially successful in preliminary experiments.6. Attempts to alter the antigenicity of hog renin through chemical treatment so that the antibody to it would neutralize human renin were not successful. Antihypertensive effects were not observed during treatment or prophylaxis experiments with chemically treated semipurified hog renin.7. The interfering effects of renal medulla seen in the treatment of renal hypertension in dogs with hog renin were not observed in monkeys treated with human renin.8. During each individual experiment involving treatment of the renal hypertensive monkey with human renin, correlation was observed between the extent of the antihypertensive response and the antirenin titer to human renin. On the other hand, correlation was not apparent when the antihypertensive response and the maximum antirenin titers of different experiments were compared. However, rough correlation between antihypertensive responses and maximum antirenin titers was observed in passive administration experiments with antirenin to human renin.9. Passive administration of dog serum containing antirenin to human renin to renal hypertensive monkeys was followed by antihypertensive responses which were substantially more marked than in monkeys in which comparable antirenin titers were produced by daily injections of human renin. Passive administration of normal dog serum or dog serum containing antirenin to hog renin was not followed by decreases in blood pressure during initial experiments with dog serum. Sensitization to dog serum was a complicating feature of passive administration experiments after the initial experiment.10. With both active and passive treatment, the minimum titers of antirenin to human renin required for minimal antihypertensive responses in the monkey were lower than the minimum effective titers of antirenin to hog renin observed previously in dogs.11. The chief postoperative complication after renal artery constriction in the monkey was congestive heart failure. Malignant hypertension with necrotizing arteriolar lesions occurred infrequently. Atherosclerosis and cardiac hypertrophy were common findings after a year or more of hypertension. Arteriolar lesions were absent or minimal. Significant nephrotoxic effects did not appear to result from daily injections of crude human renin or from passive administration of dog serum containing antirenin to human renin.12. These results support the hypothesis that renin (or a closely related protein) plays a role in the pathogenesis of primate experimental renal hypertension.13. Passive administration experiments with antirenin to human renin to determine the possible role of renin in the pathogenesis of essential hypertension are a practical possibility.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

The release of norepinephrine from the heart of anesthetized open-chest dogs has been determined both after the intravenous administration of guanethidine (15 mg/kg) and after reserpine (3 mg/kg) by measuring the plasma norepinephrine concentration with the fluorometric method (THI) in bloods obtained simultaneously from the coronary sinus and femoral artery. In four dogs following the administration of guanethidine, norepinephrine release into the coronary sinus blood occurred and persisted for two to three hours. This release of norepinephrine was accompanied by and adrenergic response of similar duration. The norepinephrine content of atrial appendage was reduced by 24% of control at four hours in these dogs and to extremely low levels in three other dogs 24 hours after guanethidine administration. Thus, the reduction of the tissue content of norepinephrine continued after measurable release of norepinephrine into the coronary sinus blood had ceased.In four dogs following reserpine administration the adrenergic response was consistently smaller, and detectable release of norepinephrine into the coronary sinus blood was found transiently only in one dog. However, the norepinephrine content of atrial appendage was reduced by an average of 65% of control values at four hours. These findings suggest a difference in the mechanism of norepinephrine depletion in the period immediately after administration of guanethidine and reserpine.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

The heart rate response to cardioaccelerator nerve stimulation and the corresponding levels of myocardial norepinephrine content were determined and correlated in dogs at various time intervals following the intravenous injection of either 3 mg/kg reserpine, or 10 mg/kg guanethidine. Guanethidine produced complete blockade of the cardiac accelerator response before producing measurable myocardial depletion of norepinephrine. In contrast, reserpine reduced the positive chronotropic response to cardioaccelerator nerve stimulation only after myocardial norepinephrine levels have been reduced to approximately 0.3 μg/g. An infusion of norepinephrine did not restore the heart rate response to cardioaccelerator nerve stimulation in either the reserpine or guanethidine treated dogs. These data suggest that the interference with adrenergic transmission produced by guanethidine is independent of changes in the level of stored adrenergic transmitter. The reserpine-induced blockade of adrenergic transmission may ultimately be dependent upon the mission may ultimately be dependent upon the depletion of adrenergic transmitter, but almost complete depletion of stored adrenergic transmitter must occur before reserpine-induced adrenergic blockade occurs.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

In dogs studied without thoracotomy the detection of immediately appearing indicator in the left ventricle following its injection approximately 1 cm downstream from the aortic valve can be used as a reliable index of the presence or absence of aortic regurgitation.With this type of injection and under the conditions of these experiments, the ratio of the area encompassed by the immediately appearing portion of the dilution curve recorded from the left ventricle to the area encompassed by the primary portion of the curve recorded at the femoral artery bears a close positive correlation (correlation coefficient: 0.9) to the severity of aortic regurgitation as estimated by back perfusion of the valve at necropsy.Within limitations, the position of the tip of the sampling catheter in the left ventricle in dogs with aortic regurgitation is not an important determinant of the amount of immediately appearing indicator detected in this chamber. Furthermore, although the amount of indicator detected in the left ventricle following injections of very short duration is time-dependent, if the duration of the injection is extended to cover the full systolic or diastolic phase of one heartbeat or continues over one or more heartbeats, the exact timing of this injection in relation to the cardiac cycle is not an important determinant of this variable.It is concluded that under these conditions the positive correlation established between the amount of immediately appearing dye detected in the left ventricle (expressed as the regurgitant fraction) and the severity of aortic regurgitation determined by back perfusion at necropsy can be used as a valid means of estimating the severity of aoritic regurgitation in dogs.The applicability of this indicator-dilution method to the study of clinical aortic reguragitation merits further study.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

The experimental production of arteriosclerosis and atherosclerosis by RES blocking agents such as colloidal carbon and thorium dioxide has implicated the RES as a factor in the etiology of these diseases. Holtzman strain male rats each received a single intravenous injection of colloidal carbon (5 mg/100 g animal body wt). Three days later the injected animals were united by parabiosis to non-injected animals of the same sex, weight and genetic strain.Carbon granules were found in the RES of injected rats, but few or no granules were found in Kupffer cells of their non-injected parabiotic partners. Coronary arteries of both injected and non-injected animals showed thickening and fragmentation of the internal elastic membrane after two months. After four to six months the lesions included degenerative changes of muscle cells just external to the internal elastic membrane and thickening of the intima. Hyperplasia of the thyroid was found in both parabionts.Addition of 1% cholesterol-5% fat to the diet caused deposition of lipid in endothelial cells and intimal macrophages of the damaged arteries of both parabionts. Distribution of lipid within the hepatic parenchymal cells was also altered in the experimental animals but not in controls.It is suggested that uptake of particulate matter by cells of the RES causes them to release a substance capable of producing arterial lesions.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

Guanethidine was administered in a single intravenous infusion to supine hypertensive and normotensive subjects. Hemodynamic changes during the transient pressor phase were consistent with catechol amine effect. The later hypotensive effect occurred only in the hypertensive subjects and was usually associated with a slight decrease in cardiac output in patients without cardiac decompensation and a slight increase in output in those with congestive heart failure. Total peripheral resistance decreased although there was an increase in splanchnic vascular resistance and a decrease in the percentage of the cardiac output perfusing the hepatic-portal bed.Tests of sympathetic nervous system activity revealed that, although the Valsalva “overshoot” usually was blocked, complete inhibition of digital vasoconstrictor reflexes did not always occur and vascular responsiveness to tyramine and ephedrine was not diminished up to six hours following intravenous guanethidine. Tyramine responses were also demonstrated in a group of patients on effective long-term oral therapy with guanethidine.These studies suggest that guanethidine has unique hemodynamic effects not necessarily shared by ganglionic blocking agents, bretylium tosylate, or reserpine. Catechol amine depletion probably is not important in the mechanism of the antihypertensive and sympathetic inhibitory actions in man, and the possibility of an additional non-adrenergic effect is considered.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

The velocity of the transmission of the second heart sound in the thoracic aorta of dogs was measured. The average velocity was found to be 5.7 meters per second. The figure agrees well with the published figures for the pulse wave velocity in the thoracic aorta of dogs.It was shown in humans that the velocity with which the second heart sound is conducted along the carotid artery does not change appreciably with frequency between 25 and 100 cycles per second. The average increase in velocity of 2.7% per half octave increase in frequency is, with 30% probability, due to random errors.The fraction of the energy of a murmur transmitted in the form of a transverse vibration along the abdominal aorta of dogs was estimated from recordings made before and after the transverse motion of the arterial wall was impeded with a clamp. Most of the energy of the murmur was found to be transmitted in the form of a transverse vibration in the aortic wall.It was concluded that most of the energy of cardiovascular sound in arteries is transmitted in a mode which is exactly analogous to the transmission of the pulse wave.Some puzzling features of intravascular sound conduction, such as the apparent transmission of murmurs mainly in the direction of flow, could be explained on this basis.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

The validity of cardiac output values from injections of indicator into a peripheral vein was tested. Dye dilution curves resulting from injections of Coomassie Blue dye alternately from peripheral and central sites were obtained in 20 subjects. Peripheral injections in which the dye was not flushed into the circulaton were in a large percentage of cases unreadable. In those which could be read the area under the curve was larger and the cardiac output on the average 8.5% lower than the values obtained from paired flushed injections. Curves from flushed peripheral injections had larger time components and lower concentration of indicator than those from paired central injections. There was no systematic difference in the cardiac output values derived from the two sites. In man, contamination of the primary curve by recirculation of dye does not seem to cause significant error when the indicator is flushed into the venous system in the manner described.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

摘要:

The subepicardial: subsendocardial ratio of Rb86contents was measured and used as an index of the distribution of coronary blood flow to the more superficial and deeper layers of the canine myocardium. In the normally beating heart, the level of intraventricular pressure did not exert any detectable influence upon this ratio of Rb86contents. In the fibrillating heart, or in an ischemic (and presumably non-beating) region of the beating heart, on the other hand, this ratio increased as intraventricular pressure was progressively raised. It is concluded, therefore, that the intraventricular pressure exerts a significant influence upon the distribution of blood flow to the deeper and more superficial layers of myocardium only in regions which are not beating normally.

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:1963

数据来源: OVID