摘要:

Data have been presented which indicate that the liquid scintillation spectrometer provides a convenient and accurate method for the assay of tritium in body fluids. By means of arterial disappearance curves and comparative measurements of concentrations in plasma, transudates, and cerebrospinal fluid from 1 to 6 hours after simultaneous injection, the distribution rates of tritiated water were compared to those of deuterium oxide. No significant difference was found in the behavior of these tracers under the conditions of this study. It is concluded, therefore, that THO and D2O are equally reliable for studies on the kinetics of water distribution and for the measurement of total body water.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Rapid injection of 40 ml. of 5 per cent saline into the femoral or brachial arteries of 24 dogs resulted in an average elevation of arterial blood pressure of +42/+20 mm. Hg, an increase in the heart rate of +20 beats/min., and an acceleration of the respiratory rate of +140 per cent. The response began 6 to 10 seconds after the onset of injection and lasted for 5 to 30 minutes. It occurred with the injection of hypertonic solution of saline, dextrose, and urea. The magnitude of the response was related to the degree of hypertonicity. Responses could be provoked by 10 ml. of 1.25 per cent saline. Rapid intra-arterial injection of isotonic saline, dextrose, and urea solutions, and of whole blood in volumes up to 80 ml. had no circulatory effect. Rapid injection of distilled water, 0.225 per cent and 0.45 per cent saline into the femoral or brachial arteries resulted in a slight degree of hypotension and a rise in the respiratory rate. The appearance of circulating catechol amines following the response to intra-arterial injection of hypertonic solutions was suggested by the demonstration of hypotensive response to intravenous injection of phentolamine. These responses to injection of hypertonic and hypotonic solutions in the femoral artery were abolished by section of the sciatic nerve in animals with an ipsilateral partially-transected hind limb, a preparation which left intact only the femoral artery, femoral vein, and femur. Sciatic section in the intact limb reduced but did not abolish the response. Removal of the sympathetic chain from the eleventh thoracic through the third lumbar ganglia had no apparent effect. It is concluded that the response to femoral aud brachial intra-arterial injection of hypertonic and hypotonic solutions is initiated by peripherally located “osmoreceptors” in the distribution of these arteries and is mediated via a reflex whose afferent fibers travel in the peripheral somatic nerves and enter the spinal cord without passing through the sympathetic chain. The efferent are is the sympathetic nervous system.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Dogs were bled to a mean arterial pressure of 35 mm. Hg and maintained at this level for 4 to 5 hours, or until 40 per cent of their maximum bleeding volume was taken back spontaneously. When the superior mesenteric artery was autoperfused at normal rates with arterial blood, only 2 of 22 animals survived. On the other hand, when a donor animal was included in the perfusion system, a significantly higher (P=0.03) fraction survived (5 out of 14). If the removed blood was not reinfused as soon as 40 per cent of the maximum bleeding volume was taken back but the hypertensive period was maintained for a full 5 hours, then only 1 dog out of 9 survived as long as 35 hours, despite the fact that all 9 dogs in this group were given additional transfusions equal to the “take-up” volume.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Arterial hypertension was produced in 66 rats by means of constricting latex capsules about the kidneys, by the intramuscular implantation of desoxycorticosterone pellets, and by the subcutaneous injection of desoxycorticosterone. The most satisfactory method was the intramuscular implantation of desoxycorticosterone pellets. Myocardial hypertrophy was produced in 43 rats.Biochemical analysis of the ventricles of 80 control and 45 hypertrophied rats were performed for creatine phosphate, adenosine triphosphate, and free inorganic phosphate. Cardiac hypertrophy in rats was accompanied by a statistically significant decrease in the ventricular concentration of creatine phosphate, while levels of adenosine triphosphate and free inorganic phosphate were not significantly altered.It is suggested that congestive heart failure in hypertrophied hearts is related to a defect in the utilization of phosphate-bond energy by the hypertrophied myocardial fiber.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Narrowing of the internal and external carotid arteries by a clamp does not lead to hypertension if the carotid sinus nerves remain intact. Subsequent disruption of the carotid sinus nerves results in hypertension. It is concluded that the cause of the chronic hypertension in dogs with constriction of the carotid sinus is not due to altered cerebral hemodynamics, but rather to disruption of the carotid sinus nerves.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Constriction of 1 renal artery in combination with disruption of the carotid sinus nerves resulted in moderate chronic hypertension in dogs. Hypertension persisted at the same level in some of the animals after removal of the kidney 1 year later, while in others blood pressure decreased somewhat though not to the prehypertensive control level. Narrowing of 1 renal artery without carotid nerve disruption did not lead to significant chronic hypertension. Disruption of the carotid sinus nerves alone, on the other hand, produced mild to moderate hypertension. Constriction of 1 renal artery, if performed several months after carotid nerve disruption, further increased the blood pressure in these animals. Tests of the carotid sinus nerves function by the occlusion reflex of the common carotids indicated a return of function several months after disruption in animals in which the carotid sinus nerves were only crushed. Hypertension persisted in these animals despite the return of the carotid sinus function. Tetraethylammonium choride given intravenously to combined carotid sinus-unilateral renal hypertensive dogs resulted in blood pressure decrease similar to that produced in normal animals. Glomerular filtration rate and renal plasma flow decreased, and filtration fraction increased in 3 dogs following production of the combined type of hypertension.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Chronic impairment of cardiac lymph flow was successfully accomplished in 22 dogs after preliminary anatomic studies revealed a feasible surgical technic. The anatomic and surgical details are presented. Gross and microscopic studies were possible in 19 of the operated animals, 3 of which died spontaneously, and 16 of which were sacrificed at varying time intervals between 2 and 16 weeks after surgery. Two of the 19 dogs were completely normal on gross and histologic examination. Abnormalities found in the remaining 17 animals included left and right ventricular subendocardial hemorrhages, increased elastic and fibrous tissue in the left ventricular endocardium, and opacification of the mitral valve leaflets.It is concluded that chronic impairment of cardiac lymph drainage is productive of significant endomyocardial pathology. These observations are considered to be important as possible etiologic mechanisms in endomyocardial fibrosis and endocardial fibroelastosis. The cardiac lymphatics merit continued intensive investigation, inasmuch as they surely have an important role in cardiac physiology and pathology. Their importance may encompass a far broader area than suggested above. They may be related to the so-called nutritional cardiopathies. The fibroplastic effects of serotonin might occur through an effect on the cardiac lymphatics. Impairment of heart lymph flow may be important in endocarditis and myocarditis of certain types, for it is known that chronic lymphatic obstruction predisposes to recurrent inflammation and infection in the affected parts.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Very small doses (0.1 to 2.0 μg./Kg.) of epinephrine injected in 1 minute into dogs anesthetized with 20 per cent cyclopropane cause a coupled rhythm which is usually bigeminal and characterized by an exceptionally constant interval between the coupled beats. Phenyiephvine also causes this arrhythmia, methoxamine does so rarely, but isoproterenol does not. An elevation in systolic pressure and possibly a tachycardia are required for the appearance of bigeminy. However, this arrhythmia can be elicited consistently by these factors only in the presence of a sympathomimetic amine with cardiac stimulant actions. A focus of automaticity has been ruled out in the genesis of the abnormal ventricular beat by demonstrating the constancy of the coupling interval despite sudden changes in the atrial rate. Dichloroisoproterenol appears to attenuate the induction of bigeminy by epinephrine to a considerably lesser extent than the major arrhythmias expected on injection of large doses of this sympathomimetic.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Pressure relationships in the left ventricle of the dog were studied under conditions in which left ventricular inflow was controlled by means of an artificial circuit. Hypothermia was used to slow the dynamics of the heart beat. When all inflow to the left ventricle was suddenly stopped, the succeeding beats showed negative diastolic pressures. The greatest drop in pressure occurred early in diastole; in most instances, end-diastolic pressures remained negative. Early diastolic pressures before occlusion average +2.6 mm. Hg; early diastolic pressures after occlusion of inflow averaged −4.7 mm. Hg. A physical model was proposed which could explain the occurrence and decay of the observed subatmospheric pressure. These experiments indicate that diastolic suction can be a factor that accomplishes ventricular filling during diastole in a heart following systolic discharge against a wide range of aortic pressures.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The beaching of a 40-ton fia-back whale on a Provincetown shore provided a fortuitous opportunity for taking the first cardiograms of the largest mammal. A representative 15-lead cardiogram is shown. This does not differ materially from other large mammals, except that the time scale of events is extremely prolonged. Abnormal foci of ventricular beats and compensatory pauses are illustrated.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID