ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

Following experimental myocardial infarction in the dog elevations of serum levels of glutamic-oxaloacetic transaminase (SGO-T), glutamic-pyruvic transaminase (SGP-T) and lactic dehydrogenase (SLD) were consistently noted in decreasing order. Evidence is presented that leakage into the serum from the damaged myocardium plays an important role in these elevations. This concept is supported by analyses of original tissue to blood enzyme concentration gradients, activities of homogenates of infarcts of varying ages, simultaneous measurements of coronary sinus and peripheral venous blood following infarction and contrasting results in man and the dog following infarction.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

The mechanism of atrioventricular delay has been studied in isolated rabbit hearts. Multiple intracellular microelectrodes have been employed to obtain simultaneous records from single fibers of atrium, A-V node and His bundle. An appreciable delay in the transmission of excitation has been found only in the atrial portion of the A-V node. Action potentials recorded from single fibers in this area show a low resting potential, slow diastolic depolarization, slow upstroke and low amplitude. These action potentials frequently show one or more notches or steps on the rising phase. Action potentials recorded from fibers of the His bundle are similar in shape and amplitude to those of peripheral Purkinje fibers. Records obtained at several sites between the atrial portion of the node and the His bundle show a gradual transition in action potential shape. The mechanism of slow transmission across the A-V node is discussed in relation to the electrical activity of fibers at the atrial end of this structure.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

The action of acetylcholine on atrioventricular nodal fibers has been studied with the aid of intracellular microelectrodes. It has been found that during total atrioventricular dissociation no block of conduction occurs at the junction between the A-V node and the bundle of His or within fibers of the atrium. Failure of impulse transmission occurs in fibers in the atrial margin of the A-V node. The application of acetylcholine produces characteristic changes in the action potentials of fibers in the atrial margin of the A-V node: depolarization becomes slow, amplitude falls and notching and slurring appear in the upstrokes. These observations support the concept that transmission of excitation through the A-V node is decremental and that the excitatory process in nodal fibers consists of more than one excitatory event.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

To determine whether myocardial uptake of Rb86can be used as a useful index of coronary plasma flow, the extraction of Rb86from arterial plasma during one passage through the myocardium of dogs was measured at varying rates of flow. At rates of flow which are encountered in man, changes in the rates of flow and uptake of isotope by the myocardium paralleled each other closely. Rb86uptake is a useful index of coronary blood flow in dogs.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

Four dogs and one patient with uncomplicated atelectasis of an entire lung were studied. Arterial oxygen saturations were nearly normal, indicating diminished flow to the atelectatic lung. Angiography confirmed this finding. Vinyl plastic injections showed no evidence of increased bronchial collateral circulation and pathological examination of the atelectatic lung did not demonstrate any bronchiectasis.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

Immature rabbits were subjected to an acute stress period in a modified Noble-Collip drum, alone and in conjunction with an intravenous injection ofE. coliendotoxin. The lethal effects and incidence and severity of the morphologic changes were appreciably greater in the animals given endotoxin in association with stress than in those subjected to rotation alone.The similarity of these lesions to those produced by two properly spaced injections of endotoxin is discussed. The results of the study support the hypothesis that adrenal gland hormones participate in the effects produced by endotoxin.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

Rat colon strips respond to an acute reduction of sodium concentration in the medium (Nao) by an immediate increase in tension, followed by relaxation to the basal tension as the tissue equilibrates. Following equilibration in low Naothe responsiveness to drug-induced contraction is increased, while in high Naoit is decreased. A contraction cycle, variously induced, can be aborted by the acute addition of sodium to the medium. The applicability of these findings to vascular smooth muscle in the whole animal can be demonstrated by appropriate acute sodium infusions. The effects in all cases can be referred to sodium, although modified by the anionic component of the salts used. The results are considered to support the view that smooth muscle tension is governed in part by the concentration gradient Nao/Naiand the theoretic implication of this for chronic hypertensive and hypotensive states is developed.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

Potentials recorded at various sites in the atrioventricular (A-V) conduction system indicate that conduction is continuously electrical in nature and involves no synapse-like (i.e., chemical) conduction. The region between atrium and atrioventricular node has the slowest conduction velocity (.05 M./sec.) and lowest safety factor. Conduction through the A-V node is at about .12 M./sec. Results demonstrate shapes of potentials recorded extracellularly at various sites within the A-V node, first degree and complete block during rapid atrial stimulation, and echo-like phenomena.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID

摘要:

Evidence is presented that reflex systemic vasodilatation occurs after stretching dog's lungs by either mechanical traction or positive pressure ventilation under conditions of separate pulmonary and systemic perfusion. This reflex is mediated by the vagus.

ISSN:0009-7330    

出版商:OVID    

年代:1959

数据来源: OVID