摘要:

The application of elastomeric theory to the study of the viscoelastic properties of the dog's aorta shows that the same value of the elastomeric parameter β may be used to describe the elastic behavior of aorta strips under both static and dynamic conditions. The variations in the parameter β and the damping fraction γ with the strip's location may be distinguished only for the extremes of the central arterial axis because of the wide variability of mechanical properties among dogs. The viscoelastic properties apparently do not correlate with the measured geometric properties of the unstressed aortic strip.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The histochemical nature and the biologic characteristics of the specific cytoplasmic granulations of the juxtaglomerular (J-G) cells of the kidney have been reinvestigated. In the rat, it appears that these cells are mesenchymal in origin and capable of reacting as part of the reticuloendothelial system when exposed to the action of long-chain polymers like dextran or ovomucoid.The substance contained in the granules is probably constituted by a mixture of polysaccharide sulfate esters and lipoids, accounting for their staining properties with metachromatic dyes. Hyaluronic acid is not responsible for the latter reaction.The J-G granules respond in a manner strikingly similar to that of mast-cell granules after treatment with dextran or ovomucoid. The attempt to quantitate the amount of histamine liberated by degranulation of J-G cells has been less successful than with degranulated connective tissue mast cells, owing to the low J-G cell/parenchyma ratio in the kidney.The presence of mast-cell-like elements at the vascular pole of the kidney glomerulus is stressed in view of their possible role in the functional activity of the nephron, owing to the fact that degranulation of these cells is capable of releasing anticoagulant and vasoactive substances like heparin, histamine, and serotonin proximal to 1 of the most important circulatory districts of the body.The finding of elements with analogous characteristics in the subintimal layer of arterioles in other organs raises the question as to whether J-G cells play a less specialized role in the kidney than hitherto supposed.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The changes in petechial susceptibility of the vessels of hamster cheek to the moccasin venom test have been compared in shielded and irradiated pouches of the same animal which had received median lethal doses of x-irradiation. There was no statistically significant difference demonstrable between the irradiated and controlled cheek pouches, but both showed a greater hemorrhagic response than was found in the cheek pouches of unirradiated control animals.Similar results were found when the diffusion of intradermally injected Evans blue was used as an indication of x-irradiation damage. The shielded and the exposed areas both showed enhanced permeability to the dye when compared with the unirradiated control animals.These results suggest that some indirect factor or factors are involved in the vascular and permeability changes following exposure to ionizing radiation.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Page 153: Legends for figure 2:Arefers to right lower;Bmiddle lower;Clower left;Dupper right;Eupper center; andFupper left.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Simple plastic constricting devices for producing experimental arterial stenosis may be prepared from formalinized polyvinyl alcohol (surgical ivalon) sponge. Not a single instance of arterial rupture, a common sequel of stenosis produced by rigid devices, was encountered in 56 experiments.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

In 22 dogs, the effect of fibrinolysin therapy of fresh intravascular clots was evaluated by serial angiograms and autopsies. The average time required for dissolution of such clots, when treated by systemic plasmin, was 4 hours and 45 minutes, while the average time necessary for lysis with local fibrinolytic therapy was 2 hours 10 minutes. Treatment of fresh venous and arterial clots did not disclose any significant difference in susceptibility to lysis. In 21 dogs, the effect of age of the clot on the effectiveness of plasmin therapy was studied in clots formed with serum and morrhuate. Clots treated within 4 days of formation were susceptible to dissolution, although clots treated after 3 days did not uniformly undergo complete lysis. The serum-induced clots were more amenable to fibrinolytic therapy than were those formed with morrhuate.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The dissolution of clots formed at normal fibrinogen levels and in hyperfibrinogenemia was studied in 10 dogs receiving a standard course of fibrinolytic treatment. A significantly increased resistance of clots formed at high fibrinogen levels to fibrinolytic therapy was found.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

We have recently reported a dietary method for the production of thrombosis and infarcts in rats and have suggested that part of the mechanism of thrombosis in these animals was interference by the diet with some hematologic factor, possibly fibrinolysis. In the study reported herein, we have developed a method for studying fibrinolysis in rats in vitro, utilizing an electronic device called the Thrombelastograph. Results of this study correlate well with the previously demonstirated thrombogenic properties of 2 of the diets. Rats on a “butter-thiouracil-cholesterol-bile salt” diet (known to produce thrombi and infarcts) have prolonged clotlysis times, as compared with rats on a similar diet (and not thus far associated with thrombi and infarcts) in which corn oil is substituted for butter. Although the in vitro test is performed under highly artificial conditions, they are carefully standardized and the fact that the results correlate well with previously demonstrated thrombogenic properties of the diet would suggest that it has practical value for the study of thrombogenic effects of various diets in experimental animals. It is possible that it will prove to be even more useful in the study of fibrinolysis in man.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

In open-chest dog experiments, 7 different types of cardiac failure were produced. In each type of failure, the effect of veno-arterial pumping and of left ventricular bypass (blood pumped from the left atrium to femoral artery) was investigated. Pressures were recorded in the left ventricle, the left atrium, the right ventricle, and the femoral artery.Veno-arterial pumping reversed failure of the right ventricle. It also was beneficial when overtransfusion had aggravated failure of the right or left ventricles, except in pre-existing aortic insufficiency. Veno-arterial pumping markedly increased decompensation of the left heart in the majority of observations, even though it occasionally reduced pressures in the left atrium and the right ventricle. The experiments suggest the use of veno-arterial pumping or of partial bypass with a heart-lung machine in acute cor pulmonale and in pulmonary congestion caused by abnormalities of the mitral valve where the left ventricle remains compensated. Veno-arterial pumping appears contraindicated in true failure of the left ventricle.Left ventricular bypass always restored compensation in all types of heart failure except cor pumonale. The experiments suggest the clinical use of left ventricular bypass in left heart failure.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Rhythmical changes in small vein pressure were shown to follow the direction of changes in intra-abdominal pressure. Pressure waves in small veins could be diminished considerably during femoral artery occlusion when the venous cannula was directed away from the vena cava. They were only slightly affected when the venous cannula was directed toward the vena cava. Small vein pressure waves were markedly decreased by opening the abdomen and reducing intra-abdominal pressure.It is concluded that intra-abdominal pressure change is a major factor in varying small vein pressure in the hindleg of an anesthetized dog in a supine position.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID