ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

In 15 anesthetized dogs, constriction of the lumen of the pulmonary artery by less than 50 per cent produced no significant change in intraventricular pressure or cardiac output. Additional constriction caused a progressive increase of the right ventricular pressure; up to a pressure of 62.3±3./min. Hg, there was no change in cardiac output. With higher right ventricular systolic pressure there was a reduction in cardiac output, gradual decrease in systolic pressure but increase in diastolic pressure of both ventricles, and ultimately dilatation of the heart and ventricular arrest or fibrillation.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Sera from 10 patients with essential hypercholesterolemia on ad libitum diet have been analyzed for their content of polyunsaturated fatty acids in the cholesterol esters and the results compared with a matched group of normal subjects. Three cases were analyzed after corn oil substitution for other fats in the diet, and 2 of them were analyzed after addition of pyridoxine to the corn oil regimen. One patient was followed 18 months, and during that time he received a large dosage of corn oil.Patients with essential hypercholesterolemia had an absolute increase in the amount, but generally a lower percentage content of dienes in their cholesterol esters than normals. After the change to corn oil, the content of polyunsaturated fatty acids increased to levels sometimes considerably above those in the normal subjects, although the total serum cholesterol in one of these cases was by no means normalized. The addition of 100 mg. of pyridoxine to the corn oil regimen did not produce any further decrease in the serum cholesterol level and did not produce any changes in the fatty acid fractions.The absolute increase in the amount of polyunsaturated fatty acids in the cholesterol esters in essential hypercholesterolemia, particularly after an extremely high intake of unsaturated fat, speaks against factors causing an inhibition in esterification with polyenes as being of central importance.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Acute elevation of left atrial pressure could be precisely controlled at any desired level up to a mean of 60 mm. Hg in dogs with an intact thorax. The following observations were made in a series of 15 dogs. Right lymphatic duct flow did not increase at acutely elevated left atrial mean pressure below 25 mm. Hg, whereas flow increased 3- to 4-fold at mean pressure above 25 mm. Hg. The total amount of lymph at maximum flow, however, was only 0.3 ml./min. Lymph flow remained elevated for as long as 1 hour after left atrial pressure was restored to normal. Elevation of left atrial pressure did not affect lymph flow in the thoracic duct. Pulmonary edema did not occur readily at left atrial mean pressure elevated only slightly above plasma oncotic pressure. The production of pulmonary edema was observed only after a considerable elevation of left atrial pressure above plasma oncotic pressure was maintained for a period of one half hour or more in an otherwise normal dog. The hematocrit increased significantly after a 10-minute period of high left atrial pressure. Pulmonary vascular resistance decreased sharply as left atrial mean pressure was raised from 0 to 15 mm. Hg. The resistance gradually rose as left atrial pressure was raised to between 15 and 30 mm. Hg. Pulmonary arterial pressure uniformly rose and cardiac output uniformly declined with increasing left atrial pressure.Chronic elevation of left atrial pressure was achieved in 15 dogs. Left atrial mean pressure varied from 10 to 23 mm. Hg. These dogs were followed up to 10 months and the following observations were made. Right lymphatic duct flow did not increase at chronically elevated left atrial mean pressure below 25 mm. Hg. Flow was not studied at higher pressures since we were unable to sustain left atrial mean pressure above 25 mm. Hg in any dog in our chronic group. The animals that were brought to left atrial mean pressure between 30 and 40 mm. Hg and in whom these high levels were presumably maintained were found dead in their cages with pulmonary edema 1 to 2 days after tightening the snare. Many of the usual functional and structural changes often found in lungs of patients with mitral stenosis, except for hemosiderosis, were not observed in our experimental animals although the extent of the supravalvular stenosis produced was marked. Pulmonary arterial pressure rose slightly and cardiac output declined slightly. No change was noted in pulmonary vascular resistance. Ascites and other signs of right sided failure were not encountered.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Reports in the literature to the contrary, hypertensive cardiovascular disease proved to be readily induced by desoxycorticosterone in hypophysectomized rats sensitized to steroid action by partial nephreetomy and high NaCl intake. In the absence of the pituitary, however, hypertension was somewhat slower in onset and progress. Although hypophysectomized animals were able to develop hypertension as severely as did intact animals, they were not, as judged by their better survival and less evident cardiorenal vascular lesions, as severely injured thereby.Contrasted with their exuberant development in hypertensive intact animals, renal lesions in hypertensive hypophysectomized animals were rare. Necrotizing arteritis in the heart was seen in about half of the hypox animals, and periarteritis nodosa of pancreatic and mesenteric arteries was more widespread and severe than in similarly treated intact animals which had, however, died earlier.Steroid treated animals bearing pituitary autotransplants beneath the renal capsule, developed more severe and widespread cardio-renal lesions than did similarly treated hypophysectomized animals, but incidence and severity of periarteritis nodosa in splanchnic arteries was about the same in each.The ingestion of sodium chloride caused “salt hypertension” in some of the pituitary-bearing controls, but not in either hypophysectomized or autotransplant-bearing controls.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The frequency analysis of the electrocardiogram reveals that contributions by frequencies of 100 cycles, or higher, per second are less than 10 per cent of the amplitude of the fundamental of the QRS comples, and it thus appears that transistor-driven amplifier-pen recorders presently available are adequate to record all the information contained in the electrocardiogram, if the standard paper speed is doubled, or quadrupled.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Experiments performed in anesthetized dogs have shown that occlusion of the coeliac and mesenteric arteries may determine minor increases of systemic blood pressure, obviously of hemodynamic nature and not induced by baroreceptive vasomotor reflexes. Increase of pressure into the mesenteric arterial circulation does not decrease the systemic blood pressure. The aortic and carotid sinus baroreceptors are the major means of the reflex blood pressure homeostasis. Evidence for the existence of specific chemoreceptors in the abdominal vascular area could not be obtained.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The early stages of the development of collateral circulation to the lung following experimental ligation of the pulmonary artery were studied in adult rats. Five different types of vessels were found to be involved:1. The bronchial arteries enlarge. Quantitative gross and microscopic studies indicated that this is first due to hemodynamic factors leading to dilatation of the vessels. After 5 days, true growth of the vessels occurs, associated with proliferative changes in the vessel wall, including mitoses in endothelial and smooth muscle cells.2. Pre-existing nutrient arteries of the heart muscle coat of the pulmonary veins enlarge by the same processes.3. New vessels form in the granulation tissue at the ligature. They can grow through the thick vessel wall into the lumen of the main pulmonary artery to form a considerable portal of entry for blood into this vessel.4. Vessels form in pleural adhesions and can supply blood to the lung from intercostal arteries.5. New bronchial arteries form in regions where no granulation tissue formation could stimulate their development. The primary anlage consists of a solid cell cord, soon surrounded by an envelope of spindle-shaped cells, representing the anlage of the media. The cell cord differentiates secondarily to an endothelial tube by forming a lumen.The enlarged systemic arteries are directly connected to the lung capillaries by means of multiple small branches, which are also newly formed arteries or arterioles. Arterial bronchopulmouary anastomoses are not as commonly found early in the development of collateral circulation in the rat, as late in this process in dogs. It may be concluded that the enlargement of collateral arteries to the lung following ligation of the pulmonary artery may be initiated by hemodynamic conditions, such as changed pressure gradients. After 5 days, however, other, probably humoral, factors must be responsible for further stimulation of the growth of pre-existing vessels and for the initiation and guidance of new vessel formation.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Levarterenol-induced hypertension may slow, increase or produce no change in the cardiac rate of persons with cardiovascular disease. The degree of cardiac disability at least partly determines the type of response.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID