摘要:

During a 15-minute period of myocardial ischemia, glycogen concentration fell. This decrease was roughly accounted for by increases in hexosemonophosphate and lactic acid. Fructose 1,6-diphosphate, dihydroxyace-tone-phosphate and pyruvate did not accumulate. The myocardial concentration of adenosinetriphosphate declined. Reperfusion of the ischemie heart with oxygenated blood was accompanied by inconstant changes in myocardial glycogen and by rapid lowering of hexosemonophosphate. The hexosemonophosphate decrease occurred even when the ischemie myocardium was perfused with a deoxygenated buffered salt solution and is attributed in part at least to lactic acid washout. Adeno-sinetriphosphate rose steadily when the heart was perfused with oxygenated blood containing 15 mmoles KCl to prevent cardiac activity. When KCl was not added, fibrillation and irregular contractions occurred within 1 to 2 minutes. In these instances, the rise in adenosinetriphosphate was irregular and inconstant.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Following myocardial infarction, the pseudoviscosity of whole blood and the viscosity of plasma increase significantly. The increase in viscosity is correlated with increase in fibrinogen. Both are correlated with the severity of the infarction. The pseudoviseosity of blood adjusted to a hematocrit of 40 shows fair correlation with the viscosity of plasma.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

A pressor amine (methoxamine) which produces peripheral vasoconstriction, while lacking a significant, direct, positive inotropic effect upon ventricular heart muscle, has been shown to produce hemodynamic effects that are in distinct contrast to those resulting from the injection or infusion ofl-epinephrine andl-norepinephrine in “physiologic” concentrations or of mephentermine sulfate. The latter 3 amines, possessing a positive inotropic action in addition to varying vasoconstrictor effects, decrease right and left atrial mean pressures while increasing femoral and pulmonary arterial pulse and mean pressures, right and left ventricular stroke works and the cardiac index.Methoxamine injection or infusion, in contrast, resulted in linear increases in the calculated total peripheral resistance and left and right atrial mean pressures. There was a simultaneous rise in right and left ventricular stroke works which were maintained until a maximum rise in the mean arterial pressure was reached. The average stroke volume indices were maintained at near control values in both blocked and unblocked animals. The cardiac index of the normal unblocked dogs decreased in proportion to the decrease in heart rate.Following the peak pressor response to methoxamine, a progressive fall in mean femoral arterial pressure occurred resulting from ventricular failure rather than “tachyphylaxis” to the vasoconstrictor activity of methoxamine. This decrease in systemic arterial pressure was accompanied by: (1) a further rise in calculated total peripheral resistance and in right and left atrial mean pressures, and (2) a fall in right and left ventricular stroke work and stroke volume indices and in the cardiac indices.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

1. In the anesthetized dog, end-diastolic, end-systolic and stroke volumes for the left ventricle have been calculated according to the method of Holt from dilution curves recorded at the aortic root. For heart rates of less than 120 beats per minute, the catheterdensitometer systems used gave 90 to 95 per cent of the true concentration in the aortic root at the end of diastole.2. Average volumes of 2.96, 1.63 and 1.33 ml./Kg. of body weight were calculated for each of these parameters. The interindividual and intraindividual variations about these means amounted to ± 30 to 50 per cent.3. In approximately 15 per cent of the dilution curves the concentration of dye in the aortic root during early systole (phase of maximal ejection) showed a transient, markedly low value compared with that of the end of diastole. This can be explained only on the basis of the preferential ejection from the heart in early systole of the undyed, newly entering blood from the left atrium, which had mixed poorly with the residual volume of the ventricle. Qualitative inspection of cineangiograms confirmed this impression and demonstrated that a residuum of contrast medium failed to mix with the incoming blood from the left atrium.4. In addition, there is evidence for the possibility of overestiination of stroke volumes from dilution curves recorded immediately proximal to the injection chamber.5. Incomplete mixing of the left artial blood with the residual volume of the ventricle precludes accurate quantitation of the changes of volume in the ventricle by the simple formulas proposed by previous authors. This phenomenon may serve to explain the considerable variability that is found in the present study and in the literature.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Increased levels of condensing enzyme are shown to occur in the sera of dogs after experimental myocardial infarction. The animals with the elevated levels also showed characteristic changes of the electrical activity of the heart and associated increases in the glutamate-oxal acetate transaminase activity of serum.Condensing enzyme has been detected in the sera of patients who suffered myocardial infarctions.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Nontoxic and toxic doses of digitalis glycoside produced a rapid release of potassium from the myocardium and from extracardiac tissues of the dog. For approximately 25 minutes after the administration of a digitalis glycoside the myocardium was in negative potassium balance and within an hour returned to positive balance. The most serious electrocardiographic changes transpired when the myocardium approached or attained potassium balance. Pretreatment with potassium chloride protected the heart against arrhythmias by increasing Ko+. Pretreatment with glucose and insulin enhanced the arrhythmic action of the digitalis glycosides presumably by producing a low serum potassium (Ko+) and possibly by modifying the state of intracellular potassium (Ki+).

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

A cold-precipitable, thrombin-coagulable protein, tentatively designated “cryoprofibrin,” was separated from plasma of rabbits treated withE. coliendotoxin. It was shown to contain fibrin-intermediates, consisting of fibrinogen that has lost only a portion of the peptides liberated during the conversion of rabbit fibrinogen to fibrin. These peptides have been called cofibrins. On reaction with thrombin, fibrinogen and cryoprofibrin yielded the same amount of cofibrin B (0.9 moles per 220,000 Gm. of fibrin clot); however, cryoprofibrin yielded 30 per cent less cofibrin A than did fibrinogen. Cryoprofibrin and fibrinogen yielded 0.7 and 1.0 moles of cofibrin A per 220,000 Gm. of fibrin, respectively. The deficit of cofibrin A in preference to cofibrin B provides evidence that, cryoprofibrin consists of fibrinogen that had lost cofibrin A by limited action of thrombin, because cofibrin A is liberated from fibrinogen by thrombin more rapidly than is cofibrin B.Only a small portion of the cryoprofibrin could have been produced by action of thrombin subsequent to exsanguination, because the plasma contained only about one-third of the cofibrin A that had been liberated from fibrin-ogen during its conversion to cryoprofibrin. Accordingly, cryoprofibrin provides a valid measure of thrombin activity in vivo, at least in the endotoxin-treated rabbits.An alternative approach to measurement of thrombin activity involving recovery of cofibrin A from urine proved inapplicable, because no confibrin A was found to be excreted in urine.An average of 0.264 ± 0.038 mg. cryoprofibrin per ml. was obtained from plasma of treated rabbits, as compared with 0.044 ± 0.016 mg. of cold-precipitable fibrinogen per ml. of normal plasma. The demonstration of increased thrombin activity after endotoxin treatment, as evidenced by the cryoprofibrin, implicates thrombin in the mechanism of fibrinoid deposition. The demonstration that cryoprofibrin consists of fibrin-intermediates supports Thomas' hypothesis that fibrinoid consists of fibrin-intermediates.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Atherosclerosis was produced in dogs by feeding them thiouracil and cholesterol. The increments in cholesterol concentration at sites along the length of the aortas of these dogs Avere determined by subtracting from the value for each site the corresponding value obtained from normal dogs. After about 1 month on the experimental regimen the cholesterol increments along the length of the aorta formed a gradient. The increment was greatest in the proximal aorta and progressively less down the length of the aorta. After about 5 months on the regimen, the gradient no longer existed. Instead, the cholesterol increment in the abdominal aorta exceeded that in the thoracic aorta. Albumin is known to enter aortic wall with a gradient of rates that is similar to the gradient of cholesterol increments early in the course of experimental atherosclerosis.The foregoing facts are consistent with the following theory: In the development of atherosclerosis, intact low-density lipoproteins containing cholesterol enter the aortic wall with a gradient of rates. They enter fastest in the proximal aorta and progressively less rapidly down the length of the aorta. However, cholesterol is removed from the abdominal aorta much more slowly than from the thoracic aorta. Thus, the increment in cholesterol concentration in the abdominal aorta eventually exceeds that in the thoracic aorta.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

A mean transcapillary exchange rate for albumin and gamma globulin has been obtained from plasma disappearance curves of I131-labeled albumin and I125-labeled gamma globulin. A much closer correlation exists between transcapillary exchange rate for albumin and the plasma volume than between the rate and serum albumin concentrations. Also, for albumin this rate varies with plasma volume and circulating protein in such a manner as to suggest that the capillary permeability changes with changing plasma volume. The relation between vascular and extravascular albumin is consistent with this interpretation, the extravascular mass of albumin appearing to approach zero as vascular albumin approaches the vicinity of 0.35 Gm/Kg. In experiments in which I131-labeled albumin and I125-labeled globulin were employed to obtain simultaneous data on albumin and gamma globulin, a good correlation has been obtained between the simultaneously measured albumin and globulin transcapillary exchange rates. The ratio of the fractional capillary exchange rates of these 2 substances is very nearly the same as the ratio of their diffusion coefficients, a relation to be expected if diffusion is the mechanism of transcapillary exchange.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The distribution and transcapillary exchange of albumin have been studied in patients with congestive heart failure and the results compared with a group of control subjects who did not have heart failure.The normal relation between vascular albumin mass and plasma volume on the one hand and transcapillary albumin exchange on the other does not exist in patients with congestive failure. The transcapillary albumin exchange rate, which presumably reflects capillary permeability, is decreased relative to the plasma volume and vascular albumin mass. It appears that decreased permeability of capillaries to albumin is associated with congestive failure and may be responsible for the increased plasma volume characteristic of this disease.The appearance of labeled protein in edema fluid has been studied in 7 patients and compared with the simultaneously determined serum disappearance curves. The albumin contained in the edema fluid constitutes a small fraction of the total extravascular albumin pool. The vascular albumin mass equilibrates less rapidly with the local edema albumin mass than with the total extravasenlar albumin mass.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID