ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Tissue mast cells have been a source of great curiosity since their conclusive description by Ehrlich over 80 years ago. They have been implicated in a vast majority of connective tissue reactions both of physiologic and pathologic nature. In some species at least, mast cells have been implicated in the production, storage and release of potent cardiovascular substances including heparin, serotonin and histamine.The present report is directed particularly toward man. Evidence is presented suggesting that human tissue cells previously lumped into one large group on the basis of granular metachromasia and termed tissue mast cells, represent at least two morphologically distinct cellular types. Difference in function of these cells may be great. There is evidence that one type may be a local tissue source for epinephrine, norepinephrine, or both. It is suggested that mast cells as a whole may represent a spectrum of cell types having numerous differences in ultrastructure and function. It is believed that their continued study in various physiologic and pathologic states should prove fruitful.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Investigation of phosphate metabolism with the aid of labeled phosphorus has been carried out, using isolated heart preparations in which only the left ventricles perform external work. The corresponding right ventricles in such preparations perform no external work with the unique experimental advantage of a single heart, providing simultaneously both working and “resting” (nonworking) metabolic states.Comparative incorporation of labeled phosphorus into nucleotide phosphate groups, non-nucleotide soluble phosphorylated components, phospholipids and ribose nucleic acid was examined as a function of cardiac work. Incorporation of the label into the rapidly exchanged high-energy phosphate groups was found to be restricted by a prior rate—limiting entry of the externally perfused isotope into the cells, thereby precluding a measure of turnover of these groups by this technic. Differences could not be demonstrated in isotope incorporation in either the phospholipids or RNA of working as compared to nonworking myocardium. It was concluded from these results that RNA is clearly not involved in energy reactions associated with cardiac work function. Phospholipid participation, on the other hand, could be clearly excluded only insofar as the phosphate moiety of these compounds is concerned.Information relevant to a mechanism of phosphate entry into cardiac cells was obtained in which a phosphorylation of hexose appeared to be involved. The composition of cardiac tissue with respect to nucleotide and non-nucleotide soluble components was examined in working and nonworkiug myocardium. Differences in composition were not found with respect to these constituents. A major component appearing in extracts of cardiac tissue was found and subsequently identified to be α-glycerophosphate. On the basis of isotope incorporation data, it was concluded that its metabolic source was of carbohydrate rather than phospholipid origin.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The response of the sensitized guinea pig heart to perfusion, with an effective dose of ovalbumin, was found to consist of an acceleration of the rate, an increase in the amplitude of contraction, and a decrease in coronary flow, confirming the earlier observations of Wilcox and Andrus. The characteristic mechanical reaction of the isolated atria was an increase in amplitude and frequency of contraction, the more intense effects resulting in fibrillation. Electrophysiologically, atrial activity was demonstrable by bursts of action potentials, recurring as soon as the membrane had repolarized sufficiently to be re-excited. The resting potential was reduced, and the overshoot and the rate of rise of the action potential were diminished.All of the mechanical and electrical events noted in the Langendorff heart and the atrial preparations during anaphylaxis could be reproduced precisely by an appropriate dose of histamine. Evidence for the release of histamine by both the perfused heart and the isolated atria was first obtained by pharmacologic methods and then confirmed by paper chromatography of butanolic extracts.*Histamine was quantitatively estimated by a bioassay method which is discussed in detail in this report.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Subcutaneous injection of carrageenan, a sulfated polygalactose extracted from the red algaeChondrus crispus, stimulated the production of fibrous connective tissue in the rabbit. Animals fed cholesterol for 3 and 5 weeks had significantly higher phospholipid concentrations in this connective tissue than did control rabbits, but no alteration in phospholipid specific activity. These results are similar to those obtained in preliminary studies of connective tissue cultured by the sponge implantation technic.Significant increases occurred in cephalin, lecithin, and sphingomyelin concentrations in tissue proliferated after cearrageenan injection. The cholesterol content of connective tissue was increased 7- to 8-fold.Histologically, the tissue taken after 3 weeks of cholesterol feeding could not be distinguished from that of control animals. At 5 weeks, connective tissue from cholesterol-fed rabbits contained mature fat cells and macrophages resembling foam cells, in addition to the fibroblasts and collagen present in control tissue. Development of collagenous fibers and alterations in lipids were not found to be directly related. It is suggested that the elaboration of collagen and the accumulation of phospholipid, both of which occur in experimental atheromatosis, represent independent processes of connective tissue cells.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Accelerated recovery, as manifested by shortening of the effective refractory period after coronary artery ligation, occurred at either the epicardial or endocardial surface or both in 11 of 13 animals tested with a mean shortening of 15.7 per cent at the epicardial and 13 per cent at the endocardial levels. These changes are attributed to severe anoxia and are believed to be limited to the ischemic area, since studies in the periphery of an infarcted zone show no significant changes in the first 3 hours. In one instance a minor acceleration of recovery was found after 3 hours at the endocardium. All studies showed a final period of delayed recovery. It is felt that this probably reflects a prolonged duration of the membrane action potential during the later stages of myocardial infarction. This is supported by both experimental and human electrocardiographic data which show prolongation of the Q-T interval in association with deeply inverted T waves following the period of acute injury. Transmural temperature studies after coronary artery ligation showed a prompt fall in 2 studies out of 7 and no acute change in the others. Irrigating the pericardial sac with warm Ringer's solution reversed the pre-existing transmural temperature gradient, caused the T waves in epicardial leads to change from negative to positive, and reduced the duration of the effective refractory period at both the endocardial and epicardial surfaces, especially the latter. During the time that the T waves were upright, recovery was completed earlier at the epicardial than at the endocardial surface.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Heart tissue from dogs in which myocardial infarction was induced experimentally was analyzed histochemically and chromatographically for plasmalogens. A new, nitrogen-free plasmalogen was observed that was confined to the infarcted area; marked histochemical alterations in the pattern of distribution of the plasmalogens occurred. The new plasmalogen is believed to be a polymer of phosphatidic acid plasmalogen.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

The level of dietary protein influenced the rate of cholesterol-4-C14catabolism in bile duct cannulated chicks and rats. Animals which had been kept on a high protein diet for 5 weeks excreted cholesterol-4-C14as bile acids at a faster rate than those on a low protein diet. The presence of dietary cholesterol did not change the rate of cholesterol-4-C14catabolism at either high or low dietary protein levels. A species difference in the rate of cholesterol catabolism was also noted. Bile duct cannulated chicks excreted an average of only 8 per cent, while bile duct cannulated rats excreted as much as 46 per cent of injected cholesterol-4-C14in a 72 hour period. It was shown that cannulation of the bile ducts caused a significant decrease in the serum cholesterol and serum β-lipoprotein levels in chicks. Furthermore, the liver cholesterol level did not seem to influence the rate of cholesterol catabolism. Serum cholesterol, especially in the form of low Sf β-lipoproteins, appeared to be used rapidly for the conversion of cholesterol to bile acids.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Treatment of kidney encapsulated rats with 850 μC. of radioactive iodine effectively prevented both the characteristic rise of blood pressure to hypertensive levels and cardiac hypertrophy. Iodine-deficient diet was ineffective under these conditions. Once hypertension was established, treatment with 850 μC. radioactive iodine lowered blood pressure toward normal levels although a significant decrease in heart weight was not observed. The iodine-deficient diet was also ineffective under these conditions. It is felt that hypothyroidism produced by administration of high doses of radioactive iodine is as effective in preventing blood pressure rise as that observed with propylthiouracil treatment. The antihypertensive effect of these antithyroid treatments appears to be the direct result of inhibition of secretion of thyroid hormone.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID

摘要:

Rabbits pretreated with Aminopterin (4-amino pteroylglutamic acid) for 4 weeks were fed an atherogenic diet for 8 weeks, during which Aminopterin injections also were continued. The atherogenic diet consisted of a stock diet with 3/4 per cent cholesterol added. As a result of some manipulation of the Aminopterin dosage during the period before cholesterol feeding was begun, some of the Aminopterin-treated animals lost weight from overdosage, and 7 of the original 20 died. The surviving animals upon reduction of dosage made good weight gains, comparable to the controls, during the cholesterol feeding period. When sacrificed after 8 weeks of cholesterol feeding, the control animals, 21 in number, all had grossly demonstrable 1+ to 4+ atheromatosis of the aorta. Of the 13 surviving Aminopterin-treated animals, 9 had no atheromatosis or doubtful deposits of minimal extent. Only 4 had definite atheromatosis comparable in extent to the controls. Serum cholesterol levels were 30 to 50 per cent lower in the treated animals than in the controls.

ISSN:0009-7330    

出版商:OVID    

年代:1960

数据来源: OVID