Advances in myocardiology最新文献_第6页

The effects of intracellular Na on contraction and intracellular pH in mammalian cardiac muscle. 细胞内钠对哺乳动物心肌收缩及细胞内pH值的影响。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_24

R D Vaughan-Jones, D A Eisner, W J Lederer

引用次数: 12

Modification of the function of cardiac subcellular organelles by insulin. 胰岛素对心脏亚细胞细胞器功能的影响。

Advances in myocardiology Pub Date : 1985-01-01

G N Pierce, P K Ganguly, A Dzurba, N S Dhalla

引用次数: 0

Adenosine formation. Evidence for a direct biochemical link with energy metabolism. 腺苷酸的形成。与能量代谢有直接生物化学联系的证据。

Advances in myocardiology Pub Date : 1985-01-01

A C Newby, Y Worku, C A Holmquist

引用次数: 0

Characterization of calmodulin-dependent and cyclic-AMP-dependent protein kinase stimulation of cardiac sarcoplasmic reticulum calcium transport. 钙调素依赖性和环amp依赖性蛋白激酶刺激心肌肌浆网钙转运的表征。

Advances in myocardiology Pub Date : 1985-01-01

S Katz, B Richter, B Eibschutz

{"title":"Characterization of calmodulin-dependent and cyclic-AMP-dependent protein kinase stimulation of cardiac sarcoplasmic reticulum calcium transport.","authors":"S Katz, B Richter, B Eibschutz","doi":"","DOIUrl":"","url":null,"abstract":"The mechanism by which calmodulin stimulates Ca2+ transport in cardiac microsomal preparations enriched in sarcoplasmic reticulum (SR) was investigated. Under incubation conditions in which the majority of the phosphoprotein formed was Ca2+-dependent and no phospholamban phosphorylation was observed (10 degrees C, 15-sec incubations in the presence of 2 microM ATP), calmodulin was found to have no effect on the steady-state level of the acylphosphate phosphorylation site of Ca2+-ATPase. A significant stimulation of Mg2+, Ca2+-ATPase activity by calmodulin and a 3-fold increase in the turnover of the Ca2+ pump were, however, observed. As the ATP concentration in the incubation media was elevated (20 and 200 microM ATP), a significant degree of phosphoprotein formed was observed to be cyclic AMP (cAMP)-dependent. The degree of Ca2+-dependent phosphorylation remained constant. Under these conditions, calmodulin had no effect on the degree of phosphoprotein formed. However, when the experiments were conducted at 30 degrees C for 5 min in the presence of 500 microM ATP, a significant amount of the phosphoprotein formed was calcium-calmodulin-dependent and was additive to phosphoprotein formation observed in the presence of cAMP-dependent protein kinase. The ratio of calcium-calmodulin-dependent to cAMP-dependent phosphorylation was 1:1. K+ (110 mM) decreased the levels of phosphorylation observed in the presence of calcium and calmodulin, but had less of an effect on the levels observed in the presence of cAMP-dependent protein kinase. Autoradiographic analysis of SR membranes labeled with [32P]-ATP revealed two protein bands (24,500 and 40,000 daltons) phosphorylated in the presence of added calcium and calmodulin that were not observed in the absence of either of these additions to the reaction media. These results suggest that calmodulin stimulates Ca2+ transport by a direct effect on the Mg2+, Ca2+-ATPase. An indirect effect on Ca2+ transport via a calcium-calmodulin-dependent protein kinase, though, cannot be ruled out.","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":"6 ","pages":"233-47"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14287828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Endothelium influences coronary and aortic vasomotion by release of an unstable humoral factor. 内皮通过释放一种不稳定的体液因子影响冠状动脉和主动脉血管的运动。

Advances in myocardiology Pub Date : 1985-01-01

T M Griffith, D H Edwards, M J Lewis, A H Henderson

引用次数: 0

Extracellular structures in heart muscle. 心肌的细胞外结构。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_19

T F Robinson, L Cohen-Gould, R M Remily, J M Capasso, S M Factor

引用次数: 30

Ventricular collagen matrix and alterations. 心室胶原基质及其改变。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_20

J B Caulfield, S B Tao, M Nachtigal

{"title":"Ventricular collagen matrix and alterations.","authors":"J B Caulfield, S B Tao, M Nachtigal","doi":"10.1007/978-1-4757-1287-2_20","DOIUrl":"https://doi.org/10.1007/978-1-4757-1287-2_20","url":null,"abstract":"There is a complex extracellular structural matrix in the heart. This matrix appears to be composed of a variety of fibrils and fibers extending from the cell surface to the basal lamina and from the basal lamina to the matrix. The extensions into the extracellular region interconnect with a system of collagen bundles. The latter are so located that they would tether the myocytes to each other as well as tether the capillaries to the myocetes. There is an extensive weave of collagen analogous to the perimysium of skeletal muscle that separates groups of myocytes. The weave surrounding a group of myocytes is connected to adjacent weave patterns by long, tendonlike structures. The collagen matrix around cells disappears 2-3 hr after coronary-artery occlusion. In the periinfarct region of viable cells, the matrix is similarly lost and is replaced by scarlike collagen. Encephalomyocarditis virus causes a similar loss of the matrix in necrotic as well as some adjacent nonnecrotic regions. Replacement of the lost matrix is by scar tissue. The long-term appearance of the replacement fibrosis closely resembles the appearance of diffuse fibrosis as seen in a variety of conditions. These observations suggest that diffuse fibrosis can occur secondary to loss of the matrix both with and without myocyte necrosis. This may help explain the diffuse left ventricular fibrosis as seen in a variety of human disease.","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":"5 ","pages":"257-69"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15082602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Na-Ca exchange in cardiac tissues. 心脏组织中的Na-Ca交换。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1007/978-1-4757-1287-2_23

D Ellis

{"title":"Na-Ca exchange in cardiac tissues.","authors":"D Ellis","doi":"10.1007/978-1-4757-1287-2_23","DOIUrl":"https://doi.org/10.1007/978-1-4757-1287-2_23","url":null,"abstract":"Our awareness of the importance of Na-Ca exchange in cardiac muscle has progressed from early observations of Na-Ca antagonism in the activation of contractile force. This was followed by demonstrations of actual Na-Ca ion countertransport across cell membranes and later functional studies in which manipulation of intracellular and extracellular Na and Ca concentrations has permitted a better characterization of the exchange process and its contribution to contractile force. The recent development of vesicle preparations from cardiac sarcolemmal membranes has, despite some drawbacks, produced useful information on the electrogenicity of the exchange mechanisms and on the relative affinity of the exchange carrier compared to the ATPase-driven Ca pump. These studies confirmed earlier estimates of the approximate exchange ratio of the Na-Ca countertransport system and have demonstrated its large maximum transport rate capabilities. The application of ion-sensitive microelectrodes in recent years has enabled measurements of the actual ion-activity gradients across the sarcolemmal membrane. These activity gradients together with the membrane potential control the rate and direction of the Na-Ca exchange. Despite the wide range of techniques employed to tackle the problem, the exchange ratio of Na to Ca movement is still in some doubt, with most estimates ranging between 5:2 and 4:1.","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":"5 ","pages":"295-312"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14998698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Is the purine nucleotide cycle important in heart muscle? 嘌呤核苷酸循环在心肌中重要吗?

Advances in myocardiology Pub Date : 1985-01-01

H Taegtmeyer

{"title":"Is the purine nucleotide cycle important in heart muscle?","authors":"H Taegtmeyer","doi":"","DOIUrl":"","url":null,"abstract":"The purine nucleotide cycle catalyzes the net reaction: aspartate + GTP + H2O----fumarate + NH3 + GDP + Pi. The cycle leads to regeneration of AMP. In skeletal muscle the cycle's rate of operation increases severalfold in response to a corresponding increase in work load. This results in a net increase in citric-acid-cycle intermediates and in release of ammonia. The same may be expected in heart muscle, which, like skeletal muscle, possesses the enzymes of the purine nucleotide cycle. Isolated and working rat hearts were therefore perfused for 45 min at low or high work load (0.16 vs. 0.42 kg X m/min per g dry wt.) with glucose (5 mM) as substrate. Release of ammonia into the perfusate as well as the content of citric-acid-cycle intermediates (citrate, isocitrate, 2-oxoglutarate, malate, and oxaloacetate), related amino acids (aspartate, glutamate, and glutamine), adenine nucleotides, and creatine phosphate were measured in freeze-clamped tissue. There was no significant change between low and high work load in the sum of the citric-acid-cycle intermediates (1.295 vs. 1.313 mumole/g dry wt.), in aspartate (13.21 vs. 14.32 mumole/g dry wt.), in glutamate (15.58 vs. 15.67 mumole/g dry wt.), ATP (19.06 vs. 19.17 mumole/g dry wt.), ADP (5.00 vs. 4.11 mumole/g dry wt.), AMP (1.45 vs. 1.00 mumole/g dry wt.) or in creatine phosphate (22.58 vs. 25.80 mumole/g dry wt.). Ammonia release was 26 and 22 mumole/hr per g dry wt. at low and high work load, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)","PeriodicalId":77831,"journal":{"name":"Advances in myocardiology","volume":"6 ","pages":"165-72"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"15106643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of Ca influx in cardiac muscle excitation-contraction coupling. Assessment by extracellular Ca microelectrodes. 钙内流在心肌兴奋-收缩耦合中的作用。细胞外钙微电极评价。

Advances in myocardiology Pub Date : 1985-01-01 DOI: 10.1016/0022-2828(83)91012-x

D. Bers, D. Merrill

引用次数: 6