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Changes in the hemostatic system and compensatory responses during alimentary hyperlipidemia. 消化性高脂血症期间止血系统和代偿反应的变化。
Biomedica biochimica acta Pub Date : 1991-01-01
F J Lucio, M R Puyol, L D Marques, C G Escribano, A M Duarte
{"title":"Changes in the hemostatic system and compensatory responses during alimentary hyperlipidemia.","authors":"F J Lucio,&nbsp;M R Puyol,&nbsp;L D Marques,&nbsp;C G Escribano,&nbsp;A M Duarte","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Compensatory responses tending to prevent a thrombotic state in rats fed a high lipid diet have been investigated. Platelet membranes from these animals had an increased cholesterol content but the membrane fluidity was found to be within values nearly normal. A decrease in phosphatidylethanolamine was noted. These changes may maintain normal platelet sensitivity to aggregating agents. In fact, platelets from hyperlipidemic rats were hypersensitive to thrombin, but not to adenosine diphosphate. In addition, platelets were apparently able to correct, at least in part, the stated hyperactivity of hyperlipidemic plasma to coagulate, as shown by thrombelastographic tests in both platelet-rich plasma and plasma from hyperlipidemic rats. Finally, thrombelastographic features of whole blood from these animals were found to be normal. This suggests an important role of blood cells in compensating plasma hyperactivity to coagulate during hyperlipidemia.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12923717","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 HIV-1 gag precursor is processed via two pathways: implications for cytotoxicity. HIV-1 gag前体通过两种途径加工:细胞毒性的影响。
Biomedica biochimica acta Pub Date : 1991-01-01
A H Kaplan, R Swanstrom
{"title":"The HIV-1 gag precursor is processed via two pathways: implications for cytotoxicity.","authors":"A H Kaplan,&nbsp;R Swanstrom","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>All retroviruses studied thus far contain proteases which process viral precursors to liberate the structural and enzymatic proteins of the viral capsid. We have examined the processing of the Gag precursor of HIV-1 which is composed of the viral structural proteins. Our results indicate that Gag is processed via two pathways: an expected membrane-associated pathway which gives rise to virions and a cytoplasmic pathway in which processed viral proteins accumulate in the cytoplasm. The presence of an active protease in the cytoplasm of infected cells is a potential source of toxicity. A comparison of the extent of cytoplasmic processing in lytically infected cells compared with that in cells which are not killed by the virus demonstrates a close correlation between cytoplasmic processing and cell killing.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12963458","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
Peptide inhibitors and the active site(s) of angiotensin converting enzyme. 肽抑制剂和血管紧张素转换酶的活性位点。
Biomedica biochimica acta Pub Date : 1991-01-01
J F Riordan, Y N Chen, S G Kleemann, P Bünning
{"title":"Peptide inhibitors and the active site(s) of angiotensin converting enzyme.","authors":"J F Riordan,&nbsp;Y N Chen,&nbsp;S G Kleemann,&nbsp;P Bünning","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Angiotensin converting enzyme (ACE) is a central participant in blood pressure regulation and is strategically located within the pulmonary vasculature in order to carry out this function. It is also present in kidney, brain and a variety of other tissues where its function is unknown. The molecular weight of ACE from these sources is approximately 185,000. A smaller form of the enzyme, Mr approximately 100,000, is found in mature testis; its function is also unknown. The lung form of human ACE contains 1277 amino acids and consists of two homologous repeated domains, each of which appears to have a potential catalytic site. The testis form of human ACE contains 701 amino acids and has only a single domain which is largely identical to the carboxy-terminal half of the lung enzyme. This raises important questions such as, why does lung ACE possess two possible active sites, do each of the two bind zinc, and are they both catalytically active? To answer these questions, we have examined the binding of potent peptide inhibitors to ACE, redetermined the zinc stoichiometry and chemically modified both lung and testicular ACE with fluorodinitrobenzene (FDNB). Peptide inhibitors bind with essentially a 1:1 stoichiometry, indicative of a single active site. The zinc content of lung ACE is 1.4-1.8 g-at/mol. For testicular ACE it is 0.8-1.1 g-at/mol. FDNB modifies a single tyrosine, and to a much lesser extent a lysine, with concomitant loss of all catalytic activity. Sequence analysis identifies the specific residues modified and indicates that they occur only in the carboxy terminal half of lung ACE.(ABSTRACT TRUNCATED AT 250 WORDS)</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12832284","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
Intramitochondrial fatty acid activation enhances control strength of adenine nucleotide translocase. 线粒体内脂肪酸活化增强了腺嘌呤核苷酸转位酶的控制强度。
Biomedica biochimica acta Pub Date : 1991-01-01
P Schönfeld, R Bohnensack
{"title":"Intramitochondrial fatty acid activation enhances control strength of adenine nucleotide translocase.","authors":"P Schönfeld,&nbsp;R Bohnensack","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In incubations with isolated rat liver mitochondria we studied the fuel properties of octanoate as medium-chain fatty acid and respiratory substrate and the extent of control exerted by adenine nucleotide translocase on mitochondrial respiration. While, compared with pyruvate, octanoate improved the hydrogen supply in the active state to be seen from a high reduction of the mitochondrial NAD(P) system and an increased delta psi, it also decreased the efficiency of energy transduction indicated by a low ADP/O ratio. Based on measurements of the dependence of respiration on the extramitochondrial ATP/ADP ratio, we conclude that a switch-over from pyruvate to fatty acid oxidation does not change the kinetic parameters which make respiration respond to the ATP/ADP ratio. It is shown that the decrease of the exchangeable intramitochondrial adenine nucleotide pool due to the activation of octanoate results in a decrease of the activity of the adenine nucleotide translocase and an increase of its flux control coefficient.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12923712","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
Influence of urea on the glucose measurement by electrocatalytic sensor in the extracorporeal blood circulation of a sheep. 尿素对绵羊体外血液循环中电催化传感器测定葡萄糖的影响。
Biomedica biochimica acta Pub Date : 1991-01-01
S Saeger, W Preidel, I von Lucadou, L Ruprecht, W Lager
{"title":"Influence of urea on the glucose measurement by electrocatalytic sensor in the extracorporeal blood circulation of a sheep.","authors":"S Saeger,&nbsp;W Preidel,&nbsp;I von Lucadou,&nbsp;L Ruprecht,&nbsp;W Lager","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In an animal experiment with the electrocatalytic glucose sensor, measurements were carried out over one week in the extracorporeal circulation of a sheep. Glucose tolerance tests were performed, and the influence of increased urea concentrations in the blood on the glucose determination was investigated. The sensor constructed as a flow-through cell was integrated via a vascular graft outside the body into the carotid artery of the animal and activated by an external electronic unit of measurement. The glucose concentration was determined by measuring the impedance of the electrode/membrane system at various potentials. By means of a subsequent correlation analysis of the measured values obtained over one week, a calibration valid for the entire measurement period was established. After a zero adjustment, it was even possible to adopt the calibration from the glucose measurement of the preceding animal experiment. The investigations of the influence of urea on the glucose measurement showed that the error in measurement of the sensor, which is 20% on average, is only insignificantly increased when the urea level is raised beyond the maximum physiological concentration.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12923716","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
Effects of salicylate on hepatocyte lactate metabolism. 水杨酸对肝细胞乳酸代谢的影响。
Biomedica biochimica acta Pub Date : 1991-01-01
R Rognstad
{"title":"Effects of salicylate on hepatocyte lactate metabolism.","authors":"R Rognstad","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We have examined the effects of salicylate on fluxes of lactate metabolism in rat hepatocytes using a steady state model. Salicylate produces an uncoupling effect, an inhibition of gluconeogenesis, a marked activation of pyruvate dehydrogenase flux, and an inhibition of endogenous fatty acid oxidation. Agents with known functions such as dinitrophenol and dichloroacetate were also compared in this system. The in vitro inhibition of gluconeogenesis caused by salicylate is not primarily related to the uncoupling effect. The fact that octanoate, but not palmitate, overcomes the salicylate inhibition of gluconeogenesis suggests that salicylyl CoA is involved in the inhibition. To relate in vitro studies to Reye's syndrome in vivo, in which medium chain dicarboxylic acids accumulate, we have also examined the effects of monomethyl suberate on liver lactate metabolism. This half ester is taken up by the hepatocytes, and causes inhibition of lactate gluconeogenesis, and uncoupling. Both salicylate and monomethyl suberate inhibit the oxidation of 0.2 mM octanoate by hepatocytes.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12922297","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
Does Tris-HCl effectively participate in transamination during hemoglobin pyridoxylation? Tris-HCl是否有效参与血红蛋白吡哆基化过程中的转氨化?
Biomedica biochimica acta Pub Date : 1991-01-01
P Menu, C Geschier, C Vigneron, P Labrude
{"title":"Does Tris-HCl effectively participate in transamination during hemoglobin pyridoxylation?","authors":"P Menu,&nbsp;C Geschier,&nbsp;C Vigneron,&nbsp;P Labrude","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>To test whether Tris is required for covalent binding of pyridoxal phosphate (PLP) to hemoglobin, we carried out the reaction in solutions of Tris homologues, carrying a blocked amine function. With the exception of Mono-Tris, these compounds permitted the synthesis of modified hemoglobins with acceptable spectral properties, P50 values, cooperativity and methemoglobin content, refuting Tris HCI participation during hemoglobin pyridoxylation.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12944258","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
Sequence comparison among subunits of multicatalytic proteinase. 多催化蛋白酶亚基序列比较。
Biomedica biochimica acta Pub Date : 1991-01-01
H Sorimachi, H Kawasaki, T Tsukahara, S Ishiura, Y Emori, H Sugita, K Suzuki
{"title":"Sequence comparison among subunits of multicatalytic proteinase.","authors":"H Sorimachi,&nbsp;H Kawasaki,&nbsp;T Tsukahara,&nbsp;S Ishiura,&nbsp;Y Emori,&nbsp;H Sugita,&nbsp;K Suzuki","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The cDNAs for a number of multicatalytic proteinase (MCP) subunits have been cloned, characterized, and their primary structures have been determined. The mechanism for how MCP demonstrates its multicatalytic nature, especially protease activities, however, is still obscure, since no sequences similar to known protease sequences can be found in the sequences of MCP subunits thus far determined. To explain this fact, we propose a structural model for MCP: MCP consists of two classes of subunits, structural and catalytic, and the structural subunits constitute a \"test-tube\"-like container in which the other catalytic subunits sit and react with substrate. Most of the observations thus far obtained can be explained easily by this hypothesis, although various other possibilities are not excluded.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12964699","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
Probing the specificity of the bovine pituitary multicatalytic proteinase complex by inhibitors, activators, and by chemical modification. 通过抑制剂、激活剂和化学修饰探讨牛垂体多催化蛋白酶复合物的特异性。
Biomedica biochimica acta Pub Date : 1991-01-01
S Wilk, M Pereira, B Yu
{"title":"Probing the specificity of the bovine pituitary multicatalytic proteinase complex by inhibitors, activators, and by chemical modification.","authors":"S Wilk,&nbsp;M Pereira,&nbsp;B Yu","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12964701","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
Calpain and kininogen mediated inflammation. 钙蛋白酶和激肽原介导的炎症。
Biomedica biochimica acta Pub Date : 1991-01-01
M Sasaki, M Kunimatsu, T Tada, J Nishimura, X J Ma, I Ohkubo
{"title":"Calpain and kininogen mediated inflammation.","authors":"M Sasaki,&nbsp;M Kunimatsu,&nbsp;T Tada,&nbsp;J Nishimura,&nbsp;X J Ma,&nbsp;I Ohkubo","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>On the basis of previous findings that N-acetyl nonapeptide from the human calpain I large subunit has chemotactic activity for neutrophils, more than 30N-acetyl and unmodified peptides which have N-terminal amino acid sequences of the large and small subunits of calpains I and II were synthesized and their chemotactic activity was estimated. In addition to the above N-acetyl nonapeptide from the calpain I large subunit, an unmodified nonapeptide from the calpain II large subunit and several N-acetyl peptides of different lengths from the small subunit showed chemotactic activity. Furthermore, when calpain was incubated with either high molecular weight or low molecular weight kininogen, kinin liberation occurred with simultaneous inhibition of calpain by kininogen. These data suggest that chemical mediators generated from the calpain-kininogen system may participate in migration and accumulation of neutrophils to the inflammatory locus.</p>","PeriodicalId":8948,"journal":{"name":"Biomedica biochimica acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12964705","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
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