Cellular & molecular biology research最新文献

{"title":"The effect of long-term bradycardia on heart microvascular supply and performance.","authors":"M D Brown,&nbsp;M K Davies,&nbsp;O Hudlicka","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Bradycardia has been shown to be beneficial for the normal and ischaemic heart because it improves diastolic perfusion and oxygen supply demand balance. Experimentally, a chronically induced decrease in heart rate, either by electrical pacing or pharmacological means, was found previously to increase myocardial capillary supply in normal rabbit and rat hearts. These studies have been extended to a larger mammal, the pig, in which a direct bradycardia (approximately 30% decrease in heart rate) was induced by electrical pacing for 4-5 weeks. There was no evidence of heart hypertrophy and capillary density was found to be significantly increased in the left, but not right, ventricle. Cardiac function during dobutamine inotropic challenge was better in pig hearts which had been paced bradycardially. They performed greater stroke work-higher stroke flow output at lower heart rate--for similar coronary blood flow, thus demonstrating an improved economy of flow utilisation. Heart rate reduction may facilitate capillary growth in the absence of cardiac hypertrophy by prolonging diastolic perfusion, and/or mechanical stretch of vessels due to increased stroke volume capacity. In either case, capillaries would be exposed to increased wall tension which could trigger angiogenesis.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 2","pages":"137-42"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18539282","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}

{"title":"Structure and function of Saccharomyces cerevisiae casein kinase II.","authors":"C V Glover,&nbsp;A P Bidwai,&nbsp;J C Reed","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Analysis of casein kinase II in organisms amenable to genetic manipulation is essential to elucidating the physiological function(s) of this ubiquitous protein kinase. This paper summarizes work from our laboratory on the enzyme from Saccharomyces cerevisiae. The biochemistry, molecular biology, and genetics of S. cerevisiae casein kinase II are reviewed and discussed.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 5-6","pages":"481-8"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18736165","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}

{"title":"Bibliography of cellular and molecular biology research.","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 7-8","pages":"709-21"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18790675","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}

{"title":"Cardiac muscle and its blood supply: palaeophysiological notes.","authors":"O Poupa","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 2","pages":"153-65"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18849385","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}

{"title":"Bibliography of cellular and molecular biology research.","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 2","pages":"167-72"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18849386","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}

{"title":"Protein kinase CKII: possible regulation by interaction with protein substrates.","authors":"M Plana,&nbsp;C Gil,&nbsp;E Molina,&nbsp;E Itarte","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Rat liver cytosolic CKII shows heterogeneity resulting from association of the alpha/alpha'-subunits with the beta-subunit or with a phosphorylatable protein of 49 kDa (pp49). Preparations of pp49 were resolved into several spots by two dimensional analysis which might be derived from different degrees of phosphorylation. pp49 was phosphorylated in vitro by purified rat liver CKII and to a lower extent by purified rat brain protein kinase C. In all cases, phosphorylation of pp49 occurred exclusively on Ser. Phosphopeptide maps of phosphorylated pp49 confirmed that the phosphorylation by CKII or PKC takes place in different sites. Prior phosphorylation of pp49 by protein kinase C had no significant influence on the increase of the Km value for beta-casein of CKII, caused by pp49. A tryptic peptide from pp49 has been recently sequenced and antibodies against it had been raised. The antibodies were able to recognize pp49 in rat liver extracts as well as in HL-60 extracts what leads us to presume that this kind of interaction might exist in other species and tissues.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 5-6","pages":"455-61"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18736243","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}

{"title":"Thyroid hormone regulation of Na,K-ATPase alpha 2 gene expression in cardiac myocytes.","authors":"F Huang,&nbsp;H He,&nbsp;G Gick","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Thyroid hormone (T3) stimulates Na,K-ATPase activity and alpha and beta subunit mRNA abundances in myocardial cells in vivo and in vitro. In this study, we used transient transfection and nuclear run-on assays to determine whether T3 regulates the transcription rate of the Na,K-ATPase alpha 2 subunit gene. Primary cultures of neonatal rat cardiac myocytes were incubated with 100 nM T3 for 1, 3, and 6 d, and alpha 2 mRNA levels were measured by Northern blot hybridization analysis. There was no change in the abundance of alpha 2 mRNA by 1 d of T3 treatment, whereas a two- and threefold increase in alpha 2 mRNA was evident when cells were exposed to T3 for 3 and 6 d, respectively. A portion of the rat alpha 2 gene containing 1700 base pairs (bp) of 5'-flanking DNA sequence was isolated and fused to the firefly luciferase gene. Transient transfection experiments utilizing this chimeric gene showed no T3 trans-activation of reporter gene activity either in the absence or presence of cotransfected beta 1 or alpha 1 isoforms of rat T3 receptor (T3R). In contrast, cotransfection of T3R facilitated a strong stimulation of luciferase activity driven by a construct containing a single copy of a palindromic T3 response element (TRE). Nuclear run-on analysis indicated that the rate of transcription of the endogenous alpha 2 gene was enhanced 1.2-fold at 3 d of T3 treatment, and was not regulated at either 1 or 6 d. These results indicate that the T3-dependent increase in alpha 2 mRNA content at 6 d is mediated at a post-transcriptional level. Unexpectedly, we observed a T3-dependent three-to sixfold repression of alpha 2/luciferase expression in cardiac myocytes cotransfected with T3R. Deletion analysis of the 5' end of the alpha 2 gene revealed a negative TRE between nucleotides -354 and -100.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 1","pages":"41-52"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18804666","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}

{"title":"Dinucleotide repeat polymorphisms at nine loci in sporadic colorectal cancer.","authors":"U Patel,&nbsp;H C Chen,&nbsp;S Banerjee","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Genomic instability in the form of microsatellite alterations at nine loci on chromosomes 2p, 8p, 10p, 11p, and nm23-H1 locus on 17q21.3 were studied in sporadic colorectal tumors. Alterations in dinucleotide repeats in tumor DNA as larger allele, smaller allele, or loss of heterozygosity (LOH) were observed. Forty percent of tumor showed an RER+ phenotype. A significantly high number of alterations was detected at loci of chromosome 8p. The markers on chromosomes 2p, 10p, and 11p did not show such significant alteration. LOH was found to be associated with the nm23-H1 locus. No correlation was found between the age, site of tumor occurrence, or metastasis and the microsatellite instability.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 7-8","pages":"683-91"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18790673","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}

{"title":"Mechanical factors involved in the growth of the heart and its blood vessels.","authors":"O Hudlicka","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Various proteins of cardiac myocytes are preprogrammed at a very early stage of heart development, but functional load (stretch, pressure) plays an important role in their expression under both physiological and pathological circumstances. Mechanical factors are also important in growth of vessels, particularly with respect to hypertrophy or hyperplasia of vascular smooth muscle. Their effect on growth of endothelial cells is less clear. Although they have been studied in cell culture, little is known about their involvement in capillary growth in vivo. Their possible role is considered in capillary growth in the normal adult heart where it was elicited by long-term administration of various vasodilators, by long-term bradycardia, or by increased inotropic action. Here the mechanical stimuli may act either by increased shear stress (resulting from increased velocity of flow in long-term dilatation) or by increasing vessel wall tension (in conjunction with increased diameters and/or stretch produced by increased inotropism). While the role of growth factors in the development of myocytes has been established, it is still questionable in capillary growth. It is also possible that various growth factors exert their effect on vessel growth by their vasoactive activity.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 2","pages":"143-52"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18849384","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}

{"title":"The expression and processing of human beta-amyloid peptide precursors in Saccharomyces cerevisiae: evidence for a novel endopeptidase in the yeast secretory system.","authors":"V Hines,&nbsp;W Zhang,&nbsp;N Ramakrishna,&nbsp;J Styles,&nbsp;P Mehta,&nbsp;K S Kim,&nbsp;M Innis,&nbsp;D L Miller","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In mammalian cells, the transmembrane beta-amyloid peptide precursor (beta-APP) undergoes a complex series of alternative proteolytic processing steps that result in the secretion of varying proportions of its extra-cellular domain (protease nexin II) and beta-amyloid peptide. The protein is also reinternalized and degraded in the endosomal-lysosomal system. The relative efficiencies of these competing processes determine the yield of beta-amyloid peptide. Several proteases have been implicated in this complex processing pathway, although none has been identified to date. The yeast secretory system contains proteases homologous to mammalian pro-hormone convertases and is susceptible to genetic manipulation. We therefore investigated the expression and processing of the beta-amyloid peptide precursors (beta-APP-695 and beta-APP-751) in Saccharomyces cerevisiae transformed with human beta-APP cDNA's. beta-APP (695 or 751) cDNA either with its authentic signal sequence or the yeast-derived prepro-alpha-factor leader, was inserted into a glucose-regulated expression vector and transfected into a protease-deficient yeast strain. In all instances, expression of beta-APP was about 1% of total protein. Protease protection studies indicated that either the natural human signal sequence or the alpha-factor leader sequence targetted beta-APP to the endoplasmic reticulum and inserted it with the amino-terminal domain in the lumen. All of the beta-APP fused to the alpha-factor leader proceeded to the trans-Golgi, where Kex2 endopeptidase removed the leader and released the normal amino-terminus of beta-APP. About one-half of the beta-APP was also cleaved at the \"alpha-secretase\" site in the middle of the beta-peptide sequence, 12 residues before the membrane-spanning sequence. A fraction of the alpha-secretase-cleaved beta-APP appeared in the culture medium; however, most of it associated with the exterior of the cells. The carboxyl-terminal fragments formed by cleavage at the alpha-secretase site accumulated in the membranes. Other proteolytic processes generated membrane-associated carboxyl-terminal fragments that also resembled those found in mammalian cells. These results indicate that the secretory system of S. cerevisiae possesses proteases with specificities similar to the mammalian enzymes that process beta-APP.</p>","PeriodicalId":72545,"journal":{"name":"Cellular & molecular biology research","volume":"40 4","pages":"273-84"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18864048","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}