188 research outputs found

    Monitoring the expression of purinoceptors and nucleotide-metabolizing ecto-enzymes with antibodies directed against proteins in native conformation

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    Following their release from cells, ATP and NAD, the universal currencies of energy metabolism, function as extracellular signalling molecules. Mammalian cells express numerous purinoceptors, i.e., the nucleotide-gated P2X ion channels and the G-protein-coupled P2Y receptors. Signalling through purinoceptors is controlled by nucleotide-metabolizing ecto-enzymes, which regulate the availability of extracellular nucleotides. These enzymes include ecto-nucleoside triphosphate diphosphohydrolases (ENTPD, CD39 family) and ecto-nucleotide pyrophosphatase/phosphodiesterases (ENPP, CD203 family). Investigation of these receptors and enzymes has been hampered by the lack of available antibodies, especially ones that recognize these proteins in their native conformation. This study reports the use of genetic immunization to generate such antibodies against P2X1, P2X4, P2X7, ENTPD1, ENPTD2, ENPTD5, ENPTD6, ENPP2, ENPP3, ENPP4, ENPP5, and ENPP6. Genetic immunization ensures expression of the native protein by the cells of the immunized animal and yields antibodies directed against proteins in native conformation (ADAPINCs). Such antibodies are especially useful for immunofluorescence and immunoprecipitation analyses, whereas antibodies against synthetic peptides usually function well only in Western-blot analyses. Here we illustrate the utility of the new antibodies to monitor the cell surface expression of and to purify some key players of purinergic signalling

    High MACC1 expression in combination with mutated KRAS G13 indicates poor survival of colorectal cancer patients

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    BACKGROUND: The metastasis-associated in colon cancer 1 (MACC1) gene has been identified as prognostic biomarker for colorectal cancer (CRC). Here, we aimed at the refinement of risk assessment by separate and combined survival analyses of MACC1 expression with any of the markers KRAS mutated in codon 12 (KRAS G12) or codon 13 (KRAS G13), BRAF V600 mutation and MSI status in a retrospective study of 99 CRC patients with tumors UICC staged I, II and III. FINDINGS: We showed that only high MACC1 expression (HR: 6.09, 95% CI: 2.50-14.85, P < 0.001) and KRAS G13 mutation (HR: 5.19, 95% CI: 1.06-25.45, P = 0.042) were independent prognostic markers for shorter metastasis-free survival (MFS). Accordingly, Cox regression analysis revealed that patients with high MACC1 expression and KRAS G13 mutation exhibited the worst prognosis (HR: 14.48, 95% CI: 3.37-62.18, P < 0.001). Patients were classified based on their molecular characteristics into four clusters with significant differences in MFS (P = 0.003) by using the SPSS 2-step cluster function and Kaplan-Meier survival analysis. CONCLUSION: According to our results, patients with high MACC1 expression and mutated KRAS G13 exhibited the highest risk for metachronous metastases formation. Moreover, we demonstrated that the “Traditional pathway” with an intermediate risk for metastasis formation can be further subdivided by assessing MACC1 expression into a low and high risk group with regard to MFS prognosis. This is the first report showing that identification of CRC patients at high risk for metastasis is possible by assessing MACC1 expression in combination with KRAS G13 mutation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12943-015-0316-2) contains supplementary material, which is available to authorized users

    Modern Feynman Diagrammatic One-Loop Calculations

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    In this talk we present techniques for calculating one-loop amplitudes for multi-leg processes using Feynman diagrammatic methods in a semi-algebraic context. Our approach combines the advantages of the different methods allowing for a fast evaluation of the amplitude while monitoring the numerical stability of the calculation. In phase space regions close to singular kinematics we use a method avoiding spurious Gram determinants in the calculation. As an application of our approach we report on the status of the calculation of the amplitude for the process ppbbˉbbˉ+Xpp\to b\bar{b}b\bar{b}+X.Comment: 10 pages, 2 figures; contribution to the proceedings of the CPP2010 Workshop, 23-25 Sep. 2010, KEK, Tsukuba, Japa

    Replicative senescence of mesenchymal stem cells causes DNA-methylation changes which correlate with repressive histone marks

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    Cells in culture undergo replicative senescence. In this study, we analyzed functional, genetic and epigenetic sequels of long-term culture in human mesenchymal stem cells (MSC). Already within early passages the fibroblastoid colonyforming unit (CFU-f) frequency and the differentiation potential of MSC declined significantly. Relevant chromosomal aberrations were not detected by karyotyping and SNP-microarrays. Subsequently, we have compared DNA-methylation profiles with the Infinium HumanMethylation27 Bead Array and the profiles differed markedly in MSC derived from adipose tissue and bone marrow. Notably, all MSC revealed highly consistent senescence-associated modifications at specific CpG sites. These DNA-methylation changes correlated with histone marks of previously published data sets, such as trimethylation of H3K9, H3K27 and EZH2 targets. Taken together, culture expansion of MSC has profound functional implications - these are hardly reflected by genomic instability but they are associated with highly reproducible DNA-methylation changes which correlate with repressive histone marks. Therefore replicative senescence seems to be epigenetically controlled

    The Multiple Signaling Systems Regulating Virulence in Pseudomonas aeruginosa

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    Cell-to-cell communication is a major process that allows bacteria to sense and coordinately react to the fluctuating conditions of the surrounding environment. In several pathogens, this process triggers the production of virulence factors and/or a switch in bacterial lifestyle that is a major determining factor in the outcome and severity of the infection. Understanding how bacteria control these signaling systems is crucial to the development of novel antimicrobial agents capable of reducing virulence while allowing the immune system of the host to clear bacterial infection, an approach likely to reduce the selective pressures for development of resistance. We provide here an up-to-date overview of the molecular basis and physiological implications of cell-to-cell signaling systems in Gram-negative bacteria, focusing on the well-studied bacterium Pseudomonas aeruginosa. All of the known cell-to-cell signaling systems in this bacterium are described, from the most-studied systems, i.e., N-acyl homoserine lactones (AHLs), the 4-quinolones, the global activator of antibiotic and cyanide synthesis (GAC), the cyclic di-GMP (c-di-GMP) and cyclic AMP (cAMP) systems, and the alarmones guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), to less-well-studied signaling molecules, including diketopiperazines, fatty acids (diffusible signal factor [DSF]-like factors), pyoverdine, and pyocyanin. This overview clearly illustrates that bacterial communication is far more complex than initially thought and delivers a clear distinction between signals that are quorum sensing dependent and those relying on alternative factors for their production

    Повышение эффективности противопожарной защиты магазина «Fix Price»

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    Целью работы является усовершенствование системы противопожарной защиты магазина "Fix Price". В выпускной квалификационной работе проведен обзор литературных источников по вопросам состояния проблем обеспечения пожарной безопасности на предприятиях торговли, дан анализ автоматических систем пожаротушения, обоснован выбор автоматической установки пожаротушения тонкораспылённой водой для объекта исследования, произведены расчёты индивидуального пожарного риска.The aim of the work is to improve the fire protection system of the "Fix Price" store. In the final qualifying work, a review of literature sources on the state of problems of fire safety in commercial enterprises is conducted, an analysis of automatic fire extinguishing systems is given, the choice of an automatic fire extinguishing system with thin-sprayed water for the object of research is justified, and calculations of individual fire risk are made

    Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

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    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology

    Wissenschaftliche Begründung der STIKO zur Auffrischimpfung von Personen ≥ 12 Jahren mit einem Omikron-BA.1- oder einem Omikron-BA.4/5-adaptierten bivalenten mRNA-Impfstoff

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    Die STIKO empfiehlt in der 22. Aktualisierung ihrer COVID-19-Impfempfehlung für Auffrischimpfungen ab 12 Jahren vorzugsweise einen der zugelassenen und verfügbaren Omikron-adaptierten bivalenten mRNA-Impfstoffe einzusetzen. Wie das Epidemiologische Bulletin 40/2022 ausführt, gilt dies sowohl für die BA.1- als auch für die BA.4/5-adaptierten Impfstoffe, da beide im Vergleich zu den bisherigen monovalenten mRNA-Impfstoffen eine verbesserte Antikörperantwort gegenüber verschiedenen Omikron-Varianten auslösen und gegenüber dem SARS-CoV-2-Wildtypstamm eine gleichbleibend gute Antikörperantwort erzielen. Es ist trotz der limitierten Datenlage anzunehmen, dass die bivalenten Impfstoffe ebenso wie die herkömmlichen monovalenten Impfstoffe Schutz vor schweren Infektionen, Hospitalisierung und Tod durch jede der bisher aufgetretenen SARS-CoV-2-Varianten vermitteln
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