913 resultados para réarrangement de Beckmann


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BACKGROUND: HIV-1 infected individuals have an increased cardiovascular risk which is partially mediated by dyslipidemia. Single nucleotide polymorphisms in multiple genes involved in lipid transport and metabolism are presumed to modulate the risk of dyslipidemia in response to antiretroviral therapy. METHODS: The contribution to dyslipidemia of 20 selected single nucleotide polymorphisms of 13 genes reported in the literature to be associated with plasma lipid levels (ABCA1, ADRB2, APOA5, APOC3, APOE, CETP, LIPC, LIPG, LPL, MDR1, MTP, SCARB1, and TNF) was assessed by longitudinally modeling more than 4400 plasma lipid determinations in 438 antiretroviral therapy-treated participants during a median period of 4.8 years. An exploratory genetic score was tested that takes into account the cumulative contribution of multiple gene variants to plasma lipids. RESULTS: Variants of ABCA1, APOA5, APOC3, APOE, and CETP contributed to plasma triglyceride levels, particularly in the setting of ritonavir-containing antiretroviral therapy. Variants of APOA5 and CETP contributed to high-density lipoprotein-cholesterol levels. Variants of CETP and LIPG contributed to non-high-density lipoprotein-cholesterol levels, a finding not reported previously. Sustained hypertriglyceridemia and low high-density lipoprotein-cholesterol during the study period was significantly associated with the genetic score. CONCLUSIONS: Single nucleotide polymorphisms of ABCA1, APOA5, APOC3, APOE, and CETP contribute to plasma triglyceride and high-density lipoprotein-cholesterol levels during antiretroviral therapy exposure. Genetic profiling may contribute to the identification of patients at risk for antiretroviral therapy-related dyslipidemia.

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We report the characterisation of 27 cardiovascular-related traits in 23 inbred mouse strains. Mice were phenotyped either in response to chronic administration of a single dose of the beta-adrenergic receptor blocker atenolol or under a low and a high dose of the beta-agonist isoproterenol and compared to baseline condition. The robustness of our data is supported by high trait heritabilities (typically H(2)>0.7) and significant correlations of trait values measured in baseline condition with independent multistrain datasets of the Mouse Phenome Database. We then focused on the drug-, dose-, and strain-specific responses to beta-stimulation and beta-blockade of a selection of traits including heart rate, systolic blood pressure, cardiac weight indices, ECG parameters and body weight. Because of the wealth of data accumulated, we applied integrative analyses such as comprehensive bi-clustering to investigate the structure of the response across the different phenotypes, strains and experimental conditions. Information extracted from these analyses is discussed in terms of novelty and biological implications. For example, we observe that traits related to ventricular weight in most strains respond only to the high dose of isoproterenol, while heart rate and atrial weight are already affected by the low dose. Finally, we observe little concordance between strain similarity based on the phenotypes and genotypic relatedness computed from genomic SNP profiles. This indicates that cardiovascular phenotypes are unlikely to segregate according to global phylogeny, but rather be governed by smaller, local differences in the genetic architecture of the various strains.

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Although the effects of quality management on social work are still widely unexplored, critics suspect that it will lead to a negative standardization of working conditions, whereas supporters of quality management hope for a greater transparency and effectiveness of service delivery. This article reports on a survey of 30 managers, 261 professionals, and 435 families in 30 family intervention service organizations. It uses cluster analysis to explore the relationship between quality management and different forms of work formalization. Results showed that working conditions generally are enabling for professional practice, but differences exist between what is called here a managerialist machine bureaucracy, an atomistic professional organization, and a collegiate professional organization.

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Aim: We investigate the response of vegetation composition and plant diversity to increasing land clearance, burning and agriculture at the Mesolithic–Neolithic transition (c. 6400–5000 bc) when first farming was introduced. Location: The Valais, a dry alpine valley in Switzerland. Methods: We combine high-resolution pollen, microscopic charcoal and sedimentological data to reconstruct past vegetation, fire and land use. Pollen evenness, rarefaction-based and accumulation-based palynological richness analyses were used to reconstruct past trends in plant diversity. Results: Our results show that from c. 5500 cal. yr bc, slash-and-burn activities created a more open landscape for agriculture, at the expense of Pinus and Betula forests. Land clearance by slash-and-burn promoted diverse grassland ecosystems, while on the long term it reduced woodland and forest diversity, affecting important tree species such as Ulmus and Tilia. Main conclusions: Understanding the resilience of Alpine ecosystems to past disturbance variability is relevant for future nature conservation plans. Our study suggests that forecasted land abandonment in the Alps will lead to pre-Neolithic conditions, with significant biodiversity losses in abandoned grassland ecosystems. Thus, management measures for biodiversity, such as ecological compensation areas, are needed in agricultural landscapes with a millennial history of human impact, such as the non-boreal European lowlands. Our study supports the hypothesis that species coexistence is maximized at an intermediate level of disturbances. For instance, species richness decreased when fire exceeded the quasi-natural variability observed during the Mesolithic times. Under a more natural disturbance regime, rather closed Pinus sylvestris and mixed oak forests would prevail.

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Mit Hilfe der Daten der Lebensverlaufsstudie des Max-Planck-Instituts für Bildungsforschung gehen die Autoren der Frage nach, welche arbeitsmarktbezogenen und institutionellen Faktoren die Erwerbsbeteiligung von Frauen im Lebenslauf beeinflussen und inwieweit sich für unterschiedliche Geburtenkohorten neue Erwerbsbeteiligungsmuster etablieren. Die zugrundliegenden dynamischen Betrachtungen beziehen die Wirkungen vorausgegangener Ereignisse auf die zukünftigen Verlaufsstrukturen mit ein, berücksichtigen bedeutsame Strukturmerkmale für zentrale Lebensbedingungen und versuchen Interdependenzen verschiedener gesellschaftlicher Bereiche zu integrieren. Das Eintreten von für den Lebens- und Berufsverlauf von Frauen typischen Ereignissen wird mit Survival-Analysen vorausgeschätzt.

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The research on which this text is based has been financially supported by the Berne University Research Foundation (2009–2011) as well as by an Ambizione Research Fellowship of the Swiss National Science Foundation (2012–2014). During my stays in South Africa, the Departments of Anthropology at the University of the Witwatersrand, Johannesburg, and the University of South Africa (UNISA), Pretoria, provided me with welcoming and inspiring research environments. This article benefitted greatly from engaged discussions around its presentation at various occasions, notably our ECAS 2011 panel Transition and Justice: Negotiating the Terms of New Beginnings in Africa, held in Uppsala. I am particularly grateful to my co-convener and co-editor Gerhard Anders as well as Laurens Bakker, Keebet von Benda-Beckmann, Ben Cousins, Julia Eckert, Marion Fresia, Vinodh Jaichand, Steffen Jensen, Tim Kelsall, Hanri Mostert, Johanna Mugler, David O'Kane, Julia Pauli, Mats Utas, Julia Zenker and the anonymous referees of Development and Change for their critical engagements.

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The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD.