322 research outputs found

    A companion to a quasar at redshift 4.7

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    There is a growing consensus that the emergence of quasars at high redshifts is related to the onset of galaxy formation, suggesting that the detection of concentrations of gas accompanying such quasars should provide clues about the early history of galaxies. Quasar companions have been recently identified at redshifts up to z≈3z \approx 3. Here we report observations of Lyman-α\alpha emission (a tracer of ionised hydrogen) from the companion to a quasar at zz=4.702, corresponding to a time when the Universe was less than ten per cent of its present age. We argue that most of the emission arises in a gaseous nebula that has been photoionised by the quasar, but an additional component of continuum light -perhaps quasar light scattered from dust in the companion body, or emission from young stars within the nebula- appears necessary to explain the observations. These observations may be indicative of the first stages in the assembly of galaxy-sized structures.Comment: 8 pages, 4 figures, plain LaTeX. Accepted for publication in Natur

    Autopsy as an outcome and performance measure: three years of hospital autopsy as an instrument of clinical audit

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    An extensive literature documents a high prevalence of errors in clinical diagnosis discovered at autopsy. Multiple studies have suggested no significant decrease in these errors over time. Despite these findings, autopsies have dramatically decreased in frequency in the United States and many other countries. In 1994, the last year for which national U.S. data exist, the autopsy rate for all non-forensic deaths fell below 6%. The marked decline in autopsy rates from previous rates of 40\u201350% undoubtedly reflects various factors, including reimbursement issues, the attitudes of clinicians regarding the utility of autopsies in the setting of other diagnostic advances, and general unfamiliarity with the autopsy and techniques for requesting it, especially among physicians-in-training. The autopsy is valuable for its role in undergraduate and graduate medical education, the identification and characterization of new diseases, and contributions to the understanding of disease pathogenesis. Although extensive, these benefits are difficult to quantify. This review of the last three years of hospital autopsy in Lucca studied the more easily quantifiable benefits of the autopsy as a tool in performance measurement and improvement. Such benefits largely relate to the role of the autopsy in detecting errors in clinical diagnosis and unsuspected complications of treatment. It is hoped that characterizing the extent to which the autopsy provides data relevant to clinical performance measurement and improvement will help inform strategies for preserving the benefits of routinely obtained autopsies and for considering its wider use as an instrument for quality improvement

    Examen médical des personnes victimes de violence : fréquence des facteurs aggravants au sens du Code pénal, hétérogénéité des pratiques

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    Objectifs En cas de violences volontaires, le Code pénal reconnaît l’existence de facteurs aggravants. Aucune donnée n’est disponible sur la fréquence des facteurs aggravants lors des situations de violence. L’objectif principal était de déterminer cette fréquence. L’objectif secondaire était de préciser les résultats de la détermination d’incapacité totale de travail (ITT) dans plusieurs consultations médico-judiciaires en France. Méthodes Le recueil de données prospectif porte sur six centres et 300 situations de violence. Les éléments recueillis concernaient l’existence de facteurs aggravants, les caractéristiques de la victime et des violences, les résultats de l’examen médical et les facteurs intervenus dans la détermination de l’ITT. Résultats Il existait un facteur aggravant dans 232 cas sur 300, 77 %. La durée médiane d’ITT était de deux jours (extrêmes : 0–60). La fréquence des cas sans ITT était comprise entre 0 et 56 % selon les centres (Chi2, p < 0,0001). Les médecins examinateurs considéraient ne pas avoir évalué l’état psychique dans 63 cas (21 %), d’importantes différences étant observées selon les centres (p < 0,0001). L’ITT était surtout fondée sur des éléments lésionnels dans 45 % des cas et sur des éléments fonctionnels dans 55 % des cas, cette répartition variant selon les centres (p = 0,01). L’état psychique était prépondérant dans la détermination de l’ITT dans 0 à 23 % des cas selon les centres (p = 0,009)

    A pilot feasibility trial of alcohol screening and brief intervention in the police custody setting (ACCEPT): study protocol for a cluster randomised controlled trial

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    BACKGROUND: There is evidence of an association between alcohol use and offending behaviour and around a quarter of police time is spent on alcohol-related incidents. Police custody, therefore, provides an important opportunity to intervene. This pilot trial aims to investigate whether a definitive evaluation of screening and brief interventions aimed at reducing risky drinking in arrestees is acceptable and feasible in the custody suite setting. METHODS: Screening will be carried out by trained detention officers or drug and alcohol workers in four police forces across two geographical areas (North East and South West England). Detention officers (or drug and alcohol workers) will be cluster randomised to one of three conditions: screening only (control group), screening followed immediately by 10 min of manualised brief structured advice delivered by the individual responsible for screening (intervention 1) or screening followed by 10 min of manualised brief structured advice delivered by the individual responsible for screening plus the offer of a subsequent 20-min session of behaviour change counselling delivered by a trained alcohol health worker (intervention 2). Participants will be arrestees aged 18+ who screen positive on the Alcohol Use Disorders Identification Test. Participants will be followed up at 6 and 12 months post-intervention. An embedded qualitative process evaluation will explore acceptability of alcohol screening and brief intervention to staff and arrestees as well as facilitators and barriers to the delivery of such approaches in this setting. RESULTS: Recruitment is currently underway and due to end May 2015. CONCLUSION: Results from this pilot trial will determine if a definitive evaluation is possible in the future and will provide stakeholder input to its design. TRIAL REGISTRATION: Reference number: ISRCTN89291046

    Understanding the importance of selenium and selenoproteins in muscle function

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    Selenium is an essential trace element. In cattle, selenium deficiency causes dysfunction of various organs, including skeletal and cardiac muscles. In humans as well, lack of selenium is associated with many disorders, but despite accumulation of clinical reports, muscle diseases are not generally considered on the list. The goal of this review is to establish the connection between clinical observations and the most recent advances obtained in selenium biology. Recent results about a possible role of selenium-containing proteins in muscle formation and repair have been collected. Selenoprotein N is the first selenoprotein linked to genetic disorders consisting of different forms of congenital muscular dystrophies. Understanding the muscle disorders associated with selenium deficiency or selenoprotein N dysfunction is an essential step in defining the causes of the disease and obtaining a better comprehension of the mechanisms involved in muscle formation and maintenance

    Polymorphisms in the Mitochondrial Ribosome Recycling Factor EF-G2mt/MEF2 Compromise Cell Respiratory Function and Increase Atorvastatin Toxicity

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    Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial ribosome recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphisms (SNPs) in the EF-G2mt gene, were generated in the yeast MEF2 gene. Although these mutations do not produce an obvious growth phenotype, three mutations reveal an atorvastatin-sensitive phenotype and further analysis uncovers a decreased respiratory capacity. These findings constitute the first reported phenotype associated with SNPs in the EF-G2mt gene and implicate the human EF-G2mt gene as a pharmacogenetic candidate gene for statin toxicity in humans

    Can we use atmospheric CO<sub>2</sub> measurements to verify emission trends reported by cities? Lessons from a 6-year atmospheric inversion over Paris

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    Existing CO2 emissions reported by city inventories usually lag in real-time by a year or more and are prone to large uncertainties. This study responds to the growing need for timely and precise estimation of urban CO2 emissions to support present and future mitigation measures and policies. We focus on the Paris metropolitan area, the largest urban region in the European Union and the city with the densest atmospheric CO2 observation network in Europe. We performed long-term atmospheric inversions to quantify the citywide CO2 emissions, i.e., fossil fuel as well as biogenic sources and sinks, over 6 years (2016–2021) using a Bayesian inverse modeling system. Our inversion framework benefits from a novel near-real-time hourly fossil fuel CO2 emission inventory (Origins.earth) at 1 km spatial resolution. In addition to the mid-afternoon observations, we attempt to assimilate morning CO2 concentrations based on the ability of the Weather Research and Forecasting model with Chemistry (WRF-Chem) transport model to simulate atmospheric boundary layer dynamics constrained by observed layer heights. Our results show a long-term decreasing trend of around 2 % ± 0.6 % per year in annual CO2 emissions over the Paris region. The impact of the COVID-19 pandemic led to a 13 % ± 1 % reduction in annual fossil fuel CO2 emissions in 2020 with respect to 2019. Subsequently, annual emissions increased by 5.2 % ± 14.2 % from 32.6 ± 2.2 Mt CO2 in 2020 to 34.3 ± 2.3 Mt CO2 in 2021. Based on a combination of up-to-date inventories, high-resolution atmospheric modeling and high-precision observations, our current capacity can deliver near-real-time CO2 emission estimates at the city scale in less than a month, and the results agree within 10 % with independent estimates from multiple city-scale inventories.</p

    Deregulated expression of TANK in glioblastomas triggers pro-tumorigenic ERK1/2 and AKT signaling pathways

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    Signal transmission by the noncanonical IkappaB kinases (IKKs), TANK-binding kinase 1 (TBK1) and IKKɛ, requires interaction with adapter proteins such as TRAF associated NF-κB activator (TANK). Although increased expression or dysregulation of both kinases has been described for a variety of human cancers, this study shows that deregulated expression of the TANK protein is frequently occurring in glioblastomas (GBMs). The functional relevance of TANK was analyzed in a panel of GBM-derived cell lines and revealed that knockdown of TANK arrests cells in the S-phase and prohibits tumor cell migration. Deregulated TANK expression affects several signaling pathways controlling cell proliferation and the inflammatory response. Interference with stoichiometrically assembled signaling complexes by overexpression or silencing of TANK prevented constitutive interferon-regulatory factor 3 (IRF3) phosphorylation. Knockdown of TANK frequently prevents constitutive activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2). TANK-mediated ERK1/2 activation is independent from the canonical MAP kinase or ERK kinase (MEK) 1/2-mediated pathway and utilizes an alternative pathway that uses a TBK1/IKKɛ/Akt signaling axis, thus identifying a novel pathway suitable to block constitutive ERK1/2 activity.Peer reviewe

    The prosurvival IKK-related kinase IKKϵ integrates LPS and IL17A signaling cascades to promote Wnt-dependent tumor development in the intestine

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    Constitutive Wnt signaling promotes intestinal cell proliferation, but signals from the tumor microenvironment are also required to support cancer development. The role that signaling proteins play to establish a tumor microenvironment has not been extensively studied. Therefore, we assessed the role of the proinflammatory Ikk-related kinase Ikkϵ in Wnt-driven tumor development. We found that Ikkϵ was activated in intestinal tumors forming upon loss of the tumor suppressor Apc. Genetic ablation of Ikkϵ in b-catenin-driven models of intestinal cancer reduced tumor incidence and consequently extended survival. Mechanistically, we attributed the tumor-promoting effects of Ikkϵ to limited TNF-dependent apoptosis in transformed intestinal epithelial cells. In addition, Ikkϵ was also required for lipopolysaccharide (LPS) and IL17A-induced activation of Akt, Mek1/2, Erk1/2, and Msk1. Accordingly, genes encoding proinflammatory cytokines, chemokines, and anti-microbial peptides were downregulated in Ikkϵ-deficient tissues, subsequently affecting the recruitment of tumor-associated macrophages and IL17A synthesis. Further studies revealed that IL17A synergized with commensal bacteria to trigger Ikkϵ phosphorylation in transformed intestinal epithelial cells, establishing a positive feedback loop to support tumor development. Therefore, TNF, LPS, and IL17A-dependent signaling pathways converge on Ikkϵ to promote cell survival and to establish an inflammatory tumor microenvironment in the intestine upon constitutive Wnt activation. � 2016 American Association for Cancer Research
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