1,253 research outputs found

    Redox-Mediated Inactivation of the Transcriptional Repressor RcrR is Responsible for Uropathogenic Escherichia coli's Increased Resistance to Reactive Chlorine Species

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    The ability to overcome stressful environments is critical for pathogen survival in the host. One challenge for bacteria is the exposure to reactive chlorine species (RCS), which are generated by innate immune cells as a critical part of the oxidative burst. Hypochlorous acid (HOCl) is the most potent antimicrobial RCS and is associated with extensive macromolecular damage in the phagocytized pathogen. However, bacteria have evolved defense strategies to alleviate the effects of HOCl-mediated damage. Among these are RCS-sensing transcriptional regulators that control the expression of HOCl-protective genes under non-stress and HOCl stress. Uropathogenic Escherichia coli (UPEC), the major causative agent of urinary tract infections (UTIs), is particularly exposed to infiltrating neutrophils during pathogenesis; however, their responses to and defenses from HOCl are still completely unexplored. Here, we present evidence that UPEC strains tolerate higher levels of HOCl and are better protected from neutrophil-mediated killing compared with other E. coli. Transcriptomic analysis of HOCl-stressed UPEC revealed the upregulation of an operon consisting of three genes, one of which encodes the transcriptional regulator RcrR. We identified RcrR as a HOCl-responsive transcriptional repressor, which, under non-stress conditions, is bound to the operator and represses the expression of its target genes. During HOCl exposure, however, the repressor forms reversible intermolecular disulfide bonds and dissociates from the DNA resulting in the derepression of the operon. Deletion of one of the target genes renders UPEC significantly more susceptible to HOCl and phagocytosis indicating that the HOCl-mediated induction of the regulon plays a major role for UPEC’s HOCl resistance

    The association between weekly hours of physical activity and mental health: A three-year follow-up study of 15–16-year-old students in the city of Oslo, Norway

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    <p>Abstract</p> <p>Background</p> <p>Mental health problems are a worldwide public health burden. The literature concerning the mental health benefits from physical activity among adults has grown. Adolescents are less studied, and especially longitudinal studies are lacking. This paper investigates the associations between weekly hours of physical activity at age 15–16 and mental health three years later.</p> <p>Methods</p> <p>Longitudinal self-reported health survey. The baseline study consisted of participants from the youth section of the Oslo Health Study, carried out in schools in 2000–2001 (<it>n </it>= 3811). The follow-up in 2003–2004 was conducted partly at school and partly through mail. A total of 2489 (1112 boys and 1377 girls) participated in the follow-up. Mental health was measured by the Strengths and Difficulties Questionnaire with an impact supplement. Physical activity was measured by a question on weekly hours of physical activity outside of school, defined as exertion 'to an extent that made you sweat and/or out of breath'. Adjustments were made for well-documented confounders and mental health at baseline.</p> <p>Results</p> <p>In boys, the number of hours spent on physical activity per week at age 15–16 was negatively associated with emotional symptoms [B (95%CI) = -0.09 (-0.15, -0.03)] and peer problems [B (95%CI) = -0.08 (-0.14, -0.03)] at age 18–19 after adjustments. In girls, there were no significant differences in SDQ subscales at age 18–19 according to weekly hours of physical activity at age 15–16 after adjustments. Boys and girls with five to seven hours of physical activity per week at age 15–16 had the lowest mean scores for total difficulties and the lowest percentage with high impact score at age 18–19, but the differences were not statistically significant after adjustments.</p> <p>Conclusion</p> <p>Weekly hours of physical activity at age 15–16 years was weakly associated with mental health at three-year follow-up in boys. Results encourage a search for further knowledge about physical activity as a possible protective factor in relation to mental health problems in adolescence.</p

    Increased Throughput by Parallelization of Library Preparation for Massive Sequencing

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    Background: Massively parallel sequencing systems continue to improve on data output, while leaving labor-intensive library preparations a potential bottleneck. Efforts are currently under way to relieve the crucial and time-consuming work to prepare DNA for high-throughput sequencing. Methodology/Principal Findings: In this study, we demonstrate an automated parallel library preparation protocol using generic carboxylic acid-coated superparamagnetic beads and polyethylene glycol precipitation as a reproducible and flexible method for DNA fragment length separation. With this approach the library preparation for DNA sequencing can easily be adjusted to a desired fragment length. The automated protocol, here demonstrated using the GS FLX Titanium instrument, was compared to the standard manual library preparation, showing higher yield, throughput and great reproducibility. In addition, 12 libraries were prepared and uniquely tagged in parallel, and the distribution of sequence reads between these indexed samples could be improved using quantitative PCR-assisted pooling. Conclusions/Significance: We present a novel automated procedure that makes it possible to prepare 36 indexed libraries per person and day, which can be increased to up to 96 libraries processed simultaneously. The yield, speed and robust performance of the protocol constitute a substantial improvement to present manual methods, without the need of extensive equipment investments. The described procedure enables a considerable efficiency increase for small to midsiz

    A randomized controlled trial to investigate the influence of low dose radiotherapy on immune stimulatory effects in liver metastases of colorectal cancer

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    <p>Abstract</p> <p>Background</p> <p>Insufficient migration and activation of tumor specific effector T cells in the tumor is one of the main reasons for inadequate host anti-tumor immune response. External radiation seems to induce inflammation and activate the immune response. This phase I/II clinical trial aims to evaluate whether low dose single fraction radiotherapy can improve T cell associated antitumor immune response in patients with colorectal liver metastases.</p> <p>Methods/Design</p> <p>This is an investigator-initiated, prospective randomised, 4-armed, controlled Phase I/II trial. Patients undergoing elective hepatic resection due to colorectal cancer liver metastasis will be enrolled in the study. Patients will receive 0 Gy, 0.5 Gy, 2 Gy or 5 Gy radiation targeted to their liver metastasis. Radiation will be applied by external beam radiotherapy using a 6 MV linear accelerator (Linac) with intensity modulated radiotherapy (IMRT) technique two days prior to surgical resection. All patients admitted to the Department of General-, Visceral-, and Transplantion Surgery, University of Heidelberg for elective hepatic resection are consecutively screened for eligibility into this trial, and written informed consent is obtained before inclusion. The primary objective is to assess the effect of active local external beam radiation dose on, tumor infiltrating T cells as a surrogate parameter for antitumor activity. Secondary objectives include radiogenic treatment toxicity, postoperative morbidity and mortality, local tumor control and recurrence patterns, survival and quality of life. Furthermore, frequencies of systemic tumor reactive T cells in blood and bone marrow will be correlated with clinical outcome.</p> <p>Discussion</p> <p>This is a randomized controlled patient blinded trial to assess the safety and efficiency of low dose radiotherapy on metastasis infiltrating T cells and thus potentially enhance the antitumor immune response.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01191632">NCT01191632</a></p

    Image informatics strategies for deciphering neuronal network connectivity

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    Brain function relies on an intricate network of highly dynamic neuronal connections that rewires dramatically under the impulse of various external cues and pathological conditions. Among the neuronal structures that show morphologi- cal plasticity are neurites, synapses, dendritic spines and even nuclei. This structural remodelling is directly connected with functional changes such as intercellular com- munication and the associated calcium-bursting behaviour. In vitro cultured neu- ronal networks are valuable models for studying these morpho-functional changes. Owing to the automation and standardisation of both image acquisition and image analysis, it has become possible to extract statistically relevant readout from such networks. Here, we focus on the current state-of-the-art in image informatics that enables quantitative microscopic interrogation of neuronal networks. We describe the major correlates of neuronal connectivity and present workflows for analysing them. Finally, we provide an outlook on the challenges that remain to be addressed, and discuss how imaging algorithms can be extended beyond in vitro imaging studies

    Analysis of the anti-tumor effect of cetuximab using protein kinetics and mouse xenograft models

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    <p>Abstract</p> <p>Background</p> <p>The binding of EGFR and its ligands leads to autophosphorylation of receptor tyrosine kinase as well as subsequent activation of signal transduction pathways that are involved in regulating cellular proliferation, differentiation, and survival. An EGFR inhibitor, cetuximab binds to EGFR and consequently blocks a variety of cellular processes. <it>KRAS</it>/<it>BRAF </it>mutations are known to be associated with a low response rate to cetuximab. In the present study, to clarify the anti-tumor mechanisms of cetuximab, we evaluated the <it>KRAS</it>/<it>BRAF </it>status, phosphorylation level of the EGFR pathway, and the tumor suppression effect in vivo, using a human colon cancer cell line HT29, which exhibited the highest EGFR expression in response to the cetuximab therapy among the 6 colorectal cancer cell lines tested.</p> <p>Findings</p> <p>The conventional growth suppression assay did not work efficiently with cetuximab. EGF, TGF-α, and IGF activated the EGFR/MAPK cell signaling pathway by initiating the phosphorylation of EGFR. Cetuximab partially inhibited the EGFR/MAPK pathway induced by EGF, TGF-α, and IGF. However, cetuximab exposure induced the EGFR, MEK, and ERK1/2 phosphorylation by itself. Mouse xenograft tumor growth was significantly inhibited by cetuximab and both cetuximab-treated and -untreated xenograft specimens exhibited phosphorylations of the EGFR pathway proteins.</p> <p>Conclusions</p> <p>We have confirmed that cetuximab inhibited the EGFR/MAPK pathway and reduced tumor growth in the xenografts while the remaining tumor showed EGFR pathway activation. These results suggest that: ( i ) The effect of cetuximab in growth signaling is not sufficient to induce complete growth suppression in vitro; ( ii ) time-course monitoring may be necessary to evaluate the effect of cetuximab because EGFR signaling is transmitted in a minute order; and ( iii ) cetuximab treatment may have cells acquired resistant selectively survived in the heterogeneous cancer population.</p

    Monitoring activities of teenagers to comprehend their habits: study protocol for a mixed-methods cohort study

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    Abstract: Background: Efforts to increase physical activity in youth need to consider which activities are most likely to be sustained over time in order to promote lifelong participation in physical activity. The Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study is a prospective cohort study that uses quantitative and qualitative methods to develop new knowledge on the sustainability of specific physical activities. Methods/design: Eight hundred and forty-three grade 5 and 6 students recruited from 17 elementary schools in New Brunswick, Canada, are followed-up three times per year. At each survey cycle, participants complete self-report questionnaires in their classroom under the supervision of trained data collectors. A sub-sample of 24 physically active students is interviewed annually using a semi-structured interview protocol. Parents (or guardians) complete telephone administered questionnaires every two years, and a health and wellness school audit is completed for each school. Discussion: MATCH will provide a description of the patterns of participation in specific physical activities in youth, and enable identification of the determinants of maintenance, decline, and uptake of participation in each activity. These data will inform the development of interventions that take into account which activities are the most likely to be maintained and why activities are maintained or dropped

    Measurement of the branching fraction and CP content for the decay B(0) -> D(*+)D(*-)

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    This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APS.We report a measurement of the branching fraction of the decay B0→D*+D*- and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4  fb-1 collected at the Υ(4S) resonance during 1999–2000, we have reconstructed 38 candidate signal events in the mode B0→D*+D*- with an estimated background of 6.2±0.5 events. From these events, we determine the branching fraction to be B(B0→D*+D*-)=[8.3±1.6(stat)±1.2(syst)]×10-4. The measured CP-odd fraction of the final state is 0.22±0.18(stat)±0.03(syst).This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A.P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation

    Smoke rings:towards a comprehensive tobacco free policy for the Olympic Games

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    Background The tobacco industry has long sought affiliation with major sporting events, including the Olympic Games, for marketing, advertising and promotion purposes. Since 1988, each Olympic Games has adopted a tobacco-free policy. Limited study of the effectiveness of the smoke-free policy has been undertaken to date, with none examining the tobacco industry's involvement with the Olympics or use of the Olympic brand. Methods and Findings A comparison of the contents of Olympic tobacco-free policies from 1988 to 2014 was carried out by searching the websites of the IOC and host NOCs. The specific tobacco control measures adopted for each Games were compiled and compared with measures recommended by the WHO Tobacco Free Sports Initiative and Article 13 of the Framework Convention on Tobacco Control (FCTC). This was supported by semi-structured interviews of key informants involved with the adoption of tobacco-free policies for selected games. To understand the industry's interests in the Olympics, the Legacy Tobacco Documents Library (http://legacy.library.ucsf.edu) was systematically searched between June 2013 and August 2014. Company websites, secondary sources and media reports were also searched to triangulate the above data sources. This paper finds that, while most direct associations between tobacco and the Olympics have been prohibited since 1988, a variety of indirect associations undermine the Olympic tobacco-free policy. This is due to variation in the scope of tobacco-free policies, limited jurisdiction and continued efforts by the industry to be associated with Olympic ideals. Conclusions The paper concludes that, compatible with the IOC's commitment to promoting healthy lifestyles, a comprehensive tobacco-free policy with standardized and binding measures should be adopted by the International Olympic Committee and all national Olympic committees
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