499 research outputs found

    The Production and Fate of Volatile Organosulfur Compounds in Sulfidic and Ferruginous Sediment

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    Volatile organic sulfur compounds (VOSCs) link the atmospheric, marine, and terrestrial sulfur cycles in marine and marginal marine environments. Despite the important role VOSCs play in global biogeochemical sulfur cycling, less is known about how the local geochemical conditions influence production and consumption of VOSCs. We present a study of dimethyl sulfide (DMS), methanethiol (MeSH), and dimethylsulfoniopropionate (DMSP) in sulfide-rich (sulfidic) and iron-rich (ferruginous) salt marsh sediment from north Norfolk, UK. Initial results illustrate the importance of minimizing time between sampling in remote field locations and laboratory analysis, due to rapid degradation of VOSCs. With rapid analysis of sediment from different depths, we observe high concentrations of DMS, MeSH, and DMSP, with concentrations in surface sediment an order of magnitude higher than those in previous studies of surface water. We measure systematic differences in the concentration and depth distribution of MeSH and DMS between sediment environments; DMS concentrations are higher in ferruginous sediment, and MeSH concentrations are higher in sulfidic sediment. With repeated measurements over a short time period, we show that the degradation patterns for DMS and MeSH are different in the ferruginous versus sulfidic sediment. We discuss potential biogeochemical interactions that could be driving the observed differences in VOSC dynamics in ferruginous and sulfidic sediment.This work was supported by a Churchill Scholarship to J. V. W., NERC Grant NE/S001352/1 to A.V.T. and J. D. T., NERC Grant NE/K01546X/1 to K. R. R., and NERC Grants NE/P012671/1, NE/N002385/1, and NE/M004449/1 to J. D. T. Initial analyses were supported by ERCStG307582 (CARBONSINK) to A. V. T

    Behavioural signs of pain in cats: an expert consensus

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    To identify where a consensus can be reached between veterinary experts in feline medicine on the core signs sufficient for pain (sufficient to indicate pain when they occur, but not necessarily present in all painful conditions) and necessary for pain (necessary in the presence of pain, but not always indicative of pain). Methods A modified Delphi technique was used, consisting of four rounds of questions and evaluation using nineteen participants during the period December 2014 and May 2015. Agreement was considered to be established when 80% of the experts concurred with the same opinion. Results Twenty-five signs were considered sufficient to indicate pain, but no single sign was considered necessary for it. Discussion Further studies are needed to evaluate the validity of these 25 behavioural signs if a specific pain assessment tool is to be developed that is capable of assessing pain in cats based on observational methods alone. The signs reported here may nonetheless help both vets and owners form an initial evaluation of the pain status of cats in their care

    Extragalactic Radio Continuum Surveys and the Transformation of Radio Astronomy

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    Next-generation radio surveys are about to transform radio astronomy by discovering and studying tens of millions of previously unknown radio sources. These surveys will provide new insights to understand the evolution of galaxies, measuring the evolution of the cosmic star formation rate, and rivalling traditional techniques in the measurement of fundamental cosmological parameters. By observing a new volume of observational parameter space, they are also likely to discover unexpected new phenomena. This review traces the evolution of extragalactic radio continuum surveys from the earliest days of radio astronomy to the present, and identifies the challenges that must be overcome to achieve this transformational change.Comment: To be published in Nature Astronomy 18 Sept 201

    A prospective study of postmenopausal hormone use and ovarian cancer risk

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    The relationship between postmenopausal hormone use (PMH) and ovarian cancer risk is unclear, particularly for specific hormone formulations, but recent studies suggest that there is a positive association. We conducted a prospective observational study with 82 905 postmenopausal women, including 389 ovarian cancers, in the Nurses' Health Study from 1976 to 2002. Compared with never users of PMH, both current and past users of ⩾5 years had a significantly elevated risk of ovarian cancer (RR=1.41, 95% confidence interval (CI) 1.07–1.86 and relative risk (RR)=1.52, 95% CI 1.01–2.27, respectively). Examined by hormone type in continuous years, use of unopposed estrogen was associated with a significant increase in the risk of epithelial ovarian cancer (P for trend <0.001; RR for 5-year increment of use=1.25, 95% CI 1.12–1.38). Use of estrogen plus progestin (RR for 5-year increment of use=1.04, 95% CI 0.82–1.32) was not significantly associated with ovarian cancer risk. Generally, results were similar for serous tumours (RR for 5-year increment of unopposed estrogen use=1.23, 95% CI 1.07–1.40) and slightly stronger for endometrioid tumours (RR for 5-year increment of unopposed estrogen use=1.53, 95% CI 1.20–1.94). Recency of use was not significantly associated with ovarian cancer risk, but statistical power was limited here

    Rapid translocation of nanoparticles from the lung airspaces to the body

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    Nano-size particles show promise for pulmonary drug delivery, yet their behavior after deposition in the lung remains poorly understood. In this study, a series of near-infrared (NIR) fluorescent nanoparticles were systematically varied in chemical composition, shape, size and surface charge, and their biodistribution and elimination were quantified in rat models after lung instillation. We demonstrate that nanoparticles with hydrodynamic diameter (HD) less than ≈34 nm and a noncationic surface charge translocate rapidly from the lung to mediastinal lymph nodes. Nanoparticles of HD < 6 nm can traffic rapidly from the lungs to lymph nodes and the bloodstream, and then be subsequently cleared by the kidneys. We discuss the importance of these findings for drug delivery, air pollution and carcinogenesis

    African herbal medicines in the treatment of HIV: Hypoxis and Sutherlandia. An overview of evidence and pharmacology

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    In Africa, herbal medicines are often used as primary treatment for HIV/AIDS and for HIV-related problems. In general, traditional medicines are not well researched, and are poorly regulated. We review the evidence and safety concerns related to the use of two specific African herbals, which are currently recommended by the Ministry of Health in South Africa and member states for use in HIV: African Potato and Sutherlandia. We review the pharmacology, toxicology and pharmacokinetics of these herbal medicines. Despite the popularity of their use and the support of Ministries of Health and NGOs in some African countries, no clinical trials of efficacy exist, and low-level evidence of harm identifies the potential for drug interactions with antiretroviral drugs. Efforts should be made by mainstream health professionals to provide validated information to traditional healers and patients on the judicious use of herbal remedies. This may reduce harm through failed expectations, pharmacologic adverse events including possible drug/herb interactions and unnecessary added therapeutic costs. Efforts should also be directed at evaluating the possible benefits of natural products in HIV/AIDS treatment

    Quantitative RT-PCR analysis of differentially expressed genes in Quercus suber in response to Phytophthora cinnamomi infection

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    cDNA-AFLP methodology was used to gain insight into gene fragments differentially present in the mRNA profiles of Quercus suber roots infected with zoospores of Phytophthora cinnamomi at different post challenge time points. Fifty-three transcript-derived fragments (TDFs) were identified and sequenced. Six candidate genes were selected based on their expression patterns and homology to genes known to play a role in defence. They encode a cinnamyl alcohol dehydrogenase2 (QsCAD2), a protein disulphide isomerase (QsPDI), a CC-NBS-LRR resistance protein (QsRPc), a thaumatin-like protein (QsTLP), a chitinase (QsCHI) and a 1,3-β-glucanase (QsGlu). Evaluation of the expression of these genes by quantitative polymerase chain reaction (qPCR) revealed that transcript levels of QsRPc, QsCHI, QsCAD2 and QsPDI increased during the first 24 h post-inoculation, while those of thaumatin-like protein decreased. No differential expression was observed for 1,3-β-glucanase (QsGlu).Four candidate reference genes, polymerase II (QsRPII), eukaryotic translation initiation factor 5A (QsEIF-5A), β-tubulin (QsTUB) and a medium subunit family protein of clathrin adaptor complexes (QsCACs) were assessed to determine the most stable internal references for qRT-PCR normalization in the Phytophthora-Q. suber pathosystem in root tissues. Those found to be more stable, QsRPII and QsCACs, were used as internal reference in the present work.Knowledge on the Quercus defence mechanisms against biotic stress is scarce. This study provides an insight into the gene profiling of a few important genes of Q. suber in response to P. cinnamomi infection contributing to the knowledge of the molecular interactions involving Quercus and root pathogens that can be useful in the future to understand the mechanisms underlying oak resistance to soil-borne oomycetes.Peer Reviewe

    Antigen-Specific IgG ameliorates allergic airway inflammation via Fcγ receptor IIB on dendritic cells

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    <p>Abstract</p> <p>Background</p> <p>There have been few reports on the role of Fc receptors (FcRs) and immunoglobulin G (IgG) in asthma. The purpose of this study is to clarify the role of inhibitory FcRs and antigen presenting cells (APCs) in pathogenesis of asthma and to evaluate antigen-transporting and presenting capacity by APCs in the tracheobronchial mucosa.</p> <p>Methods</p> <p>In FcγRIIB deficient (KO) and C57BL/6 (WT) mice, the effects of intratracheal instillation of antigen-specific IgG were analysed using the model with sensitization and airborne challenge with ovalbumin (OVA). Thoracic lymph nodes instilled with fluorescein-conjugated OVA were analysed by fluorescence microscopy. Moreover, we analysed the CD11c<sup>+ </sup>MHC class II<sup>+ </sup>cells which intaken fluorescein-conjugated OVA in thoracic lymph nodes by flow cytometry. Also, lung-derived CD11c<sup>+ </sup>APCs were analysed by flow cytometry. Effects of anti-OVA IgG1 on bone marrow dendritic cells (BMDCs) <it>in vitro </it>were also analysed. Moreover, in FcγRIIB KO mice intravenously transplanted dendritic cells (DCs) differentiated from BMDCs of WT mice, the effects of intratracheal instillation of anti-OVA IgG were evaluated by bronchoalveolar lavage (BAL).</p> <p>Results</p> <p>In WT mice, total cells and eosinophils in BAL fluid reduced after instillation with anti-OVA IgG1. Anti-OVA IgG1 suppressed airway inflammation in hyperresponsiveness and histology. In addition, the number of the fluorescein-conjugated OVA in CD11c<sup>+ </sup>MHC class II<sup>+ </sup>cells of thoracic lymph nodes with anti-OVA IgG1 instillation decreased compared with PBS. Also, MHC class II expression on lung-derived CD11c<sup>+ </sup>APCs with anti-OVA IgG1 instillation reduced. Moreover, in vitro, we showed that BMDCs with anti-OVA IgG1 significantly decreased the T cell proliferation. Finally, we demonstrated that the lacking effects of anti-OVA IgG1 on airway inflammation on FcγRIIB KO mice were restored with WT-derived BMDCs transplanted intravenously.</p> <p>Conclusion</p> <p>Antigen-specific IgG ameliorates allergic airway inflammation via FcγRIIB on DCs.</p

    A Comprehensive Map of Mobile Element Insertion Polymorphisms in Humans

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    As a consequence of the accumulation of insertion events over evolutionary time, mobile elements now comprise nearly half of the human genome. The Alu, L1, and SVA mobile element families are still duplicating, generating variation between individual genomes. Mobile element insertions (MEI) have been identified as causes for genetic diseases, including hemophilia, neurofibromatosis, and various cancers. Here we present a comprehensive map of 7,380 MEI polymorphisms from the 1000 Genomes Project whole-genome sequencing data of 185 samples in three major populations detected with two detection methods. This catalog enables us to systematically study mutation rates, population segregation, genomic distribution, and functional properties of MEI polymorphisms and to compare MEI to SNP variation from the same individuals. Population allele frequencies of MEI and SNPs are described, broadly, by the same neutral ancestral processes despite vastly different mutation mechanisms and rates, except in coding regions where MEI are virtually absent, presumably due to strong negative selection. A direct comparison of MEI and SNP diversity levels suggests a differential mobile element insertion rate among populations

    MTHFR C677T and MTR A2756G polymorphisms and the homocysteine lowering efficacy of different doses of folic acid in hypertensive Chinese adults

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    <p>Abstract</p> <p>Background</p> <p>This study aimed to investigate if the homocysteine-lowering efficacy of two commonly used physiological doses (0.4 mg/d and 0.8 mg/d) of folic acid (FA) can be modified by individual methylenetetrahydrofolate reductase (MTHFR) C677T and/or methionine synthase (MTR) A2756G polymorphisms in hypertensive Chinese adults.</p> <p>Methods</p> <p>A total of 480 subjects with mild or moderate essential hypertension were randomly assigned to three treatment groups: 1) enalapril only (10 mg, control group); 2) enalapril-FA tablet [10:0.4 mg (10 mg enalapril combined with 0.4 mg of FA), low FA group]; and 3) enalapril-FA tablet (10:0.8 mg, high FA group), once daily for 8 weeks.</p> <p>Results</p> <p>After 4 or 8 weeks of treatment, homocysteine concentrations were reduced across all genotypes and FA dosage groups, except in subjects with MTR 2756AG /GG genotype in the low FA group at week 4. However, compared to subjects with MTHFR 677CC genotype, homocysteine concentrations remained higher in subjects with CT or TT genotype in the low FA group (<it>P </it>< 0.05 for either of these genotypes) and TT genotype in the high FA group (<it>P </it>< 0.05). Furthermore, subjects with TT genotype showed a greater homocysteine-lowering response than did subjects with CC genotype in the high FA group (mean percent reduction of homocysteine at week 8: CC 10.8% vs. TT: 22.0%, <it>P </it>= 0.005), but not in the low FA group (CC 9.9% vs. TT 11.2%, <it>P </it>= 0.989).</p> <p>Conclusions</p> <p>This study demonstrated that MTHFR C677T polymorphism can not only affect homocysteine concentration at baseline and post-FA treatment, but also can modify therapeutic responses to various dosages of FA supplementation.</p
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