196 research outputs found

    Altered visual processing in a rodent model of Attention-Deficit Hyperactivity Disorder

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    A central component of Attention-Deficit Hyperactivity Disorder (ADHD) is increased distractibility, which is linked to the superior colliculus (SC) in a range of species, including humans. Furthermore, there is now mounting evidence of altered collicular functioning in ADHD and it is proposed that a hyper-responsive SC could mediate the main symptoms of ADHD, including distractibility. In the present study we have provided a systematic characterization of the SC in the most commonly used and well-validated animal model of ADHD, the spontaneously hypertensive rat (SHR). We examined collicular-dependent orienting behavior, local field potential (LFP) and multiunit responses to visual stimuli in the anesthetized rat and morphological measures in the SHR in comparison to the Wistar Kyoto (WKY) and Wistar (WIS). We found that SHRs remain responsive to a repeated visual stimulus for more presentations than control strains and have a longer response duration. In addition, LFP and multiunit activity within the visually responsive superficial layers of the SC showed the SHR to have a hyper-responsive SC relative to control strains, which could not be explained by altered functioning of the retinocollicular pathway. Finally, examination of collicular volume, neuron and glia densities and glia:neuron ratio revealed that the SHR had a reduced ratio relative to the WKY which could explain the increased responsiveness. In conclusion, this study demonstrates strain-specific changes in the functioning and structure of the SC in the SHR, providing convergent evidence that the SC might be dysfunctional in ADHD

    Upgrade of the HadGEM3-A based attribution system to high resolution and a new validation framework for probabilistic event attribution

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    We present a substantial upgrade of the Met Office system for the probabilistic attribution of extreme weather and climate events with higher horizontal and vertical resolution (60 km mid-latitudes and 85 vertical levels), the latest Hadley Centre atmospheric and land model (ENDGame dynamics with GA6.0 science and JULES at GL6.0) as well as an updated forcings set. A new set of experiments designed for the evaluation and implementation of an operational attribution service are described which consist of pairs of multi-decadal stochastic physics ensembles continued on a season by season basis by large ensembles that are able to sample extreme at- mospheric states possible in the recent past. Diagnostics from these experiments form the HadGEM3-A contribution to the international Climate of the 20th Century Plus (C20Cþ) project and were analysed under the European Climate and Weather Events: Interpretation and Attribution (EUCLEIA) event attribution project as well as contributing to the Climate Science for Service Partnership (CSSP)-China programme. After discussing the framing issues surrounding questions that can be asked with our system we construct a novel approach to the evaluation of atmosphere-only ensembles intended for event attribution, in the process highlighting and clarifying the distinction between hindcast skill and model performance. A framework based around assessing model representation of predictable components and ensuring exchangeability of model and real world statistics leads to a form of detection and attribution to boundary condition forcing as a means of quantifying one degree of freedom of potential model error and allowing for the bias correction of event probabilities and resulting probability ratios. This method is then applied systematically across the globe to assess contributions from anthropogenic influence and specific boundary conditions to the changing probability of observed and record seasonal mean temperatures of four recent 3-month seasons from March 2016–February 2017

    Increasing precipitation variability on daily-to-multiyear timescales in a warmer world

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    This is the final version. Available on open access from the American Association for the Advancement of Science via the DOI in this recordData and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper, supplementary materials, and/or linked repositories. The GPCP precipitation data is acquired from https://climatedataguide.ucar.edu/climate-data/gpcp-daily-global precipitation-climatology-project. The IMERG precipitation data is acquired from https://gpm.nasa.gov/data/directory. For the HadGEM3-GC3.05 PPE simulations, two-dimensional fields can be accessed from https://catalogue.ceda.ac.uk/uuid/f1a2fc3c120f400396a92f5de84d596a, and post-processed three dimensional fields can be accessed from https://doi.org/10.7910/DVN/GHWGG0.The hydrological cycle intensifies under global warming with precipitation increases. How the increased precipitation varies temporally at a given location has vital implications for regional climates and ecosystem services. Based on ensemble climate model projections under a high emission scenario, here we show that approximately two-thirds of land on Earth will face a “wetter and more variable” hydroclimate on daily to multiyear timescales. This means wider swings between wet and dry extremes. Such an amplification of precipitation variability is particularly prominent over climatologically wet regions, with percentage increases in variability more than twice those in mean precipitation. Thermodynamic effects, linked to increased moisture availability, increase precipitation variability uniformly everywhere. It is the dynamic effects (negative) linked to weakened circulation variability that make precipitation variability changes strongly region dependent. The increase in precipitation variability poses a new challenge to the climate resilience of infrastructures and human society.National Natural Science Foundation of ChinaChina Postdoctoral Science FoundationInternational Partnership Program of Chinese Academy of SciencesUK–China Research Innovation Partnership Fun

    PHL 1445: An eclipsing cataclysmic variable with a substellar donor near the period minimum

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    PublishedThis is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record is available online via the DOI in this record.We present high-speed, three-colour photometry of the eclipsing dwarf nova PHL 1445, which, with an orbital period of 76.3 min, lies just below the period minimum of ~82 min for cataclysmic variable stars (CVs). Averaging four eclipses reveals resolved eclipses of the white dwarf and bright spot. We determined the system parameters by fitting a parametrized eclipse model to the averaged light curve. We obtain a mass ratio of q = 0.087 ± 0.006 and inclination i = 85°.2 ± 0°.9. The primary and donor masses were found to be Mw = 0.73 ± 0.03 M⊙ and Md = 0.064 ± 0.005 M⊙, respectively. Through multicolour photometry a temperature of the white dwarf of Tw = 13 200 ± 700 K and a distance of 220 ± 50 pc were determined. The evolutionary state of PHL 1445 is uncertain. We are able to rule out a significantly evolved donor, but not one that is slightly evolved. Formation with a brown dwarf donor is plausible, though the brown dwarf would need to be no older than 600 Myr at the start of mass transfer, requiring an extremely low mass ratio (q = 0.025) progenitor system. PHL 1445 joins SDSS 1433 as a sub-period minimum CV with a substellar donor. The existence of two such systems raises an alternative possibility that current estimates for the intrinsic scatter and/or position of the period minimum may be in error.UK Science and Technology Facilities Council (STFC)FONDECY

    Specificity of T cells in synovial fluid: high frequencies of CD8(+) T cells that are specific for certain viral epitopes

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    INTRODUCTION: Epstein-Barr virus (EBV) is transmitted orally, replicates in the oropharynx and establishes life-long latency in human B lymphocytes. T-cell responses to latent and lytic/replicative cycle proteins are readily detectable in peripheral blood from healthy EBV-seropositive individuals. EBV has also been detected within synovial tissue, and T-cell responses to EBV lytic proteins have been reported in synovial fluid from a patient with rheumatoid arthritis (RA). This raises the question regarding whether T cells specific for certain viruses might be present at high frequencies within synovial fluid and whether such T cells might be activated or able to secrete cytokines. If so, they might play a 'bystander' role in the pathogenesis of inflammatory joint disease. OBJECTIVES: To quantify and characterize T cells that are specific for epitopes from EBV, cytomegalovirus (CMV) and influenza in peripheral blood and synovial fluid from patients with arthritis. METHODS: Peripheral blood mononuclear cells (PBMCs) and synovial fluid mononuclear cells (SFMCs) were obtained from patients with inflammatory arthritis (including those with RA, osteoarthritis, psoriatic arthritis and reactive arthritis). Samples from human leucocyte antigen (HLA)-A2-positive donors were stained with fluorescent-labelled tetramers of HLA-A2 complexed with the GLCTLVAML peptide epitope from the EBV lytic cycle protein BMLF1, the GILGFVFTL peptide epitope from the influenza A matrix protein, or the NLVPMVATV epitope from the CMV pp65 protein. Samples from HLA-B8-positive donors were stained with fluorescent-labelled tetramers of HLA-B8 complexed with the RAKFKQLL peptide epitope from the EBV lytic protein BZLF1 or the FLRGRAYGL peptide epitope from the EBV latent protein EBNA3A. All samples were costained with an antibody specific for CD8. CD4(+) T cells were not analyzed. Selected samples were costained with antibodies specific for cell-surface glycoproteins, in order to determine the phenotype of the T cells within the joint and the periphery. Functional assays to detect release of IFN-γ or tumour necrosis factor (TNF)-α were also performed on some samples. RESULTS: The first group of 15 patients included 10 patients with RA, one patient with reactive arthritis, one patient with psoriatic arthritis and three patients with osteoarthritis. Of these, 11 were HLA-A2 positive and five were HLA-B8 positive. We used HLA-peptide tetrameric complexes to analyze the frequency of EBV-specific T cells in PBMCs and SFMCs (Figs 1 and 2). Clear enrichment of CD8(+) T cells specific for epitopes from the EBV lytic cycle proteins was seen within synovial fluid from almost all donors studied, including patients with psoriatic arthritis and osteoarthritis and those with RA. In donor RhA6, 9.5% of CD8(+ ) SFMCs were specific for the HLA-A2 restricted GLCTLVAML epitope, compared with 0.5% of CD8(+) PBMCs. Likewise in a donor with osteoarthritis (NR4), 15.5% of CD8(+) SFMCs were specific for the HLA-B8-restricted RAKFKQLL epitope, compared with 0.4% of CD8(+) PBMCs. In contrast, we did not find enrichment of T cells specific for the HLA-B8-restricted FLRGRAYGL epitope (from the latent protein EBNA3A) within SFMCs compared with PBMCs in any donors. In selected individuals we performed ELISpot assays to detect IFN-γ secreted by SFMCs and PBMCs after a short incubation in vitro with peptide epitopes from EBV lytic proteins. These assays confirmed enrichment of T cells specific for epitopes from EBV lytic proteins within synovial fluid and showed that subpopulations of these cells were able to secrete proinflammatory cytokines after short-term stimulation. We used a HLA-A2/GILGFVFTL tetramer to stain PBMCs and SFMCs from six HLA-A2-positive patients. The proportion of T cells specific for this influenza epitope was low (<0.2%) in all donors studied, and we did not find any enrichment within SFMCs. We had access to SFMCs only from a second group of four HLA-A2-positive patients with RA. A tetramer of HLA-A2 complexed to the NLVPMVATV epitope from the CMV pp65 protein reacted with subpopulations of CD8(+) SFMCs in all four donors, with frequencies of 0.2, 0.5, 2.3 and 13.9%. SFMCs from all four donors secreted TNF after short-term incubation with COS cells transfected with HLA-A2 and pp65 complementary DNA. We analyzed the phenotype of virus-specific cells within PBMCs and SFMCs in three donors. The SFMC virus-specific T cells were more highly activated than those in PBMCs, as evidenced by expression of high levels of CD69 and HLA-DR. A greater proportion of SFMCs were CD38(+), CD62L low, CD45RO bright, CD45RA dim, CD57(+) and CD28(-) when compared with PBMCs. DISCUSSION: This work shows that T cells specific for certain epitopes from viral proteins are present at very high frequencies (up to 15.5% of CD8(+) T cells) within SFMCs taken from patients with inflammatory joint disease. This enrichment does not reflect a generalized enrichment for the 'memory pool' of T cells; we did not find enrichment of T cells specific for the GILGFVFTL epitope from influenza A or for the FLRGRAYGL epitope from the EBV latent protein EBNA3A, whereas we found clear enrichment of T cells specific for the GLCTLVAML epitope from the EBV lytic protein BMLF1 and for the RAKFKQLL epitope from the EBV lytic protein BZLF1. The enrichment might reflect preferential recruitment of subpopulations of virus-specific T cells, perhaps based on expression of selectins, chemokine receptors or integrins. Alternatively, T cells specific for certain viral epitopes may be stimulated to proliferate within the joint, by viral antigens themselves or by cross-reactive self-antigens. Finally, it is theoretically possible that subpopulations of T cells within the joint are preferentially protected from apoptotic cell death. Whatever the explanation, the virus-specific T cells are present at high frequency, are activated and are able to secrete proinflammatory cytokines. They could potentially interact with synoviocytes and contribute to the maintenance of inflammation within joints in many different forms of inflammatory arthritis

    Nile red fluorescence screening facilitating neutral lipid phenotype determination in budding yeast, Saccharomyces cerevisiae, and the fission yeast Schizosaccharomyces pombe.

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    Investigation of yeast neutral lipid accumulation is important for biotechnology and also for modelling aberrant lipid metabolism in human disease. The Nile red (NR) method has been extensively utilised to determine lipid phenotypes of yeast cells via microscopic means. NR assays have been used to differentiate lipid accumulation and relative amounts of lipid in oleaginous species but have not been thoroughly validated for phenotype determination arising from genetic modification. A modified NR assay, first described by Sitepu et al. (J Microbiol Methods 91:321-328, 2012), was able to detect neutral lipid changes in Saccharomyces cerevisiae deletion mutants with sensitivity similar to more advanced methodology. We have also be able to, for the first time, successfully apply the NR assay to the well characterised fission yeast Schizosaccharomyces pombe, an increasingly important organism in biotechnology. The described NR fluorescence assay is suitable for increased throughput and rapid screening of genetically modified strains in both the biotechnology industry and for modelling ectopic lipid production for a variety of human diseases. This ultimately negates the need for labour intensive and time consuming lipid analyses of samples that may not yield a desirable lipid phenotype, whilst genetic modifications impacting significantly on the cellular lipid phenotype can be further promoted for more in depth analyses

    Management and treatment of children, young people and adults with systemic lupus erythematosus: British Society for Rheumatology guideline scope

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    \ua9 The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Rheumatology.The objective of this guideline is to provide up-to-date, evidence-based recommendations for the management of SLE that builds upon the existing treatment guideline for adults living with SLE published in 2017. This will incorporate advances in the assessment, diagnosis, monitoring, non-pharmacological and pharmacological management of SLE. General approaches to management as well as organ-specific treatment, including lupus nephritis and cutaneous lupus, will be covered. This will be the first guideline in SLE using a whole life course approach from childhood through adolescence and adulthood. The guideline will be developed with people with SLE as an important target audience in addition to healthcare professionals. It will include guidance related to emerging approved therapies and account for National Institute for Health and Care Excellence Technology Appraisals, National Health Service England clinical commissioning policies and national guidance relevant to SLE. The guideline will be developed using the methods and rigorous processes outlined in ‘Creating Clinical Guidelines: Our Protocol’ by the British Society for Rheumatology

    A study of the impact of individual thermal control on user comfort in the workplace: Norwegian cellular vs. British open plan offices

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    In modern offices, user control is being replaced by centrally operated thermal systems, and in Scandinavia, personal offices by open plan layouts. This study examined the impact of user control on thermal comfort and satisfaction. It compared a workplace, which was designed entirely based on individual control over the thermal environment, to an environment that limited thermal control was provided as a secondary option for fine-tuning: Norwegian cellular and British open plan offices. The Norwegian approach provided each user with control over a window, door, blinds, heating and cooling as the main thermal control system. In contrast, the British practice provided a uniform thermal environment with limited openable windows and blinds to refine the thermal environment for occupants seated around the perimeter of the building. Field studies of thermal comfort were applied to measure users’ perception of thermal environment, empirical building performance and thermal control. The results showed a 30% higher satisfaction and 18% higher comfort level in the Norwegian offices compared to the British practices. However, the energy consumption of the Norwegian case studies was much higher compared to the British ones. A balance is required between energy efficiency and user thermal comfort in the workplace

    The pedunculopontine tegmental nucleus and the nucleus basalis magnocellularis: Do both have a role in sustained attention?

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    It is well established that nucleus basalis magnocellularis (NbM) lesions impair performance on tests of sustained attention. Previous work from this laboratory has also demonstrated that pedunculopontine tegmental nucleus (PPTg) lesioned rats make more omissions on a test of sustained attention, suggesting that it might also play a role in mediating this function. However, the results of the PPTg study were open to alternative interpretation. We aimed to resolve this by conducting a detailed analysis of the effects of damage to each brain region in the same sustained attention task used in our previous work. Rats were trained in the task before surgery and post-surgical testing examined performance in response to unpredictable light signals of 1500 ms and 4000 ms duration. Data for PPTg lesioned rats were compared to control rats, and rats with 192 IgG saporin infusions centred on the NbM. In addition to operant data, video data of rats' performance during the task were also analysed
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