847 research outputs found

    BAFF and MyD88 signals promote a lupuslike disease independent of T cells

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    Systemic lupus erythernatosus (SLE) is a systemic autoimmune disease characterized by the production of autoantibodies. However, the underlying cause of disease appears to relate to defects in T cell tolerance or T cell help to 13 cells. Transgenic (Tg) mice over-expressing the cytokine 13 cell-activating factor of the tumor necrosis factor family (BAFF) develop an autoimmune disorder similar to SLE and show impaired B cell tolerance and altered T cell differentiation. We generated BAFF Tg mice that were completely deficient in T cells, and, surprisingly, these mice developed an SLE-like disease indistinguishable from that of BAFF Tg mice. Autoimmunity in BAFF Tg mice did, however, require 13 cell-intrinsic signals through the Toll-like receptor (TLR)-associated signaling adaptor MyD88, which controlled the production of proinflammatory autoantibody isotypes. TLR7/9 activation strongly up-regulated expression of transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), which is a receptor for BAFF involved in 13 cell responses to T cell-independent antigens. Moreover, BAFF enhanced TLR7/9 expression on 13 cells and TLR-mediated production of autoantibodies. Therefore, autoirnmunity in BAFF Tg mice results from altered 13 cell tolerance, but requires TLR signaling and is independent of T cell help. It is possible that SLE patients with elevated levels of BAFF show a similar basis for disease

    Canagliflozin and atrial fibrillation in type 2 diabetes mellitus: A secondary analysis from the CANVAS Program and CREDENCE trial and meta-analysis

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    Aim: To assess the effects of canagliflozin on the incidence of atrial fibrillation/atrial flutter (AF/AFL) and other key cardiorenal outcomes in a pooled analysis of the CANVAS and CREDENCE trials. Materials and Methods: Participants with type 2 diabetes and high risk of cardiovascular disease or chronic kidney disease were included and randomly assigned to canagliflozin or placebo. We explored the effects of canagliflozin on the incidence of first AF/AFL events and AF/AFL-related complications (ischaemic stroke/transient ischaemic attack/hospitalization for heart failure). Major adverse cardiovascular events and a renal-specific outcome by baseline AF/AFL status were analysed using Cox regression models. Results: Overall, 354 participants experienced a first AF/AFL event. Canagliflozin had no detectable effect on AF/AFL (hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.67-1.02) compared with placebo. Subgroup analysis, however, suggested a possible reduction in AF/AFL in those with no AF/AFL history (HR 0.78, 95% CI 0.62-0.99). Canagliflozin was also associated with a reduction in AF/AFL-related complications (HR 0.74, 95% CI 0.65-0.86). There was no evidence of treatment heterogeneity by baseline AF/AFL history for other key cardiorenal outcomes (all Pinteraction > 0.14). Meta-analysis of five sodium-glucose cotransporter-2 (SGLT2) inhibitor trials demonstrated a 19% reduction in AF/AFL events with active treatment (HR 0.81, 95% CI 0.72-0.92). Conclusions: Overall, a significant effect of canagliflozin on the incidence of AF/AFL events could not be shown, however, a possible reduction in AF/AFL events in those with no prior history requires further investigation. Meta-analysis suggests SGLT2 inhibition reduces AF/AFL incidence

    Utilization of a deoxynucleoside diphosphate substrate by HIV reverse transcriptase

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    Background: Deoxynucleoside triphosphates (dNTPs) are the normal substrates for DNA sysnthesis is catalyzed by polymerases such as HIV-1 reverse transcriptase (RT). However, substantial amounts of deoxynucleoside diphosphates (dNDPs) are also present in the cell. Use of dNDPs in HIV-1 DNA sysnthesis could have significant implications for the efficacy of nucleoside RT inhibitors such as AZT which are first line therapeutics fro treatment of HIV infection. Our earlier work on HIV-1 reverse transcriptase (RT) suggested that the interaction between the γ phosphate of the incoming dNTP and RT residue K65 in the active site is not essential for dNTP insertion, implying that this polymerase may be able to insert dNPs in addition to dNTPs. Methodology/Principal Findings: We examined the ability of recombinant wild type (wt) and mutant RTs with substitutions at residue K65 to utilize a dNDP substrate in primer extension reactions. We found that wild type HIV-1 RT indeed catalyzes incorporation of dNDP substrates whereas RT with mutations of residue K645 were unable to catalyze this reaction. Wild type HIV-1 RT also catalyzed the reverse reaction, inorganic phosphate-dependent phosphorolysis. Nucleotide-mediated phosphorolytic removal of chain-terminating 3′-terminal nucleoside inhibitors such as AZT forms the basis of HIV-1 resistance to such drugs, and this removal is enhanced by thymidine analog mutations (TAMs). We found that both wt and TAM-containing RTs were able to catalyze Pi-mediated phosphorolysis of 3′-terminal AZT at physiological levels of Pi with an efficacy similar to that for ATP-dependent AZT-excision. Conclusion: We have identified two new catalytic function of HIV-1 RT, the use of dNDPs as substrates for DNA synthesis, and the use of Pi as substrate for phosphorolytic removal of primer 3′-terminal nucleotides. The ability to insert dNDPs has been documented for only one other DNA polymerase The RB69 DNA polymerase and the reverse reaction employing inorganic phosphate has not been documented for any DNA polymerase. Importantly, our results show that Pi-mediated phosphorolysis can contribute to AZT resistance and indicates that factors that influence HIV resistance to AZT are more complex than previously appreciated. © 2008 Garforth et al

    Use of low-dose oral theophylline as an adjunct to inhaled corticosteroids in preventing exacerbations of chronic obstructive pulmonary disease: study protocol for a randomised controlled trial.

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    BACKGROUND: Chronic obstructive pulmonary disease (COPD) is associated with high morbidity, mortality, and health-care costs. An incomplete response to the anti-inflammatory effects of inhaled corticosteroids is present in COPD. Preclinical work indicates that 'low dose' theophylline improves steroid responsiveness. The Theophylline With Inhaled Corticosteroids (TWICS) trial investigates whether the addition of 'low dose' theophylline to inhaled corticosteroids has clinical and cost-effective benefits in COPD. METHOD/DESIGN: TWICS is a randomised double-blind placebo-controlled trial conducted in primary and secondary care sites in the UK. The inclusion criteria are the following: an established predominant respiratory diagnosis of COPD (post-bronchodilator forced expiratory volume in first second/forced vital capacity [FEV1/FVC] of less than 0.7), age of at least 40 years, smoking history of at least 10 pack-years, current inhaled corticosteroid use, and history of at least two exacerbations requiring treatment with antibiotics or oral corticosteroids in the previous year. A computerised randomisation system will stratify 1424 participants by region and recruitment setting (primary and secondary) and then randomly assign with equal probability to intervention or control arms. Participants will receive either 'low dose' theophylline (Uniphyllin MR 200 mg tablets) or placebo for 52 weeks. Dosing is based on pharmacokinetic modelling to achieve a steady-state serum theophylline of 1-5 mg/l. A dose of theophylline MR 200 mg once daily (or placebo once daily) will be taken by participants who do not smoke or participants who smoke but have an ideal body weight (IBW) of not more than 60 kg. A dose of theophylline MR 200 mg twice daily (or placebo twice daily) will be taken by participants who smoke and have an IBW of more than 60 kg. Participants will be reviewed at recruitment and after 6 and 12 months. The primary outcome is the total number of participant-reported COPD exacerbations requiring oral corticosteroids or antibiotics during the 52-week treatment period. DISCUSSION: The demonstration that 'low dose' theophylline increases the efficacy of inhaled corticosteroids in COPD by reducing the incidence of exacerbations is relevant not only to patients and clinicians but also to health-care providers, both in the UK and globally. TRIAL REGISTRATION: Current Controlled Trials ISRCTN27066620 was registered on Sept. 19, 2013, and the first subject was randomly assigned on Feb. 6, 2014

    Time spent with cats is never wasted: Lessons learned from feline acromegalic cardiomyopathy, a naturally occurring animal model of the human disease

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    <div><p>Background</p><p>In humans, acromegaly due to a pituitary somatotrophic adenoma is a recognized cause of increased left ventricular (LV) mass. Acromegalic cardiomyopathy is incompletely understood, and represents a major cause of morbidity and mortality. We describe the clinical, echocardiographic and histopathologic features of naturally occurring feline acromegalic cardiomyopathy, an emerging disease among domestic cats.</p><p>Methods</p><p>Cats with confirmed hypersomatotropism (IGF-1>1000ng/ml and pituitary mass; n = 67) were prospectively recruited, as were two control groups: diabetics (IGF-1<800ng/ml; n = 24) and healthy cats without known endocrinopathy or cardiovascular disease (n = 16). Echocardiography was performed in all cases, including after hypersomatotropism treatment where applicable. Additionally, tissue samples from deceased cats with hypersomatotropism, hypertrophic cardiomyopathy and age-matched controls (n = 21 each) were collected and systematically histopathologically reviewed and compared.</p><p>Results</p><p>By echocardiography, cats with hypersomatotropism had a greater maximum LV wall thickness (6.5mm, 4.1–10.1mm) than diabetic (5.9mm, 4.2–9.1mm; Mann Whitney, p<0.001) or control cats (5.2mm, 4.1–6.5mm; Mann Whitney, p<0.001). Left atrial diameter was also greater in cats with hypersomatotropism (16.6mm, 13.0–29.5mm) than in diabetic (15.4mm, 11.2–20.3mm; Mann Whitney, p<0.001) and control cats (14.0mm, 12.6–17.4mm; Mann Whitney, p<0.001). After hypophysectomy and normalization of IGF-1 concentration (n = 20), echocardiographic changes proved mostly reversible. As in humans, histopathology of the feline acromegalic heart was dominated by myocyte hypertrophy with interstitial fibrosis and minimal myofiber disarray.</p><p>Conclusions</p><p>These results demonstrate cats could be considered a naturally occurring model of acromegalic cardiomyopathy, and as such help elucidate mechanisms driving cardiovascular remodeling in this disease.</p></div

    Heuristics-based detection to improve text/graphics segmentation in complex engineering drawings.

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    The demand for digitisation of complex engineering drawings becomes increasingly important for the industry given the pressure to improve the efficiency and time effectiveness of operational processes. There have been numerous attempts to solve this problem, either by proposing a general form of document interpretation or by establishing an application dependant framework. Moreover, text/graphics segmentation has been presented as a particular form of addressing document digitisation problem, with the main aim of splitting text and graphics into different layers. Given the challenging characteristics of complex engineering drawings, this paper presents a novel sequential heuristics-based methodology which is aimed at localising and detecting the most representative symbols of the drawing. This implementation enables the subsequent application of a text/graphics segmentation method in a more effective form. The experimental framework is composed of two parts: first we show the performance of the symbol detection system and then we present an evaluation of three different state of the art text/graphic segmentation techniques to find text on the remaining image

    Upper atmospheres and ionospheres of planets and satellites

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    The upper atmospheres of the planets and their satellites are more directly exposed to sunlight and solar wind particles than the surface or the deeper atmospheric layers. At the altitudes where the associated energy is deposited, the atmospheres may become ionized and are referred to as ionospheres. The details of the photon and particle interactions with the upper atmosphere depend strongly on whether the object has anintrinsic magnetic field that may channel the precipitating particles into the atmosphere or drive the atmospheric gas out to space. Important implications of these interactions include atmospheric loss over diverse timescales, photochemistry and the formation of aerosols, which affect the evolution, composition and remote sensing of the planets (satellites). The upper atmosphere connects the planet (satellite) bulk composition to the near-planet (-satellite) environment. Understanding the relevant physics and chemistry provides insight to the past and future conditions of these objects, which is critical for understanding their evolution. This chapter introduces the basic concepts of upper atmospheres and ionospheres in our solar system, and discusses aspects of their neutral and ion composition, wind dynamics and energy budget. This knowledge is key to putting in context the observations of upper atmospheres and haze on exoplanets, and to devise a theory that explains exoplanet demographics.Comment: Invited Revie

    Experiences of patients with chronic gastrointestinal conditions: in their own words

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    <p>Abstract</p> <p>Background</p> <p>Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are chronic conditions affecting millions of individuals in the United States. The symptoms are well-documented and can be debilitating. How these chronic gastrointestinal (GI) conditions impact the daily lives of those afflicted is not well documented, especially from a patient's perspective.</p> <p>Methods</p> <p>Here we describe data from a series of 22 focus groups held at three different academic medical centers with individuals suffering from chronic GI conditions. All focus groups were audio recorded and transcribed. Two research team members independently analyzed transcripts from each focus group following an agreed upon coding scheme.</p> <p>Results</p> <p>One-hundred-thirty-six individuals participated in our study, all with a chronic GI related condition. They candidly discussed three broad themes that characterize their daily lives: identification of disease and personal identity, medications and therapeutics, and daily adaptations. These all tie to our participants trying to deal with symptoms on a daily basis. We find that a recurrent topic underlying these themes is the dichotomy of experiencing uncertainty and striving for control.</p> <p>Conclusions</p> <p>Study participants' open dialogue and exchange of experiences living with a chronic GI condition provide insight into how these conditions shape day-to-day activities. Our findings provide fertile ground for discussions about how clinicians might best facilitate, acknowledge, and elicit patients' stories in routine care to better address their experience of illness.</p

    Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

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    In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse
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