1,173 research outputs found

    The incidence of liver injury in Uyghur patients treated for TB in Xinjiang Uyghur autonomous region, China, and its association with hepatic enzyme polymorphisms nat2, cyp2e1, gstm1 and gstt1.

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    BACKGROUND AND OBJECTIVE: Of three first-line anti-tuberculosis (anti-TB) drugs, isoniazid is most commonly associated with hepatotoxicity. Differences in INH-induced toxicity have been attributed to genetic variability at several loci, NAT2, CYP2E1, GSTM1and GSTT1, that code for drug-metabolizing enzymes. This study evaluated whether the polymorphisms in these enzymes were associated with an increased risk of anti-TB drug-induced hepatitis in patients and could potentially be used to identify patients at risk of liver injury. METHODS AND DESIGN: In a cross-sectional study, 2244 tuberculosis patients were assessed two months after the start of treatment. Anti-TB drug-induced liver injury (ATLI) was defined as an ALT, AST or bilirubin value more than twice the upper limit of normal. NAT2, CYP2E1, GSTM1 and GSTT1 genotypes were determined using the PCR/ligase detection reaction assays. RESULTS: 2244 patients were evaluated, there were 89 cases of ATLI, a prevalence of 4% 9 patients (0.4%) had ALT levels more than 5 times the upper limit of normal. The prevalence of ATLI was greater among men than women, and there was a weak association with NAT2*5 genotypes, with ATLI more common among patients with the NAT2*5*CT genotype. The sensitivity of the CT genotype for identifying patients with ATLI was 42% and the positive predictive value 5.9%. CT ATLI was more common among slow acetylators (prevalence ratio 2.0 (95% CI 0.95,4.20) )compared to rapid acetylators. There was no evidence that ATLI was associated with CYP2E1 RsaIc1/c1genotype, CYP2E1 RsaIc1/c2 or c2/c2 genotypes, or GSTM1/GSTT1 null genotypes. CONCLUSIONS: In Xinjiang Uyghur TB patients, liver injury was associated with the genetic variant NAT2*5, however the genetic markers studied are unlikely to be useful for screening patients due to the low sensitivity and low positive predictive values for identifying persons at risk of liver injury

    The endothelial glycocalyx prefers albumin for evoking shear stress-induced, nitric oxide-mediated coronary dilatation

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    Background: Shear stress induces coronary dilatation via production of nitric oxide ( NO). This should involve the endothelial glycocalyx ( EG). A greater effect was expected of albumin versus hydroxyethyl starch ( HES) perfusion, because albumin seals coronary leaks more effectively than HES in an EG-dependent way. Methods: Isolated hearts ( guinea pigs) were perfused at constant pressure with Krebs-Henseleit buffer augmented with 1/3 volume 5% human albumin or 6% HES ( 200/0.5 or 450/0.7). Coronary flow was also determined after EG digestion ( heparinase) and with nitro-L-arginine ( NO-L-Ag). Results: Coronary flow ( 9.50 +/- 1.09, 5.10 +/- 0.49, 4.87 +/- 1.19 and 4.15 +/- 0.09 ml/ min/ g for `albumin', `HES 200', `HES 450' and `control', respectively, n = 5-6) did not correlate with perfusate viscosity ( 0.83, 1.02, 1.24 and 0.77 cP, respectively). NO-L-Ag and heparinase diminished dilatation by albumin, but not additively. Alone NO-L-Ag suppressed coronary flow during infusion of HES 450. Electron microscopy revealed a coronary EG of 300 nm, reduced to 20 nm after heparinase. Cultured endothelial cells possessed an EG of 20 nm to begin with. Conclusions: Albumin induces greater endothelial shear stress than HES, despite lower viscosity, provided the EG contains negative groups. HES 450 causes some NO-mediated dilatation via even a rudimentary EG. Cultured endothelial cells express only a rudimentary glycocalyx, limiting their usefulness as a model system. Copyright (c) 2007 S. Karger AG, Basel

    IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

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    Funding: This work was funded by a Career Development Fellowship (1028634) and a project grant (GRNT1028641) awarded to AHa by the Australian National Health & Medical Research Council (NHMRC). IS was supported by The University of Queensland Centennial and IPRS Scholarships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Role of macrophage sialoadhesin in host defense against the sialylated pathogen group B <em>Streptococcus</em>

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    ABSTRACT: Several bacterial pathogens decorate their surfaces with sialic acid (Sia) residues within cell wall components or capsular exopolysaccharides. Sialic acid expression can promote bacterial virulence by blocking complement activation or by engagement of inhibitory sialic acid-binding immunoglobulin-like lectins (Siglecs) on host leukocytes. Expressed at high levels on splenic and lymph node macrophages, sialoadhesin (Sn) is a unique Siglec with an elongated structure that lacks intracellular signaling motifs. Sialoadhesin allows macrophage to engage certain sialylated pathogens and stimulate inflammatory responses, but the in vivo significance of sialoadhesin in infection has not been shown. We demonstrate that macrophages phagocytose the sialylated pathogen group B Streptococcus (GBS) and increase bactericidal activity via sialoadhesin-sialic-acid-mediated recognition. Sialoadhesin expression on marginal zone metallophillic macrophages in the spleen trapped circulating GBS and restricted the spread of the GBS to distant organs, reducing mortality. Specific IgM antibody responses to GBS challenge were also impaired in sialoadhesin-deficient mice. Thus, sialoadhesin represents a key bridge to orchestrate innate and adaptive immune defenses against invasive sialylated bacterial pathogens. KEY MESSAGE: Sialoadhesin is critical for macrophages to phagocytose and clear GBS. Increased GBS organ dissemination in the sialoadhesin-deficient mice. Reduced anti-GBS IgM production in the sialoadhesin-deficient mice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00109-014-1157-y) contains supplementary material, which is available to authorized users

    Incorporating new approach methodologies into regulatory nonclinical pharmaceutical safety assessment

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    New approach methodologies (NAMs) based on human biology enabletheassessment of adverse biological effects of pharmaceuticals and other chemicals. Currently,however, it is unclear how NAMsshould be usedduring drug development to improve human safety evaluation. A series of 5 workshops with 13 international experts (regulators, preclinical scientists and NAMs developers) were conducted to identify feasible NAMsand to discuss how to exploit them in specific safety assessmentcontexts. Participants generated four‘maps’of how NAMs can be exploited in the safety assessment ofthe liver, respiratory, cardiovascular,and central nervous systems. Each map showsrelevant end points measured, tools used (e.g.,cells, assays, platforms), and highlights gaps where furtherdevelopment and validation of NAMs remainsnecessary. Each map addresses the fundamental scientific requirements for the safety assessment of that organ system, providing users with guidance on the selection of appropriate NAMs. In addition to generating the maps, participants offered suggestions for encouraging greater NAM adoption within drug development and their inclusion in regulatory guidelines. A specific recommendation was that pharmaceutical companies should be more transparent about how they use NAMs in-house. As well as giving guidance for the fourorgan systems, the maps providea template that could be used for additional organ safety testing contexts.Moreover, their conversion to an interactive format would enable users to drill down to the detail necessary to answer specific scientific and regulatory questions. 1IntroductionExtensive nonclinical safety studies are undertaken on new pharmaceuticals prior to and alongside clinical trials. Their purpose is to identify and understand the toxic effects of thecompoundin order to determine whether its anticipated benefit versusrisk profile justifies clinical evaluation and, if so, to inform the design and monitoring of clinical studies. The nonclinical safety studies are mandated by regulatory guidelines and include a variety of safety pharmacologyand toxicology investigations.Safety pharmacology studies aimto determinewhether pharmaceuticalscause on-or off-target effects on biological processes which can affect the function of critical organ systems (e.g.,cardiovascular, respiratory, gastrointestinal,and central nervous systems)and to assess potency, which is needed to assess safety margins versushuman clinical drug exposure. Safety pharmacology studiesalso help informthe selectionof follow-on investigations that can aid human risk assessmentand may provide insight into mechanismswhich underlie any effectsthat arise in humans.Multiple leading pharmaceutical companies (e.g.,AstraZeneca, GlaxoSmithKline, Novartis,and Pfizer) have outlined the advantages provided by in vitrosafety pharmacological profiling, including early identification of off-target interactionsandthe prediction ofclinical side effects that may be missed in animalstudies, and have highlighted that these studies enable much more cost-effective and rapid profiling of large numbers of compounds than animal procedures (Bowes et al., 2012).Toxicology studies evaluate systemic organ toxicities, behavioraleffects, reproductive and developmental toxicology, genetic toxicology,eye irritancy and dermal sensitization. They include single and repeat dose studies in rodent and non-rodentanimal species, which identify target organs, assessseverity andreversibility,and define dose-response and no observed adverse effect levels. These are critical parameters which are essential for regulatory decision-makingon whether the compound can be progressed into clinical trials and if so, estimation ofa suitable starting dose,maximum dose, dose escalation regime,andany non-standard clinical safety monitoringthat may be needed.Toxicity observedinnonclinical animal safety studies is an important cause of the high attrition rate of candidate drugs prior to clinicaltrials that occurs inmultiple pharmaceutical companies(Cook et al., 2014).However, many drugs cause clinically serious adverseeffects in humans which are not detectedin animals(Bailey et al., 2015). For example, human drug induced liver injury(DILI),which is not detected in animal safety studies,is animportant cause of attrition late in clinical development, failed licensing and/or of restrictive drug labelling(Watkins, 2011). Attrition due to toxicity observed in animals and/or in humans isanimportant cause of the high failure rate of clinical drug development(Cook et al., 2014; Watkins, 2011; Thomas et al., 2021).New approach methodologies (NAMs)includemethods which predict and evaluate biological processes by which pharmaceuticals may elicit desirable pharmacological effects and/or may cause undesirable toxicity. Many different types of NAMs have been described. Theseinclude simple in vitrocell-based tests, more complex organotypic or microphysiologicalsystems (MPS)/organ-on-a-chipdevices,and whole human tissuesmaintained ex vivo. Interpretation ofthe invivorelevance of the data providedby these methods is complementedbycomputational toolswhichsimulate and predict in vivodrug disposition and kinetics, in particular physiologically based pharmacokinetic (PBPK) models. Accurate in vitroto in vivoextrapolation isfurther aided by human low-dose testing and microdosing studies (phase 0 testing), which provide precise data on systemic human drug exposure and kineticsin vivo

    New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.

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    Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes

    The first World Cell Race

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    Motility is a common property of animal cells. Cell motility is required for embryogenesis [1], tissue morphogenesis [2] and the immune response [3] but is also involved in disease processes, such as metastasis of cancer cells [4]. Analysis of cell migration in native tissue in vivo has yet to be fully explored, but motility can be relatively easily studied in vitro in isolated cells. Recent evidence suggests that cells plated in vitro on thin lines of adhesive proteins printed onto culture dishes can recapitulate many features of in vivo migration on collagen fibers 5, 6. However, even with controlled in vitro measurements, the characteristics of motility are diverse and are dependent on the cell type, origin and external cues. One objective of the first World Cell Race was to perform a large-scale comparison of motility across many different adherent cell types under standardized conditions. To achieve a diverse selection, we enlisted the help of many international laboratories, who submitted cells for analysis. The large-scale analysis, made feasible by this competition-oriented collaboration, demonstrated that higher cell speed correlates with the persistence of movement in the same direction irrespective of cell origin

    Perspectives by patients and physicians on outcomes of mid-urethral sling surgery

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    Introduction and hypothesis: The aim of this study is to determine patient expectations regarding wanted and unwanted sequels of mid-urethral sling (MUS) procedures and to identify mismatches during the physician-patient information exchange prior to MUS procedures. Methods: A patient preference study (40 patients) and a questionnaire study with 20 experts as control group were conducted. Seventeen different sequels, defined by an expert team, were evaluated. Results: Both patients and expert physicians ranked cure and improvement of stress urinary incontinence as the most important goals of treatment. De novo urge urinary incontinence, requiring post-operative intermittent self-catheterisation and dyspareunia were considered to be the most important complications by patients. Time to resume work after the operation and dyspareunia were among the highest rated sequels in the patient group compared to re-operation and intra-operative complications in the expert group. Conclusions: No differences were found in the five most important outcome parameters. In pre-operative counselling and future clinical trials, time to resume work and dyspareunia should be given more consideration by clinicians

    f(R) theories

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    Over the past decade, f(R) theories have been extensively studied as one of the simplest modifications to General Relativity. In this article we review various applications of f(R) theories to cosmology and gravity - such as inflation, dark energy, local gravity constraints, cosmological perturbations, and spherically symmetric solutions in weak and strong gravitational backgrounds. We present a number of ways to distinguish those theories from General Relativity observationally and experimentally. We also discuss the extension to other modified gravity theories such as Brans-Dicke theory and Gauss-Bonnet gravity, and address models that can satisfy both cosmological and local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in Relativity, Published version, Comments are welcom

    Model based PEEP titration versus standard practice in mechanical ventilation: A randomised controlled trial

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    Background: Positive end-expiratory pressure (PEEP) at minimum respiratory elastance during mechanical ventilation (MV) in patients with acute respiratory distress syndrome (ARDS) may improve patient care and outcome. The Clinical utilisation of respiratory elastance (CURE) trial is a two-arm, randomised controlled trial (RCT) investigating the performance of PEEP selected at an objective, model-based minimal respiratory system elastance in patients with ARDS. Methods and design: The CURE RCT compares two groups of patients requiring invasive MV with a partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio ≤ 200; one criterion of the Berlin consensus definition of moderate (≤ 200) or severe (≤ 100) ARDS. All patients are ventilated using pressure controlled (bi-level) ventilation with tidal volume = 6-8 ml/kg. Patients randomised to the control group will have PEEP selected per standard practice (SPV). Patients randomised to the intervention will have PEEP selected based on a minimal elastance using a model-based computerised method. The CURE RCT is a single-centre trial in the intensive care unit (ICU) of Christchurch hospital, New Zealand, with a target sample size of 320 patients over a maximum of 3 years. The primary outcome is the area under the curve (AUC) ratio of arterial blood oxygenation to the fraction of inspired oxygen over time. Secondary outcomes include length of time of MV, ventilator-free days (VFD) up to 28 days, ICU and hospital length of stay, AUC of oxygen saturation (SpO )/FiO during MV, number of desaturation events (SpO < 88%), changes in respiratory mechanics and chest x-ray index scores, rescue therapies (prone positioning, nitric oxide use, extracorporeal membrane oxygenation) and hospital and 90-day mortality. Discussion: The CURE RCT is the first trial comparing significant clinical outcomes in patients with ARDS in whom PEEP is selected at minimum elastance using an objective model-based method able to quantify and consider both inter-patient and intra-patient variability. CURE aims to demonstrate the hypothesized benefit of patient-specific PEEP and attest to the significance of real-time monitoring and decision-support for MV in the critical care environment. Trial registration: Australian New Zealand Clinical Trial Registry, ACTRN12614001069640. Registered on 22 September 2014. (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366838&isReview=true) The CURE RCT clinical protocol and data usage has been granted by the New Zealand South Regional Ethics Committee (Reference number: 14/STH/132). 2 2
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