759 research outputs found

    The EIIIA domain from astrocyte-derived fibronectin mediates proliferation of oligodendrocyte progenitor cells following CNS demyelination.

    Get PDF
    Central nervous system remyelination by oligodendrocyte progenitor cells (OPCs) ultimately fails in the majority of multiple sclerosis (MS) lesions. Remyelination benefits from transient expression of factors that promote migration and proliferation of OPCs, which may include fibronectin (Fn). Fn is present in demyelinated lesions in two major forms; plasma Fn (pFn), deposited following blood-brain barrier disruption, and cellular Fn, synthesized by resident glial cells and containing alternatively spliced domains EIIIA and EIIIB. Here, we investigated the distinctive roles that astrocyte-derived Fn (aFn) and pFn play in remyelination. We used an inducible Cre-lox recombination strategy to selectively remove pFn, aFn or both from mice, and examined the impact on remyelination of toxin-induced demyelinated lesions of spinal cord white matter. This approach revealed that astrocytes are a major source of Fn in demyelinated lesions. Furthermore, following aFn conditional knockout, the number of OPCs recruited to the demyelinated lesion decreased significantly, whereas OPC numbers were unaltered following pFn conditional knockout. However, remyelination completed normally following conditional knockout of aFn and pFn. Both the EIIIA and EIIIB domains of aFn were expressed following demyelination, and in vitro assays demonstrated that the EIIIA domain of aFn mediates proliferation of OPCs, but not migration. Therefore, although the EIIIA domain from aFn mediates OPC proliferation, aFn is not essential for successful remyelination. Since previous findings indicated that astrocyte-derived Fn aggregates in chronic MS lesions inhibit remyelination, aFn removal may benefit therapeutic strategies to promote remyelination in MS.JMJS is recipient of a Junior Scientific Masterclass MD/PhD fellowship from the University Medical Center Groningen. This work was supported by grants from the Netherlands Organization of Scientific Research (NWO, WB, VIDI and Aspasia), the Dutch MS Research Foundation (‘Stichting MS Research’, WB, JMJS, DH), the UK MS Society (CZ, RJMF), and the Research School of Behavioral and Cognitive Neurosciences (BCN, JMJS). Parts of this study were performed at the UMCG Microscopy and Imaging Center (UMIC), which is supported by NWO grants 40-00506-98-9021 and 175-010-2009-023.This is the final version of the article. It was first published by Wiley at http://dx.doi.org/10.1002/glia.2274

    The epidemiology of Candida species isolated from urinary tract infections

    Get PDF
    Candida spp. are members of a genus, including closely related fungal species that cause a variety of infections. Objectives: The aim of this study was the isolation of various Candida species from vulvovaginitis and urethra of patients in Neyshabur, Northeast Iran from 2013 to 2015. Methods: This descriptive-analytical and cross-sectional study was performed to identify Candida spp. causing vulvovaginitis and Urinary Tract Infection (UTI) at a referral laboratory in Neyshabur district, Khorasan Razavi Province. A total of 451 vaginal and midstream urine samples were collected. Ten micro-liters of each specimen was cultured on CHROM agar plates and then incubated at 37°C for 24 to 48 hours, aerobically. Candida species were identified based on colony morphology, germ tube production and micro-morphology on corn meal agar including 1% Tween 80. Results: The mean age of the patients was 34.7_16.3. Candida albicans was the predominant species isolated. Moreover, age groups of 21 to 30 and 0 to 1 years were the most and the least infected individuals. Moreover, Candida spp. were significantly morecommon in females compared to males (P value 103. Conclusions: In this study, C. albicans was the most common species isolated from patients with vulvovaginitis and UTI, and significantly more common amongst females compared to males. The prevalence of candida spp. had significantly declined from 2013 to 2015. Moreover, the candida spp. counts were mostly higher than 103cfu/mL

    Th17 Cells Induce Ectopic Lymphoid Follicles in Central Nervous System Tissue Inflammation

    Get PDF
    Ectopic lymphoid follicles are hallmarks of chronic autoimmune inflammatory diseases such as multiple sclerosis (MS), rheumatoid arthritis, Sjögren's syndrome, and myasthenia gravis. However, the effector cells and mechanisms that induce their development are unknown. Here we showed that in experimental autoimmune encephalomyelitis (EAE), the animal model of MS, Th17 cells specifically induced ectopic lymphoid follicles in the central nervous system (CNS). Development of ectopic lymphoid follicles was partly dependent on the cytokine interleukin 17 (IL-17) and on the cell surface molecule Podoplanin (Pdp), which was expressed on Th17 cells, but not on other effector T cell subsets. Pdp was also crucial for the development of secondary lymphoid structures: Pdp-deficient mice lacked peripheral lymph nodes and had a defect in forming normal lymphoid follicles and germinal centers in spleen and lymph node remnants. Thus, Th17 cells are uniquely endowed to induce tissue inflammation, characterized by ectopic lymphoid follicles within the target organ

    Candida albicans Possesses Sap7 as a Pepstatin A-Insensitive Secreted Aspartic Protease

    Get PDF
    BACKGROUND: Candida albicans, a commensal organism, is a part of the normal flora of healthy individuals. However, once the host immunity is compromised, C. albicans opportunistically causes recurrent superficial or fatal systemic candidiasis. Secreted aspartic proteases (Sap), encoded by 10 types of SAP genes, have been suggested to contribute to various virulence processes. Thus, it is important to elucidate their biochemical properties for better understanding of the molecular mechanisms that how Sap isozymes damage host tissues. METHODOLOGY/PRINCIPAL FINDINGS: The SAP7 gene was cloned from C. albicans SC5314 and heterogeneously produced by Pichia pastoris. Measurement of Sap7 proteolytic activity using the FRETS-25Ala library showed that Sap7 was a pepstatin A-insensitive protease. To understand why Sap7 was insensitive to pepstatin A, alanine substitution mutants of Sap7 were constructed. We found that M242A and T467A mutants had normal proteolytic activity and sensitivity to pepstatin A. M242 and T467 were located in close proximity to the entrance to an active site, and alanine substitution at these positions widened the entrance. Our results suggest that this alteration might allow increased accessibility of pepstatin A to the active site. This inference was supported by the observation that the T467A mutant has stronger proteolytic activity than the wild type. CONCLUSIONS/SIGNIFICANCE: We found that Sap7 was a pepstatin A-insensitive protease, and that M242 and T467 restricted the accessibility of pepstatin A to the active site. This finding will lead to the development of a novel protease inhibitor beyond pepstatin A. Such a novel inhibitor will be an important research tool as well as pharmaceutical agent for patients suffering from candidiasis

    Retinopathy of prematurity and risk factors: a prospective cohort study

    Get PDF
    BACKGROUND: Increased survival of extremely low birth infants due to advances in antenatal and neonatal care has resulted in a population of infants at high risk of developing retinopathy of prematurity (ROP). Therapeutic interventions include the use of antenatal and postnatal steroids however, their effects on the severity of ROP is in dispute. In addition, it has not been investigated whether severe ROP is due to therapeutic interventions or due to the severity of illness. The aim of the present study was to assess the association between the incidence of severe retinopathy of prematurity (greater than stage 2 – International classification of ROP) and mechanical ventilation, oxygen therapy, gestational age, antenatal and postnatal steroids in extremely low birth weight infants. METHODS: Neonates admitted to the neonatal intensive care unit in Lansing, Michigan, during 1993–2000 were followed to determine factors influencing the development of severe retinopathy of prematurity. Ophthalmologic examinations were started at 6 weeks and followed until resolution. We used logistic regression to estimate the relative risk (odds ratio) associated with risk factors of ROP. RESULTS: Of the neonates with ≤ 1500 g birth weight, admitted to the neonatal intensive care unit, 85% (616/725) survived. Severe retinopathy of prematurity was detected in 7.8% of 576 neonates who had eye examinations. Neonates of lower gestational age (≤ 25 weeks and 26–28 weeks) had an increased odds ratio of 8.49 and 3.19 for the development of severe retinopathy of prematurity, respectively, compared to those 29 weeks and older. Late postnatal steroid treatment starting after 3 weeks of life showed 2.9-fold increased odds ratio, in particular administration for two weeks and more (OR: 4.09, 95% CI: 1.52–11.03). With increasing antenatal steroids courses the risk of severe retinopathy of prematurity decreased, however, it was not significant. Lower gestational age, dependence on ventilation, and use of postnatal steroids were intertwined. Simultaneous presence of these factors seems to indicate severe disease status. CONCLUSION: Prolonged and late postnatal steroids treatment in very low birth weight infants may pose an increased risk for the development of severe retinopathy of prematurity; however, use of postnatal steroids may also be a marker for severity of illness. Further studies need to focus on biologic markers in the pathogenesis of retinopathy of prematurity and to better understand the influence of therapies

    NG2 and phosphacan are present in the astroglial scar after human traumatic spinal cord injury

    Get PDF
    BACKGROUND: A major class of axon growth-repulsive molecules associated with CNS scar tissue is the family of chondroitin sulphate proteoglycans (CSPGs). Experimental spinal cord injury (SCI) has demonstrated rapid re-expression of CSPGs at and around the lesion site. The pharmacological digestion of CSPGs in such lesion models results in substantially enhanced axonal regeneration and a significant functional recovery. The potential therapeutic relevance of interfering with CSPG expression or function following experimental injuries seems clear, however, the spatio-temporal pattern of expression of individual members of the CSPG family following human spinal cord injury is only poorly defined. In the present correlative investigation, the expression pattern of CSPG family members NG2, neurocan, versican and phosphacan was studied in the human spinal cord. METHODS: An immunohistochemical investigation in post mortem samples of control and lesioned human spinal cords was performed. All patients with traumatic SCI had been clinically diagnosed as having "complete" injuries and presented lesions of the maceration type. RESULTS: In sections from control spinal cord, NG2 immunoreactivity was restricted to stellate-shaped cells corresponding to oligodendrocyte precursor cells. The distribution patterns of phosphacan, neurocan and versican in control human spinal cord parenchyma were similar, with a fine reticular pattern being observed in white matter (but also located in gray matter for phosphacan). Neurocan staining was also associated with blood vessel walls. Furthermore, phosphacan, neurocan and versican were present in the myelin sheaths of ventral and dorsal nerve roots axons. After human SCI, NG2 and phosphacan were both detected in the evolving astroglial scar. Neurocan and versican were detected exclusively in the lesion epicentre, being associated with infiltrating Schwann cells in the myelin sheaths of invading peripheral nerve fibres from lesioned dorsal roots. CONCLUSION: NG2 and phosphacan were both present in the evolving astroglial scar and, therefore, might play an important role in the blockade of successful CNS regeneration. Neurocan and versican, however, were located at the lesion epicentre, associated with Schwann cell myelin on regenerating peripheral nerve fibres, a distribution that was unlikely to contribute to failed CNS axon regeneration. The present data points to the importance of such correlative investigations for demonstrating the clinical relevance of experimental data

    A Long Baseline Neutrino Oscillation Experiment Using J-PARC Neutrino Beam and Hyper-Kamiokande

    Get PDF
    Document submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresDocument submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresDocument submitted to 18th J-PARC PAC meeting in May 2014. 50 pages, 41 figuresHyper-Kamiokande will be a next generation underground water Cherenkov detector with a total (fiducial) mass of 0.99 (0.56) million metric tons, approximately 20 (25) times larger than that of Super-Kamiokande. One of the main goals of Hyper-Kamiokande is the study of CPCP asymmetry in the lepton sector using accelerator neutrino and anti-neutrino beams. In this document, the physics potential of a long baseline neutrino experiment using the Hyper-Kamiokande detector and a neutrino beam from the J-PARC proton synchrotron is presented. The analysis has been updated from the previous Letter of Intent [K. Abe et al., arXiv:1109.3262 [hep-ex]], based on the experience gained from the ongoing T2K experiment. With a total exposure of 7.5 MW ×\times 107^7 sec integrated proton beam power (corresponding to 1.56×10221.56\times10^{22} protons on target with a 30 GeV proton beam) to a 2.52.5-degree off-axis neutrino beam produced by the J-PARC proton synchrotron, it is expected that the CPCP phase δCP\delta_{CP} can be determined to better than 19 degrees for all possible values of δCP\delta_{CP}, and CPCP violation can be established with a statistical significance of more than 3σ3\,\sigma (5σ5\,\sigma) for 7676% (5858%) of the δCP\delta_{CP} parameter space

    Search for astronomical neutrinos from blazar TXS 0506+056 in super-kamiokande

    Get PDF
    We report a search for astronomical neutrinos in the energy region from several GeV to TeV in the direction of the blazar TXS 0506+056 using the Super-Kamiokande detector following the detection of a 100 TeV neutrinos from the same location by the IceCube collaboration. Using Super-Kamiokande neutrino data across several data samples observed from 1996 April to 2018 February we have searched for both a total excess above known backgrounds across the entire period as well as localized excesses on smaller timescales in that interval. No significant excess nor significant variation in the observed event rate are found in the blazar direction. Upper limits are placed on the electron- and muon-neutrino fluxes at the 90% confidence level as 6.0 × 10−7 and 4.5 × 10−7–9.3 × 10−10 [erg cm−2 s−1], respectively

    The effective rate of influenza reassortment is limited during human infection

    Get PDF
    We characterise the evolutionary dynamics of influenza infection described by viral sequence data collected from two challenge studies conducted in human hosts. Viral sequence data were collected at regular intervals from infected hosts. Changes in the sequence data observed across time show that the within-host evolution of the virus was driven by the reversion of variants acquired during previous passaging of the virus. Treatment of some patients with oseltamivir on the first day of infection did not lead to the emergence of drug resistance variants in patients. Using an evolutionary model, we inferred the effective rate of reassortment between viral segments, measuring the extent to which randomly chosen viruses within the host exchange genetic material. We find strong evidence that the rate of effective reassortment is low, such that genetic associations between polymorphic loci in different segments are preserved during the course of an infection in a manner not compatible with epistasis. Combining our evidence with that of previous studies we suggest that spatial heterogeneity in the viral population may reduce the extent to which reassortment is observed. Our results do not contradict previous findings of high rates of viral reassortment in vitro and in small animal studies, but indicate that in human hosts the effective rate of reassortment may be substantially more limited.CJRI is supported by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant Number 101239/Z/13/Z) and received support from the National Science Foundation Research Coordination Network on Infectious Disease Evolution Across Scales. KK, ASL, CWW, and MTM were funded by NIGMS U54-GM111274, the MIDAS Center for Inference and Dynamics of Infectious Disease. ASL acknowledges support from the MSTP training grant number T32 GM007171. GJDS was supported by the Duke-NUS Signature Research Programme funded by the Ministry of Health, Singapore and by contract HHSN272201400006C from the National Institute of Allergy and Infectious Disease, National Institutes of Health, Department of Health and Human Services, USA. DEW, RAH, XL, AR, TBS, SRD and also the influenza whole genome sequencing were supported with federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contract HHSN272200900007C. GSG was funded by the Defense Advanced Research Projects Agency under grant number DARPA-N66001-07-C-2024. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Evolution Across Scales. KK, ASL, CWW, and MTM were funded by NIGMS U54- GM111274, the MIDAS Center for Inference and Dynamics of Infectious Disease. DEW, RAH, XL, AR, TBS, and SRD were supported with federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contract HHSN272200900007C. GSG was funded by the Defense Advanced Research Projects Agency under grant number DARPA-N66001-07-C-2024. This work was performed using the Darwin Supercomputer of the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/), provided by Dell Inc. using Strategic Research Infrastructure Funding from the Higher Education Funding Council for England and funding from the Science and Technology Facilities Council
    corecore