2,990 research outputs found

    N-acetyl-L-cysteine ameliorates the inflammatory disease process in experimental autoimmune encephalomyelitis in Lewis rats

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    We report that N-acetyl-L-cysteine (NAC) treatment blocked induction of TNF-α, IL-1β, IFN-γ and iNOS in the CNS and attenuated clinical disease in the myelin basic protein induced model of experimental allergic encephalomyelitis (EAE) in Lewis rats. Infiltration of mononuclear cells into the CNS and induction of inflammatory cytokines and iNOS in multiple sclerosis (MS) and EAE have been implicated in subsequent disease progression and pathogenesis. To understand the mechanism of efficacy of NAC against EAE, we examined its effect on the production of cytokines and the infiltration of inflammatory cells into the CNS. NAC treatment attenuated the transmigration of mononuclear cells thereby lessening the neuroinflammatory disease. Splenocytes from NAC-treated EAE animals showed reduced IFN-γ production, a Th1 cytokine and increased IL-10 production, an anti-inflammatory cytokine. Further, splenocytes from NAC-treated EAE animals also showed decreased nitrite production when stimulated in vitro by LPS. These observations indicate that NAC treatment may be of therapeutic value in MS against the inflammatory disease process associated with the infiltration of activated mononuclear cells into the CNS

    Precision planar drift chambers and cradle for the TWIST muon decay spectrometer

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    To measure the muon decay parameters with high accuracy, we require an array of precision drift detector layers whose relative position is known with very high accuracy. This article describes the design, construction and performance of these detectors in the TWIST (TRIUMF Weak Interaction Symmetry Test) spectrometer.Comment: 44 pages, 16 Postscript figures, LaTeX2e, uses Elsevier class elsart.cls, package graphicx, submitted to Nuclear Instruments & Methods in Physics Researc

    Cross section and analyzing power of pol{p}p -> pn pi+ near threshold

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    The cross section and analyzing power of the pol{p}p -> pn pi+ reaction near threshold are estimated in terms of data obtained from the pol{p}p -> d pi+ and pp -> pp pi0 reactions. A simple final state interaction theory is developed which depends weakly upon the form of the pion-production operator and includes some Coulomb corrections. Within the uncertainties of the model and the input data, the approach reproduces well the measured energy dependence of the total cross section and the proton analyzing power at a fixed pion c.m. angle of 90deg, from threshold to T_p = 330 MeV. The variation of the differential cross section with pion angle is also very encouraging.Comment: 20 pages, Latex including 4 eps figure

    Role of heavy-meson exchange in pion production near threshold

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    Recent calculations of ss-wave pion production have severely underestimated the accurately known pp→ppπ0pp\rightarrow pp\pi^0\ total cross section near threshold. In these calculations, only the single-nucleon axial-charge operator is considered. We have calculated, in addition to the one-body term, the two-body contributions to this reaction that arise from the exchange of mesons. We find that the inclusion of the scalar σ\sigma-meson exchange current (and lesser contributions from other mesons) increases the cross section by about a factor of five, and leads to excellent agreement with the data. The results are neither very sensitive to changes in the distorting potential that generates the NNNN wave function, nor to different choices for the meson-nucleon form factors. We argue that pp→ppπ0pp\rightarrow pp\pi^0\ data provide direct experimental evidence for meson-exchange contributions to the axial current.Comment: 28 Pages, IU-NTC #93-0

    SWiss Atorvastatin and Interferon Beta-1b Trial In Multiple Sclerosis (SWABIMS) - rationale, design and methodology

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    BACKGROUND: Statins have anti-inflammatory and immunomodulatory properties in addition to their lipid-lowering effects. Currently, the effects of statins on multiple sclerosis are still controversial. Therefore, randomized clinical trials are needed to provide better evidence on the therapeutic potential of statins in multiple sclerosis. The SWiss Atorvastatin and Interferon Beta-1b trial in Multiple Sclerosis (SWABIMS) evaluates the efficacy, safety and tolerability of atorvastatin 40 mg per os daily and subcutaneous interferon beta-1b every other day compared to monotherapy with subcutaneous interferon beta-1b every other day in patients with relapsing-remitting multiple sclerosis. METHODS/DESIGN: SWABIMS is a multi-centre, randomized, parallel-group, rater-blinded, Phase IIb-study conducted in eight hospitals in Switzerland. 80 treatment naïve patients with relapsing-remitting forms of multiple sclerosis will receive subcutaneous interferon beta-1b for three months. Afterwards, they are randomized into two equal-sized parallel arms, receiving atorvastatin 40 mg/d or not in addition to interferon beta-1b for another 12 months. Disease activity measured by the proportion of patients with new T2 lesions is the primary endpoint. DISCUSSION: SWABIMS is designed to give further information about the therapeutic effect of atorvastatin 40 mg per os daily as add-on therapy to interferon beta-1b in patients with relapsing-remitting multiple sclerosis. Furthermore important safety and tolerability data will be generated. TRIAL REGISTRATION: http://www.clinicaltrials.gov. Identifier: NCT00942591; Swissmedic reference number: 2005DR2119

    A search for two body muon decay signals

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    Lepton family number violation is tested by searching for μ+→e+X0\mu^+\to e^+X^0 decays among the 5.8×108\times 10^8 positive muon decay events analyzed by the TWIST collaboration. Limits are set on the production of both massless and massive X0X^0 bosons. The large angular acceptance of this experiment allows limits to be placed on anisotropic μ+→e+X0\mu^+\to e^+X^0 decays, which can arise from interactions violating both lepton flavor and parity conservation. Branching ratio limits of order 10−510^{-5} are obtained for bosons with masses of 13 - 80 MeV/c2^2 and with different decay asymmetries. For bosons with masses less than 13 MeV/c2^{2} the asymmetry dependence is much stronger and the 90% limit on the branching ratio varies up to 5.8×10−55.8 \times 10^{-5}. This is the first study that explicitly evaluates the limits for anisotropic two body muon decays.Comment: 7 pages, 5 figures, 2 tables, accepted by PR

    Dependence of pp->pp pi0 near Threshold on the Spin of the Colliding Nucleons

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    A polarized internal atomic hydrogen target and a stored, polarized beam are used to measure the spin-dependent total cross section Delta_sigma_T/sigma_tot, as well as the polar integrals of the spin correlation coefficient combination A_xx-A_yy, and the analyzing power A_y for pp-> pp pi0 at four bombarding energies between 325 and 400 MeV. This experiment is made possible by the use of a cooled beam in a storage ring. The polarization observables are used to study the contribution from individual partial waves.Comment: 6 pages, 1 table, 4 figures, corrected equations 2 and
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