964 research outputs found

    Milk fat globule epidermal growth factor-factor 8-derived peptide attenuates organ injury and improves survival in sepsis

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    INTRODUCTION: Sepsis involves overwhelming inflammatory responses with subsequent immune-suppression that can lead to multiple organ dysfunction and ultimately death. Milk fat globule epidermal growth factor-factor 8 (MFG-E8) is a secretory protein found to have multiple biological activities against autoimmune and inflammatory diseases. MFG-E8 contains an Arg-Gly-Asp (RGD) motif involved in cell-cell and cell-matrix interactions. In sepsis, excessive neutrophils migration through endothelial cells and matrix to sites of inflammation results in organ damage. We hypothesized that MFG-E8-derived short peptides (MSP) flanking its RGD motif could provide protection against organ injury in sepsis. METHODS: The differentiated human neutrophil-like HL-60 cells (dHL60) were incubated with a series of peptides flanking the RGD motif of human MFG-E8 for a cell adhesion assay to fibronectin or human pulmonary artery endothelial cells (PAECs). For the induction of sepsis, male C57BL/6 mice (20–25 g) were subjected to cecal ligation and puncture (CLP). Peptide MSP68 (1 mg/kg body weight) or normal saline (vehicle) was injected intravenously at 2 h after CLP. Blood and tissue samples were collected at 20 h after CLP for various measurements. RESULTS: After screening, peptide MSP68 (VRGDV) had the highest inhibition of dHL-60 cell adhesion to fibronectin by 55.8 % and to PAEC by 67.7 %. MSP68 treatment significantly decreased plasma levels of organ injury marker AST by 37.1 % and the proinflammatory cytokines IL-6 and TNF-α by 61.9 % and 22.1 %, respectively after CLP. MSP68 improved the integrity of microscopic architectures, decreased IL-6 levels in the lungs by 85.1 %, and reduced apoptosis. MSP68 treatment also significantly reduced the total number of neutrophil infiltration by 61.9 % and 48.3 % as well as MPO activity by 40.8 % and 47.3 % in the lungs and liver, respectively, after CLP. Moreover, the number of bacteria translocated to mesenteric lymph nodes was decreased by 57 % with MSP68 treatment. Finally, the 10-day survival rate was increased from 26 % in the vehicle group to 58 % in the MSP68-treated group. CONCLUSIONS: MSP68 effectively inhibits excessive neutrophils infiltrating to organs, leading to moderate attenuation of organ injury and significantly improved survival in septic mice. Thus, MSP68 may be a potential therapeutic agent for treating sepsis

    The Human Nasal Microbiota and Staphylococcus aureus Carriage

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    BACKGROUND: Colonization of humans with Staphylococcus aureus is a critical prerequisite of subsequent clinical infection of the skin, blood, lung, heart and other deep tissues. S. aureus persistently or intermittently colonizes the nares of approximately 50% of healthy adults, whereas approximately 50% of the general population is rarely or never colonized by this pathogen. Because microbial consortia within the nasal cavity may be an important determinant of S. aureus colonization we determined the composition and dynamics of the nasal microbiota and correlated specific microorganisms with S. aureus colonization. METHODOLOGY/PRINCIPAL FINDINGS: Nasal specimens were collected longitudinally from five healthy adults and a cross-section of hospitalized patients (26 S. aureus carriers and 16 non-carriers). Culture-independent analysis of 16S rRNA sequences revealed that the nasal microbiota of healthy subjects consists primarily of members of the phylum Actinobacteria (e.g., Propionibacterium spp. and Corynebacterium spp.), with proportionally less representation of other phyla, including Firmicutes (e.g., Staphylococcus spp.) and Proteobacteria (e.g. Enterobacter spp). In contrast, inpatient nasal microbiotas were enriched in S. aureus or Staphylococcus epidermidis and diminished in several actinobacterial groups, most notably Propionibacterium acnes. Moreover, within the inpatient population S. aureus colonization was negatively correlated with the abundances of several microbial groups, including S. epidermidis (p = 0.004). CONCLUSIONS/SIGNIFICANCE: The nares environment is colonized by a temporally stable microbiota that is distinct from other regions of the integument. Negative association between S. aureus, S. epidermidis, and other groups suggests microbial competition during colonization of the nares, a finding that could be exploited to limit S. aureus colonization

    Search for Charged Higgs Bosons in e+e- Collisions at \sqrt{s} = 189 GeV

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    A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 176.4 pb^-1. Higgs decays into a charm and a strange quark or into a tau lepton and its associated neutrino are considered. The observed events are consistent with the expectations from Standard Model background processes. A lower limit of 65.5 GeV on the charged Higgs mass is derived at 95 % confidence level, independent of the decay branching ratio Br(H^{+/-} -> tau nu)

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Search for the standard model Higgs boson at LEP

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    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    X-ray emission from the Sombrero galaxy: discrete sources

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    We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30 kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-low indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC LF at fainter luminosities down to 1E35 erg/s. The derived index rules out a faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
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