284 research outputs found

    Antimicrobial photodynamic therapy mediated by methylene blue in surfactant vehicle on periodontopathogens

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    Background: Periodontal disease (PD) is a chronic inflammatory disease caused by the presence of microbial biofilm. The aim of this study was to evaluate antimicrobial effect of antimicrobial photodynamic therapy (A-PDT) mediated by methylene blue (MB) in monomer form on A. actinomycetemcomitans and P. gingivalis. Methods: A. actinomycetemcomitans ATCC 29523 and P. gingivalis ATCC 33577 were cultured on anaerobic jars at 37 °C for 48 h, and we tested APDT in the presence of 0.25% sodium dodecyl sulfate (SDS) in phosphate-buffered saline (PBS) or in PBS alone. APDT was carried out with 100 μM MB under laser radiation (PhotolaseIII, DMC, Brazil) at ʎ =660 nm and parameters as following (P =100 mW; I =250 mW/cm2, and doses of 15, 45 and 75 J/cm2). Results: Following A-PDT, PBS groups of A. actinomycetemcomitans presented 4 Logs of microbial death after 5 min irradiation. However, there was no bacterial reduction in SDS groups. On the other hand, P. gingivalis was sensitive to APDT in the presence of 0.25% SDS with 2 logs reduction from dark toxicity. Conclusion: The presence of 0.25% SDS can lead to different responses depending on the different microbial species. © 2020 Elsevier B.V

    The K2K SciBar Detector

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    A new near detector, SciBar, for the K2K long-baseline neutrino oscillation expe riment was installed to improve the measurement of neutrino energy spectrum and to study neutrino interactions in the energy region around 1 GeV. SciBar is a 'fully active' tracking detector with fine segmentation consisting of plastic scintillator bars. The detector was constructed in summer 2003 and is taking data since October 2003. The basic design and initial performance is presented.Comment: 7 pages, 4figures, Contributed to Proceedings of the 10th Vienna Conference on Instrumentation, Vienna, February 16-21, 200

    Molecular, microbiological and clinical characterization of Clostridium difficile isolates from tertiary care hospitals in Colombia

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    In Colombia, the epidemiology and circulating genotypes of Clostridium difficile have not yet been described. Therefore, we molecularly characterized clinical isolates of C.difficile from patients with suspicion of C.difficile infection (CDI) in three tertiary care hospitals. C.difficile was isolated from stool samples by culture, the presence of A/B toxins were detected by enzyme immunoassay, cytotoxicity was tested by cell culture and the antimicrobial susceptibility determined. After DNA extraction, tcdA, tcdB and binary toxin (CDTa/CDTb) genes were detected by PCR, and PCR-ribotyping performed. From a total of 913 stool samples collected during 2013–2014, 775 were included in the study. The frequency of A/B toxins-positive samples was 9.7% (75/775). A total of 143 isolates of C.difficile were recovered from culture, 110 (76.9%) produced cytotoxic effect in cell culture, 100 (69.9%) were tcdA+/tcdB+, 11 (7.7%) tcdA-/tcdB+, 32 (22.4%) tcdA-/tcdB- and 25 (17.5%) CDTa+/CDTb+. From 37 ribotypes identified, ribotypes 591 (20%), 106 (9%) and 002 (7.9%) were the most prevalent; only one isolate corresponded to ribotype 027, four to ribotype 078 and four were new ribotypes (794,795, 804,805). All isolates were susceptible to vancomycin and metronidazole, while 85% and 7.7% were resistant to clindamycin and moxifloxacin, respectively. By multivariate analysis, significant risk factors associated to CDI were, staying in orthopedic service, exposure to third-generation cephalosporins and staying in an ICU before CDI symptoms; moreover, steroids showed to be a protector factor. These results revealed new C. difficile ribotypes and a high diversity profile circulating in Colombia different from those reported in America and European countries

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

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    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

    Isolation and Characterization of Human Trophoblast Side-Population (SP) Cells in Primary Villous Cytotrophoblasts and HTR-8/SVneo Cell Line

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    Recently, numerous studies have identified that immature cell populations including stem cells and progenitor cells can be found among “side-population” (SP) cells. Although SP cells isolated from some adult tissues have been reported elsewhere, isolation and characterization of human trophoblast SP remained to be reported. In this study, HTR-8/SVneo cells and human primary villous cytotrophoblasts (vCTBs) were stained with Hoechst 33342 and SP and non-SP (NSP) fractions were isolated using a cell sorter. A small population of SP cells was identified in HTR-8/SVneo cells and in vCTBs. SP cells expressed several vCTB-specific markers and failed to express syncytiotrophoblast (STB) or extravillous cytotrophopblast (EVT)-specific differentiation markers. SP cells formed colonies and proliferated on mouse embryonic fibroblast (MEF) feeder cells or in MEF conditioned medium supplemented with heparin/FGF2, and they also showed long-term repopulating property. SP cells could differentiate into both STB and EVT cell lineages and expressed several differentiation markers. Microarray analysis revealed that IL7R and IL1R2 were exclusively expressed in SP cells and not in NSP cells. vCTB cells sorted as positive for both IL7R and IL1R2 failed to express trophoblast differentiation markers and spontaneously differentiated into both STB and EVT in basal medium. These features shown by the SP cells suggested that IL7R and IL1R2 are available as markers to detect the SP cells and that vCTB progenitor cells and trophoblast stem cells were involved in the SP cell population

    Non-Invasive Imaging of Cysteine Cathepsin Activity in Solid Tumors Using a 64Cu-Labeled Activity-Based Probe

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    The papain family of cysteine cathepsins are actively involved in multiple stages of tumorigenesis. Because elevated cathepsin activity can be found in many types of human cancers, they are promising biomarkers that can be used to target radiological contrast agents for tumor detection. However, currently there are no radiological imaging agents available for these important molecular targets. We report here the development of positron emission tomography (PET) radionuclide-labeled probes that target the cysteine cathepsins by formation of an enzyme activity-dependent bond with the active site cysteine. These probes contain an acyloxymethyl ketone (AOMK) functional group that irreversibly labels the active site cysteine of papain family proteases attached to a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) tag for labeling with 64Cu for PET imaging studies. We performed biodistribution and microPET imaging studies in nude mice bearing subcutaneous tumors expressing various levels of cysteine cathepsin activity and found that the extent of probe uptake by tumors correlated with overall protease activity as measured by biochemical methods. Furthermore, probe signals could be reduced by pre-treatment with a general cathepsin inhibitor. We also found that inclusion of a Cy5 tag on the probe increased tumor uptake relative to probes lacking this fluorogenic dye. Overall, these results demonstrate that small molecule activity-based probes carrying radio-tracers can be used to image protease activity in living subjects

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Gene-Specific Signatures of Elevated Non-Synonymous Substitution Rates Correlate Poorly across the Plasmodium Genus

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    BACKGROUND: Comparative genome analyses of parasites allow large scale investigation of selective pressures shaping their evolution. An acute limitation to such analysis of Plasmodium falciparum is that there is only very partial low-coverage genome sequence of the most closely related species, the chimpanzee parasite P. reichenowi. However, if orthologous genes have been under similar selective pressures throughout the Plasmodium genus then positive selection on the P. falciparum lineage might be predicted to some extent by analysis of other lineages. PRINCIPAL FINDINGS: Here, three independent pairs of closely related species in different sub-generic clades (P. falciparum and P. reichenowi; P. vivax and P. knowlesi; P. yoelii and P. berghei) were compared for a set of 43 candidate ligand genes considered likely to be under positive directional selection and a set of 102 control genes for which there was no selective hypothesis. The ratios of non-synonymous to synonymous substitutions (dN/dS) were significantly elevated in the candidate ligand genes compared to control genes in each of the three clades. However, the rank order correlation of dN/dS ratios for individual candidate genes was very low, less than the correlation for the control genes. SIGNIFICANCE: The inability to predict positive selection on a gene in one lineage by identifying elevated dN/dS ratios in the orthologue within another lineage needs to be noted, as it reflects that adaptive mutations are generally rare events that lead to fixation in individual lineages. Thus it is essential to complete the genome sequences of particular species of phylogenetic importance, such as P. reichenowi

    Expression of minichromosome maintenance protein 2 as a marker for proliferation and prognosis in diffuse large B-cell lymphoma: a tissue microarray and clinico-pathological analysis

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    BACKGROUND: Minichromosome maintenance (MCM) proteins are essential for the initiation of DNA replication and have been found to be relevant markers for prognosis in a variety of tumours. The aim of this study was to assess the proliferative activity of diffuse large B-cell lymphoma (DLBCL) in tissue microarray (TMA) using one of the minichromosome maintenance proteins (Mcm2) and to explore its potential value to predict prognosis. METHODS: Immunohistochemistry for Mcm2 was performed on TMAs constructed from 302 cases of DLBCL. A monoclonal mouse antibody was used after heat induced antigen retrieval. Mcm2 expression was scored quantitatively. Positivity for Mcm2 was defined as presence of nuclear expression of Mcm2 in greater than or equal to 40 % of tumour cells. A statistical analysis was carried out of the association of Mcm2 and the clinico-pathological characteristics. RESULTS: Mcm2 expression was clearly evident in the nuclei of proliferating non-neoplastic cells and tumour cells. Positivity for Mcm2 was found in 46% (98/211) of analysable cases. A significant correlation existed between Mcm2 expression and presence of bulky disease (p = 0.003). Poor disease specific survival was observed in patients with DLBCL positive for Mcm2 expression in the univariate analysis (p = 0.0424). CONCLUSION: Mcm2 expression can be used to assess tumour proliferation and may be useful as an additional prognostic marker to refine the prediction of outcome in DLBCL
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