1,267 research outputs found
DNMTs are required for delayed genome instability caused by radiation
This is an open-access article licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. The article may be redistributed, reproduced, and reused for non-commercial purposes, provided the original source is properly cited - Copyright @ 2012 Landes Bioscience.The ability of ionizing radiation to initiate genomic instability has been harnessed in the clinic where the localized delivery of controlled doses of radiation is used to induce cell death in tumor cells. Though very effective as a therapy, tumor relapse can occur in vivo and its appearance has been attributed to the radio-resistance of cells with stem cell-like features. The molecular mechanisms underlying these phenomena are unclear but there is evidence suggesting an inverse correlation between radiation-induced genomic instability and global hypomethylation. To further investigate the relationship between DNA hypomethylation, radiosensitivity and genomic stability in stem-like cells we have studied mouse embryonic stem cells containing differing levels of DNA methylation due to the presence or absence of DNA methyltransferases. Unexpectedly, we found that global levels of methylation do not determine radiosensitivity. In particular, radiation-induced delayed genomic instability was observed at the Hprt gene locus only in wild-type cells. Furthermore, absence of Dnmt1 resulted in a 10-fold increase in de novo Hprt mutation rate, which was unaltered by radiation. Our data indicate that functional DNMTs are required for radiation-induced genomic instability, and that individual DNMTs play distinct roles in genome stability. We propose that DNMTS may contribute to the acquirement of radio-resistance in stem-like cells.This study is funded by NOTE, BBSRC and the Royal Society Dorothy Hodgkin Research Fellowship
Outer zone electrons
Spatial and temporal behavior of high energy trapped electrons in outer zone of magnetospher
Diabetes status and post-load plasma glucose concentration in relation to site-specific cancer mortality: findings from the original Whitehall study
ObjectiveWhile several studies have reported on the relation of diabetes status with pancreatic cancer risk, the predictive value of this disorder for other malignancies is unclear. Methods: The Whitehall study, a 25year follow-up for mortality experience of 18,006 men with data on post-challenge blood glucose and self-reported diabetes, allowed us to address these issues. Results: There were 2158 cancer deaths at follow-up. Of the 15 cancer outcomes, diabetes status was positively associated with mortality from carcinoma of the pancreas and liver, while the relationship with lung cancer was inverse, after controlling for a range of potential covariates and mediators which included obesity and socioeconomic position. After excluding deaths occurring in the first 10years of follow-up to examine the effect of reverse causality, the magnitude of the relationships for carcinoma of the pancreas and lung was little altered, while for liver cancer it was markedly attenuated. Conclusions: In the present study, diabetes status was related to pancreatic, liver, and lung cancer risk. Cohorts with serially collected data on blood glucose and covariates are required to further examine this area
AIDS-Related Mycoses: Current Progress in the Field and Future Priorities.
Opportunistic fungal infections continue to take an unacceptably heavy toll on the most disadvantaged living with HIV-AIDS, and are a major driver for HIV-related deaths. At the second EMBO Workshop on AIDS-Related Mycoses, clinicians and scientists from around the world reported current progress and key priorities for improving outcomes from HIV-related mycoses
Novel insights into host-fungal pathogen interactions derived from live-cell imaging
Acknowledgments The authors acknowledge funding from the Wellcome Trust (080088, 086827, 075470 and 099215) including a Wellcome Trust Strategic Award for Medical Mycology and Fungal Immunology 097377 and FP7-2007–2013 grant agreement HEALTH-F2-2010-260338–ALLFUN to NARG.Peer reviewedPublisher PD
Circulating markers of arterial thrombosis and late-stage age-related macular degeneration: a case-control study.
PURPOSE: The aim of this study was to examine the relation of late-stage age-related macular degeneration (AMD) with markers of systemic atherothrombosis. METHODS: A hospital-based case-control study of AMD was undertaken in London, UK. Cases of AMD (n=81) and controls (n=77) were group matched for age and sex. Standard protocols were used for colour fundus photography and to classify AMD; physical examination included height, weight, history of or treatment for vascular-related diseases and smoking status. Blood samples were taken for measurement of fibrinogen, factor VIIc (FVIIc), factor VIIIc, prothrombin fragment F1.2 (F1.2), tissue plasminogen activator, and von Willebrand factor. Odds ratios from logistic regression analyses of each atherothrombotic marker with AMD were adjusted for age, sex, and established cardiovascular disease risk factors, including smoking, blood pressure, body mass index, and total cholesterol. RESULTS: After adjustment FVIIc and possibly F1.2 were inversely associated with the risk of AMD; per 1 standard deviation increase in these markers the odds ratio were, respectively, 0.62 (95% confidence interval 0.40, 0.95) and 0.71 (0.46, 1.09). None of the other atherothrombotic risk factors appeared to be related to AMD status. There was weak evidence that aspirin is associated with a lower risk of AMD. CONCLUSIONS: This study does not provide strong evidence of associations between AMD and systematic markers of arterial thrombosis, but the potential effects of FVIIc, and F1.2 are worthy of further investigation
New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors
We have measured the parity-violating electroweak asymmetry in the elastic
scattering of polarized electrons from the proton. The result is A = -15.05 +-
0.98(stat) +- 0.56(syst) ppm at the kinematic point theta_lab = 12.3 degrees
and Q^2 = 0.477 (GeV/c)^2. The measurement implies that the value for the
strange form factor (G_E^s + 0.392 G_M^s) = 0.025 +- 0.020 +- 0.014, where the
first error is experimental and the second arises from the uncertainties in
electromagnetic form factors. This measurement is the first fixed-target parity
violation experiment that used either a `strained' GaAs photocathode to produce
highly polarized electrons or a Compton polarimeter to continuously monitor the
electron beam polarization.Comment: 8 pages, 4 figures, Tex, elsart.cls; revised version as accepted for
Phys. Lett.
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
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
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
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