740 research outputs found
Staphylococcus aureus Isolates Carrying Panton-Valentine Leucocidin Genes: Their Frequency, Antimicrobial Patterns, and Association With Infectious Disease in Shahrekord City, Southwest Iran
Background: A diversity of virulence factors work together to create the pathogenicity of Staphylococcus aureus. These factors include cell surface components that promote adherence to surfaces as well as exoproteins such as Panton-Valentine leukocidin (PVL), encoded by the luk-PV genes, that invade or bypass the immune system and are toxic to the host, thereby enhancing the severity of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Objectives: The aim of this study was to determine the frequency of PVL-positive MRSA strains by real-time PCR and their antibiotic susceptibility patterns by phenotypic test. Materials and Methods: In total, 284 Staphylococcus isolates, identified by phenotypic methods from clinical samples of Shahrekord University Hospitals, Shahrekord, Iran, were tested for nuc, mecA, and PVL genes by TaqMan real-time PCR. The antibiotic susceptibility patterns of PVL-containing MRSA strains were determined via the disk diffusion method. Results: In total, 196 isolates (69%) were nuc positive (i.e., S. aureus); of those isolates, 96 (49%) were mecA positive (MRSA). Eighteen (18.8%) of the 96 MRSA positive and 3 (3%) of the 100 methicillin-susceptible Staphylococcus aureus (MSSA) strains were PVL positive. PVL-positive MRSA strains were mostly recovered from tracheal specimens. Eight PVL-positive MRSA strains were resistant to all the tested antibiotics except vancomycin. A significant correlation (P = 0.001) was found between the mecA positivity and the presence of luk-PV genes. Conclusions: Community acquired (CA)-MRSA is becoming a public health concern in many parts of the world, including Asian countries. The variable prevalence of luk-PV-positive MRSA isolates in different regions and their rather high frequency in pneumonia necessitate the application of rapid diagnostic methods such as real-time PCR to improve treatment effectiveness
Effects of dependence in high-dimensional multiple testing problems
<p>Abstract</p> <p>Background</p> <p>We consider effects of dependence among variables of high-dimensional data in multiple hypothesis testing problems, in particular the False Discovery Rate (FDR) control procedures. Recent simulation studies consider only simple correlation structures among variables, which is hardly inspired by real data features. Our aim is to systematically study effects of several network features like sparsity and correlation strength by imposing dependence structures among variables using random correlation matrices.</p> <p>Results</p> <p>We study the robustness against dependence of several FDR procedures that are popular in microarray studies, such as Benjamin-Hochberg FDR, Storey's q-value, SAM and resampling based FDR procedures. False Non-discovery Rates and estimates of the number of null hypotheses are computed from those methods and compared. Our simulation study shows that methods such as SAM and the q-value do not adequately control the FDR to the level claimed under dependence conditions. On the other hand, the adaptive Benjamini-Hochberg procedure seems to be most robust while remaining conservative. Finally, the estimates of the number of true null hypotheses under various dependence conditions are variable.</p> <p>Conclusion</p> <p>We discuss a new method for efficient guided simulation of dependent data, which satisfy imposed network constraints as conditional independence structures. Our simulation set-up allows for a structural study of the effect of dependencies on multiple testing criterions and is useful for testing a potentially new method on <it>π</it><sub>0 </sub>or FDR estimation in a dependency context.</p
Gynaecological morbidity among HIV positive pregnant women in Cameroon
<p>Abstract</p> <p>Objective</p> <p>To compare the prevalence of gynaecological conditions among HIV infected and non-infected pregnant women.</p> <p>Methods</p> <p>Two thousand and eight (2008) pregnant women were screened for HIV, lower genital tract infections and lower genital tract neoplasia at booking antenatal visit.</p> <p>Results</p> <p>About 10% (198/2008) were HIV positive. All lower genital tract infections except candidiasis were more prevalent among HIV positive compared to HIV negative women: vaginal candidiasis (36.9% vs 35.4%; <it>p </it>= 0.678), Trichomoniasis (21.2% vs 10.6%; <it>p </it>< 0.001), gonorrhoea (10.1% vs 2.5%; <it>p </it>< 0.001), bacterial vaginosis (21.2% vs 15.2%; <it>p </it>= 0.026), syphilis (35.9% vs 10.6%; <it>p </it>< 0.001), and <it>Chlamydia trachomatis </it>(38.4% vs 7.1%; <it>p </it>< 0.001). Similarly, HIV positive women more likely to have preinvasive cervical lesions: low-grade squamous intraepithelial lesion (SIL) (18.2% vs 4.4%; <it>p </it>< 0.001) and high-grade squamous intraepithelial lesion (12.1% vs 1.5%; <it>p </it>< 0.001).</p> <p>Conclusion</p> <p>We conclude that (i) sexually transmitted infections (STIs) are common in both HIV positive and HIV negative pregnant women in Cameroon, and (ii) STIs and preinvasive cervical lesions are more prevalent in HIV-infected pregnant women compared to their non-infected compatriots. We recommend routine screening and treatment of STIs during antenatal care in Cameroon and other countries with similar social profiles.</p
A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab
We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the
creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c
s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at
sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron
collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi
K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) =
(1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from
psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)
RNA interference-mediated knockdown of p21WAF1 enhances anti-tumor cell activity of oncolytic adenoviruses
The ability of oncolytic adenoviruses to replicate in and lyse cancer cells offers a potential therapeutic approach. However, selectivity and efficacy of adenovirus replication need to be improved. In this study, we present that loss of p21WAF1 promotes adenovirus replication and more effective cell killing. To test our hypothesis, we took HCT116 colon cancer cell lines carrying deletions of either p21WAF1 or p53, and infected these cell lines with wild-type adenovirus (WtD) or the oncolytic adenoviruses, ONYX-015 and Delta-24. We found that WtD, ONYX-015 and Delta-24 induced stronger cytopathic effects in HCT116 p21−/− cells compared with HCT116-WT cells. This was accompanied by increased virus production. siRNA-mediated knockdown of p21WAF1, and similarly of p27KIP1, in HCT116-WT cells also enhanced replication of and cell killing by these viruses. Furthermore, we found that TE7, an esophageal carcinoma cell line, also showed a strong cell-killing effect and virus production when p21WAF1 expression was suppressed by RNA interference before adenoviruses infection. Also, H1299 and DU-145 cells transfected with p21WAF1 siRNA showed higher virus production after ONYX-015 and Delta-24 infections. These observations suggest that p21WAF1 plays a role in mediating replication of oncolytic viruses with potential implications for adenoviral therapy of cancer
Search for New Particles Decaying to top-antitop in proton-antiproton collisions at squareroot(s)=1.8 TeV
We use 106 \ipb of data collected with the Collider Detector at Fermilab to
search for narrow-width, vector particles decaying to a top and an anti-top
quark. Model independent upper limits on the cross section for narrow, vector
resonances decaying to \ttbar are presented. At the 95% confidence level, we
exclude the existence of a leptophobic \zpr boson in a model of
topcolor-assisted technicolor with mass M_{\zpr} 480 \gev for natural
width = 0.012 M_{\zpr}, and M_{\zpr} 780 \gev for =
0.04 M_{\zpr}.Comment: The CDF Collaboration, submitted to PRL 25-Feb-200
Double Diffraction Dissociation at the Fermilab Tevatron Collider
We present results from a measurement of double diffraction dissociation in
collisions at the Fermilab Tevatron collider. The production cross
section for events with a central pseudorapidity gap of width
(overlapping ) is found to be [] at [630]
GeV. Our results are compared with previous measurements and with predictions
based on Regge theory and factorization.Comment: 10 pages, 4 figures, using RevTeX. Submitted to Physical Review
Letter
A Measurement of the Differential Dijet Mass Cross Section in p-pbar Collisions at sqrt{s}=1.8 TeV
We present a measurement of the cross section for production of two or more
jets as a function of dijet mass, based on an integrated luminosity of 86 pb^-1
collected with the Collider Detector at Fermilab. Our dijet mass spectrum is
described within errors by next-to-leading order QCD predictions using CTEQ4HJ
parton distributions, and is in good agreement with a similar measurement from
the D0 experiment.Comment: 18 pages including 2 figures and 3 tables. Submitted to Phys. Rev. D
Rapid Communication
Search for Gluinos and Scalar Quarks in Collisions at TeV using the Missing Energy plus Multijets Signature
We have performed a search for gluinos (\gls) and squarks (\sq) in a data
sample of 84 pb of \ppb collisions at = 1.8 TeV, recorded by
the Collider Detector at Fermilab, by investigating the final state of large
missing transverse energy and 3 or more jets, a characteristic signature in
R-parity-conserving supersymmetric models. The analysis has been performed
`blind', in that the inspection of the signal region is made only after the
predictions from Standard Model backgrounds have been calculated. Comparing the
data with predictions of constrained supersymmetric models, we exclude gluino
masses below 195 \gev (95% C.L.), independent of the squark mass. For the case
\msq \approx \mgls, gluino masses below 300 \gev are excluded.Comment: 7 pages, 3 figure
Search for Kaluza-Klein Graviton Emission in Collisions at TeV using the Missing Energy Signature
We report on a search for direct Kaluza-Klein graviton production in a data
sample of 84 of \ppb collisions at = 1.8 TeV, recorded
by the Collider Detector at Fermilab. We investigate the final state of large
missing transverse energy and one or two high energy jets. We compare the data
with the predictions from a -dimensional Kaluza-Klein scenario in which
gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for
=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71
TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure
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