71 research outputs found

    Comparison of Proteomic and Transcriptomic Profiles in the Bronchial Airway Epithelium of Current and Never Smokers

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    Although prior studies have demonstrated a smoking-induced field of molecular injury throughout the lung and airway, the impact of smoking on the airway epithelial proteome and its relationship to smoking-related changes in the airway transcriptome are unclear.Airway epithelial cells were obtained from never (n = 5) and current (n = 5) smokers by brushing the mainstem bronchus. Proteins were separated by one dimensional polyacrylamide gel electrophoresis (1D-PAGE). After in-gel digestion, tryptic peptides were processed via liquid chromatography/ tandem mass spectrometry (LC-MS/MS) and proteins identified. RNA from the same samples was hybridized to HG-U133A microarrays. Protein detection was compared to RNA expression in the current study and a previously published airway dataset. The functional properties of many of the 197 proteins detected in a majority of never smokers were similar to those observed in the never smoker airway transcriptome. LC-MS/MS identified 23 proteins that differed between never and current smokers. Western blotting confirmed the smoking-related changes of PLUNC, P4HB1, and uteroglobin protein levels. Many of the proteins differentially detected between never and current smokers were also altered at the level of gene expression in this cohort and the prior airway transcriptome study. There was a strong association between protein detection and expression of its corresponding transcript within the same sample, with 86% of the proteins detected by LC-MS/MS having a detectable corresponding probeset by microarray in the same sample. Forty-one proteins identified by LC-MS/MS lacked detectable expression of a corresponding transcript and were detected in <or=5% of airway samples from a previously published dataset.1D-PAGE coupled with LC-MS/MS effectively profiled the airway epithelium proteome and identified proteins expressed at different levels as a result of cigarette smoke exposure. While there was a strong correlation between protein and transcript detection within the same sample, we also identified proteins whose corresponding transcripts were not detected by microarray. This noninvasive approach to proteomic profiling of airway epithelium may provide additional insights into the field of injury induced by tobacco exposure

    Utility of total lymphocyte count as a surrogate marker for CD4 counts in HIV-1 infected children in Kenya

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    <p>Abstract</p> <p>Background</p> <p>In resource-limited settings, such as Kenya, access to CD4 testing is limited. Therefore, evaluation of less expensive laboratory diagnostics is urgently needed to diagnose immuno-suppression in children.</p> <p>Objectives</p> <p>To evaluate utility of total lymphocyte count (TLC) as surrogate marker for CD4 count in HIV-infected children.</p> <p>Methods</p> <p>This was a hospital based retrospective study conducted in three HIV clinics in Kisumu and Nairobi in Kenya. TLC, CD4 count and CD4 percent data were abstracted from hospital records of 487 antiretroviral-naïve HIV-infected children aged 1 month - 12 years.</p> <p>Results</p> <p>TLC and CD4 count were positively correlated (r = 0.66, p < 0.001) with highest correlation seen in children with severe immuno-suppression (r = 0.72, p < 0.001) and children >59 months of age (r = 0.68, p < 0.001). Children were considered to have severe immuno-suppression if they met the following WHO set CD4 count thresholds: age below 12 months (CD4 counts < 1500 cells/mm<sup>3</sup>), age 12-35 months (CD4 count < 750 cells/mm3), age 36-59 months (CD4 count < 350 cells/mm<sup>3</sup>, and age above 59 months (CD4 count < 200 cells/mm<sup>3</sup>). WHO recommended TLC threshold values for severe immuno-suppression of 4000, 3000, 2500 and 2000 cells/mm<sup>3 </sup>for age categories <12, 12-35, 36-59 and >59 months had low sensitivity of 25%, 23%, 33% and 62% respectively in predicting severe immuno-suppression using CD4 count as gold standard. Raising TLC thresholds to 7000, 6000, 4500 and 3000 cells/mm<sup>3 </sup>for each of the stated age categories increased sensitivity to 71%, 64%, 56% and 86%, with positive predictive values of 85%, 61%, 37%, 68% respectively but reduced specificity to 73%, 62%, 54% and 68% with negative predictive values of 54%, 65%, 71% and 87% respectively.</p> <p>Conclusion</p> <p>TLC is positively correlated with absolute CD4 count in children but current WHO age-specific thresholds had low sensitivity to identify severely immunosuppressed Kenyan children. Sensitivity and therefore utility of TLC to identify immuno-suppressed children may be improved by raising the TLC cut off levels across the various age categories.</p

    Upregulation of pirin expression by chronic cigarette smoking is associated with bronchial epithelial cell apoptosis

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    BACKGROUND: Cigarette smoke disrupts the protective barrier established by the airway epithelium through direct damage to the epithelial cells, leading to cell death. Since the morphology of the airway epithelium of smokers does not typically demonstrate necrosis, the most likely mechanism for epithelial cell death in response to cigarette smoke is apoptosis. We hypothesized that cigarette smoke directly up-regulates expression of apoptotic genes, which could play a role in airway epithelial apoptosis. METHODS: Microarray analysis of airway epithelium obtained by bronchoscopy on matched cohorts of 13 phenotypically normal smokers and 9 non-smokers was used to identify specific genes modulated by smoking that were associated with apoptosis. Among the up-regulated apoptotic genes was pirin (3.1-fold, p < 0.002), an iron-binding nuclear protein and transcription cofactor. In vitro studies using human bronchial cells exposed to cigarette smoke extract (CSE) and an adenovirus vector encoding the pirin cDNA (AdPirin) were performed to test the direct effect of cigarette smoke on pirin expression and the effect of pirin expression on apoptosis. RESULTS: Quantitative TaqMan RT-PCR confirmed a 2-fold increase in pirin expression in the airway epithelium of smokers compared to non-smokers (p < 0.02). CSE applied to primary human bronchial epithelial cell cultures demonstrated that pirin mRNA levels increase in a time-and concentration-dependent manner (p < 0.03, all conditions compared to controls). Overexpression of pirin, using the vector AdPirin, in human bronchial epithelial cells was associated with an increase in the number of apoptotic cells assessed by both TUNEL assay (5-fold, p < 0.01) and ELISA for cytoplasmic nucleosomes (19.3-fold, p < 0.01) compared to control adenovirus vector. CONCLUSION: These observations suggest that up-regulation of pirin may represent one mechanism by which cigarette smoke induces apoptosis in the airway epithelium, an observation that has implications for the pathogenesis of cigarette smoke-induced diseases

    The Role of Vaccine Coverage within Social Networks in Cholera Vaccine Efficacy

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    Traditional vaccine trial methods have an underlying assumption that the effect of a vaccine is the same throughout the trial area. There are, however, many spatial and behavioral factors that alter the rates of contact among infectious and susceptible individuals and result in different efficacies across a population. We reanalyzed data from a field trial in Bangladesh to ascertain whether there is evidence of indirect protection from cholera vaccines when vaccination rates are high in an individual's social network.We analyzed the first year of surveillance data from a placebo-controlled trial of B subunit-killed whole-cell and killed whole-cell-only oral cholera vaccines in children and adult women in Bangladesh. We calculated whether there was an inverse trend for the relation between the level of vaccine coverage in an individual's social network and the incidence of cholera in individual vaccine recipients or placebo recipients after controlling for potential confounding variables.Using bari-level social network ties, we found incidence rates of cholera among placebo recipients were inversely related to levels of vaccine coverage (5.28 cases per 1000 in the lowest quintile vs 3.27 cases per 1000 in the highest quintile; p = 0.037 for trend). Receipt of vaccine by an individual and the level of vaccine coverage of the individual's social network were independently related to a reduced risk of cholera.Findings indicate that progressively higher levels of vaccine coverage in bari-level social networks can lead to increasing levels of indirect protection of non-vaccinated individuals and could also lead to progressively higher levels of total protection of vaccine recipients

    Pre-ART Levels of Inflammation and Coagulation Markers Are Strong Predictors of Death in a South African Cohort with Advanced HIV Disease

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    BACKGROUND: Levels of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and D-dimer predict mortality in HIV patients on antiretroviral therapy (ART) with relatively preserved CD4+ T cell counts. We hypothesized that elevated pre-ART levels of these markers among patients with advanced HIV would be associated with an increased risk of death following the initiation of ART. METHODS: Pre-ART plasma from patients with advanced HIV in South Africa was used to measure hsCRP, IL-6 and D-dimer. Using a nested case-control study design, the biomarkers were measured for 187 deaths and two controls matched on age, sex, clinical site, follow-up time and CD4+ cell counts. Odds ratios were estimated using conditional logistic regression. In addition, for a random sample of 100 patients, biomarkers were measured at baseline and 6 months following randomization to determine whether ART altered their levels. RESULTS: Median baseline biomarkers levels for cases and controls, respectively, were 11.25 vs. 3.6 mg/L for hsCRP, 1.41 vs. 0.98 mg/L for D-dimer, and 9.02 vs. 4.20 pg/mL for IL-6 (all p<0.0001). Adjusted odds ratios for the highest versus lowest quartile of baseline biomarker levels were 3.5 (95% CI: 1.9-6.7) for hsCRP, 2.6 (95%CI 1.4-4.9) for D-dimer, and 3.8 (95% CI: 1.8-7.8) for IL-6. These associations were stronger for deaths that occurred more proximal to the biomarker measurements. Levels of D-dimer and IL-6, but not hsCRP, were significantly lower at month 6 after commencing ART compared to baseline (p<0.0001). CONCLUSIONS: Among patients with advanced HIV disease, elevated pre-ART levels of hsCRP, IL-6 and D-dimer are strongly associated with early mortality after commencing ART. Elevated levels of inflammatory and coagulation biomarkers may identify patients who may benefit from aggressive clinical monitoring after commencing ART. Further investigation of strategies to reduce biomarkers of inflammation and coagulation in patients with advanced HIV disease is warranted. TRIAL REGISTRATION: Parent study: ClinicalTrials.gov NCT00342355

    Did Corporate Governance Compliance Have an Impact on Auditor Selection and Quality? Evidence From FTSE 350

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This paper examines the possible effects of corporate governance (GC) on audit quality (AQ) among the FTSE 350 companies. Using a sample of 180 companies from 2012 to 2017 (i.e., 1080 firm-year observations) a binary logistic model has been employed to investigate the CG-AQ nexus. This analysis was supported by conducting a probit logistic model as a sensitivity analysis. Our findings are associative of a heterogeneous impact of CG on AQ post the implementation of the 2012 CG reforms in the UK. For example, although institutional ownership and management ownership are positively associated with auditor selection and AQ, board independence, non-executive directors and audit committee are not attributed to AQ in the UK. This implies that corporate compliance with good CG practices has a limited impact on the decision to select a Big4 auditor in the UK. Despite the limitations of our study, we hope it can motivate further investigations in this area
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