182 research outputs found

    An empirical approach to the nucleation of sulfuric acid droplets in the atmosphere

    Get PDF
    We use quantum mechanical evaluations of the Gibbs free energy of the hydrates of sulfuric acid, H2SO4. nH2O and (H2SO4)2 . nH2O to evaluate an empirical surface tension for sulfuric acid-water clusters containing few molecules. We use this surface tension to evaluate nucleation rates using classical heteromolecular theory. At low temperatures (T 213 K) the nucleation rates obtained with the empirical surface tensions are signifi cantly greater than those using bulk values of the surface tension. At higher temperatures the difference disappears

    The Renin Angiotensin System (RAS) mediates bifunctional growth regulation in melanoma and is a novel target for therapeutic intervention

    Get PDF
    Despite emergence of new systemic therapies, metastatic melanoma remains a challenging and often fatal form of skin cancer. The renin–angiotensin system (RAS) is a major physiological regulatory pathway controlling salt–water equilibrium, intravascular volume and blood pressure. Biological effects of the RAS are mediated by the vasoactive hormone angiotensin II (AngII) via two receptor subtypes, AT1R (encoded by AGTR1) and AT2R (encoded by AGTR2). We report decreasing expression and increasing CpG island methylation of AGTR1 in metastatic versus primary melanoma and detection in serum of methylated genomic DNA from the AGTR1 CpG island in metastatic melanoma implying that AGTR1 encodes a tumour suppressor function in melanoma. Consistent with this hypothesis, antagonism of AT1R using losartan or shRNA-mediated knockdown in melanoma cell lines expressing AGTR1 resulted in acquisition of the ability to proliferate in serum-free conditions. Conversely, ectopic expression of AGTR1 in cell lines lacking endogenous expression inhibits proliferation irrespective of the presence of AngII implying a ligand-independent suppressor function for AT1R. Treatment of melanoma cell lines expressing endogenous AT2R with either AngII or the AT2R-selective agonist Y6AII induces proliferation in serum-free conditions whereas the AT2R-specific antagonists PD123319 and EMA401 inhibit melanoma growth and angiogenesis and potentiate inhibitors of BRAF and MEK in cells with BRAF V600 mutations. Our results demonstrate that the RAS has both oncogenic and tumour suppressor functions in melanoma. Pharmacological inhibition of AT2R may provide therapeutic opportunities in melanomas expressing this receptor and AGTR1 CpG island methylation in serum may serve as a novel biomarker of metastatic melanoma

    The psychometric properties of the subscales of the GHQ-28 in a multi-ethnic maternal sample: results from the Born in Bradford cohort

    Get PDF
    Background: Poor maternal mental health can impact on children’s development and wellbeing; however, there is concern about the comparability of screening instruments administered to women of diverse ethnic origin. Methods: We used confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) to examine the subscale structure of the GHQ-28 in an ethnically diverse community cohort of pregnant women in the UK (N = 5,089). We defined five groups according to ethnicity and language of administration, and also conducted a CFA between four groups of 1,095 women who completed the GHQ-28 both during and after pregnancy. Results: After item reduction, 17 of the 28 items were considered to relate to the same four underlying concepts in each group; however, there was variation in the response to individual items by women of different ethnic origin and this rendered between group comparisons problematic. The EFA revealed that these measurement difficulties might be related to variation in the underlying concepts being measured by the factors. Conclusions: We found little evidence to recommend the use of the GHQ-28 subscales in routine clinical or epidemiological assessment of maternal women in populations of diverse ethnicity

    A rapid screening tool for psychological distress in children 3--6years old: results of a validation study.

    Get PDF
    International audienceABSTRACT: BACKGROUND: The mental health needs of young children in humanitarian contexts often remain unaddressed. The lack of a validated, rapid and simple tool for screening combined with few mental health professionals able to accurately diagnose and provide appropriate care mean that young children remain without care. Here, we present the results of the principle cross-cultural validation of the "Psychological Screening for Young Children aged 3 to 6" (PSYCAa3-6). The PSYCa 3--6 is a simple scale for children 3 to 6 years old administered by non-specialists, to screen young children in crises and thereby refer them to care if needed. METHODS: This study was conducted in Maradi, Niger. The scale was translated into Hausa, using corroboration of independent translations. A cross-cultural validation was implemented using quantitative and qualitative methods. A random sample of 580 mothers or caregivers of children 3 to 6 years old were included. The tool was psychometrically examined and diagnostic properties were assessed comparing the PSYCa 3--6 against a clinical interview as the gold standard. RESULTS: The PSYCa 3--6 Hausa version demonstrated good concurrent validity, as scores correlated with the gold standard and the Clinical Global Impression Severity Scale (CGI-S) [rho = 0.41, p-value = 0.00]. A reduction procedure was used to reduce the scale from 40 to 22 items. The test-retest reliability of the PSYCa 3--6 was found to be high (ICC 0.81, CI95% [0.68; 0.89]). In our sample, although not the purpose of this study, approximately 54 of 580 children required subsequent follow-up with a psychologist. CONCLUSIONS: To our knowledge, this is the first validation of a screening scale for children 3 to 6 years old with a cross-cultural validation component, for use in humanitarian contexts. The Hausa version of the PSYCa 3--6 is a reliable and a valuable screening tool for psychological distress. Further studies to replicate our findings and additional validations of the PSYCa 3--6 in other populations may help improve the delivery of mental health care to children

    A Micro RNA Processing Defect in Rapidly Progressing Idiopathic Pulmonary Fibrosis

    Get PDF
    BACKGROUND: Idiopathic pulmonary fibrosis exhibits differential progression from the time of diagnosis but the molecular basis for varying progression rates is poorly understood. The aim of the present study was to ascertain whether differential miRNA expression might provide one explanation for rapidly versus slowly progressing forms of IPF. METHODOLOGY AND PRINCIPAL FINDINGS: miRNA and mRNA were isolated from surgical lung biopsies from IPF patients with a clinically documented rapid or slow course of disease over the first year after diagnosis. A quantitative PCR miRNA array containing 88 of the most abundant miRNA in the human genome was used to profile lung biopsies from 9 patients with rapidly progressing IPF, 6 patients with slowly progressing IPF, and 10 normal lung biopsies. Using this approach, 11 miRNA were significantly increased and 36 were significantly decreased in rapid biopsies compared with normal biopsies. Slowly progressive biopsies exhibited 4 significantly increased miRNA and 36 significantly decreased miRNA compared with normal lung. Among the miRNA present in IPF with validated mRNA targets were those with regulatory effects on epithelial-mesenchymal transition (EMT). Five miRNA (miR-302c, miR-423-5p, miR-210, miR-376c, and miR-185) were significantly increased in rapid compared with slow IPF lung biopsies. Additional analyses of rapid biopsies and fibroblasts grown from the same biopsies revealed that the expression of AGO1 and AGO2 (essential components of the miRNA processing RISC complex) were lower compared with either slow or normal lung biopsies and fibroblasts. CONCLUSION: These findings suggest that the development and/or clinical progression of IPF might be the consequence of aberrant miRNA processing

    Undifferentiated Connective Tissue Disease-Associated Interstitial Lung Disease: Changes in Lung Function

    Get PDF
    Undifferentiated connective tissue disease (UCTD) is a distinct clinical entity that may be accompanied by interstitial lung disease (ILD). The natural history of UCTD-ILD is unknown. We hypothesized that patients with UCTD-ILD would be more likely to have improvement in lung function than those with idiopathic pulmonary fibrosis (IPF) during longitudinal follow-up. We identified subjects enrolled in the UCSF ILD cohort study with a diagnosis of IPF or UCTD. The primary outcome compared the presence or absence of a ≥5% increase in percent predicted forced vital capacity (FVC) in IPF and UCTD. Regression models were used to account for potential confounding variables. Ninety subjects were identified; 59 subjects (30 IPF, 29 UCTD) had longitudinal pulmonary function data for inclusion in the analysis. After accounting for baseline pulmonary function tests, treatment, and duration between studies, UCTD was associated with substantial improvement in FVC (odds ratio = 8.23, 95% confidence interval, 1.27–53.2; p = 0.03) during follow-up (median, 8 months) compared with IPF. Patients with UCTD-ILD are more likely to have improved pulmonary function during follow-up than those with IPF. These findings demonstrate the clinical importance of identifying UCTD in patients presenting with an “idiopathic” interstitial pneumonia

    Real-Time Imaging and Quantification of Amyloid-β Peptide Aggregates by Novel Quantum-Dot Nanoprobes

    Get PDF
    Background: Protein aggregation plays a major role in the pathogenesis of neurodegenerative disorders, such as Alzheimer’s disease. However, direct real-time imaging of protein aggregation, including oligomerization and fibrillization, has never been achieved. Here we demonstrate the preparation of fluorescent semiconductor nanocrystal (quantum dot; QD)-labeled amyloid-b peptide (QDAb) and its advanced applications. Methodology/Principal Findings: The QDAb construct retained Ab oligomer-forming ability, and the sizes of these oligomers could be estimated from the relative fluorescence intensities of the imaged spots. Both QDAb coaggregation with intact Ab42 and insertion into fibrils were detected by fluorescence microscopy. The coaggregation process was observed by real-time 3D imaging using slit-scanning confocal microscopy, which showed a typical sigmoid curve with 1.5 h in the lag-time and 12 h until saturation. Inhibition of coaggregation using an anti-Ab antibody can be observed as 3D images on a microscopic scale. Microglia ingested monomeric QDAb more significantly than oligomeric QDAb, and the ingested QDAb was mainly accumulated in the lysosome. Conclusions/Significance: These data demonstrate that QDAb is a novel nanoprobe for studying Ab oligomerization an

    20 Years Experience of TNF-Based Isolated Limb Perfusion for In-Transit Melanoma Metastases: TNF Dose Matters

    Get PDF
    Background: Approximately 5-8% of melanoma patients will develop in-transit metastases (IT-mets). Tumor necrosis factor-α (TNF) and melphalan-based isolated limb perfusion (TM-ILP) is an attractive treatment modality in melanoma patients with multiple IT-mets. This study reports on a 20 years experience and outlines the evolution and major changes since the introduction of TNF in ILP. Methods: A total of 167 TM-ILPs were performed in 148 patients, between 1991 and 2009. TM-ILPs were performed at high doses of TNF (3-4 mg) from 1991 to 2004 (n = 99) and at low doses of TNF (1-2 mg) from 2004 to 2009 (n = 68) under mild hyperthermic conditions (38°C-39.5°C.). Melphalan doses were unchanged at 10-13 mg/l (leg and arm, respectively). Characteristics for the 167 ILPs were
    corecore