2,224 research outputs found

    Beat-to-beat ambulatory blood pressure estimation based on random forest

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    Ambulatory blood pressure is critical in predicting some major cardiovascular events; therefore, cuff-less and noninvasive beat-to-beat ambulatory blood pressure measure-ment is of great significance. Machine-learning methods have shown the potential to derive the relationship between physio-logical signal features and ABP. In this paper, we apply random forest method to systematically explorer the inherent connections between photoplethysmography signal, electrocardiogram signal and ambulatory blood pressure. To archive this goal, 18 features were extracted from PPG and ECG signals. Several models with most significant features as inputs and beat-to-beat ABP as outputs were trained and tested on data from the Multi-Parameter Intelligent Monitoring in Intensive Care II database. Results indicate that compared with the common pulse transit time method, the RF method gives a better performance for one-hour continuous estimation of diastolic blood pressure and systolic blood pressure under both the Association for the Advancement of Medical Instrumentation and British Hyper-tension Society standard

    Inhibition of phosphodiesterase 4 modulates cytokine induction from toll like receptor activated, but not rhinovirus infected, primary human airway smooth muscle

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    Background: Virus-induced exacerbations of Chronic Obstructive Pulmonary Disease (COPD) are a significant health burden and occur even in those receiving the best current therapies. Rhinovirus (RV) infections are responsible for half of all COPD exacerbations. The mechanism by which exacerbations occur remains undefined, however it is likely to be due to virus-induced inflammation. Given that phophodiesterase 4 (PDE4) inhibitors have an anti-inflammatory effect in patients with COPD they present a potential therapy prior to, and during, these exacerbations.Methods: In the present study we investigated whether the PDE4 inhibitor piclamilast (10-6 M) could alter RV or viral mimetic (5 μg/mL of imiquimod or poly I:C) induced inflammation and RV replication in primary human airway smooth muscle cells (ASMC) and bronchial epithelial cells (HBEC). The mediators IL-6, IL-8, prostaglandin E2 and cAMP production were assayed by ELISA and RV replication was assayed by viral titration.Results: We found that in ASMCs the TLR3 agonist poly I:C induced IL-8 release was reduced while induced IL-6 release by the TLR7/8 agonist imiquimod was further increased by the presence of piclamilast. However, in RV infected ASMCs, virus replication and induced mediator release were unaltered by piclamilast, as was also found in HBECs. The novel findings of this study reveal that although PDE inhibitors may not influence RV-induced cytokine production in ASMCs and replication in either ASMCs or HBECs, they have the capacity to be anti-inflammatory during TLR activation by modulating the induction of these chemotactic cytokines.Conclusion: By extrapolating our in vitro findings to exacerbations of COPD in vivo this suggests that PDE4 inhibitors may have beneficial anti-inflammatory properties when patients are infected with bacteria or viruses other than RV. © 2013 Van Ly et al.; licensee BioMed Central Ltd

    Differential neutrophil activation in viral infections: Enhanced TLR-7/8-mediated CXCL8 release in asthma

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    © 2015 The Authors. Respirology published by Wiley Publishing Asia Pty Ltd on behalf of Asian Pacific Society of Respirology. Background and objective Respiratory viral infections are a major cause of asthma exacerbations. Neutrophils accumulate in the airways and the mechanisms that link neutrophilic inflammation, viral infections and exacerbations are unclear. This study aims to investigate anti-viral responses in neutrophils from patients with and without asthma and to investigate if neutrophils can be directly activated by respiratory viruses. Methods Neutrophils from peripheral blood from asthmatic and non-asthmatic individuals were isolated and stimulated with lipopolysaccharide (LPS) (1 μg/mL), f-met-leu-phe (fMLP) (100 nM), imiquimod (3 μg/mL), R848 (1.5 μg/mL), poly I:C (10 μg/mL), RV16 (multiplicity of infection (MOI)1), respiratory syncytial virus (RSV) (MOI1) or influenza virus (MOI1). Cell-free supernatants were collected after 1 h of neutrophil elastase (NE) and matrix metalloproteinase (MMP)-9 release, or after 24 h for CXCL8 release. Results LPS, fMLP, imiquimod and R848 stimulated the release of CXCL8, NE and MMP-9 whereas poly I:C selectively induced CXCL8 release only. R848-induced CXCL8 release was enhanced in neutrophils from asthmatics compared with non-asthmatic cells (P < 0.01). RSV triggered the release of CXCL8 and NE from neutrophils, whereas RV16 or influenza had no effect. Conclusion Neutrophils release CXCL8, NE and MMP-9 in response to viral surrogates with R848-induced CXCL8 release being specifically enhanced in asthmatic neutrophils. Toll-like receptor (TLR7/8) dysregulation may play a role in neutrophilic inflammation in viral-induced exacerbations. We aimed to investigate and compare neutrophil responses to bacterial compounds and viral mimetics as well as compare responses between people with and without asthma. We also investigated neutrophil responses to live respiratory viruses. Here we provide a novel comprehensive comparison showing differential and specific activation in innate immune cells. See Editorial, page 1

    ProtQuant: a tool for the label-free quantification of MudPIT proteomics data

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    <p>Abstract</p> <p>Background</p> <p>Effective and economical methods for quantitative analysis of high throughput mass spectrometry data are essential to meet the goals of directly identifying, characterizing, and quantifying proteins from a particular cell state. Multidimensional Protein Identification Technology (MudPIT) is a common approach used in protein identification. Two types of methods are used to detect differential protein expression in MudPIT experiments: those involving stable isotope labelling and the so-called label-free methods. Label-free methods are based on the relationship between protein abundance and sampling statistics such as peptide count, spectral count, probabilistic peptide identification scores, and sum of peptide Sequest XCorr scores (ΣXCorr). Although a number of label-free methods for protein quantification have been described in the literature, there are few publicly available tools that implement these methods. We describe ProtQuant, a Java-based tool for label-free protein quantification that uses the previously published ΣXCorr method for quantification and includes an improved method for handling missing data.</p> <p>Results</p> <p><it>ProtQuant </it>was designed for ease of use and portability for the bench scientist. It implements the ΣXCorr method for label free protein quantification from MudPIT datasets. <it>ProtQuant </it>has a graphical user interface, accepts multiple file formats, is not limited by the size of the input files, and can process any number of replicates and any number of treatments. In addition,<it>ProtQuant </it>implements a new method for dealing with missing values for peptide scores used for quantification. The new algorithm, called ΣXCorr*, uses "below threshold" peptide scores to provide meaningful non-zero values for missing data points. We demonstrate that ΣXCorr* produces an average reduction in false positive identifications of differential expression of 25% compared to ΣXCorr.</p> <p>Conclusion</p> <p><it>ProtQuant </it>is a tool for protein quantification built for multi-platform use with an intuitive user interface. <it>ProtQuant </it>efficiently and uniquely performs label-free quantification of protein datasets produced with Sequest and provides the user with facilities for data management and analysis. Importantly, <it>ProtQuant </it>is available as a self-installing executable for the Windows environment used by many bench scientists.</p

    Smoking initiation is followed by the early acquisition of epigenetic change in cervical epithelium: a longitudinal study

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    background: To prove a causal link between an epigenetic change and an environmental or behavioural risk factor for a given disease, it is first necessary to show that the onset of exposure precedes the first detection of that epigenetic change in subjects who are still free of disease. methods: Towards this end, a cohort of women aged 15–19 years, recruited soon after they first had sexual intercourse, were used to provide sequential observations on the relationship between cigarette smoking and the detection in cervical cytological samples of methylated forms of CDKN2A (p16) using nested methylation-specific polymerase chain reaction. results: Among women who remained cytologically normal and who tested negative for human papillomavirus DNA in cervical smears during follow-up, those who first started to smoke during follow-up had an increased risk of acquiring CDKN2A methylation compared with never-smokers (odds ratio=3.67; 95% confidence interval 1.09–12.33; P=0.04). conclusion: Smoking initiation is associated with the appearance of methylated forms of CDKN2A

    An Evolutionary Framework for Association Testing in Resequencing Studies

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    Sequencing technologies are becoming cheap enough to apply to large numbers of study participants and promise to provide new insights into human phenotypes by bringing to light rare and previously unknown genetic variants. We develop a new framework for the analysis of sequence data that incorporates all of the major features of previously proposed approaches, including those focused on allele counts and allele burden, but is both more general and more powerful. We harness population genetic theory to provide prior information on effect sizes and to create a pooling strategy for information from rare variants. Our method, EMMPAT (Evolutionary Mixed Model for Pooled Association Testing), generates a single test per gene (substantially reducing multiple testing concerns), facilitates graphical summaries, and improves the interpretation of results by allowing calculation of attributable variance. Simulations show that, relative to previously used approaches, our method increases the power to detect genes that affect phenotype when natural selection has kept alleles with large effect sizes rare. We demonstrate our approach on a population-based re-sequencing study of association between serum triglycerides and variation in ANGPTL4

    A single-vendor and a single-buyer integrated inventory model with ordering cost reduction dependent on lead time

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    Lead time is one of the major limits that affect planning at every stage of the supply chain system. In this paper, we study a continuous review inventory model. This paper investigates the ordering cost reductions are dependent on lead time. This study addressed two-echelon supply chain problem consisting of a single vendor and a single buyer. The main contribution of this study is that the integrated total cost of the single vendor and the single buyer integrated system is analyzed by adopting two different (linear and logarithmic) types ordering cost reductions act dependent on lead time. In both cases, we develop effective solution procedures for finding the optimal solution and then illustrative numerical examples are given to illustrate the results. The solution procedure is to determine the optimal solutions of order quantity, ordering cost, lead time and the number of deliveries from the single vendor and the single buyer in one production run, so that the integrated total cost incurred has the minimum value. Ordering cost reduction is the main aspect of the proposed model. A numerical example is given to validate the model. Numerical example solved by using Matlab software. The mathematical model is solved analytically by minimizing the integrated total cost. Furthermore, the sensitivity analysis is included and the numerical examples are given to illustrate the results. The results obtained in this paper are illustrated with the help of numerical examples. The sensitivity of the proposed model has been checked with respect to the various major parameters of the system. Results reveal that the proposed integrated inventory model is more applicable for the supply chain manufacturing system. For each case, an algorithm procedure of finding the optimal solution is developed. Finally, the graphical representation is presented to illustrate the proposed model and also include the computer flowchart in each model
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