242 research outputs found

    Testosterone and resistance training effects on muscle nitric oxide synthase isoforms in COPD men

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    SummaryBackgroundSkeletal muscle dysfunction contributes to exercise limitation in COPD. The role of the nitric oxide synthase (NOS) system in muscle dysfunction is ill defined. Reduced levels of endothelial NOS (eNOS) and elevated levels of inducible NOS (iNOS) in the skeletal muscle of COPD patients have been recently reported. We hypothesized that resistance exercise training (R) and/or testosterone supplementation (T) would alter the transcription and expression of the NOS isoenzymes in COPD skeletal muscle.MethodsVastus lateralis biopsies were obtained before and after a 10-week intervention in 40 men with severe COPD(age 67.7 ± 8.3, FEV1 41.4 ± 12.6% predicted): placebo + no training (P) (n = 11), placebo + resistance training (PR) (n = 8), testosterone + no training (T) (n = 11) and testosterone + resistance training (TR) (n = 10) groups. eNOS, nNOS and iNOS mRNA and protein levels were measured in each sample. mRNA and protein levels were measured using real-time PCR and enzyme-linked immunosorbant assay, respectively.ResultseNOS mRNA increased in the TR group compared to P and T groups (P < 0.001). eNOS protein was increased in TR and T groups after intervention (P < 0.05) but not in the PR group. nNOS protein increased in the PR, T, and TR groups (P < 0.05). iNOS protein decreased only in the TR group (P = 0.01).ConclusionResistance training and testosterone supplementation increased eNOS and nNOS proteins and decreased iNOS protein in the skeletal muscles of men with COPD. These changes in NO system might explain some of the favorable effects of these therapies

    Heme metabolism genes Downregulated in COPD Cachexia.

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    IntroductionCachexia contributes to increased mortality and reduced quality of life in Chronic Obstructive Pulmonary Disease (COPD) and may be associated with underlying gene expression changes. Our goal was to identify differential gene expression signatures associated with COPD cachexia in current and former smokers.MethodsWe analyzed whole-blood gene expression data from participants with COPD in a discovery cohort (COPDGene, N = 400) and assessed replication (ECLIPSE, N = 114). To approximate the consensus definition using available criteria, cachexia was defined as weight-loss &gt; 5% in the past 12 months or low body mass index (BMI) (&lt; 20 kg/m2) and 1/3 criteria: decreased muscle strength (six-minute walk distance &lt; 350 m), anemia (hemoglobin &lt; 12 g/dl), and low fat-free mass index (FFMI) (&lt; 15 kg/m2 among women and &lt; 17 kg/m2 among men) in COPDGene. In ECLIPSE, cachexia was defined as weight-loss &gt; 5% in the past 12 months or low BMI and 3/5 criteria: decreased muscle strength, anorexia, abnormal biochemistry (anemia or high c-reactive protein (&gt; 5 mg/l)), fatigue, and low FFMI. Differential gene expression was assessed between cachectic and non-cachectic subjects, adjusting for age, sex, white blood cell counts, and technical covariates. Gene set enrichment analysis was performed using MSigDB.ResultsThe prevalence of COPD cachexia was 13.7% in COPDGene and 7.9% in ECLIPSE. Fourteen genes were differentially downregulated in cachectic versus non-cachectic COPD patients in COPDGene (FDR &lt; 0.05) and ECLIPSE (FDR &lt; 0.05).DiscussionSeveral replicated genes regulating heme metabolism were downregulated among participants with COPD cachexia. Impaired heme biosynthesis may contribute to cachexia development through free-iron buildup and oxidative tissue damage

    It's more than low BMI: prevalence of cachexia and associated mortality in COPD

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    Background: Cachexia is associated with increased mortality risk among chronic obstructive pulmonary disease (COPD) patients. However, low body mass index (BMI) as opposed to cachexia is often used, particularly when calculating the BODE (BMI, Obstruction, Dyspnea and Exercise) index. For this reason, we examined mortality using a consensus definition and a weight-loss definition of cachexia among COPD cases and compared two new COPD severity indices with BODE. Methods: In the current report, the consensus definition for cachexia incorporated weight-loss > 5% in 12-months or low BMI in addition to 3/5 of decreased muscle strength, fatigue, anorexia, low FFMI and inflammation. The weight-loss definition incorporated weight-loss > 5% or weight-loss > 2% (if low BMI) in 12-months. The low BMI component in BODE was replaced with the consensus definition to create the CODE (Consensus cachexia, Obstruction, Dyspnea and Exercise) index and the weight-loss definition to create the WODE (Weight loss, Obstruction, Dyspnea and Exercise) index. Mortality was assessed using Kaplan-Meier survival and Cox Regression. Performance of models was compared using C-statistics. Results: Among 1483 COPD cases, the prevalences of cachexia by the consensus and weight-loss definitions were 4.7 and 10.4%, respectively. Cachectic patients had a greater than three-fold increased mortality by either the consensus or the weight-loss definition of cachexia independent of BMI and lung function. The CODE index predicted mortality slightly more accurately than the BODE and WODE indices. Conclusions: Cachexia is associated with increased mortality among COPD patients. Monitoring cachexia using weight-loss criteria is relatively simple and predictive of mortality among COPD cases who may be missed if only low BMI is used

    Control of bulk superconductivity via surface-bound electric fields in ion-gated niobium nitride thin films

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    Ionic gating is a very popular tool to investigate and control the electric transport and electronic ground state in a wide variety of different materials. This is due to its capability to induce large modulations of the surface charge density by means of the electric-double-layer field-effect transistor (EDL-FET) architecture, often reaching values comparable to those occurring in metallic systems. Despite finding large success in tuning the phase diagram of low-carrier density systems, including cuprates and iron-based superconductors, its applicability to conventional metallic superconductors has received significantly less attention. In my talk, I will present the work which has been carried out in my research group over several years to investigate how ionic gating can tune the properties of metallic superconductor, using niobium nitride (NbN) as an emblematic case. By fabricating EDL-FETs on NbN thin films with thickness ranging between 10 and 40 nm, we observed that small positive and negative shifts in the critical temperature Tc could be induced by changing the gate-voltage polarity, and that the magnitude of these shifts increased upon decreasing the film thickness. These findings indicated that, despite the gate-induced electric field being confined in a thin layer at the surface by electrostatic screening, the perturbation to the superconducting state extends in a region much larger than a single unit cell. Indeed, the dependence of Tc on the gate voltage and thickness could be reconciled with the Eliashberg theory of superconductivity only if this thin surface layer is coupled to the underlying, unperturbed bulk via proximity effect. We also determined that the thickness of this surface layer (i.e. the screening length of the electric field) strongly increases for large gate electric fields, reaching values of the order of 3 nm at the highest doping. Ab-initio DFT calculations reproduced these results and linked this anomalous increase of the screening length to a distortion of the pristine charge density in the material upon the application of sufficiently large electric fields. This proximity-effect-induced transformation of the quasi-2D perturbation to the electron density into a 3D bulk modification of the superconducting properties seems to be a general behavior in gated superconductors that could hinder the possibility to obtain large Tc shifts in films thicker than the screening length. Consequently, we are currently focusing on exploring the tunability of ultrathin (< 5nm-thick) NbN films in order to maximize the gate-induced Tc shift, where we developed a novel technique of self-encapsulation in ultrathin niobium oxide to ensure the full reversibility of the gate modulation in these extremely sensitive devices

    Body mass index change in gastrointestinal cancer and chronic obstructive pulmonary disease is associated with Dedicator of Cytokinesis 1

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    Background: There have been a number of candidate gene association studies of cancer cachexia-related traits, but no genome-wide association study (GWAS) has been published to date. Cachexia presents in patients with a number of complex traits, including both cancer and COPD. The objective of the current investigation was to search for a shared genetic aetiology for change in body mass index (ΔBMI) among cancer and COPD by using GWAS data in the Framingham Heart Study. Methods: A linear mixed effects model accounting for age, sex, and change in smoking status was used to calculate ΔBMI in participants over 40 years of age with three consecutive BMI time points (n = 4162). Four GWAS of ΔBMI using generalized estimating equations were performed among 1085 participants with a cancer diagnosis, 204 with gastrointestinal (GI) cancer, 112 with lung cancer, and 237 with COPD to test for association with 418 365 single-nucleotide polymorphisms (SNPs). Results: Two SNPs reached a level of genome-wide significance (P < 5 × 10−8) with ΔBMI: (i) rs41526344 within the CNTN4 gene, among COPD cases (β = 0.13, P = 4.3 × 10−8); and (ii) rs4751240 in the gene Dedicator of Cytokinesis 1 (DOCK1) among GI cancer cases (β = 0.10, P = 1.9 × 10−8). The DOCK1 SNP association replicated in the ΔBMI GWAS among COPD cases (βmeta-analyis = 0.10, Pmeta-analyis = 9.3 × 10−10). The DOCK1 gene codes for the dedicator of cytokinesis 1 protein, which has a role in myoblast fusion. Conclusions: In sum, one statistically significant common variant in the DOCK1 gene was associated with ΔBMI in GI cancer and COPD cases providing support for at least partially shared aetiology of ΔBMI in complex diseases

    Plasma leptin and insulin-like growth factor I levels during acute exacerbations of chronic obstructive pulmonary disease

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    <p>Abstract</p> <p>Background</p> <p>Recent studies have provided evidence for a link between leptin and tumor necrosis factor-alpha (TNF-α). Insulin-like growth factor I (IGF-I) mediates the metabolic effects of growth hormone (GH). The GH axis is believed to be suppressed in chronic obstructive pulmonary disease (COPD). The aim of this study is to find out whether acute exacerbations of COPD are followed by changes in plasma leptin and insulin-like growth factor I (IGF-I) levels and furthermore, whether these changes are related to systemic inflammation.</p> <p>Methods</p> <p>We measured serum leptin, IGF-I, TNF-α, interleukin 1β (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8) levels in 52 COPD patients with acute exacerbation on admission to hospital (Day 1) and two weeks later (Day 15). 25 healthy age-matched subjects served as controls. COPD patients were also divided into two subgroups (29 with chronic bronchitis and 23 with emphysema). Serum leptin and IGF-I were measured by radioimmunoassay and TNF-α, IL-1β, IL-6 and IL-8 were measured by ELISA.</p> <p>Results</p> <p>Serum leptin levels were significantly higher and serum IGF-I levels significantly lower in COPD patients on Day 1 than in healthy controls (p < 0.001). A positive correlation was observed between leptin and TNF-α on Day 1 (r = 0.620, p < 0.001). Emphysematous patients had significantly lower IGF-I levels compared to those with chronic bronchitis both on Day 1 and Day 15 (p = 0.003 and p < 0.001 respectively).</p> <p>Conclusion</p> <p>Inappropriately increased circulating leptin levels along with decreased IGF-I levels occured during acute exacerbations of COPD. Compared to chronic bronchitis, patients with emphysema had lower circulating IGF-I levels both at the onset of the exacerbation and two weeks later.</p

    Pro-inflammatory mechanisms of muscarinic receptor stimulation in airway smooth muscle

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    Background: Acetylcholine, the primary parasympathetic neurotransmitter in the airways, plays an important role in bronchoconstriction and mucus production. Recently, it has been shown that acetylcholine, by acting on muscarinic receptors, is also involved in airway inflammation and remodelling. The mechanism(s) by which muscarinic receptors regulate inflammatory responses are, however, still unknown. Methods: The present study was aimed at characterizing the effect of muscarinic receptor stimulation on cytokine secretion by human airway smooth muscle cells (hASMc) and to dissect the intracellular signalling mechanisms involved. hASMc expressing functional muscarinic M(2) and M(3) receptors were stimulated with the muscarinic receptor agonist methacholine, alone, and in combination with cigarette smoke extract (CSE), TNF-alpha, PDGF-AB or IL-1 beta. Results: Muscarinic receptor stimulation induced modest IL-8 secretion by itself, yet augmented IL-8 secretion in combination with CSE, TNF-alpha or PDGF-AB, but not with IL-1 beta. Pretreatment with GF109203X, a protein kinase C (PKC) inhibitor, completely normalized the effect of methacholine on CSE-induced IL-8 secretion, whereas PMA, a PKC activator, mimicked the effects of methacholine, inducing IL-8 secretion and augmenting the effects of CSE. Similar inhibition was observed using inhibitors of I kappa B-kinase-2 (SC514) and MEK1/2 (U0126), both downstream effectors of PKC. Accordingly, western blot analysis revealed that methacholine augmented the degradation of I kappa B alpha and the phosphorylation of ERK1/2 in combination with CSE, but not with IL-1b in hASMc. Conclusions: We conclude that muscarinic receptors facilitate CSE-induced IL-8 secretion by hASMc via PKC dependent activation of I kappa B alpha and ERK1/2. This mechanism could be of importance for COPD patients usin

    Open Data for Global Science

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    The global science system stands at a critical juncture. On the one hand, it is overwhelmed by a hidden avalanche of ephemeral bits that are central components of modern research and of the emerging ‘cyberinfrastructure’4 for e-Science.5 The rational management and exploitation of this cascade of digital assets offers boundless opportunities for research and applications. On the other hand, the ability to access and use this rising flood of data seems to lag behind, despite the rapidly growing capabilities of information and communication technologies (ICTs) to make much more effective use of those data. As long as the attention for data policies and data management by researchers, their organisations and their funders does not catch up with the rapidly changing research environment, the research policy and funding entities in many cases will perpetuate the systemic inefficiencies, and the resulting loss or underutilisation of valuable data resources derived from public investments. There is thus an urgent need for rationalised national strategies and more coherent international arrangements for sustainable access to public research data, both to data produced directly by government entities and to data generated in academic and not-for-profit institutions with public funding. In this chapter, we examine some of the implications of the ‘data driven’ research and possible ways to overcome existing barriers to accessibility of public research data. Our perspective is framed in the context of the predominantly publicly funded global science system. We begin by reviewing the growing role of digital data in research and outlining the roles of stakeholders in the research community in developing data access regimes. We then discuss the hidden costs of closed data systems, the benefits and limitations of openness as the default principle for data access, and the emerging open access models that are beginning to form digitally networked commons. We conclude by examining the rationale and requirements for developing overarching international principles from the top down, as well as flexible, common-use contractual templates from the bottom up, to establish data access regimes founded on a presumption of openness, with the goal of better capturing the benefits from the existing and future scientific data assets. The ‘Principles and Guidelines for Access to Research Data from Public Funding’ from the Organisation for Economic Cooperation and Development (OECD), reported on in another article by Pilat and Fukasaku,6 are the most important recent example of the high-level (inter)governmental approach. The common-use licenses promoted by the Science Commons are a leading example of flexible arrangements originating within the community. Finally, we should emphasise that we focus almost exclusively on the policy—the institutional, socioeconomic, and legal aspects of data access—rather than on the technical and management practicalities that are also important, but beyond the scope of this article

    Interval exercise versus continuous exercise in patients with moderate to severe chronic obstructive pulmonary disease – study protocol for a randomised controlled trial [ISRCTN11611768]

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    BACKGROUND: Physical exercise has become a cornerstone of management of chronic obstructive pulmonary disease (COPD) because it leads to clinically relevant improvements of exercise capacity and health-related quality of life (HRQL). Despite the scarcity of randomised trials directly comparing exercise protocols, current guidelines recommend high intensity continuous exercise for lower extremities as the probably most effective exercise modality. However, for patients admitted to inpatient respiratory rehabilitation programmes, it is often difficult to initiate such an exercise programme because they are severely limited by dyspnoea and leg fatigue and therefore unable to perform continuous exercise at higher intensities and for periods longer than 30 minutes. Interval exercise may be an attractive alternative for these COPD patients because it allows high intensity exercise with recovery periods. The aim of this study is to assess if interval exercise compared to high intensity continuous exercise is not of inferior effectiveness in terms of HRQL and exercise capacity improvements but associated with better exercise tolerance in patients with moderate to severe COPD at the beginning of a respiratory rehabilitation. METHODS/DESIGN: We will assign patients with moderately severe to severe COPD to either continuous exercise or interval exercise using a stratified randomisation. Patients will follow 12–15 exercise sessions during a comprehensive inpatient respiratory rehabilitation. Primary end point for effectiveness is HRQL as measured by the Chronic Respiratory Questionnaire (CRQ) two weeks after the end of rehabilitation and secondary endpoints include additional clinical outcomes such as functional exercise capacity, other HRQL measures, patients' experience of physical exercise as well as physiological measures of the effects of physical exercise such as cardiopulmonary exercise testing. Including expected drop-outs, we will need 52 patients per group to show differences corresponding to the minimal clinically important difference of the CRQ. Outcome assessors and investigators involved in data analysis will be blinded to group assignment until analyses have been carried out. DISCUSSION: Clinicians and the scientific community need evidence on the benefits and tolerance of exercise protocols available in clinical practice. The proposed trial will provide important and needed data on interval and continuous exercise for decision making in clinical practice
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