70 research outputs found

    The Impact of Exercise Training and Supplemental Oxygen on Peripheral Muscles in COPD: A Randomized Controlled Trial

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    Objective: Exercise training is a cornerstone of the treatment of COPD while the related inter-individual heterogeneity in skeletal muscle dysfunction and adaptations are not yet fully understood. We set out to investigate the effects of exercise training and supplemental oxygen on functional and structural peripheral muscle adaptation. Methods: In this prospective, randomized, controlled, double-blind study, 28 patients with non-hypoxemic COPD (FEV1 45.92 ± 9.06%) performed six-weeks of combined endurance and strength training, three times a week while breathing either supplemental oxygen or medical air. The impact on exercise capacity, muscle strength and quadriceps femoris muscle cross-sectional area (CSA), was assessed by maximal cardiopulmonary exercise testing, ten-repetition maximum strength test of knee extension, and magnetic resonance imaging, respectively. Results: After exercise training, patients demonstrated a significant increase of functional capacity, aerobic capacity, exercise tolerance, quadriceps muscle strength and bilateral CSA. Supplemental oxygen affected significantly the training impact on peak work rate when compared to medical air (+0.20 ± 0.03 vs +0.12 ± 0.03 Watt/kg, p = 0.047); a significant increase in CSA (+3.9 ± 1.3 cm2, p = 0.013) was only observed in the training group using oxygen. Supplemental oxygen and exercise induced peripheral desaturation were identified as significant opposing determinants of muscle gain during this exercise training intervention, which led to different adaptations of CSA between the respective subgroups. Conclusions: The heterogenous functional and structural muscle adaptations seem determined by supplemental oxygen and exercise induced hypoxia. Indeed, supplemental oxygen may facilitate muscular training adaptations, particularly in limb muscle dysfunction, thereby contributing to the enhanced training responses on maximal aerobic and functional capacity

    International criteria for electrocardiographic interpretation in athletes: Consensus statement.

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    Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD

    Improvement of obstructive sleep apnea does not rescue left atrial enlargement in obese participants of a multimodal weight reduction program

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    The aim of our study was to investigate the effect of obstructive sleep apnea (OSA) and its weight loss related improvement on left atrial (LA) area in individuals with severe obesity participating in a multimodal weight reduction (WR) program. Participants with obesity (body mass index, BMI, 40.2 ± 7.3 kg/m2) underwent a 1-year WR program. Phenotyping was performed at baseline and after 12 months. Individuals were categorized according to their baseline apnea-hypopnea-index (AHI) into “no OSA” (AHI < 5) and “OSA” (AHI ≥ 5). From a total of 84 study participants, 69 completed the program. Average WR was 19.0 ± 15.7 kg after 12 months. Participants with obesity and OSA had a larger LA area at baseline as compared to participants with obesity but without OSA (22.4 ± 5.6 vs 18.8 ± 3.8 cm2; P = .008). Linear regression showed significant associations of AHI and BMI with LA area. In contrast, despite a significant decrease of AHI in participants with OSA as compared to those without OSA at 1 year follow up (ΔAHI was −12 ± 14) ΔLA area did not significantly differ between groups. Multivariable linear regression showed no significant association of ΔAHI or ΔBMI with ΔLA. In conclusion, the presence of obstructive sleep apnea contributes to LA enlargement on top of obesity in our study cohort. Yet, successful WR with subsequently improved OSA was not associated with an improvement of LA area

    International criteria for electrocardiographic interpretation in athletes: Consensus statement

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    Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD

    Reduction of blood pressure, plasma cholesterol, and atherosclerosis by elevated endothelial nitric oxide.

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    In the vascular system, nitric oxide is generated by endothelial NO synthase (eNOS). NO has pleiotropic effects, most of which are believed to be atheroprotective. Therefore, it has been argued that patients suffering from cardiovascular disease could benefit from an increase in eNOS activity. However, increased NO production can cause oxidative damage, cell toxicity, and apoptosis and hence could be atherogenic rather than beneficial. To study the in vivo effects of increased eNOS activity, we created transgenic mice overexpressing human eNOS. Aortic blood pressure was approximately 20 mm Hg lower in the transgenic mice compared with control mice because of lower systemic vascular resistance. The effects of eNOS overexpression on diet-induced atherosclerosis were studied in apolipoprotein E-deficient mice. Elevation of eNOS activity decreased blood pressure ( approximately 20 mm Hg) and plasma levels of cholesterol (approximately 17%), resulting in a reduction in atherosclerotic lesions by 40%. We conclude that an increase in eNOS activity is beneficial and provides protection against atherosclerosis

    Statins in the Treatment of Chronic Heart Failure: A Systematic Review

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    BACKGROUND: The efficacy of statin therapy in patients with established chronic heart failure (CHF) is a subject of much debate. METHODS AND FINDINGS: We conducted three systematic literature searches to assess the evidence supporting the prescription of statins in CHF. First, we investigated the participation of CHF patients in randomized placebo-controlled clinical trials designed to evaluate the efficacy of statins in reducing major cardiovascular events and mortality. Second, we assessed the association between serum cholesterol and outcome in CHF. Finally, we evaluated the ability of statin treatment to modify surrogate endpoint parameters in CHF. Using validated search strategies, we systematically searched PubMed for our three queries. In addition, we searched the reference lists from eligible studies, used the “see related articles” feature for key publications in PubMed, consulted the Cochrane Library, and searched the ISI Web of Knowledge for papers citing key publications. Search 1 resulted in the retrieval of 47 placebo-controlled clinical statin trials involving more than 100,000 patients. CHF patients had, however, been systematically excluded from these trials. Search 2 resulted in the retrieval of eight studies assessing the relationship between cholesterol levels and outcome in CHF patients. Lower serum cholesterol was consistently associated with increased mortality. Search 3 resulted in the retrieval of 18 studies on the efficacy of statin treatment in CHF. On the whole, these studies reported favorable outcomes for almost all surrogate endpoints. CONCLUSIONS: Since CHF patients have been systematically excluded from randomized, controlled clinical cholesterol-lowering trials, the effect of statin therapy in these patients remains to be established. Currently, two large, randomized, placebo-controlled statin trials are under way to evaluate the efficacy of statin treatment in terms of reducing clinical endpoints in CHF patients in particular

    Mission as Virtuous Practice: A Theology Of Mission Through the Lens of Virtue Ethics

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    This work uses theological virtue ethics as a guide both for critiquing various models of Christian mission and for constructing a model of mission that adequately addresses these criticisms. The first section of the dissertation (chapters one, two, and three) is devoted to an assessment of three major models of mission, which I have labeled mission as the missio Dei, mission as growth, and mission as dialogue. This assessment generates three recurring issues within the field of missiology that have remained largely unresolved: the problems of distinction, agency, and persuasion. The second half of the dissertation (chapters four, five, and the concluding chapter) involves an elucidation of a model of mission that is grounded in virtue ethics. The thesis proposed is this: Christian mission is best construed as specific activities (proclamation and gathering) that develop virtue in its practitioners, moving them toward their ultimate goal of partaking in the glory of God. My conception of mission carries with it three major goals. First, that it adequately addresses the perpetual problems of distinction, agency, and persuasion elaborated on in the critical section of the dissertation. Second, that such a model is in accordance with the depictions of Christian mission in scripture, particularly the Book of Acts. Third, that this account encourages moral reflection upon the practical activities of missionaries. Chapter four is devoted to a further explanation of these goals and an elucidation of my thesis statement, drawing significantly on the works of Thomas Aquinas and Alasdair MacIntyre. Chapter five involves an examination of the process of Christian conversion and a detailed account of the virtuous missional practice of proclamation. Finally, the concluding chapter situates the virtuous practices of mission within the broader context of a life well-lived

    Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter

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    Summary We have developed a fiber-optic strainmeter to estimate velocities and attenuation at seismic frequencies. The two main advantages of the new system compared to strain gage techniques are the higher sensitivity to deformations (moduli) and phase lags (attenuation), and that estimates are representative of bulk values. While stress-strain measurements using strain gages or ultrasonic wave propagation sample only part of the core sample, the fiber-optic strainmeter would analyze the rock sample response to an applied stress as a whole. Still, the system is under development and the first experiment on a Plexiglas sample showed that attenuation estimates are more robust than deformation estimates due to difficulties with light intensity. Initial rock measurements are made on a dolomite sample
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