Frontiers in physiology
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Frontiers in physiology · Jan 2019
Submaximal Exercise Testing in Cardiovascular Rehabilitation Settings (BEST Study).
This study compared changes in measured versus predicted peak aerobic power (V̇O2peak) following cardiovascular rehabilitation (CR). Peak cardiopulmonary exercise testing (CPET) results were compared to four V̇O2peak estimation methods: the submaximal modified Bruce treadmill, Astrand-Ryhming cycle ergometer, and Chester step tests, and the Duke Activity Status Index (DASI). ⋯ Given the greater number of successful tests, no serious adverse events and acceptable mean bias, the step test appears to be a valid and safe method for assessing group-level mean changes in V̇O2peak among patients in CR. The DASI also appears to be a valid and practical questionnaire. Wide limits of agreement, however, limit their use to predict individual-level changes.
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Frontiers in physiology · Jan 2019
Internight Variability of Apnea-Hypopnea Index in Obstructive Sleep Apnea Using Ambulatory Polysomnography.
Rationale: Patients with obstructive sleep apnea (OSA) experience respiratory events with greater frequency and severity while in the supine sleeping position. Postural preference (associated with the sleep monitoring device) and "first night effect" could explain a night-to-night variability in OSA severity. Objectives: We evaluated the variability of internight polysomnography (PSG) in a large group of OSA patients and explored factors explaining this variability. ⋯ While in mild cases (5 ≤ AHI < 15) there was a significant increase in AHI related to an increase in dorsal position time during the second night, there were no changes in moderate cases (15 ≤ AHI < 30); and in severe cases (AHI ≥ 30) there was a significant decrease in both AHI and ODI during the second night independent of sleep position. Conclusion: The internight variability in AHI and ODI was related to changes in sleep structure with a contribution of indices of sleep fragmentation and dorsal position. Since the changes were greater in mild OSA cases, a second night could be routinely proposed in cases with relevant clinical uncertainty.
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Frontiers in physiology · Jan 2019
The Effects of Positive End-Expiratory Pressure on Transpulmonary Pressure and Recruitment-Derecruitment During Neurally Adjusted Ventilator Assist: A Continuous Computed Tomography Study in an Animal Model of Acute Respiratory Distress Syndrome.
Whether spontaneous breathing (SB) should be used in early acute respiratory distress syndrome (ARDS) is questioned because it may cause ventilator-induced lung injury (VILI) by tidal high strain/stress and recruitment/derecruitment (R/D). However, SB has shown beneficial effects when used appropriately. We hypothesized that high levels of positive end-expiratory pressure (PEEP), during assisted SB, would prevent tidal R/D, reducing ventilatory variation and respiratory rate while potentially increasing transpulmonary pressure (P TP). The aim was to test this hypothesis in experimental mild ARDS during continuous SB using neurally adjusted ventilator assist (NAVA) and uninterrupted computed tomography (CT) exposure. ⋯ This study shows that injurious phenomena like R/D and high P TP are present in NAVA at the two extremes of the PEEP spectrum. Willing to titrate PEEP to limit these phenomena, the physician must choose the best compromise between restraining the R/D or P TP.
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Frontiers in physiology · Jan 2019
Protective Effect of Ursolic Acid on the Intestinal Mucosal Barrier in a Rat Model of Liver Fibrosis.
Oxidative stress mediated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) plays an important role in intestinal mucosal barrier damage in various disease states. Recent evidence suggests that intestinal mucosal barrier damage and intestinal dysbiosis occur in mice with hepatic fibrosis induced by CCl4 or bile duct ligation. Another study showed that ursolic acid (UA) attenuates experimental colitis via its anti-inflammatory and antioxidant activities. ⋯ Furthermore, our results suggested that UA improved intestinal dysbiosis and the expression of the tight junction proteins Claudin 1 and Occludin in the ileum of rats. These results indicate that UA has protective effects on the intestinal mucosal barrier in rats with CCl4-induced liver fibrosis by inhibiting intestinal NOX-mediated oxidative stress. Our findings may provide a basis for further clinical studies of UA as a novel and adjuvant treatment to cure liver fibrosis.
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Frontiers in physiology · Jan 2019
Effects of Whole-Body Electromyostimulation on Strength-, Sprint-, and Jump Performance in Moderately Trained Young Adults: A Mini-Meta-Analysis of Five Homogenous RCTs of Our Work Group.
Background: Whole-body electromyostimulation (WB-EMS) gained increasing interest in sports within recent years. However, few intervention studies have examined the effects of WB-EMS on trained subjects in comparison to conventional strength training. Objective: The aim of the present mini-meta-analysis of 5 recently conducted and published randomized controlled WB-EMS trails of our work group was to evaluate potentially favorable effects of WB-EMS in comparison to conventional strength training. ⋯ Conclusion: We conclude that WB-EMS is a feasible complementary training stimulus for performance enhancement. However, additional effects on strength and power indices seem to be limited and sprint and jump-performance appear to be benefiting only slightly. Longer training periods and more frequent application times and a slightly larger stimulus could be investigated in larger samples to further elucidate beneficial effects of WB-EMS on performance parameters in athletes.