B016 Impact of a 14-night intermittent hypoxia (IH) exposure on metabolic and cardiopulmonary adaptations to exercise in healthy subjects

IntroductionModifications in exercise tolerance have been reported in obstructive sleep apnea (OSA) patients. Also specific mechanisms have been speculated related to intermittent hypoxia (IH), hypertension, obesity or metabolic disturbance associated to OSA may play a significant role in exercise limitation. In order to eliminate these confounding factors we aimed to evaluate the effects of IH exposure during 14 nights in healthy subjects on exercise capacity, cardio-respiratory response and substrate oxidation during exercise.Methods12 healthy subjects (BMI: 21.8 0.5kg.m-2) were exposed to repetitive sequences of hypoxia — re-oxygenation during sleep in a hypoxic tent with appropriate cyclic re-oxygenation (rate: 30 desaturations.h-1). Maximal and sub-maximal exercise tests were performed before and after exposure in order to investigate cardiorespiratory variables and substrate oxidation parameters.ResultsIH did not modify maximal exercise parameters (VO2, heart rate, power output) nor ventilatory threshold (VTh). But this was achieved with a significant PETCO2 reduction and a VE/VCO2 increase during both maximal (Pre IH vs Post IH at VTh and Max, p<0.05) and sub-maximal (Pre vs Post at 30 % and 60 % Pmax, p<0.05) exercise tests, indicating hyperventilation. At the 1st min recovery after submaximal exercise test, diastolic arterial blood pressure (DBP) was higher after IH exposure (Pre: 60±3 vs Post: 78±2mmHg) in favour of a delayed DBP recovery following acute exercise. During sub-maximal exercise, subjects reached maximal lipid oxidation at higher power output and presented a decreased blood lactate at the same percentage of relative power after IH exposure.ConclusionExposure to 14 days of nocturnal IH is associated with an increased ventilatory response to subsequent exercise at sea level. Furthermore, delayed DBP recovery after exercise is in favor of early IH-induced cardiovascular modifications. This observation related to muscular exercise adaptations confirms the efficacy of the model in reproducing early cardiovascular alterations occurring in OSAS. Moreover, this model induces metabolic adaptations as soon as 14 nights of exposure

Velocity defect law in the wave bottom boundary layer

This work presents a simple method based on the defect law (Nielsen, 1992) to reproduce the velocity vertical profile within the wave bottom boundary layer

Barred-beach morphological control on infragravity motion

A conceptual analysis of the coupling between bars and infragravity waves is performed combining laboratory experiments and numerical modeling. Experiments are carried out in a wave flume with a barred profile. The Boussinesq fully-nonlinear model SERR1D is validated with the laboratory data and a sensitivity analysis is performed next to study the influence on the infragravity wave dynamics of bar amplitude and location, and swash zone slope. A novel technique of incident and reflected motions separation that conserves temporal characteristics is applied. We observe that changing bar characteristics induces substantial variations in trapped energy. Interestingly, a modification of swash zone slope has a large influence on the reflected component, controlling amplitude and phase time-lag, and consequently on the resonant pattern. Variations of trapped infragravity energy induced by changes of swash zone slope reach 25 %. These changes in infragravity pattern consequently affect short-wave dynamics by modifying the breakpoint location and the breaking intensity. Our conceptual investigation suggests the existence of a morphological feedback through the action of evolving morphology on infragravity structures which modulates the action of short-waves on the morphology itself

Observations of velocities, sand concentrations, and fluxes under velocity-asymmetric oscillatory flows

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Allogeneic stem cell transplantation benefits for patients >= 60 years with acute myeloid leukemia and FLT3 internal tandem duplication : a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Intermediate-risk cytogenetic acute myeloid leukemia with an internal tandem duplication of FLT3 (FLT3-ITD) is associated with a high risk of relapse, and is now a standard indication for allogeneic stem cell transplantation. Nevertheless, most studies supporting this strategy have been performed in young patients. To address the benefit of allogeneic transplantation in the elderly, we made a selection from the European Society for Blood and Marrow Transplantation registry of de novo intermediate-risk cytogenetic acute myeloid leukemia harboring FLT3-ITD in patients aged 60 or over and transplanted from a related or unrelated donor between January 2000 and December 2015. Two hundred and ninety-one patients were identified. Most patients received a reduced-intensity conditioning (82%), while donors consisted of an unrelated donor in 161 (55%) patients. Two hundred and twelve patients received their transplantation in first remission, 37 in second remission and 42 in a more advanced stage of the disease. The 2-year leukemia-free survival rate was 56% in patients in first remission, 22% in those in second remission and 10% in patients with active disease, respectively (P= 60 with FLT3-ITD acute myeloid leukemia in first remission, similarly to current treatment recommendations for younger patients.Peer reviewe