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Créteil, France

Martinot J.-B.,St Elisabeth Hospital | Mule M.,University of Catania | De Bisschop C.,University of Poitiers | Overbeek M.J.,Medical Center Haaglanden | And 3 more authors.
Journal of Applied Physiology

Acute exposure to high altitude may induce changes in carbon monoxide (CO) membrane conductance (DmCO) and capillary lung volume (Vc). Measurements were performed in 25 lowlanders at Brussels (D0), at 4,300 m after a 2- or 3-day exposure (D2,3) without preceding climbing, and 5 days later (D7,8), before and after an exercise test, under a trial with two arterial pulmonary vasodilators or a placebo. The nitric oxide (NO)/CO transfer method was used, assuming both infinite and finite values to the NO blood conductance (θNO). Doppler echocardiography provided hemodynamic data. Compared with sea level, lung diffusing capacity for CO increased by 24% at D2,3 and is returned to control at D7,8. The acute increase in lung diffusing capacity for CO resulted from increases in DmCO and Vc with finite and infinite θNO assumptions. The alveolar volume increased by 16% at D 2,3 and normalized at D7,8. The mean increase in systolic arterial pulmonary pressure at rest at D2,3 was minimal. In conclusion, the acute increase in Vc may be related to the increase in alveolar volume and to the increase in capillary pressure. Compared with the infinite θNO value, the use of a finite θNO value led to about a twofold increase in DmCO value and to a persistent increase in DmCO at D7,8 compared with D0. After exercise, DmCO decreased slightly less in subjects treated by the vasodilators, suggesting a beneficial effect on interstitial edema. Copyright © 2013 the American Physiological Society. Source

Yiou R.,Service durologie | De Laet K.,Service durologie | De Laet K.,Universitair Ziekenhuis Antwerpen | Hisano M.,Service durologie | And 4 more authors.
Journal of Sexual Medicine

Introduction. Radical prostatectomy (RP) can lead to erectile dysfunction due to surgical injury of the cavernous nerves. However, there is no simple, objective test to evaluate cavernous nerve damage caused by RP in clinical practice. Aim. To assess the value of the measurement of penile thermal and vibratory sensory thresholds to reflect cavernous nerve damage caused by RP. Methods. We included 42 consecutive patients who underwent RP with cavernous nerve sparing (laparoscopic approach, N=12) or without cavernous nerve sparing (laparoscopic, N=13; retropubic, N=11; or transperineal, N=6). Penile thermal (warm and cold) and vibratory sensory thresholds were measured twice, together with the Erectile Dysfunction Symptom Score (EDSS), 1month before and 2 months after RP. Main Outcome Measures. Penile sensory thresholds for warm, cold, and vibration sensations. Results. Penile sensory thresholds for warm (P<0.0001) and cold (P<0.0001) sensations significantly increased after non-nerve-sparing RP, but not after nerve-sparing RP. Vibration threshold only increased after transperineal non-nerve-sparing RP (P=0.031). EDSS values were significantly increased in all groups of patients 2months after surgery. Conclusions. Sensory nerve fibers carrying penile skin sensations travel with the cavernous nerves in the pelvis. Therefore, testing these sensations may help to evaluate the extent of cavernous nerve damage caused by RP. In this series, post-operative changes in penile sensory thresholds differed with the surgical technique of RP, as the cavernous nerves were preserved or not. The present results support the value of quantitative penile sensory threshold measurement to indicate RP-induced cavernous nerve injury. © 2012 International Society for Sexual Medicine. Source

Brignol A.,School of Engineering in Information and Communication Science and Technology | Al-ani T.,University of Versailles | Al-ani T.,School of Engineering in Information and Communication Science and Technology | Drouot X.,Service de Physiologie | Drouot X.,University Paris Est Creteil
Computer Methods and Programs in Biomedicine

Sleep disorders in humans have become a public health issue in recent years. Sleep can be analysed by studying the electroencephalogram (EEG) recorded during a night's sleep. Alternating between sleep-wake stages gives information related to the sleep quality and quantity since this alternating pattern is highly affected during sleep disorders. Spectral composition of EEG signals varies according to sleep stages, alternating phases of high energy associated to low frequency (deep sleep) with periods of low energy associated to high frequency (wake and light sleep). The analysis of sleep in humans is usually made on periods (epochs) of 30-s length according to the original Rechtschaffen and Kales sleep scoring manual. In this work, we propose a new phase space-based (mainly based on Poincaré plot) algorithm for automatic classification of sleep-wake states in humans using EEG data gathered over relatively short-time periods. The effectiveness of our approach is demonstrated through a series of experiments involving EEG data from seven healthy adult female subjects and was tested on epoch lengths ranging from 3-s to 30-s. The performance of our phase space approach was compared to a 2-dimensional state space approach using the power spectral (PS) in two selected human-specific frequency bands. These powers were calculated by dividing integrated spectral amplitudes at selected human-specific frequency bands. The comparison demonstrated that the phase space approach gives better performance in the case of short as well as standard 30-s epoch lengths. © 2012 Elsevier Ireland Ltd. Source

Richalet J.-P.,Service de Physiologie | Richalet J.-P.,University of Paris 13 | Letournel M.,Service de Physiologie | Salama J.,Service de Neurologie
Clinical Autonomic Research

A 63-year-old patient with Holmes-Adie syndrome presented an altered peripheral chemoreflex and suffered from high altitude pulmonary edema, suggesting an alteration of sensitive afferent fibers from the peripheral chemoreceptors. Chemo-responsiveness to hypoxia should be explored before any exposure to moderate altitude in Holmes-Adie patients. © 2010 Springer-Verlag. Source

Boerio D.,Service de Physiologie | Boerio D.,University Paris Est Creteil | Boerio D.,Institute Of Myologie | Creange A.,University Paris Est Creteil | And 5 more authors.
Journal of the Neurological Sciences

Intravenous immunoglobulin (IVIg) infusions may provide clinical benefits in multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyneuropathy (CIDP). The short delay in the clinical response to IVIg therapy is not consistent with a process of remyelination or axonal regeneration. We assessed whether or not the efficacy of IVIg infusions in MMN and CIDP could reflect changes in axonal membrane properties and nerve excitability. Ulnar motor nerve excitability was studied before and after three to five consecutive days of IVIg infusions (0.4 g/kg/day) in 10 patients with MMN, 10 patients with CIDP, and 10 neurological controls (CTRLs). Excitability recovery cycle, stimulus-response and strength-duration properties were investigated. The recovery cycle parameters (absolute and relative refractory period durations, refractoriness and supernormality) were similar in all groups and did not change after IVIg infusions. At baseline, patients with CIDP, but not with MMN, showed a reduced strength-duration time constant (chronaxie) and increased rheobase when compared to CTRLs. After IVIg infusions, strength-duration time constant remained stable in CTRLs, but decreased in patients with MMN or CIDP. Rheobase increased in the three groups after treatment. The decreased strength-duration time constant after IVIg infusions in patients with MMN or CIDP could reflect a reduction of persistent Na+ current, able to limit intraaxonal Na+ accumulation and then to produce neuroprotective effects. However, this could also reflect compensatory mechanisms that did not directly underlie the therapeutic effect. Whatever the underlying process, this result revealed that IVIgs were able to produce early nerve excitability changes. © 2010 Elsevier B.V. All rights reserved. Source

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