L’hypotension orthostatique est une manifestation fréquente de l’atteinte neurovégétative au cours des syndromes parkinsoniens dégénératifs. La connaissance des caractéristiques fonctionnelles de la dysautonomie oriente la prise en charge thérapeutique. Évaluer la régulation neurovégétative hémodynamique chez des patients atteints de maladie de Parkinson idiopathique (MPI) et d’atrophie multisystématisée (AMS) qui ont eu des symptômes hypotensifs. Les patients AMS et MPI hospitalisés consécutivement dans le service de neurologie du CHRU de Besançon de septembre 2015 à décembre 2016 ont bénéficié d’un « Tilt-test » et d’un holter tensionnel de 24 heures (MAPA). Le « Tilt-test » était associé à l’analyse de la variabilité de fréquence cardiaque et de pression artérielle (PA), et aux dosages plasmatiques des catécholamines, de rénine, d’hormone antidiurétique. Les résultats des mesures ont permis de caractériser la dysautonomie. Parmi les 17 patients inclus (12 MPI et 5 AMS), une dysautonomie a été confirmée chez 7 patients MPI et 5 patients AMS. Une HTA de décubitus a été observée chez 9 patients MPI et 4 AMS. Les concentrations d’adrénaline étaient moindres chez les MPI que chez les AMS, en rapport avec l’effet secondaire du traitement par Lévodopa. Les PA systoliques, diastoliques et les indicateurs de régulation neurovégétative n’étaient pas statistiquement différents entre les groupes. Le « Tilt-test » couplé à la MAPA permettent d’objectiver la dysautonomie et de mettre en évidence les effets secondaires de la dopathérapie. Leur appréciation et le dépistage d’hypertension nocturne parfois associée à l’hypotension diurne permettent d’adapter les traitements pharmacologiques et non pharmacologiques pour limiter la gêne fonctionnelle due à l’instabilité hémodynamique, et donc optimiser la qualité de vie. Les explorations physiologiques de la dysautonomie sont utiles en pratique clinique pour confirmer l’existence de dysautonomie et pour adapter la prise en charge thérapeutique des syndromes parkinsoniens dégénératifs.

Este artículo de investigación tiene como objetivo realizar la medición de las variaciones de eficiencia de los países productores de biocombustibles en Latinoamérica. Se utilizó la metodología no paramétrica de análisis envolvente de datos (DEA), que permitió calcular la frontera de eficiencia de Brasil, Colombia, Argentina, Ecuador, México, Paraguay, Perú, Bolivia y Uruguay. La información analizada se obtuvo de la base de datos FAOSTAT año 2010. Los resultados mostraron el liderazgo de Perú y Brasil, con eficiencias igual a 1 en la producción de biodiésel y bioetanol. De los 9 países analizados, 7 presentaron bajos niveles de eficiencia en la producción de biocombustibles y solo uno (Paraguay) mostró tener eficiencia media en la fabricación de bioetanol.This research article has as objective to carry out the measurement of changes in efficiency of the countries biofuel producers in Latin America. The methodology was used non-parametric data envelopment analysis (DEA), allowing to compute the efficient frontier of the countries Brazil, Colombia, Argentina, Ecuador, Mexico, Paraguay, Peru, Bolivia and Uruguay. The analyzed information was obtained from FAOSTAT database of 2010. The results showed the leadership of Peru and Brazil with efficiencies equal to 1 in the production of biodiesel and bioethanol. Of the 9 countries analyzed, 7 had low levels of efficiency in the production of biofuels and only one (Paraguay), showed average efficiency in the manufacture of bioethanol.Este artigo de investigação tem por objectivo realizar a medição das variações de eficiência dos países produtores de biocombustíveis na América Latina. Utilizou-se a metodologia na paramétrica de análise envolvente de dados (DEA) que permitiu calcular a fronteira de eficiência dos países Brasil, Colômbia, Argentina, Equador, México, Paraguai, Peru, Bolívia e Uruguai. A informação analisada foi obtida pela base de dados FAOSTAT ano 2010. Os resultados mostraram a liderança do Peru e Brasil com eficiências igual a 1 na produção de biodiesel e bioetanol. Dos 9 países analisados, 7 apresentaram baixos níveis de eficiência na produção de biocombustíveis e só uma (Paraguai) mostrou ter eficiência média na fabricação de bioetanol.

Background: A dysregulation of the cardiac autonomic nervous system, studied by baroreflex sensitivity (BRS), has been shown in patients with COPD related to cigarette smoking. Several factors including hypoxemia, poor physical fitness and pulmonary hyperinflation have been suspected. Occupational COPD is frequent in dairy farmers, but patients9 characteristics might be different compared with smoking-related COPD. Objective: To examine the presence and eventually the causes of cardiac autonomic nervous dysregulation in dairy farmers with COPD. Methods: BRS was compared between 2 groups of patients with mild/moderate COPD (related either to cigarette smoking or to dairy farming) and 2 groups of healthy matched controls. Peak workload served to evaluate physical fitness. Pulmonary hyperinflation was judged by the ratio of inspiratory capacity (IC) on total lung capacity (TLC). PaO2 was measured at rest. Results: The main results are given in a Table. There was a positive correlation between PaO2 and BRS (r2=0.16; p Conclusions: Depressed baroreflex sensitivity, a characteristic of smoking-related COPD, was not found in dairy farmers with mild/moderate COPD. This difference could be due to a lower PaO2 in smoking-related COPD patients.

La BPCO est aujourd’hui un enjeu majeur de santé publique avec une prévalence de 7,5 % en France. L’évaluation la plus précise des symptômes est au cœur d’une démarche clinique rationnelle afin d’évaluer au mieux l’impact des traitements. Malgré une compréhension des mécanismes physiopathologiques de plus en plus approfondie, les options thérapeutiques restent limitées et beaucoup de patients demeurent symptomatiques. L’analyse des sous types phénotypiques et la sélection de groupes de patients permet d’envisager des thérapeutiques spécifiques, plus adaptées à chaque patient.Chronic obstructive pulmonary disease is a major public health issue, with a 7.5 % prevalence in France. Even if the main symptom, dyspnea, remains difficult to evaluate, objective clinical assessment using various scales and questionnaires is fundamental to appreciate therapeutic effects. Identification of phenotypic subsets is permitted by efforts directed at improving our knowledge on pathophysiological processes. Future innovation could spread out the development of more specific treatments.

Background. - A pilot study from our group suggests that the prevalence of chronic obstructive pulmonary disease (COPD) among dairy farmers is higher than in the general population although dairy workers are less frequently smokers.Objectives and methods. - The study presented here aims at (i) determining the prevalence of COPD in a large and representative population of dairy farmers; (ii) characterizing these patients in terms of smoking habits, dyspnoea, quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity; (iii) comparing characteristics of dairy farmers' COPD with the characteristics of COPD in patients without any occupational exposure; (iv) identifying the etiological factors of COPD in dairy farmers; and (v) constituting a cohort of COPD patients and control subjects for further longitudinal studies. Two groups of COPD patients (dairy farmers or not) and two groups of controls subjects will be selected among a representative panel of 2000 dairy workers and 2000 subjects without any occupational exposure, all aged 40 to 75 years.Expected results. - A better knowledge of the epidemiology and pathophysiology of COPD in dairy farmers should guide a specific strategy of prevention. The knowledge of the characteristics of COPD occurring in dairy farmers will help to define the therapeutic modalities that might be different compared with the therapeutic recommendations for COPD secondary to tobacco smoking. (C) 2012 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Une étude pilote suggère que la prévalence de la bronchopneumopathie chronique obstructive (BPCO) chez les producteurs laitiers dépasse celle de la population générale malgré une plus faible proportion de sujets tabagiques. L’étude a pour objectifs (1) de mesurer la prévalence de la BPCO en milieu de production laitière ; (2) de caractériser les patients en termes de tabagisme, de dyspnée, de qualité de vie, de fonction respiratoire, d’inflammation bronchique et systémique, de fonction vasculaire systémique et de capacité d’exercice ; (3) de comparer les caractéristiques des patients atteints de BPCO en milieu de production laitière avec celles d’un groupe de BPCO indemnes d’exposition professionnelle (groupe BPCO « témoin ») ; (4) de préciser les facteurs étiologiques de la BPCO en milieu de production laitière et (5) de constituer une cohorte de patients atteints de BPCO. Pour cela, un dépistage de la BPCO sera réalisé chez 2000 producteurs laitiers et 2000 sujets non exposés, tous âgés de 40 à 75 ans. Les résultats devraient (1) guider la mise en place des procédures de dépistage et de prévention de la BPCO en milieu de production laitière et (2) permettre d’optimiser la prise en charge thérapeutique de ces patients. A pilot study from our group suggests that the prevalence of chronic obstructive pulmonary disease (COPD) among dairy farmers is higher than in the general population although dairy workers are less frequently smokers. The study presented here aims at (i) determining the prevalence of COPD in a large and representative population of dairy farmers; (ii) characterizing these patients in terms of smoking habits, dyspnoea, quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity; (iii) comparing characteristics of dairy farmers’ COPD with the characteristics of COPD in patients without any occupational exposure; (iv) identifying the etiological factors of COPD in dairy farmers; and (v) constituting a cohort of COPD patients and control subjects for further longitudinal studies. Two groups of COPD patients (dairy farmers or not) and two groups of controls subjects will be selected among a representative panel of 2000 dairy workers and 2000 subjects without any occupational exposure, all aged 40 to 75 years. A better knowledge of the epidemiology and pathophysiology of COPD in dairy farmers should guide a specific strategy of prevention. The knowledge of the characteristics of COPD occurring in dairy farmers will help to define the therapeutic modalities that might be different compared with the therapeutic recommendations for COPD secondary to tobacco smoking.

BACKGROUND Moderately cold head-out water immersion stimulates both baro- and cold-receptors, and triggers complex and contradictory effects on the cardiovascular system and its autonomic nervous control. OBJECTIVES To assess the effects of water immersion and cold on cardiovascular status and related autonomic nervous activity. METHODS Hemodynamic variables and indexes of autonomic nervous activity (analysis of heart rate and blood pressure variability) were evaluated in 12 healthy subjects during 3 exposures of 20 min each in the upright position, i.e., in air (AIR, 24-25 degrees C), and during head-out water immersion at 35-36 degrees C (WIn) and 26-27 degrees C (WIc). RESULTS Plasma noradrenaline, systolic and diastolic blood pressure, and total peripheral resistances were reduced during WIn compared to AIR (263.9 +/- 39.4 vs. 492.5 +/- 35.7 pg x ml(-1), 116.5 +/- 3.7 and 65.4 +/- 1.7 mmHg vs. 140.8 +/- 4.7 and 89.8 +/- 2.8 mmHg, 14.1 +/- 1.0 vs. 16.3 +/- 0.9 mmHg x L(-1) x min, respectively) while they were increased during WIc (530.8 +/- 84.7 pg ml(-1), 148.0 +/- 7.0 mmHg, 80.8 +/- 3.0 mmHg, and 25.8 +/- 1.9 mmHg x L(-1) x min, respectively). The blood pressure variability was reduced to the same extent during WIc and Win compared to AIR. Heart rate decreased during WIn (67.8 +/- 2.7 vs. 81.2 +/- 2.7 bpm during AIR), in parallel with an increased cardiac parasympathetic activity. This pattern was strengthened during WIc (55.3 +/- 2.2 bpm). CONCLUSIONS Thermoneutral WI lowered sympathetic activity and arterial tone, while moderate whole-body skin cooling triggered vascular sympathetic activation. Conversely, both WI and cold triggered cardiac parasympathetic activation, highlighting a complex autonomic control of the cardiovascular system.

The present study was designed to assess the cardiac changes induced by cold water immersion compared with dry conditions during a prolonged hyperbaric and hyperoxic exposure (ambient pressure between 1.6 and 3 ATA and PiO(2) between 1.2 and 2.8 ATA). Ten healthy volunteers were studied during a 6 h compression in a hyperbaric chamber with immersion up to the neck in cold water while wearing wet suits. Results were compared with measurements obtained in dry conditions. Echocardiography and Doppler examinations were performed after 15 min and 5 h. Stroke volume, left atrial and left ventricular (LV) diameters remained unchanged during immersion, whereas they significantly fell during the dry session. As an index of LV contractility, percentage fractional shortening remained unchanged, in contrast to a decrease during dry experiment. Heart rate (HR) significantly decreased after 5 h, although it had not changed during the dry session. The changes in the total arterial compliance were similar during the immersed and dry sessions, with a significant decrease after 5 h. In immersed and dry conditions, cardiac output was unchanged after 15 min but decreased by almost 20% after 5 h. This decrease was related to a decrease in HR during immersion and to a decrease in stroke volume in dry conditions. The hydrostatic pressure exerted by water immersion on the systemic vessels could explain these differences. Indeed, the redistribution of blood volume towards the compliant thoracic bed may conceal a part of hypovolaemia that developed in the course of the session.

The present study was aimed at investigating the autonomic nervous system influences on the fractal organization of human heart rate during sympathovagal interactions, with special emphasize on the short-term fractal organization in heart rate variability (HRV), as assessed by the scaling exponent (alpha(1)) of the detrended fluctuation analysis. Linear and non-linear HRV analyses were used to study the sympathetic and vagal modulation of heart rate in ten healthy men (mean +/- SEM; age 26 +/- 1 years) during conditions of 1) increased sympathetic activity and vagal withdrawal (head-up tilt), 2) decreased sympathetic activity and increased vagal outflow (thermoneutral upright head-out water immersion, WIn), and 3) simultaneous activation of the two arms of the autonomic nervous activity (upright head-out immersion in cold water, WIc). Hemodynamic and linear HRV results were consistent with previous reports during similar physiological conditions. alpha(1) increased significantly during head-up tilt (from 0.71 +/- 0.13 supine to 0.90 +/- 0.15 upright) and WIn (0.86 +/- 0.10) and was significantly decreased during WIc (0.61 +/- 0.15). Thus, alpha(1) increased when the cardiac autonomic interplay was altered in a reciprocal fashion, whatever the direction of the balance change. Conversely, alpha(1) decreased during the concomitant activation of both vagal and sympathetic activities. The results of linear analysis were necessary to precisely define the direction of change in autonomic control revealed by an increase in alpha(1), while the direction of change in alpha(1) indicated whether an increased vagal activity is coupled with a decreased or increased sympathetic activation. Using both linear and non-linear analysis of HRV may increase the understanding of changes in cardiac autonomic status.

In the present study, the effects Of L-dopa treatment on cardiovascular variables and peripheral venous tone were assessed in 13 patients with Parkinson's disease (PD) with Hoehn and Yahr stages 1-4. Patients were investigated once with their regular treatment and once after 12 h of interruption Of L-dopa treatment. L-Dopa intake significantly reduced systolic and diastolic blood pressure, heart rate and plasma noradrenaline and adrenaline in both the supine and upright (60 degrees) positions. A significant reduction in stroke volume and cardiac output was also seen with L-dopa. The vascular status of the legs was assessed through thigh compression during leg weighing, a new technique developed in our laboratory. Healthy subjects were used to demonstrate that this technique provided reproducible results, consistent with those provided by strain gauge plethysmography of the calf. When using this technique in patients with PD, L-dopa caused a significant lowering of vascular tone in the lower limbs as shown, in particular, by an increase in venous distensibility. Combined with the results of the orthostatic tilting, these findings support that the treatment-linked lowering of plasma noradrenaline in patients with PD was concomitant with a significant reduction in blood pressure, heart rate and vascular tone in the lower limbs. These pharmacological side-effects contributed to reduce venous return and arterial blood pressure which, together with a lowered heart rate, worsened the haemodynamic status.

Many studies have described the physiology of water immersion (WI), whereas few have focused on post WI physiology, which faces the global water loss of the large WI diuresis. Therefore, we compared hemodynamics and vasomotor tone in 10 trained supine divers before and after two 6h sessions in dry (DY) and head out WI environments. During each exposure (DY and WI) two exercise periods (each one hour 75W ergometer cycling) started after the 3rd and 5th hours. Weight losses were significant (-2.24 +/- 0.13 kg and -2.38 +/- 0.19 kg, after DY and WI, respectively), but not different between the two conditions. Plasma volume was reduced at the end of the two conditions (-9.7 +/- 1.6% and -14.7 +/- 1.6%, respectively; p < 0.05). This post-WI decrease was deeper than post DY (p < 0.05). Cardiac output (CO) and mean arterial blood pressure were maintained after the two exposures. Plasma levels of noradrenaline, antidiuretic hormone and ANP were twofold higher after WI than after DY (p < 0.05). After DY total peripheral resistances (TPR) were increased (p < 0.05) and heart rate (HR) was reduced (p < 0.05). After WI there was a trend for a decrease in stroke volume (p = 0.07) with unchanged TPR and HR, despite more sizeable increases in plasma noradrenaline and vasopressin than after DY. We hypothesized that the higher levels of plasma natriuretic peptides after WI were likely counteracting the dehydration-required vasomotor adjustments.