L'activité de l'acétylcholinestérase musculaire est-elle corrélée à la concentration du Ca 2+

International audienc

Methodological considerations for ghrelin isoforms assay in clinical evaluation in anorexia nervosa.

International audienceThe growing interest concerning the role of metabolic sensors in various eating disorders requires the implementation of a strict methodology to collect, store and process blood samples in clinical studies. In particular, measurement of isoforms of the appetite-stimulating hormone, ghrelin, has been challenging in clinical settings. Indeed the acyl ghrelin (AG) isoform is rapidly degraded into desacyl ghrelin (DAG) by blood esterases, thus optimal conditions for the conservation of AG and accurate determination of AG/DAG ratio should be used. Here, we compared different protease inhibitors (Aprotinin, PHMB, AEBSF) during blood collection, increasing delays (0-180 min) before centrifugation, plasma supplementation with various HCl concentrations, storage durations of frozen plasma (8 and 447 days) and immunoenzyme-assay procedures (one-step sequential) in healthy subjects. Optimal conditions were obtained by collecting blood with aprotinin and supplementation of plasma with 0.1 N HCl with subsequent freezing for at least 8 days and using one-step assay. Under such conditions, different patterns of secretion of ghrelin isoforms were characterized in patients with restrictive-type anorexia nervosa (AN-R) before and after nutritional recovery. We illustrate the pulsatile variations of ghrelin isoforms according to the time around a meal and hunger rates in 3 patients with AN-R. This study offers a comprehensive comparison of various conditions using selective and specific immunoassays for both ghrelin isoforms in order to optimize assay sensitivity and consistency among procedures. These assay conditions could therefore be widely used to elucidate precisely the role of ghrelin isoforms on eating behavior in physiological and pathological situations

Reconception durable de deux systèmes grandes cultures et légumiers pour réduire de moitié l’utilisation des produits phytosanitaires

Cette étude, conduite dans le cadre du dispositif DEPHY EXPE Ecophyto, sur une durée de six ans, vise à utiliser des leviers agronomiques et techniques en vue de réduire de 50 % l’utilisation des produits phytopharmaceutiques conventionnels dans deux systèmes de culture (grandes cultures et cultures légumières). Après cinq années d’expérimentation, la majorité des règles de décision ont été appliquées et la faisabilité de certains leviers mis en place a également été analysée. Ont également été identifiés des problèmes non résolus avec la technicité disponible, comme par exemple la maîtrise des bio-agresseurs du pois de conserve, le désherbage de l’oignon et la modulation des seuils de nuisibilité selon les niveaux de populations des auxiliaires. Les résultats mettent en évidence, en moyenne, des niveaux de performance moindres dans la conduite IFT50 (réduction de 50 % des IFT à l’échelle du système), avec des variations selon la culture et l’année considérée. Ces performances sont toutefois encourageantes et peuvent être améliorées afin d’optimiser l’apport de certains leviers.This study, conducted in the framework of the DEPHY EXPE Ecophyto dispositive, over a six-year period, aims at using agronomic and technical levers in order to reduce by 50 % the use of conventional phytopharmaceutical products in two cropping systems (arable and vegetable crops). After five years of experimentation, the majority of the expected technics were used and the application of some levers was analyzed. Some problems without solutions were identified, such as the control of bio-aggressors in canned peas, weeding in onion and modulation of thresholds regarding populations of auxiliaries. Results showed in average a lower performance of IFT50 conditions (reduced by 50% for treatments at the cropping system scale) that varies depending on the considered crop and year. However, the performances obtained are encouraging and can be further improved in order to optimize the benefits of certain levers