Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Second harmonic generation (SHG) microscopy is a powerful tool for studying submicron architecture of muscles tissues. Using this technique, we show that the canonical single frequency sarcomeric SHG intensity pattern (SHG-IP) of premetamorphic xenopus tadpole tail muscles is converted to double frequency (2f) sarcomeric SHG-IP in metamorphic climax stages due to massive physiological muscle proteolysis. This conversion was found to rise from 7% in premetamorphic muscles to about 97% in fragmented muscular apoptotic bodies. Moreover a 66% conversion was also found in non-fragmented metamorphic tail muscles. Also, a strong correlation between predominant 2f sarcomeric SHG-IPs and myofibrillar misalignment is established with electron microscopy. Experimental and theoretical results demonstrate the higher sensitivity and the supra resolution power of SHG microscopy over TPEF to reveal 3D myofibrillar misalignment. From this study, we suggest that 2f sarcomeric SHG-IP could be used as signature of triad defect and disruption of excitation–contraction coupling. As the mechanism of muscle proteolysis is similar to that found in mdx mouse muscles, we further suggest that xenopus tadpole tail resorption at climax stages could be used as an alternative or complementary model of Duchene muscular dystrophy.
ISSN: 1047-8477

hal-01134174
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134174
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134174/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01134174/file/Recher%20et%20al_JSB-2015_hal.pdf
DOI : 10.1016/j.jsb.2015.03.003

Éditeur(s) : HAL CCSD
Résumé : International audience
Introduction: Diabetes mellitus results from the loss of tolerance to insulin and alters glycemia and the glycogen content. Oxidative stress and inflammation are linked to theses alterations, especially with insulin-resistance. The therapy management of diabetes includes nutritional recommendations. Several nutrients are developed to improve glycemia, oxidative stress, inflammation and glycogen content. More interestingly, ?-GOS exhibits anti-inflammatory and insulin-sensitive effects in vitro (Efstathiou and Fathi 2010) and in vivo (Boucher et al. 2003). Thus, ?-GOS is a potential functional food for the treatment of diabetes. But, less is known about the in vivo effect of ?-GOS on inflammatory, glycoxidation markers and glycogen content in diabetes. In this context, the aim of this work was to study the effect of ?-GOS developed by Sojasun technologies (from fermented soy product) compared to a synthetic ?-GOS produced by Sigma on inflammatory, glycoxidation markers and glycogen content in a streptozotocin-induced diabetic rat model. Methods: Twenty-four male Wistar streptozotocin-diabetic rat (STZ) were divided into three group: control group, supplemented with natural ?-GOS (20 mg/kg/day) group and supplemented with synthetic ?-GOS (20 mg/kg/day). The supplementation protocol duration was 8 weeks. At the end of the protocol, blood and skeletal muscle (gastrocnemius) were obtained to measure glucose , insulin, fructosamine in plasma and N-(carboxymethyl)lysine, glycogen synthase activity and glycogen content, in muscle. Results-Discussion: Diabetes was confirmed with the measure of insuline and glucose levels. All the diabetic groups had significantly higher glucose and insuline levels compared to control healthy group (data not shown). Insuline level in plasma and storage of glycogen in muscle were increased only in both ?-GOS groups. Fructosamine, TNF?and glycogen synthase activity was also decreased in the two supplemented groups (synthetic ?-GOS and natural ?-GOS). CML remained unchanged in all groups. Natural ?-OGT and synthetic ?-OGT only differed on muscular glucose level: only natural ?-OGT induced a significant decrease in muscular glucose. To conclude, our results suggest that ?-GOS alters positively glucose level, increases the glycogen content in diabetique population, improves glycemic control in the long term and decreases the inflammatory effects in streptozotocin-diabetic rat . Keywords: ?-GOS, inflammatory and glycoxidation markers, diabetes. Acknowledgment : Brittany region References Efstathiou, T. and D. Fathi. Sojasun Technologies. 2010 Boucher J et al. J Physiol Biochem. 59(3):169-73, 2003
5e congrès international de "Nutrition, Oxygen Biology and Medicine", Paris 5-7 juin 2013
Paris, France

hal-01159375
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01159375

Éditeur(s) : HAL CCSD Wiley-VCH Verlag
Résumé : International audience
Proteomic profiling plays a decisive role in the elucidation of molecular signatures representative of a specific clinical context. MuStem cell-based therapy represents a promising approach for clinical applications to cure Duchenne Muscular Dystrophy (DMD). To expand our previous studies collected in the clinically relevant DMD animal model, we decided to investigate the skeletal muscle proteome four months after systemic delivery of allogenic MuStem cells. Quantitative proteomics with isotope-coded protein labelling (ICPL) was used to compile quantitative changes in the protein expression profiles of muscle in transplanted Golden Retriever Muscular Dystrophy (GRMD) dogs as compared to GRMD dogs. A total of 492 proteins were quantified, including 25 that were overrepresented and 46 that were underrepresented after MuStem cell transplantation. Interestingly, this study demonstrates that somatic stem cell therapy impacts on the structural integrity of the muscle fascicle by acting on fibres and its connections with the extracellular matrix. We also show that cell infusion promotes protective mechanisms against oxidative stress and favours the initial phase of muscle repair. This study allows us to identify putative candidates for tissue markers that might be of great value in objectively exploring the clinical benefits resulting from our cell-based therapy for DMD.
ISSN: 1615-9853

Droits : info:eu-repo/semantics/OpenAccess
hal-01332030
https://hal.archives-ouvertes.fr/hal-01332030
https://hal.archives-ouvertes.fr/hal-01332030/document
https://hal.archives-ouvertes.fr/hal-01332030/file/Quantitative%20proteome%20profiling%20of%20dystrophic%20dog%20skeletal%20muscle_accepted.pdf
DOI : 10.1002/pmic.201600002

Éditeur(s) : HAL CCSD
Résumé : International audience
The aim was to identify patterns of work organization characteristics using data from epidemiological surveillance program of musculoskeletal disorders (MSD) implemented in the Pays de la Loire region between 2002 and 2005. A total of 3710 workers were included and completed a administered questionnaire including 16 organizational variables. Ascendant hierarchical clustering (AHC) of organizational variables and AHC of workers had identified five patterns of work organization characteristics: technical constraints and weak decision latitude; internal/external demand and mean decision latitude; weak pace constraints and mean decision latitude; internal/external demand and high decision latitude; weak pace constraints and high decision latitude. Relationships with MSD diagnosed by occupational physicians were then studied.
The specific health programs (SHP) are one of the four mechanisms of prevention planned by the Health and Safety at work Law in the province of Quebec. If the Law appoints only a responsible doctor, it is in reality Health at work teams (HWT) that develop these SHP. In this communication, based on the model of the working situation and the diagram of inter professional practices of collaboration, we study the practices of inter professional collaboration (CIP) in the HWT. The observed practices vary between independent practices, in parallel, of consultation, of dialogue and in shared services. Formalization of the teams, coordination of communication, leadership, respect and professional identities influence particularly the practices of CIP.
L’objectif était d’identifier des patterns de caractéristiques d'organisation du travail à partir des données du programme de surveillance épidémiologique des troubles musculo-squelettiques (TMS) mis en œuvre dans les Pays de la Loire entre 2002 et 2005. Au total, 3 710 salariés ont été inclus et ont répondu à un questionnaire comportant notamment 16 variables organisationnelles. Une classification ascendante hiérarchique (CAH) des variables organisationnelles puis une CAH des salariés ont permis d’identifier cinq patterns de caractéristiques d’organisation du travail : contraintes techniques et faible latitude décisionnelle ; demande interne/externe et latitude décisionnelle moyenne ; faibles contraintes de rythme et latitude décisionnelle moyenne ; demande externe/interne et forte latitude décisionnelle ; faibles contraintes de rythme et forte latitude décisionnelle. Les associations avec les TMS diagnostiqués par des médecins du travail ont ensuite été étudiées.
Actes du 50ème congrès de la Société d'Ergonomie de Langue Française
Paris, France

halshs-01307785
https://halshs.archives-ouvertes.fr/halshs-01307785

Éditeur(s) : HAL CCSD
Résumé : International audience
The main biological function of reaction wood is to act as “muscle” for trees, enabling them to control their posture and right stems when they are permanently disturbed from their set-point inclination by gravity or winds. The key property to achieve this function is the development of high mechanical stress during the formation of reaction wood cells, called “maturation strains”. Moreover, this function is basically performed through the asymmetric formation of wood (in quantity or quality) around the tree circumference. This asymmetry enables stems to bend upward or to compensate for the downward bending induced by gravity, as an asymmetric force associated to maturation strains creates a bending moment (i.e. one side of the stem “pulls” the other one). We will discuss the traits (cross sectional size and shape, wood features as G fibers or microfibril angle, eccentric growth even in usual or extreme cases as buttresses, total biomass growth and height of center of mass, stem lean and set-point angle) involved to understand how the posture control works. We will give simple formulas to estimate a “muscle efficiency” from biomechanical modeling. We will give practical methods to estimate all the involved traits, especially maturation strains from direct and indirect measurements, in peripheral functional wood or by retrospective dendrochronological analysis. Then, we will illustrate how tree stem tropisms and especially gravitropism, widely studied by physiologists, are key processes in natural ecosystems, through practical examples from tropical rainforest tree communities and regeneration of European mixed beech forests. Using the previous definition of postural control efficiency, we will show that the cross section size is rapidly a limiting factor, opposing the extreme strategies of flexible small stems, which bend easily but also right themselves quickly, to stiff big stems. Lastly, as wood in living trees ensures general storage, defence, vascular and skeletal functions, we will ask general questions about synergies and trade-offs between posture control and other functions.
Botany 2014 : new frontiers in botany
Boise, United States

hal-01627031
https://hal.archives-ouvertes.fr/hal-01627031

Éditeur(s) : HAL CCSD Springer-Verlag Berlin Heidelberg
Résumé : International audience
The main biological function of reaction wood is to act as " muscle " for trees, enabling them to control their posture. The key property to achieve this function is the development of high mechanical stress during the formation of reaction wood cells, called " maturation strains ". Actually, reaction wood formation is basically the asymmetric formation of wood around the tree circumference, with higher maturation strains on the side where reaction wood is formed than on the opposite side. This asymmetry enables stems to bend upward or to compensate for the downward bending induced by gravity. At the cross section level, the performance in this biological function is linked not only to the magnitude of this asymmetry but also to an effect of the cross-sectional size (diameter) of the stem. Eccentric growth and variations in wood mechanical stiffness are second order effects that can modify this performance. Differences in maturation strains between reaction and non-reaction woods are related to their specific cell wall structure and composition. The swelling of the cell wall matrix during maturation and the effect of microfibril angle explain the differences in maturation strains between normal and compression wood. However, this mechanism fails in explaining the high maturation shrinkage of tension wood, and several hypotheses at the molecular levels are still under debate. How trees perceive their gravitational disequilibrium is also an open question for physiologists. Integrative biomechanical modelling (from the polymer level to the cell wall, cross section and whole tree levels) enables defining key variables that explain the performance of reaction wood as a system that insures the stem motricity. Maturation strains can be precisely measured only in recently formed wood at the tree surface, but their changes during the whole tree life can also be estimated by retrospective dendrochronological analysis through structural markers of reaction wood. Lastly, wood in living trees ensures general storage, defence, vascular and skeletal functions, that ask general questions about synergies and trade-offs as the structural characteristics of reaction wood can affect all these functions.
The Biology of Reaction Wood

ISBN : 978-3-642-10813-6
hal-01452085
https://hal.archives-ouvertes.fr/hal-01452085
https://hal.archives-ouvertes.fr/hal-01452085/document
https://hal.archives-ouvertes.fr/hal-01452085/file/Chap_Gril_al_Biomechanical_action_biological_functions_2014.pdf