Patients' perceptions of the mechanisms underlying alcohol use problems after bariatric surgery: A qualitative systematic review.

peer reviewedAlcohol-related problems increase after bariatric surgery. The objective of this review was to synthesize findings of qualitative studies on patients' perceptions of the mechanisms leading to problematic alcohol consumption after bariatric surgery. This review followed the Joanna Briggs Institute methodology for systematic review of qualitative evidence. A comprehensive search strategy was performed in MEDLINE, PsycInfo, Scopus and Google Scholar. Study selection, data extraction and critical appraisal of included studies were undertaken by two independent reviewers. Confidence in review findings was assessed using the ConQual approach. Four studies were included in this review and led to the development of four synthesized results: (1) persistence or reappearance of psychological problems after bariatric surgery; (2) using alcohol as a coping strategy, sometimes as a replacement for food; (3) changes in the physiological response to alcohol; and (4) importance of increased information about alcohol-related risks and long-term counselling. Confidence in the synthesized results ranged from moderate to low. The results indicated postoperative problematic alcohol consumption is a complex issue, involving psychological and physiological mechanisms. Several recommendations are formulated based on the results obtained. More qualitative and quantitative studies are needed to better understand this phenomenon given the few existing qualitative studies on this topic and some divergent results found between qualitative and previous quantitative research

La myostatine

L’unique modèle murin reproduisant la myopathie centronucléaire autosomique dominante associé à une mutation du gène dynamine-2 (KI-dnm2R465W/+) reproduit la plupart des signes cliniques observés chez l’Homme, notamment une atrophie et une perte de force musculaire. La myostatine (MSTN) est un régulateur négatif majeur du muscle strié squelettique. Nous faisons l’hypothèse que l’inactivation de la mstn pourrait limiter la perte de masse et de force musculaire chez la souris KI. Afin de valider cette hypothèse, nous avons généré une souris doublement mutée (KIKO) par croisement entre souris KI et souris inactivée pour la mstn (KO-mstn). Les animaux sont suivis durant 12 mois. La force musculaire et la motricité ont significativement été altérées chez la souris KI à 1 mois. Une perte significative de masse et du volume musculaire (microIRM) a été observée à partir de 2 mois. Entre 2 et 12 mois, tous ces paramètres restent en dessous des valeurs contrôles. En comparaison de la souris KI, la souris KIKO présente une augmentation de la force musculaire ainsi qu’une capacité motrice moins affectée. De plus, la masse et le volume musculaire ont été augmentés dès l’âge de 1 mois. Les analyses moléculaires montrent que l’inactivation de la mstn entraîne une augmentation du niveau d’expression de différentes protéines impliquées dans la voie IGF1/Akt/mTOR, mais aussi une diminution du niveau d’expression de différents acteurs de la voie de dégradation ubiquitine-protéasome. L’inactivation de la mstn montre une amélioration de la masse et de la fonction musculaire chez la souris KI. À l’avenir, nous souhaitons intervenir après la mise en place de la pathologie, par injection d’une drogue anti-mstn permettant de piéger la molécule

Dynamin 2 and human diseases

International audienceDynamin 2 (DNM2) mutations cause autosomal dominant centronuclear myopathy (CNM), a rare form of congenital myopathy, and intermediate and axonal forms of Charcot-Marie-Tooth disease (CMT), a peripheral neuropathy. DNM2 is a large GTPase mainly involved in membrane trafficking through its function in the formation and release of nascent vesicles from biological membranes. DNM2 participates in clathrin-dependent and clathrin-independent endocytosis and intracellular membrane trafficking (from endosomes and Golgi apparatus). Recent studies have also implicated DNM2 in exocytosis. DNM2 belongs to the machinery responsible for the formation of vesicles and regulates the cytoskeleton providing intracellular vesicle transport. In addition, DNM2 tightly interacts with, and is involved in the regulation of actin and microtubule networks, independent from membrane trafficking processes. We summarize here the molecular, biochemical and functional data on DNM2 and discuss the possible pathophysiological mechanisms via which DNM2 mutations can lead to two distinct neuromuscular disorders

Force-Velocity-Endurance (FoVE) Model: a new in situ method for functional muscle evaluation in murine models.

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Force-Velocity-Endurance (FoVE) Model: a new in situ method for functional muscle evaluation in murine models.

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Application of a force-velocity-endurance model to in situ muscle evaluation in mouse model.

Introduction. The muscular contractile capacity is essential for human and animal movement and locomotion.Owing to their molecular structure, striated skeletal muscle cells produce a force that is a function oftheir rate of shortening. When the force production capacity of the neuromuscular system on an isolated muscleis explored, this relationship can be formulated mathematically by a rational function F(V ) [1]. Moreover, theintensity of this force decreases as a function of the duration F(t), and converges towards a characteristic criticalintensity [2]. The interaction between these two fundamental relationships has been studied only throughindependent comparisons. Considering them as two projections of a single force-velocity-time relationship [3]would make it possible to describe the force production capacities and their interactions in their entirety. Theaim of this conceptual framework is to use an integrative model to unify a new Force-Velocity-Endurance (FVE)relationship that can define muscle properties and fatigability.Methods. This new theoretical framework proposes a model that is a function of two variables (time t andvelocity V ), and seven major parameters to describe muscle properties: initial fatigue-free capacities (initialforce (F0i ), initial velocity (V0i ), initial curvature (Ci) coefficients), critical capacities (F0c , V0c , Cc) and acharacteristic time τ corresponding to the rate of capacity decline. To measure these parameters, a new 3 minall-out test with velocity variation was developed on an isokinetic ergometer (Aurora Scientific 300C) to scanthe maximum capacities of the FVE surface, on both the velocity and time dimensions. The model was testedon 12 wild-type mice (six males and sixfemales) for the tibialis anterior (TA) and gastrocnemius (GA) muscles.Results and discussion. The goodness of fit of the model from the experimental data was excellent for allmuscles (r² > 0.97). The proposed model revealed significant differences between the TA and GA muscle groups.For males, F0i , F0c and τ were higher for GA compared to TA. Considering females, F0i was significantly higherfor GA but relative F0c was higher for TA. This new model also revealed differences in the muscle capacity asa function of sexual dimorphism. For instance, F0i was sgnificanlty higher for males compared to female onlyfor TA but not GA muscles.Conclusions and perspectives. These results demonstrate that it is possible to determine the individualparameters of the proposed model (F0i , V0i , Ci, F0c , V0c , Cc and τ ) from the experimental data obtained fromthe proposed all-out test. Validating the existence of a universal FVE relationship and its theoretical foundationswould open a new conceptual framework for improving our understanding of muscle function. Although thisproject is fundamental, the practical applications resulting from this new framework could be numerous, suchas functional analysis of gene therapy in myology or the impairment of neuromuscular function in patients

Application of a force-velocity-endurance model to in situ muscle evaluation in mouse model.

Introduction. The muscular contractile capacity is essential for human and animal movement and locomotion.Owing to their molecular structure, striated skeletal muscle cells produce a force that is a function oftheir rate of shortening. When the force production capacity of the neuromuscular system on an isolated muscleis explored, this relationship can be formulated mathematically by a rational function F(V ) [1]. Moreover, theintensity of this force decreases as a function of the duration F(t), and converges towards a characteristic criticalintensity [2]. The interaction between these two fundamental relationships has been studied only throughindependent comparisons. Considering them as two projections of a single force-velocity-time relationship [3]would make it possible to describe the force production capacities and their interactions in their entirety. Theaim of this conceptual framework is to use an integrative model to unify a new Force-Velocity-Endurance (FVE)relationship that can define muscle properties and fatigability.Methods. This new theoretical framework proposes a model that is a function of two variables (time t andvelocity V ), and seven major parameters to describe muscle properties: initial fatigue-free capacities (initialforce (F0i ), initial velocity (V0i ), initial curvature (Ci) coefficients), critical capacities (F0c , V0c , Cc) and acharacteristic time τ corresponding to the rate of capacity decline. To measure these parameters, a new 3 minall-out test with velocity variation was developed on an isokinetic ergometer (Aurora Scientific 300C) to scanthe maximum capacities of the FVE surface, on both the velocity and time dimensions. The model was testedon 12 wild-type mice (six males and sixfemales) for the tibialis anterior (TA) and gastrocnemius (GA) muscles.Results and discussion. The goodness of fit of the model from the experimental data was excellent for allmuscles (r² > 0.97). The proposed model revealed significant differences between the TA and GA muscle groups.For males, F0i , F0c and τ were higher for GA compared to TA. Considering females, F0i was significantly higherfor GA but relative F0c was higher for TA. This new model also revealed differences in the muscle capacity asa function of sexual dimorphism. For instance, F0i was sgnificanlty higher for males compared to female onlyfor TA but not GA muscles.Conclusions and perspectives. These results demonstrate that it is possible to determine the individualparameters of the proposed model (F0i , V0i , Ci, F0c , V0c , Cc and τ ) from the experimental data obtained fromthe proposed all-out test. Validating the existence of a universal FVE relationship and its theoretical foundationswould open a new conceptual framework for improving our understanding of muscle function. Although thisproject is fundamental, the practical applications resulting from this new framework could be numerous, suchas functional analysis of gene therapy in myology or the impairment of neuromuscular function in patients

Does high mitochondrial efficiency carry an oxidative cost? The case of the African pygmy mouse (Mus mattheyi)

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