Fatigue, Induced via Repetitive Upper-Limb Motor Tasks, Influences Trunk and Shoulder Kinematics During an Upper Limb Reaching Task in a Virtual Reality Environment

Background Efficient shoulder movement depends on the ability of central nervous system to integrate sensory information and to create an appropriate motor command. Various daily encountered factors can potentially compromise the execution of the command, such as fatigue. This study explored how fatigue influences shoulder movements during upper limb reaching. Methods Forty healthy participants were randomly assigned to one of two groups: Control or Fatigue Group. All participants completed an upper limb reaching task at baseline and post-experimental, during which they reached four targets located at 90° of shoulder abduction, 90° external rotation at 90° abduction, 120° scaption, and 120° flexion in a virtual reality environment. Following the baseline phase, the Fatigue Group completed a shoulder fatigue protocol, while Controls took a 10-minute break. Thereafter, the reaching task was repeated. Upper limb kinematic (joint angles and excursions) and spatiotemporal (speed and accuracy) data were collected during the reaching task. Electromyographic activity of the anterior and middle deltoids were also collected to characterize fatigue. Two-way repeated-measures ANOVA were performed to determine the effects of Time, Group and of the interaction between these factors. Results The Fatigue group showed decreased mean median power frequency and increased electromyographic amplitudes of the anterior deltoid (p \u3c 0.05) following the fatigue protocol. Less glenohumeral elevation, increased trunk flexion and rotation and sternoclavicular elevation were also observed in the Fatigue group (Group x Time interaction, p \u3c 0.05). The Control group improved their movement speed and accuracy in post-experimental phase, while the Fatigue group showed a decrease of movement speed and no accuracy improvement (Group x Time interaction, p \u3c 0.05). Conclusion In a fatigued state, changes in movement strategy were observed during the reaching task, including increased trunk and sternoclavicular movements and less glenohumeral movement. Performance was altered as shown by the lack of accuracy improvement over time and a decrease in movement speed in the Fatigue group

The Impact of Experimental Pain on Shoulder Movement During an Arm Elevated Reaching Task in a Virtual Reality Environment

Background: People with chronic shoulder pain have been shown to present with motor adaptations during arm movements. These adaptations may create abnormal physical stress on shoulder tendons and muscles. However, how and why these adaptations develop from the acute stage of pain is still not well-understood. Objective: To investigate motor adaptations following acute experimental shoulder pain during upper limb reaching. Methods: Forty participants were assigned to the Control or Pain group. They completed a task consisting of reaching targets in a virtual reality environment at three time points: (1) baseline (both groups pain-free), (2) experimental phase (Pain group experiencing acute shoulder pain induced by injecting hypertonic saline into subacromial space), and (3) Post experimental phase (both groups pain-free). Electromyographic (EMG) activity, kinematics, and performance data were collected. Results: The Pain group showed altered movement planning and execution as shown by a significant increased delay to reach muscles EMG peak and a loss of accuracy, compared to controls that have decreased their mean delay to reach muscles peak and improved their movement speed through the phases. The Pain group also showed protective kinematic adaptations using less shoulder elevation and elbow flexion, which persisted when they no longer felt the experimental pain. Conclusion: Acute experimental pain altered movement planning and execution, which affected task performance. Kinematic data also suggest that such adaptations may persist over time, which could explain those observed in chronic pain populations

Strategies to reduce waiting times in outpatient rehabilitation services for adults with physical disabilities : a systematic literature review

Objective: Identifying effective strategies to reduce waiting times is a crucial issue in many areas of health services. Long waiting times for rehabilitation services have been associated with numerous adverse effects in people with disabilities. The main objective of this study was to conduct a systematic literature review to assess the effectiveness of service redesign strategies to reduce waiting times in outpatient rehabilitation services for adults with physical disabilities. Methods: We conducted a systematic review, searching three databases (MEDLINE, CINAHL and EMBASE) from their inception until May 2021. We identified studies with comparative data evaluating the effect of rehabilitation services redesign strategies on reducing waiting times. The Mixed Methods Appraisal Tool was used to assess the methodological quality of the studies. A narrative synthesis was conducted. Results: Nineteen articles including various settings and populations met the selection criteria. They covered physiotherapy (n = 11), occupational therapy (n = 2), prosthetics (n = 1), exercise physiology (n = 1) and multidisciplinary (n = 4) services. The methodological quality varied (n = 10 high quality, n = 6 medium, n = 3 low); common flaws being missing information on the pre-redesign setting and characteristics of the populations. Seven articles assessed access processes or referral management strategies (e.g. self-referral), four focused on extending/modifying the roles of service providers (e.g. to triage) and eight changed the model of care delivery (e.g. mode of intervention). The different redesign strategies had positive effects on waiting times in outpatient rehabilitation services. Conclusions: This review highlights the positive effects of many service redesign strategies. These findings suggest that there are several effective strategies to choose from to reduce waiting times and help better respond to the needs of persons experiencing physical disabilities

Multiple Beneficial Health Effects of Natural Alkylglycerols from Shark Liver Oil

Alkylglycerols (alkyl-Gro) are ether lipids abundant in the liver of some elasmobranch fish species such as ratfishes and some sharks. Shark liver oil from Centrophorus squamosus (SLO), or alkyl-Gro mix from this source, have several in vivo biological activities including stimulation of hematopoiesis and immunological defences, sperm quality improvement, or anti-tumor and anti-metastasis activities. Several mechanisms are suggested for these multiple activities, resulting from incorporation of alkyl-Gro into membrane phospholipids, and lipid signaling interactions. Natural alkyl-Gro mix from SLO contains several alkyl-Gro, varying by chain length and unsaturation. Six prominent constituents of natural alkyl-Gro mix, namely 12:0, 14:0, 16:0, 18:0, 16:1 n-7, and 18:1 n-9 alkyl-Gro, were synthesized and tested for anti-tumor and anti-metastatic activities on a model of grafted tumor in mice (3LL cells). 16:1 and 18:1 alkyl-Gro showed strong activity in reducing lung metastasis number, while saturated alkyl- Gro had weaker (16:0) or no (12:0, 14:0, 18:0) effect. Multiple compounds and mechanisms are probably involved in the multiple activities of natural alkyl-Gro

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Caractérisation de la fonction in vivo de la dynéine cytoplasmique par l'utilisation de souris mutantes

La dynéine cytoplasmique est un moteur moléculaire dont la principale fonction est de transporter des mitochondries, des vésicules ou des protéines, le long des microtubules de la périphérie vers le centre de la cellule. Dans les neurones, la dynéine est responsable du transport axonal rétrograde, un processus essentiel pour la survie des neurones qui permet la communication entre les différents compartiments cellulaires. Des altérations dans le transport axonal, en particulier dans le transport axonal rétrograde, ont été retrouvées dans la plupart des maladies neurodégénératives, et pourraient être liées à un mauvais fonctionnement de la dynéine. Ce travail de thèse a permis de mettre en évidence qu une altération du transport axonal rétrograde ne conduit pas à la perte des motoneurones (Dupuis, 2009), principale caractéristique de la SLA. Cependant nous avons montré que le striatum, région impliquée dans la motricité fine des mouvements est affectée par un dysfonctionnement de la dynéine (Braunstein, 2011). Nous nous sommes intéressés aux conséquences de la perte de fonction de la dynéine au niveau périphérique, notamment dans le métabolisme lipidique (Eschbach, 2011) et dans le maintien de la fonction mitochondriale (manuscrit en cours). Enfin, nous avons étudié les mécanismes responsables de l amélioration de la survie de modèles de SLA par la mutation dynéine (Fergani, 2011). Ce travail de thèse a permis de mettre en évidence qu une altération du transport axonal rétrograde n est pas suffisante pour conduire à la perte neuronale mais qu elle s accompagne néanmoins d une atrophie du striatum.Cytoplasmic dynein is a molecular motor that drives cargoes, including whole organelles such as mitochondria, from the periphery of the cell to the perinuclear region by using microtubules as railroad tracks. In Neurons, Dynein is involved in retrograde axonal transport, which is a process required for neurons survival. Alterations in axonal transport, in both anterograde and retrograde axonal transport, were found in neurodegenerative diseases. This thesis work aims at showing that an axonal transport alteration is not sufficient to induce motor neuron disease (Dupuis, 2009), but sufficient to provoke a striatal dysfunction (Braunstein, 2010).Besides this neuronal aspect, dynein seems to be involved in lipids metabolism since dynein mutant mice present also a metabolic phenotype. Indeed, they showed an increase of fat mass in correlation with age due to a defective lipolysis associated with an increase oxidative stress (Eschbach, 2011). In parallel, we observed that dynein is required for the mitochondrial functions (manuscript ongoing). Finally, we determined the mechanisms of protective effect of dynein mutation in ALS mice (Fergani, 2011). In conclusion, this thesis work aims at showing that an axonal transport alteration is not sufficient to induce motor neuron disease, but sufficient to provoke a striatal dysfunction. Concerning the white adipose tissue, dynein seems to be involved in the lipolysis process. In addition, our results suggest that dynein is required for the mitochondrial function. Our current hypothesis is that this mitochondrial dysfunction could provoke the observed phenotype in both striatum and adipose tissue.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Counter-regulation by atorvastatin of gene modulations induced by L-NAME hypertension is associated with vascular protection

International audienc