Relaix F.,University Pierre and Marie Curie |
Relaix F.,French Institute of Health and Medical Research |
Relaix F.,Institute Of Myologie |
Zammit P.S.,King's College London
Development (Cambridge) | Year: 2012
Following their discovery in 1961, it was speculated that satellite cells were dormant myoblasts, held in reserve until required for skeletal muscle repair. Evidence for this accumulated over the years, until the link between satellite cells and the myoblasts that appear during muscle regeneration was finally established. Subsequently, it was demonstrated that, when grafted, satellite cells could also self-renew, conferring on them the coveted status of 'stem cell'. The emergence of other cell types with myogenic potential, however, questioned the precise role of satellite cells. Here, we review recent recombination-based studies that have furthered our understanding of satellite cell biology. The clear consensus is that skeletal muscle does not regenerate without satellite cells, confirming their pivotal and non-redundant role. © 2012. Published by The Company of Biologists Ltd.
Benveniste O.,University Pierre and Marie Curie |
Benveniste O.,Institute Of Myologie |
Stenzel W.,Charité - Medical University of Berlin |
Hilton-Jones D.,John Radcliffe Hospital |
And 4 more authors.
Acta Neuropathologica | Year: 2015
Sporadic inclusion body myositis (sIBM) is the most frequently acquired myopathy in patients over 50 years of age. It is imperative that neurologists and rheumatologists recognize this disorder which may, through clinical and pathological similarities, mimic other myopathies, especially polymyositis. Whereas polymyositis responds to immunosuppressant drug therapy, sIBM responds poorly, if at all. Controversy reigns as to whether sIBM is primarily an inflammatory or a degenerative myopathy, the distinction being vitally important in terms of directing research for effective specific therapies. We review here the pros and the cons for the respective hypotheses. A possible scenario, which our experience leads us to favour, is that sIBM may start with inflammation within muscle. The rush of leukocytes attracted by chemokines and cytokines may induce fibre injury and HLA-I overexpression. If the protein degradation systems are overloaded (possibly due to genetic predisposition, particular HLA-I subtypes or ageing), amyloid and other protein deposits may appear within muscle fibres, reinforcing the myopathic process in a vicious circle. © 2015, The Author(s).
Finsterer J.,Krankenanstalt Rudolfstiftung |
Stollberger C.,Krankenanstalt Rudolfstiftung |
Wahbi K.,Institute Of Myologie
Cardiovascular Pathology | Year: 2013
According to the American Heart Association, cardiomyopathies are classified as primary (solely or predominantly confined to heart muscle), secondary (those showing pathological myocardial involvement as part of a neuromuscular disorder) and those in which cardiomyopathy is the first/predominant manifestation of a neuromuscular disorder. Cardiomyopathies may be further classified as hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, or unclassified cardiomyopathy (noncompaction, Takotsubo-cardiomyopathy). This review focuses on secondary cardiomyopathies and those in which cardiomyopathy is the predominant manifestation of a myopathy. Any of them may cause neurological disease, and any of them may be a manifestation of a neurological disorder. Neurological disease most frequently caused by cardiomyopathies is ischemic stroke, followed by transitory ischemic attack, syncope, or vertigo. Neurological disease, which most frequently manifests with cardiomyopathies are the neuromuscular disorders. Most commonly associated with cardiomyopathies are muscular dystrophies, myofibrillar myopathies, congenital myopathies and metabolic myopathies. Management of neurological disease caused by cardiomyopathies is not at variance from the same neurological disorders due to other causes. Management of secondary cardiomyopathies is not different from that of cardiomyopathies due to other causes either. Patients with neuromuscular disorders require early cardiologic investigations and close follow-ups, patients with cardiomyopathies require neurological investigation and avoidance of muscle toxic medication if a neuromuscular disorder is diagnosed. Which patients with cardiomyopathy profit most from primary stroke prevention is unsolved and requires further investigations. © 2013 Elsevier Inc.
Lacourpaille L.,University of Nantes |
Hug F.,University of Nantes |
Bouillard K.,University of Nantes |
Hogrel J.-Y.,Institute Of Myologie |
Nordez A.,University of Nantes
Physiological Measurement | Year: 2012
The aim of the present study was to assess the reliability of shear elastic modulus measurements performed using supersonic shear imaging (SSI) in nine resting muscles (i.e. gastrocnemius medialis, tibialis anterior, vastus lateralis, rectus femoris, triceps brachii, biceps brachii, brachioradialis, adductor pollicis obliquus and abductor digiti minimi) of different architectures and typologies. Thirty healthy subjects were randomly assigned to the intra-session reliability (n = 20), inter-day reliability (n = 21) and the inter-observer reliability (n = 16) experiments. Muscle shear elastic modulus ranged from 2.99 (gastrocnemius medialis) to 4.50 kPa (adductor digiti minimi and tibialis anterior). On the whole, very good reliability was observed, with a coefficient of variation (CV) ranging from 4.6% to 8%, except for the inter-operator reliability of adductor pollicis obliquus (CV = 11.5%). The intraclass correlation coefficients were good (0.871 ± 0.045 for the intra-session reliability, 0.815 ± 0.065 for the inter-day reliability and 0.709 ± 0.141 for the inter-observer reliability). Both the reliability and the ease of use of SSI make it a potentially interesting technique that would be of benefit to fundamental, applied and clinical research projects that need an accurate assessment of muscle mechanical properties. © 2012 Institute of Physics and Engineering in Medicine.
Hogrel J.-Y.,Institute Of Myologie
BMC Musculoskeletal Disorders | Year: 2015
Background: Grip strength is a variable which may be important to measure and follow in various populations. A new dynamometer with high accuracy and sensitivity has recently been developed to assess grip strength. The objectives of this work were to provide norms of maximal isometric grip strength measured with this new dynamometer (the MyoGrip device), to assess the reliability of measurements, to compare the measurements obtained with MyoGrip and Jamar dynamometers and finally to establish predictive equations from a population of healthy subjects (children and adults). Methods: Measurements of maximal isometric grip strength using the MyoGrip and the Jamar (which is considered as the gold-standard) were performed on 346 healthy subjects aged from 5 to 80 years. Test-retest reliability for both devices was assessed on 77 subjects. Predictive equations were computed on subjects younger than 60 years of age in order to avoid the effects of aging on strength. Results: This study provides norms for isometric grip strength for health subjects from 5 to 80 years. Reliability of the MyoGrip device was excellent (intraclass correlation coefficient: 0.967). Despite good correlation between devices, the Jamar tended to overestimate maximal grip strength by about 14 %. A single predictive equation for men and women, adults and children incorporating hand circumference only can be used to compute the predicted theoretical maximal grip strength. Conclusions: The MyoGrip device is a reliable tool for measuring isometric grip strength. Owing to its unique metrological features, it can be used in very weak patients or in any situation where high precision and accuracy are required. © 2015 Hogrel.
Berrih-Aknin S.,French Institute of Health and Medical Research |
Berrih-Aknin S.,French National Center for Scientific Research |
Berrih-Aknin S.,Paris-Sorbonne University |
Berrih-Aknin S.,Institute Of Myologie |
And 5 more authors.
Journal of Autoimmunity | Year: 2014
Myasthenia gravis is characterized by muscle weakness and abnormal fatigability. It is an autoimmune disease caused by the presence of antibodies against components of the muscle membrane localized at the neuromuscular junction. In most cases, the autoantibodies are against the acetylcholine receptor (AChR). Recently, other targets have been described such as the MuSK protein (muscle-specific kinase) or the LRP4 (lipoprotein related protein 4). Myasthenia gravis can be classified according to the profile of the autoantibodies, the location of the affected muscles (ocular versus generalized), the age of onset of symptoms and thymic abnormalities.The disease generally begins with ocular symptoms (ptosis and/or diplopia) and extends to other muscles in 80% of cases. Other features that characterize MG include the following: variability, effort induced worsening, successive periods of exacerbation during the course of the disease, severity dependent on respiratory and swallowing impairment (if rapid worsening occurs, a myasthenic crisis is suspected), and an association with thymoma in 20% of patients and with other autoimmune diseases such as hyperthyroidism and Hashimoto's disease. The diagnosis is based on the clinical features, the benefit of the cholinesterase inhibitors, the detection of specific autoantibodies (anti-AChR, anti-MuSK or anti-LRP4), and significant decrement evidenced by electrophysiological tests.In this review, we briefly describe the history and epidemiology of the disease and the diagnostic and clinical classification. The neonatal form of myasthenia is explained, and finally we discuss the main difficulties of diagnosis. © 2014 Elsevier Ltd.
Weiss J.M.,French Institute of Health and Medical Research |
Cufi P.,French Institute of Health and Medical Research |
Bismuth J.,French Institute of Health and Medical Research |
Eymard B.,Institute Of Myologie |
And 3 more authors.
Immunobiology | Year: 2013
Myasthenia gravis (MG), a neuromuscular disease mediated by autoantibodies against the anti-acetylcholine receptor, is often associated with thymic hyperplasia characterized by ectopic germinal centers that contain autoreactive T and B cells. The MG thymus is the site of active neoangiogenic processes including the abnormal development of high endothelial venules (HEVs). This study tested the hypothesis that thymic HEVs and associated chemokines participate in MG pathology by mediating peripheral cell recruitment to the MG thymus.We observed that the number of HEVs positively correlated with the degree of thymic hyperplasia. Testing various chemokines, we demonstrated that thymic HEVs selectively expressed SDF-1 mRNA and presented SDF-1 protein on the lumen side. Antigen presenting cells (APCs) such as monocytes/macrophages, dendritic cells (DCs) and B cells expressing SDF-1 receptor CXCR4 were detected inside and around thymic HEVs. In the periphery, CXCR4 expression was especially reduced on myeloid DCs (mDCs). In parallel, the number of mDCs was decreased suggesting a recruitment of these cells from the periphery to MG thymus. Corticosteroid treatment normalized the number of HEVs and may thus decrease the recruitment of peripheral cells. Indeed, it restored the level of CXCR4 on peripheral mDCs and the number of peripheral mDCs.Altogether, our results suggest that HEV development and engagement of SDF-1 contribute to MG pathology by recruitment of peripheral B cells and APCs to the MG thymus. © 2012 Elsevier GmbH.
Eymard B.,Institute Of Myologie
Revue de Medecine Interne | Year: 2014
Myasthenia gravis is an autoimmune disease due to specific antibodies inducing a neuromuscular transmission defect causing muscle fatigability. If onset of the disease may be at any age, myasthenia gravis concerns mostly young adults, in majority females. The disease characteristic features are the following: ocular symptoms (ptosis or diplopia) as main initial manifestation, extension to other muscles in 80% of the cases, variability of the deficit, effort induced worsening, successive periods of exacerbation during the disease course, severity depending on respiratory and swallowing impairment (if rapid worsening, a myasthenic crisis is to be suspected), association with thymoma in 20% of patients and with other various autoimmune diseases, most commonly hyperthyroidism and Hashimoto's disease. Diagnosis relies on the clinical features, improvement with cholinesterase inhibitors, detection of specific autoantibodies (anti-AChR or anti-MuSK), and significant decrement evidenced by electrophysiological tests. The points concerning specifically the internist have been highlighted in this article: diagnostic traps, associated autoimmune diseases, including inflammatory myopathies that may mimic myasthenia gravis, adverse effects of medications commonly used in internal medicine, some of them inducing myasthenic syndromes. The treatment is well codified: the treatment is well codified: (1) respect of adverse drugs contra-indications, systematically use of cholinesterase inhibitors, (2) thymectomy if thymoma completed with radiotherapy if malignant, (3) corticosteroids or immunosuppressive agent in severe or disabling form, (4) intensive care unit monitoring, plasmapheresis or intravenous immunoglobulins for patients with myasthenic crisis. © 2013.
Institute Of Myologie | Date: 2013-03-29
The invention relates to a system for measuring a palmar gripping force, comprising a device (1) for measuring said palmar gripping force, which device comprises: a handle configured to receive a palmar gripping force; a force sensor (3); and an electronic module (6) integrated into the device and comprising at least one microcontroller (61) connected to the sensor (3) and able to process data originating from said sensor (3), characterised in that the force sensor comprises a stress gauge with a minimum precision of 50 g; a controlling system is also provided and comprises means able to do the following: calibrate the sensor using a linear calibration curve; and transmit the sensor measurements to a display unit (8) and/or a storage unit and/or a processing unit, preferably via wired or wireless means.
Institute Of Myologie | Date: 2013-09-13
The invention relates to a device for measuring the pinch force between a persons thumb and index finger, comprising: first and second parallel blades, said blades being disposed at a distance from one another and embedded at a first longitudinal end thereof; a sensor for measuring the pinch force exerted between the two blades at the second longitudinal end thereof, perpendicularly to the respective main planes thereof; a means for displaying the pinch force; and a means for storing and/or processing the pinch force. According to the invention, the first blade forms part of a rigid parallelepiped frame and the second blade is disposed in the space inside the parallelogram.