muscle disorders
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2022 ◽  
Vol 12 ◽  
Author(s):  
Slobodan Sekulić ◽  
Branislava Jakovljević ◽  
Darinka Korovljev ◽  
Svetlana Simić ◽  
Ivan Čapo ◽  
...  

Polyhydramnios is a condition related to an excessive accumulation of amniotic fluid in the third trimester of pregnancy and it can be acute and chronic depending on the duration. Published data suggest that during muscle development, in the stage of late histochemical differentiation decreased mechanical loading cause decreased expression of myosin heavy chain (MHC) type 1 leading to slow-to-fast transition. In the case of chronic polyhydramnios, histochemical muscle differentiation could be affected as a consequence of permanent decreased physical loading. Most affected would be muscles which are the most active i.e., spine extensor muscles and muscles of legs. Long-lasting decreased mechanical loading on muscle should cause decreased expression of MHC type 1 leading to slow-to-fast transition, decreased number of muscle fiber type I especially in extensor muscles of spine and legs. Additionally, because MHC type 1 is present in all skeletal muscles it could lead to various degrees of hypotrophy depending on constituting a percentage of MHC type 1 in affected muscles. These changes in the case of preexisting muscle disorders have the potential to deteriorate the muscle condition additionally. Given these facts, idiopathic chronic polyhydramnios is a rare opportunity to study the influence of reduced physical loading on muscle development in the human fetus. Also, it could be a medical entity to examine the influence of micro- and hypogravity conditions on the development of the fetal muscular system during the last trimester of gestation.


2022 ◽  
Author(s):  
Natália dos Reis Ferreira ◽  
Carlos Miguel Marto ◽  
Aleli Tôrres Oliveira ◽  
Maria João Rodrigues ◽  
Marcos Fabio DosSantos

Abstract Background Temporomandibular Disorder (TMD) is a generic term applied to describe musculoskeletal disorders that affect the temporomandibular joint (TMJ), the masticatory muscles and the related structures. TMD comprises two groups of disorders, namely intra-articular TMD and masticatory muscle disorders. There is still difficulty in establishing the effectiveness of different therapeutic modalities for TMD with robust evidence, despite the large volume of publications in the area. The lack of outcomes standardization may represent a limiting factor in the search for scientific evidence. Objective This study aims to develop a core outcome sets (COS) for clinical trials in intra-articular TMD and masticatory muscle disorders. Methods The protocol for determining the COS-TMD will consist of three phases: 1. Synthesis of TMD Management Intervention Outcomes. The identification of outcomes will be carried out through a systematic review, which will include randomized clinical trials that evaluated the effectiveness of interventions used in TMD management. 2. Through a two-round international Delphi survey, the list of outcomes will be scored by three panels of stakeholders. 3. A representative sample of key stakeholders will be invited to participate in a face-to-face meeting where they can discuss the results of the Delphi survey and determine the final core set. Conclusions The implementation of this protocol will determine the COS-TMD, which will be made available for use in all TMD clinical studies. The use of COS when planning and reporting TMD clinical trials will reduce the risk of publication bias and enable proper comparison of results found by different studies.


2022 ◽  
pp. 143-161
Author(s):  
Bruce Carlson
Keyword(s):  

2021 ◽  
Vol 2 (2) ◽  
pp. 52-59
Author(s):  
Venny Diana

Musculoskeletal disorders are disorders that occur in one of the skeletal organs or muscles of the body such as congenital abnormalities in the upper and lower extremities, nerve and muscle disorders, inflammatory infections of bones and joints, musculoskeletal metabolic disorders, degenerative musculoskeletal disorders (spine, upper extremities) and below). The study aimed To analyze the static condition of the workers' complaints of musculoskeletal disorders (MSDs). Using literature review with scoping review method. The data was collected through internet searches using Google Scholar and PubMed with the keywords static conditions, complaints of MSDs, ergonomic position, musculoskeletal disorders, the influence of static conditions, with a range of research years is 2015-2020. Results found 83 articles matching the keyword. A review of 9 research articles that met the inclusion criteria found 4 aspects, namely the factor of length of work more than 1 year, age, working hours and using the same extremity for a long period of time will increase the risk of MSDs, Doing work in awkward positions for 5- 8 hours/day increases the risk of MSDs in workers, especially nurses, The emergence of MSDs symptoms is higher in women, namely in the lower back and neck area, The pain felt due to MSDs disorders can be severe, namely in the lower back, shoulders, neck, wrists , knees and ankles. There is a relationship with static positions/non-ergonomic conditions at work, these non-ergonomic conditions do not directly cause complaints but in the long term complaints will arise. The female gender is at high risk of experiencing MSDs, the length of work and length of time working will affect the emergence of MSDs, there are 12 static conditions found in someone when doing work, the main complaint that appears in MSDs is pain.


Metabolites ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 855
Author(s):  
Federica Rossin ◽  
Elena Avitabile ◽  
Giorgia Catarinella ◽  
Ersilia Fornetti ◽  
Stefano Testa ◽  
...  

Skeletal muscle is a very dynamic and plastic tissue, being essential for posture, locomotion and respiratory movement. Muscle atrophy or genetic muscle disorders, such as muscular dystrophies, are characterized by myofiber degeneration and replacement with fibrotic tissue. Recent studies suggest that changes in muscle metabolism such as mitochondrial dysfunction and dysregulation of intracellular Ca2+ homeostasis are implicated in many adverse conditions affecting skeletal muscle. Accumulating evidence also suggests that ER stress may play an important part in the pathogenesis of inflammatory myopathies and genetic muscle disorders. Among the different known proteins regulating ER structure and function, we focused on RTN-1C, a member of the reticulon proteins family localized on the ER membrane. We previously demonstrated that RTN-1C expression modulates cytosolic calcium concentration and ER stress pathway. Moreover, we recently reported a role for the reticulon protein in autophagy regulation. In this study, we found that muscle differentiation process positively correlates with RTN-1C expression and UPR pathway up-regulation during myogenesis. To better characterize the role of the reticulon protein alongside myogenic and muscle regenerative processes, we performed in vivo experiments using either a model of muscle injury or a photogenic model for Duchenne muscular dystrophy. The obtained results revealed RTN-1C up-regulation in mice undergoing active regeneration and localization in the injured myofibers. The presented results strongly suggested that RTN-1C, as a protein involved in key aspects of muscle metabolism, may represent a new target to promote muscle regeneration and repair upon injury.


Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3428
Author(s):  
Julien Ochala ◽  
Carrie J. Finno ◽  
Stephanie J. Valberg

Myosinopathies are defined as a group of muscle disorders characterized by mutations in genes encoding myosin heavy chains. Their exact molecular and cellular mechanisms remain unclear. In the present study, we have focused our attention on a MYH1-related E321G amino acid substitution within the head region of the type IIx skeletal myosin heavy chain, associated with clinical signs of atrophy, inflammation and/or profound rhabdomyolysis, known as equine myosin heavy chain myopathy. We performed Mant-ATP chase experiments together with force measurements on isolated IIx myofibres from control horses (MYH1E321G−/−) and Quarter Horses homozygous (MYH1E321G+/+) or heterozygous (MYH1E321G+/−) for the E321G mutation. The single residue replacement did not affect the relaxed conformations of myosin molecules. Nevertheless, it significantly increased its active behaviour as proven by the higher maximal force production and Ca2+ sensitivity for MYH1E321G+/+ in comparison with MYH1E321G+/− and MYH1E321G−/− horses. Altogether, these findings indicate that, in the presence of the E321G mutation, a molecular and cellular hyper-contractile phenotype occurs which could contribute to the development of the myosin heavy chain myopathy.


2021 ◽  
Vol 61 ◽  
pp. 102600
Author(s):  
Gisela Sjøgaard ◽  
Stephanie Mann ◽  
Jesper Stejnicher Drongstrup Jensen ◽  
Anne Skov Oestergaard ◽  
Tina Dalager

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eriya Kenjo ◽  
Hiroyuki Hozumi ◽  
Yukimasa Makita ◽  
Kumiko A. Iwabuchi ◽  
Naoko Fujimoto ◽  
...  

AbstractGenome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal muscle tissues. In general, AAV vectors are used for in vivo delivery, but AAV injections cannot be repeated because of neutralization antibodies. Here we report a chemically defined lipid nanoparticle (LNP) system which is able to deliver Cas9 mRNA and sgRNA into skeletal muscle by repeated intramuscular injections. Although the expressions of Cas9 protein and sgRNA were transient, our LNP system could induce stable genomic exon skipping and restore dystrophin protein in a DMD mouse model that harbors a humanized exon sequence. Furthermore, administration of our LNP via limb perfusion method enables to target multiple muscle groups. The repeated administration and low immunogenicity of our LNP system are promising features for a delivery vehicle of CRISPR-Cas9 to treat skeletal muscle disorders.


2021 ◽  
Vol 154 (9) ◽  
Author(s):  
Vincenzo Sorrentino

Mutations in the RYR1 gene are the most common cause of nondystrophic congenital myopathies. Mutations in RYR1 were initially identified in individuals susceptible to malignant hyperthermia, a pharmacogenetic disorder triggered by volatile anesthetics and succinylcholine. Shortly after, mutations in RYR1 were identified in patients with central core disease, which is the most frequent congenital myopathy, and in other muscle disorders, collectively referred to as RYR1-related myopathies. RYR1 mutations are also responsible of some acute pathological conditions triggered by heat- and exercise-induced stress, named exertional heat stroke and exertional-induced rhabdomyolysis, which, similarly to malignant hyperthermia, occur in otherwise healthy individuals with normal skeletal muscle functions. Hundreds of causative mutations linked to RYR1-related diseases have been identified. These mutations are clustered in three regions that are referred to as the N-terminal, central, and C-terminal hot spots. Recent developments in cryo-EM techniques have provided high-resolution reconstructions of the channel, allowing a much better definition of the structural domains within the large N-terminal cytoplasmic region and in the C-terminal domain containing six transmembrane helices and the pore region of the channel. RYR1 mutations may either activate or inhibit channel function or, in some cases, can reduce the expression levels of RYR1 protein. However, similar clinical phenotypes can result from mutations with opposing effects on RYR1 function, or little or no correlation can be found between the observed clinical phenotype and localization of mutations in the structural domains of the RYR1 channel, even though recent studies indicate that clinically severe cases are mostly recessive or due to mutations located in the bridging solenoid. Recent results on the identification of RYR1 mutations in patients with myopathies will be presented.


2021 ◽  
Author(s):  
Alexis Ruiz ◽  
Sofia Benucci ◽  
Urs Duthaler ◽  
Christoph P Bachmann ◽  
Martina Franchini ◽  
...  

To date there are no therapies for patients with congenital myopathies, muscle disorders causing poor quality of life of affected individuals. In approximately 30% of the cases, patients with congenital myopathies carry either dominant or recessive mutations in the RYR1 gene; recessive RYR1 mutations are accompanied by reduction of RyR1 expression and content in skeletal muscles and are associated with fiber hypotrophy and muscle weakness. Importantly, muscles of patients with recessive RYR1 mutations exhibit increased content of class II histone de-acetylases and of DNA genomic methylation. We recently created a mouse model knocked-in for the p.Q1970fsX16+p.A4329D RyR1 mutations, which are isogenic to those carried by a severely affected child suffering from a recessive form of RyR1-related multi-mini core disease. The phenotype of the RyR1 mutant mice recapitulates many aspects of the clinical picture of patients carrying recessive RYR1 mutations. We treated the compound heterozygous mice with a combination of two drugs targeting DNA methylases and class II histone de-acetylases. Here we show that treatment of the mutant mice with drugs targeting epigenetic enzymes improves muscle strength, RyR1 protein content and muscle ultrastructure. This study provides proof of concept for the pharmacological treatment of patients with congenital myopathies linked to recessive RYR1 mutations.


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