Emerging new tools to study and treat muscle pathologies: genetics and molecular mechanisms underlying skeletal muscle development, regeneration, and disease.

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Crist, Colin

2017-01-01

Skeletal muscle is the most abundant tissue in our body, is responsible for generating the force required for movement, and is also an important thermogenic organ. Skeletal muscle is an enigmatic tissue because while on the one hand, skeletal muscle regeneration after injury is arguably one of the best-studied stem cell-dependent regenerative processes, on the other hand, skeletal muscle is still subject to many degenerative disorders with few therapeutic options in the clinic. It is important to develop new regenerative medicine-based therapies for skeletal muscle. Future therapeutic strategies should take advantage of rapidly developing technologies enabling the differentiation of skeletal muscle from human pluripotent stem cells, along with precise genome editing, which will go hand in hand with a steady and focused approach to understanding underlying mechanisms of skeletal muscle development, regeneration, and disease. In this review, I focus on highlighting the recent advances that particularly have relied on developmental and molecular biology approaches to understanding muscle development and stem cell function. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Development of Human Muscle Protein Measurement with MRI

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Lin, Chen; Evans, Harlan; Leblanc, Adrian D.

1997-01-01

It is known that micro-gravity has a strong influence on the human musculoskeletal system. A number of studies have shown that significant changes in skeletal muscles occur in both space flight and bedrest simulation. In our 5 week bedrest study, the cross-sectional area of soleus-gastrocnemius decreased about 12% while the cross-sectional area of anterior calf muscles decreased about 4%. Using volume measurements, these losses increased after 17 weeks to approximately 30% and 21% respectively. Significant muscle atrophy was also found on the SL-J crew members after only 8 days in space. It is important that these effects are fully understood so that countermeasures can be developed. The same knowledge might also be useful in preventing muscle atrophy related to other medical problems. A major problem with anatomical measurements of muscle during bed rest and microgravity is the influence of fluid shifts and water balance on the measurement of muscle volume, especially when the exposure duration is short and the atrophy is relatively small. Fluid shifts were documented in Skylab by visual observations of blood vessel distention, rapid changes in limb volume, center of mass measurements and subjective descriptions such as puffy faces and head fullness. It has been reported that the muscle water content of biopsied soleus muscles decreased following 8 hours of head down tilt bed rest. Three aspects of fluid shifts that can affect volume measurements are: first, the shift of fluid that occurs whenever there is a change from upright to a recumbent position and vice versa; second, the potential for fluid accumulation in the lower limbs resulting from muscle damage caused by overextending atrophied muscle or swelling caused by deconditioned precapillary sphincter muscles during reambulation; third, the net change of hydration level during and after bed rest or spaceflight. Because of these transitory fluid shifts, muscle protein is expected to represent muscle capacity

Development of the Muscle Dysmorphia Inventory (MDI).

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Rhea, D J; Lantz, C D; Cornelius, A E

2004-12-01

The development of the 6-factor, 27-item Muscle Dysmorphia Inventory (MDI) was based on Lantz et al. proposed model of characteristics associated with Muscle Dysmorphia. quantitative procedures including item-to-total correlations, exploratory and confirmatory factor analyses, and structure equation modeling confirmed the construct validity of the scale. Convergent validity was also tested. bodybuilding and powerlifting competition venues, weight training facilities, and university athletic venues. the 1(st) study consisted of 77 experienced male free weight lifters. The 2(nd) study consisted of 156 male non-competitive bodybuilders and weight lifters and 168 elite level powerlifters and bodybuilders. The 3(rd) study consisted of 151 male and female bodybuilders and weight lifters. each participant completed demographic information, the MDI, Drive for Thinness subscale of the Eating Disorder Inventory, and the Training Dependency subscale of the Bodybuilding Dependence Scale. Reliability estimates (Cronbach's a) ranged from 0.72 to 0.94. Factor loadings in all 3 studies supported the 6-factor structure (size/symmetry, supplement use, exercise dependence, pharmacological use, dietary behavior, and physique protection). Much of the scale validation was focused on construct validity, however, correlations with the MDI's subscales and the Training Dependency subscale of the Bodybuilding Dependence Scale and the Drive for Thinness subscale of the Eating Disorder Inventory provided evidence of convergent validity also. From these preliminary results, the MDI appears to contribute to the identification of a newly formed disorder by offering a multi-dimensional measure of factors related to Muscle Dysmorphia.

Muscle development in healthy children evaluated by bioelectrical impedance analysis.

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Uchiyama, Tomoka; Nakayama, Takahiro; Kuru, Satoshi

2017-02-01

This study aimed to use bioelectrical impedance analysis (BIA) to generate a new muscle density index (MDI), the MDI_BIA, to evaluate muscle development, and to demonstrate the changes that occur in the BIA-based muscle cross-sectional area index (MCAI_BIA) that accompany growth. We also sought to determine the traceability of chronological changes in the MDI_BIA and MCAI_BIA. Healthy children (n=112) aged 8.68±3.16years (0.33-14.00years) underwent bioelectrical impedance (BI) measurements of their upper arms, thighs, and lower legs. The MDI_BIA and MCAI_BIA were calculated, and cross-sectional investigations were conducted into the changes in these indices that accompanied growth. Data collected after 1.10±0.08years from 45 participants determined the traceability of the chronological changes in the MDI_BIA and MCAI_BIA. The MDI_BIA and MCAI_BIA were significantly positively correlated with age and height at all locations (Pchildren, and they showed significant chronological increases. Hence, these indices could be used to represent muscle development and muscle mass increases. BIA is non-invasive, convenient, and economical and it may be useful in evaluating muscle development and muscle cross-sectional areas in children. Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

DNA methylation dynamics in muscle development and disease

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Elvira eCarrio

2015-03-01

Full Text Available DNA methylation is an essential epigenetic modification for mammalian development and is crucial for the establishment and maintenance of cellular identity. Traditionally, DNA methylation has been considered as a permanent repressive epigenetic mark. However, the application of genome-wide approaches has allowed the analysis of DNA methylation in different genomic contexts revealing a more dynamic regulation than originally thought, since active DNA methylation and demethylation occur during cellular differentiation and tissue specification. Satellite cells are the primary stem cells in adult skeletal muscle and are responsible for postnatal muscle growth, hypertrophy, and muscle regeneration. This review outlines the published data regarding DNA methylation changes along the skeletal muscle program, in both physiological and pathological conditions, to better understand the epigenetic mechanisms that control myogenesis

Insights into skeletal muscle development and applications in regenerative medicine.

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Tran, T; Andersen, R; Sherman, S P; Pyle, A D

2013-01-01

Embryonic and postnatal development of skeletal muscle entails highly regulated processes whose complexity continues to be deconstructed. One key stage of development is the satellite cell, whose niche is composed of multiple cell types that eventually contribute to terminally differentiated myotubes. Understanding these developmental processes will ultimately facilitate treatments of myopathies such as Duchenne muscular dystrophy (DMD), a disease characterized by compromised cell membrane structure, resulting in severe muscle wasting. One theoretical approach is to use pluripotent stem cells in a therapeutic setting to help replace degenerated muscle tissue. This chapter discusses key myogenic developmental stages and their regulatory pathways; artificial myogenic induction in pluripotent stem cells; advantages and disadvantages of DMD animal models; and therapeutic approaches targeting DMD. Furthermore, skeletal muscle serves as an excellent paradigm for understanding general cell fate decisions throughout development. Copyright © 2013 Elsevier Inc. All rights reserved.

New perspectives on the development of muscle contractures following central motor lesions.

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Pingel, J; Bartels, E M; Nielsen, J B

2017-02-15

Muscle contractures are common in patients with central motor lesions, but the mechanisms responsible for the development of contractures are still unclear. Increased or decreased neural activation, protracted placement of a joint with the muscle in a short position and muscle atrophy have been suggested to be involved, but none of these mechanisms are sufficient to explain the development of muscle contractures alone. Here we propose that changes in tissue homeostasis in the neuromuscular-tendon-connective tissue complex is at the heart of the development of contractures, and that an integrated physiological understanding of the interaction between neural, mechanical and metabolic factors, as well as genetic and epigenetic factors, is necessary in order to unravel the mechanisms that result in muscle contractures. We hope thereby to contribute to a reconsideration of how and why muscle contractures develop in a way which will open a window towards new insight in this area in the future. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

New perspectives on the development of muscle contractures following central motor lesions

DEFF Research Database (Denmark)

Pingel, Jessica; Bartels, Else Marie; Nielsen, Jens Bo

2017-01-01

Muscle contractures are common in patients with central motor lesions, but the mechanisms responsible for the development of contractures are still unclear. Increased or decreased neural activation, protracted placement of a joint with the muscle in a short position and muscle atrophy have been...... suggested to be involved, but none of these mechanisms are sufficient to explain the development of muscle contractures alone. Here we propose that changes in tissue homeostasis in the neuro-muscular-tendon-connective tissue complex is at the heart of the development of contractures, and that an integrated...... physiological understanding of the interaction between neural, mechanical and metabolic factors, as well as genetic and epigenetic factors, is necessary in order to unravel the mechanisms that result in muscle contractures. We hope thereby to contribute to a reconsideration of how and why muscle contractures...

Development of the Muscle Appearance Satisfaction Scale: a self-report measure for the assessment of muscle dysmorphia symptoms.

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Mayville, Stephen B; Williamson, Donald A; White, Marney A; Netemeyer, Richard G; Drab, Danae L

2002-12-01

Muscle dysmorphia has recently been described as a variant of body dysmorphic disorder that involves an intense preoccupation with one's perceived lack of muscle size. Currently, no assessment measures specific to the cognitive, affective, and behavioral dimensions of the construct of muscle dysmorphia have been published. To address this need, the authors developed the Muscle Appearance Satisfaction Scale (MASS), a brief 19-item self-report measure for the assessment of muscle dysmorphia symptoms. Psychometric evaluation of the MASS across two samples of male weight lifting participants (total N = 372) revealed a stable five-factor structure. An evaluation of factor content resulted in the following factor labels: Bodybuilding Dependence, Muscle Checking, Substance Use, Injury, and Muscle Satisfaction. Internal consistency, test-retest reliability, and construct validity were established with the MASS total score and its subscales. The authors believe the MASS will be a useful measure for research and applied work relating to muscle dysmorphia.

Neurohypophyseal hormones: novel actors of striated muscle development and homeostasis

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Alessandra Costa

2014-09-01

Full Text Available Since the 1980's, novel functional roles of the neurohypophyseal hormones vasopressin and oxytocin have emerged. Several studies have investigated the effects of these two neurohormones on striated muscle tissues, both in vitro and in vivo. The effects of vasopressin on skeletal myogenic cells, developing muscle and muscle homeostasis have been documented. Oxytocin appears to have a greater influence on cardiomyocite differentiation and heart homeostasis. This review summarizes the studies on these novel roles of the two neurohypophyseal hormones, and open the possibility of new therapeutic approaches for diseases affecting striated muscle.

Muscle type-specific responses to NAD+ salvage biosynthesis promote muscle function in Caenorhabditis elegans.

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Vrablik, Tracy L; Wang, Wenqing; Upadhyay, Awani; Hanna-Rose, Wendy

2011-01-15

Salvage biosynthesis of nicotinamide adenine dinucleotide (NAD(+)) from nicotinamide (NAM) lowers NAM levels and replenishes the critical molecule NAD(+) after it is hydrolyzed. This pathway is emerging as a regulator of multiple biological processes. Here we probe the contribution of the NAM-NAD(+) salvage pathway to muscle development and function using Caenorhabditis elegans. C. elegans males with mutations in the nicotinamidase pnc-1, which catalyzes the first step of this NAD(+) salvage pathway, cannot mate due to a spicule muscle defect. Multiple muscle types are impaired in the hermaphrodites, including body wall muscles, pharyngeal muscles and vulval muscles. An active NAD(+) salvage pathway is required for optimal function of each muscle cell type. However, we found surprising muscle-cell-type specificity in terms of both the timing and relative sensitivity to perturbation of NAD(+) production or NAM levels. Active NAD(+) biosynthesis during development is critical for function of the male spicule protractor muscles during adulthood, but these muscles can surprisingly do without salvage biosynthesis in adulthood under the conditions examined. The body wall muscles require ongoing NAD(+) salvage biosynthesis both during development and adulthood for maximum function. The vulval muscles do not function in the presence of elevated NAM concentrations, but NAM supplementation is only slightly deleterious to body wall muscles during development or upon acute application in adults. Thus, the pathway plays distinct roles in different tissues. As NAM-NAD(+) biosynthesis also impacts muscle differentiation in vertebrates, we propose that similar complexities may be found among vertebrate muscle cell types. Copyright © 2010 Elsevier Inc. All rights reserved.

Transcriptional profiling identifies differentially expressed genes in developing turkey skeletal muscle

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Velleman Sandra G

2011-03-01

Full Text Available Abstract Background Skeletal muscle growth and development from embryo to adult consists of a series of carefully regulated changes in gene expression. Understanding these developmental changes in agriculturally important species is essential to the production of high quality meat products. For example, consumer demand for lean, inexpensive meat products has driven the turkey industry to unprecedented production through intensive genetic selection. However, achievements of increased body weight and muscle mass have been countered by an increased incidence of myopathies and meat quality defects. In a previous study, we developed and validated a turkey skeletal muscle-specific microarray as a tool for functional genomics studies. The goals of the current study were to utilize this microarray to elucidate functional pathways of genes responsible for key events in turkey skeletal muscle development and to compare differences in gene expression between two genetic lines of turkeys. To achieve these goals, skeletal muscle samples were collected at three critical stages in muscle development: 18d embryo (hyperplasia, 1d post-hatch (shift from myoblast-mediated growth to satellite cell-modulated growth by hypertrophy, and 16wk (market age from two genetic lines: a randombred control line (RBC2 maintained without selection pressure, and a line (F selected from the RBC2 line for increased 16wk body weight. Array hybridizations were performed in two experiments: Experiment 1 directly compared the developmental stages within genetic line, while Experiment 2 directly compared the two lines within each developmental stage. Results A total of 3474 genes were differentially expressed (false discovery rate; FDR Conclusions The current study identified gene pathways and uncovered novel genes important in turkey muscle growth and development. Future experiments will focus further on several of these candidate genes and the expression and mechanism of action of

Structure–function relationship of skeletal muscle provides inspiration for design of new artificial muscle

International Nuclear Information System (INIS)

Gao, Yingxin; Zhang, Chi

2015-01-01

A variety of actuator technologies have been developed to mimic biological skeletal muscle that generates force in a controlled manner. Force generation process of skeletal muscle involves complicated biophysical and biochemical mechanisms; therefore, it is impossible to replace biological muscle. In biological skeletal muscle tissue, the force generation of a muscle depends not only on the force generation capacity of the muscle fiber, but also on many other important factors, including muscle fiber type, motor unit recruitment, architecture, structure and morphology of skeletal muscle, all of which have significant impact on the force generation of the whole muscle or force transmission from muscle fibers to the tendon. Such factors have often been overlooked, but can be incorporated in artificial muscle design, especially with the discovery of new smart materials and the development of innovative fabrication and manufacturing technologies. A better understanding of the physiology and structure–function relationship of skeletal muscle will therefore benefit the artificial muscle design. In this paper, factors that affect muscle force generation are reviewed. Mathematical models used to model the structure–function relationship of skeletal muscle are reviewed and discussed. We hope the review will provide inspiration for the design of a new generation of artificial muscle by incorporating the structure–function relationship of skeletal muscle into the design of artificial muscle. (topical review)

Structure-function relationship of skeletal muscle provides inspiration for design of new artificial muscle

Science.gov (United States)

Gao, Yingxin; Zhang, Chi

2015-03-01

A variety of actuator technologies have been developed to mimic biological skeletal muscle that generates force in a controlled manner. Force generation process of skeletal muscle involves complicated biophysical and biochemical mechanisms; therefore, it is impossible to replace biological muscle. In biological skeletal muscle tissue, the force generation of a muscle depends not only on the force generation capacity of the muscle fiber, but also on many other important factors, including muscle fiber type, motor unit recruitment, architecture, structure and morphology of skeletal muscle, all of which have significant impact on the force generation of the whole muscle or force transmission from muscle fibers to the tendon. Such factors have often been overlooked, but can be incorporated in artificial muscle design, especially with the discovery of new smart materials and the development of innovative fabrication and manufacturing technologies. A better understanding of the physiology and structure-function relationship of skeletal muscle will therefore benefit the artificial muscle design. In this paper, factors that affect muscle force generation are reviewed. Mathematical models used to model the structure-function relationship of skeletal muscle are reviewed and discussed. We hope the review will provide inspiration for the design of a new generation of artificial muscle by incorporating the structure-function relationship of skeletal muscle into the design of artificial muscle.

Nuclear Positioning in Muscle Development and Disease

OpenAIRE

Eric eFolker; Mary eBaylies

2013-01-01

Muscle disease as a group is characterized by muscle weakness, muscle loss, and impaired muscle function. Although the phenotype is the same, the underlying cellular pathologies, and the molecular causes of these pathologies, are diverse. One common feature of many muscle disorders is the mispositioning of myonuclei. In unaffected individuals myonuclei are spaced throughout the periphery of the muscle fiber such that the distance between nuclei is maximized. However, in diseased muscles, th...

Relative Skeletal Muscle Mass Is Associated with Development of Metabolic Syndrome

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Byung Sam Park

2013-12-01

Full Text Available BackgroundVisceral adiposity is related to insulin resistance. Skeletal muscle plays a central role in insulin-mediated glucose disposal; however, little is known about the association between muscle mass and metabolic syndrome (MS. This study is to clarify the clinical role of skeletal muscle mass in development of MS.MethodsA total of 1,042 subjects were enrolled. Subjects with prior MS and chronic diseases were excluded. After 24 months, development of MS was assessed using NCEP-ATP III criteria. Skeletal muscle mass (SMM; kg, body fat mass (BFM; kg, and visceral fat area (VFA; cm2 were obtained from bioelectrical analysis. Then, the following values were calculated as follows: percent of SMM (SMM%; %: SMM (kg/weight (kg, skeletal muscle index (SMI; kg/m2: SMM (kg/height (m2, skeletal muscle to body fat ratio (MFR: SMM (kg/BFM (kg, and skeletal muscle to visceral fat ratio (SVR; kg/cm2: SMM (kg/VFA (cm2.ResultsAmong 838 subjects, 88 (10.5% were newly diagnosed with MS. Development of MS increased according to increasing quintiles of BMI, SMM, VFA, and SMI, but was negatively associated with SMM%, MFR, and SVR. VFA was positively associated with high waist circumference (WC, high blood pressure (BP, dysglycemia, and high triglyceride (TG. In contrast, MFR was negatively associated with high WC, high BP, dysglycemia, and high TG. SVR was negatively associated with all components of MS.ConclusionRelative SMM ratio to body composition, rather than absolute mass, may play a critical role in development of MS and could be used as a strong predictor.

Cancer cachexia-induced muscle atrophy: evidence for alterations in microRNAs important for muscle size.

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Lee, David E; Brown, Jacob L; Rosa-Caldwell, Megan E; Blackwell, Thomas A; Perry, Richard A; Brown, Lemuel A; Khatri, Bhuwan; Seo, Dongwon; Bottje, Walter G; Washington, Tyrone A; Wiggs, Michael P; Kong, Byung-Whi; Greene, Nicholas P

2017-05-01

Muscle atrophy is a hallmark of cancer cachexia resulting in impaired function and quality of life and cachexia is the immediate cause of death for 20-40% of cancer patients. Multiple microRNAs (miRNAs) have been identified as being involved in muscle development and atrophy; however, less is known specifically on miRNAs in cancer cachexia. The purpose of this investigation was to examine the miRNA profile of skeletal muscle atrophy induced by cancer cachexia to uncover potential miRNAs involved with this catabolic condition. Phosphate-buffered saline (PBS) or Lewis lung carcinoma cells (LLC) were injected into C57BL/6J mice at 8 wk of age. LLC animals were allowed to develop tumors for 4 wk to induce cachexia. Tibialis anterior muscles were extracted and processed to isolate small RNAs, which were used for miRNA sequencing. Sequencing results were assembled with mature miRNAs, and functions of miRNAs were analyzed by Ingenuity Pathway Analysis. LLC animals developed tumors that contributed to significantly smaller tibialis anterior muscles (18.5%) and muscle cross-sectional area (40%) compared with PBS. We found 371 miRNAs to be present in the muscle above background levels. Of these, nine miRNAs were found to be differentially expressed. Significantly altered groups of miRNAs were categorized into primary functionalities including cancer, cell-to-cell signaling, and cellular development among others. Gene network analysis predicted specific alterations of factors contributing to muscle size including Akt, FOXO3, and others. These results create a foundation for future research into the sufficiency of targeting these genes to attenuate muscle loss in cancer cachexia. Copyright © 2017 the American Physiological Society.

Non-myogenic Contribution to Muscle Development and Homeostasis: The Role of Connective Tissues.

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Nassari, Sonya; Duprez, Delphine; Fournier-Thibault, Claire

2017-01-01

Skeletal muscles belong to the musculoskeletal system, which is composed of bone, tendon, ligament and irregular connective tissue, and closely associated with motor nerves and blood vessels. The intrinsic molecular signals regulating myogenesis have been extensively investigated. However, muscle development, homeostasis and regeneration require interactions with surrounding tissues and the cellular and molecular aspects of this dialogue have not been completely elucidated. During development and adult life, myogenic cells are closely associated with the different types of connective tissue. Connective tissues are defined as specialized (bone and cartilage), dense regular (tendon and ligament) and dense irregular connective tissue. The role of connective tissue in muscle morphogenesis has been investigated, thanks to the identification of transcription factors that characterize the different types of connective tissues. Here, we review the development of the various connective tissues in the context of the musculoskeletal system and highlight their important role in delivering information necessary for correct muscle morphogenesis, from the early step of myoblast differentiation to the late stage of muscle maturation. Interactions between muscle and connective tissue are also critical in the adult during muscle regeneration, as impairment of the regenerative potential after injury or in neuromuscular diseases results in the progressive replacement of the muscle mass by fibrotic tissue. We conclude that bi-directional communication between muscle and connective tissue is critical for a correct assembly of the musculoskeletal system during development as well as to maintain its homeostasis in the adult.

Smyd3 is required for the development of cardiac and skeletal muscle in zebrafish.

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Tomoaki Fujii

Full Text Available Modifications of histone tails are involved in the regulation of a wide range of biological processes including cell cycle, cell survival, cell division, and cell differentiation. Among the modifications, histone methylation plays a critical role in cardiac and skeletal muscle differentiation. In our earlier studies, we found that SMYD3 has methyltransferase activity to histone H3 lysine 4, and that its up-regulation is involved in the tumorigenesis of human colon, liver, and breast. To clarify the role of Smyd3 in development, we have studied its expression patterns in zebrafish embryos and the effect of its suppression on development using Smyd3-specific antisense morpholino-oligonucleotides. We here show that transcripts of smyd3 were expressed in zebrafish embryos at all developmental stages examined and that knockdown of smyd3 in embryos resulted in pericardial edema and defects in the trunk structure. In addition, these phenotypes were associated with abnormal expression of three heart-chamber markers including cmlc2, amhc and vmhc, and abnormal expression of myogenic regulatory factors including myod and myog. These data suggest that Smyd3 plays an important role in the development of heart and skeletal muscle.

Muscle Deoxygenation Causes Muscle Fatigue

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Murthy, G.; Hargens, A. R.; Lehman, S.; Rempel, D.

1999-01-01

Muscle fatigue is a common musculoskeletal disorder in the work place, and may be a harbinger for more disabling cumulative trauma disorders. Although the cause of fatigue is multifactorial, reduced blood flow and muscle oxygenation may be the primary factor in causing muscle fatigue during low intensity muscle exertion. Muscle fatigue is defined as a reduction in muscle force production, and also occurs among astronauts who are subjected to postural constraints while performing lengthy, repetitive tasks. The objectives of this research are to: 1) develop an objective tool to study the role of decreased muscle oxygenation on muscle force production, and 2) to evaluate muscle fatigue during prolonged glovebox work.

Nuclear Positioning in Muscle Development and Disease

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Eric eFolker

2013-12-01

Full Text Available Muscle disease as a group is characterized by muscle weakness, muscle loss, and impaired muscle function. Although the phenotype is the same, the underlying cellular pathologies, and the molecular causes of these pathologies, are diverse. One common feature of many muscle disorders is the mispositioning of myonuclei. In unaffected individuals myonuclei are spaced throughout the periphery of the muscle fiber such that the distance between nuclei is maximized. However, in diseased muscles, the nuclei are often clustered within the center of the muscle cell. Although this phenotype has been acknowledged for several decades, it is often ignored as a contributor to muscle weakness. Rather, these nuclei are taken only as a sign of muscle repair. Here we review the evidence that mispositioned myonuclei are not merely a symptom of muscle disease but also a cause. Additionally, we review the working models for how myonuclei move from two different perspectives, from that of the nucleus and from that of the cytoskeleton. We further compare and contrast these mechanisms with the mechanisms of nuclear movement in other cell types both to draw general themes for nuclear movement and to identify muscle-specific considerations. Finally, we focus on factors that can be linked to muscle disease and find that genes that regulate myonuclear movement and positioning have been linked to muscular dystrophy. Although the cause-effect relationship is largely speculative, recent data indicate that the position of nuclei should no longer be considered only a means to diagnose muscle disease.

Lower limb muscle volume estimation from maximum cross-sectional area and muscle length in cerebral palsy and typically developing individuals.

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Vanmechelen, Inti M; Shortland, Adam P; Noble, Jonathan J

2018-01-01

Deficits in muscle volume may be a significant contributor to physical disability in young people with cerebral palsy. However, 3D measurements of muscle volume using MRI or 3D ultrasound may be difficult to make routinely in the clinic. We wished to establish whether accurate estimates of muscle volume could be made from a combination of anatomical cross-sectional area and length measurements in samples of typically developing young people and young people with bilateral cerebral palsy. Lower limb MRI scans were obtained from the lower limbs of 21 individuals with cerebral palsy (14.7±3years, 17 male) and 23 typically developing individuals (16.8±3.3years, 16 male). The volume, length and anatomical cross-sectional area were estimated from six muscles of the left lower limb. Analysis of Covariance demonstrated that the relationship between the length*cross-sectional area and volume was not significantly different depending on the subject group. Linear regression analysis demonstrated that the product of anatomical cross-sectional area and length bore a strong and significant relationship to the measured muscle volume (R 2 values between 0.955 and 0.988) with low standard error of the estimates of 4.8 to 8.9%. This study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coordinated development of muscles and tendon-like structures: early interactions in the Drosophila leg

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cedric esoler

2016-02-01

Full Text Available The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates during the early steps of leg development, we affect the spatial localisation of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes.

Improvement of livestock breeding strategies using physiologic and functional genomic information of the muscle regulatory factors gene family for skeletal muscle development

NARCIS (Netherlands)

Pas, te M.F.W.; Soumillon, A.

2001-01-01

A defined number of skeletal muscle fibers are formed in two separate waves during prenatal development, while postnatal growth is restricted to hypertrophic muscle fiber growth. The genes of the MRF (muscle regulatory factors) gene family, consisting of 4 structurally related transcription factors

Muscle specific microRNAs are regulated by endurance exercise in human skeletal muscle

DEFF Research Database (Denmark)

Nielsen, Søren; Scheele, Camilla; Yfanti, Christina

2010-01-01

Muscle specific miRNAs, myomiRs, have been shown to control muscle development in vitro and are differentially expressed at rest in diabetic skeletal muscle. Therefore, we investigated the expression of these myomiRs, including miR-1, miR-133a, miR-133b and miR-206 in muscle biopsies from vastus...... lateralis of healthy young males (n = 10) in relation to a hyperinsulinaemic–euglycaemic clamp as well as acute endurance exercise before and after 12 weeks of endurance training. The subjects increased their endurance capacity, VO2max (l min-1) by 17.4% (P improved insulin sensitivity by 19......, but their role in regulating human skeletal muscle adaptation remains unknown....

Tropomyosin 4 defines novel filaments in skeletal muscle associated with muscle remodelling/regeneration in normal and diseased muscle.

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Vlahovich, Nicole; Schevzov, Galina; Nair-Shaliker, Visalini; Ilkovski, Biljana; Artap, Stanley T; Joya, Josephine E; Kee, Anthony J; North, Kathryn N; Gunning, Peter W; Hardeman, Edna C

2008-01-01

The organisation of structural proteins in muscle into highly ordered sarcomeres occurs during development, regeneration and focal repair of skeletal muscle fibers. The involvement of cytoskeletal proteins in this process has been documented, with nonmuscle gamma-actin found to play a role in sarcomere assembly during muscle differentiation and also shown to be up-regulated in dystrophic muscles which undergo regeneration and repair [Lloyd et al.,2004; Hanft et al.,2006]. Here, we show that a cytoskeletal tropomyosin (Tm), Tm4, defines actin filaments in two novel compartments in muscle fibers: a Z-line associated cytoskeleton (Z-LAC), similar to a structure we have reported previously [Kee et al.,2004], and longitudinal filaments that are orientated parallel to the sarcomeric apparatus, present during myofiber growth and repair/regeneration. Tm4 is upregulated in paradigms of muscle repair including induced regeneration and focal repair and in muscle diseases with repair/regeneration features, muscular dystrophy and nemaline myopathy. Longitudinal Tm4-defined filaments also are present in diseased muscle. Transition of the Tm4-defined filaments from a longitudinal to a Z-LAC orientation is observed during the course of muscle regeneration. This Tm4-defined cytoskeleton is a marker of growth and repair/regeneration in response to injury, disease state and stress in skeletal muscle.

INVITED REVIEW: Inhibitors of myostatin as methods of enhancing muscle growth and development.

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Chen, P R; Lee, K

2016-08-01

With the increasing demand for affordable, high-quality meat, livestock and poultry producers must continually find ways to maximize muscle growth in their animals without compromising palatability of the meat products. Muscle mass relies on myoblast proliferation during prenatal or prehatch stages and fiber hypertrophy through protein synthesis and nuclei donation by satellite cells after birth or hatch. Therefore, understanding the cellular and molecular mechanisms of myogenesis and muscle development is of great interest. Myostatin is a well-known negative regulator of muscle growth and development that inhibits proliferation and differentiation in myogenic cells as well as protein synthesis in existing muscle fibers. In this review, various inhibitors of myostatin activity or signaling are examined that may be used in animal agriculture for enhancing muscle growth. Myostatin inhibitors are relevant as potential therapies for muscle-wasting diseases and muscle weakness in humans and animals. Currently, there are no commercial myostatin inhibitors for agriculture or biomedical purposes because the safest and most effective option has yet to be identified. Further investigation of myostatin inhibitors and administration strategies may revolutionize animal production and the medical field.

Benefits of dietary phytochemical supplementation on eccentric exercise-induced muscle damage: Is including antioxidants enough?

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Pereira Panza, Vilma Simões; Diefenthaeler, Fernando; da Silva, Edson Luiz

2015-09-01

The purpose of this review was to critically discuss studies that investigated the effects of supplementation with dietary antioxidant phytochemicals on recovery from eccentric exercise-induced muscle damage. The performance of physical activities that involve unaccustomed eccentric muscle actions-such as lowering a weight or downhill walking-can result in muscle damage, oxidative stress, and inflammation. These events may be accompanied by muscle weakness and delayed-onset muscle soreness. According to the current evidences, supplementation with dietary antioxidant phytochemicals appears to have the potential to attenuate symptoms associated with eccentric exercise-induced muscle damage. However, there are inconsistencies regarding the relationship between muscle damage and blood markers of oxidative stress and inflammation. Furthermore, the effectiveness of strategies appear to depend on a number of aspects inherent to phytochemical compounds as well as its food matrix. Methodological issues also may interfere with the proper interpretation of supplementation effects. Thus, the study may contribute to updating professionals involved in sport nutrition as well as highlighting the interest of scientists in new perspectives that can widen dietary strategies applied to training. Copyright © 2015 Elsevier Inc. All rights reserved.

Gene expression studies of developing bovine longissimus muscle from two different beef cattle breeds

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Byrne Keren A

2007-08-01

Full Text Available Abstract Background The muscle fiber number and fiber composition of muscle is largely determined during prenatal development. In order to discover genes that are involved in determining adult muscle phenotypes, we studied the gene expression profile of developing fetal bovine longissimus muscle from animals with two different genetic backgrounds using a bovine cDNA microarray. Fetal longissimus muscle was sampled at 4 stages of myogenesis and muscle maturation: primary myogenesis (d 60, secondary myogenesis (d 135, as well as beginning (d 195 and final stages (birth of functional differentiation of muscle fibers. All fetuses and newborns (total n = 24 were from Hereford dams and crossed with either Wagyu (high intramuscular fat or Piedmontese (GDF8 mutant sires, genotypes that vary markedly in muscle and compositional characteristics later in postnatal life. Results We obtained expression profiles of three individuals for each time point and genotype to allow comparisons across time and between sire breeds. Quantitative reverse transcription-PCR analysis of RNA from developing longissimus muscle was able to validate the differential expression patterns observed for a selection of differentially expressed genes, with one exception. We detected large-scale changes in temporal gene expression between the four developmental stages in genes coding for extracellular matrix and for muscle fiber structural and metabolic proteins. FSTL1 and IGFBP5 were two genes implicated in growth and differentiation that showed developmentally regulated expression levels in fetal muscle. An abundantly expressed gene with no functional annotation was found to be developmentally regulated in the same manner as muscle structural proteins. We also observed differences in gene expression profiles between the two different sire breeds. Wagyu-sired calves showed higher expression of fatty acid binding protein 5 (FABP5 RNA at birth. The developing longissimus muscle of

Control approach development for variable recruitment artificial muscles

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Jenkins, Tyler E.; Chapman, Edward M.; Bryant, Matthew

2016-04-01

This study characterizes hybrid control approaches for the variable recruitment of fluidic artificial muscles with double acting (antagonistic) actuation. Fluidic artificial muscle actuators have been explored by researchers due to their natural compliance, high force-to-weight ratio, and low cost of fabrication. Previous studies have attempted to improve system efficiency of the actuators through variable recruitment, i.e. using discrete changes in the number of active actuators. While current variable recruitment research utilizes manual valve switching, this paper details the current development of an online variable recruitment control scheme. By continuously controlling applied pressure and discretely controlling the number of active actuators, operation in the lowest possible recruitment state is ensured and working fluid consumption is minimized. Results provide insight into switching control scheme effects on working fluids, fabrication material choices, actuator modeling, and controller development decisions.

Gravity Plays an Important Role in Muscle Development and the Differentiation of Contractile Protein Phenotype

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Adams, Gregory A.; Haddad, Fadia; Baldwin, Kenneth M.

2003-01-01

Several muscles in the body exist mainly to work against gravity. Whether gravity is important in the development of these muscles is not known. By examining the basic proteins that compose muscle, questions about the role of gravity in muscle development can be answered. Myosin heavy chains (MHCs) are a family of proteins critically important for muscle contraction. Several types of MHCs exist (e.g., neonatal, slow, fast), and each type is produced by a particular gene. Neonatal MHCs are produced early in life. Slow MHCs are important in antigravity muscles, and fast MHCs are found in fast-twitch power muscles. The gene that is turned on or expressed will determine which MHC is produced. Early in development, antigravity skeletal muscles (muscles that work against gravity) normally produce a combination of the neonatal/embryonic MHCs. The expression of these primitive MHCs is repressed early in development; and the adult slow and fast MHC genes become fully expressed. We tested the hypothesis that weightbearing activity is critical for inducing the normal expression of the slow MHC gene typically expressed in adult antigravity muscles. Also, we hypothesized that thyroid hormone, but not opposition to gravity, is necessary for expressing the adult fast IIb MHC gene essential for high-intensity muscle performance. Groups of normal thyroid and thyroid-deficient neonatal rats were studied after their return from the 16-day Neurolab mission and compared to matched controls. The results suggest: (1) Weightlessness impaired body and limb skeletal muscle growth in both normal and thyroid-deficient animals. Antigravity muscles were impaired more than those used primarily for locomotion andor nonweightbearing activity. (2) Systemic and muscle expression of insulin-like growth factor-I (IGF-I), an important body and tissue growth factor, was depressed in flight animals. (3) Normal slow, type I MHC gene expression was markedly repressed in the normal thyroid flight group. (4

Development of the epaxial muscles in the human embryo

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Mekonen, Hayelom K.; Hikspoors, Jill P. J. M.; Mommen, Greet; Eleonore KÖhler, S.; Lamers, Wouter H.

2016-01-01

Although the intrinsic muscles of the back are defined by their embryological origin and innervation pattern, no detailed study on their development is available. Human embryos (5-10 weeks development) were studied, using Amira3D® reconstruction and Cinema4D® remodeling software for visualization.

Expression of Pannexin 1 and Pannexin 3 during skeletal muscle development, regeneration, and Duchenne muscular dystrophy.

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Pham, Tammy L; St-Pierre, Marie-Eve; Ravel-Chapuis, Aymeric; Parks, Tara E C; Langlois, Stéphanie; Penuela, Silvia; Jasmin, Bernard J; Cowan, Kyle N

2018-05-10

Pannexin 1 (Panx1) and Pannexin 3 (Panx3) are single membrane channels recently implicated in myogenic commitment, as well as myoblast proliferation and differentiation in vitro. However, their expression patterns during skeletal muscle development and regeneration had yet to be investigated. Here, we show that Panx1 levels increase during skeletal muscle development becoming highly expressed together with Panx3 in adult skeletal muscle. In adult mice, Panx1 and Panx3 were differentially expressed in fast- and slow-twitch muscles. We also report that Panx1/PANX1 and Panx3/PANX3 are co-expressed in mouse and human satellite cells, which play crucial roles in skeletal muscle regeneration. Interestingly, Panx1 and Panx3 levels were modulated in muscle degeneration/regeneration, similar to the pattern seen during skeletal muscle development. As Duchenne muscular dystrophy is characterized by skeletal muscle degeneration and impaired regeneration, we next used mild and severe mouse models of this disease and found a significant dysregulation of Panx1 and Panx3 levels in dystrophic skeletal muscles. Together, our results are the first demonstration that Panx1 and Panx3 are differentially expressed amongst skeletal muscle types with their levels being highly modulated during skeletal muscle development, regeneration, and dystrophy. These findings suggest that Panx1 and Panx3 channels may play important and distinct roles in healthy and diseased skeletal muscles. © 2018 Wiley Periodicals, Inc.

Cis-Natural Antisense Transcripts Are Mainly Co-expressed with Their Sense Transcripts and Primarily Related to Energy Metabolic Pathways during Muscle Development.

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Zhao, Yunxia; Hou, Ye; Zhao, Changzhi; Liu, Fei; Luan, Yu; Jing, Lu; Li, Xinyun; Zhu, Mengjin; Zhao, Shuhong

2016-01-01

Cis-natural antisense transcripts (cis-NATs) are a new class of RNAs identified in various species. However, the biological functions of cis-NATs are largely unknown. In this study, we investigated the transcriptional characteristics and functions of cis-NATs in the muscle tissue of lean Landrace and indigenous fatty Lantang pigs. In total, 3,306 cis-NATs of 2,469 annotated genes were identified in the muscle tissue of pigs. More than 1,300 cis-NATs correlated with their sense genes at the transcriptional level, and approximately 80% of them were co-expressed in the two breeds. Furthermore, over 1,200 differentially expressed cis-NATs were identified during muscle development. Function annotation showed that the cis-NATs participated in muscle development mainly by co-expressing with genes involved in energy metabolic pathways, including citrate cycle (TCA cycle), glycolysis or gluconeogenesis, mitochondrial activation and so on. Moreover, these cis-NATs and their sense genes abruptly increased at the transition from the late fetal stages to the early postnatal stages and then decreased along with muscle development. In conclusion, the cis-NATs in the muscle tissue of pigs were identified and determined to be mainly co-expressed with their sense genes. The co-expressed cis-NATs and their sense gene were primarily related to energy metabolic pathways during muscle development in pigs. Our results offered novel evidence on the roles of cis-NATs during the muscle development of pigs.

Development and production of an oligonucleotide MuscleChip: use for validation of ambiguous ESTs

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Lanfranchi Gerolamo

2002-10-01

Full Text Available Abstract Background We describe the development, validation, and use of a highly redundant 120,000 oligonucleotide microarray (MuscleChip containing 4,601 probe sets representing 1,150 known genes expressed in muscle and 2,075 EST clusters from a non-normalized subtracted muscle EST sequencing project (28,074 EST sequences. This set included 369 novel EST clusters showing no match to previously characterized proteins in any database. Each probe set was designed to contain 20–32 25 mer oligonucleotides (10–16 paired perfect match and mismatch probe pairs per gene, with each probe evaluated for hybridization kinetics (Tm and similarity to other sequences. The 120,000 oligonucleotides were synthesized by photolithography and light-activated chemistry on each microarray. Results Hybridization of human muscle cRNAs to this MuscleChip (33 samples showed a correlation of 0.6 between the number of ESTs sequenced in each cluster and hybridization intensity. Out of 369 novel EST clusters not showing any similarity to previously characterized proteins, we focused on 250 EST clusters that were represented by robust probe sets on the MuscleChip fulfilling all stringent rules. 102 (41% were found to be consistently "present" by analysis of hybridization to human muscle RNA, of which 40 ESTs (39% could be genome anchored to potential transcription units in the human genome sequence. 19 ESTs of the 40 ESTs were furthermore computer-predicted as exons by one or more than three gene identification algorithms. Conclusion Our analysis found 40 transcriptionally validated, genome-anchored novel EST clusters to be expressed in human muscle. As most of these ESTs were low copy clusters (duplex and triplex in the original 28,000 EST project, the identification of these as significantly expressed is a robust validation of the transcript units that permits subsequent focus on the novel proteins encoded by these genes.

Anthropogenic changes in sodium affect neural and muscle development in butterflies

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Snell-Rood, Emilie C.; Espeset, Anne; Boser, Christopher J.; White, William A.; Smykalski, Rhea

2014-01-01

The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5–30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates. PMID:24927579

Anthropogenic changes in sodium affect neural and muscle development in butterflies.

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Snell-Rood, Emilie C; Espeset, Anne; Boser, Christopher J; White, William A; Smykalski, Rhea

2014-07-15

The development of organisms is changing drastically because of anthropogenic changes in once-limited nutrients. Although the importance of changing macronutrients, such as nitrogen and phosphorus, is well-established, it is less clear how anthropogenic changes in micronutrients will affect organismal development, potentially changing dynamics of selection. We use butterflies as a study system to test whether changes in sodium availability due to road salt runoff have significant effects on the development of sodium-limited traits, such as neural and muscle tissue. We first document how road salt runoff can elevate sodium concentrations in the tissue of some plant groups by 1.5-30 times. Using monarch butterflies reared on roadside- and prairie-collected milkweed, we then show that road salt runoff can result in increased muscle mass (in males) and neural investment (in females). Finally, we use an artificial diet manipulation in cabbage white butterflies to show that variation in sodium chloride per se positively affects male flight muscle and female brain size. Variation in sodium not only has different effects depending on sex, but also can have opposing effects on the same tissue: across both species, males increase investment in flight muscle with increasing sodium, whereas females show the opposite pattern. Taken together, our results show that anthropogenic changes in sodium availability can affect the development of traits in roadside-feeding herbivores. This research suggests that changing micronutrient availability could alter selection on foraging behavior for some roadside-developing invertebrates.

Obscurin Depletion Impairs Organization of Skeletal Muscle in Developing Zebrafish Embryos

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Maide Ö. Raeker

2011-01-01

Full Text Available During development, skeletal myoblasts differentiate into myocytes and skeletal myotubes with mature contractile structures that are precisely oriented with respect to surrounding cells and tissues. Establishment of this highly ordered structure requires reciprocal interactions between the differentiating myocytes and the surrounding extracellular matrix to form correctly positioned and well-organized attachments from the skeletal muscle to the bony skeleton. Using the developing zebrafish embryo as a model, we examined the relationship between new myofibril assembly and the organization of the membrane domains involved in cell-extracellular matrix interactions. We determined that depletion of obscurin, a giant muscle protein, resulted in irregular cell morphology and disturbed extracellular matrix organization during skeletal muscle development. The resulting impairment of myocyte organization was associated with disturbance of the internal architecture of the myocyte suggesting that obscurin participates in organizing the internal structure of the myocyte and translating those structural cues to surrounding cells and tissues.

Obscurin Depletion Impairs Organization of Skeletal Muscle in Developing Zebrafish Embryos

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Raeker, Maide Ö.; Russell, Mark W.

2011-01-01

During development, skeletal myoblasts differentiate into myocytes and skeletal myotubes with mature contractile structures that are precisely oriented with respect to surrounding cells and tissues. Establishment of this highly ordered structure requires reciprocal interactions between the differentiating myocytes and the surrounding extracellular matrix to form correctly positioned and well-organized attachments from the skeletal muscle to the bony skeleton. Using the developing zebrafish embryo as a model, we examined the relationship between new myofibril assembly and the organization of the membrane domains involved in cell-extracellular matrix interactions. We determined that depletion of obscurin, a giant muscle protein, resulted in irregular cell morphology and disturbed extracellular matrix organization during skeletal muscle development. The resulting impairment of myocyte organization was associated with disturbance of the internal architecture of the myocyte suggesting that obscurin participates in organizing the internal structure of the myocyte and translating those structural cues to surrounding cells and tissues. PMID:22190853

Nickel affects gill and muscle development in oriental fire-bellied toad (Bombina orientalis) embryos

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Park, Chan Jin; Song, Sang Ha; Kim, Dae Han; Gye, Myung Chan, E-mail: mcgye@hanyang.ac.kr

2017-01-15

Highlights: • Nickel inhibited the development of external gill in B. orientalis embryos. • The 168 h LC{sub 50} and EC{sub 50} values of nickel were 33.8 and 5.4 μM, respectively, in embryos. • Nickel induced abnormal tail development of embryos. • NF stage 26–31 was the most sensitive window for embryos to nickel exposure. • Nickel affected the calcium-dependent myogenic gene expression in embryos. - Abstract: The developmental toxicity of nickel was examined in the embryos of Bombina orientalis, a common amphibian in Korea. Based on a standard frog embryo teratogenesis assay, the LC{sub 50} and EC{sub 50} for malformation of nickel after 168 h of treatment were 33.8 μM and 5.4 μM, respectively. At a lethal concentration (100 μM), nickel treatment decreased the space between gill filaments and caused epithelial swelling and abnormal fusion of gill filaments. These findings suggest that nickel affects the functional development of gills, leading to embryonic death. At sublethal concentrations (1–10 μM), nickel produced multiple embryonic abnormalities, including bent tail and tail dysplasia. At 10 μM, nickel significantly decreased tail length and tail muscle fiber density in tadpoles, indicating inhibition of myogenic differentiation. Before hatching, the pre-muscular response to muscular response stages (stages 26–31) were the most sensitive period to nickel with respect to tail muscle development. During these stages, MyoD mRNA was upregulated, whereas myogenic regulatory factor 4 mRNA was downregulated by 0.1 μM nickel. Calcium-dependent kinase activities in muscular response stage embryos were significantly decreased by nickel, whereas these activities were restored by exogenous calcium. In tadpoles, 10 μM nickel significantly decreased the expression of the myosin heavy chain and the 12/101 muscle marker protein in the tail. Expression was restored by exogenous calcium. Our results indicate that nickel affects muscle development by

Physiological and methodological aspects of rate of force development assessment in human skeletal muscle.

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Rodríguez-Rosell, David; Pareja-Blanco, Fernando; Aagaard, Per; González-Badillo, Juan José

2017-12-20

Rate of force development (RFD) refers to the ability of the neuromuscular system to increase contractile force from a low or resting level when muscle activation is performed as quickly as possible, and it is considered an important muscle strength parameter, especially for athletes in sports requiring high-speed actions. The assessment of RFD has been used for strength diagnosis, to monitor the effects of training interventions in both healthy populations and patients, discriminate high-level athletes from those of lower levels, evaluate the impairment in mechanical muscle function after acute bouts of eccentric muscle actions and estimate the degree of fatigue and recovery after acute exhausting exercise. Notably, the evaluation of RFD in human skeletal muscle is a complex task as influenced by numerous distinct methodological factors including mode of contraction, type of instruction, method used to quantify RFD, devices used for force/torque recording and ambient temperature. Another important aspect is our limited understanding of the mechanisms underpinning rapid muscle force production. Therefore, this review is primarily focused on (i) describing the main mechanical characteristics of RFD; (ii) analysing various physiological factors that influence RFD; and (iii) presenting and discussing central biomechanical and methodological factors affecting the measurement of RFD. The intention of this review is to provide more methodological and analytical coherency on the RFD concept, which may aid to clarify the thinking of coaches and sports scientists in this area. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Effect of heparan sulfate and gold nanoparticles on muscle development during embryogenesis

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Zielinska, Marlena; Sawosz, Ewa; Grodzik, Marta

2011-01-01

Purpose: It was hypothesized that heparan sulfate (HS) as an essential compound for myogenesis and nanoparticles of gold (nano-Au) ashighly reactive compounds can affect muscle development as a consequence of molecular regulation of muscle cell formation, and that these effects may be enhanced by...

Development of active, nanoparticle, antimicrobial technologies for muscle-based packaging applications.

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Morris, Michael A; Padmanabhan, Sibu C; Cruz-Romero, Malco C; Cummins, Enda; Kerry, Joseph P

2017-10-01

Fresh and processed muscle-based foods are highly perishable food products and packaging plays a crucial role in providing containment so that the full effect of preservation can be achieved through the provision of shelf-life extension. Conventional packaging materials and systems have served the industry well, however, greater demands are being placed upon industrial packaging formats owing to the movement of muscle-based products to increasingly distant markets, as well as increased customer demands for longer product shelf-life and storage capability. Consequently, conventional packaging materials and systems will have to evolve to meet these challenges. This review presents some of the new strategies that have been developed by employing novel nanotechnological concepts which have demonstrated some promise in significantly extending the shelf-life of muscle-based foods by providing commercially-applicable, antimicrobially-active, smart packaging solutions. The primary focus of this paper is applied to subject aspects, such as; material chemistries employed, forming methods utilised, interactions of the packaging functionalities including nanomaterials employed with polymer substrates and how such materials ultimately affect microbes. In order that such materials become industrially feasible, it is important that safe, stable and commercially-viable packaging materials are shown to be producible and effective in order to gain public acceptance, legislative approval and industrial adoption. Copyright © 2017. Published by Elsevier Ltd.

Pathophysiology of muscle contractures in cerebral palsy.

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Mathewson, Margie A; Lieber, Richard L

2015-02-01

Patients with cerebral palsy present with a variety of adaptations to muscle structure and function. These pathophysiologic symptoms include functional deficits such as decreased force production and range of motion, in addition to changes in muscle structure such as decreased muscle belly size, increased sarcomere length, and altered extracellular matrix structure and composition. On a cellular level, patients with cerebral palsy have fewer muscle stem cells, termed satellite cells, and altered gene expression. Understanding the nature of these changes may present opportunities for the development of new muscle treatment therapies. Published by Elsevier Inc.

Passive stiffness of rat skeletal muscle undernourished during fetal development

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Ana Elisa Toscano

2010-01-01

Full Text Available OBJECTIVES: The aim of the study was to investigate the effect of fetal undernutrition on the passive mechanical properties of skeletal muscle of weaned and young adult rats. INTRODUCTION: A poor nutrition supply during fetal development affects physiological functions of the fetus. From a mechanical point of view, skeletal muscle can be also characterized by its resistance to passive stretch. METHODS: Male Wistar rats were divided into two groups according to their mother's diet during pregnancy: a control group (mothers fed a 17% protein diet and an isocaloric low-protein group (mothers fed a 7.8% protein diet. At birth, all mothers received a standardized meal ad libitum. At the age of 25 and 90 days, the soleus muscle and extensor digitorum longus (EDL muscles were removed in order to test the passive mechanical properties. A first mechanical test consisted of an incremental stepwise extension test using fast velocity stretching (500 mm/s enabling us to measure, for each extension stepwise, the dynamic stress (σd and the steady stress (σs. A second test consisted of a slow velocity stretch in order to calculate normalized stiffness and tangent modulus from the stress-strain relationship. RESULTS: The results for the mechanical properties showed an important increase in passive stiffness in both the soleus and EDL muscles in weaned rat. In contrast, no modification was observed in young adult rats. CONCLUSIONS: The increase in passive stiffness in skeletal muscle of weaned rat submitted to intrauterine undernutrition it is most likely due to changes in muscle passive stiffness.

Force encoding in muscle spindles during stretch of passive muscle.

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Kyle P Blum

2017-09-01

Full Text Available Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle

Force encoding in muscle spindles during stretch of passive muscle.

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Blum, Kyle P; Lamotte D'Incamps, Boris; Zytnicki, Daniel; Ting, Lena H

2017-09-01

Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs) of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt) predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening) of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle lengthening conditions

Vitamin D, muscle and bone: Integrating effects in development, aging and injury.

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Girgis, Christian M; Baldock, Paul A; Downes, Michael

2015-07-15

Beyond the established effects of muscle loading on bone, a complex network of hormones and growth factors integrates these adjacent tissues. One such hormone, vitamin D, exerts broad-ranging effects in muscle and bone calcium handling, differentiation and development. Vitamin D also modulates muscle and bone-derived hormones, potentially facilitating cross-talk between these tissues. In the clinical setting, vitamin D deficiency or mutations of the vitamin D receptor result in generalized atrophy of muscle and bone, suggesting coordinated effects of vitamin D at these sites. In this review, we discuss emerging evidence that vitamin D exerts specific effects throughout the life of the musculoskeletal system - in development, aging and injury. From this holistic viewpoint, we offer new insights into an old debate: whether vitamin D's effects in the musculoskeletal system are direct via local VDR signals or indirect via its systemic effects in calcium and phosphate homeostasis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The homeobox gene Msx in development and transdifferentiation of jellyfish striated muscle.

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Galle, Sabina; Yanze, Nathalie; Seipel, Katja

2005-01-01

Bilaterian Msx homeobox genes are generally expressed in areas of cell proliferation and in association with multipotent progenitor cells. Likewise, jellyfish Msx is expressed in progenitor cells of the developing entocodon, a cell layer giving rise to the striated and smooth muscles of the medusa. However, in contrast to the bilaterian homologs, Msx gene expression is maintained at high levels in the differentiated striated muscle of the medusa in vivo and in vitro. This tissue exhibits reprogramming competence. Upon induction, the Msx gene is immediately switched off in the isolated striated muscle undergoing transdifferentiation, to be upregulated again in the emerging smooth muscle cells which, in a stem cell like manner, undergo quantal cell divisions producing two cell types, a proliferating smooth muscle cell and a differentiating nerve cell. This study indicates that the Msx protein may be a key component of the reprogramming machinery responsible for the extraordinary transdifferentation and regeneration potential of striated muscle in the hydrozoan jellyfish.

Effect of taurine and gold nanoparticles on the morphological and molecular characteristics of muscle development during chicken embryogenesis

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Zielinska, Marlena; Sawosz, Ewa; Grodzik, Marta

2012-01-01

The objective of the present investigation was to evaluate the effects of taurine and Au nanoparticles on the expression of genes related to embryonic muscle development and on the morphological characteristics of muscles. Fertilised chicken eggs (n = 160) were randomly divided into four groups......: without injection (Control) and with injection of Au nanoparticles (NanoAu), taurine (Tau) or Au nanoparticles with taurine (NanoAu + Tau). The experimental solutions were given in ovo, on the third day of incubation, by injecting 0.3 ml of the experimental solution into the air sack. The embryos were...... evaluated on the 20th day of incubation. The methods included gene expression at the mRNA and protein levels, immunohistochemistry, histology and microscopy. In groups NanoAu, Tau and NanoAu + Tau, the muscle structure and the number of muscle cells were affected. Furthermore, taurine increased fibre...

Development of the Platysma Muscle and the Superficial Musculoaponeurotic System (Human Specimens at 8–17 Weeks of Development

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C. De la Cuadra-Blanco

2013-01-01

Full Text Available There is controversy regarding the description of the different regions of the face of the superficial musculoaponeurotic system (SMAS and its relationship with the superficial mimetic muscles. The purpose of this study is to analyze the development of the platysma muscle and the SMAS in human specimens at 8–17 weeks of development using an optical microscope. Furthermore, we propose to study the relationship of the anlage of the SMAS and the neighbouring superficial mimetic muscles. The facial musculature derives from the mesenchyme of the second arch and migrates towards the different regions of the face while forming premuscular laminae. During the 8th week of development, the cervical, infraorbital, mandibular, and temporal laminae are observed to be on the same plane. The platysma muscle derives from the cervical lamina and its mandibular extension enclosing the lower part of the parotid region and the cheek, while the SMAS derives from the upper region. During the period of development analyzed in this study, we have observed no continuity between the anlage of the SMAS and that of the superficial layer of the temporal fascia and the zygomaticus major muscle. Nor have we observed any structure similar to the SMAS in the labial region.

Engineered matrices for skeletal muscle satellite cell engraftment and function.

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Han, Woojin M; Jang, Young C; García, Andrés J

2017-07-01

Regeneration of traumatically injured skeletal muscles is severely limited. Moreover, the regenerative capacity of skeletal muscle declines with aging, further exacerbating the problem. Recent evidence supports that delivery of muscle satellite cells to the injured muscles enhances muscle regeneration and reverses features of aging, including reduction in muscle mass and regenerative capacity. However, direct delivery of satellite cells presents a challenge at a translational level due to inflammation and donor cell death, motivating the need to develop engineered matrices for muscle satellite cell delivery. This review will highlight important aspects of satellite cell and their niche biology in the context of muscle regeneration, and examine recent progresses in the development of engineered cell delivery matrices designed for skeletal muscle regeneration. Understanding the interactions of muscle satellite cells and their niche in both native and engineered systems is crucial to developing muscle pathology-specific cell- and biomaterial-based therapies. Copyright © 2016 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

Skeletal muscle ATP turnover and muscle fiber conduction velocity are elevated at higher muscle temperatures during maximal power output development in humans.

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Gray, Stuart R; De Vito, Giuseppe; Nimmo, Myra A; Farina, Dario; Ferguson, Richard A

2006-02-01

The effect of temperature on skeletal muscle ATP turnover and muscle fiber conduction velocity (MFCV) was studied during maximal power output development in humans. Eight male subjects performed a 6-s maximal sprint on a mechanically braked cycle ergometer under conditions of normal (N) and elevated muscle temperature (ET). Muscle temperature was passively elevated through the combination of hot water immersion and electric blankets. Anaerobic ATP turnover was calculated from analysis of muscle biopsies obtained before and immediately after exercise. MFCV was measured during exercise using surface electromyography. Preexercise muscle temperature was 34.2 degrees C (SD 0.6) in N and 37.5 degrees C (SD 0.6) in ET. During ET, the rate of ATP turnover for phosphocreatine utilization [temperature coefficient (Q10) = 3.8], glycolysis (Q10 = 1.7), and total anaerobic ATP turnover [Q10 = 2.7; 10.8 (SD 1.9) vs. 14.6 mmol x kg(-1) (dry mass) x s(-1) (SD 2.3)] were greater than during N (P < 0.05). MFCV was also greater in ET than in N [3.79 (SD 0.47) to 5.55 m/s (SD 0.72)]. Maximal power output (Q10 = 2.2) and pedal rate (Q10 = 1.6) were greater in ET compared with N (P < 0.05). The Q10 of maximal and mean power were correlated (P < 0.05; R = 0.82 and 0.85, respectively) with the percentage of myosin heavy chain type IIA. The greater power output obtained with passive heating was achieved through an elevated rate of anaerobic ATP turnover and MFCV, possibly due to a greater effect of temperature on power production of fibers, with a predominance of myosin heavy chain IIA at the contraction frequencies reached.

Cranial muscle development in the model organism ambystoma mexicanum: implications for tetrapod and vertebrate comparative and evolutionary morphology and notes on ontogeny and phylogeny.

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Ziermann, Janine M; Diogo, Rui

2013-07-01

There is still confusion about the homology of several cranial muscles in salamanders with those of other vertebrates. This is true, in part, because of the fact that many muscles present in early ontogeny of amphibians disappear during development and specifically during metamorphosis. Resolving this confusion is important for the understanding of the comparative and evolutionary morphology of vertebrates and tetrapods because amphibians are the phylogenetically most plesiomorphic tetrapods, concerning for example their myology, and include two often used model organisms, Xenopus laevis (anuran) and Ambystoma mexicanum (urodele). Here we provide the first detailed report of the cranial muscle development in axolotl from early ontogenetic stages to the adult stage. We describe different and complementary types of general muscle morphogenetic gradients in the head: from anterior to posterior, from lateral to medial, and from origin to insertion. Furthermore, even during the development of neotenic salamanders such as axolotls, various larval muscles become indistinct, contradicting the commonly accepted view that during ontogeny the tendency is mostly toward the differentiation of muscles. We provide an updated comparison between these muscles and the muscles of other vertebrates, a discussion of the homologies and evolution, and show that the order in which the muscles appear during axolotl ontogeny is in general similar to their appearance in phylogeny (e.g. differentiation of adductor mandibulae muscles from one anlage to four muscles), with only a few remarkable exceptions, as for example the dilatator laryngis that appears evolutionary later but in the development before the intermandibularis. Copyright © 2013 Wiley Periodicals, Inc.

Increase in relative skeletal muscle mass over time and its inverse association with metabolic syndrome development: a 7-year retrospective cohort study.

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Kim, Gyuri; Lee, Seung-Eun; Jun, Ji Eun; Lee, You-Bin; Ahn, Jiyeon; Bae, Ji Cheol; Jin, Sang-Man; Hur, Kyu Yeon; Jee, Jae Hwan; Lee, Moon-Kyu; Kim, Jae Hyeon

2018-02-05

Skeletal muscle mass was negatively associated with metabolic syndrome prevalence in previous cross-sectional studies. The aim of this study was to investigate the impact of baseline skeletal muscle mass and changes in skeletal muscle mass over time on the development of metabolic syndrome in a large population-based 7-year cohort study. A total of 14,830 and 11,639 individuals who underwent health examinations at the Health Promotion Center at Samsung Medical Center, Seoul, Korea were included in the analyses of baseline skeletal muscle mass and those changes from baseline over 1 year, respectively. Skeletal muscle mass was estimated by bioelectrical impedance analysis and was presented as a skeletal muscle mass index (SMI), a body weight-adjusted appendicular skeletal muscle mass value. Using Cox regression models, hazard ratio for developing metabolic syndrome associated with SMI values at baseline or changes of SMI over a year was analyzed. During 7 years of follow-up, 20.1% of subjects developed metabolic syndrome. Compared to the lowest sex-specific SMI tertile at baseline, the highest sex-specific SMI tertile showed a significant inverse association with metabolic syndrome risk (adjusted hazard ratio [AHR] = 0.61, 95% confidence interval [CI] 0.54-0.68). Furthermore, compared with SMI changes metabolic syndrome development were 0.87 (95% CI 0.78-0.97) for 0-1% changes and 0.67 (0.56-0.79) for > 1% changes in SMI over 1 year after additionally adjusting for baseline SMI and glycometabolic parameters. An increase in relative skeletal muscle mass over time has a potential preventive effect on developing metabolic syndrome, independently of baseline skeletal muscle mass and glycometabolic parameters.

Development and evaluation of a removable tissue-engineered muscle with artificial tendons.

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Nakamura, Tomohiro; Takagi, Shunya; Kamon, Takafumi; Yamasaki, Ken-Ichi; Fujisato, Toshia

2017-02-01

Tissue-engineered skeletal muscles were potentially useful as physiological and biochemical in vitro models. Currently, most of the similar models were constructed without tendons. In this study, we aimed to develop a simple, highly versatile tissue-engineered muscle with artificial tendons, and to evaluate the contractile, histological and molecular dynamics during differentiation. C2C12 cells were embedded in a cold type-І collagen gel and placed between two artificial tendons on a silicone sheet. The construct shrank and tightly attached to the artificial tendons with differentiation, finally detaching from the silicone sheet within 1 week of culture onset. We successfully developed a tissue-engineered skeletal muscle with two artificial tendons from C2C12 myoblasts embedded in type-І collagen gel. The isometric twitch contractile force (TCF) significantly increased during differentiation. Time to Peak Tension (TPT) and Half-Relaxation Time (1/2RT) were significantly shortened during differentiation. Myogenic regulatory factors were maximally expressed at 2 weeks, and subsequently decreased at 3 weeks of culture. Histological analysis indicated that myotube formation increased markedly from 2 weeks and well-ordered sarcomere structures were observed on the surface of the 3D engineered muscle at 3 weeks of culture. These results suggested that robust muscle structure occurred by 3 weeks in the tissue-engineered skeletal muscle. Moreover, during the developmental process, the artificial tendons might contribute to well-ordered sarcomere formation. Our results indicated that this simple culture system could be used to evaluate the effects of various pharmacological and mechanical cues on muscle contractility in a variety of research areas. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Artificial Muscles: Mechanisms, Applications, and Challenges.

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Mirvakili, Seyed M; Hunter, Ian W

2018-02-01

The area of artificial muscle is a highly interdisciplinary field of research that has evolved rapidly in the last 30 years. Recent advances in nanomaterial fabrication and characterization, specifically carbon nanotubes and nanowires, have had major contributions in the development of artificial muscles. However, what can artificial muscles really do for humans? This question is considered here by first examining nature's solutions to this design problem and then discussing the structure, actuation mechanism, applications, and limitations of recently developed artificial muscles, including highly oriented semicrystalline polymer fibers; nanocomposite actuators; twisted nanofiber yarns; thermally activated shape-memory alloys; ionic-polymer/metal composites; dielectric-elastomer actuators; conducting polymers; stimuli-responsive gels; piezoelectric, electrostrictive, magnetostrictive, and photostrictive actuators; photoexcited actuators; electrostatic actuators; and pneumatic actuators. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular events underlying skeletal muscle atrophy and the development of effective countermeasures

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Booth, F. W.; Criswell, D. S.

1997-01-01

Skeletal muscle adapts to loading; atrophying when exposed to unloading on Earth or in spaceflight. Significant atrophy (decreases in muscle fiber cross-section of 11-24%) in humans has been noted after only 5 days in space. Since muscle strength is determined both by muscle cross-section and synchronization of motor unit recruitment, a loss in muscle size weakens astronauts, which would increase risks to their safety if an emergency required maximal muscle force. Numerous countermeasures have been tested to prevent atrophy. Resistant exercise together with growth hormone and IGF-I are effective countermeasures to unloading as most atrophy is prevented in animal models. The loss of muscle protein is due to an early decrease in protein synthesis rate and a later increase in protein degradation. The initial decrease in protein synthesis is a result of decreased protein translation, caused by a prolongation in the elongation rate. A decrease in HSP70 by a sight increase in ATP may be the factors prolonging elongation rate. Increases in the activities of proteolytic enzymes and in ubiquitin contribute to the increased protein degradation rate in unloaded muscle. Numerous mRNA concentrations have been shown to be altered in unloaded muscles. Decreases in mRNAs for contractile proteins usually occur after the initial fall in protein synthesis rates. Much additional research is needed to determine the mechanism by which muscle senses the absence of gravity with an adaptive atrophy. The development of effective countermeasures to unloading atrophy will require more research.

Can Measured Synergy Excitations Accurately Construct Unmeasured Muscle Excitations?

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Bianco, Nicholas A; Patten, Carolynn; Fregly, Benjamin J

2018-01-01

Accurate prediction of muscle and joint contact forces during human movement could improve treatment planning for disorders such as osteoarthritis, stroke, Parkinson's disease, and cerebral palsy. Recent studies suggest that muscle synergies, a low-dimensional representation of a large set of muscle electromyographic (EMG) signals (henceforth called "muscle excitations"), may reduce the redundancy of muscle excitation solutions predicted by optimization methods. This study explores the feasibility of using muscle synergy information extracted from eight muscle EMG signals (henceforth called "included" muscle excitations) to accurately construct muscle excitations from up to 16 additional EMG signals (henceforth called "excluded" muscle excitations). Using treadmill walking data collected at multiple speeds from two subjects (one healthy, one poststroke), we performed muscle synergy analysis on all possible subsets of eight included muscle excitations and evaluated how well the calculated time-varying synergy excitations could construct the remaining excluded muscle excitations (henceforth called "synergy extrapolation"). We found that some, but not all, eight-muscle subsets yielded synergy excitations that achieved >90% extrapolation variance accounted for (VAF). Using the top 10% of subsets, we developed muscle selection heuristics to identify included muscle combinations whose synergy excitations achieved high extrapolation accuracy. For 3, 4, and 5 synergies, these heuristics yielded extrapolation VAF values approximately 5% lower than corresponding reconstruction VAF values for each associated eight-muscle subset. These results suggest that synergy excitations obtained from experimentally measured muscle excitations can accurately construct unmeasured muscle excitations, which could help limit muscle excitations predicted by muscle force optimizations.

Muscle force depends on the amount of transversal muscle loading.

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Siebert, Tobias; Till, Olaf; Stutzig, Norman; Günther, Michael; Blickhan, Reinhard

2014-06-03

Skeletal muscles are embedded in an environment of other muscles, connective tissue, and bones, which may transfer transversal forces to the muscle tissue, thereby compressing it. In a recent study we demonstrated that transversal loading of a muscle with 1.3Ncm(-2) reduces maximum isometric force (Fim) and rate of force development by approximately 5% and 25%, respectively. The aim of the present study was to examine the influence of increasing transversal muscle loading on contraction dynamics. Therefore, we performed isometric experiments on rat M. gastrocnemius medialis (n=9) without and with five different transversal loads corresponding to increasing pressures of 1.3Ncm(-2) to 5.3Ncm(-2) at the contact area between muscle and load. Muscle loading was induced by a custom-made plunger which was able to move in transversal direction. Increasing transversal muscle loading resulted in an almost linear decrease in muscle force from 4.8±1.8% to 12.8±2% Fim. Compared to an unloaded isometric contraction, rate of force development decreased from 20.2±4.0% at 1.3Ncm(-2) muscle loading to 34.6±5.7% at 5.3Ncm(-2). Experimental observation of the impact of transversal muscle loading on contraction dynamics may help to better understand muscle tissue properties. Moreover, applying transversal loads to muscles opens a window to analyze three-dimensional muscle force generation. Data presented in this study may be important to develop and validate muscle models which enable simulation of muscle contractions under compression and enlighten the mechanisms behind. Copyright © 2014 Elsevier Ltd. All rights reserved.

Differential rigor development in red and white muscle revealed by simultaneous measurement of tension and stiffness.

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Kobayashi, Masahiko; Takemori, Shigeru; Yamaguchi, Maki

2004-02-10

Based on the molecular mechanism of rigor mortis, we have proposed that stiffness (elastic modulus evaluated with tension response against minute length perturbations) can be a suitable index of post-mortem rigidity in skeletal muscle. To trace the developmental process of rigor mortis, we measured stiffness and tension in both red and white rat skeletal muscle kept in liquid paraffin at 37 and 25 degrees C. White muscle (in which type IIB fibres predominate) developed stiffness and tension significantly more slowly than red muscle, except for soleus red muscle at 25 degrees C, which showed disproportionately slow rigor development. In each of the examined muscles, stiffness and tension developed more slowly at 25 degrees C than at 37 degrees C. In each specimen, tension always reached its maximum level earlier than stiffness, and then decreased more rapidly and markedly than stiffness. These phenomena may account for the sequential progress of rigor mortis in human cadavers.

Fetal development of deep back muscles in the human thoracic region with a focus on transversospinalis muscles and the medial branch of the spinal nerve posterior ramus

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Sato, Tatsuo; Koizumi, Masahiro; Kim, Ji Hyun; Kim, Jeong Hyun; Wang, Bao Jian; Murakami, Gen; Cho, Baik Hwan

2011-01-01

Fetal development of human deep back muscles has not yet been fully described, possibly because of the difficulty in identifying muscle bundle directions in horizontal sections. Here, we prepared near-frontal sections along the thoracic back skin (eight fetuses) as well as horizontal sections (six fetuses) from 14 mid-term fetuses at 9–15 weeks of gestation. In the deep side of the trapezius and rhomboideus muscles, the CD34-positive thoracolumbar fascia was evident even at 9 weeks. Desmin-reactivity was strong and homogeneous in the superficial muscle fibers in contrast to the spotty expression in the deep fibers. Thus, in back muscles, formation of the myotendinous junction may start from the superficial muscles and advance to the deep muscles. The fact that developing intramuscular tendons were desmin-negative suggested little possibility of a secondary change from the muscle fibers to tendons. We found no prospective spinalis muscle or its tendinous connections with other muscles. Instead, abundant CD68-positive macrophages along the spinous process at 15 weeks suggested a change in muscle attachment, an event that may result in a later formation of the spinalis muscle. S100-positive intramuscular nerves exhibited downward courses from the multifidus longus muscle in the original segment to the rotatores brevis muscles in the inferiorly adjacent level. The medial cutaneous nerve had already reached the thoracolumbar fascia at 9 weeks, but by 15 weeks the nerve could not penetrate the trapezius muscle. Finally, we propose a folded myotomal model of the primitive transversospinalis muscle that seems to explain a fact that the roofing tile-like configuration of nerve twigs in the semispinalis muscle is reversed in the multifidus and rotatores muscles. PMID:21954879

New twist on artificial muscles.

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Haines, Carter S; Li, Na; Spinks, Geoffrey M; Aliev, Ali E; Di, Jiangtao; Baughman, Ray H

2016-10-18

Lightweight artificial muscle fibers that can match the large tensile stroke of natural muscles have been elusive. In particular, low stroke, limited cycle life, and inefficient energy conversion have combined with high cost and hysteretic performance to restrict practical use. In recent years, a new class of artificial muscles, based on highly twisted fibers, has emerged that can deliver more than 2,000 J/kg of specific work during muscle contraction, compared with just 40 J/kg for natural muscle. Thermally actuated muscles made from ordinary polymer fibers can deliver long-life, hysteresis-free tensile strokes of more than 30% and torsional actuation capable of spinning a paddle at speeds of more than 100,000 rpm. In this perspective, we explore the mechanisms and potential applications of present twisted fiber muscles and the future opportunities and challenges for developing twisted muscles having improved cycle rates, efficiencies, and functionality. We also demonstrate artificial muscle sewing threads and textiles and coiled structures that exhibit nearly unlimited actuation strokes. In addition to robotics and prosthetics, future applications include smart textiles that change breathability in response to temperature and moisture and window shutters that automatically open and close to conserve energy.

Muscle Stem Cell Therapy for the Treatment of DMD Associated Cardiomyopathy

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2013-10-01

SUBTITLE Muscle Stem Cell Therapy for the Treatment of DMD Associated Cardiomyopathy 5a. CONTRACT NUMBER Subproject 1: Muscle Stem Cell Therapy...various muscle diseases, including Duchenne muscular dystrophy (DMD), develop progressive cardiomyopathy. Cellular cardiomyoplasty, which involves the

Development of artificial muscles based on electroactive ionomeric polymer-metal composites.

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Hirano, Laos A; Escote, Márcia T; Martins-Filho, Luiz S; Mantovani, Gerson L; Scuracchio, Carlos H

2011-05-01

This work contextualizes the research of materials that can be applied as artificial muscles. The main motivation of this research is the importance of the development of mechatronic systems for the replacement of traditional devices of actuation and motion based on rotational electrical motors by other devices that reproduce biological muscle movements. Electroactive polymers (EAPs) are materials that respond to electric stimuli with shape and/or dimension changes, and accomplish movements that are smooth enough to mimic biological muscles. Among EAPs, the ionomeric polymer-metal composites (IPMCs) are an interesting alternative to biomimetic devices due to large displacements when submitted to low applied voltage. This article presents a brief review of IPMCs, a sample preparation procedure, and some electromechanical experimental results. We also discuss the applicability of this technology in medical devices and as artificial muscles. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Mediators on human airway smooth muscle.

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Armour, C; Johnson, P; Anticevich, S; Ammit, A; McKay, K; Hughes, M; Black, J

1997-01-01

1. Bronchial hyperresponsiveness in asthma may be due to several abnormalities, but must include alterations in the airway smooth muscle responsiveness and/or volume. 2. Increased responsiveness of airway smooth muscle in vitro can be induced by certain inflammatory cell products and by induction of sensitization (atopy). 3. Increased airway smooth muscle growth can also be induced by inflammatory cell products and atopic serum. 4. Mast cell numbers are increased in the airways of asthmatics and, in our studies, in airway smooth muscle that is sensitized and hyperresponsive. 5. We propose that there is a relationship between mast cells and airway smooth muscle cells which, once an allergic process has been initiated, results in the development of critical features in the lungs in asthma.

Hydraulically actuated artificial muscles

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Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.

2012-04-01

Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

ELECTRICAL MUSCLE STIMULATION (EMS IMPLEMENTATION IN EXPLOSIVE STRENGTH DEVELOPMENT

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Zoran Đokić

2013-07-01

Full Text Available Electrical muscle stimulation (EMS, is also known as neuromuscular electrical stimulation (NMES may be used for therapeutic purposes and training. EMS is causing muscle contractions via electrical impulses. The survey was conducted as a case study. The study was conducted on subject of 3 male of different ages. The study lasted 4 weeks, and the respondents have not used any type of training or activity, which would affect the development of explosive strength of the lower extremities. Electrical stimulation was performed in the evening, every other day, with COMPEX mi sport apparatus (Medical SA - All rights reserved - 07/06 - Art. 885,616 - V.2 model. In 4 week period, a total of 13 treatments were performed on selected muscle groups - quadriceps femoris and gastrocnemius. Program of plyometric training (Plyometric (28 min per treatment, for each muscle group were applied. The main objective of this study was to quantify and compare explosive leg strength, using different vertical jump protocols, before and after the EMS program. The initial and final testing was conducted in the laboratory of the Faculty of Sport and Tourism in Novi Sad, on the contact plate AXON JUMP (Bioingeniería Deportiva, VACUMED, 4538 Westinghouse Street Ventura, CA 93 003 under identical conditions. In all three of the respondents indicated an increase in vertical jump in all applied protocols.

Thermal Manipulation Mid-term Broiler Chicken Embryogenesis: Effect on Muscle Growth Factors and Muscle Marker Genes

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MB Al-Zghoul

Full Text Available ABSTRACT Thermal manipulation (TM during broiler chicken embryogenesis has been shown to promote muscle development and growth. However, the molecular bases of promoting broiler muscle development and growth are not fully understood. The aim of this study was to investigate the molecular bases of muscle growth and development in broiler chickens subjected to TM. This included the investigating of the changes in mRNA expression levels of muscle marker genes, namely MyoD, myogenin, paired box transcription factor (Pax7 and proliferating cell nuclear antigen (PCNA, and muscle growth factors namely insulin-like growth factor 1 (IGF-1, myostatin and growth hormone (GH during embryogenesis and on posthatch days 10 and 28. Fertile Cobb eggs (n=1500 were divided into four groups. Eggs in the first group (control were incubated at 37.8°C and 56% RH, whereas, eggs in the second group (TM1, third group (TM2, and fourth group (TM3 were subjected to 39 ºC and 65% RH daily during embryonic days (ED 12-18 for 9, 12, and 18 hours, respectively. Body weight (BW during embryogenesis and posthatch days (1, 3, 5, 7, 14, 21, 28 and 35 was recorded. mRNA expression levels of muscle marker genes and muscle growth factor genes during ED 12, 14, 16 and 18 and on posthatch days 10 and 28 were analyzed using real-time RT-PCR. TM upregulated the mRNA expressions of muscle marker and growth factors genes. This upregulation was accompanied by improvement of body weight near and at market age.

The number and choice of muscles impact the results of muscle synergy analyses

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Katherine Muterspaugh Steele

2013-08-01

Full Text Available One theory for how humans control movement is that muscles are activated in weighted groups or synergies. Studies have shown that electromyography (EMG from a variety of tasks can be described by a low-dimensional space thought to reflect synergies. These studies use algorithms, such as nonnegative matrix factorization, to identify synergies from EMG. Due to experimental constraints, EMG can rarely be taken from all muscles involved in a task. However, it is unclear if the choice of muscles included in the analysis impacts estimated synergies. The aim of our study was to evaluate the impact of the number and choice of muscles on synergy analyses. We used a musculoskeletal model to calculate muscle activations required to perform an isometric upper-extremity task. Synergies calculated from the activations from the musculoskeletal model were similar to a prior experimental study. To evaluate the impact of the number of muscles included in the analysis, we randomly selected subsets of between 5 and 29 muscles and compared the similarity of the synergies calculated from each subset to a master set of synergies calculated from all muscles. We determined that the structure of synergies is dependent upon the number and choice of muscles included in the analysis. When five muscles were included in the analysis, the similarity of the synergies to the master set was only 0.57 ± 0.54; however, the similarity improved to over 0.8 with more than ten muscles. We identified two methods, selecting dominant muscles from the master set or selecting muscles with the largest maximum isometric force, which significantly improved similarity to the master set and can help guide future experimental design. Analyses that included a small subset of muscles also over-estimated the variance accounted for (VAF by the synergies compared to an analysis with all muscles. Thus, researchers should use caution using VAF to evaluate synergies when EMG is measured from a small

Patterns of spatial and temporal visceral arch muscle development in the Mexican axolotl (Ambystoma mexicanum).

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Ericsson, Rolf; Olsson, Lennart

2004-08-01

Vertebrate head development is a classical topic that has received renewed attention during the last decade. Most reports use one of a few model organisms (chicken, mouse, zebrafish) and have focused on molecular mechanisms and the role of the neural crest, while cranial muscle development has received less attention. Here we describe cranial muscle differentiation and morphogenesis in the Mexican axolotl, Ambystoma mexicanum. To determine the onset of differentiation we use antibodies against desmin and optical sectioning using confocal laser scanning microscopy on whole-mount immunostained embryos. This technique makes it possible to document the cranial muscle in three dimensions while keeping the specimens intact. Desmin expression starts almost simultaneously in the first, second, and third visceral arch muscles (as in other amphibians studied). Muscle anlagen divide up early into the different elements which constitute the larval cranial musculature. We extend and refine earlier findings, e.g., by documenting a clear division between interhyoideus and interhyoideus posterior. The timing of cranial muscle differentiation differs among vertebrate groups, but seems to be constant within each group. This study provides a morphological foundation for further studies of muscle cell fate and early differentiation. Copyright 2004 Wiley-Liss, Inc.

The Development of a Flexible Measuring System for Muscle Volume Using Ultrasonography

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Fukumoto, Kiyotaka; Fukuda, Osamu; Tsubai, Masayoshi; Muraki, Satoshi

Quantification of muscle volume can be used as a means for the estimation of muscle strength. Its measuring process does not need the subject's muscular contractions so it is completely safe and particularly suited for elderly people. Therefore, we have developed a flexible measuring system for muscle volume using ultrasonography. In this system, an ultrasound probe is installed on a link mechanism which continuously scans fragmental images along the human body surface. These images are then measured and composed into a wide area cross-sectional image based on the spatial compounding method. The flexibility of the link mechanism enables the operator to measure the images under any body postures and body site. The spatial compounding method significantly reduces speckle and artifact noises from the composed cross-sectional image so that the operator can observe the individual muscles, such as Rectus femoris, Vastus intermedius, and so on, in detail. We conducted the experiments in order to examine the advantages of this system we have developed. The experimental results showed a high accuracy of the measuring position which was calculated using the link mechanism and presented the noise reduction effect based on the spatial compounding method. Finally, we confirmed high correlations between the MRI images and the ones of the developed system to verify the validity of the system.

Muscle layer histopathology and manometry pattern of primary esophageal motility disorders including achalasia.

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Nakajima, N; Sato, H; Takahashi, K; Hasegawa, G; Mizuno, K; Hashimoto, S; Sato, Y; Terai, S

2017-03-01

Histopathology of muscularis externa in primary esophageal motility disorders has been characterized previously. We aimed to correlate the results of high-resolution manometry with those of histopathology. During peroral endoscopic myotomy, peroral esophageal muscle biopsy was performed in patients with primary esophageal motility disorders. Immunohistochemical staining for c-kit was performed to assess the interstitial cells of Cajal (ICCs). Hematoxylin Eosin and Azan-Mallory staining were used to detect muscle atrophy, inflammation, and fibrosis, respectively. Slides from 30 patients with the following motility disorders were analyzed: achalasia (type I: 14, type II: 5, type III: 3), one diffuse esophageal spasm (DES), two outflow obstruction (OO), four jackhammer esophagus (JE), and one nutcracker esophagus (NE). ICCs were preserved in high numbers in type III achalasia (n=9.4±1.2 cells/high power field [HPF]), compared to types I (n=3.7±0.3 cells/HPF) and II (n=3.5±1.0 cells/HPF). Moreover, severe fibrosis was only observed in type I achalasia and not in other types of achalasia, OO, or DES. Four of five patients with JE and NE had severe inflammation with eosinophilic infiltration of the esophageal muscle layer (73.8±50.3 eosinophils/HPF) with no epithelial eosinophils. One patient with JE showed a visceral myopathy pattern. Compared to types I and II, type III achalasia showed preserved ICCs, with variable data regarding DES and OO. In disorders considered as primary esophageal motility disorders, a disease category exists, which shows eosinophilic infiltration in the esophageal muscle layer with no eosinophils in the epithelium. © 2016 John Wiley & Sons Ltd.

STIM1 as a key regulator for Ca2+ homeostasis in skeletal-muscle development and function

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Kiviluoto Santeri

2011-04-01

enhanced Ca2+ influx through Orai1 and/or TRPC channels, leading to Ca2+-dependent apoptosis and muscle degeneration. In addition, human myopathies have been associated with dysfunctional SOCE. Immunodeficient patients harboring loss-of-function Orai1 mutations develop myopathies, while patients suffering from Duchenne muscular dystrophy display alterations in their Ca2+-handling proteins, including STIM proteins. In any case, the molecular determinants responsible for SOCE in human skeletal muscle and for dysregulated SOCE in patients of muscular dystrophy require further examination.

Diversification of intrinsic motoneuron electrical properties during normal development and botulinum toxin-induced muscle paralysis in early postnatal mice.

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Nakanishi, S T; Whelan, P J

2010-05-01

During early postnatal development, between birth and postnatal days 8-11, mice start to achieve weight-bearing locomotion. In association with the progression of weight-bearing locomotion there are presumed developmental changes in the intrinsic electrical properties of spinal -motoneurons. However, these developmental changes in the properties of -motoneuron properties have not been systematically explored in mice. Here, data are presented documenting the developmental changes of selected intrinsic motoneuron electrical properties, including statistically significant changes in action potential half-width, intrinsic excitability and diversity (quantified as coefficient of variation) of rheobase current, afterhyperpolarization half-decay time, and input resistance. In various adult mammalian preparations, the maintenance of intrinsic motoneuron electrical properties is dependent on activity and/or transmission-sensitive motoneuron-muscle interactions. In this study, we show that botulinum toxin-induced muscle paralysis led to statistically significant changes in the normal development of intrinsic motoneuron electrical properties in the postnatal mouse. This suggests that muscle activity during early neonatal life contributes to the development of normal motoneuron electrical properties.

Pneumatic Artificial Muscles Based on Biomechanical Characteristics of Human Muscles

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N. Saga

2006-01-01

Full Text Available This article reports the pneumatic artificial muscles based on biomechanical characteristics of human muscles. A wearable device and a rehabilitation robot that assist a human muscle should have characteristics similar to those of human muscle. In addition, since the wearable device and the rehabilitation robot should be light, an actuator with a high power to weight ratio is needed. At present, the McKibben type is widely used as an artificial muscle, but in fact its physical model is highly nonlinear. Therefore, an artificial muscle actuator has been developed in which high-strength carbon fibres have been built into the silicone tube. However, its contraction rate is smaller than the actual biological muscles. On the other hand, if an artificial muscle that contracts axially is installed in a robot as compactly as the robot hand, big installing space is required. Therefore, an artificial muscle with a high contraction rate and a tendon-driven system as a compact actuator were developed, respectively. In this study, we report on the basic structure and basic characteristics of two types of actuators.

Muscle Attenuation Is Associated With Newly Developed Hypertension in Men of African Ancestry.

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Zhao, Qian; Zmuda, Joseph M; Kuipers, Allison L; Bunker, Clareann H; Patrick, Alan L; Youk, Ada O; Miljkovic, Iva

2017-05-01

Increased ectopic adipose tissue infiltration in skeletal muscle is associated with insulin resistance and diabetes mellitus. We evaluated whether change in skeletal muscle adiposity predicts subsequent development of hypertension in men of African ancestry, a population sample understudied in previous studies. In the Tobago Health Study, a prospective longitudinal study among men of African ancestry (age range 40-91 years), calf intermuscular adipose tissue, and skeletal muscle attenuation were measured with computed tomography. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, or a diastolic blood pressure ≥90 mm Hg, or receiving antihypertensive medications. Logistic regression was performed with adjustment for age, insulin resistance, baseline and 6-year change in body mass index, baseline and 6-year change in waist circumference, and other potential confounding factors. Among 746 normotensive men at baseline, 321 (43%) developed hypertension during the mean 6.2 years of follow-up. Decreased skeletal muscle attenuation was associated with newly developed hypertension after adjustment for baseline and 6-year change of body mass index (odds ratio [95% confidence interval] per SD, 1.3 [1.0-1.6]) or baseline and 6-year change of waist circumference (odds ratio [95% confidence interval] per SD, 1.3 [1.0-1.6]). No association was observed between increased intermuscular adipose tissue and hypertension. Our novel findings show that decreased muscle attenuation is associated with newly developed hypertension among men of African ancestry, independent of general and central adiposity and insulin resistance. Further studies are needed to adjust for inflammation, visceral and other ectopic adipose tissue depots, and to confirm our findings in other population samples. © 2017 American Heart Association, Inc.

Identification of Histone Deacetylase 2 as a Functional Gene for Skeletal Muscle Development in Chickens

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Md. Shahjahan

2016-04-01

Full Text Available A previous genome-wide association study (GWAS exposed histone deacetylase 2 (HDAC2 as a possible candidate gene for breast muscle weight in chickens. The present research has examined the possible role of HDAC2 in skeletal muscle development in chickens. Gene expression was measured by quantitative polymerase chain reaction in breast and thigh muscles during both embryonic (four ages and post-hatch (five ages development and in cultures of primary myoblasts during both proliferation and differentiation. The expression of HDAC2 increased significantly across embryonic days (ED in breast (ED 14, 16, 18, and 21 and thigh (ED 14 and 18, and ED 14 and 21 muscles suggesting that it possibly plays a role in myoblast hyperplasia in both breast and thigh muscles. Transcript abundance of HDAC2 identified significantly higher in fast growing muscle than slow growing in chickens at d 90 of age. Expression of HDAC2 during myoblast proliferation in vitro declined between 24 h and 48 h when expression of the marker gene paired box 7 (PAX7 increased and cell numbers increased throughout 72 h of culture. During induced differentiation of myoblasts to myotubes, the abundance of HDAC2 and the marker gene myogenic differentiation 1 (MYOD1, both increased significantly. Taken together, it is suggested that HDAC2 is most likely involved in a suppressive fashion in myoblast proliferation and may play a positive role in myoblast differentiation. The present results confirm the suggestion that HDAC2 is a functional gene for pre-hatch and post-hatch (fast growing muscle development of chicken skeletal muscle.

Skeletal muscle and fetal alcohol spectrum disorder.

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Myrie, Semone B; Pinder, Mark A

2018-04-01

Skeletal muscle is critical for mobility and many metabolic functions integral to survival and long-term health. Alcohol can affect skeletal muscle physiology and metabolism, which will have immediate and long-term consequences on health. While skeletal muscle abnormalities, including morphological, biochemical, and functional impairments, are well-documented in adults that excessively consume alcohol, there is a scarcity of information about the skeletal muscle in the offspring prenatally exposed to alcohol ("prenatal alcohol exposure"; PAE). This minireview examines the available studies addressing skeletal muscle abnormalities due to PAE. Growth restriction, fetal alcohol myopathy, and abnormalities in the neuromuscular system, which contribute to deficits in locomotion, are some direct, immediate consequences of PAE on skeletal muscle morphology and function. Long-term health consequences of PAE-related skeletal abnormalities include impaired glucose metabolism in the skeletal muscle, resulting in glucose intolerance and insulin resistance, leading to an increased risk of type 2 diabetes. In general, there is limited information on the morphological, biochemical, and functional features of skeletal abnormalities in PAE offspring. There is a need to understand how PAE affects muscle growth and function at the cellular level during early development to improve the immediate and long-term health of offspring suffering from PAE.

Development of a subset of forelimb muscles and their attachment sites requires the ulnar-mammary syndrome gene Tbx3

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Mary P. Colasanto

2016-11-01

Full Text Available In the vertebrate limb over 40 muscles are arranged in a precise pattern of attachment via muscle connective tissue and tendon to bone and provide an extensive range of motion. How the development of somite-derived muscle is coordinated with the development of lateral plate-derived muscle connective tissue, tendon and bone to assemble a functional limb musculoskeletal system is a long-standing question. Mutations in the T-box transcription factor, TBX3, have previously been identified as the genetic cause of ulnar-mammary syndrome (UMS, characterized by distinctive defects in posterior forelimb bones. Using conditional mutagenesis in mice, we now show that TBX3 has a broader role in limb musculoskeletal development. TBX3 is not only required for development of posterior forelimb bones (ulna and digits 4 and 5, but also for a subset of posterior muscles (lateral triceps and brachialis and their bone eminence attachment sites. TBX3 specification of origin and insertion sites appears to be tightly linked with whether these particular muscles develop and may represent a newly discovered mechanism for specification of anatomical muscles. Re-examination of an individual with UMS reveals similar previously unrecognized muscle and bone eminence defects and indicates a conserved role for TBX3 in regulating musculoskeletal development.

The microRNA, miR-29c, participates in muscle development through targeting the YY1 gene and is associated with postmortem muscle pH in pigs

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Weiya ZHANG,Wei WEI,Yuanyuan ZHAO,Shuhong ZHAO,Xinyun LI

2015-12-01

Full Text Available Previous studies indicated that miR-29c is important for muscle development in mice and human, but its role in pigs is unknown. In this study, we detected the expression of miR-29c in Meishan longissimus lumborum (LL muscle. The results showed that miR-29c was gradually upregulated during development of skeletal muscle in pig. Moreover, the expression of YY1 and Akt3 genes, which were confirmed to be targeted by miR-29c in mice, was decreased along with muscle development. Furthermore, the expression level of miR-29c was significantly higher in adult Meishan pigs than Large White pigs, while the expression of YY1 and Akt3 genes was significantly lower in Meishan pigs. These results indicated that the expression pattern of miR-29c was opposite to that of YY1 and Akt3 genes in pigs. Also, the luciferase assay indicated that miR-29s can target the YY1 gene in pigs. In addition, we identified a T to C mutation in the primary transcript of miR-29c, which was associated with the postmortem muscle pH in pigs. Based on these results, we concluded that miR-29c is also important in skeletal muscle development of pigs.

Study of muscle cell dedifferentiation after skeletal muscle injury of mice with a Cre-Lox system.

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Mu, Xiaodong; Peng, Hairong; Pan, Haiying; Huard, Johnny; Li, Yong

2011-02-03

Dedifferentiation of muscle cells in the tissue of mammals has yet to be observed. One of the challenges facing the study of skeletal muscle cell dedifferentiation is the availability of a reliable model that can confidentially distinguish differentiated cell populations of myotubes and non-fused mononuclear cells, including stem cells that can coexist within the population of cells being studied. In the current study, we created a Cre/Lox-β-galactosidase system, which can specifically tag differentiated multinuclear myotubes and myotube-generated mononuclear cells based on the activation of the marker gene, β-galactosidase. By using this system in an adult mouse model, we found that β-galactosidase positive mononuclear cells were generated from β-galactosidase positive multinuclear myofibers upon muscle injury. We also demonstrated that these mononuclear cells can develop into a variety of different muscle cell lineages, i.e., myoblasts, satellite cells, and muscle derived stem cells. These novel findings demonstrated, for the first time, that cellular dedifferentiation of skeletal muscle cells actually occurs in mammalian skeletal muscle following traumatic injury in vivo.

Dynamic contraction behaviour of pneumatic artificial muscle

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Doumit, Marc D.; Pardoel, Scott

2017-07-01

The development of a dynamic model for the Pneumatic Artificial Muscle (PAM) is an imperative undertaking for understanding and analyzing the behaviour of the PAM as a function of time. This paper proposes a Newtonian based dynamic PAM model that includes the modeling of the muscle geometry, force, inertia, fluid dynamic, static and dynamic friction, heat transfer and valve flow while ignoring the effect of bladder elasticity. This modeling contribution allows the designer to predict, analyze and optimize PAM performance prior to its development. Thus advancing successful implementations of PAM based powered exoskeletons and medical systems. To date, most muscle dynamic properties are determined experimentally, furthermore, no analytical models that can accurately predict the muscle's dynamic behaviour are found in the literature. Most developed analytical models adequately predict the muscle force in static cases but neglect the behaviour of the system in the transient response. This could be attributed to the highly challenging task of deriving such a dynamic model given the number of system elements that need to be identified and the system's highly non-linear properties. The proposed dynamic model in this paper is successfully simulated through MATLAB programing and validated the pressure, contraction distance and muscle temperature with experimental testing that is conducted with in-house built prototype PAM's.

Aberrant repair and fibrosis development in skeletal muscle

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Mann Christopher J

2011-05-01

Full Text Available Abstract The repair process of damaged tissue involves the coordinated activities of several cell types in response to local and systemic signals. Following acute tissue injury, infiltrating inflammatory cells and resident stem cells orchestrate their activities to restore tissue homeostasis. However, during chronic tissue damage, such as in muscular dystrophies, the inflammatory-cell infiltration and fibroblast activation persists, while the reparative capacity of stem cells (satellite cells is attenuated. Abnormal dystrophic muscle repair and its end stage, fibrosis, represent the final common pathway of virtually all chronic neurodegenerative muscular diseases. As our understanding of the pathogenesis of muscle fibrosis has progressed, it has become evident that the muscle provides a useful model for the regulation of tissue repair by the local microenvironment, showing interplay among muscle-specific stem cells, inflammatory cells, fibroblasts and extracellular matrix components of the mammalian wound-healing response. This article reviews the emerging findings of the mechanisms that underlie normal versus aberrant muscle-tissue repair.

A gene network switch enhances the oxidative capacity of ovine skeletal muscle during late fetal development

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Bidwell Christopher A

2010-06-01

Full Text Available Abstract Background The developmental transition between the late fetus and a newborn animal is associated with profound changes in skeletal muscle function as it adapts to the new physiological demands of locomotion and postural support against gravity. The mechanisms underpinning this adaption process are unclear but are likely to be initiated by changes in hormone levels. We tested the hypothesis that this developmental transition is associated with large coordinated changes in the transcription of skeletal muscle genes. Results Using an ovine model, transcriptional profiling was performed on Longissimus dorsi skeletal muscle taken at three fetal developmental time points (80, 100 and 120 d of fetal development and two postnatal time points, one approximately 3 days postpartum and a second at 3 months of age. The developmental time course was dominated by large changes in expression of 2,471 genes during the interval between late fetal development (120 d fetal development and 1-3 days postpartum. Analysis of the functions of genes that were uniquely up-regulated in this interval showed strong enrichment for oxidative metabolism and the tricarboxylic acid cycle indicating enhanced mitochondrial activity. Histological examination of tissues from these developmental time points directly confirmed a marked increase in mitochondrial activity between the late fetal and early postnatal samples. The promoters of genes that were up-regulated during this fetal to neonatal transition were enriched for estrogen receptor 1 and estrogen related receptor alpha cis-regulatory motifs. The genes down-regulated during this interval highlighted de-emphasis of an array of functions including Wnt signaling, cell adhesion and differentiation. There were also changes in gene expression prior to this late fetal - postnatal transition and between the two postnatal time points. The former genes were enriched for functions involving the extracellular matrix and immune

Identification and profiling of microRNAs and their target genes from developing caprine skeletal Muscle.

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Yanhong Wang

Full Text Available Goat is an important agricultural animal for meat production. Functional studies have demonstrated that microRNAs (miRNAs regulate gene expression at the post-transcriptional level and play an important role in various biological processes. Although studies on miRNAs expression profiles have been performed in various animals, relatively limited information about goat muscle miRNAs has been reported. To investigate the miRNAs involved in regulating different periods of skeletal muscle development, we herein performed a comprehensive research for expression profiles of caprine miRNAs during two developmental stages of skeletal muscles: fetal stage and six month-old stage. As a result, 15,627,457 and 15,593,721 clean reads were obtained from the fetal goat library (FC and the six month old goat library (SMC, respectively. 464 known miRNAs and 83 novel miRNA candidates were identified. Furthermore, by comparing the miRNA profile, 336 differentially expressed miRNAs were identified and then the potential targets of the differentially expressed miRNAs were predicted. To understand the regulatory network of miRNAs during muscle development, the mRNA expression profiles for the two development stages were characterized and 7322 differentially expressed genes (DEGs were identified. Then the potential targets of miRNAs were compared to the DEGs, the intersection of the two gene sets were screened out and called differentially expressed targets (DE-targets, which were involved in 231 pathways. Ten of the 231 pathways that have smallest P-value were shown as network figures. Based on the analysis of pathways and networks, we found that miR-424-5p and miR-29a might have important regulatory effect on muscle development, which needed to be further studied. This study provided the first global view of the miRNAs in caprine muscle tissues. Our results help elucidation of complex regulatory networks between miRNAs and mRNAs and for the study of muscle

An α-smooth muscle actin (acta2/αsma zebrafish transgenic line marking vascular mural cells and visceral smooth muscle cells.

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Thomas R Whitesell

Full Text Available Mural cells of the vascular system include vascular smooth muscle cells (SMCs and pericytes whose role is to stabilize and/or provide contractility to blood vessels. One of the earliest markers of mural cell development in vertebrates is α smooth muscle actin (acta2; αsma, which is expressed by pericytes and SMCs. In vivo models of vascular mural cell development in zebrafish are currently lacking, therefore we developed two transgenic zebrafish lines driving expression of GFP or mCherry in acta2-expressing cells. These transgenic fish were used to trace the live development of mural cells in embryonic and larval transgenic zebrafish. acta2:EGFP transgenic animals show expression that largely mirrors native acta2 expression, with early pan-muscle expression starting at 24 hpf in the heart muscle, followed by skeletal and visceral muscle. At 3.5 dpf, expression in the bulbus arteriosus and ventral aorta marks the first expression in vascular smooth muscle. Over the next 10 days of development, the number of acta2:EGFP positive cells and the number of types of blood vessels associated with mural cells increases. Interestingly, the mural cells are not motile and remain in the same position once they express the acta2:EGFP transgene. Taken together, our data suggests that zebrafish mural cells develop relatively late, and have little mobility once they associate with vessels.

Quantitative phosphoproteomic analysis of porcine muscle within 24 h postmortem

DEFF Research Database (Denmark)

Huang, Honggang; Larsen, Martin Røssel; Palmisano, Giuseppe

2014-01-01

in meat quality development, a quantitative mass spectrometry-based phosphoproteomic study was performed to analyze the porcine muscle within 24h PM using dimethyl labeling combined with the TiSH phosphopeptide enrichment strategy. In total 305 unique proteins were identified, including 160...... phosphorylation levels in muscle within 24 h PM. The high phosphorylation level of heat shock proteins (HSPs) in early PM may be an adaptive response to slaughter stress and protect muscle cell from apoptosis, as observed in the serine 84 of HSP27. This work indicated that PM muscle proteins underwent significant...... and rigor mortis development in PM muscle. BIOLOGICAL SIGNIFICANCE: The manuscript describes the characterization of postmortem (PM) porcine muscle within 24 h postmortem from the perspective of protein phosphorylation using advanced phosphoproteomic techniques. In the study, the authors employed...

Development of rigor mortis is not affected by muscle volume.

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Kobayashi, M; Ikegaya, H; Takase, I; Hatanaka, K; Sakurada, K; Iwase, H

2001-04-01

There is a hypothesis suggesting that rigor mortis progresses more rapidly in small muscles than in large muscles. We measured rigor mortis as tension determined isometrically in rat musculus erector spinae that had been cut into muscle bundles of various volumes. The muscle volume did not influence either the progress or the resolution of rigor mortis, which contradicts the hypothesis. Differences in pre-rigor load on the muscles influenced the onset and resolution of rigor mortis in a few pairs of samples, but did not influence the time taken for rigor mortis to reach its full extent after death. Moreover, the progress of rigor mortis in this muscle was biphasic; this may reflect the early rigor of red muscle fibres and the late rigor of white muscle fibres.

Primary sacrococcygeal chordoma with unusual skeletal muscle metastasis

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Lisa Vu, MD

2014-01-01

Full Text Available Chordomas are rare neoplasms that do not often metastasize. Of the small percent that do metastasize, they very infrequently involve skeletal muscle. Only a few cases of skeletal muscle metastases have been reported in the literature. We report an unusual case of a patient with a primary sacrococcygeal chordoma who experienced a long period of remission but who subsequently developed recurrence and multiple metastatic lesions to skeletal muscles including the deltoid, triceps, and pectineus.

Flight Muscle Development in the Males of Glossina Pallidipes Reared for the Sterile Insect Technique

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Ciampor, F Jr; Palosova, Z; Mancosova, L; Takac, P [Institute of Zoology, Slovak Academy of Sciences, Bratislava, SK-845 06 (Slovakia)

2012-07-15

The project's main goal was to study the influence of laboratory conditions on the development of flight muscles and the ability to fly in males of Glossina pallidipes Austen. Flight muscles can serve as an important criterion in the quality control of mass reared tsetse flies. All experiments were performed in the research and training facility in Bratislava which provided the flies. The experiments were generally performed by comparing different age groups and groups with different flight activity. To acquire data, several approaches were employed, i.e. classical measurements (residual dry weight, thoracic surface) as well as other alternatives - flight mill, electron microscopy and immunohistochemistry - to visualize and analyse muscle development. The results clearly identified differences in age groups. Slight changes in the development of flight muscles regarding different chances to fly were also detected, but these were not sufficiently significant to decrease the quality of males produced in mass rearing facilities. No distinct trends (rising or declining of amount of metabolites) in the groups studied were detected. The differences were in the amount of analysed metabolic components and the structure of the flight muscles. Our results suggest that, similar to other Glossina species, in G. pallidipes males the first days after emergence are crucial for successful muscle development. On the other hand, rearing in cages does not negatively influence the quality of males with respect to their ability to fly and actively search for females in the wild after release. We also compared the mating behaviour of irradiated and non-irradiated males. We initiated the development of a functional walk-in field cage in which to rear a small colony of G. pallidipes under semi-natural conditions. Our work suggested that outside climatic conditions and suitable cage components, e.g. food source, limit the successful realization of using such a cage for rearing tsetse flies

Development of mapped stress-field boundary conditions based on a Hill-type muscle model.

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Cardiff, P; Karač, A; FitzPatrick, D; Flavin, R; Ivanković, A

2014-09-01

Forces generated in the muscles and tendons actuate the movement of the skeleton. Accurate estimation and application of these musculotendon forces in a continuum model is not a trivial matter. Frequently, musculotendon attachments are approximated as point forces; however, accurate estimation of local mechanics requires a more realistic application of musculotendon forces. This paper describes the development of mapped Hill-type muscle models as boundary conditions for a finite volume model of the hip joint, where the calculated muscle fibres map continuously between attachment sites. The applied muscle forces are calculated using active Hill-type models, where input electromyography signals are determined from gait analysis. Realistic muscle attachment sites are determined directly from tomography images. The mapped muscle boundary conditions, implemented in a finite volume structural OpenFOAM (ESI-OpenCFD, Bracknell, UK) solver, are employed to simulate the mid-stance phase of gait using a patient-specific natural hip joint, and a comparison is performed with the standard point load muscle approach. It is concluded that physiological joint loading is not accurately represented by simplistic muscle point loading conditions; however, when contact pressures are of sole interest, simplifying assumptions with regard to muscular forces may be valid. Copyright © 2014 John Wiley & Sons, Ltd.

Development of a linear induction motor based artificial muscle system.

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Gruber, A; Arguello, E; Silva, R

2013-01-01

We present the design of a linear induction motor based on electromagnetic interactions. The engine is capable of producing a linear movement from electricity. The design consists of stators arranged in parallel, which produce a magnetic field sufficient to displace a plunger along its axial axis. Furthermore, the winding has a shell and cap of ferromagnetic material that amplifies the magnetic field. This produces a force along the length of the motor that is similar to that of skeletal muscle. In principle, the objective is to use the engine in the development of an artificial muscle system for prosthetic applications, but it could have multiple applications, not only in the medical field, but in other industries.

Cell death induced by gamma irradiation of developing skeletal muscle

International Nuclear Information System (INIS)

Olive, M.; Blanco, R.; Rivera, R.; Cinos, C.; Ferrer, I.

1995-01-01

Newborn Sprague-Dawley rats were exposed to a single dose of 2 Gy gamma rays and killed from 6 h to 5 d later. Increased numbers of dying cells, characterised by their extreme chromatin condensation and often nuclear fragmentation were seen in skeletal muscle 6 h after irradiation. Dying cells decreased to nearly normal values 48 h later. In situ labelling of nuclear DNA fragmentation identified individual cells bearing fragmented DNA. The effects of gamma rays were suppressed following cycloheximide i.p. at a dose of 1 μg/g body weight given at the time of irradiation. Taken together, the present morphological and pharmacological results suggest that gamma ray induced cell death in skeletal muscle is apoptotic, and that the process is associated with protein synthesis. Finally, proliferating cell nuclear antigen-immunoreactive cells, which were abundant in control rats, decreased in number 48 h after irradiation. However, a marked increase significantly above normal age values was observed at the 5th day, thus suggesting that regeneration occurs following irradiation-induced cell death in developing muscle. (author)

A Phenomenological Model and Validation of Shortening Induced Force Depression during Muscle Contractions

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McGowan, C.P.; Neptune, R.R.; Herzog, W.

2009-01-01

History dependent effects on muscle force development following active changes in length have been measured in a number of experimental studies. However, few muscle models have included these properties or examined their impact on force and power output in dynamic cyclic movements. The goal of this study was to develop and validate a modified Hill-type muscle model that includes shortening induced force depression and assess its influence on locomotor performance. The magnitude of force depression was defined by empirical relationships based on muscle mechanical work. To validate the model, simulations incorporating force depression were developed to emulate single muscle in situ and whole muscle group leg extension experiments. There was excellent agreement between simulation and experimental values, with in situ force patterns closely matching the experimental data (average RMS error pedaling with and without force depression were generated. Force depression decreased maximum crank power by 20% – 40%, depending on the relationship between force depression and muscle work used. These results indicate that force depression has the potential to substantially influence muscle power output in dynamic cyclic movements. However, to fully understand the impact of this phenomenon on human movement, more research is needed to characterize the relationship between force depression and mechanical work in large muscles with different morphologies. PMID:19879585

Artificial muscle: facts and fiction.

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Schaub, Marcus C

2011-12-19

Mechanical devices are sought to support insufficient or paralysed striated muscles including the failing heart. Nickel-titanium alloys (nitinol) present the following two properties: (i) super-elasticity, and (ii) the potential to assume different crystal structures depending on temperature and/or stress. Starting from the martensite state nitinol is able to resume the austenite form (state of low potential energy and high entropy) even against an external resistance. This one-way shape change is deployed in self-expanding vascular stents. Heating induces the force generating transformation from martensite to the austenite state while cooling induces relaxation back to the martensite state. This two-way shape change oscillating between the two states may be used in cyclically contracting support devices of silicon-coated nitinol wires. Such a contractile device sutured to the right atrium has been tested in vitro in a bench model and in vivo in sheep. The contraction properties of natural muscles, specifically of the myocardium, and the tight correlation with ATP production by oxidative phosphorylation in the mitochondria is briefly outlined. Force development by the nitinol device cannot be smoothly regulated as in natural muscle. Its mechanical impact is forced onto the natural muscle regardless of the actual condition with regard to metabolism and Ca2+-homeostasis. The development of artificial muscle on the basis of nitinol wires is still in its infancy. The nitinol artificial muscle will have to prove its viability in the various clinical settings.

Pathogenesis of Insulin Resistance in Skeletal Muscle

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Muhammad A. Abdul-Ghani

2010-01-01

Full Text Available Insulin resistance in skeletal muscle is manifested by decreased insulin-stimulated glucose uptake and results from impaired insulin signaling and multiple post-receptor intracellular defects including impaired glucose transport, glucose phosphorylation, and reduced glucose oxidation and glycogen synthesis. Insulin resistance is a core defect in type 2 diabetes, it is also associated with obesity and the metabolic syndrome. Dysregulation of fatty acid metabolism plays a pivotal role in the pathogenesis of insulin resistance in skeletal muscle. Recent studies have reported a mitochondrial defect in oxidative phosphorylation in skeletal muscle in variety of insulin resistant states. In this review, we summarize the cellular and molecular defects that contribute to the development of insulin resistance in skeletal muscle.

FA composition of heart and skeletal muscle during embryonic development of the king penguin.

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Decrock, Frederic; Groscolas, Rene; Speake, Brian K

2002-04-01

Since the yolk lipids of the king penguin (Aptenodytes patagonicus) naturally contain the highest concentrations of DHA and EPA yet reported for the eggs of any avian species, the effects of this (n-3)-rich yolk on the FA profiles of the embryonic heart and skeletal muscle were investigated. The concentrations (mg/g wet tissue) of phospholipid (PL) in the developing heart and leg muscle of the penguin doubled between days 27 and 55 from the beginning of egg incubation (i.e., from the halfway stage of embryonic development to 2 d posthatch), whereas no net increase occurred in pectoral muscle. During this period, the concentration of TAG in heart decreased by half but increased two- and sixfold in leg and pectoral muscle, respectively. The most notable change in cholesteryl ester concentration occurred in pectoral muscle, increasing ninefold between days 27 and 55. Arachidonic acid (ARA) was the major polyunsaturate in PL of the penguin's heart, where it formed about 20% (w/w) of FA at day 55. At the equivalent developmental stage, the heart PL of the chicken contained a 1.3-fold greater proportion of ARA, contained a fifth less DHA, and was almost devoid of EPA, whereas the latter FA was a significant component (7% of FA) of penguin heart PL. Similarly, in PL of leg and pectoral muscle, the chicken displayed about 1.4-fold more ARA, up to 50% less DHA, and far less EPA in comparison with the penguin. Thus, although ARA-rich PL profiles are achieved in the heart and muscle of the penguin embryo, these profiles are significantly affected by the high n-3 content of the yolk.

Fetal development of the pulley for muscle insertion tendons: A review and new findings related to the tensor tympani tendon.

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Rodríguez-Vázquez, Jose Francisco; Honkura, Yohei; Katori, Yukio; Murakami, Gen; Abe, Hiroshi

2017-01-01

The existence of hard tissue pulleys that act to change the direction of a muscle insertion tendon is well known in the human body. These include (1) the trochlea for the extraocular obliquus superior muscle, (2) the pterygoid hamulus for the tensor veli palatini muscle, (3) the deep sulcus on the plantar aspect of the cuboid bone for the peroneus longus tendon, (4) the lesser sciatic notch for the obturator internus muscle, and (5) the bony trochleariformis process for the tensor tympani muscle tendon. In addition, (6) the stapedius muscle tendon shows a lesser or greater angulation at the pyramidal eminence of the temporal bone. Our recent studies have shown that the development of pulleys Nos. 1 and 2 can be explained by a change in the topographical relationship between the pulley and the tendon, that of pulley No. 3 by the rapidly growing calcaneus pushing the tendon, and that of pulley No. 4 by migration of the insertion along the sciatic nerve and gluteus medius tendon. Therefore, in Nos. 1-4, an initially direct tendon curves secondarily and obtains an attachment to the pulley. In case No. 6, the terminal part of the stapedius tendon originates secondarily from the interzone mesenchymal tissue of the incudostapedial joint. In the case of pulley No. 5, we newly demonstrated that its initial phase of development was similar to No. 6, but the tensor tympani tendon achieved a right-angled turn under guidance by a specific fibrous tissue and it migrated along the growing malleus manubrium. Copyright © 2016 Elsevier GmbH. All rights reserved.

Muscle Strength and Muscle Mass in Older Patients during Hospitalization: The EMPOWER Study

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Van Ancum, Jeanine M.; Scheerman, Kira; Pierik, Vincent D.; Numans, Siger T.; Verlaan, Sjors; Smeenk, Hanne E.; Slee-Valentijn, Monique; Kruizinga, Roeliene C.; Meskers, Carel G.M.; Maier, Andrea B.

2017-01-01

Background Low muscle strength and muscle mass are associated with an increased length of hospital stay and higher mortality rate in inpatients. To what extent hospitalization affects muscle strength and muscle mass is unclear. Objective We aimed to assess muscle strength and muscle mass at admission and during hospitalization in older patients and its relation with being at risk of geriatric conditions. Methods The EMPOWER study included patients aged 70 years and older, admitted to 4 wards of the VU University Medical Center in the Netherlands between April and December 2015. At admission, patients were screened for being at risk of 4 geriatric conditions: delirium, falls, malnutrition, and functional disability. At admission and at discharge, muscle strength and muscle mass were assessed. Results A total of 373 patients (mean age, standard deviation [SD]: 79.6, 6.38 years) were included at admission, and 224 patients (mean age, SD: 80.1, 6.32 years) at discharge. At admission, lower muscle strength in both female and male patients and low muscle mass in male patients were associated with being at risk of a higher cumulative number of geriatric conditions. Muscle strength increased during hospitalization, but no change in muscle mass was observed. Changes in muscle measures were not associated with being at risk of geriatric conditions. Discussion Older patients with lower muscle strength and muscle mass at admission were at risk of a higher cumulative number of geriatric conditions. However, being at risk of geriatric conditions did not forecast further decrease in muscle strength and muscle mass during hospitalization PMID:28817825

A different role of angiotensin II type 1a receptor in the development and hypertrophy of plantaris muscle in mice.

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Zempo, Hirofumi; Suzuki, Jun-Ichi; Ogawa, Masahito; Watanabe, Ryo; Isobe, Mitsuaki

2016-02-01

The role of angiotensin II type 1 (AT1) receptors in muscle development and hypertrophy remains unclear. This study was designed to reveal the effects that a loss of AT1 receptors has on skeletal muscle development and hypertrophy in mice. Eight-week-old male AT1a receptor knockout (AT1a(-/-)) mice were used for this experiment. The plantaris muscle to body weight ratio, muscle fiber cross-sectional area, and number of muscle fibers of AT1a(-/-) mice was significantly greater than wild type (WT) mice in the non-intervention condition. Next, the functional overload (OL) model was used to induce plantaris muscle hypertrophy by surgically removing the two triceps muscles consisting of the calf, soleus, and gastrocnemius muscles in mice. After 14 days of OL intervention, the plantaris muscle weight, the amount of fiber, and the fiber area increased. However, the magnitude of the increment of plantaris weight was not different between the two strains. Agtr1a mRNA expression did not change after OL in WT muscle. Actually, the Agt mRNA expression level of WT-OL was lower than WT-Control (C) muscle. An atrophy-related gene, atrogin-1 mRNA expression levels of AT1a(-/-)-C, WT-OL, and AT1a(-/-)-OL muscle were lower than that of WT-C muscle. Our findings suggest that AT1 receptor contributes to plantaris muscle development via atrogin-1 in mice.

Role of skeletal muscle in ear development.

Science.gov (United States)

Rot, Irena; Baguma-Nibasheka, Mark; Costain, Willard J; Hong, Paul; Tafra, Robert; Mardesic-Brakus, Snjezana; Mrduljas-Djujic, Natasa; Saraga-Babic, Mirna; Kablar, Boris

2017-10-01

The current paper is a continuation of our work described in Rot and Kablar, 2010. Here, we show lists of 10 up- and 87 down-regulated genes obtained by a cDNA microarray analysis that compared developing Myf5-/-:Myod-/- (and Mrf4-/-) petrous part of the temporal bone, containing middle and inner ear, to the control, at embryonic day 18.5. Myf5-/-:Myod-/- fetuses entirely lack skeletal myoblasts and muscles. They are unable to move their head, which interferes with the perception of angular acceleration. Previously, we showed that the inner ear areas most affected in Myf5-/-:Myod-/- fetuses were the vestibular cristae ampullaris, sensitive to angular acceleration. Our finding that the type I hair cells were absent in the mutants' cristae was further used here to identify a profile of genes specific to the lacking cell type. Microarrays followed by a detailed consultation of web-accessible mouse databases allowed us to identify 6 candidate genes with a possible role in the development of the inner ear sensory organs: Actc1, Pgam2, Ldb3, Eno3, Hspb7 and Smpx. Additionally, we searched for human homologues of the candidate genes since a number of syndromes in humans have associated inner ear abnormalities. Mutations in one of our candidate genes, Smpx, have been reported as the cause of X-linked deafness in humans. Our current study suggests an epigenetic role that mechanical, and potentially other, stimuli originating from muscle, play in organogenesis, and offers an approach to finding novel genes responsible for altered inner ear phenotypes.

Anatomy of the pectoral and forelimb muscles of wildtype and green fluorescent protein-transgenic axolotls and comparison with other tetrapods including humans: a basis for regenerative, evolutionary and developmental studies

Science.gov (United States)

Diogo, R; Tanaka, E M

2012-01-01

stated in the literature, A. mexicanum has a muscle coracoradialis that has both a well developed proximal fleshy belly and a distal long and thin tendon, supporting the idea that this muscle very likely corresponds to at least part of the amniote biceps brachii. Our observations also: (i) confirmed that the flexores digitorum minimi, interphalangeus digiti 3, pronator quadratus and palmaris profundus 1 are present as distinct muscles in A. mexicanum, supporting the idea that the latter muscle does not correspond to the pronator accessorius of reptiles; (ii) confirmed that the so-called extensor antebrachii radialis is present as a distinct muscle in this species and, importantly, indicated that this muscle corresponds to the supinator of other tetrapods; (iii) showed that, contrary to some other urodeles, including some other Ambystoma species, there is no distinct muscle epitrochleoanconeus in A. mexicanum and; (iv) showed that the ulnar and radial bundles of the abductor et extensor digiti 1 correspond to the abductor pollicis longus and extensor pollicis longus of other tetrapods, respectively. PMID:22957800

Anatomy of the pectoral and forelimb muscles of wildtype and green fluorescent protein-transgenic axolotls and comparison with other tetrapods including humans: a basis for regenerative, evolutionary and developmental studies.

Science.gov (United States)

Diogo, R; Tanaka, E M

2012-12-01

stated in the literature, A. mexicanum has a muscle coracoradialis that has both a well developed proximal fleshy belly and a distal long and thin tendon, supporting the idea that this muscle very likely corresponds to at least part of the amniote biceps brachii. Our observations also: (i) confirmed that the flexores digitorum minimi, interphalangeus digiti 3, pronator quadratus and palmaris profundus 1 are present as distinct muscles in A. mexicanum, supporting the idea that the latter muscle does not correspond to the pronator accessorius of reptiles; (ii) confirmed that the so-called extensor antebrachii radialis is present as a distinct muscle in this species and, importantly, indicated that this muscle corresponds to the supinator of other tetrapods; (iii) showed that, contrary to some other urodeles, including some other Ambystoma species, there is no distinct muscle epitrochleoanconeus in A. mexicanum and; (iv) showed that the ulnar and radial bundles of the abductor et extensor digiti 1 correspond to the abductor pollicis longus and extensor pollicis longus of other tetrapods, respectively. © 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.

The Him gene inhibits the development of Drosophila flight muscles during metamorphosis.

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Soler, Cédric; Taylor, Michael V

2009-07-01

During Drosophila metamorphosis some larval tissues escape the general histolysis and are remodelled to form adult tissues. One example is the dorso-longitudinal muscles (DLMs) of the indirect flight musculature. They are formed by an intriguing process in which residual larval oblique muscles (LOMs) split and fuse with imaginal myoblasts associated with the wing disc. These myoblasts arise in the embryo, but remain undifferentiated throughout embryogenesis and larval life, and thus share characteristics with mammalian satellite cells. However, the mechanisms that maintain the Drosophila myoblasts in an undifferentiated state until needed for LOM remodelling are not understood. Here we show that the Him gene is expressed in these myoblasts, but is undetectable in developing DLM fibres. Consistent with this, we found that Him could inhibit DLM development: it inhibited LOM splitting and resulted in fibre degeneration. We then uncovered a balance between mef2, a positive factor required for proper DLM development, and the inhibitory action of Him. Mef2 suppressed the inhibitory effect of Him on DLM development, while Him could suppress the premature myosin expression induced by mef2 in myoblasts. Furthermore, either decreased Him function or increased mef2 function disrupted DLM development. These findings, together with the co-expression of Him and Mef2 in myoblasts, indicate that Him may antagonise mef2 function during normal DLM development and that Him participates in a balance of signals that controls adult myoblast differentiation and remodelling of these muscle fibres. Lastly, we provide evidence for a link between Notch function and Him and mef2 in this balance.

Brain-muscle-computer interface: mobile-phone prototype development and testing.

Science.gov (United States)

Vernon, Scott; Joshi, Sanjay S

2011-07-01

We report prototype development and testing of a new mobile-phone-based brain-muscle-computer interface for severely paralyzed persons, based on previous results from our group showing that humans may actively create specified power levels in two separate frequency bands of a single surface electromyography (sEMG) signal. EMG activity on the surface of a single face muscle site (auricularis superior) is recorded with a standard electrode. This analog electrical signal is imported into an Android-based mobile phone and digitized via an internal A/D converter. The digital signal is split, and then simultaneously filtered with two band-pass filters to extract total power within two separate frequency bands. The user-modulated power in each frequency band serves as two separate control channels for machine control. After signal processing, the Android phone sends commands to external devices via a Bluetooth interface. Users are trained to use the device via visually based operant conditioning, with simple cursor-to-target activities on the phone screen. The mobile-phone prototype interface is formally evaluated on a single advanced Spinal Muscle Atrophy subject, who has successfully used the interface in his home in evaluation trials and for remote control of a television. Development of this new device will not only guide future interface design for community use, but will also serve as an information technology bridge for in situ data collection to quantify human sEMG manipulation abilities for a relevant population.

ATP and phosphocreatine utilization in single human muscle fibres during the development of maximal power output at elevated muscle temperatures.

Science.gov (United States)

Gray, Stuart R; Söderlund, Karin; Ferguson, Richard A

2008-05-01

In this study, we examined the effect of muscle temperature (Tm) on adenosine triphosphate (ATP) and phosphocreatine utilization in single muscle fibres during the development of maximal power output in humans. Six male participants performed a 6-s maximal sprint on a friction-braked cycle ergometer under both normal (Tm = 34.3 degrees C, s = 0.6) and elevated (T(m) = 37.3 degrees C, s = 0.2) muscle temperature conditions. During the elevated condition, muscle temperature of the legs was raised, passively, by hot water immersion followed by wrapping in electrically heated blankets. Muscle biopsies were taken from the vastus lateralis before and immediately after exercise. Freeze-dried single fibres were dissected, characterized according to myosin heavy chain composition, and analysed for ATP and phosphocreatine content. Single fibres were classified as: type I, IIA, IIAX25 (1 - 25% IIX isoform), IIAX50 (26 - 50% IIX), IIAX75 (51 - 75% IIX), or IIAX100 (76 - 100% IIX). Maximal power output and pedal rate were both greater (P < 0.05) during the elevated condition by 258 W (s = 110) and 22 rev . min(-1) (s = 6), respectively. In both conditions, phosphocreatine content decreased significantly in all fibre types, with a greater decrease during the elevated condition in type IIA fibres (P < 0.01). Adenosine triphosphate content was also reduced to a greater (P < 0.01) extent in type IIA fibres during the elevated condition. The results of the present study indicate that after passive elevation of muscle temperature, there was a greater decrease in ATP and phosphocreatine content in type IIA fibres than in the normal trial, which contributed to the higher maximal power output.

Brain cytoplasmic RNA 1 suppresses smooth muscle differentiation and vascular development in mice.

Science.gov (United States)

Wang, Yung-Chun; Chuang, Ya-Hui; Shao, Qiang; Chen, Jian-Fu; Chen, Shi-You

2018-04-13

The cardiovascular system develops during the early stages of embryogenesis, and differentiation of smooth muscle cells (SMCs) is essential for that process. SMC differentiation is critically regulated by transforming growth factor (TGF)-β/SMAD family member 3 (SMAD3) signaling, but other regulators may also play a role. For example, long noncoding RNAs (lncRNAs) regulate various cellular activities and events, such as proliferation, differentiation, and apoptosis. However, whether long noncoding RNAs also regulate SMC differentiation remains largely unknown. Here, using the murine cell line C3H10T1/2, we found that brain cytoplasmic RNA 1 (BC1) is an important regulator of SMC differentiation. BC1 overexpression suppressed, whereas BC1 knockdown promoted, TGF-β-induced SMC differentiation, as indicated by altered cell morphology and expression of multiple SMC markers, including smooth muscle α-actin (αSMA), calponin, and smooth muscle 22α (SM22α). BC1 appeared to block SMAD3 activity and inhibit SMC marker gene transcription. Mechanistically, BC1 bound to SMAD3 via RNA SMAD-binding elements (rSBEs) and thus impeded TGF-β-induced SMAD3 translocation to the nucleus. This prevented SMAD3 from binding to SBEs in SMC marker gene promoters, an essential event in SMC marker transcription. In vivo , BC1 overexpression in mouse embryos impaired vascular SMC differentiation, leading to structural defects in the artery wall, such as random breaks in the elastic lamina, abnormal collagen deposition on SM fibers, and disorganized extracellular matrix proteins in the media of the neonatal aorta. Our results suggest that BC1 is a suppressor of SMC differentiation during vascular development. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

The expression of myosin genes in developing skeletal muscle in the mouse embryo

International Nuclear Information System (INIS)

Lyons, G.E.; Ontell, M.; Cox, R.; Sassoon, D.; Buckingham, M.

1990-01-01

Using in situ hybridization, we have investigated the temporal sequence of myosin gene expression in the developing skeletal muscle masses of mouse embryos. The probes used were isoform-specific, 35S-labeled antisense cRNAs to the known sarcomeric myosin heavy chain and myosin alkali light chain gene transcripts. Results showed that both cardiac and skeletal myosin heavy chain and myosin light chain mRNAs were first detected between 9 and 10 d post coitum (p.c.) in the myotomes of the most rostral somites. Myosin transcripts appeared in more caudal somites at later stages in a developmental gradient. The earliest myosin heavy chain transcripts detected code for the embryonic skeletal (MHCemb) and beta-cardiac (MHC beta) isoforms. Perinatal myosin heavy chain (MHCpn) transcripts begin to accumulate at 10.5 d p.c., which is much earlier than previously reported. At this stage, MHCemb is the major MHC transcript. By 12.5 d p.c., MHCpn and MHCemb mRNAs are present to an equal extent, and by 15.5 d p.c. the MHCpn transcript is the major MHC mRNA detected. Cardiac MHC beta transcripts are always present as a minor component. In contrast, the cardiac MLC1A mRNA is initially more abundant than that encoding the skeletal MLC1F isoform. By 12.5 d p.c. the two MLC mRNAs are present at similar levels, and by 15.5 d p.c., MLC1F is the predominant MLC transcript detected. Transcripts for the ventricular/slow (MLC1V) and another fast skeletal myosin light chain (MLC3F) are not detected in skeletal muscle before 15 d p.c., which marks the beginning of the fetal stage of muscle development. This is the first stage at which we can detect differences in expression of myosin genes between developing muscle fibers. We conclude that, during the development of the myotome and body wall muscles, different myosin genes follow independent patterns of activation and acculumation

Cavin4b/Murcb Is Required for Skeletal Muscle Development and Function in Zebrafish.

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Housley, Michael P; Njaine, Brian; Ricciardi, Filomena; Stone, Oliver A; Hölper, Soraya; Krüger, Marcus; Kostin, Sawa; Stainier, Didier Y R

2016-06-01

Skeletal muscles provide metazoans with the ability to feed, reproduce and avoid predators. In humans, a heterogeneous group of genetic diseases, termed muscular dystrophies (MD), lead to skeletal muscle dysfunction. Mutations in the gene encoding Caveolin-3, a principal component of the membrane micro-domains known as caveolae, cause defects in muscle maintenance and function; however it remains unclear how caveolae dysfunction underlies MD pathology. The Cavin family of caveolar proteins can form membrane remodeling oligomers and thus may also impact skeletal muscle function. Changes in the distribution and function of Cavin4/Murc, which is predominantly expressed in striated muscles, have been reported to alter caveolae structure through interaction with Caveolin-3. Here, we report the generation and phenotypic analysis of murcb mutant zebrafish, which display impaired swimming capacity, skeletal muscle fibrosis and T-tubule abnormalities during development. To understand the mechanistic importance of Murc loss of function, we assessed Caveolin-1 and 3 localization and found it to be abnormal. We further identified an in vivo function for Murc in Erk signaling. These data link Murc with developmental defects in T-tubule formation and progressive muscle dysfunction, thereby providing a new candidate for the etiology of muscular dystrophy.

Cavin4b/Murcb Is Required for Skeletal Muscle Development and Function in Zebrafish.

Directory of Open Access Journals (Sweden)

Michael P Housley

2016-06-01

Full Text Available Skeletal muscles provide metazoans with the ability to feed, reproduce and avoid predators. In humans, a heterogeneous group of genetic diseases, termed muscular dystrophies (MD, lead to skeletal muscle dysfunction. Mutations in the gene encoding Caveolin-3, a principal component of the membrane micro-domains known as caveolae, cause defects in muscle maintenance and function; however it remains unclear how caveolae dysfunction underlies MD pathology. The Cavin family of caveolar proteins can form membrane remodeling oligomers and thus may also impact skeletal muscle function. Changes in the distribution and function of Cavin4/Murc, which is predominantly expressed in striated muscles, have been reported to alter caveolae structure through interaction with Caveolin-3. Here, we report the generation and phenotypic analysis of murcb mutant zebrafish, which display impaired swimming capacity, skeletal muscle fibrosis and T-tubule abnormalities during development. To understand the mechanistic importance of Murc loss of function, we assessed Caveolin-1 and 3 localization and found it to be abnormal. We further identified an in vivo function for Murc in Erk signaling. These data link Murc with developmental defects in T-tubule formation and progressive muscle dysfunction, thereby providing a new candidate for the etiology of muscular dystrophy.

Oropharyngeal Dysphagia in Dermatomyositis: Associations with Clinical and Laboratory Features Including Autoantibodies.

Science.gov (United States)

Mugii, Naoki; Hasegawa, Minoru; Matsushita, Takashi; Hamaguchi, Yasuhito; Oohata, Sacihe; Okita, Hirokazu; Yahata, Tetsutarou; Someya, Fujiko; Inoue, Katsumi; Murono, Shigeyuki; Fujimoto, Manabu; Takehara, Kazuhiko

2016-01-01

Dysphagia develops with low frequency in patients with dermatomyositis. Our objective was to determine the clinical and laboratory features that can estimate the development of dysphagia in dermatomyositis. This study included 92 Japanese patients with adult-onset dermatomyositis. The associations between dysphagia and clinical and laboratory features including disease-specific autoantibodies determined by immunoprecipitation assays were analyzed. Videofluoroscopy swallow study (VFSS) was performed for all patients with clinical dysphagia (n = 13, 14.1%) but not for patients without clinical dysphagia. Typical findings of dysphagia (pharyngeal pooling, n = 11 and/or nasal regurgitation, n = 4) was detected by VFSS in all patients with clinical dysphagia. Eleven patients with dysphagia (84.6%) had anti-transcription intermediary factor 1γ (TIF-1γ) antibody. By univariate analysis, the average age and the male to female ratio, internal malignancy, and anti-TIF-1γ antibody were significantly higher and the frequency of interstitial lung diseases and manual muscle testing (MMT) scores of sternomastoid and dertoid muscles were significantly lower in patients with dysphagia than in patients without dysphagia. Among patients with anti-TIF-1γ antibody, the mean age, the ratios of male to female and internal malignancy were significantly higher and mean MMT scores of sternomastoid muscle were significantly lower in patients with dysphagia compared with patients without dysphagia. By multivariable analysis, the risk of dysphagia was strongly associated with the existence of internal malignancy and ant-TIF-1γ antibody and was also associated with reduced scores of manual muscle test of sternomastoid muscle. Dysphagia was markedly improved after the treatment against myositis in all 13 patients. These findings indicate that dysphagia can develop frequently in patients with internal malignancy, anti-TIF-1γ antibody, or severe muscle weakness of sternomastoid muscle.

Physiological and methodological aspects of rate of force development assessment in human skeletal muscle

DEFF Research Database (Denmark)

Rodríguez-Rosell, David; Pareja-Blanco, Fernando; Aagaard, Per

2018-01-01

Rate of force development (RFD) refers to the ability of the neuromuscular system to increase contractile force from a low or resting level when muscle activation is performed as quickly as possible, and it is considered an important muscle strength parameter, especially for athletes in sports re......, which may aid to clarify the thinking of coaches and sports scientists in this area....

Shoulder muscle endurance: the development of a standardized and reliable protocol

Directory of Open Access Journals (Sweden)

Roy Jean-Sébastien

2011-01-01

Full Text Available Abstract Background Shoulder muscle fatigue has been proposed as a possible link to explain the association between repetitive arm use and the development of rotator cuff disorders. To our knowledge, no standardized clinical endurance protocol has been developed to evaluate the effects of muscle fatigue on shoulder function. Such a test could improve clinical examination of individuals with shoulder disorders. Therefore, the purpose of this study was to establish a reliable protocol for objective assessment of shoulder muscle endurance. Methods An endurance protocol was developed on a stationary dynamometer (Biodex System 3. The endurance protocol was performed in isotonic mode with the resistance set at 50% of each subject's peak torque as measured for shoulder external (ER and internal rotation (IR. Each subject performed 60 continuous repetitions of IR/ER rotation. The endurance protocol was performed by 36 healthy individuals on two separate occasions at least two days apart. Maximal isometric shoulder strength tests were performed before and after the fatigue protocol to evaluate the effects of the endurance protocol and its reliability. Paired t-tests were used to evaluate the reduction in shoulder strength due to the protocol, while intraclass correlation coefficients (ICC and minimal detectable change (MDC were used to evaluate its reliability. Results Maximal isometric strength was significantly decreased after the endurance protocol (P 0.84. Conclusions Changes in muscular performance observed during and after the muscular endurance protocol suggests that the protocol did result in muscular fatigue. Furthermore, this study established that the resultant effects of fatigue of the proposed isotonic protocol were reproducible over time. The protocol was performed without difficulty by all volunteers and took less than 10 minutes to perform, suggesting that it might be feasible for clinical practice. This protocol could be used to induce

Primary skeletal muscle cells cultured on gelatin bead microcarriers develop structural and biochemical features characteristic of adult skeletal muscle.

Science.gov (United States)

Kubis, Hans-Peter; Scheibe, Renate J; Decker, Brigitte; Hufendiek, Karsten; Hanke, Nina; Gros, Gerolf; Meissner, Joachim D

2016-04-01

A primary skeletal muscle cell culture, in which myoblasts derived from newborn rabbit hindlimb muscles grow on gelatin bead microcarriers in suspension and differentiate into myotubes, has been established previously. In the course of differentiation and beginning spontaneous contractions, these multinucleated myotubes do not detach from their support. Here, we describe the development of the primary myotubes with respect to their ultrastructural differentiation. Scanning electron microscopy reveals that myotubes not only grow around the surface of one carrier bead but also attach themselves to neighboring carriers, forming bridges between carriers. Transmission electron microscopy demonstrates highly ordered myofibrils, T-tubules, and sarcoplasmic reticulum. The functionality of the contractile apparatus is evidenced by contractile activity that occurs spontaneously or can be elicited by electrostimulation. Creatine kinase activity increases steadily until day 20 of culture. Regarding the expression of isoforms of myosin heavy chains (MHC), we could demonstrate that from day 16 on, no non-adult MHC isoform mRNAs are present. Instead, on day 28 the myotubes express predominantly adult fast MHCIId/x mRNA and protein. This MHC pattern resembles that of fast muscles of adult rabbits. In contrast, primary myotubes grown on matrigel-covered culture dishes express substantial amounts of non-adult MHC protein even on day 21. To conclude, primary myotubes grown on microcarriers in their later stages exhibit many features of adult skeletal muscle and characteristics of fast type II fibers. Thus, the culture represents an excellent model of adult fast skeletal muscle, for example, when investigating molecular mechanisms of fast-to-slow fiber-type transformation. © 2015 International Federation for Cell Biology.

Engineered skeletal muscle tissue for soft robotics: fabrication strategies, current applications, and future challenges.

Science.gov (United States)

Duffy, Rebecca M; Feinberg, Adam W

2014-01-01

Skeletal muscle is a scalable actuator system used throughout nature from the millimeter to meter length scales and over a wide range of frequencies and force regimes. This adaptability has spurred interest in using engineered skeletal muscle to power soft robotics devices and in biotechnology and medical applications. However, the challenges to doing this are similar to those facing the tissue engineering and regenerative medicine fields; specifically, how do we translate our understanding of myogenesis in vivo to the engineering of muscle constructs in vitro to achieve functional integration with devices. To do this researchers are developing a number of ways to engineer the cellular microenvironment to guide skeletal muscle tissue formation. This includes understanding the role of substrate stiffness and the mechanical environment, engineering the spatial organization of biochemical and physical cues to guide muscle alignment, and developing bioreactors for mechanical and electrical conditioning. Examples of engineered skeletal muscle that can potentially be used in soft robotics include 2D cantilever-based skeletal muscle actuators and 3D skeletal muscle tissues engineered using scaffolds or directed self-organization. Integration into devices has led to basic muscle-powered devices such as grippers and pumps as well as more sophisticated muscle-powered soft robots that walk and swim. Looking forward, current, and future challenges include identifying the best source of muscle precursor cells to expand and differentiate into myotubes, replacing cardiomyocytes with skeletal muscle tissue as the bio-actuator of choice for soft robots, and vascularization and innervation to enable control and nourishment of larger muscle tissue constructs. © 2013 Wiley Periodicals, Inc.

Evaluation of muscle hyperactivity of the grimacing muscles by unilateral tight eyelid closure and stapedius muscle tone.

Science.gov (United States)

Shiba, Masato; Matsuo, Kiyoshi; Ban, Ryokuya; Nagai, Fumio

2012-10-01

Muscle hyperactivity of grimacing muscles, including the orbicularis oculi and corrugator supercilii muscles that cause crow's feet and a glabellar frown line with ageing, cannot be accurately evaluated by surface observation. In 71 subjects, this study investigated the extent to which grimacing muscles are innervated by the bilateral motor cortices, whether the corticofacial projection to the grimacing muscles affects the facially innervated stapedius muscle tone by measuring static compliance of the tympanic membrane, and whether unilateral tight eyelid closure with contraction of the grimacing muscles changes static compliance. Unilateral tight eyelid closure and its subsequent change in the contralateral vertical medial eyebrow position revealed that motor neurons of the orbicularis oculi and corrugator supercilii muscles were innervated by the bilateral motor cortices with weak-to-strong contralateral dominance. The orbicularis oculi, corrugator supercilii, and stapedius muscles innervated by the bilateral motor cortices had increased muscle hyperactivity, which lowered the vertical medial eyebrow position and decreased the static compliance of the tympanic membrane more than those innervated by the unilateral motor cortex. Unilateral enhanced tight eyelid closure with contraction of the grimacing muscles in certain subjects ipsilaterally decreased the static compliance with increased contraction of the stapedius muscle, which probably occurs to immobilise the tympanic membrane and protect the inner ear from loud sound. Evaluation of unilateral tight eyelid closure and the subsequent change in the contralateral vertical medial eyebrow position as well as a measurement of the static compliance for the stapedius muscle tone has revealed muscle hyperactivity of grimacing muscles.

Fluid-driven origami-inspired artificial muscles

Science.gov (United States)

Li, Shuguang; Vogt, Daniel M.; Rus, Daniela; Wood, Robert J.

2017-12-01

Artificial muscles hold promise for safe and powerful actuation for myriad common machines and robots. However, the design, fabrication, and implementation of artificial muscles are often limited by their material costs, operating principle, scalability, and single-degree-of-freedom contractile actuation motions. Here we propose an architecture for fluid-driven origami-inspired artificial muscles. This concept requires only a compressible skeleton, a flexible skin, and a fluid medium. A mechanical model is developed to explain the interaction of the three components. A fabrication method is introduced to rapidly manufacture low-cost artificial muscles using various materials and at multiple scales. The artificial muscles can be programed to achieve multiaxial motions including contraction, bending, and torsion. These motions can be aggregated into systems with multiple degrees of freedom, which are able to produce controllable motions at different rates. Our artificial muscles can be driven by fluids at negative pressures (relative to ambient). This feature makes actuation safer than most other fluidic artificial muscles that operate with positive pressures. Experiments reveal that these muscles can contract over 90% of their initial lengths, generate stresses of ˜600 kPa, and produce peak power densities over 2 kW/kg—all equal to, or in excess of, natural muscle. This architecture for artificial muscles opens the door to rapid design and low-cost fabrication of actuation systems for numerous applications at multiple scales, ranging from miniature medical devices to wearable robotic exoskeletons to large deployable structures for space exploration.

Effect of resistance training on muscle strength and rate of force development in healthy older adults: A systematic review and meta-analysis.

Science.gov (United States)

Guizelini, Pedrode Camargo; de Aguiar, Rafael Alves; Denadai, Benedito Sérgio; Caputo, Fabrizio; Greco, Camila Coelho

2018-02-01

Rapid force capacity, identified by rate of rise in contractile force at the onset of contraction, i.e., the rate of force development (RFD), has been considered an important neuromuscular parameter of physical fitness in elderly individuals. Randomized control studies conducted in adults have found that resistance training may elicit different outcomes in terms of RFD and muscle strength. Thus, the main purpose of this study was to review systematically the literature for studies regarding the influence of resistance training on muscle strength and RFD in elderly persons. A literature search was performed in major electronic databases from inception to March 2017. Studies including health individuals with a mean age≥60years, describing the effect of resistance training on RFD and muscle strength were found eligible. The outcomes were calculated as the difference in percentage change between control and experimental groups (% change) and data were presented as mean±95% confidence limits. Meta-analyses were performed using a random-effects model and, in addition, simple and multiple meta-regression analyses were used to identify effects of age, training type, sessions per week and training duration on % change in RFD and muscle strength. Thirteen training effects were collected from 10 studies included in the meta-analysis. The resistance training program had a moderate beneficial effect on both muscle strength (% change=18.40%, 95% CL 13.69-23.30, pchange=26.68, 95% CL 14.41-35.52, pchanges in muscle strength and RFD. It can be concluded that explosive training and heavy strength training are effective resistance training methods aiming to improve both muscle strength and RFD after short-to-medium training period. However, muscle strength and RFD seem to adapt differently to resistance training programs, suggesting caution for their interchangeable use in clinical assessments of the elderly. Copyright © 2017 Elsevier Inc. All rights reserved.

Prediction model for recurrence probabilities after intravesical chemotherapy in patients with intermediate-risk non-muscle-invasive bladder cancer, including external validation

NARCIS (Netherlands)

Lammers, R.J.M.; Hendriks, J.C.M.; Rodriguez Faba, O.; Witjes, W.P.J.; Palou, J.; Witjes, J.A.

2016-01-01

PURPOSE: To develop a model to predict recurrence for patients with intermediate-risk (IR) non-muscle-invasive bladder cancer (NMIBC) treated with intravesical chemotherapy which can be challenging because of the heterogeneous characteristics of these patients. METHODS: Data from three Dutch trials

Activation of respiratory muscles during respiratory muscle training.

Science.gov (United States)

Walterspacher, Stephan; Pietsch, Fabian; Walker, David Johannes; Röcker, Kai; Kabitz, Hans-Joachim

2018-01-01

It is unknown which respiratory muscles are mainly activated by respiratory muscle training. This study evaluated Inspiratory Pressure Threshold Loading (IPTL), Inspiratory Flow Resistive Loading (IFRL) and Voluntary Isocapnic Hyperpnea (VIH) with regard to electromyographic (EMG) activation of the sternocleidomastoid muscle (SCM), parasternal muscles (PARA) and the diaphragm (DIA) in randomized order. Surface EMG were analyzed at the end of each training session and normalized using the peak EMG recorded during maximum inspiratory maneuvers (Sniff nasal pressure: SnPna, maximal inspiratory mouth occlusion pressure: PImax). 41 healthy participants were included. Maximal activation was achieved for SCM by SnPna; the PImax activated predominantly PARA and DIA. Activations of SCM and PARA were higher in IPTL and VIH than for IFRL (p<0.05). DIA was higher applying IPTL compared to IFRL or VIH (p<0.05). IPTL, IFRL and VIH differ in activation of inspiratory respiratory muscles. Whereas all methods mainly stimulate accessory respiratory muscles, diaphragm activation was predominant in IPTL. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of oblique muscle surgery on the rectus muscle pulley

International Nuclear Information System (INIS)

Okanobu, Hirotaka; Kono, Reika; Ohtsuki, Hiroshi

2011-01-01

The purpose of this study was to determine the position of rectus muscle pulleys in Japanese eyes and to evaluate the effect of oblique muscle surgery on rectus muscle pulleys. Quasi-coronal plane MRI was used to determine area centroids of the 4 rectus muscles. The area centroids of the rectus muscles were transformed to 2-dimensional coordinates to represent pulley positions. The effects of oblique muscle surgery on the rectus muscle pulley positions in the coronal plane were evaluated in 10 subjects with cyclovertical strabismus and, as a control, pulley locations in 7 normal Japanese subjects were calculated. The mean positions of the rectus muscle pulleys in the coronal plane did not significantly differ from previous reports on normal populations, including Caucasians. There were significant positional shifts of the individual horizontal and vertical rectus muscle pulleys in 3 (100%) patients with inferior oblique advancement, but not in eyes with inferior oblique recession and superior oblique tendon advancement surgery. The surgical cyclorotatory effect was significantly correlated with the change in the angle of inclination formed by the line connecting the vertical rectus muscles (p=0.0234), but weakly correlated with that of the horizontal rectus muscles. The most important factor that affects the pulley position is the amount of ocular torsion, not the difference in surgical procedure induced by oblique muscle surgery. (author)

Effects of different rearing temperatures on muscle development and stress response in the early larval stages of Acipenser baerii

Directory of Open Access Journals (Sweden)

Lucia Aidos

2017-11-01

Full Text Available The present study aims at investigating muscle development and stress response in early stages of Siberian sturgeon when subjected to different rearing temperatures, by analysing growth and development of the muscle and by assessing the stress response of yolk-sac larvae. Siberian sturgeon larvae were reared at 16°C, 19°C and 22°C until the yolk-sac was completely absorbed. Sampling timepoints were: hatching, schooling and complete yolk-sac absorption stage. Histometrical, histochemical and immunohistochemical analyses were performed in order to characterize muscle growth (total muscle area, TMA; slow muscle area, SMA; fast muscle area, FMA, development (anti-proliferating cell nuclear antigen -PCNA or anticaspase as well as stress conditions by specific stress biomarkers (heat shock protein 70 or 90, HSP70 or HSP90. Larvae subjected to the highest water temperature showed a faster yolk-sac absorption. Histometry revealed that both TMA and FMA were larger in the schooling stage at 19°C while no differences were observed in the SMA at any of the tested rearing temperatures. PCNA quantification revealed a significantly higher number of proliferating cells in the yolk-sac absorption phase at 22°C than at 16°C. HSP90 immunopositivity seems to be particularly evident at 19°C. HPS70 immunopositivity was never observed in the developing lateral muscle.

Poorly Understood Aspects of Striated Muscle Contraction

Directory of Open Access Journals (Sweden)

Alf Månsson

2015-01-01

Full Text Available Muscle contraction results from cyclic interactions between the contractile proteins myosin and actin, driven by the turnover of adenosine triphosphate (ATP. Despite intense studies, several molecular events in the contraction process are poorly understood, including the relationship between force-generation and phosphate-release in the ATP-turnover. Different aspects of the force-generating transition are reflected in the changes in tension development by muscle cells, myofibrils and single molecules upon changes in temperature, altered phosphate concentration, or length perturbations. It has been notoriously difficult to explain all these events within a given theoretical framework and to unequivocally correlate observed events with the atomic structures of the myosin motor. Other incompletely understood issues include the role of the two heads of myosin II and structural changes in the actin filaments as well as the importance of the three-dimensional order. We here review these issues in relation to controversies regarding basic physiological properties of striated muscle. We also briefly consider actomyosin mutation effects in cardiac and skeletal muscle function and the possibility to treat these defects by drugs.

Myosin heavy chain expression in rabbit masseter muscle during postnatal development

NARCIS (Netherlands)

Bredman, J. J.; Weijs, W. A.; Korfage, H. A.; Brugman, P.; Moorman, A. F.

1992-01-01

The expression of isoforms of myosin heavy chain (MHC) during postnatal development was studied in the masseter muscle of the rabbit. Evidence is presented that in addition to adult fast and slow myosin, the rabbit masseter contains neonatal and 'cardiac' alpha-MHC. During postnatal growth myosin

First comparative study of primate morphological and molecular evolutionary rates including muscle data: implications for the tempo and mode of primate and human evolution

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Diogo, Rui; Peng, Zuogang; Wood, Bernard

2013-01-01

Here we provide the first report about the rates of muscle evolution derived from Bayesian and parsimony cladistic analyses of primate higher-level phylogeny, and compare these rates with published rates of molecular evolution. It is commonly accepted that there is a ‘general molecular slow-down of hominoids’, but interestingly the rates of muscle evolution in the nodes leading and within the hominoid clade are higher than those in the vast majority of other primate clades. The rate of muscle evolution at the node leading to Homo (1.77) is higher than that at the nodes leading to Pan (0.89) and particularly to Gorilla (0.28). Notably, the rates of muscle evolution at the major euarchontan and primate nodes are different, but within each major primate clade (Strepsirrhini, Platyrrhini, Cercopithecidae and Hominoidea) the rates at the various nodes, and particularly at the nodes leading to the higher groups (i.e. including more than one genera), are strikingly similar. We explore the implications of these new data for the tempo and mode of primate and human evolution. PMID:23320764

Patterning Muscles Using Organizers: Larval Muscle Templates and Adult Myoblasts Actively Interact to Pattern the Dorsal Longitudinal Flight Muscles of Drosophila

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Roy, Sudipto; VijayRaghavan, K.

1998-01-01

Pattern formation in muscle development is often mediated by special cells called muscle organizers. During metamorphosis in Drosophila, a set of larval muscles function as organizers and provide scaffolding for the development of the dorsal longitudinal flight muscles. These organizers undergo defined morphological changes and dramatically split into templates as adult fibers differentiate during pupation. We have investigated the cellular mechanisms involved in the use of larval fibers as templates. Using molecular markers that label myoblasts and the larval muscles themselves, we show that splitting of the larval muscles is concomitant with invasion by imaginal myoblasts and the onset of differentiation. We show that the Erect wing protein, an early marker of muscle differentiation, is not only expressed in myoblasts just before and after fusion, but also in remnant larval nuclei during muscle differentiation. We also show that interaction between imaginal myoblasts and larval muscles is necessary for transformation of the larval fibers. In the absence of imaginal myoblasts, the earliest steps in metamorphosis, such as the escape of larval muscles from histolysis and changes in their innervation, are normal. However, subsequent events, such as the splitting of these muscles, fail to progress. Finally, we show that in a mutant combination, null for Erect wing function in the mesoderm, the splitting of the larval muscles is aborted. These studies provide a genetic and molecular handle for the understanding of mechanisms underlying the use of muscle organizers in muscle patterning. Since the use of such organizers is a common theme in myogenesis in several organisms, it is likely that many of the processes that we describe are conserved. PMID:9606206

Development of a phantom mimicking the functional and structural behaviors of the thigh muscles characterized with magnetic resonance elastography technique.

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Chakouch, Mashhour K; Charleux, Fabrice; Bensamoun, Sabine F

2015-01-01

Magnetic Resonance Elastography (MRE) is a non invasive technique based on the propagation of shear waves in soft tissues providing the quantification of the mechanical properties [1]. MRE was successfully applied to healthy and pathological muscles. However, the MRE muscle methods must be further improved to characterize the deep muscles. A way will be to develop phantom mimicking the muscle behavior in order to set up new MRE protocol. Thus, the purpose of this study is to create a phantom composed of a similar skeletal muscle architecture (fiber, aponorosis) and equivalent elastic properties as a function of the muscle state (passive or active). Two homogeneous phantoms were manufactured with different concentrations of plastisol to simulate the elastic properties in relaxed (50% of plastisol) and contracted (70% of plastisol) muscle conditions. Moreover, teflon tubing pipes (D = 0.9 mm) were thread in the upper part of the phantom (50%) to represent the muscle fibers and a plastic sheet (8 × 15 cm) was also included in the middle of the phantom to mimic the aponeurosis structure. Subsequently, MRE tests were performed with two different pneumatic drivers, tube and round, (f = 90Hz) to analyze the effect of the type of driver on the wave propagation. Then, the wavelength was measured from the phase images to obtain the elastic properties (shear modulus). Both phantoms revealed elastic properties which were in the same range as in vivo muscle in passive (μ(50%) = 2.40 ± 0.18 kPa ) and active (6.24 ± 0.21 kPa) states. The impact of the type of driver showed higher values (about 1.2kPa) with the tube. The analysis of the wave behavior revealed a sliding along the plastic sheet as it was observed for in vivo muscle study. The wave was also sensitive to the presence of the fibers where gaps were identified. The present study demonstrates the ability of the phantom to mimic the structural and functional properties of the muscle.

Fluid-driven origami-inspired artificial muscles.

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Li, Shuguang; Vogt, Daniel M; Rus, Daniela; Wood, Robert J

2017-12-12

Artificial muscles hold promise for safe and powerful actuation for myriad common machines and robots. However, the design, fabrication, and implementation of artificial muscles are often limited by their material costs, operating principle, scalability, and single-degree-of-freedom contractile actuation motions. Here we propose an architecture for fluid-driven origami-inspired artificial muscles. This concept requires only a compressible skeleton, a flexible skin, and a fluid medium. A mechanical model is developed to explain the interaction of the three components. A fabrication method is introduced to rapidly manufacture low-cost artificial muscles using various materials and at multiple scales. The artificial muscles can be programed to achieve multiaxial motions including contraction, bending, and torsion. These motions can be aggregated into systems with multiple degrees of freedom, which are able to produce controllable motions at different rates. Our artificial muscles can be driven by fluids at negative pressures (relative to ambient). This feature makes actuation safer than most other fluidic artificial muscles that operate with positive pressures. Experiments reveal that these muscles can contract over 90% of their initial lengths, generate stresses of ∼600 kPa, and produce peak power densities over 2 kW/kg-all equal to, or in excess of, natural muscle. This architecture for artificial muscles opens the door to rapid design and low-cost fabrication of actuation systems for numerous applications at multiple scales, ranging from miniature medical devices to wearable robotic exoskeletons to large deployable structures for space exploration. Copyright © 2017 the Author(s). Published by PNAS.

Development of nylon-based artificial muscles for the usage in robotic prosthetic limb

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Atikah, Nurul Anis; Weng, Leong Yeng; Anuar, Adzly; Fat, Chau Chien; Abidin, Izham Zainal; Sahari, Khairul Salleh Mohamed

2017-09-01

This paper describes the development of nylon-based artificial muscles that is intended to be used in prosthetic limb for young amputees. Prosthetic limbs are very expensive and this situation is further compounded for young amputees who are very quickly out-grow their prosthesis. The proposed artificial muscles are made of nylon fishing strings from various size such as 0.45mm, 0.55mm, 0.65mm and 1.00mm. These fishing strings were twisted into coils to create Super Coiled Polymers (SCP) and tested using hot air blower. These artificial muscles react counterintuitively, where when it is exposed to heat, contracts, and when cooled, expands. Peltier devices, when switched-on acts as heat pump, where one side is hot and the other is cold. This phenomenon, when affixed in between 2 SCP's, creates tandem motion similar to triceps and biceps. As initial study, the hot side of the Peltier module was tested using these artificial muscles. The string was measured for both its force production, length contraction, the initial results were promising.

Cell fate determination in zebrafish embryonic and adult muscle development

NARCIS (Netherlands)

Tee, J.M.

2010-01-01

We are interested in how the genetic basis of muscle precursor cells determines the outcome of the muscle cell fate, and thus leading to disruption in muscle formation and maintenance. We utilized the zebrafish carrying mutations in both Axin1 and Apc1, resulting in overactivation of the

Ethanol Exposure Causes Muscle Degeneration in Zebrafish

Directory of Open Access Journals (Sweden)

Elizabeth C. Coffey

2018-03-01

Full Text Available Alcoholic myopathies are characterized by neuromusculoskeletal symptoms such as compromised movement and weakness. Although these symptoms have been attributed to neurological damage, EtOH may also target skeletal muscle. EtOH exposure during zebrafish primary muscle development or adulthood results in smaller muscle fibers. However, the effects of EtOH exposure on skeletal muscle during the growth period that follows primary muscle development are not well understood. We determined the effects of EtOH exposure on muscle during this phase of development. Strikingly, muscle fibers at this stage are acutely sensitive to EtOH treatment: EtOH induces muscle degeneration. The severity of EtOH-induced muscle damage varies but muscle becomes more refractory to EtOH as muscle develops. NF-kB induction in muscle indicates that EtOH triggers a pro-inflammatory response. EtOH-induced muscle damage is p53-independent. Uptake of Evans blue dye shows that EtOH treatment causes sarcolemmal instability before muscle fiber detachment. Dystrophin-null sapje mutant zebrafish also exhibit sarcolemmal instability. We tested whether Trichostatin A (TSA, which reduces muscle degeneration in sapje mutants, would affect EtOH-treated zebrafish. We found that TSA and EtOH are a lethal combination. EtOH does, however, exacerbate muscle degeneration in sapje mutants. EtOH also disrupts adhesion of muscle fibers to their extracellular matrix at the myotendinous junction: some detached muscle fibers retain beta-Dystroglycan indicating failure of muscle end attachments. Overexpression of Paxillin, which reduces muscle degeneration in zebrafish deficient for beta-Dystroglycan, is not sufficient to rescue degeneration. Taken together, our results suggest that EtOH exposure has pleiotropic deleterious effects on skeletal muscle.

The Him gene reveals a balance of inputs controlling muscle differentiation in Drosophila.

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Liotta, David; Han, Jun; Elgar, Stuart; Garvey, Clare; Han, Zhe; Taylor, Michael V

2007-08-21

Tissue development requires the controlled regulation of cell-differentiation programs. In muscle, the Mef2 transcription factor binds to and activates the expression of many genes and has a major positive role in the orchestration of differentiation. However, little is known about how Mef2 activity is regulated in vivo during development. Here, we characterize a gene, Holes in muscle (Him), which our results indicate is part of this control in Drosophila. Him expression rapidly declines as embryonic muscle differentiates, and consistent with this, Him overexpression inhibits muscle differentiation. This inhibitory effect is suppressed by mef2, implicating Him in the mef2 pathway. We then found that Him downregulates the transcriptional activity of Mef2 in both cell culture and in vivo. Furthermore, Him protein binds Groucho, a conserved, transcriptional corepressor, through a WRPW motif and requires this motif and groucho function to inhibit both muscle differentiation and Mef2 activity during development. Together, our results identify a mechanism that can inhibit muscle differentiation in vivo. We conclude that a balance of positive and negative inputs, including Mef2, Him, and Groucho, controls muscle differentiation during Drosophila development and suggest that one outcome is to hold developing muscle cells in a state with differentiation genes poised to be expressed.

Adaptation of rat jaw muscle fibers in postnatal development with a different food consistency: an immunohistochemical and electromyographic study.

Science.gov (United States)

Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Kinouchi, Nao; Kawakami, Emi; Tanne, Kazuo; Langenbach, Geerling E J; Tanaka, Eiji

2010-06-01

The development of the craniofacial system occurs, among other reasons, as a response to functional needs. In particular, the deficiency of the proper masticatory stimulus affects the growth. The purpose of this study was to relate alterations of muscle activity during postnatal development to adaptational changes in the muscle fibers. Fourteen 21-day-old Wistar strain male rats were randomly divided into two groups and fed on either a solid (hard-diet group) or a powder (soft-diet group) diet for 63 days. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time), the total burst number and their average length exceeding specified levels of the peak activity (5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of fibers by means of immunohistochemical staining and their cross-sectional area was measured. All muscle fibers were identified as slow type I and fast type IIA, IIX or IIB (respectively, with increasing twitch contraction speed and fatigability). At lower activity levels (exceeding 5% of the peak activity), the duty time of the anterior belly of the digastric muscle was significantly higher in the soft-diet group than in the hard-diet group (P fast transition of muscle fiber was shown in only the superficial masseter muscle. Therefore, the reduction in the amount of powerful muscle contractions could be important for the slow-to-fast transition of the myosin heavy chain isoform in muscle fibers.

Aerobic metabolism on muscle contraction in porcine gastric smooth muscle.

Science.gov (United States)

Kanda, Hidenori; Kaneda, Takeharu; Nagai, Yuta; Urakawa, Norimoto; Shimizu, Kazumasa

2018-05-18

Exposure to chronic hypoxic conditions causes various gastric diseases, including gastric ulcers. It has been suggested that gastric smooth muscle contraction is associated with aerobic metabolism. However, there are no reports on the association between gastric smooth muscle contraction and aerobic metabolism, and we have investigated this association in the present study. High K + - and carbachol (CCh)-induced muscle contractions involved increasing O 2 consumption. Aeration with N 2 (hypoxia) and NaCN significantly decreased high K + - and CCh-induced muscle contraction and O 2 consumption. In addition, hypoxia and NaCN significantly decreased creatine phosphate (PCr) contents in the presence of high K + . Moreover, decrease in CCh-induced contraction and O 2 consumption was greater than that of high K + . Our results suggest that hypoxia and NaCN inhibit high K + - and CCh-induced contractions in gastric fundus smooth muscles by decreasing O 2 consumption and intracellular PCr content. However, the inhibition of CCh-induced muscle contraction was greater than that of high K + -induced muscle contraction.

Characterisation, Modelling, and Development of the Reactive Peano Muscle

NARCIS (Netherlands)

Veale, A.J.

2017-01-01

Wearable robots for effective healthcare and morphing aerofoils for efficient transport can benefit enormously from actuators with muscle-like properties. These properties can make actuators inherently adaptive, productive, unobtrusive, and controllable. Motivated by the usefulness of muscle-like

NMR imaging of the anal levator and sphincter muscles in anorectal malformations

International Nuclear Information System (INIS)

Aoyagi, Hiroshi; Takahashi, Hideyo; Maie, Masahiko; Ohnuma, Naomi; Etoh, Takao; Iwai, Jun

1986-01-01

Magnetic resonance imaging (MRI) of the anal levater and sphincter muscles was obtained on 4 normal volunteers and 11 patients with postoperative anorectal malformations (including 8 supra-levator type and 3 low type). Balloon catheter were inserted into the rectum and marked it as the center of a anal canal. Four normal subjects revealed the levater and sphincter muscles were thick and well developed in all sections (Sagittal, Transevse, Coronal). In most of the supra-levator type of anorectal malformations, thin levator and sphincter muscles were observed by Sagittal and Coronal scans. Transeverse scan revealed that the neorectum was not effectively pull-throughed into the puborectal muscle in one patient. Coronal scan showed the dameged external sphincter muscle. In three low types of anorectal malformations, the levator and the sphincter muscles were all well developed, but in one patient the external sphincter muscle existed at the posterior part of the anal canal. These observations were usefull in managing the postoperative care of anorectal malformations. (author)

Quantitative phosphoproteomic analysis of porcine muscle within 24 h postmortem.

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Huang, Honggang; Larsen, Martin R; Palmisano, Giuseppe; Dai, Jie; Lametsch, René

2014-06-25

Protein phosphorylation can regulate most of the important processes in muscle, such as metabolism and contraction. The postmortem (PM) metabolism and rigor mortis have essential effects on meat quality. In order to identify and characterize the protein phosphorylation events involved in meat quality development, a quantitative mass spectrometry-based phosphoproteomic study was performed to analyze the porcine muscle within 24h PM using dimethyl labeling combined with the TiSH phosphopeptide enrichment strategy. In total 305 unique proteins were identified, including 160 phosphoproteins with 784 phosphorylation sites. Among these, 184 phosphorylation sites on 93 proteins had their phosphorylation levels significantly changed. The proteins involved in glucose metabolism and muscle contraction were the two largest clusters of phosphoproteins with significantly changed phosphorylation levels in muscle within 24 h PM. The high phosphorylation level of heat shock proteins (HSPs) in early PM may be an adaptive response to slaughter stress and protect muscle cell from apoptosis, as observed in the serine 84 of HSP27. This work indicated that PM muscle proteins underwent significant changes at the phosphorylation level but were relatively stable at the total protein level, suggesting that protein phosphorylation may have important roles in meat quality development through the regulation of proteins involved in glucose metabolism and muscle contraction, thereby affecting glycolysis and rigor mortis development in PM muscle. The manuscript describes the characterization of postmortem (PM) porcine muscle within 24 h postmortem from the perspective of protein phosphorylation using advanced phosphoproteomic techniques. In the study, the authors employed the dimethyl labeling combined with the TiSH phosphopeptide enrichment and LC-MS/MS strategy. This was the first high-throughput quantitative phosphoproteomic study in PM muscle of farm animals. In the work, both the proteome

The adipokine leptin increases skeletal muscle mass and significantly alters skeletal muscle miRNA expression profile in aged mice

International Nuclear Information System (INIS)

Hamrick, Mark W.; Herberg, Samuel; Arounleut, Phonepasong; He, Hong-Zhi; Shiver, Austin; Qi, Rui-Qun; Zhou, Li; Isales, Carlos M.

2010-01-01

Research highlights: → Aging is associated with muscle atrophy and loss of muscle mass, known as the sarcopenia of aging. → We demonstrate that age-related muscle atrophy is associated with marked changes in miRNA expression in muscle. → Treating aged mice with the adipokine leptin significantly increased muscle mass and the expression of miRNAs involved in muscle repair. → Recombinant leptin therapy may therefore be a novel approach for treating age-related muscle atrophy. -- Abstract: Age-associated loss of muscle mass, or sarcopenia, contributes directly to frailty and an increased risk of falls and fractures among the elderly. Aged mice and elderly adults both show decreased muscle mass as well as relatively low levels of the fat-derived hormone leptin. Here we demonstrate that loss of muscle mass and myofiber size with aging in mice is associated with significant changes in the expression of specific miRNAs. Aging altered the expression of 57 miRNAs in mouse skeletal muscle, and many of these miRNAs are now reported to be associated specifically with age-related muscle atrophy. These include miR-221, previously identified in studies of myogenesis and muscle development as playing a role in the proliferation and terminal differentiation of myogenic precursors. We also treated aged mice with recombinant leptin, to determine whether leptin therapy could improve muscle mass and alter the miRNA expression profile of aging skeletal muscle. Leptin treatment significantly increased hindlimb muscle mass and extensor digitorum longus fiber size in aged mice. Furthermore, the expression of 37 miRNAs was altered in muscles of leptin-treated mice. In particular, leptin treatment increased the expression of miR-31 and miR-223, miRNAs known to be elevated during muscle regeneration and repair. These findings suggest that aging in skeletal muscle is associated with marked changes in the expression of specific miRNAs, and that nutrient-related hormones such as leptin

The adipokine leptin increases skeletal muscle mass and significantly alters skeletal muscle miRNA expression profile in aged mice

Energy Technology Data Exchange (ETDEWEB)

Hamrick, Mark W., E-mail: mhamrick@mail.mcg.edu [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Herberg, Samuel; Arounleut, Phonepasong [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); He, Hong-Zhi [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Shiver, Austin [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Qi, Rui-Qun [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Zhou, Li [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Department of Internal Medicine, Henry Ford Health System, Detroit, MI (United States); Isales, Carlos M. [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); others, and

2010-09-24

Research highlights: {yields} Aging is associated with muscle atrophy and loss of muscle mass, known as the sarcopenia of aging. {yields} We demonstrate that age-related muscle atrophy is associated with marked changes in miRNA expression in muscle. {yields} Treating aged mice with the adipokine leptin significantly increased muscle mass and the expression of miRNAs involved in muscle repair. {yields} Recombinant leptin therapy may therefore be a novel approach for treating age-related muscle atrophy. -- Abstract: Age-associated loss of muscle mass, or sarcopenia, contributes directly to frailty and an increased risk of falls and fractures among the elderly. Aged mice and elderly adults both show decreased muscle mass as well as relatively low levels of the fat-derived hormone leptin. Here we demonstrate that loss of muscle mass and myofiber size with aging in mice is associated with significant changes in the expression of specific miRNAs. Aging altered the expression of 57 miRNAs in mouse skeletal muscle, and many of these miRNAs are now reported to be associated specifically with age-related muscle atrophy. These include miR-221, previously identified in studies of myogenesis and muscle development as playing a role in the proliferation and terminal differentiation of myogenic precursors. We also treated aged mice with recombinant leptin, to determine whether leptin therapy could improve muscle mass and alter the miRNA expression profile of aging skeletal muscle. Leptin treatment significantly increased hindlimb muscle mass and extensor digitorum longus fiber size in aged mice. Furthermore, the expression of 37 miRNAs was altered in muscles of leptin-treated mice. In particular, leptin treatment increased the expression of miR-31 and miR-223, miRNAs known to be elevated during muscle regeneration and repair. These findings suggest that aging in skeletal muscle is associated with marked changes in the expression of specific miRNAs, and that nutrient

MicroRNA in Skeletal Muscle: Its Crucial Roles in Signal Proteins, Mus cle Fiber Type, and Muscle Protein Synthesis.

Science.gov (United States)

Zhang, Jing; Liu, Yu Lan

2017-01-01

Pork is one of the most economical sources of animal protein for human consumption. Meat quality is an important economic trait for the swine industry, which is primarily determined by prenatal muscle development and postnatal growth. Identification of the molecular mechanisms underlying skeletal muscle development is a key priority. MicroRNAs (miRNAs) are a class of small noncoding RNAs that have emerged as key regulators of skeletal muscle development. A number of muscle-related miRNAs have been identified by functional gain and loss experiments in mouse model. However, determining miRNA-mRNA interactions involved in pig skeletal muscle still remains a significant challenge. For a comprehensive understanding of miRNA-mediated mechanisms underlying muscle development, miRNAome analyses of pig skeletal muscle have been performed by deep sequencing. Additionally, porcine miRNA single nucleotide polymorphisms have been implicated in muscle fiber types and meat quality. The present review provides an overview of current knowledge on recently identified miRNAs involved in myogenesis, muscle fiber type and muscle protein metabolism. Undoubtedly, further systematic understanding of the functions of miRNAs in pig skeletal muscle development will be helpful to expand the knowledge of basic skeletal muscle biology and be beneficial for the genetic improvement of meat quality traits. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

MR imaging of muscle diseases

International Nuclear Information System (INIS)

Kaiser, W.A.; Zeitler, E.; Schalke, B.C.G.

1986-01-01

Because of high soft-tissue contrast, MR imaging is especially suitable for the investigation of muscle diseases. Between March 1984 and March 1986, 76 patients with different types of muscle diseases were examined using a 1-T superconductive magnet (Siemens Magnetom). Studied were 14 patients with progressive muscular dystrophy (including carriers), 32 patients with myositis, four patients with myotonic dystrophy, six patients with spinal muscular atrophy, and 20 patients with other muscle diseases, including metabolic disorders. MR imaging showed typical signal patterns in affected muscle groups. These patterns can be used in the differential diagnosis, in biopsy planning, or in evaluation of response to therapy. The T1/T2 ratio especially seems to indicate very early stages of muscle disease

Anatomy and biomechanics of the back muscles in the lumbar spine with reference to biomechanical modeling

DEFF Research Database (Denmark)

Hansen, L.; Zee, M. de; Rasmussen, J.

2006-01-01

This article describes the development of a musculoskeletal model of the human lumbar spine with focus on back muscles. It includes data from literature in a structured form.......This article describes the development of a musculoskeletal model of the human lumbar spine with focus on back muscles. It includes data from literature in a structured form....

The Role of Muscle Mass, Muscle Quality, and Body Composition in Risk for the Metabolic Syndrome and Functional Decline in Older Adults: Topical Collection on Nutrition, Obesity, and Diabetes

NARCIS (Netherlands)

R.T. Mankowski (Robert T.); S.D. Anton (Stephen D.); M. Aubertin-Leheudre (Mylene)

2015-01-01

textabstractAbstract Age-related body composition changes include both loss of muscle mass (sarcopenia) and increase in fat mass, which jointly contribute to a decline in metabolic functions. Muscle quality is positively related to functional capacity and a lower risk for the development of the

The effects of Capn1 gene inactivation on skeletal muscle growth, development, and atrophy, and the compensatory role of other proteolytic systems.

Science.gov (United States)

Kemp, C M; Oliver, W T; Wheeler, T L; Chishti, A H; Koohmaraie, M

2013-07-01

Myofibrillar protein turnover is a key component of muscle growth and degeneration, requiring proteolytic enzymes to degrade the skeletal muscle proteins. The objective of this study was to investigate the role of the calpain proteolytic system in muscle growth development using μ-calpain knockout (KO) mice in comparison with control wild-type (WT) mice, and evaluate the subsequent effects of silencing this gene on other proteolytic systems. No differences in muscle development between genotypes were observed during the early stages of growth due to the up regulation of other proteolytic systems. The KO mice showed significantly greater m-calpain protein abundance (P proteolytic systems to ensure muscle protein homeostasis in vivo. Furthermore, these data contribute to the existing evidence of the importance of the calpain system's involvement in muscle growth, development, and atrophy. Collectively, these data suggest that there are opportunities to target the calpain system to promote the growth and/or restoration of skeletal muscle mass.

Targeted massively parallel sequencing and histological assessment of skeletal muscles for the molecular diagnosis of inherited muscle disorders.

Science.gov (United States)

Nishikawa, Atsuko; Mitsuhashi, Satomi; Miyata, Naomasa; Nishino, Ichizo

2017-02-01

Inherited skeletal muscle diseases are genetically heterogeneous diseases caused by mutations in more than 150 genes. This has made it challenging to establish a high-throughput screening method for identifying causative gene mutations in clinical practice. In the present study, we developed a useful method for screening gene mutations associated with the pathogenesis of skeletal muscle diseases. We established four target gene panels, each covering all exonic and flanking regions of genes involved in the pathogenesis of the following muscle diseases: (1) muscular dystrophy (MD), (2) congenital myopathy/congenital myasthenic syndrome, (3) metabolic myopathy and (4) myopathy with protein aggregations/rimmed vacuoles. We assigned one panel to each patient based on the results of clinical and histological analyses of biopsied muscle samples and performed high-throughput sequencing by using Ion PGM next-generation sequencer. We also performed protein analysis to confirm defective proteins in patients with major muscular dystrophies. Further, we performed muscle-derived cDNA analysis to identify splice-site mutations. We identified possible causative gene mutations in 33% of patients (62/188) included in this study. Our results showed that the MD panel was the most useful, with a diagnostic rate of 46.2%. Thus, we developed a high-throughput sequencing technique for diagnosing inherited muscle diseases. The use of this technique along with histological and protein analyses may be useful and cost-effective for screening mutations in patients with inherited skeletal muscle diseases. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Genomic signatures characterize leukocyte infiltration in myositis muscles

Science.gov (United States)

2012-01-01

Background Leukocyte infiltration plays an important role in the pathogenesis and progression of myositis, and is highly associated with disease severity. Currently, there is a lack of: efficacious therapies for myositis; understanding of the molecular features important for disease pathogenesis; and potential molecular biomarkers for characterizing inflammatory myopathies to aid in clinical development. Methods In this study, we developed a simple model and predicted that 1) leukocyte-specific transcripts (including both protein-coding transcripts and microRNAs) should be coherently overexpressed in myositis muscle and 2) the level of over-expression of these transcripts should be correlated with leukocyte infiltration. We applied this model to assess immune cell infiltration in myositis by examining mRNA and microRNA (miRNA) expression profiles in muscle biopsies from 31 myositis patients and 5 normal controls. Results Several gene signatures, including a leukocyte index, type 1 interferon (IFN), MHC class I, and immunoglobulin signature, were developed to characterize myositis patients at the molecular level. The leukocyte index, consisting of genes predominantly associated with immune function, displayed strong concordance with pathological assessment of immune cell infiltration. This leukocyte index was subsequently utilized to differentiate transcriptional changes due to leukocyte infiltration from other alterations in myositis muscle. Results from this differentiation revealed biologically relevant differences in the relationship between the type 1 IFN pathway, miR-146a, and leukocyte infiltration within various myositis subtypes. Conclusions Results indicate that a likely interaction between miR-146a expression and the type 1 IFN pathway is confounded by the level of leukocyte infiltration into muscle tissue. Although the role of miR-146a in myositis remains uncertain, our results highlight the potential benefit of deconvoluting the source of

Bio-inspired Hybrid Carbon Nanotube Muscles

Science.gov (United States)

Kim, Tae Hyeob; Kwon, Cheong Hoon; Lee, Changsun; An, Jieun; Phuong, Tam Thi Thanh; Park, Sun Hwa; Lima, Márcio D.; Baughman, Ray H.; Kang, Tong Mook; Kim, Seon Jeong

2016-05-01

There has been continuous progress in the development for biomedical engineering systems of hybrid muscle generated by combining skeletal muscle and artificial structure. The main factor affecting the actuation performance of hybrid muscle relies on the compatibility between living cells and their muscle scaffolds during cell culture. Here, we developed a hybrid muscle powered by C2C12 skeletal muscle cells based on the functionalized multi-walled carbon nanotubes (MWCNT) sheets coated with poly(3,4-ethylenedioxythiophene) (PEDOT) to achieve biomimetic actuation. This hydrophilic hybrid muscle is physically durable in solution and responds to electric field stimulation with flexible movement. Furthermore, the biomimetic actuation when controlled by electric field stimulation results in movement similar to that of the hornworm by patterned cell culture method. The contraction and relaxation behavior of the PEDOT/MWCNT-based hybrid muscle is similar to that of the single myotube movement, but has faster relaxation kinetics because of the shape-maintenance properties of the freestanding PEDOT/MWCNT sheets in solution. Our development provides the potential possibility for substantial innovation in the next generation of cell-based biohybrid microsystems.

A three-dimensional muscle activity imaging technique for assessing pelvic muscle function

Science.gov (United States)

Zhang, Yingchun; Wang, Dan; Timm, Gerald W.

2010-11-01

A novel multi-channel surface electromyography (EMG)-based three-dimensional muscle activity imaging (MAI) technique has been developed by combining the bioelectrical source reconstruction approach and subject-specific finite element modeling approach. Internal muscle activities are modeled by a current density distribution and estimated from the intra-vaginal surface EMG signals with the aid of a weighted minimum norm estimation algorithm. The MAI technique was employed to minimally invasively reconstruct electrical activity in the pelvic floor muscles and urethral sphincter from multi-channel intra-vaginal surface EMG recordings. A series of computer simulations were conducted to evaluate the performance of the present MAI technique. With appropriate numerical modeling and inverse estimation techniques, we have demonstrated the capability of the MAI technique to accurately reconstruct internal muscle activities from surface EMG recordings. This MAI technique combined with traditional EMG signal analysis techniques is being used to study etiologic factors associated with stress urinary incontinence in women by correlating functional status of muscles characterized from the intra-vaginal surface EMG measurements with the specific pelvic muscle groups that generated these signals. The developed MAI technique described herein holds promise for eliminating the need to place needle electrodes into muscles to obtain accurate EMG recordings in some clinical applications.

Heterogeneity among muscle precursor cells in adult skeletal muscles with differing regenerative capacities.

Science.gov (United States)

Pavlath, G K; Thaloor, D; Rando, T A; Cheong, M; English, A W; Zheng, B

1998-08-01

Skeletal muscle has a remarkable capacity to regenerate after injury, although studies of muscle regeneration have heretofore been limited almost exclusively to limb musculature. Muscle precursor cells in skeletal muscle are responsible for the repair of damaged muscle. Heterogeneity exists in the growth and differentiation properties of muscle precursor cell (myoblast) populations throughout limb development but whether the muscle precursor cells differ among adult skeletal muscles is unknown. Such heterogeneity among myoblasts in the adult may give rise to skeletal muscles with different regenerative capacities. Here we compare the regenerative response of a masticatory muscle, the masseter, to that of limb muscles. After exogenous trauma (freeze or crush injuries), masseter muscle regenerated much less effectively than limb muscle. In limb muscle, normal architecture was restored 12 days after injury, whereas in masseter muscle, minimal regeneration occurred during the same time period. Indeed, at late time points, masseter muscles exhibited increased fibrous connective tissue in the region of damage, evidence of ineffective muscle regeneration. Similarly, in response to endogenous muscle injury due to a muscular dystrophy, widespread evidence of impaired regeneration was present in masseter muscle but not in limb muscle. To explore the cellular basis of these different regenerative capacities, we analyzed the myoblast populations of limb and masseter muscles both in vivo and in vitro. From in vivo analyses, the number of myoblasts in regenerating muscle was less in masseter compared with limb muscle. Assessment of population growth in vitro indicated that masseter myoblasts grow more slowly than limb myoblasts under identical conditions. We conclude that the impaired regeneration in masseter muscles is due to differences in the intrinsic myoblast populations compared to limb muscles.

The role of mitochondrial DNA damage at skeletal muscle oxidative stress on the development of type 2 diabetes.

Science.gov (United States)

Dos Santos, Julia Matzenbacher; de Oliveira, Denise Silva; Moreli, Marcos Lazaro; Benite-Ribeiro, Sandra Aparecida

2018-04-20

Reduced cellular response to insulin in skeletal muscle is one of the major components of the development of type 2 diabetes (T2D). Mitochondrial dysfunction involves in the accumulation of toxic reactive oxygen species (ROS) that leads to insulin resistance. The aim of this study was to verify the involvement of mitochondrial DNA damage at ROS generation in skeletal muscle during development of T2D. Wistar rats were fed a diet containing 60% fat over 8 weeks and at day 14 a single injection of STZ (25 mg/kg) was administered (T2D-induced). Control rats received standard food and an injection of citrate buffer. Blood and soleus muscle were collected. Abdominal fat was quantified as well as glucose, triglyceride, LDL, HDL, and total cholesterol in plasma and mtDNA copy number, cytochrome b (cytb) mRNA, 8-hydroxyguanosine, and 8-isoprostane (a marker of ROS) in soleus muscle. T2D-induced animal presented similar characteristics to humans that develop T2D such as changes in blood glucose, abdominal fat, LDL, HDL and cholesterol total. In soleus muscle 8-isoprostane, mtDNA copy number and 8-hydroxyguanosine were increased, while cytb mRNA was decreased in T2D. Our results suggest that in the development of T2D, when risks factors of T2D are present, intracellular oxidative stress increases in skeletal muscle and is associated with a decrease in cytb transcription. To overcome this process mtDNA increased but due to the proximity of ROS generation, mtDNA remains damaged by oxidation leading to an increase in ROS in a vicious cycle accounting to the development of insulin resistance and further T2D.

Respiratory muscle stretch gymnastics in patients with post coronary artery bypass grafting pain : Impact on respiratory muscle function, activity, mood and exercise capacity

OpenAIRE

會田, 信子; 渋谷, 優子; 吉野, 克樹; Komoda, Masaji; 井上, 智子

2002-01-01

A new rehabilitation (New-RH) program including respiratory muscle stretch gymnastics (RMSG) was developed to alleviate post-coronary artery bypass grafting pain (PCP). Effects on respiratory muscle function, pain, activities of daily living (ADL), mood and exercise capacity were investigated. Subjects were 16 consecutive patients undergoing median full sternotomy coronary artery bypass grafting (CABG), and were randomly divided into equal New-RH (S-group) and conventional therapy (C-group) g...

Could a functional artificial skeletal muscle be useful in muscle wasting?

Science.gov (United States)

Fuoco, Claudia; Cannata, Stefano; Gargioli, Cesare

2016-05-01

Regardless of the underlying cause, skeletal muscle wasting is detrimental for a person's life quality, leading to impaired strength, locomotion, and physiological activity. Here, we propose a series of studies presenting tissue engineering-based approaches to reconstruct artificial muscle in vitro and in vivo. Skeletal muscle tissue engineering is attracting more and more attention from scientists, clinicians, patients, and media, thanks to the promising results obtained in the last decade with animal models of muscle wasting. The use of novel and refined biomimetic scaffolds mimicking three-dimensional muscle environment, thus supporting cell survival and differentiation, in combination with well characterized myogenic stem/progenitor cells, revealed the noteworthy potential of these technologies for creating artificial skeletal muscle tissue. In vitro, the production of three-dimensional muscle structures offer the possibility to generate a drug-screening platform for patient-specific pharmacological treatment, opening new frontiers in the development of new compounds with specific therapeutic actions. In vivo, three-dimensional artificial muscle biomimetic constructs offer the possibility to replace, in part or entirely, wasted muscle by means of straight reconstruction and/or by enhancing endogenous regeneration. Reports of tissue engineering approaches for artificial muscle building appeared in large numbers in the specialized press lately, advocating the suitability of this technology for human application upon scaling up and a near future applicability for medical care of muscle wasting. http://links.lww.com/COCN/A9

Reduced serum myostatin concentrations associated with genetic muscle disease progression.

Science.gov (United States)

Burch, Peter M; Pogoryelova, Oksana; Palandra, Joe; Goldstein, Richard; Bennett, Donald; Fitz, Lori; Guglieri, Michela; Bettolo, Chiara Marini; Straub, Volker; Evangelista, Teresinha; Neubert, Hendrik; Lochmüller, Hanns; Morris, Carl

2017-03-01

Myostatin is a highly conserved protein secreted primarily from skeletal muscle that can potently suppress muscle growth. This ability to regulate skeletal muscle mass has sparked intense interest in the development of anti-myostatin therapies for a wide array of muscle disorders including sarcopenia, cachexia and genetic neuromuscular diseases. While a number of studies have examined the circulating myostatin concentrations in healthy and sarcopenic populations, very little data are available from inherited muscle disease patients. Here, we have measured the myostatin concentration in serum from seven genetic neuromuscular disorder patient populations using immunoaffinity LC-MS/MS. Average serum concentrations of myostatin in all seven muscle disease patient groups were significantly less than those measured in healthy controls. Furthermore, circulating myostatin concentrations correlated with clinical measures of disease progression for five of the muscle disease patient populations. These findings greatly expand the understanding of myostatin in neuromuscular disease and suggest its potential utility as a biomarker of disease progression.

The role of the renin-angiotensin system in the development of insulin resistance in skeletal muscle.

Science.gov (United States)

Henriksen, Erik J; Prasannarong, Mujalin

2013-09-25

The canonical renin-angiotensin system (RAS) involves the initial action of renin to cleave angiotensinogen to angiotensin I (ANG I), which is then converted to ANG II by the angiotensin converting enzyme (ACE). ANG II plays a critical role in numerous physiological functions, and RAS overactivity underlies many conditions of cardiovascular dysregulation. In addition, ANG II, by acting on both endothelial and myocellular AT1 receptors, can induce insulin resistance by increasing cellular oxidative stress, leading to impaired insulin signaling and insulin-stimulated glucose transport activity. This insulin resistance associated with RAS overactivity, when coupled with progressive ß-cell dysfunction, eventually leads to the development of type 2 diabetes. Interventions that target RAS overactivity, including ACE inhibitors, ANG II receptor blockers, and, most recently, renin inhibitors, are effective both in reducing hypertension and in improving whole-body and skeletal muscle insulin action, due at least in part to enhanced Akt-dependent insulin signaling and insulin-dependent glucose transport activity. ANG-(1-7), which is produced from ANG II by the action of ACE2 and acts via Mas receptors, can counterbalance the deleterious actions of the ACE/ANG II/AT1 receptor axis on the insulin-dependent glucose transport system in skeletal muscle. This beneficial effect of the ACE2/ANG-(1-7)/Mas receptor axis appears to depend on the activation of Akt. Collectively, these findings underscore the importance of RAS overactivity in the multifactorial etiology of insulin resistance in skeletal muscle, and provide support for interventions that target the RAS to ameliorate both cardiovascular dysfunctions and insulin resistance in skeletal muscle tissue. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Sepsis and development impede muscle protein synthesis in neonatal pigs by different ribosomal mechanisms

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In muscle, sepsis reduces protein synthesis (MPS) by restraining translation in neonates and adults. Even though protein accretion decreases with development as neonatal MPS rapidly declines by maturation, the changes imposed by development on the sepsis-associated decrease in MPS have not been desc...

Intraoperative length and tension curves of human eye muscles. Including stiffness in passive horizontal eye movement in awake volunteers

NARCIS (Netherlands)

H.J. Simonsz (Huib); G.H. Kolling (Gerold); H. Kaufmann (Herbert); B. van Dijk (Bob)

1986-01-01

textabstractIntraoperative continuous-registration length and tension curves of attached and detached eye muscles were made in 18 strabismic patients under general anesthesia. For relaxed eye muscles, we found an exponential relation between length and tension. An increased stiffness was quantified

Mathematical models of human paralyzed muscle after long-term training.

Science.gov (United States)

Law, L A Frey; Shields, R K

2007-01-01

Spinal cord injury (SCI) results in major musculoskeletal adaptations, including muscle atrophy, faster contractile properties, increased fatigability, and bone loss. The use of functional electrical stimulation (FES) provides a method to prevent paralyzed muscle adaptations in order to sustain force-generating capacity. Mathematical muscle models may be able to predict optimal activation strategies during FES, however muscle properties further adapt with long-term training. The purpose of this study was to compare the accuracy of three muscle models, one linear and two nonlinear, for predicting paralyzed soleus muscle force after exposure to long-term FES training. Further, we contrasted the findings between the trained and untrained limbs. The three models' parameters were best fit to a single force train in the trained soleus muscle (N=4). Nine additional force trains (test trains) were predicted for each subject using the developed models. Model errors between predicted and experimental force trains were determined, including specific muscle force properties. The mean overall error was greatest for the linear model (15.8%) and least for the nonlinear Hill Huxley type model (7.8%). No significant error differences were observed between the trained versus untrained limbs, although model parameter values were significantly altered with training. This study confirmed that nonlinear models most accurately predict both trained and untrained paralyzed muscle force properties. Moreover, the optimized model parameter values were responsive to the relative physiological state of the paralyzed muscle (trained versus untrained). These findings are relevant for the design and control of neuro-prosthetic devices for those with SCI.

Effect of experimental hyperthyroidism on protein turnover in skeletal and cardiac muscle.

Science.gov (United States)

Carter, W J; Van Der Weijden Benjamin, W S; Faas, F H

1980-10-01

Since experimental hyperthyroidism reduces skeletal muscle mass while simultaneously increasing cardiac muscle mass, the effect of hyperthyroidism on muscle protein degradation was compared in skeletal and cardiac muscle. Pulse-labeling studies using (3H) leucine and (14C) carboxyl labeled aspartate and glutamate were carried out. Hyperthyroidism caused a 25%-29% increase in protein breakdown in both sarcoplasmic and myofibrillar fractions of skeletal muscle. Increased muscle protein degradation may be a major factor in the development of skeletal muscle wasting and weakness in hyperthyroidism. In contrast, protein breakdown appeared to be reduced 22% in the sarcoplasmic fraction of hyperthyroid heart muscle and was unchanged in the myofibrillar fraction. Possible reasons for the contrasting effects of hyperthyroidism on skeletal and cardiac muscle include increased sensitivity of the hyperthyroid heart to catecholamines, increased cardiac work caused by the hemodynamic effects of hyperthyroidism, and a different direct effect of thyroid hormone at the nuclear level in cardiac as opposed to skeletal muscle.

Generation of skeletal muscle from transplanted embryonic stem cells in dystrophic mice

International Nuclear Information System (INIS)

Bhagavati, Satyakam; Xu Weimin

2005-01-01

Embryonic stem (ES) cells have great therapeutic potential because of their capacity to proliferate extensively and to form any fully differentiated cell of the body, including skeletal muscle cells. Successful generation of skeletal muscle in vivo, however, requires selective induction of the skeletal muscle lineage in cultures of ES cells and following transplantation, integration of appropriately differentiated skeletal muscle cells with recipient muscle. Duchenne muscular dystrophy (DMD), a severe progressive muscle wasting disease due to a mutation in the dystrophin gene and the mdx mouse, an animal model for DMD, are characterized by the absence of the muscle membrane associated protein, dystrophin. Here, we show that co-culturing mouse ES cells with a preparation from mouse muscle enriched for myogenic stem and precursor cells, followed by injection into mdx mice, results occasionally in the formation of normal, vascularized skeletal muscle derived from the transplanted ES cells. Study of this phenomenon should provide valuable insights into skeletal muscle development in vivo from transplanted ES cells

MicroRNA-128 targets myostatin at coding domain sequence to regulate myoblasts in skeletal muscle development.

Science.gov (United States)

Shi, Lei; Zhou, Bo; Li, Pinghua; Schinckel, Allan P; Liang, Tingting; Wang, Han; Li, Huizhi; Fu, Lingling; Chu, Qingpo; Huang, Ruihua

2015-09-01

MicroRNAs (miRNAs or miRs) play a critical role in skeletal muscle development. In a previous study we observed that miR-128 was highly expressed in skeletal muscle. However, its function in regulating skeletal muscle development is not clear. Our hypothesis was that miR-128 is involved in the regulation of the proliferation and differentiation of skeletal myoblasts. In this study, through bioinformatics analyses, we demonstrate that miR-128 specifically targeted mRNA of myostatin (MSTN), a critical inhibitor of skeletal myogenesis, at coding domain sequence (CDS) region, resulting in down-regulating of myostatin post-transcription. Overexpression of miR-128 inhibited proliferation of mouse C2C12 myoblast cells but promoted myotube formation; whereas knockdown of miR-128 had completely opposite effects. In addition, ectopic miR-128 regulated the expression of myogenic factor 5 (Myf5), myogenin (MyoG), paired box (Pax) 3 and 7. Furthermore, an inverse relationship was found between the expression of miR-128 and MSTN protein expression in vivo and in vitro. Taken together, these results reveal that there is a novel pathway in skeletal muscle development in which miR-128 regulates myostatin at CDS region to inhibit proliferation but promote differentiation of myoblast cells. Copyright © 2015 Elsevier Inc. All rights reserved.

Regulation of myostatin expression is associated with growth and muscle development in commercial broiler and DMC muscle

NARCIS (Netherlands)

Dou, Tengfei; Li, Zhengtian; Wang, Kun; Liu, Lixian; Rong, Hua; Xu, Zhiqiang; Huang, Ying; Gu, Dahai; Chen, Xiaobo; Hu, Wenyuan; Zhang, Jiarong; Zhao, Sumei; Jois, Markandeya; Li, Qihua; Ge, Changrong; Pas, te Marinus F.W.; Jia, Junjing

2018-01-01

Myostatin is a negative regulator of skeletal muscle growth. Muscle tissue is the largest tissue in the body and influences body growth. Commercial Avian broiler chickens are selected for high growth rate and muscularity. Daweishan mini chickens are a slow growing small-sized chicken breed. We

Diseases and disorders of muscle.

Science.gov (United States)

Pearson, A M; Young, R B

1993-01-01

Muscle may suffer from a number of diseases or disorders, some being fatal to humans and animals. Their management or treatment depends on correct diagnosis. Although no single method may be used to identify all diseases, recognition depends on the following diagnostic procedures: (1) history and clinical examination, (2) blood biochemistry, (3) electromyography, (4) muscle biopsy, (5) nuclear magnetic resonance, (6) measurement of muscle cross-sectional area, (7) tests of muscle function, (8) provocation tests, and (9) studies on protein turnover. One or all of these procedures may prove helpful in diagnosis, but even then identification of the disorder may not be possible. Nevertheless, each of these procedures can provide useful information. Among the most common diseases in muscle are the muscular dystrophies, in which the newly identified muscle protein dystrophin is either absent or present at less than normal amounts in both Duchenne and Becker's muscular dystrophy. Although the identification of dystrophin represents a major breakthrough, treatment has not progressed to the experimental stage. Other major diseases of muscle include the inflammatory myopathies and neuropathies. Atrophy and hypertrophy of muscle and the relationship of aging, exercise, and fatigue all add to our understanding of the behavior of normal and abnormal muscle. Some other interesting related diseases and disorders of muscle include myasthenia gravis, muscular dysgenesis, and myclonus. Disorders of energy metabolism include those caused by abnormal glycolysis (Von Gierke's, Pompe's, Cori-Forbes, Andersen's, McArdle's, Hers', and Tauri's diseases) and by the acquired diseases of glycolysis (disorders of mitochondrial oxidation). Still other diseases associated with abnormal energy metabolism include lipid-related disorders (carnitine and carnitine palmitoyl-transferase deficiencies) and myotonic syndromes (myotonia congenita, paramyotonia congenita, hypokalemic and hyperkalemic

Injury and subsequent regeneration of muscles for activation of local innate immunity to facilitate the development and relapse of autoimmune myositis in C57BL/6 mice.

Science.gov (United States)

Kimura, Naoki; Hirata, Shinya; Miyasaka, Nobuyuki; Kawahata, Kimito; Kohsaka, Hitoshi

2015-04-01

To determine whether injury and regeneration of the skeletal muscles induce an inflammatory milieu that facilitates the development and relapse of autoimmune myositis. The quadriceps of C57BL/6 mice were injured with bupivacaine hydrochloride (BPVC) and evaluated histologically. Macrophages and regenerating myofibers in the treated muscles and differentiating C2C12 myotubes were examined for cytokine expression. Mice were immunized with C protein fragments at the base of the tail and in the right hind footpads (day 0) to evoke systemic anti-C protein immunity and to induce local myositis in the right hind limbs. The contralateral quadriceps muscles were injured with BPVC or phosphate buffered saline (PBS) on day 7 or after spontaneous regression of myositis (day 42). The quadriceps muscle in nonimmunized mice was injured with BPVC on day 7. The muscles were examined histologically 14 days after treatment. The BPVC-injured muscles had macrophage infiltration most abundantly at 3 days after the injection, with emergence of regenerating fibers from day 5. The macrophages expressed inflammatory cytokines, including tumor necrosis factor α, interleukin-1β, and CCL2. Regenerating myofibers and C2C12 myotubes also expressed the cytokines. The BPVC-injected muscles from nonimmunized mice had regenerating myofibers with resolved cell infiltration 14 days after treatment. In mice preimmunized with C protein fragments, the muscles injected with BPVC on day 7 as well as on day 42, but not those injected with PBS, had myositis accompanied by CD8+ T cell infiltration. Injury and regeneration could set up an inflammatory milieu in the muscles and facilitate the development and relapse of autoimmune myositis. Copyright © 2015 by the American College of Rheumatology.

Differentiated muscles are mandatory for gas-filling of the Drosophila airway system

Directory of Open Access Journals (Sweden)

Yiwen Wang

2015-12-01

Full Text Available At the end of development, organs acquire functionality, thereby ensuring autonomy of an organism when it separates from its mother or a protective egg. In insects, respiratory competence starts when the tracheal system fills with gas just before hatching of the juvenile animal. Cellular and molecular mechanisms of this process are not fully understood. Analyses of the phenotype of Drosophila embryos with malformed muscles revealed that they fail to gas-fill their tracheal system. Indeed, we show that major regulators of muscle formation like Lame duck and Blown fuse are important, while factors involved in the development of subsets of muscles including cardiac and visceral muscles are dispensable for this process, suggesting that somatic muscles (or parts of them are essential to enable tracheal terminal differentiation. Based on our phenotypic data, we assume that somatic muscle defect severity correlates with the penetrance of the gas-filling phenotype. This argues that a limiting molecular or mechanical muscle-borne signal tunes tracheal differentiation. We think that in analogy to the function of smooth muscles in vertebrate lungs, a balance of physical forces between muscles and the elasticity of tracheal walls may be decisive for tracheal terminal differentiation in Drosophila.

Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

Science.gov (United States)

Ianuzzo, C. D.; Chen, V.

1977-01-01

Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

Repeated Muscle Injury as a Presumptive Trigger for Chronic Masticatory Muscle Pain

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Dean Dessem

2011-01-01

Full Text Available skeletal muscles sustain a significant loss of maximal contractile force after injury, but terminally damaged fibers can eventually be replaced by the growth of new muscle (regeneration, with full restoration of contractile force over time. After a second injury, limb muscles exhibit a smaller reduction in maximal force and reduced inflammation compared with that after the initial injury (i.e., repeated bout effect. In contrast, masticatory muscles exhibit diminished regeneration and persistent fibrosis, after a single injury; following a second injury, plasma extravasation is greater than after a single injury and maximal force is decreased more than after the initial injury. Thus, masticatory muscles do not exhibit a repeated bout effect and are instead increasingly damaged by repeated injury. We propose that the impaired ability of masticatory muscles to regenerate contributes to chronic muscle pain by leading to an accumulation of tissue damage, fibrosis, and a persistent elevation and prolonged membrane translocation of nociceptive channels such as P2X3 as well as enhanced expression of neuropeptides including CGRP within primary afferent neurons. These transformations prime primary afferent neurons for enhanced responsiveness upon subsequent injury thus triggering and/or exacerbating chronic muscle pain.

MRI appearance of muscle denervation

Energy Technology Data Exchange (ETDEWEB)

Kamath, S. [University Hospital of Wales, Department of Radiology, Cardiff (United Kingdom); Venkatanarasimha, N.; Walsh, M.A.; Hughes, P.M. [Derriford Hospital, Department of Radiology, Plymouth (United Kingdom)

2008-05-15

Muscle denervation results from a variety of causes including trauma, neoplasia, neuropathies, infections, autoimmune processes and vasculitis. Traditionally, the diagnosis of muscle denervation was based on clinical examination and electromyography. Magnetic resonance imaging (MRI) offers a distinct advantage over electromyography, not only in diagnosing muscle denervation, but also in determining its aetiology. MRI demonstrates characteristic signal intensity patterns depending on the stage of muscle denervation. The acute and subacutely denervated muscle shows a high signal intensity pattern on fluid sensitive sequences and normal signal intensity on T1-weighted MRI images. In chronic denervation, muscle atrophy and fatty infiltration demonstrate high signal changes on T1-weighted sequences in association with volume loss. The purpose of this review is to summarise the MRI appearance of denervated muscle, with special emphasis on the signal intensity patterns in acute and subacute muscle denervation. (orig.)

Skeletal muscle tissue engineering: methods to form skeletal myotubes and their applications.

Science.gov (United States)

Ostrovidov, Serge; Hosseini, Vahid; Ahadian, Samad; Fujie, Toshinori; Parthiban, Selvakumar Prakash; Ramalingam, Murugan; Bae, Hojae; Kaji, Hirokazu; Khademhosseini, Ali

2014-10-01

Skeletal muscle tissue engineering (SMTE) aims to repair or regenerate defective skeletal muscle tissue lost by traumatic injury, tumor ablation, or muscular disease. However, two decades after the introduction of SMTE, the engineering of functional skeletal muscle in the laboratory still remains a great challenge, and numerous techniques for growing functional muscle tissues are constantly being developed. This article reviews the recent findings regarding the methodology and various technical aspects of SMTE, including cell alignment and differentiation. We describe the structure and organization of muscle and discuss the methods for myoblast alignment cultured in vitro. To better understand muscle formation and to enhance the engineering of skeletal muscle, we also address the molecular basics of myogenesis and discuss different methods to induce myoblast differentiation into myotubes. We then provide an overview of different coculture systems involving skeletal muscle cells, and highlight major applications of engineered skeletal muscle tissues. Finally, potential challenges and future research directions for SMTE are outlined.

Catechins activate muscle stem cells by Myf5 induction and stimulate muscle regeneration.

Science.gov (United States)

Kim, A Rum; Kim, Kyung Min; Byun, Mi Ran; Hwang, Jun-Ha; Park, Jung Il; Oh, Ho Taek; Kim, Hyo Kyeong; Jeong, Mi Gyeong; Hwang, Eun Sook; Hong, Jeong-Ho

2017-07-22

Muscle weakness is one of the most common symptoms in aged individuals and increases risk of mortality. Thus, maintenance of muscle mass is important for inhibiting aging. In this study, we investigated the effect of catechins, polyphenol compounds in green tea, on muscle regeneration. We found that (-)-epicatechin gallate (ECG) and (-)-epigallocatechin-3-gallate (EGCG) activate satellite cells by induction of Myf5 transcription factors. For satellite cell activation, Akt kinase was significantly induced after ECG treatment and ECG-induced satellite cell activation was blocked in the presence of Akt inhibitor. ECG also promotes myogenic differentiation through the induction of myogenic markers, including Myogenin and Muscle creatine kinase (MCK), in satellite and C2C12 myoblast cells. Finally, EGCG administration to mice significantly increased muscle fiber size for regeneration. Taken together, the results suggest that catechins stimulate muscle stem cell activation and differentiation for muscle regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

A Patient Developed Painful Muscle Cramps due to Overeating Mangos

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Kazuo Abe

2012-01-01

Full Text Available A 79-year-old woman had a habit to eat a mango every night before sleep and experienced muscle cramps during sleep. Her muscle cramps may be resulted from potassium overload due to overeating mangos.

Double-Acting Sleeve Muscle Actuator for Bio-Robotic Systems

Directory of Open Access Journals (Sweden)

Hao Zheng

2013-11-01

Full Text Available This paper presents a new type of muscle-like actuator, namely double-acting (DA sleeve muscle actuator, which is suitable for the actuation of biologically-inspired and biomedical robotic systems, especially those serving human-assistance purposes (prostheses, orthoses, etc.. Developed based on the traditional pneumatic muscle actuator, the new DA sleeve muscle incorporates a unique insert at the center. With the insert occupying the central portion of the internal volume, this new actuator enjoys multiple advantages relative to the traditional pneumatic muscle, including a consistent increase of force capacity over the entire range of motion, and a significant decrease of energy consumption in operation. Furthermore, the insert encompasses an additional chamber, which generates an extension force when pressurized. As such, this new actuator provides a unique bi-directional actuation capability, and, thus, has a potential to significantly simplify the design of a muscle actuator-powered robotic system. To demonstrate this new actuator concept, a prototype has been designed and fabricated, and experiments conducted on this prototype demonstrated the enhanced force capacity and the unique bi-directional actuation capability.

Double-Acting Sleeve Muscle Actuator for Bio-Robotic Systems

Science.gov (United States)

Zheng, Hao; Shen, Xiangrong

2014-01-01

This paper presents a new type of muscle-like actuator, namely double-acting (DA) sleeve muscle actuator, which is suitable for the actuation of biologically-inspired and biomedical robotic systems, especially those serving human-assistance purposes (prostheses, orthoses, etc.). Developed based on the traditional pneumatic muscle actuator, the new DA sleeve muscle incorporates a unique insert at the center. With the insert occupying the central portion of the internal volume, this new actuator enjoys multiple advantages relative to the traditional pneumatic muscle, including a consistent increase of force capacity over the entire range of motion, and a significant decrease of energy consumption in operation. Furthermore, the insert encompasses an additional chamber, which generates an extension force when pressurized. As such, this new actuator provides a unique bi-directional actuation capability, and, thus, has a potential to significantly simplify the design of a muscle actuator-powered robotic system. To demonstrate this new actuator concept, a prototype has been designed and fabricated, and experiments conducted on this prototype demonstrated the enhanced force capacity and the unique bi-directional actuation capability. PMID:25264492

Double-Acting Sleeve Muscle Actuator for Bio-Robotic Systems.

Science.gov (United States)

Zheng, Hao; Shen, Xiangrong

2013-11-25

This paper presents a new type of muscle-like actuator, namely double-acting (DA) sleeve muscle actuator, which is suitable for the actuation of biologically-inspired and biomedical robotic systems, especially those serving human-assistance purposes (prostheses, orthoses, etc .). Developed based on the traditional pneumatic muscle actuator, the new DA sleeve muscle incorporates a unique insert at the center. With the insert occupying the central portion of the internal volume, this new actuator enjoys multiple advantages relative to the traditional pneumatic muscle, including a consistent increase of force capacity over the entire range of motion, and a significant decrease of energy consumption in operation. Furthermore, the insert encompasses an additional chamber, which generates an extension force when pressurized. As such, this new actuator provides a unique bi-directional actuation capability, and, thus, has a potential to significantly simplify the design of a muscle actuator-powered robotic system. To demonstrate this new actuator concept, a prototype has been designed and fabricated, and experiments conducted on this prototype demonstrated the enhanced force capacity and the unique bi-directional actuation capability.

A neuro-mechanical model of a single leg joint highlighting the basic physiological role of fast and slow muscle fibres of an insect muscle system.

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Tibor Istvan Toth

Full Text Available In legged animals, the muscle system has a dual function: to produce forces and torques necessary to move the limbs in a systematic way, and to maintain the body in a static position. These two functions are performed by the contribution of specialized motor units, i.e. motoneurons driving sets of specialized muscle fibres. With reference to their overall contraction and metabolic properties they are called fast and slow muscle fibres and can be found ubiquitously in skeletal muscles. Both fibre types are active during stepping, but only the slow ones maintain the posture of the body. From these findings, the general hypothesis on a functional segregation between both fibre types and their neuronal control has arisen. Earlier muscle models did not fully take this aspect into account. They either focused on certain aspects of muscular function or were developed to describe specific behaviours only. By contrast, our neuro-mechanical model is more general as it allows functionally to differentiate between static and dynamic aspects of movement control. It does so by including both muscle fibre types and separate motoneuron drives. Our model helps to gain a deeper insight into how the nervous system might combine neuronal control of locomotion and posture. It predicts that (1 positioning the leg at a specific retraction angle in steady state is most likely due to the extent of recruitment of slow muscle fibres and not to the force developed in the individual fibres of the antagonistic muscles; (2 the fast muscle fibres of antagonistic muscles contract alternately during stepping, while co-contraction of the slow muscle fibres takes place during steady state; (3 there are several possible ways of transition between movement and steady state of the leg achieved by varying the time course of recruitment of the fibres in the participating muscles.

Overexpression of IGF-1 attenuates skeletal muscle damage and accelerates muscle regeneration and functional recovery after disuse

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Ye, Fan; Mathur, Sunita; Liu, Min; Borst, Stephen E.; Walter, Glenn A.; Sweeney, H. Lee; Vandenborne, Krista

2014-01-01

Skeletal muscle is a highly dynamic tissue that responds to endogenous and external stimuli, including alterations in mechanical loading and growth factors. In particular, the antigravity soleus muscle experiences significant muscle atrophy during disuse and extensive muscle damage upon reloading. Since insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair and modulation of muscle size, we examined the effect of viral mediated overexpression of IGF-1 on the soleus muscle following hindlimb cast immobilization and upon reloading. Recombinant IGF-1 cDNA virus was injected into one of the posterior hindlimbs of the mice, while the contralateral limb was injected with saline (control). At 20 weeks of age, both hindlimbs were immobilized for two weeks to induce muscle atrophy in the soleus and ankle plantar flexor muscle group. Subsequently, the mice were allowed to reambulate and muscle damage and recovery was monitored over a period of 2 to 21 days. The primary finding of this study was that IGF-1 overexpression attenuated reloading-induced muscle damage in the soleus muscle, and accelerated muscle regeneration and force recovery. Muscle T2 assessed by MRI, a nonspecific marker of muscle damage, was significantly lower in IGF-1 injected, compared to contralateral soleus muscles at 2 and 5 days reambulation (P<0.05). The reduced prevalence of muscle damage in IGF-1 injected soleus muscles was confirmed on histology, with a lower fraction area of abnormal muscle tissue in IGF-I injected muscles at 2 days reambulation (33.2±3.3%vs 54.1±3.6%, P<0.05). Evidence of the effect of IGF-1 on muscle regeneration included timely increases in the number of central nuclei (21% at 5 days reambulation), paired-box transcription factor 7 (36% at 5 days), embryonic myosin (37% at 10 days), and elevated MyoD mRNA (7-fold at 2 days) in IGF-1 injected limbs (P<0.05). These findings demonstrate a potential role of IGF-1 in protecting unloaded

Impaired glycogen synthase activity and mitochondrial dysfunction in skeletal muscle

DEFF Research Database (Denmark)

Højlund, Kurt; Beck-Nielsen, Henning

2006-01-01

Insulin resistance in skeletal muscle is a major hallmark of type 2 diabetes and an early detectable abnormality in the development of this disease. The cellular mechanisms of insulin resistance include impaired insulin-mediated muscle glycogen synthesis and increased intramyocellular lipid content......, whereas impaired insulin activation of muscle glycogen synthase represents a consistent, molecular defect found in both type 2 diabetic and high-risk individuals. Despite several studies of the insulin signaling pathway believed to mediate dephosphorylation and hence activation of glycogen synthase......, the molecular mechanisms responsible for this defect remain unknown. Recently, the use of phospho-specific antibodies in human diabetic muscle has revealed hyperphosphorylation of glycogen synthase at sites not regulated by the classical insulin signaling pathway. In addition, novel approaches such as gene...

The origin of activity in the biceps brachii muscle during voluntary contractions of the contralateral elbow flexor muscles

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Zijdewind, Inge; Butler, Jane E.; Gandevia, Simon C.; Taylor, Janet L.

During strong voluntary contractions, activity is not restricted to the target muscles. Other muscles, including contralateral muscles, often contract. We used transcranial magnetic stimulation (TMS) to analyse the origin of these unintended contralateral contractions (termed "associated"

Development of a Simple Structured Artificial Muscle Using SMA Wire

International Nuclear Information System (INIS)

Ibuki, Ryuta; Maruyama, Shigenao; Komiya, Atsuki

2006-01-01

Artificial heart muscle using SMA wire is developed to assist weaken heartbeat. Simple structure design was adopted for large output force, large displacement and rapid cyclic motion of the actuator. The actuator was designed and fabricated from the viewpoint of heat transfer. Moving performance of the actuator was experimentally measured under 10N of loading condition. Under the maximum efficiency condition, the actuator shows cyclic motion with 1mm of displacement and time period of about 2 seconds in one cycle

Skeletal muscle wasting: new role of nonclassical renin-angiotensin system.

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Cabello-Verrugio, Claudio; Rivera, Juan C; Garcia, Dominga

2017-05-01

Skeletal muscle can be affected by many physiological and pathological conditions that contribute to the development of muscle weakness, including skeletal muscle loss, inflammatory processes, or fibrosis. Therefore, research into therapeutic treatment alternatives or alleviation of these effects on skeletal muscle is of great importance. Recent studies have shown that angiotensin (1-7) [Ang-(1-7)] - a vasoactive peptide of the nonclassical axis in the renin-angiotensin system (RAS) - and its Mas receptor are expressed in skeletal muscle. Ang-(1-7), through its Mas receptor, prevents or diminishes deleterious effects induced by skeletal muscle disease or injury. Specifically, the Ang-(1-7)-Mas receptor axis modulates molecular mechanisms involved in muscle mass regulation, such as the ubiquitin proteasome pathway, the insulin-like growth factor type 1/Akt (protein kinase B) pathway, or myonuclear apoptosis, and also inflammation and fibrosis pathways. Although further research into this topic and the possible side effects of Ang-(1-7) is necessary, these findings are promising, and suggest that the Ang-(1-7)-Mas axis can be considered a possible therapeutic target for treating patients with muscular disorders.

Extracellular matrix organization in developing muscle: correlation with acetylcholine receptor aggregates.

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Bayne, E K; Anderson, M J; Fambrough, D M

1984-10-01

Monoclonal antibodies recognizing laminin, heparan sulfate proteoglycan, fibronectin, and two apparently novel connective tissue components have been used to examine the organization of extracellular matrix of skeletal muscle in vivo and in vitro. Four of the five monoclonal antibodies are described for the first time here. Immunocytochemical experiments with frozen-sectioned muscle demonstrated that both the heparan sulfate proteoglycan and laminin exhibited staining patterns identical to that expected for components of the basal lamina. In contrast, the remaining matrix constituents were detected in all regions of muscle connective tissue: the endomysium, perimysium, and epimysium. Embryonic muscle cells developing in culture elaborated an extracellular matrix, each antigen exhibiting a unique distribution. Of particular interest was the organization of extracellular matrix on myotubes: the build-up of matrix components was most apparent in plaques overlying clusters of an integral membrane protein, the acetylcholine receptor (AChR). The heparan sulfate proteoglycan was concentrated at virtually all AChR clusters and showed a remarkable level of congruence with receptor organization; laminin was detected at 70-95% of AChR clusters but often was not completely co-distributed with AChR within the cluster; fibronectin and the two other extracellular matrix antigens occurred at approximately 20, 8, and 2% of the AChR clusters, respectively, and showed little or no congruence with AChR. From observations on the distribution of extracellular matrix components in tissue cultured fibroblasts and myogenic cells, several ideas about the organization of extracellular matrix are suggested. (a) Congruence between AChR clusters and heparan sulfate proteoglycan suggests the existence of some linkage between the two molecules, possibly important for regulation of AChR distribution within the muscle membrane. (b) The qualitatively different patterns of extracellular matrix

Release of major ions during rigor mortis development in kid Longissimus dorsi muscle.

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Feidt, C; Brun-Bellut, J

1999-01-01

Ionic strength plays an important role in post mortem muscle changes. Its increase is due to ion release during the development of rigor mortis. Twelve alpine kids were used to study the effects of chilling and meat pH on ion release. Free ions were measured in Longissimus dorsi muscle by capillary electrophoresis after water extraction. All free ion concentrations increased after death, but there were differences between ions. Temperature was not a factor affecting ion release in contrast to ultimate pH value. Three release mechanisms are believed to coexist: a passive binding to proteins, which stops as pH decreases, an active segregation which stops as ATP disappears and the production of metabolites due to anaerobic glycolysis.

Integrated expression analysis of muscle hypertrophy identifies Asb2 as a negative regulator of muscle mass

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Davey, Jonathan R.; Watt, Kevin I.; Parker, Benjamin L.; Chaudhuri, Rima; Ryall, James G.; Cunningham, Louise; Qian, Hongwei; Sartorelli, Vittorio; Chamberlain, Jeffrey; James, David E.

2016-01-01

The transforming growth factor-β (TGF-β) signaling network is a critical regulator of skeletal muscle mass and function and, thus, is an attractive therapeutic target for combating muscle disease, but the underlying mechanisms of action remain undetermined. We report that follistatin-based interventions (which modulate TGF-β network activity) can promote muscle hypertrophy that ameliorates aging-associated muscle wasting. However, the muscles of old sarcopenic mice demonstrate reduced response to follistatin compared with healthy young-adult musculature. Quantitative proteomic and transcriptomic analyses of young-adult muscles identified a transcription/translation signature elicited by follistatin exposure, which included repression of ankyrin repeat and SOCS box protein 2 (Asb2). Increasing expression of ASB2 reduced muscle mass, thereby demonstrating that Asb2 is a TGF-β network–responsive negative regulator of muscle mass. In contrast to young-adult muscles, sarcopenic muscles do not exhibit reduced ASB2 abundance with follistatin exposure. Moreover, preventing repression of ASB2 in young-adult muscles diminished follistatin-induced muscle hypertrophy. These findings provide insight into the program of transcription and translation events governing follistatin-mediated adaptation of skeletal muscle attributes and identify Asb2 as a regulator of muscle mass implicated in the potential mechanistic dysfunction between follistatin-mediated muscle growth in young and old muscles. PMID:27182554

Development, organization, and remodeling of phoronid muscles from embryo to metamorphosis (Lophotrochozoa: Phoronida).

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Temereva, Elena N; Tsitrin, Eugeni B

2013-04-24

The phoronid larva, which is called the actinotrocha, is one of the most remarkable planktotrophic larval types among marine invertebrates. Actinotrochs live in plankton for relatively long periods and undergo catastrophic metamorphosis, in which some parts of the larval body are consumed by the juvenile. The development and organization of the muscular system has never been described in detail for actinotrochs and for other stages in the phoronid life cycle. In Phoronopsis harmeri, muscular elements of the preoral lobe and the collar originate in the mid-gastrula stage from mesodermal cells, which have immigrated from the anterior wall of the archenteron. Muscles of the trunk originate from posterior mesoderm together with the trunk coelom. The organization of the muscular system in phoronid larvae of different species is very complex and consists of 14 groups of muscles. The telotroch constrictor, which holds the telotroch in the larval body during metamorphosis, is described for the first time. This unusual muscle is formed by apical myofilaments of the epidermal cells. Most larval muscles are formed by cells with cross-striated organization of myofibrils. During metamorphosis, most elements of the larval muscular system degenerate, but some of them remain and are integrated into the juvenile musculature. Early steps of phoronid myogenesis reflect the peculiarities of the actinotroch larva: the muscle of the preoral lobe is the first muscle to appear, and it is important for food capture. The larval muscular system is organized in differently in different phoronid larvae, but always exhibits a complexity that probably results from the long pelagic life, planktotrophy, and catastrophic metamorphosis. Degeneration of the larval muscular system during phoronid metamorphosis occurs in two ways, i.e., by complete or by incomplete destruction of larval muscular elements. The organization and remodeling of the muscular system in phoronids exhibits the combination of

Fragility fracture risk and skeletal muscle function.

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Pérez-López, F R; Ara, I

2016-01-01

Low-intensity fractures are closely related with age-related musculoskeletal disorders, including osteoporosis, muscle dysfunction and sarcopenia, age-related chronic diseases, and pharmacological treatments. During the last years, a huge amount of information and recommendations has been released in relation to bone metabolism and mineral content. Muscle dysfunction and sarcopenia are highly prevalent during the second half of life, especially in older subjects. The development of sarcopenia may be slowed through healthy lifestyle changes, which include adequate dietary protein, vitamin D and mineral intakes, and regular physical activity. Prevention of falls should be integral, including correction in major involved factors in order to reduce fragility fracture, improve quality of life and appropriately focus clinical and economic resources. Therefore, to obtain better results a global approach is needed to prevent age-related fractures in frail patients that is not only centered on bone metabolism and antiresorptive drugs.

Reference values for muscle strength: a systematic review with a descriptive meta-analysis.

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Benfica, Poliana do Amaral; Aguiar, Larissa Tavares; Brito, Sherindan Ayessa Ferreira de; Bernardino, Luane Helena Nunes; Teixeira-Salmela, Luci Fuscaldi; Faria, Christina Danielli Coelho de Morais

2018-05-03

Muscle strength is an important component of health. To describe and evaluate the studies which have established the reference values for muscle strength on healthy individuals and to synthesize these values with a descriptive meta-analysis approach. A systematic review was performed in MEDLINE, LILACS, and SciELO databases. Studies that investigated the reference values for muscle strength of two or more appendicular/axial muscle groups of health individuals were included. Methodological quality, including risk of bias was assessed by the QUADAS-2. Data extracted included: country of the study, sample size, population characteristics, equipment/method used, and muscle groups evaluated. Of the 414 studies identified, 46 were included. Most of the studies had adequate methodological quality. Included studies evaluated: appendicular (80.4%) and axial (36.9%) muscles; adults (78.3%), elderly (58.7%), adolescents (43.5%), children (23.9%); isometric (91.3%) and isokinetic (17.4%) strength. Six studies (13%) with similar procedures were synthesized with meta-analysis. Generally, the coefficient of variation values that resulted from the meta-analysis ranged from 20.1% to 30% and were similar to those reported by the original studies. The meta-analysis synthesized the reference values of isometric strength of 14 muscle groups of the dominant/non-dominant sides of the upper/lower limbs of adults/elderly from developed countries, using dynamometers/myometer. Most of the included studies had adequate methodological quality. The meta-analysis provided reference values for the isometric strength of 14 appendicular muscle groups of the dominant/non-dominant sides, measured with dynamometers/myometers, of men/women, of adults/elderly. These data may be used to interpret the results of the evaluations and establish appropriate treatment goals. Copyright © 2018 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights

Hamster thecal cells express muscle characteristics

International Nuclear Information System (INIS)

Self, D.A.; Schroeder, P.C.; Gown, A.M.

1988-01-01

Contraction of the follicular wall about the time of ovulation appears to be a coordinated event; however, the cells that mediate it remain poorly studied. We examined the theca externa cells in the wall of hamster follicles for the presence of a functional actomyosin system, both in developing follicles and in culture. We used a monoclonal antibody (HHF35) that recognizes the alpha and gamma isoelectric variants of actin normally found in muscle, but not the beta variant associated with non-muscle sources, to evaluate large preovulatory follicles for actin content and composition. Antibody staining of sectioned ovaries showed intense circumferential reactivity in the outermost wall of developing follicles. Immunoblots from two-dimensional gels of theca externa lysates demonstrated the presence of the two muscle-specific isozymes of actin. Immunofluorescence of cultured follicular cells pulse-labeled with [3H] thymidine (for autoradiographic detection of DNA replication) revealed the presence, in many dividing cells, of actin filaments aligned primarily along the longitudinal axis of the cells. In cultures exposed to the calcium ionophore A23187 (10(-4) M) for varying periods (5 min to 1 h), contraction of many individual muscle-actin-positive cells was observed. Immunofluorescence of these cells, fixed immediately after ionophore-induced contraction, revealed compaction of the actin filaments. Our findings demonstrate that the cells of the theca externa contain muscle actins from an early stage and that these cells are capable of contraction even while proliferating in subconfluent cultures. They suggest that follicular growth may include a naturally occurring developmental sequence in which a contractile cell type proliferates in the differentiated state

Bone marrow mesenchymal cells improve muscle function in a skeletal muscle re-injury model.

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Bruno M Andrade

Full Text Available Skeletal muscle injury is the most common problem in orthopedic and sports medicine, and severe injury leads to fibrosis and muscle dysfunction. Conventional treatment for successive muscle injury is currently controversial, although new therapies, like cell therapy, seem to be promise. We developed a model of successive injuries in rat to evaluate the therapeutic potential of bone marrow mesenchymal cells (BMMC injected directly into the injured muscle. Functional and histological assays were performed 14 and 28 days after the injury protocol by isometric tension recording and picrosirius/Hematoxilin & Eosin staining, respectively. We also evaluated the presence and the fate of BMMC on treated muscles; and muscle fiber regeneration. BMMC treatment increased maximal skeletal muscle contraction 14 and 28 days after muscle injury compared to non-treated group (4.5 ± 1.7 vs 2.5 ± 0.98 N/cm2, p<0.05 and 8.4 ± 2.3 vs. 5.7 ± 1.3 N/cm2, p<0.05 respectively. Furthermore, BMMC treatment increased muscle fiber cross-sectional area and the presence of mature muscle fiber 28 days after muscle injury. However, there was no difference in collagen deposition between groups. Immunoassays for cytoskeleton markers of skeletal and smooth muscle cells revealed an apparent integration of the BMMC within the muscle. These data suggest that BMMC transplantation accelerates and improves muscle function recovery in our extensive muscle re-injury model.

Calcium ion in skeletal muscle: its crucial role for muscle function, plasticity, and disease

DEFF Research Database (Denmark)

Berchtold, M W; Brinkmeier, H; Müntener, M

2000-01-01

in the sarcoplasmic reticulum. In addition, a multitude of Ca(2+)-binding proteins is present in muscle tissue including parvalbumin, calmodulin, S100 proteins, annexins, sorcin, myosin light chains, beta-actinin, calcineurin, and calpain. These Ca(2+)-binding proteins may either exert an important role in Ca(2......Mammalian skeletal muscle shows an enormous variability in its functional features such as rate of force production, resistance to fatigue, and energy metabolism, with a wide spectrum from slow aerobic to fast anaerobic physiology. In addition, skeletal muscle exhibits high plasticity that is based...... on the potential of the muscle fibers to undergo changes of their cytoarchitecture and composition of specific muscle protein isoforms. Adaptive changes of the muscle fibers occur in response to a variety of stimuli such as, e.g., growth and differentition factors, hormones, nerve signals, or exercise...

Muscle torque of healthy individuals and individuals with spastic hemiparesis after passive static streching.

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Tatsukawa DE Freitas, Sérgio Takeshi; DE Carvalho Abreu, Elizângela Márcia; Dos Reis, Mariane Cecilia; DE Souza Cunha, Bruna; Souza Moreira Prianti, Tamires; Pupio Silva Lima, Fernanda; Oliveira Lima, Mário

2016-01-01

Spasticity is one of the main causes of contracture, muscle weakness and subsequent functional incapacity. The passive static stretching can be included as having the purpose of increasing musculoskeletal flexibility, however, it also can influence the muscle torque. The objective is to verify the immediate effect of passive static stretching in the muscle strength of healthy and those who present spastic hemiparesis. There were assessed 20 subjects, 10 spastic hemiparetic (EG) and 10 healthy individuals (CG), including both sexes, aged between 22 and 78 years. The torque of extensor muscles of the knee was analyzed using isokinetic dynamometer. Results have shown that EG has less muscle torque compared to CG ( p torque after stretching ( p torque of CG after performing the program that was prescribed. Immediately after the passive stretch, a significant torque decrease can be seen in hypertonic muscle; it is believed that this reduction may be associated with the physiological overlap between actin and myosin filaments and so preventing the muscle to develop a maximum contraction.

Emerging therapies for the treatment of skeletal muscle wasting in chronic obstructive pulmonary disease.

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Passey, Samantha L; Hansen, Michelle J; Bozinovski, Steven; McDonald, Christine F; Holland, Anne E; Vlahos, Ross

2016-10-01

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease that constitutes a major global health burden. A significant proportion of patients experience skeletal muscle wasting and loss of strength as a comorbidity of their COPD, a condition that severely impacts on their quality of life and survival. At present, the lung pathology is considered to be largely irreversible; however, the inherent adaptability of muscle tissue offers therapeutic opportunities to tackle muscle wasting and potentially reverse or delay the progression of this aspect of the disease, to improve patients' quality of life. Muscle wasting in COPD is complex, with contributions from a number of factors including inflammatory cytokines, oxidative stress, growth and anabolic hormones, nutritional status, and physical activity. In this review, we discuss current and emerging therapeutic approaches to treat muscle wasting in COPD, including a number of pharmacological therapies that are in development for muscle atrophy in other pathological states that could be of relevance for treating muscle wasting in COPD patients. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Three-Dimensional Human iPSC-Derived Artificial Skeletal Muscles Model Muscular Dystrophies and Enable Multilineage Tissue Engineering

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Sara Martina Maffioletti

2018-04-01

Full Text Available Summary: Generating human skeletal muscle models is instrumental for investigating muscle pathology and therapy. Here, we report the generation of three-dimensional (3D artificial skeletal muscle tissue from human pluripotent stem cells, including induced pluripotent stem cells (iPSCs from patients with Duchenne, limb-girdle, and congenital muscular dystrophies. 3D skeletal myogenic differentiation of pluripotent cells was induced within hydrogels under tension to provide myofiber alignment. Artificial muscles recapitulated characteristics of human skeletal muscle tissue and could be implanted into immunodeficient mice. Pathological cellular hallmarks of incurable forms of severe muscular dystrophy could be modeled with high fidelity using this 3D platform. Finally, we show generation of fully human iPSC-derived, complex, multilineage muscle models containing key isogenic cellular constituents of skeletal muscle, including vascular endothelial cells, pericytes, and motor neurons. These results lay the foundation for a human skeletal muscle organoid-like platform for disease modeling, regenerative medicine, and therapy development. : Maffioletti et al. generate human 3D artificial skeletal muscles from healthy donors and patient-specific pluripotent stem cells. These human artificial muscles accurately model severe genetic muscle diseases. They can be engineered to include other cell types present in skeletal muscle, such as vascular cells and motor neurons. Keywords: skeletal muscle, pluripotent stem cells, iPS cells, myogenic differentiation, tissue engineering, disease modeling, muscular dystrophy, organoids

The role of variable muscle adaptation to limb lengthening in the development of joint contractures: an experimental study in the goat.

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Makarov, Marina; Birch, John; Samchukov, Mikhail

2009-03-01

Muscle stiffness and joint contractures are currently regarded as the most common complications of limb lengthening. To better understand the mechanisms of joint contractures, architectural changes of all involved muscles were analyzed in 9 goats after 20% tibial lengthening with standard distraction protocol.All 13 muscles of the goat's tibia were found to be organized into an anterior compartment with 2 longitudinal and 4 pennate muscles and a posterior compartment with 1 longitudinal and 6 pennate muscles. Longitudinal muscles showed better compliance to distraction than pinnate muscles. Although muscle-to-bone lengthening ratio ranged widely (0-1.2), most of the muscles and especially those located in the posterior compartment showed much less lengthening than the bone. Muscular portions of the muscles lengthened more substantially (average, 17%) than their associated tendons (average, 7%). Muscle fiber length changes varied greatly between muscles (range, 0%-88%). Normalization of muscle fiber length revealed considerable elongation of anterior muscles fibers (25%) that was associated with an addition of new sarcomeres in series. Fiber length increase of all posterior muscles but one occurred by stretching of existing sarcomeres, with little addition or even dissolution of sarcomeres in series. This correlated with muscle mass changes showing significant muscle atrophy in the posterior compartment and better mass preservation in the anterior compartment.The study revealed striking difference in response to limb lengthening between individual muscles and muscles from antagonistic compartments in particular. Poor sarcomerogenesis in the posterior muscles leading to their insufficient length increase seems to play major role in the development of joint contractures.

Endurance exercise differentially stimulates heart and axial muscle development in zebrafish (Danio rerio)

NARCIS (Netherlands)

Meulen, T. van der; Schipper, H.; Boogaart, J.G. van den; Huising, M.O.; Kranenbarg, S.; Leeuwen, J.L. van

2006-01-01

Mechanical load is an important factor in the differentiation of cells and tissues. To investigate the effects of increased mechanical load on development of muscle and bone, zebrafish were subjected to endurance swim training for 6 h/day for 10 wk starting at 14 days after fertilization. During the

Muscle-tendon-related pain in 100 patients with hip dysplasia: prevalence and associations with self-reported hip disability and muscle strength

DEFF Research Database (Denmark)

Jacobsen, Julie Sandell; Hølmich, Per; Thorborg, Kristian

2018-01-01

The primary aim was to identify muscle-tendon-related pain in 100 patients with hip dysplasia. The secondary aim was to test whether muscle-tendon-related pain is associated with self-reported hip disability and muscle strength in patient with hip dysplasia. One hundred patients (17 men......-tendon-related pain and hip extension a significant inverse linear association between muscle-tendon-related pain and muscle strength was found ranging from -0.11 to - 0.12 Nm/kg in the adjusted analysis (P hip dysplasia with a high prevalence......) with a mean age of 29 years (SD 9) were included. Clinical entity approach was carried out to identify muscle-tendon-related pain. Associations between muscle-tendon-related pain and self-reported hip disability and muscle strength were tested with multiple regression analysis, including adjustments for age...

An artificial flexible robot arm based on pneumatic muscle actuators

Directory of Open Access Journals (Sweden)

Renn Jyh-Chyang

2017-01-01

Full Text Available The purpose of this paper is to develop a novel human-friendly artificial flexible robot arm using four parallel-connected pneumatic muscle actuators (PMAs. The PMA is a flexible silicone rubber actuator which has some behaviors nearest to the real biological muscle including translational and rotational motions. An inverse kinematic model for the motion control is also developed. Finally, from experiment results, it is proved that not only the axial contraction control of a single PMA but also the attitude control of the whole pneumatic flexible robot arm using PID controller are satisfactory.

Training-induced changes in muscle CSA,muscle strength, EMG and rate of force development in elderly subjects after long-term unilateral disuse

DEFF Research Database (Denmark)

Suetta, Charlotte; Aagaard, Per; Rosted, Anne

2004-01-01

, maximal isometric strength, RFD, and muscle activation in elderly men and women recovering from long-term muscle disuse and subsequent hip surgery. The improvement in both muscle mass and neural function is likely to have important functional implications for elderly individuals........ Thirty subjects completed the trial. In the strength-training group, significant increases were observed in maximal isometric muscle strength (24%, P impulse (27-32%, P

Muscle strength and power in persons with multiple sclerosis - A systematic review and meta-analysis.

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Jørgensen, Mlk; Dalgas, U; Wens, I; Hvid, L G

2017-05-15

Multiple sclerosis (MS) is a chronic disease in the central nervous system which causes a number of physical symptoms including impairments of muscle mechanical function (muscle strength, muscle power and explosive muscle strength (~rate of force development, RFD)). However, a full overview of the existing knowledge regarding muscle mechanical function in persons with MS (PwMS) is still pending. To systematically review 1) the psychometric properties of isokinetic dynamometry testing in PwMS, and 2) studies comparing muscle mechanical function in PwMS to matched healthy controls (HC). In addition, a meta-analysis will evaluate 3) the effects of progressive resistance training on muscle mechanical function in PwMS. A systematic literature search was performed in eight databases. To be included in the review, the study had to 1) enroll participants with a confirmed diagnosis of MS; 2) assess muscle mechanical function 3) had undergone peer-review. The psychometric properties of isokinetic dynamometry were reviewed with respect to validity, reliability, and responsiveness. Comparison of muscle strength between PwMS and HC was performed across contraction velocities, contraction modes and muscle groups, as were the rate of force development. The effects of progressive resistance training on muscle mechanical function were evaluated in a meta-analysis using a random effects model and standardized mean difference (SMD). A total of four, twenty-four, and ten studies were identified for aim 1, 2, and 3, respectively. High Intraclass correlations coefficients (range: 0.87-0.99) for isokinetic dynamometry was reported when assessing knee extensor and knee flexor muscle strength independent of contraction velocity. Compared to match HC, PwMS display impaired muscle strength, power and explosive muscle strength. Muscle strength impairments were most pronounced during maximal moderate to fast dynamic muscle contractions of the lower extremities. Progressive resistance training

Muscle-tendon-related pain in 100 patients with hip dysplasia: prevalence and associations with self-reported hip disability and muscle strength

DEFF Research Database (Denmark)

Jacobsen, Julie Sandell; Hölmich, Per; Thorborg, Kristian

2017-01-01

The primary aim was to identify muscle-tendon-related pain in 100 patients with hip dysplasia. The secondary aim was to test whether muscle-tendon-related pain is associated with self-reported hip disability and muscle strength in patient with hip dysplasia. One hundred patients (17 men......-tendon-related pain and hip extension a significant inverse linear association between muscletendon- related pain and muscle strength was found ranging from 0.11 to0.12 Nm/kg in the adjusted analysis (Phip dysplasia with a high prevalence......) with a mean age of 29 years (SD 9) were included. Clinical entity approach was carried out to identify muscle-tendon-related pain. Associations between muscle-tendon-related pain and self-reported hip disability and muscle strength were tested with multiple regression analysis, including adjustments for age...

Muscle dysmorphia in male weightlifters: a case-control study.

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Olivardia, R; Pope, H G; Hudson, J I

2000-08-01

Muscle dysmorphia is a form of body dysmorphic disorder in which individuals develop a pathological preoccupation with their muscularity. The authors interviewed 24 men with muscle dysmorphia and 30 normal comparison weightlifters, recruited from gymnasiums in the Boston area, using a battery of demographic, psychiatric, and physical measures. The men with muscle dysmorphia differed significantly from the normal comparison weightlifters on numerous measures, including body dissatisfaction, eating attitudes, prevalence of anabolic steroid use, and lifetime prevalence of DSM-IV mood, anxiety, and eating disorders. The men with muscle dysmorphia frequently described shame, embarrassment, and impairment of social and occupational functioning in association with their condition. By contrast, normal weightlifters displayed little pathology. Indeed, in an a posteriori analysis, the normal weightlifters proved closely comparable to a group of male college students recruited as a normal comparison group in an earlier study. Muscle dysmorphia appears to be a valid diagnostic entity, possibly related to a larger group of disorders, and is associated with striking and stereotypical features. Men with muscle dysmorphia differ sharply from normal weightlifters, most of whom display little psychopathology. Further research is necessary to characterize the nosology and potential treatment of this syndrome.

Development and testing of the circumvaginal muscles rating scale.

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Worth, A M; Dougherty, M C; McKey, P L

1986-01-01

The purpose of this research was to develop an instrument for clinical assessment of the circumvaginal muscles (CVM), to test the reliability of the instrument, and to correlate sample characteristics with this instrument. The 9-point CVM Rating Scale is based on four components: pressure, duration, muscle ribbing, and position of the examiner's finger during examination. Reliability of the CVM Rating Scale was ascertained by use of interrater and test-retest reliability. Interrater reliability was tested on two separate occasions, N = 10, rho = 0.6, p less than .04; N = 10, rho = 0.7, p less than .05. A test-retest sequence was conducted 10 days apart, N = 10, rho = 0.9, p less than .003. Results from these tests indicated that the CVM Rating Scale is a reliable instrument for assessing CVM. A convenience sample of 30 women, aged 18-37, in good general health was tested, using the CVM Rating Scale. Women with a history of pelvic floor reconstructive surgery were excluded. A significant positive correlation between self-reported orgasm and the CVM Rating Scale total scores was found, chi 2 = 7.5, p less than .02. No significant correlations were found between age, race, parity, episiotomy, or self-reported Kegel exercises and the CVM Rating Scale total scores. The scale is a cost-effective, time-efficient, systematic assessment, accessible in clinical settings.

A statistical model for predicting muscle performance

Science.gov (United States)

Byerly, Diane Leslie De Caix

The objective of these studies was to develop a capability for predicting muscle performance and fatigue to be utilized for both space- and ground-based applications. To develop this predictive model, healthy test subjects performed a defined, repetitive dynamic exercise to failure using a Lordex spinal machine. Throughout the exercise, surface electromyography (SEMG) data were collected from the erector spinae using a Mega Electronics ME3000 muscle tester and surface electrodes placed on both sides of the back muscle. These data were analyzed using a 5th order Autoregressive (AR) model and statistical regression analysis. It was determined that an AR derived parameter, the mean average magnitude of AR poles, significantly correlated with the maximum number of repetitions (designated Rmax) that a test subject was able to perform. Using the mean average magnitude of AR poles, a test subject's performance to failure could be predicted as early as the sixth repetition of the exercise. This predictive model has the potential to provide a basis for improving post-space flight recovery, monitoring muscle atrophy in astronauts and assessing the effectiveness of countermeasures, monitoring astronaut performance and fatigue during Extravehicular Activity (EVA) operations, providing pre-flight assessment of the ability of an EVA crewmember to perform a given task, improving the design of training protocols and simulations for strenuous International Space Station assembly EVA, and enabling EVA work task sequences to be planned enhancing astronaut performance and safety. Potential ground-based, medical applications of the predictive model include monitoring muscle deterioration and performance resulting from illness, establishing safety guidelines in the industry for repetitive tasks, monitoring the stages of rehabilitation for muscle-related injuries sustained in sports and accidents, and enhancing athletic performance through improved training protocols while reducing

Development of a functional food or drug against unloading-mediated muscle atrophy

Science.gov (United States)

Nikawa, Takeshi; Nakao, Reiko; Kagawa, Sachiko; Yamada, Chiharu; Abe, Manami; Tamura, Seiko; Kohno, Shohei; Sukeno, Akiko; Hirasaka, Katsuya; Okumura, Yuushi; Ishidoh, Kazumi

The ubiquitin-proteasome pathway is a primary regulator of muscle protein turnover, providing a mechanism for selective degradation of regulatory and structural proteins. This pathway is constitutively active in muscle fibers and mediates both intracellular signaling events and normal muscle protein turnover. However, conditions of decreased muscle use, so called unloading, remarkably stimulate activity of this pathway, resulting in loss of muscle protein. In fact, we previously reported that expression of several ubiquitin ligase genes, such as MuRF-1, Cbl-b, and Siah-1A, which are rate-limiting enzymes of the ubiquitin-proteasome proteolytic pathway, are significantly up-regulated in rat skeletal muscle during spaceflight. Moreover, we found that Cbl-b-mediated ubiquitination and degradation of IRS-1, an important intermediates of IGF-1 signal transduction, contributes to muscle atrophy during unloading. Therefore, we hypothesized that inhibition of Cbl-b-mediated ubiquitination and degradation of IRS-1 leads to prevention of muscle atrophy during unloading. In this study, we aimed to evaluate oligopeptide as an inhibitor against ubiquitination of IRS-1 by Cbl-b. We synthesized various oligopeptides that may competitively inhibit the binding of Cbl-b to IRS-1 on the basis of their structures and screened inhibitory effects of these synthesized oligopeptides on Cbl-b-mediated ubiquitination of IRS-1 using in vitro ubiquitination systems. We found that two synthetic oligopeptides with specific amino acid sequences effectively inhibited interaction with Cbl-b and IRS-1, resulting in decreased ubiquitination and degradation of IRS-1 (Patent pending). In contrast, we also found inhibitory activity against Cbl-b-mediated ubiquitination of IRS-1 in soy protein-derived oligopeptides, whereas their inhibitory effects were weaker than those of synthetic oligopeptides. Our results suggest that specific oligopeptides may be available as a functional food against the muscle

Muscle Synergy-Driven Robust Motion Control.

Science.gov (United States)

Min, Kyuengbo; Iwamoto, Masami; Kakei, Shinji; Kimpara, Hideyuki

2018-04-01

Humans are able to robustly maintain desired motion and posture under dynamically changing circumstances, including novel conditions. To accomplish this, the brain needs to optimize the synergistic control between muscles against external dynamic factors. However, previous related studies have usually simplified the control of multiple muscles using two opposing muscles, which are minimum actuators to simulate linear feedback control. As a result, they have been unable to analyze how muscle synergy contributes to motion control robustness in a biological system. To address this issue, we considered a new muscle synergy concept used to optimize the synergy between muscle units against external dynamic conditions, including novel conditions. We propose that two main muscle control policies synergistically control muscle units to maintain the desired motion against external dynamic conditions. Our assumption is based on biological evidence regarding the control of multiple muscles via the corticospinal tract. One of the policies is the group control policy (GCP), which is used to control muscle group units classified based on functional similarities in joint control. This policy is used to effectively resist external dynamic circumstances, such as disturbances. The individual control policy (ICP) assists the GCP in precisely controlling motion by controlling individual muscle units. To validate this hypothesis, we simulated the reinforcement of the synergistic actions of the two control policies during the reinforcement learning of feedback motion control. Using this learning paradigm, the two control policies were synergistically combined to result in robust feedback control under novel transient and sustained disturbances that did not involve learning. Further, by comparing our data to experimental data generated by human subjects under the same conditions as those of the simulation, we showed that the proposed synergy concept may be used to analyze muscle synergy

Effect of altering starting length and activation timing of muscle on fiber strain and muscle damage.

Science.gov (United States)

Butterfield, Timothy A; Herzog, Walter

2006-05-01

Muscle strain injuries are some of the most frequent injuries in sports and command a great deal of attention in an effort to understand their etiology. These injuries may be the culmination of a series of subcellular events accumulated through repetitive lengthening (eccentric) contractions during exercise, and they may be influenced by a variety of variables including fiber strain magnitude, peak joint torque, and starting muscle length. To assess the influence of these variables on muscle injury magnitude in vivo, we measured fiber dynamics and joint torque production during repeated stretch-shortening cycles in the rabbit tibialis anterior muscle, at short and long muscle lengths, while varying the timing of activation before muscle stretch. We found that a muscle subjected to repeated stretch-shortening cycles of constant muscle-tendon unit excursion exhibits significantly different joint torque and fiber strains when the timing of activation or starting muscle length is changed. In particular, measures of fiber strain and muscle injury were significantly increased by altering activation timing and increasing the starting length of the muscle. However, we observed differential effects on peak joint torque during the cyclic stretch-shortening exercise, as increasing the starting length of the muscle did not increase torque production. We conclude that altering activation timing and muscle length before stretch may influence muscle injury by significantly increasing fiber strain magnitude and that fiber dynamics is a more important variable than muscle-tendon unit dynamics and torque production in influencing the magnitude of muscle injury.

Development and Validation of the Total HUman Model for Safety (THUMS) Version 5 Containing Multiple 1D Muscles for Estimating Occupant Motions with Muscle Activation During Side Impacts.

Science.gov (United States)

Iwamoto, Masami; Nakahira, Yuko

2015-11-01

Accurate prediction of occupant head kinematics is critical for better understanding of head/face injury mechanisms in side impacts, especially far-side occupants. In light of the fact that researchers have demonstrated that muscle activations, especially in neck muscles, can affect occupant head kinematics, a human body finite element (FE) model that considers muscle activation is useful for predicting occupant head kinematics in real-world automotive accidents. In this study, we developed a human body FE model called the THUMS (Total HUman Model for Safety) Version 5 that contains 262 one-dimensional (1D) Hill-type muscle models over the entire body. The THUMS was validated against 36 series of PMHS (Post Mortem Human Surrogate) and volunteer test data in this study, and 16 series of PMHS and volunteer test data on side impacts are presented. Validation results with force-time curves were also evaluated quantitatively using the CORA (CORrelation and Analysis) method. The validation results suggest that the THUMS has good biofidelity in the responses of the regional or full body for side impacts, but relatively poor biofidelity in its local level of responses such as brain displacements. Occupant kinematics predicted by the THUMS with a muscle controller using 22 PID (Proportional-Integral- Derivative) controllers were compared with those of volunteer test data on low-speed lateral impacts. The THUMS with muscle controller reproduced the head kinematics of the volunteer data more accurately than that without muscle activation, although further studies on validation of torso kinematics are needed for more accurate predictions of occupant head kinematics.

Skeletal muscle regeneration is modulated by inflammation

Directory of Open Access Journals (Sweden)

Wenjun Yang

2018-04-01

Full Text Available Skeletal muscle regeneration is a complex process orchestrated by multiple steps. Recent findings indicate that inflammatory responses could play central roles in bridging initial muscle injury responses and timely muscle injury reparation. The various types of immune cells and cytokines have crucial roles in muscle regeneration process. In this review, we briefly summarise the functions of acute inflammation in muscle regeneration. The translational potential of this article: Immune system is closely relevant to the muscle regeneration. Understanding the mechanisms of inflammation in muscle regeneration is therefore critical for the development of effective regenerative, and therapeutic strategies in muscular disorders. This review provides information for muscle regeneration research regarding the effects of inflammation on muscle regeneration. Keywords: Chronic muscle disorders, Cytokines, Immune cells, Inflammation, Muscle regeneration, Muscle stem cells

A predictive model of muscle excitations based on muscle modularity for a large repertoire of human locomotion conditions

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Jose eGonzalez-Vargas

2015-09-01

Full Text Available Humans can efficiently walk across a large variety of terrains and locomotion conditions with little or no mental effort. It has been hypothesized that the nervous system simplifies neuromuscular control by using muscle synergies, thus organizing multi-muscle activity into a small number of coordinative co-activation modules. In the present study we investigated how muscle modularity is structured across a large repertoire of locomotion conditions including five different speeds and five different ground elevations. For this we have used the non-negative matrix factorization technique in order to explain EMG experimental data with a low-dimensional set of four motor components. In this context each motor components is composed of a non-negative factor and the associated muscle weightings. Furthermore, we have investigated if the proposed descriptive analysis of muscle modularity could be translated into a predictive model that could: 1 Estimate how motor components modulate across locomotion speeds and ground elevations. This implies not only estimating the non-negative factors temporal characteristics, but also the associated muscle weighting variations. 2 Estimate how the resulting muscle excitations modulate across novel locomotion conditions and subjects.The results showed three major distinctive features of muscle modularity: 1 the number of motor components was preserved across all locomotion conditions, 2 the non-negative factors were consistent in shape and timing across all locomotion conditions, and 3 the muscle weightings were modulated as distinctive functions of locomotion speed and ground elevation. Results also showed that the developed predictive model was able to reproduce well the muscle modularity of un-modeled data, i.e. novel subjects and conditions. Muscle weightings were reconstructed with a cross-correlation factor greater than 70% and a root mean square error less than 0.10. Furthermore, the generated muscle excitations

ATP, IMP, and glycogen in cod muscle at onset and during development of rigor mortis depend on the sampling location

DEFF Research Database (Denmark)

Cappeln, Gertrud; Jessen, Flemming

2002-01-01

Variation in glycogen, ATP, and IMP contents within individual cod muscles were studied in ice stored fish during the progress of rigor mortis. Rigor index was determined before muscle samples for chemical analyzes were taken at 16 different positions on the fish. During development of rigor......, the contents of glycogen and ATP decreased differently in relation to rigor index depending on sampling location. Although fish were considered to be in strong rigor according to the rigor index method, parts of the muscle were not in rigor as high ATP concentrations were found in dorsal and tall muscle....

Identification of telocytes in skeletal muscle interstitium: implication for muscle regeneration.

Science.gov (United States)

Popescu, L M; Manole, Emilia; Serboiu, Crenguţa S; Manole, C G; Suciu, Laura C; Gherghiceanu, Mihaela; Popescu, B O

2011-06-01

Skeletal muscle interstitium is crucial for regulation of blood flow, passage of substances from capillaries to myocytes and muscle regeneration. We show here, probably, for the first time, the presence of telocytes (TCs), a peculiar type of interstitial (stromal) cells, in rat, mouse and human skeletal muscle. TC features include (as already described in other tissues) a small cell body and very long and thin cell prolongations-telopodes (Tps) with moniliform appearance, dichotomous branching and 3D-network distribution. Transmission electron microscopy (TEM) revealed close vicinity of Tps with nerve endings, capillaries, satellite cells and myocytes, suggesting a TC role in intercellular signalling (via shed vesicles or exosomes). In situ immunolabelling showed that skeletal muscle TCs express c-kit, caveolin-1 and secrete VEGF. The same phenotypic profile was demonstrated in cell cultures. These markers and TEM data differentiate TCs from both satellite cells (e.g. TCs are Pax7 negative) and fibroblasts (which are c-kit negative). We also described non-satellite (resident) progenitor cell niche. In culture, TCs (but not satellite cells) emerge from muscle explants and form networks suggesting a key role in muscle regeneration and repair, at least after trauma. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Vitamin D and muscle trophicity.

Science.gov (United States)

Domingues-Faria, Carla; Boirie, Yves; Walrand, Stéphane

2017-05-01

We review recent findings on the involvement of vitamin D in skeletal muscle trophicity. Vitamin D deficiencies are associated with reduced muscle mass and strength, and its supplementation seems effective to improve these parameters in vitamin D-deficient study participants. Latest investigations have also evidenced that vitamin D is essential in muscle development and repair. In particular, it modulates skeletal muscle cell proliferation and differentiation. However, discrepancies still exist about an enhancement or a decrease of muscle proliferation and differentiation by the vitamin D. Recently, it has been demonstrated that vitamin D influences skeletal muscle cell metabolism as it seems to regulate protein synthesis and mitochondrial function. Finally, apart from its genomic and nongenomic effects, recent investigations have demonstrated a genetic contribution of vitamin D to muscle functioning. Recent studies support the importance of vitamin D in muscle health, and the impact of its deficiency in regard to muscle mass and function. These 'trophic' properties are of particular importance for some specific populations such as elderly persons and athletes, and in situations of loss of muscle mass or function, particularly in the context of chronic diseases.

Genome-wide identification and characterization of long non-coding RNAs in developmental skeletal muscle of fetal goat.

Science.gov (United States)

Zhan, Siyuan; Dong, Yao; Zhao, Wei; Guo, Jiazhong; Zhong, Tao; Wang, Linjie; Li, Li; Zhang, Hongping

2016-08-22

Long non-coding RNAs (lncRNAs) have been studied extensively over the past few years. Large numbers of lncRNAs have been identified in mouse, rat, and human, and some of them have been shown to play important roles in muscle development and myogenesis. However, there are few reports on the characterization of lncRNAs covering all the development stages of skeletal muscle in livestock. RNA libraries constructed from developing longissimus dorsi muscle of fetal (45, 60, and 105 days of gestation) and postnatal (3 days after birth) goat (Capra hircus) were sequenced. A total of 1,034,049,894 clean reads were generated. Among them, 3981 lncRNA transcripts corresponding to 2739 lncRNA genes were identified, including 3515 intergenic lncRNAs and 466 anti-sense lncRNAs. Notably, in pairwise comparisons between the libraries of skeletal muscle at the different development stages, a total of 577 transcripts were differentially expressed (P development-related processes, indicating they may be in cis-regulatory relationships. Additionally, Pearson's correlation coefficients of co-expression levels suggested 1737 lncRNAs and 19,422 mRNAs were possibly in trans-regulatory relationships (r > 0.95 or r development-related biological processes such as muscle system processes, regulation of cell growth, muscle cell development, regulation of transcription, and embryonic morphogenesis. This study provides a catalog of goat muscle-related lncRNAs, and will contribute to a fuller understanding of the molecular mechanism underpinning muscle development in mammals.

Development of body weight support gait training system using antagonistic bi-articular muscle model.

Science.gov (United States)

Shibata, Yoshiyuki; Imai, Shingo; Nobutomo, Tatsuya; Miyoshi, Tasuku; Yamamoto, Shin-Ichiroh

2010-01-01

The purpose of this study is to develop a body weight support gait training system for stroke and spinal cord injury. This system consists of a powered orthosis, treadmill and equipment of body weight support. Attachment of the powered orthosis is able to fit subject who has difference of body size. This powered orthosis is driven by pneumatic McKibben actuator. Actuators are arranged as pair of antagonistic bi-articular muscle model and two pairs of antagonistic mono-articular muscle model like human musculoskeletal system. Part of the equipment of body weight support suspend subject by wire harness, and body weight of subject is supported continuously by counter weight. The powered orthosis is attached equipment of body weight support by parallel linkage, and movement of the powered orthosis is limited at sagittal plane. Weight of the powered orthosis is compensated by parallel linkage with gas-spring. In this study, we developed system that has orthosis powered by pneumatic McKibben actuators and equipment of body weight support. We report detail of our developed body weight support gait training system.

A muscle model for hybrid muscle activation

Directory of Open Access Journals (Sweden)

Klauer Christian

2015-09-01

Full Text Available To develop model-based control strategies for Functional Electrical Stimulation (FES in order to support weak voluntary muscle contractions, a hybrid model for describing joint motions induced by concurrent voluntary-and FES induced muscle activation is proposed. It is based on a Hammerstein model – as commonly used in feedback controlled FES – and exemplarily applied to describe the shoulder abduction joint angle. Main component of a Hammerstein muscle model is usually a static input nonlinearity depending on the stimulation intensity. To additionally incorporate voluntary contributions, we extended the static non-linearity by a second input describing the intensity of the voluntary contribution that is estimated by electromyography (EMG measurements – even during active FES. An Artificial Neural Network (ANN is used to describe the static input non-linearity. The output of the ANN drives a second-order linear dynamical system that describes the combined muscle activation and joint angle dynamics. The tunable parameters are adapted to the individual subject by a system identification approach using previously recorded I/O-data. The model has been validated in two healthy subjects yielding RMS values for the joint angle error of 3.56° and 3.44°, respectively.

Muscles of mastication model-based MR image segmentation

Energy Technology Data Exchange (ETDEWEB)

Ng, H.P. [NUS Graduate School for Integrative Sciences and Engineering, Singapore (Singapore); Agency for Science Technology and Research, Singapore (Singapore). Biomedical Imaging Lab.; Ong, S.H. [National Univ. of Singapore (Singapore). Dept. of Electrical and Computer Engineering; National Univ. of Singapore (Singapore). Div. of Bioengineering; Hu, Q.; Nowinski, W.L. [Agency for Science Technology and Research, Singapore (Singapore). Biomedical Imaging Lab.; Foong, K.W.C. [NUS Graduate School for Integrative Sciences and Engineering, Singapore (Singapore); National Univ. of Singapore (Singapore). Dept. of Preventive Dentistry; Goh, P.S. [National Univ. of Singapore (Singapore). Dept. of Diagnostic Radiology

2006-11-15

Objective: The muscles of mastication play a major role in the orodigestive system as the principal motive force for the mandible. An algorithm for segmenting these muscles from magnetic resonance (MR) images was developed and tested. Materials and methods: Anatomical information about the muscles of mastication in MR images is used to obtain the spatial relationships relating the muscle region of interest (ROI) and head ROI. A model-based technique that involves the spatial relationships between head and muscle ROIs as well as muscle templates is developed. In the segmentation stage, the muscle ROI is derived from the model. Within the muscle ROI, anisotropic diffusion is applied to smooth the texture, followed by thresholding to exclude bone and fat. The muscle template and morphological operators are employed to obtain an initial estimate of the muscle boundary, which then serves as the input contour to the gradient vector flow snake that iterates to the final segmentation. Results: The method was applied to segmentation of the masseter, lateral pterygoid and medial pterygoid in 75 images. The overlap indices (K) achieved are 91.4, 92.1 and 91.2%, respectively. Conclusion: A model-based method for segmenting the muscles of mastication from MR images was developed and tested. The results show good agreement between manual and automatic segmentations. (orig.)

Muscles of mastication model-based MR image segmentation

International Nuclear Information System (INIS)

Ng, H.P.; Agency for Science Technology and Research, Singapore; Ong, S.H.; National Univ. of Singapore; Hu, Q.; Nowinski, W.L.; Foong, K.W.C.; National Univ. of Singapore; Goh, P.S.

2006-01-01

Objective: The muscles of mastication play a major role in the orodigestive system as the principal motive force for the mandible. An algorithm for segmenting these muscles from magnetic resonance (MR) images was developed and tested. Materials and methods: Anatomical information about the muscles of mastication in MR images is used to obtain the spatial relationships relating the muscle region of interest (ROI) and head ROI. A model-based technique that involves the spatial relationships between head and muscle ROIs as well as muscle templates is developed. In the segmentation stage, the muscle ROI is derived from the model. Within the muscle ROI, anisotropic diffusion is applied to smooth the texture, followed by thresholding to exclude bone and fat. The muscle template and morphological operators are employed to obtain an initial estimate of the muscle boundary, which then serves as the input contour to the gradient vector flow snake that iterates to the final segmentation. Results: The method was applied to segmentation of the masseter, lateral pterygoid and medial pterygoid in 75 images. The overlap indices (K) achieved are 91.4, 92.1 and 91.2%, respectively. Conclusion: A model-based method for segmenting the muscles of mastication from MR images was developed and tested. The results show good agreement between manual and automatic segmentations. (orig.)

Development, organization, and remodeling of phoronid muscles from embryo to metamorphosis (Lophotrochozoa: Phoronida)

Science.gov (United States)

2013-01-01

Background The phoronid larva, which is called the actinotrocha, is one of the most remarkable planktotrophic larval types among marine invertebrates. Actinotrochs live in plankton for relatively long periods and undergo catastrophic metamorphosis, in which some parts of the larval body are consumed by the juvenile. The development and organization of the muscular system has never been described in detail for actinotrochs and for other stages in the phoronid life cycle. Results In Phoronopsis harmeri, muscular elements of the preoral lobe and the collar originate in the mid-gastrula stage from mesodermal cells, which have immigrated from the anterior wall of the archenteron. Muscles of the trunk originate from posterior mesoderm together with the trunk coelom. The organization of the muscular system in phoronid larvae of different species is very complex and consists of 14 groups of muscles. The telotroch constrictor, which holds the telotroch in the larval body during metamorphosis, is described for the first time. This unusual muscle is formed by apical myofilaments of the epidermal cells. Most larval muscles are formed by cells with cross-striated organization of myofibrils. During metamorphosis, most elements of the larval muscular system degenerate, but some of them remain and are integrated into the juvenile musculature. Conclusion Early steps of phoronid myogenesis reflect the peculiarities of the actinotroch larva: the muscle of the preoral lobe is the first muscle to appear, and it is important for food capture. The larval muscular system is organized in differently in different phoronid larvae, but always exhibits a complexity that probably results from the long pelagic life, planktotrophy, and catastrophic metamorphosis. Degeneration of the larval muscular system during phoronid metamorphosis occurs in two ways, i.e., by complete or by incomplete destruction of larval muscular elements. The organization and remodeling of the muscular system in phoronids

Knee extensor muscle strength in middle-aged and older individuals undergoing arthroscopic partial meniscectomy

DEFF Research Database (Denmark)

Hall, Michelle; Juhl, Carsten B; Lund, Hans

2015-01-01

OBJECTIVE: People with meniscal tears are at high risk to develop or progress knee osteoarthritis. Knee extensor weakness is considered a risk factor for osteoarthritis and is often reported in these individuals. The purpose of this systematic review and meta-analysis was to investigate knee...... for a meniscal tear and used either a healthy control group or the contralateral leg to compare knee extensor muscle strength were included. Methodological quality was assessed using guidelines from the Centre for Reviews and Dissemination. RESULTS: Eleven studies, including predominately males were included (n...... and knee extensor muscle weakness are risk factors for osteoarthritis these results highlight the clinical importance of addressing muscle weakness in these individuals. This article is protected by copyright. All rights reserved....

The Association of Vitamin D Status in Lower Extremity Muscle Strains and Core Muscle Injuries at the National Football League Combine.

Science.gov (United States)

Rebolledo, Brian J; Bernard, Johnathan A; Werner, Brian C; Finlay, Andrea K; Nwachukwu, Benedict U; Dare, David M; Warren, Russell F; Rodeo, Scott A

2018-04-01

To evaluate the association between serum vitamin D level and the prevalence of lower extremity muscle strains and core muscle injuries in elite level athletes at the National Football League (NFL) combine. During the 2015 NFL combine, all athletes with available serum vitamin D levels were included for study. Baseline data were collected, including age, race, body mass index, position, injury history specific to lower extremity muscle strain or core muscle injury, and Functional Movement Screen scores. Serum 25-hydroxyvitamin D was collected and defined as normal (≥32 ng/mL), insufficient (20-31 ng/mL), and deficient (history. Subsequent multivariate regression analysis was used to examine this relation with adjustment for collected baseline data variables. The study population included 214 athletes, including 78% African American athletes and 51% skilled position players. Inadequate vitamin D was present in 59%, including 10% with deficient levels. Lower extremity muscle strain or core muscle injury was present in 50% of athletes, which was associated with lower vitamin D levels (P = .03). Athletes with a positive injury history also showed significantly lower vitamin D levels as compared with uninjured athletes (P = .03). African American/black race (P history (P history (P = .07). Inadequate vitamin D levels are a widespread finding in athletes at the NFL combine. Players with a history of lower extremity muscle strain and core muscle injury had a higher prevalence of inadequate vitamin D. Level IV, retrospective study-case series. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Development of a soft untethered robot using artificial muscle actuators

Science.gov (United States)

Cao, Jiawei; Qin, Lei; Lee, Heow Pueh; Zhu, Jian

2017-04-01

Soft robots have attracted much interest recently, due to their potential capability to work effectively in unstructured environment. Soft actuators are key components in soft robots. Dielectric elastomer actuators are one class of soft actuators, which can deform in response to voltage. Dielectric elastomer actuators exhibit interesting attributes including large voltage-induced deformation and high energy density. These attributes make dielectric elastomer actuators capable of functioning as artificial muscles for soft robots. It is significant to develop untethered robots, since connecting the cables to external power sources greatly limits the robots' functionalities, especially autonomous movements. In this paper we develop a soft untethered robot based on dielectric elastomer actuators. This robot mainly consists of a deformable robotic body and two paper-based feet. The robotic body is essentially a dielectric elastomer actuator, which can expand or shrink at voltage on or off. In addition, the two feet can achieve adhesion or detachment based on the mechanism of electroadhesion. In general, the entire robotic system can be controlled by electricity or voltage. By optimizing the mechanical design of the robot (the size and weight of electric circuits), we put all these components (such as batteries, voltage amplifiers, control circuits, etc.) onto the robotic feet, and the robot is capable of realizing autonomous movements. Experiments are conducted to study the robot's locomotion. Finite element method is employed to interpret the deformation of dielectric elastomer actuators, and the simulations are qualitatively consistent with the experimental observations.

Muscle Strength and Poststroke Hemiplegia

DEFF Research Database (Denmark)

Kristensen, Otto H; Stenager, Egon; Dalgas, Ulrik

2017-01-01

undergone peer review; and (4) were available in English or Danish. DATA EXTRACTION: The psychometric properties of isokinetic dynamometry were reviewed with respect to reliability, validity, and responsiveness. Furthermore, comparisons of strength between paretic, nonparetic, and comparable healthy muscles...... isokinetic dynamometry. DATA SOURCES: A systematic literature search of 7 databases was performed. STUDY SELECTION: Included studies (1) enrolled participants with definite poststroke hemiplegia according to defined criteria; (2) assessed muscle strength or power by criterion isokinetic dynamometry; (3) had...... were reviewed. DATA SYNTHESIS: Twenty studies covering 316 PPSH were included. High intraclass correlation coefficient (ICC) inter- and intrasession reliability was reported for isokinetic dynamometry, which was independent of the tested muscle group, contraction mode, and contraction velocity...

Dynamic cardiomyoplasty using artificial muscle.

Science.gov (United States)

Suzuki, Yasuyuki; Daitoku, Kazuyuki; Minakawa, Masahito; Fukui, Kozo; Fukuda, Ikuo

2008-01-01

Dynamic cardiomyoplasty using latissimus dorsi muscle was previously used to compensate for congestive heart failure. Now, however, this method is not acceptable because the long-term result was not as expected owing to fatigue of the skeletal muscle. BioMetal fiber developed by Toki Corporation is one of the artificial muscles activated by electric current. The behavior of this fiber is similar to that of organic muscle. We made an artificial muscle like the latissimus dorsi using BioMetal fiber and tested whether we could use this new muscle as a cardiac supporting device. Testing one Biometal fiber showed the following performance: practical use maximal generative force was 30 g, exercise variation was 50%, and the standard driving current was 220 mA. We created a 4 x 12-cm tabular artificial muscle using 8 BioMetal fibers as a cardiac support device. We also made a simulation circuit composed of a 6 x 8-cm soft bag with unidirectional valves, reservoir, and connecting tube. The simulation circuit was filled with water and the soft bag was wrapped with the artificial muscle device. After powering the device electrically at 9 V with a current of 220 mA for each fiber, we measured the inside pressure and observed the movement of the artificial device. The artificial muscle contracted in 0.5 s for peak time and squeezed the soft bag. The peak pressure inside the soft bag was measured as 10 mmHg. Although further work will be needed to enhance the speed of deformability and movement simulating contraction, we conclude that artificial muscle may be potentially useful as a cardiac assistance device that can be developed for dynamic cardiomyoplasty.

Neuropathic Pain-like Alterations in Muscle Nociceptor Function Associated with Vibration-induced Muscle Pain

OpenAIRE

Chen, Xiaojie; Green, Paul G.; Levine, Jon D.

2010-01-01

We recently developed a rodent model of the painful muscle disorders induced by occupational exposure to vibration. In the present study we used this model to evaluate the function of sensory neurons innervating the vibration-exposed gastrocnemius muscle. Activity of 74 vibration-exposed and 40 control nociceptors, with mechanical receptive fields in the gastrocnemius muscle, were recorded. In vibration-exposed rats ~15% of nociceptors demonstrated an intense and long-lasting barrage of actio...

Evaluation of methods for extraction of the volitional EMG in dynamic hybrid muscle activation

Directory of Open Access Journals (Sweden)

Mizrahi Joseph

2006-11-01

Full Text Available Abstract Background Hybrid muscle activation is a modality used for muscle force enhancement, in which muscle contraction is generated from two different excitation sources: volitional and external, by means of electrical stimulation (ES. Under hybrid activation, the overall EMG signal is the combination of the volitional and ES-induced components. In this study, we developed a computational scheme to extract the volitional EMG envelope from the overall dynamic EMG signal, to serve as an input signal for control purposes, and for evaluation of muscle forces. Methods A "synthetic" database was created from in-vivo experiments on the Tibialis Anterior of the right foot to emulate hybrid EMG signals, including the volitional and induced components. The database was used to evaluate the results obtained from six signal processing schemes, including seven different modules for filtration, rectification and ES component removal. The schemes differed from each other by their module combinations, as follows: blocking window only, comb filter only, blocking window and comb filter, blocking window and peak envelope, comb filter and peak envelope and, finally, blocking window, comb filter and peak envelope. Results and conclusion The results showed that the scheme including all the modules led to an excellent approximation of the volitional EMG envelope, as extracted from the hybrid signal, and underlined the importance of the artifact blocking window module in the process. The results of this work have direct implications on the development of hybrid muscle activation rehabilitation systems for the enhancement of weakened muscles.

Partial muscle carnitine palmitoyltransferase-A deficiency

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Ross, N.S.; Hoppel, C.L.

1987-01-02

After initiation of ibuprofen therapy, a 45-year-old woman developed muscle weakness and tenderness with rhabdomyolysis, culminating in respiratory failure. A muscle biopsy specimen showed a vacuolar myopathy, and markedly decreased muscle carnitine content and carnitine palmitoyltransferase activity. Following recovery, muscle carnitine content was normal but carnitine palmitoyltransferase activity was still abnormally low. The ratio of palmitoyl-coenzyme A plus carnitine to palmitoylcarnitine oxidation by muscle mitochondria isolated from the patient was markedly decreased. The authors conclude that transiently decreased muscle carnitine content interacted with partial deficiency of carnitine palmitoyltransferase-A to produce rhabdomyolysis and respiratory failure and that ibuprofen may have precipitated the clinical event.

Partial muscle carnitine palmitoyltransferase-A deficiency

International Nuclear Information System (INIS)

Ross, N.S.; Hoppel, C.L.

1987-01-01

After initiation of ibuprofen therapy, a 45-year-old woman developed muscle weakness and tenderness with rhabdomyolysis, culminating in respiratory failure. A muscle biopsy specimen showed a vacuolar myopathy, and markedly decreased muscle carnitine content and carnitine palmitoyltransferase activity. Following recovery, muscle carnitine content was normal but carnitine palmitoyltransferase activity was still abnormally low. The ratio of palmitoyl-coenzyme A plus carnitine to palmitoylcarnitine oxidation by muscle mitochondria isolated from the patient was markedly decreased. The authors conclude that transiently decreased muscle carnitine content interacted with partial deficiency of carnitine palmitoyltransferase-A to produce rhabdomyolysis and respiratory failure and that ibuprofen may have precipitated the clinical event

The morphological development of the locomotor and cardiac muscles of the migratory barnacle goose (Branta leucopsis)

NARCIS (Netherlands)

Bishop, CM; Butler, PJ; ElHaj, AJ; Egginton, S; Loonen, MJJE

The masses of the locomotor and cardiac muscles of wild barnacle goose goslings, from a migratory population, were examined systematically during development and their values compared to those of pre-migratory geese. Pre-flight development was typified by approximately linear increases of body, leg,

The use of near-infrared spectroscopy in understanding skeletal muscle physiology: recent developments.

Science.gov (United States)

Ferrari, Marco; Muthalib, Makii; Quaresima, Valentina

2011-11-28

This article provides a snapshot of muscle near-infrared spectroscopy (NIRS) at the end of 2010 summarizing the recent literature, offering the present status and perspectives of the NIRS instrumentation and methods, describing the main NIRS studies on skeletal muscle physiology, posing open questions and outlining future directions. So far, different NIRS techniques (e.g. continuous-wave (CW) and spatially, time- and frequency-resolved spectroscopy) have been used for measuring muscle oxygenation during exercise. In the last four years, approximately 160 muscle NIRS articles have been published on different physiological aspects (primarily muscle oxygenation and haemodynamics) of several upper- and lower-limb muscle groups investigated by using mainly two-channel CW and spatially resolved spectroscopy commercial instruments. Unfortunately, in only 15 of these studies were the advantages of using multi-channel instruments exploited. There are still several open questions in the application of NIRS in muscle studies: (i) whether NIRS can be used in subjects with a large fat layer; (ii) the contribution of myoglobin desaturation to the NIRS signal during exercise; (iii) the effect of scattering changes during exercise; and (iv) the effect of changes in skin perfusion, particularly during prolonged exercise. Recommendations for instrumentation advancements and future muscle NIRS studies are provided.

Ageing in relation to skeletal muscle dysfunction: redox homoeostasis to regulation of gene expression.

Science.gov (United States)

Goljanek-Whysall, Katarzyna; Iwanejko, Lesley A; Vasilaki, Aphrodite; Pekovic-Vaughan, Vanja; McDonagh, Brian

2016-08-01

Ageing is associated with a progressive loss of skeletal muscle mass, quality and function-sarcopenia, associated with reduced independence and quality of life in older generations. A better understanding of the mechanisms, both genetic and epigenetic, underlying this process would help develop therapeutic interventions to prevent, slow down or reverse muscle wasting associated with ageing. Currently, exercise is the only known effective intervention to delay the progression of sarcopenia. The cellular responses that occur in muscle fibres following exercise provide valuable clues to the molecular mechanisms regulating muscle homoeostasis and potentially the progression of sarcopenia. Redox signalling, as a result of endogenous generation of ROS/RNS in response to muscle contractions, has been identified as a crucial regulator for the adaptive responses to exercise, highlighting the redox environment as a potentially core therapeutic approach to maintain muscle homoeostasis during ageing. Further novel and attractive candidates include the manipulation of microRNA expression. MicroRNAs are potent gene regulators involved in the control of healthy and disease-associated biological processes and their therapeutic potential has been researched in the context of various disorders, including ageing-associated muscle wasting. Finally, we discuss the impact of the circadian clock on the regulation of gene expression in skeletal muscle and whether disruption of the peripheral muscle clock affects sarcopenia and altered responses to exercise. Interventions that include modifying altered redox signalling with age and incorporating genetic mechanisms such as circadian- and microRNA-based gene regulation, may offer potential effective treatments against age-associated sarcopenia.

Comparison of isokinetic muscle strength and muscle power by types of warm-up.

Science.gov (United States)

Sim, Young-Je; Byun, Yong-Hyun; Yoo, Jaehyun

2015-05-01

[Purpose] The purpose of this study was to clarify the influence of static stretching at warm-up on the isokinetic muscle torque (at 60°/sec) and muscle power (at 180°/sec) of the flexor muscle and extensor muscle of the knee joint. [Subjects and Methods] The subjects of this study were 10 healthy students with no medically specific findings. The warm-up group and warm-up with stretching group performed their respective warm-up prior to the isokinetic muscle torque evaluation of the knee joint. One-way ANOVA was performed by randomized block design for each variable. [Results] The results were as follows: First, the flexor peak torque and extensor peak torque of the knee joint tended to decrease at 60°/sec in the warm-up with stretching group compared with the control group and warm-up group, but without statistical significance. Second, extensor power at 180°/sec was also not statistically significant. However, it was found that flexor power increased significantly in the warm-up with stretching group at 180°/sec compared with the control group and warm-up group in which stretching was not performed. [Conclusion] Therefore, it is considered that in healthy adults, warm-up including two sets of stretching for 20 seconds per muscle group does not decrease muscle strength and muscle power.

Development of fatigue and discomfort in the upper trapezius muscle during light manual work

NARCIS (Netherlands)

Bosch, T.; Looze, M.P. de; Dieën, J.H. van

2007-01-01

Optimization of the temporal aspects of task design requires a better understanding of the development of muscle fatigue in the neck and shoulder region over time. The objective of the study was to investigate this in two production companies and to determine the relationship between objective and

BACK MUSCLES STRENGTH DEVELOPMENT BY MEANS OF INCREASE AND DECREASE OF EFFORT LOAD DURING GIANT SETS IN BODYBUILDING FOR MASSES

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TIMNEA OLIVIA

2013-01-01

Full Text Available Abstract The aim of the study is to highlight methodological issues on the back muscle strength development by combining methodological procedures in masses bodybuilding.Methods. The study was conducted in three stages over a period of two months (March-April 2011, performing three workouts per week, monitoring the effective use of strength exercises to develop back muscles in the same muscle area by means of giant sets during workouts. In this context, we conducted a case study in "Tonik Fitness Club" in Bucharest, applied to two athletes of 28 and 34 years old. We recorded subjects’ evolutions during the training session, using statistical and mathematical method and graphical representation method.Results. The study content highlights the training programs depending on muscle zone and the specific methodological aspects, the weekly training program per muscle groups, the stages of study carrying out, the test and control trials applied in terms of anthropometric measurements and of back muscle strength development, and the application of the methodical procedure of effort load increase and decrease within the giant sets in a training micro-cycle.Discussion. The study focused on the training programs over two months, monitoring statistically the development of back muscle strength through the application of the procedure of effort load increase and decrease during giant sets in bodybuilding for masses. From the analysis of training programs content we noticed that three giant sets of exercises were used, performed in four series; each exercise within the giant sets was applied by means of the procedure of increasing and decreasing effort load. Study results emphasize the anthropometric measurement results: the study subjects have the age mean of 24.75, with a size of 175.2 cm and a weight of 83.75 kg at initial testing and a decrease by 2.12 kg in final testing. Regarding the chest perimeter, the inspiration is averaging 89.5 in initial

Pneumatic Muscles Actuated Lower-Limb Orthosis Model Verification with Actual Human Muscle Activation Patterns

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Dzahir M.A.M

2017-01-01

Full Text Available A review study was conducted on existing lower-limb orthosis systems for rehabilitation which implemented pneumatic muscle type of actuators with the aim to clarify the current and on-going research in this field. The implementation of pneumatic artificial muscle will play an important role for the development of the advanced robotic system. In this research a derivation model for the antagonistic mono- and bi-articular muscles using pneumatic artificial muscles of a lower limb orthosis will be verified with actual human’s muscle activities models. A healthy and young male 29 years old subject with height 174cm and weight 68kg was used as a test subject. Two mono-articular muscles Vastus Medialis (VM and Vastus Lateralis (VL were selected to verify the mono-articular muscle models and muscle synergy between anterior muscles. Two biarticular muscles Rectus Femoris (RF and Bicep Femoris (BF were selected to verify the bi-articular muscle models and muscle co-contraction between anterior-posterior muscles. The test was carried out on a treadmill with a speed of 4.0 km/h, which approximately around 1.25 m/s for completing one cycle of walking motion. The data was collected for about one minute on a treadmill and 20 complete cycles of walking motion were successfully recorded. For the evaluations, the mathematical model obtained from the derivation and the actual human muscle activation patterns obtained using the surface electromyography (sEMG system were compared and analysed. The results shown that, high correlation values ranging from 0.83 up to 0.93 were obtained in between the derivation model and the actual human muscle’s model for both mono- and biarticular muscles. As a conclusion, based on the verification with the sEMG muscle activities data and its correlation values, the proposed derivation models of the antagonistic mono- and bi-articular muscles were suitable to simulate and controls the pneumatic muscles actuated lower limb

Magnetic resonance imaging of facial muscles

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Farrugia, M.E. [Department of Clinical Neurology, University of Oxford, Radcliffe Infirmary, Oxford (United Kingdom)], E-mail: m.e.farrugia@doctors.org.uk; Bydder, G.M. [Department of Radiology, University of California, San Diego, CA 92103-8226 (United States); Francis, J.M.; Robson, M.D. [OCMR, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford (United Kingdom)

2007-11-15

Facial and tongue muscles are commonly involved in patients with neuromuscular disorders. However, these muscles are not as easily accessible for biopsy and pathological examination as limb muscles. We have previously investigated myasthenia gravis patients with MuSK antibodies for facial and tongue muscle atrophy using different magnetic resonance imaging sequences, including ultrashort echo time techniques and image analysis tools that allowed us to obtain quantitative assessments of facial muscles. This imaging study had shown that facial muscle measurement is possible and that useful information can be obtained using a quantitative approach. In this paper we aim to review in detail the methods that we applied to our study, to enable clinicians to study these muscles within the domain of neuromuscular disease, oncological or head and neck specialties. Quantitative assessment of the facial musculature may be of value in improving the understanding of pathological processes occurring within facial muscles in certain neuromuscular disorders.

Magnetic resonance imaging of facial muscles

International Nuclear Information System (INIS)

Farrugia, M.E.; Bydder, G.M.; Francis, J.M.; Robson, M.D.

2007-01-01

Facial and tongue muscles are commonly involved in patients with neuromuscular disorders. However, these muscles are not as easily accessible for biopsy and pathological examination as limb muscles. We have previously investigated myasthenia gravis patients with MuSK antibodies for facial and tongue muscle atrophy using different magnetic resonance imaging sequences, including ultrashort echo time techniques and image analysis tools that allowed us to obtain quantitative assessments of facial muscles. This imaging study had shown that facial muscle measurement is possible and that useful information can be obtained using a quantitative approach. In this paper we aim to review in detail the methods that we applied to our study, to enable clinicians to study these muscles within the domain of neuromuscular disease, oncological or head and neck specialties. Quantitative assessment of the facial musculature may be of value in improving the understanding of pathological processes occurring within facial muscles in certain neuromuscular disorders

Novel, high incidence exercise-induced muscle bleeding model in hemophilia B mice

DEFF Research Database (Denmark)

Tranholm, M.; Kristensen, Annemarie Thuri; Broberg, M. L.

2015-01-01

INTRODUCTION: Muscle hematomas are the second most common complication of hemophilia and insufficient treatment may result in serious and even life-threatening complications. Hemophilic dogs and rats do experience spontaneous muscle bleeding, but currently, no experimental animal model is available...... specifically investigating spontaneous muscle bleeds in a hemophilic setting. AIM: The objective of this study was to develop a model of spontaneous muscle bleeds in hemophilia B mice. We hypothesized that treadmill exercise would induce muscle bleeds in hemophilia B mice but not in normal non-hemophilic mice...... and that treatment with recombinant factor IX (rFIX) before treadmill exercise could prevent the occurrence of pathology. METHODS: A total of 203 mice (123 F9-KO and 80 C57BL/6NTac) were included in three separate studies: (i) the model implementation study investigating the bleeding pattern in hemophilia B mice...

Inhibition of platelet-derived growth factor signaling prevents muscle fiber growth during skeletal muscle hypertrophy.

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Sugg, Kristoffer B; Korn, Michael A; Sarver, Dylan C; Markworth, James F; Mendias, Christopher L

2017-03-01

The platelet-derived growth factor receptors alpha and beta (PDGFRα and PDGFRβ) mark fibroadipogenic progenitor cells/fibroblasts and pericytes in skeletal muscle, respectively. While the role that these cells play in muscle growth and development has been evaluated, it was not known whether the PDGF receptors activate signaling pathways that control transcriptional and functional changes during skeletal muscle hypertrophy. To evaluate this, we inhibited PDGFR signaling in mice subjected to a synergist ablation muscle growth procedure, and performed analyses 3 and 10 days after induction of hypertrophy. The results from this study indicate that PDGF signaling is required for fiber hypertrophy, extracellular matrix production, and angiogenesis that occur during muscle growth. © 2017 Federation of European Biochemical Societies.

Assessment of muscle fatigue using electromygraphm sensing

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Helmi, Muhammad Hazimin Bin; Ping, Chew Sue; Ishak, Nur Elliza Binti; Saad, Mohd Alimi Bin Mohd; Mokhtar, Anis Shahida Niza Binti

2017-08-01

Muscle fatigue is condition of muscle decline in ability after undergoing any physical activity. Observation of the muscle condition of an athlete during training is crucial to prevent or minimize injury and able to achieve optimum performance in actual competition. The aim of this project is to develop a muscle monitoring system to detect muscle fatigue in swimming athlete. This device is capable to measure muscle stress level of the swimmer and at the same time provide indication of muscle fatigue level to trainer. Electromyography signal was recorded from the muscle movement while practicing the front crawl stroke repetitively. The time domain data was processed to frequency spectra in order to study the effect of muscle fatigue. The results show that the recorded EMG signal is able to sense muscle fatigue.

Glucose transporter expression in human skeletal muscle fibers

DEFF Research Database (Denmark)

Gaster, M; Handberg, A; Beck-Nielsen, H

2000-01-01

, but its expression is markedly reduced around birth and is further reduced to undetectable levels within the first year of life; 2) GLUT-3 protein expression appears at 18 wk of gestation and disappears after birth; and 3) GLUT-4 protein is diffusely expressed in muscle cells throughout gestation, whereas...... after birth, the characteristic subcellular localization is as seen in adult muscle fibers. Our results show that GLUT-1, GLUT-3, and GLUT-4 seem to be of importance during muscle fiber growth and development. GLUT-5 protein was undetectable in fetal and adult skeletal muscle fibers. In adult muscle...... amplification (TSA) technique to detect the localization of glucose transporter expression in human skeletal muscle. We found expression of GLUT-1, GLUT-3, and GLUT-4 in developing human muscle fibers showing a distinct expression pattern. 1) GLUT-1 is expressed in human skeletal muscle cells during gestation...

Botulinum toxin injection causes hyper-reflexia and increased muscle stiffness of the triceps surae muscle in the rat.

Science.gov (United States)

Pingel, Jessica; Wienecke, Jacob; Lorentzen, Jakob; Nielsen, Jens Bo

2016-12-01

Botulinum toxin is used with the intention of diminishing spasticity and reducing the risk of development of contractures. Here, we investigated changes in muscle stiffness caused by reflex activity or elastic muscle properties following botulinum toxin injection in the triceps surae muscle in rats. Forty-four rats received injection of botulinum toxin in the left triceps surae muscle. Control measurements were performed on the noninjected contralateral side in all rats. Acute experiments were performed, 1, 2, 4, and 8 wk following injection. The triceps surae muscle was dissected free, and the Achilles tendon was cut and attached to a muscle puller. The resistance of the muscle to stretches of different amplitudes and velocities was systematically investigated. Reflex-mediated torque was normalized to the maximal muscle force evoked by supramaximal stimulation of the tibial nerve. Botulinum toxin injection caused severe atrophy of the triceps surae muscle at all time points. The force generated by stretch reflex activity was also strongly diminished but not to the same extent as the maximal muscle force at 2 and 4 wk, signifying a relative reflex hyperexcitability. Passive muscle stiffness was unaltered at 1 wk but increased at 2, 4, and 8 wk (P botulinum toxin causes a relative increase in reflex stiffness, which is likely caused by compensatory neuroplastic changes. The stiffness of elastic elements in the muscles also increased. The data are not consistent with the ideas that botulinum toxin is an efficient antispastic medication or that it may prevent development of contractures. Copyright © 2016 the American Physiological Society.

PNW cetacean muscle biochemistry - Muscle Myoglobin Content and Acid Buffering Capacity of Cetaceans from the Pacific Northwest to Assess Dive Capacity and the Development of Diving Capabilities

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project assesses the development of two important skeletal muscle adaptations for diving (enhanced myoglobin content and acid buffering capacities) in a range...

Adipose, bone and muscle tissues as new endocrine organs: role of reciprocal regulation for osteoporosis and obesity development.

Science.gov (United States)

Migliaccio, Silvia; Greco, Emanuela A; Wannenes, Francesca; Donini, Lorenzo M; Lenzi, Andrea

2014-01-01

The belief that obesity is protective against osteoporosis has recently been revised. In fact, the latest epidemiologic and clinical studies show that a high level of fat mass, but also reduced muscle mass, might be a risk factor for osteoporosis and fragility fractures. Furthermore, increasing evidence seems to indicate that different components such as myokines, adipokines and growth factors, released by both fat and muscle tissues, could play a key role in the regulation of skeletal health and in low bone mineral density and, thus, in osteoporosis development. This review considers old and recent data in the literature to further evaluate the relationship between fat, bone and muscle tissue.

Tetranectin is a novel marker for myogenesis during embryonic development, muscle regeneration, and muscle cell differentiation in vitro

DEFF Research Database (Denmark)

Wewer, U M; Iba, K; Durkin, M E

1998-01-01

differentiation in vitro. We find that tetranectin expression coincides with muscle differentiation and maturation in the second half of gestation and further that tetranectin is enriched at the myotendinous and myofascial junctions. The tetranectin immunostaining declines after birth and no immunostaining...... cells in dystrophic mdx mice. Murine C2C12 myogenic cells and pluripotent embryonic stem cells can undergo muscle cell differentiation in vitro. Tetranectin is not expressed in the undifferentiated myogenic cells, but during the progression of muscle differentiation, tetranectin mRNA is induced...... that in some tissues, such as the limbs, tetranectin may function locally, whereas in other tissues, such as the lung, tetranectin production may be destined for body fluids. In summary, these results suggest that tetranectin is a matricellular protein and plays a role in myogenesis....

A muscle stem cell for every muscle: variability of satellite cell biology among different muscle groups

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Randolph, Matthew E.; Pavlath, Grace K.

2015-01-01

The human body contains approximately 640 individual skeletal muscles. Despite the fact that all of these muscles are composed of striated muscle tissue, the biology of these muscles and their associated muscle stem cell populations are quite diverse. Skeletal muscles are affected differentially by various muscular dystrophies (MDs), such that certain genetic mutations specifically alter muscle function in only a subset of muscles. Additionally, defective muscle stem cells have been implicated in the pathology of some MDs. The biology of muscle stem cells varies depending on the muscles with which they are associated. Here we review the biology of skeletal muscle stem cell populations of eight different muscle groups. Understanding the biological variation of skeletal muscles and their resident stem cells could provide valuable insight into mechanisms underlying the susceptibility of certain muscles to myopathic disease. PMID:26500547

Role of Smooth Muscle in Intestinal Inflammation

Directory of Open Access Journals (Sweden)

Stephen M Collins

1996-01-01

Full Text Available The notion that smooth muscle function is altered in inflammation is prompted by clinical observations of altered motility in patients with inflammatory bowel disease (IBD. While altered motility may reflect inflammation-induced changes in intrinsic or extrinsic nerves to the gut, changes in gut hormone release and changes in muscle function, recent studies have provided in vitro evidence of altered muscle contractility in muscle resected from patients with ulcerative colitis or Crohn’s disease. In addition, the observation that smooth muscle cells are more numerous and prominent in the strictured bowel of IBD patients compared with controls suggests that inflammation may alter the growth of intestinal smooth muscle. Thus, inflammation is associated with changes in smooth muscle growth and contractility that, in turn, contribute to important symptoms of IBD including diarrhea (from altered motility and pain (via either altered motility or stricture formation. The involvement of smooth muscle in this context may be as an innocent bystander, where cells and products of the inflammatory process induce alterations in muscle contractility and growth. However, it is likely that intestinal muscle cells play a more active role in the inflammatory process via the elaboration of mediators and trophic factors, including cytokines, and via the production of collagen. The concept of muscle cells as active participants in the intestinal inflammatory process is a new concept that is under intense study. This report summarizes current knowledge as it relates to these two aspects of altered muscle function (growth and contractility in the inflamed intestine, and will focus on mechanisms underlying these changes, based on data obtained from animal models of intestinal inflammation.

Effect of tibial bone resection on the development of fast- and slow-twitch skeletal muscles in foetal sheep.

Science.gov (United States)

West, J M; Williams, N A; Luff, A R; Walker, D W

2000-04-01

To determine if longitudinal bone growth affects the differentiation of fast- and slow-twitch muscles, the tibial bone was sectioned at 90 days gestation in foetal sheep so that the lower leg was permanently without structural support. At 140 days (term is approximately 147 days) the contractile properties of whole muscles, activation profiles of single fibres and ultrastructure of fast- and slow-twitch muscles from the hindlimbs were studied. The contractile and activation profiles of the slow-twitch soleus muscles were significantly affected by tibial bone resection (TIBX). The soleus muscles from the TIBX hindlimbs showed: (1) a decrease in the time to peak of the twitch responses from 106.2 +/- 10.7 ms (control, n = 4) to 65.1 +/- 2.48 ms (TIBX, n = 5); (2) fatigue profiles more characteristic of those observed in the fast-twitch muscles: and (3) Ca2+ - and Sr2+ -activation profiles of skinned fibres similar to those from intact hindlimbs at earlier stages of gestation. In the FDL, TIBX did not significantly change whole muscle twitch contraction time, the fatigue profile or the Ca2+ - and Sr2+ -activation profiles of skinned fibres. Electron microscopy showed an increased deposition of glycogen in both soleus and FDL muscles. This study shows that the development of the slow-twitch phenotype is impeded in the absence of the physical support normally provided by the tibial bone. We suggest that longitudinal stretch is an important factor in allowing full expression of the slow-twitch phenotype.

Is back pain during childhood or adolescence associated with muscle strength, muscle endurance or aerobic capacity

DEFF Research Database (Denmark)

Lardon, Arnaud; Leboeuf-Yde, Charlotte; Le Scanff, Christine

2015-01-01

BACKGROUND: Back pain is a common condition during childhood and adolescence. The causes of back pain are largely unknown but it seems plausible that some physical factors such as back muscle strength, back muscle endurance and aerobic capacity may play a role in its development, in particular...... aerobic capacity and back pain is not clear. CONCLUSIONS: High back muscle endurance in extension appears protective of back pain in youngsters, but the roles of high back muscle strength in extension and aerobic capacity are less clear....

Development of an orthosis for walking assistance using pneumatic artificial muscle: a quantitative assessment of the effect of assistance.

Science.gov (United States)

Kawamura, T; Takanaka, K; Nakamura, T; Osumi, H

2013-06-01

In recent years, there is an increase in the number of people that require support during walking as a result of a decrease in the leg muscle strength accompanying aging. An important index for evaluating walking ability is step length. A key cause for a decrease in step length is the loss of muscle strength in the legs. Many researchers have designed and developed orthoses for walking assistance. In this study, we advanced the design of an orthosis for walking assistance that assists the forward swing of the leg to increase step length. We employed a pneumatic artificial muscle as the actuator so that flexible assistance with low rigidity can be achieved. To evaluate the performance of the system, we measured the effect of assistance quantitatively. In this study, we constructed a prototype of the orthosis and measure EMG and step length on fitting it to a healthy subject so as to determine the effect of assistance, noting the increase in the obtained step length. Although there was an increase in EMG stemming from the need to maintain body balance during the stance phase, we observed that the EMG of the sartorius muscle, which helps swing the leg forward, decreased, and the strength of the semitendinosus muscle, which restrains the leg against over-assistance, did not increase but decreased. Our experiments showed that the assistance force provided by the developed orthosis is not adequate for the intended task, and the development of a mechanism that provides appropriate assistance is required in the future.

Three-Dimensional Human iPSC-Derived Artificial Skeletal Muscles Model Muscular Dystrophies and Enable Multilineage Tissue Engineering.

Science.gov (United States)

Maffioletti, Sara Martina; Sarcar, Shilpita; Henderson, Alexander B H; Mannhardt, Ingra; Pinton, Luca; Moyle, Louise Anne; Steele-Stallard, Heather; Cappellari, Ornella; Wells, Kim E; Ferrari, Giulia; Mitchell, Jamie S; Tyzack, Giulia E; Kotiadis, Vassilios N; Khedr, Moustafa; Ragazzi, Martina; Wang, Weixin; Duchen, Michael R; Patani, Rickie; Zammit, Peter S; Wells, Dominic J; Eschenhagen, Thomas; Tedesco, Francesco Saverio

2018-04-17

Generating human skeletal muscle models is instrumental for investigating muscle pathology and therapy. Here, we report the generation of three-dimensional (3D) artificial skeletal muscle tissue from human pluripotent stem cells, including induced pluripotent stem cells (iPSCs) from patients with Duchenne, limb-girdle, and congenital muscular dystrophies. 3D skeletal myogenic differentiation of pluripotent cells was induced within hydrogels under tension to provide myofiber alignment. Artificial muscles recapitulated characteristics of human skeletal muscle tissue and could be implanted into immunodeficient mice. Pathological cellular hallmarks of incurable forms of severe muscular dystrophy could be modeled with high fidelity using this 3D platform. Finally, we show generation of fully human iPSC-derived, complex, multilineage muscle models containing key isogenic cellular constituents of skeletal muscle, including vascular endothelial cells, pericytes, and motor neurons. These results lay the foundation for a human skeletal muscle organoid-like platform for disease modeling, regenerative medicine, and therapy development. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Action of Obestatin in Skeletal Muscle Repair: Stem Cell Expansion, Muscle Growth, and Microenvironment Remodeling

Science.gov (United States)

Gurriarán-Rodríguez, Uxía; Santos-Zas, Icía; González-Sánchez, Jessica; Beiroa, Daniel; Moresi, Viviana; Mosteiro, Carlos S; Lin, Wei; Viñuela, Juan E; Señarís, José; García-Caballero, Tomás; Casanueva, Felipe F; Nogueiras, Rubén; Gallego, Rosalía; Renaud, Jean-Marc; Adamo, Sergio; Pazos, Yolanda; Camiña, Jesús P

2015-01-01

The development of therapeutic strategies for skeletal muscle diseases, such as physical injuries and myopathies, depends on the knowledge of regulatory signals that control the myogenic process. The obestatin/GPR39 system operates as an autocrine signal in the regulation of skeletal myogenesis. Using a mouse model of skeletal muscle regeneration after injury and several cellular strategies, we explored the potential use of obestatin as a therapeutic agent for the treatment of trauma-induced muscle injuries. Our results evidenced that the overexpression of the preproghrelin, and thus obestatin, and GPR39 in skeletal muscle increased regeneration after muscle injury. More importantly, the intramuscular injection of obestatin significantly enhanced muscle regeneration by simulating satellite stem cell expansion as well as myofiber hypertrophy through a kinase hierarchy. Added to the myogenic action, the obestatin administration resulted in an increased expression of vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor 2 (VEGFR2) and the consequent microvascularization, with no effect on collagen deposition in skeletal muscle. Furthermore, the potential inhibition of myostatin during obestatin treatment might contribute to its myogenic action improving muscle growth and regeneration. Overall, our data demonstrate successful improvement of muscle regeneration, indicating obestatin is a potential therapeutic agent for skeletal muscle injury and would benefit other myopathies related to muscle regeneration. PMID:25762009

Imaging of respiratory muscles in neuromuscular disease: A review.

Science.gov (United States)

Harlaar, L; Ciet, P; van der Ploeg, A T; Brusse, E; van der Beek, N A M E; Wielopolski, P A; de Bruijne, M; Tiddens, H A W M; van Doorn, P A

2018-03-01

Respiratory muscle weakness frequently occurs in patients with neuromuscular disease. Measuring respiratory function with standard pulmonary function tests provides information about the contribution of all respiratory muscles, the lungs and airways. Imaging potentially enables the study of different respiratory muscles, including the diaphragm, separately. In this review, we provide an overview of imaging techniques used to study respiratory muscles in neuromuscular disease. We identified 26 studies which included a total of 573 patients with neuromuscular disease. Imaging of respiratory muscles was divided into static and dynamic techniques. Static techniques comprise chest radiography, B-mode (brightness mode) ultrasound, CT and MRI, and are used to assess the position and thickness of the diaphragm and the other respiratory muscles. Dynamic techniques include fluoroscopy, M-mode (motion mode) ultrasound and MRI, used to assess diaphragm motion in one or more directions. We discuss how these imaging techniques relate with spirometric values and whether these can be used to study the contribution of the different respiratory muscles in patients with neuromuscular disease. Copyright © 2017. Published by Elsevier B.V.

Skeletal muscle performance and ageing.

Science.gov (United States)

Tieland, Michael; Trouwborst, Inez; Clark, Brian C

2018-02-01

The world population is ageing rapidly. As society ages, the incidence of physical limitations is dramatically increasing, which reduces the quality of life and increases healthcare expenditures. In western society, ~30% of the population over 55 years is confronted with moderate or severe physical limitations. These physical limitations increase the risk of falls, institutionalization, co-morbidity, and premature death. An important cause of physical limitations is the age-related loss of skeletal muscle mass, also referred to as sarcopenia. Emerging evidence, however, clearly shows that the decline in skeletal muscle mass is not the sole contributor to the decline in physical performance. For instance, the loss of muscle strength is also a strong contributor to reduced physical performance in the elderly. In addition, there is ample data to suggest that motor coordination, excitation-contraction coupling, skeletal integrity, and other factors related to the nervous, muscular, and skeletal systems are critically important for physical performance in the elderly. To better understand the loss of skeletal muscle performance with ageing, we aim to provide a broad overview on the underlying mechanisms associated with elderly skeletal muscle performance. We start with a system level discussion and continue with a discussion on the influence of lifestyle, biological, and psychosocial factors on elderly skeletal muscle performance. Developing a broad understanding of the many factors affecting elderly skeletal muscle performance has major implications for scientists, clinicians, and health professionals who are developing therapeutic interventions aiming to enhance muscle function and/or prevent mobility and physical limitations and, as such, support healthy ageing. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

The Relationship between Walk Distance and Muscle Strength, Muscle Pain in Visually Disabled People

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Akyol, Betül

2018-01-01

The purpose of this study is to examine the relationship between six-minute walk test and muscle pain, muscle strength in visually disabled people. The study includes 50 visually disabled people, aged between 17, 21 ± 5,3. Participants were classified into three categories according to their degree of vision (B1, B2, B3). All participants were…

The spectrum of muscle histopathologic findings in 42 weak scleroderma patients

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Paik, Julie J.; Wigley, Fredrick M.; Lloyd, Thomas E.; Corse, Andrea M.; Casciola-Rosen, Livia; Shah, Ami A.; Boin, Francesco; Hummers, Laura K.; Mammen, Andrew L.

2015-01-01

Objective To determine if distinct muscle pathological features exist in scleroderma subjects with weakness. Methods This retrospective study included weak scleroderma subjects with muscle biopsies available for review. Biopsies were systematically assessed for individual pathologic features including inflammation, necrosis, fibrosis, and acute neurogenic atrophy. Based on the aggregate individual features, biopsies were assigned a histopathologic category of polymyositis, dermatomyositis, necrotizing myopathy, non-specific myositis, “acute denervation”, “fibrosis only”, or “other”. Clinical data analyzed included autoantibody profiles, scleroderma subtype and disease duration, Medsger muscle severity scores, creatine kinase (CK), electromyography (EMG), and muscle magnetic resonance imaging (MRI). Results 42 subjects (79% female and 64% diffuse scleroderma) were included in this study. Necrosis (67%), inflammation (48%), acute neurogenic atrophy (48%), and fibrosis (33%) were the most prevalent pathologic features. The presence of fibrosis was strongly associated with anti-PM-Scl antibodies. Histopathologic categories included non-specific myositis (36%), necrotizing myopathy (21%), dermatomyositis (7%), “acute denervation” (7%), “fibrosis only” (7%), and polymyositis (5%). Disease duration of scleroderma at the time of muscle biopsy was shorter in polymyositis than other histopathologic categories. Patients with anti-PM-Scl and Scl-70 antibodies also had a shorter disease duration than those with other auto-antibody profiles. Conclusion Non-specific myositis and necrotizing myopathy were the most common histopathologic categories in weak scleroderma subjects. Surprisingly, nearly half of the subjects studied had histological evidence of acute motor denervation (acute neurogenic atrophy); this has not been previously reported. Taken together, these observations suggest that a variety of pathologic mechanisms may underlie the development of

Role of Active Contraction and Tropomodulins in Regulating Actin Filament Length and Sarcomere Structure in Developing Zebrafish Skeletal Muscle.

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Mazelet, Lise; Parker, Matthew O; Li, Mei; Arner, Anders; Ashworth, Rachel

2016-01-01

Whilst it is recognized that contraction plays an important part in maintaining the structure and function of mature skeletal muscle, its role during development remains undefined. In this study the role of movement in skeletal muscle maturation was investigated in intact zebrafish embryos using a combination of genetic and pharmacological approaches. An immotile mutant line (cacnb1 (ts25) ) which lacks functional voltage-gated calcium channels (dihydropyridine receptors) in the muscle and pharmacological immobilization of embryos with a reversible anesthetic (Tricaine), allowed the study of paralysis (in mutants and anesthetized fish) and recovery of movement (reversal of anesthetic treatment). The effect of paralysis in early embryos (aged between 17 and 24 hours post-fertilization, hpf) on skeletal muscle structure at both myofibrillar and myofilament level was determined using both immunostaining with confocal microscopy and small angle X-ray diffraction. The consequences of paralysis and subsequent recovery on the localization of the actin capping proteins Tropomodulin 1 & 4 (Tmod) in fish aged from 17 hpf until 42 hpf was also assessed. The functional consequences of early paralysis were investigated by examining the mechanical properties of the larval muscle. The length-force relationship, active and passive tension, was measured in immotile, recovered and control skeletal muscle at 5 and 7 day post-fertilization (dpf). Recovery of muscle function was also assessed by examining swimming patterns in recovered and control fish. Inhibition of the initial embryonic movements (up to 24 hpf) resulted in an increase in myofibril length and a decrease in width followed by almost complete recovery in both moving and paralyzed fish by 42 hpf. In conclusion, myofibril organization is regulated by a dual mechanism involving movement-dependent and movement-independent processes. The initial contractile event itself drives the localization of Tmod1 to its sarcomeric

Leiomyoma of the sternothyroid muscle.

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Rowe, Meghan E; Khorsandi, Azita S; Guerrero, Dominick R; Brett, Elise M; Sarlin, Jonathan; Urken, Mark L

2016-01-01

Leiomyomas are benign cutaneous tumors of smooth muscle origin. Only a small percentage of leiomyomas arise in the head and neck region. We present the first case of leiomyoma arising in the sternothyroid muscle of the neck. We analyze the clinical presentation, pathology, and histology for a single case study. The histologic findings of the tumor located in the sternothyroid muscle support the diagnosis of leiomyoma. This is the first case of leiomyoma arising in the sternothyroid muscle, and only the second reported case of leiomyoma in the strap muscles of the neck. Leiomyoma should be included in the differential diagnosis of soft tissue tumors in the head and neck region. A histological analysis is essential in determining both tumor type and subtype, which will inform the proper course of treatment. Copyright © 2016 Elsevier Inc. All rights reserved.

The role of the tensor veli palatini muscle in the development of cleft palate-associated middle ear problems.

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Heidsieck, David S P; Smarius, Bram J A; Oomen, Karin P Q; Breugem, Corstiaan C

2016-09-01

Otitis media with effusion is common in infants with an unrepaired cleft palate. Although its prevalence is reduced after cleft surgery, many children continue to suffer from middle ear problems during childhood. While the tensor veli palatini muscle is thought to be involved in middle ear ventilation, evidence about its exact anatomy, function, and role in cleft palate surgery is limited. This study aimed to perform a thorough review of the literature on (1) the role of the tensor veli palatini muscle in the Eustachian tube opening and middle ear ventilation, (2) anatomical anomalies in cleft palate infants related to middle ear disease, and (3) their implications for surgical techniques used in cleft palate repair. A literature search on the MEDLINE database was performed using a combination of the keywords "tensor veli palatini muscle," "Eustachian tube," "otitis media with effusion," and "cleft palate." Several studies confirm the important role of the tensor veli palatini muscle in the Eustachian tube opening mechanism. Maintaining the integrity of the tensor veli palatini muscle during cleft palate surgery seems to improve long-term otological outcome. However, anatomical variations in cleft palate children may alter the effect of the tensor veli palatini muscle on the Eustachian tube's dilatation mechanism. More research is warranted to clarify the role of the tensor veli palatini muscle in cleft palate-associated Eustachian tube dysfunction and development of middle ear problems. Optimized surgical management of cleft palate could potentially reduce associated middle ear problems.

Synergism between abdominal and pelvic floor muscles in healthy women: a systematic review of observational studies

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Lia Ferla

Full Text Available Abstract Introduction: The training of the pelvic floor muscles is widely used for treating pelvic floor dysfunctions, like urinary incontinence. During the training, abdominal contractions are avoided; however several studies support the use of the synergy between these muscle groups. Objective: Carrying out a systematic review of studies that seek to identify the presence of synergy between the muscles of the abdomen and the pelvic floor and its functionality in women without pelvic floor dysfunction. Methodology: To conduct the review, we have followed the recommendations proposed by the Cochrane Collaboration for systematic reviews. The literature search included the databases SCIELO, PEDro, MEDLINE, Cochrane CENTRAL and EMBASE, and manual research, the starting date of the databases until August 2013. We included cross observational studies with healthy women who were assessed to find the presence of synergy between the abdominal muscles and the pelvic floor. Results: We included 10 articles and they all showed the existence of synergy between the abdominal and pelvic floor muscles in healthy women in the supine, sitting and standing positions. Conclusion: Thus, we can conclude that there is synergy between the muscles of the abdomen and the pelvic floor in healthy women. Better understanding the behavior of these muscles and synergy may favor the development of strategies for the prevention and treatment of disorders of the female pelvic floor muscles.

Agonist muscle adaptation accompanied by antagonist muscle atrophy in the hindlimb of mice following stretch-shortening contraction training.

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Rader, Erik P; Naimo, Marshall A; Ensey, James; Baker, Brent A

2017-02-02

The vast majority of dynamometer-based animal models for investigation of the response to chronic muscle contraction exposure has been limited to analysis of isometric, lengthening, or shortening contractions in isolation. An exception to this has been the utilization of a rat model to study stretch-shortening contractions (SSCs), a sequence of consecutive isometric, lengthening, and shortening contractions common during daily activity and resistance-type exercise. However, the availability of diverse genetic strains of rats is limited. Therefore, the purpose of the present study was to develop a dynamometer-based SSC training protocol to induce increased muscle mass and performance in plantarflexor muscles of mice. Young (3 months old) C57BL/6 mice were subjected to 1 month of plantarflexion SSC training. Hindlimb muscles were analyzed for muscle mass, quantitative morphology, myogenesis/myopathy relevant gene expression, and fiber type distribution. The main aim of the research was achieved when training induced a 2-fold increase in plantarflexion peak torque output and a 19% increase in muscle mass for the agonist plantaris (PLT) muscle. In establishing this model, several outcomes emerged which raised the value of the model past that of being a mere recapitulation of the rat model. An increase in the number of muscle fibers per transverse muscle section accounted for the PLT muscle mass gain while the antagonist tibialis anterior (TA) muscle atrophied by 30% with preferential atrophy of type IIb and IIx fibers. These alterations were accompanied by distinct gene expression profiles. The findings confirm the development of a stretch-shortening contraction training model for the PLT muscle of mice and demonstrate that increased cross-sectional fiber number can occur following high-intensity SSC training. Furthermore, the TA muscle atrophy provides direct evidence for the concept of muscle imbalance in phasic non-weight bearing muscles, a concept largely

Contribution of denervated muscle to contractures after neonatal brachial plexus injury: not just muscle fibrosis.

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Nikolaou, Sia; Liangjun, Hu; Tuttle, Lori J; Weekley, Holly; Christopher, Wylie; Lieber, Richard L; Cornwall, Roger

2014-03-01

We investigated the contribution of muscle fibrosis to elbow flexion contractures in a murine model of neonatal brachial plexus injury (NBPI). Four weeks after NBPI, biceps and brachialis fibrosis were assessed histologically and compared with the timing of contracture development and the relative contribution of each muscle to contractures. Modulus of elasticity and hydroxyproline (collagen) content were measured and correlated with contracture severity. The effect of halofuginone antifibrotic therapy on fibrosis and contractures was investigated. Elbow contractures preceded muscle fibrosis development. The brachialis was less fibrotic than the biceps, yet contributed more to contractures. Modulus and hydroxyproline content increased in both elbow flexors, but neither correlated with contracture severity. Halofuginone reduced biceps fibrosis but did not reduce contracture severity. Contractures after NBPI cannot be explained solely by muscle fibrosis, arguing for investigation of alternate pathophysiologic targets for contracture prevention and treatment. Copyright © 2013 Wiley Periodicals, Inc.

Synchronous monitoring of muscle dynamics and electromyogram

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Zakir Hossain, M.; Grill, Wolfgang

2011-04-01

A non-intrusive novel detection scheme has been implemented to detect the lateral muscle extension, force of the skeletal muscle and the motor action potential (EMG) synchronously. This allows the comparison of muscle dynamics and EMG signals as a basis for modeling and further studies to determine which architectural parameters are most sensitive to changes in muscle activity. For this purpose the transmission time for ultrasonic chirp signal in the frequency range of 100 kHz to 2.5 MHz passing through the muscle under observation and respective motor action potentials are recorded synchronously to monitor and quantify biomechanical parameters related to muscle performance. Additionally an ultrasonic force sensor has been employed for monitoring. Ultrasonic traducers are placed on the skin to monitor muscle expansion. Surface electrodes are placed suitably to pick up the potential for activation of the monitored muscle. Isometric contraction of the monitored muscle is ensured by restricting the joint motion with the ultrasonic force sensor. Synchronous monitoring was initiated by a software activated audio beep starting at zero time of the subsequent data acquisition interval. Computer controlled electronics are used to generate and detect the ultrasonic signals and monitor the EMG signals. Custom developed software and data analysis is employed to analyze and quantify the monitored data. Reaction time, nerve conduction speed, latent period between the on-set of EMG signals and muscle response, degree of muscle activation and muscle fatigue development, rate of energy expenditure and motor neuron recruitment rate in isometric contraction, and other relevant parameters relating to muscle performance have been quantified with high spatial and temporal resolution.

Muscle hypertrophy: a narrative review on training principles for increasing muscle mass

OpenAIRE

Howe, Louis; Read, Paul; Waldron, Mark

2017-01-01

Developing muscle cross-sectional area has the potential to enhance performance for many athletes. Because emerging evidence challenges traditional beliefs regarding the prescription of hypertrophy-focused training programs, this review provides an overview of the current literature relating, specifically, to programming variables. Evidence-based recommendations are provided for the design of effective resistance-training programs, with the goal of increasing an athlete's skeletal muscle mass.

Examining the Genetic Background of Porcine Muscle Growth and Development Based on Transcriptome and miRNAome Data

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Katarzyna Ropka-Molik

2018-04-01

Full Text Available Recently, selection in pigs has been focused on improving the lean meat content in carcasses; this focus has been most evident in breeds constituting a paternal component in breeding. Such sire-breeds are used to improve the meat quantity of cross-breed pig lines. However, even in one breed, a significant variation in the meatiness level can be observed. In the present study, the comprehensive analysis of genes and microRNA expression profiles in porcine muscle tissue was applied to identify the genetic background of meat content. The comparison was performed between whole gene expression and miRNA profiles of muscle tissue collected from two sire-line pig breeds (Pietrain, Hampshire. The RNA-seq approach allowed the identification of 627 and 416 differentially expressed genes (DEGs between pig groups differing in terms of loin weight between Pietrain and Hampshire breeds, respectively. The comparison of miRNA profiles showed differential expression of 57 microRNAs for Hampshire and 34 miRNAs for Pietrain pigs. Next, 43 genes and 18 miRNAs were selected as differentially expressed in both breeds and potentially related to muscle development. According to Gene Ontology analysis, identified DEGs and microRNAs were involved in the regulation of the cell cycle, fatty acid biosynthesis and regulation of the actin cytoskeleton. The most deregulated pathways dependent on muscle mass were the Hippo signalling pathway connected with the TGF-β signalling pathway and controlling organ size via the regulation of ubiquitin-mediated proteolysis, cell proliferation and apoptosis. The identified target genes were also involved in pathways such as the FoxO signalling pathway, signalling pathways regulating pluripotency of stem cells and the PI3K-Akt signalling pathway. The obtained results indicate molecular mechanisms controlling porcine muscle growth and development. Identified genes (SOX2, SIRT1, KLF4, PAX6 and genes belonging to the transforming growth

The effect of pneumatic tourniquets on skeletal muscle physiology.

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Patterson, S; Klenerman, L; Biswas, M; Rhodes, A

1981-01-01

The effect of 3- and 5-hour pneumatic tourniquets on skeletal muscle physiology was investigated. Maximum isometric tension development, contraction and half relaxation times were measured in the muscles lying immediately under and distal to the tourniquet. On release of the tourniquet no consistent difference between control and experimental muscles was observed with respect to contraction and half relaxation times; however, there was a marked reduction in maximum isometric tension development. On the sixth day after release of a 5-hour tourniquet, isometric tension was reduced to 2--20 per cent of the control value in the distal muscle and to 40--60 per cent of the control value in the compressed muscle. Six days after a 3-hour tourniquet the compressed muscle tension was reduced to approximately 80 per cent of the control value whilst in the distal muscle, tension development varied from normal to 64 per cent of the control value. Thus it is shown that the effect on muscle contraction after a 3-hour tourniquet is not immediately reversed by the restoration of the blood supply. A reduction in muscle strength follows which may take a week or more to recover.

Biologically inspired technologies using artificial muscles

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Bar-Cohen, Yoseph

2005-01-01

After billions of years of evolution, nature developed inventions that work, which are appropriate for the intended tasks and that last. The evolution of nature led to the introduction of highly effective and power efficient biological mechanisms that are scalable from micron to many meters in size. Imitating these mechanisms offers enormous potentials for the improvement of our life and the tools we use. Humans have always made efforts to imitate nature and we are increasingly reaching levels of advancement where it becomes significantly easier to imitate, copy, and adapt biological methods, processes and systems. Some of the biomimetic technologies that have emerged include artificial muscles, artificial intelligence, and artificial vision to which significant advances in materials science, mechanics, electronics, and computer science have contributed greatly. One of the newest fields of biomimetics is the electroactive polymers (EAP) that are also known as artificial muscles. To take advantage of these materials, efforts are made worldwide to establish a strong infrastructure addressing the need for comprehensive analytical modeling of their operation mechanism and develop effective processing and characterization techniques. The field is still in its emerging state and robust materials are not readily available however in recent years significant progress has been made and commercial products have already started to appear. This paper covers the state-of-the-art and challenges to making artificial muscles and their potential biomimetic applications.

Overview of the Muscle Cytoskeleton

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Henderson, Christine A.; Gomez, Christopher G.; Novak, Stefanie M.; Mi-Mi, Lei; Gregorio, Carol C.

2018-01-01

Cardiac and skeletal striated muscles are intricately designed machines responsible for muscle contraction. Coordination of the basic contractile unit, the sarcomere, and the complex cytoskeletal networks are critical for contractile activity. The sarcomere is comprised of precisely organized individual filament systems that include thin (actin), thick (myosin), titin, and nebulin. Connecting the sarcomere to other organelles (e.g., mitochondria and nucleus) and serving as the scaffold to maintain cellular integrity are the intermediate filaments. The costamere, on the other hand, tethers the sarcomere to the cell membrane. Unique structures like the intercalated disc in cardiac muscle and the myotendinous junction in skeletal muscle help synchronize and transmit force. Intense investigation has been done on many of the proteins that make up these cytoskeletal assemblies. Yet the details of their function and how they interconnect have just started to be elucidated. A vast number of human myopathies are contributed to mutations in muscle proteins; thus understanding their basic function provides a mechanistic understanding of muscle disorders. In this review, we highlight the components of striated muscle with respect to their interactions, signaling pathways, functions, and connections to disease. PMID:28640448

Cellular and molecular mechanisms of muscle atrophy

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Paolo Bonaldo

2013-01-01

Full Text Available Skeletal muscle is a plastic organ that is maintained by multiple pathways regulating cell and protein turnover. During muscle atrophy, proteolytic systems are activated, and contractile proteins and organelles are removed, resulting in the shrinkage of muscle fibers. Excessive loss of muscle mass is associated with poor prognosis in several diseases, including myopathies and muscular dystrophies, as well as in systemic disorders such as cancer, diabetes, sepsis and heart failure. Muscle loss also occurs during aging. In this paper, we review the key mechanisms that regulate the turnover of contractile proteins and organelles in muscle tissue, and discuss how impairments in these mechanisms can contribute to muscle atrophy. We also discuss how protein synthesis and degradation are coordinately regulated by signaling pathways that are influenced by mechanical stress, physical activity, and the availability of nutrients and growth factors. Understanding how these pathways regulate muscle mass will provide new therapeutic targets for the prevention and treatment of muscle atrophy in metabolic and neuromuscular diseases.

Muscle dysfunction in cancer patients

DEFF Research Database (Denmark)

Christensen, Jesper Frank; Jones, L W; Andersen, J L

2014-01-01

dysfunction in cancer patients lies in the correlation to vital clinical end points such as cancer-specific and all-cause mortality, therapy complications and quality of life (QoL). Such associations strongly emphasize the need for effective therapeutic countermeasures to be developed and implemented...... implications of muscle dysfunction in cancer patients. The efficacy of exercise training to prevent and/or mitigate cancer-related muscle dysfunction is also discussed. DESIGN: We identified 194 studies examining muscular outcomes in cancer patients by searching PubMed and EMBASE databases. RESULTS: Muscle...... dysfunction is evident across all stages of the cancer trajectory. The causes of cancer-related muscle dysfunction are complex, but may involve a wide range of tumor-, therapy- and/or lifestyle-related factors, depending on the clinical setting of the individual patient. The main importance of muscle...

Skeletal muscle cutpoints associated with elevated physical disability risk in older men and women.

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Janssen, Ian; Baumgartner, Richard N; Ross, Robert; Rosenberg, Irwin H; Roubenoff, Ronenn

2004-02-15

The purpose of this study was to determine skeletal muscle cutpoints for identifying elevated physical disability risk in older adults. Subjects included 4,449 older (> or = 60 years) participants from the Third National Health and Nutrition Examination Survey during 1988-1994. Physical disability was assessed by questionnaire, and bioimpedance was used to estimate skeletal muscle, which was normalized for height. Receiver operating characteristics were used to develop the skeletal muscle cutpoints associated with a high likelihood of physical disability. Odds for physical disability were compared in subjects whose measures fell above and below these cutpoints. Skeletal muscle cutpoints of 5.76-6.75 and values in men were 8.51-10.75 and skeletal muscle values, women with moderate- and high-risk skeletal muscle values had odds for physical disability of 1.41 (95% confidence interval (CI): 0.97, 2.04) and 3.31 (95% CI: 1.91, 5.73), respectively. The corresponding odds in men were 3.65 (95% CI: 1.92, 6.94) and 4.71 (95% CI: 2.28, 9.74). This study presents skeletal muscle cutpoints for physical disability risk in older adults. Future applications of these cutpoints include the comparison of morbidity risk in older persons with normal muscle mass and those with sarcopenia, the determination and comparison of sarcopenia prevalences, and the estimation of health-care costs attributable to sarcopenia.

Muscle MRI findings in facioscapulohumeral muscular dystrophy

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Gerevini, Simonetta; Caliendo, Giandomenico; Falini, Andrea [IRCCS San Raffaele Scientific Institute, Neuroradiology Unit, Head and Neck Department, Milan (Italy); Scarlato, Marina; Previtali, Stefano Carlo [IRCCS San Raffaele Scientific Institute, Department of Neurology, INSPE and Division of Neuroscience, Milan (Italy); Maggi, Lorenzo; Pasanisi, Barbara; Morandi, Lucia [Fondazione IRCCS Istituto Neurologico ' ' Carlo Besta' ' , Neuromuscular Diseases and Neuroimmunology Unit, Milan (Italy); Cava, Mariangela [IRCCS San Raffaele Scientific Institute, Department of Radiology and Center for Experimental Imaging, Milan (Italy)

2016-03-15

Facioscapulohumeral muscular dystrophy (FSHD) is characterized by extremely variable degrees of facial, scapular and lower limb muscle involvement. Clinical and genetic determination can be difficult, as molecular analysis is not always definitive, and other similar muscle disorders may have overlapping clinical manifestations. Whole-body muscle MRI examination for fat infiltration, atrophy and oedema was performed to identify specific patterns of muscle involvement in FSHD patients (30 subjects), and compared to a group of control patients (23) affected by other myopathies (NFSHD). In FSHD patients, we detected a specific pattern of muscle fatty replacement and atrophy, particularly in upper girdle muscles. The most frequently affected muscles, including paucisymptomatic and severely affected FSHD patients, were trapezius, teres major and serratus anterior. Moreover, asymmetric muscle involvement was significantly higher in FSHD as compared to NFSHD patients. In conclusion, muscle MRI is very sensitive for identifying a specific pattern of involvement in FSHD patients and in detecting selective muscle involvement of non-clinically testable muscles. Muscle MRI constitutes a reliable tool for differentiating FSHD from other muscular dystrophies to direct diagnostic molecular analysis, as well as to investigate FSHD natural history and follow-up of the disease. (orig.)

Botulinum toxin injection causes hyper-reflexia and increased muscle stiffness of the triceps surae muscle in the rat

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Pingel, Jessica; Wienecke, Jacob; Lorentzen, Jakob

2016-01-01

Botulinum toxin is used to diminish spasticity and reduce the risk of development of contractures. Here, we investigated changes in muscle stiffness caused by reflex activity or elastic muscle properties following botulinum toxin injection in the triceps surae muscle in rats. Forty-four rats...... received injection of botulinum toxin in the left triceps surae muscle. Control measurements were performed on the non-injected contralateral side in all rats. Acute experiments were performed 1, 2, 4 and 8 weeks following injection. The triceps surae muscle was dissected free, the Achilles tendon was cut...... and attached to a muscle puller. The resistance of the muscle to stretches of different amplitudes and velocities was systematically investigated. Reflex mediated torque was normalized to the maximal muscle force (Mmax) evoked by supramaximal stimulation of the tibial nerve. Botulinum toxin injection caused...

Accumulation of ceramide in slow-twitch muscle contributes to the development of insulin resistance in the obese JCR:LA-cp rat.

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Fillmore, Natasha; Keung, Wendy; Kelly, Sandra E; Proctor, Spencer D; Lopaschuk, Gary D; Ussher, John R

2015-06-01

What is the central question of this study? The aim was to determine whether the accumulation of ceramide contributes to skeletal muscle insulin resistance in the JCR obese rat. What is the main finding and its importance? Our main new finding is that ceramides accumulate only in slow-twitch skeletal muscle in the JCR obese rat and that reducing ceramide content in this muscle type by inhibition of serine palmitoyl transferase-1 halts the progression of insulin resistance in this rat model predisposed to early development of type 2 diabetes. Our findings highlight the importance of assessing insulin signalling/sensitivity and lipid intermediate accumulation in different muscle fibre types. It has been postulated that insulin resistance results from the accumulation of cytosolic lipid metabolites (i.e. diacylglycerol/ceramide) that impede insulin signalling and impair glucose homeostasis. De novo ceramide synthesis is catalysed by serine palmitoyl transferase-1. Our aim was to determine whether de novo ceramide synthesis plays a role during development of insulin resistance in the JCR:LA-cp obese rat. Ten-week-old JCR:LA-cp obese rats were supplemented with either vehicle or the serine palmitoyl transferase-1 inhibitor l-cycloserine (360 mg l(-1) ) in their drinking water for a 2 week period, and glycaemia was assessed by meal tolerance testing. Treatment of JCR:LA-cp obese rats with l-cycloserine improved their plasma glucose and insulin levels during a meal tolerance test. Examination of muscle lipid metabolites and protein phosphorylation patterns revealed differential signatures in slow-twitch (soleus) versus fast-twitch muscle (gastrocnemius), in that ceramide levels were increased in soleus but not gastrocnemius muscles of JCR:LA-cp obese rats. Likewise, improved glycaemia in l-cycloserine-treated JCR:LA-cp obese rats was associated with enhanced Akt and pyruvate dehydrogenase signalling in soleus but not gastrocnemius muscles, probably as a result of l

Selective reversal of muscle relaxation in general anesthesia: focus on sugammadex

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Sorin J Brull

2009-04-01

Full Text Available Sorin J Brull1, Mohamed Naguib21Department of Anesthesiology, Mayo Clinic College of Medicine, Mayo Clinic Hospital, Jacksonville, FL, USA; 2Department of Anesthesiology and Pain Medicine, The University of Texas M D Anderson Cancer Center,  Houston, TX, USAAbstract: Despite the significant improvements in the pharmacology of muscle relaxants in the past six decades, the search for the ideal muscle relaxant continues, mainly because of the incomplete efficacy and persistent side effects associated with their antagonism. Clinical concerns remain about the residual paralysis and hemodynamic side effects associated with the classic pharmacologic reversal agents, the acetylcholinesterase inhibitors. Although the development of the “ideal muscle relaxant” remains illusory, pharmacologic advancements hold promise for improved clinical care and patient safety. Recent clinical advances include the development of short-acting nondepolarizing muscle relaxant agents that have fast onset and a very rapid metabolism that allows reliable and complete recovery; and the development of selective, “designer” reversal agents that are specific for a single drug or class of drugs. This article reviews recent developments in the pharmacology of these selective reversal agents: plasma cholinesterases, cysteine, and sugammadex. Although each of the selective reversal agents is specific in its substrate, the clinical use of the combination of muscle relaxant with its specific reversal agent will allow much greater intraoperative titrating ability, decreased side effect profile, and may result in a decreased incidence of postoperative residual paralysis and improved patient safety.Keywords: selective reversal agents, cysteine, plasma cholinesterases, sugammadex

Exercise Promotes Healthy Aging of Skeletal Muscle

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Cartee, Gregory D; Hepple, Russell T; Bamman, Marcas M

2016-01-01

caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial...... respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes "healthy aging" by inducing modifications in skeletal muscle....

Development of Ankle Foot Orthosis (AFO Using Pneumatic Artificial Muscle for Disabled Children

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Ishak N.Z.

2017-01-01

Full Text Available Ankle foot orthosis (AFO are commonly used to correct the instabilities and joint weakness of lower limb. In this research, AFO was developed by using pneumatic artificial muscle (PAM to prevent plantarflexion to occur and also to correct the foot from the inversion syndrome. The research started with designing the AFO by using SolidWorks software based on anthropometry measurement data (n=5, age=12 years old. The mechanical simulation was conducted by using Autodesk Inventor software to obtain a safety factor before the fabrication process was conducted. The AFO was fabricated using 3D printer and the thermoplastic elastomer (TPE rubber was selected as the material. PAM was tested by using test bed machine to generate the force and contraction by muscle. The result shows that the PAM was suitable for low speed as the displacement was greater. The AFO could be valuable for the gait rehabilitation.

Electrically and hybrid-induced muscle activations: effects of muscle size and fiber type

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Kelly Stratton

2016-07-01

Full Text Available The effect of three electrical stimulation (ES frequencies (10, 35, and 50 Hz on two muscle groups with different proportions of fast and slow twitch fibers (abductor pollicis brevis (APB and vastus lateralis (VL was explored. We evaluated the acute muscles’ responses individually and during hybrid activations (ES superimposed by voluntary activations. Surface electromyography (sEMG and force measurements were evaluated as outcomes. Ten healthy adults (mean age: 24.4 ± 2.5 years participated after signing an informed consent form approved by the university Institutional Review Board. Protocols were developed to: 1 compare EMG activities during each frequency for each muscle when generating 25% Maximum Voluntary Contraction (MVC force, and 2 compare EMG activities during each frequency when additional voluntary activation was superimposed over ES-induced 25% MVC to reach 50% and 75% MVC. Empirical mode decomposition (EMD was utilized to separate ES artifacts from voluntary muscle activation. For both muscles, higher stimulation frequency (35 and 50Hz induced higher electrical output detected at 25% of MVC, suggesting more recruitment with higher frequencies. Hybrid activation generated proportionally less electrical activity than ES alone. ES and voluntary activations appear to generate two different modes of muscle recruitment. ES may provoke muscle strength by activating more fatiguing fast acting fibers, but voluntary activation elicits more muscle coordination. Therefore, during the hybrid activation, less electrical activity may be detected due to recruitment of more fatigue-resistant deeper muscle fibers, not reachable by surface EMG.

The Bone-Muscle Relationship in Men and Women

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Thomas F. Lang

2011-01-01

Full Text Available Muscle forces are a strong determinant of bone structure, particularly during the process of growth and development. The gender divergence in the bone-muscle relationship becomes strongly evident during adolescence. In females, growth is characterized by increased estrogen levels and increased mass and strength of bone relative to that of muscle, whereas in men, increases in testosterone fuel large increases in muscle, resulting in muscle forces that coincide with a large growth in bone dimensions and strength. In adulthood, significant age-related losses are observed for both bone and muscle tissues. Large decrease in estrogen levels in women appears to diminish the skeleton's responsiveness to exercise more than in men. In contrast, the aging of the muscle-bone axis in men is a function of age related declines in both hormones. In addition to the well-known age related changes in the mechanical loading of bone by muscle, newer studies appear to provide evidence of age- and gender-related variations in molecular signaling between bone and muscle that are independent of purely mechanical interactions. In summary, gender differences in the acquisition and age-related loss in bone and muscle tissues may be important for developing gender-specific strategies for using exercise to reduce bone loss with aging.

SMASH - semi-automatic muscle analysis using segmentation of histology: a MATLAB application.

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Smith, Lucas R; Barton, Elisabeth R

2014-01-01

Histological assessment of skeletal muscle tissue is commonly applied to many areas of skeletal muscle physiological research. Histological parameters including fiber distribution, fiber type, centrally nucleated fibers, and capillary density are all frequently quantified measures of skeletal muscle. These parameters reflect functional properties of muscle and undergo adaptation in many muscle diseases and injuries. While standard operating procedures have been developed to guide analysis of many of these parameters, the software to freely, efficiently, and consistently analyze them is not readily available. In order to provide this service to the muscle research community we developed an open source MATLAB script to analyze immunofluorescent muscle sections incorporating user controls for muscle histological analysis. The software consists of multiple functions designed to provide tools for the analysis selected. Initial segmentation and fiber filter functions segment the image and remove non-fiber elements based on user-defined parameters to create a fiber mask. Establishing parameters set by the user, the software outputs data on fiber size and type, centrally nucleated fibers, and other structures. These functions were evaluated on stained soleus muscle sections from 1-year-old wild-type and mdx mice, a model of Duchenne muscular dystrophy. In accordance with previously published data, fiber size was not different between groups, but mdx muscles had much higher fiber size variability. The mdx muscle had a significantly greater proportion of type I fibers, but type I fibers did not change in size relative to type II fibers. Centrally nucleated fibers were highly prevalent in mdx muscle and were significantly larger than peripherally nucleated fibers. The MATLAB code described and provided along with this manuscript is designed for image processing of skeletal muscle immunofluorescent histological sections. The program allows for semi-automated fiber detection

Endocrine regulation of fetal skeletal muscle growth: impact on future metabolic health

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Brown, Laura D.

2014-01-01

Establishing sufficient skeletal muscle mass is essential for lifelong metabolic health. The intrauterine environment is a major determinant of the muscle mass that is present for the life course of an individual, because muscle fiber number is set at the time of birth. Thus, a compromised intrauterine environment from maternal nutrient restriction or placental insufficiency that restricts development of muscle fiber number can have permanent effects on the amount of muscle an individual will live with. Reduced muscle mass due to fewer muscle fibers persists even after compensatory or “catch up” postnatal growth occurs. Furthermore, muscle hypertrophy can only partially compensate for this limitation in fiber number. Compelling associations link low birth weight and decreased muscle mass to future insulin resistance, which can drive the development of the metabolic syndrome and type 2 diabetes, and risk for cardiovascular events later in life. There are gaps in knowledge about the origins of reduced muscle growth at the cellular level and how these patterns are set during fetal development. By understanding the nutrient and endocrine regulation of fetal skeletal muscle growth and development, we can direct research efforts towards improving muscle growth early in life in order to prevent the development of chronic metabolic disease later in life. PMID:24532817

Effect of brief daily resistance training on rapid force development in painful neck and shoulder muscles

DEFF Research Database (Denmark)

Jay, Kenneth; Schraefel, Mc; Andersen, Christoffer H

2013-01-01

OBJECTIVE: To determine the effect of small daily amounts of progressive resistance training on rapid force development of painful neck/shoulder muscles. METHODS: 198 generally healthy adults with frequent neck/shoulder muscle pain (mean: age 43.1 years, computer use 93% of work time, 88% women......, duration of pain 186 day during the previous year) were randomly allocated to 2- or 12 min of daily progressive resistance training with elastic tubing or to a control group receiving weekly information on general health. A blinded assessor took measures at baseline and at 10-week follow-up; participants.......05) for both training groups. Maximal muscle strength increased only ~5-6% [mean and 95% confidence interval for 2- and 12-min groups to control, respectively: 2.5 Nm (0.05-0.73) and 2.2 Nm (0.01-0.70)]. No significant differences between the 2- and 12-min groups were evident. A weak but significant...

Optimization measurement of muscle oxygen saturation under isometric studies using FNIRS

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Halim, A. A. A.; Laili, M. H.; Salikin, M. S.; Rusop, M.

2018-05-01

Development of functional near infrared spectroscopy (fNIRS) technologies has advanced quantification signal using multiple wavelength and detector to investigate hemodynamic response in human muscle. These non-invasive technologies have been widely used to solve the propagation of light inside the tissues including the absorption, scattering coefficient and to quantify the oxygenation level of haemoglobin and myoglobin in human muscle. The goal of this paper is to optimize the measurement of muscle oxygen saturation during isometric exercise using functional near infrared spectroscopy (fNIRS). The experiment was carried out on 15 sedentary healthy male volunteers. All volunteers are required to perform an isometric exercise at three assessment of muscular fatigue's level on flexor digitalis (FDS) muscle in the human forearm using fNIRS. The slopes of the signals have been highlighted to evaluate the muscle oxygen saturation of regional muscle fatigue. As a result, oxygen saturation slope from 10% exercise showed steeper than the first assessment at 30%-50% of fatigues level. The hemodynamic signal response showed significant value (p=0.04) at all three assessment of muscular fatigue's level which produce a p-value (p<0.05) measured by fNIRS. Thus, this highlighted parameter could be used to estimate fatigue's level of human and could open other possibilities to study muscle performance diagnosis.

EFFECT OF MUSCLE ENERGY TECHNIQUE ON FLEXIBILITY OF HAMSTRING AND CALF MUSCLES AND SPRINTING PERFORMANCE IN SPRINTERS

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M. Prasad Naik

2015-10-01

Full Text Available Background: Muscle energy technique is used for restoring normal tone in hypertonic muscles, strengthening weak muscles, preparing muscle for subsequent stretching, one of the main uses of this method is to normalize joint range which may help in increase flexibility and performance in sprinters. The aim of the study is to evaluate the effect of muscle energy technique on flexibility of hamstrings and calf muscles and sprinting performance in sprinters. The objective of the study is to determine the muscle energy technique on hamstrings and calf muscle flexibility and sprinting performance in sprinters by using goniometer and timing of sprinting performance. Method: The study design is an experimental study in which 30 male sprinters were recruited in this study. The study sample included all male healthy sprinters, aged between 15 -30 years. All subjects received warm up, muscle energy technique and cool down exercises daily for a period of 6weeks.The outcome measures are 90°-90°popliteal angle for assessing hamstring flexibility and ROM of ankle joint for calf muscles by universal goniometer and sprinting performance time by using stopwatch. Results: Independent t-test and paired t- test are used to analyse the data. A significant difference was found between pre and post values of hamstring and calf muscle flexibility and sprinting performance after the analysis in this study. Conclusion: This study shows that there was a significant effect of MET on hamstring and calf muscle flexibility and sprinting performance.

[Nosological classification and assessment of muscle dysmorphia].

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Babusa, Bernadett; Túry, Ferenc

2011-01-01

Muscle dysmorphia is a recently described psychiatric disorder, characterized by a pathological preoccupation with muscle size. In spite of their huge muscles, muscle dysmorphia sufferers believe that they are insufficiently large and muscular therefore would like to be bigger and more muscular. Male bodybuilders are at high-risk for the disorder. The nosological classification of muscle dysmorphia has been changed over the years. However, consensus has not emerged so far. Most of the ongoing debate has conceptualized muscle dysmorphia as an eating disorder, obsessive-compulsive disorder and body dysmorphic disorder. There are a number of arguments for and againts. In the present study the authors do not take a position on the diagnostic classification of muscle dysmorphia. The purpose of the study is to review the present approaches relating to the diagnostic classification of muscle dysmporphia. Many different questionnaires were developed for the assessment of muscle dysmorphia. Currently, there is a lack of assessment methods measuring muscle dysmorphia symptoms in Hungary. As a secondary purpose the study also presents the Hungarian version of the Muscle Appearance Satisfaction Scale (Mayville et al., 2002).

Expression patterns of regulatory RNAs, including lncRNAs and tRNAs, during postnatal growth of normal and dystrophic (mdx) mouse muscles, and their response to taurine treatment.

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Butchart, Lauren C; Terrill, Jessica R; Rossetti, Giulia; White, Robert; Filipovska, Aleksandra; Grounds, Miranda D

2018-06-01

Post-natal skeletal muscle growth in mice is very rapid and involves complex changes in many cells types over the first 6 weeks of life. The acute onset of dystropathology also occurs around 3 weeks of age in the mdx mouse model of the human disease Duchenne Muscular Dystrophy (DMD). This study investigated (i) alterations in expression patterns of regulatory non-coding RNAs (ncRNAs) in vivo, including miRNAs, lncRNAs and tRNAs, during early growth of skeletal muscles in normal control C57Bl/10Scsn (C57) compared with dystrophic mdx mice from 2 to 6 weeks of postnatal age, and revealed inherent differences in vivo for levels of 3 ncRNAs between C57 and mdx muscles before the onset of dystropathology. Since the amino acid taurine has many benefits and reduces disease severity in mdx mice, this study also (ii) determined the impact of taurine treatment on these expression patterns in mdx muscles at the onset of dystropathology (3 weeks) and after several bouts of myonecrosis and regeneration (6 weeks). Taurine treatment of mdx mice only altered ncRNA levels when administered from 18 days to 6 weeks of age, but a deficiency in tRNA levels was rectified earlier in mdx skeletal muscles treated from 14 days to 3 weeks. Myogenesis in tissue culture was also used to (iii) compare ncRNA expression patterns for both strains, and (iv) the response to taurine treatment. These analyses revealed intrinsic differences in ncRNA expression patterns during myogenesis between strains, as well as increased sensitivity of mdx ncRNA levels to taurine treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.

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Abe, Takashi; Loenneke, Jeremy P; Fahs, Christopher A; Rossow, Lindy M; Thiebaud, Robert S; Bemben, Michael G

2012-07-01

Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise. © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Contracture of Slow Striated Muscle during Calcium Deprivation

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Irwin, Richard L.; Hein, Manfred M.

1963-01-01

When deprived of calcium the slow striated muscle fibers of the frog develop reversible contractures in either hypertonic or isotonic solutions. While calcium deprivation continues because of a flowing calcium-free solution the muscles relax slowly and completely. Restoration of calcium during contracture relaxes the muscle promptly to initial tension. When relaxed during calcium lack the return of calcium does not change tension and the muscle stays relaxed. When contractures are induced by solutions containing small amounts of calcium relaxation does not occur or requires several hours. The rate of tension development depends upon the rate at which calcium moves outward since the contractures develop slower in low concentrations of calcium and are absent or greatly slowed in a stagnant calcium-free solution. Withdrawal of calcium prevents the contractile responses to ACh, KCl, or electrical stimulation through the nerve. Muscles return to their original excitability after calcium is restored. Origin of the contractures is unrelated to nerve activity since they are maximal during transmission failure from calcium lack, occur in denervated muscles, and are not blocked by high concentrations of d-tubocurarine, procaine, or atropine. The experiments also indicate that the contractures do not originate from repetitive activity of muscle membranes. The findings are most simply explained by relating the outward movement of calcium as a link for initiating contraction in slow type striated muscle. PMID:14065284

Expression and function of the SDF-1 chemokine receptors CXCR4 and CXCR7 during mouse limb muscle development and regeneration.

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Hunger, Conny; Ödemis, Veysel; Engele, Jürgen

2012-10-15

The chemokine, SDF-1/CXCL12, and its receptor, CXCR4, have been implied to play major roles during limb myogenesis. This concept was recently challenged by the identification of CXCR7 as an alternative SDF-1 receptor, which can either act as a scavenger receptor, a modulator of CXCR4, or an active chemokine receptor. We have now re-examined this issue by determining whether SDF-1 would signal to C2C12 myoblasts and subsequently influence their differentiation via CXCR4 and/or CXCR7. In addition, we have analyzed CXCR7, CXCR4, and SDF-1 expression in developing and injured mouse limb muscles. We demonstrate that in undifferentiated C2C12 cells, SDF-1-dependent cell signaling and resulting inhibitory effects on myogenic differentiation are entirely mediated by CXCR4. We further demonstrate that CXCR7 expression increases in differentiating C2C12 cells, which in turn abrogates CXCR4 signaling. Moreover, consistent with the view that CXCR4 and CXCR7 control limb myogenesis in vivo by similar mechanisms, we found that CXCR4 expression is the highest in late embryonic hindlimb muscles and drops shortly after birth when secondary muscle growth terminates. Vice versa, CXCR7 expression increased perinatally and persisted into adult life. Finally, underscoring the role of the SDF-1 system in muscle regeneration, we observed that SDF-1 is continuously expressed by endomysial cells of postnatal and adult muscle fibers. Analysis of dystrophin-deficient mdx mice additionally revealed that muscle regeneration is associated with muscular re-expression of CXCR4. The apparent tight control of limb muscle development and regeneration by CXCR4 and CXCR7 points to these chemokine receptors as promising therapeutic targets for certain muscle disorders. Copyright © 2012 Elsevier Inc. All rights reserved.

Sheep skeletal muscle transcriptome analysis reveals muscle growth regulatory lncRNAs.

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Chao, Tianle; Ji, Zhibin; Hou, Lei; Wang, Jin; Zhang, Chunlan; Wang, Guizhi; Wang, Jianmin

2018-01-01

As widely distributed domestic animals, sheep are an important species and the source of mutton. In this study, we aimed to evaluate the regulatory lncRNAs associated with muscle growth and development between high production mutton sheep (Dorper sheep and Qianhua Mutton Merino sheep) and low production mutton sheep (Small-tailed Han sheep). In total, 39 lncRNAs were found to be differentially expressed. Using co-expression analysis and functional annotation, 1,206 co-expression interactions were found between 32 lncRNAs and 369 genes, and 29 of these lncRNAs were found to be associated with muscle development, metabolism, cell proliferation and apoptosis. lncRNA-mRNA interactions revealed 6 lncRNAs as hub lncRNAs. Moreover, three lncRNAs and their associated co-expressed genes were demonstrated by cis-regulatory gene analyses, and we also found a potential regulatory relationship between the pseudogene lncRNA LOC101121401 and its parent gene FTH1. This study provides a genome-wide resolution of lncRNA and mRNA regulation in muscles from mutton sheep.

Immunology Guides Skeletal Muscle Regeneration

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F. Andrea Sass

2018-03-01

Full Text Available Soft tissue trauma of skeletal muscle is one of the most common side effects in surgery. Muscle injuries are not only caused by accident-related injuries but can also be of an iatrogenic nature as they occur during surgical interventions when the anatomical region of interest is exposed. If the extent of trauma surpasses the intrinsic regenerative capacities, signs of fatty degeneration and formation of fibrotic scar tissue can occur, and, consequentially, muscle function deteriorates or is diminished. Despite research efforts to investigate the physiological healing cascade following trauma, our understanding of the early onset of healing and how it potentially determines success or failure is still only fragmentary. This review focuses on the initial physiological pathways following skeletal muscle trauma in comparison to bone and tendon trauma and what conclusions can be drawn from new scientific insights for the development of novel therapeutic strategies. Strategies to support regeneration of muscle tissue after injury are scarce, even though muscle trauma has a high incidence. Based on tissue specific differences, possible clinical treatment options such as local immune-modulatory and cell therapeutic approaches are suggested that aim to support the endogenous regenerative potential of injured muscle tissues.

Role of active contraction and tropomodulins in regulating actin filament length and sarcomere structure in developing zebrafish skeletal muscle

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Lise eMazelet

2016-03-01

Full Text Available Whilst it is recognised that contraction plays an important part in maintaining the structure and function of mature skeletal muscle, its role during development remains undefined. In this study the role of movement in skeletal muscle maturation was investigated in intact zebrafish embryos using a combination of genetic and pharmacological approaches. An immotile mutant line (cacnb1ts25 which lacks functional voltage-gated calcium channels (dihydropyridine receptors in the muscle and pharmacological immobilisation of embryos with a reversible anaesthetic (Tricaine, allowed the study of paralysis (in mutants and anaesthetised fish and recovery of movement (reversal of anaesthetic treatment. The effect of paralysis in early embryos (aged between 17-24 hours post fertilisation, hpf on skeletal muscle structure at both myofibrillar and myofilament level was determined using both immunostaining with confocal microscopy and small angle X-ray diffraction. The consequences of paralysis and subsequent recovery on the localisation of the actin capping proteins Tropomodulin 1 &4 (Tmod in fish aged from 17hpf until 42hpf was also assessed. The functional consequences of early paralysis were investigated by examining the mechanical properties of the larval muscle. The length-force relationship, active and passive tension, was measured in immotile, recovered and control skeletal muscle at 5 and 7 day post fertilisation (dpf. Recovery of muscle function was also assessed by examining swimming patterns in recovered and control fish. Inhibition of the initial embryonic movements (up to 24 hpf resulted in an increase in myofibril length and a decrease in width followed by almost complete recovery in both moving and paralysed fish by 42hpf. In conclusion, myofibril organisation is regulated by a dual mechanism involving movement-dependent and movement-independent processes. The initial contractile event itself drives the localisation of Tmod1 to its sarcomeric

STAT3 Activation in Skeletal Muscle Links Muscle Wasting and the Acute Phase Response in Cancer Cachexia

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Kunzevitzky, Noelia; Guttridge, Denis C.; Khuri, Sawsan; Koniaris, Leonidas G.; Zimmers, Teresa A.

2011-01-01

Background Cachexia, or weight loss despite adequate nutrition, significantly impairs quality of life and response to therapy in cancer patients. In cancer patients, skeletal muscle wasting, weight loss and mortality are all positively associated with increased serum cytokines, particularly Interleukin-6 (IL-6), and the presence of the acute phase response. Acute phase proteins, including fibrinogen and serum amyloid A (SAA) are synthesized by hepatocytes in response to IL-6 as part of the innate immune response. To gain insight into the relationships among these observations, we studied mice with moderate and severe Colon-26 (C26)-carcinoma cachexia. Methodology/Principal Findings Moderate and severe C26 cachexia was associated with high serum IL-6 and IL-6 family cytokines and highly similar patterns of skeletal muscle gene expression. The top canonical pathways up-regulated in both were the complement/coagulation cascade, proteasome, MAPK signaling, and the IL-6 and STAT3 pathways. Cachexia was associated with increased muscle pY705-STAT3 and increased STAT3 localization in myonuclei. STAT3 target genes, including SOCS3 mRNA and acute phase response proteins, were highly induced in cachectic muscle. IL-6 treatment and STAT3 activation both also induced fibrinogen in cultured C2C12 myotubes. Quantitation of muscle versus liver fibrinogen and SAA protein levels indicates that muscle contributes a large fraction of serum acute phase proteins in cancer. Conclusions/Significance These results suggest that the STAT3 transcriptome is a major mechanism for wasting in cancer. Through IL-6/STAT3 activation, skeletal muscle is induced to synthesize acute phase proteins, thus establishing a molecular link between the observations of high IL-6, increased acute phase response proteins and muscle wasting in cancer. These results suggest a mechanism by which STAT3 might causally influence muscle wasting by altering the profile of genes expressed and translated in muscle such

Thigh muscle volume predicted by anthropometric measurements and correlated with physical function in the older adults.

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Chen, B B; Shih, T T F; Hsu, C Y; Yu, C W; Wei, S Y; Chen, C Y; Wu, C H; Chen, C Y

2011-06-01

(1) to correlate thigh muscle volume measured by magnetic resonance image (MRI) with anthropometric measurements and physical function in elderly subjects; (2) to predict MRI-measured thigh muscle volume using anthropometric measurements and physical functional status in elderly subjects. Cross-sectional, nonrandomized study. Outpatient clinic in Taiwan. Sixty-nine elderly subjects (33 men and 36 women) aged 65 and older. The anthropometric data (including body height, body weight, waist size, and thigh circumference), physical activity and function (including grip strength, bilateral quadriceps muscle power, the up and go test, chair rise, and five meters walk time) and bioelectrical impedance analysis data (including total body fat mass, fat-free mass, and predictive muscle size) were measured. MRI-measured muscle volume of both thighs was used as the reference standard. The MRI-measured thigh volume was positively correlated with all anthropometric data, quadriceps muscle power and the up and go test as well as fat-free mass and predictive muscle mass, whereas it was negatively associated with age and walk time. In predicting thigh muscle volume, the variables of age, gender, body weight, and thigh circumference were significant predictors in the linear regression model: Muscle volume (cm3) =4226.3－42.5 × Age (year)－955.7 × gender (male=1, female=2) + 45.9 × body weight(kg) + 60.0 × thigh circumference (cm) (r2 = 0.745, P estimate = 581.6 cm3). The current work provides evidence of a strong relationship between thigh muscle volume and physical function in the elderly. We also developed a prediction equation model using anthropometric measurements. This model is a simple and noninvasive method for everyday clinical practice and follow-up.

Effect of muscle acidity on muscle metabolism and fatigue during intense exercise in man

DEFF Research Database (Denmark)

Bangsbo, Jens; Madsen, K.; Kiens, Bente

1996-01-01

1. The aim of this study was to examine the effect of muscle pH on muscle metabolism and development of fatigue during intense exercise. 2. Seven subjects performed intense exhaustive leg exercise on two occasions: with and without preceding intense intermittent arm exercise leading to high...... or moderate (control) blood lactate concentrations (HL and C, respectively). Prior to and immediately after each exercise bout, a muscle biopsy was taken from m. vastus lateralis of the active leg. Leg blood flow was measured and femoral arterial and venous blood samples were collected before and frequently...... during the exhaustive exercises. 3. The duration of the exercise was shorter in HL than in C (3.46 +/- 0.28 vs. 4.67 +/- 0.55 min; means +/- S.E.M.; P muscle pH was the same in C and HL (7.17 vs. 7.10), but at the end of exercise muscle pH was lower in HL than in C (6.82 vs. 6...

Naturally Protected Muscle Phenotypes: Development of Novel Treatment Strategies for Duchenne Muscular Dystrophy

OpenAIRE

Dowling, Paul; Doran, Philip; Lohan, James; Culligan, Kevin; Ohlendieck, Kay

2004-01-01

Primary abnormalities in the dystrophin gene underlie x-linked muscular dystrophy. However, the absence of the dystrophin isoform Dp427 does not necessarily result in a severe dystrophic phenotype in all muscle groups. Distal mdx muscles, namely extraocular and toe fibres, appear to represent a protected phenotype in muscular dystrophy. Thus, a comparative analysis of affected versus naturally protected muscle cells should lead to a greater knowledge of the molecular pathogenes...

Skeletal Muscle Cell Induction from Pluripotent Stem Cells

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Yusaku Kodaka

2017-01-01

Full Text Available Embryonic stem cells (ESCs and induced pluripotent stem cells (iPSCs have the potential to differentiate into various types of cells including skeletal muscle cells. The approach of converting ESCs/iPSCs into skeletal muscle cells offers hope for patients afflicted with the skeletal muscle diseases such as the Duchenne muscular dystrophy (DMD. Patient-derived iPSCs are an especially ideal cell source to obtain an unlimited number of myogenic cells that escape immune rejection after engraftment. Currently, there are several approaches to induce differentiation of ESCs and iPSCs to skeletal muscle. A key to the generation of skeletal muscle cells from ESCs/iPSCs is the mimicking of embryonic mesodermal induction followed by myogenic induction. Thus, current approaches of skeletal muscle cell induction of ESCs/iPSCs utilize techniques including overexpression of myogenic transcription factors such as MyoD or Pax3, using small molecules to induce mesodermal cells followed by myogenic progenitor cells, and utilizing epigenetic myogenic memory existing in muscle cell-derived iPSCs. This review summarizes the current methods used in myogenic differentiation and highlights areas of recent improvement.

Exercise Promotes Healthy Aging of Skeletal Muscle.

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Cartee, Gregory D; Hepple, Russell T; Bamman, Marcas M; Zierath, Juleen R

2016-06-14

Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes "healthy aging" by inducing modifications in skeletal muscle. Copyright © 2016 Elsevier Inc. All rights reserved.

Skeletal muscle metabolism in hypokinetic rats

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Tischler, Marc E.

1993-01-01

This grant focused on the mechanisms of metabolic changes associated with unweighting atrophy and reduced growth of hind limb muscles of juvenile rats. Metabolic studies included a number of different areas. Amino acid metabolic studies placed particular emphasis on glutamine and branched-chain amino acid metabolism. These studies were an outgrowth of understanding stress effects and the role of glucocorticoids in these animals. Investigations on protein metabolism were largely concerned with selective loss of myofibrillar proteins and the role of muscle proteolysis. These investigations lead to finding important differences from denervation and atrophy and to define the roles of cytosolic versus lysosomal proteolysis in these atrophy models. A major outgrowth of these studies was demonstrating an ability to prevent atrophy of the unweighted muscle for at least 24 hours. A large amount of work concentrated on carbohydrate metabolism and its regulation by insulin and catecholamines. Measurements focused on glucose transport, glycogen metabolism, and glucose oxidation. The grant was used to develop an important new in situ approach for studying protein metabolism, glucose transport, and hormonal effects which involves intramuscular injection of various agents for up to 24 hours. Another important consequence of this project was the development and flight of Physiological-Anatomical Rodent Experiment-1 (PARE-1), which was launched aboard Space Shuttle Discovery in September 1991. Detailed descriptions of these studies can be found in the 30 peer-reviewed publications, 15 non-reviewed publications, 4 reviews and 33 abstracts (total 82 publications) which were or are scheduled to be published as a result of this project. A listing of these publications grouped by area (i.e. amino acid metabolism, protein metabolism, carbohydrate metabolism, and space flight studies) are included.

Measurement and Treatment of Passive Muscle Stiffness

DEFF Research Database (Denmark)

Kirk, Henrik

, which aimed to investigate: 1) The development of a clinical method to evaluate and distinguish neural (reflex mediated stiffness) and non-neural (passive muscle stiffness) components of muscle stiffness in adults with CP by objective and reliable measurements. 2) The association between increased...... and reliability of the method, and argue for the use of the method in the clinical practice. The device is able to distinguish between passive muscle stiffness and reflex-mediated stiffness in subjects with CP. It shows good high intrarater and interrater reliability in evaluation of passive muscle stiffness...... to measure muscle stiffness, and distinguish between passive muscle stiffness and reflex-mediated stiffness. Furthermore, it is a reliable device to measure changes in passive ROM. Treatment of passive muscle stiffness should be directed towards intense training, comprising many repetitions with a functional...

Dynamic epigenetic responses to muscle contraction

DEFF Research Database (Denmark)

Rasmussen, Morten; Zierath, Juleen R; Barrès, Romain

2014-01-01

Skeletal muscle is a malleable organ that responds to a single acute exercise bout by inducing the expression of genes involved in structural, metabolic and functional adaptations. Several epigenetic mechanisms including histone H4 deacetylation and loss of promoter methylation have been implicated...... in modifying exercise-responsive gene expression. These transient changes suggest that epigenetic mechanisms are not restricted to early stages of human development but are broad dynamic controllers of genomic plasticity in response to environmental factors....

Zebrafish embryos exposed to alcohol undergo abnormal development of motor neurons and muscle fibers.

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Sylvain, Nicole J; Brewster, Daniel L; Ali, Declan W

2010-01-01

Children exposed to alcohol in utero have significantly delayed gross and fine motor skills, as well as deficiencies in reflex development. The reasons that underlie the motor deficits caused by ethanol (EtOH) exposure remain to be fully elucidated. The present study was undertaken to investigate the effects of embryonic alcohol exposure (1.5%, 2% and 2.5% EtOH) on motor neuron and muscle fiber morphology in 3 days post fertilization (dpf) larval zebrafish. EtOH treated fish exhibited morphological deformities and fewer bouts of swimming in response to touch, compared with untreated fish. Immunolabelling with anti-acetylated tubulin indicated that fish exposed to 2.5% EtOH had significantly higher rates of motor neuron axon defects. Immunolabelling of primary and secondary motor neurons, using znp-1 and zn-8, revealed that fish exposed to 2% and 2.5% EtOH exhibited significantly higher rates of primary and secondary motor neuron axon defects compared to controls. Examination of red and white muscle fibers revealed that fish exposed to EtOH had significantly smaller fibers compared with controls. These findings indicate that motor neuron and muscle fiber morphology is affected by early alcohol exposure in zebrafish embryos, and that this may be related to deficits in locomotion. Copyright 2010 Elsevier Inc. All rights reserved.

A mouse anti-myostatin antibody increases muscle mass and improves muscle strength and contractility in the mdx mouse model of Duchenne muscular dystrophy and its humanized equivalent, domagrozumab (PF-06252616), increases muscle volume in cynomolgus monkeys.

Science.gov (United States)

St Andre, Michael; Johnson, Mark; Bansal, Prashant N; Wellen, Jeremy; Robertson, Andrew; Opsahl, Alan; Burch, Peter M; Bialek, Peter; Morris, Carl; Owens, Jane

2017-11-09

The treatments currently approved for Duchenne muscular dystrophy (DMD), a progressive skeletal muscle wasting disease, address the needs of only a small proportion of patients resulting in an urgent need for therapies that benefit all patients regardless of the underlying mutation. Myostatin is a member of the transforming growth factor-β (TGF-β) family of ligands and is a negative regulator of skeletal muscle mass. Loss of myostatin has been shown to increase muscle mass and improve muscle function in both normal and dystrophic mice. Therefore, myostatin blockade via a specific antibody could ameliorate the muscle weakness in DMD patients by increasing skeletal muscle mass and function, thereby reducing patients' functional decline. A murine anti-myostatin antibody, mRK35, and its humanized analog, domagrozumab, were developed and their ability to inhibit several TGB-β ligands was measured using a cell-based Smad-activity reporter system. Normal and mdx mice were treated with mRK35 to examine the antibody's effect on body weight, lean mass, muscle weights, grip strength, ex vivo force production, and fiber size. The humanized analog (domagrozumab) was tested in non-human primates (NHPs) for changes in skeletal muscle mass and volume as well as target engagement via modulation of circulating myostatin. Both the murine and human antibodies are specific and potent inhibitors of myostatin and GDF11. mRK35 is able to increase body weight, lean mass, and muscle weights in normal mice. In mdx mice, mRK35 significantly increased body weight, muscle weights, grip strength, and ex vivo force production in the extensor digitorum longus (EDL) muscle. Further, tibialis anterior (TA) fiber size was significantly increased. NHPs treated with domagrozumab demonstrated a dose-dependent increase in lean mass and muscle volume and exhibited increased circulating levels of myostatin demonstrating target engagement. We demonstrated that the potent anti-myostatin antibody mRK35 and

Artificial Muscle Kits for the Classroom

Science.gov (United States)

2004-01-01

Commonly referred to as "artificial muscles," electroactive polymer (EAP) materials are lightweight strips of highly flexible plastic that bend or stretch when subjected to electric voltage. EAP materials may prove to be a substitution for conventional actuation components such as motors and gears. Since the materials behave similarly to biological muscles, this emerging technology has the potential to develop improved prosthetics and biologically-inspired robots, and may even one day replace damaged human muscles. The practical application of artificial muscles provides a challenge, however, since the material requires improved effectiveness and durability before it can fulfill its potential.

AMPK in skeletal muscle function and metabolism

DEFF Research Database (Denmark)

Kjøbsted, Rasmus; Hingst, Janne Rasmuss; Fentz, Joachim

2018-01-01

Skeletal muscle possesses a remarkable ability to adapt to various physiologic conditions. AMPK is a sensor of intracellular energy status that maintains energy stores by fine-tuning anabolic and catabolic pathways. AMPK's role as an energy sensor is particularly critical in tissues displaying...... highly changeable energy turnover. Due to the drastic changes in energy demand that occur between the resting and exercising state, skeletal muscle is one such tissue. Here, we review the complex regulation of AMPK in skeletal muscle and its consequences on metabolism (e.g., substrate uptake, oxidation......, and storage as well as mitochondrial function of skeletal muscle fibers). We focus on the role of AMPK in skeletal muscle during exercise and in exercise recovery. We also address adaptations to exercise training, including skeletal muscle plasticity, highlighting novel concepts and future perspectives...

Disease-Induced Skeletal Muscle Atrophy and Fatigue

NARCIS (Netherlands)

Powers, Scott K.; Lynch, Gordon S.; Murphy, Kate T.; Reid, Michael B.; Zijdewind, Inge

2016-01-01

Numerous health problems including acute critical illness, cancer, diseases associated with chronic inflammation, and neurological disorders often result in skeletal muscle weakness and fatigue. Disease-related muscle atrophy and fatigue is an important clinical problem because acquired skeletal

Redox Control of Skeletal Muscle Regeneration.

Science.gov (United States)

Le Moal, Emmeran; Pialoux, Vincent; Juban, Gaëtan; Groussard, Carole; Zouhal, Hassane; Chazaud, Bénédicte; Mounier, Rémi

2017-08-10

Skeletal muscle shows high plasticity in response to external demand. Moreover, adult skeletal muscle is capable of complete regeneration after injury, due to the properties of muscle stem cells (MuSCs), the satellite cells, which follow a tightly regulated myogenic program to generate both new myofibers and new MuSCs for further needs. Although reactive oxygen species (ROS) and reactive nitrogen species (RNS) have long been associated with skeletal muscle physiology, their implication in the cell and molecular processes at work during muscle regeneration is more recent. This review focuses on redox regulation during skeletal muscle regeneration. An overview of the basics of ROS/RNS and antioxidant chemistry and biology occurring in skeletal muscle is first provided. Then, the comprehensive knowledge on redox regulation of MuSCs and their surrounding cell partners (macrophages, endothelial cells) during skeletal muscle regeneration is presented in normal muscle and in specific physiological (exercise-induced muscle damage, aging) and pathological (muscular dystrophies) contexts. Recent advances in the comprehension of these processes has led to the development of therapeutic assays using antioxidant supplementation, which result in inconsistent efficiency, underlying the need for new tools that are aimed at precisely deciphering and targeting ROS networks. This review should provide an overall insight of the redox regulation of skeletal muscle regeneration while highlighting the limits of the use of nonspecific antioxidants to improve muscle function. Antioxid. Redox Signal. 27, 276-310.

Determining the role of skewed X-chromosome inactivation in developing muscle symptoms in carriers of Duchenne muscular dystrophy.

Science.gov (United States)

Viggiano, Emanuela; Ergoli, Manuela; Picillo, Esther; Politano, Luisa

2016-07-01

Duchenne and Becker dystrophinopathies (DMD and BMD) are X-linked recessive disorders caused by mutations in the dystrophin gene that lead to absent or reduced expression of dystrophin in both skeletal and heart muscles. DMD/BMD female carriers are usually asymptomatic, although about 8 % may exhibit muscle or cardiac symptoms. Several mechanisms leading to a reduced dystrophin have been hypothesized to explain the clinical manifestations and, in particular, the role of the skewed XCI is questioned. In this review, the mechanism of XCI and its involvement in the phenotype of BMD/DMD carriers with both a normal karyotype or with X;autosome translocations with breakpoints at Xp21 (locus of the DMD gene) will be analyzed. We have previously observed that DMD carriers with moderate/severe muscle involvement, exhibit a moderate or extremely skewed XCI, in particular if presenting with an early onset of symptoms, while DMD carriers with mild muscle involvement present a random XCI. Moreover, we found that among 87.1 % of the carriers with X;autosome translocations involving the locus Xp21 who developed signs and symptoms of dystrophinopathy such as proximal muscle weakness, difficulty to run, jump and climb stairs, 95.2 % had a skewed XCI pattern in lymphocytes. These data support the hypothesis that skewed XCI is involved in the onset of phenotype in DMD carriers, the X chromosome carrying the normal DMD gene being preferentially inactivated and leading to a moderate-severe muscle involvement.

Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

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Lynn Bar-On

Full Text Available The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01. The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between

Neuropathic pain-like alterations in muscle nociceptor function associated with vibration-induced muscle pain.

Science.gov (United States)

Chen, Xiaojie; Green, Paul G; Levine, Jon D

2010-11-01

We recently developed a rodent model of the painful muscle disorders induced by occupational exposure to vibration. In the present study we used this model to evaluate the function of sensory neurons innervating the vibration-exposed gastrocnemius muscle. Activity of 74 vibration-exposed and 40 control nociceptors, with mechanical receptive fields in the gastrocnemius muscle, were recorded. In vibration-exposed rats ∼15% of nociceptors demonstrated an intense and long-lasting barrage of action potentials in response to sustained suprathreshold mechanical stimulation (average of 2635 action potentials with frequency of ∼44Hz during a 1min suprathreshold stimulus) much greater than that has been reported to be produced even by potent inflammatory mediators. While these high-firing nociceptors had lower mechanical thresholds than the remaining nociceptors, exposure to vibration had no effect on conduction velocity and did not induce spontaneous activity. Hyperactivity was not observed in any of 19 neurons from vibration-exposed rats pretreated with intrathecal antisense for the IL-6 receptor subunit gp130. Since vibration can injure peripheral nerves and IL-6 has been implicated in painful peripheral neuropathies, we suggest that the dramatic change in sensory neuron function and development of muscles pain, induced by exposure to vibration, reflects a neuropathic muscle pain syndrome. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

Science.gov (United States)

Tomlinson, D J; Erskine, R M; Morse, C I; Winwood, K; Onambélé-Pearson, Gladys

2016-06-01

Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated.

Changes in maximum muscle strength and rapid muscle force characteristics after long-term special support and reconnaissance missions

DEFF Research Database (Denmark)

Christensen, Peter Astrup; Jacobsen, Jacob Ole; Thorlund, Jonas B

2008-01-01

PURPOSE: The purpose of the present study was to examine the impact of 8 days of immobilization during a Special Support and Reconnaissance mission (SSR) on muscle mass, contraction dynamics, maximum jump height/power, and body composition. METHODS: Unilateral maximal voluntary contraction, rate...... of force development, and maximal jump height were tested to assess muscle strength/power along with whole-body impedance analysis before and after SSR. RESULTS: Body weight, fat-free mass, and total body water decreased (4-5%) after SSR, along with impairments in maximal jump height (-8%) and knee...... extensor maximal voluntary contraction (-10%). Furthermore, rate of force development was severely affected (-15-30%). CONCLUSIONS: Eight days of immobilization during a covert SSR mission by Special Forces soldiers led to substantial decrements in maximal muscle force and especially in rapid muscle force...

Increased Stiffness in Aged Skeletal Muscle Impairs Muscle Progenitor Cell Proliferative Activity.

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Grégory Lacraz

Full Text Available Skeletal muscle aging is associated with a decreased regenerative potential due to the loss of function of endogenous stem cells or myogenic progenitor cells (MPCs. Aged skeletal muscle is characterized by the deposition of extracellular matrix (ECM, which in turn influences the biomechanical properties of myofibers by increasing their stiffness. Since the stiffness of the MPC microenvironment directly impacts MPC function, we hypothesized that the increase in muscle stiffness that occurs with aging impairs the behavior of MPCs, ultimately leading to a decrease in regenerative potential.We showed that freshly isolated individual myofibers from aged mouse muscles contain fewer MPCs overall than myofibers from adult muscles, with fewer quiescent MPCs and more proliferative and differentiating MPCs. We observed alterations in cultured MPC behavior in aged animals, where the proliferation and differentiation of MPCs were lower and higher, respectively. These alterations were not linked to the intrinsic properties of aged myofibers, as shown by the similar values for the cumulative population-doubling values and fusion indexes. However, atomic force microscopy (AFM indentation experiments revealed a nearly 4-fold increase in the stiffness of the MPC microenvironment. We further showed that the increase in stiffness is associated with alterations to muscle ECM, including the accumulation of collagen, which was correlated with higher hydroxyproline and advanced glycation end-product content. Lastly, we recapitulated the impaired MPC behavior observed in aging using a hydrogel substrate that mimics the stiffness of myofibers.These findings provide novel evidence that the low regenerative potential of aged skeletal muscle is independent of intrinsic MPC properties but is related to the increase in the stiffness of the MPC microenvironment.

Live imaging of muscle histolysis in Drosophila metamorphosis.

Science.gov (United States)

Kuleesha, Yadav; Puah, Wee Choo; Wasser, Martin

2016-05-04

The contribution of programmed cell death (PCD) to muscle wasting disorders remains a matter of debate. Drosophila melanogaster metamorphosis offers the opportunity to study muscle cell death in the context of development. Using live cell imaging of the abdomen, two groups of larval muscles can be observed, doomed muscles that undergo histolysis and persistent muscles that are remodelled and survive into adulthood. To identify and characterize genes that control the decision between survival and cell death of muscles, we developed a method comprising in vivo imaging, targeted gene perturbation and time-lapse image analysis. Our approach enabled us to study the cytological and temporal aspects of abnormal cell death phenotypes. In a previous genetic screen for genes controlling muscle size and cell death in metamorphosis, we identified gene perturbations that induced cell death of persistent or inhibit histolysis of doomed larval muscles. RNA interference (RNAi) of the genes encoding the helicase Rm62 and the lysosomal Cathepsin-L homolog Cysteine proteinase 1 (Cp1) caused premature cell death of persistent muscle in early and mid-pupation, respectively. Silencing of the transcriptional co-repressor Atrophin inhibited histolysis of doomed muscles. Overexpression of dominant-negative Target of Rapamycin (TOR) delayed the histolysis of a subset of doomed and induced ablation of all persistent muscles. RNAi of AMPKα, which encodes a subunit of the AMPK protein complex that senses AMP and promotes ATP formation, led to loss of attachment and a spherical morphology. None of the perturbations affected the survival of newly formed adult muscles, suggesting that the method is useful to find genes that are crucial for the survival of metabolically challenged muscles, like those undergoing atrophy. The ablation of persistent muscles did not affect eclosion of adult flies. Live imaging is a versatile approach to uncover gene functions that are required for the survival of

HDAC4-Myogenin Axis As an Important Marker of HD-Related Skeletal Muscle Atrophy

Science.gov (United States)

Smeets, Cleo J. L. M.; Franklin, Sophie A.; Bondulich, Marie K.; Jolinon, Nelly; Muller, Thomas; Ahmed, Mhoriam; Dick, James R. T.; Piotrowska, Izabela; Greensmith, Linda; Smolenski, Ryszard T.; Bates, Gillian P.

2015-01-01

Skeletal muscle remodelling and contractile dysfunction occur through both acute and chronic disease processes. These include the accumulation of insoluble aggregates of misfolded amyloid proteins that is a pathological feature of Huntington’s disease (HD). While HD has been described primarily as a neurological disease, HD patients’ exhibit pronounced skeletal muscle atrophy. Given that huntingtin is a ubiquitously expressed protein, skeletal muscle fibres may be at risk of a cell autonomous HD-related dysfunction. However the mechanism leading to skeletal muscle abnormalities in the clinical and pre-clinical HD settings remains unknown. To unravel this mechanism, we employed the R6/2 transgenic and HdhQ150 knock-in mouse models of HD. We found that symptomatic animals developed a progressive impairment of the contractile characteristics of the hind limb muscles tibialis anterior (TA) and extensor digitorum longus (EDL), accompanied by a significant loss of motor units in the EDL. In symptomatic animals, these pronounced functional changes were accompanied by an aberrant deregulation of contractile protein transcripts and their up-stream transcriptional regulators. In addition, HD mouse models develop a significant reduction in muscle force, possibly as a result of a deterioration in energy metabolism and decreased oxidation that is accompanied by the re-expression of the HDAC4-DACH2-myogenin axis. These results show that muscle dysfunction is a key pathological feature of HD. PMID:25748626

Reliability of Ultrasonographic Measurement of Cervical Multifidus Muscle Dimensions during Isometric Contraction of Neck Muscles

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Somayeh Amiri Arimi

2012-07-01

Full Text Available Background and Aim: Cervical multifidus is considered as one of the most important neck stabilizers. Weakness and muscular atrophy of this muscle were seen in patients with chronic neck pain. Ultrasonographic imaging is a non-invasive and feasible technique that commonly used to record such changes and measure muscle dimensions. Therefore, the aim of this study was to evaluate the reliability of ultrasonographic measurement of cervical multifidus muscle’s dimensions during isometric contraction of neck muscles. Materials and Method: Ten subjects (5 patients with chronic neck pain and 5 healthy subjects were recruited in this study. Cervical multifidus muscle’s dimensions were measured at the level of forth cervical vertebrae. Ultrasonographic measurement of cervical multifidus muscle at rest, 50% and 100% of maximal voluntary contraction (MVC were performed by one examiner within 1 week interval. The dimensions of cervical multifidus muscle including cross-sectional area (CSA, anterior posterior dimension (APD, and lateral dimension (LD were measured. Intraclass correlation coefficients (ICC, standard error of measurement (SEM and minimal detectable change (MDC were computed for data analysis.Results: The between days reliability of maximum strength of neck muscles and multifidus muscle dimensions at rest, 50% and 100% of MVC of neck muscles were good to excellent (ICC=0.75-0.99.Conclusion: The results of this study showed that ultrasonographic measuring of cervical multifidus muscle’s dimensions during isometric contraction of neck muscles at the level of C4 in females with chronic neck pain and healthy subjects is a reliable and repeatable method.

Roles of TGF-β/Smad signaling pathway in pathogenesis and development of gluteal muscle contracture.

Science.gov (United States)

Zhang, Xintao; Ma, Yukun; You, Tian; Tian, Xiaopeng; Zhang, Honglei; Zhu, Qi; Zhang, Wentao

2015-02-01

Gluteal muscle contracture (GMC) is a chronic fibrotic disease of gluteal muscles which is characterized by excessive deposition of collagen in the extracellular matrix. Transforming growth factor (TGF)-βs have been shown to play an important role in the progression of GMC. However, the underlying mechanisms are not entirely clear. We sought to explore the expression of TGF-β/Smad pathway proteins and their downstream targets in gluteal muscle contracture disease. The expression levels of collagens type I/III, TGF-β1, Smad2/3/4/7 and PAI-1 (plasminogen activator inhibitor type 1) in gluteal muscle contraction (GMC) patients were measured using immunohistochemistry, reverse transcription and polymerase chain reaction (RT-PCR) and western blot assays. The expressions of collagens type I/III and TGF-β1 were significantly increased in the contraction band compared with unaffected muscle. In addition, R-Smad phosphorylation and Smad4 protein expression in the contraction band were also elevated, while the expression of Smad7 was significantly decreased in the fibrotic muscle of the GMC patients compared to the unaffected adjacent muscle. The protein and mRNA levels of PAI-1 were also remarkably increased in the contraction band compared with adjacent muscle. Immunohistochemical analysis also demonstrated that the expression levels of TGF-β1 and PAI-1 were higher in contraction band than those in the adjacent muscle. Our data confirm the stimulating effects of the TGF-β/Smad pathway in gluteal muscle contracture disease and reveal the internal changes of TGF-β/Smad pathway proteins and their corresponding targets in gluteal muscle contracture patients.

Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages

International Nuclear Information System (INIS)

Arsic, Nikola; Mamaeva, Daria; Lamb, Ned J.; Fernandez, Anne

2008-01-01

Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal β III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders

Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages.

Science.gov (United States)

Arsic, Nikola; Mamaeva, Daria; Lamb, Ned J; Fernandez, Anne

2008-04-01

Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal beta III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders.

Improvement of maternal vitamin D status with 25-hydroxycholecalciferol positively impacts porcine fetal skeletal muscle development and myoblast activity.

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Hines, E A; Coffey, J D; Starkey, C W; Chung, T K; Starkey, J D

2013-09-01

There is little information available regarding the influence of maternal vitamin D status on fetal skeletal muscle development. Therefore, we investigated the effect of improved vitamin D status resulting from 25-hydroxycholecalciferol (25OHD3) supplementation of dams on fetal skeletal muscle developmental characteristics and myoblast activity using Camborough 22 gilts (n = 40) randomly assigned to 1 of 2 corn-soybean meal-based diets. The control diet (CTL) contained 2,500 IU cholecalciferol (D3)/kg diet, whereas the experimental diet contained 500 IU D3/kg diet plus 50 µg 25OHD3/kg diet. Gilts were fed 2.7 kg of their assigned diet once daily beginning 43 d before breeding through d 90 of gestation. On gestational d 90 (± 1), fetal LM and semitendinosus muscle samples were collected for analysis of developmental characteristics and myoblast activity, respectively. No treatment difference was observed in fetal LM cross-sectional area (P = 0.25). Fetuses from 25OHD3-supplemented gilts had more LM fibers (P = 0.04) that tended to be smaller in cross-sectional area compared with CTL fetuses (P = 0.11). A numerical increase in the total number of Pax7+ myoblasts was also observed in fetuses from 25OHD3-supplemented gilts (P = 0.12). Myoblasts derived from the muscles of fetuses from 25OHD3-fed dams displayed an extended proliferative phase in culture compared with those from fetuses of dams fed only D3 (P importance of maternal vitamin D status on the development of fetal skeletal muscle.

Histomorphometrical aspects of the postnatal development of masticatory muscle in the muscular dystrophic mouse

DEFF Research Database (Denmark)

Vilmann, H; Kirkeby, S

1991-01-01

amount of connective tissue between the fibres. The histomorphometrical observations revealed an increase in mean size of the fibres with age, both in normal and dystrophic masticatory muscles. The fibre size variance which has been shown to be a reliable parameter for description of degree of affection...... criteria to separate dystrophic muscles from normal muscles at birth. From 2 weeks onwards marked differences between the affected and unaffected muscles appeared, as the affected fibres from this age are rounded with marked variations in size. Central nucleation is frequent and there is an increased...

CORRELATIONS BETWEEN MUSCLE MASS, MUSCLE STRENGTH, PHYSICAL PERFORMANCE, AND MUSCLE FATIGUE RESISTANCE IN COMMUNITY-DWELLING ELDERLY SUBJECTS

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Elizabeth

2016-03-01

Full Text Available Objective: To determine the correlations between muscle mass, muscle strength, physical performance, and muscle fatigue resistance in community-dwelling elderly people in order to elucidate factors which contribute to elderly’s performance of daily activities. Methods: A cross-sectional study was conducted on community-dwelling elderly in Bandung from September to December 2014. One hundred and thirty elderly, 60 years old or above, were evaluated using bioelectrical impedance analysis to measure muscle mass; grip strength to measure muscle strength and muscle fatigue resistance; habitual gait speed to measure physical performance; and Global Physical Activity Questionnaire (GPAQ to assess physical activity. Results: There were significant positive correlations between muscle mass (r=0,27, p=0,0019, muscle strength (r=0,26, p=0,0024, and physical performance (r=0,32, p=0,0002 with muscle fatigue resistance. Physical performance has the highest correlation based on multiple regression test (p=0,0025. In association with muscle mass, the physical activity showed a significant positive correlation (r=0,42, p=0,0000. Sarcopenia was identified in 19 (14.61% of 130 subjects. Conclusions: It is suggested that muscle mass, muscle strength, and physical performance influence muscle fatigue resistance.

[Muscle biopsy in children: Usefulness in 2012].

Science.gov (United States)

Cuisset, J-M; Maurage, C-A; Carpentier, A; Briand, G; Thévenon, A; Rouaix, N; Vallée, L

2013-01-01

Muscle biopsy is a mainstay diagnostic tool for investigating neuromuscular disorders in children. We report the yield of pediatric muscle biopsy in a population of 415 children by a retrospective study of 419 biopsies performed between 1/01/2000 and 31/12/2009 in a neuropediatric department, including mitochondrial respiratory chain analysis for 87 children. Two hundred and fifty-five biopsies were from boys (61%) 164 from girls (39%). Their mean age at biopsy was 6.5years; 155 (37%) biopsies were obtained before the child was 5years old. Final histopathological diagnoses were: congenital myopathy (n=193, including 15 structural congenital myopathies); progressive muscular dystrophy (n=75 [18%] including 57 dystrophinopathies); congenital muscular dystrophy (n=17, including six primary merosinopathies); dermatomyositis (n=11); spinal muscular atrophy (n=9, including six atypical spinal muscular atrophies); metabolic myopathy (n=32, including 19 mitochondrial myopathies); encephalomyopathy (n=53 [13%], including 27 with a mitochondrial respiratory chain defect). Pathological diagnosis remained undetermined in 16 cases. In 184 patients (44%), the muscle biopsy revealed specific histopathological anomalies (dystrophic process; specific ultrastructural abnormalities; perifascicular atrophy; neurogenic atrophy; metabolic anomalies) enabling a precise etiological diagnosis. For 85% of progressive muscular dystrophies, the biopsy resulted in a genetic diagnosis after identification of the protein defect. In 15% of the congenital myopathies, histopathological anomalies focused attention on one or several genes. Concerning dystrophinopathies, quantification of dystrophin deficiency on the biopsy specimen contributed to the definition of the clinical phenotype: Duchenne, or Becker. In children with a myopathy, muscle biopsy is often indispensable to establish the etiological diagnosis. Based on the results from this series, muscle biopsy can provide a precise

Development of active, nanoparticle, antimicrobial technologies for muscle-based packaging applications

OpenAIRE

Morris, Michael A.; Padmanabhan, Sibu C.; Cruz-Romero, Malco C.; Cummins, Enda; Kerry, Joseph P.

2017-01-01

Fresh and processed muscle-based foods are highly perishable food products and packaging plays a crucial role in providing containment so that the full effect of preservation can be achieved through the provision of shelf-life extension. Conventional packaging materials and systems have served the industry well, however, greater demands are being placed upon industrial packaging formats owing to the movement of muscle-based products to increasingly distant markets, as well as increased custom...

Bigorexia: bodybuilding and muscle dysmorphia.

Science.gov (United States)

Mosley, Philip E

2009-05-01

Muscle dysmorphia is an emerging condition that primarily affects male bodybuilders. Such individuals obsess about being inadequately muscular. Compulsions include spending hours in the gym, squandering excessive amounts of money on ineffectual sports supplements, abnormal eating patterns or even substance abuse. In this essay, I illustrate the features of muscle dysmorphia by employing the first-person account of a male bodybuilder afflicted by this condition. I briefly outline the history of bodybuilding and examine whether the growth of this sport is linked to a growing concern with body image amongst males. I suggest that muscle dysmorphia may be a new expression of a common pathology shared with the eating disorders.

Congenital muscle dystrophy and diet consistency affect mouse skull shape differently.

Science.gov (United States)

Spassov, Alexander; Toro-Ibacache, Viviana; Krautwald, Mirjam; Brinkmeier, Heinrich; Kupczik, Kornelius

2017-11-01

The bones of the mammalian skull respond plastically to changes in masticatory function. However, the extent to which muscle function affects the growth and development of the skull, whose regions have different maturity patterns, remains unclear. Using muscle dissection and 3D landmark-based geometric morphometrics we investigated the effect of changes in muscle function established either before or after weaning, on skull shape and muscle mass in adult mice. We compared temporalis and masseter mass and skull shape in mice with a congenital muscle dystrophy (mdx) and wild type (wt) mice fed on either a hard or a soft diet. We found that dystrophy and diet have distinct effects on the morphology of the skull and the masticatory muscles. Mdx mice show a flattened neurocranium with a more dorsally displaced foramen magnum and an anteriorly placed mandibular condyle compared with wt mice. Compared with hard diet mice, soft diet mice had lower masseter mass and a face with more gracile features as well as labially inclined incisors, suggesting reduced bite strength. Thus, while the early-maturing neurocranium and the posterior portion of the mandible are affected by the congenital dystrophy, the late-maturing face including the anterior part of the mandible responds to dietary differences irrespective of the mdx mutation. Our study confirms a hierarchical, tripartite organisation of the skull (comprising neurocranium, face and mandible) with a modular division based on development and function. Moreover, we provide further experimental evidence that masticatory loading is one of the main environmental stimuli that generate craniofacial variation. © 2017 Anatomical Society.

Genome-wide mapping of Sox6 binding sites in skeletal muscle reveals both direct and indirect regulation of muscle terminal differentiation by Sox6

Directory of Open Access Journals (Sweden)

An Chung-Il

2011-10-01

Full Text Available Abstract Background Sox6 is a multi-faceted transcription factor involved in the terminal differentiation of many different cell types in vertebrates. It has been suggested that in mice as well as in zebrafish Sox6 plays a role in the terminal differentiation of skeletal muscle by suppressing transcription of slow fiber specific genes. In order to understand how Sox6 coordinately regulates the transcription of multiple fiber type specific genes during muscle development, we have performed ChIP-seq analyses to identify Sox6 target genes in mouse fetal myotubes and generated muscle-specific Sox6 knockout (KO mice to determine the Sox6 null muscle phenotype in adult mice. Results We have identified 1,066 Sox6 binding sites using mouse fetal myotubes. The Sox6 binding sites were found to be associated with slow fiber-specific, cardiac, and embryonic isoform genes that are expressed in the sarcomere as well as transcription factor genes known to play roles in muscle development. The concurrently performed RNA polymerase II (Pol II ChIP-seq analysis revealed that 84% of the Sox6 peak-associated genes exhibited little to no binding of Pol II, suggesting that the majority of the Sox6 target genes are transcriptionally inactive. These results indicate that Sox6 directly regulates terminal differentiation of muscle by affecting the expression of sarcomere protein genes as well as indirectly through influencing the expression of transcription factors relevant to muscle development. Gene expression profiling of Sox6 KO skeletal and cardiac muscle revealed a significant increase in the expression of the genes associated with Sox6 binding. In the absence of the Sox6 gene, there was dramatic upregulation of slow fiber-specific, cardiac, and embryonic isoform gene expression in Sox6 KO skeletal muscle and fetal isoform gene expression in Sox6 KO cardiac muscle, thus confirming the role Sox6 plays as a transcriptional suppressor in muscle development

Strength and fatigability of selected muscles in upper limb: assessing muscle imbalance relevant to tennis elbow.

Science.gov (United States)

Alizadehkhaiyat, O; Fisher, A C; Kemp, G J; Frostick, S P

2007-08-01

The aetiology of tennis elbow has remained uncertain for more than a century. To examine muscle imbalance as a possible pathophysiological factor requires a reliable method of assessment. This paper describes the development of such a method and its performance in healthy subjects. We propose a combination of surface and fine-wire EMG of shoulder and forearm muscles and wrist strength measurements as a reliable tool for assessing muscle imbalance relevant to the pathophysiology of tennis elbow. Six healthy volunteers participated. EMG data were acquired at 50% maximal voluntary isometric contraction from five forearm muscles during grip and three shoulder muscles during external rotation and abduction, and analysed using normalized median frequency slope as a fatigue index. Wrist extension/flexion strength was measured using a purpose-built dynamometer. Significant negative slope of median frequency was found for all muscles, with good reproducibility, and no significant difference in slope between the different muscles of the shoulder and the wrist. (Amplitude slope showed high variability and was therefore unsuitable for this purpose.) Wrist flexion was 27+/-8% stronger than extension (mean+/-SEM, p=0.006). This is a reliable method for measuring muscle fatigue in forearm and shoulder. EMG and wrist strength studies together can be used for assessing and identifying the muscle balance in the wrist-forearm-shoulder chain.

TRAINING-INDUCED CHANGES IN THE TOPOGRAPHY OF MUSCLE TORQUES AND MAXIMAL MUSCLE TORQUES IN BASKETBALL PLAYERS

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Krzysztof Buśko

2012-01-01

Full Text Available The aim of the study was to detect changes in the maximal muscle torques in male basketball players during a two-year training cycle. We verified the hypothesis that different workloads applied during the preparation and competition periods would result in changes in the maximal muscle torques of the athletes (increase during the former and decrease or no change during the latter period accompanied by no alteration of the percent muscle topography of all the muscle groups tested. The examinations were conducted on nine senior male basketball players from the Polish national team. Estimations of the muscle torques in static conditions were performed at the end of the preparation (measurements I and III and competition (measurements II and IV periods of a two-year training cycle. Eleven muscle groups were studied including flexors and extensors of the trunk and flexors and extensors of the shoulder, the elbow, the hip, the knee, and the ankle. Muscle torques of the shoulder and the elbow insignificantly decreased except for the muscle torque of the flexors of the shoulder. Muscle torques of the flexors and extensors of the trunk as well as of the flexors and extensors of the hip, the knee, and the ankle increased between measurements I and III and between measurements I and IV with the only exception being the muscle torque of the flexors of the knee (which significantly decreased by 7.4% In the case of the flexors and extensors of the trunk and the flexors and extensors of the hip, the changes appeared to be significant. The sum of the muscle torques of the upper limbs markedly decreased between the preparation (measurement I and competition (measurement IV periods. The sum of the muscle torques of the trunk and the lower limbs and the sum of the muscle torques of the eleven muscle groups significantly increased between measurements I and IV. Percent muscle topography significantly decreased for the flexors and extensors of the shoulder and the

Lack of the serum- and glucocorticoid-inducible kinase SGK1 improves muscle force characteristics and attenuates fibrosis in dystrophic mdx mouse muscle

DEFF Research Database (Denmark)

Steinberger, Martin; Föller, Michael; Vogelgesang, Silke

2015-01-01

Duchenne muscular dystrophy (DMD) is a human genetic disease characterized by fibrosis and severe muscle weakness. Currently, there is no effective treatment available to prevent progressive fibrosis in skeletal muscles. The serum- and glucocorticoid-inducible kinase SGK1 regulates a variety...... of physiological functions and participates in fibrosis stimulation. Here, we investigated whether SGK1 influences structure, function and/or fibrosis of the muscles from the mdx mouse, an animal model for DMD. As expected, mdx muscles showed the typical pathological features of muscular dystrophy including fiber...... size variations, central nuclei of muscle fibers, fibrosis in the diaphragm, and force reduction by 30–50 %. Muscles from sgk1 -/- mice were histologically overall intact and specific force was only slightly reduced compared to wild-type muscles. Surprisingly, soleus and diaphragm muscles of mdx/sgk1...

Retardation of muscle growth in castrated male mice: further ...

African Journals Online (AJOL)

Retardation of muscle growth in castrated male mice was studied as an evidence for the influence of hormones on the development of muscle mass. Male albino mice were castrated at 28days of age by open castration method. The weights and the muscle mass indices (mg muscle weight per gram body weight) of the ...

Painful unilateral temporalis muscle enlargement: reactive masticatory muscle hypertrophy.

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Katsetos, Christos D; Bianchi, Michael A; Jaffery, Fizza; Koutzaki, Sirma; Zarella, Mark; Slater, Robert

2014-06-01

An instance of isolated unilateral temporalis muscle hypertrophy (reactive masticatory muscle hypertrophy with fiber type 1 predominance) confirmed by muscle biopsy with histochemical fiber typing and image analysis in a 62 year-old man is reported. The patient presented with bruxism and a painful swelling of the temple. Absence of asymmetry or other abnormalities of the craniofacial skeleton was confirmed by magnetic resonance imaging and cephalometric analyses. The patient achieved symptomatic improvement only after undergoing botulinum toxin injections. Muscle biopsy is key in the diagnosis of reactive masticatory muscle hypertrophy and its distinction from masticatory muscle myopathy (hypertrophic branchial myopathy) and other non-reactive causes of painful asymmetric temporalis muscle enlargement.

Growth of limb muscle is dependent on skeletal-derived Indian hedgehog

OpenAIRE

Bren-Mattison, Yvette; Hausburg, Melissa; Olwin, Bradley B.

2011-01-01

During embryogenesis, muscle and bone develop in close temporal and spatial proximity. We show that Indian Hedgehog, a bone-derived signaling molecule, participates in growth of skeletal muscle. In Ihh−/− embryos, skeletal muscle development appears abnormal at embryonic day 14.5 and at later ages through embryonic day 20.5, dramatic losses of hindlimb muscle occur. To further examine the role of Ihh in myogenesis, we manipulated Ihh expression in the developing chick hindlimb. Reduction of I...

Supplementation with a Polyphenol-Rich Extract, TensLess® , Attenuates Delayed Onset Muscle Soreness and Improves Muscle Recovery from Damages After Eccentric Exercise.

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Romain, Cindy; Freitas, Tomás T; Martínez-Noguera, Francisco J; Laurent, Caroline; Gaillet, Sylvie; Chung, Linda H; Alcaraz, Pedro E; Cases, Julien

2017-11-01

High-intensity exercises are known to provoke delayed onset muscle soreness (DOMS). Delayed onset muscle soreness typically occurs within the first 24 h, peaks between 24 and 72 h, and can last as long as 5-7 days post-exercise. Delayed onset muscle soreness is a multifactorial process involving both mechanical and biochemical components, associated with clinical features that may limit range of motion, and athletes seek for effective recovery strategies to optimize future training sessions. TensLess ® is a food supplement developed to help manage post-exercise recovery. The supplement has been investigated on 13 recreationally active athletes of both sex, during a randomized, double-blind, and crossover clinical investigation, including a 3-week washout period. The clinical investigation was based on the study of TensLess ® effects for DOMS management and on the reduction of associated muscle damages following an eccentric exercise protocol. Supplementation with TensLess ® induced significant decrease in DOMS perception (-33%; p = 0.008) as of the first 24 h; this was significantly correlated with a lowered release of muscle damage-associated biomarkers, namely myoglobin, creatinine, and creatine kinase, for the whole length of the recovery period. Taken together, these positive results clearly indicate that post-exercise supplementation with TensLess ® may preserve myocytes and reduce soreness following eccentric exercise-induced damages, and, accordingly, significantly shorten muscle recovery. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Magnetic resonance imaging, ultrasound and real-time ultrasound elastography of the thigh muscles in congenital muscle dystrophy

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Drakonaki, Eleni E. [University of Crete, Radiology Department, Heraklion (Greece); Allen, Gina M. [Green Templeton College, Oxford (United Kingdom)

2010-04-15

Congenital muscle dystrophy includes a range of genetic disorders characterized by muscle weakness and contractures. We report the magnetic resonance (MR), ultrasound (US) and real-time sonoelastography (RTE) imaging findings of the thigh muscles of a 15-year-old boy with Bethlem myopathy diagnosed with clinical, electromyographic and histopathological criteria. Ultrasound and MR showed hyperechoic appearance and high signal intensity on T1- and T2-weighted sequences respectively at the periphery of the vastus lateralis and the long head of the biceps femoris muscles, and at a central area within the rectus femoris muscles. RTE was employed to examine the elastic properties of the muscle. The elastograms were presented as colour-coded maps superimposed on the B-mode images and revealed that the elastographic pattern correlated with the MR and US pattern of involvement. The abnormal muscle areas were stiffer (blue) than the normal-appearing areas (green), a finding that probably correlates with the presence of dystrophic collagen at the affected areas. This report suggests that RTE could be used as an additional imaging tool to evaluate the pattern of muscle changes in congenital myopathy. Further studies are needed to investigate the specificity and clinical value of RTE in the diagnosis and monitoring of neuromuscular disease. (orig.)

Magnetic resonance imaging, ultrasound and real-time ultrasound elastography of the thigh muscles in congenital muscle dystrophy

International Nuclear Information System (INIS)

Drakonaki, Eleni E.; Allen, Gina M.

2010-01-01

Congenital muscle dystrophy includes a range of genetic disorders characterized by muscle weakness and contractures. We report the magnetic resonance (MR), ultrasound (US) and real-time sonoelastography (RTE) imaging findings of the thigh muscles of a 15-year-old boy with Bethlem myopathy diagnosed with clinical, electromyographic and histopathological criteria. Ultrasound and MR showed hyperechoic appearance and high signal intensity on T1- and T2-weighted sequences respectively at the periphery of the vastus lateralis and the long head of the biceps femoris muscles, and at a central area within the rectus femoris muscles. RTE was employed to examine the elastic properties of the muscle. The elastograms were presented as colour-coded maps superimposed on the B-mode images and revealed that the elastographic pattern correlated with the MR and US pattern of involvement. The abnormal muscle areas were stiffer (blue) than the normal-appearing areas (green), a finding that probably correlates with the presence of dystrophic collagen at the affected areas. This report suggests that RTE could be used as an additional imaging tool to evaluate the pattern of muscle changes in congenital myopathy. Further studies are needed to investigate the specificity and clinical value of RTE in the diagnosis and monitoring of neuromuscular disease. (orig.)

cAMP signaling in skeletal muscle adaptation: hypertrophy, metabolism, and regeneration

Science.gov (United States)

Stewart, Randi

2012-01-01

Among organ systems, skeletal muscle is perhaps the most structurally specialized. The remarkable subcellular architecture of this tissue allows it to empower movement with instructions from motor neurons. Despite this high degree of specialization, skeletal muscle also has intrinsic signaling mechanisms that allow adaptation to long-term changes in demand and regeneration after acute damage. The second messenger adenosine 3′,5′-monophosphate (cAMP) not only elicits acute changes within myofibers during exercise but also contributes to myofiber size and metabolic phenotype in the long term. Strikingly, sustained activation of cAMP signaling leads to pronounced hypertrophic responses in skeletal myofibers through largely elusive molecular mechanisms. These pathways can promote hypertrophy and combat atrophy in animal models of disorders including muscular dystrophy, age-related atrophy, denervation injury, disuse atrophy, cancer cachexia, and sepsis. cAMP also participates in muscle development and regeneration mediated by muscle precursor cells; thus, downstream signaling pathways may potentially be harnessed to promote muscle regeneration in patients with acute damage or muscular dystrophy. In this review, we summarize studies implicating cAMP signaling in skeletal muscle adaptation. We also highlight ligands that induce cAMP signaling and downstream effectors that are promising pharmacological targets. PMID:22354781

Rat rotator cuff muscle responds differently from hindlimb muscle to a combined tendon-nerve injury.

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Davies, Michael R; Ravishankar, Bharat; Laron, Dominique; Kim, Hubert T; Liu, Xuhui; Feeley, Brian T

2015-07-01

Rotator cuff tears (RCTs) are among the most common musculoskeletal injuries seen by orthopaedic surgeons. Clinically, massive cuff tears lead to unique pathophysiological changes in rotator cuff muscle, including atrophy, and massive fatty infiltration, which are rarely seen in other skeletal muscles. Studies in a rodent model for RCT have demonstrated that these histologic findings are accompanied by activation of the Akt/mammalian target of rapamycin (mTOR) and transforming growth factor-β (TGF-β) pathways following combined tendon-nerve injury. The purpose of this study was to compare the histologic and molecular features of rotator cuff muscle and gastrocnemius muscle--a major hindlimb muscle, following combined tendon-nerve injury. Six weeks after injury, the rat gastrocnemius did not exhibit notable fatty infiltration compared to the rotator cuff. Likewise, the adipogenic markers SREBP-1 and PPARγ as well as the TGF-β canonical pathway were upregulated in the rotator cuff, but not the gastrocnemius. Our study suggests that the rat rotator cuff and hindlimb muscles differ significantly in their response to a combined tendon-nerve injury. Clinically, these findings highlight the unique response of the rotator cuff to injury, and may begin to explain the poor outcomes of massive RCTs compared to other muscle-tendon injuries. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Osteopontin deficiency delays inflammatory infiltration and the onset of muscle regeneration in a mouse model of muscle injury

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Kitipong Uaesoontrachoon

2013-01-01

Osteopontin is secreted by skeletal muscle myoblasts and stimulates their proliferation. Expression of osteopontin in skeletal muscle is upregulated in pathological conditions including Duchenne muscular dystrophy, and recent evidence suggests that osteopontin might influence the course of this disease. The current study was undertaken to determine whether osteopontin regulates skeletal muscle regeneration. A whole muscle autografting model of regeneration in osteopontin-null and wild-type mice was used. Osteopontin expression was found to be strongly upregulated in wild-type grafts during the initial degeneration and subsequent early regeneration phases that are observed in this model. Grafted muscle from osteopontin-null mice degenerated more slowly than that of wild-type mice, as determined by histological assessment, fibre diameter and fibre number. The delayed degeneration in osteopontin-null grafts was associated with a delay in neutrophil and macrophage infiltration. Centrally nucleated (regenerating muscle fibres also appeared more slowly in osteopontin-null grafts than in wild-type grafts. These results demonstrate that osteopontin plays a non-redundant role in muscle remodelling following injury.