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Sample records for striated muscle function

  1. Striated Muscle Function, Regeneration, and Repair

    Science.gov (United States)

    Shadrin, I.Y.; Khodabukus, A.; Bursac, N.

    2016-01-01

    As the only striated muscle tissues in the body, skeletal and cardiac muscle share numerous structural and functional characteristics, while exhibiting vastly different size and regenerative potential. Healthy skeletal muscle harbors a robust regenerative response that becomes inadequate after large muscle loss or in degenerative pathologies and aging. In contrast, the mammalian heart loses its regenerative capacity shortly after birth, leaving it susceptible to permanent damage by acute injury or chronic disease. In this review, we compare and contrast the physiology and regenerative potential of native skeletal and cardiac muscles, mechanisms underlying striated muscle dysfunction, and bioengineering strategies to treat muscle disorders. We focus on different sources for cellular therapy, biomaterials to augment the endogenous regenerative response, and progress in engineering and application of mature striated muscle tissues in vitro and in vivo. Finally, we discuss the challenges and perspectives in translating muscle bioengineering strategies to clinical practice. PMID:27271751

  2. In vivo functional and morphological characterization of bone and striated muscle microcirculation in NSG mice.

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    Haider Mussawy

    Full Text Available Organ-specific microcirculation plays a central role in tumor growth, tumor cell homing, tissue engineering, and wound healing. Mouse models are widely used to study these processes; however, these mouse strains often possess unique microhemodynamic parameters, making it difficult to directly compare experiments. The full functional characterization of bone and striated muscle microcirculatory parameters in non-obese diabetic-severe combined immunodeficiency/y-chain; NOD-Prkds IL2rg (NSG mice has not yet been reported. Here, we established either a dorsal skinfold chamber or femur window in NSG mice (n = 23, allowing direct analysis of microcirculatory parameters in vivo by intravital fluorescence microscopy at 7, 14, 21, and 28 days after chamber preparation. Organ-specific differences were observed. Bone had a significantly lower vessel density but a higher vessel diameter than striated muscle. Bone also showed higher effective vascular permeability than striated muscle. The centerline velocity values were similar in the femur window and dorsal skinfold chamber, with a higher volumetric blood flow in bone. Interestingly, bone and striated muscle showed similar tissue perfusion rates. Knowledge of physiological microhemodynamic values of bone and striated muscle in NSG mice makes it possible to analyze pathophysiological processes at these anatomic sites, such as tumor growth, tumor metastasis, and tumor microcirculation, as well as the response to therapeutic agents.

  3. The Popeye Domain Containing Genes and Their Function in Striated Muscle

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    Schindler, Roland F. R.; Scotton, Chiara; French, Vanessa; Ferlini, Alessandra; Brand, Thomas

    2016-01-01

    The Popeye domain containing (POPDC) genes encode a novel class of cAMP effector proteins, which are abundantly expressed in heart and skeletal muscle. Here, we will review their role in striated muscle as deduced from work in cell and animal models and the recent analysis of patients carrying a missense mutation in POPDC1. Evidence suggests that POPDC proteins control membrane trafficking of interacting proteins. Furthermore, we will discuss the current catalogue of established protein-protein interactions. In recent years, the number of POPDC-interacting proteins has been rising and currently includes ion channels (TREK-1), sarcolemma-associated proteins serving functions in mechanical stability (dystrophin), compartmentalization (caveolin 3), scaffolding (ZO-1), trafficking (NDRG4, VAMP2/3) and repair (dysferlin) or acting as a guanine nucleotide exchange factor for Rho-family GTPases (GEFT). Recent evidence suggests that POPDC proteins might also control the cellular level of the nuclear proto-oncoprotein c-Myc. These data suggest that this family of cAMP-binding proteins probably serves multiple roles in striated muscle. PMID:27347491

  4. Dynamic Regulation of Sarcomeric Actin Filaments in Striated Muscle

    OpenAIRE

    Ono, Shoichiro

    2010-01-01

    In striated muscle, the actin cytoskeleton is differentiated into myofibrils. Actin and myosin filaments are organized in sarcomeres and specialized for producing contractile forces. Regular arrangement of actin filaments with uniform length and polarity is critical for the contractile function. However, the mechanisms of assembly and maintenance of sarcomeric actin filaments in striated muscle are not completely understood. Live imaging of actin in striated muscle has revealed that actin sub...

  5. Systems Biology Approaches to Discerning Striated Muscle Pathologies

    OpenAIRE

    Mukund, Kavitha

    2016-01-01

    The human muscular system represents nearly 75% of the body mass and encompasses two major muscle forms- striated and smooth. Striated muscle, composed broadly of myofibers, accompanying membrane systems, cytoskeletal networks together with the metabolic and regulatory machinery, have revealed complexities in composition, structure and function. A disruption to any component within this complex system of interactions lead to disorders of the muscle, typically characterized by muscle fiber los...

  6. 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.

  7. Poorly Understood Aspects of Striated Muscle Contraction

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    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.

  8. S100A1: A Regulator of Striated Muscle Sarcoplasmic Reticulum Ca2+ Handling, Sarcomeric, and Mitochondrial Function

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    Mirko Völkers

    2010-01-01

    S100A1 has further been detected at different sites within the cardiac sarcomere indicating potential roles in myofilament function. More recently, a study reported a mitochondrial location of S100A1 in cardiomyocytes. Additionally, normalizing the level of S100A1 protein by means of viral cardiac gene transfer in animal heart failure models resulted in a disrupted progression towards cardiac failure and enhanced survival. This brief review is confined to the physiological and pathophysiological relevance of S100A1 in cardiac and skeletal muscle Ca2+ handling with a particular focus on its potential as a molecular target for future therapeutic interventions.

  9. Overexpression of TEAD-1 in transgenic mouse striated muscles produces a slower skeletal muscle contractile phenotype.

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    Tsika, Richard W; Schramm, Christine; Simmer, Gretchen; Fitzsimons, Daniel P; Moss, Richard L; Ji, Juan

    2008-12-26

    TEA domain (TEAD) transcription factors serve important functional roles during embryonic development and in striated muscle gene expression. Our previous work has implicated a role for TEAD-1 in the fast-to-slow fiber-type transition in response to mechanical overload. To investigate whether TEAD-1 is a modulator of slow muscle gene expression in vivo, we developed transgenic mice expressing hemagglutinin (HA)-tagged TEAD-1 under the control of the muscle creatine kinase promoter. We show that striated muscle-restricted HA-TEAD-1 expression induced a transition toward a slow muscle contractile protein phenotype, slower shortening velocity (Vmax), and longer contraction and relaxation times in adult fast twitch extensor digitalis longus muscle. Notably, HA-TEAD-1 overexpression resulted in an unexpected activation of GSK-3alpha/beta and decreased nuclear beta-catenin and NFATc1/c3 protein. These effects could be reversed in vivo by mechanical overload, which decreased muscle creatine kinase-driven TEAD-1 transgene expression, and in cultured satellite cells by TEAD-1-specific small interfering RNA. These novel in vivo data support a role for TEAD-1 in modulating slow muscle gene expression.

  10. Embracing change: striated-for-smooth muscle replacement in esophagus development.

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    Krauss, Robert S; Chihara, Daisuke; Romer, Anthony I

    2016-01-01

    The esophagus functions to transport food from the oropharyngeal region to the stomach via waves of peristalsis and transient relaxation of the lower esophageal sphincter. The gastrointestinal tract, including the esophagus, is ensheathed by the muscularis externa (ME). However, while the ME of the gastrointestinal tract distal to the esophagus is exclusively smooth muscle, the esophageal ME of many vertebrate species comprises a variable amount of striated muscle. The esophageal ME is initially composed only of smooth muscle, but its developmental maturation involves proximal-to-distal replacement of smooth muscle with striated muscle. This fascinating phenomenon raises two important questions: what is the developmental origin of the striated muscle precursor cells, and what are the cellular and morphogenetic mechanisms underlying the process? Studies addressing these questions have provided controversial answers. In this review, we discuss the development of ideas in this area and recent work that has shed light on these issues. A working model has emerged that should permit deeper understanding of the role of ME development and maturation in esophageal disorders and in the functional and evolutionary underpinnings of the variable degree of esophageal striated myogenesis in vertebrate species.

  11. Autoradiographic analysis of protein regeneration in striated skeleton muscle

    International Nuclear Information System (INIS)

    Dadoune, J.P.

    1977-01-01

    An autoradiographic study was conducted of protein regeneration in striated muscles aimed at clarifying the contradictions in the literature: while some authors hold that the regeneration rate is identical for all types of myofibril proteins and the myofibril is thus regenerated as a whole, others claim that the regeneration rate differs depending on the type of the myofibril protein. Tritium-labelled leucine incorporation experiments showed the existence of at least 2 pools of newly formed proteins in striated muscles in both adult and young animals. One pool is regenerated in 1 to 2 weeks, the other roughly in a month. The regeneration of proteins is initially more significant in red fibres; thus the rate of myofibril protein regeneration is not uniform. In adult animals regeneration seems to be slower in filaments than in the sarcoplasm and in the mitochondria. (A.K.)

  12. 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

  13. Expression of various sarcomeric tropomyosin isoforms in equine striated muscles

    OpenAIRE

    Dube, Syamalima; Chionuma, Henry; Matoq, Amr; Alshiekh-Nasany, Ruham; Abbott, Lynn; Poiesz, Bernard J.; Dube, Dipak K.

    2017-01-01

    In order to better understand the training and athletic activity of horses, we must have complete understanding of the isoform diversity of various myofibrillar protein genes like tropomyosin. Tropomyosin (TPM), a coiled-coil dimeric protein, is a component of thin filament in striated muscles. In mammals, four TPM genes (TPM1, TPM2, TPM3, and TPM4) generate a multitude of TPM isoforms via alternate splicing and/or using different promoters. Unfortunately, our knowledge of TPM isoform diversi...

  14. Expression of various sarcomeric tropomyosin isoforms in equine striated muscles

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    Syamalima Dube

    2017-06-01

    Full Text Available In order to better understand the training and athletic activity of horses, we must have complete understanding of the isoform diversity of various myofibrillar protein genes like tropomyosin. Tropomyosin (TPM, a coiled-coil dimeric protein, is a component of thin filament in striated muscles. In mammals, four TPM genes (TPM1, TPM2, TPM3, and TPM4 generate a multitude of TPM isoforms via alternate splicing and/or using different promoters. Unfortunately, our knowledge of TPM isoform diversity in the horse is very limited. Hence, we undertook a comprehensive exploratory study of various TPM isoforms from horse heart and skeletal muscle. We have cloned and sequenced two sarcomeric isoforms of the TPM1 gene called TPM1α and TPM1κ, one sarcomeric isoform of the TPM2 and one of the TPM3 gene, TPM2α and TPM3α respectively. By qRT-PCR using both relative expression and copy number, we have shown that TPM1α expression compared to TPM1κ is very high in heart. On the other hand, the expression of TPM1α is higher in skeletal muscle compared to heart. Further, the expression of TPM2α and TPM3α are higher in skeletal muscle compared to heart. Using western blot analyses with CH1 monoclonal antibody we have shown the high expression levels of sarcomeric TPM proteins in cardiac and skeletal muscle. Due to the paucity of isoform specific antibodies we cannot specifically detect the expression of TPM1κ in horse striated muscle. To the best of our knowledge this is the very first report on the characterization of sarcmeric TPMs in horse striated muscle.

  15. Embracing change: striated-for-smooth muscle replacement in esophagus development

    OpenAIRE

    Krauss, Robert S.; Chihara, Daisuke; Romer, Anthony I.

    2016-01-01

    The esophagus functions to transport food from the oropharyngeal region to the stomach via waves of peristalsis and transient relaxation of the lower esophageal sphincter. The gastrointestinal tract, including the esophagus, is ensheathed by the muscularis externa (ME). However, while the ME of the gastrointestinal tract distal to the esophagus is exclusively smooth muscle, the esophageal ME of many vertebrate species comprises a variable amount of striated muscle. The esophageal ME is initia...

  16. Muscle lim protein isoform negatively regulates striated muscle actin dynamics and differentiation.

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    Vafiadaki, Elizabeth; Arvanitis, Demetrios A; Papalouka, Vasiliki; Terzis, Gerasimos; Roumeliotis, Theodoros I; Spengos, Konstantinos; Garbis, Spiros D; Manta, Panagiota; Kranias, Evangelia G; Sanoudou, Despina

    2014-07-01

    Muscle lim protein (MLP) has emerged as a critical regulator of striated muscle physiology and pathophysiology. Mutations in cysteine and glycine-rich protein 3 (CSRP3), the gene encoding MLP, have been directly associated with human cardiomyopathies, whereas aberrant expression patterns are reported in human cardiac and skeletal muscle diseases. Increasing evidence suggests that MLP has an important role in both myogenic differentiation and myocyte cytoarchitecture, although the full spectrum of its intracellular roles has not been delineated. We report the discovery of an alternative splice variant of MLP, designated as MLP-b, showing distinct expression in neuromuscular disease and direct roles in actin dynamics and muscle differentiation. This novel isoform originates by alternative splicing of exons 3 and 4. At the protein level, it contains the N-terminus first half LIM domain of MLP and a unique sequence of 22 amino acids. Physiologically, it is expressed during early differentiation, whereas its overexpression reduces C2C12 differentiation and myotube formation. This may be mediated through its inhibition of MLP/cofilin-2-mediated F-actin dynamics. In differentiated striated muscles, MLP-b localizes to the sarcomeres and binds directly to Z-disc components, including α-actinin, T-cap and MLP. The findings of the present study unveil a novel player in muscle physiology and pathophysiology that is implicated in myogenesis as a negative regulator of myotube formation, as well as in differentiated striated muscles as a contributor to sarcomeric integrity. © 2014 FEBS.

  17. Compositional studies of myofibrils from rabbit striated muscle

    Energy Technology Data Exchange (ETDEWEB)

    Etlinger, J.D.; Zak, R.; Fischman, D.A.

    1976-01-01

    The localization of high-molecular-weight (80,000-200,000-daltons) proteins in the sarcomere of striated muscle has been studied by coordinated electron-microscopic and sodium dodecyl sulfate (SDS) gel electrophoretic analysis of native myofilaments and extracted and digested myofibrils. Methods were developed for the isolation of thick and thin filaments and of uncontracted myofibrils which are devoid of endoproteases and membrane fragments. Treatment of crude myofibrils with 0.5% Triton X-100 results in the release of a 110,000-dalton component without affecting the myofibrillar structure. Extraction of uncontracted myofibrils with a relaxing solution of high ionic strength results in the complete disappearance of the A band and M line. In this extract, five other protein bands in addition to myosin are resolved on SDS gels: bands M 1 (190,000 daltons) and M 2 (170,000 daltons), which are suggested to be components of the M line; M 3 (150,000 daltons), a degradation product; and a doublet M 4, M 5 (140,000 daltons), thick-filament protein having the same mobility as C protein.

  18. Overexpression of Striated Muscle Activator of Rho Signaling (STARS) Increases C2C12 Skeletal Muscle Cell Differentiation.

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    Wallace, Marita A; Della Gatta, Paul A; Ahmad Mir, Bilal; Kowalski, Greg M; Kloehn, Joachim; McConville, Malcom J; Russell, Aaron P; Lamon, Séverine

    2016-01-01

    Skeletal muscle growth and regeneration depend on the activation of satellite cells, which leads to myocyte proliferation, differentiation and fusion with existing muscle fibers. Skeletal muscle cell proliferation and differentiation are tightly coordinated by a continuum of molecular signaling pathways. The striated muscle activator of Rho signaling (STARS) is an actin binding protein that regulates the transcription of genes involved in muscle cell growth, structure and function via the stimulation of actin polymerization and activation of serum-response factor (SRF) signaling. STARS mediates cell proliferation in smooth and cardiac muscle models; however, whether STARS overexpression enhances cell proliferation and differentiation has not been investigated in skeletal muscle cells. We demonstrate for the first time that STARS overexpression enhances differentiation but not proliferation in C2C12 mouse skeletal muscle cells. Increased differentiation was associated with an increase in the gene levels of the myogenic differentiation markers Ckm, Ckmt2 and Myh4, the differentiation factor Igf2 and the myogenic regulatory factors (MRFs) Myf5 and Myf6. Exposing C2C12 cells to CCG-1423, a pharmacological inhibitor of SRF preventing the nuclear translocation of its co-factor MRTF-A, had no effect on myotube differentiation rate, suggesting that STARS regulates differentiation via a MRTF-A independent mechanism. These findings position STARS as an important regulator of skeletal muscle growth and regeneration.

  19. Cannabinoid CB1 Receptors Are Localized in Striated Muscle Mitochondria and Regulate Mitochondrial Respiration

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    Juan Mendizabal-Zubiaga

    2016-10-01

    Full Text Available The cannabinoid type 1 (CB1 receptor is widely distributed in the brain and peripheral organs where it regulates cellular functions and metabolism. In the brain, CB1 is mainly localized on presynaptic axon terminals but is also found on mitochondria (mtCB1, where it regulates cellular respiration and energy production. Likewise, CB1 is localized on muscle mitochondria, but very little is known about it. The aim of this study was to further investigate in detail the distribution and functional role of mtCB1 in three different striated muscles. Immunoelectron microscopy for CB1 was used in skeletal muscles (gastrocnemius and rectus abdominis and myocardium from wild-type and CB1-KO mice. Functional assessments were performed in mitochondria purified from the heart of the mice and the mitochondrial oxygen consumption upon application of different acute delta-9-tetrahidrocannabinol (Δ9-THC concentrations (100 nM or 200 nM was monitored. About 26% of the mitochondrial profiles in gastrocnemius, 22% in the rectus abdominis and 17% in the myocardium expressed CB1. Furthermore, the proportion of mtCB1 versus total CB1 immunoparticles was about 60% in the gastrocnemius, 55% in the rectus abdominis and 78% in the myocardium. Importantly, the CB1 immunolabeling pattern disappeared in muscles of CB1-KO mice. Functionally, acute 100 nM or 200 nM THC treatment specifically decreased mitochondria coupled respiration between 12% and 15% in wild-type isolated mitochondria of myocardial muscles but no significant difference was noticed between THC treated and vehicle in mitochondria isolated from CB1-KO heart. Furthermore, gene expression of key enzymes involved in pyruvate synthesis, tricarboxylic acid (TCA cycle and mitochondrial respiratory chain was evaluated in the striated muscle of CB1-WT and CB1-KO. CB1-KO showed an increase in the gene expression of Eno3, Pkm2, and Pdha1, suggesting an increased production of pyruvate. In contrast, no significant

  20. Morphology of lesions in striated muscle fibres from the beige mouse

    DEFF Research Database (Denmark)

    Kirkeby, S

    1982-01-01

    Lesions in striated muscle fibres from the beige mouse are described at both the light- and electronmicroscopical levels. The muscles have two types of lesions, one is well defined cores in the fibres and the other is diffusely enlarged intermyofibrillar spaces (IMS). The cores can be filled...... with membrane-like structures or a fluffy unstructured material. In the areas with enlarged IMS comparatively few organelles are present and the muscle fibres seem to be fragmented....

  1. Chaperones and the Proteasome System: Regulating the Construction and Demolition of Striated Muscle

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    Casey Carlisle

    2017-12-01

    Full Text Available Protein folding factors (chaperones are required for many diverse cellular functions. In striated muscle, chaperones are required for contractile protein function, as well as the larger scale assembly of the basic unit of muscle, the sarcomere. The sarcomere is complex and composed of hundreds of proteins and the number of proteins and processes recognized to be regulated by chaperones has increased dramatically over the past decade. Research in the past ten years has begun to discover and characterize the chaperones involved in the assembly of the sarcomere at a rapid rate. Because of the dynamic nature of muscle, wear and tear damage is inevitable. Several systems, including chaperones and the ubiquitin proteasome system (UPS, have evolved to regulate protein turnover. Much of our knowledge of muscle development focuses on the formation of the sarcomere but recent work has begun to elucidate the requirement and role of chaperones and the UPS in sarcomere maintenance and disease. This review will cover the roles of chaperones in sarcomere assembly, the importance of chaperone homeostasis and the cooperation of chaperones and the UPS in sarcomere integrity and disease.

  2. Splicing transitions of the anchoring protein ENH during striated muscle development.

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    Ito, Jumpei; Hashimoto, Taiki; Nakamura, Sho; Aita, Yusuke; Yamazaki, Tomoko; Schlegel, Werner; Takimoto, Koichi; Maturana, Andrés D

    2012-05-04

    The ENH (PDLIM5) protein acts as a scaffold to tether various functional proteins at subcellular sites via PDZ and three LIM domains. Splicing of the ENH primary transcript generates various products with different repertories of protein interaction modules. Three LIM-containing ENH predominates in neonatal cardiac tissue, whereas LIM-less ENHs are abundant in adult hearts, as well as skeletal muscles. Here we examine the timing of splicing transitions of ENH gene products during postnatal heart development and C2C12 myoblast differentiation. Real-time PCR analysis shows that LIM-containing ENH1 mRNA is gradually decreased during postnatal heart development, whereas transcripts with the short exon 5 appear in the late postnatal period and continues to increase until at least one month after birth. The splicing transition from LIM-containing ENH1 to LIM-less ENHs is also observed during the early period of C2C12 differentiation. This transition correlates with the emergence of ENH transcripts with the short exon 5, as well as the expression of myogenin mRNA. In contrast, the shift from the short exon 5 to the exon 7 occurs in the late differentiation period. The timing of this late event corresponds to the appearance of mRNA for the skeletal myosin heavy chain MYH4. Thus, coordinated and stepwise splicing transitions result in the production of specific ENH transcripts in mature striated muscles. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. The Intriguing Dual Lattices of the Myosin Filaments in Vertebrate Striated Muscles: Evolution and Advantage

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    Pradeep K. Luther

    2014-12-01

    Full Text Available Myosin filaments in vertebrate striated muscle have a long roughly cylindrical backbone with cross-bridge projections on the surfaces of both halves except for a short central bare zone. In the middle of this central region the filaments are cross-linked by the M-band which holds them in a well-defined hexagonal lattice in the muscle A-band. During muscular contraction the M-band-defined rotation of the myosin filaments around their long axes influences the interactions that the cross-bridges can make with the neighbouring actin filaments. We can visualise this filament rotation by electron microscopy of thin cross-sections in the bare-region immediately adjacent to the M-band where the filament profiles are distinctly triangular. In the muscles of teleost fishes, the thick filament triangular profiles have a single orientation giving what we call the simple lattice. In other vertebrates, for example all the tetrapods, the thick filaments have one of two orientations where the triangles point in opposite directions (they are rotated by 60° or 180° according to set rules. Such a distribution cannot be developed in an ordered fashion across a large 2D lattice, but there are small domains of superlattice such that the next-nearest neighbouring thick filaments often have the same orientation. We believe that this difference in the lattice forms can lead to different contractile behaviours. Here we provide a historical review, and when appropriate cite recent work related to the emergence of the simple and superlattice forms by examining the muscles of several species ranging back to primitive vertebrates and we discuss the functional differences that the two lattice forms may have.

  4. Kinetic isoforms of intramembrane charge in intact amphibian striated muscle.

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    Huang, C L

    1996-04-01

    The effects of the ryanodine receptor (RyR) antagonists ryanodine and daunorubicin on the kinetic and steady-state properties of intramembrane charge were investigated in intact voltage-clamped frog skeletal muscle fibers under conditions that minimized time-dependent ionic currents. A hypothesis that RyR gating is allosterically coupled to configurational changes in dihydropyridine receptors (DHPRs) would predict that such interactions are reciprocal and that RyR modification should influence intramembrane charge. Both agents indeed modified the time course of charging transients at 100-200-microM concentrations. They independently abolished the delayed charging phases shown by q gamma currents, even in fibers held at fully polarized, -90-mV holding potentials; such waveforms are especially prominent in extracellular solutions containing gluconate. Charge movements consistently became exponential decays to stable baselines in the absence of intervening inward or other time-dependent currents. The steady-state charge transfers nevertheless remained equal through the ON and the OFF parts of test voltage steps. The charge-voltage function, Q(VT), shifted by approximately +10 mV, particularly through those test potentials at which delayed q gamma currents normally took place but retained steepness factors (k approximately 8.0 to 10.6 mV) that indicated persistent, steeply voltage-dependent q gamma contributions. Furthermore, both RyR antagonists preserved the total charge, and its variation with holding potential, Qmax (VH), which also retained similarly high voltage sensitivities (k approximately 7.0 to 9.0 mV). RyR antagonists also preserved the separate identities of q gamma and q beta species, whether defined by their steady-state voltage dependence or inactivation or pharmacological properties. Thus, tetracaine (2 mM) reduced the available steady-state charge movement and gave shallow Q(VT) (k approximately 14 to 16 mV) and Qmax (VH) (k approximately 14 to 17 m

  5. Increased hypoxia-inducible factor-1α in striated muscle of tumor-bearing mice.

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    Devine, Raymond D; Bicer, Sabahattin; Reiser, Peter J; Wold, Loren E

    2017-06-01

    Cancer cachexia is a progressive wasting disease resulting in significant effects on the quality of life and high mortality. Most studies on cancer cachexia have focused on skeletal muscle; however, the heart is now recognized as a major site of cachexia-related effects. To elucidate possible mechanisms, a proteomic study was performed on the left ventricles of colon-26 (C26) adenocarcinoma tumor-bearing mice. The results revealed several changes in proteins involved in metabolism. An integrated pathway analysis of the results revealed a common mediator in hypoxia-inducible factor-1α (HIF-1α). Work by other laboratories has shown that extensive metabolic restructuring in the C26 mouse model causes changes in gene expression that may be affected directly by HIF-1α, such as glucose metabolic genes. M-mode echocardiography showed progressive decline in heart function by day 19 , exhibited by significantly decreased ejection fraction and fractional shortening, along with posterior wall thickness. Using Western blot analysis, we confirmed that HIF-1α is significantly upregulated in the heart, whereas there were no changes in its regulatory proteins, prolyl hydroxylase domain-containing protein 2 (PHD2) and von Hippel-Lindau protein (VHL). PHD2 requires both oxygen and iron as cofactors for the hydroxylation of HIF-1α, marking it for ubiquination via VHL and subsequent destruction by the proteasome complex. We examined venous blood gas values in the tumor-bearing mice and found significantly lower oxygen concentration compared with control animals in the third week after tumor inoculation. We also examined select skeletal muscles to determine whether they are similarly affected. In the diaphragm, extensor digitorum longus, and soleus, we found significantly increased HIF-1α in tumor-bearing mice, indicating a hypoxic response, not only in the heart, but also in skeletal muscle. These results indicate that HIF-1α may contribute, in part, to the metabolic changes

  6. Striated muscle fiber size, composition and capillary density in diabetes in relation to neuropathy and muscle strength

    DEFF Research Database (Denmark)

    Andreassen, Christer Swan; Jensen, Jacob Malte; Jakobsen, Johannes

    2014-01-01

    OBJECTIVE: Diabetic polyneuropathy (DPN) leads to progressive loss of muscle strength in the lower extremities due to muscular atrophy. Changes in vascularization occur in diabetic striated muscle; however, the relationship between these changes and DPN is as yet unexplored. The aim of the present...... study was to evaluate histologic properties and capillarization of diabetic skeletal muscle in relation to DPN and muscle strength. METHODS: Twenty type 1 and 20 type 2 diabetic (T1D and T2D, respectively) patients underwent biopsy of the gastrocnemic muscle, isokinetic dynamometry at the ankle......, electrophysiological studies, clinical examination, and quantitative sensory examinations. Muscle biopsies were stained immunohistochemically and muscle fiber diameter, fiber type distribution, and capillary density determined. Twenty control subjects were also included in the study. RESULTS: No relationship was found...

  7. Isoform composition, gene expression and sarcomeric protein phosphorylation in striated muscle of mice after space flight

    Science.gov (United States)

    Vikhlyantsev, Ivan; Ulanova, Anna; Salmov, Nikolay; Gritsyna, Yulia; Bobylev, Alexandr; Rogachevsky, Vadim; Shenkman, Boris; Podlubnaya, Zoya

    Using RT-PCR and SDS-PAGE, changes in isoform composition, gene expression, titin and nebulin phosphorylation, as well as changes in isoform composition of myosin heavy chains in striated muscles of mice were studied after 30-day-long space flight onboard the Russian spacecraft “BION-M” No. 1. The muscle fibre-type shift from slow-to-fast was observed in m. gastrocnemius and m. tibialis anterior of animals from “Flight” group. A decrease in the content of the NT and N2A titin isoforms and nebulin in the skeletal muscles of animals from “Flight” group was found. Meanwhile, significant differences in gene expression of these proteins in skeletal muscles of mice from “Flight” and “Control” groups were not observed. Using Pro-Q Diamond stain, an increase in titin phosphorylation in m. gastrocnemius of mice from “Flight” group was detected. The content of the NT, N2BA and N2B titin isoforms in cardiac muscle of mice from “Flight” and “Control” groups did not differ, nevertheless an increase in titin gene expression in the myocardium of the “Flight” group animals was found. The observed changes will be discussed in the context of theirs role in contractile activity of striated muscles of mice in conditions of weightlessness. This work was supported by the Russian Foundation for Basic Research (grants No. 14-04-32240, 14-04-00112). Acknowledgement. We express our gratitude to the teams of Institute of Biomedical Problems RAS and “PROGRESS” Corporation involved in the preparation of the “BION-M” mission.

  8. Immunocytochemical electron microscopic study and western blot analysis of myosin, paramyosin and miniparamyosin in the striated muscle of the fruit fly Drosophila melanogaster and in obliquely striated and smooth muscles of the earthworm Eisenia foetida.

    Science.gov (United States)

    Royuela, M; Fraile, B; Cervera, M; Paniagua, R

    1997-04-01

    Miniparamyosin is a paramyosin isoform (55-60 kDa) that has been isolated in insects (Drosophila) and immunolocalized in several species of arthropods, molluscs, annelids and nematodes. In this study, the presence and distribution of this protein, in comparison with that of paramyosin and myosin, has been examined in the striated muscle (tergal depressor of trochanter) of Drosophila melanogaster, and the obliquely striated muscle (body wall) and the smooth muscle (outer layer of the pseudoheart) of the earthworm Eisenia foetida by means of immunocytochemical electron microscopic study and Western blot analysis miniparamyosin paramyosin and myosin antibodies from Drosophila. In the striated muscle of D. melanogaster, the three proteins were immunolocalized along the length of the thick filaments (A-bands). The distribution of immunogold particles along these filaments was uniform. The relative proportions miniparamyosin/paramyosin/myosin (calculated by counting the number of immunogold particles) were: 1/10/68. In the obliquely striated muscle of E. foetida, immunoreactions to the three proteins were also found in the thick filaments, and the relative proportions miniparamyosin/paramyosin/myosin were 1/2.4/6.9. However, whereas the distribution of both myosin and miniparamyosin along the thick filament length was uniform, paramyosin immunolabelling was more abundant in the extremes of thick filaments (the outer zones of A-bands in the obliquely striated muscle), where the thick filaments become thinner than in the centre (the central zone of A-bands), where these filaments are thicker. The relative proportions of paramyosin in the outer and of paramyosin in the central zones of A-bands were 4/1. This irregular distribution of paramyosin along the thick filament length might be actual but it may also be explained by the fusiform shape of thick filaments in the earthworm: assuming that paramyosin is covered by myosin, paramyosin antigens would be more exposed in the

  9. Revealing t-tubules in striated muscle with new optical super-resolution microscopy techniques

    Directory of Open Access Journals (Sweden)

    Isuru D. Jayasinghe

    2014-12-01

    Full Text Available The t-tubular system plays a central role in the synchronisation of calcium signalling and excitation-contraction coupling in most striated muscle cells. Light microscopy has been used for imaging t-tubules for well over 100 years and together with electron microscopy (EM, has revealed the three-dimensional complexities of the t-system topology within cardiomyocytes and skeletal muscle fibres from a range of species. The emerging super-resolution single molecule localisation microscopy (SMLM techniques are offering a near 10-fold improvement over the resolution of conventional fluorescence light microscopy methods, with the ability to spectrally resolve nanometre scale distributions of multiple molecular targets. In conjunction with the next generation of electron microscopy, SMLM has allowed the visualisation and quantification of intricate t-tubule morphologies within large areas of muscle cells at an unprecedented level of detail. In this paper, we review recent advancements in the t-tubule structural biology with the utility of various microscopy techniques. We outline the technical considerations in adapting SMLM to study t-tubules and its potential to further our understanding of the molecular processes that underlie the sub-micron scale structural alterations observed in a range of muscle pathologies.

  10. Detection of a troponin I-like protein in non-striated muscle of the tardigrades (water bears).

    Science.gov (United States)

    Obinata, Takashi; Ono, Kanako; Ono, Shoichiro

    2011-03-01

    Tardigrades, also known as water bears, have somatic muscle fibers that are responsible for movement of their body and legs. These muscle fibers contain thin and thick filaments in a non-striated pattern. However, the regulatory mechanism of muscle contraction in tardigrades is unknown. In the absence of extensive molecular and genomic information, we detected a protein of 31 kDa in whole lysates of tardigrades that cross-reacted with the antibody raised against nematode troponin I (TnI). TnI is a component of the troponin complex that regulates actin-myosin interaction in a Ca(2+)-dependent and actin-linked manner. This TnI-like protein was co-extracted with actin in a buffer containing ATP and EGTA, which is known to induce relaxation of a troponin-regulated contractile system. The TnI-like protein was specifically expressed in the somatic muscle fibers in adult animals and partially co-localized with actin filaments in a non-striated manner. Interestingly, the pharyngeal muscle did not express this protein. These observations suggest that the non-striated somatic muscle of tardigrades has an actin-linked and troponin-regulated system for muscle contraction.

  11. Large-scale Models Reveal the Two-component Mechanics of Striated Muscle

    Directory of Open Access Journals (Sweden)

    Robert Jarosch

    2008-12-01

    Full Text Available This paper provides a comprehensive explanation of striated muscle mechanics and contraction on the basis of filament rotations. Helical proteins, particularly the coiled-coils of tropomyosin, myosin and α-actinin, shorten their H-bonds cooperatively and produce torque and filament rotations when the Coulombic net-charge repulsion of their highly charged side-chains is diminished by interaction with ions. The classical “two-component model” of active muscle differentiated a “contractile component” which stretches the “series elastic component” during force production. The contractile components are the helically shaped thin filaments of muscle that shorten the sarcomeres by clockwise drilling into the myosin cross-bridges with torque decrease (= force-deficit. Muscle stretch means drawing out the thin filament helices off the cross-bridges under passive counterclockwise rotation with torque increase (= stretch activation. Since each thin filament is anchored by four elastic α-actinin Z-filaments (provided with forceregulating sites for Ca2+ binding, the thin filament rotations change the torsional twist of the four Z-filaments as the “series elastic components”. Large scale models simulate the changes of structure and force in the Z-band by the different Z-filament twisting stages A, B, C, D, E, F and G. Stage D corresponds to the isometric state. The basic phenomena of muscle physiology, i. e. latency relaxation, Fenn-effect, the force-velocity relation, the length-tension relation, unexplained energy, shortening heat, the Huxley-Simmons phases, etc. are explained and interpreted with the help of the model experiments.

  12. (−)-EPICATECHIN IMPROVES MITOCHONDRIAL RELATED PROTEIN LEVELS AND AMELIORATES OXIDATIVE STRESS IN DYSTROPHIC DELTA SARCOGLYCAN NULL MOUSE STRIATED MUSCLE

    Science.gov (United States)

    Ramirez-Sanchez, Israel; De los Santos, Sergio; Gonzalez-Basurto, Silvia; Canto, Patricia; Mendoza-Lorenzo, Patricia; Palma-Flores, Carlos; Ceballos-Reyes, Guillermo; Villarreal, Francisco; Zentella-Dehesa, Alejandro; Coral-Vazquez, Ramon

    2014-01-01

    Muscular dystrophies (MD) are a group of heterogeneous genetic disorders characterized by progressive striated muscle wasting and degeneration. Although the genetic basis for many of these disorders has been identified, the exact mechanism for disease pathogenesis remains unclear. The presence of oxidative stress (OS) is known to contribute to the pathophysiology and severity of the MD. Mitochondrial dysfunction is observed in MD and likely represents an important determinant of increased OS. Experimental antioxidant therapies have been implemented with the aim of protecting against disease progression, but results from clinical trials have been disappointing. In this study, we explored the capacity of the cacao flavonoid (−)-epicatechin (Epi) to mitigate OS by acting as a positive regulator of mitochondrial structure/function endpoints and redox balance control systems in skeletal and cardiac muscles of dystrophic, δ-sarcoglycan (δ-SG) null mice. Wild type or δ-SG null 2.5 month old male mice were treated via oral gavage with either water (control animals) or Epi (1 mg/kg, twice/day) for 2 weeks. Results evidence a significant normalization of total protein carbonylation, recovery of reduced/oxidized glutathione (GSH/GSSG ratio) and enhanced superoxide dismutase 2, catalase and citrate synthase activities with Epi treatment. These effects were accompanied by increases in protein levels for thiolredoxin, glutathione peroxidase, superoxide dismutase 2, catalase and mitochondrial endpoints. Furthermore, we evidence decreases in heart and skeletal muscle fibrosis, accompanied with an improvement in skeletal muscle function with treatment. These results warrant the further investigation of Epi as a potential therapeutic agent to mitigate MD associated muscle degeneration. PMID:25284161

  13. VAPB/ALS8 MSP ligands regulate striated muscle energy metabolism critical for adult survival in caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Sung Min Han

    Full Text Available Mutations in VAPB/ALS8 are associated with amyotrophic lateral sclerosis (ALS and spinal muscular atrophy (SMA, two motor neuron diseases that often include alterations in energy metabolism. We have shown that C. elegans and Drosophila neurons secrete a cleavage product of VAPB, the N-terminal major sperm protein domain (vMSP. Secreted vMSPs signal through Roundabout and Lar-like receptors expressed on striated muscle. The muscle signaling pathway localizes mitochondria to myofilaments, alters their fission/fusion balance, and promotes energy production. Here, we show that neuronal loss of the C. elegans VAPB homolog triggers metabolic alterations that appear to compensate for muscle mitochondrial dysfunction. When vMSP levels drop, cytoskeletal or mitochondrial abnormalities in muscle induce elevated DAF-16, the Forkhead Box O (FoxO homolog, transcription factor activity. DAF-16 promotes muscle triacylglycerol accumulation, increases ATP levels in adults, and extends lifespan, despite reduced muscle mitochondria electron transport chain activity. Finally, Vapb knock-out mice exhibit abnormal muscular triacylglycerol levels and FoxO target gene transcriptional responses to fasting and refeeding. Our data indicate that impaired vMSP signaling to striated muscle alters FoxO activity, which affects energy metabolism. Abnormalities in energy metabolism of ALS patients may thus constitute a compensatory mechanism counterbalancing skeletal muscle mitochondrial dysfunction.

  14. Distribution of Myosin Attachment Times Predicted from Viscoelastic Mechanics of Striated Muscle

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    Bradley M. Palmer

    2011-01-01

    Full Text Available We demonstrate that viscoelastic mechanics of striated muscle, measured as elastic and viscous moduli, emerge directly from the myosin crossbridge attachment time, tatt, also called time-on. The distribution of tatt was modeled using a gamma distribution with shape parameter, p, and scale parameter, β. At 5 mM MgATP, β was similar between mouse α-MyHC (16.0±3.7 ms and β-MyHC (17.9±2.0 ms, and p was higher (P<0.05 for β-MyHC (5.6±0.4 no units compared to α-MyHC (3.2±0.9. At 1 mM MgATP, p approached a value of 10 in both isoforms, but β rose only in the β-MyHC (34.8±5.8 ms. The estimated mean tatt (i.e., pβ product was longer in the β-MyHC compared to α-MyHC, and became prolonged in both isoforms as MgATP was reduced as expected. The application of our viscoelastic model to these isoforms and varying MgATP conditions suggest that tatt is better modeled as a gamma distribution due to its representing multiple temporal events occurring within tatt compared to a single exponential distribution which assumes only one temporal event within tatt.

  15. Testosterone enhances C-14 2-deoxyglucose uptake by striated muscle. [sex hormones and muscle

    Science.gov (United States)

    Toop, J.; Max, S. R.

    1982-01-01

    The effect of testosterone propionate (TP) on C-14 2-deoxyglucose (C-14 2DG) uptake was studied in the rat levator ani muscle in vivo using the autoradiographic technique. Following a delay of 1 to 3 h after injecting TP, the rate of C-14 2DG uptake in experimental animals began to increase and continued to increase for at least 20 h. The label, which corresponds to C-14 2-deoxyglucose 6-phosphate, as demonstrated by chromatographic analysis of muscle extracts, was uniformly distributed over the entire muscle and was predominantly in muscle fibers, although nonmuscular elements were also labeled. The 1 to 3 h time lag suggests that the TP effect may be genomic, acting via androgen receptors, rather than directly on muscle membranes. Acceleration of glucose uptake may be an important early event in the anabolic response of the rat levator ani muscle to androgens.

  16. Immunocytochemical electron microscopic study and Western blot analysis of caldesmon and calponin in striated muscle of the fruit fly Drosophila melanogaster and in several muscle cell types of the earthworm Eisenia foetida.

    Science.gov (United States)

    Royuela, M; Fraile, B; Picazo, M L; Paniagua, R

    1997-01-01

    Caldesmon and calponin are two proteins that are characteristic of vertebrate smooth muscle. In invertebrates, caldesmon has only been studied in some molluscan muscles, and no previous references to calponin have been found. The aim of this paper was to investigate the presence and distribution of caldesmon and calponin in several invertebrate muscle cell types, classified according to their ultrastructural pattern: transversely striated muscle (flight muscle from Drosophila melanogaster), obliquely striated muscle (muscular body wall and inner muscular layer of the pseudoheart from the earthworm Eisenia foetida), and a muscle of doubtful classification which seems to be intermediate between smooth muscle and obliquely striated muscle (outer muscular layer of the pseudoheart, from E. foetida), using electron microscopy immunocytochemistry and Western blot analysis. Immunoreactions to both caldesmon and calponin were observed in the outer muscular layer cells from the earthworm pseudoheart but neither in the transversely striated muscle of D. melanogaster nor in the obliquely striated muscle from the earthworm. Present findings suggest that caldesmon- and calponin-like proteins are also present in invertebrate muscle cells, but only in those that are ultrastructurally similar to the vertebrate smooth muscle cells. Since discrepancies in the classification of some invertebrate muscles are common in the literature, the use of distinctive markers, such as troponin, caldesmon and calponin may improve our understanding of the nature and properties of many invertebrate muscles showing an ultrastructural pattern that does not resemble any of the classic muscle types.

  17. Contracture Coupling of Slow Striated Muscle in Non-Ionic Solutions and Replacement of Calcium, Sodium, and Potassium

    Science.gov (United States)

    Irwin, Richard L.; Hein, Manfred M.

    1964-01-01

    The development of contracture related to changes of ionic environment (ionic contracture coupling) has been studied in the slowly responding fibers of frog skeletal muscle. When deprived of external ions for 30 minutes by use of solutions of sucrose, mannitol, or glucose, the slow skeletal muscle fibers, but not the fast, develop pronounced and easily reversible contractures. Partial replacement of the non-ionic substance with calcium or sodium reduces the development of the contractures but replacement by potassium does not. The concentration of calcium necessary to prevent contracture induced by a non-ionic solution is greater than that needed to maintain relaxation in ionic solutions. To suppress the non-ionic-induced contractures to the same extent as does calcium requires several fold higher concentrations of sodium. Two types of ionic contracture coupling occur in slow type striated muscle fibers: (a) a calcium deprivation type which develops maximally at full physiological concentration of external sodium, shows a flow rate dependency for the calcium-depriving fluid, and is lessened when the sodium concentration is decreased by replacement with sucrose; (b) a sodium deprivation type which occurs maximally without external sodium, is lessened by increasing the sodium concentration, and has no flow rate dependency for ion deprivation. Both types of contracture are largely prevented by the presence of sufficient calcium. There thus seem to be calcium- and sodium-linked processes at work in the ionic contracture coupling of slow striated muscle. PMID:14127603

  18. The ‘Goldilocks Zone’ from a redox perspective - Adaptive versus deleterious responses to oxidative stress in striated muscle

    Directory of Open Access Journals (Sweden)

    Rick J Alleman

    2014-09-01

    Full Text Available Consequences of oxidative stress may be beneficial or detrimental in physiological systems. An organ system’s position on the ‘hormetic curve’ is governed by the source and temporality of reactive oxygen species (ROS production, proximity of ROS to moieties most susceptible to damage, and the capacity of the endogenous cellular ROS scavenging mechanisms. Most importantly, the resilience of the tissue (the capacity to recover from damage is a decisive factor, and this is reflected in the disparate response to ROS in cardiac and skeletal muscle. In myocytes, a high oxidative capacity invariably results in a significant ROS burden which in homeostasis, is rapidly neutralized by the robust antioxidant network. The up-regulation of key pathways in the antioxidant network is a central component of the hormetic response to ROS. Despite such adaptations, persistent oxidative stress over an extended time-frame (e.g. months to years inevitably leads to cumulative damages, maladaptation and ultimately the pathogenesis of chronic diseases. Indeed, persistent oxidative stress in heart and skeletal muscle has been repeatedly demonstrated to have causal roles in the etiology of heart disease and insulin resistance, respectively. Deciphering the mechanisms that underlie the divergence between adaptive and maladaptive responses to oxidative stress remains an active area of research for basic scientists and clinicians alike, as this would undoubtedly lead to novel therapeutic approaches. Here, we provide an overview of major types of ROS in striated muscle and the divergent adaptations that occur in response to them. Emphasis is placed on highlighting newly uncovered areas of research on this topic, with particular focus on the mitochondria, and the diverging roles that ROS play in muscle health (e.g., exercise or preconditioning and disease (e.g., cardiomyopathy, ischemia, metabolic syndrome.

  19. Creatine kinase deficiency in striated mouse muscle : biochemical and physiological studies

    NARCIS (Netherlands)

    Veld, Frank ter

    2003-01-01

    The balance between ATP energy demand and supply is essential in muscle cells. The creatine kinase system fulfils both a transporting and buffering role in muscle cells, whereby fluctuations in ATP free-energy demand can be counterbalanced. Removal of the creatine kinase proteins with the aid of

  20. Histochemical studies on striated muscle fibres of the beige mutant mouse

    DEFF Research Database (Denmark)

    Kirkeby, S

    1982-01-01

    A histological study of cylindric structures in skeletal muscle fibres from beige mice with the Chediak-Higashi syndrome was carried out. The muscle tissue was investigated morphologically with a differential interference contrast microscope and stained for glycogen, lipid, and basophile elements...

  1. Esterases in striated muscle from mice with the Chediak-Higashi syndrome

    DEFF Research Database (Denmark)

    Kirkeby, S; Moe, D

    1981-01-01

    In this paper a localized strong reaction for non-specific esterase forming cylindric structures is described within skeletal muscle fibres from the beige mouse. It seems from zymograms and protein electrophoresis that this esterase is membrane bound, highly reactive and present in rather small...... amounts within the muscle fibres....

  2. Development of Trichosomoides nasalis (Nematoda: Trichinelloidea) in the murid host: evidence for larval growth in striated muscle fibres

    Science.gov (United States)

    Fall, E.H.; Diagne, M.; Junker, K.; Duplantier, J.M.; Ba, K.; Vallée, I.; Bain, O.

    2012-01-01

    Trichosomoides nasalis (Trichinelloidea) is a parasite of Arvicanthis niloticus (Muridae) in Senegal. Female worms that harbour dwarf males in their uteri, occur in the epithelium of the nasal mucosa. Young laboratory-bred A. niloticus were either fed females containing larvated eggs or intraperitoneally injected with motile first-stage larvae recovered from female uteri. Both resulted in successful infection. Organs examined during rodent necropsy were blood and lymphatic circulatory systems (heart, large vessels, lymphnodes), lungs, liver, kidneys, thoracic and abdominal cavities, thoracic and abdominal muscular walls, diaphragm, tongue, and nasal mucosa. Development to adult nasal stages took three weeks. Recovery of newly hatched larvae from the peritoneal fluid at four-eight hours after oral infection suggests a direct passage from the stomach or intestinal wall to the musculature. However, dissemination through the blood, as observed with Trichinella spiralis, cannot be excluded even though newly hatched larvae of T. nasalis are twice as thick (15 μm). Developing larvae were found in histological sections of the striated muscle of the abdominal and thoracic walls, and larvae in fourth moult were dissected from these sites. Adult females were found in the deep nasal mucosa where mating occurred prior to worms settling in the nasal epithelium. The present study shows a remarkable similarity between T. nasalis and Trichinella species regarding muscle tropism, but the development of T. nasalis is not arrested at the late first-larval stage and does not induce transformation of infected fibres into nurse cells. T. nasalis seems a potential model to study molecular relations between trichinelloid larvae and infected muscle fibres. PMID:22314237

  3. Wheelchair marathon racing causes striated muscle distress in individuals with spinal cord injury.

    Science.gov (United States)

    Ide, M; Tajima, F; Furusawa, K; Mizushima, T; Ogata, H

    1999-03-01

    To assess the effects of wheelchair marathon racing in individuals with spinal cord injury (SCI) on circulating muscle enzymes and myoglobin. Thirty-one men with SCI, including 25 wheelchair marathon athletes and 6 sedentary men. Serum myoglobin (Mb), creatine kinase (CK) activity, and lactate dehydrogenase (LDH) were measured in participants of the 1995 Oita International Wheelchair Marathon Race (42.195 km). Blood samples were obtained 24 hours before, immediately after, 24 hours after, and 7 days after the race. Marathon racing resulted in significant increases in serum Mb, total CK activity, and LDH (pathletes with SCI. Completion of the marathon race did not cause cardiac muscle damage, however. Elevated muscle enzyme levels likely resulted from muscle distress rather than from dehydration.

  4. Impaired contractility of the circular striated urethral sphincter muscle may contribute to stress urinary incontinence in female zucker fatty rats.

    Science.gov (United States)

    Lee, Yung-Chin; Lin, Guiting; Wang, Guifang; Reed-Maldonado, Amanda; Lu, Zhihua; Wang, Lin; Banie, Lia; Lue, Tom F

    2017-08-01

    Obesity has been an independent risk factor for female stress urinary incontinence (SUI), the mechanism of this association remains unknown. The aim of this study is to validate the hypothesis that urethral dysfunction is a possible contributor to SUI in obese women. Ten Zucker Fatty (ZF) (ZUC-Lepr fa 185) and 10 Zucker Lean (ZL) (ZUC-Lepr fa 186) female rats at 12-week-old were used in this experiment. The urethral sphincter rings were harvested from the bladder neck through to the most proximal 2/3 regions. In the organ bath study, single pulses of electrical field stimulation (EFS) were applied. For the fatiguing stimulation, repeated multi-pulse EFS with 70 mA were applied at frequency of 5 Hz for 5 min. Caffeine-containing Krebs' solution was administrated to contract the urethra until the contraction began to reach a plateau for 10 min. We performed immunofluorescence staining of the urethra after the experiment was finished. Compared to ZL controls, ZF rats had significantly impaired muscle contractile activity (MCA) (P female rats had significantly impaired contractile properties of striated urethral sphincter, suggesting urethral dysfunction could be an important contributor to SUI in obesity. © 2016 Wiley Periodicals, Inc.

  5. Impact of a nickel-reduced stainless steel implant on striated muscle microcirculation: a comparative in vivo study.

    Science.gov (United States)

    Kraft, C N; Burian, B; Perlick, L; Wimmer, M A; Wallny, T; Schmitt, O; Diedrich, O

    2001-12-05

    The impairment of skeletal muscle microcirculation by a biomaterial may have profound consequences. With moderately good physical and corrosion characteristics, implant-quality stainless steel is particularly popular in orthopedic surgery. However, due to the presence of a considerable amount of nickel in the alloy, concern has been voiced in respect to local tissue responses. More recently a stainless steel alloy with a significant reduction of nickel has become commercially available. We, therefore, studied in vivo nutritive perfusion and leukocytic response of striated muscle to this nickel-reduced alloy, and compared these results with those of the materials conventional stainless steel and titanium. Using the hamster dorsal skinfold chamber preparation and intravital microscopy, we could demonstrate that reduction of the nickel quantity in a stainless steel implant has a positive effect on local microvascular parameters. Although the implantation of a conventional stainless steel sample led to a distinct and persistent activation of leukocytes combined with disruption of the microvascular endothelial integrity, marked leukocyte extravasation, and considerable venular dilation, animals with a nickel-reduced stainless steel implant showed only a moderate increase of these parameters, with a clear tendency of recuperation. Titanium implants merely caused a transient increase of leukocyte-endothelial cell interaction within the first 120 min, and no significant change in macromolecular leakage, leukocyte extravasation, or venular diameter. Pending biomechanical and corrosion testing, nickel-reduced stainless steel may be a viable alternative to conventional implant-quality stainless steel for biomedical applications. Concerning tolerance by the local vascular system, titanium currently remains unsurpassed. Copyright 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 404-412, 2001

  6. Striated muscle activator of Rho signalling (STARS) is reduced in ageing human skeletal muscle and targeted by miR-628-5p.

    Science.gov (United States)

    Russell, A P; Wallace, M A; Kalanon, M; Zacharewicz, E; Della Gatta, P A; Garnham, A; Lamon, S

    2017-06-01

    The striated muscle activator of Rho signalling (STARS) is a muscle-specific actin-binding protein. The STARS signalling pathway is activated by resistance exercise and is anticipated to play a role in signal mechanotransduction. Animal studies have reported a negative regulation of STARS signalling with age, but such regulation has not been investigated in humans. Ten young (18-30 years) and 10 older (60-75 years) subjects completed an acute bout of resistance exercise. Gene and protein expression of members of the STARS signalling pathway and miRNA expression of a subset of miRNAs, predicted or known to target members of STARS signalling pathway, were measured in muscle biopsies collected pre-exercise and 2 h post-exercise. For the first time, we report a significant downregulation of the STARS protein in older subjects. However, there was no effect of age on the magnitude of STARS activation in response to an acute bout of exercise. Finally, we established that miR-628-5p, a miRNA regulated by age and exercise, binds to the STARS 3'UTR to directly downregulate its transcription. This study describes for the first time the resistance exercise-induced regulation of STARS signalling in skeletal muscle from older humans and identifies a new miRNA involved in the transcriptional control of STARS. © 2016 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.

  7. Role of mitochondria-cytoskeleton interactions in respiration regulation and mitochondrial organization in striated muscles.

    Science.gov (United States)

    Varikmaa, Minna; Bagur, Rafaela; Kaambre, Tuuli; Grichine, Alexei; Timohhina, Natalja; Tepp, Kersti; Shevchuk, Igor; Chekulayev, Vladimir; Metsis, Madis; Boucher, François; Saks, Valdur; Kuznetsov, Andrey V; Guzun, Rita

    2014-02-01

    The aim of this work was to study the regulation of respiration and energy fluxes in permeabilized oxidative and glycolytic skeletal muscle fibers, focusing also on the role of cytoskeletal protein tubulin βII isotype in mitochondrial metabolism and organization. By analyzing accessibility of mitochondrial ADP, using respirometry and pyruvate kinase-phosphoenolpyruvate trapping system for ADP, we show that the apparent affinity of respiration for ADP can be directly linked to the permeability of the mitochondrial outer membrane (MOM). Previous studies have shown that MOM permeability in cardiomyocytes can be regulated by VDAC interaction with cytoskeletal protein, βII tubulin. We found that in oxidative soleus skeletal muscle the high apparent Km for ADP is associated with low MOM permeability and high expression of non-polymerized βII tubulin. Very low expression of non-polymerized form of βII tubulin in glycolytic muscles is associated with high MOM permeability for adenine nucleotides (low apparent Km for ADP). © 2013.

  8. Protein Kinase CK2 Regulates Leukocyte-Endothelial Cell Interactions during Ischemia and Reperfusion in Striated Skin Muscle.

    Science.gov (United States)

    Ampofo, Emmanuel; Widmaier, Daniela; Montenarh, Mathias; Menger, Michael D; Laschke, Matthias W

    2016-01-01

    Ischemia and reperfusion (I/R) causes tissue injury by inflammatory processes. This involves the upregulation of endothelial surface proteins by phospho-regulated signaling pathways, resulting in enhanced interactions of leukocytes with endothelial cells. Recently, we found that protein kinase CK2 is a crucial regulator of leukocyte-mediated inflammation. Therefore, in this study we investigated the involvement of CK2 in leukocyte-endothelial cell interactions during I/R injury. We first analyzed the inhibitory action of (E)-3-(2,3,4,5-tetrabromophenyl)acrylic acid (TBCA) and CX-4945 on CK2 kinase activity and the viability of human dermal microvascular endothelial cells (HDMEC). To mimic I/R conditions in vitro, HDMEC were exposed to hypoxia and reoxygenation and the expression of adhesion molecules was analyzed by flow cytometry. Moreover, we analyzed in vivo the effect of CK2 inhibition on leukocyte-endothelial cell interactions in the dorsal skinfold chamber model of I/R injury by means of repetitive intravital fluorescence microscopy and immunohistochemistry. We found that TBCA and CX-4945 suppressed the activity of CK2 in HDMEC without affecting cell viability. This was associated with a significant downregulation of E-selectin and intercellular adhesion molecule (ICAM)-1 after in vitro hypoxia and reoxygenation. In vivo, CX-4945 treatment significantly decreased the numbers of adherent and transmigrated leukocytes in striated muscle tissue exposed to I/R. Our findings indicate that CK2 is involved in the regulation of leukocyte-endothelial cell interactions during I/R by mediating the expression of E-selectin and ICAM-1. © 2016 S. Karger AG, Basel.

  9. Structural studies of the waves in striated muscle fibres shortened passively below their slack length.

    Science.gov (United States)

    Brown, L M; González-Serratos, H; Huxley, A F

    1984-06-01

    Isolated skeletal muscle fibres of Rana pipiens were shortened below their slack length by longitudinal compression in a gelatine block, and examined by light and electron microscopy. Waves appeared sharply when the striation spacing (S) reached a critical value (about 2 microns) and increased in height with further compression down to S = 1.6 microns while the resting band pattern was maintained. The waves were plane, helical or irregular, with wave lengths of 5-15 striations. The Z lines usually ran perpendicular to the direction of the myofibrils to form wedge-shaped sarcomeres. The bending occurred mainly in the I band. The thin filaments ran stiffly for about 30 nm from the Z line and then bent toward the A band. The thick filaments bent very slightly, particularly at their tips. The edges of the A band were indistinct, and there were no dense lines at the A-I junction. The appearance of the individual sarcomeres resembled those in relaxed myofibrils at slack length, with no Cm bands. The H zone was only seen occasionally in the slack and wavy fibres examined. In very thin sections the individual thin filaments were seen to end in the pseudo-H zone, and not to cross the M line. There was a single array of not more than six thin filaments round each thick one in transverse sections of the M-line region. These observations suggest that the narrowing of the bands observed in fresh wavy fibres is due mainly to the obliquity of the myofibrils, and that the sarcomere length measured parallel to their axis is longer than the striation spacing. The relationship between sarcomere length and the length of the thin-filament complex is discussed.

  10. Comparative Biomechanics of Thick Filaments and Thin Filaments with Functional Consequences for Muscle Contraction

    Directory of Open Access Journals (Sweden)

    Mark S. Miller

    2010-01-01

    Full Text Available The scaffold of striated muscle is predominantly comprised of myosin and actin polymers known as thick filaments and thin filaments, respectively. The roles these filaments play in muscle contraction are well known, but the extent to which variations in filament mechanical properties influence muscle function is not fully understood. Here we review information on the material properties of thick filaments, thin filaments, and their primary constituents; we also discuss ways in which mechanical properties of filaments impact muscle performance.

  11. Isoform Composition and Gene Expression of Thick and Thin Filament Proteins in Striated Muscles of Mice after 30-Day Space Flight

    Directory of Open Access Journals (Sweden)

    Anna Ulanova

    2015-01-01

    Full Text Available Changes in isoform composition, gene expression of titin and nebulin, and isoform composition of myosin heavy chains as well as changes in titin phosphorylation level in skeletal (m. gastrocnemius, m. tibialis anterior, and m. psoas and cardiac muscles of mice were studied after a 30-day-long space flight onboard the Russian spacecraft “BION-M” number 1. A muscle fibre-type shift from slow-to-fast and a decrease in the content of titin and nebulin in the skeletal muscles of animals from “Flight” group was found. Using Pro-Q Diamond staining, an ~3-fold increase in the phosphorylation level of titin in m. gastrocnemius of mice from the “Flight” group was detected. The content of titin and its phosphorylation level in the cardiac muscle of mice from “Flight” and “Control” groups did not differ; nevertheless an increase (2.2 times in titin gene expression in the myocardium of flight animals was found. The observed changes are discussed in the context of their role in the contractile activity of striated muscles of mice under conditions of weightlessness.

  12. A functional magnetic resonance imaging investigation of visual hallucinations in the human striate cortex.

    Science.gov (United States)

    Abid, Hina; Ahmad, Fayyaz; Lee, Soo Y; Park, Hyun W; Im, Dongmi; Ahmad, Iftikhar; Chaudhary, Safee U

    2016-11-29

    Human beings frequently experience fear, phobia, migraine and hallucinations, however, the cerebral mechanisms underpinning these conditions remain poorly understood. Towards this goal, in this work, we aim to correlate the human ocular perceptions with visual hallucinations, and map them to their cerebral origins. An fMRI study was performed to examine the visual cortical areas including the striate, parastriate and peristriate cortex in the occipital lobe of the human brain. 24 healthy subjects were enrolled and four visual patterns including hallucination circle (HCC), hallucination fan (HCF), retinotopy circle (RTC) and retinotopy cross (RTX) were used towards registering their impact in the aforementioned visual related areas. One-way analysis of variance was used to evaluate the significance of difference between induced activations. Multinomial regression and and K-means were used to cluster activation patterns in visual areas of the brain. Significant activations were observed in the visual cortex as a result of stimulus presentation. The responses induced by visual stimuli were resolved to Brodmann areas 17, 18 and 19. Activation data clustered into independent and mutually exclusive clusters with HCC registering higher activations as compared to HCF, RTC and RTX. We conclude that small circular objects, in rotation, tend to leave greater hallucinating impressions in the visual region. The similarity between observed activation patterns and those reported in conditions such as epilepsy and visual hallucinations can help elucidate the cortical mechanisms underlying these conditions. Trial Registration 1121_GWJUNG.

  13. Tachykinins are involved in local reflex modulation of vagally mediated striated muscle contractions in the rat esophagus via tachykinin NK1 receptors.

    Science.gov (United States)

    Shiina, T; Shimizu, Y; Boudaka, A; Wörl, J; Takewaki, T

    2006-05-12

    The objective of the present study was to investigate the hypothesis of the presence of a local neural reflex modulating the vagally mediated contractions of striated muscle in the rat esophagus and to determine the possible involvement of tachykinins in such a local neural reflex. Electrical stimulation of the vagus nerve evoked twitch contractile responses that were abolished by d-tubocurarine (5 microM). Capsaicin (1-100 microM) inhibited the vagally mediated twitch contractions o f the normal rat esophageal preparations concentration-dependently but not those of the neonatally capsaicin-treated ones. NG-nitro-L-arginine methyl ester (100 microM), a nitric oxide synthase inhibitor, blocked the inhibitory effect of capsaicin and exogenous application of a nitric oxide donor (1 mM) inhibited the vagally mediated twitch contractions. Capsaicin suppressed acetylcholine release from the normal rat esophageal segments evoked by vagus nerve stimulation but not that from the neonatally capsaicin-treated ones. A selective tachykinin NK1 receptor antagonist (0.1 or 1 microM) attenuated the inhibitory effect of capsaicin. However, antagonists of tachykinin NK2, tachykinin NK3 and calcitonin gene-related peptide receptors (1 microM) did not have any effect. A tachykinin NK1 receptor agonist (1 or 5 microM) inhibited the vagally mediated twitch contractions, which was prevented by NG-nitro-L-arginine methyl ester (100 microM). These data suggest that the rat esophagus might have a local neural reflex inhibiting the vagally mediated striated muscle motility, which consists of capsaicin-sensitive sensory neurons and myenteric nitrergic neurons, and that tachykinins might be involved in the neural reflex through tachykinin NK1 receptors.

  14. Seasonal changes in isoform composition of giant proteins of thick and thin filaments and titin (connectin) phosphorylation level in striated muscles of bears (Ursidae, Mammalia).

    Science.gov (United States)

    Salmov, N N; Vikhlyantsev, I M; Ulanova, A D; Gritsyna, Yu V; Bobylev, A G; Saveljev, A P; Makariushchenko, V V; Maksudov, G Yu; Podlubnaya, Z A

    2015-03-01

    Seasonal changes in the isoform composition of thick and thin filament proteins (titin, myosin heavy chains (MyHCs), nebulin), as well as in the phosphorylation level of titin in striated muscles of brown bear (Ursus arctos) and hibernating Himalayan black bear (Ursus thibetanus ussuricus) were studied. We found that the changes that lead to skeletal muscle atrophy in bears during hibernation are not accompanied by a decrease in the content of nebulin and intact titin-1 (T1) isoforms. However, a decrease (2.1-3.4-fold) in the content of T2 fragments of titin was observed in bear skeletal muscles (m. gastrocnemius, m. longissimus dorsi, m. biceps) during hibernation. The content of the stiffer N2B titin isoform was observed to increase relative to the content of its more compliant N2BA isoform in the left ventricles of hibernating bears. At the same time, in spite of the absence of decrease in the total content of T1 in the myocardium of hibernating brown bear, the content of T2 fragments decreased ~1.6-fold. The level of titin phosphorylation only slightly increased in the cardiac muscle of hibernating brown bear. In the skeletal muscles of brown bear, the level of titin phosphorylation did not vary between seasons. However, changes in the composition of MyHCs aimed at increasing the content of slow (I) and decreasing the content of fast (IIa) isoforms of this protein during hibernation of brown bear were detected. Content of MyHCs I and IIa in the skeletal muscles of hibernating Himalayan black bear corresponded to that in the skeletal muscles of hibernating brown bear.

  15. Response of the JAK-STAT pathway to mammalian hibernation in 13-lined ground squirrel striated muscle.

    Science.gov (United States)

    Logan, Samantha M; Tessier, Shannon N; Tye, Joann; Storey, Kenneth B

    2016-03-01

    Over the course of the torpor-arousal cycle, hibernators must make behavioral, physiological, and molecular rearrangements in order to keep a very low metabolic rate and retain organ viability. 13-lined ground squirrels (Ictidomys tridecemlineatus) remain immobile during hibernation, and although the mechanisms of skeletal muscle survival are largely unknown, studies have shown minimal muscle loss in hibernating organisms. Additionally, the ground squirrel heart undergoes cold-stress, reversible cardiac hypertrophy, and ischemia-reperfusion without experiencing fatal impairment. This study examines the role of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway in the regulation of cell stress in cardiac and skeletal muscles, comparing euthermic and hibernating ground squirrels. Immunoblots showed a fivefold decrease in JAK3 expression during torpor in skeletal muscle, along with increases in STAT3 and 5 phosphorylation and suppressors of cytokine signaling-1 (SOCS1) protein levels. Immunoblots also showed coordinated increases in STAT1, 3 and 5 phosphorylation and STAT1 inhibitor protein expression in cardiac muscle during torpor. PCR analysis revealed that the activation of these pro-survival signaling cascades did not result in coordinate changes in downstream genes such as anti-apoptotic B-cell lymphoma-2 (Bcl-2) family gene expression. Overall, these results indicate activation of the JAK-STAT pathway in both cardiac and skeletal muscles, suggesting a response to cellular stress during hibernation.

  16. Standardization of metachromatic staining method of myofibrillar ATPase activity of myosin to skeletal striated muscle of mules and donkeys

    Directory of Open Access Journals (Sweden)

    Flora H.F. D'Angelis

    2014-09-01

    Full Text Available This study aims at standardizing the pre-incubation and incubation pH and temperature used in the metachromatic staining method of myofibrillar ATPase activity of myosin (mATPase used for asses and mules. Twenty four donkeys and 10 mules, seven females and three males, were used in the study. From each animal, fragments from the Gluteus medius muscle were collected and percutaneous muscle biopsy was performed using a 6.0-mm Bergström-type needle. In addition to the metachromatic staining method of mATPase, the technique of nicotinamide adenine dinucleotide tetrazolium reductase (NADH-TR was also performed to confirm the histochemical data. The histochemical result of mATPase for acidic pre-incubation (pH=4.50 and alkaline incubation (pH=10.50, at a temperature of 37ºC, yielded the best differentiation of fibers stained with toluidine blue. Muscle fibers were identified according to the following colors: type I (oxidative, light blue, type IIA (oxidative-glycolytic, intermediate blue and type IIX (glycolytic, dark blue. There are no reports in the literature regarding the characterization and distribution of different types of muscle fibers used by donkeys and mules when performing traction work, cargo transportation, endurance sports (horseback riding and marching competitions. Therefore, this study is the first report on the standardization of the mATPase technique for donkeys and mules.

  17. Multi-tasking role of the mechanosensing protein Ankrd2 in the signaling network of striated muscle.

    Directory of Open Access Journals (Sweden)

    Anna Belgrano

    Full Text Available Ankrd2 (also known as Arpp together with Ankrd1/CARP and DARP are members of the MARP mechanosensing proteins that form a complex with titin (N2A/calpain 3 protease/myopalladin. In muscle, Ankrd2 is located in the I-band of the sarcomere and moves to the nucleus of adjacent myofibers on muscle injury. In myoblasts it is predominantly in the nucleus and on differentiation shifts from the nucleus to the cytoplasm. In agreement with its role as a sensor it interacts both with sarcomeric proteins and transcription factors.Expression profiling of endogenous Ankrd2 silenced in human myotubes was undertaken to elucidate its role as an intermediary in cell signaling pathways. Silencing Ankrd2 expression altered the expression of genes involved in both intercellular communication (cytokine-cytokine receptor interaction, endocytosis, focal adhesion, tight junction, gap junction and regulation of the actin cytoskeleton and intracellular communication (calcium, insulin, MAPK, p53, TGF-β and Wnt signaling. The significance of Ankrd2 in cell signaling was strengthened by the fact that we were able to show for the first time that Nkx2.5 and p53 are upstream effectors of the Ankrd2 gene and that Ankrd1/CARP, another MARP member, can modulate the transcriptional ability of MyoD on the Ankrd2 promoter. Another novel finding was the interaction between Ankrd2 and proteins with PDZ and SH3 domains, further supporting its role in signaling. It is noteworthy that we demonstrated that transcription factors PAX6, LHX2, NFIL3 and MECP2, were able to bind both the Ankrd2 protein and its promoter indicating the presence of a regulatory feedback loop mechanism.In conclusion we demonstrate that Ankrd2 is a potent regulator in muscle cells affecting a multitude of pathways and processes.

  18. Microvascular response of striated muscle to metal debris. A comparative in vivo study with titanium and stainless steel.

    Science.gov (United States)

    Kraft, C N; Diedrich, O; Burian, B; Schmitt, O; Wimmer, M A

    2003-01-01

    Wear products of metal implants are known to induce biological events which may have profound consequences for the microcirculation of skeletal muscle. Using the skinfold chamber model and intravital microscopy we assessed microcirculatory parameters in skeletal muscle after confrontation with titanium and stainless-steel wear debris, comparing the results with those of bulk materials. Implantation of stainless-steel bulk and debris led to a distinct activation of leukocytes combined with a disruption of the microvascular endothelial integrity and massive leukocyte extravasation. While animals with bulk stainless steel showed a tendency to recuperation, stainless-steel wear debris induced such severe inflammation and massive oedema that the microcirculation broke down within 24 hours after implantation. Titanium bulk caused only a transient increase in leukocyte-endothelial cell interaction within the first 120 minutes and no significant change in macromolecular leakage, leukocyte extravasation or venular diameter. Titanium wear debris produced a markedly lower inflammatory reaction than stainless-steel bulk, indicating that a general benefit of bulk versus debris could not be claimed. Depending on its constituents, wear debris is capable of eliciting acute inflammation which may result in endothelial damage and subsequent failure of microperfusion. Our results indicate that not only the bulk properties of orthopaedic implants but also the microcirculatory implications of inevitable wear debris play a pivotal role in determining the biocompatibility of an implant.

  19. Mesodermal iPSC–derived progenitor cells functionally regenerate cardiac and skeletal muscle

    Science.gov (United States)

    Quattrocelli, Mattia; Swinnen, Melissa; Giacomazzi, Giorgia; Camps, Jordi; Barthélemy, Ines; Ceccarelli, Gabriele; Caluwé, Ellen; Grosemans, Hanne; Thorrez, Lieven; Pelizzo, Gloria; Muijtjens, Manja; Verfaillie, Catherine M.; Blot, Stephane; Janssens, Stefan; Sampaolesi, Maurilio

    2015-01-01

    Conditions such as muscular dystrophies (MDs) that affect both cardiac and skeletal muscles would benefit from therapeutic strategies that enable regeneration of both of these striated muscle types. Protocols have been developed to promote induced pluripotent stem cells (iPSCs) to differentiate toward cardiac or skeletal muscle; however, there are currently no strategies to simultaneously target both muscle types. Tissues exhibit specific epigenetic alterations; therefore, source-related lineage biases have the potential to improve iPSC-driven multilineage differentiation. Here, we determined that differential myogenic propensity influences the commitment of isogenic iPSCs and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages. Differential myogenic propensity did not influence pluripotency, but did selectively enhance chimerism of MiP-derived tissue in both fetal and adult skeletal muscle. When injected into dystrophic mice, MiPs engrafted and repaired both skeletal and cardiac muscle, reducing functional defects. Similarly, engraftment into dystrophic mice of canine MiPs from dystrophic dogs that had undergone TALEN-mediated correction of the MD-associated mutation also resulted in functional striatal muscle regeneration. Moreover, human MiPs exhibited the same capacity for the dual differentiation observed in murine and canine MiPs. The findings of this study suggest that MiPs should be further explored for combined therapy of cardiac and skeletal muscles. PMID:26571398

  20. Muscle RING‐finger 2 and 3 maintain striated‐muscle structure and function

    Science.gov (United States)

    Lodka, Dörte; Pahuja, Aanchal; Geers‐Knörr, Cornelia; Scheibe, Renate J.; Nowak, Marcel; Hamati, Jida; Köhncke, Clemens; Purfürst, Bettina; Kanashova, Tamara; Schmidt, Sibylle; Glass, David J.; Morano, Ingo; Heuser, Arnd; Kraft, Theresia; Bassel‐Duby, Rhonda; Olson, Eric N.; Dittmar, Gunnar; Sommer, Thomas

    2015-01-01

    Abstract Background The Muscle‐specific RING‐finger (MuRF) protein family of E3 ubiquitin ligases is important for maintenance of muscular structure and function. MuRF proteins mediate adaptation of striated muscles to stress. MuRF2 and MuRF3 bind to microtubules and are implicated in sarcomere formation with noticeable functional redundancy. However, if this redundancy is important for muscle function in vivo is unknown. Our objective was to investigate cooperative function of MuRF2 and MuRF3 in the skeletal muscle and the heart in vivo. Methods MuRF2 and MuRF3 double knockout mice (DKO) were generated and phenotypically characterized. Skeletal muscle and the heart were investigated by morphological measurements, histological analyses, electron microscopy, immunoblotting, and real‐time PCR. Isolated muscles were subjected to in vitro force measurements. Cardiac function was determined by echocardiography and working heart preparations. Function of cardiomyocytes was measured in vitro. Cell culture experiments and mass‐spectrometry were used for mechanistic analyses. Results DKO mice showed a protein aggregate myopathy in skeletal muscle. Maximal force development was reduced in DKO soleus and extensor digitorum longus. Additionally, a fibre type shift towards slow/type I fibres occurred in DKO soleus and extensor digitorum longus. MuRF2 and MuRF3‐deficient hearts showed decreased systolic and diastolic function. Further analyses revealed an increased expression of the myosin heavy chain isoform beta/slow and disturbed calcium handling as potential causes for the phenotype in DKO hearts. Conclusions The redundant function of MuRF2 and MuRF3 is important for maintenance of skeletal muscle and cardiac structure and function in vivo. PMID:27493870

  1. Structure, function and evolution of insect flight muscle

    OpenAIRE

    Iwamoto, Hiroyuki

    2011-01-01

    Insects, the largest group of animals on the earth, owe their prosperity to their ability of flight and small body sizes. The ability of flight provided means for rapid translocation. The small body size allowed access to unutilized niches. By acquiring both features, however, insects faced a new problem: They were forced to beat their wings at enormous frequencies. Insects have overcome this problem by inventing asynchronous flight muscle, a highly specialized form of striated muscle capable...

  2. Physical Rehabilitation Improves Muscle Function Following Volumetric Muscle Loss Injury

    Science.gov (United States)

    2014-12-19

    muscle , but it did so without significant morphological adaptations (e.g., no hypertrophy and hyperplasia). Wheel running up-regulated metabolic genes...been shown to foster regeneration of injured muscle [5,32,33] and promote hypertrophy (i.e., increased protein synthesis or muscle weight) in muscle ...remaining muscle tissue. Strengthening of synergist muscles can partially compensate for the loss of function due to VML injury. Compensatory hypertrophy

  3. Fiber types in the striated urethral and anal sphincters

    DEFF Research Database (Denmark)

    Schrøder, H D; Reske-Nielsen, E

    1983-01-01

    Seven normal human striated urethral and anal sphincters obtained by autopsy were examined using histochemical techniques. In both the urethral sphincter and the subcutaneous (s.c.) and superficial part of the anal sphincter a characteristic pattern with two populations of muscle fibers, abundant...

  4. Dose-dependent separation of the hypertrophic and myotoxic effects of the β2-adrenergic receptor agonist clenbuterol in rat striated muscles.

    Science.gov (United States)

    Burniston, Jatin G; WA, Clark; Tan, Lip-Bun; Goldspink, David F

    2007-01-01

    Muscle growth in response to large doses (i.e., mg.kg-1) of β2-adrenergic receptor agonists has been consistently reported. However, such doses may also induce myocyte death in the heart and skeletal muscles and hence may not be applicable safe doses for humans. Here, we report the hypertrophic and myotoxic effects of different doses of clenbuterol. Rats were infused with clenbuterol (range, 1 μg to 1 mg.kg-1) for 14 days. Muscle protein content, myofiber cross-sectional area and myocyte death were then investigated. Infusions of ≥10 μg.kg-1.d-1 of clenbuterol significantly (Pclenbuterol in the absence of myocyte death. PMID:16411205

  5. The evolutionary origin of bilaterian smooth and striated myocytes

    Science.gov (United States)

    Brunet, Thibaut; Fischer, Antje HL; Steinmetz, Patrick RH; Lauri, Antonella; Bertucci, Paola; Arendt, Detlev

    2016-01-01

    The dichotomy between smooth and striated myocytes is fundamental for bilaterian musculature, but its evolutionary origin is unsolved. In particular, interrelationships of visceral smooth muscles remain unclear. Absent in fly and nematode, they have not yet been characterized molecularly outside vertebrates. Here, we characterize expression profile, ultrastructure, contractility and innervation of the musculature in the marine annelid Platynereis dumerilii and identify smooth muscles around the midgut, hindgut and heart that resemble their vertebrate counterparts in molecular fingerprint, contraction speed and nervous control. Our data suggest that both visceral smooth and somatic striated myocytes were present in the protostome-deuterostome ancestor and that smooth myocytes later co-opted the striated contractile module repeatedly – for example, in vertebrate heart evolution. During these smooth-to-striated myocyte conversions, the core regulatory complex of transcription factors conveying myocyte identity remained unchanged, reflecting a general principle in cell type evolution. DOI: http://dx.doi.org/10.7554/eLife.19607.001 PMID:27906129

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

    Directory of Open Access Journals (Sweden)

    Matthew Emerson Randolph

    2015-10-01

    Full Text Available 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, 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 muscular dystrophies. The biology of muscle stem cells varies depending on their embryologic origins and 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.

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

    Science.gov (United States)

    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

  8. Optimizing calf muscle pump function.

    Science.gov (United States)

    Lattimer, Christopher R; Franceschi, Claude; Kalodiki, Evi

    2017-01-01

    Background The tip toe manoeuvre has been promoted as the gold standard plethysmography test for measuring calf muscle pump function. The aim was to compare the tip toe manoeuvre, dorsiflexion manoeuvre and a body weight transfer manoeuvre using the ejection fraction of air-plethysmography and evaluate which has the best pumping effect. Methods Sixty-six archived tracings on 22 legs were retrieved from an air-plethysmography workshop and analysed. Pumping performance was measured using the calf volume reduction after each manoeuvre. Results Expressed as median [inter-quartile range], body weight transfer manoeuvres resulted in a significantly greater ejection fraction (%) than tip toe manoeuvres at 59.7 [53.5-63.9] versus 42.6 [30.5-52.6], P calf muscle pump with a 40.1% relative increase in the ejection fraction compared to a tip toe manoeuvre. Exercises which involve body weight transfers from one leg to the other may be more important in optimizing calf muscle pump function than ankle movement exercises.

  9. Morphoquantitative effects on striated skeletal muscle of Wistar rats (Rattus norvegicus subjected to a diet utilized in young children from rural Mozambique

    Directory of Open Access Journals (Sweden)

    Catarina Tivane Nhamposse

    2016-12-01

    Full Text Available Mozambique is a country of sub-Saharan Africa where about 55% of the population lives below the absolute poverty line with less than one meal a day hardly surviving based on by donations. Food insecurity and precarious nutrition, especially in children, are factors that induce to levels of 44% of chronic malnutrition (CD in infants. The CD is responsible for one third of deaths in children under five years. The aim of this study was to evaluate the morphoquantitative effects in gastrocnemius muscle of Wistar rats fed with a diet utilized by people from rural areas of Mozambique. We used 75 Wistar rats weighing approximately 300 g divided in three groups: nourished or control (N, malnourished (D, and Mozambique or experimental group (M, measured at birth and at weaning. The animals were kept under the same housing conditions, temperature, humidity and light, but with different diets depending on the group: Group N with normal protein diet (20% casein, Group D with hypo-proteic diet (5% casein, and Group M with Mozambique diet. In all groups we evaluated the body mass at birth and weaning, and collected the right gastrocnemius muscle of male pups at weaning for analysis. Serial sections of 10 μm were performed in a cryostat prior to histology techniques of hematoxylin and eosin, picrosirius, NADH-tr and analysis in transmission electron microscope. Statistical evaluation was determined by analysis of variance (ANOVA and Tukey tests. Significant differences were found between groups N, D and M. In group M were observed a great variation of body mass that was approximately similar to group D; Group M also showed the same changes in muscle fiber which exhibited round-shaped contours, and predominance of type III collagen, similarly to malnourished group (D. Ultra-structurally, animals from Mozambique displayed a disorganization of the Z lines of sarcomeres, myofibrils disruption, decreased cross-sectional area and a smaller proportion of

  10. The Time Course of the Loss and Recovery of Contracture Ability in Frog Striated Muscle Following Exposure to Ca-Free Solutions

    Science.gov (United States)

    Milligan, J. V.

    1965-01-01

    Using area under the contracture curve to quantitate contractures, the diffusion coefficient of calcium ions within the frog toe muscle during washout in a calcium-free solution and subsequent recovery after reintroduction of calcium to the bathing solution was calculated to be about 2 x 10-6 cm2/sec. The diffusion coefficient measured during washout was found to be independent of temperature or initial calcium ion concentration. During recovery it was found to decrease if the temperature was lowered. This was likely due to the repolarization occurring after the depolarizing effect of the calcium-free solution. The relation between contracture area and [Ca]o was found to be useful over a wider range than that between maximum tension and [Ca]o. The normalized contracture areas were larger at lower calcium concentrations if the contractures were produced with cold potassium solutions or if NO3 replaced Cl in the bathing solutions. Decreasing the potassium concentration of the contracture solution to 50 mM from 115 mM did not change the relation between [Ca]o and the normalized area. If the K concentration of the bathing solution was increased, the areas were decreased at lower concentrations of Ca. PMID:14324991

  11. Interstitial cells of Cajal in the striated musculature of the mouse esophagus

    DEFF Research Database (Denmark)

    Rumessen, J J; de Kerchove d'Exaerde, A; Mignon, S

    2001-01-01

    Interstitial cells of Cajal (ICC) are important regulatory cells in the smooth muscle coats of the digestive tract. Expression of the Kit receptor tyrosine kinase was used in this study as a marker to study their distribution and development in the striated musculature of the mouse esophagus...... scarce in both muscle layers of the thoracic esophagus, while their number increased steeply toward the cardia in the striated portion of the intraabdominal esophagus. They did not form networks and had no relationship with intrinsic myenteric ganglia and motor end-plates. They were often close to nerve...... but absent in adult ICC-deficient KitW-lacZ/KitWv mice. Interstitial cells of Cajal were identified by electron microscopy by their ultrastructure in the striated muscle of the esophagus and exhibited Xgal labeling, while fibroblasts and muscle cells were unlabeled. Interstitial cells of Cajal are scattered...

  12. Mechanical modeling of skeletal muscle functioning

    NARCIS (Netherlands)

    van der Linden, B.J.J.J.

    1998-01-01

    For movement of body or body segments is combined effort needed of the central nervous system and the muscular-skeletal system. This thesis deals with the mechanical functioning of skeletal muscle. That muscles come in a large variety of geometries, suggest the existence of a relation between muscle

  13. AMPK in skeletal muscle function and metabolism

    DEFF Research Database (Denmark)

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

    2018-01-01

    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...

  14. Disposition of the striated urethral sphincter and its relation to the prostate in human fetuses

    Directory of Open Access Journals (Sweden)

    Luciano A. Favorito

    2007-06-01

    Full Text Available OBJECTIVE: To describe the arrangement of the muscle fibers of the striated urethral sphincter and its relationship with the prostate during the fetal period in humans. MATERIALS AND METHODS: We analyzed 17 prostates from well preserved fresh human fetuses ranging in age from 10 to 31 weeks postconception (WPC. Transversal sections were obtained and stained with Gomori's trichrome and immunolabeled with anti alpha-actin antibody. RESULTS: We found that the urethral striated sphincter (rabdosphincter is located on the periphery of the smooth muscle and there was no merge between striated and smooth muscle fibers in any fetal period. In the prostate apex, the striated sphincter shows a circular arrangement and covers completely the urethra externally, whereas adjacent to verumontanum, it looks like a "horseshoe" and covers only the anterior and lateral surfaces of the urethra. Near the bladder neck, in fetuses younger than 20 WPC, we have found striated muscle fibers only at the anterior surface of the prostate, while in fetuses older than 20 WPC, the striated muscle covers the anterior and lateral surfaces of the prostate. CONCLUSIONS: The urethral sphincter muscle covers the anterior and lateral surfaces of the urethra in all fetuses older than 20 WPC, close to the bladder neck and at the distal prostate. In the region of the prostate apex, the urethral sphincter covers completely the urethra circularly. The knowledge of the normal anatomy of the urethral sphincter in fetuses could be important to understand its alterations in congenital anomalies involving the base of the bladder, the bladder neck and the proximal urethra.

  15. Lack of Glycogenin Causes Glycogen Accumulation and Muscle Function Impairment.

    Science.gov (United States)

    Testoni, Giorgia; Duran, Jordi; García-Rocha, Mar; Vilaplana, Francisco; Serrano, Antonio L; Sebastián, David; López-Soldado, Iliana; Sullivan, Mitchell A; Slebe, Felipe; Vilaseca, Marta; Muñoz-Cánoves, Pura; Guinovart, Joan J

    2017-07-05

    Glycogenin is considered essential for glycogen synthesis, as it acts as a primer for the initiation of the polysaccharide chain. Against expectations, glycogenin-deficient mice (Gyg KO) accumulate high amounts of glycogen in striated muscle. Furthermore, this glycogen contains no covalently bound protein, thereby demonstrating that a protein primer is not strictly necessary for the synthesis of the polysaccharide in vivo. Strikingly, in spite of the higher glycogen content, Gyg KO mice showed lower resting energy expenditure and less resistance than control animals when subjected to endurance exercise. These observations can be attributed to a switch of oxidative myofibers toward glycolytic metabolism. Mice overexpressing glycogen synthase in the muscle showed similar alterations, thus indicating that this switch is caused by the excess of glycogen. These results may explain the muscular defects of GSD XV patients, who lack glycogenin-1 and show high glycogen accumulation in muscle. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. 38 CFR 4.78 - Muscle function.

    Science.gov (United States)

    2010-07-01

    ... visual acuity for the poorer eye (or the affected eye, if disability of only one eye is service-connected... visual acuity for the poorer eye (or the affected eye, if disability of only one eye is service-connected... DISABILITIES Disability Ratings The Organs of Special Sense § 4.78 Muscle function. (a) Examination of muscle...

  17. Vitamin D and muscle function.

    Science.gov (United States)

    Dawson-Hughes, Bess

    2017-10-01

    Muscle weakness is a hallmark of severe vitamin D deficiency, but the effect of milder vitamin D deficiency or insufficiency on muscle mass and performance and risk of falling is uncertain. In this presentation, I review the evidence that vitamin D influences muscle mass and performance, balance, and risk of falling in older adults. Special consideration is given to the impact of both the starting 25-hydroxyvitamin D [25(OH)D] level and the dose administered on the clinical response to supplemental vitamin D in older men and women. Based on available evidence, older adults with serum 25(OH)D levels vitamin D dose range of 800-1000 IU per day has been effective in many studies; lower doses have generally been ineffective and several doses above this range have increased the risk of falls. In conclusion, older adults with serum 25(OH)D levels vitamin D. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Quantitative comparison of striated toolmarks.

    Science.gov (United States)

    Baiker, Martin; Keereweer, Isaac; Pieterman, René; Vermeij, Erwin; van der Weerd, Jaap; Zoon, Peter

    2014-09-01

    A comparison of striated toolmarks by human examiners is dependent on the experience of the expert and includes a subjective judgment within the process. In this article an automated method is presented for objective comparison of striated marks of screwdrivers. The combination of multi-scale registration (alignment) of toolmarks, that accounts for shift and scaling, with global cross correlation as objective toolmark similarity metric renders the approach robust with respect to large differences in angle of attack and moderate toolmark compression. In addition, a strategy to distinguish between relevant and non-relevant spatial frequency ranges (geometric details) is presented. The performance of the method is evaluated using 3D topography scans of experimental toolmarks of 50 unused screwdrivers. Known match and known non-match similarity distributions are estimated including a large range of angles of attack (15, 30, 45, 60 and 75°) for the known matches. It is demonstrated that the system has high discriminatory power, even if the toolmarks are made at a difference in angle of attack of larger than 15°. The probability distributions are subsequently employed to determine likelihood ratios. A comparison of the results of the automated method with the outcome of a toolmark comparison experiment involving three experienced toolmark examiners reveals, that the automated system is more powerful in correctly supporting the hypothesis of common origin for toolmarks with a large difference in angle of attack (30°). In return, the rate of toolmark comparisons that yield incorrect support for the hypothesis of common origin is higher for the automated system. In addition, a comparison between estimating known match and known non-match distributions using 2D and 3D data is presented and it is shown that for toolmarks of unused screwdrivers, relying on 3D is slightly better than relying on 2D data. Finally, a comparison between estimating known match and known non

  19. Testosterone Replacement, Muscle Strength, and Physical Function

    Directory of Open Access Journals (Sweden)

    You-Seon Nam

    2018-05-01

    Full Text Available Muscle strength and physical function decrease in older men, as do testosterone levels. Nonetheless, the effects of testosterone replacement therapy on muscle strength and physical function remain inconclusive and equivocal. We conducted a rapid systematic review, the results of which showed that testosterone replacement does not affect muscle strength (measured by hand grip strength and leg muscle strength, although it may increase physical function (measured by the 6-minute walk test, Physical Activity Scale for the Elderly score, and other physical performance tests. However, most of the studies were conducted in the United States or Europe and did not include participants from Asian or other ethnic backgrounds; therefore, further studies are needed to evaluate the effects of testosterone replacement in a broader population.

  20. Respiratory muscle function in interstitial lung disease.

    Science.gov (United States)

    Walterspacher, Stephan; Schlager, Daniel; Walker, David J; Müller-Quernheim, Joachim; Windisch, Wolfram; Kabitz, Hans-Joachim

    2013-07-01

    Interstitial lung diseases limit daily activities, impair quality of life and result in (exertional) dyspnoea. This has mainly been attributed to a decline in lung function and impaired gas exchange. However, the contribution of respiratory muscle dysfunction to these limitations remains to be conclusively investigated. Interstitial lung disease patients and matched controls performed body plethysmography, a standardised 6-min walk test, volitional tests (respiratory drive (P0.1), global maximal inspiratory mouth occlusion pressure (PImax), sniff nasal pressure (SnPna) and inspiratory muscle load) and nonvolitional tests on respiratory muscle function and strength (twitch mouth and transdiaphragmatic pressure during bilateral magnetic phrenic nerve stimulation (TwPmo and TwPdi)). 25 patients and 24 controls were included in the study. PImax and SnPna remained unaltered (both p>0.05), whereas P0.1 and the load on the inspiratory muscles were higher (both prespiratory muscle strength remains preserved. Central respiratory drive and the load imposed on the inspiratory muscles are increased. Whether impaired respiratory muscle function impacts morbidity and mortality in interstitial lung disease patients needs to be investigated in future studies.

  1. Interstitial cells of Cajal in the striated musculature of the mouse esophagus

    DEFF Research Database (Denmark)

    Rumessen, J J; de Kerchove d'Exaerde, A; Mignon, S

    2001-01-01

    Interstitial cells of Cajal (ICC) are important regulatory cells in the smooth muscle coats of the digestive tract. Expression of the Kit receptor tyrosine kinase was used in this study as a marker to study their distribution and development in the striated musculature of the mouse esophagus. Sec...

  2. Muscle Function in Osteogenesis Imperfecta Type IV.

    Science.gov (United States)

    Veilleux, Louis-Nicolas; Darsaklis, Vasiliki B; Montpetit, Kathleen; Glorieux, Francis H; Rauch, Frank

    2017-10-01

    Results of previous studies suggest that children and adolescents with osteogenesis imperfecta (OI) type IV have muscle force deficits. However, muscle function remains to be objectively quantified in this population. This study aimed to assess upper and lower extremity muscle function in patients with OI type IV. It was carried out in the outpatient department of a pediatric orthopedic hospital; 27 individuals with OI type IV (7-21 years; 13 males), 27 age- and sex-matched individuals with OI type I, and 27 age- and sex-matched controls. Upper extremity muscle force was assessed with hydraulic hand dynamometry, and lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by mechanography through five tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Upper-limb grip force was normal for patients with OI type IV when compared to height and sex reference data (average z-score = 0.17 ± 1.30; P = 0.88). Compared to age- and sex-matched controls, patients with OI type IV had approximately 30% lower-limb peak force and 50% peak power deficits (P values <0.05). At the lower-limb level, they had a 50% lower peak power than age- and sex-matched patients with OI type I (P < 0.05). Patients with OI type IV have normal upper-limb muscle force but a muscle function deficit at the lower-limb level. These results suggest that lower-limb muscle weakness may contribute to functional deficits in these individuals.

  3. The effect of transient, moderate dietary phosphorus deprivation on phosphorus metabolism, muscle content of different phosphorus-containing compounds, and muscle function in dairy cows.

    Science.gov (United States)

    Grünberg, W; Scherpenisse, P; Dobbelaar, P; Idink, M J; Wijnberg, I D

    2015-08-01

    decline in muscle tissue P content. Electromyographic examination revealed increased occurrence of pathological spontaneous activity in striated muscles after 2 wk of dietary P depletion in several cows, which could be suggestive of neuromuscular membrane instability. No effect on heart muscle activity was identified electrocardiographically. These results suggest that counter-regulatory mechanisms were sufficient to maintain normal muscle tissue P content during transient and moderate P deprivation. Muscle function was not grossly affected, although the increased occurrence of pathological spontaneous activity suggests that subclinical neuropathy or myopathy, or both, may have occurred with ongoing P deprivation. The results presented here indicate that plasma [Pi] is unsuitable for assessing muscle tissue P content in cattle. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Abdominal muscle function and incisional hernia

    DEFF Research Database (Denmark)

    Jensen, K K; Kjaer, M; Jorgensen, L N

    2014-01-01

    PURPOSE: Although ventral incisional hernia (VIH) repair in patients is often evaluated in terms of hernia recurrence rate and health-related quality of life, there is no clear consensus regarding optimal operative treatment based on these parameters. It was proposed that health-related quality...... of life depends largely on abdominal muscle function (AMF), and the present review thus evaluates to what extent AMF is influenced by VIH and surgical repair. METHODS: The PubMed and EMBASE databases were searched for articles following a systematic strategy for inclusion. RESULTS: A total of seven...... studies described AMF in relation to VIH. Five studies examined AMF using objective isokinetic dynamometers to determine muscle strength, and two studies examined AMF by clinical examination-based muscle tests. CONCLUSION: Both equipment-related and functional muscle tests exist for use in patients...

  5. Independent specialisation of myosin II paralogues in muscle vs. non-muscle functions during early animal evolution: a ctenophore perspective.

    Science.gov (United States)

    Dayraud, Cyrielle; Alié, Alexandre; Jager, Muriel; Chang, Patrick; Le Guyader, Hervé; Manuel, Michaël; Quéinnec, Eric

    2012-07-02

    Myosin II (or Myosin Heavy Chain II, MHCII) is a family of molecular motors involved in the contractile activity of animal muscle cells but also in various other cellular processes in non-muscle cells. Previous phylogenetic analyses of bilaterian MHCII genes identified two main clades associated respectively with smooth/non-muscle cells (MHCIIa) and striated muscle cells (MHCIIb). Muscle cells are generally thought to have originated only once in ancient animal history, and decisive insights about their early evolution are expected to come from expression studies of Myosin II genes in the two non-bilaterian phyla that possess muscles, the Cnidaria and Ctenophora. We have uncovered three MHCII paralogues in the ctenophore species Pleurobrachia pileus. Phylogenetic analyses indicate that the MHCIIa / MHCIIb duplication is more ancient than the divergence between extant metazoan lineages. The ctenophore MHCIIa gene (PpiMHCIIa) has an expression pattern akin to that of "stem cell markers" (Piwi, Vasa…) and is expressed in proliferating cells. We identified two MHCIIb genes that originated from a ctenophore-specific duplication. PpiMHCIIb1 represents the exclusively muscular form of myosin II in ctenophore, while PpiMHCIIb2 is expressed in non-muscle cells of various types. In parallel, our phalloidin staining and TEM observations highlight the structural complexity of ctenophore musculature and emphasize the experimental interest of the ctenophore tentacle root, in which myogenesis is spatially ordered and strikingly similar to striated muscle formation in vertebrates. MHCIIa expression in putative stem cells/proliferating cells probably represents an ancestral trait, while specific involvement of some MHCIIa genes in smooth muscle fibres is a uniquely derived feature of the vertebrates. That one ctenophore MHCIIb paralogue (PpiMHCIIb2) has retained MHCIIa-like expression features furthermore suggests that muscular expression of the other paralogue, PpiMHCIIb1, was

  6. Independent specialisation of myosin II paralogues in muscle vs. non-muscle functions during early animal evolution: a ctenophore perspective

    Science.gov (United States)

    2012-01-01

    Background Myosin II (or Myosin Heavy Chain II, MHCII) is a family of molecular motors involved in the contractile activity of animal muscle cells but also in various other cellular processes in non-muscle cells. Previous phylogenetic analyses of bilaterian MHCII genes identified two main clades associated respectively with smooth/non-muscle cells (MHCIIa) and striated muscle cells (MHCIIb). Muscle cells are generally thought to have originated only once in ancient animal history, and decisive insights about their early evolution are expected to come from expression studies of Myosin II genes in the two non-bilaterian phyla that possess muscles, the Cnidaria and Ctenophora. Results We have uncovered three MHCII paralogues in the ctenophore species Pleurobrachia pileus. Phylogenetic analyses indicate that the MHCIIa / MHCIIb duplication is more ancient than the divergence between extant metazoan lineages. The ctenophore MHCIIa gene (PpiMHCIIa) has an expression pattern akin to that of "stem cell markers" (Piwi, Vasa…) and is expressed in proliferating cells. We identified two MHCIIb genes that originated from a ctenophore-specific duplication. PpiMHCIIb1 represents the exclusively muscular form of myosin II in ctenophore, while PpiMHCIIb2 is expressed in non-muscle cells of various types. In parallel, our phalloidin staining and TEM observations highlight the structural complexity of ctenophore musculature and emphasize the experimental interest of the ctenophore tentacle root, in which myogenesis is spatially ordered and strikingly similar to striated muscle formation in vertebrates. Conclusion MHCIIa expression in putative stem cells/proliferating cells probably represents an ancestral trait, while specific involvement of some MHCIIa genes in smooth muscle fibres is a uniquely derived feature of the vertebrates. That one ctenophore MHCIIb paralogue (PpiMHCIIb2) has retained MHCIIa-like expression features furthermore suggests that muscular expression of the

  7. Independent specialisation of myosin II paralogues in muscle vs. non-muscle functions during early animal evolution: a ctenophore perspective

    Directory of Open Access Journals (Sweden)

    Dayraud Cyrielle

    2012-07-01

    Full Text Available Abstract Background Myosin II (or Myosin Heavy Chain II, MHCII is a family of molecular motors involved in the contractile activity of animal muscle cells but also in various other cellular processes in non-muscle cells. Previous phylogenetic analyses of bilaterian MHCII genes identified two main clades associated respectively with smooth/non-muscle cells (MHCIIa and striated muscle cells (MHCIIb. Muscle cells are generally thought to have originated only once in ancient animal history, and decisive insights about their early evolution are expected to come from expression studies of Myosin II genes in the two non-bilaterian phyla that possess muscles, the Cnidaria and Ctenophora. Results We have uncovered three MHCII paralogues in the ctenophore species Pleurobrachia pileus. Phylogenetic analyses indicate that the MHCIIa / MHCIIb duplication is more ancient than the divergence between extant metazoan lineages. The ctenophore MHCIIa gene (PpiMHCIIa has an expression pattern akin to that of "stem cell markers" (Piwi, Vasa… and is expressed in proliferating cells. We identified two MHCIIb genes that originated from a ctenophore-specific duplication. PpiMHCIIb1 represents the exclusively muscular form of myosin II in ctenophore, while PpiMHCIIb2 is expressed in non-muscle cells of various types. In parallel, our phalloidin staining and TEM observations highlight the structural complexity of ctenophore musculature and emphasize the experimental interest of the ctenophore tentacle root, in which myogenesis is spatially ordered and strikingly similar to striated muscle formation in vertebrates. Conclusion MHCIIa expression in putative stem cells/proliferating cells probably represents an ancestral trait, while specific involvement of some MHCIIa genes in smooth muscle fibres is a uniquely derived feature of the vertebrates. That one ctenophore MHCIIb paralogue (PpiMHCIIb2 has retained MHCIIa-like expression features furthermore suggests that muscular

  8. The human cardiac and skeletal muscle proteomes defined by transcriptomics and antibody-based profiling

    DEFF Research Database (Denmark)

    Lindskog, Cecilia; Linne, Jerker; Fagerberg, Linn

    2015-01-01

    Background: To understand cardiac and skeletal muscle function, it is important to define and explore their molecular constituents and also to identify similarities and differences in the gene expression in these two different striated muscle tissues. Here, we have investigated the genes and prot......Background: To understand cardiac and skeletal muscle function, it is important to define and explore their molecular constituents and also to identify similarities and differences in the gene expression in these two different striated muscle tissues. Here, we have investigated the genes...... genes are well in line with the physiological functions of cardiac and skeletal muscle, such as contraction, ion transport, regulation of membrane potential and actomyosin structure organization. A large fraction of the transcripts in both cardiac and skeletal muscle correspond to mitochondrial proteins...

  9. Bion 11 Spaceflight Project: Effect of Weightlessness on Single Muscle Fiber Function in Rhesus Monkeys

    Science.gov (United States)

    Fitts, Robert H.; Romatowski, Janell G.; Widrick, Jeffrey J.; DeLaCruz, Lourdes

    1999-01-01

    Although it is well known that microgravity induces considerable limb muscle atrophy, little is known about how weightlessness alters cell function. In this study, we investigated how weightlessness altered the functional properties of single fast and slow striated muscle fibers. Physiological studies were carried out to test the hypothesis that microgravity causes fiber atrophy, a decreased peak force (Newtons), tension (Newtons/cross-sectional area) and power, an elevated peak rate of tension development (dp/dt), and an increased maximal shortening velocity (V(sub o)) in the slow type I fiber, while changes in the fast-twitch fiber are restricted to atrophy and a reduced peak force. For each fiber, we determined the peak force (P(sub o)), V(sub o), dp/dt, the force-velocity relationship, peak power, the power-force relationship, the force-pCa relationship, and fiber stiffness. Biochemical studies were carried out to assess the effects of weightlessness on the enzyme and substrate profile of the fast- and slow-twitch fibers. We predicted that microgravity would increase resting muscle glycogen and glycolytic metabolism in the slow fiber type, while the fast-twitch fiber enzyme profile would be unaltered. The increased muscle glycogen would in part result from an elevated hexokinase and glycogen synthase. The enzymes selected for study represent markers for mitochondrial function (citrate synthase and 0-hydroxyacyl-CoA dehydrogenase), glycolysis (Phosphofructokinase and lactate dehydrogenase), and fatty acid transport (Carnitine acetyl transferase). The substrates analyzed will include glycogen, lactate, adenosine triphosphate, and phosphocreatine.

  10. Redox characterization of functioning skeletal muscle

    Directory of Open Access Journals (Sweden)

    Li eZuo

    2015-11-01

    Full Text Available Skeletal muscle physiology is influenced by the presence of chemically reactive molecules such as reactive oxygen species (ROS. These molecules regulate multiple redox-sensitive signaling pathways that play a critical role in cellular processes including gene expression and protein modification. While ROS have gained much attention for their harmful effects in muscle fatigue and dysfunction, research has also shown ROS to facilitate muscle adaptation after stressors such as physical exercise. This manuscript aims to provide a comprehensive review of the current understanding of redox signaling in skeletal muscle. ROS-induced oxidative stress and its role in the aging process are discussed. Mitochondria have been shown to generate large amounts of ROS during muscular contractions, and thus are susceptible to oxidative stress. ROS can modify proteins located in the mitochondrial membrane leading to cell death and osmotic swelling. ROS also contribute to the necrosis and inflammation of muscle fibers that is associated with muscular diseases including Duchenne muscular dystrophy (DMD. It is imperative that future research continues to investigate the exact role of ROS in normal skeletal muscle function as well as muscular dysfunction and disease.

  11. Mechanomyogram for muscle function assessment: a review.

    Directory of Open Access Journals (Sweden)

    Md Anamul Islam

    Full Text Available Mechanomyography (MMG has been extensively applied in clinical and experimental practice to examine muscle characteristics including muscle function (MF, prosthesis and/or switch control, signal processing, physiological exercise, and medical rehabilitation. Despite several existing MMG studies of MF, there has not yet been a review of these. This study aimed to determine the current status on the use of MMG in measuring the conditions of MFs.Five electronic databases were extensively searched for potentially eligible studies published between 2003 and 2012. Two authors independently assessed selected articles using an MS-Word based form created for this review. Several domains (name of muscle, study type, sensor type, subject's types, muscle contraction, measured parameters, frequency range, hardware and software, signal processing and statistical analysis, results, applications, authors' conclusions and recommendations for future work were extracted for further analysis. From a total of 2184 citations 119 were selected for full-text evaluation and 36 studies of MFs were identified. The systematic results find sufficient evidence that MMG may be used for assessing muscle fatigue, strength, and balance. This review also provides reason to believe that MMG may be used to examine muscle actions during movements and for monitoring muscle activities under various types of exercise paradigms.Overall judging from the increasing number of articles in recent years, this review reports sufficient evidence that MMG is increasingly being used in different aspects of MF. Thus, MMG may be applied as a useful tool to examine diverse conditions of muscle activity. However, the existing studies which examined MMG for MFs were confined to a small sample size of healthy population. Therefore, future work is needed to investigate MMG, in examining MFs between a sufficient number of healthy subjects and neuromuscular patients.

  12. The pelvic floor muscles: muscle thickness in healthy and urinary-incontinent women measured by perineal ultrasonography with reference to the effect of pelvic floor training. Estrogen receptor studies

    DEFF Research Database (Denmark)

    Bernstein, Inge Thomsen

    1997-01-01

    depends on the structural components in the urethral wall, the position of the bladder neck and proximal urethra, the periurethral striated muscles, and the pelvic floor muscles. By means of pudendal blockade and simultaneous recordings of pressure and cross-sectional area in the urethra, it has been...... demonstrated that the striated periurethral muscles and the pelvic floor muscles are of paramount importance for the closure function. This emphasizes the importance of well-functioning pelvic floor muscles to obtain continence, and probably explains the rationale for the effect of pelvic floor training...... in treating urinary incontinence. This study presents a review of the literature on female urinary incontinence, continence mechanisms, pelvic floor muscles, and pelvic floor training. Furthermore, a review of the literature on estrogen receptors in the pelvic floor muscles is given. Perineal ultrasonography...

  13. Muscle mass, muscle strength, and muscle fat infiltration as predictors of incident mobility limitations in well-functioning older persons

    NARCIS (Netherlands)

    Visser, Marjolein; Goodpaster, Bret H; Kritchevsky, Stephen B; Newman, Anne B; Nevitt, Michael; Rubin, Susan M; Simonsick, Eleanor M; Harris, Tamara B

    BACKGROUND: Lower muscle mass has been correlated with poor physical function; however, no studies have examined this relationship prospectively. This study aims to investigate whether low muscle mass, low muscle strength, and greater fat infiltration into the muscle predict incident mobility

  14. Relationship between neck muscles functions and hand muscles strenght in musicians

    OpenAIRE

    Vaina, Mindaugas

    2016-01-01

    Relationship Between Neck Muscles Functions and Hand Muscles Strenght in Musicians The aim of research work: to determine the relationship between musicians hand muscle strength, fatigue and neck strength, endurance and movement amplitude. Tasks of work: 1. To evaluate and compare the musicians playing with string and wind instruments neck muscle strength, endurance, range of motion, hand muscle strength and fatigue between the groups as well as commonly used standards. 2. To determine the re...

  15. Aspects of smooth muscle function in molluscan catch muscle.

    Science.gov (United States)

    Twarog, B M

    1976-10-01

    1) Catch in Mytilus ABRM may be a specialization of a mechanism common to all muscles that gives rise to stretch resistance in the resting state. Catch appears to be due to actin myosin interaction. Since this interaction is regulated by nerves, it provides a convenient model for studying resting stretch resistance. 2) Studies of the structure of Mytilus ABRM revela two types of intercellular connections: a) direct connections between muscle fibers [these nexal (gap) junctions interconnect the muscle cells electrically]; b) muscle fiber-collagen-muscle fiber connections [these provide mechanical connections between muscle cells via collagen fibers]. The structure of Mytilus ABRM supports speculation that smooth muscle filaments are organized into contractile units. 3) A rise in cAMP levels occurs in response to the relaxing transmitter, serotonin. It is not certain whether the cAMP system directly controls the ability of the contractile proteins to interact or whether it regulates intracellular levels of Ca2+. 4) Calcium ions in activation are derived from two sources: an internal source, probably the sarcoplasmic reticulum, and an external source, across the muscle membrane. 5) The nature of catch remains in question, although most evidence favors the linkage hypothesis.

  16. Functional impact of sarcopenia in respiratory muscles.

    Science.gov (United States)

    Elliott, Jonathan E; Greising, Sarah M; Mantilla, Carlos B; Sieck, Gary C

    2016-06-01

    The risk for respiratory complications and infections is substantially increased in old age, which may be due, in part, to sarcopenia (aging-related weakness and atrophy) of the diaphragm muscle (DIAm), reducing its force generating capacity and impairing the ability to perform expulsive non-ventilatory motor behaviors critical for airway clearance. The aging-related reduction in DIAm force generating capacity is due to selective atrophy of higher force generating type IIx and/or IIb muscle fibers, whereas lower force generating type I and IIa muscle fiber sizes are preserved. Fiber type specific DIAm atrophy is also seen following unilateral phrenic nerve denervation and in other neurodegenerative disorders. Accordingly, the effect of aging on DIAm function resembles that of neurodegeneration and suggests possible common mechanisms, such as the involvement of several neurotrophic factors in mediating DIAm sarcopenia. This review will focus on changes in two neurotrophic signaling pathways that represent potential mechanisms underlying the aging-related fiber type specific DIAm atrophy. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Unconventional Functions of Muscles in Planarian Regeneration.

    Science.gov (United States)

    Cutie, Stephen; Hoang, Alison T; Payumo, Alexander Y; Huang, Guo N

    2017-12-18

    Muscles are traditionally considered in the context of force generation. Scimone et al. (2017), reporting in Nature, now examine muscles in a developmental setting and find unexpected roles for distinct planarian muscle fibers. The authors show that muscles provide patterning signals to promote regeneration and guide tissue growth after injury. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Evaluation of muscle function of the extensor digitorum longus muscle ex vivo and tibialis anterior muscle in situ in mice.

    Science.gov (United States)

    Hakim, Chady H; Wasala, Nalinda B; Duan, Dongsheng

    2013-02-09

    Body movements are mainly provided by mechanical function of skeletal muscle. Skeletal muscle is composed of numerous bundles of myofibers that are sheathed by intramuscular connective tissues. Each myofiber contains many myofibrils that run longitudinally along the length of the myofiber. Myofibrils are the contractile apparatus of muscle and they are composed of repeated contractile units known as sarcomeres. A sarcomere unit contains actin and myosin filaments that are spaced by the Z discs and titin protein. Mechanical function of skeletal muscle is defined by the contractile and passive properties of muscle. The contractile properties are used to characterize the amount of force generated during muscle contraction, time of force generation and time of muscle relaxation. Any factor that affects muscle contraction (such as interaction between actin and myosin filaments, homeostasis of calcium, ATP/ADP ratio, etc.) influences the contractile properties. The passive properties refer to the elastic and viscous properties (stiffness and viscosity) of the muscle in the absence of contraction. These properties are determined by the extracellular and the intracellular structural components (such as titin) and connective tissues (mainly collagen) (1-2). The contractile and passive properties are two inseparable aspects of muscle function. For example, elbow flexion is accomplished by contraction of muscles in the anterior compartment of the upper arm and passive stretch of muscles in the posterior compartment of the upper arm. To truly understand muscle function, both contractile and passive properties should be studied. The contractile and/or passive mechanical properties of muscle are often compromised in muscle diseases. A good example is Duchenne muscular dystrophy (DMD), a severe muscle wasting disease caused by dystrophin deficiency (3). Dystrophin is a cytoskeletal protein that stabilizes the muscle cell membrane (sarcolemma) during muscle contraction (4). In the

  20. Muscle MRI Findings in Childhood/Adult Onset Pompe Disease Correlate with Muscle Function.

    Directory of Open Access Journals (Sweden)

    Sebastián Figueroa-Bonaparte

    Full Text Available Enzyme replacement therapy has shown to be effective for childhood/adult onset Pompe disease (AOPD. The discovery of biomarkers useful for monitoring disease progression is one of the priority research topics in Pompe disease. Muscle MRI could be one possible test but the correlation between muscle MRI and muscle strength and function has been only partially addressed so far.We studied 34 AOPD patients using functional scales (Manual Research Council scale, hand held myometry, 6 minutes walking test, timed to up and go test, time to climb up and down 4 steps, time to walk 10 meters and Motor Function Measure 20 Scale, respiratory tests (Forced Vital Capacity seated and lying, Maximun Inspiratory Pressure and Maximum Expiratory Pressure, daily live activities scales (Activlim and quality of life scales (Short Form-36 and Individualized Neuromuscular Quality of Life questionnaire. We performed a whole body muscle MRI using T1w and 3-point Dixon imaging centered on thighs and lower trunk region.T1w whole body muscle MRI showed a homogeneous pattern of muscle involvement that could also be found in pre-symptomatic individuals. We found a strong correlation between muscle strength, muscle functional scales and the degree of muscle fatty replacement in muscle MRI analyzed using T1w and 3-point Dixon imaging studies. Moreover, muscle MRI detected mild degree of fatty replacement in paraspinal muscles in pre-symptomatic patients.Based on our findings, we consider that muscle MRI correlates with muscle function in patients with AOPD and could be useful for diagnosis and follow-up in pre-symptomatic and symptomatic patients under treatment.Muscle MRI correlates with muscle function in patients with AOPD and could be useful to follow-up patients in daily clinic.

  1. Respiratory and lower limb muscle function in interstitial lung disease.

    Science.gov (United States)

    Panagiotou, Marios; Polychronopoulos, Vlasis; Strange, Charlie

    2016-05-01

    Growing evidence suggests that respiratory and limb muscle function may be impaired in patients with interstitial lung disease (ILD). Importantly, muscle dysfunction could promote dyspnoea, fatigue and functional limitation all of which are cardinal features of ILD. This article examines the risk factors for skeletal muscle dysfunction in ILD, reviews the current evidence on overall respiratory and limb muscle function and focuses on the occurrence and implications of skeletal muscle dysfunction in ILD. Research limitations and pathways to address the current knowledge gaps are highlighted. © The Author(s) 2016.

  2. Individual muscle control using an exoskeleton robot for muscle function testing.

    Science.gov (United States)

    Ueda, Jun; Ming, Ding; Krishnamoorthy, Vijaya; Shinohara, Minoru; Ogasawara, Tsukasa

    2010-08-01

    Healthy individuals modulate muscle activation patterns according to their intended movement and external environment. Persons with neurological disorders (e.g., stroke and spinal cord injury), however, have problems in movement control due primarily to their inability to modulate their muscle activation pattern in an appropriate manner. A functionality test at the level of individual muscles that investigates the activity of a muscle of interest on various motor tasks may enable muscle-level force grading. To date there is no extant work that focuses on the application of exoskeleton robots to induce specific muscle activation in a systematic manner. This paper proposes a new method, named "individual muscle-force control" using a wearable robot (an exoskeleton robot, or a power-assisting device) to obtain a wider variety of muscle activity data than standard motor tasks, e.g., pushing a handle by hand. A computational algorithm systematically computes control commands to a wearable robot so that a desired muscle activation pattern for target muscle forces is induced. It also computes an adequate amount and direction of a force that a subject needs to exert against a handle by his/her hand. This individual muscle control method enables users (e.g., therapists) to efficiently conduct neuromuscular function tests on target muscles by arbitrarily inducing muscle activation patterns. This paper presents a basic concept, mathematical formulation, and solution of the individual muscle-force control and its implementation to a muscle control system with an exoskeleton-type robot for upper extremity. Simulation and experimental results in healthy individuals justify the use of an exoskeleton robot for future muscle function testing in terms of the variety of muscle activity data.

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

    Science.gov (United States)

    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.

  4. Peripheral Muscle Strength Indicates Respiratory Function Testing in Renal Recipients.

    Science.gov (United States)

    Ulubay, Gaye; Uyanik, Saliha; Er Dedekarginoglu, Balam; Serifoglu, Irem; Kupeli, Elif; Savas Bozbas, Serife; Sezer, Siren; Haberal, Mehmet

    2017-02-01

    Muscle wasting occurs in renal recipients due to decreased physical performance, and decreased respiratory muscle strength may occur due to changes in structure and function. Data are scarce regarding the roles of sarcopenia and nutritional status on respiratory muscle function in these patients. Here, we evaluated interactions among peripheral muscle strength, sarcopenia, nutritional parameters, and respiratory muscle function in renal transplant recipients. Ninety-nine patients were prospectively enrolled between September and April 2016 at Baskent University. Forced vital capacity values (via pulmonary function tests), respiratory muscle strength (via maximal static inspiratory and expiratory pressures), and peripheral muscle strength (via hand grip strength test) were recorded. Nutritional parameters, fat weight, arm circumference, waist circumference, and C-reactive protein levels were also recorded. Of 99 patients, 68 were renal transplant recipients (43 men, mean age: 39.09 ± 10.70 y) and 31 were healthy participants (14 men, mean age: 34.94 ± 10.95 y). Forced vital capacity (P .05). No statistically significant relation was observed between biochemical parameters and maximal inspiratory and expiratory pressures (P ? .05). Respiratory function and peripheral muscle strength were significantly related in renal transplant recipients, with significantly lower peripheral muscle strength suggesting the presence of inadequate respiratory function. Peripheral and respiratory muscle training and nutritional replacement strategies could help to improve postoperative respiratory function.

  5. The length-force behavior and operating length range of squid muscle vary as a function of position in the mantle wall.

    Science.gov (United States)

    Thompson, Joseph T; Shelton, Ryan M; Kier, William M

    2014-06-15

    force. Sonomicrometry experiments revealed that the CMP circular muscle fibers operated in vivo primarily along the ascending limb of the length-tension curve. The CMP fibers functioned routinely over muscle lengths at which force output ranged from only 85% to 40% of P₀, and during escape jets from 100% to 30% of P₀. Our work shows that the functional diversity of obliquely striated muscles is much greater than previously recognized. © 2014. Published by The Company of Biologists Ltd.

  6. Bones, Muscles, and Joints: The Musculoskeletal System

    Science.gov (United States)

    ... Skeletal muscles are called striated (pronounced: STRY-ay-ted) because they are made up of fibers that ... blood through your body. When we smile and talk, muscles are helping us communicate, and when we ...

  7. Atrophy and hypertrophy of skeletal muscles: structural and functional aspects.

    Science.gov (United States)

    Boonyarom, O; Inui, K

    2006-10-01

    This review summarizes current information on structural and functional changes that occur during muscle atrophy and hypertrophy. Most published studies consider an increase in total mass of a muscle as hypertrophy, whereas a decrease in total mass of a muscle is referred to as atrophy. In hypertrophy, the rate of synthesis is much higher than the rate of degradation of muscle contractile proteins, leading to an increase in the size or volume of an organ due to enlargement of existing cells. When a muscle remains in disuse for a long period, the rate of degradation of contractile proteins becomes greater than the rate of replacement, resulting in muscle atrophy. This defect may occur as a result of lack of nutrition, loss of nerve supply, micro-gravity, ageing, systemic disease, prolonged immobilization or disuse. An understanding of the specific modifications that occur during muscle atrophy and hypertrophy may facilitate the development of novel techniques, as well as new therapies for affected muscles.

  8. Muscle satellite cells are functionally impaired in myasthenia gravis: consequences on muscle regeneration.

    Science.gov (United States)

    Attia, Mohamed; Maurer, Marie; Robinet, Marieke; Le Grand, Fabien; Fadel, Elie; Le Panse, Rozen; Butler-Browne, Gillian; Berrih-Aknin, Sonia

    2017-12-01

    Myasthenia gravis (MG) is a neuromuscular disease caused in most cases by anti-acetyl-choline receptor (AChR) autoantibodies that impair neuromuscular signal transmission and affect skeletal muscle homeostasis. Myogenesis is carried out by muscle stem cells called satellite cells (SCs). However, myogenesis in MG had never been explored. The aim of this study was to characterise the functional properties of myasthenic SCs as well as their abilities in muscle regeneration. SCs were isolated from muscle biopsies of MG patients and age-matched controls. We first showed that the number of Pax7+ SCs was increased in muscle sections from MG and its experimental autoimmune myasthenia gravis (EAMG) mouse model. Myoblasts isolated from MG muscles proliferate and differentiate more actively than myoblasts from control muscles. MyoD and MyoG were expressed at a higher level in MG myoblasts as well as in MG muscle biopsies compared to controls. We found that treatment of control myoblasts with MG sera or monoclonal anti-AChR antibodies increased the differentiation and MyoG mRNA expression compared to control sera. To investigate the functional ability of SCs from MG muscle to regenerate, we induced muscle regeneration using acute cardiotoxin injury in the EAMG mouse model. We observed a delay in maturation evidenced by a decrease in fibre size and MyoG mRNA expression as well as an increase in fibre number and embryonic myosin heavy-chain mRNA expression. These findings demonstrate for the first time the altered function of SCs from MG compared to control muscles. These alterations could be due to the anti-AChR antibodies via the modulation of myogenic markers resulting in muscle regeneration impairment. In conclusion, the autoimmune attack in MG appears to have unsuspected pathogenic effects on SCs and muscle regeneration, with potential consequences on myogenic signalling pathways, and subsequently on clinical outcome, especially in the case of muscle stress.

  9. The adaptative response of jaw muscles to varying functional demands

    NARCIS (Netherlands)

    Grünheid, T.; Langenbach, G.E.J.; Korfage, J.A.M.; Zentner, A.; van Eijden, T.M.G.J.

    2009-01-01

    Jaw muscles are versatile entities that are able to adapt their anatomical characteristics, such as size, cross-sectional area, and fibre properties, to altered functional demands. The dynamic nature of muscle fibres allows them to change their phenotype to optimize the required contractile function

  10. Assessment of isokinetic muscle function in Korea male volleyball athletes.

    Science.gov (United States)

    Kim, Chang-Gyun; Jeoung, Bog Ja

    2016-10-01

    Volleyball players performed numerous repetitions of spike actions, which uses and requires strong and explosive force, and control of the muscles of the shoulder, lower back, and legs. Muscle imbalance is one of the main causes of sport injuries. The purpose of this study was to assess isokinetic muscle functions in male volleyball players. We thus aim to accurately evaluate their muscle functions, and identify the best training strategy to achieve optimal muscle strength balance in future training programs. The participants in this study consisted of 14 male volleyball players. Muscle strength was measured using the isokinetic dynamometer. Muscle strength was evaluated in terms of peak torque and average power, calculated from five repeated measurements at an angular speed of 60°/sec. Three players who were left attackers showed shoulder imbalance, four players showed trunk joint imbalance, nine players had knee joint of extension/flexion imbalance and four players showed left/right imbalance. The results showed that the number of volleyball players with differences between the strength of the bilateral knee muscles, and between the strength of the hamstrings and quadriceps muscles was higher than the number of players with differences between the strength of the shoulder internal and external rotation muscles, and higher than the number of players with differences between the strength of the lower back extension and flexion muscles.

  11. Distinctive serum miRNA profile in mouse models of striated muscular pathologies.

    Directory of Open Access Journals (Sweden)

    Nicolas Vignier

    Full Text Available Biomarkers are critically important for disease diagnosis and monitoring. In particular, close monitoring of disease evolution is eminently required for the evaluation of therapeutic treatments. Classical monitoring methods in muscular dystrophies are largely based on histological and molecular analyses of muscle biopsies. Such biopsies are invasive and therefore difficult to obtain. The serum protein creatine kinase is a useful biomarker, which is however not specific for a given pathology and correlates poorly with the severity or course of the muscular pathology. The aim of the present study was the systematic evaluation of serum microRNAs (miRNAs as biomarkers in striated muscle pathologies. Mouse models for five striated muscle pathologies were investigated: Duchenne muscular dystrophy (DMD, limb-girdle muscular dystrophy type 2D (LGMD2D, limb-girdle muscular dystrophy type 2C (LGMD2C, Emery-Dreifuss muscular dystrophy (EDMD and hypertrophic cardiomyopathy (HCM. Two-step RT-qPCR methodology was elaborated, using two different RT-qPCR miRNA quantification technologies. We identified miRNA modulation in the serum of all the five mouse models. The most highly dysregulated serum miRNAs were found to be commonly upregulated in DMD, LGMD2D and LGMD2C mouse models, which all exhibit massive destruction of striated muscle tissues. Some of these miRNAs were down rather than upregulated in the EDMD mice, a model without massive myofiber destruction. The dysregulated miRNAs identified in the HCM model were different, with the exception of one dysregulated miRNA common to all pathologies. Importantly, a specific and distinctive circulating miRNA profile was identified for each studied pathological mouse model. The differential expression of a few dysregulated miRNAs in the DMD mice was further evaluated in DMD patients, providing new candidates of circulating miRNA biomarkers for DMD.

  12. Lower limb asymmetry in mechanical muscle function

    DEFF Research Database (Denmark)

    Jordan, M J; Aagaard, Per; Herzog, W

    2015-01-01

    ) for kinetic impulse (CMJ and SJ phase-specific kinetic impulse AI). Dual x-ray absorptiometry scanning was used to assess asymmetry in lower body muscle mass. Compared with controls, ACL-R skiers had increased AI in muscle mass (P 

  13. Cryopreservation of human skeletal muscle impairs mitochondrial function

    DEFF Research Database (Denmark)

    Larsen, Steen; Wright-Paradis, C; Gnaiger, E

    2012-01-01

    Previous studies have investigated if cryopreservation is a viable approach for functional mitochondrial analysis. Different tissues have been studied, and conflicting results have been published. The aim of the present study was to investigate if mitochondria in human skeletal muscle maintain...... functionality after long term cryopreservation (1 year). Skeletal muscle samples were preserved in dimethyl sulfoxide (DMSO) for later analysis. Human skeletal muscle fibres were thawed and permeabilised with saponin, and mitochondrial respiration was measured by high-resolution respirometry. The capacity...... of oxidative phosphorylation was significantly (P cryopreserved human skeletal muscle samples. Cryopreservation impaired respiration with substrates linked to Complex I more than for Complex II (P

  14. Cryopreservation of human skeletal muscle impairs mitochondrial function

    DEFF Research Database (Denmark)

    Larsen, Steen; Wright-Paradis, C; Gnaiger, E

    2012-01-01

    Previous studies have investigated if cryopreservation is a viable approach for functional mitochondrial analysis. Different tissues have been studied, and conflicting results have been published. The aim of the present study was to investigate if mitochondria in human skeletal muscle maintain...... functionality after long term cryopreservation (1 year). Skeletal muscle samples were preserved in dimethyl sulfoxide (DMSO) for later analysis. Human skeletal muscle fibres were thawed and permeabilised with saponin, and mitochondrial respiration was measured by high-resolution respirometry. The capacity...... of oxidative phosphorylation was significantly (P skeletal muscle samples. Cryopreservation impaired respiration with substrates linked to Complex I more than for Complex II (P

  15. Muscle-derived Decellularised Extracellular Matrix Improves Functional Recovery in a Rat Latissimus Dorsi Muscle Defect Model

    Science.gov (United States)

    2013-12-01

    in vivo torque production from EMG in mouse muscles injured by eccentric contractions. J Physiol 1999;515(Pt 2):609e19. 27. Gamba PG, Conconi MT, Lo... Muscle -derived decellularised extracellular matrix improves functional recovery in a rat latissimus dorsi muscle defect model Xiaoyu K. Chen a,b...maxillary injuries; Muscle function; Skeletal muscle ; Volumetric muscle loss Summary Purpose: Craniofacial maxillary injuries represent nearly 30% of all

  16. 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...

  17. Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Pearson, William G.; Hindson, David F.; Langmore, Susan E.; Zumwalt, Ann C.

    2013-01-01

    Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions

  18. Lung and respiratory muscle function in facioscapulohumeral muscular dystrophy.

    Science.gov (United States)

    Stübgen, Joerg-Patrick; Schultz, Cedric

    2009-06-01

    Pulmonary dysfunction is not a well-recognized feature of facioscapulohumeral muscular dystrophy (FSHD). The aim of this study was to establish the prevalence and type of pulmonary and respiratory muscle dysfunction in FSHD. Sixteen patients with moderately advanced FSHD and 16 healthy controls were evaluated. Standard lung and respiratory muscle function tests were performed. Diaphragm muscle inspiratory action was evaluated with transdiaphragmatic pressure measurements. Lung function tests showed an increased residual volume in five patients. There was a significant difference in global respiratory muscle function in patients versus controls; weakness was mild, and it affected expiratory more than inspiratory muscles. There was no significant difference in the diaphragm inspiratory action of patients versus controls. The dystrophic process that underlies FSHD did not significantly involve the muscles of the diaphragm, but it caused mild global respiratory muscle weakness that affected expiratory more than inspiratory muscles. It is probably not necessary to routinely monitor respiratory muscle function in ambulant FSHD patients who lack symptoms or signs of respiratory impairment.

  19. Adiposity, muscle mass and muscle strength in relation to functional decline in older persons.

    NARCIS (Netherlands)

    Schaap, L.A.; Koster, A.; Visser, M.

    2013-01-01

    Aging is associated with changes in body composition and muscle strength. This review aimed to determine the relation between different body composition measures and muscle strength measures and functional decline in older men and women. By use of relevant databases (PubMed, Embase, and CINAHL) and

  20. 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

    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...

  1. Physical function and muscle strength in sporadic inclusion body myositis

    DEFF Research Database (Denmark)

    Jørgensen, Anders N; Aagaard, Per; Nielsen, Jakob L

    2017-01-01

    INTRODUCTION: In this study, self-reported physical function, functional capacity, and isolated muscle function were investigated in sporadic inclusion body myositis (sIBM) patients. METHODS: The 36-item Short Form (SF-36) Health Survey and 2-min walk test (2MWT), timed up & go test (TUG), and 30-s...... chair stand performance were evaluated. In addition, patients were tested for knee extensor muscle strength (isokinetic dynamometer) and leg extension power (Nottingham power rig). RESULTS: TUG performance was the strongest predictor of self-reported physical function (r(2) = 0.56, P ... to sensitively predict self-perceived physical function in sIBM patients. Notably, between-limb asymmetry in lower limb muscle strength had a substantial negative impact on motor tasks involving gait function. Muscle Nerve, 2017....

  2. Desmin Cytoskeleton Linked to Muscle Mitochondrial Distribution and Respiratory Function

    Science.gov (United States)

    Milner, Derek J.; Mavroidis, Manolis; Weisleder, Noah; Capetanaki, Yassemi

    2000-01-01

    Ultrastructural studies have previously suggested potential association of intermediate filaments (IFs) with mitochondria. Thus, we have investigated mitochondrial distribution and function in muscle lacking the IF protein desmin. Immunostaining of skeletal muscle tissue sections, as well as histochemical staining for the mitochondrial marker enzymes cytochrome C oxidase and succinate dehydrogenase, demonstrate abnormal accumulation of subsarcolemmal clumps of mitochondria in predominantly slow twitch skeletal muscle of desmin-null mice. Ultrastructural observation of desmin-null cardiac muscle demonstrates in addition to clumping, extensive mitochondrial proliferation in a significant fraction of the myocytes, particularly after work overload. These alterations are frequently associated with swelling and degeneration of the mitochondrial matrix. Mitochondrial abnormalities can be detected very early, before other structural defects become obvious. To investigate related changes in mitochondrial function, we have analyzed ADP-stimulated respiration of isolated muscle mitochondria, and ADP-stimulated mitochondrial respiration in situ using saponin skinned muscle fibers. The in vitro maximal rates of respiration in isolated cardiac mitochondria from desmin-null and wild-type mice were similar. However, mitochondrial respiration in situ is significantly altered in desmin-null muscle. Both the maximal rate of ADP-stimulated oxygen consumption and the dissociation constant (K m) for ADP are significantly reduced in desmin-null cardiac and soleus muscle compared with controls. Respiratory parameters for desmin-null fast twitch gastrocnemius muscle were unaffected. Additionally, respiratory measurements in the presence of creatine indicate that coupling of creatine kinase and the adenine translocator is lost in desmin-null soleus muscle. This coupling is unaffected in cardiac muscle from desmin-null animals. All of these studies indicate that desmin IFs play a significant

  3. Effect of pelvic floor muscle exercises on pulmonary function

    OpenAIRE

    Han, DongWook; Ha, Misook

    2015-01-01

    [Purpose] This study aimed to determine the correlation between pelvic floor muscle strength and pulmonary function. In particular, we examined whether pelvic floor muscle exercises can improve pulmonary function. [Subjects] Thirty female college students aged 19?21 with no history of nervous or musculoskeletal system injury were randomly divided into experimental and control groups. [Methods] For the pulmonary function test, spirometry items included forced vital capacity and maximal volunta...

  4. Muscle function and origin of pain in fibromyalgia

    DEFF Research Database (Denmark)

    Bennett, R M; Jacobsen, Søren

    1994-01-01

    It may be concluded that both peripheral and central mechanisms may operate in the pathophysiology of both impaired muscle function and pain in FM. These mechanisms may in part be attributable to physical deconditioning and disuse of muscle secondary to the characteristic pain and fatigue so ofte...

  5. Pelvic floor muscle function in women with pelvic floor dysfunction

    DEFF Research Database (Denmark)

    Tibaek, Sigrid; Dehlendorff, Christian

    2014-01-01

    The objectives of this study were to investigate the level of pelvic floor muscle (PFM) function in women with pelvic floor dysfunction (PFD) referred by gynaecologists and urologists for in-hospital pelvic floor muscle training (PFMT), and to identity associated factors for a low level of PFM...

  6. Effects of delayed-onset muscle soreness on masticatory function

    NARCIS (Netherlands)

    Yoshida, E.; Lobbezoo, F.; Fueki, K.; Naeije, M.

    2012-01-01

    The aim was to clarify the effects of experimentally provoked delayed-onset muscle soreness (DOMS) in the jaw-closing muscles on subjective and objective measures of masticatory function. Twenty-one dentate female subjects, without pain-related signs and symptoms of temporomandibular disorders,

  7. LUNG FUNCTION AND RESPIRATORY MUSCLE STRENGTH IN OBESE IN CHILDREN

    Directory of Open Access Journals (Sweden)

    E. G. Furman

    2015-01-01

    Full Text Available Background. It is known that obesity may influence the state of respiratory function and it is associated with a number of diseases of the respiratory system. Obesity in itself, even in the absence of other known causes, can cause a feeling of shortness of breath at rest. At the same time, the cardinal symptom of respiratory muscle weakness is shortness of breath, which promotes the reduction of exercise tolerance. At the moment the problem state of respiratory function and respiratory muscles in children with different degrees of obesity is relevant and understudied. Aim. Investigation of lung function and respiratory muscle strength in obese in children. Methods. 46 children with obesity were examined, with a prevalence of obesity of mixed origin with progressive, aged 7 to 16 years. We evaluated the lung function and strength of respiratory muscles in the form of maximum inspiratory pressure at the mouth (MIP, maximal expiratory pressure at the mouth (MEP and nasal inspiratory pressure in the sniff-test (SNIP. Results. The children with obesity complained of dyspnea. The respiratory muscle dysfunction observed in the form of reduction of its forces. Reduced respiratory muscle strength ( 80% of the norm was in 44% of patients on the MIP and 38% on the MEP and was increased with increasing body mass index. Conclusion. Children with obesity need to monitor the lung function and evaluate the strength of the respiratory muscles for early detection of functional disorders of the respiratory system. 

  8. Muscle Functions and Functional Performance among Older Persons with and without Low Back Pain

    Directory of Open Access Journals (Sweden)

    Nor Azizah Ishak

    2016-01-01

    Full Text Available This study aims to compare muscle functions and functional performances between older persons with and without low back pain (LBP and to determine the association between muscle functions and functional performances. This is a cross-sectional study, involving 95 older persons (age = 70.27±7.26 years. Anthropometric characteristics, muscle functions, and functional performances were measured. Data were analyzed using ANOVA, Pearson’s correlation, and multiple linear regression. The functional performances showed no significant differences (females LBP versus non-LBP, males LBP versus non-LBP (p<0.05. For muscle functions, significant differences were found (females LBP versus non-LBP for abdominal muscle strength (p=0.006 and back muscle strength (p=0.07. In the LBP group, significant correlations were found between back and abdominal muscle strength and hand grip strength (r=0.377 and r=0.396, resp., multifidus control and lower limb function (r=0.363 in females, and back muscle strength and lower limb function (r=0.393 in males (all p<0.05. Regression analysis showed that abdominal and back muscle strengths were significant predictors of hand grip strength (p=0.041 and p=0.049, resp., and multifidus control was a significant predictor of lower limb function in females (p=0.047. This study demonstrates that older women with LBP exhibit poorer muscle functions compared to older women without LBP.

  9. Pelvic floor muscle strength and sexual function in women

    Directory of Open Access Journals (Sweden)

    Cinara Sacomori

    Full Text Available Abstract Introduction : Pelvic floor (PF muscles react to sexual stimuli with increased local blood circulation and involuntary contractions during orgasm. The training of the PF musculature helps in the improvement of the female sexual function. Objective : To verify the association between PF muscle strength and sexual function in women, controlling age and parity. Method : Cross-sectional study based on associations. The study included women who attended a reference center in Florianópolis, Santa Catarina, for a uterine cancer smear test. The Functional Evaluation of the Pelvic Floor and the Female Sexual Function Index questionnaire were used. Statistical procedures included Mann-Whitney U tests, Spearman correlation and Poisson Regression Analysis, with p < .05. Results : The mean age of the women (n = 177 was 39.05 years (SD = 13.3. Regarding PF function, 53.7% of participants presented weak or not palpable PF muscle function. Women with "good" muscle function (able to maintain contraction under examiner's resistance had significantly better indexes of sexual desire, excitement, lubrication and orgasm than women with weak/poor function. We identified that 52.5% of the women presented sexual dysfunction. Women with "poor" PF function and aged over 50 years had, respectively, 1.36 (CI95% 1.01 - 1.82 and 1.77 (CI95% 1.41 - 2.23 higher prevalence of sexual dysfunction than women with "good" PF function. Conclusions : Adult women with better PF muscle function also presented better sexual function.

  10. Muscle glycogen and cell function--Location, location, location.

    Science.gov (United States)

    Ørtenblad, N; Nielsen, J

    2015-12-01

    The importance of glycogen, as a fuel during exercise, is a fundamental concept in exercise physiology. The use of electron microscopy has revealed that glycogen is not evenly distributed in skeletal muscle fibers, but rather localized in distinct pools. In this review, we present the available evidence regarding the subcellular localization of glycogen in skeletal muscle and discuss this from the perspective of skeletal muscle fiber function. The distribution of glycogen in the defined pools within the skeletal muscle varies depending on exercise intensity, fiber phenotype, training status, and immobilization. Furthermore, these defined pools may serve specific functions in the cell. Specifically, reduced levels of these pools of glycogen are associated with reduced SR Ca(2+) release, muscle relaxation rate, and membrane excitability. Collectively, the available literature strongly demonstrates that the subcellular localization of glycogen has to be considered to fully understand the role of glycogen metabolism and signaling in skeletal muscle function. Here, we propose that the effect of low muscle glycogen on excitation-contraction coupling may serve as a built-in mechanism, which links the energetic state of the muscle fiber to energy utilization. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Skeletal Muscle Mitochondrial Function in Polycystic Ovarian Syndrome

    DEFF Research Database (Denmark)

    Rabøl, Rasmus; Svendsen, Pernille Maj; Skovbro, Mette

    2011-01-01

    Objective Polycystic ovarian syndrome (PCOS) is associated with skeletal muscle insulin resistance, which has been linked to decreased mitochondrial function. We measured mitochondrial respiration in lean and obese women with and without PCOS using high-resolution respirometry. Methods Hyperinsul...

  12. Functional Echomyography of the human denervated muscle: first results

    Directory of Open Access Journals (Sweden)

    Riccardo Zanato

    2011-03-01

    . The very high energy needed to stimulate the denervated muscles according to the Vienna home-based Functional Electrical Stimulation (h-b FES strategy demonstrates that the explored muscles are denervated. This pilot study confirms the usefulness of Functional EchoMyography in the follow-up and the positive effects of h-b FES of denervated/reinnervating muscles.

  13. LUNG FUNCTION AND RESPIRATORY MUSCLE STRENGTH IN OBESE IN CHILDREN

    OpenAIRE

    E. G. Furman; A. M. Yarulina; L. V. Sofronova

    2015-01-01

    Background. It is known that obesity may influence the state of respiratory function and it is associated with a number of diseases of the respiratory system. Obesity in itself, even in the absence of other known causes, can cause a feeling of shortness of breath at rest. At the same time, the cardinal symptom of respiratory muscle weakness is shortness of breath, which promotes the reduction of exercise tolerance. At the moment the problem state of respiratory function and respiratory muscle...

  14. Skeletal and cardiac muscle pericytes: Functions and therapeutic potential

    OpenAIRE

    Murray, IR; Baily, JE; Chen, WCW; Dar, A; Gonzalez, ZN; Jensen, AR; Petrigliano, FA; Deb, A; Henderson, NC

    2017-01-01

    Pericytes are periendothelial mesenchymal cells residing within the microvasculature. Skeletal muscle and cardiac pericytes are now recognized to fulfill an increasing number of functions in normal tissue homeostasis, including contributing to microvascular function by maintaining vessel stability and regulating capillary flow. In the setting of muscle injury, pericytes contribute to a regenerative microenvironment through release of trophic factors and by modulating local immune responses. I...

  15. Respiratory muscle function in patients with cystic fibrosis.

    Science.gov (United States)

    Dassios, Theodore; Katelari, Anna; Doudounakis, Stavros; Mantagos, Stefanos; Dimitriou, Gabriel

    2013-09-01

    Respiratory muscle function in patients with cystic fibrosis (CF) can be assessed by measurement of maximal inspiratory pressure (Pimax ), maximal expiratory pressure (Pemax ), and pressure-time index of the respiratory muscles (PTImus ). We investigated the differences in maximal respiratory pressures and PTImus between CF patients with no gross hyperinflation and healthy controls and described the effects of pulmonary function and nutrition impairment on respiratory muscle function in this group of CF patients. Forced expiratory volume in 1 sec (FEV1 ), forced vital capacity (FVC) and maximal expiratory flow between 25% and 75% of VC (MEF25-75 ), body mass index (BMI), upper arm muscle area (UAMA), Pimax , Pemax , and PTImus were assessed in 140 CF patients and in a control group of 140 healthy subjects matched for age and gender. Median Pimax and Pemax were significantly lower in CF patients compared to the controls [Pimax  = 74 (57-94) in CF vs. 84 (66-102) in controls, P = 0.009], [Pemax  = 71 (50-95) in CF vs. 84 (66-102) in controls, P function. In CF patients, PTImus was significantly negatively related to upper arm muscle area (r = 0.184, P = 0.031). These findings suggest that CF patients with no severe lung disease compared to healthy subjects exhibit impaired respiratory muscle function, while CF patients with impaired pulmonary function and nutrition indices exhibit higher PTImus values. Copyright © 2012 Wiley Periodicals, Inc.

  16. CT based muscle density predicts muscle function and health-related quality of life in patients with idiopathic inflammatory myopathies

    Science.gov (United States)

    Cleary, Laura C.; Crofford, Leslie J.; Long, Douglas; Charnigo, Richard; Clasey, Jody; Beaman, Francesca; Jenkins, Kirk A.; Fraser, Natasha; Srinivas, Archana; Dhaon, Nicole; Hanaoka, Beatriz Y.

    2016-01-01

    Objective To investigate the association of low-density (lipid-rich) muscle measured by computed tomography (CT) with skeletal muscle function and health-related quality of life in idiopathic inflammatory myopathies (IIMs). Methods Seventeen patients and ten healthy controls underwent CT of the mid-thigh to quantify high (30-100HU) and low density (0-29HU) skeletal muscle areas. Anthropometric measures, body composition, physical activity level, health-related quality of life, skeletal muscle strength, endurance and fatigue were assessed. Patients were compared against controls. The relationship of anthropometric, body composition and disease variables with measures of muscle function were examined using Spearman’s test on the patient group. Linear regression was used to assess the age-and disease-adjusted relationship of muscle quality to physical function and muscle strength. Results Patients had higher body fat% (p=0.042), trunk fat mass (p=0.042), android/gynoid fat (p=0.033) and mid-thigh low density muscle/total muscle area (p<0.001) compared to controls. Mid-thigh low density muscle/total muscle area was negatively correlated with self-reported physical function, strength and endurance; the SF-36 physical functioning (p=0.004), manual muscle testing (p=0.020), knee maximal voluntary isometric contraction/thigh mineral free lean mass (p<0.001) and the endurance step test (p<0.001), suggesting that muscle quality impacts function in IIM. Using multiple linear regression adjusted for age, global disease damage, and total fat mass, poor muscle quality as measured by mid-thigh low density muscle/total muscle area was negatively associated with SF-36 physical functioning (p= 0.009). Conclusion Mid-thigh low density muscle/ total muscle area is a good predictor of muscle strength, endurance and health-related quality of life as it pertains to physical functioning in patients with IIMs. PMID:25623494

  17. Inspiratory muscle training for the recovery of function after stroke.

    Science.gov (United States)

    Xiao, Yousheng; Luo, Man; Wang, Jin; Luo, Hongye

    2012-05-16

    Inspiratory muscle weakness has been observed in patients with stroke. Inspiratory muscle training is an intervention that has shown possible effects for functional recovery of patients with stroke. To investigate the effect and safety of inspiratory muscle training for improving activities of daily living, respiratory muscle function, quality of life and cardiorespiratory fitness after stroke. We searched the Cochrane Stroke Group's Trials Register (August 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, October Issue 4), MEDLINE (1948 to October 2011), EMBASE (1974 to October 2011), CINAHL (1982 to October 2011), AMED (1985 to October 2011), PEDro (October 2011) and four Chinese databases. In an effort to identify further published, unpublished and ongoing trials, we searched ongoing trials registers and conference proceedings, checked reference lists, and contacted authors of relevant studies and training devices manufactures. There were no language restrictions. Randomised controlled trials (RCTs) comparing inspiratory muscle training with no intervention, sham inspiratory muscle training or other cardiorespiratory training for patients with stroke were eligible. Two review authors independently assessed trial quality and extracted data. The primary outcomes were activities of daily living and respiratory muscle strength; the secondary outcomes were quality of life, cardiorespiratory fitness and adverse effects. We included two trials involving a total of 66 patients in this review. Pooling analyses of data was not possible due to considerable heterogeneity between the trials and a lack of data in both trials. One study found a significant increase in respiratory muscle strength favouring inspiratory muscle training over sham inspiratory muscle training, but there was no significant difference between groups on quality of life. The other study showed that patients receiving inspiratory muscle training were more

  18. Protein Structure-Function Relationship at Work: Learning from Myopathy Mutations of the Slow Skeletal Muscle Isoform of Troponin T.

    Science.gov (United States)

    Mondal, Anupom; Jin, J-P

    2016-01-01

    Troponin T (TnT) is the sarcomeric thin filament anchoring subunit of the troponin complex in striated muscles. A nonsense mutation in exon 11 of the slow skeletal muscle isoform of TnT (ssTnT) gene ( TNNT1 ) was found in the Amish populations in Pennsylvania and Ohio. This single nucleotide substitution causes a truncation of the ssTnT protein at Glu 180 and the loss of the C-terminal tropomyosin (Tm)-binding site 2. As a consequence, it abolishes the myofilament integration of ssTnT and the loss of function causes an autosomal recessive nemaline myopathy (NM). More TNNT1 mutations have recently been reported in non-Amish ethnic groups with similar recessive NM phenotypes. A nonsense mutation in exon 9 truncates ssTnT at Ser 108 , deleting Tm-binding site 2 and a part of the middle region Tm-binding site 1. Two splicing site mutations result in truncation of ssTnT at Leu 203 or deletion of the exon 14-encoded C-terminal end segment. Another splicing mutation causes an internal deletion of the 39 amino acids encoded by exon 8, partially damaging Tm-binding site 1. The three splicing mutations of TNNT1 all preserve the high affinity Tm-binding site 2 but still present recessive NM phenotypes. The molecular mechanisms for these mutations to cause myopathy provide interesting models to study and understand the structure-function relationship of TnT. This focused review summarizes the current knowledge of TnT isoform regulation, structure-function relationship of TnT and how various ssTnT mutations cause recessive NM, in order to promote in depth studies for further understanding the pathogenesis and pathophysiology of TNNT1 myopathies toward the development of effective treatments.

  19. Resistance Exercise Reduces Skeletal Muscle Cachexia and Improves Muscle Function in Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Salaheddin Sharif

    2011-01-01

    Full Text Available Rheumatoid arthritis (RA is a chronic, systemic, autoimmune, inflammatory disease associated with cachexia (reduced muscle and increased fat. Although strength-training exercise has been used in persons with RA, it is not clear if it is effective for reducing cachexia. A 46-year-old woman was studied to determine: (i if resistance exercise could reverse cachexia by improving muscle mass, fiber cross-sectional area, and muscle function; and (2 if elevated apoptotic signaling was involved in cachexia with RA and could be reduced by resistance training. A needle biopsy was obtained from the vastus lateralis muscle of the RA subject before and after 16 weeks of resistance training. Knee extensor strength increased by 13.6% and fatigue decreased by 2.8% Muscle mass increased by 2.1%. Average muscle fiber cross-sectional area increased by 49.7%, and muscle nuclei increased slightly after strength training from 0.08 to 0.12 nuclei/μm2. In addition, there was a slight decrease (1.6% in the number of apoptotic muscle nuclei after resistance training. This case study suggests that resistance training may be a good tool for increasing the number of nuclei per fiber area, decreasing apoptotic nuclei, and inducing fiber hypertrophy in persons with RA, thereby slowing or reversing rheumatoid cachexia.

  20. Neural correlates of visual motion processing without awareness in patients with striate cortex and pulvinar lesions.

    Science.gov (United States)

    Barleben, Maria; Stoppel, Christian M; Kaufmann, Jörn; Merkel, Christian; Wecke, Thoralf; Goertler, Michael; Heinze, Hans-Jochen; Hopf, Jens-Max; Schoenfeld, Mircea A

    2015-04-01

    Patients with striate cortex lesions experience visual perception loss in the contralateral visual field. In few patients, however, stimuli within the blind field can lead to unconscious (blindsight) or even conscious perception when the stimuli are moving (Riddoch syndrome). Using functional magnetic resonance imaging (fMRI), we investigated the neural responses elicited by motion stimulation in the sighted and blind visual fields of eight patients with lesions of the striate cortex. Importantly, repeated testing ensured that none of the patients exhibited blindsight or a Riddoch syndrome. Three patients had additional lesions in the ipsilesional pulvinar. For blind visual field stimulation, great care was given that the moving stimulus was precisely presented within the borders of the scotoma. In six of eight patients, the stimulation within the scotoma elicited hemodynamic activity in area human middle temporal (hMT) while no activity was observed within the ipsilateral lesioned area of the striate cortex. One of the two patients in whom no ipsilesional activity was observed had an extensive lesion including massive subcortical damage. The other patient had an additional focal lesion within the lateral inferior pulvinar. Fiber-tracking based on anatomical and functional markers (hMT and Pulvinar) on individual diffusion tensor imaging (DTI) data from each patient revealed the structural integrity of subcortical pathways in all but the patient with the extensive subcortical lesion. These results provide clear evidence for the robustness of direct subcortical pathways from the pulvinar to area hMT in patients with striate cortex lesions and demonstrate that ipsilesional activity in area hMT is completely independent of conscious perception. © 2014 Wiley Periodicals, Inc.

  1. Muscle ultrasound measurements and functional muscle parameters in non-dystrophic myotonias suggest structural muscle changes.

    NARCIS (Netherlands)

    Trip, J.; Pillen, S.; Faber, C.G.; Engelen, B.G.M. van; Zwarts, M.J.; Drost, G.

    2009-01-01

    Patients with non-dystrophic myotonias, including chloride (myotonia congenita) and sodium channelopathies (paramyotonia congenita/potassium aggravated myotonias), may show muscular hypertrophy in combination with some histopathological abnormalities. However, the extent of muscle changes has never

  2. Muller's muscle resection for ptosis and relationship with levator and Muller's muscle function.

    Science.gov (United States)

    Maheshwari, Rajat; Maheshwari, Sejal

    2011-06-01

    Results of Muller's muscle resection in patients with ptosis and its relationship with levator and Muller's muscle function. Prospective review of medical records of all pateints who underwent open sky Mullerectomy for correction of upper eyelid ptosis. The study period was from January 2008 to July 2009. Levator function, MRD1, Phenylepherine test result and extent of ptosis correction were recorded. Excised muscle tissue in few cases were subjected to histopathology. In 11 patients who underwent 13 mullerectomy procedures for correction of upper eyelid ptosis, MRD1 increased an average by 2.54 mm. The amount of ptosis correction was 4.28 mm in pateints with either good levator function and/or Muller's action and 1mm in patients where both responses to phenylepherine and levator functions were poor. Histopathology revealed both straited and smooth muscle tissue in the excised specimens in all cases. Mullerectomy porbably involves plication of the posterior layer of the levator aponeurosis. Results of Muller's muscle resection is good in patients with good levator function and/or good Mullers action and poor if both Muller and levator function are poor.

  3. Effects of inspiratory muscle training on pulmonary functions and muscle strength in sedentary hemodialysis patients.

    Science.gov (United States)

    El-Deen, Heba A Bahey; Alanazi, Fahad Salam; Ahmed, Khaled Takey

    2018-03-01

    [Purpose] This study was conducted to evaluate the effect of Inspiratory Muscle Trainer (IMT) on respiratory muscle strength and pulmonary functions. [Subjects and Methods] Fifteen sedentary unemployed patients were recruited from both genders who received regular hemodialysis sessions from at least three months. Those patients received Threshold IMT program for 12 weeks. Pulmonary functions and respiratory muscle strength in form of (PImax) and (PEmax) were measured by electronic spirometry and digital pressure vacuum meter respectively. Additionally oxygen saturation was measured by Finger pulse oximeter. All measurements were performed before and at the end of the treatment program after 12 weeks. [Results] The results of this study revealed significant improvement in FVC%, FEV1%, PEF%, PImax and PEmax after three months of treatment by using inspiratory muscle trainer while no significant difference was recorded regarding to FEV1/FVC% ratio and SpO 2 . [Conclusion] Inspiratory muscle trainer is an effective therapeutic technique to improve respiratory muscle strength and pulmonary functions in patients undergoing hemodialysis.

  4. Muscle function in elite master weightlifters.

    Science.gov (United States)

    Pearson, Stephen J; Young, Archie; Macaluso, Andrea; Devito, Giuseppe; Nimmo, Myra A; Cobbold, Matthew; Harridge, Stephen D R

    2002-07-01

    To determine whether explosive power and isometric strength of the lower-limb muscles in elite master Olympic weightlifters declines at a similar rate to nontrained healthy controls with increasing age. 54 elite level masters weightlifters (aged 40-87), who were competitors at the World Masters Weightlifting Championships (1999), were compared with a similar number of aged-matched, healthy untrained individuals. Isometric knee extensor strength and lower-limb explosive power were tested. Extent of antagonist co-contraction during isometric knee extension was determined by EMG and power loading characteristics by using a variable inertial system. Muscle volume was estimated using anthropometry. On average, the weightlifters were able to generate 32% more peak power (P weightlifters and controls (1.2 and 1.3% of a 45-yr-old's value per year), as did strength, but at a lower rate (0.6 and 0.5% per year). The inertial load at which the weightlifters achieved their maximal peak power output was greater (P weightlifters (P weightlifters to reach their maximal peak power was on average 13% shorter (P weightlifters and healthy controls. In spite of inertial load optimization, muscle power declined in both groups at approximately twice the rate of isometric strength. Although similar rates of decline were observed, the absolute differences between the weightlifters and controls were such that an 85-yr-old weightlifter was as powerful as a 65-yr-old control subject. This would therefore represent an apparent age advantage of approximately 20 yr for the weightlifters.

  5. Muscle endurance and mitochondrial function after chronic normobaric hypoxia: contrast of respiratory and limb muscles.

    Science.gov (United States)

    Gamboa, Jorge L; Andrade, Francisco H

    2012-02-01

    Skeletal muscle adaptation to chronic hypoxia includes loss of oxidative capacity and decrease in fiber size. However, the diaphragm may adapt differently since its activity increases in response to hypoxia. Thus, we hypothesized that chronic hypoxia would not affect endurance, mitochondrial function, or fiber size in the mouse diaphragm. Adult male mice were kept in normoxia (control) or hypoxia (hypoxia, FIO(2) = 10%) for 4 weeks. After that time, muscles were collected for histological, biochemical, and functional analyses. Hypoxia soleus muscles fatigued faster (fatigue index higher in control, 21.5 ± 2.6% vs. 13.4 ± 2.4%, p muscles, but it was 25% smaller in diaphragm (p muscles were lower: state 2 decreased 19%, state 3 31%, and state 4 18% vs. control, p muscle mitochondria had lower content of complex IV (cytochrome c oxidase), while diaphragm mitochondria had higher content of complexes IV and V (F (1)/F (0) ATP synthase) and less uncoupling protein 3 (UCP-3). These data demonstrate that diaphragm retains its endurance during chronic hypoxia, apparently due to a combination of morphometric changes and optimization of mitochondrial energy production.

  6. Vitamin D and muscle function in older people

    NARCIS (Netherlands)

    Janssen, H.C.J.P.

    2014-01-01

    Vitamin D deficiency is a worldwide problem particularly among older people, who are more susceptible due to diminished vitamin D synthesis in the skin and low dietary intake of vitamin D. Vitamin D has been associated with various (patho)physiological functions including muscle function. It is

  7. Trunk muscle co-ordination during gait: relationship between muscle function and acute low back pain.

    Science.gov (United States)

    Anders, Christoph; Scholle, Hans-Christoph; Wagner, Heiko; Puta, Christian; Grassme, Roland; Petrovitch, Alexander

    2005-12-01

    Low back pain costs billions of Euros annually in all industrialized countries. Often radiological diagnosis fails to give evidence of the pathogenesis of low back pain. Although psychophysiological characteristics have an influence, it seems that insufficient muscular spinal stabilization may play the major role in the development of low back pain. Assessment of trunk muscle stabilization activity during everyday activities is rare. Therefore, in this study healthy persons were investigated during walking on a treadmill at a speed of 4 km/h. Women (n = 16) with no history of back pain were investigated before and after a static loading situation of the spine, i.e. while wearing a waistcoat. After this loading situation four women developed pain (pain subjects). Surface EMG (SEMG) was taken from five trunk muscles of both sides. Grand averaged amplitude curves over stride, amplitude normalized curves and variation between all included strides were calculated for all muscles and subjects, respectively. The normal range of all calculated parameters was defined within the span between the 5th and the 95th percentiles of all pain free subjects. Data were evaluated according to deviations from the normal range. Already before the load situation, pain subjects showed considerable deviations from the normal range, mainly of their abdominal muscles. There was no relationship between magnitude of deviation and pain intensity, but perceived exertion was highest in those subjects who showed the most symptoms in terms of number of muscles being identified as considerably deviating from the normal range. No specific "dysfunction pattern" could be identified, which argues for highly individual mechanisms instead of a single target muscle. The results suggest cumulative effects of different disturbance levels resulting in acute back pain. Since deviations could be identified already before the pain occurred, disturbed muscle function seems to be a risk factor for developing back

  8. Kinesiophobia, Pain, Muscle Functions, and Functional Performances among Older Persons with Low Back Pain

    OpenAIRE

    Ishak, Nor Azizah; Zahari, Zarina; Justine, Maria

    2017-01-01

    Objectives This study aims (1) to determine the association between kinesiophobia and pain, muscle functions, and functional performances and (2) to determine whether kinesiophobia predicts pain, muscle functions, and functional performance among older persons with low back pain (LBP). Methods This is a correlational study, involving 63 institutionalized older persons (age = 70.98 ? 7.90 years) diagnosed with LBP. Anthropometric characteristics (BMI) and functional performances (lower limb fu...

  9. Keratin Hydrogel Enhances In Vivo Skeletal Muscle Function in a Rat Model of Volumetric Muscle Loss.

    Science.gov (United States)

    Passipieri, J A; Baker, H B; Siriwardane, Mevan; Ellenburg, Mary D; Vadhavkar, Manasi; Saul, Justin M; Tomblyn, Seth; Burnett, Luke; Christ, George J

    2017-06-01

    Volumetric muscle loss (VML) injuries exceed the considerable intrinsic regenerative capacity of skeletal muscle, resulting in permanent functional and cosmetic deficits. VML and VML-like injuries occur in military and civilian populations, due to trauma and surgery as well as due to a host of congenital and acquired diseases/syndromes. Current therapeutic options are limited, and new approaches are needed for a more complete functional regeneration of muscle. A potential solution is human hair-derived keratin (KN) biomaterials that may have significant potential for regenerative therapy. The goal of these studies was to evaluate the utility of keratin hydrogel formulations as a cell and/or growth factor delivery vehicle for functional muscle regeneration in a surgically created VML injury in the rat tibialis anterior (TA) muscle. VML injuries were treated with KN hydrogels in the absence and presence of skeletal muscle progenitor cells (MPCs), and/or insulin-like growth factor 1 (IGF-1), and/or basic fibroblast growth factor (bFGF). Controls included VML injuries with no repair (NR), and implantation of bladder acellular matrix (BAM, without cells). Initial studies conducted 8 weeks post-VML injury indicated that application of keratin hydrogels with growth factors (KN, KN+IGF-1, KN+bFGF, and KN+IGF-1+bFGF, n = 8 each) enabled a significantly greater functional recovery than NR (n = 7), BAM (n = 8), or the addition of MPCs to the keratin hydrogel (KN+MPC, KN+MPC+IGF-1, KN+MPC+bFGF, and KN+MPC+IGF-1+bFGF, n = 8 each) (p < 0.05). A second series of studies examined functional recovery for as many as 12 weeks post-VML injury after application of keratin hydrogels in the absence of cells. A significant time-dependent increase in functional recovery of the KN, KN+bFGF, and KN+IGF+bFGF groups was observed, relative to NR and BAM implantation, achieving as much as 90% of the maximum possible functional recovery. Histological findings from harvested

  10. Assessment of muscle function in severely burned children.

    Science.gov (United States)

    Alloju, Shashi M; Herndon, David N; McEntire, Serina J; Suman, Oscar E

    2008-06-01

    The posttraumatic response to a severe burn leads to marked and prolonged skeletal muscle catabolism and weakness, which persist despite standard rehabilitation programs of occupational and physical therapy. We investigated the degree to which the prolonged skeletal muscle catabolism affects the muscle function of children 6 months after severe burn. Burned children, with >40% total body surface area burned, were assessed at 6 months after burn in respect to lean body mass and leg muscle strength at 150 degrees /s. Lean body mass was assessed using dual-energy X-ray absorptiometry. Leg muscle strength was assessed using isokinetic dynamometry. Nonburned children were assessed similarly, and served as controls. We found that severely burned children (n=33), relative to nonburned children (n=46) had significantly lower lean body mass. Additionally they had significantly lower peak torque as well total work performance using the extensors of the thigh. Our results serve as an objective and a practical clinical approach for assessing muscle function and also aid in establishing potential rehabilitation goals, and monitoring progress towards these goals in burned children.

  11. Abdominal syndromes and functional ability in the elderly

    DEFF Research Database (Denmark)

    Kay, L; Avlund, K

    1994-01-01

    by an occupational therapist who evaluated their functional ability. Among the survivors, 94% participated in a follow-up study five years later. Functional ability was registered on validated scales constructed for its measurement in a normal elderly population. It was found that both syndromes occurred more often...... that abdominal syndromes are associated to functional ability, suggesting that there is a diffuse disorder affecting both smooth and striated muscles....

  12. YAP-mediated mechanotransduction in skeletal muscle

    Directory of Open Access Journals (Sweden)

    Martina eFischer

    2016-02-01

    Full Text Available Skeletal muscle is not only translating chemical energy into mechanical work, it is also a highly adaptive and regenerative tissue whose architecture and functionality is determined by its mechanical and physical environment. Processing intra- and extracellular mechanical signaling cues contributes to the regulation of cell growth, survival, migration and differentiation. Yes-associated Protein (YAP, a transcriptional coactivator downstream of the Hippo pathway and its paralogue, the transcriptional co-activator with PDZ-binding motif (TAZ, were recently found to play a key role in mechanotransduction in various tissues including skeletal muscle. Furthermore, YAP/TAZ modulate myogenesis and muscle regeneration and abnormal YAP activity has been reported in muscular dystrophy and rhabdomyosarcoma. Here, we summarize the current knowledge of mechanosensing and -signaling in striated muscle. We highlight the role of YAP signaling and discuss the different routes and hypotheses of its regulation in the context of mechanotransduction.

  13. It is not just muscle mass: a review of muscle quality, composition and metabolism during ageing as determinants of muscle function and mobility in later life.

    Science.gov (United States)

    McGregor, Robin A; Cameron-Smith, David; Poppitt, Sally D

    2014-01-01

    Worldwide estimates predict 2 billion people will be aged over 65 years by 2050. A major current challenge is maintaining mobility and quality of life into old age. Impaired mobility is often a precursor of functional decline, disability and loss of independence. Sarcopenia which represents the age-related decline in muscle mass is a well-established factor associated with mobility limitations in older adults. However, there is now evidence that not only changes in muscle mass but other factors underpinning muscle quality including composition, metabolism, aerobic capacity, insulin resistance, fat infiltration, fibrosis and neural activation may also play a role in the decline in muscle function and impaired mobility associated with ageing. Importantly, changes in muscle quality may precede loss of muscle mass and therefore provide new opportunities for the assessment of muscle quality particularly in middle-aged adults who could benefit from interventions to improve muscle function. This review will discuss the accumulating evidence that in addition to muscle mass, factors underpinning muscle quality influence muscle function and mobility with age. Further development of tools to assess muscle quality in community settings is needed. Preventative diet, exercise or treatment interventions particularly in middle-aged adults at the low end of the spectrum of muscle function may help preserve mobility in later years and improve healthspan.

  14. Effects of strenuous exercise with eccentric muscle contraction: physiological and functional aspects of human skeletal muscle.

    Science.gov (United States)

    Yanagisawa, Osamu; Kurihara, Toshiyuki; Okumura, Koji; Fukubayashi, Toru

    2010-01-01

    we used magnetic resonance (MR) imaging and ultrasonography in combination with a dynamometer to assess physiological and functional aspects of the skeletal muscles after strenuous exercise that included eccentric contraction. seven male subjects (mean age, 21.7 years) performed ankle plantar flexion that included eccentric contraction and underwent diffusion-weighted MR imaging for calculation of the apparent diffusion coefficient (ADC) of the triceps surae muscles. We used ultrasonography combined with a dynamometer to measure the displacement of the myotendinous junction (MTJ) of the medial gastrocnemius and maximal isometric force during ankle plantar flexion. We also assessed the level of muscle soreness of the calf using a visual analogue scale. We measured these parameters before exercise and one, 2, 3, 5, and 8 days after exercise and examined significant changes from the pre-exercise value using repeated-measures analysis of variance with Dunnett's test for each measurement parameter. one day after exercise, we observed increased muscle soreness (Peccentric contraction manifests as muscle soreness and dysfunction early after exercise and later increases water diffusion within damaged muscle.

  15. Glutamine Synthetase in Muscle Is Required for Glutamine Production during Fasting and Extrahepatic Ammonia Detoxification

    NARCIS (Netherlands)

    He, Youji; Hakvoort, Theodorus B. M.; Köhler, S. Eleonore; Vermeulen, Jacqueline L. M.; de Waart, D. Rudi; de Theije, Chiel; ten Have, Gabrie A. M.; van Eijk, Hans M. H.; Kunne, Cindy; Labruyere, Wilhelmina T.; Houten, Sander M.; Sokolovic, Milka; Ruijter, Jan M.; Deutz, Nicolaas E. P.; Lamers, Wouter H.

    2010-01-01

    The main endogenous source of glutamine is de novo synthesis in striated muscle via the enzyme glutamine synthetase (GS). The mice in which GS is selectively but completely eliminated from striated muscle with the Cre-loxP strategy (GS-KO/M mice) are, nevertheless, healthy and fertile. Compared with

  16. Why adductor magnus muscle is large: the function based on muscle morphology in cadavers.

    Science.gov (United States)

    Takizawa, M; Suzuki, D; Ito, H; Fujimiya, M; Uchiyama, E

    2014-02-01

    The aim of this study was to examine anatomical properties of the adductor magnus through a detailed classification, and to hypothesize its function and size to gather enough information about morphology. Ten cadaveric specimens of the adductor magnus were used. The muscle was separated into four portios (AM1-AM4) based on the courses of the corresponding perforating arteries, and its volume, muscle length, muscle fiber length and physiological cross-sectional area were assessed. The architectural characteristics of these four portions of the adductor magnus were then classified with the aid of principal component analysis. The results led us into demarcating the most proximal part of the adductor magnus (AM1) from the remaining parts (AM2, AM3, and AM4). Classification of the adductor magnus in terms of architectural characteristics differed from the more traditional anatomical distinction. The AM2, AM3, and AM4, having longer muscle fiber lengths than the AM1, appear to be designed as displacers for moving the thigh through a large range of motion. The AM1 appears instead to be oriented principally toward stabilizing the hip joint. The large mass of the adductor magnus should thus be regarded as a complex of functionally differentiable muscle portions. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. 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.

  18. Insights from diploblasts; the evolution of mesoderm and muscle.

    Science.gov (United States)

    Burton, Patrick Michael

    2008-01-15

    The origin of both mesoderm and muscle are central questions in metazoan evolution. The majority of metazoan phyla are triploblasts, possessing three discrete germ layers. Attention has therefore been focused on two outgroups to triploblasts, Cnidaria and Ctenophora. Modern texts describe these taxa as diploblasts, lacking a mesodermal germ layer. However, some members of Medusozoa, one of two subphyla within Cnidaria, possess tissue independent of either the ectoderm or endoderm referred to as the entocodon. Furthermore, members of both Cnidaria and Ctenophora have been described as possessing striated muscle, a mesodermal derivative. While it is widely accepted that the ancestor of Eumetazoa was diploblastic, homology of the entocodon and mesoderm as well as striated muscle within Eumetazoa has been suggested. This implies a potential triploblastic ancestor of Eumetazoa possessing striated muscle. In the following review, I examine the evidence for homology of both muscle and mesoderm. Current data support a diploblastic ancestor of cnidarians, ctenophores, and triploblasts lacking striated muscle.

  19. Resistance training, insulin sensitivity and muscle function in the elderly

    DEFF Research Database (Denmark)

    Dela, Flemming; Kjaer, Michael

    2006-01-01

    Ageing is associated with a loss in both muscle mass and in the metabolic quality of skeletal muscle. This leads to sarcopenia and reduced daily function, as well as to an increased risk for development of insulin resistance and type 2 diabetes. A major part, but not all, of these changes...... are associated with an age-related decrease in the physical activity level and can be counteracted by increased physical activity of a resistive nature. Strength training has been shown to improve insulin-stimulated glucose uptake in both healthy elderly individuals and patients with manifest diabetes...

  20. The striated MR nephrogram, not a reflection of pathology

    Energy Technology Data Exchange (ETDEWEB)

    Trout, Andrew T.; Care, Marguerite M.; Towbin, Alexander J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology - MLC 5031, Cincinnati, OH (United States); Zhang, Bin [Cincinnati Children' s Hospital Medical Center, Division of Biostatistics and Epidemiology, Cincinnati, OH (United States)

    2015-10-15

    We have intermittently observed low signal striations in the kidneys on delayed post-contrast MR exams of the spine. While we suspected these striations were due to concentrated gadolinium, the clinical importance of this finding was uncertain. To describe the striated MR nephrogram (low signal striations in the kidney) and assess its clinical relevance. Retrospective review of delayed post-contrast MRIs of the spine (mean: 45 min after contrast administration). The presence of the striated MR nephrogram was correlated with imaging parameters (field strength, time since contrast), and findings (gadolinium in the bladder, inferior vena cava and aorta diameters) and with clinical factors (history of renal disease, laboratory values). Seven hundred seventy-three exams performed on 229 patients, 8.3 ± 5.3 years of age, were reviewed. The striated MR nephrogram was observed in 102/773 examinations (13.2%) and was present on at least one study in 54/229 patients (23.6%). The presence of striations was associated with the specific magnet on which the exam was performed (P < 0.01) but not with magnet field strength. Serum creatinine was minimally lower in patients with striations (0.43 ± 0.12 vs. 0.49 ± 0.18 mg/dL, P = 0.002), but no other clinical or historical data, including time from contrast administration (P = 0.54), fluid status (P = 0.17) and clinical history of renal disease (P = 0.14), were predictive of the presence of striations. The striated MR nephrogram was observed in 13% of delayed post-contrast MR exams of the spine. Precipitating factors are unclear, but the striated nephrogram does not appear to be a marker of clinically apparent renal dysfunction. (orig.)

  1. Association between preterm labour and pelvic floor muscle function.

    Science.gov (United States)

    Aran, Turhan; Pekgöz, Ipek; Bozkaya, Hasan; Osmanagaoglu, Mehmet A

    2018-03-23

    We hypothesised that the pressure on the cervix increases with advancing gestation and it may lead to a cervical shortening and cause preterm labour in women with weak pelvic floor muscles. The aim of this prospective study was to measure vaginal resting pressure and pelvic floor muscle strength in the first trimester of pregnancy and to investigate their effects on labour. A study was conducted on the pregnant women with a low risk for preterm birth. The pelvic floor muscle strength and vaginal resting pressure were assessed in 320 pregnant women at their first trimester with a vaginal pressure measurement device. Fifty-two pregnant women were hospitalised for tocolytic therapy because of spontaneous preterm labour. Thirty-two of them (10.2%) had a preterm delivery despite the tocolytic therapy. Both the vaginal resting pressure (p = .009, 95%CI: 0.8; 5.9) and the pelvic floor muscle strength (p = .01, 95%CI: 3.5; 13.1) were significantly lower in the women with a preterm labour. Impact statement What is already known on this subject? The pelvic floor muscles have an essential role in continence and provide support to the pelvic organs. They also have an impact on labour. The pelvic floor muscles should distend to allow the passage of the foetus during labour. The rotation and flexion of the foetal head is due to the pelvic floor resistance. The effect of a vaginal birth on the pelvic floor's function is readily understood. On the other hand, the effect of the pelvic floor muscle function on labour is still controversial. What do the results of this study add? This prospective study showed that there is a negative association between the pelvic floor muscle strength and preterm labour. This is the first clinical study indicating that weak pelvic floor muscles may cause a preterm labour. What are the implications of these findings for clinical practice and/or further research? Pelvic floor physical therapy may be an alternative preventive strategy to reduce

  2. Transient impairments in single muscle fibre contractile function after prolonged cycling in elite endurance athletes

    DEFF Research Database (Denmark)

    Hvid, L G; Gejl, Kasper Degn; Bech, R D

    2013-01-01

    Prolonged muscle activity impairs whole-muscle performance and function. However, little is known about the effects of prolonged muscle activity on the contractile function of human single muscle fibres. The purpose of this study was to investigate the effects of prolonged exercise and subsequent...

  3. Skeletal muscle atrophy and the E3 ubiquitin ligases MuRF1 and MAFbx/atrogin-1

    Science.gov (United States)

    Baehr, Leslie M.

    2014-01-01

    Muscle RING finger 1 (MuRF1) and muscle atrophy F-box (MAFbx)/atrogin-1 were identified more than 10 years ago as two muscle-specific E3 ubiquitin ligases that are increased transcriptionally in skeletal muscle under atrophy-inducing conditions, making them excellent markers of muscle atrophy. In the past 10 years much has been published about MuRF1 and MAFbx with respect to their mRNA expression patterns under atrophy-inducing conditions, their transcriptional regulation, and their putative substrates. However, much remains to be learned about the physiological role of both genes in the regulation of mass and other cellular functions in striated muscle. Although both MuRF1 and MAFbx are enriched in skeletal, cardiac, and smooth muscle, this review will focus on the current understanding of MuRF1 and MAFbx in skeletal muscle, highlighting the critical questions that remain to be answered. PMID:25096180

  4. Cricothyroid muscle function and vocal fold stability in exercising horses.

    Science.gov (United States)

    Holcombe, Susan J; Rodriguez, Katie; Lane, Jennifer; Caron, John P

    2006-08-01

    To determine (1) if the cricothyroid muscle had respiratory-related electromyographic (EMG) activity that increased with respiratory effort and (2) if bilateral cricothyroid myotomy resulted in vocal fold instability and collapse in exercising horses. Experimental. Seven (3 EMG; 4 cricothyroid myotomy) Standardbred horses. Three horses exercised on a treadmill at speeds corresponding to the speed that produced maximum heart rate (HR(max)), 75% of maximum heart rate (HR(75%max)), and 50% of maximum heart rate (HR(50%max)) for 60 seconds at each speed while EMG activity of the cricothyroid muscle and nasopharyngeal pressures were measured. Another 4 normal horses were exercised on the treadmill at HR(max) and HR(75%max) for 60 seconds at each speed before and after bilateral cricothyroid myotomy. Upper airway pressures were measured and videoendoscopic examinations were performed and videotaped at each speed. Peak phasic EMBG activity of the cricothyroid muscle was coincident with inspiration and increased with treadmill speed. Bilateral cricothyroid myotomy resulted in vocal fold collapse in all horses. Mean peak inspiratory pressures were significantly more negative compared with control values at both HR(max) and HR(75%max). Cricothyroid muscle dysfunction may be implicated in vocal fold collapse and likely causes inspiratory airway obstruction in exercising horses. Conditions compromising cricothyroid muscle function or motor innervation could result in vocal fold collapse.

  5. Soluble Milk Proteins Improve Muscle Mass Recovery after Immobilization-Induced Muscle Atrophy in Old Rats but Do not Improve Muscle Functional Property Restoration.

    Science.gov (United States)

    Verney, J; Martin, V; Ratel, S; Chavanelle, V; Bargetto, M; Etienne, M; Chaplais, E; Le Ruyet, P; Bonhomme, C; Combaret, L; Guillet, C; Boisseau, N; Sirvent, P; Dardevet, D

    2017-01-01

    Effect of 3 different dairy protein sources on the recovery of muscle function after limb immobilization in old rats. Longitudinal animal study. Institut National de la Recherche Agronomique (INRA). The study took part in a laboratory setting. Old rats were subjected to unilateral hindlimb immobilization for 8 days and then allowed to recover with 3 different dietary proteins: casein, soluble milk proteins or whey proteins for 49 days. Body weight, muscle mass, muscle fibre size, isometric, isokinetic torque, muscle fatigability and muscle oxidative status were measured before and at the end of the immobilization period and during the recovery period i.e 7, 21, 35 and 49 days post immobilization. In contrast to the casein diet, soluble milk proteins and whey proteins were efficient to favor muscle mass recovery after cast immobilization during aging. By contrast, none of the 3 diary proteins was able to improve muscle strength, power and fatigability showing a discrepancy between the recovery of muscle mass and function. However, the soluble milk proteins allowed a better oxidative capacity in skeletal muscle during the rehabilitation period. Whey proteins and soluble milk proteins improve muscle mass recovery after immobilization-induced muscle atrophy in old rats but do not allow muscle functional property restoration.

  6. Abdominal muscle function and incisional hernia: a systematic review.

    Science.gov (United States)

    Jensen, K K; Kjaer, M; Jorgensen, L N

    2014-08-01

    Although ventral incisional hernia (VIH) repair in patients is often evaluated in terms of hernia recurrence rate and health-related quality of life, there is no clear consensus regarding optimal operative treatment based on these parameters. It was proposed that health-related quality of life depends largely on abdominal muscle function (AMF), and the present review thus evaluates to what extent AMF is influenced by VIH and surgical repair. The PubMed and EMBASE databases were searched for articles following a systematic strategy for inclusion. A total of seven studies described AMF in relation to VIH. Five studies examined AMF using objective isokinetic dynamometers to determine muscle strength, and two studies examined AMF by clinical examination-based muscle tests. Both equipment-related and functional muscle tests exist for use in patients with VIH, but very few studies have evaluated AMF in VIH. There are no randomized controlled studies to describe the impact of VIH repair on AMF, and no optimal surgical treatment in relation to AMF after VIH repair can be advocated for at this time.

  7. Kinesiophobia, Pain, Muscle Functions, and Functional Performances among Older Persons with Low Back Pain

    Directory of Open Access Journals (Sweden)

    Nor Azizah Ishak

    2017-01-01

    Full Text Available Objectives. This study aims (1 to determine the association between kinesiophobia and pain, muscle functions, and functional performances and (2 to determine whether kinesiophobia predicts pain, muscle functions, and functional performance among older persons with low back pain (LBP. Methods. This is a correlational study, involving 63 institutionalized older persons (age = 70.98±7.90 years diagnosed with LBP. Anthropometric characteristics (BMI and functional performances (lower limb function, balance and mobility, and hand grip strength were measured. Muscle strength (abdominal and back muscle strength was assessed using the Baseline® Mechanical Push/Pull Dynamometer, while muscle control (transverse abdominus and multifidus was measured by using the Pressure Biofeedback Unit. The pain intensity and the level of kinesiophobia were measured using Numerical Rating Scale and Tampa Scale of Kinesiophobia, respectively. Data were analyzed using Pearson’s correlation coefficients and multivariate linear regressions. Results. No significant correlations were found between kinesiophobia and pain and muscle functions (all p>0.05. Kinesiophobia was significantly correlated with mobility and balance (p=0.038, r=0.263. Regressions analysis showed that kinesiophobia was a significant predictor of mobility and balance (p=0.038. Conclusion. We can conclude that kinesiophobia predicted mobility and balance in older persons with LBP. Kinesiophobia should be continuously assessed in clinical settings to recognize the obstacles that may affect patient’s compliance towards a rehabilitation program in older persons with LBP.

  8. Kinesiophobia, Pain, Muscle Functions, and Functional Performances among Older Persons with Low Back Pain.

    Science.gov (United States)

    Ishak, Nor Azizah; Zahari, Zarina; Justine, Maria

    2017-01-01

    This study aims (1) to determine the association between kinesiophobia and pain, muscle functions, and functional performances and (2) to determine whether kinesiophobia predicts pain, muscle functions, and functional performance among older persons with low back pain (LBP). This is a correlational study, involving 63 institutionalized older persons (age = 70.98 ± 7.90 years) diagnosed with LBP. Anthropometric characteristics (BMI) and functional performances (lower limb function, balance and mobility, and hand grip strength) were measured. Muscle strength (abdominal and back muscle strength) was assessed using the Baseline® Mechanical Push/Pull Dynamometer, while muscle control (transverse abdominus and multifidus) was measured by using the Pressure Biofeedback Unit. The pain intensity and the level of kinesiophobia were measured using Numerical Rating Scale and Tampa Scale of Kinesiophobia, respectively. Data were analyzed using Pearson's correlation coefficients and multivariate linear regressions. No significant correlations were found between kinesiophobia and pain and muscle functions (all p > 0.05). Kinesiophobia was significantly correlated with mobility and balance ( p = 0.038, r = 0.263). Regressions analysis showed that kinesiophobia was a significant predictor of mobility and balance ( p = 0.038). We can conclude that kinesiophobia predicted mobility and balance in older persons with LBP. Kinesiophobia should be continuously assessed in clinical settings to recognize the obstacles that may affect patient's compliance towards a rehabilitation program in older persons with LBP.

  9. Effects of aging on muscle mechanical function and muscle fiber morphology during short-term immobilization and subsequent retraining

    DEFF Research Database (Denmark)

    Hvid, Lars; Aagaard, Per; Justesen, Lene

    2010-01-01

    Very little attention has been given to the combined effects of aging and disuse as separate factors causing deterioration in muscle mechanical function. Thus the purpose of this study was to investigate the effects of 2 wk of immobilization followed by 4 wk of retraining on knee extensor muscle...... to the deleterious effects of short-term muscle disuse on muscle fiber size and rapid force capacity than YM. Furthermore, OM seems to require longer time to recover and regain rapid muscle force capacity, which may lead to a larger risk of falling in aged individuals after periods of short-term disuse....

  10. Effects of aging on muscle mechanical function and muscle fiber morphology during short-term immobilization and subsequent retraining

    DEFF Research Database (Denmark)

    Hvid, Lars; Aagaard, Per; Justesen, Lene

    2010-01-01

    to the deleterious effects of short-term muscle disuse on muscle fiber size and rapid force capacity than YM. Furthermore, OM seems to require longer time to recover and regain rapid muscle force capacity, which may lead to a larger risk of falling in aged individuals after periods of short-term disuse.......Very little attention has been given to the combined effects of aging and disuse as separate factors causing deterioration in muscle mechanical function. Thus the purpose of this study was to investigate the effects of 2 wk of immobilization followed by 4 wk of retraining on knee extensor muscle...

  11. Caspase-12 ablation preserves muscle function in the mdx mouse

    Science.gov (United States)

    Moorwood, Catherine; Barton, Elisabeth R.

    2014-01-01

    Duchenne muscular dystrophy (DMD) is a devastating muscle wasting disease caused by mutations in dystrophin. Several downstream consequences of dystrophin deficiency are triggers of endoplasmic reticulum (ER) stress, including loss of calcium homeostasis, hypoxia and oxidative stress. During ER stress, misfolded proteins accumulate in the ER lumen and the unfolded protein response (UPR) is triggered, leading to adaptation or apoptosis. We hypothesized that ER stress is heightened in dystrophic muscles and contributes to the pathology of DMD. We observed increases in the ER stress markers BiP and cleaved caspase-4 in DMD patient biopsies, compared with controls, and an increase in multiple UPR pathways in muscles of the dystrophin-deficient mdx mouse. We then crossed mdx mice with mice null for caspase-12, the murine equivalent of human caspase-4, which are resistant to ER stress. We found that deleting caspase-12 preserved mdx muscle function, resulting in a 75% recovery of both specific force generation and resistance to eccentric contractions. The compensatory hypertrophy normally found in mdx muscles was normalized in the absence of caspase-12; this was found to be due to decreased fibre sizes, and not to a fibre type shift or a decrease in fibrosis. Fibre central nucleation was not significantly altered in the absence of caspase-12, but muscle fibre degeneration found in the mdx mouse was reduced almost to wild-type levels. In conclusion, we have identified heightened ER stress and abnormal UPR signalling as novel contributors to the dystrophic phenotype. Caspase-4 is therefore a potential therapeutic target for DMD. PMID:24879640

  12. Peripheral Nerve Function and Lower Extremity Muscle Power in Older Men

    DEFF Research Database (Denmark)

    Ward, Rachel E; Caserotti, Paolo; Faulkner, Kimberly

    2014-01-01

    To assess whether sensorimotor peripheral nerve function is associated with muscle power in community-dwelling older men.......To assess whether sensorimotor peripheral nerve function is associated with muscle power in community-dwelling older men....

  13. Functional Effects of Hyperthyroidism on Cardiac Papillary Muscle in Rats

    Directory of Open Access Journals (Sweden)

    Fabricio Furtado Vieira

    Full Text Available Abstract Background: Hyperthyroidism is currently recognized to affect the cardiovascular system, leading to a series of molecular and functional changes. However, little is known about the functional influence of hyperthyroidism in the regulation of cytoplasmic calcium and on the sodium/calcium exchanger (NCX in the cardiac muscle. Objectives: To evaluate the functional changes in papillary muscles isolated from animals with induced hyperthyroidism. Methods: We divided 36 Wistar rats into a group of controls and another of animals with hyperthyroidism induced by intraperitoneal T3 injection. We measured in the animals' papillary muscles the maximum contraction force, speed of contraction (+df/dt and relaxation (-df/dt, contraction and relaxation time, contraction force at different concentrations of extracellular sodium, post-rest potentiation (PRP, and contraction force induced by caffeine. Results: In hyperthyroid animals, we observed decreased PRP at all rest times (p < 0.05, increased +df/dt and -df/dt (p < 0.001, low positive inotropic response to decreased concentration of extracellular sodium (p < 0.001, reduction of the maximum force in caffeine-induced contraction (p < 0.003, and decreased total contraction time (p < 0.001. The maximal contraction force did not differ significantly between groups (p = 0.973. Conclusion: We hypothesize that the changes observed are likely due to a decrease in calcium content in the sarcoplasmic reticulum, caused by calcium leakage, decreased expression of NCX, and increased expression of a-MHC and SERCA2.

  14. Effects of Kinesio Tape application to quadriceps muscles on isokinetic muscle strength, gait, and functional parameters in patients with stroke.

    Science.gov (United States)

    Ekiz, Timur; Aslan, Meryem Doğan; Özgirgin, Neşe

    2015-01-01

    The aim of this study was to evaluate the effects of Kinesio Tape (KT) application to quadriceps muscles on isokinetic muscle strength, gait, and functional parameters in patients with stroke. Twenty-four patients were allocated into KT and control groups. All patients participated in the same conventional rehabilitation program 5 times/wk for 4 wk. In addition, KT was applied to quadriceps muscles bilaterally to the patients in the KT group. Compared with baseline, peak torque levels increased significantly in both groups (all p 0.05). KT application to quadriceps muscles in addition to conventional exercises for 4 wk is effective on isokinetic but not functional parameters.

  15. Immunocytochemical electron microscopic study and western blot analysis of paramyosin in different invertebrate muscle cell types of the fruit fly Drosophila melanogaster, the earthworm Eisenia foetida, and the snail Helix aspersa.

    Science.gov (United States)

    Royuela, M; García-Anchuelo, R; Arenas, M I; Cervera, M; Fraile, B; Paniagua, R

    1996-04-01

    The presence and distribution pattern of paramyosin have been examined in different invertebrate muscle cell types by means of Western blot analysis and electron microscopy immunogold labelling. The muscles studied were: transversely striated muscle with continuous Z lines (flight muscle from Drosophila melanogaster), transversely striated muscle with discontinuous Z lines (heart muscle from the snail Helix aspersa), obliquely striated body wall muscle from the earthworm Eisenia foetida, and smooth muscles (retractor muscle from the snail and pseudoheart outer muscular layer from the earthworm). Paramyosin-like immunoreactivity was localized in thick filaments of all muscles studied. Immunogold particle density was similar along the whole thick filament length in insect flight muscle but it predominated in filament tips of fusiform thick filaments in both snail heart and earthworm body wall musculature when these filaments were observed in longitudinal sections. In obliquely sectioned thick filaments, immunolabelling was more abundant at the sites where filaments disappeared from the section. These results agree with the notion that paramyosin extended along the whole filament length, but that it can only be immunolabelled when it is not covered by myosin. In all muscles examined, immunolabelling density was lower in cross-sectioned myofilaments than in longitudinally sectioned myofilaments. This suggests that paramyosin does not form a continuous filament. The results of a semiquantitative analysis of paramyosin-like immunoreactivity indicated that it was more abundant in striated than in smooth muscles, and that, within striated muscles, transversely striated muscles contain more paramyosin than obliquely striated muscles.

  16. Striated nephrogram as an incidental finding in MRI examination of children; Streifiges Nephrogramm als Zufallsbefund nach Kontrastmittelgabe bei Kindern in der MRT

    Energy Technology Data Exchange (ETDEWEB)

    Strocka, S.; Sorge, I.; Ritter, L.; Hirsch, F.W. [Leipzig Univ. (Germany). Dept. of Pediatric Radiology

    2016-01-15

    A highly striated contrast pattern of the kidneys occasionally appears in abdominal MRI examinations of children following the administration of gadolinium. As this phenomenon is well known but has not yet been explicitly described in literature, we investigated how frequently and in which clinical context this occurred. 855 abdominal MRI examinations with contrast media of 362 children between 2006 and 2014 were analysed retrospectively. A striated renal parenchyma was found in a total of nine children and eleven examinations (1.3 % of examinations) and did only occur at a field strength of 3 Tesla. Of these children, seven had previously had tumors and chemotherapy. In two children there was no evidence of a previously serious condition with medications or a kidney disease. All of them had a normal renal function. A noticeably striated nephrogram in the later phase of an MRI examination following administration of gadolinium may appear as an incidental finding in examinations at 3 Tesla without pathological relevance.

  17. Effects of acupuncture on symptoms and muscle function in delayed-onset muscle soreness.

    Science.gov (United States)

    Hübscher, Markus; Vogt, Lutz; Bernhörster, Marcus; Rosenhagen, Andreas; Banzer, Winfried

    2008-10-01

    This study was done to investigate the effects of a standardized acupuncture treatment on symptoms and muscle function in exercise-induced delayed-onset muscle soreness (DOMS). A prospective, randomized, controlled, observer and subject-blinded trial was undertaken. Twenty-two (22) healthy subjects (22-30 years; 10 males and 12 females) were randomly assigned to three treatment groups: real acupuncture (deep needling at classic acupuncture points and tender points; n = 7), sham-acupuncture (superficial needling at nonacupuncture points; n = 8), and control (no needling; n = 7). DOMS of the nondominant elbow-flexors was experimentally induced through eccentric contractions until exhaustion. The outcome measures were pain perception (visual analogue scale; VAS; range: 0-10 cm), mechanical pain threshold (MPT; pressure algometer), and maximum isometric voluntary force (MIVF; force transducer). Treatment was applied immediately, 24 and 48 hours after DOMS induction. Measurements of MPT and MIVF were made prior to DOMS induction as well as before and after every treatment session. VAS data were acquired after DOMS induction as well as pre- and post-treatment. Final pain, MPT, and MIVF measurements were performed 72 hours after DOMS induction. Following nonparametric testing, there were no significant differences between groups in outcome measures at baseline. After 72 hours, pain perception (VAS) was significantly lower in the acupuncture group compared to the sham acupuncture and control subjects. However, the mean MPT and MIVF scores were not significantly different between groups. Although acupuncture seemed to have no effects on mechanical pain threshold and muscle function, it proved to reduce perceived pain arising from exercise-induced muscle soreness.

  18. Functional changes of human quadriceps muscle injured by eccentric exercise

    Directory of Open Access Journals (Sweden)

    F.V. Serrão

    2003-06-01

    Full Text Available The present study evaluated functional changes of quadriceps muscle after injury induced by eccentric exercise. Maximal isometric torque of quadriceps and the surface electromyography (root mean square, RMS, and median frequency, MDF of the vastus medialis oblique (VMO and vastus lateralis (VL muscles were examined before, immediately after and during the first 7 days after injury. Serum creatine kinase (CK levels and magnetic resonance imaging (MRI were used to identify muscle injury. The subject was used as her own control and percent refers to pre-injury data. Experiments were carried out with a sedentary 23-year-old female. Injury was induced by 4 bouts of 15 maximal isokinetic eccentric contractions (angular velocity of 5º/s; range of motion from 40º to 110º of knee flexion. The isometric torque of the quadriceps (knee at 90º flexion decreased 52% immediately after eccentric exercise and recovered on the 5th day. The highest reduction of RMS occurred on the 2nd day after injury in both VL (63% and VMO (66% and only VL recovered to the pre-injury level on the 7th day. Immediately after injury, the MDF decreased by 5 and 3% (VMO and VL, respectively and recovered one day later. Serum CK levels increased by 109% on the 2nd day and were still increased by 32% on the 7th day. MRI showed large areas of injury especially in the deep region of quadriceps. In conclusion, eccentric exercise decreased the isometric torque and electromyographic signals of quadriceps muscle, which were recovered in one week, despite the muscle regeneration signals.

  19. Functional and cellular adaptations of rodent skeletal muscle to weightlessness

    Science.gov (United States)

    Caiozzo, Vincent J.; Haddad, Fadia; Baker, Michael J.; Baldwin, Kenneth M.

    1995-01-01

    This paper describes the affects of microgravity upon three key cellular levels (functional, protein, and mRNA) that are linked to one another. It is clear that at each of these levels, microgravity produces rapid and substantial alterations. One of the key challenges facing the life science community is the development of effective countermeasures that prevent the loss of muscle function as described in this paper. The development of optimal countermeasures, however, awaits a clearer understanding of events occurring at the levels of transcription, translation, and degradation.

  20. New function of the myostatin/activin type I receptor (ALK4) as a mediator of muscle atrophy and muscle regeneration.

    NARCIS (Netherlands)

    Pasteuning-Vuhman, S.; Boertje-van der Meulen, J.; van Putten, M.; Overzier, M.; ten Dijke, P; Kiełbasa, S.M.; Arindrarto, W.; Wolterbeek, R.; Lezhnina, K.V.; Ozerov, I.V.; Aliper, A.M.; Hoogaars, W.; Aartsma-Rus, A; Loomans, C.J.

    Skeletal muscle fibrosis and impaired muscle regeneration are major contributors to muscle wasting in Duchenne muscular dystrophy (DMD). Muscle growth is negatively regulated by myostatin (MSTN) and activins. Blockage of these pathways may improve muscle quality and function in DMD. Antisense

  1. Discrepancies between Skinned Single Muscle Fibres and Whole Thigh Muscle Function Characteristics in Young and Elderly Human Subjects

    Directory of Open Access Journals (Sweden)

    Hyunseok Jee

    2016-01-01

    Full Text Available We aimed to analyse the mechanical properties of skinned single muscle fibres derived from the vastus lateralis (VL muscle in relation to those of the whole intact thigh muscle and to compare any difference between young and older adults. Sixteen young men (29.25±4.65 years, 11 older men (71.45±2.94 years, 11 young women (29.64±4.88 years, and 7 older women (67.29±1.70 years were recruited. In vivo analyses were performed for mechanical properties such as isokinetic performance, isometric torque, and power. Specific force and maximum shortening velocity (Vo were measured with single muscle fibres. Sex difference showed greater impact on the functional properties of both the whole muscle (p<0.01 and single muscle fibres than aging (p<0.05. Sex difference, rather than aging, yielded more remarkable differences in gross mechanical properties in the single muscle fibre study in which significant differences between young men and young women were found only in the cross-sectional area and Vo (p<0.05. Age and sex differences reflect the mechanical properties of both single muscle fibres and whole thigh muscle, with the whole muscle yielding more prominent functional properties.

  2. Green tea extract attenuates muscle loss and improves muscle function during disuse, but fails to improve muscle recovery following unloading in aged rats

    Science.gov (United States)

    Bennett, Brian T.; Wilson, Joseph C.; Sperringer, Justin; Mohamed, Junaith S.; Edens, Neile K.; Pereira, Suzette L.

    2014-01-01

    In this study we tested the hypothesis that green tea extract (GTE) would improve muscle recovery after reloading following disuse. Aged (32 mo) Fischer 344 Brown Norway rats were randomly assigned to receive either 14 days of hindlimb suspension (HLS) or 14 days of HLS followed by normal ambulatory function for 14 days (recovery). Additional animals served as cage controls. The rats were given GTE (50 mg/kg body wt) or water (vehicle) by gavage 7 days before and throughout the experimental periods. Compared with vehicle treatment, GTE significantly attenuated the loss of hindlimb plantaris muscle mass (−24.8% vs. −10.7%, P muscle function or mass compared with vehicle treatment, animals given green tea via gavage maintained the lower losses of muscle mass that were found during HLS (−25.2% vs. −16.0%, P muscle fiber cross-sectional area loss in both plantaris (−39.9% vs. −23.9%, P muscles after HLS. This green tea-induced difference was not transient but was maintained over the reloading period for plantaris (−45.6% vs. −21.5%, P muscle fiber cross-sectional area (−38.7% vs. −10.9%, P muscles during recovery from HLS compared with vehicle-treated muscles and decreased oxidative stress and abundance of the Bcl-2-associated X protein (Bax), yet this did not further improve muscle recovery in reloaded muscles. These data suggest that muscle recovery following disuse in aging is complex. Although satellite cell proliferation and differentiation are critical for muscle repair to occur, green tea-induced changes in satellite cell number is by itself insufficient to improve muscle recovery following a period of atrophy in old rats. PMID:25414242

  3. Transoesophageal ultrasound and computer tomographic assessment of the equine cricoarytenoid dorsalis muscle: Relationship between muscle geometry and exercising laryngeal function.

    Science.gov (United States)

    Kenny, M; Cercone, M; Rawlinson, J J; Ducharme, N G; Bookbinder, L; Thompson, M; Cheetham, J

    2017-05-01

    Early detection of recurrent laryngeal neuropathy (RLN) is of considerable interest to the equine industry. To describe two imaging modalities, transoesophageal ultrasound (TEU) and computed tomography (CT) with multiplanar reconstruction to assess laryngeal muscle geometry, and determine the relationship between cricoarytenoid dorsalis (CAD) geometry and function. Two-phase study evaluating CAD geometry in experimental horses and horses with naturally occurring RLN. Equine CAD muscle volume was determined from CT scan sets using volumetric reconstruction with LiveWire. The midbody and caudal dorsal-ventral thickness of the CAD muscle was determined using a TEU in the same horses; and in horses with a range of severity of RLN (n = 112). Transoesophageal ultrasound was able to readily image the CAD muscles and lower left:right CAD thickness ratios were observed with increasing disease severity. Computed tomography based muscle volume correlated very closely with ex vivo muscle volume (R 2 = 0.77). Computed tomography reconstruction can accurately determine intrinsic laryngeal muscle geometry. A relationship between TEU measurements of CAD geometry and laryngeal function was established. These imaging techniques could be used to track the response of the CAD muscle to restorative surgical treatments such as nerve muscle pedicle graft, nerve anastomosis and functional electrical stimulation. © 2016 EVJ Ltd.

  4. Relative contribution of different muscle energy consumption processes in an energy-based muscle load sharing cost function

    NARCIS (Netherlands)

    Nikooyan, A.A.; Veeger, H.E.J.; Westerhoff, P.; Bergmann, G.; van der Helm, F.C.T.

    2013-01-01

    The aim of this study is to quantify the relative contributions of two muscle energy consumption processes (the detachment of cross-bridges and calcium-pumping) incorporated in a recently developed muscle load sharing cost function, namely the energy-based criterion, by using in vivo measured

  5. Muscle power is an important measure to detect deficits in muscle function in hip osteoarthritis

    DEFF Research Database (Denmark)

    Bieler, Theresa; Magnusson, Stig Peter; Christensen, Helle Elisabeth

    2017-01-01

    that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial for patients with hip osteoarthritis. Implications for Rehabilitation Even in patients with mild symptoms not awaiting hip replacement a generalized muscle weakening...... functional performance and leg extensor power seems to be stronger, and more strongly related to power of the symptomatic lower extremity. Our results indicate that exercise interventions focusing on improving leg extensor power of the symptomatic lower extremity and reducing asymmetry may be beneficial...

  6. Isometric muscle function of knee extensors and the relation with functional performance in patients with stroke

    NARCIS (Netherlands)

    Gerrits, K.H.L.; Beltman, M.J.; Koppe, P.A.; Konijnenbelt, H.; Elich, P.D.; de Haan, A.; Janssen, T.W.J.

    2009-01-01

    Gerrits KH, Beltman MJ, Koppe PA, Konijnenbelt H, Elich PD, de Haan A, Janssen TW. Isometric muscle function of knee extensors and the relation with functional performance in patients with stroke. Objective: (1) To examine the isometric strength, speed, and fatigue resistance of the knee extensors

  7. Muscle strength can better differentiate between gradations of functional performance than muscle quality in healthy 50-70y women.

    Science.gov (United States)

    Francis, Peter; McCormack, William; Toomey, Clodagh; Lyons, Mark; Jakeman, Philip

    It is not known which laboratory indices of muscle mass, strength or quality can distinguish functional performance in healthy middle aged women. The aim of this study was to (a) examine the association between upper leg lean tissue mass, knee extensor strength, muscle quality (strength per unit lean tissue mass) and functional performance and (b) to determine the utility of tertiles of muscle strength and muscle quality to distinguish gradations of functional capacity in healthy 50-70y women. Using a cross-sectional study design, one hundred and twenty-eight healthy 50-70y women (mean age: 60.4, SD=5.1y) underwent body composition assessment (dual X-ray absorptiometry) and performed maximal voluntary isometric contractions of the knee extensors (Con-Trex Dynamometer). Functional performance was assessed using a 5 repetition and 30s chair rise test and 900m gait speed test. Ordered by muscle strength or muscle quality, those in the highest tertile (T1) demonstrated greater functional performance than those in lowest tertile (T3). There was no association between upper leg lean tissue mass and functional performance (r=≤0.06). Muscle strength explained a greater proportion of the variance in all functional performance measures relative to muscle quality (R 2 =0.13-0.36 vs. R 2 =0.11-0.16). Upper leg lean tissue mass is not associated with physical performance in healthy 50-70y women. These results suggest strength relative to the body mass being accelerated distinguishes gradations in functional performance better than muscle quality healthy 50-70y women. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

  8. Fish axial muscle : structure-function relationships on a micro-level

    NARCIS (Netherlands)

    Spierts, I.L.Y.

    2000-01-01

    This paper discusses some examples of strong correlations between functions and structures in axial fish muscle on a micro-level. Muscle tissue needs a certain elasticity to cope with the diverse functional requirements necessary for swimming. During fast-starts of carp, muscles can be stretched up

  9. The nature of the stabilizing functions of skeletal muscles.

    Science.gov (United States)

    Kornecki, S; Zschorlich, V

    1994-02-01

    The paper defines the term coordination interval (CI), suggesting that it should replace the term electromechanical delay (EMD), if this parameter is determined in vivo for a muscle functioning in a biomechanical system with considerable mobility, but not in a kinematic pair with one degree of rotational freedom (DOF). It was adopted that CI is the time elapsing between the moment of exertion of the resultant muscular force to the surroundings by the ending of the biokinematic chain with many DOFs, and the onset of myopotential in the muscle involved in its actuation. Tested at the same time was the utility efficiency of the system: man--unstable external object with adjustable mobility, as well as the participation and coordination patterns of the upper extremity muscles engaged in stabilizing and motor activities. Twelve adult men, students of physical education, took part in the experiment. The experimental set-up was in the form of a 3.08 m long physical pendulum with the inertial moment of 574 kg m2 and with an exchangeable ending that served as a handle. Three endings were used with zero, one or two DOFs in relation to the pendulum shaft. The subjects of the test were told to push the pendulum ending with maximum force using the upper extremity, so as to impart to it the highest possible kinetic energy, irrespective of its stability type and mobility. The muscles straightening the upper extremity and stabilizing the wrist joint were tested in the EMG measurements. As a result of the experiment, it was found that (1) the utility efficiency of the organism in relation to the force and muscular power exerted on the surroundings decreases to 80 and 60%, respectively, if a driven object requires stabilization, and (2) the patterns of muscular synergism expressed by sequences and frequencies of muscular activation by the nervous system, on the grounds of CI, undergo characteristic changes if a driven object becomes unstable.

  10. Does adiposity affect muscle function during walking in children?

    Science.gov (United States)

    Lerner, Zachary F; Shultz, Sarah P; Board, Wayne J; Kung, Stacey; Browning, Raymond C

    2014-09-22

    The biomechanical mechanisms responsible for the altered gait in obese children are not well understood, particularly as they relate to increases in adipose tissue. The purpose of this study was to test the hypotheses that as body-fat percentage (BF%) increased: (1) knee flexion during stance would decrease while pelvic obliquity would increase; (2) peak muscle forces normalized to lean-weight would increase for gluteus medius, gastrocnemius, and soleus, but decrease for the vasti; and (3) the individual muscle contributions to center of mass (COM) acceleration in the direction of their primary function(s) would not change for gluteus medius, gastrocnemius, and soleus, but decrease for the vasti. We scaled a musculoskeletal model to the anthropometrics of each participant (n=14, 8-12 years old, BF%: 16-41%) and estimated individual muscle forces and their contributions to COM acceleration. BF% was correlated with average knee flexion angle during stance (r=-0.54, p=0.024) and pelvic obliquity range of motion (r=0.78, pacceleration from the vasti were negatively correlated to BF% (vertical-- r=-0.75, p=0.002, posterior-- r=-0.68, p=0.008), but there were no correlation between BF% and COM accelerations produced by the gastrocnemius, soleus and gluteus medius. Therefore, we accept our first, partially accept our second, and accept our third hypotheses. The functional demands and relative force requirements of the hip abductors during walking in pediatric obesity may contribute to altered gait kinematics. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Lower extremity nerve function, calf skeletal muscle characteristics, and functional performance in peripheral arterial disease.

    Science.gov (United States)

    Garg, Parveen K; Liu, Kiang; Ferrucci, Luigi; Guralnik, Jack M; Criqui, Michael H; Tian, Lu; Sufit, Robert; Nishida, Takashi; Tao, Huimin; Liao, Yihua; McDermott, Mary M

    2011-10-01

    To determine whether poor lower extremity nerve function is associated with less-favorable calf muscle characteristics and greater functional impairment in people with and without peripheral arterial disease (PAD). Cross-sectional. Three Chicago-area medical centers. Four hundred thirteen participants with PAD (ankle-brachial index (ABI) Calf muscle cross-sectional area and percentage fat were measured using computed tomography at 66.7% of the distance between the distal and proximal tibia. Six-minute walk performance was measured. Adjusting for age, sex, race, ABI, leg symptoms, smoking, physical activity, comorbidities, and other covariates, lower peroneal nerve conduction velocity (NCV) was associated with lower calf muscle area (first quartile 4,770.3 mm(2) , fourth quartile 5,571 mm(2) , P calf muscle area (first quartile 5,166.0 mm(2) , fourth quartile 6,003.8 mm(2) , P = .01) and poorer 6-minute walk distance (first quartile 866.4 feet, fourth quartile 1,082.5 feet, P = .01) in participants with diabetes mellitus and PAD as well. In participants without PAD, lower peroneal NCV was not associated with lower calf muscle area but was associated with poorer 6-minute walk distance only in participants without diabetes mellitus (first quartile 1,317.0 feet, fourth quartile 1,570.4 feet, P-trend calf muscle area and greater functional impairment in individuals with PAD. Future study is needed to determine whether improving peroneal NCV prevents loss of calf muscle and functional decline in people with PAD. © 2011, Copyright the Authors Journal compilation © 2011, The American Geriatrics Society.

  12. Vascular smooth muscle function: defining the diabetic vascular phenotype.

    Science.gov (United States)

    Bruno, Rosa Maria; Ghiadoni, Lorenzo

    2013-10-01

    In this issue of Diabetologia, a meta-analysis performed by Montero and co-authors (Diabetologia doi 10.1007/s00125-013-2974-1 ) demonstrates a significant impairment of vascular smooth muscle (VSM) function in type 2 diabetic patients. Endothelial function and VSM function between type 2 diabetic and healthy individuals were associated, especially in the microcirculation, confirming the hypothesis that unresponsiveness of VSM cells to NO may amplify the consequences of reduced NO availability. This study suggests a novel interpretation for endothelial dysfunction in diabetic patients, indicating VSM cells as key players. Causative mechanisms of VSM dysfunction, which seems to be a feature of the vascular phenotype of type 2 diabetes mellitus, are largely unexplored in humans. Future studies should also address the crucial issue of the prognostic significance of VSM dysfunction in diabetic patients, and possibly in other conditions characterised by high cardiovascular risk.

  13. Effect of pelvic floor muscle exercise on pelvic floor muscle activity and voiding functions during pregnancy and the postpartum period.

    Science.gov (United States)

    Kahyaoglu Sut, Hatice; Balkanli Kaplan, Petek

    2016-03-01

    The aim of this study was to investigate the effects of pelvic floor muscle exercise during pregnancy and the postpartum period on pelvic floor muscle activity and voiding functions. Pregnant women (n = 60) were randomly assigned into two groups (Training [n = 30] and Control [n = 30]) using a computer-based system. Pelvic floor muscle strength was measured using a perineometry device. Urinary symptoms were measured using the Urinary Distress Inventory (UDI-6), Incontinence Impact Questionnaire (IIQ-7), and the Overactive Bladder Questionnaire (OAB-q). Voiding functions were measured using uroflowmetry and 3-day voiding diaries. Measurements were obtained at week 28, weeks 36-38 of pregnancy, and postpartum weeks 6-8. Pelvic floor muscle strength significantly decreased during the pregnancy (P pelvic floor muscle strength improvement was significantly higher in the Training group compared to the Control group (P  0.05). However, UDI-6, coping, concern, and total scores of OAB-q were significantly decreased during weeks 36-38 of pregnancy in the Control group (P pelvic floor muscle strength, urinary symptoms, quality of life, and voiding functions. Pelvic floor muscle exercises applied during pregnancy and the postpartum period increase pelvic floor muscle strength and prevent deterioration of urinary symptoms and quality of life in pregnancy. © 2015 Wiley Periodicals, Inc.

  14. Effects of protein supplements on muscle damage, soreness and recovery of muscle function and physical performance: a systematic review.

    Science.gov (United States)

    Pasiakos, Stefan M; Lieberman, Harris R; McLellan, Tom M

    2014-05-01

    Protein supplements are frequently consumed by athletes and recreationally-active individuals, although the decision to purchase and consume protein supplements is often based on marketing claims rather than evidence-based research. To provide a systematic and comprehensive analysis of literature examining the hypothesis that protein supplements enhance recovery of muscle function and physical performance by attenuating muscle damage and soreness following a previous bout of exercise. English language articles were searched with PubMed and Google Scholar using protein and supplements together with performance, exercise, competition and muscle, alone or in combination as keywords. Inclusion criteria required studies to recruit healthy adults less than 50 years of age and to evaluate the effects of protein supplements alone or in combination with carbohydrate on performance metrics including time-to-exhaustion, time-trial or isometric or isokinetic muscle strength and markers of muscle damage and soreness. Twenty-seven articles were identified of which 18 dealt exclusively with ingestion of protein supplements to reduce muscle damage and soreness and improve recovery of muscle function following exercise, whereas the remaining 9 articles assessed muscle damage as well as performance metrics during single or repeat bouts of exercise. Papers were evaluated based on experimental design and examined for confounders that explain discrepancies between studies such as dietary control, training state of participants, sample size, direct or surrogate measures of muscle damage, and sensitivity of the performance metric. High quality and consistent data demonstrated there is no apparent relationship between recovery of muscle function and ratings of muscle soreness and surrogate markers of muscle damage when protein supplements are consumed prior to, during or after a bout of endurance or resistance exercise. There also appears to be insufficient experimental data

  15. Muscle Functional Morphology in Paleobiology: The Past, Present, and Future of "Paleomyology".

    Science.gov (United States)

    Perry, Jonathan M G; Prufrock, Kristen A

    2018-03-01

    Our knowledge of muscle anatomy and physiology in vertebrates has increased dramatically over the last two-hundred years. Today, much is understood about how muscles contract and about the functional meaning of muscular variation at multiple scales. Progress in muscle anatomy has profited from the availability of broad comparative samples, advances in microscopy have permitted comparisons at increasingly finer scales, and progress in muscle physiology has profited from many carefully designed and executed experiments. Several avenues of future work are promising. In particular, muscle ontogeny (growth and development) is poorly understood for many vertebrate groups. We consider which types of advances in muscle functional morphology are of use to paleobiologists. These are only a modest subset for muscle anatomy and a very small subset for muscle physiology. The relationship between muscle and bone - spatially and mechanically-is critical to any future advances in "paleomyology". Anat Rec, 301:538-555, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  16. Functional connectivity between core and shoulder muscles increases during isometric endurance contractions in judo competitors

    DEFF Research Database (Denmark)

    Kawczyński, Adam; Samani, Afshin; Mroczek, Dariusz

    2015-01-01

    Purpose: The aim of this study was to assess the surface electromyogram (SEMG) changes within and between muscles of the torso and shoulder region during static endurance contraction in elite judokas. We hypothesized an increased functional connectivity of muscles from the shoulder and torso...... endurance contraction consisting of bilateral arm abduction at 90°. The normalized mutual information (NMI) was computed between muscle pairs as an index indicating functional connectivity. Results: The NMIs increased significantly during endurance test for 10 of the 15 muscle pairs (P ... : We concluded that the increases in NMIs highlighted functional changes in the interplay between core and shoulder muscles during an endurance contraction in elite judokas....

  17. Relationship between muscle strength and motor function in Duchenne muscular dystrophy

    Directory of Open Access Journals (Sweden)

    Milene F. Nunes

    2016-07-01

    Full Text Available ABSTRACT Measuring muscle strength and motor function is part of Duchenne muscular dystrophy (DMD assessment. However, the relationship between these variables is controversial. Objective To investigate the relationship between muscle strength and motor function and between these variables and age. Method Muscle strength was measured by Medical Research Council (MRC scale and motor function, by Motor Function Measure (MFM, in 40 non-ambulatory patients. Spearman tests investigated the relationships between muscle strength, motor function and age. Results Total MRC and MFM scores were strongly related to each other (r = 0.94; p 0.05. Strong and moderate relationships between partial muscle strength and motor function scores were found. Higher correlation coefficients were found between total scores and Dimensions 2 (axial/ proximal control and 3 (distal control of MFM. Conclusion Muscle strength and motor function are strongly correlated and seem to decrease proportionally in DMD.

  18. Muscle fatigue in frog semitendinosus: alterations in contractile function

    Science.gov (United States)

    Thompson, L. V.; Balog, E. M.; Riley, D. A.; Fitts, R. H.

    1992-01-01

    The purpose of this study was to characterize the contractile properties of the frog semitendinosus (ST) muscle before and during recovery from fatigue, to relate the observed functional changes to alterations in specific steps in the crossbridge model of muscle contraction, and to determine how fatigue affects the force-frequency relationship. The frog ST (22 degrees C) was fatigued by direct electrical stimulation with 100-ms 150-Hz trains at 1/s for 5 min. The fatigue protocol reduced peak twitch (Pt) and tetanic (Po) force to 32 and 8.5% of initial force, respectively. The decline in Pt was less than Po, in part due to a prolongation in the isometric contraction time (CT), which increased to 300% of the initial value. The isometric twitch duration was greatly prolonged as reflected by the lengthened CT and the 800% increase in the one-half relaxation time (1/2RT). Both Pt and Po showed a biphasic recovery, a rapid initial phase (2 min) followed by a slower (40 min) return to the prefatigue force. CT and 1/2RT also recovered in two phases, returning to 160 and 265% of control in the first 5 min. CT returned to the prefatigue value between 35 and 40 min, whereas even at 60 min 1/2RT was 133% of control. The maximal velocity of shortening, determined by the slack test, was significantly reduced [from 6.7 +/- 0.5 to 2.5 +/- 0.4 optimal muscle length/s] at fatigue. The force-frequency relationship was shifted to the left, so that optimal frequency for generating Po was reduced.(ABSTRACT TRUNCATED AT 250 WORDS).

  19. An Electron Microscopic Study of the Irradiation Effects on the Striated Duct Cells of the Submandibular Gland in Rats

    International Nuclear Information System (INIS)

    Lee, Kyu Chan; Lee, Sang Rae

    1990-01-01

    study, showing a mild change in the functional morphology of the salivary striated duct cells immediately following irradiation, it is considered that the many complications which occur after radiation therapy, will disappear in time with the histological and the functional recovery of the glandular tissues.

  20. Virtual and simulated striated toolmarks for forensic applications.

    Science.gov (United States)

    Baiker, Martin; Petraco, Nicholas D K; Gambino, Carol; Pieterman, René; Shenkin, Peter; Zoon, Peter

    2016-04-01

    Large numbers of experimental toolmarks of screwdrivers are often required in casework of toolmark examiners and in research environments alike, to be able to recover the angle of attack of a crime scene mark and to determine statistically meaningful properties of toolmarks respectively. However, in practice the number of marks is limited by the time needed to create them. In this article, we present an approach to predict how a striated mark of a particular tool would look like, using 3D surface datasets of screwdrivers. We compare these virtual toolmarks qualitatively and quantitatively with real experimental marks in wax and show that they are very similar. In addition we study toolmark similarity, dependent on the angle of attack, with a very high angular resolution of 1°. The results show that for the tested type of screwdriver, our toolmark comparison framework yields known match similarity scores that are above the mean known non-match similarity scores, even for known match differences in angle of attack of up to 40°. In addition we demonstrate an approach to automatically recover the angle of attack of an experimental toolmark and experiments yield high accuracy and precision of 0.618 ± 4.179°. Furthermore, we present a strategy to study the structural elements of striated toolmarks using wavelet analysis, and show how to use the results to simulate realistic toolmarks. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Sensory nerve cross-anastomosis and electrical muscle stimulation synergistically enhance functional recovery of chronically denervated muscle.

    Science.gov (United States)

    Willand, Michael P; Holmes, Michael; Bain, James R; de Bruin, Hubert; Fahnestock, Margaret

    2014-11-01

    Long-term muscle denervation leads to severe and irreversible atrophy coupled with loss of force and motor function. These factors contribute to poor functional recovery following delayed reinnervation. The authors' previous work demonstrated that temporarily suturing a sensory nerve to the distal motor stump (called sensory protection) significantly reduces muscle atrophy and improves function following reinnervation. The authors have also shown that 1 month of electrical stimulation of denervated muscle significantly improves function and reduces atrophy. In this study, the authors tested whether a combination of sensory protection and electrical stimulation would enhance functional recovery more than either treatment alone. Rat gastrocnemius muscles were denervated by cutting the tibial nerve. The peroneal nerve was then sutured to the distal tibial stump following 3 months of treatment (i.e., electrical stimulation, sensory protection, or both). Three months after peroneal repair, functional and histologic measurements were taken. All treatment groups had significantly higher muscle weight (pstimulation or sensory protection alone. The combined treatment also produced motor unit counts significantly greater than sensory protection alone (p<0.05). The combination treatment synergistically reduces atrophy and improves reinnervation and functional measures following delayed nerve repair, suggesting that these approaches work through different mechanisms. The authors' research supports the clinical use of both modalities together following peripheral nerve injury.

  2. Functional electrical stimulation to the abdominal wall muscles synchronized with the expiratory flow does not induce muscle fatigue.

    Science.gov (United States)

    Okuno, Yukako; Takahashi, Ryoichi; Sewa, Yoko; Ohse, Hirotaka; Imura, Shigeyuki; Tomita, Kazuhide

    2017-03-01

    [Purpose] Continuous electrical stimulation of abdominal wall muscles is known to induce mild muscle fatigue. However, it is not clear whether this is also true for functional electrical stimulation delivered only during the expiratory phase of breathing. This study aimed to examine whether or not intermittent electrical stimulation delivered to abdominal wall muscles induces muscle fatigue. [Subjects and Methods] The subjects were nine healthy adults. Abdominal electrical stimulation was applied for 1.5 seconds from the start of expiration and then turned off during inspiration. The electrodes were attached to both sides of the abdomen at the lower margin of the 12th rib. Abdominal electrical stimulation was delivered for 15 minutes with the subject in a seated position. Expiratory flow was measured during stimulus. Trunk flexor torque and electromyography activity were measured to evaluate abdominal muscle fatigue. [Results] The mean stimulation on/off ratio was 1:2.3. The declining rate of abdominal muscle torque was 61.1 ± 19.1% before stimulus and 56.5 ± 20.9% after stimulus, not significantly different. The declining rate of mean power frequency was 47.8 ± 11.7% before stimulus and 47.9 ± 10.2% after stimulus, not significantly different. [Conclusion] It was found that intermittent electrical stimulation to abdominal muscles synchronized with the expiratory would not induce muscle fatigue.

  3. Correlation between adolescents low back pain, trunk muscle functions and physical activity

    OpenAIRE

    Tuzikaitė, Gintarė

    2016-01-01

    Correlation Between Adolescents Low Back Pain, Trunk Muscle Functions and Physical Activity The aim of research work: The aim of this study was to evaluate the relationship between adolescents low back pain, trunk muscle functions and physical activity. Tasks of work: 1. To assess and compare the lumbar proprioception in subjects with and without low back pain. 2. To assess and compare the trunk muscle functions in subjects with and without low back pain. 3. To assess and compare the physical...

  4. Free function muscle transfers for upper extremity reconstruction: a review of indications, techniques, and outcomes.

    Science.gov (United States)

    Fischer, John P; Elliott, River M; Kozin, Scott H; Levin, L Scott

    2013-12-01

    Free functional muscle transfer (FFMT) replaces destroyed, denervated, or resected skeletal muscle units in the upper extremity with functioning skeletal muscle from other locations in the body. Common indications for FFMT include brachial plexus injuries, ischemic contracture, tumor resection, and extensive direct muscle trauma. Recent studies have focused on improving patient outcomes through refinements in muscle flap harvest and inset, donor nerve selection, and postoperative management. In this review, we assess and summarize the current literature on FFMT, with emphasis on etiopathogenesis, diagnosis, treatment, postoperative management, and clinical outcomes. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  5. Mechanical muscle function, morphology, and fiber type in lifelong trained elderly

    DEFF Research Database (Denmark)

    Aagaard, Per; Magnusson, Peter S; Larsson, Benny

    2007-01-01

    PURPOSE: Maximal muscle contraction force and muscle mass are both reduced during the natural aging process. Long-term training may be used to attenuate this age-related loss in muscle function and muscle size. METHODS: Maximum isometric quadriceps strength (MVC), rate of force development (RFD...... (i.e., lifelong) strength training. This relative preservation in muscle morphology and function may provide an important physical reserve capacity to retain muscle mass and function above the critical threshold for independent living at old age.......), and muscle fiber composition and size (CSA) were studied in elderly individuals (68-78 yr) chronically exposed (> 50 yr) to either endurance (E) or strength (S) training, and in age-matched, untrained (U) elderly group. RESULTS: E and S showed greater MVC than did U. Contractile RFD was elevated in S...

  6. Systemic Inflammation in Duchenne Muscular Dystrophy: Association with Muscle Function and Nutritional Status

    Science.gov (United States)

    Cruz-Guzmán, Oriana del Rocío; Rodríguez-Cruz, Maricela; Escobar Cedillo, Rosa Elena

    2015-01-01

    Inflammation described in patients with Duchenne muscular dystrophy (DMD) may be related to loss of muscle function or to obesity. It is unknown if circulating proinflammatory cytokines (IL-6, IL-1, and TNF-α) levels are associated with muscle function. The purpose was to evaluate whether an association exists between systemic inflammation with muscle function and nutritional status in DMD patients. In 66 DMD patients without corticosteroid treatment, the following were evaluated in serum: cytokines (IL-1, IL-6, and TNF-α), C-reactive protein (CRP), leptin, adiponectin, and creatine kinase (CK). Muscle function was evaluated using Vignos Scale. Patients with better muscle function had the highest concentration of CK, IL-1, and TNF-α compared with less muscle function. No differences in IL-6 and adiponectin concentration were identified among groups with different levels of muscle function. Also, no differences were observed in the concentration of cytokines among groups with different nutritional status levels (underweight, normal weight, and overweight/obese). However, CRP and leptin were increased in the obese group compared with normal and underweight subjects. Systemic inflammation is increased in patients with better muscle function and decreases in DMD patients with poorer muscle function; nevertheless, systemic inflammation is similar among different levels of nutritional status in DMD patients. PMID:26380303

  7. Systemic Inflammation in Duchenne Muscular Dystrophy: Association with Muscle Function and Nutritional Status

    Directory of Open Access Journals (Sweden)

    Oriana del Rocío Cruz-Guzmán

    2015-01-01

    Full Text Available Inflammation described in patients with Duchenne muscular dystrophy (DMD may be related to loss of muscle function or to obesity. It is unknown if circulating proinflammatory cytokines (IL-6, IL-1, and TNF-α levels are associated with muscle function. The purpose was to evaluate whether an association exists between systemic inflammation with muscle function and nutritional status in DMD patients. In 66 DMD patients without corticosteroid treatment, the following were evaluated in serum: cytokines (IL-1, IL-6, and TNF-α, C-reactive protein (CRP, leptin, adiponectin, and creatine kinase (CK. Muscle function was evaluated using Vignos Scale. Patients with better muscle function had the highest concentration of CK, IL-1, and TNF-α compared with less muscle function. No differences in IL-6 and adiponectin concentration were identified among groups with different levels of muscle function. Also, no differences were observed in the concentration of cytokines among groups with different nutritional status levels (underweight, normal weight, and overweight/obese. However, CRP and leptin were increased in the obese group compared with normal and underweight subjects. Systemic inflammation is increased in patients with better muscle function and decreases in DMD patients with poorer muscle function; nevertheless, systemic inflammation is similar among different levels of nutritional status in DMD patients.

  8. Synergistic Activities of Abdominal Muscles Are Required for Efficient Micturition in Anesthetized Female Mice.

    Science.gov (United States)

    Zhang, Chuan; Zhang, Yingchun; Cruz, Yolanda; Boone, Timothy B; Munoz, Alvaro

    2018-03-01

    To characterize the electromyographic activity of abdominal striated muscles during micturition in urethane-anesthetized female mice, and to quantitatively evaluate the contribution of abdominal responses to efficient voiding. Cystometric and multichannel electromyographic recordings were integrated to enable a comprehensive evaluation during micturition in urethane-anesthetized female mice. Four major abdominal muscle domains were evaluated: the external oblique, internal oblique, and superior and inferior rectus abdominis. To further characterize the functionality of the abdominal muscles, pancuronium bromide (25 μg/mL or 50 μg/mL, abdominal surface) was applied as a blocking agent of neuromuscular junctions. We observed a robust activation of the abdominal muscles during voiding, with a consistent onset/offset concomitant with the bladder pressure threshold. Pancuronium was effective, in a dose-dependent fashion, for partial and complete blockage of abdominal activity. Electromyographic discharges during voiding were significantly inhibited by applying pancuronium. Decreased cystometric parameters were recorded, including the peak pressure, pressure threshold, intercontractile interval, and voiding duration, suggesting that the voiding efficiency was significantly compromised by abdominal muscle relaxation. The relevance of the abdominal striated musculature for micturition has remained a topic of debate in human physiology. Although the study was performed on anesthetized mice, these results support the existence of synergistic abdominal electromyographic activity facilitating voiding in anesthetized mice. Further, our study presents a rodent model that can be used for future investigations into micturition-related abdominal activity.

  9. Validity of Estimation of Pelvic Floor Muscle Activity from Transperineal Ultrasound Imaging in Men.

    Science.gov (United States)

    Stafford, Ryan E; Coughlin, Geoff; Lutton, Nicholas J; Hodges, Paul W

    2015-01-01

    To investigate the relationship between displacement of pelvic floor landmarks observed with transperineal ultrasound imaging and electromyography of the muscles hypothesised to cause the displacements. Three healthy men participated in this study, which included ultrasound imaging of the mid-urethra, urethra-vesical junction, ano-rectal junction and bulb of the penis. Fine-wire electromyography electrodes were inserted into the puborectalis and bulbocavernosus muscles and a transurethral catheter electrode recorded striated urethral sphincter electromyography. A nasogastric sensor recorded intra-abdominal pressure. Tasks included submaximal and maximal voluntary contractions, and Valsalva. The relationship between each of the parameters measured from ultrasound images and electromyography or intra-abdominal pressure amplitudes was described with nonlinear regression. Strong, non-linear relationships were calculated for each predicted landmark/muscle pair for submaximal contractions (R2-0.87-0.95). The relationships between mid-urethral displacement and striated urethral sphincter electromyography, and bulb of the penis displacement and bulbocavernosus electromyography were strong during maximal contractions (R2-0.74-0.88). Increased intra-abdominal pressure prevented shortening of puborectalis, which resulted in weak relationships between electromyography and anorectal and urethravesical junction displacement during all tasks. Displacement of landmarks in transperineal ultrasound imaging provides meaningful measures of activation of individual pelvic floor muscles in men during voluntary contractions. This method may aid assessment of muscle function or feedback for training.

  10. Validity of Estimation of Pelvic Floor Muscle Activity from Transperineal Ultrasound Imaging in Men.

    Directory of Open Access Journals (Sweden)

    Ryan E Stafford

    Full Text Available To investigate the relationship between displacement of pelvic floor landmarks observed with transperineal ultrasound imaging and electromyography of the muscles hypothesised to cause the displacements.Three healthy men participated in this study, which included ultrasound imaging of the mid-urethra, urethra-vesical junction, ano-rectal junction and bulb of the penis. Fine-wire electromyography electrodes were inserted into the puborectalis and bulbocavernosus muscles and a transurethral catheter electrode recorded striated urethral sphincter electromyography. A nasogastric sensor recorded intra-abdominal pressure. Tasks included submaximal and maximal voluntary contractions, and Valsalva. The relationship between each of the parameters measured from ultrasound images and electromyography or intra-abdominal pressure amplitudes was described with nonlinear regression.Strong, non-linear relationships were calculated for each predicted landmark/muscle pair for submaximal contractions (R2-0.87-0.95. The relationships between mid-urethral displacement and striated urethral sphincter electromyography, and bulb of the penis displacement and bulbocavernosus electromyography were strong during maximal contractions (R2-0.74-0.88. Increased intra-abdominal pressure prevented shortening of puborectalis, which resulted in weak relationships between electromyography and anorectal and urethravesical junction displacement during all tasks.Displacement of landmarks in transperineal ultrasound imaging provides meaningful measures of activation of individual pelvic floor muscles in men during voluntary contractions. This method may aid assessment of muscle function or feedback for training.

  11. Muscle strength can better differentiate between gradations of functional performance than muscle quality in healthy 50–70 y women

    OpenAIRE

    Francis, Peter; McCormack, William; Toomey, Clodagh; Lyons, Mark; Jakeman, Philip

    2017-01-01

    Objective It is not known which laboratory indices of muscle mass, strength or quality can distinguish functional performance in healthy middle aged women. The aim of this study was to (a) examine the association between upper leg lean tissue mass, knee extensor strength, muscle quality (strength per unit lean tissue mass) and functional performance and (b) to determine the utility of tertiles of muscle strength and muscle quality to distinguish gradations of functional capacity in healthy 50...

  12. Engineered matrices for skeletal muscle satellite cell engraftment and function.

    Science.gov (United States)

    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.

  13. Systemic down-regulation of delta-9 desaturase promotes muscle oxidative metabolism and accelerates muscle function recovery following nerve injury.

    Directory of Open Access Journals (Sweden)

    Ghulam Hussain

    Full Text Available The progressive deterioration of the neuromuscular axis is typically observed in degenerative conditions of the lower motor neurons, such as amyotrophic lateral sclerosis (ALS. Neurodegeneration in this disease is associated with systemic metabolic perturbations, including hypermetabolism and dyslipidemia. Our previous gene profiling studies on ALS muscle revealed down-regulation of delta-9 desaturase, or SCD1, which is the rate-limiting enzyme in the synthesis of monounsaturated fatty acids. Interestingly, knocking out SCD1 gene is known to induce hypermetabolism and stimulate fatty acid beta-oxidation. Here we investigated whether SCD1 deficiency can affect muscle function and its restoration in response to injury. The genetic ablation of SCD1 was not detrimental per se to muscle function. On the contrary, muscles in SCD1 knockout mice shifted toward a more oxidative metabolism, and enhanced the expression of synaptic genes. Repressing SCD1 expression or reducing SCD-dependent enzymatic activity accelerated the recovery of muscle function after inducing sciatic nerve crush. Overall, these findings provide evidence for a new role of SCD1 in modulating the restorative potential of skeletal muscles.

  14. Resistance training induces qualitative changes in muscle morphology, muscle architecture, and muscle function in elderly postoperative patients

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Andersen, Jesper L; Dalgas, Ulrik

    2008-01-01

    Although the negative effects of bed rest on muscle strength and muscle mass are well established, it still remains a challenge to identify effective methods to restore physical capacity of elderly patients recovering from hospitalization. The present study compared different training regimes...... degrees /s (P thickness increased by 15% (P

  15. Respiratory Muscle Training and Cognitive Function Exercising at Altitude.

    Science.gov (United States)

    Quackenbush, Joseph; Duquin, Aubrey; Helfer, Samuel; Pendergast, David R

    2016-01-01

    Hiking and trekking often occur at altitudes up to 12,000 ft altitude. The hypoxia-induced hyperventilation at altitude paradoxically reduces arterial CO2 (Paco2). A reduction in Paco2 results in vasoconstriction of the blood vessels of the brain and thus in local hypoxia. The local hypoxia likely affects cognitive function, which may result in reduced performance and altitude accidents. Recent publications have demonstrated that voluntary isocapnic hyperventilatory training of the respiratory muscles (VIHT) can markedly enhance exercise endurance as it is associated with reduced ventilation and its energy cost. VIHT may be useful in blunting the altitude-induced hyperventilation leading to higher Paco2 and improved cognitive function. This study examined the effects of VIHT, compared to control (C) and placebo (PVIHT) groups, on selected measures of executive functioning, including working memory and processing speed (i.e., Stroop Test, Symbol Digit Modalities Test, and Digit Span Forward) at simulated altitude up to 12,000 ft. Associated physiological parameters were also measured. The Digit Span Forward Test did not show improvements after VIHT in any group. The VIHT group, but not C or PVIHT groups, improved significantly (17-30%) on the Stroop Test. Similarly the VIHT group, but not the C and PVIHT groups, improved correct responses (26%) and number of attempts (24%) on the Symbol Digit Modalities Test. In addition, reaction time was also improved (16%). VIHT improved processing speed and working memory during exercise at altitude.

  16. The Popeye domain containing 2 (popdc2) gene in zebrafish is required for heart and skeletal muscle development

    Science.gov (United States)

    Kirchmaier, Bettina C.; Poon, Kar Lai; Schwerte, Thorsten; Huisken, Jan; Winkler, Christoph; Jungblut, Benno; Stainier, Didier Y.; Brand, Thomas

    2013-01-01

    The Popeye domain containing (Popdc) genes encode a family of transmembrane proteins with an evolutionary conserved Popeye domain. These genes are abundantly expressed in striated muscle tissue, however their function is not well understood. In this study we have investigated the role of the popdc2 gene in zebrafish. Popdc2 transcripts were detected in the embryonic myocardium and transiently in the craniofacial and tail musculature. Morpholino oligonucleotide-mediated knockdown of popdc2 resulted in aberrant development of skeletal muscle and heart. Muscle segments in the trunk were irregularly shaped and craniofacial muscles were severely reduced or even missing. In the heart, pericardial edema was prevalent in the morphants and heart chambers were elongated and looping was abnormal. These pathologies in muscle and heart were alleviated after reducing the morpholino concentration. However the heart still was abnormal displaying cardiac arrhythmia at later stages of development. Optical recordings of cardiac contractility revealed irregular ventricular contractions with a 2:1, or 3:1 atrial/ventricular conduction ratio, which caused a significant reduction in heart frequency. Recordings of calcium transients with high spatiotemporal resolution using a transgenic calcium indicator line (Tg(cmlc2:gCaMP)s878) and SPIM microscopy confirmed the presence of a severe arrhythmia phenotype. Our results identify popdc2 as a gene important for striated muscle differentiation and cardiac morphogenesis. In addition it is required for the development of the cardiac conduction system. PMID:22290329

  17. Catalase overexpression does not impair extensor digitorum longus muscle function in normal mice.

    Science.gov (United States)

    Liu, Mingju; Yue, Yongping; Li, Dejia; Duan, Dongsheng

    2007-12-01

    Catalase is a major antioxidant enzyme. Increasing catalase expression represents a promising avenue to improve muscle function in certain physiological conditions and in some muscle diseases. We hypothesized that catalase overexpression should not impair normal muscle contraction. We delivered a hemagglutinin (HA)-tagged human catalase gene to normal mouse muscle by an adeno-associated viral vector (AAV). Western blot and immunostaining revealed efficient expression of HA-tagged catalase. Enzymatic assay demonstrated an approximately threefold increase in catalase activity in AAV-infected muscles. Catalase overexpression impaired neither twitch nor tetanic tension in the extensor digitorum longus (EDL) muscle. Furthermore, EDL fatigue response was not altered. Taken together, we have developed a novel AAV vector to enhance catalase expression. Lack of apparent toxicity in normal muscle strongly supports further exploration of this vector to reduce oxidative stress-induced muscle damage.

  18. Functional heterogeneity of side population cells in skeletal muscle

    International Nuclear Information System (INIS)

    Uezumi, Akiyoshi; Ojima, Koichi; Fukada, So-ichiro; Ikemoto, Madoka; Masuda, Satoru; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi

    2006-01-01

    Skeletal muscle regeneration has been exclusively attributed to myogenic precursors, satellite cells. A stem cell-rich fraction referred to as side population (SP) cells also resides in skeletal muscle, but its roles in muscle regeneration remain unclear. We found that muscle SP cells could be subdivided into three sub-fractions using CD31 and CD45 markers. The majority of SP cells in normal non-regenerating muscle expressed CD31 and had endothelial characteristics. However, CD31 - CD45 - SP cells, which are a minor subpopulation in normal muscle, actively proliferated upon muscle injury and expressed not only several regulatory genes for muscle regeneration but also some mesenchymal lineage markers. CD31 - CD45 - SP cells showed the greatest myogenic potential among three SP sub-fractions, but indeed revealed mesenchymal potentials in vitro. These SP cells preferentially differentiated into myofibers after intramuscular transplantation in vivo. Our results revealed the heterogeneity of muscle SP cells and suggest that CD31 - CD45 - SP cells participate in muscle regeneration

  19. Shoulder muscle activity and function in common shoulder rehabilitation exercises.

    Science.gov (United States)

    Escamilla, Rafael F; Yamashiro, Kyle; Paulos, Lonnie; Andrews, James R

    2009-01-01

    The rotator cuff performs multiple functions during shoulder exercises, including glenohumeral abduction, external rotation (ER) and internal rotation (IR). The rotator cuff also stabilizes the glenohumeral joint and controls humeral head translations. The infraspinatus and subscapularis have significant roles in scapular plane abduction (scaption), generating forces that are two to three times greater than supraspinatus force. However, the supraspinatus still remains a more effective shoulder abductor because of its more effective moment arm. Both the deltoids and rotator cuff provide significant abduction torque, with an estimated contribution up to 35-65% by the middle deltoid, 30% by the subscapularis, 25% by the supraspinatus, 10% by the infraspinatus and 2% by the anterior deltoid. During abduction, middle deltoid force has been estimated to be 434 N, followed by 323 N from the anterior deltoid, 283 N from the subscapularis, 205 N from the infraspinatus, and 117 N from the supraspinatus. These forces are generated not only to abduct the shoulder but also to stabilize the joint and neutralize the antagonistic effects of undesirable actions. Relatively high force from the rotator cuff not only helps abduct the shoulder but also neutralizes the superior directed force generated by the deltoids at lower abduction angles. Even though anterior deltoid force is relatively high, its ability to abduct the shoulder is low due to a very small moment arm, especially at low abduction angles. The deltoids are more effective abductors at higher abduction angles while the rotator cuff muscles are more effective abductors at lower abduction angles. During maximum humeral elevation the scapula normally upwardly rotates 45-55 degrees, posterior tilts 20-40 degrees and externally rotates 15-35 degrees. The scapular muscles are important during humeral elevation because they cause these motions, especially the serratus anterior, which contributes to scapular upward rotation

  20. Use It or Lose It: Skeletal Muscle Function and Performance Results from Space Shuttle

    Science.gov (United States)

    Ryder, Jeffrey

    2011-01-01

    The Space Shuttle Program provided a wealth of valuable information regarding the adaptations of skeletal muscle to weightlessness. Studies conducted during the Extended Duration Orbiter Medical Project (EDOMP) represented ground breaking work on the effects of spaceflight on muscle form and function from applied human research to cellular adaptations. Results from detailed supplementary objective (DSO) 477 demonstrated that muscle strength losses could occur rapidly in response to short-duration spaceflight. The effects of spaceflight-induced unloading were primarily restricted to postural muscles such as those of the back as well as the knee extensors. DSO 606 provided evidence from MRI that the observed strength losses were partially accounted for by a reduction in the size of the individual muscles. Muscle biopsy studies conducted during DSO 475 were able to show muscle atrophy in individual muscle fibers from the quadriceps muscles. Reduced quadriceps muscle size and strength was also observed during the 17-d Life and Microgravity Spacelab mission aboard STS-78. Multiple maximal strength tests were conducted in flight on the calf muscles and it has been hypothesized that these high force contractions may have acted as a countermeasure. Muscle fiber mechanics were studied on calf muscle samples pre- and postflight. While some responses were crewmember specific, the general trend was that muscle fiber force production dropped and shortening velocity increased. The increased shortening velocity helped to maintain muscle fiber power. Numerous rodent studies performed during Shuttle missions suggest that many of the effects reported in Shuttle crewmembers could be due to lesions in the cellular signaling pathways that stimulate protein synthesis as well as an increase in the mechanisms that up-regulate protein breakdown. The results have important implications regarding the overall health and performance capabilities of future crewmembers that will venture beyond

  1. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures.

    Science.gov (United States)

    Sohn, M Hongchul; Ting, Lena H

    2016-01-01

    We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., synergy force vector was reduced by ~45% when generalizability requirements were imposed. Muscles recruited in the generalizable muscle activation patterns had less sensitive torque-producing characteristics to changes in postures. We

  2. The contribution of inspiratory muscles function to exercise limitation in heart failure: pathophysiological mechanisms

    OpenAIRE

    Ribeiro,Jorge P.; Chiappa,Gaspar R.; Callegaro,Carine C.

    2012-01-01

    BACKGROUND: Heart failure induces histological, metabolic and functional adaptations in the inspiratory muscles. This inspiratory muscle weakness, which occurs in 30% to 50% of the heart failure patients, is associated with reduction in the functional capacity, reduction in the quality of life and with a poor prognosis in these individuals. OBJECTIVES: The objective of this review was to discuss the pathophysiological mechanisms that may explain the role of the inspiratory muscles in the exer...

  3. Volumetric Muscle Loss: Persistent Functional Deficits Beyond Frank Loss of Tissue

    Science.gov (United States)

    2014-09-18

    testing system.5 Peak TA muscle isometric torque was determined with the ankle at a right angle 0˚ and 20˚ of dorsi- or plantar flexion, assuming a moment...Assessment TA muscles with VML (with or without Osteotomy) exhibited persistent and statistically similar maximal isometric tetanic torque deficits at 4...only groups presented TA muscle torque deficits in the involved leg. Moreover, functional deficits after VML were not PERSISTENT FUNCTIONAL DEFICITS

  4. Study of the striated nature of a glow discharge

    International Nuclear Information System (INIS)

    Hernandez A, M.

    1995-01-01

    In an investigation in progress here, plasma diagnostics and detection of standing and moving striations is being made in a discharge in Argon at pressures of 2 x 10 -1 to 9 x 10 -1 mb and currents of 2 to 9 m-amp inside an discharge tube. Measurement of the temperature of the electrons, the concentration of electrons and the plasma potential are obtained in different places of the discharge by the double probe method, together with the computation system reported in [1]. In similar way an experimental work of the striated column in a discharge plasma to find the regimen of appearance of the standing and moving striations show some properties of moving striations (frequency and velocity) and standing striations. Two different oscilations are observed in motion in contrary directions along the discharge tube with a photomultiplier. (Author)

  5. Alpha-actinin in different invertebrate muscle cell types of Drosophila melanogaster, the earthworm Eisenia foetida, and the snail Helix aspersa.

    Science.gov (United States)

    Royuela, M; Astier, C; Fraile, B; Paniagua, R

    1999-01-01

    The presence and distribution of alpha-actinin has been studied in several invertebrate muscle cell types. These comprised transversely striated muscle (flight muscle) from the fruit fly Drosophila melanogaster, transversely striated muscle (heart muscle) from the snail Helix aspersa, obliquely striated muscle (body wall muscle) from the earthworm Eisenia foetida, smooth muscle (retractor muscle) from H. aspersa, and smooth muscle (outer muscular layer of the pseudoheart) from E. foetida. The study was carried by means of Western blot analysis, ELISA, and immunohistochemical electron microscopy, using anti alpha-actinin antibody. Immunoreaction for a protein with the same molecular weight as that of mammalian alpha-actinin was detected in all muscle types studied, although the amount and intensity of immunoreaction varied among them. In the insect muscle, immunolabelling was found along the whole Z-line. In both the transversely striated muscle from the snail and the obliquely striated muscle from the earthworm, immunolabelling did not occupy the whole Z-line but showed discontinuous, orderly arranged patches along the Z-line course. In the two smooth muscles studied (snail and earthworm), immunolabelling was limited to small patches which did not show an apparently ordered distribution. Since it is assumed that alpha-actinin is located at the anchorage sites for actin filaments, present observations suggest that, only in the Drosophila muscle, actin filaments are parallelly arranged in all their course, whereas in the other invertebrate muscles studied these filaments converge on discontinuously distributed anchorage sites.

  6. The relationship between two different mechanical cost functions and muscle oxygen consumption.

    Science.gov (United States)

    Praagman, M; Chadwick, E K J; van der Helm, F C T; Veeger, H E J

    2006-01-01

    Inverse-dynamic models often use cost functions to solve the load-sharing problem. Although it is often assumed that energy is minimised, most cost functions are based on mechanically related measures like muscle force or stress. The aim of this study was to analyse the relationships of two cost functions with experimentally determined data on muscle energy consumption. Four subjects performed isometric contractions generating combinations of elbow flexion/extension and pro/supination moments. Muscle oxygen consumption (VO2) of the m. biceps breve, m. biceps longum, m. brachioradialis and m. triceps laterale was measured with near infrared spectroscopy. Both cost functions were implemented into an existing inverse-dynamic shoulder and elbow model and the individual cost values per muscle were calculated, normalised and subsequently compared to experimental VO2 values. The minimum stress cost function led to a good correspondence between VO2 and cost for the m. triceps laterale but for the flexor muscles cost was significantly lower. A newly proposed energy-related cost function showed, however, a far better correspondence. The inclusion of a linear term and muscle mass in the new criterion led model results to correspond better to experimental results. The energy-related cost function appeared to be a better measure for muscle energy consumption than the stress cost function and led to more realistic predictions of muscle activation.

  7. Relationships of Muscle Function and Subjective Knee Function in Patients After ACL Reconstruction.

    Science.gov (United States)

    Bodkin, Stephan; Goetschius, John; Hertel, Jay; Hart, Joe

    2017-07-01

    After anterior cruciate ligament reconstruction (ACLR), relationships between objective measures of muscle function and patient-reported outcomes may change over time. Examining these measures at different time frames after surgery may help develop individualized approaches to improve post-ALCR analysis. To examine the associations between subjective knee function and lower-extremity muscle function in individual patients at various time points after ACLR. Descriptive laboratory study. Fifty-one participants who underwent primary, unilateral ACLR (15 males, 36 females; mean age, 22.9 ± 4.5 years; mean height, 172.4 ± 10.1 cm; mean weight, 68.7 ± 13.1 kg) were separated into 3 groups depending on time since surgery (early, 5 years). Subjective knee function was quantified using the International Knee Documentation Committee (IKDC) subjective knee form and the Knee injury and Osteoarthritis Outcome Score (KOOS). Isometric knee extension and flexion strength were collected at 90 deg/s. Single-leg hop performance was measured using the single hop, triple hop, cross-over hop, and 6-m timed hop. Coefficient correlations were calculated between subjective knee function and objective measures of muscle function for each group. The early group demonstrated moderate correlations between the KOOS and unilateral measures of flexion peak torque ( r = 0.514, P = .035) and flexion power ( r = 0.54, P = .027). The middle group demonstrated the strongest correlations between the KOOS and symmetry measures of the single hop ( r = 0.69, P = .002) and extension work ( r = 0.71, P = .002) as well as unilateral measures of the triple hop ( r = 0.52, P = .034) and extension work ( r = 0.66, P = .004). The late group demonstrated strong correlations between the 6-m timed hop symmetry and the IKDC ( r = 0.716, P = .001) and KOOS ( r = 0.71, P = .001). Patients with a post-ACLR status of less than 2 years exhibited stronger relationships with unilateral strength measures to subjective

  8. Identification and functional clustering of genes regulating muscle protein degradation from amongst the known C. elegans muscle mutants.

    Directory of Open Access Journals (Sweden)

    Freya Shephard

    Full Text Available Loss of muscle mass via protein degradation is an important clinical problem but we know little of how muscle protein degradation is regulated genetically. To gain insight our labs developed C. elegans into a model for understanding the regulation of muscle protein degradation. Past studies uncovered novel functional roles for genes affecting muscle and/or involved in signalling in other cells or tissues. Here we examine most of the genes previously identified as the sites of mutations affecting muscle for novel roles in regulating degradation. We evaluate genomic (RNAi knockdown approaches and combine them with our established genetic (mutant and pharmacologic (drugs approaches to examine these 159 genes. We find that RNAi usually recapitulates both organismal and sub-cellular mutant phenotypes but RNAi, unlike mutants, can frequently be used acutely to study gene function solely in differentiated muscle. In the majority of cases where RNAi does not produce organismal level phenotypes, sub-cellular defects can be detected; disrupted proteostasis is most commonly observed. We identify 48 genes in which mutation or RNAi knockdown causes excessive protein degradation; myofibrillar and/or mitochondrial morphologies are also disrupted in 19 of these 48 cases. These 48 genes appear to act via at least three sub-networks to control bulk degradation of protein in muscle cytosol. Attachment to the extracellular matrix regulates degradation via unidentified proteases and affects myofibrillar and mitochondrial morphology. Growth factor imbalance and calcium overload promote lysosome based degradation whereas calcium deficit promotes proteasome based degradation, in both cases myofibrillar and mitochondrial morphologies are largely unaffected. Our results provide a framework for effectively using RNAi to identify and functionally cluster novel regulators of degradation. This clustering allows prioritization of candidate genes/pathways for future

  9. Muscle biopsies from human muscle diseases with myopathic pathology reveal common alterations in mitochondrial function.

    Science.gov (United States)

    Sunitha, Balaraju; Gayathri, Narayanappa; Kumar, Manish; Keshava Prasad, Thottethodi Subrahmanya; Nalini, Atchayaram; Padmanabhan, Balasundaram; Srinivas Bharath, Muchukunte Mukunda

    2016-07-01

    Muscle diseases are clinically and genetically heterogeneous and manifest as dystrophic, inflammatory and myopathic pathologies, among others. Our previous study on the cardiotoxin mouse model of myodegeneration and inflammation linked muscle pathology with mitochondrial damage and oxidative stress. In this study, we investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies from muscle disease patients, represented by dysferlinopathy (dysfy) (dystrophic pathology; n = 43), polymyositis (PM) (inflammatory pathology; n = 24), and distal myopathy with rimmed vacuoles (DMRV) (distal myopathy; n = 31) were analyzed. Mitochondrial damage (ragged blue and COX-deficient fibers) was revealed in dysfy, PM, and DMRV cases by enzyme histochemistry (SDH and COX-SDH), electron microscopy (vacuolation and altered cristae) and biochemical assays (significantly increased ADP/ATP ratio). Proteomic analysis of muscle mitochondria from all three muscle diseases by isobaric tag for relative and absolute quantitation labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated down-regulation of electron transport chain (ETC) complex subunits, assembly factors and Krebs cycle enzymes. Interestingly, 80 of the under-expressed proteins were common among the three pathologies. Assay of ETC and Krebs cycle enzyme activities validated the MS data. Mitochondrial proteins from muscle pathologies also displayed higher tryptophan (Trp) oxidation and the same was corroborated in the cardiotoxin model. Molecular modeling predicted Trp oxidation to alter the local structure of mitochondrial proteins. Our data highlight mitochondrial alterations in muscle pathologies, represented by morphological changes, altered mitochondrial proteome and protein oxidation, thereby establishing the role of mitochondrial damage in human muscle diseases. We investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies

  10. Contribution of elastic tissues to the mechanics and energetics of muscle function during movement.

    Science.gov (United States)

    Roberts, Thomas J

    2016-01-01

    Muscle force production occurs within an environment of tissues that exhibit spring-like behavior, and this elasticity is a critical determinant of muscle performance during locomotion. Muscle force and power output both depend on the speed of contraction, as described by the isotonic force-velocity curve. By influencing the speed of contractile elements, elastic structures can have a profound effect on muscle force, power and work. In very rapid movements, elastic mechanisms can amplify muscle power by storing the work of muscle contraction slowly and releasing it rapidly. When energy must be dissipated rapidly, such as in landing from a jump, energy stored rapidly in elastic elements can be released more slowly to stretch muscle contractile elements, reducing the power input to muscle and possibly protecting it from damage. Elastic mechanisms identified so far rely primarily on in-series tendons, but many structures within muscles exhibit spring-like properties. Actomyosin cross-bridges, actin and myosin filaments, titin, and the connective tissue scaffolding of the extracellular matrix all have the potential to store and recover elastic energy during muscle contraction. The potential contribution of these elements can be assessed from their stiffness and estimates of the strain they undergo during muscle function. Such calculations provide boundaries for the possible roles these springs might play in locomotion, and may help to direct future studies of the uses of elastic elements in muscle. © 2016. Published by The Company of Biologists Ltd.

  11. Comparison of muscle/lean mass measurement methods: correlation with functional and biochemical testing.

    Science.gov (United States)

    Buehring, B; Siglinsky, E; Krueger, D; Evans, W; Hellerstein, M; Yamada, Y; Binkley, N

    2018-03-01

    DXA-measured lean mass is often used to assess muscle mass but has limitations. Thus, we compared DXA lean mass with two novel methods-bioelectric impedance spectroscopy and creatine (methyl-d3) dilution. The examined methodologies did not measure lean mass similarly and the correlation with muscle biomarkers/function varied. Muscle function tests predict adverse health outcomes better than lean mass measurement. This may reflect limitations of current mass measurement methods. Newer approaches, e.g., bioelectric impedance spectroscopy (BIS) and creatine (methyl-d3) dilution (D3-C), may more accurately assess muscle mass. We hypothesized that BIS and D3-C measured muscle mass would better correlate with function and bone/muscle biomarkers than DXA measured lean mass. Evaluations of muscle/lean mass, function, and serum biomarkers were obtained in older community-dwelling adults. Mass was assessed by DXA, BIS, and orally administered D3-C. Grip strength, timed up and go, and jump power were examined. Potential muscle/bone serum biomarkers were measured. Mass measurements were compared with functional and serum data using regression analyses; differences between techniques were determined by paired t tests. Mean (SD) age of the 112 (89F/23M) participants was 80.6 (6.0) years. The lean/muscle mass assessments were correlated (.57-.88) but differed (p Lean mass measures were unrelated to the serum biomarkers measured. These three methodologies do not similarly measure muscle/lean mass and should not be viewed as being equivalent. Functional tests assessing maximal muscle strength/power (grip strength and jump power) correlated with all mass measures whereas gait speed was not. None of the selected serum measures correlated with mass. Efforts to optimize muscle mass assessment and identify their relationships with health outcomes are needed.

  12. Skeletal muscle function and hypertrophy are diminished in old age.

    NARCIS (Netherlands)

    Degens, H.; Alway, S.E.

    2003-01-01

    Muscle loss occurs during aging. To investigate whether the hypertrophic response is attenuated at old age, we used male Fischer 344 (26 months old; n = 5) and Fischer 344 x Brown Norway rats (6, 9, and 33 months old; n = 8, 10, and 6, respectively). Hypertrophy of the left plantaris muscle was

  13. Histochemical and functional fibre typing of the rabbit masseter muscle

    NARCIS (Netherlands)

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

    1990-01-01

    The fibre-type distribution of the masseter muscle of the rabbit was studied by means of the myosin-ATPase and succinate dehydrogenase reactions. Six different fibre types were found and these were unequally distributed between and within the anatomical compartments of the muscle. Most of the

  14. Serotonin modulates muscle function in the medicinal leech Hirudo verbana.

    Science.gov (United States)

    Gerry, Shannon P; Ellerby, David J

    2011-12-23

    The body wall muscles of sanguivorous leeches power mechanically diverse behaviours: suction feeding, crawling and swimming. These require longitudinal muscle to exert force over an extremely large length range, from 145 to 46 per cent of the mean segmental swimming length. Previous data, however, suggest that leech body wall muscle has limited capacity for force production when elongated. Serotonin (5-HT) alters the passive properties of the body wall and stimulates feeding. We hypothesized that 5-HT may also have a role in allowing force production in elongated muscle by changing the shape of the length-tension relationship (LTR). LTRs were measured from longitudinal muscle strips in vitro in physiological saline with and without the presence of 10 µM 5-HT. The LTR was much broader than previously measured for leech muscle. Rather than shifting the LTR, 5-HT reduced passive muscle tonus and increased active stress at all lengths. In addition to modulating leech behaviour and passive mechanical properties, 5-HT probably enhances muscle force and work production during locomotion and feeding.

  15. Whole-muscle reimplantation with microneurovascular anastomoses. A functional and histological study.

    Science.gov (United States)

    Prendergast, F. J.; McGeachie, J. K.; Edis, R. H.; Allbrook, D.

    1977-01-01

    Whole tibialis anterior muscles were removed from a number of dogs and were then reimplanted in the original sites. Microsurgical anastomoses of the major nerve, artery, and vein were performed. Biopsy revealed some minor regenerative changes in the muscle a few weeks after the operation. Electromyographic recordings 6-9 months after implantation showed near-complete functional recovery of the muscles. This was confirmed histologically. The study demonstrates not only that whole-muscle reimplantation is technically feasible but that a functionally satisfactory result may be expected. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 PMID:900796

  16. Structural, biochemical, cellular, and functional changes in skeletal muscle extracellular matrix with aging

    DEFF Research Database (Denmark)

    Kragstrup, T W; Kjaer, M; Mackey, A L

    2011-01-01

    in skeletal muscle ECM contribute to the increased stiffness and impairment in force generated by the contracting muscle fibers seen with aging. The cellular interactions provide and potentially coordinate an adaptation to mechanical loading and ensure successful regeneration after muscle injury. Some......The extracellular matrix (ECM) of skeletal muscle is critical for force transmission and for the passive elastic response of skeletal muscle. Structural, biochemical, cellular, and functional changes in skeletal muscle ECM contribute to the deterioration in muscle mechanical properties with aging......-links and a buildup of advanced glycation end-product cross-links. Altered mechanotransduction, poorer activation of satellite cells, poorer chemotactic and delayed inflammatory responses, and a change in modulators of the ECM are important cellular changes. It is possible that the structural and biochemical changes...

  17. Structural, biochemical, cellular, and functional changes in skeletal muscle extracellular matrix with aging

    DEFF Research Database (Denmark)

    Kragstrup, T W; Kjaer, M; Mackey, A L

    2011-01-01

    The extracellular matrix (ECM) of skeletal muscle is critical for force transmission and for the passive elastic response of skeletal muscle. Structural, biochemical, cellular, and functional changes in skeletal muscle ECM contribute to the deterioration in muscle mechanical properties with aging......-links and a buildup of advanced glycation end-product cross-links. Altered mechanotransduction, poorer activation of satellite cells, poorer chemotactic and delayed inflammatory responses, and a change in modulators of the ECM are important cellular changes. It is possible that the structural and biochemical changes...... in skeletal muscle ECM contribute to the increased stiffness and impairment in force generated by the contracting muscle fibers seen with aging. The cellular interactions provide and potentially coordinate an adaptation to mechanical loading and ensure successful regeneration after muscle injury. Some...

  18. Structural, biochemical, cellular, and functional changes in skeletal muscle extracellular matrix with aging

    DEFF Research Database (Denmark)

    Kragstrup, Tue Wenzel; Kjaer, M; Mackey, A L

    2011-01-01

    -links and a buildup of advanced glycation end-product cross-links. Altered mechanotransduction, poorer activation of satellite cells, poorer chemotactic and delayed inflammatory responses, and a change in modulators of the ECM are important cellular changes. It is possible that the structural and biochemical changes......The extracellular matrix (ECM) of skeletal muscle is critical for force transmission and for the passive elastic response of skeletal muscle. Structural, biochemical, cellular, and functional changes in skeletal muscle ECM contribute to the deterioration in muscle mechanical properties with aging...... in skeletal muscle ECM contribute to the increased stiffness and impairment in force generated by the contracting muscle fibers seen with aging. The cellular interactions provide and potentially coordinate an adaptation to mechanical loading and ensure successful regeneration after muscle injury. Some...

  19. Impaired Arterial Smooth Muscle Cell Vasodilatory Function In Methamphetamine Users

    Directory of Open Access Journals (Sweden)

    Ghaemeh Nabaei

    2017-02-01

    Full Text Available Objectives: Methamphetamine use is a strong risk factor for stroke. This study was designed to evaluate arterial function and structure in methamphetamine users ultrasonographically. Methods: In a cross-sectional study, 20 methamphetamine users and 21 controls, aged between 20 and 40years, were enrolled. Common carotid artery intima-media thickness (CCA-IMT marker of early atherogenesis, flow-mediated dilatation (FMD determinants of endothelium-dependent vasodilation, and nitroglycerine-mediated dilatation (NMD independent marker of vasodilation were measured in two groups. Results: There were no significant differences between the two groups regarding demographic and metabolic characteristics. The mean (±SD CCA-IMT in methamphetamine users was 0.58±0.09mm, versus 0.59±0.07mm in the controls (p=0.84. Likewise, FMD% was not significantly different between the two groups [7.6±6.1% in methamphetamine users vs. 8.2±5.1% in the controls; p=0.72], nor were peak flow and shear rate after hyperemia. However, NMD% was considerably decreased in the methamphetamine users [8.5±7.8% in methamphetamine users vs. 13.4±6.2% in controls; p=0.03]. Conclusion: According to our results, NMD is reduced among otherwise healthy methamphetamine users, which represents smooth muscle dysfunction in this group. This may contribute to the high risk of stroke among methamphetamine users.

  20. Respiratory muscle function and exercise limitation in patients with chronic obstructive pulmonary disease: a review.

    Science.gov (United States)

    Charususin, Noppawan; Dacha, Sauwaluk; Gosselink, Rik; Decramer, Marc; Von Leupoldt, Andreas; Reijnders, Thomas; Louvaris, Zafeiris; Langer, Daniel

    2018-01-01

    Respiratory muscle dysfunction is common and contributes to dyspnea and exercise limitation in patients with chronic obstructive pulmonary disease (COPD). Improving dynamic function of respiratory muscles during exercise might help to reduce symptoms and improve exercise capacity. Areas covered: The aims of this review are to 1) summarize physiological mechanisms linking respiratory muscle dysfunction to dyspnea and exercise limitation; 2) provide an overview of available therapeutic approaches to better maintain load-capacity balance of respiratory muscles during exercise; and 3) to summarize current knowledge on potential mechanisms explaining effects of interventions aimed at optimizing dynamic respiratory muscle function with a special focus on inspiratory muscle training. Expert commentary: Several mechanisms which are potentially linking improvements in dynamic respiratory muscle function to symptomatic and functional benefits have not been studied so far in COPD patients. Examples of underexplored areas include the study of neural processes related to the relief of acute dyspnea and the competition between respiratory and peripheral muscles for limited energy supplies during exercise. Novel methodologies are available to non-invasively study these mechanisms. Better insights into the consequences of dynamic respiratory muscle dysfunction will hopefully contribute to further refine and individualize therapeutic approaches in patients with COPD.

  1. Muscles in "concert": study of primary motor cortex upper limb functional topography.

    Directory of Open Access Journals (Sweden)

    Jean-Marc Melgari

    Full Text Available BACKGROUND: Previous studies with Transcranial Magnetic Stimulation (TMS have focused on the cortical representation of limited group of muscles. No attempts have been carried out so far to get simultaneous recordings from hand, forearm and arm with TMS in order to disentangle a 'functional' map providing information on the rules orchestrating muscle coupling and overlap. The aim of the present study is to disentangle functional associations between 12 upper limb muscles using two measures: cortical overlapping and cortical covariation of each pair of muscles. Interhemispheric differences and the influence of posture were evaluated as well. METHODOLOGY/PRINCIPAL FINDINGS: TMS mapping studies of 12 muscles belonging to hand, forearm and arm were performed. Findings demonstrate significant differences between the 66 pairs of muscles in terms of cortical overlapping: extremely high for hand-forearm muscles and very low for arm vs hand/forearm muscles. When right and left hemispheres were compared, overlapping between all possible pairs of muscles in the left hemisphere (62.5% was significantly higher than in the right one (53.5% . The arm/hand posture influenced both measures of cortical association, the effect of Position being significant [p = .021] on overlapping, resulting in 59.5% with prone vs 53.2% with supine hand, but only for pairs of muscles belonging to hand and forearm, while no changes occurred in the overlapping of proximal muscles with those of more distal districts. CONCLUSIONS/SIGNIFICANCE: Larger overlapping in the left hemisphere could be related to its lifetime higher training of all twelve muscles studied with respect to the right hemisphere, resulting in larger intra-cortical connectivity within primary motor cortex. Altogether, findings with prone hand might be ascribed to mechanisms facilitating coupling of muscles for object grasping and lifting -with more proximal involvement for joint stabilization- compared to supine

  2. Abdicating power for control: a precision timing strategy to modulate function of flight power muscles

    Science.gov (United States)

    Sponberg, S.; Daniel, T. L.

    2012-01-01

    Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power–phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left–right pairs of flight muscles normally fire precisely, within 0.5–0.6 ms of each other; (ii) during a yawing optomotor response, left—right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left–right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left—right timing differences. Because many organisms also have muscles operating with high power–phase gains (Δpower/Δphase), this motor control strategy may be ubiquitous in locomotor systems. PMID:22833272

  3. The effect of the inspiratory muscle training on functional ability in stroke patients

    OpenAIRE

    Jung, Nam-Jin; Na, Sang-Su; Kim, Seung-Kyu; Hwangbo, Gak

    2017-01-01

    [Purpose] This study was to find out an inspiratory muscle training (IMT) program therapeutic effects on stroke patients’ functional ability. [Subjects and Methods] Twenty stroke patients were assigned to one of two groups: inspiratory muscle training (n=10), and control (n=10), randomization. The inspiratory muscle training participants undertook an exercise program for 30 minute per times, 5 times a week for 6 weeks. The investigator measured the patients’ trunk impairment scale (TIS) and 6...

  4. Sodium channelopathies of skeletal muscle result from gain or loss of function

    OpenAIRE

    Jurkat-Rott, Karin; Holzherr, Boris; Fauler, Michael; Lehmann-Horn, Frank

    2010-01-01

    Five hereditary sodium channelopathies of skeletal muscle have been identified. Prominent symptoms are either myotonia or weakness caused by an increase or decrease of muscle fiber excitability. The voltage-gated sodium channel NaV1.4, initiator of the muscle action potential, is mutated in all five disorders. Pathogenetically, both loss and gain of function mutations have been described, the latter being the more frequent mechanism and involving not just the ion-conducting pore, but aberrant...

  5. Assessment of muscle function using hybrid PET/MRI

    DEFF Research Database (Denmark)

    Haddock, Bryan; Holm, Søren; Poulsen, Jákup M.

    2017-01-01

    in muscle T2 may be used as a surrogate marker for glucose uptake and lead to an improved insight into the metabolic changes that occur with muscle activation. Such knowledge may lead to improved treatment strategies in patients with neuromuscular pathologies such as stroke, spinal cord injuries......Purpose: The aim of this study was to determine the relationship between relative glucose uptake and MRI T2 changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans. Methods: Ten young healthy recreationally active men (age 21 – 28 years) were injected with 18F......-FDG while activating the quadriceps of one leg with repeated knee extension exercises followed by hand-grip exercises for one arm. Immediately following the exercises, the subjects were scanned simultaneously with 18F-FDG PET/MRI and muscle groups were evaluated for increases in 18F-FDG uptake and MRI T2...

  6. Effects of aging on mitochondrial function in skeletal muscle of American Quarter Horses

    Science.gov (United States)

    Li, Chengcheng; White, Sarah H.; Warren, Lori K.

    2016-01-01

    Skeletal muscle function, aerobic capacity, and mitochondrial (Mt) function have been found to decline with age in humans and rodents. However, not much is known about age-related changes in Mt function in equine skeletal muscle. Here, we compared fiber-type composition and Mt function in gluteus medius and triceps brachii muscle between young (age 1.8 ± 0.1 yr, n = 24) and aged (age 17-25 yr, n = 10) American Quarter Horses. The percentage of myosin heavy chain (MHC) IIX was lower in aged compared with young muscles (gluteus, P = 0.092; triceps, P = 0.012), while the percentages of MHC I (gluteus; P gluteus, but decreased in aged triceps (P = 0.023). Cytochrome-c oxidase (COX) activity per milligram tissue and per Mt unit decreased with age in gluteus (P gluteus and triceps (P = 0.023 and P < 0.001, respectively). Mt respiration of permeabilized muscle fibers per milligram tissue was unaffected by age in both muscles. Main effects of age appeared when respiration was normalized to Mt content, with increases in LEAK, oxidative phosphorylation capacity, and electron transport system capacity (P = 0.038, P = 0.045, and P = 0.007, respectively), independent of muscle. In conclusion, equine skeletal muscle aging was accompanied by a shift in fiber-type composition, decrease in Mt density and COX activity, but preserved Mt respiratory function. PMID:27283918

  7. Role of skeletal muscle in lung development.

    Science.gov (United States)

    Baguma-Nibasheka, Mark; Gugic, Dijana; Saraga-Babic, Mirna; Kablar, Boris

    2012-07-01

    Skeletal (striated) muscle is one of the four basic tissue types, together with the epithelium, connective and nervous tissues. Lungs, on the other hand, develop from the foregut and among various cell types contain smooth, but not skeletal muscle. Therefore, during earlier stages of development, it is unlikely that skeletal muscle and lung depend on each other. However, during the later stages of development, respiratory muscle, primarily the diaphragm and the intercostal muscles, execute so called fetal breathing-like movements (FBMs), that are essential for lung growth and cell differentiation. In fact, the absence of FBMs results in pulmonary hypoplasia, the most common cause of death in the first week of human neonatal life. Most knowledge on this topic arises from in vivo experiments on larger animals and from various in vitro experiments. In the current era of mouse mutagenesis and functional genomics, it was our goal to develop a mouse model for pulmonary hypoplasia. We employed various genetically engineered mice lacking different groups of respiratory muscles or lacking all the skeletal muscle and established the criteria for pulmonary hypoplasia in mice, and therefore established a mouse model for this disease. We followed up this discovery with systematic subtractive microarray analysis approach and revealed novel functions in lung development and disease for several molecules. We believe that our approach combines elements of both in vivo and in vitro approaches and allows us to study the function of a series of molecules in the context of lung development and disease and, simultaneously, in the context of lung's dependence on skeletal muscle-executed FBMs.

  8. [Correlations Between Joint Proprioception, Muscle Strength, and Functional Ability in Patients with Knee Osteoarthritis].

    Science.gov (United States)

    Chen, Yoa; Yu, Yong; He, Cheng-qi

    2015-11-01

    To establish correlations between joint proprioception, muscle flexion and extension peak torque, and functional ability in patients with knee osteoarthritis (OA). Fifty-six patients with symptomatic knee OA were recruited in this study. Both proprioceptive acuity and muscle strength were measured using the isomed-2000 isokinetic dynamometer. Proprioceptive acuity was evaluated by establishing the joint motion detection threshold (JMDT). Muscle strength was evaluated by Max torque (Nm) and Max torque/weight (Nm/ kg). Functional ability was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index physical function (WOMAC-PF) questionnaire. Correlational analyses were performed between proprioception, muscle strength, and functional ability. A multiple stepwise regression model was established, with WOMAC-PF as dependent variable and patient age, body mass index (BMI), visual analogue scale (VAS)-score, mean grade for Kellgren-Lawrance of both knees, mean strength for quadriceps and hamstring muscles of both knees, and mean JMDT of both knees as independent variables. Poor proprioception (high JMDT) was negatively correlated with muscle strength (Pproprioception (high JMDT) and joint pain (WOMAC pain score), and between knee proprioception (high JMDT) and joint stiffness (WOMAC stiffness score). Poor proprioception (high JMDT) was correlated with limitation in functional ability (WOMAC physical function score r=0.659, Pproprioception is associated with poor muscle strength and limitation in functional ability. Patients with symptomatic OA of knees commonly endure with moderate to considerable dysfunction, which is associated with poor proprioception (high JMDT) and high VAS-scale score.

  9. Muscle activity during functional coordination training: implications for strength gain and rehabilitation

    DEFF Research Database (Denmark)

    Jørgensen, Marie Birk; Andersen, Lars Louis; Kirk, Niels

    2010-01-01

    The purpose of this study was to evaluate if different types, body positions, and levels of progression of functional coordination exercises can provide sufficiently high levels of muscle activity to improve strength of the neck, shoulder, and trunk muscles. Nine untrained women were familiarized...... for the attained muscle activity. Body position during the exercises was important for the activity of the erector spinae, and level of progression was important for the activity of the trapezius. The findings indicate that depending on type, body position, and level of progression, functional coordination...... training can be performed with a muscle activity sufficient for strength gain. Functional coordination training may therefore be a good choice for prevention or rehabilitation of musculoskeletal pain or injury in the neck, shoulder, or trunk muscles....

  10. Ventilatory muscle strength, diaphragm thickness and pulmonary function in world-class powerlifters.

    Science.gov (United States)

    Brown, Peter I; Venables, Heather K; Liu, Hymsuen; de-Witt, Julie T; Brown, Michelle R; Faghy, Mark A

    2013-11-01

    Resistance training activates the ventilatory muscles providing a stimulus similar to ventilatory muscle training. We examined the effects of elite powerlifting training upon ventilatory muscle strength, pulmonary function and diaphragm thickness in world-class powerlifters (POWER) and a control group (CON) with no history of endurance or resistance training, matched for age, height and body mass. Body composition was assessed using single-frequency bioelectrical impedance. Maximal static volitional inspiratory (P(I,max)) and expiratory (P(E,max)) mouth pressures, diaphragm thickness (T(di)) derived from ultrasound measurements and pulmonary function from maximal flow volume loops were measured. There were no differences in physical characteristics or pulmonary function between groups. P(I,max) (22 %, P powerlifters improve ventilatory muscle strength and increases diaphragm size. Whole-body resistance training may be an appropriate training mode to attenuate the effects of ventilatory muscle weakness experienced with ageing and some disease states.

  11. Effects of isokinetic calf muscle exercise program on muscle strength and venous function in patients with chronic venous insufficiency.

    Science.gov (United States)

    Ercan, Sabriye; Çetin, Cem; Yavuz, Turhan; Demir, Hilmi M; Atalay, Yurdagül B

    2017-01-01

    Objective The aim of this study was to observe the change of the ankle joint range of motion, the muscle strength values measured with an isokinetic dynamometer, pain scores, quality of life scale, and venous return time in chronic venous insufficiency diagnosed patients by prospective follow-up after 12-week exercise program including isokinetic exercises. Methods The patient group of this study comprised 27 patients (23 female, 4 male) who were diagnosed with chronic venous insufficiency. An exercise program including isokinetic exercise for the calf muscle was given to patients three days per week for 12 weeks. At the end of 12 weeks, five of the patients left the study due to inadequate compliance with the exercise program. As a result, control data of 22 patients were included. Ankle joint range of active motion, isokinetic muscle strength, pain, quality of life, and photoplethysmography measurements were assessed before starting and after the exercise program. Results Evaluating changes of the starting and control data depending on time showed that all isokinetic muscle strength measurement parameters, range of motion, and overall quality of life values of patients improved. Venous return time values have also increased significantly ( p strength has been provided with exercise therapy in patients with chronic venous insufficiency. It has been determined that the increase in muscle strength affected the venous pump and this ensured improvement in venous function and range of motion of the ankle. In addition, it has been detected that pain reduced and quality of life improved after the exercise program.

  12. Altered cross-bridge properties in skeletal muscle dystrophies

    Directory of Open Access Journals (Sweden)

    Aziz eGuellich

    2014-10-01

    Full Text Available Force and motion generated by skeletal muscle ultimately depends on the cyclical interaction of actin with myosin. This mechanical process is regulated by intracellular Ca2+ through the thin filament-associated regulatory proteins i.e.; troponins and tropomyosin. Muscular dystrophies are a group of heterogeneous genetic affections characterized by progressive degeneration and weakness of the skeletal muscle as a consequence of loss of muscle tissue which directly reduces the number of potential myosin cross-bridges involved in force production. Mutations in genes responsible for skeletal muscle dystrophies have been shown to modify the function of contractile proteins and cross-bridge interactions. Altered gene expression or RNA splicing or post-translational modifications of contractile proteins such as those related to oxidative stress, may affect cross-bridge function by modifying key proteins of the excitation-contraction coupling. Micro-architectural change in myofilament is another mechanism of altered cross-bridge performance. In this review, we provide an overview about changes in cross-bridge performance in skeletal muscle dystrophies and discuss their ultimate impacts on striated muscle function.

  13. Inspiratory Muscle Training and Functional Capacity in Patients Undergoing Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    André Luiz Lisboa Cordeiro

    Full Text Available Abstract Introduction: Cardiac surgery is a highly complex procedure which generates worsening of lung function and decreased inspiratory muscle strength. The inspiratory muscle training becomes effective for muscle strengthening and can improve functional capacity. Objective: To investigate the effect of inspiratory muscle training on functional capacity submaximal and inspiratory muscle strength in patients undergoing cardiac surgery. Methods: This is a clinical randomized controlled trial with patients undergoing cardiac surgery at Instituto Nobre de Cardiologia. Patients were divided into two groups: control group and training. Preoperatively, were assessed the maximum inspiratory pressure and the distance covered in a 6-minute walk test. From the third postoperative day, the control group was managed according to the routine of the unit while the training group underwent daily protocol of respiratory muscle training until the day of discharge. Results: 50 patients, 27 (54% males were included, with a mean age of 56.7±13.9 years. After the analysis, the training group had significant increase in maximum inspiratory pressure (69.5±14.9 vs. 83.1±19.1 cmH2O, P=0.0073 and 6-minute walk test (422.4±102.8 vs. 502.4±112.8 m, P=0.0031. Conclusion: We conclude that inspiratory muscle training was effective in improving functional capacity submaximal and inspiratory muscle strength in this sample of patients undergoing cardiac surgery.

  14. Inspiratory Muscle Training and Functional Capacity in Patients Undergoing Cardiac Surgery.

    Science.gov (United States)

    Cordeiro, André Luiz Lisboa; de Melo, Thiago Araújo; Neves, Daniela; Luna, Julianne; Esquivel, Mateus Souza; Guimarães, André Raimundo França; Borges, Daniel Lago; Petto, Jefferson

    2016-04-01

    Cardiac surgery is a highly complex procedure which generates worsening of lung function and decreased inspiratory muscle strength. The inspiratory muscle training becomes effective for muscle strengthening and can improve functional capacity. To investigate the effect of inspiratory muscle training on functional capacity submaximal and inspiratory muscle strength in patients undergoing cardiac surgery. This is a clinical randomized controlled trial with patients undergoing cardiac surgery at Instituto Nobre de Cardiologia. Patients were divided into two groups: control group and training. Preoperatively, were assessed the maximum inspiratory pressure and the distance covered in a 6-minute walk test. From the third postoperative day, the control group was managed according to the routine of the unit while the training group underwent daily protocol of respiratory muscle training until the day of discharge. 50 patients, 27 (54%) males were included, with a mean age of 56.7±13.9 years. After the analysis, the training group had significant increase in maximum inspiratory pressure (69.5±14.9 vs. 83.1±19.1 cmH2O, P=0.0073) and 6-minute walk test (422.4±102.8 vs. 502.4±112.8 m, P=0.0031). We conclude that inspiratory muscle training was effective in improving functional capacity submaximal and inspiratory muscle strength in this sample of patients undergoing cardiac surgery.

  15. AMPKγ3 is dispensable for skeletal muscle hypertrophy induced by functional overload.

    Science.gov (United States)

    Riedl, Isabelle; Osler, Megan E; Björnholm, Marie; Egan, Brendan; Nader, Gustavo A; Chibalin, Alexander V; Zierath, Juleen R

    2016-03-15

    Mechanisms regulating skeletal muscle growth involve a balance between the activity of serine/threonine protein kinases, including the mammalian target of rapamycin (mTOR) and 5'-AMP-activated protein kinase (AMPK). The contribution of different AMPK subunits to the regulation of cell growth size remains inadequately characterized. Using AMPKγ3 mutant-overexpressing transgenic Tg-Prkag3(225Q) and AMPKγ3-knockout (Prkag3(-/-)) mice, we investigated the requirement for the AMPKγ3 isoform in functional overload-induced muscle hypertrophy. Although the genetic disruption of the γ3 isoform did not impair muscle growth, control sham-operated AMPKγ3-transgenic mice displayed heavier plantaris muscles in response to overload hypertrophy and underwent smaller mass gain and lower Igf1 expression compared with wild-type littermates. The mTOR signaling pathway was upregulated with functional overload but unchanged between genetically modified animals and wild-type littermates. Differences in AMPK-related signaling pathways between transgenic, knockout, and wild-type mice did not impact muscle hypertrophy. Glycogen content was increased following overload in wild-type mice. In conclusion, our functional, transcriptional, and signaling data provide evidence against the involvement of the AMPKγ3 isoform in the regulation of skeletal muscle hypertrophy. Thus, the AMPKγ3 isoform is dispensable for functional overload-induced muscle growth. Mechanical loading can override signaling pathways that act as negative effectors of mTOR signaling and consequently promote skeletal muscle hypertrophy. Copyright © 2016 the American Physiological Society.

  16. Exercise induced effects on muscle function and range of motion in patients with hip osteoarthritis

    DEFF Research Database (Denmark)

    Bieler, Theresa; Siersma, Volkert; Magnusson, S Peter

    2018-01-01

    BACKGROUND AND PURPOSE: Patients with hip osteoarthritis have impairments in muscle function (muscle strength and power) and hip range of motion (ROM), and it is commonly believed that effective clinical management of osteoarthritis should address these impairments to reduce pain and disability. ...

  17. An education program about pelvic floor muscles improved women’s knowledge but not pelvic floor muscle function, urinary incontinence or sexual function: a randomised trial

    Directory of Open Access Journals (Sweden)

    Roberta Leopoldino de Andrade

    2018-04-01

    Full Text Available Question: Does an educational program with instructions for performing ‘the Knack’ improve voluntary contraction of the pelvic floor muscles, reduce reports of urinary incontinence, improve sexual function, and promote women’s knowledge of the pelvic floor muscles? Design: Randomised, controlled trial with concealed allocation, intention-to-treat analysis and blinded assessors. Participants: Ninety-nine women from the local community. Intervention: The experimental group (n = 50 received one lecture per week for 4 weeks, and instructions for performing ‘the Knack’. The control group (n = 49 received no intervention. Outcome measures: The primary outcome was maximum voluntary contraction of the pelvic floor muscles measured using manometry. Secondary outcomes were: ability to contract the pelvic floor muscles measured using vaginal palpation; severity of urinary incontinence measured by the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF scored from 0 to 21; self-reported sexual function; and knowledge related to the pelvic floor. Outcomes were measured at baseline and after 4 weeks. Results: The intervention did not significantly improve: maximum voluntary contraction (MD 2.7 cmH2O higher in the experimental group, 95% CI –0.5 to 5.9; ability to contract the pelvic floor muscles (RR 2.18, 95% CI 0.49 to 9.65; or self-reported severity of urinary incontinence (MD 1 point greater reduction in the experimental group, 95% CI –3 to 1. Sexual function did not significantly differ between groups, but very few of the women engaged in sexual activity during the study period. The educational program did, however, significantly increase women’s knowledge related to the location, functions and dysfunctions of the pelvic floor muscles, and treatment options. Conclusion: Education and teaching women to perform ‘the Knack’ had no significant effect on voluntary contraction of the pelvic floor muscles

  18. An education program about pelvic floor muscles improved women's knowledge but not pelvic floor muscle function, urinary incontinence or sexual function: a randomised trial.

    Science.gov (United States)

    de Andrade, Roberta Leopoldino; Bø, Kari; Antonio, Flavia Ignácio; Driusso, Patricia; Mateus-Vasconcelos, Elaine Cristine Lemes; Ramos, Salvador; Julio, Monica Pitanguy; Ferreira, Cristine Homsi Jorge

    2018-04-01

    Does an educational program with instructions for performing 'the Knack' improve voluntary contraction of the pelvic floor muscles, reduce reports of urinary incontinence, improve sexual function, and promote women's knowledge of the pelvic floor muscles? Randomised, controlled trial with concealed allocation, intention-to-treat analysis and blinded assessors. Ninety-nine women from the local community. The experimental group (n=50) received one lecture per week for 4 weeks, and instructions for performing 'the Knack'. The control group (n=49) received no intervention. The primary outcome was maximum voluntary contraction of the pelvic floor muscles measured using manometry. Secondary outcomes were: ability to contract the pelvic floor muscles measured using vaginal palpation; severity of urinary incontinence measured by the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) scored from 0 to 21; self-reported sexual function; and knowledge related to the pelvic floor. Outcomes were measured at baseline and after 4 weeks. The intervention did not significantly improve: maximum voluntary contraction (MD 2.7 cmH 2 O higher in the experimental group, 95% CI -0.5 to 5.9); ability to contract the pelvic floor muscles (RR 2.18, 95% CI 0.49 to 9.65); or self-reported severity of urinary incontinence (MD 1 point greater reduction in the experimental group, 95% CI -3 to 1). Sexual function did not significantly differ between groups, but very few of the women engaged in sexual activity during the study period. The educational program did, however, significantly increase women's knowledge related to the location, functions and dysfunctions of the pelvic floor muscles, and treatment options. Education and teaching women to perform 'the Knack' had no significant effect on voluntary contraction of the pelvic floor muscles, urinary incontinence or sexual function, but it promoted women's knowledge about the pelvic floor. Brazilian Registry of Clinical

  19. Histotopographical study of human periocular elastic fibers using aldehyde-fuchsin staining with special reference to the sleeve and pulley system for extraocular rectus muscles.

    Science.gov (United States)

    Osanai, Hajime; Murakami, Gen; Ohtsuka, Aiji; Suzuki, Daisuke; Nakagawa, Takashi; Tatsumi, Haruyuki

    2009-09-01

    The aim of this study was to investigate the detailed configuration of periocular elastic fibers. Semiserial paraffin sections were made using 40 whole orbital contents from 27 elderly cadavers and stained by the aldehyde-fuchsin method. Periocular tissues were classified into three types according to directions of the elastic fibers, i.e., tissues containing anteroposteriorly running elastic fibers, those with mediolateral fibers, and those with meshwork of fibers. Anteroposterior elastic fiber-dominant tissue was seen in the upper eyelid and newly defined pulley plate for the medial and lateral recti (MR, LR). Mediolateral fibers were predominant in the central part of the inferior rectus pulley. In the pulley plates for the MR and LR, anteroposteriorly running fibers encased the striated muscle. Tenon's capsule and the epimysium of the recti were mediolateral fiber-dominant. However, at the entrance of the muscle terminal where Tenon's capsule reflects and continues to the epimysium, composite elastic fibers provided a meshwork-like skeleton. The elastic mesh was also seen around the lacrimal canaliculi. The pulley for the recti seemed to be composed of two parts--a connective tissue plate encasing the recti and specialized Tenon's capsule at an entrance or porta of the muscle. For both parts, elastic fibers were major functional components. The anteroposterior elastic fibers in the MR and LR pulley plates, especially, seemed to receive anteroposteriorly directed stress and tension from these striated muscles. The elastic interfaces seemed to prevent any concentration of stress that would interfere with periocular striated muscle functions, including hypothetical active pulleys.

  20. Plasticity and function of human skeletal muscle in relation to disuse and rehabilitation

    DEFF Research Database (Denmark)

    Suetta, Charlotte

    2017-01-01

    of unilateral lower limb immobilisation) was assessed in healthy young and old individuals. In summary, chronic muscle disuse in the elderly was associated with marked quantitative as well as qualitative neuromuscular impairments. More specifically, decreases were observed in muscle strength, quadriceps muscle...... and implementation of effective countermeasures against physical frailty in the increasing population of elderly. Importantly therefore, the present experiments demonstrate that resistance training is highly effective of increasing maximal muscle strength and neuromuscular function in elderly post-operative patients...... size and myofibre area, muscle architecture, contractile properties and neuromuscular activation. Furthermore, substantial side-to-side differences in specific strength (MVC/LCSA) and normalised rapid muscle force capacity (RFD/CSA) were observed, indicating that a significant part of the observed...

  1. Muscle function and hydrodynamics limit power and speed in swimming frogs.

    Science.gov (United States)

    Clemente, Christofer J; Richards, Christopher

    2013-01-01

    Studies of the muscle force-velocity relationship and its derived n-shaped power-velocity curve offer important insights into muscular limits of performance. Given the power is maximal at 1/3 V(max), geometric scaling of muscle force coupled with fluid drag force implies that this optimal muscle-shortening velocity for power cannot be maintained across the natural body-size range. Instead, muscle velocity may decrease with increasing body size, conferring a similar n-shaped power curve with body size. Here we examine swimming speed and muscle function in the aquatic frog Xenopus laevis. Swimming speed shows an n-shaped scaling relationship, peaking at 47.35 g. Further, in vitro muscle function of the ankle extensor plantaris longus also shows an optimal body mass for muscle power output (47.27 g), reflecting that of swimming speed. These findings suggest that in drag-based aquatic systems, muscle-environment interactions vary with body size, limiting both the muscle's potential to produce power and the swimming speed.

  2. The relationship between lower limb muscle strength and lower extremity function in HIV disease

    Directory of Open Access Journals (Sweden)

    Peter C. Mhariwa

    2017-02-01

    Full Text Available Background: Human immunodeficiency virus (HIV negatively impacts muscle strength and function. This study aimed to establish the relationship between lower limb muscle strength and lower extremity function in HIV disease.Method: A cross-sectional study was undertaken with a sample of 113 HIV-positive participants. Lower limb muscle strength and self-reported function were established using dynamometry and the Lower Extremity Functional Scale (LEFS, respectively. Muscle strength and functional status were established in a subset of 30 HIV-negative participants to determine normative values.Results: Muscle strength for participants with HIV ranged from an ankle dorsiflexion mean of 9.33 kg/m2 to 15.79 kg/m2 in hip extensors. In the HIV-negative group, ankle dorsiflexors recorded 11.17 kg/m2, whereas hip extensors were the strongest, generating 17.68 kg/m2. In the HIV-positive group, linear regression showed a positive relationship between lower limb muscle strength and lower extremity function (r = 0.71, p = 0.00. Fifty per cent of the changes in lower extremity function were attributable to lower limb muscle strength. A simple linear regression model showed that lower limb ankle plantar flexors contributed the most to lower extremity function in this cohort, contrary to the literature which states that hip and trunk muscles are the most active in lower limb functional activities.Conclusion: Lower extremity strength impacts perceived function in individuals stabilised on antiretroviral therapy for HIV disease. These findings demonstrate that ankle plantar flexors produce more force over hip flexors. Careful attention should be paid to the implications for strength training in this population.

  3. Functioning of peripheral Ia pathways in infants with typical development: responses in antagonist muscle pairs.

    Science.gov (United States)

    Teulier, Caroline; Ulrich, Beverly D; Martin, Bernard

    2011-02-01

    In muscle responses of proprioceptive origin, including the stretch/tendon reflex (T-reflex), the corresponding reciprocal excitation and irradiation to distant muscles have been described from newborn infants to older adults. However, the functioning of other responses mediated primarily by Ia-afferents has not been investigated in infants. Understanding the typical development of these multiple pathways is critical to determining potential problems in their development in populations affected by neurological disease, such as spina bifida or cerebral palsy. Hence, the goal of the present study was to quantify the excitability of Ia-mediated responses in lower limb muscles of infants with typical development. These responses were elicited by mechanical stimulation applied to the distal tendons of the gastrocnemius-soleus (GS), tibialis anterior (TA) and quadriceps (QAD) muscles of both legs in twelve 2- to 10-month-old infants and recorded simultaneously in antagonist muscle pairs by surface EMG. Tendon taps alone elicited responses in either, both or neither muscle. The homonymous response (T-reflex) was less frequent in the TA than the GS or QAD muscle. An 80 Hz vibration superimposed on tendon taps induced primarily an inhibition of monosynaptic responses; however, facilitation also occurred in either muscle of the recorded pair. These responses were not influenced significantly by age or gender. Vibration alone produced a tonic reflex response in the vibrated muscle (TVR) and/or the antagonist muscle (AVR). However, for the TA muscle the TVR was more frequently elicited in older than younger infants. High variability was common to all responses. Overall, the random distribution and inconsistency of muscle responses suggests that the gain of Ia-mediated feedback is unstable. We propose that during infancy the central nervous system needs to learn to set stable feedback gain, or destination of proprioceptive assistance, based on their use during functional

  4. Changes in the Muscle strength and functional performance of healthy women with aging

    Directory of Open Access Journals (Sweden)

    Roghayeh Mousavikhatir

    2012-08-01

    Full Text Available Abstract Background: Lower limbs antigravity muscles weakness and decreased functional ability have significant role in falling. The aim of this study was to find the effects of aging on muscle strength and functional ability, determining the range of decreasing strength and functional ability and relationship between them in healthy women. Methods: Across-section study was performed on 101 healthy women aged 21-80 years. The participants were divided into six age groups. The maximum isometric strength of four muscle groups was measured using a hand-held dynamometer bilaterally. The functional ability was measured with functional reach (FR, timed get up and go (TGUG, single leg stance (SLS, and stairs walking (SW tests. Results: Muscle strength changes were not significant between 21-40 years of age, but decreased significantly thereafter. Also, there was a significant relationship between muscle strength and functional ability in age groups. Conclusion: Both muscle strength and functional ability is reduced as a result of aging, but the decrease in functional ability can be detected earlier.

  5. Functional reconstruction of the deltoid muscle following complete resection of musculoskeletal sarcoma.

    Science.gov (United States)

    Muramatsu, Keiichi; Ihara, Koichiro; Tominaga, Yasuhiro; Hashimoto, Takahiro; Taguchi, Toshihiko

    2014-07-01

    Although the deltoid muscle has been assumed to be an essential shoulder muscle, the full extent of postoperative functions of the upper extremity following its complete resection due to sarcoma has not been thoroughly investigated. In this study, we review patients who underwent wide resection for sarcoma in the deltoid muscle, followed by functional reconstruction using pedicled latissimus dorsi (LD) muscle transfer. Four patients with sarcoma arising in the deltoid muscle were reviewed. Tumor resection with a wide surgical margin resulted in loss of the entire deltoid muscle together with the axillary nerve. For reconstruction, the ipsilateral pedicled LD muscle was transferred on its neurovascular pedicle for use as a functional substitute. One case had local recurrence and the transferred LD myocutaneous flap was resected. There were no serious complications after the operation, and all flaps survived perfectly. Wound healing at both the recipient and donor sites was uneventful. Active abduction of the shoulder joint was >160° in all patients. The muscle manual test of shoulder flexion was good to normal and abduction was fair to good. Musculoskeletal Tumor Society scores were excellent in all cases and the average score was 92% (range, 87-93%). Our results suggest that removal of the entire deltoid muscle resulted in a slight impairment of function. Pedicled LD musculocutaneous flaps are useful for covering the defect that results from resection of the deltoid muscle and they contribute additional function to the affected shoulder. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  6. A physiologically based, multi-scale model of skeletal muscle structure and function

    Directory of Open Access Journals (Sweden)

    Oliver eRöhrle

    2012-09-01

    Full Text Available Models of skeletal muscle can be classified as phenomenological or biophysical. Phenomenological models predict the muscle's response to a specified input based on experimental measurements. Prominent phenomenological models are the Hill-type muscle models, which have been incorporated into rigid-body modelling frameworks, and three-dimensional continuum-mechanical models. Biophysically based models attempt to predict the muscle's response as emerging from the underlying physiology of the system. In this contribution, the conventional biophysically based modelling methodology is extended to include several structural and functional characteristics of skeletal muscle. The result is a physiologically based, multi-scale skeletal muscle finite element model that is capable of representing detailed, geometrical descriptions of skeletal muscle fibres and their grouping. Together with a well-established model of motor unit recruitment, the electro-physiological behaviour of single muscle fibres within motor units is computed and linked to a continuum-mechanical constitutive law. The bridging between the cellular level and the organ level has been achieved via a multi-scale constitutive law and homogenisation. The effect of homogenisation has been investigated by varying the number of embedded skeletal muscle fibres and/or motor units and computing the resulting exerted muscle forces while applying the same excitatory input. All simulations were conducted using an anatomically realistic finite element model of the Tibialis Anterior muscle. Given the fact that the underlying electro-physiological cellular muscle model is capable of modelling metabolic fatigue effects such as potassium accumulation in the T-tubular space and inorganic phosphate build-up, the proposed framework provides a novel simulation-based way to investigate muscle behaviour ranging from motor unit recruitment to force generation and fatigue.

  7. Cardiac myosin binding protein-C plays no regulatory role in skeletal muscle structure and function.

    Directory of Open Access Journals (Sweden)

    Brian Lin

    Full Text Available Myosin binding protein-C (MyBP-C exists in three major isoforms: slow skeletal, fast skeletal, and cardiac. While cardiac MyBP-C (cMyBP-C expression is restricted to the heart in the adult, it is transiently expressed in neonatal stages of some skeletal muscles. However, it is unclear whether this expression is necessary for the proper development and function of skeletal muscle. Our aim was to determine whether the absence of cMyBP-C alters the structure, function, or MyBP-C isoform expression in adult skeletal muscle using a cMyBP-C null mouse model (cMyBP-C((t/t. Slow MyBP-C was expressed in both slow and fast skeletal muscles, whereas fast MyBP-C was mostly restricted to fast skeletal muscles. Expression of these isoforms was unaffected in skeletal muscle from cMyBP-C((t/t mice. Slow and fast skeletal muscles in cMyBP-C((t/t mice showed no histological or ultrastructural changes in comparison to the wild-type control. In addition, slow muscle twitch, tetanus tension, and susceptibility to injury were all similar to the wild-type controls. Interestingly, fMyBP-C expression was significantly increased in the cMyBP-C((t/t hearts undergoing severe dilated cardiomyopathy, though this does not seem to prevent dysfunction. Additionally, expression of both slow and fast isoforms was increased in myopathic skeletal muscles. Our data demonstrate that i MyBP-C isoforms are differentially regulated in both cardiac and skeletal muscles, ii cMyBP-C is dispensable for the development of skeletal muscle with no functional or structural consequences in the adult myocyte, and iii skeletal isoforms can transcomplement in the heart in the absence of cMyBP-C.

  8. Aging impairs the recovery in mechanical muscle function following 4 days of disuse

    DEFF Research Database (Denmark)

    Hvid, Lars Grøndahl; Suetta, C; Nielsen, Jacob

    2014-01-01

    As aged individuals are frequently exposed to short-term disuse caused by disease or musculoskeletal injury, it is important to understand how short-term disuse and subsequent retraining affect lower limb mechanical muscle function. The purpose of the present study was, therefore, to investigate...... the effect of 4 days of lower limb disuse followed by 7 days of active recovery on mechanical muscle function of the knee extensors in young (24.3±0.9 years, n=11) and old (67.2±1.0 years, n=11) recreationally active healthy males. Slow and moderate dynamic muscle strength were assessed using isokinetic...... dynamometry (60 and 180° s(-1), respectively) along with isometric muscle strength and rapid muscle force capacity examined as contractile rate of force development (RFD), Impulse, and relative RFD (rRFD) during the initial phase of contraction (100 ms time interval relative to onset of contraction). Prior...

  9. Impaired physical function, loss of muscle mass and assessment of biomechanical properties in critical ill patients

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum

    2012-01-01

    Intensive care unit (ICU) admission is associated with muscle weakness and ICU survivors report sustained limitation of physical capacity for years after discharge. Limited information is available on the underlying biomechanical properties responsible for this muscle function impairment. A plaus......Intensive care unit (ICU) admission is associated with muscle weakness and ICU survivors report sustained limitation of physical capacity for years after discharge. Limited information is available on the underlying biomechanical properties responsible for this muscle function impairment....... A plausible contributor to the accentuated catabolic drive in ICU patients is a synergistic response to inflammation and inactivity leading to loss of muscle mass. As these entities are predominantly present in the early phase of ICU stay, interventions employed during this time frame may exhibit the greatest...

  10. Estrogen replacement, muscle composition, and physical function: the Health ABC Study

    NARCIS (Netherlands)

    Taaffe, D.R.; Newman, A.B.; Haggerty, C.L.; Colbert, L.H.; de Rekeneire, N.; Visser, M.; Goodpaster, B.H.; Nevitt, M.C.; Tylavsky, F.A.; Harris, T.B.

    2005-01-01

    PURPOSE: Although the beneficial effects of estrogen use on cardiovascular and cognitive function in postmenopausal women have been recently discredited, controversy remains regarding its usefulness for maintaining skeletal muscle mass or strength. Therefore, the purpose of this study was to

  11. Estrogen replacement, muscle composition, and physical function : The Health ABC Study

    NARCIS (Netherlands)

    Taaffe, Dennis R; Newman, Anne B; Haggerty, Catherine L; Colbert, Lisa H; de Rekeneire, Nathalie; Visser, Marjolein; Goodpaster, Bret H; Nevitt, Michael C; Tylavsky, Frances A; Harris, Tamara B

    2005-01-01

    PURPOSE: Although the beneficial effects of estrogen use on cardiovascular and cognitive function in postmenopausal women have been recently discredited, controversy remains regarding its usefulness for maintaining skeletal muscle mass or strength. Therefore, the purpose of this study was to

  12. Mitochondrial function in human skeletal muscle following high-altitude exposure

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Boushel, Robert; Wright-Paradis, Cynthia

    2013-01-01

    Studies regarding mitochondrial modifications in human skeletal muscle following acclimatization to high altitude are conflicting, and these inconsistencies may be due to the prevalence of representing mitochondrial function through static and isolated measurements of specific mitochondrial...... characteristics. The aim of this study, therefore, was to investigate mitochondrial function in response to high-altitude acclimatization through measurements of respiratory control in the vastus lateralis muscle. Skeletal muscle biopsies were obtained from 10 lowland natives prior to and again after a total of 9......-11 days of exposure to 4559 m. High-resolution respirometry was performed on the muscle samples to compare respiratory chain function and respiratory capacities. Respirometric analysis revealed that mitochondrial function was largely unaffected, because high-altitude exposure did not affect the capacity...

  13. Effect of strength training on muscle function in elderly hospitalized patients

    DEFF Research Database (Denmark)

    Suetta, C; Magnusson, S P; Beyer, N

    2007-01-01

    Immobilization due to hospitalization and major surgery leads to an increased risk of morbidity, disability and a decline in muscle function especially in frail elderly individuals. In fact, many elderly patients fail to regain their level of function and self-care before admission to hospital...... to induce muscle hypertrophy and increase muscle strength and functional performance in frail elderly individuals. Furthermore, there is increasing evidence that strength training is an effective method to restore muscle function in post-operative patients and in patients with chronic diseases. Despite this......, strength training is rarely used in the rehabilitation of hospitalized elderly patients. The current knowledge on this topic will be the focus of this review....

  14. Leg Muscle Mass and Foot Symptoms, Structure, and Function: The Johnston County Osteoarthritis Project.

    Science.gov (United States)

    Golightly, Yvonne M; Dufour, Alyssa B; Hannan, Marian T; Hillstrom, Howard J; Katz, Patricia P; Jordan, Joanne M

    2016-03-01

    Loss of muscle mass occurs with aging and in lower limbs it may be accelerated by foot problems. In this cross-sectional analysis, we evaluated the relationship of leg muscle mass to foot symptoms (presence or absence of pain, aching, or stiffness), structure while standing (high arch or low arch), and function while walking (pronated or supinated) in a community-based study of Caucasian and African American men and women who were 50-95 years old. In the Johnston County Osteoarthritis Project, leg muscle mass was measured with whole body dual-energy x-ray absorptiometry, and plantar foot pressure data, using predetermined values, were used to classify foot structure and function. Sex-specific crude and adjusted (age, body mass index, and race) linear regression models examined associations of leg muscle mass index (Leg muscle mass [kg]/Height [m](2)) with foot symptoms, structure, and function. Complete data were available for 1,037 participants (mean age 68 years, mean body mass index 31 kg/m(2), 68% women, 29% African American). In women, pronated foot function was associated with lower leg muscle mass in crude (p = .02), but not adjusted (p = .22), models. A low arch was associated with a higher leg muscle mass in adjusted models for both men and women (p Leg muscle mass was associated with foot structure in our biracial sample, whereas relations between leg muscle mass and foot function were attenuated by age, body mass index, and race. Future longitudinal analyses are needed to explain the temporal relationship between these conditions and how they relate to other aspects of impairment and physical function. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Functional alteration of breast muscle fatty acid profile by ...

    African Journals Online (AJOL)

    ajl yemi

    2011-03-28

    Mar 28, 2011 ... Breast muscle fatty acid (FA) profile was studied in broiler chickens fed at different levels of n-6:n-3 polyunsaturated fatty acid (PUFA) ratios ... The fast growing demand of omega-3 enriched meat and meat products, lead producers to ..... Chia seed (Salvia hispanica L.) as an [omega]-3 fatty acid source for ...

  16. Muscle glycogen and cell function - Location, location, location

    DEFF Research Database (Denmark)

    Ørtenblad, N; Nielsen, Joachim

    2015-01-01

    The importance of glycogen, as a fuel during exercise, is a fundamental concept in exercise physiology. The use of electron microscopy has revealed that glycogen is not evenly distributed in skeletal muscle fibers, but rather localized in distinct pools. In this review, we present the available...

  17. Functional anatomy of the extraocular muscles during vergence.

    Science.gov (United States)

    Demer, Joseph L; Clark, Robert A; Crane, Benjamin T; Tian, Jun-Ru; Narasimhan, Anita; Karim, Shaheen

    2008-01-01

    Magnetic resonance imaging (MRI) now enables precise visualisation of the mechanical state of the living human orbit, enabling inferences about the effects of mechanical factors on ocular kinematics. We used 3-dimensional (3D) magnetic search coil recordings and MRI to investigate the mechanical state of the orbit during vergence in humans. Horizontal convergence of 23 degrees from a remote to a near target aligned on one eye was geometrically ideal, and was associated with lens thickening and extorsion of the rectus pulley array of the aligned eye with superior oblique muscle relaxation and inferior oblique muscle contraction. There was no rectus muscle co-contraction. Subjective fusion through a 1 degree vertical prism caused a clockwise (CW) torsion in both eyes, as well as variable vertical and horizontal vergences that seldom corresponded to prism amount or direction. MRI under these conditions did not show consistent torsion of the rectus pulley array, but a complex pattern of changes in rectus extraocular muscle (EOM) crossections, consistent with co-contraction. Binocular fusion during vergence is accomplished by complex, 3D eye rotations seldom achieving binocular retinal correspondence. Vergence eye movements are sometimes associated with changes in rectus EOM pulling directions, and may sometimes be associated with co-contraction. Thus, extraretinal information about eye position would appear necessary to interpret binocular correspondence, and to avoid diplopia.

  18. The effect of the inspiratory muscle training on functional ability in stroke patients.

    Science.gov (United States)

    Jung, Nam-Jin; Na, Sang-Su; Kim, Seung-Kyu; Hwangbo, Gak

    2017-11-01

    [Purpose] This study was to find out an inspiratory muscle training (IMT) program therapeutic effects on stroke patients' functional ability. [Subjects and Methods] Twenty stroke patients were assigned to one of two groups: inspiratory muscle training (n=10), and control (n=10), randomization. The inspiratory muscle training participants undertook an exercise program for 30 minute per times, 5 times a week for 6 weeks. The investigator measured the patients' trunk impairment scale (TIS) and 6 minute walking test (6MW) for functional ability before and after IMT. [Results] The TIS appeared some significant differences in both groups before and after the training. The 6MW test showed some significant differences in the inspiratory muscle training group, but didn't show any significant difference in the control group. And the differences in both groups after depending the inspiratory muscle training were significantly found in the tests of TIS and 6MW test [Conclusion] The results showed that the inspiratory muscle training in stroke patients are correlated with the trunk stability and locomotion ability, suggesting that physical therapist must take into consideration the inspiratory muscle training, as well as functional training to improve physical function in stroke patients.

  19. Absence of insulin signalling in skeletal muscle is associated with reduced muscle mass and function: evidence for decreased protein synthesis and not increased degradation.

    Science.gov (United States)

    O'Neill, Elaine D; Wilding, John P H; Kahn, C Ronald; Van Remmen, Holly; McArdle, Anne; Jackson, Malcolm J; Close, Graeme L

    2010-06-01

    Loss of skeletal muscle mass and function is observed in many insulin-resistant disease states such as diabetes, cancer cachexia, renal failure and ageing although the mechanisms for this remain unclear. We hypothesised that impaired insulin signalling results in reduced muscle mass and function and that this decrease in muscle mass and function is due to both increased production of atrogenes and aberrant reactive oxygen species (ROS) generation. Maximum tetanic force of the extensor digitorum longus of muscle insulin receptor knockout (MIRKO) and lox/lox control mice was measured in situ. Muscles were removed for the measurement of mass, histological examination and ROS production. Activation of insulin signalling pathways, markers of muscle atrophy and indices of protein synthesis were determined in a separate group of MIRKO and lox/lox mice 15 min following treatment with insulin. Muscles from MIRKO mice had 36% lower maximum tetanic force generation compared with muscles of lox/lox mice. Muscle fibres of MIRKO mice were significantly smaller than those of lox/lox mice with no apparent structural abnormalities. Muscles from MIRKO mice demonstrated absent phosphorylation of AKT in response to exogenous insulin along with a failure to phosphorylate ribosomal S6 compared with lox/lox mice. Atrogin-1 and MuRF1 relative mRNA expression in muscles from MIRKO mice were decreased compared with muscles from lox/lox mice following insulin treatment. There were no differences in markers of reactive oxygen species damage between muscles from MIRKO mice and lox/lox mice. These data support the hypothesis that the absence of insulin signalling contributes to reduced muscle mass and function though decreased protein synthesis rather than proteasomal atrophic pathways.

  20. Small differences in Drosophila tropomyosin expression have significant effects on muscle function

    Energy Technology Data Exchange (ETDEWEB)

    Tansey, T.; Miller, R.C. (Univ. of Illinois, Chicago (United States)); Schultz, J.R.; Storti, R.V. (Georgetown Univ., Washington, DC (United States))

    1991-12-01

    The effects of promoter deletions on Drosophila tropomyosin I (TmI) gene expression have been determined by measuring TmI RNA levels in transformed flies. Decreases in RNA levels have been correlated with rescue of flightless and jumpless mutant phenotypes in Ifm(3)3 mutant transformed flies and changes in muscle ultrastructure. The results of this analysis have allowed us to identify a region responsible for 20% of maximal TmI expression, estimate threshold levels of TmI RNA required for indirect flight and jump muscle function, and obtain evidence suggesting that sarcomere length may be an important determinant of flight muscle functions.

  1. Roles of the troponin isoforms during indirect flight muscle ...

    Indian Academy of Sciences (India)

    Troponin proteins in cooperative interaction with tropomyosin are responsible for controlling the contraction of the striated muscles in response to changes in the intracellular calcium concentration. Contractility of the muscle is determined by the constituent protein isoforms, and the isoforms can switch over from one form to ...

  2. Association between selenium plasma levels and muscle function in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Milena B Stockler-Pinto

    2012-06-01

    Full Text Available Selenium (Se is a well-known antioxidant with a critical role in the proper functioning of nervous and muscle functions. In the last decade, many authors have suggested that Se may be a potent protective agent for neurons and myocytes through selenoprotein expression in the brain, as well as in skeletal and cardiac muscles. Low Se status has been associated with reduced coordination, motor speed and muscle strength. Reduced muscle function is common in hemodialysis (HD patients; however, no study evaluated the association between muscle function and Se levels in HD patients. The objective of this study was to correlate muscle function with Se plasma levels in HD patients. Twenty HD patients (12 men, 54.5±15.2 yr; 81.7±52.8 months on HD from RenalCor Clinic at Rio de Janeiro, Brazil were studied. Blood samples were collected during fasting, before a regular HD session. The Se plasma levels were determined by atomic absorption spectrophotometry with hydride generation (Hitachi, Z-500 and handgrip strength (HGS was measured three times with a mechanical dynamometer (Jamar after HD sessions in the non-fistula side and the highest value was used for analysis. HGS values less than the 10th percentile of an age-, gender- and regional specific reference were considered as muscle function loss. Plasma Se levels (31.9±14.8 μg/L were below the normal range (60-120 μg/L and all patients were Se deficient. HGS values were significantly greater in males (31.0±11.5 kg vs 14.0±6.8 kg for females (p=0.001 and the muscle function loss was observed in 50% of patients and, those with muscle function loss presented low Se levels (26.5±12.1 μg/L when compared to patients with preserved muscle function (39.12±14.5 μg/L (p=0.05. These data suggest that Se can have an important role on muscle function in HD patients. However, more research is needed to better understand this possible relationship in CKD patients.

  3. Impact of Pseudomonas aeruginosa Infection on Respiratory Muscle Function in Adult Cystic Fibrosis Patients.

    Science.gov (United States)

    Magnet, Friederike Sophie; Callegari, Jens; Dieninghoff, Doris; Spielmanns, Marc; Storre, Jan Hendrik; Schmoor, Claudia; Windisch, Wolfram

    2017-01-01

    Pseudomonas aeruginosa infection impairs respiratory muscle function in adolescents with cystic fibrosis, but its impact on adult patients has not been characterised. To investigate respiratory muscle function in adult cystic fibrosis patients according to P. aeruginosa status (repetitive samples over 12 months). The pressure-time index of the respiratory muscles (PTImus), a measure of their efficiency, served as the primary outcome. In addition, respiratory load and maximal respiratory muscle strength were assessed. In 51 patients examined (65% female; median age 32 years, IQR 24-40), a median of 3.0 (IQR 2-4) different pathogens was found in each patient. The PTImus was 0.113 and 0.126 in Pseudomonas-positive (n = 33) and -negative (n = 18) patients, respectively (p = 0.53). Univariate analysis showed a lower PTImus in male than in female patients (p = 0.006). Respiratory muscle load and strength were otherwise comparable, with the exception of higher nasal sniff pressures in Pseudomonas-positive patients who were chronically infected (>50% of positive samples). Quality of Life (according to the Cystic Fibrosis Questionnaire-Revised) was higher if both respiratory load and the PTImus were low (high respiratory muscle efficiency). Chronic P. aeruginosa infection does not influence respiratory muscle efficiency in adult cystic fibrosis patients with otherwise multiple co-infections. In addition, patients with reduced respiratory muscle efficiency had worse Quality of Life. © 2016 S. Karger AG, Basel.

  4. Impact of functional appliances on muscle activity: a surface electromyography study in children.

    Science.gov (United States)

    Woźniak, Krzysztof; Piątkowska, Dagmara; Szyszka-Sommerfeld, Liliana; Buczkowska-Radlińska, Jadwiga

    2015-01-20

    Electromyography (EMG) is the most objective tool for assessing changes in the electrical activity of the masticatory muscles. The purpose of the study was to evaluate the tone of the masseter and anterior temporalis muscles in growing children before and after 6 months of treatment with functional removable orthodontic appliances. The sample conisted of 51 patients with a mean age 10.7 years with Class II malocclusion. EMG recordings were performed by using a DAB-Bluetooth instrument (Zebris Medical GmbH, Germany). Recordings were performed in mandibular rest position, during maximum voluntary contraction (MVC), and during maximum effort. The results of the study indicated that the electrical activity of the muscles in each of the clinical situations was the same in the group of girls and boys. The factor that determined the activity of the muscles was their type. In mandibular rest position and in MVC, the activity of the temporalis muscles was significantly higher that that of the masseter muscels. The maximum effort test indicated a higher fatigue in masseter than in temporalis muscles. Surface electromyography is a useful tool for monitoring muscle activity. A 6-month period of functional therapy resulted in changes in the activity of the masticatory muscles.

  5. Synaptic and functional linkages between spinal premotor interneurons and hand-muscle activity during precision grip

    Directory of Open Access Journals (Sweden)

    Tomohiko eTakei

    2013-04-01

    Full Text Available Grasping is a highly complex movement that requires the coordination of a number of hand joints and muscles. Previous studies showed that spinal premotor interneurons (PreM-INs in the primate cervical spinal cord have divergent synaptic effects on hand motoneurons and that they might contribute to hand-muscle synergies. However, the extent to which these PreM-IN synaptic connections functionally contribute to modulating hand-muscle activity is not clear. In this paper, we explored the contribution of spinal PreM-INs to hand-muscle activation by quantifying the synaptic linkage (SL and functional linkage (FL of the PreM-INs with hand-muscle activities. The activity of 23 PreM-INs was recorded from the cervical spinal cord (C6–T1, with EMG signals measured simultaneously from hand and arm muscles in two macaque monkeys performing a precision grip task. Spike-triggered averages (STAs of rectified EMGs were compiled for 456 neuron–muscle pairs; 63 pairs showed significant post-spike effects (i.e., SL. Conversely, 231 of 456 pairs showed significant cross-correlations between the IN firing rate and rectified EMG (i.e., FL. Importantly, a greater proportion of the neuron–muscle pairs with SL showed FL (43/63 pairs, 68% compared with the pairs without SL (203/393, 52%, and the presence of SL was significantly associated with that of FL. However, a significant number of pairs had SL without FL (SL∩!FL, n = 20 or FL without SL (!SL∩FL, n = 203, and the proportions of these incongruities exceeded the number expected by chance. These results suggested that spinal PreM-INs function to significantly modulate hand-muscle activity during precision grip, but the contribution of other neural structures is also needed to recruit an adequate combination of hand-muscle motoneurons.

  6. Impact of Resistance Training on Skeletal Muscle Mitochondrial Biogenesis, Content, and Function

    Directory of Open Access Journals (Sweden)

    Thomas Groennebaek

    2017-09-01

    Full Text Available Skeletal muscle metabolic and contractile properties are reliant on muscle mitochondrial and myofibrillar protein turnover. The turnover of these specific protein pools is compromised during disease, aging, and inactivity. Oppositely, exercise can accentuate muscle protein turnover, thereby counteracting decay in muscle function. According to a traditional consensus, endurance exercise is required to drive mitochondrial adaptations, while resistance exercise is required to drive myofibrillar adaptations. However, concurrent practice of traditional endurance exercise and resistance exercise regimens to achieve both types of muscle adaptations is time-consuming, motivationally demanding, and contended to entail practice at intensity levels, that may not comply with clinical settings. It is therefore of principle interest to identify effective, yet feasible, exercise strategies that may positively affect both mitochondrial and myofibrillar protein turnover. Recently, reports indicate that traditional high-load resistance exercise can stimulate muscle mitochondrial biogenesis and mitochondrial respiratory function. Moreover, fatiguing low-load resistance exercise has been shown capable of promoting muscle hypertrophy and expectedly entails greater metabolic stress to potentially enhance mitochondrial adaptations. Consequently, fatiguing low-load resistance exercise regimens may possess the ability to stimulate muscle mitochondrial adaptations without compromising muscle myofibrillar accretion. However, the exact ability of resistance exercise to drive mitochondrial adaptations is debatable, not least due to some methodological challenges. The current review therefore aims to address the evidence on the effects of resistance exercise on skeletal muscle mitochondrial biogenesis, content and function. In prolongation, a perspective is taken on the specific potential of low-load resistance exercise on promoting mitochondrial adaptations.

  7. Functional and Volumetric Analysis of the Pectoralis Major Muscle After Submuscular Breast Augmentation.

    Science.gov (United States)

    Roxo, Ana Claudia; Nahas, Fabio Xerfan; Pinheiro Rodrigues, Nadia Cristina; Salles, José Inácio; Amaral Cossich, Victor Rodrigues; de Castro, Claudio Cardoso; Aboudib, Jose Horacio; Marques, Ruy Garcia

    2017-06-01

    Dual plane breast augmentation is a technical variation of the submuscular plane described as a technique that reduces contour deformities due to contraction of the pectoralis major muscle and lower risk of double-bubble deformity associated with breast ptosis. Despite improvement in the aesthetic aspect, there is still no consensus whether this technique affects the function of the pectoralis major muscle. The aim of this study was to correlate functional with volumetric changes associated with dissection of the muscle origin in submuscular breast augmentation. Thirty women who desired to undergo breast augmentation were selected prospectively and randomly allocated to 2 groups: 10 patients in the control group and 20 patients in the interventional group, who underwent submuscular breast augmentation. Magnetic resonance imaging and volumetric software were used to assess muscle volume and isokinetic dynamometry was used to assess function of the pectoralis major muscle. Preoperative measurements were compared with those at 3, 6, and 12 months after surgery. Magnetic resonance imaging revealed significant decrease in muscle volume at 6 and 12 months follow-up. The isokinetic test conducted during adduction showed a significant difference in muscle strength between groups from baseline to the 12-month follow-up, and between the 3- and 12-month follow-up. No significant differences in muscle strength during abduction were observed from baseline to the 3-, 6-, and 12-month follow-up. Submuscular breast augmentation reduced muscle strength during adduction 12 months after surgery, but without a significant correlation with volumetric muscle loss. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

  8. Prediction of muscle strength and postoperative function after knee flexor muscle resection for soft tissue sarcoma of the lower limbs.

    Science.gov (United States)

    Tanaka, A; Yoshimura, Y; Aoki, K; Okamoto, M; Kito, M; Suzuki, S; Takazawa, A; Ishida, T; Kato, H

    2017-11-01

    Oncological margins and prognosis are the most important factors for operative planning of soft tissue sarcomas, but prediction of postoperative function is also necessary. The purpose of this study was to predict the knee flexion strength and postoperative function after knee flexor muscle resection for soft tissue sarcoma of the lower limbs. Seventeen patients underwent knee flexor muscle resection for soft tissue sarcoma of the lower limbs between 1991 and 2015. The type of resected muscles was surveyed, knee flexion strength (ratio of affected to unaffected side) was evaluated using the Biodex System isokinetic dynamometer, and differences between the type of resected muscles were examined. The Musculoskeletal Tumor Society (MSTS) score, Toronto Extremity Salvage Score (TESS), European Quality of Life-5 Dimensions (EQ-5D), and Short Form 8 (SF-8) were used to assess postoperative function and examine correlations with flexion strength. The cutoff value for flexion strength to predict good postoperative results was calculated by a receiver operating characteristic (ROC) curve and Fisher's exact test. Median flexion strength decreased in the resection of sartorius (97.8%), gracilis (95.4%), gastrocnemius (85.2%; interquartile range (IQR): 85.0-86.2), medial hamstrings (semimembranosus and semitendinosus, 76.2%; IQR: 73.3-78.0), lateral hamstrings (long and short head of biceps femoris, 66.1%; IQR: 65.9-70.4), and bilateral hamstrings (27.3%; IQR: 26.6-31.5). A significant difference was observed between lateral and bilateral hamstrings resection (P=0.049). Flexion strength was associated with lower functional scales (MSTS score, P=0.021; TESS, P=0.008; EQ-5D, P=0.034). Satisfactory function was obtained at a flexion strength cutoff value of 65.7%, and strength remained above the cutoff value up to unilateral hamstrings resection. Greater knee flexor muscles resection can result in functional deficits that are associated with decreased flexion strength. If

  9. Effects of Functional Training Program in Core Muscles in Women with Fibromyalgia

    Directory of Open Access Journals (Sweden)

    Iván Darío Pinzón-Ríos

    2015-01-01

    Full Text Available Abstract: Objective: To evaluate the effects of a program of functional muscles core training targeting women with fibromyalgia. Materials and methods: A quasi-experimental type trial was conducted, before and after an intervention, for 20 days, often three days/week, 60 minutes each session. In a single-group of eight women, changes in muscle strength, pain, quality of life related to health and physical activity were evaluated. Results: An increase in repetitions of the test trunk flexion, time on the left and right bridge testing lateral and prone bridge the test were found. All features of pain decreased, and, according to the S-FIQ, a decrease in morning fatigue, stiffness and anxiety was reported. Also Met’s/minute-weeks increased after intervention. Conclusion: These data suggest that functional program core muscle training is effective in increasing muscle strength, pain modulation, functional performance optimization, and increased levels of physical activity in women with fibromyalgia.

  10. Measurement of abdominal muscle thickness using M-mode ultrasound imaging during functional activities.

    Science.gov (United States)

    Bunce, Steve M; Hough, Alan D; Moore, Ann P

    2004-02-01

    Ultrasound imaging has been previously utilized in the measurement of muscle thickness and cross-sectional area in research studies, and advocated as a clinical biofeedback tool in the rehabilitation of transversus abdominis function following episodes of low back pain. This paper describes how the thickness of the abdominal muscles can be quantified with a new measurement technique using M-mode ultrasound. The technique uses a custom-made transducer holder that facilitates measurement of muscle thickness changes during functional activity. Limitations of the technique and potential future applications are discussed. The M-mode ultrasound technique may provide an effective method for the non-invasive measurement of abdominal muscle thickness during functional activities.

  11. Effects of functional exercise training on performance and muscle strength after meniscectomy

    DEFF Research Database (Denmark)

    Ericsson, Y B; Dahlberg, L E; Roos, E M

    2008-01-01

    Muscular deficits and functional limitations have been found years after meniscectomy of the knee. The purpose of this randomized controlled trial was to examine the effect of functional exercise training on functional performance and isokinetic thigh muscle strength in middle-aged patients...... subsequent to meniscectomy for a degenerative tear. Four years after meniscectomy, 45 patients (29 men, 16 women) were randomized to functional exercise training, supervised by a physical therapist, three times weekly for 4 months or to no intervention. The exercise program comprised of postural stability...... training and functional strength and endurance exercises for leg and trunk muscles. Outcomes were three functional performance tests and isokinetic muscle strength. Thirty patients (16 exercisers/14 controls) completed the study. Compared with control patients, the exercise group showed significant...

  12. Insulin resistance and mitochondrial function in skeletal muscle

    DEFF Research Database (Denmark)

    Dela, Flemming; Helge, Jørn Wulff

    2013-01-01

    are used in the attempt to resolve the mechanisms of insulin resistance. In this context, a dysfunction of mitochondria in the skeletal muscle has been suggested to play a pivotal role. It has been postulated that a decrease in the content of mitochondria in the skeletal muscle can explain the insulin...... resistance. Complementary to this also specific defects of components in the respiratory chain in the mitochondria have been suggested to play a role in insulin resistance. A key element in these mechanistic suggestions is inability to handle substrate fluxes and subsequently an accumulation of ectopic...... intramyocellular lipids, interfering with insulin signaling. In this review we will present the prevailing view-points and argue for the unlikelihood of this scenario being instrumental in human insulin resistance. This article is part of a Directed Issue entitled: Bioenergetic dysfunction....

  13. Functional and morphological effects of resistance exercise on disuse-induced skeletal muscle atrophy

    Directory of Open Access Journals (Sweden)

    H. Nicastro

    2011-11-01

    Full Text Available Abstract The reduction of skeletal muscle loss in pathological states, such as muscle disuse, has considerable effects in terms of rehabilitation and quality of life. Since there is no currently effective and safe treatment available for skeletal muscle atrophy, the search for new alternatives is necessary. Resistance exercise (RE seems to be an important tool in the treatment of disuse-induced skeletal muscle atrophy by promoting positive functional (strength and power and structural (hypertrophy and phenotypic changes adaptive responses. Human and animal studies using different types of resistance exercise (flywheel, vascular occlusion, dynamic, isometric, and eccentric have obtained results of great importance. However, since RE is a complex phenomenon, lack of strict control of its variables (volume, frequency, intensity, muscle action, rest intervals limits the interpretation of the impact of the manipulation on skeletal muscle remodeling and function under disuse. The aim of this review is to critically describe the functional and morphological role of resistance exercise in disuse-induced skeletal muscle atrophy with emphasis on the principles of training.

  14. Architectural design of the pelvic floor is consistent with muscle functional subspecialization.

    Science.gov (United States)

    Tuttle, Lori J; Nguyen, Olivia T; Cook, Mark S; Alperin, Marianna; Shah, Sameer B; Ward, Samuel R; Lieber, Richard L

    2014-02-01

    Skeletal muscle architecture is the strongest predictor of a muscle's functional capacity. The purpose of this study was to define the architectural properties of the deep muscles of the female pelvic floor (PFMs) to elucidate their structure-function relationships. PFMs coccygeus (C), iliococcygeus (IC), and pubovisceral (PV) were harvested en bloc from ten fixed human cadavers (mean age 85 years, range 55-102). Fundamental architectural parameters of skeletal muscles [physiological cross-sectional area (PCSA), normalized fiber length, and sarcomere length (L(s))] were determined using validated methods. PCSA predicts muscle-force production, and normalized fiber length is related to muscle excursion. These parameters were compared using repeated measures analysis of variance (ANOVA) with post hoc t tests, as appropriate. Significance was set to α = 0.05. PFMs were thinner than expected based on data reported from imaging studies and in vivo palpation. Significant differences in fiber length were observed across PFMs: C = 5.29 ± 0.32 cm, IC = 7.55 ± 0.46 cm, PV = 10.45 ± 0.67 cm (p design shows individual muscles demonstrating differential architecture, corresponding to specialized function in the pelvic floor.

  15. Effects of Ramadan Fasting on Inspiratory Muscle Function.

    Science.gov (United States)

    Soori, Mohsen; Mohaghegh, Shahram; Hajain, Maryam; Moraadi, Behrooz

    2016-09-01

    Ramadan fasting is a major challenge for exercising Muslims especially in warm seasons. There is some evidence to indicate that Ramadan fasting causes higher subjective ratings of perceived exertion (RPE) in fasting Muslims. The mechanisms of this phenomenon are not known exactly. The role of respiratory muscle strength in this regard has not been studied yet. The aim of this study was investigation of the effects of Ramadan fasting on respiratory muscle strength. In a before-after study, from 35 fasting, apparently healthy, male adults who had fasted from the beginning of Ramadan, maximal inspiratory muscle pressure (MIP) and peak inspiratory flow (PIF) were measured in the last week of Ramadan month in summer. At the time of test, there was not any sleep problem in participants and all of them had good cooperation. Three months later, after exclusion of incompatible persons mainly because of change in their physical activity level, smoking behavior or drug consumption, the measurements were repeated in 12 individuals. Weight, MIP and PIF data had normal distribution (Kolmogorov-Smirnov Test). There was a significant increase in MIP (mean 8.3 cm H 2 O with 95% confidence interval of 2.2 - 14.3) and PIF (mean 0.55 lit/s with 95% confidence interval of 0.02 - 1.07) and weight (mean 3.4 Kg with 95% confidence interval of 2.2 - 4.5) after Ramadan (Paired t test with P Ramadan fasting may cause reduction of respiratory muscle strength through reduction of body weight.

  16. Functional alteration of breast muscle fatty acid profile by ...

    African Journals Online (AJOL)

    Breast muscle fatty acid (FA) profile was studied in broiler chickens fed at different levels of n-6:n-3 polyunsaturated fatty acid (PUFA) ratios in 4 treatment groups; very high level of n-6:n-3 ratios (VH), high level of n-6:n-3 ratios (H), low level of n-6:n-3 ratios (L), very low level of n-6:n-3 ratios (VL) and control, respectively.

  17. Cold water immersion enhances recovery of submaximal muscle function after resistance exercise.

    Science.gov (United States)

    Roberts, Llion A; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

    2014-10-15

    We investigated the effect of cold water immersion (CWI) on the recovery of muscle function and physiological responses after high-intensity resistance exercise. Using a randomized, cross-over design, 10 physically active men performed high-intensity resistance exercise followed by one of two recovery interventions: 1) 10 min of CWI at 10°C or 2) 10 min of active recovery (low-intensity cycling). After the recovery interventions, maximal muscle function was assessed after 2 and 4 h by measuring jump height and isometric squat strength. Submaximal muscle function was assessed after 6 h by measuring the average load lifted during 6 sets of 10 squats at 80% of 1 repetition maximum. Intramuscular temperature (1 cm) was also recorded, and venous blood samples were analyzed for markers of metabolism, vasoconstriction, and muscle damage. CWI did not enhance recovery of maximal muscle function. However, during the final three sets of the submaximal muscle function test, participants lifted a greater load (P work during subsequent training sessions, which could enhance long-term training adaptations. Copyright © 2014 the American Physiological Society.

  18. Human lung mast cells modulate the functions of airway smooth muscle cells in asthma.

    Science.gov (United States)

    Alkhouri, H; Hollins, F; Moir, L M; Brightling, C E; Armour, C L; Hughes, J M

    2011-09-01

    Activated mast cell densities are increased on the airway smooth muscle in asthma where they may modulate muscle functions and thus contribute to airway inflammation, remodelling and airflow obstruction. To determine the effects of human lung mast cells on the secretory and proliferative functions of airway smooth muscle cells from donors with and without asthma. Freshly isolated human lung mast cells were stimulated with IgE/anti-IgE. Culture supernatants were collected after 2 and 24 h and the mast cells lysed. The supernatants/lysates were added to serum-deprived, subconfluent airway smooth muscle cells for up to 48 h. Released chemokines and extracellular matrix were measured by ELISA, proliferation was quantified by [(3) H]-thymidine incorporation and cell counting, and intracellular signalling by phospho-arrays. Mast cell 2-h supernatants reduced CCL11 and increased CXCL8 and fibronectin production from both asthmatic and nonasthmatic muscle cells. Leupeptin reversed these effects. Mast cell 24-h supernatants and lysates reduced CCL11 release from both muscle cell types but increased CXCL8 release by nonasthmatic cells. The 24-h supernatants also reduced asthmatic, but not nonasthmatic, muscle cell DNA synthesis and asthmatic cell numbers over 5 days through inhibiting extracellular signal-regulated kinase (ERK) and phosphatidylinositol (PI3)-kinase pathways. However, prostaglandins, thromboxanes, IL-4 and IL-13 were not involved in reducing the proliferation. Mast cell proteases and newly synthesized products differentially modulated the secretory and proliferative functions of airway smooth muscle cells from donors with and without asthma. Thus, mast cells may modulate their own recruitment and airway smooth muscle functions locally in asthma. © 2011 John Wiley & Sons A/S.

  19. Enzymatically modified isoquercitrin supplementation intensifies plantaris muscle fiber hypertrophy in functionally overloaded mice.

    Science.gov (United States)

    Kohara, Akiko; Machida, Masanao; Setoguchi, Yuko; Ito, Ryouichi; Sugitani, Masanori; Maruki-Uchida, Hiroko; Inagaki, Hiroyuki; Ito, Tatsuhiko; Omi, Naomi; Takemasa, Tohru

    2017-01-01

    Enzymatically modified isoquercitrin (EMIQ) is produced from rutin using enzymatic hydrolysis followed by treatment with glycosyltransferase in the presence of dextrin to add glucose residues. EMIQ is absorbed in the same way as quercetin, a powerful antioxidant reported to prevent disused muscle atrophy by targeting mitochondria and to have ergogenic effects. The present study investigated the effect of EMIQ on skeletal muscle hypertrophy induced by functional overload. In Study 1, 6-week-old ICR male mice were divided into 4 groups: sham-operated control, sham-operated EMIQ, overload-operated control, and overload-operated EMIQ groups. In Study 2, mice were divided into 3 groups: overload-operated whey control, overload-operated whey/EMIQ (low dose), and overload-operated whey/EMIQ (high dose) groups. The functional overload of the plantaris muscle was induced by ablation of the synergist (gastrocnemius and soleus) muscles. EMIQ and whey protein were administered with food. Three weeks after the operation, the cross-sectional area and minimal fiber diameter of the plantaris muscle fibers were measured. In Study 1, functional overload increased the cross-sectional area and minimal fiber diameter of the plantaris muscle. EMIQ supplementation significantly increased the cross-sectional area and minimal fiber diameter of the plantaris muscle in both the sham-operated and overload-operated groups. In Study 2, EMIQ supplementation combined with whey protein administration significantly increased the cross-sectional area and minimal fiber diameter of the plantaris muscle. EMIQ, even when administered as an addition to whey protein supplementation, significantly intensified the fiber hypertrophy of the plantaris muscle in functionally overloaded mice. EMIQ supplementation also induced fiber hypertrophy of the plantaris in sham-operated mice.

  20. [Free functional gracilis muscle transplantation for reconstruction of active elbow flexion in posttraumatic brachial plexus lesions].

    Science.gov (United States)

    Berger, Alfred; Hierner, Robert

    2009-06-01

    Reconstruction of powerful active elbow flexion. Reconstruction of missing muscle unit by neurovascular pedicled functional muscle transplantation. Treatment of last choice for --secondary reconstruction of active elbow flexion in case of complete lesion of the brachial plexus or musculocutaneous nerve (M0 muscle function = replacement indication), partial but incomplete lesion of the brachial plexus or musculocutaneous nerve (M1-(3) muscle function = augmentation indication); --replacement of the elbow flexor muscles in case of primary muscle loss (tumor, trauma). Concomitant lesions of the axillary artery. No adequate donor nerve. Relative: no sensibility at all at the forearm and hand. Free functional biarticular myocutaneous transplantation of gracilis muscle. A myocutaneous gracilis flap is raised at the thigh. At the upper arm the flap is fixed proximally to the coracoid process or the lateral clavicle. The distal insertion is sutured to the distal biceps tendon. Vascular anastomoses are carried out in end-to-side fashion with the brachial artery and vein. Nerval coaptation is done in end-to-end technique using the muculocutaneous nerve. Complete immobilization for 6 weeks. Dorsal upper arm splint until sufficient muscle power (M(4)). Progressive increase of active range of motion for another 6 weeks. Continuation of physiotherapy for 12-18 months. Postoperative standardized compression therapy, combined with scar therapy (silicone sheet). Functionally useful results can be expected in 60-75% of patients, especially if there is some residual function (M1 or M2) left ("augmentation indication"). Early free functional muscle transplantation shows best results in patients with direct muscle defect, because all vascular and neuronal structures are still available, and no secondary changes such as fibrosis or joint stiffness are present yet. There are inconsistent results for patients with neurologic insufficiency (i.e., total brachial plexus palsy) or mixed

  1. New function of the myostatin/activin type I receptor (ALK4) as a mediator of muscle atrophy and muscle regeneration

    Science.gov (United States)

    Pasteuning-Vuhman, Svitlana; Boertje-van der Meulen, Johanna W.; van Putten, Maaike; Overzier, Maurice; ten Dijke, Peter; Kiełbasa, Szymon M.; Arindrarto, Wibowo; Wolterbeek, Ron; Lezhnina, Ksenia V.; Ozerov, Ivan V.; Aliper, Aleksandr M.; Hoogaars, Willem M.; Aartsma-Rus, Annemieke; Loomans, Cindy J. M.

    2017-01-01

    Skeletal muscle fibrosis and impaired muscle regeneration are major contributors to muscle wasting in Duchenne muscular dystrophy (DMD). Muscle growth is negatively regulated by myostatin (MSTN) and activins. Blockage of these pathways may improve muscle quality and function in DMD. Antisense oligonucleotides (AONs) were designed specifically to block the function of ALK4, a key receptor for the MSTN/activin pathway in skeletal muscle. AON-induced exon skipping resulted in specific Alk4 down-regulation, inhibition of MSTN activity, and increased myoblast differentiation in vitro. Unexpectedly, a marked decrease in muscle mass (10%) was found after Alk4 AON treatment in mdx mice. In line with in vitro results, muscle regeneration was stimulated, and muscle fiber size decreased markedly. Notably, when Alk4 was down-regulated in adult wild-type mice, muscle mass decreased even more. RNAseq analysis revealed dysregulated metabolic functions and signs of muscle atrophy. We conclude that ALK4 inhibition increases myogenesis but also regulates the tight balance of protein synthesis and degradation. Therefore, caution must be used when developing therapies that interfere with MSTN/activin pathways.—Pasteuning-Vuhman, S., Boertje-van der Meulen, J. W., van Putten, M., Overzier, M., ten Dijke, P., Kiełbasa, S. M., Arindrarto, W., Wolterbeek, R., Lezhnina, K. V., Ozerov, I. V., Aliper, A. M., Hoogaars, W. M., Aartsma-Rus, A., Loomans, C. J. M. New function of the myostatin/activin type I receptor (ALK4) as a mediator of muscle atrophy and muscle regeneration. PMID:27733450

  2. Effect of physical training on function of chronically painful muscles: A randomized controlled trial

    DEFF Research Database (Denmark)

    Andersen, Lars L; Andersen, Christoffer H; Zebis, Mette K

    2008-01-01

    Purpose: Pain and tenderness of the upper trapezius muscle is frequent in several occupational groups. The objective of this study is to investigate the effect of three contrasting interventions on muscle function and pain in women with trapezius myalgia. Methods: A group of employed women (n=42......) with a clinical diagnosis of trapezius myalgia participated in a 10 week randomized controlled intervention; specific strength training of the neck/shoulder muscles (SST), general fitness training performed as leg-bicycling (GFT), or a reference intervention without physical activity (REF). Torque...... during the reference contraction decreased significantly for both the trapezius and deltoid muscles (Ptraining relieves pain and increases maximal activity specifically of the painful trapezius muscle, leading to increased shoulder abduction strength...

  3. Neck muscle function in violinists/violists with and without neck pain.

    Science.gov (United States)

    Steinmetz, Anke; Claus, Andrew; Hodges, Paul W; Jull, Gwendolen A

    2016-04-01

    Neck pain is associated with changes in neuromuscular control of cervical muscles. Violin and viola playing requires good function of the flexor muscles to stabilize the instrument. This study investigated the flexor muscle behaviour in violin/viola players with and without neck pain using the craniocervical flexion test (CCFT). In total, 12 violin/viola players with neck pain, 21 violin/viola players without neck pain in the preceding 12 weeks and 21 pain-free non-musicians were included. Activity of the sternocleidomastoid muscles (SCM) was measured with surface electromyography (EMG) during the CCFT. Violin/viola players with neck pain displayed greater normalised SCM EMG amplitudes during CCFT than the pain-free musicians and non-musicians (P neck pain in violinists/violists is associated with altered behaviour of the superficial neck flexor muscles consistent with neck pain, despite the specific use of the deep and superficial neck flexors during violin playing.

  4. Direct observation of syringeal muscle function in songbirds and a parrot

    DEFF Research Database (Denmark)

    Larsen, Ole Næsbye; Goller, Franz

    2002-01-01

    . In parrots (cockatiels, Nymphicus hollandicus), direct observations show that even during quiet respiration the lateral tympaniform membranes (LTMs) are partially adducted into the tracheal lumen to form a narrow slot. Contraction of the superficial intrinsic muscle, m. syringealis superficialis, adducts......The role of syringeal muscles in controlling the aperture of the avian vocal organ, the syrinx, was evaluated directly for the first time by observing and filming through an endoscope while electrically stimulating different muscle groups of anaesthetised birds. In songbirds (brown thrashers......, Toxostoma rufum, and cardinals, Cardinalis cardinalis), direct observations of the biomechanical effects of contraction largely confirm the functions of the intrinsic syringeal muscles proposed from indirect studies. Contraction of the dorsal muscles, m. syringealis dorsalis (dS) and m. tracheobronchialis...

  5. Correlation between pulmonary functions and respiratory muscle activity in patients with forward head posture.

    Science.gov (United States)

    Kang, Jeong-Il; Jeong, Dae-Keun; Choi, Hyun

    2018-01-01

    [Purpose] The purpose of this study is to determine the effect that secondary postural deformities and chronic postural abnormalities have on lung capacity, as well as correlate the activity of the respiratory muscles. The results provide basic objective data about the forward head posture and respiratory muscle activity that can be used in clinical situations. [Subjects and Methods] The subjects used in this study were 24 patients aged 25 to 35 years old who visited a hospital in Jeollanam-do Province, Korea, between September 2015 and January 2016. The patients were diagnosed with forward head posture because the vertical line between the acromion process and the external acoustic meatus was at least 5 cm. We measured the craniovertebral angle, pulmonary functions, and respiratory muscle activity of the subjects for correlation analysis. [Results] A positive correlation was found between the craniovertebral angle and the forced vital capacity (r=0.63), while a negative correlation was found between the craniovertebral angle and the sternocleidomastoid muscle (r=-0.77). The craniovertebral angle and the anterior scalene muscle showed a negative correlation (r=-0.65). There were positive correlations between the forced vital capacity and the sternocleidomastoid muscle (r=0.71), and between the forced vital capacity and the anterior scalene muscle (r=0.59). [Conclusion] Severe forward head posture increased the activities of the sternocleidomastoid muscles and the anterior scalene muscles, and decreased the forced vital capacity. Thus, it is necessary to develop more efficient interventions for managing forward head posture based on pulmonary function and the activity of the respiratory synergist muscles.

  6. Functional Segregation within the Muscles of Aquatic Propulsion in the Asiatic Water Monitor (Varanus salvator

    Directory of Open Access Journals (Sweden)

    Bruce Arthur Young

    2016-09-01

    Full Text Available Water monitor lizards (Varanus salvator swim using sinusoidal oscillations generated at the base of their long (50% of total body length tail. In an effort to determine which level of the structural/organizational hierarchy of muscle is associated with functional segregation between the muscles of the tail base, an array of muscle features — myosin heavy chain profiles, enzymatic fiber types, twitch and tetanic force production, rates of fatigue, muscle compliance, and electrical activity patterns — were quantitated. The two examined axial muscles, longissimus and iliocaudalis, were generally similar at the molecular, biochemical, and physiological levels, but differed at the biomechanics level and in their activation pattern. The appendicular muscle examined, caudofemoralis, differed from the axial muscles particularly at the molecular and physiological levels, and it exhibited a unique compliance profile and pattern of electrical activation. There were some apparent contradictions between the different structural/organizational levels examined. These contradictions, coupled with a unique myosin heavy chain profile, lead to the hypothesis that there are previously un-described molecular/biochemical specializations within varanid skeletal muscles.

  7. β-Catenin gain of function in muscles impairs neuromuscular junction formation.

    Science.gov (United States)

    Wu, Haitao; Lu, Yisheng; Barik, Arnab; Joseph, Anish; Taketo, Makoto Mark; Xiong, Wen-Cheng; Mei, Lin

    2012-07-01

    Neuromuscular junction (NMJ) formation requires proper interaction between motoneurons and muscle cells. β-Catenin is required in muscle cells for NMJ formation. To understand underlying mechanisms, we investigated the effect of β-catenin gain of function (GOF) on NMJ development. In HSA-β-cat(flox(ex3)/+) mice, which express stable β-catenin specifically in muscles, motor nerve terminals became extensively defasciculated and arborized. Ectopic muscles were observed in the diaphragm and were innervated by ectopic phrenic nerve branches. Moreover, extensive outgrowth and branching of spinal axons were evident in the GOF mice. These results indicate that increased β-catenin in muscles alters presynaptic differentiation. Postsynaptically, AChR clusters in HSA-β-cat(flox(ex3)/+) diaphragms were distributed in a wider region, suggesting that muscle β-catenin GOF disrupted the signal that restricts AChR clustering to the middle region of muscle fibers. Expression of stable β-catenin in motoneurons, however, had no effect on NMJ formation. These observations provide additional genetic evidence that pre- and postsynaptic development of the NMJ requires an intricate balance of β-catenin activity in muscles.

  8. Architectural design of the pelvic floor is consistent with muscle functional subspecialization

    Science.gov (United States)

    Tuttle, Lori J.; Nguyen, Olivia T.; Cook, Mark S.; Alperin, Marianna; Shah, Sameer B.; Ward, Samuel R.

    2014-01-01

    Introduction and hypothesis Skeletal muscle architecture is the strongest predictor of a muscle’s functional capacity. The purpose of this study was to define the architectural properties of the deep muscles of the female pelvic floor (PFMs) to elucidate their structure–function relationships. Methods PFMs coccygeus (C), iliococcygeus (IC), and pubovisceral (PV) were harvested en bloc from ten fixed human cadavers (mean age 85 years, range 55–102). Fundamental architectural parameters of skeletal muscles [physiological cross-sectional area (PCSA), normalized fiber length, and sarcomere length (Ls)] were determined using validated methods. PCSA predicts muscle-force production, and normalized fiber length is related to muscle excursion. These parameters were compared using repeated measures analysis of variance (ANOVA) with post hoc t tests, as appropriate. Significance was set to α=0.05. Results PFMs were thinner than expected based on data reported from imaging studies and in vivo palpation. Significant differences in fiber length were observed across PFMs: C=5.29±0.32 cm, IC=7.55±0.46 cm, PV=10.45±0.67 cm (pstabilizer. PV demonstrated the longest fibers, suggesting that it functions to produce large excursions. Conclusions PFM design shows individual muscles demonstrating differential architecture, corresponding to specialized function in the pelvic floor. PMID:23903821

  9. Muscle activity during functional coordination training: implications for strength gain and rehabilitation.

    Science.gov (United States)

    Jørgensen, Marie B; Andersen, Lars L; Kirk, Niels; Pedersen, Mogens T; Søgaard, Karen; Holtermann, Andreas

    2010-07-01

    The purpose of this study was to evaluate if different types, body positions, and levels of progression of functional coordination exercises can provide sufficiently high levels of muscle activity to improve strength of the neck, shoulder, and trunk muscles. Nine untrained women were familiarized with 7 functional coordination exercises 12 times during 4 weeks before testing. Surface electromyographic (EMG) activity was obtained from rectus abdominus, erector spinae, obliquus externus, and trapezius during the exercises with 2-4 levels of progression. Electromyography was normalized to the maximal EMG activity during maximal voluntary contractions, and a p value muscles reached sufficiently high levels of activity during the coordination exercises for strength gain (>60% of maximal EMG activity). Type of exercise played a significant role for the attained muscle activity. Body position during the exercises was important for the activity of the erector spinae, and level of progression was important for the activity of the trapezius. The findings indicate that depending on type, body position, and level of progression, functional coordination training can be performed with a muscle activity sufficient for strength gain. Functional coordination training may therefore be a good choice for prevention or rehabilitation of musculoskeletal pain or injury in the neck, shoulder, or trunk muscles.

  10. Characterization of the equine skeletal muscle transcriptome identifies novel functional responses to exercise training

    Directory of Open Access Journals (Sweden)

    MacHugh David E

    2010-06-01

    Full Text Available Abstract Background Digital gene expression profiling was used to characterize the assembly of genes expressed in equine skeletal muscle and to identify the subset of genes that were differentially expressed following a ten-month period of exercise training. The study cohort comprised seven Thoroughbred racehorses from a single training yard. Skeletal muscle biopsies were collected at rest from the gluteus medius at two time points: T1 - untrained, (9 ± 0.5 months old and T2 - trained (20 ± 0.7 months old. Results The most abundant mRNA transcripts in the muscle transcriptome were those involved in muscle contraction, aerobic respiration and mitochondrial function. A previously unreported over-representation of genes related to RNA processing, the stress response and proteolysis was observed. Following training 92 tags were differentially expressed of which 74 were annotated. Sixteen genes showed increased expression, including the mitochondrial genes ACADVL, MRPS21 and SLC25A29 encoded by the nuclear genome. Among the 58 genes with decreased expression, MSTN, a negative regulator of muscle growth, had the greatest decrease. Functional analysis of all expressed genes using FatiScan revealed an asymmetric distribution of 482 Gene Ontology (GO groups and 18 KEGG pathways. Functional groups displaying highly significant (P Conclusion Exercise training in Thoroughbred racehorses results in coordinate changes in the gene expression of functional groups of genes related to metabolism, oxidative phosphorylation and muscle structure.

  11. Extrapulmonary features of bronchiectasis: muscle function, exercise capacity, fatigue, and health status

    Directory of Open Access Journals (Sweden)

    Ozalp Ozge

    2012-06-01

    Full Text Available Abstract Background There are limited number of studies investigating extrapulmonary manifestations of bronchiectasis. The purpose of this study was to compare peripheral muscle function, exercise capacity, fatigue, and health status between patients with bronchiectasis and healthy subjects in order to provide documented differences in these characteristics for individuals with and without bronchiectasis. Methods Twenty patients with bronchiectasis (43.5 ± 14.1 years and 20 healthy subjects (43.0 ± 10.9 years participated in the study. Pulmonary function, respiratory muscle strength (maximal expiratory pressure – MIP - and maximal expiratory pressure - MEP, and dyspnea perception using the Modified Medical Research Council Dyspnea Scale (MMRC were determined. A six-minute walk test (6MWT was performed. Quadriceps muscle, shoulder abductor, and hand grip strength (QMS, SAS, and HGS, respectively using a hand held dynamometer and peripheral muscle endurance by a squat test were measured. Fatigue perception and health status were determined using the Fatigue Severity Scale (FSS and the Leicester Cough Questionnaire (LCQ, respectively. Results Number of squats, 6MWT distance, and LCQ scores as well as lung function testing values and respiratory muscle strength were significantly lower and MMRC and FSS scores were significantly higher in patients with bronchiectasis than those of healthy subjects (p p p p p  Conclusions Peripheral muscle endurance, exercise capacity, fatigue and health status were adversely affected by the presence of bronchiectasis. Fatigue was associated with dyspnea and health status. Respiratory muscle strength was related to peripheral muscle strength and health status, but not to fatigue, peripheral muscle endurance or exercise capacity. These findings may provide insight for outcome measures for pulmonary rehabilitation programs for patients with bronchiectasis.

  12. Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle function

    Science.gov (United States)

    Gallagher, Thomas L.; Arribere, Joshua A.; Geurts, Paul A.; Exner, Cameron R. T.; McDonald, Kent L.; Dill, Kariena K.; Marr, Henry L.; Adkar, Shaunak S.; Garnett, Aaron T.; Amacher, Sharon L.; Conboy, John G.

    2012-01-01

    Rbfox RNA binding proteins are implicated as regulators of phylogenetically-conserved alternative splicing events important for muscle function. To investigate the function of rbfox genes, we used morpholino-mediated knockdown of muscle-expressed rbfox1l and rbfox2 in zebrafish embryos. Single and double morphant embryos exhibited changes in splicing of overlapping sets of bioinformatically-predicted rbfox target exons, many of which exhibit a muscle-enriched splicing pattern that is conserved in vertebrates. Thus, conservation of intronic Rbfox binding motifs is a good predictor of Rbfox-regulated alternative splicing. Morphology and development of single morphant embryos was strikingly normal; however, muscle development in double morphants was severely disrupted. Defects in cardiac muscle were marked by reduced heart rate and in skeletal muscle by complete paralysis. The predominance of wavy myofibers and abnormal thick and thin filaments in skeletal muscle revealed that myofibril assembly is defective and disorganized in double morphants. Ultra-structural analysis revealed that although sarcomeres with electron dense M- and Z-bands are present in muscle fibers of rbfox1l/rbox2 morphants, they are substantially reduced in number and alignment. Importantly, splicing changes and morphological defects were rescued by expression of morpholino-resistant rbfox cDNA. Additionally, a target-blocking MO complementary to a single UGCAUG motif adjacent to an rbfox target exon of fxr1 inhibited inclusion in a similar manner to rbfox knockdown, providing evidence that Rbfox regulates the splicing of target exons via direct binding to intronic regulatory motifs. We conclude that Rbfox proteins regulate an alternative splicing program essential for vertebrate heart and skeletal muscle function. PMID:21925157

  13. Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions.

    Science.gov (United States)

    Gallagher, Thomas L; Arribere, Joshua A; Geurts, Paul A; Exner, Cameron R T; McDonald, Kent L; Dill, Kariena K; Marr, Henry L; Adkar, Shaunak S; Garnett, Aaron T; Amacher, Sharon L; Conboy, John G

    2011-11-15

    Rbfox RNA binding proteins are implicated as regulators of phylogenetically-conserved alternative splicing events important for muscle function. To investigate the function of rbfox genes, we used morpholino-mediated knockdown of muscle-expressed rbfox1l and rbfox2 in zebrafish embryos. Single and double morphant embryos exhibited changes in splicing of overlapping sets of bioinformatically-predicted rbfox target exons, many of which exhibit a muscle-enriched splicing pattern that is conserved in vertebrates. Thus, conservation of intronic Rbfox binding motifs is a good predictor of Rbfox-regulated alternative splicing. Morphology and development of single morphant embryos were strikingly normal; however, muscle development in double morphants was severely disrupted. Defects in cardiac muscle were marked by reduced heart rate and in skeletal muscle by complete paralysis. The predominance of wavy myofibers and abnormal thick and thin filaments in skeletal muscle revealed that myofibril assembly is defective and disorganized in double morphants. Ultra-structural analysis revealed that although sarcomeres with electron dense M- and Z-bands are present in muscle fibers of rbfox1l/rbox2 morphants, they are substantially reduced in number and alignment. Importantly, splicing changes and morphological defects were rescued by expression of morpholino-resistant rbfox cDNA. Additionally, a target-blocking MO complementary to a single UGCAUG motif adjacent to an rbfox target exon of fxr1 inhibited inclusion in a similar manner to rbfox knockdown, providing evidence that Rbfox regulates the splicing of target exons via direct binding to intronic regulatory motifs. We conclude that Rbfox proteins regulate an alternative splicing program essential for vertebrate heart and skeletal muscle functions. Published by Elsevier Inc.

  14. Effects of inspiratory muscle training on pulmonary function, respiratory muscle strength and functional capacity in patients with atrial fibrillation: a randomized controlled trial.

    Science.gov (United States)

    Zeren, Melih; Demir, Rengin; Yigit, Zerrin; Gurses, Hulya N

    2016-12-01

    To investigate the effects of inspiratory muscle training on pulmonary function, respiratory muscle strength and functional capacity in patients with atrial fibrillation. Prospective randomized controlled single-blind study. Cardiology department of a university hospital. A total of 38 patients with permanent atrial fibrillation were randomly allocated to either a treatment group (n = 19; age 66.2 years (8.8)) or a control group (n = 19; age 67.1 years (6.4)). The training group received inspiratory muscle training at 30% of maximal inspiratory pressure for 15 minutes twice a day, 7 days a week, for 12 weeks alongside the standard medical treatment. The control group received standard medical treatment only. Spirometry, maximal inspiratory and expiratory pressures and 6-minute walking distance was measured at the beginning and end of the study. There was a significant increase in maximal inspiratory pressure (27.94 cmH 2 O (8.90)), maximal expiratory pressure (24.53 cmH 2 O (10.34)), forced vital capacity (10.29% (8.18) predicted), forced expiratory volume in one second (13.88% (13.42) predicted), forced expiratory flow 25%-75% (14.82% (12.44) predicted), peak expiratory flow (19.82% (15.62) predicted) and 6-minute walking distance (55.53 m (14.13)) in the training group (p  0.05). Inspiratory muscle training can improve pulmonary function, respiratory muscle strength and functional capacity in patients with atrial fibrillation. © The Author(s) 2016.

  15. Muscle power failure in mobility-limited older adults: preserved single fiber function despite lower whole muscle size, quality and rate of neuromuscular activation.

    Science.gov (United States)

    Reid, Kieran F; Doros, Gheorghe; Clark, David J; Patten, Carolynn; Carabello, Robert J; Cloutier, Gregory J; Phillips, Edward M; Krivickas, Lisa S; Frontera, Walter R; Fielding, Roger A

    2012-06-01

    This study investigated the physiological and gender determinants of the age-related loss of muscle power in 31 healthy middle-aged adults (aged 40-55 years), 28 healthy older adults (70-85 years) and 34 mobility-limited older adults (70-85 years). We hypothesized that leg extensor muscle power would be significantly lower in mobility-limited elders relative to both healthy groups and sought to characterize the physiological mechanisms associated with the reduction of muscle power with aging. Computed tomography was utilized to assess mid-thigh body composition and calculate specific muscle power and strength. Surface electromyography was used to assess rate of neuromuscular activation and muscle biopsies were taken to evaluate single muscle fiber contractile properties. Peak muscle power, strength, muscle cross-sectional area, specific muscle power and rate of neuromuscular activation were significantly lower among mobility-limited elders compared to both healthy groups (P ≤ 0.05). Mobility-limited older participants had greater deposits of intermuscular adipose tissue (P mobility-limited elders relative to both healthy groups. Male gender was associated with greater decrements in peak and specific muscle power among mobility-limited participants. Impairments in the rate of neuromuscular activation and concomitant reductions in muscle quality are important physiological mechanisms contributing to muscle power deficits and mobility limitations. The dissociation between age-related changes at the whole muscle and single fiber level suggest that, even among older adults with overt mobility problems, contractile properties of surviving muscle fibers are preserved in an attempt to maintain overall muscle function.

  16. Functional electrical stimulation of intrinsic laryngeal muscles under varying loads in exercising horses.

    Directory of Open Access Journals (Sweden)

    Jon Cheetham

    Full Text Available Bilateral vocal fold paralysis (BVCP is a life threatening condition and appears to be a good candidate for therapy using functional electrical stimulation (FES. Developing a working FES system has been technically difficult due to the inaccessible location and small size of the sole arytenoid abductor, the posterior cricoarytenoid (PCA muscle. A naturally-occurring disease in horses shares many functional and etiological features with BVCP. In this study, the feasibility of FES for equine vocal fold paralysis was explored by testing arytenoid abduction evoked by electrical stimulation of the PCA muscle. Rheobase and chronaxie were determined for innervated PCA muscle. We then tested the hypothesis that direct muscle stimulation can maintain airway patency during strenuous exercise in horses with induced transient conduction block of the laryngeal motor nerve. Six adult horses were instrumented with a single bipolar intra-muscular electrode in the left PCA muscle. Rheobase and chronaxie were within the normal range for innervated muscle at 0.55±0.38 v and 0.38±0.19 ms respectively. Intramuscular stimulation of the PCA muscle significantly improved arytenoid abduction at all levels of exercise intensity and there was no significant difference between the level of abduction achieved with stimulation and control values under moderate loads. The equine larynx may provide a useful model for the study of bilateral fold paralysis.

  17. Electrostatic forces in muscle and cylindrical gel systems

    Energy Technology Data Exchange (ETDEWEB)

    Millman, B.M.; Nickel, B.G.

    1980-10-01

    Repulsive pressure has been measured as a function of lattice spacing in gels of tobacco mosaic virus (TMV) and in the filament lattice of vertebrate striated muscle. External pressures up to ten atm have been applied to these lattices by an osmotic stress method. Numerical solutions to the Poisson-Boltzmann equation in hexagonal lattices have been obtained and compared to the TMV and muscle data. The theoretical curves using values for kappa calculated from the ionic strength give a good fit to experimental data from TMV gels, and an approximate fit to that from the muscle lattice, provided that a charge radius for the muscle thick filaments of approx. 16 nm is assumed. Variations in ionic strength, sarcomere length and state of the muscle give results which agree qualitatively with the theory, though a good fit between experiment and theory in the muscle case will clearly require consideration of other types of forces. We conclude that Poisson-Boltzmann theory can provide a good first approximation to the long-range electrostatic forces operating in such biological gel systems.

  18. Functional deltoid muscle reconstruction following an extensive squamous cell carcinoma resection

    Directory of Open Access Journals (Sweden)

    Tang Weng Jun

    2016-07-01

    Full Text Available Squamous cell carcinoma frequently occurs in an individual with albinism. In this case, the growth of the squamous cell carcinoma was aggressive that it invaded the deltoid muscle. After an oncologic resection, there was a huge defect which required near total resection of the deltoid muscle. Loss of deltoid muscle will lead to the loss of abduction and anterior flexion at the shoulder. This could be debilitating in a person’s normal daily life and activities. Restoration of the shoulder abduction and flexion function with a pedicle bipolar latissimus dorsi flap transfer was chosen in this case due to the versatility and reliability of the flap.

  19. [Progress in isokinetic technology in testing and training for assessment of muscle function].

    Science.gov (United States)

    Huang, Ting-Ting; Fan, Li-Hua; Gao, Dong; Xia, Qing; Zhang, Min

    2013-02-01

    Isokinetic technology in testing and training is the most advanced practical technique in the evaluation of muscle function. This method is a continuous dynamic test in the full range of the joint motion which has strong pertinence at the aspect of assessing muscle strength, and is an objective and quantitative method for reflecting each point's muscle strength in the range of the joint motion. This article reviews the key concepts, brief history of development and influencing factors of isokinetic technology in testing and training, introduces the progress in the field of rehabilitation medicine and sport science, etc., and discusses the future exploration in forensic science.

  20. Evaluation of cardiorespiratory fitness and respiratory muscle function in the obese population.

    Science.gov (United States)

    Arena, Ross; Cahalin, Lawrence P

    2014-01-01

    Cardiorespiratory fitness (CRF) is one of the most important health metrics in apparently healthy individuals, those at increased risk for cardiovascular (CV) disease and virtually all patient populations. In addition to CRF, a host of other variables obtained from aerobic exercise testing provides clinically valuable information. Individuals classified as obese (i.e. a body mass index ≥30 kg/m(2)) have varying degrees of CV, pulmonary and skeletal muscle dysfunction that impact CRF and other key aerobic exercise testing variables. Moreover, there is now evidence indicating inspiratory and expiratory respiratory muscle function, even in the absence of interstitial lung disease, is potentially compromised as a result of obesity. When obesity-induced respiratory muscle dysfunction is present, it has the potential to contribute to the limitations in CRF. The current review will discuss aerobic exercise testing and the assessment of respiratory muscle function in the obese population. © 2014.

  1. Venous muscle pump function during pregnancy. Assessment by ambulatory strain-gauge plethysmography

    DEFF Research Database (Denmark)

    Struckmann, J R; Meiland, H; Bagi, P

    1990-01-01

    The venous muscle pump function was quantitatively assessed through pregnancy weeks 16, 30, 38 and 3 months (week 53) following delivery, in 24 pregnant women who completed a normal pregnancy. A statistically significant increase was found in the mean venous reflux (P less than 0.01), which was r...... primarily by mechanical obstruction, or hormonal influence other than that of estradiol, estriol or progesterone. 17% (4.7-37%) of the women with a normal pregnancy developed a pathological venous muscle pump function....... virtually disappeared post partum, corresponding to the muscle pump normalization. No statistical correlation was found between venous muscle pump values and changes in hormone concentrations of estradiol, estriol and progesterone. It is suggested that venous insufficiency development in pregnancy is caused...

  2. Enzymatically modified isoquercitrin supplementation intensifies plantaris muscle fiber hypertrophy in functionally overloaded mice

    OpenAIRE

    Kohara, Akiko; Machida, Masanao; Setoguchi, Yuko; Ito, Ryouichi; Sugitani, Masanori; Maruki-Uchida, Hiroko; Inagaki, Hiroyuki; Ito, Tatsuhiko; Omi, Naomi; Takemasa, Tohru

    2017-01-01

    Background Enzymatically modified isoquercitrin (EMIQ) is produced from rutin using enzymatic hydrolysis followed by treatment with glycosyltransferase in the presence of dextrin to add glucose residues. EMIQ is absorbed in the same way as quercetin, a powerful antioxidant reported to prevent disused muscle atrophy by targeting mitochondria and to have ergogenic effects. The present study investigated the effect of EMIQ on skeletal muscle hypertrophy induced by functional overload. Methods In...

  3. Musculoskeletal Geometry, Muscle Architecture and Functional Specialisations of the Mouse Hindlimb.

    Directory of Open Access Journals (Sweden)

    James P Charles

    Full Text Available Mice are one of the most commonly used laboratory animals, with an extensive array of disease models in existence, including for many neuromuscular diseases. The hindlimb is of particular interest due to several close muscle analogues/homologues to humans and other species. A detailed anatomical study describing the adult morphology is lacking, however. This study describes in detail the musculoskeletal geometry and skeletal muscle architecture of the mouse hindlimb and pelvis, determining the extent to which the muscles are adapted for their function, as inferred from their architecture. Using I2KI enhanced microCT scanning and digital segmentation, it was possible to identify 39 distinct muscles of the hindlimb and pelvis belonging to nine functional groups. The architecture of each of these muscles was determined through microdissections, revealing strong architectural specialisations between the functional groups. The hip extensors and hip adductors showed significantly stronger adaptations towards high contraction velocities and joint control relative to the distal functional groups, which exhibited larger physiological cross sectional areas and longer tendons, adaptations for high force output and elastic energy savings. These results suggest that a proximo-distal gradient in muscle architecture exists in the mouse hindlimb. Such a gradient has been purported to function in aiding locomotor stability and efficiency. The data presented here will be especially valuable to any research with a focus on the architecture or gross anatomy of the mouse hindlimb and pelvis musculature, but also of use to anyone interested in the functional significance of muscle design in relation to quadrupedal locomotion.

  4. Is the relationship between increased knee muscle strength and improved physical function following exercise dependent on baseline physical function status?

    Science.gov (United States)

    Hall, Michelle; Hinman, Rana S; van der Esch, Martin; van der Leeden, Marike; Kasza, Jessica; Wrigley, Tim V; Metcalf, Ben R; Dobson, Fiona; Bennell, Kim L

    2017-12-08

    Clinical guidelines recommend knee muscle strengthening exercises to improve physical function. However, the amount of knee muscle strength increase needed for clinically relevant improvements in physical function is unclear. Understanding how much increase in knee muscle strength is associated with improved physical function could assist clinicians in providing appropriate strength gain targets for their patients in order to optimise outcomes from exercise. The aim of this study was to investigate whether an increase in knee muscle strength is associated with improved self-reported physical function following exercise; and whether the relationship differs according to physical function status at baseline. Data from 100 participants with medial knee osteoarthritis enrolled in a 12-week randomised controlled trial comparing neuromuscular exercise to quadriceps strengthening exercise were pooled. Participants were categorised as having mild, moderate or severe physical dysfunction at baseline using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Associations between 12-week changes in physical function (dependent variable) and peak isometric knee extensor and flexor strength (independent variables) were evaluated with and without accounting for baseline physical function status and covariates using linear regression models. In covariate-adjusted models without accounting for baseline physical function, every 1-unit (Nm/kg) increase in knee extensor strength was associated with physical function improvement of 17 WOMAC units (95% confidence interval (CI) -29 to -5). When accounting for baseline severity of physical function, every 1-unit increase in knee extensor strength was associated with physical function improvement of 24 WOMAC units (95% CI -42 to -7) in participants with severe physical dysfunction. There were no associations between change in strength and change in physical function in participants with mild or moderate physical

  5. Effects of anabolic hormones on structural, metabolic and functional aspects of skeletal muscle

    Directory of Open Access Journals (Sweden)

    Flávio de Oliveira Pires

    2009-01-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2009v11n3p350   This study reviewed information regarding the effects of anabolic hormones on strength gain and muscle hypertrophy, emphasizing the physiological mechanisms that may increase muscle strength. Structural, metabolic and functional aspects were analyzed and special attention was paid to the dose-response relationship. The Pubmed database was searched and studies were selected according to relevance and date of publication (last 15 years. The administration of high testosterone doses (~600 mg/week potentiates the effects of strength training, increasing lean body mass, muscle fiber type IIA and IIB cross-sectional area, and the number of myonuclei. There is no evidence of conversion between MHC isoforms. The interaction between testosterone administration and strength training seems to modify some metabolic pathways, increasing protein synthesis, glycogen and ATP-CP muscle stores and improving fat mobilization. Changes in 17-estradiol concentration or in the ACTH-cortisol and insulin-glucagon ratios seem to be associated with these metabolic alterations. Regarding performance, testosterone administration may improve muscle strength by 5-20% depending on the dose used. On the other hand, the effects of growth hormone on the structural and functional aspects of skeletal muscle are not evident, with this hormone more affecting metabolic aspects. However, strictly controlled human studies are necessary to establish the extent of the effects of anabolic hormones on structural, metabolic and functional aspects.

  6. Muscle function and body composition profile in adolescents with restrictive anorexia nervosa: does resistance training help?

    Science.gov (United States)

    Fernández-del-Valle, Maria; Larumbe-Zabala, Eneko; Morande-Lavin, Gonzalo; Perez Ruiz, Margarita

    2016-01-01

    The aim of this study was to analyze the effects of short-term resistance training on the body composition profile and muscle function in a group of Anorexia Nervosa restricting type (AN-R) patients. The sample consisted of AN-R female adolescents (12.8 ± 0.6 years) allocated into the control and intervention groups (n = 18 each). Body composition and relative strength were assessed at baseline, after 8 weeks and 4 weeks following the intervention. Body mass index (BMI) increased throughout the study (p = 0.011). Significant skeletal muscle mass (SMM) gains were found in the intervention group (p = 0.045, d = 0.6) that correlated to the change in BMI (r = 0.51, p  0.60) with change in BMI in both the groups. Significant relative strength increases (p Anorexia Nervosa Restricting Type (AN-R) AN-R is a psychiatric disorder that has a major impact on muscle mass content and function. However, little or no attention has been paid to muscle recovery. High intensity resistance training is safe for AN-R after hospitalization and enhances the force generating capacity as well as muscle mass gains. Skeletal muscle mass content and muscular function improvements are partially maintained for a short period of time when the exercise program ceases.

  7. Effects of anabolic hormones on structural, metabolic and functional aspects of skeletal muscle

    Directory of Open Access Journals (Sweden)

    Flávio de Oliveira Pires

    2009-06-01

    Full Text Available This study reviewed information regarding the effects of anabolic hormones on strength gain and muscle hypertrophy, emphasizing the physiological mechanisms that may increase muscle strength. Structural, metabolic and functional aspects were analyzed and special attention was paid to the dose-response relationship. The Pubmed database was searched and studies were selected according to relevance and date of publication (last 15 years. The administration of high testosterone doses (~600 mg/week potentiates the effects of strength training, increasing lean body mass, muscle fiber type IIA and IIB cross-sectional area, and the number of myonuclei. There is no evidence of conversion between MHC isoforms. The interaction between testosterone administration and strength training seems to modify some metabolic pathways, increasing protein synthesis, glycogen and ATP-CP muscle stores and improving fat mobilization. Changes in 17-estradiol concentration or in the ACTH-cortisol and insulin-glucagon ratios seem to be associated with these metabolic alterations. Regarding performance, testosterone administration may improve muscle strength by 5-20% depending on the dose used. On the other hand, the effects of growth hormone on the structural and functional aspects of skeletal muscle are not evident, with this hormone more affecting metabolic aspects. However, strictly controlled human studies are necessary to establish the extent of the effects of anabolic hormones on structural, metabolic and functional aspects.

  8. [The pulmonary function and respiratory muscle power in multiple systemic atrophy and Parkinson's disease].

    Science.gov (United States)

    Wang, Yao; Zhang, Ying-dong; Gao, Li; Lu, Jie; Gu, Hao; Sun, Li-hua; Tan, Yan; Liu, Yun; Zhang, Jian-ping

    2013-07-01

    To investigate the characteristics of pulmonary function and respiratory muscle performance in patients with multiple system atrophy (MSA) and Parkinson's disease (PD). Pulmonary function and respiratory muscle strength were evaluated in 16 MSA patients and 20 PD patients. Another 17 age and sex-matched healthy volunteers were recruited as controls. Carbon monoxide diffusion capacity (DLCO) was significantly decreased in MSA group compared with PD group [(62.86 ± 15.66)% vs (76.67 ± 18.98)%, respectively, P respiratory dysfunction is involved in MSA and PD. The reduction of respiratory muscle strength is remarkable. The insufficiency of pulmonary diffusion function is more severe in MSA than in PD. More attention should be paid to the compromised respiratory function in neurodegenerative disorders.

  9. Skeletal Muscle Function during Exercise—Fine-Tuning of Diverse Subsystems by Nitric Oxide

    Directory of Open Access Journals (Sweden)

    Wilhelm Bloch

    2013-03-01

    Full Text Available Skeletal muscle is responsible for altered acute and chronic workload as induced by exercise. Skeletal muscle adaptations range from immediate change of contractility to structural adaptation to adjust the demanded performance capacities. These processes are regulated by mechanically and metabolically induced signaling pathways, which are more or less involved in all of these regulations. Nitric oxide is one of the central signaling molecules involved in functional and structural adaption in different cell types. It is mainly produced by nitric oxide synthases (NOS and by non-enzymatic pathways also in skeletal muscle. The relevance of a NOS-dependent NO signaling in skeletal muscle is underlined by the differential subcellular expression of NOS1, NOS2, and NOS3, and the alteration of NO production provoked by changes of workload. In skeletal muscle, a variety of highly relevant tasks to maintain skeletal muscle integrity and proper signaling mechanisms during adaptation processes towards mechanical and metabolic stimulations are taken over by NO signaling. The NO signaling can be mediated by cGMP-dependent and -independent signaling, such as S-nitrosylation-dependent modulation of effector molecules involved in contractile and metabolic adaptation to exercise. In this review, we describe the most recent findings of NO signaling in skeletal muscle with a special emphasis on exercise conditions. However, to gain a more detailed understanding of the complex role of NO signaling for functional adaptation of skeletal muscle (during exercise, additional sophisticated studies are needed to provide deeper insights into NO-mediated signaling and the role of non-enzymatic-derived NO in skeletal muscle physiology.

  10. Physical activity as intervention for age-related loss of muscle mass and function

    DEFF Research Database (Denmark)

    Eriksen, Christian Skou; Garde, Ellen; Reislev, Nina Linde

    2016-01-01

    INTRODUCTION: Physical and cognitive function decline with age, accelerating during the 6th decade. Loss of muscle power (force×velocity product) is a dominant physical determinant for loss of functional ability, especially if the lower extremities are affected. Muscle strength training is known...... and cognitive function, mental well-being, health-related quality of life and brain morphology. METHODS AND ANALYSIS: The study includes 450 home-dwelling men and women (62-70 years). Participants are randomly allocated to (1) 1 year of supervised, centre-based heavy resistance training, (2) home-based moderate...

  11. Sympathetic control of skeletal muscle function: possible co-operation between noradrenaline and neuropeptide Y in rabbit jaw muscles.

    Science.gov (United States)

    Grassi, C; Deriu, F; Roatta, S; Santarelli, R; Azzena, G B; Passatore, M

    1996-07-19

    Stimulation of the cervical sympathetic nerve at 10/s increases by 12.9 +/- 0.7% peak tension of maximal twitches in the directly stimulated jaw muscles and markedly depresses (41.6 +/- 1.3%) the tonic vibration reflex (TVR) elicited in the same muscles by vibration of the mandible. Both effects are not significantly influenced by administration of beta-adrenoceptor antagonists. When both alpha- and beta-adrenergic receptors are blocked, sympathetic stimulation induces a very small increase in twitch tension (3.8 +/- 0.7%), while no detectable change in the TVR is observed. Close arterial injection of alpha 1-adrenoceptor agonist phenylephrine mimics the effects induced by sympathetic stimulation on twitch tension and TVR, dose-dependently. The noradrenaline co-transmitter neuropeptide Y also produces a long-lasting, dose-dependent increase in the twitch tension which is unaffected by blockade of adrenergic receptors as well as of the neuromuscular junctions. Contribution of neuropeptide Y to the sympathetically-induced reduction of the stretch reflex is not clearly demonstrated. These data suggest that co-operation between noradrenaline and neuropeptide Y may be effective in determining sympathetic modulation of skeletal muscle function.

  12. Inefficient functional sympatholysis is an overlooked cause of malperfusion in contracting skeletal muscle

    DEFF Research Database (Denmark)

    Saltin, Bengt; Mortensen, Stefan P

    2012-01-01

    sympatholysis and muscle blood flow are impaired compared to young men, but regular physical activity can prevent these age related impairments. In young subjects, two weeks of leg immobilization causes a reduced ability for functional sympatholysis, whereas the trained leg maintained this function. Patients...

  13. Impaired exercise performance and skeletal muscle mitochondrial function in rats with secondary carnitine deficiency

    Directory of Open Access Journals (Sweden)

    Jamal BOUITBIR

    2016-08-01

    Full Text Available Purpose: The effects of carnitine depletion upon exercise performance and skeletal muscle mitochondrial function remain largely unexplored. We therefore investigated the effect of N-trimethyl-hydrazine-3-propionate (THP, a carnitine analogue inhibiting carnitine biosynthesis and renal carnitine reabsorption, on physical performance and skeletal muscle mitochondrial function in rats.Methods: Male Sprague Dawley rats were treated daily with water (control rats; n=12 or with 20 mg/100 g body weight THP (n=12 via oral gavage for 3 weeks. Following treatment, half of the animals of each group performed an exercise test until exhaustion.Results: Distance covered and exercise performance were lower in THP-treated compared to control rats. In the oxidative soleus muscle, carnitine depletion caused atrophy (-24% and impaired function of complex II and IV of the mitochondrial electron transport chain. The free radical leak (ROS production relative to oxygen consumption was increased and the cellular glutathione pool decreased. Moreover, mRNA expression of markers of mitochondrial biogenesis and mitochondrial DNA were decreased in THP-treated compared to control rats. In comparison, in the glycolytic gastrocnemius muscle, carnitine depletion was associated with impaired function of complex IV and increased free radical leak, whilst muscle weight and cellular glutathione pool were maintained. Markers of mitochondrial proliferation and mitochondrial DNA were unaffected.Conclusions: Carnitine deficiency is associated with impaired exercise capacity in rats treated with THP. THP-induced carnitine deficiency is associated with impaired function of the electron transport chain in oxidative and glycolytic muscle as well as with atrophy and decreased mitochondrial DNA in oxidative muscle.

  14. Effects of step length and step frequency on lower-limb muscle function in human gait.

    Science.gov (United States)

    Lim, Yoong Ping; Lin, Yi-Chung; Pandy, Marcus G

    2017-05-24

    The aim of this study was to quantify the effects of step length and step frequency on lower-limb muscle function in walking. Three-dimensional gait data were used in conjunction with musculoskeletal modeling techniques to evaluate muscle function over a range of walking speeds using prescribed combinations of step length and step frequency. The body was modeled as a 10-segment, 21-degree-of-freedom skeleton actuated by 54 muscle-tendon units. Lower-limb muscle forces were calculated using inverse dynamics and static optimization. We found that five muscles - GMAX, GMED, VAS, GAS, and SOL - dominated vertical support and forward progression independent of changes made to either step length or step frequency, and that, overall, changes in step length had a greater influence on lower-limb joint motion, net joint moments and muscle function than step frequency. Peak forces developed by the uniarticular hip and knee extensors, as well as the normalized fiber lengths at which these muscles developed their peak forces, correlated more closely with changes in step length than step frequency. Increasing step length resulted in larger contributions from the hip and knee extensors and smaller contributions from gravitational forces (limb posture) to vertical support. These results provide insight into why older people with weak hip and knee extensors walk more slowly by reducing step length rather than step frequency and also help to identify the key muscle groups that ought to be targeted in exercise programs designed to improve gait biomechanics in older adults. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Inspiratory muscle training improves respiratory muscle strength, functional capacity and quality of life in patients with chronic kidney disease: a systematic review

    Directory of Open Access Journals (Sweden)

    Ana Irene Carlos de Medeiros

    2017-04-01

    Registration: PROSPERO (CRD 42015029986. [de Medeiros AIC, Fuzari HKB, Rattesa C, Brandão DC, de Melo Marinho PÉ (2017 Inspiratory muscle training improves respiratory muscle strength, functional capacity and quality of life in patients with chronic kidney disease: a systematic review. Journal of Physiotherapy 63: 76–83

  16. Effect of flow-resistive inspiratory loading on pulmonary and respiratory muscle function in sub-elite swimmers.

    Science.gov (United States)

    Shei, Ren J; Lindley, Martin; Chatham, Ken; Mickleborough, Timothy D

    2016-04-01

    The aim of this study was to evaluate the effects of a 12-week swim training and inspiratory muscle training program on respiratory muscle and pulmonary function in competitively trained sub-elite swimmers. A double-blind, parallel-group experimental design was employed to compare the effects of swim training alone, swim training with sham-inspiratory muscle training, and swim training with true inspiratory muscle training. Twenty-four competitively trained sub-elite swimmers combined swim training with either flow-resistive inspiratory muscle training set at 80% sustained maximal inspiratory pressure with progressively increased work-rest ratios until task failure for 3 days/week (swim training with inspiratory muscle training, N.=8), or swim training with sham-inspiratory muscle training (N.=8), or acted as controls (swim training only, N.=8). Measures of pulmonary and respiratory muscle function were assessed at the beginning and end of the 12-week study period. At baseline, there were no significant differences (P>0.05) in respiratory muscle and pulmonary function between groups. Following the 12-week training period, the swim training with inspiratory muscle training group demonstrated improvements in maximal inspiratory pressure, sustained maximal inspiratory pressure, maximal inspiratory muscle power output, inspiratory muscle work capacity, inspiratory time of contraction, time to fatigue, maximal voluntary ventilation in 12 seconds, and forced inspiratory volume in 1-second (Prespiratory muscle function were observed in the swim training only or swim training with sham-inspiratory muscle training groups (P>0.05). Inspiratory muscle training in conjunction with swim training improves respiratory muscle function in sub-elite swimmers when compared to swim training only.

  17. Functional differences in the activity of the hamstring muscles with increasing running speed.

    Science.gov (United States)

    Higashihara, Ayako; Ono, Takashi; Kubota, Jun; Okuwaki, Toru; Fukubayashi, Toru

    2010-08-01

    In this study, we examined hamstring muscle activation at different running speeds to help better understand the functional characteristics of each hamstring muscle. Eight healthy male track and field athletes (20.1 +/- 1.1 years) performed treadmill running at 50%, 75%, 85%, and 95% of their maximum velocity. Lower extremity kinematics of the hip and knee joint were calculated. The surface electromyographic activities of the biceps femoris and semitendinosus muscles were also recorded. Increasing the running speed from 85% to 95% significantly increased the activation of the hamstring muscles during the late swing phase, while lower extremity kinematics did not change significantly. During the middle swing phase, the activity of the semitendinosus muscle was significantly greater than that of the biceps femoris muscle at 75%, 85%, and 95% of running speed. Statistically significant differences in peak activation time were observed between the biceps femoris and semitendinosus during 95%max running (P muscles were observed as running speed was increased, indicating that complex neuromuscular coordination patterns occurred during the running cycle at near maximum sprinting speeds.

  18. Function of the shoulder muscles during arm elevation: an assessment using positron emission tomography

    Science.gov (United States)

    Omi, Rei; Sano, Hirotaka; Ohnuma, Masahiro; Kishimoto, Koshi N; Watanuki, Shoichi; Tashiro, Manabu; Itoi, Eiji

    2010-01-01

    Although 2-deoxy-2-[18F]fluoro-D-glucose (FDG) positron emission tomography (PET) has been used for the assessment of skeletal muscle activities, its application to the shoulder muscles is only sparse. The purpose of this study was to investigate the activities of the shoulder muscles during arm elevation using PET. Six healthy volunteers performed an arm elevation exercise before and after FDG injection. The exercise consisted of 200 repetitions of arm elevation in the scapular plane with a 0.25-kg weight fixed to the wrist on both arms. PET examination was performed 50 min after FDG injection. For control data, PET scan was repeated for each subject on a separate day without any exercise. The volume of interest was established for each shoulder muscle. The subscapularis was divided into three portions (superior, middle, and inferior). The standardized uptake value (SUV) was calculated in each muscle to quantify its activity. The SUVs increased significantly after exercise in the deltoid, supraspinatus, and the superior portion of subscapularis. Among three divided portions of the subscapularis, the SUV of the superior one-third was significantly greater than the rest of the muscle after exercise. Our current study clearly indicated that there were two functionally different portions in the subscapularis muscle and the superior one-third played an important role during arm elevation in the scapular plane. PMID:20298439

  19. The functional significance of hamstrings composition: is it really a "fast" muscle group?

    Science.gov (United States)

    Evangelidis, Pavlos E; Massey, Garry J; Ferguson, Richard A; Wheeler, Patrick C; Pain, Matthew T G; Folland, Jonathan P

    2017-11-01

    Hamstrings muscle fiber composition may be predominantly fast-twitch and could explain the high incidence of hamstrings strain injuries. However, hamstrings muscle composition in vivo, and its influence on knee flexor muscle function, remains unknown. We investigated biceps femoris long head (BFlh) myosin heavy chain (MHC) composition from biopsy samples, and the association of hamstrings composition and hamstrings muscle volume (using MRI) with knee flexor maximal and explosive strength. Thirty-one young men performed maximal (concentric, eccentric, isometric) and explosive (isometric) contractions. BFlh exhibited a balanced MHC distribution [mean ± SD (min-max); 47.1 ± 9.1% (32.6-71.0%) MHC-I, 35.5 ± 8.5% (21.5-60.0%) MHC-IIA, 17.4 ± 9.1% (0.0-30.9%) MHC-IIX]. Muscle volume was correlated with knee flexor maximal strength at all velocities and contraction modes (r = 0.62-0.76, P hamstrings strain injury. Hamstrings muscle volume explained 38-58% of the inter-individual differences in knee flexor maximum strength at a range of velocities and contraction modes, while BFlh muscle composition was not associated with maximal or explosive strength. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Volumetric and functional evaluation of the gluteus maximus muscle after augmentation gluteoplasty using silicone implants.

    Science.gov (United States)

    Serra, Fernando; Aboudib, José Horácio; Neto, José Inácio Salles; Cossich, Victor Rodrigues Amaral; Rodrigues, Nádia Cristina Pinheiro; de Oliveira, Katia Fuhro; Marques, Ruy Garcia

    2015-03-01

    The gluteal muscles have been very important throughout the evolution of mankind for the adoption of the bipedal posture. Over the past 15 years, the intramuscular technique has become popular and has been improved, with enhanced results and reduced levels of postoperative complications. The insertion of gluteal implants within the musculature may be an intrinsic compression factor of these muscles. The objective of the present study was to evaluate the gluteus maximus function and its variation over a 12-month period after the insertion of the implant. This was a prospective, controlled, clinical study. All subjects were female patients, with anthropometric characteristics and body mass index within preset limits to establish similar groups. Isokinetic test gluteus computed tomographic scans and clinical nutritional assessment were conducted in four stages during the study period: preoperatively and 3, 6, and 12 months after surgery. The study group presented 6.14 percent muscle atrophy to the left and 6.43 percent muscle atrophy to the right after the procedure. Muscle strength presented differences in hip flexion and adduction tests. The gluteus maximus muscle presents atrophy secondarily to gluteal augmentation surgery with implants. Variations in gluteus maximus muscle strength should not be attributed primarily to the surgical procedure or to the implants; physiologic and multifactorial variations should also be considered. Strength and volume variations did not show a significant correlation. Gluteal augmentation with implants was effective in improving the waist-to-hip ratio and in changing the anthropometric pattern from android to gynoid. Therapeutic, II.

  1. Function of the shoulder muscles during arm elevation: an assessment using positron emission tomography.

    Science.gov (United States)

    Omi, Rei; Sano, Hirotaka; Ohnuma, Masahiro; Kishimoto, Koshi N; Watanuki, Shoichi; Tashiro, Manabu; Itoi, Eiji

    2010-05-01

    Although 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) has been used for the assessment of skeletal muscle activities, its application to the shoulder muscles is only sparse. The purpose of this study was to investigate the activities of the shoulder muscles during arm elevation using PET. Six healthy volunteers performed an arm elevation exercise before and after FDG injection. The exercise consisted of 200 repetitions of arm elevation in the scapular plane with a 0.25-kg weight fixed to the wrist on both arms. PET examination was performed 50 min after FDG injection. For control data, PET scan was repeated for each subject on a separate day without any exercise. The volume of interest was established for each shoulder muscle. The subscapularis was divided into three portions (superior, middle, and inferior). The standardized uptake value (SUV) was calculated in each muscle to quantify its activity. The SUVs increased significantly after exercise in the deltoid, supraspinatus, and the superior portion of subscapularis. Among three divided portions of the subscapularis, the SUV of the superior one-third was significantly greater than the rest of the muscle after exercise. Our current study clearly indicated that there were two functionally different portions in the subscapularis muscle and the superior one-third played an important role during arm elevation in the scapular plane.

  2. Diaphragm Muscle Adaptation to Sustained Hypoxia: Lessons from Animal Models with Relevance to High Altitude and Chronic Respiratory Diseases

    Directory of Open Access Journals (Sweden)

    Philip Lewis

    2016-12-01

    Full Text Available The diaphragm is the primary inspiratory pump muscle of breathing. Notwithstanding its critical role in pulmonary ventilation, the diaphragm like other striated muscles is malleable in response to physiological and pathophysiological stressors, with potential implications for the maintenance of respiratory homeostasis. This review considers hypoxic adaptation of the diaphragm muscle, with a focus on functional, structural, and metabolic remodeling relevant to conditions such as high altitude and chronic respiratory disease. On the basis of emerging data in animal models, we posit that hypoxia is a significant driver of respiratory muscle plasticity, with evidence suggestive of both compensatory and deleterious adaptations in conditions of sustained exposure to low oxygen. Cellular strategies driving diaphragm remodeling during exposure to sustained hypoxia appear to confer hypoxic tolerance at the expense of peak force-generating capacity, a key functional parameter that correlates with patient morbidity and mortality. Changes include, but are not limited to: redox-dependent activation of hypoxia-inducible factor (HIF and MAP kinases; time-dependent carbonylation of key metabolic and functional proteins; decreased mitochondrial respiration; activation of atrophic signaling and increased proteolysis; and, altered functional performance. Diaphragm muscle weakness may be a signature effect of sustained hypoxic exposure. We discuss the putative role of reactive oxygen species as mediators of both advantageous and disadvantageous adaptations of diaphragm muscle to sustained hypoxia, and the role of antioxidants in mitigating adverse effects of chronic hypoxic stress on respiratory muscle function.

  3. Comparative Statistical Mechanics of Muscle and Non-Muscle Contractile Systems: Stationary States of Near-Equilibrium Systems in A Linear Regime

    Directory of Open Access Journals (Sweden)

    Yves Lecarpentier

    2017-10-01

    Full Text Available A. Huxley’s equations were used to determine the mechanical properties of muscle myosin II (MII at the molecular level, as well as the probability of the occurrence of the different stages in the actin–myosin cycle. It was then possible to use the formalism of statistical mechanics with the grand canonical ensemble to calculate numerous thermodynamic parameters such as entropy, internal energy, affinity, thermodynamic flow, thermodynamic force, and entropy production rate. This allows us to compare the thermodynamic parameters of a non-muscle contractile system, such as the normal human placenta, with those of different striated skeletal muscles (soleus and extensor digitalis longus as well as the heart muscle and smooth muscles (trachea and uterus in the rat. In the human placental tissues, it was observed that the kinetics of the actin–myosin crossbridges were considerably slow compared with those of smooth and striated muscular systems. The entropy production rate was also particularly low in the human placental tissues, as compared with that observed in smooth and striated muscular systems. This is partly due to the low thermodynamic flow found in the human placental tissues. However, the unitary force of non-muscle myosin (NMII generated by each crossbridge cycle in the myofibroblasts of the human placental tissues was similar in magnitude to that of MII in the myocytes of both smooth and striated muscle cells. Statistical mechanics represents a powerful tool for studying the thermodynamics of all contractile muscle and non-muscle systems.

  4. Cost function tuning improves muscle force estimation computed by static optimization during walking.

    Science.gov (United States)

    Monaco, V; Coscia, M; Micera, S

    2011-01-01

    Muscle force estimation while a dynamic motor task is carried out still presents open questions. In particular, concerning locomotion, although the inverse dynamic based static optimization has been widely accepted as a suitable method to obtain reliable results, appropriate modifications of the object function may improve results. This paper was aimed at analyzing the sensitivity of estimated muscle forces when modifications of the objective function are adopted to better fit EMG signals of healthy subjects. A 7 links and 9 degrees of freedom biomechanical model accounting for 14 lower limb muscles, grouped in 9 equivalent actuators, was developed. Muscle forces were estimated by using the inverse dynamic based static optimization in which the performance criteria was the sum of muscle stresses raised to a certain n power. This exponent was gradually changed (from 2 to 100) and the agreement between force patterns and EMG signals was estimated by both the correlation coefficient and the Coactivation Index. Results suggested that force estimation can be improved by slightly modifying the cost function. In particular, with respect to adopted data, when the exponent belong to the interval between 2.75 and 4, estimated forces better captured general features of EMG signals. Concluding, a more reliable solution can be obtained by suitably tuning the cost function in order to fit EMG signals.

  5. Muscle contraction phenotypic analysis enabled by optogenetics reveals functional relationships of sarcomere components in Caenorhabditis elegans

    Science.gov (United States)

    Hwang, Hyundoo; Barnes, Dawn E.; Matsunaga, Yohei; Benian, Guy M.; Ono, Shoichiro; Lu, Hang

    2016-01-01

    The sarcomere, the fundamental unit of muscle contraction, is a highly-ordered complex of hundreds of proteins. Despite decades of genetics work, the functional relationships and the roles of those sarcomeric proteins in animal behaviors remain unclear. In this paper, we demonstrate that optogenetic activation of the motor neurons that induce muscle contraction can facilitate quantitative studies of muscle kinetics in C. elegans. To increase the throughput of the study, we trapped multiple worms in parallel in a microfluidic device and illuminated for photoactivation of channelrhodopsin-2 to induce contractions in body wall muscles. Using image processing, the change in body size was quantified over time. A total of five parameters including rate constants for contraction and relaxation were extracted from the optogenetic assay as descriptors of sarcomere functions. To potentially relate the genes encoding the sarcomeric proteins functionally, a hierarchical clustering analysis was conducted on the basis of those parameters. Because it assesses physiological output different from conventional assays, this method provides a complement to the phenotypic analysis of C. elegans muscle mutants currently performed in many labs; the clusters may provide new insights and drive new hypotheses for functional relationships among the many sarcomere components.

  6. Impact of backpack type on respiratory muscle strength and lung function in children.

    Science.gov (United States)

    Vieira, Ana Christina; Ribeiro, Fernando

    2015-01-01

    We examine the influence of backpack type on lung function and respiratory muscle strength in children. Thirty-seven children were assessed for lung function and inspiratory and expiratory muscle strength under four randomly determined conditions: unloaded erect standing and three conditions carrying 15% of the child's body weight. In these three conditions, children carried the weight on a backpack with bilateral shoulder straps carried over both shoulders, on a backpack with bilateral shoulder straps carried over one shoulder and on a backpack with a mono shoulder strap. Significantly lower forced vital capacity, forced expiratory volume in one second and maximal expiratory pressure were observed when children carried a backpack with a mono shoulder strap compared to the unloaded standing position. In conclusion, the restrictive effect and the decrease in expiratory muscle strength were more pronounced for the backpack with a mono shoulder strap, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack. Practitioner summary: There is little known about the effect of schoolbags on respiratory muscle function. We investigated the influence of backpack type on lung function and respiratory muscle strength. A backpack with a mono shoulder strap created a restrictive effect and a decrease in strength, suggesting that a double strap backpack is preferable to a mono shoulder strap backpack.

  7. Sodium channelopathies of skeletal muscle result from gain or loss of function

    Science.gov (United States)

    Jurkat-Rott, Karin; Holzherr, Boris; Fauler, Michael

    2010-01-01

    Five hereditary sodium channelopathies of skeletal muscle have been identified. Prominent symptoms are either myotonia or weakness caused by an increase or decrease of muscle fiber excitability. The voltage-gated sodium channel NaV1.4, initiator of the muscle action potential, is mutated in all five disorders. Pathogenetically, both loss and gain of function mutations have been described, the latter being the more frequent mechanism and involving not just the ion-conducting pore, but aberrant pores as well. The type of channel malfunction is decisive for therapy which consists either of exerting a direct effect on the sodium channel, i.e., by blocking the pore, or of restoring skeletal muscle membrane potential to reduce the fraction of inactivated channels. PMID:20237798

  8. Sodium channelopathies of skeletal muscle result from gain or loss of function.

    Science.gov (United States)

    Jurkat-Rott, Karin; Holzherr, Boris; Fauler, Michael; Lehmann-Horn, Frank

    2010-07-01

    Five hereditary sodium channelopathies of skeletal muscle have been identified. Prominent symptoms are either myotonia or weakness caused by an increase or decrease of muscle fiber excitability. The voltage-gated sodium channel NaV1.4, initiator of the muscle action potential, is mutated in all five disorders. Pathogenetically, both loss and gain of function mutations have been described, the latter being the more frequent mechanism and involving not just the ion-conducting pore, but aberrant pores as well. The type of channel malfunction is decisive for therapy which consists either of exerting a direct effect on the sodium channel, i.e., by blocking the pore, or of restoring skeletal muscle membrane potential to reduce the fraction of inactivated channels.

  9. Fast-twitch glycolytic skeletal muscle is predisposed to age-induced impairments in mitochondrial function

    DEFF Research Database (Denmark)

    Jacobs, Robert A; Díaz, Víctor; Soldini, Lavinia

    2013-01-01

    -resolution respirometry and mitochondrial protein expression in soleus, quadricep, and lateral gastrocnemius skeletal muscles, which represent type 1 slow-twitch oxidative muscle (soleus) and type 2 fast-twitch glycolytic muscle (quadricep and gastrocnemius), respectively, in young (10-12 weeks) and mature (74-76 weeks......) mice. Electron transport through mitochondrial complexes I and III increases with age in quadricep and gastrocnemius, which is not observed in soleus. Mitochondrial coupling efficiency during respiration through complex I also deteriorates with age in gastrocnemius and shows a tendency (p = .085......) to worsen in quadricep. These data demonstrate actual alterations in electron transport function that occurs with age and are dependent on skeletal muscle type....

  10. Resistance training improves muscle strength and functional capacity in multiple sclerosis

    DEFF Research Database (Denmark)

    Dalgas, U; Stenager, E; Jakobsen, J

    2009-01-01

    OBJECTIVE: To test the hypothesis that lower extremity progressive resistance training (PRT) can improve muscle strength and functional capacity in patients with multiple sclerosis (MS) and to evaluate whether the improvements are maintained after the trial. METHODS: The present study was a 2-arm...... and was afterward encouraged to continue training. After the trial, the control group completed the PRT intervention. Both groups were tested before and after 12 weeks of the trial and at 24 weeks (follow-up), where isometric muscle strength of the knee extensors (KE MVC) and functional capacity (FS; combined score...... strength and functional capacity in patients with multiple sclerosis, the effects persisting after 12 weeks of self-guided physical activity. Level of evidence: The present study provides level III evidence supporting the hypothesis that lower extremity progressive resistance training can improve muscle...

  11. Short-term strength training improves muscle quality and functional capacity of elderly women.

    Science.gov (United States)

    Pinto, Ronei Silveira; Correa, Cleiton Silva; Radaelli, Regis; Cadore, Eduardo Lusa; Brown, Lee E; Bottaro, Martim

    2014-02-01

    To assess effects of a short-term strength training (ST) program on muscle quality (MQ) and functional capacity, 36 sedentary elderly women (age = 66.0 ± 8 year, height = 159.1 ± 9.2 cm, body mass = 68.3 ± 12.1 kg, body fat = 37.0 ± 4.2 %) were randomly divided into an experimental group (EG; n = 19) or a control group (CG; n = 17). The EG performed two to three sets of 12-15 repeats of leg press, knee extension, and knee flexion exercises, 2 days/week for 6 weeks. Before and after training, lower body one repetition maximum (1RM), functional performance tests, quadriceps femoris muscle thickness (MT), and muscle quality (MQ) (1RM and quadriceps MT quotient) were assessed. After training, only the EG showed significant improvements in 1RM (p elderly women, which resulted in beneficial changes in functional capacity.

  12. 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

  13. Tumor growth increases neuroinflammation, fatigue and depressive-like behavior prior to alterations in muscle function.

    Science.gov (United States)

    Norden, Diana M; Bicer, Sabahattin; Clark, Yvonne; Jing, Runfeng; Henry, Christopher J; Wold, Loren E; Reiser, Peter J; Godbout, Jonathan P; McCarthy, Donna O

    2015-01-01

    Cancer patients frequently suffer from fatigue, a complex syndrome associated with loss of muscle mass, weakness, and depressed mood. Cancer-related fatigue (CRF) can be present at the time of diagnosis, during treatment, and persists for years after treatment. CRF negatively influences quality of life, limits functional independence, and is associated with decreased survival in patients with incurable disease. Currently there are no effective treatments to reduce CRF. The aim of this study was to use a mouse model of tumor growth and discriminate between two main components of fatigue: loss of muscle mass/function and altered mood/motivation. Here we show that tumor growth increased fatigue- and depressive-like behaviors, and reduced body and muscle mass. Decreased voluntary wheel running activity (VWRA) and increased depressive-like behavior in the forced swim and sucrose preference tests were evident in tumor-bearing mice within the first two weeks of tumor growth and preceded the loss of body and muscle mass. At three weeks, tumor-bearing mice had reduced grip strength but this was not associated with altered expression of myosin isoforms or impaired contractile properties of muscles. These increases in fatigue and depressive-like behaviors were paralleled by increased expression of IL-1β mRNA in the cortex and hippocampus. Minocycline administration reduced tumor-induced expression of IL-1β in the brain, reduced depressive-like behavior, and improved grip strength without altering muscle mass. Taken together, these results indicate that neuroinflammation and depressed mood, rather than muscle wasting, contribute to decreased voluntary activity and precede major changes in muscle contractile properties with tumor growth. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. AQP4-dependent water transport plays a functional role in exercise-induced skeletal muscle adaptations.

    Directory of Open Access Journals (Sweden)

    Davide Basco

    Full Text Available In this study we assess the functional role of Aquaporin-4 (AQP4 in the skeletal muscle by analyzing whether physical activity modulates AQP4 expression and whether the absence of AQP4 has an effect on osmotic behavior, muscle contractile properties, and physical activity. To this purpose, rats and mice were trained on the treadmill for 10 (D10 and 30 (D30 days and tested with exercise to exhaustion, and muscles were used for immunoblotting, RT-PCR, and fiber-type distribution analysis. Taking advantage of the AQP4 KO murine model, functional analysis of AQP4 was performed on dissected muscle fibers and sarcolemma vesicles. Moreover, WT and AQP4 KO mice were subjected to both voluntary and forced activity. Rat fast-twitch muscles showed a twofold increase in AQP4 protein in D10 and D30 rats compared to sedentary rats. Such increase positively correlated with the animal performance, since highest level of AQP4 protein was found in high runner rats. Interestingly, no shift in muscle fiber composition nor an increase in AQP4-positive fibers was found. Furthermore, no changes in AQP4 mRNA after exercise were detected, suggesting that post-translational events are likely to be responsible for AQP4 modulation. Experiments performed on AQP4 KO mice revealed a strong impairment in osmotic responses as well as in forced and voluntary activities compared to WT mice, even though force development amplitude and contractile properties were unvaried. Our findings definitively demonstrate the physiological role of AQP4 in supporting muscle contractile activity and metabolic changes that occur in fast-twitch skeletal muscle during prolonged exercise.

  15. The Effects of Low Levels of Dystrophin on Mouse Muscle Function and Pathology

    Science.gov (United States)

    van Putten, Maaike; Hulsker, Margriet; Nadarajah, Vishna Devi; van Heiningen, Sandra H.; van Huizen, Ella; van Iterson, Maarten; Admiraal, Peter; Messemaker, Tobias; den Dunnen, Johan T.; 't Hoen, Peter A. C.; Aartsma-Rus, Annemieke

    2012-01-01

    Duchenne muscular dystrophy (DMD) is a severe progressive muscular disorder caused by reading frame disrupting mutations in the DMD gene, preventing the synthesis of functional dystrophin. As dystrophin provides muscle fiber stability during contractions, dystrophin negative fibers are prone to exercise-induced damage. Upon exhaustion of the regenerative capacity, fibers will be replaced by fibrotic and fat tissue resulting in a progressive loss of function eventually leading to death in the early thirties. With several promising approaches for the treatment of DMD aiming at dystrophin restoration in clinical trials, there is an increasing need to determine more precisely which dystrophin levels are sufficient to restore muscle fiber integrity, protect against muscle damage and improve muscle function. To address this we generated a new mouse model (mdx-Xist Δhs) with varying, low dystrophin levels (3–47%, mean 22.7%, stdev 12.1, n = 24) due to skewed X-inactivation. Longitudinal sections revealed that within individual fibers, some nuclei did and some did not express dystrophin, resulting in a random, mosaic pattern of dystrophin expression within fibers. Mdx-Xist Δhs, mdx and wild type females underwent a 12 week functional test regime consisting of different tests to assess muscle function at base line, or after chronic treadmill running exercise. Overall, mdx-Xist Δhs mice with 3–14% dystrophin outperformed mdx mice in the functional tests. Improved histopathology was observed in mice with 15–29% dystrophin and these levels also resulted in normalized expression of pro-inflammatory biomarker genes, while for other parameters >30% of dystrophin was needed. Chronic exercise clearly worsened pathology, which needed dystrophin levels >20% for protection. Based on these findings, we conclude that while even dystrophin levels below 15% can improve pathology and performance, levels of >20% are needed to fully protect muscle fibers from exercise

  16. Age-related functional changes and susceptibility to eccentric contraction-induced damage in skeletal muscle cell

    Directory of Open Access Journals (Sweden)

    Seung-Jun Choi

    2016-09-01

    Full Text Available Depending upon external loading conditions, skeletal muscles can either shorten, lengthen, or remain at a fixed length as they produce force. Fixed-end or isometric contractions stabilize joints and allow muscles to act as active struts during locomotion. Active muscles dissipate energy when they are lengthened by an external force that exceeds their current force producing capacity. These unaccustomed eccentric activities often lead to muscle weakness, soreness, and inflammation. During aging, the ability to produce force under these conditions is reduced and appears to be due to not only reductions in muscle mass but also to alterations in the basic mechanisms of contraction. These alterations include impairments in the excitation–contraction process, and the action of the cross-bridges. Also, it is well known that age-related skeletal muscle atrophy is characterized by a preferential atrophy of fast fibers, and increased susceptibility to fast muscle fiber when aged muscles are exposed to eccentric contraction followed by the impaired recovery process has been reported. Taken together, the selective loss of fast muscle fiber in aged muscle could be affected by eccentric-induced muscle damage, which has significant implication to identify the etiology of the age-related functional changes. Therefore, in this review the alteration of age-related muscle function and its impact to/of eccentric induced muscle damage and recovery will be addressed in detail.

  17. Age-related functional changes and susceptibility to eccentric contraction-induced damage in skeletal muscle cell.

    Science.gov (United States)

    Choi, Seung-Jun

    2016-09-01

    Depending upon external loading conditions, skeletal muscles can either shorten, lengthen, or remain at a fixed length as they produce force. Fixed-end or isometric contractions stabilize joints and allow muscles to act as active struts during locomotion. Active muscles dissipate energy when they are lengthened by an external force that exceeds their current force producing capacity. These unaccustomed eccentric activities often lead to muscle weakness, soreness, and inflammation. During aging, the ability to produce force under these conditions is reduced and appears to be due to not only reductions in muscle mass but also to alterations in the basic mechanisms of contraction. These alterations include impairments in the excitation-contraction process, and the action of the cross-bridges. Also, it is well known that age-related skeletal muscle atrophy is characterized by a preferential atrophy of fast fibers, and increased susceptibility to fast muscle fiber when aged muscles are exposed to eccentric contraction followed by the impaired recovery process has been reported. Taken together, the selective loss of fast muscle fiber in aged muscle could be affected by eccentric-induced muscle damage, which has significant implication to identify the etiology of the age-related functional changes. Therefore, in this review the alteration of age-related muscle function and its impact to/of eccentric induced muscle damage and recovery will be addressed in detail.

  18. Muscle function is associated with future patient-reported outcomes in young adults with ACL injury

    DEFF Research Database (Denmark)

    Flosadottir, Vala; Roos, Ewa M; Ageberg, Eva

    2016-01-01

    extremity muscle function and PROs after ACL injury. METHODS: Fifty-four participants (15 women, mean 30 years) with ACL injury or reconstruction, from the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) trial (ISRCTN84752559), were assessed with hop performance, muscle power...... and postural orientation 3 years (SD 0.85) after ACL injury. PROs at 3 and 5 years after injury included Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales Function in sport and recreation (KOOS Sport/rec) and Knee-related Quality of life (KOOS QoL), KOOS item Q3 (KOOS Q3), Tegner Activity Scale...

  19. Premature loss of muscle mass and function in type 2 diabetes.

    Science.gov (United States)

    Guerrero, N; Bunout, D; Hirsch, S; Barrera, G; Leiva, L; Henríquez, S; De la Maza, M P

    2016-07-01

    Muscle mass and function are among the most relevant factors that contribute to an optimal quality of life, and are strong predictors of mortality in the elderly. Loss of lean tissues and deterioration of muscle function have been described as one of the many complications of type 2 diabetes mellitus (DM2), but most studies do not isolate age as an intervening factor. To study whether adult DM2 patients up to 60years of age have decreased muscle mass and function compared with healthy non-diabetic (ND) subjects of similar age. Appendicular fat-free mass (ApFFM) by dual X-ray absorptiometry (DEXA), handgrip strength (HS), quadriceps strength (QS), 12 min walking capacity (12MW) and the Timed Up and Go test (TUG) were measured in 100 DM2 patients and 39 ND controls. Muscle quality, or the ratio between lean mass and muscle strength of upper and lower limbs, and the functional limitations associated with pain and stiffness assessed according to the Western Ontario and McMaster Universities Arthrosis Index (WOMAC) were also recorded. Specific tests were performed to rule out microvascular diabetic complications (retinal and peripheral nerves), metabolic control, kidney function and vitamin D status and examine their association with ApFFM and function. ApFFM was significantly higher among DM2 female patients and lower among diabetic men. However opposite results were obtained when individual values were corrected for body mass index (BMI), specifically among women, who were more likely to be obese. As for muscle strength and global functionality tests, significantly better performances in TUG, 12MW, QS and HS were observed among ND subjects of both sexes. These differences prevailed even after excluding diabetic patients with microvascular complications as well as those with more than 10years of diabetes. Muscle quality was also significantly better among ND women. Higher scores of pain and stiffness in the WOMAC scale correlated with 12MW and TUG in both groups but

  20. Isolation and individual electrical stimulation of single smooth-muscle cells from the urinary bladder of the pig

    NARCIS (Netherlands)

    J.J. Glerum (Jacobus); R. van Mastrigt (Ron); J.C. Romijn (Johannes); D.J. Griffiths (Derek)

    1987-01-01

    textabstractIn contrast to striated muscle, measurements on strips of smooth muscle cannot be uniquely interpreted in terms of an array of contractile units. Therefore scaling down to the single-cell level is necessary to gain detailed understanding of the contractile process in this type of muscle.

  1. Initial intramuscular perfusion pressure predicts early skeletal muscle function following isolated tibial fractures

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    Haas Norbert P

    2008-04-01

    Full Text Available Abstract Background The severity of associated soft tissue trauma in complex injuries of the extremities guides fracture treatment and decisively determines patient's prognosis. Trauma-induced microvascular dysfunction and increased tissue pressure is known to trigger secondary soft tissue damage and seems to adversely affect skeletal muscle function. Methods 20 patients with isolated tibial fractures were included. Blood pressure and compartment pressure (anterior and deep posterior compartment were measured continuously up to 24 hours. Corresponding perfusion pressure was calculated. After 4 and 12 weeks isokinetic muscle peak torque and mean power of the ankle joint in dorsal and plantar flexion were measured using a Biodex dynamometer. Results A significant inverse correlation between the anterior perfusion pressure at 24 hours and deficit in dorsiflexion at 4 weeks was found for both, the peak torque (R = -0.83; p Conclusion The functional relationship between the decrease in intramuscular perfusion pressures and muscle performance in the early rehabilitation period indicate a causative and prognostic role of early posttraumatic microcirculatory derangements and skeletal muscle function. Therapeutic concepts aimed at effective muscle recovery, early rehabilitation, and decreased secondary tissue damage, should consider the maintenance of an adequate intramuscular perfusion pressure.

  2. Lung Function, Respiratory Muscle Strength, and Thoracoabdominal Mobility in Women With Fibromyalgia Syndrome.

    Science.gov (United States)

    Forti, Meire; Zamunér, Antonio R; Andrade, Carolina P; Silva, Ester

    2016-10-01

    Fibromyalgia syndrome (FMS) is associated with a variety of symptoms, such as fatigue and dyspnea, which may be related to changes in the respiratory system. The objective of this work was to evaluate pulmonary function, respiratory muscle strength, and thoracoabdominal mobility in women with FMS and its association with clinical manifestations. The study included 23 women with FMS and 23 healthy women (control group). Pulmonary function, respiratory muscle strength, and thoracoabdominal mobility were assessed in all participants. Clinical manifestations such as number of active tender points, pain, fatigue, well-being, and general pressure pain threshold and pressure pain threshold in regions involved in respiratory function were also assessed. For data analysis, the Mann-Whitney test and Spearman correlation coefficient were used. The FMS group showed lower values of maximum voluntary ventilation (P = .030), maximal inspiratory pressure (P = .003), and cirtometry at the axillary and xiphoid levels (P respiratory muscle endurance, inspiratory muscle strength, and thoracic mobility than healthy subjects. In addition, inspiratory muscle strength was associated with the number of active tender points, fatigue, and axillary mobility. Copyright © 2016 by Daedalus Enterprises.

  3. PDE5 inhibition alleviates functional muscle ischemia in boys with Duchenne muscular dystrophy

    Science.gov (United States)

    Nelson, Michael D.; Rader, Florian; Tang, Xiu; Tavyev, Jane; Nelson, Stanley F.; Miceli, M. Carrie; Elashoff, Robert M.; Sweeney, H. Lee

    2014-01-01

    Objective: To determine whether phosphodiesterase type 5 (PDE5) inhibition can alleviate exercise-induced skeletal muscle ischemia in boys with Duchenne muscular dystrophy (DMD). Methods: In 10 boys with DMD and 10 healthy age-matched male controls, we assessed exercise-induced attenuation of reflex sympathetic vasoconstriction, i.e., functional sympatholysis, a protective mechanism that matches oxygen delivery to metabolic demand. Reflex vasoconstriction was induced by simulated orthostatic stress, measured as the decrease in forearm muscle oxygenation with near-infrared spectroscopy, and performed when the forearm muscles were rested or lightly exercised with rhythmic handgrip exercise. Then, the patients underwent an open-label, dose-escalation, crossover trial with single oral doses of tadalafil or sildenafil. Results: The major new findings are 2-fold: first, sympatholysis is impaired in boys with DMD—producing functional muscle ischemia—despite contemporary background therapy with corticosteroids alone or in combination with cardioprotective medication. Second, PDE5 inhibition with standard clinical doses of either tadalafil or sildenafil alleviates this ischemia in a dose-dependent manner. Furthermore, PDE5 inhibition also normalizes the exercise-induced increase in skeletal muscle blood flow (measured by Doppler ultrasound), which is markedly blunted in boys with DMD. Conclusions: These data provide in-human proof of concept for PDE5 inhibition as a putative new therapeutic strategy for DMD. Classification of evidence: This study provides Class IV evidence that in patients with DMD, PDE5 inhibition restores functional sympatholysis. PMID:24808022

  4. Investigations of the Effects of Altered Vestibular System Function on Hindlimb Anti-Gravity Muscles

    Science.gov (United States)

    Lowery, Mary Sue

    1998-01-01

    Exposure to different gravitational environments, both the microgravity of spaceflight and the hypergravity of centrifugation, result in altered vestibulo-spinal function which can be reversed by reacclimation to earth gravity (2). Control of orientation, posture, and locomotion are functions of the vestibular system which are altered by changes in gravitational environment. Not only is the vestibular system involved with coordination and proprioception, but the gravity sensing portion of the vestibular system also plays a major role in maintaining muscle tone through projections to spinal cord motoneurons that control anti-gravity muscles. I have been involved with investigations of several aspects of the link between vestibular inputs and muscle morphology and function during my work with Dr. Nancy Daunton this summer and the previous summer. We have prepared a manuscript for submission (4) to Aviation, Space, and Environmental Medicine based on work that I performed last summer in Dr. Daunton's lab. Techniques developed for that project will be utilized in subsequent experiments begun in the summer of 1998. I have been involved with the development of a pilot project to test the effects of vestibular galvanic stimulation (VGS) on anti-gravity muscles and in another project testing the effects of the ototoxic drug streptomycin on the otolith-spinal reflex and anti-gravity muscle morphology.

  5. Poloxamer [corrected] 188 has a deleterious effect on dystrophic skeletal muscle function.

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    Rebecca L Terry

    Full Text Available Duchenne muscular dystrophy (DMD is an X-linked, fatal muscle wasting disease for which there is currently no cure and limited palliative treatments. Poloxomer 188 (P188 is a tri-block copolymer that has been proposed as a potential treatment for cardiomyopathy in DMD patients. Despite the reported beneficial effects of P188 on dystrophic cardiac muscle function, the effects of P188 on dystrophic skeletal muscle function are relatively unknown. Mdx mice were injected intraperitoneally with 460 mg/kg or 30 mg/kg P188 dissolved in saline, or saline alone (control. The effect of single-dose and 2-week daily treatment was assessed using a muscle function test on the Tibialis Anterior (TA muscle in situ in anaesthetised mice. The test comprises a warm up, measurement of the force-frequency relationship and a series of eccentric contractions with a 10% stretch that have previously been shown to cause a drop in maximum force in mdx mice. After 2 weeks of P188 treatment at either 30 or 460 mg/kg/day the drop in maximum force produced following eccentric contractions was significantly greater than that seen in saline treated control mice (P = 0.0001. Two week P188 treatment at either dose did not significantly change the force-frequency relationship or maximum isometric specific force produced by the TA muscle. In conclusion P188 treatment increases susceptibility to contraction-induced injury following eccentric contractions in dystrophic skeletal muscle and hence its suitability as a potential therapeutic for DMD should be reconsidered.

  6. Target genes of myostatin loss-of-function in muscles of late bovine fetuses

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    Hocquette Jean-François

    2007-03-01

    Full Text Available Abstract Background Myostatin, a muscle-specific member of the Transforming Growth Factor beta family, negatively regulates muscle development. Double-muscled (DM cattle have a loss-of-function mutation in their myostatin gene responsible for the hypermuscular phenotype. Thus, these animals are a good model for understanding the mechanisms underpinning muscular hypertrophy. In order to identify individual genes or networks that may be myostatin targets, we looked for genes that were differentially expressed between DM and normal (NM animals (n = 3 per group in the semitendinosus muscle (hypertrophied in DM animals at 260 days of fetal development (when the biochemical differentiation of muscle is intensive. A heterologous microarray (human and murine oligonucleotide sequences of around 6,000 genes expressed in muscle was used. Results Many genes were found to be differentially expressed according to genetic type (some with a more than 5-fold change, and according to the presence of one or two functional myostatin allele(s. They belonged to various functional categories. The genes down-regulated in DM fetuses were mainly those encoding extracellular matrix proteins, slow contractile proteins and ribosomal proteins. The genes up-regulated in DM fetuses were mainly involved in the regulation of transcription, cell cycle/apoptosis, translation or DNA metabolism. These data highlight features indicating that DM muscle is shifted towards a more glycolytic metabolism, and has an altered extracellular matrix composition (e.g. down-regulation of COL1A1 and COL1A2, and up-regulation of COL4A2 and decreased adipocyte differentiation (down-regulation of C1QTNF3. The altered gene expression in the three major muscle compartments (fibers, connective tissue and intramuscular adipose tissue is consistent with the well-known characteristics of DM cattle. In addition, novel potential targets of the myostatin gene were identified (MB, PLN, troponins, ZFHX1B

  7. Characterization of the equine skeletal muscle transcriptome identifies novel functional responses to exercise training.

    LENUS (Irish Health Repository)

    McGivney, Beatrice A

    2010-01-01

    BACKGROUND: Digital gene expression profiling was used to characterize the assembly of genes expressed in equine skeletal muscle and to identify the subset of genes that were differentially expressed following a ten-month period of exercise training. The study cohort comprised seven Thoroughbred racehorses from a single training yard. Skeletal muscle biopsies were collected at rest from the gluteus medius at two time points: T(1) - untrained, (9 +\\/- 0.5 months old) and T(2) - trained (20 +\\/- 0.7 months old). RESULTS: The most abundant mRNA transcripts in the muscle transcriptome were those involved in muscle contraction, aerobic respiration and mitochondrial function. A previously unreported over-representation of genes related to RNA processing, the stress response and proteolysis was observed. Following training 92 tags were differentially expressed of which 74 were annotated. Sixteen genes showed increased expression, including the mitochondrial genes ACADVL, MRPS21 and SLC25A29 encoded by the nuclear genome. Among the 58 genes with decreased expression, MSTN, a negative regulator of muscle growth, had the greatest decrease.Functional analysis of all expressed genes using FatiScan revealed an asymmetric distribution of 482 Gene Ontology (GO) groups and 18 KEGG pathways. Functional groups displaying highly significant (P < 0.0001) increased expression included mitochondrion, oxidative phosphorylation and fatty acid metabolism while functional groups with decreased expression were mainly associated with structural genes and included the sarcoplasm, laminin complex and cytoskeleton. CONCLUSION: Exercise training in Thoroughbred racehorses results in coordinate changes in the gene expression of functional groups of genes related to metabolism, oxidative phosphorylation and muscle structure.

  8. Regulation and functions of the lms homeobox gene during development of embryonic lateral transverse muscles and direct flight muscles in Drosophila.

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    Dominik Müller

    Full Text Available BACKGROUND: Patterning and differentiation of developing musculatures require elaborate networks of transcriptional regulation. In Drosophila, significant progress has been made into identifying the regulators of muscle development and defining their interactive networks. One major family of transcription factors involved in these processes consists of homeodomain proteins. In flies, several members of this family serve as muscle identity genes to specify the fates of individual muscles, or groups thereof, during embryonic and/or adult muscle development. Herein, we report on the expression and function of a new Drosophila homeobox gene during both embryonic and adult muscle development. METHODOLOGY/PRINCIPAL FINDINGS: The newly described homeobox gene, termed lateral muscles scarcer (lms, which has yet uncharacterized orthologs in other invertebrates and primitive chordates but not in vertebrates, is expressed exclusively in subsets of developing muscle tissues. In embryos, lms is expressed specifically in the four lateral transverse (LT muscles and their founder cells in each hemisegment, whereas in larval wing imaginal discs, it is expressed in myoblasts that develop into direct flight muscles (DFMs, which are important for proper wing positioning. We have analyzed the regulatory inputs of various other muscle identity genes with overlapping or complementary expression patterns towards the cell type specific regulation of lms expression. Further we demonstrate that lms null mutants exhibit reduced numbers of embryonic LT muscles, and null mutant adults feature held-out-wing phenotypes. We provide a detailed description of the pattern and morphology of the direct flight muscles in the wild type and lms mutant flies by using the recently-developed ultramicroscopy and show that, in the mutants, all DFMs are present and present normal morphologies. CONCLUSIONS/SIGNIFICANCE: We have identified the homeobox gene lms as a new muscle identity gene

  9. A Comparison of Muscle Function, Mass, and Quality in Liver Transplant Candidates: Results From the Functional Assessment in Liver Transplantation Study.

    Science.gov (United States)

    Wang, Connie W; Feng, Sandy; Covinsky, Kenneth E; Hayssen, Hilary; Zhou, Li-Qin; Yeh, Benjamin M; Lai, Jennifer C

    2016-08-01

    Sarcopenia and functional impairment are common and lethal extrahepatic manifestations of cirrhosis. We aimed to determine the association between computed tomography (CT)-based measures of muscle mass and quality (sarcopenia) and performance-based measures of muscle function. Adults listed for liver transplant underwent testing of muscle function (grip strength, Short Physical Performance Battery [SPPB]) within 3 months of abdominal CT. Muscle mass (cm/m) = total cross-sectional area of psoas, paraspinal, and abdominal wall muscles at L3 on CT, normalized for height. Muscle quality = mean Hounsfield units for total skeletal muscle area at L3. Among 292 candidates, median grip strength was 31 kg, SPPB score was 11, muscle mass was 49 cm/m, and muscle quality was 35 Hounsfield units. Grip strength weakly correlated with muscle mass (ρ = 0.26, P strength (hazard ratio [HR], 0.74; 95% confidence interval [95% CI], 0.59-0.92; P = 0.008), SPPB (HR, 0.89; 95% CI, 0.82-0.97; P = 0.01), and muscle quality (HR, 0.77; 95% CI, 0.63-0.95; P = 0.02) were associated with waitlist mortality, but muscle mass was not (HR, 0.91; 95% CI, 0.75-1.11; P = 0.35). Performance-based tests of muscle function are only modestly associated with CT-based muscle measures. Given that they predict waitlist mortality and can be conducted quickly and economically, tests of muscle function may have greater clinical utility than CT-based measures of sarcopenia.

  10. Effects of a multichannel dynamic functional electrical stimulation system on hemiplegic gait and muscle forces.

    Science.gov (United States)

    Qian, Jing-Guang; Rong, Ke; Qian, Zhenyun; Wen, Chen; Zhang, Songning

    2015-11-01

    [Purpose] The purpose of the study was to design and implement a multichannel dynamic functional electrical stimulation system and investigate acute effects of functional electrical stimulation of the tibialis anterior and rectus femoris on ankle and knee sagittal-plane kinematics and related muscle forces of hemiplegic gait. [Subjects and Methods] A multichannel dynamic electrical stimulation system was developed with 8-channel low frequency current generators. Eight male hemiplegic patients were trained for 4 weeks with electric stimulation of the tibia anterior and rectus femoris muscles during walking, which was coupled with active contraction. Kinematic data were collected, and muscle forces of the tibialis anterior and rectus femoris of the affected limbs were analyzed using a musculoskelatal modeling approach before and after training. A paired sample t-test was used to detect the differences between before and after training. [Results] The step length of the affected limb significantly increased after the stimulation was applied. The maximum dorsiflexion angle and maximum knee flexion angle of the affected limb were both increased significantly during stimulation. The maximum muscle forces of both the tibia anterior and rectus femoris increased significantly during stimulation compared with before functional electrical stimulation was applied. [Conclusion] This study established a functional electrical stimulation strategy based on hemiplegic gait analysis and musculoskeletal modeling. The multichannel functional electrical stimulation system successfully corrected foot drop and altered circumduction hemiplegic gait pattern.

  11. Resistance training for activity limitations in older adults with skeletal muscle function deficits: a systematic review

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    Papa EV

    2017-06-01

    Full Text Available Evan V Papa,1 Xiaoyang Dong,2 Mahdi Hassan1 1Department of Rehabilitation Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, People’s Republic of China; 2Department of Physical Therapy, University of North Texas Health Science Center, Fort Worth, TX, USA Abstract: Human aging results in a variety of changes to skeletal muscle. Sarcopenia is the age-associated loss of muscle mass and is one of the main contributors to musculoskeletal impairments in the elderly. Previous research has demonstrated that resistance training can attenuate skeletal muscle function deficits in older adults, however few articles have focused on the effects of resistance training on functional mobility. The purpose of this systematic review was to 1 present the current state of literature regarding the effects of resistance training on functional mobility outcomes for older adults with skeletal muscle function deficits and 2 provide clinicians with practical guidelines that can be used with seniors during resistance training, or to encourage exercise. We set forth evidence that resistance training can attenuate age-related changes in functional mobility, including improvements in gait speed, static and dynamic balance, and fall risk reduction. Older adults should be encouraged to participate in progressive resistance training activities, and should be admonished to move along a continuum of exercise from immobility, toward the recommended daily amounts of activity. Keywords: aging, strength training, sarcopenia, mobility, balance

  12. Dissociation between short-term unloading and resistance training effects on skeletal muscle Na+,K+-ATPase, muscle function, and fatigue in humans.

    Science.gov (United States)

    Perry, Ben D; Wyckelsma, Victoria L; Murphy, Robyn M; Steward, Collene H; Anderson, Mitchell; Levinger, Itamar; Petersen, Aaron C; McKenna, Michael J

    2016-11-01

    Physical training increases skeletal muscle Na + ,K + -ATPase content (NKA) and improves exercise performance, but the effects of inactivity per se on NKA content and isoform abundance in human muscle are unknown. We investigated the effects of 23-day unilateral lower limb suspension (ULLS) and subsequent 4-wk resistance training (RT) on muscle function and NKA in 6 healthy adults, measuring quadriceps muscle peak torque; fatigue and venous [K + ] during intense one-legged cycling exercise; and skeletal muscle NKA content ([ 3 H]ouabain binding) and NKA isoform abundances (immunoblotting) in muscle homogenates (α 1-3 , β 1-2 ) and in single fibers (α 1-3 , β 1 ). In the unloaded leg after ULLS, quadriceps peak torque and cycling time to fatigue declined by 22 and 23%, respectively, which were restored with RT. Whole muscle NKA content and homogenate NKA α 1-3 and β 1-2 isoform abundances were unchanged with ULLS or RT. However, in single muscle fibers, NKA α 3 in type I (-66%, P = 0.006) and β 1 in type II fibers (-40%, P = 0.016) decreased after ULLS, with other NKA isoforms unchanged. After RT, NKA α 1 (79%, P = 0.004) and β 1 (35%, P = 0.01) increased in type II fibers, while α 2 (76%, P = 0.028) and α 3 (142%, P = 0.004) increased in type I fibers compared with post-ULLS. Despite considerably impaired muscle function and earlier fatigue onset, muscle NKA content and homogenate α 1 and α 2 abundances were unchanged, thus being resilient to inactivity induced by ULLS. Nonetheless, fiber type-specific downregulation with inactivity and upregulation with RT of several NKA isoforms indicate complex regulation of muscle NKA expression in humans. Copyright © 2016 the American Physiological Society.

  13. Respiratory muscle dysfunction in animal models of hypoxic disease: antioxidant therapy goes from strength to strength

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    O'Halloran KD

    2017-07-01

    Full Text Available Ken D O’Halloran,1 Philip Lewis2 1Department of Physiology, School of Medicine, University College Cork, Cork, Ireland; 2Institute and Policlinic for Occupational Medicine, Environmental Medicine and Preventative Research, University Hospital of Cologne, Germany Abstract: The striated muscles of breathing play a critical role in respiratory homeostasis governing blood oxygenation and pH regulation. Upper airway dilator and thoracic pump muscles retain a remarkable capacity for plasticity throughout life, both in health and disease states. Hypoxia, whatever the cause, is a potent driver of respiratory muscle remodeling with evidence of adaptive and maladaptive outcomes for system performance. The pattern, duration, and intensity of hypoxia are key determinants of respiratory muscle structural-, metabolic-, and functional responses and adaptation. Age and sex also influence respiratory muscle tolerance of hypoxia. Redox stress emerges as the principal protagonist driving respiratory muscle malady in rodent models of hypoxic disease. There is a growing body of evidence demonstrating that antioxidant intervention alleviates hypoxia-induced respiratory muscle dysfunction, and that N-acetyl cysteine, approved for use in humans, is highly effective in preventing hypoxia-induced respiratory muscle weakness and fatigue. We posit that oxygen homeostasis is a key driver of respiratory muscle form and function. Hypoxic stress is likely a major contributor to respiratory muscle malaise in diseases of the lungs and respiratory control network. Animal studies provide an evidence base in strong support of the need to explore adjunctive antioxidant therapies for muscle dysfunction in human respiratory disease. Keywords: respiratory muscle, diaphragm, upper airway, hypoxia, antioxidants, N-acetyl-cysteine, OSA, COPD

  14. Renin-angiotensin system: an old player with novel functions in skeletal muscle.

    Science.gov (United States)

    Cabello-Verrugio, Claudio; Morales, María Gabriela; Rivera, Juan Carlos; Cabrera, Daniel; Simon, Felipe

    2015-05-01

    Skeletal muscle is a tissue that shows the most plasticity in the body; it can change in response to physiological and pathological stimuli. Among the diseases that affect skeletal muscle are myopathy-associated fibrosis, insulin resistance, and muscle atrophy. A common factor in these pathologies is the participation of the renin-angiotensin system (RAS). This system can be functionally separated into the classical and nonclassical RAS axis. The main components of the classical RAS pathway are angiotensin-converting enzyme (ACE), angiotensin II (Ang-II), and Ang-II receptors (AT receptors), whereas the nonclassical axis is composed of ACE2, angiotensin 1-7 [Ang (1-7)], and the Mas receptor. Hyperactivity of the classical axis in skeletal muscle has been associated with insulin resistance, atrophy, and fibrosis. In contrast, current evidence supports the action of the nonclassical RAS as a counter-regulator axis of the classical RAS pathway in skeletal muscle. In this review, we describe the mechanisms involved in the pathological effects of the classical RAS, advances in the use of pharmacological molecules to inhibit this axis, and the beneficial effects of stimulation of the nonclassical RAS pathway on insulin resistance, atrophy, and fibrosis in skeletal muscle. © 2015 Wiley Periodicals, Inc.

  15. Effect of kinesio taping on the isokinetic muscle function in football athletes with a knee injury.

    Science.gov (United States)

    Hong, SoonKwon; Shim, JeMyung; Kim, SungJoong; Namkoong, Seung; Roh, HyoLyun

    2016-01-01

    [Purpose] The purpose of this study was to determine the difference in isokinetic muscle function in football athletes with a knee injury with and without kinesio taping. [Subjects] The subjects for this study were 10 football athletes (males) with a knee injury. [Methods] Measurements were performed by using Cybex dynamometer under uniform motion before and after the application of kinesio tape to the quadriceps and hamstring muscle. Maximal concentric knee extension and flexion at three angular velocities (60°/s, 120°/s, and 180°/s) were measured. [Results] A significant difference was found in peak torque and total work of the flexion at 120°/s and 180°/s, as well as in the average power of extension at 180°/s. [Conclusion] Though it is not the main therapy for muscle function in football athletes with injury, kinesio taping was an effective adjunct therapy.

  16. Muscle mass, isokinetic torque, and functional capacity in women with osteoarthritis of the knee.

    Science.gov (United States)

    Gür, Hakan; Cakin, Nilgün

    2003-10-01

    To investigate the relations between cross-sectional area and concentric and eccentric torques in the quadriceps and hamstring muscles and to determine how functional capacity relates to pain, muscle mass, and concentric and eccentric knee torques in women who have bilateral osteoarthritis (OA) of the knee. Randomized, descriptive study. A university exercise physiology laboratory in Turkey. Eighteen women with bilateral knee OA (grades 2 or 3) graded radiographically. Not applicable. Selected functional tests included the 15-m walk, rising from a chair, descending stairs, and stair climbing. Pain during the functional tests was subjectively measured on an 11-point scale (range, 0-10). Concentric and eccentric torques of the quadriceps and hamstring muscles were measured by isokinetic dynamometry with angular velocities of 60 degrees, 120 degrees, and 180 degrees /s; cross-sectional areas of the quadriceps and hamstring muscles were measured by computed tomography. Eccentric torque was significantly (P range, quadriceps (range, 16%-100%) and hamstring (range, 50%-158%) muscles at all angular velocities. Torque-velocity curves for concentric and eccentric contractions were almost identical to those found in healthy young and elderly people. According to r(2) values, cross-sectional area of the quadriceps and hamstring muscles explained 24% to 61% (r(2) range,.24-.61) and 38% to 51% (r(2) range,.38-.51) of the variations in concentric and eccentric peak torques, respectively. Very small to moderate correlations (.01-.75) were observed among torque at any velocity and the variables of functional capacity and pain. For stair-climbing times, the best predictor variable was the eccentric hamstring to concentric quadriceps torque ratio. For stair descending, it was the concentric hamstring to eccentric quadriceps torque ratios. These torque ratios explained 81% (r(2)=.81) and 61% (r(2)=.61) of the variations, respectively. The findings in a patient group with bilateral OA

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Plasticity of human skeletal muscle: gene expression to in vivo function.

    Science.gov (United States)

    Harridge, Stephen D R

    2007-09-01

    Human skeletal muscle is a highly heterogeneous tissue, able to adapt to the different challenges that may be placed upon it. When overloaded, a muscle adapts by increasing its size and strength through satellite-cell-mediated mechanisms, whereby protein synthesis is increased and new nuclei are added to maintain the myonuclear domain. This process is regulated by an array of mechanical, hormonal and nutritional signals. Growth factors, such as insulin-like growth factor I (IGF-I) and testosterone, are potent anabolic agents, whilst myostatin acts as a negative regulator of muscle mass. Insulin-like growth factor I is unique in being able to stimulate both the proliferation and the differentiation of satellite cells and works as part of an important local repair and adaptive mechanism. Speed of movement, as characterized by maximal velocity of shortening (V(max)), is regulated primarily by the isoform of myosin heavy chain (MHC) contained within a muscle fibre. Human fibres can express three MHCs: MHC-I, -IIa and -IIx, in order of increasing V(max) and maximal power output. Training studies suggest that there is a subtle interplay between the MHC-IIa and -IIx isoforms, with the latter being downregulated by activity and upregulated by inactivity. However, switching between the two main isoforms appears to require significant challenges to a muscle. Upregulation of fast gene programs is caused by prolonged disuse, whilst upregulation of slow gene programs appears to require significant and prolonged activity. The potential mechanisms by which alterations in muscle composition are mediated are discussed. The implications in terms of contractile function of altering muscle phenotype are discussed from the single fibre to the whole muscle level.

  19. Changes in skeletal muscle and tendon structure and function following genetic inactivation of myostatin in rats.

    Science.gov (United States)

    Mendias, Christopher L; Lynch, Evan B; Gumucio, Jonathan P; Flood, Michael D; Rittman, Danielle S; Van Pelt, Douglas W; Roche, Stuart M; Davis, Carol S

    2015-04-15

    Myostatin is a negative regulator of skeletal muscle and tendon mass. Myostatin deficiency has been well studied in mice, but limited data are available on how myostatin regulates the structure and function of muscles and tendons of larger animals. We hypothesized that, in comparison to wild-type (MSTN(+/+) ) rats, rats in which zinc finger nucleases were used to genetically inactivate myostatin (MSTN(Δ/Δ) ) would exhibit an increase in muscle mass and total force production, a reduction in specific force, an accumulation of type II fibres and a decrease and stiffening of connective tissue. Overall, the muscle and tendon phenotype of myostatin-deficient rats was markedly different from that of myostatin-deficient mice, which have impaired contractility and pathological changes to fibres and their extracellular matrix. Extensor digitorum longus and soleus muscles of MSTN(Δ/Δ) rats demonstrated 20-33% increases in mass, 35-45% increases in fibre number, 20-57% increases in isometric force and no differences in specific force. The insulin-like growth factor-1 pathway was activated to a greater extent in MSTN(Δ/Δ) muscles, but no substantial differences in atrophy-related genes were observed. Tendons of MSTN(Δ/Δ) rats had a 20% reduction in peak strain, with no differences in mass, peak stress or stiffness. The general morphology and gene expression patterns were similar between tendons of both genotypes. This large rodent model of myostatin deficiency did not have the negative consequences to muscle fibres and extracellular matrix observed in mouse models, and suggests that the greatest impact of myostatin in the regulation of muscle mass may not be to induce atrophy directly, but rather to block hypertrophy signalling. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  20. Age Differences in Dynamic Fatigability and Variability of Arm and Leg Muscles: Associations with Physical Function

    Science.gov (United States)

    Senefeld, Jonathon; Yoon, Tejin; Hunter, Sandra K.

    2016-01-01

    Introduction It is not known whether the age-related increase in fatigability of fast dynamic contractions in lower limb muscles also occurs in upper limb muscles. We compared age-related fatigability and variability of maximal-effort repeated dynamic contractions in the knee extensor and elbow flexor muscles; and determined associations between fatigability, variability of velocity between contractions and functional performance. Methods 35 young (16 males; 21.0±2.6 years) and 32 old (18 males; 71.3±6.2 years) adults performed a dynamic fatiguing task involving 90 maximal-effort, fast, concentric, isotonic contractions (1 contraction/3 s) with a load equivalent to 20% maximal voluntary isometric contraction (MVIC) torque with the elbow flexor and knee extensor muscles on separate days. Old adults also performed tests of balance and walking endurance. Results Old adults had greater fatigue-related reductions in peak velocity compared with young adults for both the elbow flexor and knee extensor muscles (P0.05). Old adults had greater variability of peak velocity during the knee extensor, but not during the elbow flexor fatiguing task. The age difference in fatigability was greater for the knee extensor muscles (35.9%) compared with elbow flexor muscles (9.7%, Pmuscles was associated with greater walking endurance (r=−0.34, P=0.048) and balance (r=−0.41, P=0.014) among old adults. Conclusions An age-related increase in fatigability of a dynamic fatiguing task was greater for the knee extensor compared with the elbow flexor muscles in males and females, and greater fatigability was associated with lesser walking endurance and balance. PMID:27989926

  1. ALTERATION OF MUSCLE FUNCTION AFTER ELECTRICAL STIMULATION BOUT OF KNEE EXTENSORS AND FLEXORS

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    Marc Vanderthommen

    2012-12-01

    Full Text Available The purpose was to study the effects on muscle function of an electrical stimulation bout applied unilaterally on thigh muscles in healthy male volunteers. One group (ES group, n = 10 received consecutively 100 isometric contractions of quadriceps and 100 isometric contractions of hamstrings (on-off ratio 6-6 s induced by neuromuscular electrical stimulations (NMES. Changes in muscle torque, muscle soreness (0-10 VAS, muscle stiffness and serum creatine kinase (CK activity were assessed before the NMES exercise (pre-ex as well as 24h (d+1, 48h (d+2 and 120h (d+5 after the bout. A second group (control group, n = 10 were submitted to the same test battery than the ES group and with the same time-frame. The between-group comparison indicated a significant increase in VAS scores and in serum levels of CK only in the ES group. In the ES group, changes were more pronounced in hamstrings than in quadriceps and peaked at d+2 (quadriceps VAS scores = 2.20 ± 1.55 a.u. (0 at pre-ex; hamstrings VAS scores = 3.15 ± 2.14 a.u. (0 at pre-ex; hip flexion angle = 62 ± 5° (75 ± 6° at pre-ex; CK activity = 3021 ± 2693 IU·l-1 (136 ± 50 IU·l-1 at pre-ex. The results of the present study suggested the occurrence of muscle damage that could have been induced by the peculiar muscle recruitment in NMES and the resulting overrated mechanical stress. The sensitivity to the damaging effects of NMES appeared higher in the hamstrings than in quadriceps muscles

  2. Physical activity unveils the relationship between mitochondrial energetics, muscle quality, and physical function in older adults.

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    Distefano, Giovanna; Standley, Robert A; Zhang, Xiaolei; Carnero, Elvis A; Yi, Fanchao; Cornnell, Heather H; Coen, Paul M

    2018-01-24

    The concept of mitochondrial dysfunction in ageing muscle is highly controversial. In addition, emerging evidence suggests that reduced muscle oxidative capacity and efficiency underlie the aetiology of mobility loss in older adults. Here, we hypothesized that studying well-phenotyped older cohorts across a wide range of physical activity would unveil a range of mitochondrial function in skeletal muscle and in turn allow us to more clearly examine the impact of age per se on mitochondrial energetics. This also enabled us to more clearly define the relationships between mitochondrial energetics and muscle lipid content with clinically relevant assessments of muscle and physical function. Thirty-nine volunteers were recruited to the following study groups: young active (YA, n = 2 women/8 men, age = 31.2 ± 5.4 years), older active (OA, n = 2 women/8 men, age = 67.5 ± 2.7 years), and older sedentary (OS, n = 8 women/11 men, age = 70.7 ± 4.7 years). Participants completed a graded exercise test to determine fitness (VO 2 peak), a submaximal exercise test to determine exercise efficiency, and daily physical activity was recorded using a tri-axial armband accelerometer. Mitochondrial energetics were determined by (i) 31 P magnetic resonance spectroscopy and (ii) respirometry of fibre bundles from vastus lateralis biopsies. Quadriceps function was assessed by isokinetic dynamometry and physical function by the short physical performance battery and stair climb test. Daily physical activity energy expenditure was significantly lower in OS, compared with YA and OA groups. Despite fitness being higher in YA compared with OA and OS, mitochondrial respiration, maximum mitochondrial capacity, Maximal ATP production/Oxygen consumption (P/O) ratio, and exercise efficiency were similar in YA and OA groups and were significantly lower in OS. P/O ratio was correlated with exercise efficiency. Time to complete the stair climb and repeated chair stand tests were

  3. The role of visual feedback in respiratory muscle activation and pulmonary function.

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    Park, Han-Kyu; Kim, Yeong-Ju; Kim, Tae-Ho

    2015-09-01

    [Purpose] It is well known that visual feedback is an important factor contributing to balance and postural control. Nevertheless, there has been little discussion about the effects of visual feedback on pulmonary function. This study was conducted to investigate the role of visual feedback on respiratory muscle activation and pulmonary function. [Subjects and Methods] The subjects were 37 healthy adults who consented to participate in this study. The study measured the muscular activation of the trunk and pulmonary function according to the absence or presence of visual feedback. [Results] The results revealed significant changes in muscular activation and pulmonary function with the use of visual feedback. [Conclusion] These findings suggest that visual feedback may play a role in increasing respiratory muscle activity and pulmonary function.

  4. Rehabilitative ultrasound imaging of pelvic floor muscle function.

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    Whittaker, Jackie L; Thompson, Judith A; Teyhen, Deydre S; Hodges, Paul

    2007-08-01

    This commentary provides an overview of the current concepts and evidence related to rehabilitative ultrasound imaging of pelvic floor (levator ani) function. As this is an emerging topic, the goal is to provide a basic understanding of ultrasound imaging applications related to levator ani function: the available quantitative and qualitative information, the limitations, as well as how ultrasound imaging can be incorporated as a form of biofeedback during rehabilitation. Furthermore, as the ability to compile and compare existing evidence depends on the degree of similarity in methodology by investigators, this commentary highlights points of consideration and provides guidelines, as well as an agenda, for future investigation.

  5. Expression of a dominant negative CELF protein in vivo leads to altered muscle organization, fiber size, and subtype.

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    Dara S Berger

    2011-04-01

    Full Text Available CUG-BP and ETR-3-like factor (CELF proteins regulate tissue- and developmental stage-specific alternative splicing in striated muscle. We previously demonstrated that heart muscle-specific expression of a nuclear dominant negative CELF protein in transgenic mice (MHC-CELFΔ effectively disrupts endogenous CELF activity in the heart in vivo, resulting in impaired cardiac function. In this study, transgenic mice that express the dominant negative protein under a skeletal muscle-specific promoter (Myo-CELFΔ were generated to investigate the role of CELF-mediated alternative splicing programs in normal skeletal muscle.Myo-CELFΔ mice exhibit modest changes in CELF-mediated alternative splicing in skeletal muscle, accompanied by a reduction of endomysial and perimysial spaces, an increase in fiber size variability, and an increase in slow twitch muscle fibers. Weight gain and mean body weight, total number of muscle fibers, and overall muscle strength were not affected.Although these findings demonstrate that CELF activity contributes to the normal alternative splicing of a subset of muscle transcripts in vivo, the mildness of the effects in Myo-CELFΔ muscles compared to those in MHC-CELFΔ hearts suggests CELF activity may be less determinative for alternative splicing in skeletal muscle than in heart muscle. Nonetheless, even these small changes in CELF-mediated splicing regulation were sufficient to alter muscle organization and muscle fiber properties affected in myotonic dystrophy. This lends further evidence to the hypothesis that dysregulation of CELF-mediated alternative splicing programs may be responsible for the disruption of these properties during muscle pathogenesis.

  6. Test-retest reliability of maximal leg muscle power and functional performance measures in patients with severe osteoarthritis (OA)

    DEFF Research Database (Denmark)

    Villadsen, Allan; Roos, Ewa M.; Overgaard, Søren

    Abstract : Purpose To evaluate the reliability of single-joint and multi-joint maximal leg muscle power and functional performance measures in patients with severe OA. Background Muscle power, taking both strength and velocity into account, is a more functional measure of lower extremity muscle...... and scheduled for unilateral total hip (n=9) or knee (n=11) replacement. Patients underwent a test battery on two occasions separated by approximately one week (range 7 to 11 days). Muscle power was measured using: 1. A linear encoder, unilateral lower limb isolated single-joint dynamic movement, e.g. knee...... activity compared with the traditionally used isometric and/or isokinetic muscle strength. More functional measures are preferred to determine muscle function and as outcomes in exercise studies in patients with OA. Methods Subjects: 20 patients (mean age 68.7±7.2, BMI 29.0±3.9) diagnosed with severe OA...

  7. Respiratory muscle function during a six-week period of normocapnic hyperpnoea training.

    Science.gov (United States)

    Walker, David Johannes; Ertl, Thomas; Walterspacher, Stephan; Schlager, Daniel; Roecker, Kai; Windisch, Wolfram; Kabitz, Hans-Joachim

    2013-08-15

    Respiratory muscle endurance training (normocapnic hyperpnoea, RMET) improves maximal volitional ventilation (MVV) and respiratory muscle endurance while volitionally-assessed respiratory muscle strength remains unchanged (prior-to-post comparison). What remains unclear is how respiratory muscle function changes/adapts during a defined period of RMET in highly-trained subjects. This study assessed respiratory muscle function during a six-week period of RMET in 13 highly-trained, healthy subjects. Weekly-assessed twitch mouth pressure (prior/post 2.20 ± 0.41 kPa vs. 2.43 ± 0.61 kPa; p=0.14); twitch transdiaphragmatic pressure (prior/post 3.04 ± 0.58 kPa vs. 3.13 ± 0.48 kPa; p=0.58) and maximal inspiratory pressure (prior/post 12.6 ± 3.6 kPa vs. 13.9 ± 3.8 kPa; p=0.06) did not increase. MVV (prior/post 175 ± 18 l/min vs. 207 ± 30 l/min; p=0.001), sniff nasal pressure (prior/post 11.8 ± 2.8 kPa vs. 14.0 ± 2.9 kPa; p=0.003) and maximal expiratory pressure (prior/post 16.9 ± 5.8 kPa vs. 20.9 ± 4.9 kPa; p=0.006) each increased. In conclusion, non-volitionally assessed diaphragmatic strength does not increase during six weeks of RMET in highly-trained subjects, while expiratory muscle strength and MVV rose. Future studies should clarify if these findings apply when assessed during respiratory muscle strength rather than endurance training. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Respiratory Muscle Training Improves Diaphragm Citrate Synthase Activity and Hemodynamic Function in Rats with Heart Failure.

    Science.gov (United States)

    Jaenisch, Rodrigo Boemo; Bertagnolli, Mariane; Borghi-Silva, Audrey; Arena, Ross; Lago, Pedro Dal

    2017-01-01

    Enhanced respiratory muscle strength in patients with heart failure positively alters the clinical trajectory of heart failure. In an experimental model, respiratory muscle training in rats with heart failure has been shown to improve cardiopulmonary function through mechanisms yet to be entirely elucidated. The present report aimed to evaluate the respiratory muscle training effects in diaphragm citrate synthase activity and hemodynamic function in rats with heart failure. Wistar rats were divided into four experimental groups: sedentary sham (Sed-Sham, n=8), trained sham (RMT-Sham, n=8), sedentary heart failure (Sed-HF, n=7) and trained heart failure (RMT-HF, n=7). The animals were submitted to a RMT protocol performed 30 minutes a day, 5 days/week, for 6 weeks. In rats with heart failure, respiratory muscle training decreased pulmonary congestion and right ventricular hypertrophy. Deleterious alterations in left ventricular pressures, as well as left ventricular contractility and relaxation, were assuaged by respiratory muscle training in heart failure rats. Citrate synthase activity, which was significantly reduced in heart failure rats, was preserved by respiratory muscle training. Additionally, a negative correlation was found between citrate synthase and left ventricular end diastolic pressure and positive correlation was found between citrate synthase and left ventricular systolic pressure. Respiratory muscle training produces beneficial adaptations in the diaphragmatic musculature, which is linked to improvements in left ventricular hemodynamics and blood pressure in heart failure rats. The RMT-induced improvements in cardiac architecture and the oxidative capacity of the diaphragm may improve the clinical trajectory of patients with heart failure.

  9. Chronic dietary supplementation with soy protein improves muscle function in rats.

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    Ramzi J Khairallah

    Full Text Available Athletes as well as elderly or hospitalized patients use dietary protein supplementation to maintain or grow skeletal muscle. It is recognized that high quality protein is needed for muscle accretion, and can be obtained from both animal and plant-based sources. There is interest to understand whether these sources differ in their ability to maintain or stimulate muscle growth and function. In this study, baseline muscle performance was assessed in 50 adult Sprague-Dawley rats after which they were assigned to one of five semi-purified "Western" diets (n = 10/group differing only in protein source, namely 19 kcal% protein from either milk protein isolate (MPI, whey protein isolate (WPI, soy protein isolate (SPI, soy protein concentrate (SPC or enzyme-treated soy protein (SPE. The diets were fed for 8 weeks at which point muscle performance testing was repeated and tissues were collected for analysis. There was no significant difference in food consumption or body weights over time between the diet groups nor were there differences in terminal organ and muscle weights or in serum lipids, creatinine or myostatin. Compared with MPI-fed rats, rats fed WPI and SPC displayed a greater maximum rate of contraction using the in vivo measure of muscle performance (p<0.05 with increases ranging from 13.3-27.5% and 22.8-29.5%, respectively at 60, 80, 100 and 150 Hz. When the maximum force was normalized to body weight, SPC-fed rats displayed increased force compared to MPI (p<0.05, whereas when normalized to gastrocnemius weight, WPI-fed rats displayed increased force compared to MPI (p<0.05. There was no difference between groups using in situ muscle performance. In conclusion, soy protein consumption, in high-fat diet, resulted in muscle function comparable to whey protein and improved compared to milk protein. The benefits seen with soy or whey protein were independent of changes in muscle mass or fiber cross-sectional area.

  10. Quantification of Na+,K+ pumps and their transport rate in skeletal muscle: functional significance.

    Science.gov (United States)

    Clausen, Torben

    2013-10-01

    During excitation, muscle cells gain Na(+) and lose K(+), leading to a rise in extracellular K(+) ([K(+)]o), depolarization, and loss of excitability. Recent studies support the idea that these events are important causes of muscle fatigue and that full use of the Na(+),K(+)-ATPase (also known as the Na(+),K(+) pump) is often essential for adequate clearance of extracellular K(+). As a result of their electrogenic action, Na(+),K(+) pumps also help reverse depolarization arising during excitation, hyperkalemia, and anoxia, or from cell damage resulting from exercise, rhabdomyolysis, or muscle diseases. The ability to evaluate Na(+),K(+)-pump function and the capacity of the Na(+),K(+) pumps to fill these needs require quantification of the total content of Na(+),K(+) pumps in skeletal muscle. Inhibition of Na(+),K(+)-pump activity, or a decrease in their content, reduces muscle contractility. Conversely, stimulation of the Na(+),K(+)-pump transport rate or increasing the content of Na(+),K(+) pumps enhances muscle excitability and contractility. Measurements of [(3)H]ouabain binding to skeletal muscle in vivo or in vitro have enabled the reproducible quantification of the total content of Na(+),K(+) pumps in molar units in various animal species, and in both healthy people and individuals with various diseases. In contrast, measurements of 3-O-methylfluorescein phosphatase activity associated with the Na(+),K(+)-ATPase may show inconsistent results. Measurements of Na(+) and K(+) fluxes in intact isolated muscles show that, after Na(+) loading or intense excitation, all the Na(+),K(+) pumps are functional, allowing calculation of the maximum Na(+),K(+)-pumping capacity, expressed in molar units/g muscle/min. The activity and content of Na(+),K(+) pumps are regulated by exercise, inactivity, K(+) deficiency, fasting, age, and several hormones and pharmaceuticals. Studies on the α-subunit isoforms of the Na(+),K(+)-ATPase have detected a relative increase in their

  11. Quantification of Na+,K+ pumps and their transport rate in skeletal muscle: Functional significance

    Science.gov (United States)

    2013-01-01

    During excitation, muscle cells gain Na+ and lose K+, leading to a rise in extracellular K+ ([K+]o), depolarization, and loss of excitability. Recent studies support the idea that these events are important causes of muscle fatigue and that full use of the Na+,K+-ATPase (also known as the Na+,K+ pump) is often essential for adequate clearance of extracellular K+. As a result of their electrogenic action, Na+,K+ pumps also help reverse depolarization arising during excitation, hyperkalemia, and anoxia, or from cell damage resulting from exercise, rhabdomyolysis, or muscle diseases. The ability to evaluate Na+,K+-pump function and the capacity of the Na+,K+ pumps to fill these needs require quantification of the total content of Na+,K+ pumps in skeletal muscle. Inhibition of Na+,K+-pump activity, or a decrease in their content, reduces muscle contractility. Conversely, stimulation of the Na+,K+-pump transport rate or increasing the content of Na+,K+ pumps enhances muscle excitability and contractility. Measurements of [3H]ouabain binding to skeletal muscle in vivo or in vitro have enabled the reproducible quantification of the total content of Na+,K+ pumps in molar units in various animal species, and in both healthy people and individuals with various diseases. In contrast, measurements of 3-O-methylfluorescein phosphatase activity associated with the Na+,K+-ATPase may show inconsistent results. Measurements of Na+ and K+ fluxes in intact isolated muscles show that, after Na+ loading or intense excitation, all the Na+,K+ pumps are functional, allowing calculation of the maximum Na+,K+-pumping capacity, expressed in molar units/g muscle/min. The activity and content of Na+,K+ pumps are regulated by exercise, inactivity, K+ deficiency, fasting, age, and several hormones and pharmaceuticals. Studies on the α-subunit isoforms of the Na+,K+-ATPase have detected a relative increase in their number in response to exercise and the glucocorticoid dexamethasone but have not

  12. Fast skeletal muscle troponin activator tirasemtiv increases muscle function and performance in the B6SJL-SOD1G93A ALS mouse model.

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    Darren T Hwee

    Full Text Available Amyotrophic Lateral Sclerosis (ALS is a motor neuron disease characterized by progressive motor neuron loss resulting in muscle atrophy, declining muscle function, and eventual paralysis. Patients typically die from respiratory failure 3 to 5 years from the onset of symptoms. Tirasemtiv is a fast skeletal troponin activator that sensitizes the sarcomere to calcium; this mechanism of action amplifies the response of muscle to neuromuscular input producing greater force when nerve input is reduced. Here, we demonstrate that a single dose of tirasemtiv significantly increases submaximal isometric force, forelimb grip strength, grid hang time, and rotarod performance in a female transgenic mouse model (B6SJL-SOD1 G93A of ALS with functional deficits. Additionally, diaphragm force and tidal volume are significantly higher in tirasemtiv-treated female B6SJL-SOD1 G93A mice. These results support the potential of fast skeletal troponin activators to improve muscle function in neuromuscular diseases.

  13. Muscle function decline and mitochondria changes in middle age precede sarcopenia in mice.

    Science.gov (United States)

    Del Campo, Andrea; Contreras-Hernández, Ignacio; Castro-Sepúlveda, Mauricio; Campos, Cristian A; Figueroa, Reinaldo; Tevy, María Florencia; Eisner, Verónica; Casas, Mariana; Jaimovich, Enrique

    2018-01-04

    Sarcopenia is the degenerative loss of muscle mass and strength with aging. Although a role of mitochondrial metabolism in muscle function and in the development of many diseases has been described, the role of mitochondrial topology and dynamics in the process of muscle aging is not fully understood. This work shows a time line of changes in both mitochondrial distribution and skeletal muscle function during mice lifespan. We isolated muscle fibers from flexor digitorum brevis of mice of different ages. A fusion-like phenotype of mitochondria, together with a change in orientation perpendicular to the fiber axis was evident in the Adult group compared to Juvenile and Older groups. Moreover, an increase in the contact area between sarcoplasmic reticulum and mitochondria was evident in the same group. Together with the morphological changes, mitochondrial Ca 2+ resting levels were reduced at age 10-14 months and significantly increased in the Older group. This was consistent with a reduced number of mitochondria-to-jSR pairs in the Older group compared to the Juvenile. Our results support the idea of several age-dependent changes in mitochondria that are accentuated in midlife prior to a complete sarcopenic phenotype.

  14. Effects of protein-calorie restriction on mechanical function of hypertrophied cardiac muscle

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    Antônio Carlos Cicogna

    1999-04-01

    Full Text Available OBJECTIVE: To assess the effect of food restriction (FR on hypertrophied cardiac muscle in spontaneously hypertensive rats (SHR. METHODS: Isolated papillary muscle preparations of the left ventricle (LV of 60-day-old SHR and of normotensive Wistar-Kyoto (WKY rats were studied. The rats were fed either an unrestricted diet or FR diet (50% of the intake of the control diet for 30 days. The mechanical function of the muscles was evaluated through monitoring isometric and isotonic contractions. RESULTS: FR caused: 1 reduction in the body weight and LV weight of SHR and WKY rats; 2 increase in the time to peak shortening and the time to peak developed tension (DT in the hypertrophied myocardium of the SHR; 3 diverging changes in the mechanical function of the normal cardiac muscles of WKY rats with reduction in maximum velocity of isotonic shortening and of the time for DT to decrease 50% of its maximum value, and increase of the resting tension and of the rate of tension decline. CONCLUSION: Short-term FR causes prolongation of the contraction time of hypertrophied muscles and paradoxal changes in mechanical performance of normal cardiac fibers, with worsening of the shortening indices and of the resting tension, and improvement of the isometric relaxation.

  15. Conserved and divergent functions of Nfix in skeletal muscle development during vertebrate evolution.

    Science.gov (United States)

    Pistocchi, Anna; Gaudenzi, Germano; Foglia, Efrem; Monteverde, Stefania; Moreno-Fortuny, Artal; Pianca, Alessia; Cossu, Giulio; Cotelli, Franco; Messina, Graziella

    2013-04-01

    During mouse skeletal muscle development, the Nfix gene has a pivotal role in regulating fetal-specific transcription. Zebrafish and mice share related programs for muscle development, although zebrafish develops at a much faster rate. In fact, although mouse fetal muscle fibers form after 15 days of development, in fish secondary muscle fibers form by 48 hours post-fertilization in a process that until now has been poorly characterized mechanically. In this work, we studied the zebrafish ortholog Nfix (nfixa) and its role in the proper switch to the secondary myogenic wave. This allowed us to highlight evolutionarily conserved and divergent functions of Nfix. In fact, the knock down of nfixa in zebrafish blocks secondary myogenesis, as in mouse, but also alters primary slow muscle fiber formation. Moreover, whereas Nfix mutant mice are motile, nfixa knockdown zebrafish display impaired motility that probably depends upon disruption of the sarcoplasmic reticulum. We conclude that, during vertebrate evolution, the transcription factor Nfix lost some specific functions, probably as a consequence of the different environment in which teleosts and mammals develop.

  16. Effects of expiratory muscle training on the frail elderly's respiratory function.

    Science.gov (United States)

    Chigira, Yusuke; Miyazaki, Ikuri; Izumi, Masataka; Oda, Takahiro

    2018-02-01

    [Purpose] The present study examined the effects of expiratory muscle training on elderly day care service users, who had been classified into Care Grades 1 and 2 based on Japan's long-term care insurance system. [Subjects and Methods] Intervention was provided for 29 Care Grade 1 or 2 day care service users. During intervention, expiratory muscle training was performed by slowly expiring using the abdominal muscles and a device after maximal inspiration. Each intervention session lasted for approximately 10 minutes, and 2 sessions were held weekly for 3 months to compare respiratory function test values before and after intervention. [Results] The results were favorable. The vital capacity (VC) and peak expiratory flow (PEF) significantly varied between before and after intervention. [Conclusion] Expiratory muscle training generally improved their respiratory function, particularly their VC and PEF that significantly varied between before and after intervention. As both of these items influence the cough capacity, they may be key to the prevention of aspiration pneumonia. Expiratory muscle training may also contribute to activities of daily living (ADL) and the quality of life, and it is expected to play an important role in rehabilitation as a field of preventive medicine.

  17. Utility and reliability of non-invasive muscle function tests in high-fat-fed mice.

    Science.gov (United States)

    Martinez-Huenchullan, Sergio F; McLennan, Susan V; Ban, Linda A; Morsch, Marco; Twigg, Stephen M; Tam, Charmaine S

    2017-07-01

    What is the central question of this study? Non-invasive muscle function tests have not been validated for use in the study of muscle performance in high-fat-fed mice. What is the main finding and its importance? This study shows that grip strength, hang wire and four-limb hanging tests are able to discriminate the muscle performance between chow-fed and high-fat-fed mice at different time points, with grip strength being reliable after 5, 10 and 20 weeks of dietary intervention. Non-invasive tests are commonly used for assessing muscle function in animal models. The value of these tests in obesity, a condition where muscle strength is reduced, is unclear. We investigated the utility of three non-invasive muscle function tests, namely grip strength (GS), hang wire (HW) and four-limb hanging (FLH), in C57BL/6 mice fed chow (chow group, n = 48) or a high-fat diet (HFD group, n = 48) for 20 weeks. Muscle function tests were performed at 5, 10 and 20 weeks. After 10 and 20 weeks, HFD mice had significantly reduced GS (in newtons; mean ± SD: 10 weeks chow, 1.89 ± 0.1 and HFD, 1.79 ± 0.1; 20 weeks chow, 1.99 ± 0.1 and HFD, 1.75 ± 0.1), FLH [in seconds per gram body weight; median (interquartile range): 10 weeks chow, 2552 (1337-4964) and HFD, 1230 (749-1994); 20 weeks chow, 2048 (765-3864) and HFD, 1036 (717-1855)] and HW reaches [n; median (interquartile range): 10 weeks chow, 4 (2-5) and HFD, 2 (1-3); 20 weeks chow, 3 (1-5) and HFD, 1 (0-2)] and higher falls [n; median (interquartile range): 10 weeks chow, 0 (0-2) and HFD, 3 (1-7); 20 weeks chow, 1 (0-4) and HFD, 8 (5-10)]. Grip strength was reliable in both dietary groups [intraclass correlation coefficient (ICC) = 0.5-0.8; P tests are valuable and reliable tools for assessment of muscle strength and function in high-fat-fed mice. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

  18. Venous muscle pump function during pregnancy. Assessment by ambulatory strain-gauge plethysmography

    DEFF Research Database (Denmark)

    Struckmann, J R; Meiland, H; Bagi, P

    1990-01-01

    The venous muscle pump function was quantitatively assessed through pregnancy weeks 16, 30, 38 and 3 months (week 53) following delivery, in 24 pregnant women who completed a normal pregnancy. A statistically significant increase was found in the mean venous reflux (P less than 0.01), which was r...

  19. Muscular force transmission necessitates a multilevel integrative approach to the analysis of function of skeletal muscle

    NARCIS (Netherlands)

    Huijing, P.A.J.B.M.

    2003-01-01

    Muscular force is transmitted not only to tendon but also to other structures. Connections to extramuscular connective tissue of a compartment and to other muscles are stiff enough to transmit force. The concept of myofascial force transmission is reviewed and some functional consequences

  20. Relationships between Respiratory Muscle Strength and Daily Living Function in Children with Cerebral Palsy

    Science.gov (United States)

    Wang, Hui-Yi; Chen, Chien-Chih; Hsiao, Shih-Fen

    2012-01-01

    Cerebral palsy (CP) is a common childhood disorder characterized by motor disability. Children with CP are at risk of developing significant respiratory problems associated with insufficient respiratory muscle strength. It is crucial to identify important factors which are associated with the limitations in daily living function in such children.…

  1. ASSESSMENT OF IN VIVO MECHANICAL MUSCLE FUNCTION IN PATIENTS WITH OSTEOARTHRITIS (OA) OF THE HIP; RELIABILITY

    DEFF Research Database (Denmark)

    Jensen, Carsten; Overgaard, Søren; Aagaard, Per

    2009-01-01

    INTRODUCTION Muscle function in patients with hip OA is not well-studied. We established a new setup of tests in order to monitor patients before and after surgery with total hip arthroplasty (THA). A test-retest protocol was designed to evaluate the reproducibility of single- and multi-joint str...

  2. Muscle-derived follistatin-like 1 functions to reduce neointimal formation after vascular injury

    NARCIS (Netherlands)

    Miyabe, Megumi; Ohashi, Koji; Shibata, Rei; Uemura, Yusuke; Ogura, Yasuhiro; Yuasa, Daisuke; Kambara, Takahiro; Kataoka, Yoshiyuki; Yamamoto, Takashi; Matsuo, Kazuhiro; Joki, Yusuke; Enomoto, Takashi; Hayakawa, Satoko; Hiramatsu-Ito, Mizuho; Ito, Masanori; van den Hoff, Maurice J. B.; Walsh, Kenneth; Murohara, Toyoaki; Ouchi, Noriyuki

    2014-01-01

    It is well-established that exercise diminishes cardiovascular risk, but whether humoral factors secreted by muscle confer these benefits has not been conclusively shown. We have shown that the secreted protein follistatin-like 1 (Fstl1) has beneficial actions on cardiac and endothelial function.

  3. Pelvic floor muscle function in a general population of women with and without pelvic organ prolapse

    NARCIS (Netherlands)

    M.C.P. Slieker-ten Hove (Marijke); A.L. Pool-Goudzwaard (Annelies); M.J.C. Eijkemans (René); R.P.M. Steegers-Theunissen (Régine); C.W. Burger (Curt); M.E. Vierhout (Mark)

    2010-01-01

    textabstractIntroduction and hypothesis: This study aims to examine the relationship between pelvic floor muscle function (PFMF) and pelvic organ prolapse (POP) in a general female population. Methods: Cross-sectional study on women aged 45-85 years. Validated questionnaires were used to assess

  4. Vascular Function and Regulation of Blood Flow in Resting and Contracting Skeletal Muscle

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin

    importance. The present work provides new insight in to vasodilator interactions important for exercise hyperemia and sheds light on mechanisms important for vascular function and regulation of skeletal muscle blood flow in essential hypertension (high blood pressure) and aging and identifies mechanisms...

  5. Extracellular matrix in airway smooth muscle is associated with dynamics of airway function in asthma

    NARCIS (Netherlands)

    Yick, C. Y.; Ferreira, D. S.; Annoni, R.; von der Thüsen, J. H.; Kunst, P. W.; Bel, E. H.; Lutter, R.; Mauad, T.; Sterk, P. J.

    2012-01-01

    Background: Altered deposition of extracellular matrix (ECM) in the airway smooth muscle (ASM) layer as observed in asthma may influence ASM mechanical properties. We hypothesized that ECM in ASM is associated with airway function in asthma. First, we investigated the difference in ECM expression in

  6. An investigation into the bilateral functional differences of the lower limb muscles in standing and walking.

    Science.gov (United States)

    Liang, Shengyun; Xu, Jiali; Wang, Lei; Zhao, Guoru

    2016-01-01

    To date, most studies use surface electromyographic (sEMG) signals as the control source on active rehabilitation robots, and unilateral data are collected based on the gait symmetry hypothesis, which has caused much controversy. The purpose of this study is to quantitatively evaluate the sEMG activity asymmetry of bilateral muscles in lower extremities during functional tasks. Nine participants were instructed to perform static and dynamic steady state tests. sEMG signals from the tibialis anterior, soleus, medial gastrocnemius and lateral gastrocnemius muscles of bilateral lower extremities were recorded in the experiments. Muscle activities are quantified in terms of sEMG amplitude. We investigated whether characteristics of left limb and the one of the right limb have the same statistical characteristics during functional tasks using The Wilcoxon rank-sum test, and studied dynamic signal irregularity degree for sEMG activities via sample entropy. The total of muscle activities showed significant differences between left limb and right limb during the static steady state (p = 0.000). For dynamic steady states, there were significant differences for most muscle activities between left limb and right limb at different speeds (p = 0.000). Nevertheless, there was no difference between the lateral gastrocnemius for bilateral limb at 2.0 kilometers per hour (p = 0.060). For medial gastrocnemius, differences were not found between left limb and right limb at 1.0 and 3.0 kilometers per hours (p = 0.390 and p = 0.085, respectively). Similarly, there was no difference for soleus at 3.0 kilometers per hour (p = 0.115). The importance of the differences in muscle activities between left limb and right limb were found. These results can potentially be used for evaluating lower limb extremity function of special populations (elderly people or stroke patients) in an objective and simple method.

  7. Smooth Muscle Endothelin B Receptors Regulate Blood Pressure but Not Vascular Function or Neointimal Remodeling.

    Science.gov (United States)

    Miller, Eileen; Czopek, Alicja; Duthie, Karolina M; Kirkby, Nicholas S; van de Putte, Elisabeth E Fransen; Christen, Sibylle; Kimmitt, Robert A; Moorhouse, Rebecca; Castellan, Raphael F P; Kotelevtsev, Yuri V; Kuc, Rhoda E; Davenport, Anthony P; Dhaun, Neeraj; Webb, David J; Hadoke, Patrick W F

    2017-02-01

    The role of smooth muscle endothelin B (ET B ) receptors in regulating vascular function, blood pressure (BP), and neointimal remodeling has not been established. Selective knockout mice were generated to address the hypothesis that loss of smooth muscle ET B receptors would reduce BP, alter vascular contractility, and inhibit neointimal remodeling. ET B receptors were selectively deleted from smooth muscle by crossing floxed ET B mice with those expressing cre-recombinase controlled by the transgelin promoter. Functional consequences of ET B deletion were assessed using myography. BP was measured by telemetry, and neointimal lesion formation induced by femoral artery injury. Lesion size and composition (day 28) were analyzed using optical projection tomography, histology, and immunohistochemistry. Selective deletion of ET B was confirmed by genotyping, autoradiography, polymerase chain reaction, and immunohistochemistry. ET B -mediated contraction was reduced in trachea, but abolished from mesenteric veins, of knockout mice. Induction of ET B -mediated contraction in mesenteric arteries was also abolished in these mice. Femoral artery function was unaltered, and baseline BP modestly elevated in smooth muscle ET B knockout compared with controls (+4.2±0.2 mm Hg; P<0.0001), but salt-induced and ET B blockade-mediated hypertension were unaltered. Circulating endothelin-1 was not altered in knockout mice. ET B -mediated contraction was not induced in femoral arteries by incubation in culture medium or lesion formation, and lesion size was not altered in smooth muscle ET B knockout mice. In the absence of other pathology, ET B receptors in vascular smooth muscle make a small but significant contribution to ET B -dependent regulation of BP. These ET B receptors have no effect on vascular contraction or neointimal remodeling. © 2016 The Authors.

  8. Functional Capacity in Adults With Cerebral Palsy: Lower Limb Muscle Strength Matters.

    Science.gov (United States)

    Gillett, Jarred G; Lichtwark, Glen A; Boyd, Roslyn N; Barber, Lee A

    2018-02-10

    To investigate the relation between lower limb muscle strength, passive muscle properties, and functional capacity outcomes in adults with cerebral palsy (CP). Cross-sectional study. Tertiary institution biomechanics laboratory. Adults with spastic-type CP (N=33; mean age, 25y; range, 15-51y; mean body mass, 70.15±21.35kg) who were either Gross Motor Function Classification System (GMFCS) level I (n=20) or level II (n=13). Not applicable. Six-minute walk test (6MWT) distance (m), lateral step-up (LSU) test performance (total repetitions), timed up-stairs (TUS) performance (s), maximum voluntary isometric strength of plantar flexors (PF) and dorsiflexors (DF) (Nm.kg -1 ), and passive ankle joint and muscle stiffness. Maximum isometric PF strength independently explained 61% of variance in 6MWT performance, 57% of variance in LSU test performance, and 50% of variance in TUS test performance. GMFCS level was significantly and independently related to all 3 functional capacity outcomes, and age was retained as a significant independent predictor of LSU and TUS test performance. Passive medial gastrocnemius muscle fascicle stiffness and ankle joint stiffness were not significantly related to functional capacity measures in any of the multiple regression models. Low isometric PF strength was the most important independent variable related to distance walked on the 6MWT, fewer repetitions on the LSU test, and slower TUS test performance. These findings suggest lower isometric muscle strength contributes to the decline in functional capacity in adults with CP. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  9. A function for filamentous alpha-smooth muscle actin: Retardation of motility in human breast fibroblasts

    DEFF Research Database (Denmark)

    Rønnov-Jessen, Lone; Petersen, Ole William

    1996-01-01

    Actins are known to comprise six mammalian isoforms of which beta- and gamma-nonmuscle actins are present in all cells, whereas alpha-smooth muscle (alpha-sm) actin is normally restricted to cells of the smooth muscle lineages. alpha-Sm actin has been found also to be expressed transiently in cer...... of less prominent focal adhesions as revealed by immunofluorescence staining against vinculin, talin, and beta1-integrin. We propose that an important function of filamentous alpha-sm actin is to immobilize the cells....

  10. The role of PGC-1alpha on mitochondrial function and apoptotic susceptibility in muscle

    DEFF Research Database (Denmark)

    Adhihetty, Peter J; Uguccioni, Giulia; Leick, Lotte

    2009-01-01

    Mitochondria are critical for cellular bioenergetics, and they mediate apoptosis within cells. We used whole body peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) knockout (KO) animals to investigate its role on organelle function, apoptotic signaling, and cytochrome......-c oxidase activity, an indicator of mitochondrial content, in muscle and other tissues (brain, liver, and pancreas). Lack of PGC-1alpha reduced mitochondrial content in all muscles (17-44%; P liver, and pancreas. However, the tissue expression of proteins involved...

  11. Effects of ageing on single muscle fibre contractile function following short-term immobilisation

    DEFF Research Database (Denmark)

    Hvid, Lars G; Ørtenblad, Niels; Aagaard, Per

    2011-01-01

    Very little attention has been given to the combined effect of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...... properties of single muscle fibres (n=378) from vastus lateralis of 9 young (24 ± 1 years) and 8 old (67 ± 2 years) healthy men with comparable levels of physical activity. Prior to immobilisation, MHC IIa fibres produced higher maximum Ca2+-activated force (approx. 32%) and specific force (approx. 33......%) and had lower Ca2+ sensitivity than MHC I fibres (p...

  12. Development of jaw muscles' function in rats fed a kneaded diet

    OpenAIRE

    Koichi, IKEDA; Department of Orthodontics, Kagoshima University Dental School

    1998-01-01

    To clarify the effect of chewing foods on the development of jaw muscles' function, 41 Wister male rats were divided into the solid (group S, n=20) and the kneaded (group K, n=21) diet groups at 16 days of age and fed their respective diets till the end of the experiment. At 5, 8 and 11 weeks of age, electromyograms of the masseter (Ma), medial pterygoid (Mp), temporal (Tm) and digastric muscles (Di) were recorded when both groups intook and chewed the solid diet. Results indicated that : 1) ...

  13. Effect of Dorsiflexor Muscle Strengthening Using Russian Currents on Balance and Function in Elderly

    OpenAIRE

    Sonia Singh; N K Multani

    2013-01-01

    Balance difficulties are one of the major causes of altered mobility and functional decline in the elderly. Over the past 20 years, a considerable amount of research has been conducted to determine the relationship between balance control and motor or sensory system function in order to understand the causes of falling and to create effective strategies to prevent falls in elderly people The present study was done to determine the effectiveness of dorsiflexor muscle strengthening using Russia...

  14. Association of circulating angiotensin converting enzyme activity with respiratory muscle function in infants

    Directory of Open Access Journals (Sweden)

    Onufriou Anny

    2010-05-01

    Full Text Available Abstract Background Angiotensin converting enzyme (ACE gene contains a polymorphism, consisting of either the presence (I or absence (D of a 287 base pair fragment. Deletion (D is associated with increased circulating ACE (cACE activity. It has been suggested that the D-allele of ACE genotype is associated with power-oriented performance and that cACE activity is correlated with muscle strength. Respiratory muscle function may be similarly influenced. Respiratory muscle strength in infants can be assessed specifically by measurement of the maximum inspiratory pressure during crying (Pimax. Pressure-time index of the respiratory muscles (PTImus is a non-invasive method, which assesses the load to capacity ratio of the respiratory muscles. The objective of this study was to determine whether increased cACE activity in infants could be related to greater respiratory muscle strength and to investigate the potential association of cACE with PTImus measurements as well as the association of ACE genotypes with cACE activity and respiratory muscle strength in this population. Methods Serum ACE activity was assayed by using a UV-kinetic method. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pimean/Pimax × (Ti/Ttot, where Pimean was the mean inspiratory pressure estimated from airway pressure, generated 100 milliseconds after an occlusion (P0.1, Pimax was the maximum inspiratory pressure and Ti/Ttot was the ratio of the inspiratory time to the total respiratory cycle time. Pimax was the largest pressure generated during brief airway occlusions performed at the end of a spontaneous crying effort. Results A hundred and ten infants were studied. Infants with D/D genotype had significantly higher serum ACE activity than infants with I/I or I/D genotypes. cACE activity was significantly related to Pimax and inversely related to PTImus. No association between ACE genotypes and

  15. Comparison of complications and functional results of standard posterolateral thoracotomy with muscle sparing thoracotomy

    Directory of Open Access Journals (Sweden)

    Peiravy Sereshke H

    2009-10-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: Standard thoracotomy necessitates division of thoracic large muscles leading to pain and impaired respiratory movements; muscle sparing postero-lateral thoracotomy has been suggested as an alternative to reduce the aforementioned effect. The aim of this study was to compare muscle saving posterolateral thoracotomy with standard thoracotomy."n"nMethods: This study was a clinical trial. All patients who were candidates for elective thoracotomy were included and divided into two groups of muscle saving thoracotomy and standard thoracotomy randomly. Required time for opening and closing the chest, amount of prescribed narcotics, shoulder movements (flexion, extension, abduction and internal rotation, pulmonary function (FVC, FEV1, VC, development of seroma, and duration of hospitalization were assessed. Shoulder movements and pulmonary function were measured immediately before operation and 7 days later while pain measured in 1st and 7th post-operative days."n"nResults: 60 patients (42 males entered the study and there were no significant differences regarding age and sex distribution between two groups (p>0.05. Mean duration of opening the chest in muscle saving thoracotomy was significantly longer than

  16. Increasing Agrin Function Antagonizes Muscle Atrophy and Motor Impairment in Spinal Muscular Atrophy

    Directory of Open Access Journals (Sweden)

    Marina Boido

    2018-01-01

    Full Text Available Spinal muscular atrophy (SMA is a pediatric genetic disease, characterized by motor neuron (MN death, leading to progressive muscle weakness, respiratory failure, and, in the most severe cases, to death. Abnormalities at the neuromuscular junction (NMJ have been reported in SMA, including neurofilament (NF accumulation at presynaptic terminals, immature and smaller than normal endplates, reduced transmitter release, and, finally, muscle denervation. Here we have studied the role of agrin in SMAΔ7 mice, the experimental model of SMAII. We observed a 50% reduction in agrin expression levels in quadriceps of P10 SMA mice compared to age-matched WT controls. To counteract such condition, we treated SMA mice from birth onwards with therapeutic agrin biological NT-1654, an active splice variant of agrin retaining synaptogenic properties, which is also resistant to proteolytic cleavage by neurotrypsin. Mice were analyzed for behavior, muscle and NMJ histology, and survival. Motor behavior was significantly improved and survival was extended by treatment of SMA mice with NT-1654. At P10, H/E-stained sections of the quadriceps, a proximal muscle early involved in SMA, showed that NT-1654 treatment strongly prevented the size decrease of muscle fibers. Studies of NMJ morphology on whole-mount diaphragm preparations revealed that NT-1654-treated SMA mice had more mature NMJs and reduced NF accumulation, compared to vehicle-treated SMA mice. We conclude that increasing agrin function in SMA has beneficial outcomes on muscle fibers and NMJs as the agrin biological NT-1654 restores the crosstalk between muscle and MNs, delaying muscular atrophy, improving motor performance and extending survival.

  17. Functional Echomyography: thickness, ecogenicity, contraction and perfusion of the LMN denervated human muscle before and during h-bFES

    Directory of Open Access Journals (Sweden)

    Riccardo Zanato

    2010-03-01

    Full Text Available Permanent denervated muscles were evaluated by ultrasound to monitor changes in morphology, thickness, contraction-relaxation kinetics and perfusion due to the electrical stimulation program of the Rise2-Italy project. In a case of monolateral lesion, morphology and ultrasonographic structure of the denervated muscles changed during the period of stimulation from a pattern typical of complete denervation-induced muscle atrophy to a pattern which might be considered “normal” when detected in an old patient. Thickness improved significantly more in the middle third of the denervated muscle, reaching the same value as the contralateral innervated muscle. Contraction-relaxation kinetics, measured by recording the muscle movements during electrical stimulation, showed an abnormal behavior of the chronically denervated muscle during the relaxation phase, which resulted to be significantly longer than in normal muscle. The long-term denervated muscles analyzed with Echo Doppler showed at rest a low resistance arterial flow that became pulsed during and after electrical stimulation. As expected, the ultra sound measured electrical stimulation-induced hyperemia lasted longer than the stimulation period. The higher than normal energy of the delivered electrical stimuli of the Vienna home-based Functional Electrical Stimulation strategy (h-b FES demonstrate that the explored muscles were still almost completely denervated during the one-year of training. In conclusion, this pilot study confirms the usefulness of Functional Echomyography in the follow-up and the positive effects of h-b FES of denervated muscles.

  18. Effect of armor and carrying load on body balance and leg muscle function.

    Science.gov (United States)

    Park, Huiju; Branson, Donna; Kim, Seonyoung; Warren, Aric; Jacobson, Bert; Petrova, Adriana; Peksoz, Semra; Kamenidis, Panagiotis

    2014-01-01

    This study investigated the impact of weight and weight distribution of body armor and load carriage on static body balance and leg muscle function. A series of human performance tests were conducted with seven male, healthy, right-handed military students in seven garment conditions with varying weight and weight distributions. Static body balance was assessed by analyzing the trajectory of center of plantar pressure and symmetry of weight bearing in the feet. Leg muscle functions were assessed by analyzing the peak electromyography amplitude of four selected leg muscles during walking. Results of this study showed that uneven weight distribution of garment and load beyond an additional 9 kg impaired static body balance as evidenced by increased sway of center of plantar pressure and asymmetry of weight bearing in the feet. Added weight on non-dominant side of the body created greater impediment to static balance. Increased garment weight also elevated peak EMG amplitude in the rectus femoris to maintain body balance and in the medial gastrocnemius to increase propulsive force. Negative impacts on balance and leg muscle function with increased carrying loads, particularly with an uneven weight distribution, should be stressed to soldiers, designers, and sports enthusiasts. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Modulation of Caspase Activity Regulates Skeletal Muscle Regeneration and Function in Response to Vasopressin and Tumor Necrosis Factor

    Science.gov (United States)

    Moresi, Viviana; Garcia-Alvarez, Gisela; Pristerà, Alessandro; Rizzuto, Emanuele; Albertini, Maria C.; Rocchi, Marco; Marazzi, Giovanna; Sassoon, David; Adamo, Sergio; Coletti, Dario

    2009-01-01

    Muscle homeostasis involves de novo myogenesis, as observed in conditions of acute or chronic muscle damage. Tumor Necrosis Factor (TNF) triggers skeletal muscle wasting in several pathological conditions and inhibits muscle regeneration. We show that intramuscular treatment with the myogenic factor Arg8-vasopressin (AVP) enhanced skeletal muscle regeneration and rescued the inhibitory effects of TNF on muscle regeneration. The functional analysis of regenerating muscle performance following TNF or AVP treatments revealed that these factors exerted opposite effects on muscle function. Principal component analysis showed that TNF and AVP mainly affect muscle tetanic force and fatigue. Importantly, AVP counteracted the effects of TNF on muscle function when delivered in combination with the latter. Muscle regeneration is, at least in part, regulated by caspase activation, and AVP abrogated TNF-dependent caspase activation. The contrasting effects of AVP and TNF in vivo are recapitulated in myogenic cell cultures, which express both PW1, a caspase activator, and Hsp70, a caspase inhibitor. We identified PW1 as a potential Hsp70 partner by screening for proteins interacting with PW1. Hsp70 and PW1 co-immunoprecipitated and co-localized in muscle cells. In vivo Hsp70 protein level was upregulated by AVP, and Hsp70 overexpression counteracted the TNF block of muscle regeneration. Our results show that AVP counteracts the effects of TNF through cross-talk at the Hsp70 level. Therefore, muscle regeneration, both in the absence and in the presence of cytokines may be enhanced by increasing Hsp70 expression. PMID:19440308

  20. Modulation of caspase activity regulates skeletal muscle regeneration and function in response to vasopressin and tumor necrosis factor.

    Directory of Open Access Journals (Sweden)

    Viviana Moresi

    Full Text Available Muscle homeostasis involves de novo myogenesis, as observed in conditions of acute or chronic muscle damage. Tumor Necrosis Factor (TNF triggers skeletal muscle wasting in several pathological conditions and inhibits muscle regeneration. We show that intramuscular treatment with the myogenic factor Arg(8-vasopressin (AVP enhanced skeletal muscle regeneration and rescued the inhibitory effects of TNF on muscle regeneration. The functional analysis of regenerating muscle performance following TNF or AVP treatments revealed that these factors exerted opposite effects on muscle function. Principal component analysis showed that TNF and AVP mainly affect muscle tetanic force and fatigue. Importantly, AVP counteracted the effects of TNF on muscle function when delivered in combination with the latter. Muscle regeneration is, at least in part, regulated by caspase activation, and AVP abrogated TNF-dependent caspase activation. The contrasting effects of AVP and TNF in vivo are recapitulated in myogenic cell cultures, which express both PW1, a caspase activator, and Hsp70, a caspase inhibitor. We identified PW1 as a potential Hsp70 partner by screening for proteins interacting with PW1. Hsp70 and PW1 co-immunoprecipitated and co-localized in muscle cells. In vivo Hsp70 protein level was upregulated by AVP, and Hsp70 overexpression counteracted the TNF block of muscle regeneration. Our results show that AVP counteracts the effects of TNF through cross-talk at the Hsp70 level. Therefore, muscle regeneration, both in the absence and in the presence of cytokines may be enhanced by increasing Hsp70 expression.

  1. The striated muscles in pulmonary arterial hypertension: adaptations beyond the right ventricle

    NARCIS (Netherlands)

    Manders, E.; Rain, S.; Bogaard, H.J.; Handoko, M.L.; Stienen, G.J.M.; Vonk Noordegraaf, A.; Ottenheijm, C.A.C.; de Man, F.S.

    2015-01-01

    Pulmonary arterial hypertension (PAH) is a fatal lung disease characterised by progressive remodelling of the small pulmonary vessels. The daily-life activities of patients with PAH are severely limited by exertional fatigue and dyspnoea. Typically, these symptoms have been explained by right heart

  2. A striated muscle on the hard palate of rodents and rabbits

    Czech Academy of Sciences Publication Activity Database

    Pavlíková, H.; Witter, Kirsti; Míšek, Ivan

    2004-01-01

    Roč. 33, - (2004), s. 96-99 ISSN 0340-2096 R&D Projects: GA ČR GP304/01/P021; GA ČR GA304/02/0448; GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z5045916 Keywords : hard palate * rabbits * rodents Subject RIV: EA - Cell Biology Impact factor: 0.625, year: 2004

  3. High-intensity strength training improves function of chronically painful muscles

    DEFF Research Database (Denmark)

    Andersen, Lars L; Andersen, Christoffer H; Skotte, Jørgen H

    2014-01-01

    AIM: This study investigates consequences of chronic neck pain on muscle function and the rehabilitating effects of contrasting interventions. METHODS: Women with trapezius myalgia (MYA, n = 42) and healthy controls (CON, n = 20) participated in a case-control study. Subsequently MYA were...... randomized to 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 16), or a reference group without physical training (REF, n = 8). Participants performed tests of 100 consecutive cycles of 2 s isometric maximal voluntary contractions (MVC) of shoulder elevation followed...... capacity during repetitive MVC of the trapezius muscle than healthy controls. High-intensity strength training effectively improves strength capacity during repetitive MVC of the painful trapezius muscle....

  4. Localization and function of ATP-sensitive potassium channels in human skeletal muscle

    DEFF Research Database (Denmark)

    Nielsen, Jens Jung; Kristensen, Michael; Hellsten, Ylva

    2003-01-01

    The present study investigated the localization of ATP-sensitive K+ (KATP) channels in human skeletal muscle and the functional importance of these channels for human muscle K+ distribution at rest and during muscle activity. Membrane fractionation based on the giant vesicle technique...... or the sucrose-gradient technique in combination with Western blotting demonstrated that the KATP channels are mainly located in the sarcolemma. This localization was confirmed by immunohistochemical measurements. With the microdialysis technique, it was demonstrated that local application of the KATP channel...... inhibitor glibenclamide reduced (P approximately 4.5 to 4.0 mM, whereas the concentration in the control leg remained constant. Glibenclamide had no effect on the interstitial K+ accumulation during knee-extensor exercise at a power output of 60 W. In contrast...

  5. Venous muscle pump function during pregnancy. Assessment by ambulatory strain-gauge plethysmography

    DEFF Research Database (Denmark)

    Struckmann, J R; Meiland, H; Bagi, P

    1990-01-01

    The venous muscle pump function was quantitatively assessed through pregnancy weeks 16, 30, 38 and 3 months (week 53) following delivery, in 24 pregnant women who completed a normal pregnancy. A statistically significant increase was found in the mean venous reflux (P less than 0.01), which...... was restored to initial values postpartum. Expelled calf volume remained stable throughout pregnancy but increased following delivery. Venous outflow from the legs was significantly reduced in the third trimester. Subjective symptoms of venous insufficiency increased through pregnancy, but, these symptoms had...... virtually disappeared post partum, corresponding to the muscle pump normalization. No statistical correlation was found between venous muscle pump values and changes in hormone concentrations of estradiol, estriol and progesterone. It is suggested that venous insufficiency development in pregnancy is caused...

  6. Effects of ageing on single muscle fibre contractile function following short-term immobilisation

    DEFF Research Database (Denmark)

    Hvid, Lars G; Ortenblad, Niels; Aagaard, Per

    2011-01-01

    Very little attention has been given to the combined effects of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile.......05), respectively. In conclusion, 2 weeks of lower limb immobilisation caused greater impairments in single muscle fibre force and specific force in MHC IIa than MHC I fibres independently of age. In contrast, immobilisation-induced changes in Ca(2+) sensitivity that were dependent on age and MHC isoform....... properties of single muscle fibres (n = 378) from vastus lateralis of nine young (24 ± 1 years) and eight old (67 ± 2 years) healthy men with comparable levels of physical activity. Prior to immobilisation, MHC IIa fibres produced higher maximum Ca(2+)-activated force (approx. 32%) and specific force (approx...

  7. Function and position determine relative proportions of different fiber types in limb muscles of the lizard Tropidurus psammonastes.

    Science.gov (United States)

    Pereira, Anieli G; Abdala, Virginia; Kohlsdorf, Tiana

    2015-02-01

    Skeletal muscles can be classified as flexors or extensors according to their function, and as dorsal or ventral according to their position. The latter classification evokes their embryological origin from muscle masses initially divided during limb development, and muscles sharing a given position do not necessarily perform the same function. Here, we compare the relative proportions of different fiber types among six limb muscles in the lizard Tropidurus psammonastes. Individual fibers were classified as slow oxidative (SO), fast glycolytic (FG) or fast oxidative-glycolytic (FOG) based on mitochondrial content; muscles were classified according to position and function. Mixed linear models considering one or both effects were compared using likelihood ratio tests. Variation in the proportion of FG and FOG fibers is mainly explained by function (flexor muscles have on average lower proportions of FG and higher proportions of FOG fibers), while variation in SO fibers is better explained by position (they are less abundant in ventral muscles than in those developed from a dorsal muscle mass). Our results clarify the roles of position and function in determining the relative proportions of the various muscle fibers and provide evidence that these factors may differentially affect distinct fiber types. Copyright © 2014. Published by Elsevier GmbH.

  8. Functional β-adrenoceptors are important for early muscle regeneration in mice through effects on myoblast proliferation and differentiation.

    Directory of Open Access Journals (Sweden)

    Jarrod E Church

    Full Text Available Muscles can be injured in different ways and the trauma and subsequent loss of function and physical capacity can impact significantly on the lives of patients through physical impairments and compromised quality of life. The relative success of muscle repair after injury will largely determine the extent of functional recovery. Unfortunately, regenerative processes are often slow and incomplete, and so developing novel strategies to enhance muscle regeneration is important. While the capacity to enhance muscle repair by stimulating β2-adrenoceptors (β-ARs using β2-AR agonists (β2-agonists has been demonstrated previously, the exact role β-ARs play in regulating the regenerative process remains unclear. To investigate β-AR-mediated signaling in muscle regeneration after myotoxic damage, we examined the regenerative capacity of tibialis anterior and extensor digitorum longus muscles from mice lacking either β1-AR (β1-KO and/or β2-ARs (β2-KO, testing the hypothesis that muscles from mice lacking the β2-AR would exhibit impaired functional regeneration after damage compared with muscles from β1-KO or β1/β2-AR null (β1/β2-KO KO mice. At 7 days post-injury, regenerating muscles from β1/β2-KO mice produced less force than those of controls but muscles from β1-KO or β2-KO mice did not exhibit any delay in functional restoration. Compared with controls, β1/β2-KO mice exhibited an enhanced inflammatory response to injury, which delayed early muscle regeneration, but an enhanced myoblast proliferation later during regeneration ensured a similar functional recovery (to controls by 14 days post-injury. This apparent redundancy in the β-AR signaling pathway was unexpected and may have important implications for manipulating β-AR signaling to improve the rate, extent and efficacy of muscle regeneration to enhance functional recovery after injury.

  9. Functional and morphological adaptations to aging in knee extensor muscles of physically active men.

    Science.gov (United States)

    Baroni, Bruno Manfredini; Geremia, Jeam Marcel; Rodrigues, Rodrigo; Borges, Marcelo Krás; Jinha, Azim; Herzog, Walter; Vaz, Marco Aurélio

    2013-10-01

    It is not known if a physically active lifestyle, without systematic training, is sufficient to combat age-related muscle and strength loss. Therefore, the purpose of this study was to evaluate if the maintenance of a physically active lifestyle prevents muscle impairments due to aging. To address this issue, we evaluated 33 healthy men with similar physical activity levels (IPAQ = 2) across a large range of ages. Functional (torque-angle and torque-velocity relations) and morphological (vastus lateralis muscle architecture) properties of the knee extensor muscles were assessed and compared between three age groups: young adults (30 ± 6 y), middle-aged subjects (50 ± 7 y) and elderly subjects (69 ± 5 y). Isometric peak torques were significantly lower (30% to 36%) in elderly group subjects compared with the young adults. Concentric peak torques were significantly lower in the middle aged (18% to 32%) and elderly group (40% to 53%) compared with the young adults. Vastus lateralis thickness and fascicles lengths were significantly smaller in the elderly group subjects (15.8 ± 3.9 mm; 99.1 ± 25.8 mm) compared with the young adults (19.8 ± 3.6 mm; 152.1 ± 42.0 mm). These findings suggest that a physically active lifestyle, without systematic training, is not sufficient to avoid loss of strength and muscle mass with aging.

  10. A 1D pulse wave propagation model of the hemodynamics of calf muscle pump function.

    Science.gov (United States)

    Keijsers, J M T; Leguy, C A D; Huberts, W; Narracott, A J; Rittweger, J; van de Vosse, F N

    2015-07-01

    The calf muscle pump is a mechanism which increases venous return and thereby compensates for the fluid shift towards the lower body during standing. During a muscle contraction, the embedded deep veins collapse and venous return increases. In the subsequent relaxation phase, muscle perfusion increases due to increased perfusion pressure, as the proximal venous valves temporarily reduce the distal venous pressure (shielding). The superficial and deep veins are connected via perforators, which contain valves allowing flow in the superficial-to-deep direction. The aim of this study is to investigate and quantify the physiological mechanisms of the calf muscle pump, including the effect of venous valves, hydrostatic pressure, and the superficial venous system. Using a one-dimensional pulse wave propagation model, a muscle contraction is simulated by increasing the extravascular pressure in the deep venous segments. The hemodynamics are studied in three different configurations: a single artery-vein configuration with and without valves and a more detailed configuration including a superficial vein. Proximal venous valves increase effective venous return by 53% by preventing reflux. Furthermore, the proximal valves shielding function increases perfusion following contraction. Finally, the superficial system aids in maintaining the perfusion during the contraction phase and reduces the refilling time by 37%. © 2015 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd.

  11. Standard characteristics of functional state of the rectal obturator muscles obtained from neurophysiological examination

    Directory of Open Access Journals (Sweden)

    O. Yu. Fomenko

    2017-01-01

    Full Text Available The objective was to evaluate standard neurophysiological characteristics of the external anal sphincter and pelvic floor muscles using electromyography interference pattern analysis.Materials and methods. Electromyography was performed in 33 volunteers without complaints of bowel incontinence or bowel evacuation disorders: 20 (60.6 % men (mean age 57.3 ± 9.4  years and 13 (39.4 % women (mean age 55.3 ± 12.8 years.  Intra-anal electrode registered cumulative values of contractile force  of sphincter ani externum: background and voluntary bioelectrical  activity (BEA. Integral values of mean and maximal BEA amplitude  for the rectal obturator muscles at rest, for voluntary contraction,  during straining, and with increased intra-abdominal pressure were calculated.Results. Standard values of BEA of the rectal obturator muscles were obtained. These values can be used for qualitative and quantitative evaluation of pelvic floor muscles function and in  additional multicenter studies aimed at development of a unified  algorithm of rectal obturator and pelvic floor muscles evaluation.

  12. Trabecular smooth muscle modulates the capacitor function of the penis. Studies on a rabbit model.

    Science.gov (United States)

    Saenz de Tejada, I; Moroukian, P; Tessier, J; Kim, J J; Goldstein, I; Frohrib, D

    1991-05-01

    We investigated the role of trabecular smooth muscle tone in regulation of intracavernosal pressure, venous outflow resistance, and penile capacitance. In an isolated rabbit whole penis model, corpora cavernosa were infused with either contracting (high K(+)-norepinephrine combination) or relaxing (no added Ca(2+)-papaverine combination) physiological salt solutions while intracavernosal pressure was recorded. An infusion pump regulated by an intracavernosal pressure feedback mechanism enabled the measurement of flow necessary to maintain intracavernosal pressures at 30, 60, 90, 120, and 150 mmHg under steady-state conditions (inflow = outflow). These experiments allowed resistance to outflow from corpora to be calculated when trabecular smooth muscle was either constricted or relaxed. Decay in intracavernosal pressure over time from various predetermined intracavernosal pressures (150, 120, 90, 60, and 30 mmHg) was studied under conditions of zero inflow following contraction or relaxation of trabecular smooth muscle. This permitted calculation of the time constant, which together with the outflow resistance, permitted the calculation of penile capacitance. When smooth muscle is relaxed, venous outflow resistance is high, constant, and independent of intracavernosal pressure. Furthermore, relaxation of smooth muscle allows expansion of corpora with accumulation of volume under pressure, enabling the penis to act as a capacitor. This capacitor function is limited in the presence of constant high outflow resistance by stiffness of the fibroelastic elements of penis, tunica, and fibroelastic frame, which exhibit nonlinear deflection trends. Analysis of these variables has led us to propose a model for penile erection.

  13. Sport-specific endurance plank test for evaluation of global core muscle function.

    Science.gov (United States)

    Tong, Tom K; Wu, Shing; Nie, Jinlei

    2014-02-01

    To examine the validity and reliability of a sports-specific endurance plank test for the evaluation of global core muscle function. Repeated-measures study. Laboratory environment. Twenty-eight male and eight female young athletes. Surface electromyography (sEMG) of selected trunk flexors and extensors, and an intervention of pre-fatigue core workout were applied for test validation. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and the measurement bias ratio */÷ ratio limits of agreement (LOA) were calculated to assess reliability and measurement error. Test validity was shown by the sEMG of selected core muscles, which indicated >50% increase in muscle activation during the test; and the definite discrimination of the ∼30% reduction in global core muscle endurance subsequent to a pre-fatigue core workout. For test-retest reliability, when the first attempt of three repeated trials was considered as familiarisation, the ICC was 0.99 (95% CI: 0.98-0.99), CV was 2.0 ± 1.56% and the measurement bias ratio */÷ ratio LOA was 0.99 */÷ 1.07. The findings suggest that the sport-specific endurance plank test is a valid, reliable and practical method for assessing global core muscle endurance in athletes given that at least one familiarisation trial takes place prior to measurement. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Serum levo-carnitine levels and skeletal muscle functions in type 2 diabetes mellitus in rodents

    International Nuclear Information System (INIS)

    Aleem, S.B.; Hussain, M.M.; Farooq, Y.

    2013-01-01

    Objective: To study serum levo-carnitine (l-carnitine) levels and isometric contraction, force frequency relationship and fatigue of rodent skeletal muscles in type 2 diabetes mellitus. Study Design: Randomized controlled trial. Place and Duration of Study: Physiology Department, Army Medical College, Rawalpindi, from January 2009 to January 2010. Methodology: Sixty Sprague-Dawley rats were randomly divided into two groups; group I (control), fed on normal diet ad libitum and Group II (diabetic), fed on high fat diet and administered streptozocin to induce type 2 diabetes mellitus (T2DM). At 21st day, plasma glucose and TG/HDL ratio were measured to confirm the development of T2DM in group II. At 28th day, blood was drawn by intracardiac puncture to estimate serum levo-carnitine levels. Contractile functions of skeletal muscles were assessed by using iWorx AHK/214 physiological data acquisition unit. Simple muscle twitches, maximum isometric twitch tension (MITT), time-to-peak twitch tension (TPTT) and time-to-relax to 50% of the peak twitch tension (1/2RT) of extensor digitorum muscles were recorded. Muscles were stimulated at higher frequencies to determine maximum fused tetanic tension (MFTT), maximum fused tetanic tension after fatigue protocol (TTFP) and recovery from fatigue (RF). Results: Serum levo-carnitine level decreased significantly in the diabetic group. Both groups had similar MITT, TPTT and 1/2RT but decline in MFTT, TTFP and RF was significant in the diabetic rats. Conclusion: T2DM adversely affected serum levo-carnitine levels and the contractile functions of rodent skeletal muscle at high frequency stimulation. (author)

  15. Muscle Lim Protein and myosin binding protein C form a complex regulating muscle differentiation.

    Science.gov (United States)

    Arvanitis, Demetrios A; Vafiadaki, Elizabeth; Papalouka, Vasiliki; Sanoudou, Despina

    2017-12-01

    Muscle Lim Protein (MLP) is a protein with multiple functional roles in striated muscle physiology and pathophysiology. Herein, we demonstrate that MLP directly binds to slow, fast, and cardiac myosin-binding protein C (MyBP-C) during myogenesis, as shown by yeast two-hybrid and a range of protein-protein interaction assays. The minimal interacting domains involve MLP inter-LIM and MyBP-C [C4]. The interaction is sensitive to cytosolic Ca 2+ concentrations changes and to MyBP-C phosphorylation by PKA or CaMKII. Confocal microscopy of differentiating myoblasts showed MLP and MyBP-C colocalization during myoblast differentiation. Suppression of the complex formation with recombinant MyBP-C [C4] peptide overexpression, inhibited myoblast differentiation by 65%. Suppression of both MLP and MyBP-C expression in myoblasts by siRNA revealed negative synergistic effects on differentiation. The MLP/MyBP-C complex modulates the actin activated myosin II ATPase activity in vitro, which could interfere with sarcomerogenesis and myofilaments assembly during differentiation. Our data demonstrate a critical role of the MLP/MyBP-C complex during early myoblast differentiation. Its absence in muscles with mutations or aberrant expression of MLP or MyBP-C could be directly implicated in the development of cardiac and skeletal myopathies. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Sub-cellular localisation of fukutin related protein in different cell lines and in the muscle of patients with MDC1C and LGMD2I

    DEFF Research Database (Denmark)

    Torelli, Silvia; Brown, Susan C; Brockington, Martin

    2005-01-01

    MDC1C and LGMD2I are two allelic forms of muscular dystrophies caused by mutations in the gene encoding for fukutin related protein (FKRP). FKRP encodes for a putative glycosyltransferase, the precise function of which is unknown. However, the marked reduction of alpha-dystroglycan glycosylation...... and in transverse sections of normal skeletal and cardiac muscle, endogenous FKRP surrounded the myonuclei. This localisation was unaffected in the skeletal muscle of patients with MDC1C and LGMD2I carrying various FKRP mutations. These observations imply a specific role for FKRP during striated muscle, neuronal...... and glial development and suggest that protein mis-localisation is not a common mechanism of disease in FKRP-related dystrophies....

  17. Vascular Function and Regulation of Blood Flow in Resting and Contracting Skeletal Muscle

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin

    importance. The present work provides new insight in to vasodilator interactions important for exercise hyperemia and sheds light on mechanisms important for vascular function and regulation of skeletal muscle blood flow in essential hypertension (high blood pressure) and aging and identifies mechanisms...... by which physical activity affects the function of the vascular network. Conclusion The vasodilators ATP and adenosine stimulate the nitric oxide and prostanoid systems in skeletal muscle. These vasodilator interactions may, at least in part, explain the central role of nitric oxide and prostanoids...... that no single compound can explain exercise hyperemia and indicates that any condition associated with reduced oxygen delivery needs to be investigated independently. Physical activity can attenuate or even counteract the effects of essential hypertension and aging on vascular function and exercise hyperemia....

  18. Genome-wide exploration of miRNA function in mammalian muscle cell differentiation.

    Science.gov (United States)

    Polesskaya, Anna; Degerny, Cindy; Pinna, Guillaume; Maury, Yves; Kratassiouk, Gueorgui; Mouly, Vincent; Morozova, Nadya; Kropp, Jeremie; Frandsen, Niels; Harel-Bellan, Annick

    2013-01-01

    MiRNAs impact on the control of cell fate by regulating gene expression at the post-transcriptional level. Here, using mammalian muscle differentiation as a model and a phenotypic loss-of-function screen, we explored the function of miRNAs at the genome-wide level. We found that the depletion of a high number of miRNAs (63) impacted on differentiation of human muscle precursors, underscoring the importance of this post-transcriptional mechanism of gene regulation. Interestingly, a comparison with miRNA expression profiles revealed that most of the hit miRNAs did not show any significant variations of expression during differentiation. These constitutively expressed miRNAs might be required for basic and/or essential cell function, or else might be regulated at the post-transcriptional level. MiRNA inhibition yielded a variety of phenotypes, reflecting the widespread miRNA involvement in differentiation. Using a functional screen (the STarS--Suppressor Target Screen--approach, i. e. concomitant knockdown of miRNAs and of candidate target proteins), we discovered miRNA protein targets that are previously uncharacterized controllers of muscle-cell terminal differentiation. Our results provide a strategy for functional annotation of the human miRnome.

  19. The improvement in respiratory function by inspiratory muscle training is due to structural muscle changes in patients with stroke: a randomized controlled pilot trial.

    Science.gov (United States)

    Cho, Ji-Eun; Lee, Hwang-Jae; Kim, Min-Kyu; Lee, Wan-Hee

    2018-01-01

    The changes effected by the inspiratory muscle training (IMT) on the structure of inspiratory muscles such as on the diaphragm, in patients with stroke, is unclear. To investigate the effect of IMT on inspiratory function, diaphragm thickness, walking endurance, and fatigue in patients with stroke. A total of 30 patients with stroke were randomized to either the experimental group or the control group. The experimental group (n = 15) underwent inspiratory muscle training with resistance adjusted to 30% of maximal inspiratory pressure, 90 breaths a day, 5 times a week for 6 weeks. Both groups received regular physical therapy for the same amount of time. The primary outcome measure was the diaphragm thickness ratio. The secondary outcomes were inspiratory function; maximal inspiratory pressure and inspiratory muscle endurance; and gait endurance and fatigue. There were significant differences between the two groups in the thickness ratio on the affected diaphragm thickness (medium effect size), maximal inspiratory pressure (medium effect size), and inspiratory muscle endurance (large effect size; Bonferroni correction p Inspiratory muscle training was effective in improving respiratory function and inducing structural changes, especially in the affected diaphragm.

  20. Correlation between mild hypoxaemia and limb skeletal muscle function in chronic obstructive pulmonary disease - pilot study.

    Science.gov (United States)

    Leite Rodrigues, Sérgio; Melo e Silva, César Augusto; Ferreira Amorim, César; Lima, Terezinha; Almeida Ribeiro, Fernanda; de Assis Viegas, Carlos Alberto

    2008-01-01

    Exercise capacity in COPD patients depends on the degree of airflow obstruction, the severity of the hypoxaemia and skeletal muscle function. Muscle atrophy and weakness are considered systemic consequences of COPD and are associated with reduced exercise capacity. To investigate the correlation between mild hypoxaemia and muscular strength, muscular fatigue and functional capacity in COPD patients. Ten patients enrolled on a PRP at the Hospital Universitário de Brasília - HUB were included in this study. Lung function was evaluated by spirometry and arterial blood gas analysis. Functional evaluation was made using the 6MWT and using isometric contraction of deltoid and quadriceps muscles. There were positive correlations between PaO2, quadriceps strength (r2 = 0.61 and p = 0.007) and PaO2 and the 6MWT (r2 = 0.96, p = 0.001). There were negative correlations between PaO2 and median frequency of quadriceps (r2 = -0.42 and p = 0.04). We observed significant correlation between quadriceps strength and the 6MWT (r2 = 0.67 and p = 0.001). There was negative correlation between median frequency of quadriceps and the 6MWT (r2 = -0.42 and p = 0.04). We did not observe any correlation between PaO2 and strength or median frequency of deltoid muscle. PaO2 has important correlations with muscular function variables. The main negative impact of mild hypoxaemia and precocious limb muscular disability on COPD patients is decreased functional capacity.

  1. Muscle power training in the institutionalized frail: a new approach to counteracting functional declines and very late-life disability.

    Science.gov (United States)

    Izquierdo, Mikel; Cadore, Eduardo Lusa

    2014-07-01

    Skeletal muscle power decreases earlier than muscle strength with advancing age and is more strongly associated with functional test performance than muscle strength in elderly populations. In addition, some studies have shown that resistance training designed to improve muscle power output (high speed of movement) enhances several functional outcomes in the healthy elderly. Therefore, muscle power has emerged as a factor that is also potentially associated with functional limitations in frail elderly adults. The purpose of this review was to provide recent evidence regarding the association between skeletal muscle power and functional capacity in physically frail individuals. Scielo, Science Citation Index, MEDLINE, Scopus, Sport Discus and ScienceDirect databases were searched from 1990 to 2014. Recently, it has been shown that functional capacity among frail elderly adults could be improved by performing resistance training at a high speed of movement with a loading stimulus that optimizes muscle power output. Routine multicomponent interventions that include muscle power training should be prescribed to institutionalized oldest old because such interventions improve the overall physical status of frail elderly individuals and prevent disability and other adverse outcomes. This result is especially important in frail subjects, who urgently need to improve their functional capacities to prevent adverse outcomes such as falls, hospitalizations, disability, or even death.

  2. Quadriceps muscle function after rehabilitation with cryotherapy in patients with anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Hart, Joseph M; Kuenze, Christopher M; Diduch, David R; Ingersoll, Christopher D

    2014-01-01

    Persistent muscle weakness after anterior cruciate ligament (ACL) reconstruction may be due to underlying activation failure and arthrogenic muscle inhibition (AMI). Knee-joint cryotherapy has been shown to improve quadriceps function transiently in those with AMI, thereby providing an opportunity to improve quadriceps muscle activation and strength in patients with a reconstructed ACL. To compare quadriceps muscle function in patients with a reconstructed ACL who completed a 2-week intervention including daily cryotherapy (ice bag), daily exercises, or both. Cross-sectional study. Laboratory. A total of 30 patients with reconstructed ACLs who were at least 6 months post-index surgery and had measurable quadriceps AMI. The patients attended 4 supervised visits over a 2-week period. They were randomly assigned to receive 20 minutes of knee-joint cryotherapy, 1 hour of therapeutic rehabilitation exercises, or cryotherapy followed by exercises. We measured quadriceps Hoffmann reflex, normalized maximal voluntary isometric contraction torque, central activation ratio using the superimposed-burst technique, and patient-reported outcomes before and after the intervention period. After the 2-week intervention period, patients who performed rehabilitation exercises immediately after cryotherapy had higher normalized maximal voluntary isometric contraction torques (P = .002, Cohen d effect size = 1.4) compared with those who received cryotherapy alone (P = .16, d = 0.58) or performed exercise alone (P = .16, d = 0.30). After ACL reconstruction, patients with AMI who performed rehabilitation exercises immediately after cryotherapy experienced greater strength gains than those who performed cryotherapy or exercises alone.

  3. Redox state and mitochondrial respiratory chain function in skeletal muscle of LGMD2A patients.

    Directory of Open Access Journals (Sweden)

    Mats I Nilsson

    Full Text Available Calpain-3 deficiency causes oxidative and nitrosative stress-induced damage in skeletal muscle of LGMD2A patients, but mitochondrial respiratory chain function and anti-oxidant levels have not been systematically assessed in this clinical population previously.We identified 14 patients with phenotypes consistent with LGMD2A and performed CAPN3 gene sequencing, CAPN3 expression/autolysis measurements, and in silico predictions of pathogenicity. Oxidative damage, anti-oxidant capacity, and mitochondrial enzyme activities were determined in a subset of muscle biopsies.Twenty-one disease-causing variants were detected along the entire CAPN3 gene, five of which were novel (c.338 T>C, c.500 T>C, c.1525-1 G>T, c.2115+4 T>G, c.2366 T>A. Protein- and mRNA-based tests confirmed in silico predictions and the clinical diagnosis in 75% of patients. Reductions in antioxidant defense mechanisms (SOD-1 and NRF-2, but not SOD-2, coupled with increased lipid peroxidation and protein ubiquitination, were observed in calpain-3 deficient muscle, indicating a redox imbalance primarily affecting non-mitochondrial compartments. Although ATP synthase levels were significantly lower in LGMD2A patients, citrate synthase, cytochrome c oxidase, and complex I+III activities were not different from controls.Despite significant oxidative damage and redox imbalance in cytosolic/myofibrillar compartments, mitochondrial respiratory chain function is largely maintained in skeletal muscle of LGMD2A patients.

  4. Cross-sectional retrospective study of muscle function in patients with glycogen storage disease type III.

    Science.gov (United States)

    Decostre, Valérie; Laforêt, Pascal; Nadaj-Pakleza, Aleksandra; De Antonio, Marie; Leveugle, Sylvain; Ollivier, Gwenn; Canal, Aurélie; Kachetel, Kahina; Petit, François; Eymard, Bruno; Behin, Anthony; Wahbi, Karim; Labrune, Philippe; Hogrel, Jean-Yves

    2016-09-01

    Glycogen storage disease type III is an inherited metabolic disorder characterized by liver and muscle impairment. This study aimed to identify promising muscle function measures for future studies on natural disease progression and therapeutic trials. The age-effect on the manual muscle testing (MMT), the hand-held dynamometry (HHD), the motor function measure (MFM) and the Purdue pegboard test was evaluated by regression analysis in a cross-sectional retrospective single site study. In patients aged between 13 and 56 years old, the Purdue pegboard test and dynamometry of key pinch and knee extension strength were age-sensitive with annual losses of 1.49, 1.10 and 0.70% of the predicted values (%pred), respectively. The MFM score and handgrip strength were also age-sensitive but only in patients older than 29 and 37 years old with annual losses of 1.42 and 1.84%pred, respectively. Muscle strength assessed by MMT and elbow extension measured by HHD demonstrated an annual loss of less than 0.50%pred and are thus unlikely to be promising outcome measures for future clinical trials. In conclusion, our results identified age-sensitive outcomes from retrospective data and may serve for future longitudinal studies in which an estimation of the minimal number of subjects is provided. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effects of functional resistance training on muscle strength and musculoskeletal discomfort

    Directory of Open Access Journals (Sweden)

    Bruna Montechieze Cassemiro

    Full Text Available Abstract Introduction: Functional resistance training (FRT is becoming increasingly popular to improve physical fitness of practitioners, however, yet there are gaps in knowledge about effectiveness of FRT in relation conventional resistance training (CRT in several ambits, as musculoskeletal complaints. Objective: Compare the effect of FRT and CRT in the musculoskeletal discomfort and magnitude of gain in muscle strength in healthy women. Methods: 52 women was divided into three groups, FRT (n = 15; 22 ± 2.35 years: functional resistance training; CRT (n = 14; 22.5 ± 1.78 years: conventional resistance training and CG (n = 13; 20.6 ± 1.10 years: no type of intervention. The training was periodized in 30 sessions over 12 weeks with 3 sessions per week. For the muscle strength variable used the 1RM test and for the musculoskeletal discomfort variable, the Nordic Musculoskeletal Questionnaire (NMQ. Regarding the statistical analysis, all results took into consideration a 5% level of significance. Results: Considerable gain in muscle strength was observed for all exercises in both training groups. In addition, there was a tendency in CRT to relate a more musculoskeletal discomfort; presented 27.3% more complaints compared FRT in the MNQ. Conclusion: The FRT was as effective as the CRT for improving muscle strength, furthermore, there was a tendency for FRT to cause less musculoskeletal discomfort.

  6. Implantation of In Vitro Tissue Engineered Muscle Repair Constructs and Bladder Acellular Matrices Partially Restore In Vivo Skeletal Muscle Function in a Rat Model of Volumetric Muscle Loss Injury

    Science.gov (United States)

    2014-01-01

    functional analysis Torque production of the left anterior crural muscles (primarily due to the contraction of the TA and EDL mus- cles) was measured in...responders based on the following criteria. A TA muscle transplanted with a TEMR construct that recovered a peak torque value greater than 1 standard deviation...Functionally, removal of the EDL and EHL muscles resulted in a - 29.4% – 7.4% loss of peak torque from 4 to 12 weeks postablation when normalized to preinjury

  7. Impaired skeletal muscle mitochondrial function in morbidly obese patients is normalized one year after bariatric surgery.

    Science.gov (United States)

    Vijgen, Guy H E J; Bouvy, Nicole D; Hoeks, Joris; Wijers, Sander; Schrauwen, Patrick; van Marken Lichtenbelt, Wouter D

    2013-01-01

    Obesity and type 2 diabetes are associated with impaired skeletal muscle mitochondrial metabolism. As an intrinsic characteristic of an individual, skeletal muscle mitochondrial dysfunction could be a risk factor for weight gain and obesity-associated co-morbidities, such as type 2 diabetes. On the other hand, impaired skeletal muscle metabolism could be a consequence of obesity. We hypothesize that marked weight loss after bariatric surgery recovers skeletal muscle mitochondrial function. Skeletal muscle mitochondrial function as assessed by high-resolution respirometry was measured in 8 morbidly obese patients (body mass index [BMI], 41.3±4.7 kg/m(2); body fat, 48.3%±5.2%) before and 1 year after bariatric surgery (mean weight loss: 35.0±8.6 kg). The results were compared with a lean (BMI 22.8±1.1 kg/m(2); body fat, 15.6%±4.7%) and obese (BMI 33.5±4.2 kg/m(2); body fat, 34.1%±6.3%) control group. Before surgery, adenosine diphosphate (ADP)-stimulated (state 3) respiration on glutamate/succinate was decreased compared with lean patients (9.5±2.4 versus 15.6±4.4 O2 flux/mtDNA; Psurgery, mitochondrial function was comparable to that of lean controls (after weight loss, 12.3±5.5; lean, 15.6±4.4 O2 flux/mtDNA). In addition, we observed an increased state 3 respiration on a lipid substrate after weight loss (10.0±3.2 versus 14.0±6.6 O2 flux/mtDNA; Pweight loss. Copyright © 2013 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  8. Does phototherapy enhance skeletal muscle contractile function and postexercise recovery? A systematic review.

    Science.gov (United States)

    Borsa, Paul A; Larkin, Kelly A; True, Jerry M

    2013-01-01

    Recently, researchers have shown that phototherapy administered to skeletal muscle immediately before resistance exercise can enhance contractile function, prevent exercise-induced cell damage, and improve postexercise recovery of strength and function. To critically evaluate original research addressing the ability of phototherapeutic devices, such as lasers and light-emitting diodes (LEDs), to enhance skeletal muscle contractile function, reduce exercise-induced muscle fatigue, and facilitate postexercise recovery. We searched the electronic databases PubMed, SPORTDiscus, Web of Science, Scopus, and Rehabilitation & Physical Medicine without date limitations for the following key words: laser therapy, phototherapy, fatigue, exercise, circulation, microcirculation, and photobiomodulation. Eligible studies had to be original research published in English as full papers, involve human participants, and receive a minimum score of 7 out of 10 on the Physiotherapy Evidence Database (PEDro) scale. Data of interest included elapsed time to fatigue, total number of repetitions to fatigue, total work performed, maximal voluntary isometric contraction (strength), electromyographic activity, and postexercise biomarker levels. We recorded the PEDro scores, beam characteristics, and treatment variables and calculated the therapeutic outcomes and effect sizes for the data sets. In total, 12 randomized controlled trials met the inclusion criteria. However, we excluded data from 2 studies, leaving 32 data sets from 10 studies. Twenty-four of the 32 data sets contained differences between active phototherapy and sham (placebo-control) treatment conditions for the various outcome measures. Exposing skeletal muscle to single-diode and multidiode laser or multidiode LED therapy was shown to positively affect physical performance by delaying the onset of fatigue, reducing the fatigue response, improving postexercise recovery, and protecting cells from exercise-induced damage

  9. Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

    Directory of Open Access Journals (Sweden)

    Morgan Lanzarin

    2016-02-01

    Full Text Available BACKGROUND: Intermittent claudication (IC is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance. OBJECTIVE: This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication. METHOD: The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6 and 16 healthy controls (mean age: 67 years, SD=5, which were allocated into two groups: intermittent claudication group (ICG and control group (CG. Postural control was assessed using the displacement and velocity of the center of pressure (COP during the sensory organization test (SOT and the motor control test (MCT. Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences. RESULTS: The ICG presented greater displacement (p =0.027 and speed (p =0.033 of the COP in the anteroposterior direction (COPap during the MCT, as well as longer latency (p =0.004. There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG. CONCLUSION: Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects.

  10. Effects of Testosterone Supplementation for 3 Years on Muscle Performance and Physical Function in Older Men

    Science.gov (United States)

    Basaria, Shehzad; Traustadottir, Tinna; Harman, S. Mitchell; Pencina, Karol; Li, Zhuoying; Travison, Thomas G.; Miciek, Renee; Tsitouras, Panayiotis; Hally, Kathleen; Huang, Grace; Bhasin, Shalender

    2017-01-01

    Context: Findings of studies of testosterone’s effects on muscle strength and physical function in older men have been inconsistent; its effects on muscle power and fatigability have not been studied. Objective: To determine the effects of testosterone administration for 3 years in older men on muscle strength, power, fatigability, and physical function. Design, Setting, and Participants: This was a double-blind, placebo-controlled, randomized trial of healthy men ≥60 years old with total testosterone levels of 100 to 400 ng/dL or free testosterone levels testosterone or placebo gel daily for 3 years. Outcome Measures: Loaded and unloaded stair-climbing power, muscle strength, power, and fatigability in leg press and chest press exercises, and lean mass at baseline, 6, 18, and 36 months. Results: The groups were similar at baseline. Testosterone administration for 3 years was associated with significantly greater performance in unloaded and loaded stair-climbing power than placebo (mean estimated between-group difference, 10.7 W [95% confidence interval (CI), −4.0 to 25.5], P = 0.026; and 22.4 W [95% CI, 4.6 to 40.3], P = 0.027), respectively. Changes in chest-press strength (estimated mean difference, 16.3 N; 95% CI, 5.5 to 27.1; P testosterone than in those randomized to placebo. Lean body mass significantly increased more in the testosterone group. Conclusion: Compared with placebo, testosterone replacement in older men for 3 years was associated with modest but significantly greater improvements in stair-climbing power, muscle mass, and power. Clinical meaningfulness of these treatment effects and their impact on disability in older adults with functional limitations remains to be studied. PMID:27754805

  11. Functional capacity, pulmonary and respiratory muscle strength in individuals undergoing hemodialysis

    Directory of Open Access Journals (Sweden)

    Simone Regina Posser

    Full Text Available Abstract Introduction: Individuals with chronic kidney disease (CKD undergoing hemodialysis (HD present low cardiorespiratory fitness and functional capacity. Metabolic changes, due to the disease, can result in a variety of pathophysiological conditions that favor the development of respiratory muscle weakness. However, very little is known about the performance of the respiratory muscles and the influence of HD on them. Aim: To evaluate and correlate pulmonary function, functional capacity and respiratory muscle strength in patients with CKD undergoing HD. Methods: Cross-sectional study comprising 23 patients with CKD, that met the following inclusion criteria: patients of both genders, who perform HD three times a week for a minimum period of three months. Respiratory muscle strength was evaluated using a respiratory pressure meter, lung function through spirometry and functional capacity through the 6-minute walk test (6MWT before the HD session. Results: All patients were male and mean age was 50.2 ± 15.8 years. The median duration of HD was 3 (1.5 to 6.0 years. The mean values obtained in comparison to those predicted were MIP% 36.0 ± 13.6, MEP% 49.5 ± 15.8, FVC% 93.8 ± 21.1, FEV1% 93.7 ± 21.1, FVC/VEF1% 104.1 ± 10.3, and 6MWT% 66.33 ± 20.53. A statistically significant positive correlation was observed between the 6MWT and MIP (r = .63, p =.001 and MEP (r = .67, p < .001, between the MIP and MEP (r =.79, p < .001 and between the FEV1 and FVC (r = .91, p < .001. Conclusion: Patients with CKD undergoing HD present changes in respiratory muscle strength, with the predicted values decreasing for age and gender, as well as the distance covered in the 6MWT, although, with normal spirometric values. Functional capacity was dependent on respiratory muscle strength, as well as the values of MIP and MEP, and the values of FVC and FEV1.

  12. Power Grid Protection of the Muscle Mitochondrial Reticulum

    Directory of Open Access Journals (Sweden)

    Brian Glancy

    2017-04-01

    Full Text Available Summary: Mitochondrial network connectivity enables rapid communication and distribution of potential energy throughout the cell. However, this connectivity puts the energy conversion system at risk, because damaged elements could jeopardize the entire network. Here, we demonstrate the mechanisms for mitochondrial network protection in heart and skeletal muscle (SKM. We find that the cardiac mitochondrial reticulum is segmented into subnetworks comprising many mitochondria linked through abundant contact sites at highly specific intermitochondrial junctions (IMJs. In both cardiac and SKM subnetworks, a rapid electrical and physical separation of malfunctioning mitochondria occurs, consistent with detachment of IMJs and retraction of elongated mitochondria into condensed structures. Regional mitochondrial subnetworks limit the cellular impact of local dysfunction while the dynamic disconnection of damaged mitochondria allows the remaining mitochondria to resume normal function within seconds. Thus, mitochondrial network security is comprised of both proactive and reactive mechanisms in striated muscle cells. : Network connectivity allows information sharing and distribution but also enables propagation of localized dysfunction. Glancy et al. demonstrate the existence of both proactive and reactive network protection mechanisms designed to minimize the spread of dysfunction throughout the coupled mitochondrial networks in heart and skeletal muscle cells. Keywords: energy distribution, muscle energetics, oxidative phosphorylation, 3D electron microscopy, mitochondrial retraction, mitochondrial dynamics

  13. Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease.

    Science.gov (United States)

    Mittal, Ravinder K

    2016-09-01

    Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed contract and relax together in almost perfect synchrony during ascending contraction and descending relaxation of the peristaltic reflex, respectively. Studies in patients with various types of esophageal motor disorders reveal temporal disassociation between the circular and longitudinal muscle layers. We suggest that the discoordination between the two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain. Certain pathologies may selectively target one and not the other muscle layer, e.g., in eosinophilic esophagitis there is a selective dysfunction of the longitudinal muscle layer. In achalasia esophagus, swallows are accompanied by the strong contraction of the longitudinal muscle without circular muscle contraction. The possibility that the discoordination between two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain are discussed. The purpose of this review is to summarize the regulation and dysregulation of peristalsis by the coordinated and discoordinated function of circular and longitudinal muscle layers in health and diseased states.

  14. Comparison of gluteus medius muscle activity during functional tasks in individuals with and without osteoarthritis of the hip joint.

    Science.gov (United States)

    Dwyer, Maureen K; Stafford, Kelly; Mattacola, Carl G; Uhl, Timothy L; Giordani, Mauro

    2013-08-01

    Neuromuscular alterations have been reported for patients with osteoarthritis of the hip joint; however, the underlying cause associated with altered gluteus medius muscle function has not been examined. This study assessed electromyographic amplitudes of the gluteus medius muscles during function in patients with unilateral end-stage osteoarthritis of the hip joint compared to controls. Patients with unilateral end-stage hip joint osteoarthritis (n=13) and asymptomatic control participants (n=17) participated. Average root-mean squared muscle amplitudes represented as a percent of maximum voluntary isometric contraction for both the involved and uninvolved limb gluteus medius muscles were analyzed during step up, step down, and gait. The association between muscle activation and impact forces during stepping tasks was assessed. Patients with hip osteoarthritis exhibited increased gluteus medius muscle electromyographic amplitudes bilaterally during stair ascent, stair descent, and gait compared to controls, regardless of which limb they led. Involved limb muscle activity was inversely related to impact force during step down onto the ipsilateral limb. Patients with hip osteoarthritis demonstrated increased gluteus medius muscle activation levels during stepping tasks and gait when compared to controls. The increased activation is most likely a compensatory response to muscle weakness. Therefore, application of strengthening exercises which target the gluteal muscles should assist in neuromuscular control and result in improved strength for patients with hip joint osteoarthritis. © 2013. Published by Elsevier Ltd on behalf of American Society of Biomechanics. All rights reserved.

  15. Dietary Exercise as a Novel Strategy for the Prevention and Treatment of Metabolic Syndrome: Effects on Skeletal Muscle Function

    OpenAIRE

    Aoi, Wataru; Naito, Yuji; Yoshikawa, Toshikazu

    2011-01-01

    A sedentary lifestyle can cause metabolic syndrome to develop. Metabolic syndrome is associated with metabolic function in the skeletal muscle, a major consumer of nutrients. Dietary exercise, along with an adequate diet, is reported to be one of the major preventive therapies for metabolic syndrome; exercise improves the metabolic capacity of muscles and prevents the loss of muscle mass. Epidemiological studies have shown that physical activity reduces the risk of various common diseases suc...

  16. Intrinsic muscle strength and voluntary activation of both lower limbs and functional performance after stroke.

    Science.gov (United States)

    Horstman, Astrid M; Beltman, Marijke J; Gerrits, Karin H; Koppe, Peter; Janssen, Thomas W; Elich, Peter; de Haan, Arnold

    2008-07-01

    The objective of this study was to assess the nature of muscle weakness in both legs after stroke compared with able-bodied control individuals and to examine whether there is a relationship between the degree of muscle weakness and coactivation of knee extensors and flexors as well as voluntary activation capacity of knee extensors of both paretic and non-paretic legs and indices of functional performance. Maximal voluntary isometric torques of knee extensors (MVCe) and flexors (MVCf) were determined in 14 patients (bilaterally) and 12 able-bodied controls. Simultaneous measurements were made of torque and surface EMG from agonist and antagonist muscles. Coactivation was calculated. Supramaximal triplets were evoked with electrical stimulation to estimate maximal torque capacity and degree of voluntary activation of knee extensors. MVCs, activation and coactivation parameters were correlated to scores of seven functional performance tests. MVCe, MVCf and voluntary activation were lower in paretic lower limb (PL) compared with both non-paretic lower limb (NL) and control. Besides, all these parameters of NL were also lower than control. Electrically evoked torque capacity of knee extensors of PL was about 60% of both NL and control, which were not significantly different from each other. Strong significant correlations between strength, as well as voluntary activation, and functional performance were found. Coactivation did not correlate well with functional performance. Thus, whereas for NL activation failure can explain weakness, for PL both activation failure and reduced intrinsic torque capacity are responsible for the severe weakness. Activation capacity and muscle strength correlated strongly to functional performance, while coactivation did not.

  17. Falls, muscle strength, and functional abilities in community-dwelling elderly women

    Directory of Open Access Journals (Sweden)

    Viviane Santos Borges

    Full Text Available Abstract Introduction: Falls are among the most common and serious problems facing elderly women. Falling is associated with increased mortality, morbidity, reduced functioning, loss of independence and hospitalization. Objective: The aim of this study was to investigate the association among fear of falling, muscle strength, and functional abilities in community-dwelling elderly women. Methods: Forty-nine elderly women (70.57 ± 5.59 years participated in this study. Records of falls, self-efficacy associated with falls (FES-I Brazil, functional abilities (the Timed Up and Down Stairs test [TUDS] and the Timed Up and Go test [TUG], lower limb muscle strength (knee extensors and ankle plantar flexors, and hand grip strength were investigated as variables of interest. Descriptive statistics, the one-way ANOVA, and linear regression tests were used to analyze the association between fear of falling and falls with other variables (α = 0.05. Results: Elderly women who presented records of falls within the last year had lesser strength of knee extensors and plantar flexors (p ≤. 05. Those who had low self-efficacy associated with falls presented lower strength of knee extensors (p ≤. 01. Variables associated with functional abilities (r = 0.70 and lower limb strength (r = 0.53 showed a positive correlation (p ≤. 01. Conclusion: The concern with the fear of falling and falls may be negative effects caused by lower limb muscle weakness.

  18. A review of the biomechanical and functional changes in the shoulder following transfer of the latissimus dorsi muscles.

    Science.gov (United States)

    Spear, Scott L; Hess, Christopher L

    2005-06-01

    The latissimus dorsi muscle is among the most commonly used muscle flaps because it has broad versatility and is generally believed to result in minimal donor-site morbidity. However, the normal physiology of the shoulder girdle depends on the function of this muscle. Therefore, we have undertaken this review of the literature to examine the issue of biomechanical and functional changes of the shoulder that occur with transfer of the latissimus dorsi muscle and to determine whether these changes result in deficits in normal function. A review of the literature pertaining to all aspects of the latissimus muscle and shoulder function following muscle transfer was conducted. The latissimus muscle functions in extension, adduction, and internal and external rotation. After the transfer of the muscle there are deficits in extension and adduction. These deficits result in a faster rate of fatigue during activities in which the arms are extended over the head, such as ladder climbing and swimming. In addition, there is no decrease in range of shoulder motion.

  19. Lumbar muscle structure and function in chronic versus recurrent low back pain: a cross-sectional study.

    Science.gov (United States)

    Goubert, Dorien; De Pauw, Robby; Meeus, Mira; Willems, Tine; Cagnie, Barbara; Schouppe, Stijn; Van Oosterwijck, Jessica; Dhondt, Evy; Danneels, Lieven

    2017-09-01

    Heterogeneity exists within the low back pain (LBP) population. Some patients recover after every pain episode, whereas others suffer daily from LBP complaints. Until now, studies rarely make a distinction between recurrent low back pain (RLBP) and chronic low back pain (CLBP), although both are characterized by a different clinical picture. Clinical experiences also indicate that heterogeneity exists within the CLBP population. Muscle degeneration, like atrophy, fat infiltration, alterations in muscle fiber type, and altered muscle activity, compromises proper biomechanics and motion of the spinal units in LBP patients. The amount of alterations in muscle structure and muscle function of the paraspinal muscles might be related to the recurrence or chronicity of LBP. The aim of this experimental study is to evaluate differences in muscle structure (cross-sectional area and lean muscle fat index) and muscle activity of the multifidus (MF) and erector spinae (ES) during trunk extension, in patients with RLBP, non-continuous CLBP, and continuous CLBP. This cross-sectional study took place in the university hospital of Ghent, Belgium. Muscle structure characteristics and muscle activity were assessed by magnetic resonance imaging (MRI). Fifty-five adults with non-specific LBP (24 RLBP in remission, 15 non-continuous CLBP, 16 continuous CLBP) participated in this study. Total cross-sectional area, muscle cross-sectional area, fat cross-sectional area, lean muscle fat index, T2-rest and T2-shift were assessed. A T1-weighted Dixon MRI scan was used to evaluate spinal muscle cross-sectional area and fat infiltration in the lumbar MF and ES. Muscle functional MRI was used to evaluate the muscle activity of the lumbar MF and ES during a lumbar extension exercise. Before and after the exercise, a pain assessment was performed. This study was supported by grants from the Special Research Fund of Ghent University (DEF12/AOP/022) without potential conflict of interest

  20. The gaseous plasmonic response of a one-dimensional photonic crystal composed of striated plasma layers

    Science.gov (United States)

    Wang, B.; Righetti, F.; Cappelli, M. A.

    2018-03-01

    We present simulations of the response of a one-dimensional striated plasma slab to incident electromagnetic waves that span regions both above and below the plasma frequency, ωp. Photonic bandgap modes are present throughout these regions, and volume and surface plasmon modes facilitate the response below ωp, where the dielectric constant, ɛp application of these structures as ultra-narrow tunable microwave transmission filters.