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Sample records for suum muscle electronic

  1. Monepantel is a non-competitive antagonist of nicotinic acetylcholine receptors from Ascaris suum and Oesophagostomum dentatum

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    Melanie Abongwa

    2018-04-01

    Full Text Available Zolvix® is a recently introduced anthelmintic drench containing monepantel as the active ingredient. Monepantel is a positive allosteric modulator of DEG-3/DES-2 type nicotinic acetylcholine receptors (nAChRs in several nematode species. The drug has been reported to produce hypercontraction of Caenorhabditis elegans and Haemonchus contortus somatic muscle. We investigated the effects of monepantel on nAChRs from Ascaris suum and Oesophagostomum dentatum heterologously expressed in Xenopus laevis oocytes. Using two-electrode voltage-clamp electrophysiology, we studied the effects of monepantel on a nicotine preferring homomeric nAChR subtype from A. suum comprising of ACR-16; a pyrantel/tribendimidine preferring heteromeric subtype from O. dentatum comprising UNC-29, UNC-38 and UNC-63 subunits; and a levamisole preferring subtype (O. dentatum comprising UNC-29, UNC-38, UNC-63 and ACR-8 subunits. For each subtype tested, monepantel applied in isolation produced no measurable currents thereby ruling out an agonist action. When monepantel was continuously applied, it reduced the amplitude of acetylcholine induced currents in a concentration-dependent manner. In all three subtypes, monepantel acted as a non-competitive antagonist on the expressed receptors. ACR-16 from A. suum was particularly sensitive to monepantel inhibition (IC50 values: 1.6 ± 3.1 nM and 0.2 ± 2.3 μM. We also investigated the effects of monepantel on muscle flaps isolated from adult A. suum. The drug did not significantly increase baseline tension when applied on its own. As with acetylcholine induced currents in the heterologously expressed receptors, contractions induced by acetylcholine were antagonized by monepantel. Further investigation revealed that the inhibition was a mixture of competitive and non-competitive antagonism. Our findings suggest that monepantel is active on multiple nAChR subtypes. Keywords: Monepantel, Zolvix®, Nicotinic acetylcholine

  2. The In Vitro Effect of Ivermectin on the Activity of Trehalose Synthesis Pathway Enzymes and Their mRNA Expression in the Muscle of Adult Female Ascaris suum (Nematoda)

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    Dmitryjuk, Małgorzata; Łopieńska-Biernat, Elżbieta; Zaobidna, Ewa Anna

    2014-01-01

    The in vitro effect of ivermectin lethal dose on the activity of trehalose-6-phosphate synthase (TPS) and phosphatase (TPP) and the expression of their mRNA (tps1, tps2, and tpp genes) in the muscle of adult female Ascaris suum was investigated. The presence of ivermectin in the medium caused a decrease in TPS and TPP activities during the experiment compared with the start and control groups. The exception was the group of worms grown for 8 hours in a IVM solution, in which there was a littl...

  3. Population dynamics of Ascaris suum in trickle-infected pigs.

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    Nejsum, Peter; Thamsborg, Stig M; Petersen, Heidi H; Kringel, Helene; Fredholm, Merete; Roepstorff, Allan

    2009-10-01

    The population dynamics of Ascaris suum was studied by long-term exposure of pigs to infective eggs. The pigs were experimentally inoculated with 25 A. suum eggs/kg/day, and 7, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 postinoculation (PI), respectively. Despite the fact that the pigs were continuously reinfected, dramatic reductions in numbers of liver lesions (white spots) and migrating lung larvae were observed as a function of time. However, even at the end of the study, a few larvae were able to complete migration, but these larvae seemed unable to mature in the small intestine. Thus, the adult worm population seemed to consist of worms from the first part of the exposure period. The noticeable decrease in number of white spots suggests that the level of exposure is not reflected in the number of white spots in the late phase of a continuous infection. The serum levels of A. suum L3-specific IgG1 and IgA were significantly elevated by week 4 PI, after which the antibody levels declined. The population dynamics and parasite regulating mechanisms are discussed for A. suum in pigs as well as for the closely related species A. lumbricoides in humans.

  4. Interaction between Ascaris suum and Pasteurella multocida in the lungs of mice

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    Tjørnehøj, Kirsten; Eriksen, Lizzie; Aalbaek, B

    1992-01-01

    In an experiment including 8 groups of 15 mice, the effect of migrating Ascaris suum larvae in the lungs on the establishment and pathogenicity of aerosol exposure to Pasteurella multocida was investigated. Following aerosol exposure to P. multocida, mice with migrating A. suum in their lungs...

  5. Impact of Ascaris suum in livestock

    DEFF Research Database (Denmark)

    Thamsborg, Stig Milan; Nejsum, Peter; Mejer, Helena

    2013-01-01

    The roundworm Ascaris suum is a highly prevalent intestinal parasite of pigs worldwide, and the infection may have low to moderate pathogenic effects on health and productivity. Besides these direct effects, there may be indirect effects on enhanced susceptibility or pathogenicity to bacterial or...

  6. Effects of Some Pesticides on Development of Ascaris suum Eggs

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    Yu, Yong-Man; Kim, Jin-Won; Na, Won-Seok; Youn, Young-Nam; Choi, In-Wook

    2014-01-01

    To evaluate the effects of pesticides to parasite eggs, Ascaris suum eggs were incubated with 5 different pesticides (1:1,500-1:2,000 dilutions of 2% emamectin benzoate, 5% spinetoram, 5% indoxacarb, 1% deltamethrin, and 5% flufenoxuron; all v/v) at 20℃ for 6 weeks, and microscopically evaluated the egg survival and development on a weekly basis. The survival rate of A. suum eggs incubated in normal saline (control eggs) was 90±3% at 6 weeks. However, the survival rates of eggs treated with pesticides were 75-85% at this time, thus significantly lower than the control value. Larval development in control eggs commenced at 3 weeks, and 73±3% of eggs had internal larvae at 6 weeks. Larvae were evident in pesticide-treated eggs at 3-4 weeks, and the proportions of eggs carrying larvae at 6 weeks (36±3%-54±3%) were significantly lower than that of the control group. Thus, pesticides tested at levels similar to those used in agricultural practices exhibited low-level ovicidal activity and delayed embryogenesis of A. suum eggs, although some differences were evident among the tested pesticides. PMID:24623893

  7. Effect of fenbendazole in water on pigs infected with Ascaris suum in finishing pigs under field conditions.

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    Lassen, Brian; Oliviero, Claudio; Orro, Toomas; Jukola, Elias; Laurila, Tapio; Haimi-Hakala, Minna; Heinonen, Mari

    2017-04-15

    The husbandry of pigs for meat production is a constantly developing industry. Most studies on the effects of Ascaris suum infection in pigs and its prevention with anthelmintics are over a decade old. We examined the effect of 2.5mg fenbendazole per kg bodyweight administered in drinking water for two consecutive days on A. suum infection 1 and 6 weeks after pigs arrived to fattening units. We hypothesised that the treatment would reduce the presence of A. suum-infections, improve the average daily weight gain of pigs, reduce the percentage of liver rejections in pens by 50% and increase the lean meat percentage at slaughter by 1%. The study included a placebo group (427 pigs) and a treatment group (420 pigs) spanning four different farms previously reporting ≥15% liver rejection. The treatment was given for 2 consecutive days 1 and 6 weeks after the pigs arrived to the fattening unit. Faecal samples were collected during weeks 1, 6 and 12 from all pigs and examined for A. suum eggs. Blood was collected during weeks 1 and 12 from a subgroup of the pigs and examined for anti-A. suum antibodies and clinical blood parameters. Data on liver rejection and lean meat percentage were collected post-mortem. The proportion of Ascaris seropositive pigs changed from 8.6% to 22.2% and 20.3% to 16.3% in the placebo and treatment group respectively. Fenbendazole reduced the presence of A. suum eggs in faeces the percentage of liver rejections by 69.8%. The treatment did not affect daily weight gain or lean meat percentage. Pigs with A. suum eggs in faeces at week 6 had a lower average daily weight gain of 61.8g/day compared with pigs without parasite eggs. Fenbendazole treatment may be a useful option for farms struggling with persistent A. suum problems and demonstrate a beneficial effect on the weight gain of the animals shedding eggs in faeces and result in fewer condemned livers at slaughter. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Direct anthelmintic effects of condensed tannins from diverse plant sources against Ascaris suum.

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    Andrew R Williams

    Full Text Available Ascaris suum is one of the most prevalent nematode parasites in pigs and causes significant economic losses, and also serves as a good model for A. lumbricoides, the large roundworm of humans that is ubiquitous in developing countries and causes malnutrition, stunted growth and compromises immunity to other pathogens. New treatment options for Ascaris infections are urgently needed, to reduce reliance on the limited number of synthetic anthelmintic drugs. In areas where Ascaris infections are common, ethno-pharmacological practices such as treatment with natural plant extracts are still widely employed. However, scientific validation of these practices and identification of the active compounds are lacking, although observed effects are often ascribed to plant secondary metabolites such as tannins. Here, we extracted, purified and characterised a wide range of condensed tannins from diverse plant sources and investigated anthelmintic effects against A. suum in vitro. We show that condensed tannins can have potent, direct anthelmintic effects against A. suum, as evidenced by reduced migratory ability of newly hatched third-stage larvae and reduced motility and survival of fourth-stage larvae recovered from pigs. Transmission electron microscopy showed that CT caused significant damage to the cuticle and digestive tissues of the larvae. Furthermore, we provide evidence that the strength of the anthelmintic effect is related to the polymer size of the tannin molecule. Moreover, the identity of the monomeric structural units of tannin polymers may also have an influence as gallocatechin and epigallocatechin monomers exerted significant anthelmintic activity whereas catechin and epicatechin monomers did not. Therefore, our results clearly document direct anthelmintic effects of condensed tannins against Ascaris and encourage further in vivo investigation to determine optimal strategies for the use of these plant compounds for the prevention and

  9. The nicotinic acetylcholine receptors of the parasitic nematode Ascaris suum: formation of two distinct drug targets by varying the relative expression levels of two subunits.

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    Sally M Williamson

    2009-07-01

    Full Text Available Parasitic nematodes are of medical and veterinary importance, adversely affecting human health and animal welfare. Ascaris suum is a gastrointestinal parasite of pigs; in addition to its veterinary significance it is a good model of the human parasite Ascaris lumbricoides, estimated to infect approximately 1.4 billion people globally. Anthelmintic drugs are essential to control nematode parasites, and nicotinic acetylcholine receptors (nAChRs on nerve and muscle are the targets of cholinergic anthelmintics such as levamisole and pyrantel. Previous genetic analyses of nematode nAChRs have been confined to Caenorhabditis elegans, which is phylogenetically distinct from Ascaris spp. and many other important parasites. Here we report the cloning and expression of two nAChR subunit cDNAs from A. suum. The subunits are very similar in sequence to C. elegans UNC-29 and UNC-38, are expressed on muscle cells and can be expressed robustly in Xenopus oocytes to form acetylcholine-, nicotine-, levamisole- and pyrantel-sensitive channels. We also demonstrate that changing the stoichiometry of the receptor by injecting different ratios of the subunit cRNAs can reproduce two of the three pharmacological subtypes of nAChR present in A. suum muscle cells. When the ratio was 5:1 (Asu-unc-38ratioAsu-unc-29, nicotine was a full agonist and levamisole was a partial agonist, and oocytes responded to oxantel, but not pyrantel. At the reverse ratio (1:5 Asu-unc-38ratioAsu-unc-29, levamisole was a full agonist and nicotine was a partial agonist, and the oocytes responded to pyrantel, but not oxantel. These results represent the first in vitro expression of any parasitic nicotinic receptor and show that their properties are substantially different from those of C. elegans. The results also show that changing the expression level of a single receptor subunit dramatically altered the efficacy of some anthelmintic drugs. In vitro expression of these subunits may permit the

  10. Effect of fenbendazole in water on pigs infected with Ascaris suum in finishing pigs under field conditions

    DEFF Research Database (Denmark)

    Lassen, Brian; Oliviero, Claudio; Orro, Toomas

    2017-01-01

    The husbandry of pigs for meat production is a constantly developing industry. Most studies on the effects of Ascaris suum infection in pigs and its prevention with anthelmintics are over a decade old. We examined the effect of 2.5 mg fenbendazole per kg bodyweight administered in drinking water...... post-mortem. The proportion of Ascaris seropositive pigs changed from 8.6% to 22.2% and 20.3% to 16.3% in the placebo and treatment group respectively. Fenbendazole reduced the presence of A. suum eggs in faeces the percentage of liver rejections by 69.8%. The treatment did not affect daily weight gain...... or lean meat percentage. Pigs with A. suum eggs in faeces at week 6 had a lower average daily weight gain of 61.8 g/day compared with pigs without parasite eggs. Fenbendazole treatment may be a useful option for farms struggling with persistent A. suum problems and demonstrate a beneficial effect...

  11. Potensi Serbuk Daun Kelor (Moringa oleifera Sebagai Anthelmintik Terhadap Infeksi Ascaris suum dan Feed Supplement pada Babi

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    Muhammad Ulqiya Syukron

    2015-06-01

    Full Text Available Pig ascariasis is an intestinal parasitic disease caused by Ascaris suum. The economic losses in pig ascariasis are caused by a bad feed conversion ratio (FCR and rejection of some organs after animal slaughtering. An anthelmintic utilization and farm management improvement are the common prevention action, however, recently the utilization of herbs as an athelmintic has been developed, one of them is Moringa oleifera leaves. Moringa oleifera leaves are also a potential for a sources of animal food because of their high nutrients. This intervention research aimed to examine the anthelmintic effect of Moringa oleifera leaves and its potency as feed supplement. Experimental design used was ccompletely randomized design split time (CRD Split Time with six treatments namely Moringa oleifera 5% and an infection of infective larvae of A. suum (1, Moringa oleifera 5% (2, positive control (3, Moringa oleifera 10% (4, Moringa oleifera 10% and infection of infective larvae of A. suum (5, and no treatment as negative control (6. Each treatment was imposed on four female landrace piglets aged 8 weeks and weighed around 11 kg. The results showed that Moringa oleifera 5% and 10% of the feed could inhibit the egg production of A.suum and had a significant effect (P<0.05 on weight gain of piglets. It can be concluded that Moringa oleifera leave have an anthelmintic effect to prevent the infection of A. suum and a potential for a feed supplement on pigs.

  12. Flavanol-Rich Cocoa Powder Interacts with Lactobacillus rhamnossus LGG to Alter the Antibody Response to Infection with the Parasitic Nematode Ascaris suum.

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    Jang, Saebyeol; Lakshman, Sukla; Beshah, Ethiopia; Xie, Yue; Molokin, Aleksey; Vinyard, Bryan T; Urban, Joseph F; Davis, Cindy D; Solano-Aguilar, Gloria I

    2017-10-12

    Consumption of the probiotic bacteria Lactobacillus rhamnosus LGG and flavanol-rich cocoa have purported immune modulating effects. This study compared the host response to infection with Ascaris suum in three-month-old pigs fed a standard growth diet supplemented with a vehicle control: LGG, cocoa powder (CP) or LGG + CP. Pigs were inoculated with infective A . suum eggs during Week 5 of dietary treatment and euthanized 17 days later. Lactobacillus abundance was increased in pigs fed LGG or LGG + CP. Specific anti- A . suum IgG2 antibodies were decreased ( p < 0.05) in LGG + CP-fed pigs compared to pigs fed CP alone. Pigs fed LGG had significantly reduced expression ( p < 0.05) of Eosinophil peroxidase ( EPX) , Interleukin 13 ( IL-13) , Eotaxin 3 ( CCL26) , Toll-like receptor 2 ( TLR2 ), TLR4, and TLR9 and Interleukin-1Beta ( IL1B ) in the tracheal-bronchial lymph node (TBLN) independent of CP treatment. These results suggested that feeding LGG significantly reduced the localized prototypical Th2-related markers of infection with A . suum in the TBLN. Although feeding CP does not appear to affect the A . suum- induced Th2-associated cytokine response, feeding LGG + CP reduced anti- A . suum antibodies and delayed intestinal expulsion of parasitic larvae from the intestine.

  13. Flavanol-Rich Cocoa Powder Interacts with Lactobacillus rhamnossus LGG to Alter the Antibody Response to Infection with the Parasitic Nematode Ascaris suum

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    Saebyeol Jang

    2017-10-01

    Full Text Available Consumption of the probiotic bacteria Lactobacillus rhamnosus LGG and flavanol-rich cocoa have purported immune modulating effects. This study compared the host response to infection with Ascaris suum in three-month-old pigs fed a standard growth diet supplemented with a vehicle control: LGG, cocoa powder (CP or LGG + CP. Pigs were inoculated with infective A. suum eggs during Week 5 of dietary treatment and euthanized 17 days later. Lactobacillus abundance was increased in pigs fed LGG or LGG + CP. Specific anti-A. suum IgG2 antibodies were decreased (p < 0.05 in LGG + CP-fed pigs compared to pigs fed CP alone. Pigs fed LGG had significantly reduced expression (p < 0.05 of Eosinophil peroxidase (EPX, Interleukin 13 (IL-13, Eotaxin 3 (CCL26, Toll-like receptor 2 (TLR2, TLR4, and TLR9 and Interleukin-1Beta (IL1B in the tracheal-bronchial lymph node (TBLN independent of CP treatment. These results suggested that feeding LGG significantly reduced the localized prototypical Th2-related markers of infection with A. suum in the TBLN. Although feeding CP does not appear to affect the A. suum-induced Th2-associated cytokine response, feeding LGG + CP reduced anti-A. suum antibodies and delayed intestinal expulsion of parasitic larvae from the intestine.

  14. Vermisidal dan Ovisidal Ekstrak Daun Pepaya Terhadap Cacing Ascaris suum Secara In Vitro

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    Agung Mourizd Adventus Bili Bora

    2014-05-01

    Full Text Available Tujuan penelitian ini untuk mengetahui vermisidal dan ovisidal dari ekstrak daun pepaya terhadap cacing Ascaris suum. Menggunakan  Rancangan  Acak  Lengkap (RAL, dengan perlakuan beberapa konsentrasi ekstrak daun pepaya 1,5%, 3%, 4,5% dan 6%; kontrol negatif menggunakan NaCl fisiologis dan kontrol positif menggunakan Albendazole 0,12%. Dilakukan uji vermisidal dan uji  ovisidal, uji ovisidal dibagi  menjadi  dua  uji,  yaitu kontak langsung dan kontak tidak  langsung. Untuk uji vermisidal data dianalisis dengan Analisis Probit untuk mengetahui LC100 (Lethal concentration dan LT100 (Lethal  time, sedangkan  untuk  uji  ovisidal  data dianalisis dengan Sidik Ragam dan  jika terdapat perbedaan, dilanjutkan dengan uji jarak berganda Duncan. Hasil  penelitian  vermisidal  didapatkan  LC100 ekstrak  daun  pepaya adalah  3,362%  dan  LT100 39,822  jam.  Untuk  uji  ovisidal  kontak  langsung  dan kontak tidak langsung didapatkan ekstrak daun pepaya berpengaruh sangat nyata (P<0,01 terhadap daya berembrio telur A. suum. Dari hasil penelitian ini disimpulkan bahwa ekstrak daun pepaya efektif sebagai vermisidal dan ovisidal terhadap cacing A. suum secara in-vitro.

  15. A polyphenol-enriched diet and Ascaris suum infection modulate mucosal immune responses and gut microbiota composition in pigs.

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    Andrew R Williams

    Full Text Available Polyphenols are a class of bioactive plant secondary metabolites that are thought to have beneficial effects on gut health, such as modulation of mucosal immune and inflammatory responses and regulation of parasite burdens. Here, we examined the interactions between a polyphenol-rich diet supplement and infection with the enteric nematode Ascaris suum in pigs. Pigs were fed either a basal diet or the same diet supplemented with grape pomace (GP, an industrial by-product rich in polyphenols such as oligomeric proanthocyanidins. Half of the animals in each group were then inoculated with A. suum for 14 days to assess parasite establishment, acquisition of local and systemic immune responses and effects on the gut microbiome. Despite in vitro anthelmintic activity of GP-extracts, numbers of parasite larvae in the intestine were not altered by GP-supplementation. However, the bioactive diet significantly increased numbers of eosinophils induced by A. suum infection in the duodenum, jejunum and ileum, and modulated gene expression in the jejunal mucosa of infected pigs. Both GP-supplementation and A. suum infection induced significant and apparently similar changes in the composition of the prokaryotic gut microbiota, and both also decreased concentrations of isobutyric and isovaleric acid (branched-chain short chain fatty acids in the colon. Our results demonstrate that while a polyphenol-enriched diet in pigs may not directly influence A. suum establishment, it significantly modulates the subsequent host response to helminth infection. Our results suggest an influence of diet on immune function which may potentially be exploited to enhance immunity to helminths.

  16. Immunizing pigs with Ascaris suum hemoglobin increases the inflammatory response in the liver but fails to induce a protective immunity

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    To determine whether purified Ascaris suum hemoglobin (AsHb) is a suitable vaccine candidate for the control of Ascaris infections, pigs were 30 vaccinated with AsHb in combination with QuilA adjuvant and challenged with A. suum eggs. The number of liver lesions and worms in the intestine was assess...

  17. A genetic marker allele conferring resistance to Ascaris suum in pigs

    DEFF Research Database (Denmark)

    Skallerup, Per; Thamsborg, Stig M.; Jørgensen, Claus B.

    2013-01-01

    Mapping of quantitative trait loci (QTLs) has helped dissecting the genetics underlying the variation in resistance to helminth infections. In pigs, two single nucleotide polymorphisms (SNP TXNIP and SNP ARNT), both on chromosome 4, have been reported to be associated with Ascaris suum worm burden...

  18. Yeast-expressed recombinant As16 protects mice against Ascaris suum infection through induction of a Th2-skewed immune response.

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    Junfei Wei

    2017-07-01

    Full Text Available Ascariasis remains the most common helminth infection in humans. As an alternative or complementary approach to global deworming, a pan-anthelminthic vaccine is under development targeting Ascaris, hookworm, and Trichuris infections. As16 and As14 have previously been described as two genetically related proteins from Ascaris suum that induced protective immunity in mice when formulated with cholera toxin B subunit (CTB as an adjuvant, but the exact protective mechanism was not well understood.As16 and As14 were highly expressed as soluble recombinant proteins (rAs16 and rAs14 in Pichia pastoris. The yeast-expressed rAs16 was highly recognized by immune sera from mice infected with A. suum eggs and elicited 99.6% protection against A. suum re-infection. Mice immunized with rAs16 formulated with ISA720 displayed significant larva reduction (36.7% and stunted larval development against A. suum eggs challenge. The protective immunity was associated with a predominant Th2-type response characterized by high titers of serological IgG1 (IgG1/IgG2a > 2000 and high levels of IL-4 and IL-5 produced by restimulated splenocytes. A similar level of protection was observed in mice immunized with rAs16 formulated with alum (Alhydrogel, known to induce mainly a Th2-type immune response, whereas mice immunized with rAs16 formulated with MPLA or AddaVax, both known to induce a Th1-type biased response, were not significantly protected against A. suum infection. The rAs14 protein was not recognized by A. suum infected mouse sera and mice immunized with rAs14 formulated with ISA720 did not show significant protection against challenge infection, possibly due to the protein's inaccessibility to the host immune system or a Th1-type response was induced which would counter a protective Th2-type response.Yeast-expressed rAs16 formulated with ISA720 or alum induced significant protection in mice against A. suum egg challenge that associates with a Th2-skewed immune

  19. Ascaris Suum Infection Downregulates Inflammatory Pathways in the Pig Intestine In Vivo and in Human Dendritic Cells In Vitro

    DEFF Research Database (Denmark)

    Midttun, Helene L. E.; Acevedo, Nathalie; Skallerup, Per

    2018-01-01

    similar transcriptional pathways in human dendritic cells (DCs) in vitro. DCs exposed to ABF secreted minimal amounts of cytokines and had impaired production of cyclooxygengase-2, altered glucose metabolism, and reduced capacity to induce interferon-gamma production in T cells. Our in vivo and in vitro......Ascaris suum is a helminth parasite of pigs closely related to its human counterpart, A. lumbricoides, which infects almost 1 billion people. Ascaris is thought to modulate host immune and inflammatory responses, which may drive immune hyporesponsiveness during chronic infections. Using...... transcriptomic analysis, we show here that pigs with a chronic A. suum infection have a substantial suppression of inflammatory pathways in the intestinal mucosa, with a broad downregulation of genes encoding cytokines and antigen-processing and costimulatory molecules. A. suum body fluid (ABF) suppressed...

  20. Ascaris suum infection negatively affects the response to a Mycoplasma hyopneumoniae vaccination and subsequent challenge infection in pigs

    DEFF Research Database (Denmark)

    Steenhard, Nina R.; Jungersen, Gregers; Kokotovic, Branko

    2009-01-01

    Since their first introduction more than a century ago, vaccines have become one of the most cost-effective tools to prevent and manage infectious diseases in human and animal populations. It is vital to understand the possible mechanisms that may impair optimal vaccine efficacy. The hypothesis...... posed in this study was that a concurrent Ascaris suum infection of pigs vaccinated with a Mycoplasma hyopneumoniae (Mh)vaccine would modulate the protectiveimmuneresponse to a subsequent challenge infection. Four groups of pigs were either (1) untreated (group C), (2) vaccinated againstMh 3 weeks after...... the start of the study (group V), (3) given a trickle infection with A. suum throughout the study (group A), or (4) given a trickle infection with A. suum and vaccinated against Mh (group AV). All pigs were subsequently inoculated with live Mh bacteria 4 weeks after the Mh vaccination and necropsied after...

  1. Environmental contamination and transmission of Ascaris suum in Danish organic pig farms

    DEFF Research Database (Denmark)

    Katakam, Kiran K.; Thamsborg, Stig M.; Dalsgaard, Anders

    2016-01-01

    Background: Although Ascaris suum is the most common pig nematode, the on-farm transmission dynamics are not well described. Methods: We performed a 1-year field study on five organic pig farms, mapping egg contamination levels in pens and pasture soil as well as faecal egg counts in starter pigs...... % in starters, finishers, dry and lactating sows, respectively. For starters and finishers, the prevalence varied with season increasing towards the end of the year when 83-96 % of finishing pigs from each farm had fresh liver white spots. Farrowing pastures were contaminated with a mean of 78-171 larvated eggs....../kg dry soil depending on farm, while pastures for starter pigs contained 290-5397 larvated eggs/kg dry soil. The concentration of eggs in soil was highest in the autumn. Indoors, all pen areas were contaminated with A. suum eggs at comparable levels for shallow and deep litter. Overall there were 106...

  2. Development and survival of Ascaris suum eggs in deep litter of pigs

    DEFF Research Database (Denmark)

    Katakam, Kiran Kumar; Thamsborg, Stig Milan; Kyvsgaard, Niels Christian

    2014-01-01

    SUMMARY Indoor transmission of Ascaris suum partly depends on the physico-chemical conditions in bedding material. Temperature, pH, aqueous ammonia, moisture, occurrence and development of A. suum eggs were therefore compared in different areas (resting, intermediate and latrine) of two deep litter......·7 °C) levels. The area contained few eggs (50 eggs g-1 DM) of which 17% were viable, and though only 4% were larvated and 0·7% appeared infective, it was more than in the other areas. Intermediate areas had moderate moisture (43%) and high temperature (43·6 °C) levels. There were many eggs (523 eggs g......-1 DM), but overall viability was very low (5%) and few eggs were larvated (0·004%) or even infective (0·002%). Latrines typically had high moisture (79%) and moderate temperature (30 °C) levels. The concentration of eggs was very high (1444 egg g-1 DM) and though 32% were viable, none had developed...

  3. Cross-Reactions between Toxocara canis and Ascaris suum in the diagnosis of visceral larva migrans by western blotting technique

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    NUNES Cáris Maroni

    1997-01-01

    Full Text Available Visceral larva migrans (VLM is a clinical syndrome caused by infection of man by Toxocara spp, the common roundworm of dogs and cats. Tissue migration of larval stages causes illness specially in children. Because larvae are difficult to detect in tissues, diagnosis is mostly based on serology. After the introduction of the enzyme-linked immunosorbent assay (ELISA using the larval excretory-secretory antigen of T. canis (TES, the diagnosis specificity was greatly improved although cross-reactivity with other helminths are still being reported. In Brazil, diagnosis is routinely made after absorption of serum samples with Ascaris suum antigens, a nematode antigenicaly related with Ascaris lumbricoides which is a common intestinal nematode of children. In order to identify T. canis antigens that cross react to A. suum antigens we analyzed TES antigen by SDS-PAGE and Western blotting techniques. When we used serum samples from patients suspected of VLM and positive result by ELISA as well as a reference serum sample numerous bands were seen (molecular weight of 210-200 kDa, 116-97 kDa, 55-50 kDa and 35-29 kDa. Among these there is at least one band with molecular weight around 55-66 kDa that seem to be responsible for the cross-reactivity between T. canis e A. suum once it disappears when previous absorption of serum samples with A. suum antigens is performed

  4. A novel C-type lectin identified by EST analysis in tissue migratory larvae of Ascaris suum.

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    Yoshida, Ayako; Nagayasu, Eiji; Horii, Yoichiro; Maruyama, Haruhiko

    2012-04-01

    C-type lectins (CTLs) are a group of proteins which bind to carbohydrate epitopes in the presence of Ca(2+), which have been described in a wide range of species. In this study, a cDNA sequence coding a putative CTL has been identified from the cDNA library constructed from the pig round worm Ascaris suum lung L3 (LL3) larvae, which was designated as A. suum C-type lectin-1 (As-CTL-1). The 510 nucleotide open reading frame of As-CTL-1 cDNA encoded the predicted 169 amino acid protein including a putative signal peptide of 23 residues and C-type lectin/C-type lectin-like domain (CLECT) at residue 26 to 167. As-CTL-1 was most similar to Toxocara canis C-type lectin-1 and 4 (Tc-CTL-1 and 4), and highly homologous to namatode CTLs and mammalian CTLs as well, such as human C-type lectin domain family 4 member G (CLECG4). In addition, As-CTL-1 was strongly expressed in tissue migrating LL3 and the L4 larvae, which were developmental larvae stages within the mammalian host. These results suggest that A. suum larvae might utilize As-CTL-1 to avoid pathogen recognition mechanisms in mammalian hosts due to it is similarity to host immune cell receptors.

  5. Changes in the viability of the eggs of Ascaris suum under the influence of flavourings and source materials approved for use in and on foods

    Directory of Open Access Journals (Sweden)

    A. A. Boyko

    2017-05-01

    Full Text Available One of the most common parasitic diseases of pigs globally is ascariasis. It is caused by the nematode Ascaris suum Goeze, 1782 (Nematoda, Ascaridata, which parasitises the small intestine of pigs in its mature form and the respiratory system at the larval stage. This helminthiasis causes immense damage to swine-rearing. Control of the ascariasis pathogen in the host’s organism and in the environment is essential for the health of the animals and successful swine-rearing. The results of studying the effect of flavourings and source materials approved for use in and on foods – cinnamaldehyde (0656 Codex Alimentarius, benzoic acid (Е210 Codex Alimentarius and methylparaben (Е218 Codex Alimentarius , on the viability of invasive eggs of A. suum are useful for determining the minimum concentration of solution of these substances for use against eggs of A. suum (10 g/l. The lowest efficiency against invasive eggs of A. suum was obtained for methylparaben (LD50 = 3850 ± 2130 mg/l, the highest was obtained with cinnamaldehyde (LD50 = 2437 ± 864 mg/l, and benzoic acid (LD50 = 1240 ± 680 mg/l.

  6. Studies on the survival of Ascaris suum eggs under laboratory and simulated field conditions

    NARCIS (Netherlands)

    Gaasenbeek, C.P.H.; Borgsteede, F.H.M.

    1998-01-01

    A series of four experiments was carried out to study the survival of Ascaris suum eggs: in a pig slurry unit on a farm, in the laboratory under anaerobic conditions and different relative humidities (rH), and under simulated field conditions. Survival of eggs in the pig slurry unit was 20% after

  7. Direct anthelmintic effects of condensed tannins from diverse plant sources against Ascaris suum

    DEFF Research Database (Denmark)

    Williams, Andrew Richard; Fryganas, Christos; Ramsay, Aina

    2014-01-01

    Ascaris suum is one of the most prevalent nematode parasites in pigs and causes significant economic losses, and also serves as a good model for A. lumbricoides, the large roundworm of humans that is ubiquitous in developing countries and causes malnutrition, stunted growth and compromises immuni...

  8. Functional study of a genetic marker allele associated with resistance to Ascaris suum in pigs

    DEFF Research Database (Denmark)

    Skallerup, Per; Thamsborg, Stig M.; Jørgensen, Claus B.

    2014-01-01

    trickle-infected with A. suum until necropsy at week 8 post first infection (PI), to test the hypothesis that pigs with the AA genotype would have higher levels of resistance than pigs of the AB genotype. We used different indicators of resistance (worm burden, faecal egg counts, number of liver white...

  9. A polyphenol-enriched diet and Ascaris suum infection modulate mucosal immune responses and gut microbiota composition in pigs

    DEFF Research Database (Denmark)

    Williams, Andrew R.; Krych, Lukasz; Ahmad, Hajar Fauzan

    2017-01-01

    . suum for 14 days to assess parasite establishment, acquisition of local and systemic immune responses and effects on the gut microbiome. Despite in vitro anthelmintic activity of GP-extracts, numbers of parasite larvae in the intestine were not altered by GP-supplementation. However, the bioactive diet......Polyphenols are a class of bioactive plant secondary metabolites that are thought to have beneficial effects on gut health, such as modulation of mucosal immune and inflammatory responses and regulation of parasite burdens. Here, we examined the interactions between a polyphenol-rich diet...... supplement and infection with the enteric nematode Ascaris suum in pigs. Pigs were fed either a basal diet or the same diet supplemented with grape pomace (GP), an industrial by-product rich in polyphenols such as oligomeric proanthocyanidins. Half of the animals in each group were then inoculated with A...

  10. Assessing the zoonotic potential of Ascaris suum and Trichuris suis

    DEFF Research Database (Denmark)

    Nejsum, Peter; Betson, M.; Bendall, R. P.

    2012-01-01

    The two geohelminths, Ascaris lumbricoides and Trichuris trichiura, infect more than a billion people worldwide but are only reported sporadically in the developed part of the world. In contrast, the closely related species A. suum and T. suis in pigs have a truly global distribution, with infect...... and pig host, with special focus on recent evidence concerning the zoonotic potential of these parasites, and identify some open questions for future research....

  11. Effect of post-treatment conditions on the inactivation of helminth eggs (Ascaris suum) after the composting process.

    Science.gov (United States)

    Darimani, Hamidatu S; Ito, Ryusei; Maiga, Ynoussa; Sou, Mariam; Funamizu, Naoyuki; Maiga, Amadou H

    2016-01-01

    Safe and appropriate disposal of human waste is a basic requirement for sanitation and protection of public health. For proper sanitation and nutrient recovery, it is necessary to ensure effective treatment methods to complete pathogen destruction in excreta prior to reuse. Composting toilets convert faeces to a reusable resource such as fertilizer or humus for organic agriculture. A composting toilet for rural Burkina Faso was created by modifying a commercial model available in Japan to improve hygiene and increase food production. The toilet has shown to result in a degraded final product, but its effectiveness for pathogen destruction was unclear due to low temperatures generated from the toilet. This study aimed to sanitize compost withdrawn from the composting toilet for food production by setting post-treatment conditions. The inactivation kinetics of Ascaris suum eggs, selected as an indicator for helminth eggs, was determined during post-treatment at different temperatures (30°C, 40°C, 50°C and 60°C) with varying moisture contents (MC) (50%, 60% and 70%). The treatment of compost in a possible additional post-treatment after the composting process was tried in the laboratory test. Inactivation of A. suum eggs was fast with greater than two log reductions achieved within 2 h for temperature 50°C and 50% MC and greater than three log reductions for temperature 60°C and 50% MC within 3 h. Statistical analysis showed the significant impact of temperature and moisture on the inactivation rates of A. suum eggs. The post-treatment can efficiently increase helminth eggs destruction prior to reuse.

  12. Ascaris suum infection negatively affects the response to a Mycoplasma hyopneumoniae vaccination and subsequent challenge infection in pigs

    Science.gov (United States)

    It is vital to understand the possible mechanisms that may impair optimal vaccine efficacy. The hypothesis posed in this study was that a concurrent Ascaris suum infection of pigs vaccinated with a Mycoplasma hyopneumoniae (Mh) vaccine would modulate the protective immune response to a subsequent ch...

  13. An in vitro larval migration assay for assessing anthelmintic activity of different drug classes against Ascaris suum

    DEFF Research Database (Denmark)

    Zhao, Jianguo; Williams, Andrew R; Hansen, Tina Vicky Alstrup

    2017-01-01

    and agar gel larval migration assay to test the effect of benzimidazole and tetrahydropyrimidin/imidazothiazole anthelmintics against nine isolates of A. suum collected from locations in China and Denmark. Drugs tested were thiabendazole, fenbendazole, mebendazole, levamisole, and pyrantel. The percentages...

  14. In vitro evaluation of the ovistatic and ovicidal effect of the cosmopolitan filamentous fungi isolated from soil on Ascaris suum eggs.

    Science.gov (United States)

    Blaszkowska, Joanna; Kurnatowski, Piotr; Wojcik, Anna; Goralska, Katarzyna; Szwabe, Katarzyna

    2014-01-31

    The ovicidal activity of seven fungal strains: Acremonium alabamense, Alternaria chlamydospora, Cladosporium herbarum, Fusarium solani, Paecilomyces variotii, Paecilomyces viridis and Penicillium verruculosum isolated from urban soil samples from Poland was determined in vitro. The fungal mycelium was co-cultured with Ascaris suum eggs on plates with 2% water-agar for 28 days. Eggs exposed and unexposed (control) to fungal mycelium were observed weekly by light microscopy and the percentage of malformed eggs were determined. The eggs were classified according to following parameters: type 1 - biochemical and physiological effect without morphological damage to the eggshell; type 2 - lytic effect with morphological alteration of the eggshell and embryo; type 3 - lytic effect with morphological alteration of eggshell and embryo with hyphal penetration and internal egg colonization. All examined species of fungi extended embryogenesis, but the retardation of embryonic development was varied and depended on the species. A. alabamense, A. chlamydospora and P. verruculosum exhibited very high inhibitory activity on A. suum egg development. The fungus-exposed eggs revealed morphological alternations in all stages of embryogenesis. Isolates of F. solani, P. variotii and P. viridis showed hyphal penetration and internal colonization of A. suum eggs (type 3 effect). No appressoria were produced and simple hyphal penetrations were most commonly observed. A. alabamense and P. verruculosum demonstrated morphological destruction, with eggshell destruction. The remaining fungi showed type 1 effect. The results demonstrated that examined strains of F. solani, P. variotii and P. viridis may be considered to be potential limiting factors of parasitic geohelminth populations. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Molecular evidence for sustained transmission of zoonotic Ascaris suum among zoo chimpanzees (Pan troglodytes)

    DEFF Research Database (Denmark)

    Nejsum, Peter; Bertelsen, Mads Frost; Betson, Martha

    Chimpanzees in the Copenhagen Zoo frequently excrete ascarid worms onto the cage floor inspite of a regular anthelmintic treatment program. Previously it had been shown that the source of the infections was of pig origin. However, it was unknown whether the recurrence of the infection was due...... analysis of the cox1 gene (‘barcoding') on expelled worms followed by cluster analysis revealed that the chimpanzees are infected with pig A. suum which now, in spite of control efforts, has stabilized into a permanent transmission cycle in the Zoo's chimpanzee troop...

  16. Microfluidic platform for electrophysiological recordings from host-stage hookworm and Ascaris suum larvae: A new tool for anthelmintic research

    Directory of Open Access Journals (Sweden)

    Janis C. Weeks

    2016-12-01

    Full Text Available The screening of candidate compounds and natural products for anthelmintic activity is important for discovering new drugs against human and animal parasites. We previously validated in Caenorhabditis elegans a microfluidic device (‘chip’ that records non-invasively the tiny electrophysiological signals generated by rhythmic contraction (pumping of the worm's pharynx. These electropharyngeograms (EPGs are recorded simultaneously from multiple worms per chip, providing a medium-throughput readout of muscular and neural activity that is especially useful for compounds targeting neurotransmitter receptors and ion channels. Microfluidic technologies have transformed C. elegans research and the goal of the current study was to validate hookworm and Ascaris suum host-stage larvae in the microfluidic EPG platform. Ancylostoma ceylanicum and A. caninum infective L3s (iL3s that had been activated in vitro generally produced erratic EPG activity under the conditions tested. In contrast, A. ceylanicum L4s recovered from hamsters exhibited robust, sustained EPG activity, consisting of three waveforms: (1 conventional pumps as seen in other nematodes; (2 rapid voltage deflections, associated with irregular contractions of the esophagus and openings of the esophogeal-intestinal valve (termed a ‘flutter’; and (3 hybrid waveforms, which we classified as pumps. For data analysis, pumps and flutters were combined and termed EPG ‘events.’ EPG waveform identification and analysis were performed semi-automatically using custom-designed software. The neuromodulator serotonin (5-hydroxytryptamine; 5HT increased EPG event frequency in A. ceylanicum L4s at an optimal concentration of 0.5 mM. The anthelmintic drug ivermectin (IVM inhibited EPG activity in a concentration-dependent manner. EPGs from A. suum L3s recovered from pig lungs exhibited robust pharyngeal pumping in 1 mM 5HT, which was inhibited by IVM. These experiments validate the use of A

  17. Experimental destruction of Ascarid ova in sewage sludge by accelerated electron irradiation

    International Nuclear Information System (INIS)

    Horak, Petr

    1994-01-01

    Aerobically-treated sewage sludge containing eggs of the nematode Ascaris suum was processed using accelerated electrons. After 8 weeks of incubation the morphological and developmental status of eggs was determined. Inhibition of development and the destruction of nematode embryos within eggs were observed at doses over 1.1 kGy. (author)

  18. Parasite-specific IL-4 responses in Ascaris suum and Trichuris suis-infected pigs evaluated by ELISPOT

    DEFF Research Database (Denmark)

    Steenhard, N. R.; Kringel, H.; Roepstorff, A.

    2007-01-01

    method is a valuable tool for future experimental settings as it enables repeated and parasite-specific measurement of IL-4 at protein level when investigating, for example, immunomodulatory properties of helminths. Furthermore, the method could be used to identify specific parasite antigens inducing IL......The objective of the present study was to develop an ELISPOT method to measure parasite-specific IL-4 producing cells during experimental Ascaris suum and Trichuris suis infections in pigs. In many experimental settings it is useful to be able to measure changes in specifically induced cytokines...

  19. Macrophages and mast cells in dystrophic masseter muscle: a light and electron microscopic study

    DEFF Research Database (Denmark)

    Kirkeby, S; Mikkelsen, H

    1988-01-01

    Macrophages and mast cells in masseter muscle from normal and dystrophic mice were studied by light and electron microscopy. Acid phosphatase activity and FITC-dextran were used to identify and describe macrophages. Toluidine blue was used as a marker for mast cells. In dystrophic muscle, the num......Macrophages and mast cells in masseter muscle from normal and dystrophic mice were studied by light and electron microscopy. Acid phosphatase activity and FITC-dextran were used to identify and describe macrophages. Toluidine blue was used as a marker for mast cells. In dystrophic muscle...

  20. Healthy and diseased striated muscle studied by analytical scanning electron microscopy with special reference to fibre type

    International Nuclear Information System (INIS)

    Wroblewski, R.

    1982-01-01

    X-ray microanalytical investigations of striated muscles in the scanning electron microscope are reviewed. The main part of the studies was performed on cryosections cut with a conventional cryostat operating at -20 degrees C to -40 degrees C. The preparation procedure including different types of attachment of the sections to the specimen holder is described in detail. The elemental changes in muscle are related to the muscle fibre type as demonstrated by histochemical methods or to histochemically demonstrated inclusions in diseased muscles. This is of great importance, because muscle disorders are often characterised by selective involvement of different muscle fibre types. The preparation methods of muscle for analytical scanning electron microscopy and the obtained results are compared with studies performed on thin cryo and epoxy sections, analysed in the transmission and scanning-transmission electron microscope. It is evident that X-ray microanalysis performed on thick cryosections provide a quick survey of the elemental composition of whole cells, and should be followed in interesting cases by close examination on the organelle level studied in thin cryosections in the transmission and scanning-transmission electron microscope

  1. Viability of Ascaris suum eggs in stored raw and separated liquid slurry

    DEFF Research Database (Denmark)

    Katakam, Kiran Kumar; Roepstorff, Allan Knud; Popovic, Olga

    2013-01-01

    SUMMARY Separation of pig slurry into solid and liquid fractions is gaining importance as a way to manage increasing volumes of slurry. In contrast to solid manure and slurry, little is known about pathogen survival in separated liquid slurry. The viability of Ascaris suum eggs, a conservative...... indicator of fecal pollution, and its association with ammonia was investigated in separated liquid slurry in comparison with raw slurry. For this purpose nylon bags with 6000 eggs each were placed in 1 litre bottles containing one of the two fractions for 308 days at 5 °C or 25 °C. Initial analysis...... of helminth eggs in the separated liquid slurry revealed 47 Ascaris eggs per gramme. At 25 °C, egg viability declined to zero with a similar trend in both raw slurry and the separated liquid slurry by day 308, a time when at 5 °C 88% and 42% of the eggs were still viable in separated liquid slurry and raw...

  2. Full scale validation of helminth ova (Ascaris suum) inactivation by different sludge treatment processes

    Energy Technology Data Exchange (ETDEWEB)

    Paulsrud, B.; Gjerde, B.; Lundar, A.

    2003-07-01

    The Norwegian sewage sludge regulation requires disinfection (hygienisation) of all sludges for land application, and one of the criteria is that disinfected sludge should not contain viable helminth ova. All disinfection processes have to be designed and operated in order to comply with this criteria, and four processes employed in Norway (thermophilic aerobic pre-treatment, pre-pasteurisation, thermal vacuum drying in membrane filter presses and lime treatment) have been tested in full scale by inserting semipermeable bags of Ascaris suum eggs into the processes for certain limes. For lime treatment supplementary laboratory tests have been conducted. The paper presents the results of the experiments, and it could be concluded that all processes, except lime treatment, could be operated at less stringent time-temperature regimes than commonly experienced at Norwegian plants today. (author)

  3. Experimental Ascaris suum infection in the pig: protective memory response after three immunizations and effect of intestinal adult worm population

    DEFF Research Database (Denmark)

    Jungersen, Gregers; Eriksen, Lis; Roepstorff, Allan

    1999-01-01

    The protective immune response to larval migration in pigs, with or without adult intestinal worm populations, 10 weeks after 3 weekly Ascaris suum inoculations, was studied in 45 pigs. Controlled adult worm populations were achieved by oral transfer of 10 adult worms to previously immunized pigs...... after anthelmintic drenching. A significant reduction in larval recovery from lungs on day 7, and small intestine on day 14, was observed in immunized pigs compared with previously uninfected control pigs after challenge inoculation. The strong anamnestic response to larval migration was characterized...

  4. Radiation hygienization of cattle and swine slurry with high energy electron beam

    International Nuclear Information System (INIS)

    Skowron, Krzysztof; Olszewska, Halina; Paluszak, Zbigniew; Zimek, Zbigniew; Kałuska, Iwona; Skowron, Karolina Jadwiga

    2013-01-01

    The research was carried out to assess the efficiency of radiation hygienization of cattle and swine slurry of different density using the high energy electron beam based on the inactivation rate of Salmonella ssp, Escherichia coli, Enterococcus spp and Ascaris suum eggs. The experiment was conducted with use of the linear electron accelerator Elektronika 10/10 in Institute of Nuclear Chemistry and Technology in Warsaw. The inoculated slurry samples underwent hygienization with high energy electron beam of 1, 3, 5, 7 and 10 kGy. Numbers of reisolated bacteria were determined according to the MPN method, using typical microbiological media. Theoretical lethal doses, D 90 doses and hygienization efficiency of high energy electron beam were determined. The theoretical lethal doses for all tested bacteria ranged from 3.63 to 8.84 kGy and for A. suum eggs from 4.07 to 5.83 kGy. Salmonella rods turned out to be the most sensitive and Enterococcus spp were the most resistant to electron beam hygienization. The effectiveness or radiation hygienization was lower in cattle than in swine slurry and in thick than in thin one. Also the species or even the serotype of bacteria determined the dose needed to inactivation of microorganisms. - Highlights: ► The hygienic efficiency of electron beam against slurry was researched. ► The hygienization efficiency depended on the slurry characteristics and microorganism species. ► In most of the cases 7 kGy dose was sufficient for slurry hygienization. ► Dose below 1 kGy allowed for 90% elimination of microorganism population. ► The radiation hygienization is a good alternative for typical slurry treatment methods

  5. Optimization of the agar-gel method for isolation of migrating Ascaris suum larvae from the liver and lungs of pigs

    DEFF Research Database (Denmark)

    Saeed, I.; Roepstorff, A.; Rasmussen, T.

    2001-01-01

    Experiments on use of an agar-gel method for recovery of migrating Ascaris suum larvae from the liver and lungs of pigs were conducted to obtain fast standardized methods. Subsamples of blended tissues of pig liver and lungs were mixed with agar to a final concentration of 1% agar and the larvae...... clean suspension which reduced the sample counting time. Blending the liver for 60 sec in a commercial blender showed significantly higher larvae recovery than blending for 30 sec. Addition of gentamycin to reduce bacterial growth during incubation, glucose to increase larval motility during migration...

  6. Integrating Suum-ngi Theology of Peace in Gindiri Theological Seminary Curriculum in Nigeria. An African Theological Perspective

    Directory of Open Access Journals (Sweden)

    Pokol, Benjamin J

    2015-08-01

    Full Text Available This article argues that Gindiri theological seminary in Nigeria has done little or nothing to include issues of peace in theological education for the pastors in Church of Christ in Nations (COCIN of Nigeria. Consequently the Church of Christ in Nations seems to have failed to engage adequately in promoting peace among their members in the national search for peace and religious tolerance in Nigeria. The article further argues that the theological seminary which produces pastors and lay church leaders for pastoral ministry has a responsibility to equip pastors with necessary tools for responding to peace challenges facing the country. Therefore, the article advocates for the mainstreaming of Suum-ngi theology of peace in the curriculum of Gindiri Theological Seminary.

  7. STRETCHY ELECTRONICS. Hierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles.

    Science.gov (United States)

    Liu, Z F; Fang, S; Moura, F A; Ding, J N; Jiang, N; Di, J; Zhang, M; Lepró, X; Galvão, D S; Haines, C S; Yuan, N Y; Yin, S G; Lee, D W; Wang, R; Wang, H Y; Lv, W; Dong, C; Zhang, R C; Chen, M J; Yin, Q; Chong, Y T; Zhang, R; Wang, X; Lima, M D; Ovalle-Robles, R; Qian, D; Lu, H; Baughman, R H

    2015-07-24

    Superelastic conducting fibers with improved properties and functionalities are needed for diverse applications. Here we report the fabrication of highly stretchable (up to 1320%) sheath-core conducting fibers created by wrapping carbon nanotube sheets oriented in the fiber direction on stretched rubber fiber cores. The resulting structure exhibited distinct short- and long-period sheath buckling that occurred reversibly out of phase in the axial and belt directions, enabling a resistance change of less than 5% for a 1000% stretch. By including other rubber and carbon nanotube sheath layers, we demonstrated strain sensors generating an 860% capacitance change and electrically powered torsional muscles operating reversibly by a coupled tension-to-torsion actuation mechanism. Using theory, we quantitatively explain the complementary effects of an increase in muscle length and a large positive Poisson's ratio on torsional actuation and electronic properties. Copyright © 2015, American Association for the Advancement of Science.

  8. Possible presence of common tyvelose-containing glycans in Trichinella L1 larvae and embryonated eggs of several nematodes

    Directory of Open Access Journals (Sweden)

    Dea-Ayuela M.A.

    2001-06-01

    Full Text Available A monoclonal antibody (mAb US4 recognising an epitope containing tyvelose within the T. spiralis L-1 muscle larvae (TSL-1 antigens was tested in western-blot against various antigenic preparations from different stages of the following nematodes: T. spiralis (L1,adult, T. muris (egg, L1, L3, adult, Ascaris suum (egg, adult, Toxocara canis (egg, adult, Anisakis simplex (L3 and Haemochus contortus (egg. Positive reaction was present in antigen preparations from L1 larvae of T. spiralis and T. muris and from embryonated eggs of T. muris, A. suum, T. canis and H. conlortus.

  9. Muscle pathology in myotonic dystrophy: light and electron microscopic investigation in eighteen patients.

    Science.gov (United States)

    Nadaj-Pakleza, A; Lusakowska, A; Sułek-Piątkowska, A; Krysa, W; Rajkiewicz, M; Kwieciński, H; Kamińska, A

    2011-05-01

    Myotonic dystrophy (DM) is the most common muscular dystrophy in adults. Two known genetic subtypes include DM1 (myotonic dystrophy type 1) and DM2 (myotonic dystrophy type 2). Genetic testing is considered as the only reliable diagnostic criterion in myotonic dystrophies. Relatively little is known about DM1 and DM2 myopathology. Thus, the aim of our study was to characterise light and electron microscopic features of DM1 and DM2 in patients with genetically proven types of the disease. We studied 3 DM1 cases and 15 DM2 cases from which muscle biopsies were taken for diagnostic purposes during the period from 1973 to 2006, before genetic testing became available at our hospital. The DM1 group included 3 males (age at biopsy 15-19). The DM2 group included 15 patients (5 men and 10 women, age at biopsy 26-60). The preferential type 1 fibre atrophy was seen in all three DM1 cases in light microscopy, and substantial central nucleation was present in two biopsies. Electron microscopy revealed central nuclei in all three examined muscle biopsies. No other structural or degenerative changes were detected, probably due to the young age of our patients. Central nucleation, prevalence of type 2 muscle fibres, and the presence of pyknotic nuclear clumps were observed in DM2 patients in light microscopy. Among the ultrastructural abnormalities observed in our DM2 group, the presence of internal nuclei, severely atrophied muscle fibres, and lipofuscin accumulation were consistent findings. In addition, a variety of ultrastructural abnormalities were identified by us in DM2. It appears that no single ultrastructural abnormality is characteristic for the DM2 muscle pathology. It seems, however, that certain constellations of morphological changes might be indicative of certain types of myotonic dystrophy.

  10. Useable diffraction data from a multiple microdomain-containing crystal of Ascaris suum As-p18 fatty-acid-binding protein using a microfocus beamline

    International Nuclear Information System (INIS)

    Gabrielsen, Mads; Riboldi-Tunnicliffe, Alan; Ibáñez-Shimabukuro, Marina; Griffiths, Kate; Roe, Andrew J.; Cooper, Alan; Smith, Brian O.; Córsico, Betina; Kennedy, Malcolm W.

    2012-01-01

    As-p18, an unusual fatty-acid-binding protein from a parasitic nematode, was expressed in bacteria, purified and crystallized. The use of a microfocus beamline was essential for data collection. As-p18 is a fatty-acid-binding protein from the parasitic nematode Ascaris suum. Although it exhibits sequence similarity to mammalian intracellular fatty-acid-binding proteins, it contains features that are unique to nematodes. Crystals were obtained, but initial diffraction data analysis revealed that they were composed of a number of ‘microdomains’. Interpretable data could only be collected using a microfocus beamline with a beam size of 12 × 8 µm

  11. Electron histochemical and autoradiographic studies of vascular smooth muscle cell

    International Nuclear Information System (INIS)

    Kameyama, Kohji; Aida, Takeo; Asano, Goro

    1982-01-01

    The authors have studied the vascular smooth muscle cell in the aorta and the arteries of brain, heart in autopsied cases, cholesterol fed rabbits and canine through electron histochemical and autoradiographic methods, using 3 H-proline and 3 H-thymidine. The vascular changes are variable presumably due to the functional and morphological difference of vessels. Aging, pathological condition and physiological requirement induce the disturbances of vascular functions as contractility. According to various pathological conditions, the smooth muscle cell altered their shape, surface properties and arrangement of subcellular organelles including changes in number. The morphological features of arteries during aging is characterized by the thickening of endothelium and media. Decreasing cellularity and increasing collagen contents in media. The autoradiographic and histochemical observations using periodic acid methenamine silver (PAM) and ruthenium red stains demonstrated that the smooth muscle cell is a connective tissue synthetic cell. The PAM impregnation have proved that the small bundle of microfilaments become associated with small conglomerate of collagen and elastic fibers. Cytochemical examination will provide sufficient evidence to establish the contribution of subcellular structure. The acid phosphatase play an important role in vascular disease and they are directly involved in cellular lipid metabolism in cholesterol fed animals, and the activity of Na-K ATPase on the plasma membrane may contribute to the regulation of vascular blood flow and vasospasms. Direct injury and subsequent abnormal contraction of smooth muscle cell may initiate increased permeability of plasma protein and lipid in the media layer and eventually may developed and enhance arteriosclerosis. (author)

  12. Actividad in vitro de los venenos de Lachesis muta y Bothrops atrox sobre la viabilidad y desarrollo embrionario de los huevos de Ascaris suum

    Directory of Open Access Journals (Sweden)

    Claudia Paredes

    2014-06-01

    Full Text Available Los venenos de serpientes son concentrados polienzimáticos cuya actividad biológica sobre algunas bacterias y protozoos ha sido comprobada. El objetivo principal del presente trabajo fue estudiar la actividad in vitro de los venenos totales de las serpientes Lachesis muta y Bothrops atrox sobre la viabilidad y el desarrollo embrionario de los huevos de Ascaris suum. Se emplearon los venenos totales en concentraciones de 2, 4, 8 y 16 mg/mL sobre huevos no embrionados y larvados in vitro. Se comparó la actividad de los venenos con la de otras sustancias como el hipoclorito de sodio al 5,25%, Albendazol (solución comercial y solución salina. Ambos venenos, en concentraciones de 4, 8 y 16 mg/mL, inhibieron la blastulación de estos huevos; hasta el sexto día de incubación; en cambio en concentración de 2 mg/mL la inhibición se dio hasta el cuarto día. Posteriormente iniciaron un proceso de embrionación aparentemente normal hasta la formación del estadio infectante. El veneno de B. atrox fue el que presentó el mayor efecto inhibitorio en concentración de 16 mg/mL. El hipoclorito de sodio destruyó el 100% de los huevos, mientras el albendazol ocasionó que los huevos iniciaran un proceso de segmentación anormal que originó su degeneración. Se concluye que los venenos de L. muta y B. atrox muestran actividad inhibitoria al inicio de la blastulación de los huevos de A. suum y no ejercen ningún efecto en los huevos larvados.

  13. An electron microscopic investigation into the possible source of new muscle fibres in teleost fish.

    Science.gov (United States)

    Stoiber, W; Sänger, A M

    1996-12-01

    This study is based on transmission electron microscopic (TEM) investigations of deep (fast, 'white') teleost fish muscle proliferation in early developmental stages of three European cyprinid species and the rainbow trout. Our fine structural findings provide evidence that early myotomal growth in these animals may utilize different mechanisms that are activated in close succession during early life history. First, initial enlargement of the deep muscle bulk in the embryo seems to be due to hypertrophy of the somite-cell derived stock of muscle fibres. Second, we suggest that deep muscle growth becomes additionally powered by attachment of presumptive myogenic cells that originate from and proliferate within the adjacent mesenchymal tissue lining. Third, mesenchyme-derived muscle cell precursors are thought to enter the myotomes via the myosepta. After migration between the pre-established muscle fibres these cells may function as myosatellite cells, thus at least partly providing the stem cell population for subsequent rapid hyperplastic growth. Finally, there is evidence that presumptive deep muscle satellite cells also proliferate by mitotic division in situ. A similar process of myogenic cell migration and proliferation may foster intermediate fibre differentiation. The model of myogenic cell migration is discussed in view of in vitro and in vivo data on satellite cell migratory power and with respect to temperature-induced and species dependent differences. As for the latter, our results indicate that patterns of muscle differentiation may diverge between a fast growing salmonid species and a moderately growing cyprinid species of similar final size. The model is compatible with the well-established idea that teleost muscle growth may rely on different subclasses of myosatellite cells.

  14. Anthelmintic properties of traditional African and Caribbean medicinal plants: identification of extracts with potent activity against Ascaris suum in vitro

    Directory of Open Access Journals (Sweden)

    Williams Andrew R.

    2016-01-01

    Full Text Available Ascariasis affects more than 1 billion people worldwide, mainly in developing countries, causing substantial morbidity. Current treatments for Ascaris infection are based on mass drug administration (MDA with synthetic anthelmintic drugs such as albendazole, however continual re-infection and the threat of drug resistance mean that complementary treatment options would be highly valuable. Here, we screened ethanolic extracts from 29 medicinal plants used in Africa (Ghana and the Caribbean (US Virgin Islands for in vitro anthelmintic properties against Ascaris suum, a swine parasite that is very closely related to the human A. lumbricoides. A wide variety of activities were seen in the extracts, from negligible to potent. Extracts from Clausena anisata, Zanthoxylum zanthoxyloides and Punica granatum were identified as the most potent with EC50 values of 74, 97 and 164 μg/mL, respectively. Our results encourage further investigation of their use as complementary treatment options for ascariasis, alongside MDA.

  15. A comparison of modifications of the McMaster method for the enumeration of Ascaris suum eggs in pig faecal samples.

    Science.gov (United States)

    Pereckiene, A; Kaziūnaite, V; Vysniauskas, A; Petkevicius, S; Malakauskas, A; Sarkūnas, M; Taylor, M A

    2007-10-21

    The comparative efficacies of seven published McMaster method modifications for faecal egg counting were evaluated on pig faecal samples containing Ascaris suum eggs. Comparisons were made as to the number of samples found to be positive by each of the methods, the total egg counts per gram (EPG) of faeces, the variations in EPG obtained in the samples examined, and the ease of use of each of the methods. Each method was evaluated after the examination of 30 samples of faeces. The positive samples were identified by counting A. suum eggs in one, two and three sections of newly designed McMaster chamber. In the present study compared methods were reported by: I-Henriksen and Aagaard [Henriksen, S.A., Aagaard, K.A., 1976. A simple flotation and McMaster method. Nord. Vet. Med. 28, 392-397]; II-Kassai [Kassai, T., 1999. Veterinary Helminthology. Butterworth-Heinemann, Oxford, 260 pp.]; III and IV-Urquhart et al. [Urquhart, G.M., Armour, J., Duncan, J.L., Dunn, A.M., Jennings, F.W., 1996. Veterinary Parasitology, 2nd ed. Blackwell Science Ltd., Oxford, UK, 307 pp.] (centrifugation and non-centrifugation methods); V and VI-Grønvold [Grønvold, J., 1991. Laboratory diagnoses of helminths common routine methods used in Denmark. In: Nansen, P., Grønvold, J., Bjørn, H. (Eds.), Seminars on Parasitic Problems in Farm Animals Related to Fodder Production and Management. The Estonian Academy of Sciences, Tartu, Estonia, pp. 47-48] (salt solution, and salt and glucose solution); VII-Thienpont et al. [Thienpont, D., Rochette, F., Vanparijs, O.F.J., 1986. Diagnosing Helminthiasis by Coprological Examination. Coprological Examination, 2nd ed. Janssen Research Foundation, Beerse, Belgium, 205 pp.]. The number of positive samples by examining single section ranged from 98.9% (method I), to 51.1% (method VII). Only with methods I and II, there was a 100% positivity in two out of three of the chambers examined, and FEC obtained using these methods were significantly (pcoefficient

  16. 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

  17. High Intensity Interval Training (HIIT) Induces Specific Changes in Respiration and Electron Leakage in the Mitochondria of Different Rat Skeletal Muscles.

    Science.gov (United States)

    Ramos-Filho, Dionizio; Chicaybam, Gustavo; de-Souza-Ferreira, Eduardo; Guerra Martinez, Camila; Kurtenbach, Eleonora; Casimiro-Lopes, Gustavo; Galina, Antonio

    2015-01-01

    High intensity interval training (HIIT) is characterized by vigorous exercise with short rest intervals. Hydrogen peroxide (H2O2) plays a key role in muscle adaptation. This study aimed to evaluate whether HIIT promotes similar H2O2 formation via O2 consumption (electron leakage) in three skeletal muscles with different twitch characteristics. Rats were assigned to two groups: sedentary (n=10) and HIIT (n=10, swimming training). We collected the tibialis anterior (TA-fast), gastrocnemius (GAST-fast/slow) and soleus (SOL-slow) muscles. The fibers were analyzed for mitochondrial respiration, H2O2 production and citrate synthase (CS) activity. A multi-substrate (glycerol phosphate (G3P), pyruvate, malate, glutamate and succinate) approach was used to analyze the mitochondria in permeabilized fibers. Compared to the control group, oxygen flow coupled to ATP synthesis, complex I and complex II was higher in the TA of the HIIT group by 1.5-, 3.0- and 2.7-fold, respectively. In contrast, oxygen consumed by mitochondrial glycerol phosphate dehydrogenase (mGPdH) was 30% lower. Surprisingly, the oxygen flow coupled to ATP synthesis was 42% lower after HIIT in the SOL. Moreover, oxygen flow coupled to ATP synthesis and complex II was higher by 1.4- and 2.7-fold in the GAST of the HIIT group. After HIIT, CS activity increased 1.3-fold in the TA, and H2O2 production was 1.3-fold higher in the TA at sites containing mGPdH. No significant differences in H2O2 production were detected in the SOL. Surprisingly, HIIT increased H2O2 production in the GAST via complex II, phosphorylation, oligomycin and antimycin by 1.6-, 1.8-, 2.2-, and 2.2-fold, respectively. Electron leakage was 3.3-fold higher in the TA with G3P and 1.8-fold higher in the GAST with multiple substrates. Unexpectedly, the HIIT protocol induced different respiration and electron leakage responses in different types of muscle.

  18. High Intensity Interval Training (HIIT Induces Specific Changes in Respiration and Electron Leakage in the Mitochondria of Different Rat Skeletal Muscles.

    Directory of Open Access Journals (Sweden)

    Dionizio Ramos-Filho

    Full Text Available High intensity interval training (HIIT is characterized by vigorous exercise with short rest intervals. Hydrogen peroxide (H2O2 plays a key role in muscle adaptation. This study aimed to evaluate whether HIIT promotes similar H2O2 formation via O2 consumption (electron leakage in three skeletal muscles with different twitch characteristics. Rats were assigned to two groups: sedentary (n=10 and HIIT (n=10, swimming training. We collected the tibialis anterior (TA-fast, gastrocnemius (GAST-fast/slow and soleus (SOL-slow muscles. The fibers were analyzed for mitochondrial respiration, H2O2 production and citrate synthase (CS activity. A multi-substrate (glycerol phosphate (G3P, pyruvate, malate, glutamate and succinate approach was used to analyze the mitochondria in permeabilized fibers. Compared to the control group, oxygen flow coupled to ATP synthesis, complex I and complex II was higher in the TA of the HIIT group by 1.5-, 3.0- and 2.7-fold, respectively. In contrast, oxygen consumed by mitochondrial glycerol phosphate dehydrogenase (mGPdH was 30% lower. Surprisingly, the oxygen flow coupled to ATP synthesis was 42% lower after HIIT in the SOL. Moreover, oxygen flow coupled to ATP synthesis and complex II was higher by 1.4- and 2.7-fold in the GAST of the HIIT group. After HIIT, CS activity increased 1.3-fold in the TA, and H2O2 production was 1.3-fold higher in the TA at sites containing mGPdH. No significant differences in H2O2 production were detected in the SOL. Surprisingly, HIIT increased H2O2 production in the GAST via complex II, phosphorylation, oligomycin and antimycin by 1.6-, 1.8-, 2.2-, and 2.2-fold, respectively. Electron leakage was 3.3-fold higher in the TA with G3P and 1.8-fold higher in the GAST with multiple substrates. Unexpectedly, the HIIT protocol induced different respiration and electron leakage responses in different types of muscle.

  19. Association between Thigh Muscle Volume and Leg Muscle Power in Older Women.

    Directory of Open Access Journals (Sweden)

    Ulrich Lindemann

    Full Text Available The construct of sarcopenia is still discussed with regard to best appropriate measures of muscle volume and muscle function. The aim of this post-hoc analysis of a cross-sectional experimental study was to investigate and describe the hierarchy of the association between thigh muscle volume and measurements of functional performance in older women. Thigh muscle volume of 68 independently living older women (mean age 77.6 years was measured via magnetic resonance imaging. Isometric strength was assessed for leg extension in a movement laboratory in sitting position with the knee flexed at 90° and for hand grip. Maximum and habitual gait speed was measured on an electronic walk way. Leg muscle power was measured during single leg push and during sit-to-stand performance. Thigh muscle volume was associated with sit-to-stand performance power (r = 0.628, leg push power (r = 0.550, isometric quadriceps strength (r = 0.442, hand grip strength (r = 0.367, fast gait speed (r = 0.291, habitual gait speed (r = 0.256, body mass index (r = 0.411 and age (r = -0.392. Muscle power showed the highest association with thigh muscle volume in healthy older women. Sit-to-stand performance power showed an even higher association with thigh muscle volume compared to single leg push power.

  20. Inhibition of muscle spindle afferent activity during masseter muscle fatigue in the rat.

    Science.gov (United States)

    Brunetti, Orazio; Della Torre, Giovannella; Lucchi, Maria Luisa; Chiocchetti, Roberto; Bortolami, Ruggero; Pettorossi, Vito Enrico

    2003-09-01

    The influence of muscle fatigue on the jaw-closing muscle spindle activity has been investigated by analyzing: (1) the field potentials evoked in the trigeminal motor nucleus (Vmot) by trigeminal mesencephalic nucleus (Vmes) stimulation, (2) the orthodromic and antidromic responses evoked in the Vmes by stimulation of the peripheral and central axons of the muscle proprioceptive afferents, and (3) the extracellular unitary discharge of masseter muscle spindles recorded in the Vmes. The masseter muscle was fatigued by prolonged tetanic masseter nerve electrical stimulation. Pre- and postsynaptic components of the potentials evoked in the Vmot showed a significant reduction in amplitude following muscle fatigue. Orthodromic and antidromic potentials recorded in the Vmes also showed a similar amplitude decrease. Furthermore, muscle fatigue caused a decrease of the discharge frequency of masseter muscle spindle afferents in most of the examined units. The inhibition of the potential amplitude and discharge frequency was strictly correlated with the extent of muscle fatigue and was mediated by the group III and IV afferent muscle fibers activated by fatigue. In fact, the inhibitory effect was abolished by capsaicin injection in the masseter muscle that provokes selective degeneration of small afferent muscle fibers containing neurokinins. We concluded that fatigue signals originating from the muscle and traveling through capsaicin-sensitive fibers are able to diminish the proprioceptive input by a central presynaptic influence. In the second part of the study, we examined the central projection of the masseter small afferents sensitive to capsaicin at the electron-microscopic level. Fiber degeneration was induced by injecting capsaicin into the masseter muscle. Degenerating terminals were found on the soma and stem process in Vmes and on the dendritic tree of neurons in Vmot. This suggests that small muscle afferents may influence the muscle spindle activity through

  1. A method for 3D-reconstruction of a muscle thick filament using the tilt series images of a single filament electron tomogram.

    Science.gov (United States)

    Márquez, G; Pinto, A; Alamo, L; Baumann, B; Ye, F; Winkler, H; Taylor, K; Padrón, R

    2014-05-01

    Myosin interacting-heads (MIH) motifs are visualized in 3D-reconstructions of thick filaments from striated muscle. These reconstructions are calculated by averaging methods using images from electron micrographs of grids prepared using numerous filament preparations. Here we propose an alternative method to calculate the 3D-reconstruction of a single thick filament using only a tilt series images recorded by electron tomography. Relaxed thick filaments, prepared from tarantula leg muscle homogenates, were negatively stained. Single-axis tilt series of single isolated thick filaments were obtained with the electron microscope at a low electron dose, and recorded on a CCD camera by electron tomography. An IHRSR 3D-recontruction was calculated from the tilt series images of a single thick filament. The reconstruction was enhanced by including in the search stage dual tilt image segments while only single tilt along the filament axis is usually used, as well as applying a band pass filter just before the back projection. The reconstruction from a single filament has a 40 Å resolution and clearly shows the presence of MIH motifs. In contrast, the electron tomogram 3D-reconstruction of the same thick filament - calculated without any image averaging and/or imposition of helical symmetry - only reveals MIH motifs infrequently. This is - to our knowledge - the first application of the IHRSR method to calculate a 3D reconstruction from tilt series images. This single filament IHRSR reconstruction method (SF-IHRSR) should provide a new tool to assess structural differences between well-ordered thick (or thin) filaments in a grid by recording separately their electron tomograms. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2011-06-01

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

  3. Bone-and-muscle-equivalent solid chemical dose meters for photon and electron doses above one kilorad

    International Nuclear Information System (INIS)

    McLaughlin, W.L.; Rosenstein, M.; Levine, H.

    1975-01-01

    Conventional solid dose meters, such as plastic films, powders, emulsions, glasses, ceramics and gels, have a response to ionizing photons and electrons that varies markedly over a broad spectrum when compared with the absorption characteristics of biological tissues. New radiochromic dyed plastic dose meters have been developed with X- and gamma ray and electron energy absorption cross-sections (calculated) and radiation energy responses (experimental) corresponding approximately to those for human muscle and bone, for a spectrum from a few keV to at least 10 MeV. Three-dimensional solid dose meters useful over the absorbed dose range of 10 3 to 10 6 rad are formed by thermosetting a selected combination of monomers containing the radiochromic dye in solution. Thin-film dose meters for the dose range 10 5 to 10 7 rad are formed by casting on optically flat surfaces strippable layers of special combinations of polymers and dyes in solution. The response of these systems to X- and gamma rays and electrons has been studied over various radiation spectra, dose-rates and temperatures during irradiation. (author)

  4. A Biomimetic Conductive Tendril for Ultrastretchable and Integratable Electronics, Muscles, and Sensors.

    Science.gov (United States)

    Cheng, Yin; Wang, Ranran; Chan, Kwok Hoe; Lu, Xin; Sun, Jing; Ho, Ghim Wei

    2018-04-24

    Adaptive tendril coiling of climbing plants has long inspired the artificial soft microsystem for actuation and morphing. The current bionic research efforts on tendril coiling focus on either the preparation of materials with the coiling geometry or the design of self-shaping materials. However, the realization of two key functional features of the tendril, the spring-like buffering connection and the axial contraction, remains elusive. Herein, we devise a conductive tendril by fusing conductive yarns into tendril configuration, bypassing the prevailing conductivity constraints and mechanical limitations. The conductive tendril not only inherits an electrophysiology buffering mechanics with exceptional conductance retention ability against extreme stretching but also exhibits excellent contractive actuation performance. The integrative design of the ultraelastic conductive tendril shows a combination of compliant mobility, actuation, and sensory capabilities. Such smart biomimetic material holds great prospects in the fields of ultrastretchable electronics, artificial muscles, and wearable bioelectronic therapeutics.

  5. Electron Tomography of Cryofixed, Isometrically Contracting Insect Flight Muscle Reveals Novel Actin-Myosin Interactions

    International Nuclear Information System (INIS)

    Wu, Shenping; Liu, Jun; Reedy, Mary C.; Tregear, Richard T.; Winkler, Hanspeter; Franzini-Armstrong, Clara; Sasaki, Hiroyuki; Lucaveche, Carmen; Goldman, Yale E.; Reedy, Michael K.; Taylor, Kenneth A.

    2010-01-01

    Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ. We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filament density independent of the myosin. Actin-myosin attachments can now be assigned as weak or strong by their motor domain orientation relative to actin. Myosin attachments were quantified everywhere along the thin filament including troponin. Strong binding myosin attachments are found on only four F-actin subunits, the 'target zone', situated exactly midway between successive troponin complexes. They show an axial lever arm range of 77 o /12.9 nm. The lever arm azimuthal range of strong binding attachments has a highly skewed, 127 o range compared with X-ray crystallographic structures. Two types of weak actin attachments are described. One type, found exclusively in the target zone, appears to represent pre-working-stroke intermediates. The other, which contacts tropomyosin rather than actin, is positioned M-ward of the target zone, i.e. the position toward which thin filaments slide during shortening. We present a model for the weak to strong transition in the myosin ATPase cycle that incorporates azimuthal movements of the motor domain on actin. Stress/strain in the S2 domain may explain azimuthal lever arm changes in the strong binding attachments. The results support previous conclusions that the weak attachments preceding force generation are very different from

  6. Electron tomography of cryofixed, isometrically contracting insect flight muscle reveals novel actin-myosin interactions.

    Directory of Open Access Journals (Sweden)

    Shenping Wu

    2010-09-01

    Full Text Available Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ.We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filament density independent of the myosin. Actin-myosin attachments can now be assigned as weak or strong by their motor domain orientation relative to actin. Myosin attachments were quantified everywhere along the thin filament including troponin. Strong binding myosin attachments are found on only four F-actin subunits, the "target zone", situated exactly midway between successive troponin complexes. They show an axial lever arm range of 77°/12.9 nm. The lever arm azimuthal range of strong binding attachments has a highly skewed, 127° range compared with X-ray crystallographic structures. Two types of weak actin attachments are described. One type, found exclusively in the target zone, appears to represent pre-working-stroke intermediates. The other, which contacts tropomyosin rather than actin, is positioned M-ward of the target zone, i.e. the position toward which thin filaments slide during shortening.We present a model for the weak to strong transition in the myosin ATPase cycle that incorporates azimuthal movements of the motor domain on actin. Stress/strain in the S2 domain may explain azimuthal lever arm changes in the strong binding attachments. The results support previous conclusions that the weak attachments preceding force generation are very

  7. Structural Insights into the Molecular Design of Flutolanil Derivatives Targeted for Fumarate Respiration of Parasite Mitochondria

    Directory of Open Access Journals (Sweden)

    Daniel Ken Inaoka

    2015-07-01

    Full Text Available Recent studies on the respiratory chain of Ascaris suum showed that the mitochondrial NADH-fumarate reductase system composed of complex I, rhodoquinone and complex II plays an important role in the anaerobic energy metabolism of adult A. suum. The system is the major pathway of energy metabolism for adaptation to a hypoxic environment not only in parasitic organisms, but also in some types of human cancer cells. Thus, enzymes of the pathway are potential targets for chemotherapy. We found that flutolanil is an excellent inhibitor for A. suum complex II (IC50 = 0.058 μM but less effectively inhibits homologous porcine complex II (IC50 = 45.9 μM. In order to account for the specificity of flutolanil to A. suum complex II from the standpoint of structural biology, we determined the crystal structures of A. suum and porcine complex IIs binding flutolanil and its derivative compounds. The structures clearly demonstrated key interactions responsible for its high specificity to A. suum complex II and enabled us to find analogue compounds, which surpass flutolanil in both potency and specificity to A. suum complex II. Structures of complex IIs binding these compounds will be helpful to accelerate structure-based drug design targeted for complex IIs.

  8. Structural Insights into the Molecular Design of Flutolanil Derivatives Targeted for Fumarate Respiration of Parasite Mitochondria.

    Science.gov (United States)

    Inaoka, Daniel Ken; Shiba, Tomoo; Sato, Dan; Balogun, Emmanuel Oluwadare; Sasaki, Tsuyoshi; Nagahama, Madoka; Oda, Masatsugu; Matsuoka, Shigeru; Ohmori, Junko; Honma, Teruki; Inoue, Masayuki; Kita, Kiyoshi; Harada, Shigeharu

    2015-07-07

    Recent studies on the respiratory chain of Ascaris suum showed that the mitochondrial NADH-fumarate reductase system composed of complex I, rhodoquinone and complex II plays an important role in the anaerobic energy metabolism of adult A. suum. The system is the major pathway of energy metabolism for adaptation to a hypoxic environment not only in parasitic organisms, but also in some types of human cancer cells. Thus, enzymes of the pathway are potential targets for chemotherapy. We found that flutolanil is an excellent inhibitor for A. suum complex II (IC50 = 0.058 μM) but less effectively inhibits homologous porcine complex II (IC50 = 45.9 μM). In order to account for the specificity of flutolanil to A. suum complex II from the standpoint of structural biology, we determined the crystal structures of A. suum and porcine complex IIs binding flutolanil and its derivative compounds. The structures clearly demonstrated key interactions responsible for its high specificity to A. suum complex II and enabled us to find analogue compounds, which surpass flutolanil in both potency and specificity to A. suum complex II. Structures of complex IIs binding these compounds will be helpful to accelerate structure-based drug design targeted for complex IIs.

  9. Muscle glycogen stores and fatigue

    DEFF Research Database (Denmark)

    Ørtenblad, Niels; Westerblad, Håkan; Nielsen, Joachim

    2013-01-01

      Studies performed at the beginning of the last century revealed the importance of carbohydrate as a fuel during exercise, and the importance of muscle glycogen on performance has subsequently been confirmed in numerous studies. However, the link between glycogen depletion and impaired muscle...... function during fatigue is not well understood and a direct cause-and-effect relationship between glycogen and muscle function remains to be established. The use of electron microscopy has revealed that glycogen is not homogeneously distributed in skeletal muscle fibres, but rather localized in distinct...... pools. Furthermore, each glycogen granule has its own metabolic machinery with glycolytic enzymes and regulating proteins. One pool of such glycogenolytic complexes is localized within the myofibrils in close contact with key proteins involved in the excitation-contraction coupling and Ca2+ release from...

  10. Physiological aspects of the subcellular localization of glycogen in skeletal muscle

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Ørtenblad, Niels

    2013-01-01

    Glucose is stored in skeletal muscle fibers as glycogen, a branched-chain polymer observed in electron microscopy images as roughly spherical particles (known as β-particles of 10-45 nm in diameter), which are distributed in distinct localizations within the myofibers and are physically associated...... investigated the role and regulation of these distinct deposits of glycogen. In this report, we review the available literature regarding the subcellular localization of glycogen in skeletal muscle as investigated by electron microscopy studies and put this into perspective in terms of the architectural......, topological, and dynamic organization of skeletal muscle fibers. In summary, the distribution of glycogen within skeletal muscle fibers has been shown to depend on the fiber phenotype, individual training status, short-term immobilization, and exercise and to influence both muscle contractility...

  11. Satellite Cells CD44 Positive Drive Muscle Regeneration in Osteoarthritis Patients

    Science.gov (United States)

    Scimeca, Manuel; Bonanno, Elena; Piccirilli, Eleonora; Baldi, Jacopo; Mauriello, Alessandro; Orlandi, Augusto; Tancredi, Virginia; Gasbarra, Elena; Tarantino, Umberto

    2015-01-01

    Age-related bone diseases, such as osteoarthritis and osteoporosis, are strongly associated with sarcopenia and muscle fiber atrophy. In this study, we analyzed muscle biopsies in order to demonstrate that, in osteoarthritis patients, both osteophytes formation and regenerative properties of muscle stem cells are related to the same factors. In particular, thanks to immunohistochemistry, transmission electron microscopy, and immunogold labeling we investigated the role of BMP-2 in muscle stem cells activity. In patients with osteoarthritis both immunohistochemistry and transmission electron microscopy allowed us to note a higher number of CD44 positive satellite muscle cells forming syncytium. Moreover, the perinuclear and cytoplasmic expression of BMP-2 assessed by in situ molecular characterization of satellite cells syncytia suggest a very strict correlation between BMP-2 expression and muscle regeneration capability. Summing up, the higher BMP-2 expression in osteoarthritic patients could explain the increased bone mineral density as well as decreased muscle atrophy in osteoarthrosic patients. In conclusion, our results suggest that the control of physiological BMP-2 balance between bone and muscle tissues may be considered as a potential pharmacological target in bone-muscle related pathology. PMID:26101529

  12. Satellite Cells CD44 Positive Drive Muscle Regeneration in Osteoarthritis Patients

    Directory of Open Access Journals (Sweden)

    Manuel Scimeca

    2015-01-01

    Full Text Available Age-related bone diseases, such as osteoarthritis and osteoporosis, are strongly associated with sarcopenia and muscle fiber atrophy. In this study, we analyzed muscle biopsies in order to demonstrate that, in osteoarthritis patients, both osteophytes formation and regenerative properties of muscle stem cells are related to the same factors. In particular, thanks to immunohistochemistry, transmission electron microscopy, and immunogold labeling we investigated the role of BMP-2 in muscle stem cells activity. In patients with osteoarthritis both immunohistochemistry and transmission electron microscopy allowed us to note a higher number of CD44 positive satellite muscle cells forming syncytium. Moreover, the perinuclear and cytoplasmic expression of BMP-2 assessed by in situ molecular characterization of satellite cells syncytia suggest a very strict correlation between BMP-2 expression and muscle regeneration capability. Summing up, the higher BMP-2 expression in osteoarthritic patients could explain the increased bone mineral density as well as decreased muscle atrophy in osteoarthrosic patients. In conclusion, our results suggest that the control of physiological BMP-2 balance between bone and muscle tissues may be considered as a potential pharmacological target in bone-muscle related pathology.

  13. 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.

  14. 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...... 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...

  15. Modulation of redox regulatory molecules and electron transport chain activity in muscle of air breathing fish Heteropneustes fossilis under air exposure stress.

    Science.gov (United States)

    Paital, Biswaranjan

    2014-01-01

    Responses of redox regulatory system to long-term survival (>18 h) of the catfish Heteropneustes fossilis in air are not yet understood. Lipid and protein oxidation level, oxidant (H2O2) generation, antioxidative status (levels of superoxide dismutase, catalase, glutathione peroxidase and reductase, ascorbic acid and non-protein sulfhydryl) and activities of respiratory complexes (I, II, III and IV) in mitochondria were investigated in muscle of H. fossilis under air exposure condition (0, 3, 6, 12 and 18 h at 25 °C). The increased levels of both H2O2 and tissue oxidation were observed due to the decreased activities of antioxidant enzymes in muscle under water deprivation condition. However, ascorbic acid and non-protein thiol groups were the highest at 18 h air exposure time. A linear increase in complex II activity with air exposure time and an increase up to 12 h followed by a decrease in activity of complex I at 18 h were observed. Negative correlation was observed for complex III and V activity with exposure time. Critical time to modulate the above parameters was found to be 3 h air exposure. Dehydration induced oxidative stress due to modulation of electron transport chain and redox metabolizing enzymes in muscle of H. fossilis was clearly observed. Possible contribution of redox regulatory system in muscle tissue of the fish for long-term survival in air is elucidated. Results of the present study may be useful to understand the redox metabolism in muscle of fishes those are exposed to air in general and air breathing fishes in particular.

  16. Muscle Deoxygenation Causes Muscle Fatigue

    Science.gov (United States)

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

    1999-01-01

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

  17. Photothermal imaging of skeletal muscle mitochondria.

    Science.gov (United States)

    Tomimatsu, Toru; Miyazaki, Jun; Kano, Yutaka; Kobayashi, Takayoshi

    2017-06-01

    The morphology and topology of mitochondria provide useful information about the physiological function of skeletal muscle. Previous studies of skeletal muscle mitochondria are based on observation with transmission, scanning electron microscopy or fluorescence microscopy. In contrast, photothermal (PT) microscopy has advantages over the above commonly used microscopic techniques because of no requirement for complex sample preparation by fixation or fluorescent-dye staining. Here, we employed the PT technique using a simple diode laser to visualize skeletal muscle mitochondria in unstained and stained tissues. The fine mitochondrial network structures in muscle fibers could be imaged with the PT imaging system, even in unstained tissues. PT imaging of tissues stained with toluidine blue revealed the structures of subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria and the swelling behavior of mitochondria in damaged muscle fibers with sufficient image quality. PT image analyses based on fast Fourier transform (FFT) and Grey-level co-occurrence matrix (GLCM) were performed to derive the characteristic size of mitochondria and to discriminate the image patterns of normal and damaged fibers.

  18. Ultrastructural pathological study on skeletal muscle injury in rabbit after a high-dose radiation

    International Nuclear Information System (INIS)

    Sun Wei; Ni Xinchu; Sun Suping; Cai Leiming; Yu Jingping; Wang Jian; Nie Bin; Sun Zhiqiang; Ni Xinye; Cao Xiufeng

    2012-01-01

    Objective: To establish a rabbit model of radiation-induced skeletal muscle injury in order to study the ultrastructural pathological changes and underlying mechanism. Methods: 28 New Zealand rabbits were randomly divided into 2 groups with 16 rabbits in experimental group and 12 rabbits in control group. The experimental rabbits were irradiated on hip with a single dose of 80 Gy of 9 MeV electrons from a linear accelerator. 1 month and 6 months after irradiation the pathological changes were respectively observed under light microscope and electron microscope. Results: One month after irradiation, the morphologic changes including degeneration, necrosis of muscle cells, and hemorrhage between the muscle cells were observed under light microscope and the swelling of myofibrillae, blurring of light and shade band, vacuolar degeneration of mitochondria and amorphous areas of necrosis were observed under electron microscope. Six months after irradiation, the morphologic changes of nucleolus chips, fibrous connective tissue, thickening of vascular wall and vascular congestion between the muscle cells and the amorphous areas of necrosis in the experimental group were much more serious than those of 1 month after irradiation. In addition, the myofilaments were lost in degeneration areas and the sarcomere became shorten. Observation with electron microscope showed that the mitochondrial size and its morphological changes were varied and the amounts of collagen between myofibrillaes were increased 6 months after irradiation. Conclusions: A rabbit model of high-dose irradiated skeleton muscle injury was successfully established with a single dose of 80 Gy of 9 MeV electrons from a linear accelerator. The degeneration and necrosis of muscle cells may be promoted by mitochondrial and vascular injury, degeneration of vessel and nerve fiber. (authors)

  19. Synchronous monitoring of muscle dynamics and electromyogram

    Science.gov (United States)

    Zakir Hossain, M.; Grill, Wolfgang

    2011-04-01

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

  20. 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.

  1. The Skeletal Muscle Satellite Cell

    Science.gov (United States)

    2011-01-01

    The skeletal muscle satellite cell was first described and named based on its anatomic location between the myofiber plasma and basement membranes. In 1961, two independent studies by Alexander Mauro and Bernard Katz provided the first electron microscopic descriptions of satellite cells in frog and rat muscles. These cells were soon detected in other vertebrates and acquired candidacy as the source of myogenic cells needed for myofiber growth and repair throughout life. Cultures of isolated myofibers and, subsequently, transplantation of single myofibers demonstrated that satellite cells were myogenic progenitors. More recently, satellite cells were redefined as myogenic stem cells given their ability to self-renew in addition to producing differentiated progeny. Identification of distinctively expressed molecular markers, in particular Pax7, has facilitated detection of satellite cells using light microscopy. Notwithstanding the remarkable progress made since the discovery of satellite cells, researchers have looked for alternative cells with myogenic capacity that can potentially be used for whole body cell-based therapy of skeletal muscle. Yet, new studies show that inducible ablation of satellite cells in adult muscle impairs myofiber regeneration. Thus, on the 50th anniversary since its discovery, the satellite cell’s indispensable role in muscle repair has been reaffirmed. PMID:22147605

  2. Preferential type II muscle fiber damage from plyometric exercise.

    Science.gov (United States)

    Macaluso, Filippo; Isaacs, Ashwin W; Myburgh, Kathryn H

    2012-01-01

    Plyometric training has been successfully used in different sporting contexts. Studies that investigated the effect of plyometric training on muscle morphology are limited, and results are controversial with regard to which muscle fiber type is mainly affected. To analyze the skeletal muscle structural and ultrastructural change induced by an acute bout of plyometric exercise to determine which type of muscle fibers is predominantly damaged. Descriptive laboratory study. Research laboratory. Eight healthy, untrained individuals (age = 22 ± 1 years, height = 179.2 ± 6.4 cm, weight = 78.9 ± 5.9 kg). Participants completed an acute bout of plyometric exercise (10 sets of 10 squat-jumps with a 1-minute rest between sets). Blood samples were collected 9 days and immediately before and 6 hours and 1, 2, and 3 days after the acute intervention. Muscle samples were collected 9 days before and 3 days after the exercise intervention. Blood samples were analyzed for creatine kinase activity. Muscle biopsies were analyzed for damage using fluorescent and electron transmission microscopy. Creatine kinase activity peaked 1 day after the exercise bout (529.0 ± 317.8 U/L). Immunofluorescence revealed sarcolemmal damage in 155 of 1616 fibers analyzed. Mainly fast-twitch fibers were damaged. Within subgroups, 7.6% of type I fibers, 10.3% of type IIa fibers, and 14.3% of type IIx fibers were damaged as assessed by losses in dystrophin staining. Similar damage was prevalent in IIx and IIa fibers. Electron microscopy revealed clearly distinguishable moderate and severe sarcomere damage, with damage quantifiably predominant in type II muscle fibers of both the glycolytic and oxidative subtypes (86% and 84%, respectively, versus only 27% of slow-twitch fibers). We provide direct evidence that a single bout of plyometric exercise affected mainly type II muscle fibers.

  3. Cerium oxide nanozyme modulate the ‘exercise’ redox biology of skeletal muscle

    Science.gov (United States)

    Arya, Aditya; Sethy, Niroj Kumar; Gangwar, Anamika; Bhargava, Neelima; Dubey, Amarish; Roy, Manas; Srivastava, Gaurav; Singh, Sushil Kumar; Das, Mainak; Bhargava, Kalpana

    2017-05-01

    ‘Exercise’ is a double-edged sword for the skeletal muscle. Small amount of ROS generated during mild exercise, is essential for normal force generation; whereas large quantity of ROS generated during intense exercise, may cause contractile dysfunction, resulting in muscle weakness and fatigue. One of the key question in skeletal muscle physiology is ‘could antioxidant therapy improve the skeletal muscle endurance? A question, which has resulted in contradictory experimental findings till this date. This work has addressed this ‘very question’ using a synthetic, inorganic, antioxidant nano-material viz., ‘cerium oxide nanozyme’ (CON). It has been introduced in the rat by intramuscular injection, and the skeletal muscle endurance has been evaluated. Intramuscular injections of CON, concurrent with exercise, enhanced muscle mass, glycogen and ATP content, type I fiber ratio, thus resulting in significantly higher muscle endurance. Electron microscope studies confirmed the presence of CON in the vicinity of muscle mitochondria. There was an increase in the number and size of the muscle mitochondria in the CON treated muscle, following exercise, as compared to the untreated group with only exercised muscle. Quantitative proteomics data and subsequent biological network analysis studies, identified higher levels of oxidative phosphorylation, TCA cycle output and glycolysis in CON supplemented exercised muscle over only exercised muscle. This was further associated with significant increase in the mitochondrial respiratory capacity and muscle contraction, primarily due to higher levels of electron transport chain proteins like NDUFA9, SDHA, ATP5B and ATP5D, which were validated by real-time PCR and western blotting. Along with this, persistence of CON in muscle was evaluated with ICP-MS analysis, which revealed clearance of the particles after 90 d, without exhibiting any inflammation or adverse affects on the health of the experimental animals. Thus a

  4. Wireless electronic-tattoo for long-term high fidelity facial muscle recordings

    Science.gov (United States)

    Inzelberg, Lilah; David Pur, Moshe; Steinberg, Stanislav; Rand, David; Farah, Maroun; Hanein, Yael

    2017-05-01

    Facial surface electromyography (sEMG) is a powerful tool for objective evaluation of human facial expressions and was accordingly suggested in recent years for a wide range of psychological and neurological assessment applications. Owing to technical challenges, in particular the cumbersome gelled electrodes, the use of facial sEMG was so far limited. Using innovative facial temporary tattoos optimized specifically for facial applications, we demonstrate the use of sEMG as a platform for robust identification of facial muscle activation. In particular, differentiation between diverse facial muscles is demonstrated. We also demonstrate a wireless version of the system. The potential use of the presented technology for user-experience monitoring and objective psychological and neurological evaluations is discussed.

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

    Science.gov (United States)

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

    2016-04-01

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

  6. A novel electrical model of nerve and muscle using Pspice

    CERN Document Server

    Peasgood, W; Lam, C K; Armstrong, A G; Wood, W

    2003-01-01

    In this work, a model is developed to simulate the biological processes involved in nerve fibre transmission and subsequent muscle contraction. The model has been based on approximating biological structure and function to electrical circuits and as such was implemented on an electronics simulation software package called Pspice. Models of nerve, the nerve-muscle interface and muscle fibre have been implemented. The time dependent ionic properties of the nerve and muscle membranes have been simulated using the Hodgkin-Huxley equations and for the muscle fibre, the implementation of the Huxley sliding filament theory for muscular contraction. The results show that nerve may be considered as a fractal transmission line and that the amplitude of the nerve membrane depolarization is dependent on the dimensions of the fibre. Additionally, simulation of the nerve-muscle interface allows the fractal nerve model to be connected to the muscle fibre model and it is shown that a two sarcomere molecular simulation can pr...

  7. Muscle activity in sprinting: a review.

    Science.gov (United States)

    Howard, Róisín M; Conway, Richard; Harrison, Andrew J

    2018-03-01

    The use of electromyography (EMG) is widely recognised as a valuable tool for enhancing the understanding of performance drivers and potential injury risk in sprinting. The timings of muscle activations relative to running gait cycle phases and the technology used to obtain muscle activation data during sprinting are of particular interest to scientists and coaches. This review examined the main muscles being analysed by surface EMG (sEMG), their activations and timing, and the technologies used to gather sEMG during sprinting. Electronic databases were searched using 'Electromyography' OR 'EMG' AND 'running' OR 'sprinting'. Based on inclusion criteria, 18 articles were selected for review. While sEMG is widely used in biomechanics, relatively few studies have used sEMG in sprinting due to system constraints. The results demonstrated a focus on the leg muscles, with over 70% of the muscles analysed in the upper leg. This is consistent with the use of tethered and data logging EMG systems and many sprints being performed on treadmills. Through the recent advances in wireless EMG technology, an increase in the studies on high velocity movements such as sprinting is expected and this should allow practitioners to perform the analysis in an ecologically valid environment.

  8. Tissue-specific stem cells: Lessons from the skeletal muscle satellite cell

    Science.gov (United States)

    Brack, Andrew S.; Rando, Thomas A.

    2012-01-01

    In 1961, the satellite cell was first identified when electron microscopic examination of skeletal muscle demonstrated a cell wedged between the plasma membrane of the muscle fiber and the basement membrane. In recent years it has been conclusively demonstrated that the satellite cell is the primary cellular source for muscle regeneration and is equipped with the potential to self renew, thus functioning as a bone fide skeletal muscle stem cell (MuSC). As we move past the 50th anniversary of the satellite cell, we take this opportunity to discuss the current state of the art and dissect the unknowns in the MuSC field. PMID:22560074

  9. Recent applications of X-ray microanalysis in muscle pathology

    International Nuclear Information System (INIS)

    Wroblewski, R.; Edstrom, L.

    1984-01-01

    X-ray microanalysis of single muscle fibres visualized in the scanning- and scanning-transmission mode of electron microscopy has been applied to human muscle biopsies to quantify changes of intracellular elements in different muscle disorders. To detect elements representing diffusible ions, cryofixation and cryosectioning was performed and analyses were conducted on freeze-dried cryosections 6μm thick. Changes in the concentration of elements were found to differentiate certain muscular disorders. A large increase in sodium (Na) and chlorine (Cl), and a decrease in potassium (K) was typical of myotubular myopathy, while a moderate increase in Na and Cl was found in central core disease and nemaline myopathy

  10. An Intermediate in the evolution of superfast sonic muscles

    Directory of Open Access Journals (Sweden)

    Mok Hin-Kiu

    2011-11-01

    Full Text Available Abstract Background Intermediate forms in the evolution of new adaptations such as transitions from water to land and the evolution of flight are often poorly understood. Similarly, the evolution of superfast sonic muscles in fishes, often considered the fastest muscles in vertebrates, has been a mystery because slow bladder movement does not generate sound. Slow muscles that stretch the swimbladder and then produce sound during recoil have recently been discovered in ophidiiform fishes. Here we describe the disturbance call (produced when fish are held and sonic mechanism in an unrelated perciform pearl perch (Glaucosomatidae that represents an intermediate condition in the evolution of super-fast sonic muscles. Results The pearl perch disturbance call is a two-part sound produced by a fast sonic muscle that rapidly stretches the bladder and an antagonistic tendon-smooth muscle combination (part 1 causing the tendon and bladder to snap back (part 2 generating a higher-frequency and greater-amplitude pulse. The smooth muscle is confirmed by electron microscopy and protein analysis. To our knowledge smooth muscle attachment to a tendon is unknown in animals. Conclusion The pearl perch, an advanced perciform teleost unrelated to ophidiiform fishes, uses a slow type mechanism to produce the major portion of the sound pulse during recoil, but the swimbladder is stretched by a fast muscle. Similarities between the two unrelated lineages, suggest independent and convergent evolution of sonic muscles and indicate intermediate forms in the evolution of superfast muscles.

  11. Laser therapy of muscle injuries.

    Science.gov (United States)

    Dawood, Munqith S; Al-Salihi, Anam Rasheed; Qasim, Amenah Wala'a

    2013-05-01

    Low-level lasers are used in general therapy and healing process due to their good photo-bio-stimulation effects. In this paper, the effects of diode laser and Nd:YAG laser on the healing process of practically managed skeletal muscle trauma has been successfully studied. Standard impact trauma was induced by using a specially designed mechanical device. The impacted muscle was left for 3 days for complete development of blunt trauma. After that it was irradiated by five laser sessions for 5 days. Two types of lasers were used; 785-nm diode laser and 1.064-nm Nd:YAG laser, both in continuous and pulsed modes. A special electronic circuit was designed and implemented to modulate the diode laser for this purpose. Tissue samples of crushed skeletal muscle have been dissected from the injured irradiated muscle then bio-chemically analyzed for the regeneration of contractile and collagenous proteins using Lowry assay for protein determination and Reddy and Enwemeka assay for hydroxyproline determination. The results showed that both lasers stimulate the regeneration capability of traumatized skeletal muscle. The diode laser in CW and pulsed modes showed better results than the Nd:YAG in accelerating the preservation of the normal tissue content of collagenous and contractile proteins beside controlling the regeneration of non-functional fibrous tissue. This study proved that the healing achieved by the laser treatment was faster than the control group by 15-20 days.

  12. Effect of lack of later support in the masseter muscle

    International Nuclear Information System (INIS)

    Fernandez Lopez, Otton

    2007-01-01

    One of the main complaints during dental consultation has been pain in the zone of the masseter muscle, especially a lack of rear support. None research has published that reveals what has been the relationship between the rear support and histological alterations in muscle mass. Both topics have treated to relate through a process of tooth wear in laboratory animals and produce a lack of rear support. Cuts of the masseter muscles and specimens were subjected to microscopic study of light and electronic. The conclusion has been that by removing the rear support are produced important changes to histological level. (author) [es

  13. Chronic progressive external ophthalmoplegia: II. A qualitative and quantitative electronmicroscopy study of skeletal muscles

    Directory of Open Access Journals (Sweden)

    Elza Dias-Tosta

    1988-06-01

    Full Text Available This study quantifies the maior electron microscopic changes in limb muscle biopsies from 31 out of 34 patients with the syndrome of chronic progressive external ophthalmoplegia. Patients were divided into three clinical groups - A 10 sporadic cases with muscle weakness only; B 9 familial cases with muscle weakness only; C 15 cases with muscle weakness and one or more of the following features: pigmentary retinopathy, cerebellar ataxia, pyramidal signs and peripheral neuropathy. Electron microscopic mitochondrial abnormalities were found in all groups (8 patients from group A, 3 from group B, 14 from group C. Quantitative measurements of certain muscle fibre constituents, using a point-counting technique, revealed decreased myofibril volume-fractions and increased volume-fractions of mitochondria, glycogen and lipid in some biopsies from each group. Mitochondrial volume-fractions correlated positively with lipid content, the proportion of type 1 fibres, and the percentage of fibres with increased oxidative enzyme activity. The three groups defined clinically showed no significant differences in terms of the relative proportions of these measured constituents.

  14. Time-resolved diffraction studies of muscle using synchrotron radiation

    International Nuclear Information System (INIS)

    Harford, Jeffrey; Squire, John

    1997-01-01

    Muscle contraction is one of those biological phenomena that we can all appreciate in our everyday lives. Sometimes it is when we are resting quietly and are aware of our heartbeat. At other times it may be when we are exerting ourselves and become short of breath, or when we exercise for a long period and our muscles start to ache. The way in which muscles produce force has exercised the minds of philosophers and scientists at least since the days of Erasistratus in the third century BC. Nowadays, of course, we know a very great deal about muscle structure, physiology and biochemistry, but we still do not know exactly what the molecular process is that produces movement. An ideal way of probing this process would be to be able to obtain signals from the relevant molecules as they actually go through their normal force-generating routine in an active muscle. The spatial dimensions involved are in the region of 1-50 nm, thus precluding the use of light microscopy, and the time regime is microseconds to milliseconds. Techniques with the appropriate spatial resolution might be electron microscopy and x-ray diffraction, but electron microscopy cannot yet be carried out on living tissue. X-ray diffraction methods can clearly have the right sort of spatial resolution, but what about recording diffraction patterns in the very short times involved (say 1 ms)? It is here that the high flux from synchrotron storage rings comes into its own. Using synchrotron radiation from, say, the SRS at the CCLRC Daresbury Laboratory it is possible to record x-ray diffraction patterns from living muscles in the millisecond time regime and to follow how these diffraction patterns change as the muscles go through typical contraction cycles. Unfortunately, x-ray diffraction is not a direct imaging method; the observed distribution of diffracted intensity needs to be interpreted in some way to give useful information on the spatial relationships of the force-generating molecules. This review

  15. 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

  16. Caveolin-3 is associated with the T-tubules of mature skeletal muscle fibers

    DEFF Research Database (Denmark)

    Ralston, E; Ploug, Thorkil

    1999-01-01

    Caveolae are abundant in skeletal muscle and their coat contains a specific isoform of caveolin, caveolin-3. It has been suggested that during muscle development, caveolin-3 is associated with the T-tubules, but that in adult muscle it is found on the plasma membrane only. We have studied...... the distribution of caveolin-3 in single skeletal muscle fibers from adult rat soleus by confocal immunofluorescence and by immunogold electron microscopy. We found that caveolin-3 occurs at the highest density on the plasma membrane but is also present in the core of the fibers, at the I-band/A-band interface...

  17. Non-Straub type actin from molluscan catch muscle

    Energy Technology Data Exchange (ETDEWEB)

    Shelud' ko, Nikolay S., E-mail: sheludko@stl.ru; Girich, Ulyana V.; Lazarev, Stanislav S.; Vyatchin, Ilya G.

    2016-05-27

    We have developed a method of obtaining natural actin from smooth muscles of the bivalves on the example of the Crenomytilus grayanus catch muscle. The muscles were previously rigorized to prevent a loss of thin filaments during homogenization and washings. Thin filaments were isolated with a low ionic strength solution in the presence of ATP and sodium pyrophosphate. Surface proteins of thin filaments-tropomyosin, troponin, calponin and some minor actin-binding proteins-were dissociated from actin filaments by increasing the ionic strength to 0.6 M KCL. Natural fibrillar actin obtained in that way depolymerizes easily in low ionic strength solutions commonly used for the extraction of Straub-type actin from acetone powder. Purification of natural actin was carried out by the polymerization–depolymerization cycle. The content of inactivated actin remaining in the supernatant is much less than at a similar purification of Straub-type actin. A comparative investigation was performed between the natural mussel actin and the Straub-type rabbit skeletal actin in terms of the key properties of actin: polymerization, activation of Mg-ATPase activity of myosin, and the electron-microscopic structure of actin polymers. -- Highlights: •We developed method of repolymerizable invertebrate smooth muscle actin obtaining. •Our method does not involve use of denaturating agents, which could modify proteins. •Viscosity and polymerization rate of actin, gained that way, is similar to Straub one. •Electron microscopy showed that repolymerized mussel actin is similar to Straub one. •Repolymerized mussel actin has greater ATPase activating capacity, than Straub actin.

  18. 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.

  19. The organization of the Golgi complex and microtubules in skeletal muscle is fiber type-dependent

    DEFF Research Database (Denmark)

    Ralston, E; Lu, Z; Ploug, Thorkil

    1999-01-01

    Skeletal muscle has a nonconventional Golgi complex (GC), the organization of which has been a subject of controversy in the past. We have now examined the distribution of the GC by immunofluorescence and immunogold electron microscopy in whole fibers from different rat muscles, both innervated a...

  20. Compartmentalization of NO signaling cascade in skeletal muscles

    International Nuclear Information System (INIS)

    Buchwalow, Igor B.; Minin, Evgeny A.; Samoilova, Vera E.; Boecker, Werner; Wellner, Maren; Schmitz, Wilhelm; Neumann, Joachim; Punkt, Karla

    2005-01-01

    Skeletal muscle functions regulated by NO are now firmly established. However, the literature on the compartmentalization of NO signaling in myocytes is highly controversial. To address this issue, we examined localization of enzymes engaged in L-arginine-NO-cGMP signaling in the rat quadriceps muscle. Employing immunocytochemical labeling complemented with tyramide signal amplification and electron microscopy, we found NO synthase expressed not only in the sarcolemma, but also along contractile fibers, in the sarcoplasmic reticulum and mitochondria. The expression pattern of NO synthase in myocytes showed striking parallels with the enzymes engaged in L-arginine-NO-cGMP signaling (arginase, phosphodiesterase, and soluble guanylyl cyclase). Our findings are indicative of an autocrine fashion of NO signaling in skeletal muscles at both cellular and subcellular levels, and challenge the notion that the NO generation is restricted to the sarcolemma

  1. Relationship between Human Aging Muscle and Oxidative System Pathway

    Directory of Open Access Journals (Sweden)

    Enrico Doria

    2012-01-01

    Full Text Available Ageing is a complex process that in muscle is usually associated with a decrease in mass, strength, and velocity of contraction. One of the most striking effects of ageing on muscle is known as sarcopenia. This inevitable biological process is characterized by a general decline in the physiological and biochemical functions of the major systems. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS generated by the addition of a single electron to the oxygen molecule. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fibre composition, muscle type, and function.

  2. Decellularized Human Skeletal Muscle as Biologic Scaffold for Reconstructive Surgery

    Directory of Open Access Journals (Sweden)

    Andrea Porzionato

    2015-07-01

    Full Text Available Engineered skeletal muscle tissues have been proposed as potential solutions for volumetric muscle losses, and biologic scaffolds have been obtained by decellularization of animal skeletal muscles. The aim of the present work was to analyse the characteristics of a biologic scaffold obtained by decellularization of human skeletal muscles (also through comparison with rats and rabbits and to evaluate its integration capability in a rabbit model with an abdominal wall defect. Rat, rabbit and human muscle samples were alternatively decellularized with two protocols: n.1, involving sodium deoxycholate and DNase I; n.2, trypsin-EDTA and Triton X-NH4OH. Protocol 2 proved more effective, removing all cellular material and maintaining the three-dimensional networks of collagen and elastic fibers. Ultrastructural analyses with transmission and scanning electron microscopy confirmed the preservation of collagen, elastic fibres, glycosaminoglycans and proteoglycans. Implantation of human scaffolds in rabbits gave good results in terms of integration, although recellularization by muscle cells was not completely achieved. In conclusion, human skeletal muscles may be effectively decellularized to obtain scaffolds preserving the architecture of the extracellular matrix and showing mechanical properties suitable for implantation/integration. Further analyses will be necessary to verify the suitability of these scaffolds for in vitro recolonization by autologous cells before in vivo implantation.

  3. Skeletal muscle repair in a mouse model of nemaline myopathy.

    Science.gov (United States)

    Sanoudou, Despina; Corbett, Mark A; Han, Mei; Ghoddusi, Majid; Nguyen, Mai-Anh T; Vlahovich, Nicole; Hardeman, Edna C; Beggs, Alan H

    2006-09-01

    Nemaline myopathy (NM), the most common non-dystrophic congenital myopathy, is a variably severe neuromuscular disorder for which no effective treatment is available. Although a number of genes have been identified in which mutations can cause NM, the pathogenetic mechanisms leading to the phenotypes are poorly understood. To address this question, we examined gene expression patterns in an NM mouse model carrying the human Met9Arg mutation of alpha-tropomyosin slow (Tpm3). We assessed five different skeletal muscles from affected mice, which are representative of muscles with differing fiber-type compositions, different physiological specializations and variable degrees of pathology. Although these same muscles in non-affected mice showed marked variation in patterns of gene expression, with diaphragm being the most dissimilar, the presence of the mutant protein in nemaline muscles resulted in a more similar pattern of gene expression among the muscles. This result suggests a common process or mechanism operating in nemaline muscles independent of the variable degrees of pathology. Transcriptional and protein expression data indicate the presence of a repair process and possibly delayed maturation in nemaline muscles. Markers indicative of satellite cell number, activated satellite cells and immature fibers including M-Cadherin, MyoD, desmin, Pax7 and Myf6 were elevated by western-blot analysis or immunohistochemistry. Evidence suggesting elevated focal repair was observed in nemaline muscle in electron micrographs. This analysis reveals that NM is characterized by a novel repair feature operating in multiple different muscles.

  4. Helmint eggs elimination performance during lammelar settling and sand filters in Beniel WWTP (Murcia, Spain)

    International Nuclear Information System (INIS)

    Simon Andreu, P. J.; Cardin Mifsut, C.; Pacheco Ballarin, S.; Martinez Muro, M. A.; Vicente Gonzalez, J. A.; Llosar Llacer, C.

    2010-01-01

    With this study, it was observed Ascaris suum eggs elimination yield of tertiary treatment in Beniel wastewater treatment plant (WWTP) in Murcia Region (Spain). It was inoculated a sample of Ascaris suum eggs in the treatment in maximum flow conditions and it was calculated the retention yield of the lamellar settling and sand filters. (Author) 3 refs.

  5. Helmint eggs elimination performance during lammelar settling and sand filters in Beniel WWTP (Murcia, Spain); Rendimiento en la eliminacion de huevos de helminto en la decantacion lamelar y filtracion por arena en la EDAR de Beniel (Murcia)

    Energy Technology Data Exchange (ETDEWEB)

    Simon Andreu, P. J.; Cardin Mifsut, C.; Pacheco Ballarin, S.; Martinez Muro, M. A.; Vicente Gonzalez, J. A.; Llosar Llacer, C.

    2010-07-01

    With this study, it was observed Ascaris suum eggs elimination yield of tertiary treatment in Beniel wastewater treatment plant (WWTP) in Murcia Region (Spain). It was inoculated a sample of Ascaris suum eggs in the treatment in maximum flow conditions and it was calculated the retention yield of the lamellar settling and sand filters. (Author) 3 refs.

  6. Ultrastructural and Energy dispersive analysis of inorganic inclusions in a muscle biopsy

    International Nuclear Information System (INIS)

    Dodson, R.F.; Castillo-Mozun, P.; Hieger, L.R.; Williams, M.G. Jr.

    1981-01-01

    A muscle biopsy that, by light microscopy, exhibited mild atrophy consistent with chronic denervating disease was submitted for ultrastructural analysis. Inorganic structures within the tissue were defined by energy dispersive analysis as aluminosilicates, magnesium silicates, and iron deposits. These structures were localized in the interstitial (intercollagenous) area and in high concentrations within degenerated muscle bundles. An alteration of the blood/muscle barrier has obviously occurred; however, the extent to which the end result commonly occurs in humans is unknown. Clarification of the question raised by this observation will have to be derived from animal studies, and clinicians must have an awareness of the need for electron microscopy/energy-dispersive x-ray analysis in muscle biopsies from patients with similar therapeutic backgrounds

  7. Effects of microgravity on muscle and cerebral cortex: a suggested interaction

    Science.gov (United States)

    D'Amelio, F.; Fox, R. A.; Wu, L. C.; Daunton, N. G.; Corcoran, M. L.

    The ``slow'' antigravity muscle adductor longus was studied in rats after 14 days of spaceflight (SF). The techniques employed included standard methods for light microscopy, neural cell adhesion molecule (N-CAM) immunocytochemistry and electron microscopy. Light and electron microscopy revealed myofiber atrophy, segmental necrosis and regenerative myofibers. Regenerative myofibers were N-CAM immunoreactive (N-CAM-IR). The neuromuscular junctions showed axon terminals with a decrease or absence of synaptic vesicles, degenerative changes, vacant axonal spaces and changes suggestive of axonal sprouting. No alterations of muscle spindles was seen either by light or electron microscopy. These observations suggest that muscle regeneration and denervation and synaptic remodeling at the level of the neuromuscular junction may take place during spaceflight. In a separate study, GABA immunoreactivity (GABA-IR) was evaluated at the level of the hindlimb representation of the rat somatosensory cortex after 14 days of hindlimb unloading by tail suspension (``simulated'' microgravity). A reduction in number of GABA-immunoreactive cells with respect to the control animals was observed in layer Va and Vb. GABA-IR terminals were also reduced in the same layers, particularly those terminals surrounding the soma and apical dendrites of pyramidal cells in layer Vb. On the basis of previous morphological and behavioral studies of the neuromuscular system after spaceflight and hindlimb suspension it is suggested that after limb unloading there are alterations of afferent signaling and feedback information from intramuscular receptors to the cerebral cortex due to modifications in the reflex organization of hindlimb muscle groups. We propose that the changes observed in GABA immunoreactivity of cells and terminals is an expression of changes in their modulatory activity to compensate for the alterations in the afferent information.

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

    Directory of Open Access Journals (Sweden)

    Elizabeth

    2016-03-01

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

  9. Force encoding in muscle spindles during stretch of passive muscle.

    Directory of Open Access Journals (Sweden)

    Kyle P Blum

    2017-09-01

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

  10. Force encoding in muscle spindles during stretch of passive muscle.

    Science.gov (United States)

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

    2017-09-01

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

  11. Effect of magnesium on reactive oxygen species production in the thigh muscles of broiler chickens.

    Science.gov (United States)

    Liu, Y X; Guo, Y M; Wang, Z

    2007-02-01

    1. The objective of the present study was to investigate the effect of magnesium (Mg) on reactive oxygen species (ROS) production in the thigh muscles of broiler chickens. A total of 96 1-d-old male Arbor Acre broiler chickens were randomly allocated into two groups, fed either on low-Mg or control diets containing about 1.2 g/kg or 2.4 g Mg/kg dry matter. 2. The low-Mg diet significantly increased malondialdehyde (MDA) concentration and decreased glutathione (GSH) in the thigh muscles of broiler chickens. ROS production in the thigh muscle homogenate was significantly higher in the low-Mg group than in the control group. Compared with the control, muscle Mg concentration of broiler chickens from the low-Mg group decreased by 9.5%. 3. Complex II and III activities of the mitochondrial electron transport chain in broilers on low-Mg diet increased by 23 and 35%, respectively. Significant negative correlations between ROS production and the activities of mitochondrial electron transport chain (ETC) complexes were observed. 4. The low-Mg diet did not influence contents of iron (Fe) or calcium (Ca) in the thigh muscles of broiler chickens and did not influence unsaturated fatty acid composition (except C18:2) in the thigh muscles. 5. A low-Mg diet decreased Mg concentration in the thigh muscles of broiler chickens and then induced higher activities of mitochondrial ETC, consequently increasing ROS production. These results suggest that Mg modulates the oxidation-anti-oxidation system of the thigh muscles at least partly through affecting ROS production.

  12. 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.

  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. Painful unilateral temporalis muscle enlargement: reactive masticatory muscle hypertrophy.

    Science.gov (United States)

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

    2014-06-01

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

  15. Respiratory muscle training for cystic fibrosis.

    Science.gov (United States)

    Hilton, Nathan; Solis-Moya, Arturo

    2018-05-24

    Cystic fibrosis is the most common autosomal recessive disease in white populations, and causes respiratory dysfunction in the majority of individuals. Numerous types of respiratory muscle training to improve respiratory function and health-related quality of life in people with cystic fibrosis have been reported in the literature. Hence a systematic review of the literature is needed to establish the effectiveness of respiratory muscle training (either inspiratory or expiratory muscle training) on clinical outcomes in cystic fibrosis. This is an update of a previously published review. To determine the effectiveness of respiratory muscle training on clinical outcomes in people with cystic fibrosis. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials register comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of most recent search: 17 April 2018.A hand search of the Journal of Cystic Fibrosis and Pediatric Pulmonology was performed, along with an electronic search of online trial databases up until 07 May 2018. Randomised controlled studies comparing respiratory muscle training with a control group in people with cystic fibrosis. Review authors independently selected articles for inclusion, evaluated the methodological quality of the studies, and extracted data. Additional information was sought from trial authors where necessary. The quality of the evidence was assessed using the GRADE system MAIN RESULTS: Authors identified 19 studies, of which nine studies with 202 participants met the review's inclusion criteria. There was wide variation in the methodological and written quality of the included studies. Four of the nine included studies were published as abstracts only and lacking concise details, thus limiting the information available. Seven studies were parallel studies and two of a cross-over design. Respiratory

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

    Science.gov (United States)

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

    2012-10-01

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

  17. Muscle force depends on the amount of transversal muscle loading.

    Science.gov (United States)

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

    2014-06-03

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

  18. Composition of Muscle Fiber Types in Rat Rotator Cuff Muscles.

    Science.gov (United States)

    Rui, Yongjun; Pan, Feng; Mi, Jingyi

    2016-10-01

    The rat is a suitable model to study human rotator cuff pathology owing to the similarities in morphological anatomy structure. However, few studies have reported the composition muscle fiber types of rotator cuff muscles in the rat. In this study, the myosin heavy chain (MyHC) isoforms were stained by immunofluorescence to show the muscle fiber types composition and distribution in rotator cuff muscles of the rat. It was found that rotator cuff muscles in the rat were of mixed fiber type composition. The majority of rotator cuff fibers labeled positively for MyHCII. Moreover, the rat rotator cuff muscles contained hybrid fibers. So, compared with human rotator cuff muscles composed partly of slow-twitch fibers, the majority of fast-twitch fibers in rat rotator cuff muscles should be considered when the rat model study focus on the pathological process of rotator cuff muscles after injury. Gaining greater insight into muscle fiber types in rotator cuff muscles of the rat may contribute to elucidate the mechanism of pathological change in rotator cuff muscles-related diseases. Anat Rec, 299:1397-1401, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  19. Plastic Muscles TM as lightweight, low voltage actuators and sensors

    Science.gov (United States)

    Bennett, Matthew; Leo, Donald; Duncan, Andrew

    2008-03-01

    Using proprietary technology, Discover Technologies has developed ionomeric polymer transducers that are capable of long-term operation in air. These "Plastic Muscle TM" transducers are useful as soft distributed actuators and sensors and have a wide range of applications in the aerospace, robotics, automotive, electronics, and biomedical industries. Discover Technologies is developing novel fabrication methods that allow the Plastic Muscles TM to be manufactured on a commercial scale. The Plastic Muscle TM transducers are capable of generating more than 0.5% bending strain at a peak strain rate of over 0.1 %/s with a 3 V input. Because the Plastic Muscles TM use an ionic liquid as a replacement solvent for water, they are able to operate in air for long periods of time. Also, the Plastic Muscles TM do not exhibit the characteristic "back relaxation" phenomenon that is common in water-swollen devices. The elastic modulus of the Plastic Muscle TM transducers is estimated to be 200 MPa and the maximum generated stress is estimated to be 1 MPa. Based on these values, the maximum blocked force at the tip of a 6 mm wide, 35 mm long actuator is estimated to be 19 mN. Modeling of the step response with an exponential series reveals nonlinearity in the transducers' behavior.

  20. Skeletal Muscle Magnetic Resonance Imaging of the Lower Limbs in Late-onset Lipid Storage Myopathy with Electron Transfer Flavoprotein Dehydrogenase Gene Mutations

    Institute of Scientific and Technical Information of China (English)

    Xin-Yi Liu; Ming Jin; Zhi-Qiang Wang; Dan-Ni Wang; Jun-Jie He; Min-Ting Lin; Hong-Xia Fu

    2016-01-01

    Background:Lipid storage myopathy (LSM) is a genetically heterogeneous group with variable clinical phenotypes.Late-onset multiple acyl-coenzyme A dehydrogenation deficiency (MADD) is a rather common form of LSM in China.Diagnosis and clinical management of it remain challenging,especially without robust muscle biopsy result and genetic detection.As the noninvasion and convenience,muscle magnetic resonance imaging (MRI) is a helpful assistant,diagnostic tool for neuromuscular disorders.However,the disease-specific MRI patterns of muscle involved and its diagnostic value in late-onset MADD have not been systematic analyzed.Methods:We assessed the MRI pattern and fat infiltration degree of the lower limb muscles in 28 late-onset MADD patients,combined with detailed clinical features and gene spectrum.Fat infiltration degree of the thigh muscle was scored while that ofgluteus was described as obvious or not.Associated muscular atrophy was defined as obvious muscle bulk reduction.Results:The mean scores were significantly different among the anterior,medial,and posterior thigh muscle groups.The mean of fat infiltration scores on posterior thigh muscle group was significantly higher than either anterior or medial thigh muscle group (P < 0.001).Moreover,the mean score on medial thigh muscle group was significantly higher than that of anterior thigh muscle group (P < 0.01).About half of the patients displayed fat infiltration and atrophy in gluteus muscles.Of 28 patients,12 exhibited atrophy in medial and/or posterior thigh muscle groups,especially in posterior thigh muscle group.Muscle edema pattern was not found in all the patients.Conclusions:Late-onset MADD patients show a typical muscular imaging pattern of fat infiltration and atrophy on anterior,posterior,and medial thigh muscle groups,with major involvement of posterior thigh muscle group and gluteus muscles and a sparing involvement of anterior thigh compartment.Our findings also suggest that muscle MRI of

  1. Isolation and characterization of the inositol trisphosphate receptor from smooth muscle

    International Nuclear Information System (INIS)

    Chadwick, C.C.; Saito, A.; Fleischer, S.

    1990-01-01

    The release of Ca 2+ from internal stores is requisite to muscle contraction. In skeletal muscle and heart, the Ca 2+ release channels (ryanodine receptor) of sarcoplasmic reticulum, involved in excitation-contraction coupling, have recently been isolated and characterized. In smooth muscle, inositol 1,4,5-trisphosphate (IP 3 ) is believed to mobilize Ca 2+ from internal stores and thereby modulate contraction. The authors describe the isolation of an IP 3 receptor from smooth muscle. Bovine aorta smooth muscle microsomes were solubilized with 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate, and the IP 3 receptor was purified by sucrose gradient centrifugation and column chromatography with heparin-agarose and wheat germ agglutinin-agarose. The receptor is an oligomer of a single polypeptide with a M r of 224,000 as determined by SDS/PAGE. Negative-staining electron microscopy reveals that the receptor is a large pinwheel-like structure having surface dimensions of ∼250 x 250 angstrom with fourfold symmetry. The IP 3 receptor from smooth muscle is similar to the ryanodine receptor with regard to its large size and fourfold symmetry, albeit distinct with regard to appearance, protomer size, and ligand binding

  2. Stretching skeletal muscle: chronic muscle lengthening through sarcomerogenesis.

    Directory of Open Access Journals (Sweden)

    Alexander M Zöllner

    Full Text Available Skeletal muscle responds to passive overstretch through sarcomerogenesis, the creation and serial deposition of new sarcomere units. Sarcomerogenesis is critical to muscle function: It gradually re-positions the muscle back into its optimal operating regime. Animal models of immobilization, limb lengthening, and tendon transfer have provided significant insight into muscle adaptation in vivo. Yet, to date, there is no mathematical model that allows us to predict how skeletal muscle adapts to mechanical stretch in silico. Here we propose a novel mechanistic model for chronic longitudinal muscle growth in response to passive mechanical stretch. We characterize growth through a single scalar-valued internal variable, the serial sarcomere number. Sarcomerogenesis, the evolution of this variable, is driven by the elastic mechanical stretch. To analyze realistic three-dimensional muscle geometries, we embed our model into a nonlinear finite element framework. In a chronic limb lengthening study with a muscle stretch of 1.14, the model predicts an acute sarcomere lengthening from 3.09[Formula: see text]m to 3.51[Formula: see text]m, and a chronic gradual return to the initial sarcomere length within two weeks. Compared to the experiment, the acute model error was 0.00% by design of the model; the chronic model error was 2.13%, which lies within the rage of the experimental standard deviation. Our model explains, from a mechanistic point of view, why gradual multi-step muscle lengthening is less invasive than single-step lengthening. It also explains regional variations in sarcomere length, shorter close to and longer away from the muscle-tendon interface. Once calibrated with a richer data set, our model may help surgeons to prevent muscle overstretch and make informed decisions about optimal stretch increments, stretch timing, and stretch amplitudes. We anticipate our study to open new avenues in orthopedic and reconstructive surgery and enhance

  3. Sodium Chloride Diffusion during Muscle Salting Evidenced by Energy-Dispersive X-ray Spectroscopy Imaging.

    Science.gov (United States)

    Filgueras, Rénata; Peyrin, Frédéric; Vénien, Annie; Hénot, Jean Marc; Astruc, Thierry

    2016-01-27

    To better understand the relationship between the muscle structure and NaCl transfers in meat, we used energy-dispersive X-ray spectroscopy (EDS) coupled with scanning electron microscopy (SEM) to analyze brined and dry-salted rat muscles. The muscles were freeze-dried to avoid the delocalization of soluble ions that happens in regular dehydration through a graded series of ethanol. Na and Cl maps were superimposed on SEM images to combine the muscle structure and NaCl diffusion. Brining causes rapid diffusion of NaCl through the tissue. Most brine diffuses in a linear front from the muscle surface, but a small proportion enters through the perimysium network. The muscle area penetrated by brine shows heterogeneous patterns of NaCl retention, with some connective tissue islets containing more NaCl than other parts of perimysium. NaCl penetration is considerably slower after dry salting than after brining.

  4. Muscle Bioenergetic Considerations for Intrinsic Laryngeal Skeletal Muscle Physiology

    Science.gov (United States)

    Sandage, Mary J.; Smith, Audrey G.

    2017-01-01

    Purpose: Intrinsic laryngeal skeletal muscle bioenergetics, the means by which muscles produce fuel for muscle metabolism, is an understudied aspect of laryngeal physiology with direct implications for voice habilitation and rehabilitation. The purpose of this review is to describe bioenergetic pathways identified in limb skeletal muscle and…

  5. Mercury speciation and selenium in toothed-whale muscles

    International Nuclear Information System (INIS)

    Sakamoto, Mineshi; Itai, Takaaki; Yasutake, Akira; Iwasaki, Toshihide; Yasunaga, Genta; Fujise, Yoshihiro; Nakamura, Masaaki; Murata, Katsuyuki; Man Chan, Hing; Domingo, José L.; Marumoto, Masumi

    2015-01-01

    Mercury accumulates at high levels in marine mammal tissues. However, its speciation is poorly understood. The main goal of this investigation was to establish the relationships among mercury species and selenium (Se) concentrations in toothed-whale muscles at different mercury levels. The concentrations of total mercury (T-Hg), methylmercury (MeHg), inorganic mercury (I-Hg) and Se were determined in the muscles of four toothed-whale species: bottlenose dolphins (n=31), Risso's dolphins (n=30), striped dolphins (n=29), and short-finned pilot whales (n=30). In each species, the MeHg concentration increased with increasing T-Hg concentration, tending to reach a plateau. In contrast, the proportion of MeHg in T-Hg decreased from 90–100% to 20–40%. The levels of T-Hg and Se showed strong positive correlations. Se/I-Hg molar ratios rapidly decreased with the increase of I-Hg and reached almost 1 in all species. These results suggested that the demethylated MeHg immediately formed Se/I-Hg equimolar complex of mercury selenide (HgSe) in their muscles. In addition, an X-ray absorption fine structure analysis (XAFS) of a bottlenose dolphin muscle confirmed that the dominant chemical form of the Se/I-Hg equimolar complex was HgSe. HgSe was mainly localized in cells near the endomysium using electron probe microanalysis (EPMA). These results suggested that the demethylated MeHg finally deposits within muscle cells of bottlenose dolphin as an inert HgSe. - Highlights: • T-Hg, MeHg, I-Hg and Se were determined in the muscles of four toothed-whales. • MeHg increased with increasing T-Hg and tended to reach a plateau in all species. • Se/I-Hg molar ratios rapidly decreased with increase of I-Hg and reached almost 1. • XAFS of bottlenose dolphin muscle confirmed that HgSe was dominant chemical form. • EPMA of bottlenose dolphin muscle showed that HgSe deposited in muscle cells.

  6. Mercury speciation and selenium in toothed-whale muscles

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Mineshi, E-mail: sakamoto@nimd.go.jp [National Institute for Minamata Disease, Hama 4058-18, Minamata, Kumamoto 867-0008 (Japan); Itai, Takaaki [Ehime University, Bunkyo 2-5, Matsuyama 790-8755 (Japan); Yasutake, Akira [National Institute for Minamata Disease, Hama 4058-18, Minamata, Kumamoto 867-0008 (Japan); Iwasaki, Toshihide [Tohoku National Fisheries Research Institute, 25-259 Shimomekurakubo, Aomori 031-0841 (Japan); Yasunaga, Genta; Fujise, Yoshihiro [Institute of Cetacean Research, 4-5 Toyomi, Tokyo 104-0055 (Japan); Nakamura, Masaaki [National Institute for Minamata Disease, Hama 4058-18, Minamata, Kumamoto 867-0008 (Japan); Murata, Katsuyuki [Akita University School of Medicine, Hondo 1-1-1, Akita 010-8543 (Japan); Man Chan, Hing [University of Ottawa, Marie-Curie, Ottawa, ON, Canada KIN 6N5 (Canada); Domingo, José L. [School of Medicine, IISPV, Universitat “Rovira i Virgili”, Reus (Spain); Marumoto, Masumi [National Institute for Minamata Disease, Hama 4058-18, Minamata, Kumamoto 867-0008 (Japan)

    2015-11-15

    Mercury accumulates at high levels in marine mammal tissues. However, its speciation is poorly understood. The main goal of this investigation was to establish the relationships among mercury species and selenium (Se) concentrations in toothed-whale muscles at different mercury levels. The concentrations of total mercury (T-Hg), methylmercury (MeHg), inorganic mercury (I-Hg) and Se were determined in the muscles of four toothed-whale species: bottlenose dolphins (n=31), Risso's dolphins (n=30), striped dolphins (n=29), and short-finned pilot whales (n=30). In each species, the MeHg concentration increased with increasing T-Hg concentration, tending to reach a plateau. In contrast, the proportion of MeHg in T-Hg decreased from 90–100% to 20–40%. The levels of T-Hg and Se showed strong positive correlations. Se/I-Hg molar ratios rapidly decreased with the increase of I-Hg and reached almost 1 in all species. These results suggested that the demethylated MeHg immediately formed Se/I-Hg equimolar complex of mercury selenide (HgSe) in their muscles. In addition, an X-ray absorption fine structure analysis (XAFS) of a bottlenose dolphin muscle confirmed that the dominant chemical form of the Se/I-Hg equimolar complex was HgSe. HgSe was mainly localized in cells near the endomysium using electron probe microanalysis (EPMA). These results suggested that the demethylated MeHg finally deposits within muscle cells of bottlenose dolphin as an inert HgSe. - Highlights: • T-Hg, MeHg, I-Hg and Se were determined in the muscles of four toothed-whales. • MeHg increased with increasing T-Hg and tended to reach a plateau in all species. • Se/I-Hg molar ratios rapidly decreased with increase of I-Hg and reached almost 1. • XAFS of bottlenose dolphin muscle confirmed that HgSe was dominant chemical form. • EPMA of bottlenose dolphin muscle showed that HgSe deposited in muscle cells.

  7. Apoptosis-inducing effect of selective sensory or motor nerve injury on skeletal muscle atrophy

    Directory of Open Access Journals (Sweden)

    Lei ZHAO

    2011-09-01

    Full Text Available Objective To explore the apoptosis-inducing effect of selective sensory or motor nerve injury on skeletal muscle atrophy.Methods Thirty healthy adult SD rats were randomly divided into three groups,namely,ventral root transection group(VRT group,received left L4-L6 ventral rhizotomy,dorsal root transection group(DRT group,received left L4-L6 dorsal rhizotomy,and sciatic nerve transection group(SNT group,received left sciatic nerve transection.Each group comprised 10 SD rats.The bilateral gastrocnemius was harvested 10 weeks after operation to observe the apoptosis and Fas/FasL expression of the skeletal muscle cells through fluorescent labeling,transmission electron microscopy,and immunohistochemistry.Result Ten weeks after the denervation,apoptosis-related changes,especially obvious changes of the nuclear apoptotic morphology,were observed in the skeletal muscle cells.The aggregation degree of the nucleus and the expression of Fas/FasL increased in the following order: DRT group,VRT group,and SNT group.No apoptotic body,but early apoptotic morphology,was found in the denervated gastrocnemius through transmission electron microscopy.Conclusions The effect of motor nerve injury on skeletal muscle atrophy is more serious than that of sensory nerve injury.The rebuilding of motor nerves should be preferentially considered in the clinical treatment of muscle atrophy induced by denervation.

  8. Effects of oblique muscle surgery on the rectus muscle pulley

    International Nuclear Information System (INIS)

    Okanobu, Hirotaka; Kono, Reika; Ohtsuki, Hiroshi

    2011-01-01

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

  9. Semimembranosus muscle herniation: a rare case with emphasis on muscle biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Naffaa, Lena [American University of Beirut, Department of Diagnostic Radiology, P.O. Box 11-0236, Riad El-Solh, Beirut (Lebanon); Moukaddam, Hicham [Saint Rita Medical Center, Lima, OH (United States); Samim, Mohammad [New York University, Department of Radiology, Hospital for Joint Disease, New York, NY (United States); Lemieux, Aaron [University of California, San Diego School of Medicine, La Jolla, CA (United States); Smitaman, Edward [University of California, San Diego, Teleradiology and Education Center, San Diego, CA (United States)

    2017-03-15

    Muscle herniations are rare and most reported cases involve muscles of the lower leg. We use a case of muscle herniation involving the semimembranosus muscle, presenting as a painful mass in an adolescent male after an unspecified American football injury, to highlight a simple concept of muscle biomechanics as it pertains to muscle hernia(s): decreased traction upon muscle fibers can increase conspicuity of muscle herniation(s) - this allows a better understanding of the apt provocative maneuvers to employ, during dynamic ultrasound or magnetic resonance imaging, in order to maximize diagnostic yield and, thereby, limit patient morbidity related to any muscle herniation. Our patient subsequently underwent successful decompressive fasciotomy and has since returned to his normal daily activities. (orig.)

  10. Semimembranosus muscle herniation: a rare case with emphasis on muscle biomechanics

    International Nuclear Information System (INIS)

    Naffaa, Lena; Moukaddam, Hicham; Samim, Mohammad; Lemieux, Aaron; Smitaman, Edward

    2017-01-01

    Muscle herniations are rare and most reported cases involve muscles of the lower leg. We use a case of muscle herniation involving the semimembranosus muscle, presenting as a painful mass in an adolescent male after an unspecified American football injury, to highlight a simple concept of muscle biomechanics as it pertains to muscle hernia(s): decreased traction upon muscle fibers can increase conspicuity of muscle herniation(s) - this allows a better understanding of the apt provocative maneuvers to employ, during dynamic ultrasound or magnetic resonance imaging, in order to maximize diagnostic yield and, thereby, limit patient morbidity related to any muscle herniation. Our patient subsequently underwent successful decompressive fasciotomy and has since returned to his normal daily activities. (orig.)

  11. Muscle Contraction.

    Science.gov (United States)

    Sweeney, H Lee; Hammers, David W

    2018-02-01

    SUMMARYMuscle cells are designed to generate force and movement. There are three types of mammalian muscles-skeletal, cardiac, and smooth. Skeletal muscles are attached to bones and move them relative to each other. Cardiac muscle comprises the heart, which pumps blood through the vasculature. Skeletal and cardiac muscles are known as striated muscles, because the filaments of actin and myosin that power their contraction are organized into repeating arrays, called sarcomeres, that have a striated microscopic appearance. Smooth muscle does not contain sarcomeres but uses the contraction of filaments of actin and myosin to constrict blood vessels and move the contents of hollow organs in the body. Here, we review the principal molecular organization of the three types of muscle and their contractile regulation through signaling mechanisms and discuss their major structural and functional similarities that hint at the possible evolutionary relationships between the cell types. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

  12. Pre-mRNA Processing Is Partially Impaired in Satellite Cell Nuclei from Aged Muscles

    Directory of Open Access Journals (Sweden)

    Manuela Malatesta

    2010-01-01

    Full Text Available Satellite cells are responsible for the capacity of mature mammalian skeletal muscles to repair and maintain mass. During aging, skeletal muscle mass as well as the muscle strength and endurance progressively decrease, leading to a condition termed sarcopenia. The causes of sarcopenia are manifold and remain to be completely elucidated. One of them could be the remarkable decline in the efficiency of muscle regeneration; this has been associated with decreasing amounts of satellite cells, but also to alterations in their activation, proliferation, and/or differentiation. In this study, we investigated the satellite cell nuclei of biceps and quadriceps muscles from adult and old rats; morphometry and immunocytochemistry at light and electron microscopy have been combined to assess the organization of the nuclear RNP structural constituents involved in different steps of mRNA formation. We demonstrated that in satellite cells the RNA pathways undergo alterations during aging, possibly hampering their responsiveness to muscle damage.

  13. A statistical model for predicting muscle performance

    Science.gov (United States)

    Byerly, Diane Leslie De Caix

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

  14. Pneumatic Artificial Muscles Based on Biomechanical Characteristics of Human Muscles

    Directory of Open Access Journals (Sweden)

    N. Saga

    2006-01-01

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

  15. PGC-1α is dispensable for exercise-induced mitochondrial biogenesis in skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Glenn C Rowe

    Full Text Available Exercise confers numerous health benefits, many of which are thought to stem from exercise-induced mitochondrial biogenesis (EIMB in skeletal muscle. The transcriptional coactivator PGC-1α, a potent regulator of metabolism in numerous tissues, is widely believed to be required for EIMB. We show here that this is not the case. Mice engineered to lack PGC-1α specifically in skeletal muscle (Myo-PGC-1αKO mice retained intact EIMB. The exercise capacity of these mice was comparable to littermate controls. Induction of metabolic genes after 2 weeks of in-cage voluntary wheel running was intact. Electron microscopy revealed no gross abnormalities in mitochondria, and the mitochondrial biogenic response to endurance exercise was as robust in Myo-PGC-1αKO mice as in wildtype mice. The induction of enzymatic activity of the electron transport chain by exercise was likewise unperturbed in Myo-PGC-1αKO mice. These data demonstrate that PGC-1α is dispensable for exercise-induced mitochondrial biogenesis in skeletal muscle, in sharp contrast to the prevalent assumption in the field.

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

    Science.gov (United States)

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

    1998-08-01

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

  17. Muscle Cramps

    Science.gov (United States)

    ... Talk to your provider about the risks and benefits of medicines. How can I prevent muscle cramps? To prevent muscle cramps, you can Stretch your muscles, especially before exercising. If you often get leg cramps at night, ...

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

    Directory of Open Access Journals (Sweden)

    Zielinska M

    2011-12-01

    Full Text Available Marlena Zielinska1,2, Ewa Sawosz1, Marta Grodzik1, Mateusz Wierzbicki1, Maria Gromadka1, Anna Hotowy3, Filip Sawosz3, Andrzej Lozicki1, Andrè Chwalibog31Division of Biotechnology and Biochemistry of Nutrition, Warsaw University of Life sciences, Warsaw, 2The Kielanowski Institute of Animal Physiology and Nutrition, Jablonna, Poland; 3Department of Basic Animal and Veterinary sciences, University of copenhagen, Frederiksberg, DenmarkPurpose: It was hypothesized that heparan sulfate (HS as an essential compound for myogenesis and nanoparticles of gold (nano-Au as highly reactive compounds can affect muscle development as a consequence of molecular regulation of muscle cell formation, and that these effects may be enhanced by a complex of HS conjugated with nano-Au. The objective of the present study was to determine the effect of administration of nano-Au, HS, and a nano-Au+HS complex on the morphological and molecular characteristics of breast muscle during embryogenesis.Methods: Chicken embryos were used as in vivo model. Fertilized chicken eggs (n = 350 were randomly divided into the control group and the groups treated with nano-Au, HS, and nano-Au+HS. The experimental solutions were given in ovo on the first day of incubation and the embryos were evaluated on day 20 of incubation. The methods included biochemical indi- ces in blood, immunohistochemistry, microscopy (transmission electron microscopy, scanning electron microscopy, confocal, and gene expression at the messenger ribonucleic acid and protein levels.Results: The treatments did not adversely affect mortality, organ weight, and homeostasis of the embryos. HS stimulated the development and maturation of breast muscle by increasing the number of nuclei, satellite cells, and muscle fibers and affected the expression of basic fibroblast growth factor-2 and paired-box transcription factor-7. Furthermore, the nano-Au+HS complex contributed to the increased number of myocytes and nuclei in

  19. Nutritional strategies of physically active subjects with muscle dysmorphia.

    Science.gov (United States)

    Contesini, Nadir; Adami, Fernando; Blake, Márcia de-Toledo; Monteiro, Carlos Bm; Abreu, Luiz C; Valenti, Vitor E; Almeida, Fernando S; Luciano, Alexandre P; Cardoso, Marco A; Benedet, Jucemar; de Assis Guedes de Vasconcelos, Francisco; Leone, Claudio; Frainer, Deivis Elton Schlickmann

    2013-05-26

    The aim of this study was to identify dietary strategies for physically active individuals with muscle dysmorphia based on a systematic literature review. References were included if the study population consisted of adults over 18 years old who were physically active in fitness centers. We identified reports through an electronic search ofScielo, Lilacs and Medline using the following keywords: muscle dysmorphia, vigorexia, distorted body image, and exercise. We found eight articles in Scielo, 17 in Medline and 12 in Lilacs. Among the total number of 37 articles, only 17 were eligible for inclusion in this review. The results indicated that the feeding strategies used by physically active individuals with muscle dysmorphia did not include planning or the supervision of a nutritionist. Diet included high protein and low fat foods and the ingestion of dietary and ergogenic supplements to reduce weight. Physically active subjects with muscle dysmorphia could benefit from the help of nutritional professionals to evaluate energy estimation, guide the diet and its distribution in macronutrient and consider the principle of nutrition to functional recovery of the digestive process, promote liver detoxification, balance and guide to organic adequate intake of supplemental nutrients and other substances.

  20. Disinfection of sludge and waste-water by irradiation with electrons of low accelerating voltage

    International Nuclear Information System (INIS)

    Holl, P.; Schneider, H.

    1975-01-01

    From the point of view of hygiene, sewage sludge and water accumulating in ever increasing quantities, some of which is used in agriculture, represent a potential threat to the health of man and beast, as well as to the environment. It is known that these chains of infection can be broken up by ionizing radiation. The use of natural ionizing radiation or electron radiation with high accelerating voltage has not been accepted in practice because the radiation cannot be cut off and the investment cost for electron accelerators with an accelerating voltage of more than 1 MV is very high. These disadvantages may be overcome by using an electron accelerator with low accelerating voltage. Complex experiments have shown that it is not necessary to adapt the thickness of sewage sludge or water layer to the range of electrons. The layer to be irradiated may be much thicker if the substrate is revolved during irradiation. The advantages of this method are low accelerating voltage for the electrons and hence less costly radiation shielding, complete absorption of the radiated energy by the substrate, and low investment and operating cost. The sterilizing effect of the process can be explained by the secondary reactions that take place in the water, in addition to the primary reactions, when irradiating with high specific ionizing density. It is known from experiments carried out by Muenzner that water irradiated with electrons of high specific ionization density, when added to bacterial cultures, will destroy them. This is explained by the Weiss radical theory of water, with reaction products such as H 2 , O 2 and H 2 O 2 . The success of this process is shown by experiments with Escherichia coli, tap water to which Salmonella senftenberg were added, and by the content of Enterobacteriaceae in various sludges as a function of the irradiation period, as well as by the rate at which various invariable species of strongilide larvae, eggs of Ascaris suum, Fasciola hepatica and

  1. The destruction of parasitic resistant stages in sewage sludge by irradiation with low accelerating voltage electrons

    International Nuclear Information System (INIS)

    Enigk, K.; Holl, P.; Dey-Hazra, A.; Polymer-Physik G.m.b.H. und Co. K.G., Tuebingen

    1975-01-01

    The destroying effect of ionizing radiation on parasitic resistant stages in sludge has been tested. Suitable for that process is an electron beam accelerator which will be provided with energy from the electric power supply network which can be switched on and off according to the requirements. Such modern utilities have an enormous beam capacity and a high operating safety. The process is working according to the continuous flow principle and at room temperature. In a series of 13 experiments the effect of different doses has been tested. A dose of 480 kRad (accelerating voltage: 400 kV, beam current: 10 mA , irradiation time: 24 sec.) can easily obtained in practical work and is economically acceptable. By these means approximately 97% of the following parasitic stages have been destroyed: undeveloped eggs of Ascaris suum, Trichuris suis, Fasciola hepatica and gastrointestinal strongylids of pigs, embryonated eggs of Capillaria obsignata and probably of Taenia spec. A few third-stage larvae of Oesophagostomum (Strongylidae) of pigs survived even 108 sec of irradiation; however, they did not develop to maturity in the definitive host. Approximately 25% of the sporulated oocysts of Eimeria tenella were still infective after 108 sec of irradiation. (orig.) [de

  2. Activation of respiratory muscles during respiratory muscle training.

    Science.gov (United States)

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

    2018-01-01

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

  3. Muscle cooling delays activation of the muscle metaboreflex in humans.

    Science.gov (United States)

    Ray, C A; Hume, K M; Gracey, K H; Mahoney, E T

    1997-11-01

    Elevation of muscle temperature has been shown to increase muscle sympathetic nerve activity (MSNA) during isometric exercise in humans. The purpose of the present study was to evaluate the effect of muscle cooling on MSNA responses during exercise. Eight subjects performed ischemic isometric handgrip at 30% of maximal voluntary contraction to fatigue followed by 2 min of postexercise muscle ischemia (PEMI), with and without local cooling of the forearm. Local cooling of the forearm decreased forearm muscle temperature from 31.8 +/- 0.4 to 23.1 +/- 0.8 degrees C (P = 0.001). Time to fatigue was not different during the control and cold trials (156 +/- 11 and 154 +/- 5 s, respectively). Arterial pressures and heart rate were not significantly affected by muscle cooling during exercise, although heart rate tended to be higher during the second minute of exercise (P = 0.053) during muscle cooling. Exercise-induced increases in MSNA were delayed during handgrip with local cooling compared with control. However, MSNA responses at fatigue and PEMI were not different between the two conditions. These findings suggest that muscle cooling delayed the activation of the muscle metaboreflex during ischemic isometric exercise but did not prevent its full expression during fatiguing contraction. These results support the concept that muscle temperature can play a role in the regulation of MSNA during exercise.

  4. Comparative decline of the protein profiles of nebulin in response to denervation in skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jih-Hua [Department of Internal Medicine, Min-Sheng General Hospital, Taoyuan, Taiwan (China); Chang, Nen-Chung [Division of Cardiology, Department of Internal Medicine, College of Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Chen, Sy-Ping [Department of Nursing, Chang Gung University of Science and Technology, Taoyuan, Taiwan (China); Geraldine, Pitchairaj [Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu (India); Jayakumar, Thanasekaran, E-mail: tjaya_2002@yahoo.co.in [Department of Pharmacology and Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Fong, Tsorng-Harn, E-mail: thfong@tmu.edu.tw [Department of Anatomy and Cell Biology, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2015-10-09

    The sliding filament model of the sarcomere was developed more than half a century ago. This model, consisting only of thin and thick filaments, has been efficacious in elucidating many, but not all, features of skeletal muscle. Work during the 1980s revealed the existence of two additional filaments: the giant filamentous proteins titin and nebulin. Nebulin, a giant myofibrillar protein, acts as a protein ruler to maintain the lattice arrays of thin filaments and plays a role in signal transduction and contractile regulation. However, the change of nebulin and its effect on thin filaments in denervation-induced atrophic muscle remains unclear. The purpose of this study is to examine the content and pattern of nebulin, myosin heavy chain (MHC), actin, and titin in innervated and denervated tibialis anterior (TA) muscles of rats using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), densitometry and electron microscopic (EM) analyses. The results revealed that denervation induced muscle atrophy is accompanied by decreased nebulin content in a time-dependent manner. For instant, the levels of nebulin in denervated muscles were markedly (P < 0.05) decreased, about 24.6% and 40.2% in comparison with innervated muscle after denervation of 28 and 56 days, respectively. The nebulin/MHC, nebulin/actin, and nebulin/titin ratios were decreased, suggesting a concomitant reduction of nebulin in denervated muscle. Moreover, a western blotting assay proved that nebulin declined faster than titin on 28 and 56 days of denervated muscle. In addition, EM study revealed that the disturbed arrangements of myofilaments and a disorganized contractile apparatus were also observed in denervated muscle. Overall, the present study provides evidence that nebulin is more sensitive to the effect of denervation than MHC, actin, and titin. Nebulin decline indeed resulted in disintegrate of thin filaments and shortening of sarcomeres. - Highlights: • We successfully

  5. Associations of passive muscle stiffness, muscle stretch tolerance, and muscle slack angle with range of motion: individual and sex differences.

    Science.gov (United States)

    Miyamoto, Naokazu; Hirata, Kosuke; Miyamoto-Mikami, Eri; Yasuda, Osamu; Kanehisa, Hiroaki

    2018-05-29

    Joint range of motion (ROM) is an important parameter for athletic performance and muscular injury risk. Nonetheless, a complete description of muscular factors influencing ROM among individuals and between men and women is lacking. We examined whether passive muscle stiffness (evaluated by angle-specific muscle shear modulus), tolerance to muscle stretch (evaluated by muscle shear modulus at end-ROM), and muscle slack angle of the triceps surae are associated with the individual variability and sex difference in dorsiflexion ROM, using ultrasound shear wave elastography. For men, ROM was negatively correlated to passive muscle stiffness of the medial and lateral gastrocnemius in a tensioned state and positively to tolerance to muscle stretch in the medial gastrocnemius. For women, ROM was only positively correlated to tolerance to muscle stretch in all muscles but not correlated to passive muscle stiffness. Muscle slack angle was not correlated to ROM in men and women. Significant sex differences were observed only for dorsiflexion ROM and passive muscle stiffness in a tensioned state. These findings suggest that muscular factors associated with ROM are different between men and women. Furthermore, the sex difference in dorsiflexion ROM might be attributed partly to that in passive muscle stiffness of plantar flexors.

  6. Age-Associated Impairments in Mitochondrial ADP Sensitivity Contribute to Redox Stress in Senescent Human Skeletal Muscle

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    Graham P. Holloway

    2018-03-01

    Full Text Available Summary: It remains unknown if mitochondrial bioenergetics are altered with aging in humans. We established an in vitro method to simultaneously determine mitochondrial respiration and H2O2 emission in skeletal muscle tissue across a range of biologically relevant ADP concentrations. Using this approach, we provide evidence that, although the capacity for mitochondrial H2O2 emission is not increased with aging, mitochondrial ADP sensitivity is impaired. This resulted in an increase in mitochondrial H2O2 and the fraction of electron leak to H2O2, in the presence of virtually all ADP concentrations examined. Moreover, although prolonged resistance training in older individuals increased muscle mass, strength, and maximal mitochondrial respiration, exercise training did not alter H2O2 emission rates in the presence of ADP, the fraction of electron leak to H2O2, or the redox state of the muscle. These data establish that a reduction in mitochondrial ADP sensitivity increases mitochondrial H2O2 emission and contributes to age-associated redox stress. : Holloway et al. show that an inability of ADP to decrease mitochondrial reactive oxygen species emission contributes to redox stress in skeletal muscle tissue of older individuals and that this process is not recovered following prolonged resistance-type exercise training, despite the general benefits of resistance training for muscle health. Keywords: mitochondria, aging, muscle, ROS, H2O2, ADP, respiration, bioenergetics, exercise, resistance training

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

    Science.gov (United States)

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

    2008-01-01

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

  8. MUSCLE DISORDERS IN ADOLESCENT IDIOPATHIC SCOLIOSIS: LITERATURE REVIEW

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    Débora Pinheiro Lédio Alves

    2016-03-01

    Full Text Available ABSTRACT Scoliosis is characterized by three-dimensional changes of the spine and is estimated to be present in 4% of the population worldwide. The most common form is the adolescent idiopathic. The purpose of this study is to identify the major muscle abnormalities found in patients with adolescent idiopathic scoliosis through a literature review. We conducted an electronic search of the national databases PubMed, Lilacs, PEDro, and EMBASE using the keywords "scoliosis", "biomechanics", "exercise", "physical therapy specialty", "idiopathic", and "muscles", from January 2003 to April 2015. The most relevant articles in English, Portuguese and Spanish were selected by title and abstract. It was also performed a manual search of the references of the selected articles. From a total of 4,319 articles, 11 were selected. We conclude that individuals with AIS have changes in the paraspinal muscles, with a difference in activation between the concave and convex sides, suggesting an increase in EMG activity on the convex side, although there is still no consensus among the authors.

  9. Muscle enzyme release does not predict muscle function impairment after triathlon.

    Science.gov (United States)

    Margaritis, I; Tessier, F; Verdera, F; Bermon, S; Marconnet, P

    1999-06-01

    We sought to determine the effects of a long distance triathlon (4 km swim, 120 km bike-ride, and 30 km run) on the four-day kinetics of the biochemical markers of muscle damage, and whether they were quantitatively linked with muscle function impairment and soreness. Data were collected from 2 days before until 4 days after the completion of the race. Twelve triathletes performed the triathlon and five did not. Maximal voluntary contraction (MVC), muscle soreness (DOMS) and total serum CK, CK-MB, LDH, AST and ALT activities were assessed. Significant changes after triathlon completion were found for all muscle damage indirect markers over time (p triathlon. Long distance triathlon race caused muscle damage, but extent, as well as muscle recovery cannot be evaluated by the magnitude of changes in serum enzyme activities. Muscle enzyme release cannot be used to predict the magnitude of the muscle function impairment caused by muscle damage.

  10. Productive infection of human skeletal muscle cells by pandemic and seasonal influenza A(H1N1 viruses.

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    Marion Desdouits

    Full Text Available Besides the classical respiratory and systemic symptoms, unusual complications of influenza A infection in humans involve the skeletal muscles. Numerous cases of acute myopathy and/or rhabdomyolysis have been reported, particularly following the outbreak of pandemic influenza A(H1N1 in 2009. The pathogenesis of these influenza-associated myopathies (IAM remains unkown, although the direct infection of muscle cells is suspected. Here, we studied the susceptibility of cultured human primary muscle cells to a 2009 pandemic and a 2008 seasonal influenza A(H1N1 isolate. Using cells from different donors, we found that differentiated muscle cells (i. e. myotubes were highly susceptible to infection by both influenza A(H1N1 isolates, whereas undifferentiated cells (i. e. myoblasts were partially resistant. The receptors for influenza viruses, α2-6 and α2-3 linked sialic acids, were detected on the surface of myotubes and myoblasts. Time line of viral nucleoprotein (NP expression and nuclear export showed that the first steps of the viral replication cycle could take place in muscle cells. Infected myotubes and myoblasts exhibited budding virions and nuclear inclusions as observed by transmission electron microscopy and correlative light and electron microscopy. Myotubes, but not myoblasts, yielded infectious virus progeny that could further infect naive muscle cells after proteolytic treatment. Infection led to a cytopathic effect with the lysis of muscle cells, as characterized by the release of lactate dehydrogenase. The secretion of proinflammatory cytokines by muscle cells was not affected following infection. Our results are compatible with the hypothesis of a direct muscle infection causing rhabdomyolysis in IAM patients.

  11. Review of primary spaceflight-induced and secondary reloading-induced changes in slow antigravity muscles of rats

    Science.gov (United States)

    Riley, D. A.

    We have examined the light and electron microscopic properties of hindlimb muscles of rats flown in space for 1-2 weeks on Cosmos biosatellite flights 1887 and 2044 and Space Shuttle missions Spacelab-3, Spacelab Life Sciences-1 and Spacelab Life Sciences-2. Tissues were obtained both inflight and postflight permitting definition of primary microgravity-induced changes and secondary reentry and gravity reloading-induced alterations. Spaceflight causes atrophy and expression of fast fiber characteristics in slow antigravity muscles. The stresses of reentry and reloading reveal that atrophic muscles show increased susceptibility to interstitial edema and ischemic-anoxic necrosis as well as muscle fiber tearing with disruption of contractile proteins. These results demonstrate that the effects of spaceflight on skeletal muscle are multifaceted, and major changes occur both inflight and following return to Earth's gravity.

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

    Science.gov (United States)

    Fuoco, Claudia; Cannata, Stefano; Gargioli, Cesare

    2016-05-01

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

  13. Influence of muscle geometry on shortening speed of fibre, aponeurosis and muscle

    NARCIS (Netherlands)

    Zuurbier, C. J.; Huijing, P. A.

    1992-01-01

    The influence of muscle geometry on muscle shortening of the gastrocnemius medialis muscle (GM) of the rat was studied. Using cinematography, GM geometry was studied during isokinetic concentric activity at muscle lengths ranging from 85 to 105% of the optimum muscle length. The shortening speed of

  14. The structure of the actin-smooth muscle myosin motor domain complex in the rigor state.

    Science.gov (United States)

    Banerjee, Chaity; Hu, Zhongjun; Huang, Zhong; Warrington, J Anthony; Taylor, Dianne W; Trybus, Kathleen M; Lowey, Susan; Taylor, Kenneth A

    2017-12-01

    Myosin-based motility utilizes catalysis of ATP to drive the relative sliding of F-actin and myosin. The earliest detailed model based on cryo-electron microscopy (cryoEM) and X-ray crystallography postulated that higher actin affinity and lever arm movement were coupled to closure of a feature of the myosin head dubbed the actin-binding cleft. Several studies since then using crystallography of myosin-V and cryoEM structures of F-actin bound myosin-I, -II and -V have provided details of this model. The smooth muscle myosin II interaction with F-actin may differ from those for striated and non-muscle myosin II due in part to different lengths of important surface loops. Here we report a ∼6 Å resolution reconstruction of F-actin decorated with the nucleotide-free recombinant smooth muscle myosin-II motor domain (MD) from images recorded using a direct electron detector. Resolution is highest for F-actin and the actin-myosin interface (3.5-4 Å) and lowest (∼6-7 Å) for those parts of the MD at the highest radius. Atomic models built into the F-actin density are quite comparable to those previously reported for rabbit muscle actin and show density from the bound ADP. The atomic model of the MD, is quite similar to a recently published structure of vertebrate non-muscle myosin II bound to F-actin and a crystal structure of nucleotide free myosin-V. Larger differences are observed when compared to the cryoEM structure of F-actin decorated with rabbit skeletal muscle myosin subfragment 1. The differences suggest less closure of the 50 kDa domain in the actin bound skeletal muscle myosin structure. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Identification of cDNA clones expressing immunodiagnostic antigens from Trichinella spiralis

    International Nuclear Information System (INIS)

    Zarlenga, D.; Gamble, H.R.

    1987-01-01

    A cDNA expression library was built in lambda gt11 phage using poly A mRNA isolated from Trichinella spiralis muscle stage larvae. This library was screened with rabbit antibodies to parasite excretory-secretory (ES) products and greater than 180 clones were isolated. Thirteen clones producing highly immunogenic protein antigens were plaque purified and rescreened with pig antisera to T.spiralis, Trichuris suis or Ascaris suum to identify clones producing epitopes specific to T.spiralis ES products, only. Two clones, TsAc-2 and TsAc-8, which displayed strong interactions with pig antisera to T. spiralis were lysogenized in E. coli Y1089 and the protein extracted. Western blots of the crude fusion proteins revealed molecular weights of 133 kD and 129 kD, respectively. Northern blot analysis of total RNA with 32 P labelled cDNA:lambda gt11 probes indicated single RNA transcripts for each clone with molecular sizes corresponding to 800-850 nucleotides. dscDNA inserts were estimated by southern blot analysis to be 500 bp and 340 bp, respectively, with no cross-hybridization observed between the cloned sequences. Dot blots using pig sera to screen crude fusion protein preparations, total bacterial protein (negative controls) and crude worm extract or ES products from T.spiralis, T.suis and A.suum (positive controls) corroborated the specificity and sensitivity of these clones as potential diagnostic antigens for swine trichinellosis

  16. Effect of the bendiocarb on the ultrastructure of rabbit skeletal muscle

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    Katarína Holovská

    2017-01-01

    Full Text Available Bendiocarb belongs to the group of carbamate insecticides that inhibit acetylcholinesterase. In agriculture, it is used to control a variety of insects, therefore it is important to examine every potential aspect of its toxicology. The aim of this study was to observe the effect of bendiocarb on the ultrastructure of the skeletal muscle in rabbits. Rabbits in all experimental groups received capsules of bendiocarb (96% Bendiocarb, Bayer, Germany per os daily at a dose of 5 mg/kg body weight. Samples of skeletal muscles were collected on days 10 and 20. On day 10 of the experiment, muscle fibres were not affected consistently. The observed changes were moderate and focal. Electron microscopy revealed dilatation of sarcoplasmic reticulum, and myofilament disorganization. On day 20 of the experiment, the ultrastructural changes in muscle fibres were more intense and more frequent. The most important alteration was the disruption of the sarcomeres due to the lysis of both thick and thin myofilaments. However, in the unchanged regions of muscle fibres a prominent mitochondrial swelling was observed. Many mitochondria lacked cristae and thus appeared as large membrane-bound cytoplasmic vesicles. The results presented in this study indicate that bendiocarb affects the ultrastructure of skeletal muscles. The intensity of damage (dissolution of myofilaments and disruption of sarcomeres was related to the duration of administration of bendiocarb.

  17. [Morphological signs of mitochondrial cytopathy in skeletal muscles and micro-vessel walls in a patient with cerebral artery dissection associated with MELAS syndrome].

    Science.gov (United States)

    Sakharova, A V; Kalashnikova, L A; Chaĭkovskaia, R P; Mir-Kasimov, M F; Nazarova, M A; Pykhtina, T N; Dobrynina, L A; Patrusheva, N L; Patrushev, L I; Protskiĭ, S V

    2012-01-01

    Skin and muscles biopsy specimens of a patient harboring A3243G mutation in mitochondrial DNA, with dissection of internal carotid and vertebral arteries, associated with MELAS were studied using histochemical and electron-microscopy techniques. Ragged red fibers, regional variability of SDH histochemical reaction, two types of morphologically atypical mitochondria and their aggregation were found in muscle. There was correlation between SDH histochemical staining and number of mitochondria revealed by electron microscopy in muscle tissue. Similar mitochondrial abnormality, their distribution and cell lesions followed by extra-cellular matrix mineralization were found in the blood vessel walls. In line with generalization of cytopathy process caused by gene mutation it can be supposed that changes found in skin and muscle microvessels also exist in large cerebral vessels causing the vessel wall "weakness", predisposing them to dissection.

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

    Science.gov (United States)

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

    2017-01-01

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

  19. [Women boxing athletes' EMG of upper limbs and lumbar muscles in the training of air striking of straight punch].

    Science.gov (United States)

    Zhang, Ri-Hui; Kang, Zhi-Xin

    2011-05-01

    To study training effect of upper limbs and lumbar muscles in the proceed of air striking of straight punch by analyzing boxing athletes' changes of electromyogram (EMG). We measured EMG of ten women boxing athletes' upper arm biceps (contractor muscle), upper arm triceps (antagonistic muscle), forearm flexor muscle (contractor muscle), forearm extensor muscle (antagonistic muscle), and lumbar muscles by ME6000 (Mega Electronics Ltd.). The stipulated exercise was to do air striking of straight punch with loads of 2.5 kg of dumbbell in the hand until exhausted. In the proceed of exercise-induce exhausted, the descend magnitude and speed of median frequency (MF) in upper limb antagonistic muscle exceeded to contracting muscle, moreover, the work percentage showed that contractor have done a larger percentage of work than antagonistic muscle. Compared with world champion's EMG, the majority of ordinary athletes' lumbar muscles MF revealed non-drop tendency, and the work percentage showed that lumbar muscles had a very little percentage of work. After comparing the EMG test index in upper limb and lumbar muscle of average boxing athletes with that of the world champion, we find the testees lack of the training of upper limb antagonistic muscle and lumbar muscle, and more trainings aimed at these muscles need to be taken.

  20. The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days local muscle unloading.

    Science.gov (United States)

    Weber, Tobias; Ducos, Michel; Mulder, Edwin; Beijer, Åsa; Herrera, Frankyn; Zange, Jochen; Degens, Hans; Bloch, Wilhelm; Rittweger, Jörn

    2014-05-01

    In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (Pflow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  1. Muscle oxygenation and fascicle length during passive muscle stretching in ballet-trained subjects.

    Science.gov (United States)

    Otsuki, A; Fujita, E; Ikegawa, S; Kuno-Mizumura, M

    2011-07-01

    Muscle stretching transiently decreases muscle-blood flow corresponding to a muscle extension. It may disturb a balance between muscular oxygen demand and oxygen supply to muscles and reduce muscle oxygenation. However, muscle-stretching training may improve blood circulatory condition, resulting in the maintained muscle oxygenation during muscle stretching. The aim of this study was to investigate changes in muscle-blood volume (tHb) and tissue oxygenation index (TOI) during muscle stretching determined by using near-infrared spectroscopy (NIRS) in ballet-trained (BT) and untrained (C) subjects. 11 BT women who regularly perform muscle stretching and 11 C women participated in this study. Fascicle lengths, tHb and TOI in the tibialis anterior muscle were measured during passive plantar flexion from ankle joint angles of 120° (baseline) to 140°, 160°, the maximal comfortable position without pain (CP), and the maximal position (MP). At 160°, the % fascicle-length change from baseline was significantly lower in the BT than the C group, however, for the changes in tHb and TOI the significant interaction effect between the 2 groups was not detected. On the other hand, although the increases in the fascicle length from baseline to CP and MP were greater in BT than C, the tHb and TOI reductions were comparable between groups. We concluded that it appears that BT can extend their muscles without excessive reduction in muscle-blood volume and muscle oxygenation at relatively same but absolutely greater muscle-stretching levels than C. The attenuation in these indices during high-level muscle stretching may be associated with the repetitive muscle stretching of long-term ballet training. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Composition, Architecture, and Functional Implications of the Connective Tissue Network of the Extraocular Muscles

    Science.gov (United States)

    McLoon, Linda K.; Vicente, André; Fitzpatrick, Krysta R.; Lindström, Mona

    2018-01-01

    Purpose We examined the pattern and extent of connective tissue distribution in the extraocular muscles (EOMs) and determined the ability of the interconnected connective tissues to disseminate force laterally. Methods Human EOMs were examined for collagens I, III, IV, and VI; fibronectin; laminin; and elastin using immunohistochemistry. Connective tissue distribution was examined with scanning electron microscopy. Rabbit EOMs were examined for levels of force transmission longitudinally and transversely using in vitro force assessment. Results Collagens I, III, and VI localized to the endomysium, perimysium, and epimysium. Collagen IV, fibronectin, and laminin localized to the basal lamina surrounding all myofibers. All collagens localized similarly in the orbital and global layers throughout the muscle length. Elastin had the most irregular pattern and ran longitudinally and circumferentially throughout the length of all EOMs. Scanning electron microscopy showed these elements to be extensively interconnected, from endomysium through the perimysium to the epimysium surrounding the whole muscle. In vitro physiology demonstrated force generation in the lateral dimension, presumably through myofascial transmission, which was always proportional to the force generated in the longitudinally oriented muscles. Conclusions A striking connective tissue matrix interconnects all the myofibers and extends, via perimysial connections, to the epimysium. These interconnections are significant and allow measurable force transmission laterally as well as longitudinally, suggesting that they may contribute to the nonlinear force summation seen in motor unit recording studies. This provides strong evidence that separate compartmental movements are unlikely as no region is independent of the rest of the muscle. PMID:29346490

  3. Ultra structure of the denervated vocal muscle mechanically in hogs (sus scrofa domestica

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    Leão, Henrique Zaquia

    2010-03-01

    Full Text Available Introduction: The literature is not clear in the ultra-structural manifestations of the vocal wrinkles after neural wound. Objective: To verify the alterations that occur in a vocal fold mechanically denervated. Method: In this prospective study, it were utilized 15 hogs of commercial race (Sus scrofa domesticates, with age of 4 to 12 weeks. The animals were distributed in three groups, chosen at random. Everybody was submitted to the denervation of the right vocal fold, with surgical removal of a segment with three centimeters of the recurring right laryngeal nerve. After 45, 90 and 180 days of the operations, it was proceeded the biopsy of the vocal muscles, it was prosecuted the samples for transmission electron microscopy and, for the ultra-structural study, utilized the transmission electron microscopy Philips, model EM208S. Results: The biopsied groups with 45 and 90 days after operation of mechanical denervation, presented disorganization miofibrilar, only vestigial lines Z in many samples, as well like altered mithochondrions presenting limited sizes, and matrix mithocondrial rarefied with rare mithocondrial cristae present. The biopsied group with 180 days after operation of denervation, presented regular sarcomeres, mithocondrions with sizes and regular number with correct positioning between the sarcomerical units. Conclusion: The finds in the ultra-structure of the vocal muscles suggest to re enervation of the muscle being that the muscular mithochondrions were the most sensible structures to the denervated condition, successions by the cytoarchiteture of the miofibrilas; the finds in the ultra-structure of the vocal muscles suggests to reinervation of the muscle in the period of approximately six months.

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

    International Nuclear Information System (INIS)

    Gao, Yingxin; Zhang, Chi

    2015-01-01

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

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

    Science.gov (United States)

    Gao, Yingxin; Zhang, Chi

    2015-03-01

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

  6. Aerobic metabolism on muscle contraction in porcine gastric smooth muscle.

    Science.gov (United States)

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

    2018-05-18

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

  7. Regulation of skeletal muscle oxidative capacity and muscle mass by SIRT3.

    Directory of Open Access Journals (Sweden)

    Ligen Lin

    Full Text Available We have previously reported that the expression of mitochondrial deacetylase SIRT3 is high in the slow oxidative muscle and that the expression of muscle SIRT3 level is increased by dietary restriction or exercise training. To explore the function of SIRT3 in skeletal muscle, we report here the establishment of a transgenic mouse model with muscle-specific expression of the murine SIRT3 short isoform (SIRT3M3. Calorimetry study revealed that the transgenic mice had increased energy expenditure and lower respiratory exchange rate (RER, indicating a shift towards lipid oxidation for fuel usage, compared to control mice. The transgenic mice exhibited better exercise performance on treadmills, running 45% further than control animals. Moreover, the transgenic mice displayed higher proportion of slow oxidative muscle fibers, with increased muscle AMPK activation and PPARδ expression, both of which are known regulators promoting type I muscle fiber specification. Surprisingly, transgenic expression of SIRT3M3 reduced muscle mass up to 30%, likely through an up-regulation of FOXO1 transcription factor and its downstream atrophy gene MuRF-1. In summary, these results suggest that SIRT3 regulates the formation of oxidative muscle fiber, improves muscle metabolic function, and reduces muscle mass, changes that mimic the effects of caloric restriction.

  8. Biologically inspired technologies using artificial muscles

    Science.gov (United States)

    Bar-Cohen, Yoseph

    2005-01-01

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

  9. Mitochondrial respiration is decreased in skeletal muscle of patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Hey-Mogensen, Martin; Sahlin, Kent; Fernström, Maria

    2007-01-01

    , and the proportion of type 2X fibers correlated with markers of insulin resistance (P type 2X fibers in muscle of type 2 diabetic patients. These alterations may contribute to the development......We tested the hypothesis of a lower respiratory capacity per mitochondrion in skeletal muscle of type 2 diabetic patients compared with obese subjects. Muscle biopsies obtained from 10 obese type 2 diabetic and 8 obese nondiabetic male subjects were used for assessment of 3-hydroxy....... Maximal ADP-stimulated respiration (state 3) with pyruvate plus malate and respiration through the electron transport chain (ETC) were reduced in type 2 diabetic patients, and the proportion of type 2X fibers were higher in type 2 diabetic patients compared with obese subjects (all P

  10. Human skeletal muscle fibroblasts stimulate in vitro myogenesis and in vivo muscle regeneration

    DEFF Research Database (Denmark)

    Mackey, Abigail L; Magnan, Mélanie; Chazaud, Bénédicte

    2017-01-01

    immediately surrounding regenerating muscle fibres. These novel findings indicate an important role for fibroblasts in supporting the regeneration of muscle fibres, potentially through direct stimulation of satellite cell differentiation and fusion, and contribute to understanding of cell-cell cross......-talk during physiological and pathological muscle remodelling. ABSTRACT: Accumulation of skeletal muscle extracellular matrix is an unfavourable characteristic of many muscle diseases, muscle injury and sarcopenia. In addition to the indispensable role satellite cells play in muscle regeneration......, there is emerging evidence in rodents for a regulatory influence on fibroblast activity. However, the influence of fibroblasts on satellite cells and muscle regeneration in humans is unknown. The purpose of this study was to investigate this in vitro and during in vivo regeneration in humans. Following a muscle...

  11. Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation.

    Science.gov (United States)

    Gay, André; Aimonetti, Jean-Marc; Roll, Jean-Pierre; Ribot-Ciscar, Edith

    2015-07-30

    In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (-51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (-38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Serum antibody responses in pigs trickle-infected with Ascaris and Trichuris

    DEFF Research Database (Denmark)

    Kringel, Helene; Thamsborg, Stig Milan; Petersen, Heidi Huus

    2015-01-01

    A humoral immune response following helminth infection in pigs is well documented. However, it has been difficult to confirm the existence of antibody mediated resistance against the large roundworm, Ascaris suum, and whipworm, Trichuris suis, in experimental settings by correlating worm burdens...... or egg excretion with specific antibody levels. We set out to investigate the association between worm load and T. suis and A. suum specific serum antibody levels (IgG1, IgG2 and IgA) against excretory-secretory products of adults and third stage larvae, respectively, measured at 0, 7 and 14 weeks p.......i. in a trickle-infected F1-resource-population of crossbred pigs (n=195). Furthermore, we wanted to determine the heritability of these antibody isotypes during the course of infection. Most pigs remained infected with A. suum throughout the experiment while they expelled T. suis between 7 and 14 weeks post...

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

    Science.gov (United States)

    Roy, Sudipto; VijayRaghavan, K.

    1998-01-01

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

  14. Effect of transcutaneous electrical muscle stimulation on postoperative muscle mass and protein synthesis

    DEFF Research Database (Denmark)

    Vinge, O; Edvardsen, L; Jensen, F

    1996-01-01

    In an experimental study, 13 patients undergoing major elective abdominal surgery were given postoperative transcutaneous electrical muscle stimulation (TEMS) to the quadriceps femoris muscle on one leg; the opposite leg served as control. Changes in cross-sectional area (CSA) and muscle protein ...... protein synthesis and muscle mass after abdominal surgery and should be evaluated in other catabolic states with muscle wasting.......In an experimental study, 13 patients undergoing major elective abdominal surgery were given postoperative transcutaneous electrical muscle stimulation (TEMS) to the quadriceps femoris muscle on one leg; the opposite leg served as control. Changes in cross-sectional area (CSA) and muscle protein...... synthesis were assessed by computed tomography and ribosome analysis of percutaneous muscle biopsies before surgery and on the sixth postoperative day. The percentage of polyribosomes in the ribosome suspension decreased significantly (P

  15. Muscular hypertrophy and atrophy in normal rats provoked by the administration of normal and denervated muscle extracts.

    Science.gov (United States)

    Agüera, Eduardo; Castilla, Salvador; Luque, Evelio; Jimena, Ignacio; Leiva-Cepas, Fernando; Ruz-Caracuel, Ignacio; Peña, José

    2016-12-01

    This study was conducted to determine the effects of extracts obtained from both normal and denervated muscles on different muscle types. Wistar rats were used and were divided into a control group and four experimental groups. Each experimental group was treated intraperitoneally during 10 consecutive days with a different extract. These extracts were obtained from normal soleus muscle, denervated soleus, normal extensor digitorum longus, and denervated extensor digitorum longus. Following treatment, the soleus and extensor digitorum longus muscles were obtained for study under optic and transmission electron microscope; morphometric parameters and myogenic responses were also analyzed. The results demonstrated that the treatment with normal soleus muscle and denervated soleus muscle extracts provoked hypertrophy and increased myogenic activity. In contrast, treatment with extracts from the normal and denervated EDL had a different effect depending on the muscle analyzed. In the soleus muscle it provoked hypertrophy of type I fibers and increased myogenic activity, while in the extensor digitorum longus atrophy of the type II fibers was observed without changes in myogenic activity. This suggests that the muscular responses of atrophy and hypertrophy may depend on different factors related to the muscle type which could be related to innervation.

  16. The arrangement of muscle fibers and tendons in two muscles used for growth studies.

    Science.gov (United States)

    Stickland, N C

    1983-01-01

    The arrangement of muscle fibres and tendons was examined in the soleus muscle of rats from 6 to 175 days post partum. The muscle was seen to change from a simple structure, with mean fibre length of approximately 90% of complete muscle length, to a unipennate structure, with mean fibre length of only about 60% of muscle length. The dog pectineus muscle was also investigated and found to have a bipennate structure throughout postnatal growth. The arrangement of muscle fibres in both these muscles is such that it might be difficult (particularly in the older animals) to cut a transverse section through all the fibres contained in the muscle; some fibres might not enter the plane of section. Results on muscle fibre number in these muscles at different ages may therefore be misleading.

  17. Muscle spindle autogenetic inhibition in the extraocular muscles of lamb.

    Science.gov (United States)

    Pettorossi, V E; Filippi, G M

    1981-09-01

    The role of extraocular muscle (EOM) proprioceptors on eye motility has been investigated in lambs on "encéphale isolé", by evaluating the tension of EOMs at various lengths and velocities of stretch before and after proprioceptive blocks. The EOM tension, in the absence of proprioceptive input, was higher than in normal conditions. Such an effect occurred at lengthening values greater than 3 mm of stretch from resting muscle length, corresponding to 18 degrees of eye deviation and was dependent on the velocity of the stretch, being more effective at high velocity. The muscle receptors responsible for this effect was determined by comparing the sensitivity to vibratory stimulation of spindles and tendon organs to the amount of inhibition provoked by the same stimulation on an EOM electromyographic activity. The tension inhibition appeared to be correlated to muscle spindle activation. Thus, the presence of muscle spindles can determine a reduction of the tension within the stretched muscles. This result suggests that the EOM length and velocity signals operate moment to moment reduction on the stiffness of the muscle which antagonizes eye displacement, thus facilitating the ocular movements.

  18. Reconstruction of the muscle system in Antygomonas sp. (Kinorhyncha, Cyclorhagida) by means of phalloidin labeling and cLSM.

    Science.gov (United States)

    Müller, Monika C M; Schmidt-Rhaesa, Andreas

    2003-05-01

    In the present investigation the entire muscle system of the cyclorhagid kinorhynch Antygomonas sp. was three-dimensionally reconstructed from whole mounts by means of FITC-phalloidin labeling and confocal scanning microscopy. With this technique, which proved to be especially useful for microscopically small species, we wanted to reinvestigate and supplement the findings obtained by histological and electron microscopical methods. The organization of the major muscle systems can be summarized as follows: 1) All muscle fibers, apart from the intestinal ones, the spine, and the mouth cone muscles, show a cross-striated pattern; 2) Dorsal longitudinal muscle fibers as well as segmentally arranged dorsoventral fibers occur from segment III to XIII; 3) Diagonal muscle fibers are located laterally in segments III to X; 4) Two rings of circular fibers are present in segment II, forming the closing apparatus in Cyclorhagida. Further circular muscles are present in segment I, forming the mouth cone and the eversible introvert, and in the pharyngeal bulb. Copyright 2003 Wiley-Liss, Inc.

  19. Acupuncture plus Low-Frequency Electrical Stimulation (Acu-LFES Attenuates Diabetic Myopathy by Enhancing Muscle Regeneration.

    Directory of Open Access Journals (Sweden)

    Zhen Su

    Full Text Available Mortality and morbidity are increased in patients with muscle atrophy resulting from catabolic diseases such as diabetes. At present there is no pharmacological treatment that successfully reverses muscle wasting from catabolic conditions. We hypothesized that acupuncture plus low frequency electric stimulation (Acu-LFES would mimic the impact of exercise and prevent diabetes-induced muscle loss. Streptozotocin (STZ was used to induce diabetes in mice. The mice were then treated with Acu-LFES for 15 minutes daily for 14 days. Acupuncture points were selected according to the WHO Standard Acupuncture Nomenclature guide. The needles were connected to an SDZ-II electronic acupuncture device delivering pulses at 20Hz and 1mA. Acu-LFES prevented soleus and EDL muscle weight loss and increased hind-limb muscle grip function in diabetic mice. Muscle regeneration capacity was significantly increased by Acu-LFES. The expression of Pax7, MyoD, myogenin and embryo myosin heavy chain (eMyHC was significantly decreased in diabetic muscle vs. control muscle. The suppressed levels in diabetic muscle were reversed by Acu-LFES. The IGF-1 signaling pathway was also upregulated by Acu-LFES. Phosphorylation of Akt, mTOR and p70S6K were downregulated by diabetes leading to a decline in muscle mass, however, Acu-LFES countered the diabetes-induced decline. In addition, microRNA-1 and -206 were increased by Acu-LFES after 24 days of treatment. We conclude that Acu-LFES is effective in counteracting diabetes-induced skeletal muscle atrophy by increasing IGF-1 and its stimulation of muscle regeneration.

  20. Eosinophilia of dystrophin-deficient muscle is promoted by perforin-mediated cytotoxicity by T cell effectors

    Science.gov (United States)

    Cai, B.; Spencer, M. J.; Nakamura, G.; Tseng-Ong, L.; Tidball, J. G.

    2000-01-01

    Previous investigations have shown that cytotoxic T lymphocytes (CTLs) contribute to muscle pathology in the dystrophin-null mutant mouse (mdx) model of Duchenne muscular dystrophy through perforin-dependent and perforin-independent mechanisms. We have assessed whether the CTL-mediated pathology includes the promotion of eosinophilia in dystrophic muscle, and thereby provides a secondary mechanism through which CTLs contribute to muscular dystrophy. Quantitative immunohistochemistry confirmed that eosinophilia is a component of the mdx dystrophy. In addition, electron microscopic observations show that eosinophils traverse the basement membrane of mdx muscle fibers and display sites of close apposition of eosinophil and muscle membranes. The close membrane apposition is characterized by impingement of eosinophilic rods of major basic protein into the muscle cell membrane. Transfer of mdx splenocytes and mdx muscle extracts to irradiated C57 mice by intraperitoneal injection resulted in muscle eosinophilia in the recipient mice. Double-mutant mice lacking dystrophin and perforin showed less eosinophilia than was displayed by mdx mice that expressed perforin. Finally, administration of prednisolone, which has been shown previously to reduce the concentration of CTLs in dystrophic muscle, produced a significant reduction in eosinophilia. These findings indicate that eosinophilia is a component of the mdx pathology that is promoted by perforin-dependent cytotoxicity of effector T cells. However, some eosinophilia of mdx muscle is independent of perforin-mediated processes.

  1. Skeletal muscle atrophy in bioengineered skeletal muscle: a new model system.

    Science.gov (United States)

    Lee, Peter H U; Vandenburgh, Herman H

    2013-10-01

    Skeletal muscle atrophy has been well characterized in various animal models, and while certain pathways that lead to disuse atrophy and its associated functional deficits have been well studied, available drugs to counteract these deficiencies are limited. An ex vivo tissue-engineered skeletal muscle offers a unique opportunity to study skeletal muscle physiology in a controlled in vitro setting. Primary mouse myoblasts isolated from adult muscle were tissue engineered into bioartificial muscles (BAMs) containing hundreds of aligned postmitotic muscle fibers expressing sarcomeric proteins. When electrically stimulated, BAMs generated measureable active forces within 2-3 days of formation. The maximum isometric tetanic force (Po) increased for ∼3 weeks to 2587±502 μN/BAM and was maintained at this level for greater than 80 days. When BAMs were reduced in length by 25% to 50%, muscle atrophy occurred in as little as 6 days. Length reduction resulted in significant decreases in Po (50.4%), mean myofiber cross-sectional area (21.7%), total protein synthesis rate (22.0%), and noncollagenous protein content (6.9%). No significant changes occurred in either the total metabolic activity or protein degradation rates. This study is the first in vitro demonstration that length reduction alone can induce skeletal muscle atrophy, and establishes a novel in vitro model for the study of skeletal muscle atrophy.

  2. MUSCLE DISORDERS IN ADOLESCENT IDIOPATHIC SCOLIOSIS: LITERATURE REVIEW

    OpenAIRE

    Débora Pinheiro Lédio Alves; Barbara de Araújo

    2016-01-01

    ABSTRACT Scoliosis is characterized by three-dimensional changes of the spine and is estimated to be present in 4% of the population worldwide. The most common form is the adolescent idiopathic. The purpose of this study is to identify the major muscle abnormalities found in patients with adolescent idiopathic scoliosis through a literature review. We conducted an electronic search of the national databases PubMed, Lilacs, PEDro, and EMBASE using the keywords "scoliosis", "biomechanics", "exe...

  3. Striation Patterns of Ox Muscle in Rigor Mortis

    Science.gov (United States)

    Locker, Ronald H.

    1959-01-01

    Ox muscle in rigor mortis offers a selection of myofibrils fixed at varying degrees of contraction from sarcomere lengths of 3.7 to 0.7 µ. A study of this material by phase contrast and electron microscopy has revealed four distinct successive patterns of contraction, including besides the familiar relaxed and contracture patterns, two intermediate types (2.4 to 1.9 µ, 1.8 to 1.5 µ) not previously well described. PMID:14417790

  4. Bone Marrow Stromal Cells Generate Muscle Cells and Repair Muscle Degeneration

    Science.gov (United States)

    Dezawa, Mari; Ishikawa, Hiroto; Itokazu, Yutaka; Yoshihara, Tomoyuki; Hoshino, Mikio; Takeda, Shin-ichi; Ide, Chizuka; Nabeshima, Yo-ichi

    2005-07-01

    Bone marrow stromal cells (MSCs) have great potential as therapeutic agents. We report a method for inducing skeletal muscle lineage cells from human and rat general adherent MSCs with an efficiency of 89%. Induced cells differentiated into muscle fibers upon transplantation into degenerated muscles of rats and mdx-nude mice. The induced population contained Pax7-positive cells that contributed to subsequent regeneration of muscle upon repetitive damage without additional transplantation of cells. These MSCs represent a more ready supply of myogenic cells than do the rare myogenic stem cells normally found in muscle and bone marrow.

  5. Muscle fatigue in fibromyalgia is in the brain, not in the muscles

    DEFF Research Database (Denmark)

    Bandak, Elisabeth; Amris, Kirstine; Bliddal, Henning

    2013-01-01

    To investigate relationships between perceived and objectively measured muscle fatigue during exhausting muscle contractions in women with fibromyalgia (FM) compared with healthy controls (HC).......To investigate relationships between perceived and objectively measured muscle fatigue during exhausting muscle contractions in women with fibromyalgia (FM) compared with healthy controls (HC)....

  6. Response of macrophages in rat skeletal muscle after eccentric exercise.

    Science.gov (United States)

    Zuo, Qun; Wang, Shu-Chen; Yu, Xin-Kai; Chao, Wei-Wei

    2018-04-01

    Macrophages are known to be important for healing numerous injured tissues depending on their functional phenotypes in response to different stimuli. The objective of this study was to reveal macrophage phenotypic changes involved in exercise-induced skeletal muscle injury and regeneration. Adult male Sprague-Dawley rats experienced one session of downhill running (16° decline, 16 m/min) for 90 min. After exercise the blood and soleus muscles were collected at 0 h, 6 h, 12 h, 1 d, 2 d, 3 d, 1 w and 2 w after exercise, separately. It was showed that CD68 + M1 macrophages mainly infiltrated into muscle necrotic sites at 1-3 d, while CD163 + M2 macrophages were present in muscles from 0 h to 2 weeks after exercise. Using transmission electron microscopy, we observed activated satellite cells 1 d after exercise. Th1-associated transcripts of iNOS and Ccl2 were inhibited post exercise, while COX-2 mRNA was dramatically increased 12 h after running (p < 0.01). M2 phenotype marker Arg-1 increased 12 h and 3 d (p < 0.05, p < 0.01) after exercise, and Clec10a and Mrc2 were up-regulated in muscles 12 h following exercise (p < 0.05, p < 0.05). The data demonstrate the dynamic patterns of macrophage phenotype in skeletal muscle upon eccentric exercise stimuli, and M1 and M2 phenotypes perform different functions during exercise-induced skeletal muscle injury and recovery. Copyright © 2018 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Katherine Muterspaugh Steele

    2013-08-01

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

  8. Comparison of Mitochondrial Reactive Oxygen Species Production of Ectothermic and Endothermic Fish Muscle

    Directory of Open Access Journals (Sweden)

    Lilian Wiens

    2017-09-01

    Full Text Available Recently we demonstrated that the capacity of isolated muscle mitochondria to produce reactive oxygen species, measured as H2O2 efflux, is temperature-sensitive in isolated muscle mitochondria of ectothermic fish and the rat, a representative endothermic mammal. However, at physiological temperatures (15° and 37°C for the fish and rat, respectively, the fraction of total mitochondrial electron flux that generated H2O2, the fractional electron leak (FEL, was far lower in the rat than in fish. Those results suggested that the elevated body temperatures associated with endothermy may lead to a compensatory decrease in mitochondrial ROS production relative to respiratory capacity. To test this hypothesis we compare slow twitch (red muscle mitochondria from the endothermic Pacific bluefin tuna (Thunnus orientalis with mitochondria from three ectothermic fishes [rainbow trout (Oncorhynchus mykiss, common carp (Cyprinus carpio, and the lake sturgeon (Acipenser fulvescens] and the rat. At a common assay temperature (25°C rates of mitochondrial respiration and H2O2 efflux were similar in tuna and the other fishes. The thermal sensitivity of fish mitochondria was similar irrespective of ectothermy or endothermy. Comparing tuna to the rat at a common temperature, respiration rates were similar, or lower depending on mitochondrial substrates. FEL was not different across fish species at a common assay temperature (25°C but was markedly higher in fishes than in rat. Overall, endothermy and warming of Pacific Bluefin tuna red muscle may increase the potential for ROS production by muscle mitochondria but the evolution of endothermy in this species is not necessarily associated with a compensatory reduction of ROS production relative to the respiratory capacity of mitochondria.

  9. 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.

  10. Onset of rigor mortis is earlier in red muscle than in white muscle.

    Science.gov (United States)

    Kobayashi, M; Takatori, T; Nakajima, M; Sakurada, K; Hatanaka, K; Ikegaya, H; Matsuda, Y; Iwase, H

    2000-01-01

    Rigor mortis is thought to be related to falling ATP levels in muscles postmortem. We measured rigor mortis as tension determined isometrically in three rat leg muscles in liquid paraffin kept at 37 degrees C or 25 degrees C--two red muscles, red gastrocnemius (RG) and soleus (SO) and one white muscle, white gastrocnemius (WG). Onset, half and full rigor mortis occurred earlier in RG and SO than in WG both at 37 degrees C and at 25 degrees C even though RG and WG were portions of the same muscle. This suggests that rigor mortis directly reflects the postmortem intramuscular ATP level, which decreases more rapidly in red muscle than in white muscle after death. Rigor mortis was more retarded at 25 degrees C than at 37 degrees C in each type of muscle.

  11. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, William G., E-mail: bp1@bu.edu [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States); Hindson, David F. [Department of Radiology, Boston Medical Center, Boston, Massachusetts (United States); Langmore, Susan E. [Department of Otolaryngology, Boston Medical Center, Boston, Massachusetts (United States); Speech and Hearing Sciences, Boston University, Boston, Massachusetts (United States); Zumwalt, Ann C. [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States)

    2013-03-01

    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

  13. Modulation effects of cordycepin on the skeletal muscle contraction of toad gastrocnemius muscle.

    Science.gov (United States)

    Yao, Li-Hua; Meng, Wei; Song, Rong-Feng; Xiong, Qiu-Ping; Sun, Wei; Luo, Zhi-Qiang; Yan, Wen-Wen; Li, Yu-Ping; Li, Xin-Ping; Li, Hai-Hang; Xiao, Peng

    2014-03-05

    Isolated toad gastrocnemius muscle is a typical skeletal muscle tissue that is frequently used to study the motor system because it is an important component of the motor system. This study investigates the effects of cordycepin on the skeletal muscle contractile function of isolated toad gastrocnemius muscles by electrical field stimulation. Results showed that cordycepin (20 mg/l to 100 mg/l) significantly decreased the contractile responses in a concentration-dependent manner. Cordycepin (50 mg/l) also produced a rightward shift of the contractile amplitude-stimulation intensity relationship, as indicated by the increases in the threshold stimulation intensity and the saturation stimulation intensity. However, the most notable result was that the maximum amplitude of the muscle contractile force was significantly increased under cordycepin application (122±3.4% of control). This result suggests that the skeletal muscle contractile function and muscle physical fitness to the external stimulation were improved by the decreased response sensitivity in the presence of cordycepin. Moreover, cordycepin also prevented the repetitive stimulation-induced decrease in muscle contractile force and increased the recovery amplitude and recovery ratio of muscle contraction. However, these anti-fatigue effects of cordycepin on muscle contraction during long-lasting muscle activity were absent in Ca2+-free medium or in the presence of all Ca2+ channels blocker (0.4 mM CdCl2). These results suggest that cordycepin can positively affect muscle performance and provide ergogenic and prophylactic benefits in decreasing skeletal muscle fatigue. The mechanisms involving excitation-coupled Ca2+ influxes are strongly recommended.

  14. Detection of muscle gap by L-BIA in muscle injuries: clinical prognosis.

    Science.gov (United States)

    Nescolarde, L; Yanguas, J; Terricabras, J; Lukaski, H; Alomar, X; Rosell-Ferrer, J; Rodas, G

    2017-06-21

    Sport-related muscle injury classifications are based basically on imaging criteria such as ultrasound (US) and magnetic resonance imaging (MRI) without consensus because of a lack of clinical prognostics for return-to-play (RTP), which is conditioned upon the severity of the injury, and this in turn with the muscle gap (muscular fibers retraction). Recently, Futbol Club Barcelona's medical department proposed a new muscle injury classification in which muscle gap plays an important role, with the drawback that it is not always possible to identify by MRI. Localized bioimpedance measurement (L-BIA) has emerged as a non-invasive technique for supporting US and MRI to quantify the disrupted soft tissue structure in injured muscles. To correlate the severity of the injury according to the gap with the RTP, through the percent of change in resistance (R), reactance (Xc) and phase-angle (PA) by L-BIA measurements in 22 muscle injuries. After grouping the data according to the muscle gap (by MRI exam), there were significant differences in R between grade 1 and grade 2f (myotendinous or myofascial muscle injury with feather-like appearance), as well as between grade 2f and grade 2g (myotendinous or myofascial muscle injury with feather and gap). The Xc and PA values decrease significantly between each grade (i.e. 1 versus 2f, 1 versus 2g and 2f versus 2g). In addition, the severity of the muscle gap adversely affected the RTP with significant differences observed between 1 and 2g as well as between 2f and 2g. These results show that L-BIA could aid MRI and US in identifying the severity of an injured muscle according to muscle gap and therefore to accurately predict the RTP.

  15. Changes in muscle fiber contractility and extracellular matrix production during skeletal muscle hypertrophy.

    Science.gov (United States)

    Mendias, Christopher L; Schwartz, Andrew J; Grekin, Jeremy A; Gumucio, Jonathan P; Sugg, Kristoffer B

    2017-03-01

    Skeletal muscle can adapt to increased mechanical loads by undergoing hypertrophy. Transient reductions in whole muscle force production have been reported during the onset of hypertrophy, but contractile changes in individual muscle fibers have not been previously studied. Additionally, the extracellular matrix (ECM) stores and transmits forces from muscle fibers to tendons and bones, and determining how the ECM changes during hypertrophy is important in understanding the adaptation of muscle tissue to mechanical loading. Using the synergist ablation model, we sought to measure changes in muscle fiber contractility, collagen content, and cross-linking, and in the expression of several genes and activation of signaling proteins that regulate critical components of myogenesis and ECM synthesis and remodeling during muscle hypertrophy. Tissues were harvested 3, 7, and 28 days after induction of hypertrophy, and nonoverloaded rats served as controls. Muscle fiber specific force (sF o ), which is the maximum isometric force normalized to cross-sectional area, was reduced 3 and 7 days after the onset of mechanical overload, but returned to control levels by 28 days. Collagen abundance displayed a similar pattern of change. Nearly a quarter of the transcriptome changed over the course of overload, as well as the activation of signaling pathways related to hypertrophy and atrophy. Overall, this study provides insight into fundamental mechanisms of muscle and ECM growth, and indicates that although muscle fibers appear to have completed remodeling and regeneration 1 mo after synergist ablation, the ECM continues to be actively remodeling at this time point. NEW & NOTEWORTHY This study utilized a rat synergist ablation model to integrate changes in single muscle fiber contractility, extracellular matrix composition, activation of important signaling pathways in muscle adaption, and corresponding changes in the muscle transcriptome to provide novel insight into the basic

  16. Muscle as a secretory organ

    DEFF Research Database (Denmark)

    Pedersen, Bente K

    2013-01-01

    Skeletal muscle is the largest organ in the body. Skeletal muscles are primarily characterized by their mechanical activity required for posture, movement, and breathing, which depends on muscle fiber contractions. However, skeletal muscle is not just a component in our locomotor system. Recent e...... proteins produced by skeletal muscle are dependent upon contraction. Therefore, it is likely that myokines may contribute in the mediation of the health benefits of exercise.......Skeletal muscle is the largest organ in the body. Skeletal muscles are primarily characterized by their mechanical activity required for posture, movement, and breathing, which depends on muscle fiber contractions. However, skeletal muscle is not just a component in our locomotor system. Recent...... evidence has identified skeletal muscle as a secretory organ. We have suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers and exert either autocrine, paracrine, or endocrine effects should be classified as "myokines." The muscle secretome consists...

  17. The arrangement of muscle fibers and tendons in two muscles used for growth studies.

    OpenAIRE

    Stickland, N C

    1983-01-01

    The arrangement of muscle fibres and tendons was examined in the soleus muscle of rats from 6 to 175 days post partum. The muscle was seen to change from a simple structure, with mean fibre length of approximately 90% of complete muscle length, to a unipennate structure, with mean fibre length of only about 60% of muscle length. The dog pectineus muscle was also investigated and found to have a bipennate structure throughout postnatal growth. The arrangement of muscle fibres in both these mus...

  18. Characterization of ascaris from ecuador and zanzibar.

    Science.gov (United States)

    Sparks, A M; Betson, M; Oviedo, G; Sandoval, C; Cooper, P J; Stothard, J R

    2015-07-01

    To shed light on the epidemiology of ascariasis in Ecuador and Zanzibar, 177 adult worms retrieved by chemo-expulsion from either people or pigs were collected, measured and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the ribosomal internal transcribed spacer (ITS) region. Upon double digestion with RsaI and HaeIII, PCR-RFLP analysis revealed the presence of A. lumbricoides in people and A. suum in pigs in Ecuador. In contrast, while there are no pigs on Zanzibar, of the 56 worms obtained from people, one was genotyped as A. suum. No additional genetic variation was detected upon further PCR-RFLP analysis with several other restriction enzymes. Upon measurement, worm mass and length differed by location and by species, A. suum being lighter and longer. While there is no evidence to suggest zoonotic transmission in Ecuador, an enduring historical signature of previous zoonotic transmission remains on Zanzibar.

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    Dzahir M.A.M

    2017-01-01

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

  1. Human skeletal muscle fibroblasts stimulate in vitro myogenesis and in vivo muscle regeneration

    DEFF Research Database (Denmark)

    Mackey, Abigail L.; Magnan, Mélanie; Chazaud, Bénédicte

    2017-01-01

    Accumulation of skeletal muscle extracellular matrix is an unfavourable characteristic of many muscle diseases, muscle injury and sarcopenia. In addition to the indispensable role satellite cells play in muscle regeneration, there is emerging evidence in rodents for a regulatory influence...

  2. Vanilloid receptor expressed in the sarcoplasmic reticulum of rat skeletal muscle

    International Nuclear Information System (INIS)

    Xin Hong; Tanaka, Hideyuki; Yamaguchi, Maki; Takemori, Shigeru; Nakamura, Akio; Kohama, Kazuhiro

    2005-01-01

    Vanilloid receptor subtype 1 (VR1) was cloned as a capsaicin receptor from neuronal cells of dorsal root ganglia. VR1 was subsequently found in a few non-neuronal tissues, including skeletal muscle [Onozawa et al., Tissue distribution of capsaicin receptor in the various organs of rats, Proc. Jpn. Acad. Ser. B 76 (2000) 68-72]. We confirmed the expression of VR1 in muscle cells using the RT-PCR method and Western blot analysis. Immunostaining studies with a confocal microscope and an electron microscope indicated that VR1 was present in the sarcoplasmic reticulum (SR), a store of Ca 2+ . The SR releases Ca 2+ to cause a contraction when a muscle is excited. However, SR still releases a small amount of Ca 2+ under relaxed conditions. We found that this leakage was enhanced by capsaicin and was antagonized by capsazepine, a capsaicin blocker, indicating that leakage of Ca 2+ occurs through a channel composed of VR1

  3. Endurance training facilitates myoglobin desaturation during muscle contraction in rat skeletal muscle.

    Science.gov (United States)

    Takakura, Hisashi; Furuichi, Yasuro; Yamada, Tatsuya; Jue, Thomas; Ojino, Minoru; Hashimoto, Takeshi; Iwase, Satoshi; Hojo, Tatsuya; Izawa, Tetsuya; Masuda, Kazumi

    2015-03-24

    At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mVO2). However, whether the change in PmbO2 during muscle contraction modulates mVO2 and whether the O2 release rate from Mb increases in endurance-trained muscles remain unclear. The purpose of this study was, therefore, to determine the effect of endurance training on O2 saturation of Mb (SmbO2) and PmbO2 kinetics during muscle contraction. Male Wistar rats were subjected to a 4-week swimming training (Tr group; 6 days per week, 30 min × 4 sets per day) with a weight load of 2% body mass. After the training period, deoxygenated Mb kinetics during muscle contraction were measured using near-infrared spectroscopy under hemoglobin-free medium perfusion. In the Tr group, the VmO2peak significantly increased by 32%. Although the PmbO2 during muscle contraction did not affect the increased mVO2 in endurance-trained muscle, the O2 release rate from Mb increased because of the increased Mb concentration and faster decremental rate in SmbO2 at the maximal twitch tension. These results suggest that the Mb dynamics during muscle contraction are contributing factors to faster VO2 kinetics in endurance-trained muscle.

  4. 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

  5. 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.

  6. Reduced muscle fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears.

    Science.gov (United States)

    Mendias, Christopher L; Roche, Stuart M; Harning, Julie A; Davis, Max E; Lynch, Evan B; Sibilsky Enselman, Elizabeth R; Jacobson, Jon A; Claflin, Dennis R; Calve, Sarah; Bedi, Asheesh

    2015-01-01

    A persistent atrophy of muscle fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that muscles from patients with chronic rotator cuff tears have reduced muscle fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. The contractility of muscle fibers from biopsy specimens of supraspinatus muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis muscle fibers. Correlations between muscle fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. Torn supraspinatus muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus muscle fibers. Patients with chronic supraspinatus tears have significant reductions in muscle fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional muscle dysfunction of the residual muscle fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore muscle function after the repair of chronically torn rotator cuff muscles. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  7. Morphology of the lateral pterygoid muscle associated to the mandibular condyle in the human prenatal stage.

    Science.gov (United States)

    Carranza, Miriam L; Carda, Carmen; Simbrón, Alicia; Quevedo, María C Sánchez; Celaya, Gabriela; de Ferraris, Maria Elsa Gómez

    2006-01-01

    The lateral pterygoid muscle (LPM) inserts at the condyle and the articular disc and plays a central role in mandibular movement via the Temporomandibular Articular Complex. The aim of this study was to examine the association between the morphology of LPM muscular fascicles and the degree of mineralization of the mandibular condyle in the prenatal stage employing structural, ultrastructural and microanalytical evaluation. Sixteen human fetuses at 11-37 weeks of gestation, with no apparent pathology and resulting from spontaneous abortions, were included in the study. Samples from lateral pterygoid muscle and the mandibular condyle were processed for light microscopy and electron microscopy and microanalysis. Desmin immunolabeling (dilution 1: 25 Dako) and alpha sarcomeric actin immunolabeling (dilution 1:50 Dako) employing the avidin-biotin system were used in paraffin embedded samples. Contralateral samples were examine by transmission electron microscopy. Four condyles (at 17-21 weeks of gestation) were used to measure the relative content of calcium and phosphorous employing the X-ray diffraction microanalytical technique. At 11-16 weeks of gestation, the LPM was composed of secondary myotubes associated to satellite cells and nerve fibers. At 18 weeks, the muscle exhibited multiple compact fascicles and the condyle showed a thin, external, subperiostal mineralized layer with few central bone spicules. At 20 weeks, at the site of insertion of the LPM, the bone trabeculae of the condyle contained an electrondense matrix with abundant mineralization nuclei. At 17-21 weeks of gestation no significant variations in the contents of phosphorous and calcium were observed. At 24 weeks, transmission electron calcium and microscopy studies revealed a marked increase in the functional units of the muscle fascicles. Also, at this age muscle fibers exhibited differences in the expression of desmin and alpha sarcomeric actin. At 37 weeks the muscle became multipennate in

  8. Muscle fiber population and biochemical properties of whole body muscles in Thoroughbred horses.

    Science.gov (United States)

    Kawai, Minako; Minami, Yoshio; Sayama, Yukiko; Kuwano, Atsutoshi; Hiraga, Atsushi; Miyata, Hirofumi

    2009-10-01

    We examine the muscle fiber population and metabolic properties of skeletal muscles from the whole body in Thoroughbred horses. Postmortem samples were taken from 46 sites in six Thoroughbred horses aged between 3 and 6 years. Fiber type population was determined on muscle fibers stained with monoclonal antibody to each myosin heavy chain isoform and metabolic enzyme activities were determined spectrophotometrically. Histochemical analysis demonstrated that most of the muscles had a high percentage of Type IIa fibers. In terms of the muscle characteristic in several parts of the horse body, the forelimb muscles had a higher percentage of Type IIa fiber and a significantly lower percentage of Type IIx fiber than the hindlimb muscles. The muscle fiber type populations in the thoracic and trunk portion were similar to those in the hindlimb portion. Biochemical analysis indicated high succinate dehydrogenase activity in respiratory-related muscle and high phosphofructokinase activity in hindlimbs. We suggested that the higher percentage of Type IIa fibers in Thoroughbred racehorses is attributed to training effects. To consider further the physiological significance of each part of the body, data for the recruitment pattern of each muscle fiber type during exercise are needed. The muscle fiber properties in this study combined with the recruitment data would provide fundamental information for physiological and pathological studies in Thoroughbred horses.

  9. Muscle synergy space: learning model to create an optimal muscle synergy.

    Science.gov (United States)

    Alnajjar, Fady; Wojtara, Tytus; Kimura, Hidenori; Shimoda, Shingo

    2013-01-01

    Muscle redundancy allows the central nervous system (CNS) to choose a suitable combination of muscles from a number of options. This flexibility in muscle combinations allows for efficient behaviors to be generated in daily life. The computational mechanism of choosing muscle combinations, however, remains a long-standing challenge. One effective method of choosing muscle combinations is to create a set containing the muscle combinations of only efficient behaviors, and then to choose combinations from that set. The notion of muscle synergy, which was introduced to divide muscle activations into a lower-dimensional synergy space and time-dependent variables, is a suitable tool relevant to the discussion of this issue. The synergy space defines the suitable combinations of muscles, and time-dependent variables vary in lower-dimensional space to control behaviors. In this study, we investigated the mechanism the CNS may use to define the appropriate region and size of the synergy space when performing skilled behavior. Two indices were introduced in this study, one is the synergy stability index (SSI) that indicates the region of the synergy space, the other is the synergy coordination index (SCI) that indicates the size of the synergy space. The results on automatic posture response experiments show that SSI and SCI are positively correlated with the balance skill of the participants, and they are tunable by behavior training. These results suggest that the CNS has the ability to create optimal sets of efficient behaviors by optimizing the size of the synergy space at the appropriate region through interacting with the environment.

  10. Comparison between neurectomy and botulinum toxin A injection for denervated skeletal muscle.

    Science.gov (United States)

    Tsai, Feng-Chou; Hsieh, Ming-Shium; Chou, Chih-Ming

    2010-08-01

    Neurectomy and botulinum toxin A (BoNT-A) injection cause denervated muscle atrophy, but questions remain about their clinical utility. We investigated time-series alterations of rat muscle weight, functional deficits, signaling pathways, and microscopic structures, to gain an understanding of the clinical implications. Between 2008 and 2009, the maximal calf circumference of patients for calf reduction either by neurectomy or BoNT-A injections were recorded for study. A rat skeletal muscle model was established through repeated or dose-adjusted BoNT-A injections and neurectomy. The survival, apoptosis pathways, functional deficits, and microscopic structures were investigated using Western blot, sciatic functional index (SFI), and transmission electron microscopy (TEM), respectively. The rat muscle weight ratio of the BoNT-A group had recovered to 89.3 +/- 3.8% by week 58, but it never recovered in the neurectomy group. Muscle weight reduction by BoNT-A not only depended on the dose, but additive effects were also obtained through repeated injections. Rat SFI demonstrated rapid recovery in both groups. Molecular expressions showed a coherent and biphasic pattern. p-Akt and apoptosis-inducing factor (AIF) were upregulated significantly, with a peak at 8 weeks in the neurectomy group (p structure disruption and sarcomere discontinuity in the neurectomy and BoNT-A groups, respectively. We demonstrated that denervation induced lasting muscle weight and structural changes of different degrees. Muscle weight reduction by BoNT-A was related to frequency and dose. AIF-mediated caspase-independent apoptosis was significantly different for neurectomy and BoNT-A injection.

  11. Effects of extracts of denervated muscles on the morphology of cultured muscle cells

    NARCIS (Netherlands)

    Hooisma, J.; Krijger, J.de; Groot, D.M.G. de

    1981-01-01

    Previously tropic effects of extracts from whole chick embryos and from innervated muscles on cultured muscle cells were described. The present study demonstrated similar effects of extracts from 10-days denervated chick muscles. Extracts from innervated as well as from denervated muscles

  12. Influence of temperature on muscle recruitment and muscle function in vivo.

    Science.gov (United States)

    Rome, L C

    1990-08-01

    Temperature has a large influence on the maximum velocity of shortening (Vmax) and maximum power output of muscle (Q10 = 1.5-3). In some animals, maximum performance and maximum sustainable performance show large temperature sensitivities, because these parameters are dependent solely on mechanical power output of the muscles. The mechanics of locomotion (sarcomere length excursions and muscle-shortening velocities, V) at a given speed, however, are precisely the same at all temperatures. Animals compensate for the diminished power output of their muscles at low temperatures by compressing their recruitment order into a narrower range of locomotor speeds, that is, recruiting more muscle fibers and faster fiber types at a given speed. By examining V/Vmax, I calculate that fish at 10 degrees C must recruit 1.53-fold greater fiber cross section than at 20 degrees C. V/Vmax also appears to be an important design constraint in muscle. It sets the lowest V and the highest V over which a muscle can be used effectively. Because the Vmax of carp slow red muscle has a Q10 of 1.6 between 10 and 20 degrees C, the slow aerobic fibers can be used over a 1.6-fold greater range of swim speeds at the warmer temperature. In some species of fish, Vmax can be increased during thermal acclimation, enabling animals to swim at higher speeds.

  13. Evaluation of clinical methods for peroneal muscle testing.

    Science.gov (United States)

    Sarig-Bahat, Hilla; Krasovsky, Andrei; Sprecher, Elliot

    2013-03-01

    Manual muscle testing of the peroneal muscles is well accepted as a testing method in musculoskeletal physiotherapy for the assessment of the foot and ankle. The peroneus longus and brevis are primary evertors and secondary plantar flexors of the ankle joint. However, some international textbooks describe them as dorsi flexors, when instructing peroneal muscle testing. The identified variability raised a question whether these educational texts are reflected in the clinical field. The purposes of this study were to investigate what are the methods commonly used in the clinical field for peroneal muscle testing and to evaluate their compatibility with functional anatomy. A cross-sectional study was conducted, using an electronic questionnaire sent to 143 Israeli physiotherapists in the musculoskeletal field. The survey questioned on the anatomical location of manual resistance and the combination of motions resisted. Ninety-seven responses were received. The majority (69%) of respondents related correctly to the peronei as evertors, but asserted that resistance should be located over the dorsal aspect of the fifth metatarsus, thereby disregarding the peroneus longus. Moreover, 38% of the respondents described the peronei as dorsi flexors, rather than plantar flexors. Only 2% selected the correct method of resisting plantarflexion and eversion at the base of the first metatarsus. We consider this technique to be the most compatible with the anatomy of the peroneus longus and brevis. The Fisher-Freeman-Halton test indicated that there was a significant relationship between responses on the questions (P = 0.0253, 95% CI 0.0249-0.0257), thus justifying further correspondence analysis. The correspondence analysis found no clustering of the answers that were compatible with anatomical evidence and were applied in the correct technique, but did demonstrate a common error, resisting dorsiflexion rather than plantarflexion, which was in agreement with the described

  14. Function of skeletal muscle tissue formed after myoblast transplantation into irradiated mouse muscles.

    Science.gov (United States)

    Wernig, A; Zweyer, M; Irintchev, A

    2000-01-15

    1. Pretreatment of muscles with ionising radiation enhances tissue formation by transplanted myoblasts but little is known about the effects on muscle function. We implanted myoblasts from an expanded, male-donor-derived, culture (i28) into X-ray irradiated (16 Gy) or irradiated and damaged soleus muscles of female syngeneic mice (Balb/c). Three to 6 months later the isometric contractile properties of the muscles were studied in vitro, and donor nuclei were visualised in muscle sections with a Y chromosome-specific DNA probe. 2. Irradiated sham-injected muscles had smaller masses than untreated solei and produced less twitch and tetanic force (all by about 18 %). Injection of 106 myoblasts abolished these deficiencies and innervation appeared normal. 3. Cryodamage of irradiated solei produced muscle remnants with few (1-50) or no fibres. Additional myoblast implantation led to formation of large muscles (25 % above normal) containing numerous small-diameter fibres. Upon direct electrical stimulation, these muscles produced considerable twitch (53 % of normal) and tetanic forces (35 % of normal) but innervation was insufficient as indicated by weak nerve-evoked contractions and elevated ACh sensitivity. 4. In control experiments on irradiated muscles, reinnervation was found to be less complete after botulinum toxin paralysis than after nerve crush indicating that proliferative arrest of irradiated Schwann cells may account for the observed innervation deficits. 5. Irradiation appears to be an effective pretreatment for improving myoblast transplantation. The injected cells can even produce organised contractile tissue replacing whole muscle. However, impaired nerve regeneration limits the functional performance of the new muscle.

  15. Physical principles demonstrate that the biceps femoris muscle relative to the other hamstring muscles exerts the most force: implications for hamstring muscle strain injuries.

    Science.gov (United States)

    Dolman, Bronwyn; Verrall, Geoffrey; Reid, Iain

    2014-07-01

    Of the hamstring muscle group the biceps femoris muscle is the most commonly injured muscle in sports requiring interval sprinting. The reason for this observation is unknown. The objective of this study was to calculate the forces of all three hamstring muscles, relative to each other, during a lengthening contraction to assess for any differences that may help explain the biceps femoris predilection for injury during interval sprinting. To calculate the displacement of each individual hamstring muscle previously performed studies on cadaveric anatomical data and hamstring kinematics during sprinting were used. From these displacement calculations for each individual hamstring muscle physical principles were then used to deduce the proportion of force exerted by each individual hamstring muscle during a lengthening muscle contraction. These deductions demonstrate that the biceps femoris muscle is required to exert proportionally more force in a lengthening muscle contraction relative to the semimembranosus and semitendinosus muscles primarily as a consequence of having to lengthen over a greater distance within the same time frame. It is hypothesized that this property maybe a factor in the known observation of the increased susceptibility of the biceps femoris muscle to injury during repeated sprints where recurrent higher force is required.

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

    Directory of Open Access Journals (Sweden)

    Dean Dessem

    2011-01-01

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

  17. Muscle Satellite Cell Protein Teneurin‐4 Regulates Differentiation During Muscle Regeneration

    Science.gov (United States)

    Ishii, Kana; Suzuki, Nobuharu; Mabuchi, Yo; Ito, Naoki; Kikura, Naomi; Fukada, So‐ichiro; Okano, Hideyuki; Takeda, Shin'ichi

    2015-01-01

    Abstract Satellite cells are maintained in an undifferentiated quiescent state, but during muscle regeneration they acquire an activated stage, and initiate to proliferate and differentiate as myoblasts. The transmembrane protein teneurin‐4 (Ten‐4) is specifically expressed in the quiescent satellite cells; however, its cellular and molecular functions remain unknown. We therefore aimed to elucidate the function of Ten‐4 in muscle satellite cells. In the tibialis anterior (TA) muscle of Ten‐4‐deficient mice, the number and the size of myofibers, as well as the population of satellite cells, were reduced with/without induction of muscle regeneration. Furthermore, we found an accelerated activation of satellite cells in the regenerated Ten‐4‐deficient TA muscle. The cell culture analysis using primary satellite cells showed that Ten‐4 suppressed the progression of myogenic differentiation. Together, our findings revealed that Ten‐4 functions as a crucial player in maintaining the quiescence of muscle satellite cells. Stem Cells 2015;33:3017–3027 PMID:26013034

  18. Patients with type 2 diabetes have normal mitochondrial function in skeletal muscle

    DEFF Research Database (Denmark)

    Boushel, R; Gnaiger, E; Schjerling, P

    2007-01-01

    AIMS/HYPOTHESIS: Insulin resistance and type 2 diabetes are associated with mitochondrial dysfunction. The aim of the present study was to test the hypothesis that oxidative phosphorylation and electron transport capacity are diminished in the skeletal muscle of type 2 diabetic subjects......, as a result of a reduction in the mitochondrial content. MATERIALS AND METHODS: The O(2) flux capacity of permeabilised muscle fibres from biopsies of the quadriceps in healthy subjects (n = 8; age 58 +/- 2 years [mean+/-SEM]; BMI 28 +/- 1 kg/m(2); fasting plasma glucose 5.4 +/- 0.2 mmol/l) and patients...... with type 2 diabetes (n = 11; age 62 +/- 2 years; BMI 32 +/- 2 kg/m(2); fasting plasma glucose 9.0 +/- 0.8 mmol/l) was measured by high-resolution respirometry. RESULTS: O(2) flux expressed per mg of muscle (fresh weight) during ADP-stimulated state 3 respiration was lower (p type 2...

  19. The Promotion of a Functional Fibrosis in Skeletal Muscle with Volumetric Muscle Loss Injury Following the Transplantation of Muscle-ECM

    Science.gov (United States)

    2013-02-04

    Zou K, Boppart MD. Eccentric exercise facil- itates mesenchymal stem cell appearance in skeletal muscle. PLoS One 2012; 7:e29760. [40] Matziolis G...remaining muscle mass leading to additional improvements in functional capacity; how- ever, no study has explicitly studied these effects . The purpose of...muscles were isolated from donor Lewis rats. The tendon and fascia were removed and TA muscle decellularization was performed using an enzymatic and

  20. 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.

  1. Muscle activation during selected strength exercises in women with chronic neck muscle pain

    DEFF Research Database (Denmark)

    Andersen, Lars L; Kjaer, Michael; Andersen, Christoffer H

    2008-01-01

    selected strengthening exercises in women undergoing rehabilitation for chronic neck muscle pain (defined as a clinical diagnosis of trapezius myalgia). SUBJECTS: The subjects were 12 female workers (age=30-60 years) with a clinical diagnosis of trapezius myalgia and a mean baseline pain intensity of 5......BACKGROUND AND PURPOSE: Muscle-specific strength training has previously been shown to be effective in the rehabilitation of chronic neck muscle pain in women. The aim of this study was to determine the level of activation of the neck and shoulder muscles using surface electromyography (EMG) during...... muscle pain. Several of the strength exercises had high activation of neck and shoulder muscles in women with chronic neck pain. These exercises can be used equally in the attempt to achieve a beneficial treatment effect on chronic neck muscle pain....

  2. Muscle organizers in Drosophila: the role of persistent larval fibers in adult flight muscle development

    Science.gov (United States)

    Farrell, E. R.; Fernandes, J.; Keshishian, H.

    1996-01-01

    In many organisms muscle formation depends on specialized cells that prefigure the pattern of the musculature and serve as templates for myoblast organization and fusion. These include muscle pioneers in insects and muscle organizing cells in leech. In Drosophila, muscle founder cells have been proposed to play a similar role in organizing larval muscle development during embryogenesis. During metamorphosis in Drosophila, following histolysis of most of the larval musculature, there is a second round of myogenesis that gives rise to the adult muscles. It is not known whether muscle founder cells organize the development of these muscles. However, in the thorax specific larval muscle fibers do not histolyze at the onset of metamorphosis, but instead serve as templates for the formation of a subset of adult muscles, the dorsal longitudinal flight muscles (DLMs). Because these persistent larval muscle fibers appear to be functioning in many respects like muscle founder cells, we investigated whether they were necessary for DLM development by using a microbeam laser to ablate them singly and in combination. We found that, in the absence of the larval muscle fibers, DLMs nonetheless develop. Our results show that the persistent larval muscle fibers are not required to initiate myoblast fusion, to determine DLM identity, to locate the DLMs in the thorax, or to specify the total DLM fiber volume. However, they are required to regulate the number of DLM fibers generated. Thus, while the persistent larval muscle fibers are not obligatory for DLM fiber formation and differentiation, they are necessary to ensure the development of the correct number of fibers.

  3. Human skeletal muscle fibroblasts stimulate in vitro myogenesis and in vivo muscle regeneration.

    Science.gov (United States)

    Mackey, Abigail L; Magnan, Mélanie; Chazaud, Bénédicte; Kjaer, Michael

    2017-08-01

    Accumulation of skeletal muscle extracellular matrix is an unfavourable characteristic of many muscle diseases, muscle injury and sarcopenia. The extent of cross-talk between fibroblasts, as the source of matrix protein, and satellite cells in humans is unknown. We studied this in human muscle biopsies and cell-culture studies. We observed a strong stimulation of myogenesis by human fibroblasts in cell culture. In biopsies collected 30 days after a muscle injury protocol, fibroblast number increased to four times control levels, where fibroblasts were found to be preferentially located immediately surrounding regenerating muscle fibres. These novel findings indicate an important role for fibroblasts in supporting the regeneration of muscle fibres, potentially through direct stimulation of satellite cell differentiation and fusion, and contribute to understanding of cell-cell cross-talk during physiological and pathological muscle remodelling. Accumulation of skeletal muscle extracellular matrix is an unfavourable characteristic of many muscle diseases, muscle injury and sarcopenia. In addition to the indispensable role satellite cells play in muscle regeneration, there is emerging evidence in rodents for a regulatory influence on fibroblast activity. However, the influence of fibroblasts on satellite cells and muscle regeneration in humans is unknown. The purpose of this study was to investigate this in vitro and during in vivo regeneration in humans. Following a muscle injury protocol in young healthy men (n = 7), the number of fibroblasts (TCF7L2+), satellite cells (Pax7+), differentiating myogenic cells (myogenin+) and regenerating fibres (neonatal/embryonic myosin+) was determined from biopsy cross-sections. Fibroblasts and myogenic precursor cells (MPCs) were also isolated from human skeletal muscle (n = 4) and co-cultured using different cell ratios, with the two cell populations either in direct contact with each other or separated by a permeable

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

    Science.gov (United States)

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

    2016-01-01

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

  5. Ultrasound assessment of hamstring muscle size using posterior thigh muscle thickness.

    Science.gov (United States)

    Abe, Takashi; Loenneke, Jeremy P; Thiebaud, Robert S

    2016-05-01

    Several studies have investigated the relationship between ultrasound-measured muscle thickness (MT) and individual muscle cross-sectional area (CSA) and muscle volume (MV) in extremity and trunk muscles; however, the hamstring muscle has not been studied. The purpose of this study was to examine the relationship between posterior thigh MT by ultrasound and the muscle CSA and MV of the hamstring obtained by magnetic resonance imaging (MRI). Ten young women aged 20-31 had MT measured by ultrasound at three sites on the medial anterior (50% of thigh length; TL) and posterior (50% and 70% of TL) aspects of the thigh. On the same day, a series of continuous muscle CSA along the thigh was measured by MRI. In each slice, the anatomical CSA of the hamstring (biceps femoris, semitendinosus and semimembranosus) and quadriceps muscle was analysed, and the CSAs at 50% and 70% of TL and maximal CSA of the hamstring (CSAmax ) were determined. MV was calculated by multiplying CSA by slice thickness. A significant correlation was observed between posterior 50% MT and 50% hamstring CSA (r = 0·848, P = 0·002) and between posterior 70% MT and 70% hamstring CSA (r = 0·679, P = 0·031). Posterior 50% MT (r = 0·732, P = 0·016) and 50% MTxTL (r = 0·873, P = 0·001) were also correlated to hamstring MV. Anterior:posterior 50% thigh MT ratio was correlated to MV ratio of quadriceps and hamstring muscles (r = 0·803, P = 0·005). Our results suggest that posterior thigh MT reflects hamstring muscle CSA and MV. The anterior:posterior MT ratio may serve as a surrogate for MV ratio of quadriceps and hamstring. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  6. Accessory piriformis muscle

    Directory of Open Access Journals (Sweden)

    Sedat Develi

    2017-03-01

    Full Text Available Piriformis muscle originates from facies pelvica of sacrum and inserts on the trochanter major. It is one of the lateral rotator muscles of the hip and a landmark point in the gluteal region since n. ischiadicus descends to the thigh by passing close to the muscle. This contiguity may be associated with the irritation of the nerve which is known as piriformis syndrome. A rare anatomic variation of the muscle which observed on 74 years old male cadaver is discussed in this case report. [Cukurova Med J 2017; 42(1.000: 182-183

  7. Muscle Satellite Cell Protein Teneurin-4 Regulates Differentiation During Muscle Regeneration.

    Science.gov (United States)

    Ishii, Kana; Suzuki, Nobuharu; Mabuchi, Yo; Ito, Naoki; Kikura, Naomi; Fukada, So-Ichiro; Okano, Hideyuki; Takeda, Shin'ichi; Akazawa, Chihiro

    2015-10-01

    Satellite cells are maintained in an undifferentiated quiescent state, but during muscle regeneration they acquire an activated stage, and initiate to proliferate and differentiate as myoblasts. The transmembrane protein teneurin-4 (Ten-4) is specifically expressed in the quiescent satellite cells; however, its cellular and molecular functions remain unknown. We therefore aimed to elucidate the function of Ten-4 in muscle satellite cells. In the tibialis anterior (TA) muscle of Ten-4-deficient mice, the number and the size of myofibers, as well as the population of satellite cells, were reduced with/without induction of muscle regeneration. Furthermore, we found an accelerated activation of satellite cells in the regenerated Ten-4-deficient TA muscle. The cell culture analysis using primary satellite cells showed that Ten-4 suppressed the progression of myogenic differentiation. Together, our findings revealed that Ten-4 functions as a crucial player in maintaining the quiescence of muscle satellite cells. © 2015 The Authors STEM CELLS published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  8. 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.

  9. Extraocular muscle function testing

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003397.htm Extraocular muscle function testing To use the sharing features on this page, please enable JavaScript. Extraocular muscle function testing examines the function of the eye muscles. ...

  10. Muscle-specific expression of hypoxia-inducible factor in human skeletal muscle

    DEFF Research Database (Denmark)

    Mounier, Rémi; Pedersen, Bente Klarlund; Plomgaard, Peter

    2010-01-01

    fibres that possess unique patterns of protein and gene expression, producing different capillarization and energy metabolism systems. In this work, we analysed HIF-1alpha mRNA and protein expression related to the fibre-type composition in untrained human skeletal muscle by obtaining muscle biopsies...... from triceps brachii (characterized by a high proportion of type II fibres), from soleus (characterized by a high proportion of type I fibres) and from vastus lateralis (characterized by an equal proportion of type I and II fibres). The hypothesis was that type I muscle fibres would have lower HIF-1......alpha protein level. Interestingly, none of the HIF-1alpha target genes, like the most studied angiogenic factor involved in muscle angiogenesis, vascular endothelial growth factor (VEGF), exhibited a muscle fibre-specific-related mRNA expression at rest in normoxia. However, soleus presented...

  11. MRI appearances of the anterior fibulocalcaneus muscle: a rare anterior compartment muscle

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Bhavin [Basildon and Thurrock University Hospitals NHS Foundation Trust, Imaging Department, Essex (United Kingdom); Amiras, Dimitri [Imperial College Health Care NHS Trust, Imaging Department, London (United Kingdom)

    2015-05-01

    MRI of a 62-year-old female presenting with ankle pain demonstrated an accessory muscle within the anterior compartment of the lower leg. The muscle originated from the fibula and anterior crural septum. The tendon passed anterior to the lateral malleolus and inserted at the critical angle of Gissane on the calcaneus. This muscle was initially described in the anatomic literature by Lambert and Atsas in 2010. To our knowledge, this is the first time the MRI appearances of this muscle has been described in the radiological literature. Awareness of the fibulocalcaneal muscle is important as it may represent a cause of ankle pain. In addition, the tendon could potentially be harvested for use in reconstructive procedures. (orig.)

  12. Brain and muscle Arnt-like 1 promotes skeletal muscle regeneration through satellite cell expansion

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Somik [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Yin, Hongshan [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Department of Cardiovascular Medicine, Third Affiliated Hospital, Hebei Medical University, Shijiazhuang 050051, Hebei (China); Nam, Deokhwa [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Li, Yong [Department of Pediatric Surgery, Center for Stem Cell Research and Regenerative Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030 (United States); Ma, Ke, E-mail: kma@houstonmethodist.org [Center for Diabetes Research, Department of Medicine, Houston Methodist Research Institute, Houston, TX 77030 (United States)

    2015-02-01

    Circadian clock is an evolutionarily conserved timing mechanism governing diverse biological processes and the skeletal muscle possesses intrinsic functional clocks. Interestingly, although the essential clock transcription activator, Brain and muscle Arnt-like 1 (Bmal1), participates in maintenance of muscle mass, little is known regarding its role in muscle growth and repair. In this report, we investigate the in vivo function of Bmal1 in skeletal muscle regeneration using two muscle injury models. Bmal1 is highly up-regulated by cardiotoxin injury, and its genetic ablation significantly impairs regeneration with markedly suppressed new myofiber formation and attenuated myogenic induction. A similarly defective regenerative response is observed in Bmal1-null mice as compared to wild-type controls upon freeze injury. Lack of satellite cell expansion accounts for the regeneration defect, as Bmal1{sup −/−} mice display significantly lower satellite cell number with nearly abolished induction of the satellite cell marker, Pax7. Furthermore, satellite cell-derived primary myoblasts devoid of Bmal1 display reduced growth and proliferation ex vivo. Collectively, our results demonstrate, for the first time, that Bmal1 is an integral component of the pro-myogenic response that is required for muscle repair. This mechanism may underlie its role in preserving adult muscle mass and could be targeted therapeutically to prevent muscle-wasting diseases. - Highlights: • Bmal1 is highly inducible by muscle injury and myogenic stimuli. • Genetic ablation of Bmal1 significantly impairs muscle regeneration. • Bmal1 promotes satellite cell expansion during muscle regeneration. • Bmal1-deficient primary myoblasts display attenuated growth and proliferation.

  13. Brain and muscle Arnt-like 1 promotes skeletal muscle regeneration through satellite cell expansion

    International Nuclear Information System (INIS)

    Chatterjee, Somik; Yin, Hongshan; Nam, Deokhwa; Li, Yong; Ma, Ke

    2015-01-01

    Circadian clock is an evolutionarily conserved timing mechanism governing diverse biological processes and the skeletal muscle possesses intrinsic functional clocks. Interestingly, although the essential clock transcription activator, Brain and muscle Arnt-like 1 (Bmal1), participates in maintenance of muscle mass, little is known regarding its role in muscle growth and repair. In this report, we investigate the in vivo function of Bmal1 in skeletal muscle regeneration using two muscle injury models. Bmal1 is highly up-regulated by cardiotoxin injury, and its genetic ablation significantly impairs regeneration with markedly suppressed new myofiber formation and attenuated myogenic induction. A similarly defective regenerative response is observed in Bmal1-null mice as compared to wild-type controls upon freeze injury. Lack of satellite cell expansion accounts for the regeneration defect, as Bmal1 −/− mice display significantly lower satellite cell number with nearly abolished induction of the satellite cell marker, Pax7. Furthermore, satellite cell-derived primary myoblasts devoid of Bmal1 display reduced growth and proliferation ex vivo. Collectively, our results demonstrate, for the first time, that Bmal1 is an integral component of the pro-myogenic response that is required for muscle repair. This mechanism may underlie its role in preserving adult muscle mass and could be targeted therapeutically to prevent muscle-wasting diseases. - Highlights: • Bmal1 is highly inducible by muscle injury and myogenic stimuli. • Genetic ablation of Bmal1 significantly impairs muscle regeneration. • Bmal1 promotes satellite cell expansion during muscle regeneration. • Bmal1-deficient primary myoblasts display attenuated growth and proliferation

  14. Respiratory muscle involvement in sarcoidosis.

    Science.gov (United States)

    Schreiber, Tina; Windisch, Wolfram

    2018-07-01

    In sarcoidosis, muscle involvement is common, but mostly asymptomatic. Currently, little is known about respiratory muscle and diaphragm involvement and function in patients with sarcoidosis. Reduced inspiratory muscle strength and/or a reduced diaphragm function may contribute to exertional dyspnea, fatigue and reduced health-related quality of life. Previous studies using volitional and non-volitional tests demonstrated a reduced inspiratory muscle strength in sarcoidosis compared to control subjects, and also showed that respiratory muscle function may even be significantly impaired in a subset of patients. Areas covered: This review examines the evidence on respiratory muscle involvement and its implications in sarcoidosis with emphasis on pathogenesis, diagnosis and treatment of respiratory muscle dysfunction. The presented evidence was identified by a literature search performed in PubMed and Medline for articles about respiratory and skeletal muscle function in sarcoidosis through to January 2018. Expert commentary: Respiratory muscle involvement in sarcoidosis is an underdiagnosed condition, which may have an important impact on dyspnea and health-related quality of life. Further studies are needed to understand the etiology, pathogenesis and extent of respiratory muscle involvement in sarcoidosis.

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

    Science.gov (United States)

    Butterfield, Timothy A; Herzog, Walter

    2006-05-01

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

  16. The optimal stimulation pattern for skeletal muscle is dependent on muscle length

    NARCIS (Netherlands)

    Mela, P.; Veltink, Petrus H.; Huijing, P.A.J.B.M.; Salmons, S.; Jarvis, J.C.

    2002-01-01

    elicited muscle contraction. Such patterns, providing the desired force output with the minimum number of pulses, may reduce muscle fatigue, which has been shown to correlate to the number of pulses delivered. Applications of electrical stimulation to use muscle as a controllable biological actuator

  17. The role of the myosin ATPase activity in adaptive thermogenesis by skeletal muscle.

    Science.gov (United States)

    Cooke, Roger

    2011-03-01

    Resting skeletal muscle is a major contributor to adaptive thermogenesis, i.e., the thermogenesis that changes in response to exposure to cold or to overfeeding. The identification of the "furnace" that is responsible for increased heat generation in resting muscle has been the subject of a number of investigations. A new state of myosin, the super relaxed state (SRX), with a very slow ATP turnover rate has recently been observed in skeletal muscle (Stewart et al. in Proc Natl Acad Sci USA 107:430-435, 2010). Inhibition of the myosin ATPase activity in the SRX was suggested to be caused by binding of the myosin head to the core of the thick filament in a structural motif identified earlier by electron microscopy. To be compatible with the basal metabolic rate observed in vivo for resting muscle, most myosin heads would have to be in the SRX. Modulation of the population of this state, relative to the normal relaxed state, was proposed to be a major contributor to adaptive thermogenesis in resting muscle. Transfer of only 20% of myosin heads from the SRX into the normal relaxed state would cause muscle thermogenesis to double. Phosphorylation of the myosin regulatory light chain was shown to transfer myosin heads from the SRX into the relaxed state, which would increase thermogenesis. In particular, thermogenesis by myosin has been proposed to play a role in the dissipation of calories during overfeeding. Up-regulation of muscle thermogenesis by pharmaceuticals that target the SRX would provide new approaches to the treatment of obesity or high blood sugar levels.

  18. Effect of repeated forearm muscle cooling on the adaptation of skeletal muscle metabolism in humans

    Science.gov (United States)

    Wakabayashi, Hitoshi; Nishimura, Takayuki; Wijayanto, Titis; Watanuki, Shigeki; Tochihara, Yutaka

    2017-07-01

    This study aimed to investigate the effect of repeated cooling of forearm muscle on adaptation in skeletal muscle metabolism. It is hypothesized that repeated decreases of muscle temperature would increase the oxygen consumption in hypothermic skeletal muscle. Sixteen healthy males participated in this study. Their right forearm muscles were locally cooled to 25 °C by cooling pads attached to the skin. This local cooling was repeated eight times on separate days for eight participants (experimental group), whereas eight controls received no cold exposure. To evaluate adaptation in skeletal muscle metabolism, a local cooling test was conducted before and after the repeated cooling period. Change in oxy-hemoglobin content in the flexor digitorum at rest and during a 25-s isometric handgrip (10% maximal voluntary construction) was measured using near-infrared spectroscopy at every 2 °C reduction in forearm muscle temperature. The arterial blood flow was occluded for 15 s by upper arm cuff inflation at rest and during the isometric handgrip. The oxygen consumption in the flexor digitorum muscle was evaluated by a slope of the oxy-hemoglobin change during the arterial occlusion. In the experimental group, resting oxygen consumption in skeletal muscle did not show any difference between pre- and post-intervention, whereas muscle oxygen consumption during the isometric handgrip was significantly higher in post-intervention than in pre-test from thermoneutral baseline to 31 °C muscle temperature ( P cooling might facilitate oxidative metabolism in the skeletal muscle. In summary, skeletal muscle metabolism during submaximal isometric handgrip was facilitated after repeated local muscle cooling.

  19. Proteomics of Skeletal Muscle

    DEFF Research Database (Denmark)

    Deshmukh, Atul

    2016-01-01

    , of altered protein expressions profiles and/or their posttranslational modifications (PTMs). Mass spectrometry (MS)-based proteomics offer enormous promise for investigating the molecular mechanisms underlying skeletal muscle insulin resistance and exercise-induced adaptation; however, skeletal muscle......Skeletal muscle is the largest tissue in the human body and plays an important role in locomotion and whole body metabolism. It accounts for ~80% of insulin stimulated glucose disposal. Skeletal muscle insulin resistance, a primary feature of Type 2 diabetes, is caused by a decreased ability...... of muscle to respond to circulating insulin. Physical exercise improves insulin sensitivity and whole body metabolism and remains one of the most promising interventions for the prevention of Type 2 diabetes. Insulin resistance and exercise adaptations in skeletal muscle might be a cause, or consequence...

  20. Potential of laryngeal muscle regeneration using induced pluripotent stem cell-derived skeletal muscle cells.

    Science.gov (United States)

    Dirja, Bayu Tirta; Yoshie, Susumu; Ikeda, Masakazu; Imaizumi, Mitsuyoshi; Nakamura, Ryosuke; Otsuki, Koshi; Nomoto, Yukio; Wada, Ikuo; Hazama, Akihiro; Omori, Koichi

    2016-01-01

    Conclusion Induced pluripotent stem (iPS) cells may be a new potential cell source for laryngeal muscle regeneration in the treatment of vocal fold atrophy after recurrent laryngeal nerve paralysis. Objectives Unilateral vocal fold paralysis can lead to degeneration, atrophy, and loss of force of the thyroarytenoid muscle. At present, there are some treatments such as thyroplasty, arytenoid adduction, and vocal fold injection. However, such treatments cannot restore reduced mass of the thyroarytenoid muscle. iPS cells have been recognized as supplying a potential resource for cell transplantation. The aim of this study was to assess the effectiveness of the use of iPS cells for the regeneration of laryngeal muscle through the evaluation of both in vitro and in vivo experiments. Methods Skeletal muscle cells were generated from tdTomato-labeled iPS cells using embryoid body formation. Differentiation into skeletal muscle cells was analyzed by gene expression and immunocytochemistry. The tdTomato-labeled iPS cell-derived skeletal muscle cells were transplanted into the left atrophied thyroarytenoid muscle. To evaluate the engraftment of these cells after transplantation, immunohistochemistry was performed. Results The tdTomato-labeled iPS cells were successfully differentiated into skeletal muscle cells through an in vitro experiment. These cells survived in the atrophied thyroarytenoid muscle after transplantation.

  1. The cell nuclei of skeletal muscle cells are transcriptionally active in hibernating edible dormice

    Directory of Open Access Journals (Sweden)

    Muller Sylviane

    2009-03-01

    Full Text Available Abstract Background Skeletal muscle is able to react in a rapid, dynamic way to metabolic and mechanical stimuli. In particular, exposure to either prolonged starvation or disuse results in muscle atrophy. At variance, in hibernating animals muscle atrophy may be scarce or absent after bouts of hibernation i.e., periods of prolonged (months inactivity and food deprivation, and muscle function is fully preserved at arousal. In this study, myocytes from the quadriceps muscle of euthermic and hibernating edible dormice were investigated by a combination of morphological, morphometrical and immunocytochemical analyses at the light and electron microscopy level. The focus was on cell nuclei and mitochondria, which are highly sensitive markers of changing metabolic rate. Results Findings presented herein demonstrate that: 1 the general histology of the muscle, inclusive of muscle fibre shape and size, and the ratio of fast and slow fibre types are not affected by hibernation; 2 the fine structure of cytoplasmic and nuclear constituents is similar in euthermia and hibernation but for lipid droplets, which accumulate during lethargy; 3 during hibernation, mitochondria are larger in size with longer cristae, and 4 myonuclei maintain the same amount and distribution of transcripts and transcription factors as in euthermia. Conclusion In this study we demonstrate that skeletal muscle cells of the hibernating edible dormouse maintain their structural and functional integrity in full, even after months in the nest. A twofold explanation for that is envisaged: 1 the maintenance, during hibernation, of low-rate nuclear and mitochondrial activity counterbalancing myofibre wasting, 2 the intensive muscle stimulation (shivering during periodic arousals in the nest, which would mimic physical exercise. These two factors would prevent muscle atrophy usually occurring in mammals after prolonged starvation and/or inactivity as a consequence of prevailing catabolism

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

    Science.gov (United States)

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

    2017-07-22

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

  3. A muscle model for hybrid muscle activation

    Directory of Open Access Journals (Sweden)

    Klauer Christian

    2015-09-01

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

  4. Oxidative metabolism in muscle.

    OpenAIRE

    Ferrari, M; Binzoni, T; Quaresima, V

    1997-01-01

    Oxidative metabolism is the dominant source of energy for skeletal muscle. Near-infrared spectroscopy allows the non-invasive measurement of local oxygenation, blood flow and oxygen consumption. Although several muscle studies have been made using various near-infrared optical techniques, it is still difficult to interpret the local muscle metabolism properly. The main findings of near-infrared spectroscopy muscle studies in human physiology and clinical medicine are summarized. The advantage...

  5. Eccentric muscle challenge shows osteopontin polymorphism modulation of muscle damage.

    Science.gov (United States)

    Barfield, Whitney L; Uaesoontrachoon, Kitipong; Wu, Chung-Sheih; Lin, Stephen; Chen, Yue; Wang, Paul C; Kanaan, Yasmine; Bond, Vernon; Hoffman, Eric P

    2014-08-01

    A promoter polymorphism of the osteopontin (OPN) gene (rs28357094) has been associated with multiple inflammatory states, severity of Duchenne muscular dystrophy (DMD) and muscle size in healthy young adults. We sought to define the mechanism of action of the polymorphism, using allele-specific in vitro reporter assays in muscle cells, and a genotype-stratified intervention in healthy controls. In vitro reporter constructs showed the G allele to respond to estrogen treatment, whereas the T allele showed no transcriptional response. Young adult volunteers (n = 187) were enrolled into a baseline study, and subjects with specific rs28357094 genotypes enrolled into an eccentric muscle challenge intervention [n = 3 TT; n = 3 GG/GT (dominant inheritance model)]. Female volunteers carrying the G allele showed significantly greater inflammation and increased muscle volume change as determined by magnetic resonance imaging T1- and T2-weighted images after eccentric challenge, as well as greater decrement in biceps muscle force. Our data suggest a model where the G allele enables enhanced activities of upstream enhancer elements due to loss of Sp1 binding at the polymorphic site. This results in significantly greater expression of the pro-inflammatory OPN cytokine during tissue remodeling in response to challenge in G allele carriers, promoting muscle hypertrophy in normal females, but increased damage in DMD patients. © The Author 2014. Published by Oxford University Press.

  6. Your Muscles

    Science.gov (United States)

    ... and you need to throw up. The muscles push the food back out of the stomach so it comes up ... body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren't as large, but they are capable ...

  7. Quantitative estimation of muscle fatigue using surface electromyography during static muscle contraction.

    Science.gov (United States)

    Soo, Yewguan; Sugi, Masao; Nishino, Masataka; Yokoi, Hiroshi; Arai, Tamio; Kato, Ryu; Nakamura, Tatsuhiro; Ota, Jun

    2009-01-01

    Muscle fatigue is commonly associated with the musculoskeletal disorder problem. Previously, various techniques were proposed to index the muscle fatigue from electromyography signal. However, quantitative measurement is still difficult to achieve. This study aimed at proposing a method to estimate the degree of muscle fatigue quantitatively. A fatigue model was first constructed using handgrip dynamometer by conducting a series of static contraction tasks. Then the degree muscle fatigue can be estimated from electromyography signal with reasonable accuracy. The error of the estimated muscle fatigue was less than 10% MVC and no significant difference was found between the estimated value and the one measured using force sensor. Although the results were promising, there were still some limitations that need to be overcome in future study.

  8. Association of low back pain with muscle stiffness and muscle mass of the lumbar back muscles, and sagittal spinal alignment in young and middle-aged medical workers.

    Science.gov (United States)

    Masaki, Mitsuhiro; Aoyama, Tomoki; Murakami, Takashi; Yanase, Ko; Ji, Xiang; Tateuchi, Hiroshige; Ichihashi, Noriaki

    2017-11-01

    Muscle stiffness of the lumbar back muscles in low back pain (LBP) patients has not been clearly elucidated because quantitative assessment of the stiffness of individual muscles was conventionally difficult. This study aimed to examine the association of LBP with muscle stiffness assessed using ultrasonic shear wave elastography (SWE) and muscle mass of the lumbar back muscle, and spinal alignment in young and middle-aged medical workers. The study comprised 23 asymptomatic medical workers [control (CTR) group] and 9 medical workers with LBP (LBP group). Muscle stiffness and mass of the lumbar back muscles (lumbar erector spinae, multifidus, and quadratus lumborum) in the prone position were measured using ultrasonic SWE. Sagittal spinal alignment in the standing and prone positions was measured using a Spinal Mouse. The association with LBP was investigated by multiple logistic regression analysis with a forward selection method. The analysis was conducted using the shear elastic modulus and muscle thickness of the lumbar back muscles, and spinal alignment, age, body height, body weight, and sex as independent variables. Multiple logistic regression analysis showed that muscle stiffness of the lumbar multifidus muscle and body height were significant and independent determinants of LBP, but that muscle mass and spinal alignment were not. Muscle stiffness of the lumbar multifidus muscle in the LBP group was significantly higher than that in the CTR group. The results of this study suggest that LBP is associated with muscle stiffness of the lumbar multifidus muscle in young and middle-aged medical workers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Muscles, exercise and obesity

    DEFF Research Database (Denmark)

    Pedersen, Bente K; Febbraio, Mark A

    2012-01-01

    During the past decade, skeletal muscle has been identified as a secretory organ. Accordingly, we have suggested that cytokines and other peptides that are produced, expressed and released by muscle fibres and exert either autocrine, paracrine or endocrine effects should be classified as myokines....... The finding that the muscle secretome consists of several hundred secreted peptides provides a conceptual basis and a whole new paradigm for understanding how muscles communicate with other organs, such as adipose tissue, liver, pancreas, bones and brain. However, some myokines exert their effects within...... the muscle itself. Thus, myostatin, LIF, IL-6 and IL-7 are involved in muscle hypertrophy and myogenesis, whereas BDNF and IL-6 are involved in AMPK-mediated fat oxidation. IL-6 also appears to have systemic effects on the liver, adipose tissue and the immune system, and mediates crosstalk between intestinal...

  10. Vitamin D and muscle trophicity.

    Science.gov (United States)

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

    2017-05-01

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

  11. MRI appearance of muscle denervation

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-15

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

  12. Observational Study on the Occurrence of Muscle Spindles in Human Digastric and Mylohyoideus Muscles

    Directory of Open Access Journals (Sweden)

    Daniele Saverino

    2014-01-01

    Full Text Available Although the occurrence of muscle spindles (MS is quite high in most skeletal muscles of humans, few MS, or even absence, have been reported in digastric and mylohyoideus muscles. Even if this condition is generally accepted and quoted in many papers and books, observational studies are scarce and based on histological sections of a low number of specimens. The aim of the present study is to confirm previous data, assessing MS number in a sample of digastric and mylohyoideus muscles. We investigated 11 digastric and 6 mylohyoideus muscles from 13 donors. Muscle samples were embedded in paraffin wax, cross-sectioned in a rostrocaudal direction, and stained using haematoxylin-eosin. A mean of 5.1 ± 1.1 (range 3–7 MS was found in digastric muscles and mean of 0.5 ± 0.8 (range 0–2 in mylohyoideus muscles. A significant difference (P<0.001 was found with the control sample, confirming the correctness of the histological procedure. Our results support general belief that the absolute number of spindles is sparse in digastric and mylohyoideus muscles. External forces, such as food resistance during chewing or gravity, do not counteract jaw-opening muscles. It is conceivable that this condition gives them a limited proprioceptive importance and a reduced need for having specific receptors as MS.

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

    Science.gov (United States)

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

    2010-11-01

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

  14. Muscle Fatigue in the Temporal and Masseter Muscles in Patients with Temporomandibular Dysfunction

    Directory of Open Access Journals (Sweden)

    Krzysztof Woźniak

    2015-01-01

    Full Text Available The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD. Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97 participated in this study. Electromyographical (EMG recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany. Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF% revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P<0.0000. The study showed an increase in the muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction.

  15. Muscle activity of leg muscles during unipedal stance on therapy devices with different stability properties.

    Science.gov (United States)

    Wolburg, Thomas; Rapp, Walter; Rieger, Jochen; Horstmann, Thomas

    2016-01-01

    To test the hypotheses that less stable therapy devices require greater muscle activity and that lower leg muscles will have greater increases in muscle activity with less stable therapy devices than upper leg muscles. Cross-sectional laboratory study. Laboratory setting. Twenty-five healthy subjects. Electromyographic activity of four lower (gastrocnemius medialis, soleus, tibialis anterior, peroneus longus) and four upper leg muscles (vastus medialis and lateralis, biceps femoris, semitendinosus) during unipedal quiet barefoot stance on the dominant leg on a flat rigid surface and on five therapy devices with varying stability properties. Muscle activity during unipedal stance differed significantly between therapy devices (P < 0.001). The order from lowest to highest relative muscle activity matched the order from most to least stable therapy device. There was no significant interaction between muscle location (lower versus upper leg) and therapy device (P = 0.985). Magnitudes of additional relative muscle activity for the respective therapy devices differed substantially among lower extremity muscles. The therapy devices offer a progressive increase in training intensity, and thus may be useful for incremental training programs in physiotherapeutic practice and sports training programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Tbx15 controls skeletal muscle fibre-type determination and muscle metabolism

    Science.gov (United States)

    Lee, Kevin Y.; Singh, Manvendra K.; Ussar, Siegfried; Wetzel, Petra; Hirshman, Michael F.; Goodyear, Laurie J.; Kispert, Andreas; Kahn, C. Ronald

    2015-01-01

    Skeletal muscle is composed of both slow-twitch oxidative myofibers and fast-twitch glycolytic myofibers that differentially impact muscle metabolism, function and eventually whole-body physiology. Here we show that the mesodermal transcription factor T-box 15 (Tbx15) is highly and specifically expressed in glycolytic myofibers. Ablation of Tbx15 in vivo leads to a decrease in muscle size due to a decrease in the number of glycolytic fibres, associated with a small increase in the number of oxidative fibres. This shift in fibre composition results in muscles with slower myofiber contraction and relaxation, and also decreases whole-body oxygen consumption, reduces spontaneous activity, increases adiposity and glucose intolerance. Mechanistically, ablation of Tbx15 leads to activation of AMPK signalling and a decrease in Igf2 expression. Thus, Tbx15 is one of a limited number of transcription factors to be identified with a critical role in regulating glycolytic fibre identity and muscle metabolism. PMID:26299309

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

    Science.gov (United States)

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

    2014-01-01

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

  18. Lean muscle volume of the thigh has a stronger relationship with muscle power than muscle strength in women with knee osteoarthritis.

    Science.gov (United States)

    Davison, Michael J; Maly, Monica R; Keir, Peter J; Hapuhennedige, Sandani M; Kron, Amie T; Adachi, Jonathan D; Beattie, Karen A

    2017-01-01

    Thigh lean muscle and intramuscular fat have been implicated in the impairment of physical function observed in people with knee osteoarthritis. We investigated the relationships of quadriceps and hamstrings intramuscular fat fraction and lean muscle volume with muscle power and strength, controlling for neuromuscular activation, and physical performance in women with knee OA. Women (n=20) 55years or older with symptomatic, radiographic knee osteoarthritis underwent a 3.0T magnetic resonance imaging scan of the thigh of their most symptomatic knee. Axial fat-separated images were analyzed using software to quantify intramuscular fat and lean muscle volumes of the quadriceps and hamstrings. To quantify strength and power of the knee extensors and flexors, participants performed maximum voluntary isometric contraction and isotonic knee extensions and flexions, respectively. Electromyography of the quadriceps and hamstrings was measured. Participants also completed five physical performance tests. Quadriceps and hamstrings lean muscle volumes were related to isotonic knee extensor (B=0.624; p=0.017) and flexor (B=1.518; p=0.032) power, but not knee extensor (B=0.001; p=0.615) or flexor (B=0.001; p=0.564) isometric strength. Intramuscular fat fractions were not related to isotonic knee extensor or flexor power, nor isometric strength. No relationships were found between intramuscular fat or lean muscle volume and physical performance. Muscle power may be more sensitive than strength to lean muscle mass in women with knee osteoarthritis. Thigh lean muscle mass, but neither intramuscular nor intermuscular fat, is related to knee extensor and flexor power in women with knee osteoarthritis. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-01-01

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

  20. Central projections and entries of capsaicin-sensitive muscle afferents.

    Science.gov (United States)

    Della Torre, G; Lucchi, M L; Brunetti, O; Pettorossi, V E; Clavenzani, P; Bortolami, R

    1996-03-25

    The entry pathway and central distribution of A delta and C muscle afferents within the central nervous system (CNS) were investigated by combining electron microscopy and electrophysiological analysis after intramuscular injection of capsaicin. The drug was injected into the rat lateral gastrocnemius (LG) and extraocular (EO) muscles. The compound action potentials of LG nerve and the evoked field potentials recorded in semilunar ganglion showed an immediate and permanent reduction in A delta and C components. The morphological data revealed degenerating unmyelinated axons and terminals in the inner sublamina II and in the border of laminae I-II of the dorsal horn at L4-L5 and C1-C2 (subnucleus caudalis trigemini) spinal cord segments. Most degenerating terminals were the central bouton (C) of type I and II synaptic glomeruli. Furthermore, degenerating peripheral axonal endings (V2) presynaptic to normal C were found. Since V2 were previously found degenerated after cutting the oculomotor nerve (ON) or L4 ventral root, we conclude that some A delta and C afferents from LG and EO muscles entering the CNS by ON or ventral roots make axoaxonic synapses on other primary afferents to promote an afferent control of sensory input.

  1. Biceps brachii muscle oxygenation in electrical muscle stimulation.

    Science.gov (United States)

    Muthalib, Makii; Jubeau, Marc; Millet, Guillaume Y; Maffiuletti, Nicola A; Ferrari, Marco; Nosaka, Kazunori

    2010-09-01

    The purpose of this study was to compare between electrical muscle stimulation (EMS) and maximal voluntary (VOL) isometric contractions of the elbow flexors for changes in biceps brachii muscle oxygenation (tissue oxygenation index, TOI) and haemodynamics (total haemoglobin volume, tHb = oxygenated-Hb + deoxygenated-Hb) determined by near-infrared spectroscopy (NIRS). The biceps brachii muscle of 10 healthy men (23-39 years) was electrically stimulated at high frequency (75 Hz) via surface electrodes to evoke 50 intermittent (4-s contraction, 15-s relaxation) isometric contractions at maximum tolerated current level (EMS session). The contralateral arm performed 50 intermittent (4-s contraction, 15-s relaxation) maximal voluntary isometric contractions (VOL session) in a counterbalanced order separated by 2-3 weeks. Results indicated that although the torque produced during EMS was approximately 50% of VOL (P<0.05), there was no significant difference in the changes in TOI amplitude or TOI slope between EMS and VOL over the 50 contractions. However, the TOI amplitude divided by peak torque was approximately 50% lower for EMS than VOL (P<0.05), which indicates EMS was less efficient than VOL. This seems likely because of the difference in the muscles involved in the force production between conditions. Mean decrease in tHb amplitude during the contraction phases was significantly (P<0.05) greater for EMS than VOL from the 10th contraction onwards, suggesting that the muscle blood volume was lower in EMS than VOL. It is concluded that local oxygen demand of the biceps brachii sampled by NIRS is similar between VOL and EMS.

  2. Platelet-Derived Growth Factor BB Influences Muscle Regeneration in Duchenne Muscle Dystrophy.

    Science.gov (United States)

    Piñol-Jurado, Patricia; Gallardo, Eduard; de Luna, Noemi; Suárez-Calvet, Xavier; Sánchez-Riera, Carles; Fernández-Simón, Esther; Gomis, Clara; Illa, Isabel; Díaz-Manera, Jordi

    2017-08-01

    Duchenne muscular dystrophy (DMD) is characterized by a progressive loss of muscle fibers, and their substitution by fibrotic and adipose tissue. Many factors contribute to this process, but the molecular pathways related to regeneration and degeneration of muscle are not completely known. Platelet-derived growth factor (PDGF)-BB belongs to a family of growth factors that regulate proliferation, migration, and differentiation of mesenchymal cells. The role of PDGF-BB in muscle regeneration in humans has not been studied. We analyzed the expression of PDGF-BB in muscle biopsy samples from controls and patients with DMD. We performed in vitro experiments to understand the effects of PDGF-BB on myoblasts involved in the pathophysiology of muscular dystrophies and confirmed our results in vivo by treating the mdx murine model of DMD with repeated i.m. injections of PDGF-BB. We observed that regenerating and necrotic muscle fibers in muscle biopsy samples from DMD patients expressed PDGF-BB. In vitro, PDGF-BB attracted myoblasts and activated their proliferation. Analysis of muscles from the animals treated with PDGF-BB showed an increased population of satellite cells and an increase in the number of regenerative fibers, with a reduction in inflammatory infiltrates, compared with those in vehicle-treated mice. Based on our results, PDGF-BB may play a protective role in muscular dystrophies by enhancing muscle regeneration through activation of satellite cell proliferation and migration. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  3. Modelling of pneumatic muscle actuator using Hill's model with different approximations of static characteristics of artificial muscle

    Directory of Open Access Journals (Sweden)

    Piteľ Ján

    2016-01-01

    Full Text Available For modelling and simulation of pneumatic muscle actuators the mathematical dependence of the muscle force on the muscle contraction at different pressures in the muscles is necessary to know. For this purpose the static characteristics of the pneumatic artificial muscle type FESTO MAS-20-250N used in the experiments were approximated. In the paper there are shown some simulation results of the pneumatic muscle actuator dynamics using modified Hill's muscle model, in which four different approximations of static characteristics of artificial muscle were used.

  4. Triceps brachii muscle reconstruction with a latissimus dorsi muscle flap in a dog.

    Science.gov (United States)

    Pavletic, Michael M; Kalis, Russell; Tribou, Patricia; Mouser, Pam J

    2015-01-15

    A 6-year-old spayed female Border Collie was examined for a severe deformity of the right forelimb. Three months prior to examination, the patient awkwardly fell off the couch and became acutely lame in the right forelimb, progressing to non-weight bearing over the following 72 hours. On physical examination, the dog carried the limb caudally against the thoracic wall, with the shoulder flexed and elbow in extension. The right triceps brachii muscle was atrophied and contracted, resulting in a resistant tension band effect that precluded manipulation of the right elbow joint. The physical changes in the triceps muscle were considered the primary cause of the patient's loss of limb function. Surgical treatment by means of elevation and transposition of the ipsilateral latissimus dorsi muscle was performed. The exposed triceps brachii muscles were transected 3 cm proximal to the tendons of insertion. Via a separate incision, the right latissimus dorsi muscle was elevated and tunneled subcutaneously beneath the interposing skin between the 2 surgical incisions. The muscle was then positioned and sutured to the proximal and distal borders of the divided triceps muscle group. Two weeks later, physical therapy was initiated. After 2 months, the patient regularly walked on the limb most of the time (9/10 steps). The surgical procedure for elevation and transposition of the latissimus dorsi muscle was relatively simple to perform. Physical therapy was an essential component to achieving the successful functional outcome in this case. This technique may be considered for treatment of similar patients in which the triceps muscle group is severely compromised.

  5. Muscle protein analysis. II. Two-dimensional electrophoresis of normal and diseased human skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Giometti, C.S. (Argonne National Lab., IL); Barany, M.; Danon, M.J.; Anderson, N.G.

    1980-07-01

    High-resolution two-dimensional electrophoresis was used to analyze the major proteins of normal and pathological human-muscle samples. The normal human-muscle pattern contains four myosin light chains: three that co-migrate with the myosin light chains from rabbit fast muscle (extensor digitorum longus), and one that co-migrates with the light chain 2 from rabbit slow muscle (soleus). Of seven Duchenne muscular dystrophy samples, four yielded patterns with decreased amounts of actin and myosin relative to normal muscle, while three samples gave patterns comparable to that for normal muscle. Six samples from patients with myotonic dystrophy also gave normal patterns. In nemaline rod myopathy, in contrast, the pattern was deficient in two of the fast-type myosin light chains.

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

    DEFF Research Database (Denmark)

    Nielsen, Søren; Scheele, Camilla; Yfanti, Christina

    2010-01-01

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

  7. New twist on artificial muscles.

    Science.gov (United States)

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

    2016-10-18

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

  8. Changes in muscle strength and morphology after muscle unloading in Special Forces missions

    DEFF Research Database (Denmark)

    Thorlund, J B; Jakobsen, O; Madsen, T

    2011-01-01

    The purpose of the present study was to determine the changes in maximal muscle strength, rapid force capacity, jumping performance and muscle morphology following a Special Forces military operation involving 8 days of muscle unloading. Nine male Special Forces soldiers were tested before (pre) ...

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

    Science.gov (United States)

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

    2015-05-01

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

  10. Intramuscular temperature modulates glutamate-evoked masseter muscle pain intensity in humans.

    Science.gov (United States)

    Sato, Hitoshi; Castrillon, Eduardo E; Cairns, Brian E; Bendixen, Karina H; Wang, Kelun; Nakagawa, Taneaki; Wajima, Koichi; Svensson, Peter

    2015-01-01

    To determine whether glutamate-evoked jaw muscle pain is altered by the temperature of the solution injected. Sixteen healthy volunteers participated and received injections of hot (48°C), neutral (36°C), or cold (3°C) solutions (0.5 mL) of glutamate or isotonic saline into the masseter muscle. Pain intensity was assessed with an electronic visual analog scale (eVAS). Numeric rating scale (NRS) scores of unpleasantness and temperature perception, pain-drawing areas, and pressure pain thresholds (PPTs) were also measured. Participants filled out the McGill Pain Questionnaire (MPQ). Two-way or three-way repeated measures ANOVA were used for data analyses. Injection of hot glutamate and cold glutamate solutions significantly increased and decreased, respectively, the peak pain intensity compared with injection of neutral glutamate solution. The duration of glutamate-evoked pain was significantly longer when hot glutamate was injected than when cold glutamate was injected. No significant effect of temperature on pain intensity was observed when isotonic saline was injected. No effect of solution temperature was detected on unpleasantness, heat perception, cold perception, area of pain drawings, or PPTs. There was a significantly greater use of the "numb" term in the MPQ to describe the injection of cold solutions compared to the injection of both neutral and hot solutions. Glutamate-evoked jaw muscle pain was significantly altered by the temperature of the injection solution. Although temperature perception in the jaw muscle is poor, pain intensity is increased when the muscle tissue temperature is elevated.

  11. Effects of experimental muscle pain on muscle activity and co-ordination during static and dynamic motor function.

    Science.gov (United States)

    Graven-Nielsen, T; Svensson, P; Arendt-Nielsen, L

    1997-04-01

    The relation between muscle pain, muscle activity, and muscle co-ordination is still controversial. The present human study investigates the influence of experimental muscle pain on resting, static, and dynamic muscle activity. In the resting and static experiments, the electromyography (EMG) activity and the contraction force of m. tibialis anterior were assessed before and after injection of 0.5 ml hypertonic saline (5%) into the same muscle. In the dynamic experiment, injections of 0.5 ml hypertonic saline (5%) were performed into either m. tibialis anterior (TA) or m. gastrocnemius (GA) and the muscle activity and co-ordination were investigated during gait on a treadmill by EMG recordings from m. TA and m. GA. At rest no evidence of EMG hyperactivity was found during muscle pain. The maximal voluntary contraction (MVC) during muscle pain was significantly lower than the control condition (P Fibromyalgia and Myofascial Pain. Elsevier, Amsterdam, 1993, pp. 311-327.) which predicts increased activity of antagonistic muscle and decreased activity of agonistic muscle during experimental and clinical muscle pain.

  12. How the condition of occlusal support affects the back muscle force and masticatory muscle activity?

    OpenAIRE

    石岡, 克; 河野, 正司; Ishioka, Masaru; Kohno, Shoji

    2002-01-01

    This study was conducted to determine how the condition of occlusal support affects the back muscle force and masticatory muscle activity. Two groups of subjects were enlisted: sport-trained group and normal group. While electrodes of the electromyography (EMG) were attached to the surface of the masticatory muscles, each subject's back muscle force was recorded during upper body stretching using a back muscle force-measuring device. The task was performed under four different occlusal suppor...

  13. Importance of contraction history on muscle force of porcine urinary bladder smooth muscle.

    Science.gov (United States)

    Menzel, Robin; Böl, Markus; Siebert, Tobias

    2017-02-01

    The purpose of this study was to provide a comprehensive dataset of porcine urinary bladder smooth muscle properties. Particularly, the history dependence of force production, namely force depression (FD) following shortening and force enhancement (FE) following stretch, was analysed. During active micturition, the circumference of the urinary bladder changes enormously. Thus, FD might be an important phenomenon during smooth muscle contraction. Electrically stimulated, intact urinary bladder strips from pigs (n = 10) were suspended in an aerated-filled organ bath, and different isometric, isotonic, and isokinetic contraction protocols were performed to determine the force-length and the force-velocity relation. FD and FE were assessed in concentric and eccentric contractions with different ramp lengths and ramp velocities. Bladder smooth muscles exhibit considerable amounts of FD and FE. The amount of FD increased significantly with ramp length, while FE did not change. However, FE and FD were independent of ramp velocity. The results imply that smooth muscle bladder strips exhibit similar muscle properties and history-dependent behaviour compared to striated muscles. The provided dataset of muscle properties is important for bladder modelling as well as for the analyses and interpretation of dynamic bladder filling and voiding.

  14. Direct optical activation of skeletal muscle fibres efficiently controls muscle contraction and attenuates denervation atrophy.

    Science.gov (United States)

    Magown, Philippe; Shettar, Basavaraj; Zhang, Ying; Rafuse, Victor F

    2015-10-13

    Neural prostheses can restore meaningful function to paralysed muscles by electrically stimulating innervating motor axons, but fail when muscles are completely denervated, as seen in amyotrophic lateral sclerosis, or after a peripheral nerve or spinal cord injury. Here we show that channelrhodopsin-2 is expressed within the sarcolemma and T-tubules of skeletal muscle fibres in transgenic mice. This expression pattern allows for optical control of muscle contraction with comparable forces to nerve stimulation. Force can be controlled by varying light pulse intensity, duration or frequency. Light-stimulated muscle fibres depolarize proportionally to light intensity and duration. Denervated triceps surae muscles transcutaneously stimulated optically on a daily basis for 10 days show a significant attenuation in atrophy resulting in significantly greater contractile forces compared with chronically denervated muscles. Together, this study shows that channelrhodopsin-2/H134R can be used to restore function to permanently denervated muscles and reduce pathophysiological changes associated with denervation pathologies.

  15. Spot light on skeletal muscles: optogenetic stimulation to understand and restore skeletal muscle function.

    Science.gov (United States)

    van Bremen, Tobias; Send, Thorsten; Sasse, Philipp; Bruegmann, Tobias

    2017-08-01

    Damage of peripheral nerves results in paralysis of skeletal muscle. Currently, the only treatment option to restore proper function is electrical stimulation of the innervating nerve or of the skeletal muscles directly. However this approach has low spatial and temporal precision leading to co-activation of antagonistic muscles and lacks cell-type selectivity resulting in pain or discomfort by stimulation of sensible nerves. In contrast to electrical stimulation, optogenetic methods enable spatially confined and cell-type selective stimulation of cells expressing the light sensitive channel Channelrhodopsin-2 with precise temporal control over the membrane potential. Herein we summarize the current knowledge about the use of this technology to control skeletal muscle function with the focus on the direct, non-neuronal stimulation of muscle fibers. The high temporal flexibility of using light pulses allows new stimulation patterns to investigate skeletal muscle physiology. Furthermore, the high spatial precision of focused illumination was shown to be beneficial for selective stimulation of distinct nearby muscle groups. Finally, the cell-type specific expression of the light-sensitive effector proteins in muscle fibers will allow pain-free stimulation and open new options for clinical treatments. Therefore, we believe that direct optogenetic stimulation of skeletal muscles is a very potent method for basic scientists that also harbors several distinct advantages over electrical stimulation to be considered for clinical use in the future.

  16. Modelling of pneumatic muscle actuator using Hill's model with different approximations of static characteristics of artificial muscle

    OpenAIRE

    Piteľ Ján; Tóthová Mária

    2016-01-01

    For modelling and simulation of pneumatic muscle actuators the mathematical dependence of the muscle force on the muscle contraction at different pressures in the muscles is necessary to know. For this purpose the static characteristics of the pneumatic artificial muscle type FESTO MAS-20-250N used in the experiments were approximated. In the paper there are shown some simulation results of the pneumatic muscle actuator dynamics using modified Hill's muscle model, in which four different appr...

  17. Local depletion of glycogen with supramaximal exercise in human skeletal muscle fibres.

    Science.gov (United States)

    Gejl, Kasper D; Ørtenblad, Niels; Andersson, Erik; Plomgaard, Peter; Holmberg, Hans-Christer; Nielsen, Joachim

    2017-05-01

    Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion. Skeletal muscle glycogen is heterogeneously distributed in three separated compartments (intramyofibrillar, intermyofibrillar and subsarcolemmal). Although only constituting 3-13% of the total glycogen volume, the availability of intramyofibrillar glycogen is of particular importance to muscle function. The present study aimed to investigate the depletion of these three subcellular glycogen compartments during repeated supramaximal exercise in elite athletes. Ten elite cross-country skiers (aged 25 ± 4 years, V̇O2 max : 65 ± 4 ml kg -1  min -1 ; mean ± SD) performed four ∼4 min supramaximal sprint time trials (STT 1-4) with 45 min of recovery. The subcellular glycogen volumes in musculus triceps brachii were quantified from electron microscopy images before and after both STT 1 and 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type 1 fibres [-52%; (-89:-15%)] than type 2 fibres [-15% (-52:22%)] (P = 0.02), whereas the depletion of intermyofibrillar glycogen [main effect: -19% (-33:0%), P = 0.006] and subsarcolemmal glycogen [main effect: -35% (-66:0%), P = 0.03] was similar between fibre types. By contrast, only intermyofibrillar glycogen volume was significantly reduced during STT 4, in both fibre types [main effect: -31% (-50:-11%), P = 0

  18. Muscle insulin sensitivity and glucose metabolism are controlled by the intrinsic muscle clock

    DEFF Research Database (Denmark)

    Dyar, Kenneth A.; Ciciliot, Stefano; Wright, Lauren E.

    2014-01-01

    Circadian rhythms control metabolism and energy homeostasis, but the role of the skeletal muscle clock has never been explored. We generated conditional and inducible mouse lines with muscle-specific ablation of the core clock gene Bmal1. Skeletal muscles from these mice showed impaired insulin-s...

  19. Muscle fibre capillarization is a critical factor in muscle fibre hypertrophy during resistance exercise training in older men.

    Science.gov (United States)

    Snijders, Tim; Nederveen, Joshua P; Joanisse, Sophie; Leenders, Marika; Verdijk, Lex B; van Loon, Luc J C; Parise, Gianni

    2017-04-01

    Adequate muscle fibre perfusion is critical for the maintenance of muscle mass; it is essential in the rapid delivery of oxygen, nutrients and growth factors to the muscle, stimulating muscle fibre growth. Muscle fibre capillarization is known to decrease substantially with advancing age. However, whether (relative) low muscle fibre capillarization negatively impacts the muscle hypertrophic response following resistance exercise training in older adults is unknown. Twenty-two healthy older men (71 ± 1 years) performed 24 weeks of progressive resistance type exercise training. To assess the change in muscle fibre characteristics, percutaneous biopsies from the vastus lateralis muscle were taken before and following 12 and 24 weeks of the intervention programme. A comparison was made between participants who had a relatively low type II muscle fibre capillary-to-fibre perimeter exchange index (CFPE; LOW group) and high type II muscle fibre CFPE (HIGH group) at baseline. Type I and type II muscle fibre size, satellite cell, capillary content and distance between satellite cells to the nearest capillary were determined by immunohistochemistry. Overall, type II muscle fibre size (from 5150 ± 234 to 6719 ± 446 µm 2 , P muscle fibre, P muscle fibre capillarization, whereas muscle fibre size (from 5170 ± 390 to 7133 ± 314 µm 2 , P muscle fibre, P muscle fibre capillarization were observed in response to 12 and 24 weeks of resistance exercise training in both the LOW and HIGH group. Type II muscle fibre capillarization at baseline may be a critical factor for allowing muscle fibre hypertrophy to occur during prolonged resistance exercise training in older men. © 2016 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  20. Influence of different types of carbon nanotubes on muscle cell response

    Energy Technology Data Exchange (ETDEWEB)

    Fraczek-Szczypta, Aneta, E-mail: afraczek@agh.edu.pl [Department of Biomaterials, Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Menaszek, Elzbieta [Department of Cytobiology, Collegium Medicum, Jagiellonian University, Medyczna 9, 30-068 Krakow (Poland); Blazewicz, Stanislaw [Department of Biomaterials, Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland); Adu, Jimi; Shevchenko, Ross [Pharmidex Pharmaceutical Services, 72 New Bond Street, Mayfair London, W1S 1RR (United Kingdom); Syeda, Tahmina Bahar; Misra, Anil; Alavijeh, Mohammad [School of Pharmacy and Biomolecular Sciences, Huxley Building, University of Brighton, Brighton, BN2 4GJ (United Kingdom)

    2015-01-01

    The aim of this study was to evaluate the impact of multi-walled carbon nanotubes (MWCNTs), before and after chemical surface functionalization on muscle cell response in vitro and in vivo conditions. Prior to biological tests the surface physicochemical properties of the carbon nanotubes (CNTs) deposited on a polymer membrane were investigated. To 'evaluate microstructure and structure of CNTs scanning electron microscopy (SEM) and Fourier transformation infrared spectroscopy (FTIR) were used. During in vitro study CNTs deposited on polymer membrane were contacted directly with myoblast cells, and after 7 days of culture cytotoxicity of samples was analyzed. Moreover, cell morphology in contact with CNTs was observed using SEM and fluorescence microscopy. The cytotoxicity of CNTs modified in a different way was comparable and significantly lower in comparison with pure polymer membrane. Microscopy analysis of cultured myoblasts confirms intense cell proliferation of all investigated samples with CNTs while for two kinds of CNTs myoblasts' differentiation into myotubes was observed. Histochemical reactions for the activity of enzymes such as acid phosphatase, cytochrome C oxidase, and non-specific esterase allowed the analysis of the extent of inflammation, degree of regeneration process of the muscle fibers resulting from the presence of the satellite cells and the neuromuscular junction on muscle fibers in contact with CNTs after implantation of CNTs into gluteal muscle of rat.

  1. Muscle-bone Interactions During Fracture Healing

    Science.gov (United States)

    2015-03-01

    muscle resection, isotopic or heterotopic minced muscle implants were placed immediately adjacent to the periosteum. Their control groups consisted of...interacting with surrounding muscle. Addition- ally, Utvag et al. showed that significant muscle injury and ab- sence of muscle by resection, or by traumatic

  2. Biomarkers of mitochondrial content in skeletal muscle of healthy young human subjects

    DEFF Research Database (Denmark)

    Larsen, Steen; Nielsen, Joachim; Hansen, Christina Neigaard

    2012-01-01

    Key points  Several biochemical measures of mitochondrial components are used as biomarkers of mitochondrial content and muscle oxidative capacity. However, no studies have validated these surrogates against a morphological measure of mitochondrial content in human subjects.  The most commonly used...... markers (citrate synthase activity, cardiolipin content, mitochondrial DNA content (mtDNA), complex I-V protein, and complex I-IV activity) were correlated with a measure of mitochondrial content (transmission electron microscopy) and muscle oxidative capacity (respiration in permeabilized fibres......).  Cardiolipin content followed by citrate synthase activity and complex I activity were the biomarkers showing the strongest association with mitochondrial content.  mtDNA was found to be a poor biomarker of mitochondrial content.  Complex IV activity was closely associated with mitochondrial oxidative...

  3. Effect of one stretch a week applied to the immobilized soleus muscle on rat muscle fiber morphology

    Directory of Open Access Journals (Sweden)

    Gomes A.R.S.

    2004-01-01

    Full Text Available We determined the effect of stretching applied once a week to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Twenty-six male Wistar rats weighing 269 ± 26 g were divided into three groups. Group I, the left soleus was immobilized in the shortened position for 3 weeks; group II, the soleus was immobilized in the shortened position and stretched once a week for 3 weeks; group III, the soleus was submitted only to stretching once a week for 3 weeks. The medial part of the soleus muscle was frozen for histology and muscle fiber area evaluation and the lateral part was used for the determination of number and length of serial sarcomeres. Soleus muscle submitted only to immobilization showed a reduction in weight (44 ± 6%, P = 0.002, in serial sarcomere number (23 ± 15% and in cross-sectional area of the fibers (37 ± 31%, P < 0.001 compared to the contralateral muscles. The muscle that was immobilized and stretched showed less muscle fiber atrophy than the muscles only immobilized (P < 0.05. Surprisingly, in the muscles submitted only to stretching, fiber area was decreased compared to the contralateral muscle (2548 ± 659 vs 2961 ± 806 µm², respectively, P < 0.05. In conclusion, stretching applied once a week for 40 min to the soleus muscle immobilized in the shortened position was not sufficient to prevent the reduction of muscle weight and of serial sarcomere number, but provided significant protection against muscle fiber atrophy. In contrast, stretching normal muscles once a week caused a reduction in muscle fiber area.

  4. Muscle strength rather than muscle mass is associated with osteoporosis in older Chinese adults

    Directory of Open Access Journals (Sweden)

    Yixuan Ma

    2018-02-01

    Conclusion: Based on our study, muscle strength rather than muscle mass is negatively associated with OS in older people; thus, we should pay more attention to muscle strength training in the early stage of the OS.

  5. Electromyography of the buccal musculature of octopus (Octopus bimaculoides): a test of the function of the muscle articulation in support and movement.

    Science.gov (United States)

    Uyeno, Theodore A; Kier, William M

    2007-01-01

    The buccal mass musculature of the octopus (Octopus bimaculoides) was studied with electromyography to test the predictions of a previous morphological study in which we suggested that the muscles of the buccal mass serve as both the effectors of movement and as the joint itself, forming a new category of flexible joint termed a ;muscle articulation'. The predictions of muscle function were tested by correlating muscle electrical activity in isolated buccal masses with spontaneous beak movements. Bipolar electromyography electrodes were implanted in the various beak muscles and beak position was recorded simultaneously with an electronic movement monitor (N=14). The results are consistent with the hypothesis that the lateral mandibular muscles produce opening movements of the beaks and provide the first definitive explanation of the opening mechanism. The results are also consistent with the hypothesis that the superior mandibular muscle functions primarily in closing. Co-contraction of the lateral mandibular muscles and the superior mandibular muscles was also observed, suggesting that these muscles may also stabilize the beaks during movement or provide a means of controlling the location of the pivot between the beaks. This study provides an important first test of the predictions of the role of the complex musculature found in muscle articulations such as the cephalopod buccal mass.

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

    Directory of Open Access Journals (Sweden)

    Kelly Stratton

    2016-07-01

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

  7. Activation of plantar flexor muscles is constrained by multiple muscle synergies rather than joint torques.

    Directory of Open Access Journals (Sweden)

    Takahito Suzuki

    Full Text Available Behavioral evidence has suggested that a small number of muscle synergies may be responsible for activating a variety of muscles. Nevertheless, such dimensionality reduction may also be explained using the perspective of alternative hypotheses, such as predictions based on linear combinations of joint torques multiplied by corresponding coefficients. To compare the explanatory capacity of these hypotheses for describing muscle activation, we enrolled 12 male volunteers who performed isometric plantar flexor contractions at 10-100% of maximum effort. During each plantar flexor contraction, the knee extensor muscles were isometrically contracted at 0%, 50%, or 100% of maximum effort. Electromyographic activity was recorded from the vastus lateralis, medial gastrocnemius (MG, lateral gastrocnemius (LG, and soleus muscles and quantified using the average rectified value (ARV. At lower plantar flexion torque, regression analysis identified a clear linear relationship between the MG and soleus ARVs and between the MG and LG ARVs, suggesting the presence of muscle synergy (r2 > 0.65. The contraction of the knee extensor muscles induced a significant change in the slope of this relationship for both pairs of muscles (MG × soleus, P = 0.002; MG × LG, P = 0.006. Similarly, the slope of the linear relationship between the plantar flexion torque and the ARV of the MG or soleus changed significantly with knee extensor contraction (P = 0.031 and P = 0.041, respectively. These results suggest that muscle synergies characterized by non-mechanical constraints are selectively recruited according to whether contraction of the knee extensor muscles is performed simultaneously, which is relatively consistent with the muscle synergy hypothesis.

  8. Dynamics of tropomyosin in muscle fibers as monitored by saturation transfer EPR of bi-functional probe.

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    Roni F Rayes

    Full Text Available The dynamics of four regions of tropomyosin was assessed using saturation transfer electron paramagnetic resonance in the muscle fiber. In order to fully immobilize the spin probe on the surface of tropomyosin, a bi-functional spin label was attached to i,i+4 positions via cysteine mutagenesis. The dynamics of bi-functionally labeled tropomyosin mutants decreased by three orders of magnitude when reconstituted into "ghost muscle fibers". The rates of motion varied along the length of tropomyosin with the C-terminus position 268/272 being one order of magnitude slower then N-terminal domain or the center of the molecule. Introduction of troponin decreases the dynamics of all four sites in the muscle fiber, but there was no significant effect upon addition of calcium or myosin subfragment-1.

  9. Muscle architecture and fibre characteristics of rat gastrocnemius and semimembranosus muscles during isometric contractions.

    Science.gov (United States)

    Huijing, P A; van Lookeren Campagne, A A; Koper, J F

    1989-01-01

    Rat gastrocnemius medialis (GM) and semimembranosus (SM) muscles have a very different morphology. GM is a very pennate muscle, combining relatively short muscle fibre length with sizable fibre angles and long muscle and aponeurosis lengths. SM is a more parallel-fibred muscle, combining a relatively long fibre length with a small fibre angle and short aponeurosis length. The mechanisms of fibre shortening as well as angle increase are operational in GM as well as SM. However, as a consequence of isometric contraction, changes of fibre length and angle are greater for GM than for SM at any relative muscle length. These differences are particularly notable at short muscle lengths: at 80% of optimum muscle length, fibre length changes of approximately 30% are coupled to fibre angle changes of 15 degrees in GM, while for SM these changes are 4% and 0.6 degrees, respectively. A considerable difference was found for normalized active slack muscle length (GM approximately 80 and SM approximately 45%). This is explained by differences of degree of pennation as well as factors related to differences found for estimated fibre length-force characteristics. Estimated normalized active fibre slack length was considerably smaller for SM than for GM (approximately 40 and 60%, respectively). The most likely explanation of these findings are differences of distribution of optimum fibre lengths, possibly in combination with differences of myofilament lengths and/or fibre length distributions.

  10. Quantitative assessment of muscle in dogs using a vertebral epaxial muscle score.

    Science.gov (United States)

    Freeman, Lisa M; Sutherland-Smith, James; Prantil, Lori R; Sato, Amy F; Rush, John E; Barton, Bruce A

    2017-10-01

    Muscle loss associated with disease (cachexia) or with aging (sarcopenia) is common in dogs, but clinically relevant methods for quantifying muscle loss are needed. We previously validated an ultrasound method of quantifying muscle size in dogs in a single breed. The goal of this study was to assess the variability and reproducibility of the Vertebral Epaxial Muscle Score (VEMS) in other dog breeds. Static ultrasound images were obtained from 38 healthy, neutered dogs of 5 different breeds between 1- and 5-years-old. The maximal transverse right epaxial muscle height and area at the level of the 13th thoracic vertebra (T13) were measured. Length of the 4th thoracic vertebra (T4) was measured from thoracic radiography. Ratios of the muscle height and area to vertebral length (height/T4 and area/T4, respectively) were calculated to account for differences in body size among breeds. Reproducibility testing was performed on 2 dogs of each breed (26% of the total) to determine intra- and inter-investigator reproducibility, as well as intra-class correlation. Mean height/T4 = 1.02 ± 0.18 and mean area/T4 = 3.32 ± 1.68. There was no significant difference for height/T4 ( P = 0.10) among breeds, but breeds were significantly different in area/T4 ( P dogs of different sizes and body conformations. Studies assessing this technique in dogs with congestive heart failure and other diseases associated with muscle loss are warranted.

  11. Effect of transcutaneous electrical muscle stimulation on muscle volume in patients with septic shock

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum; Møller, Kirsten; Jensen, Claus V

    2011-01-01

    Objective: Intensive care unit admission is associated with muscle wasting and impaired physical function. We investigated the effect of early transcutaneous electrical muscle stimulation on quadriceps muscle volume in patients with septic shock. Design: Randomized interventional study using...

  12. Ethanol Exposure Causes Muscle Degeneration in Zebrafish

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    Elizabeth C. Coffey

    2018-03-01

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

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

    DEFF Research Database (Denmark)

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

    2000-01-01

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

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

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    Lynn Bar-On

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

  15. Healthy Muscles Matter

    Science.gov (United States)

    ... or lying down, and faster when you’re running or playing sports and your skeletal muscles need more blood to help them do their work. What can go wrong? Injuries Almost everyone has had sore muscles after exercising ...

  16. Neuromuscular organization of avian flight muscle: architecture of single muscle fibres in muscle units of the pectoralis (pars thoracicus) of pigeon (Columba livia)

    Science.gov (United States)

    Sokoloff, A. J.

    1999-01-01

    The M. pectoralis (pars thoracicus) of pigeons (Columba livia) is comprised of short muscle fibres that do not extend from muscle origin to insertion but overlap 'in-series'. Individual pectoralis motor units are limited in territory to a portion of muscle length and are comprised of either fast twitch, oxidative and glycolytic fibres (FOG) or fast twitch and glycolytic fibres (FG). FOG fibres make up 88 to 90% of the total muscle population and have a mean diameter one-half of that of the relatively large FG fibres. Here we report on the organization of individual fibres identified in six muscle units depleted of glycogen, three comprised of FOG fibres and three comprised of FG fibres. For each motor unit, fibre counts revealed unequal numbers of depleted fibres in different unit cross-sections. We traced individual fibres in one unit comprised of FOG fibres and a second comprised of FG fibres. Six fibres from a FOG unit (total length 15.45 mm) ranged from 10.11 to 11.82 mm in length and averaged (± s.d.) 10.74 ± 0.79 mm. All originated bluntly (en mass) from a fascicle near the proximal end of the muscle unit and all terminated intramuscularly. Five of these ended in a taper and one ended bluntly. Fibres coursed on average for 70% of the muscle unit length. Six fibres from a FG unit (total length 34.76 mm) ranged from 8.97 to 18.38 mm in length and averaged 15.32 ± 3.75 mm. All originated bluntly and terminated intramuscularly; one of these ended in a taper and five ended bluntly. Fibres coursed on average for 44% of the muscle unit length. Because fibres of individual muscle units do not extend the whole muscle unit territory, the effective cross-sectional area changes along the motor unit length. These non-uniformities in the distribution of fibres within a muscle unit emphasize that the functional interactions within and between motor units are complex.

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

    Science.gov (United States)

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

    2012-07-01

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

  18. A decline in PABPN1 induces progressive muscle weakness in oculopharyngeal muscle dystrophy and in muscle aging

    DEFF Research Database (Denmark)

    Anvar, Seyed Yahya; Raz, Yotam; Verway, Nisha

    2013-01-01

    Oculopharyngeal muscular dystrophy (OPMD) is caused by trinucleotide repeat expansion mutations in Poly(A) binding protein 1 (PABPN1). PABPN1 is a regulator of mRNA stability and is ubiquitously expressed. Here we investigated how symptoms in OPMD initiate only at midlife and why a subset...... of skeletal muscles is predominantly affected. Genome-wide RNA expression profiles from Vastus lateralis muscles human carriers of expanded-PABPN1 at pre-symptomatic and symptomatic stages were compared with healthy controls. Major expression changes were found to be associated with age rather than...... with expression of expanded-PABPN1, instead transcriptomes of OPMD and elderly muscles were significantly similar (P...

  19. Skeletal muscle regeneration is modulated by inflammation

    Directory of Open Access Journals (Sweden)

    Wenjun Yang

    2018-04-01

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

  20. Myostatin genotype regulates muscle-specific miRNA expression in mouse pectoralis muscle

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    Cheng Ye

    2010-11-01

    Full Text Available Abstract Background Loss of functional Myostatin results in a dramatic increase in skeletal muscle mass. It is unknown what role miRNAs play in Myostatin mediated repression of skeletal muscle mass. We hypothesized that Myostatin genotype would be associated with the differential expression of miRNAs in skeletal muscle. Findings Loss of functional Myostatin resulted in a significant increase (p .2 on miR-24 expression level. Myostatin genotype did not affect the expression level of MyoD or Myogenin (P > 0.5. Conclusions Myostatin may regulates the expression of miRNAs such as miR-133a, miR-133b, miR-1, and miR-206 in skeletal muscle as it has been observed that the expression of those miRNAs are significantly higher in myostatin null mice compared to wild type and heterozygous mice. In contrast, expression of myogenic factors such as MyoD or Myogenin has not been affected by myostatin in the muscle tissue.

  1. Effects of muscle activation on shear between human soleus and gastrocnemius muscles.

    Science.gov (United States)

    Finni, T; Cronin, N J; Mayfield, D; Lichtwark, G A; Cresswell, A G

    2017-01-01

    Lateral connections between muscles provide pathways for myofascial force transmission. To elucidate whether these pathways have functional roles in vivo, we examined whether activation could alter the shear between the soleus (SOL) and lateral gastrocnemius (LG) muscles. We hypothesized that selective activation of LG would decrease the stretch-induced shear between LG and SOL. Eleven volunteers underwent a series of knee joint manipulations where plantar flexion force, LG, and SOL muscle fascicle lengths and relative displacement of aponeuroses between the muscles were obtained. Data during a passive full range of motion were recorded, followed by 20° knee extension stretches in both passive conditions and with selective electrical stimulation of LG. During active stretch, plantar flexion force was 22% greater (P stronger (stiffer) connectivity between the two muscles, at least at flexed knee joint angles, which may serve to facilitate myofascial force transmission. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Multifidus Muscle Changes After Back Injury Are Characterized by Structural Remodeling of Muscle, Adipose and Connective Tissue, but Not Muscle Atrophy: Molecular and Morphological Evidence.

    Science.gov (United States)

    Hodges, Paul W; James, Gregory; Blomster, Linda; Hall, Leanne; Schmid, Annina; Shu, Cindy; Little, Chris; Melrose, James

    2015-07-15

    Longitudinal case-controlled animal study. To investigate putative cellular mechanisms to explain structural changes in muscle and adipose and connective tissues of the back muscles after intervertebral disc (IVD) injury. Structural back muscle changes are ubiquitous with back pain/injury and considered relevant for outcome, but their exact nature, time course, and cellular mechanisms remain elusive. We used an animal model that produces phenotypic back muscle changes after IVD injury to study these issues at the cellular/molecular level. Multifidus muscle was harvested from both sides of the spine at L1-L2 and L3-L4 IVDs in 27 castrated male sheep at 3 (n = 10) or 6 (n = 17) months after a surgical anterolateral IVD injury at both levels. Ten control sheep underwent no surgery (3 mo, n = 4; 6 mo, n = 6). Tissue was harvested at L4 for histological analysis of cross-sectional area of muscle and adipose and connective tissue (whole muscle), plus immunohistochemistry to identify proportion and cross-sectional area of individual muscle fiber types in the deepest fascicle. Quantitative polymerase chain reaction measured gene expression of typical cytokines/signaling molecules at L2. Contrary to predictions, there was no multifidus muscle atrophy (whole muscle or individual fiber). There was increased adipose and connective tissue (fibrotic proliferation) cross-sectional area and slow-to-fast muscle fiber transition at 6 but not 3 months. Within the multifidus muscle, increases in the expression of several cytokines (tumor necrosis factor α and interleukin-1β) and molecules that signal trophic/atrophic processes for the 3 tissue types (e.g., growth factor pathway [IGF-1, PI3k, Akt1, mTOR], potent tissue modifiers [calcineurin, PCG-1α, and myostatin]) were present. This study provides cellular evidence that refutes the presence of multifidus muscle atrophy accompanying IVD degeneration at this intermediate time point. Instead, adipose/connective tissue increased in

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

    Directory of Open Access Journals (Sweden)

    Krzysztof Buśko

    2012-01-01

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

  4. 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

  5. Impaired muscle glycogen resynthesis after a marathon is not caused by decreased muscle GLUT-4 content

    DEFF Research Database (Denmark)

    Asp, S; Rohde, T; Richter, Erik

    1997-01-01

    Our purpose was to investigate whether the slow rate of muscle glycogen resynthesis after a competitive marathon is associated with a decrease in the total muscle content of the muscle glucose transporter (GLUT-4). Seven well-trained marathon runners participated in the study, and muscle biopsies...... were obtained from the lateral head of the gastrocnemius muscle before, immediately after, and 1, 2, and 7 days after the marathon, as were venous blood samples. Muscle GLUT-4 content was unaltered over the experimental period. Muscle glycogen concentration was 758 +/- 53 mmol/kg dry weight before...... the marathon and decreased to 148 +/- 39 mmol/kg dry weight immediately afterward. Despite a carbohydrate-rich diet (containing at least 7 g carbohydrate.kg body mass-1.day-1), the muscle glycogen concentration remained 30% lower than before-race values 2 days after the race, whereas it had returned to before...

  6. Muscle insulin sensitivity and glucose metabolism are controlled by the intrinsic muscle clock★

    Science.gov (United States)

    Dyar, Kenneth A.; Ciciliot, Stefano; Wright, Lauren E.; Biensø, Rasmus S.; Tagliazucchi, Guidantonio M.; Patel, Vishal R.; Forcato, Mattia; Paz, Marcia I.P.; Gudiksen, Anders; Solagna, Francesca; Albiero, Mattia; Moretti, Irene; Eckel-Mahan, Kristin L.; Baldi, Pierre; Sassone-Corsi, Paolo; Rizzuto, Rosario; Bicciato, Silvio; Pilegaard, Henriette; Blaauw, Bert; Schiaffino, Stefano

    2013-01-01

    Circadian rhythms control metabolism and energy homeostasis, but the role of the skeletal muscle clock has never been explored. We generated conditional and inducible mouse lines with muscle-specific ablation of the core clock gene Bmal1. Skeletal muscles from these mice showed impaired insulin-stimulated glucose uptake with reduced protein levels of GLUT4, the insulin-dependent glucose transporter, and TBC1D1, a Rab-GTPase involved in GLUT4 translocation. Pyruvate dehydrogenase (PDH) activity was also reduced due to altered expression of circadian genes Pdk4 and Pdp1, coding for PDH kinase and phosphatase, respectively. PDH inhibition leads to reduced glucose oxidation and diversion of glycolytic intermediates to alternative metabolic pathways, as revealed by metabolome analysis. The impaired glucose metabolism induced by muscle-specific Bmal1 knockout suggests that a major physiological role of the muscle clock is to prepare for the transition from the rest/fasting phase to the active/feeding phase, when glucose becomes the predominant fuel for skeletal muscle. PMID:24567902

  7. Skeletal Muscle Regeneration, Repair and Remodelling in Aging: The Importance of Muscle Stem Cells and Vascularization.

    Science.gov (United States)

    Joanisse, Sophie; Nederveen, Joshua P; Snijders, Tim; McKay, Bryon R; Parise, Gianni

    2017-01-01

    Sarcopenia is the age-related loss of skeletal muscle mass and strength. Ultimately, sarcopenia results in the loss of independence, which imposes a large financial burden on healthcare systems worldwide. A critical facet of sarcopenia is the diminished ability for aged muscle to regenerate, repair and remodel. Over the years, research has focused on elucidating underlying mechanisms of sarcopenia and the impaired ability of muscle to respond to stimuli with aging. Muscle-specific stem cells, termed satellite cells (SC), play an important role in maintaining muscle health throughout the lifespan. It is well established that SC are essential in skeletal muscle regeneration, and it has been hypothesized that a reduction and/or dysregulation of the SC pool, may contribute to accelerated loss of skeletal muscle mass that is observed with advancing age. The preservation of skeletal muscle tissue and its ability to respond to stimuli may be impacted by reduced SC content and impaired function observed with aging. Aging is also associated with a reduction in capillarization of skeletal muscle. We have recently demonstrated that the distance between type II fibre-associated SC and capillaries is greater in older compared to younger adults. The greater distance between SC and capillaries in older adults may contribute to the dysregulation in SC activation ultimately impairing muscle's ability to remodel and, in extreme circumstances, regenerate. This viewpoint will highlight the importance of optimal SC activation in addition to skeletal muscle capillarization to maximize the regenerative potential of skeletal muscle in older adults. © 2016 S. Karger AG, Basel.

  8. 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

    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...... between muscle fiber diameter, muscle fiber type distribution, or capillary density and degree of neuropathy or muscle strength for either patient group. Muscle fiber diameter and the proportion of Type II fibers were greater for T1D patients than both T2D patients and controls. The T2D patients had fewer...

  9. Korean mistletoe (Viscum album coloratum) extract regulates gene expression related to muscle atrophy and muscle hypertrophy.

    Science.gov (United States)

    Jeong, Juseong; Park, Choon-Ho; Kim, Inbo; Kim, Young-Ho; Yoon, Jae-Min; Kim, Kwang-Soo; Kim, Jong-Bae

    2017-01-21

    Korean mistletoe (Viscum album coloratum) is a semi-parasitic plant that grows on various trees and has a diverse range of effects on biological functions, being implicated in having anti-tumor, immunostimulatory, anti-diabetic, and anti-obesity properties. Recently, we also reported that Korean mistletoe extract (KME) improves endurance exercise in mice, suggesting its beneficial roles in enhancing the capacity of skeletal muscle. We examined the expression pattern of several genes concerned with muscle physiology in C2C12 myotubes cells to identify whether KME inhibits muscle atrophy or promotes muscle hypertrophy. We also investigated these effects of KME in denervated mice model. Interestingly, KME induced the mRNA expression of SREBP-1c, PGC-1α, and GLUT4, known positive regulators of muscle hypertrophy, in C2C12 cells. On the contrary, KME reduced the expression of Atrogin-1, which is directly involved in the induction of muscle atrophy. In animal models, KME mitigated the decrease of muscle weight in denervated mice. The expression of Atrogin-1 was also diminished in those mice. Moreover, KME enhanced the grip strength and muscle weight in long-term feeding mice. Our results suggest that KME has beneficial effects on muscle atrophy and muscle hypertrophy.

  10. Skeletal Muscle Fibre-Specific Knockout of p53 Does Not Reduce Mitochondrial Content or Enzyme Activity

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    Ben Stocks

    2017-12-01

    Full Text Available Tumour protein 53 (p53 has been implicated in the regulation of mitochondrial biogenesis in skeletal muscle, with whole-body p53 knockout mice displaying impairments in basal mitochondrial content, respiratory capacity, and enzyme activity. This study aimed to determine the effect of skeletal muscle-specific loss of p53 on mitochondrial content and enzyme activity. Mitochondrial protein content, enzyme activity and mRNA profiles were assessed in skeletal muscle of 8-week-old male muscle fibre-specific p53 knockout mice (p53 mKO and floxed littermate controls (WT under basal conditions. p53 mKO and WT mice displayed similar content of electron transport chain proteins I-V and citrate synthase enzyme activity in skeletal muscle. In addition, the content of proteins regulating mitochondrial morphology (MFN2, mitofillin, OPA1, DRP1, FIS1, fatty acid metabolism (β-HAD, ACADM, ACADL, ACADVL, carbohydrate metabolism (HKII, PDH, energy sensing (AMPKα2, AMPKβ2, and gene transcription (NRF1, PGC-1α, and TFAM were comparable in p53 mKO and WT mice (p > 0.05. Furthermore, p53 mKO mice exhibited normal mRNA profiles of targeted mitochondrial, metabolic and transcriptional proteins (p > 0.05. Thus, it appears that p53 expression in skeletal muscle fibres is not required to develop or maintain mitochondrial protein content or enzyme function in skeletal muscle under basal conditions.

  11. Muscle as an endocrine organ: focus on muscle-derived interleukin-6

    DEFF Research Database (Denmark)

    Febbraio, M.A.; Pedersen, Bente Klarlund

    2008-01-01

    Skeletal muscle has recently been identified as an endocrine organ. It has, therefore, been suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers and exert paracrine, autocrine, or endocrine effects should be classified as "myokines." Recent...... period when insulin action is enhanced but, on the other hand, IL-6 has been associated with obesity and reduced insulin action. This review focuses on the myokine IL-6, its regulation by exercise, its signaling pathways in skeletal muscle, and its role in metabolism in both health and disease...

  12. Partial transformation from fast to slow muscle fibers induced by deafferentation of capsaicin-sensitive muscle afferents.

    Science.gov (United States)

    Brunetti, O; Barazzoni, A M; Della Torre, G; Clavenzani, P; Pettorossi, V E; Bortolami, R

    1997-11-01

    Mechanical and histochemical characteristics of the lateral gastrocnemius (LG) muscle of the rat were examined 21 days after capsaicin injection into the LG muscle. The capsaicin caused a decrease in generation rate of twitch and tetanic tension and an increase in fatigue resistance of LG muscle. The histochemical muscle fiber profile evaluated by myosin adenosine triphosphatase and reduced nicotinamide adenine dinucleotide tetrazolium reductase methods showed an increase of type I and IIC fibers and a decrease of the type IIB in whole muscle, and a decrease of the IIA, IIX fibers in the red part accompanied by their increase in the white part. Therefore the capsaicin treatment, which selectively eliminated fibers belonging to the III and IV groups of muscle afferents, induced muscle fiber transformation from fast contracting fatiguing fibers to slowly contracting nonfatiguing ones.

  13. PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells.

    Science.gov (United States)

    Ho, Tsung-Chuan; Chiang, Yi-Pin; Chuang, Chih-Kuang; Chen, Show-Li; Hsieh, Jui-Wen; Lan, Yu-Wen; Tsao, Yeou-Ping

    2015-08-01

    In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser(93)-Leu(112)) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2'-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration. Copyright © 2015 the American Physiological Society.

  14. Redox Control of Skeletal Muscle Regeneration.

    Science.gov (United States)

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

    2017-08-10

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

  15. Skeletal muscle phosphatidylcholine and phosphatidylethanolamine respond to exercise and influence insulin sensitivity in men.

    Science.gov (United States)

    Lee, Sindre; Norheim, Frode; Gulseth, Hanne L; Langleite, Torgrim M; Aker, Andreas; Gundersen, Thomas E; Holen, Torgeir; Birkeland, Kåre I; Drevon, Christian A

    2018-04-25

    Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) composition in skeletal muscle have been linked to insulin sensitivity. We evaluated the relationships between skeletal muscle PC:PE, physical exercise and insulin sensitivity. We performed lipidomics and measured PC and PE in m. vastus lateralis biopsies obtained from 13 normoglycemic normal weight men and 13 dysglycemic overweight men at rest, immediately after 45 min of cycling at 70% maximum oxygen uptake, and 2 h post-exercise, before as well as after 12 weeks of combined endurance- and strength-exercise intervention. Insulin sensitivity was monitored by euglycemic-hyperinsulinemic clamp. RNA-sequencing was performed on biopsies, and mitochondria and lipid droplets were quantified on electron microscopic images. Exercise intervention for 12 w enhanced insulin sensitivity by 33%, skeletal muscle levels of PC by 21%, PE by 42%, and reduced PC:PE by 16%. One bicycle session reduced PC:PE by 5%. PC:PE correlated negatively with insulin sensitivity (β = -1.6, P insulin sensitivity.

  16. 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

    The etiology of mammalian senescence is suggested to involve the progressive impairment of mitochondrial function; however, direct observations of age-induced alterations in actual respiratory chain function are lacking. Accordingly, we assessed mitochondrial function via high-resolution respirom......The etiology of mammalian senescence is suggested to involve the progressive impairment of mitochondrial function; however, direct observations of age-induced alterations in actual respiratory chain function are lacking. Accordingly, we assessed mitochondrial function via high......-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...

  17. The characteristics of a pneumatic muscle

    Directory of Open Access Journals (Sweden)

    Pietrala Dawid

    2017-01-01

    Full Text Available The article presents static and dynamic characteristics of pneumatic muscles. It presents the structure of the laboratory stand used to test pneumatic muscles. It discusses the methodology for determination of static and dynamic characteristics. The paper also illustrates characteristics showing the relationship of pneumatic muscles length and operating pressure, at a constant loading force (isotonic characteristics. It presents characteristics showing the relationship of pneumatic muscles shortening and values of loading forces, at a constant operational pressure (isobaric characteristics. It also shows the dependence of force generated by the muscle on the operating pressure, at a constant value of pneumatic muscles shortening (isometric characteristics. The paper also presents dynamic characteristics of a pneumatic muscle showing the response of an object to a gradual change in the operating pressure, at a constant loading force acting on the pneumatic muscle.

  18. The characteristics of a pneumatic muscle

    Science.gov (United States)

    Pietrala, Dawid

    The article presents static and dynamic characteristics of pneumatic muscles. It presents the structure of the laboratory stand used to test pneumatic muscles. It discusses the methodology for determination of static and dynamic characteristics. The paper also illustrates characteristics showing the relationship of pneumatic muscles length and operating pressure, at a constant loading force (isotonic characteristics). It presents characteristics showing the relationship of pneumatic muscles shortening and values of loading forces, at a constant operational pressure (isobaric characteristics). It also shows the dependence of force generated by the muscle on the operating pressure, at a constant value of pneumatic muscles shortening (isometric characteristics). The paper also presents dynamic characteristics of a pneumatic muscle showing the response of an object to a gradual change in the operating pressure, at a constant loading force acting on the pneumatic muscle.

  19. Muscles and their myokines.

    Science.gov (United States)

    Pedersen, Bente Klarlund

    2011-01-15

    In the past, the role of physical activity as a life-style modulating factor has been considered as that of a tool to balance energy intake. Although it is important to avoid obesity, physical inactivity should be discussed in a much broader context. There is accumulating epidemiological evidence that a physically active life plays an independent role in the protection against type 2 diabetes, cardiovascular diseases, cancer, dementia and even depression. For most of the last century, researchers sought a link between muscle contraction and humoral changes in the form of an 'exercise factor', which could be released from skeletal muscle during contraction and mediate some of the exercise-induced metabolic changes in other organs such as the liver and the adipose tissue. We have suggested that cytokines or other peptides that are produced, expressed and released by muscle fibres and exert autocrine, paracrine or endocrine effects should be classified as 'myokines'. Given that skeletal muscle is the largest organ in the human body, our discovery that contracting skeletal muscle secretes proteins sets a novel paradigm: skeletal muscle is an endocrine organ producing and releasing myokines, which work in a hormone-like fashion, exerting specific endocrine effects on other organs. Other myokines work via paracrine mechanisms, exerting local effects on signalling pathways involved in muscle metabolism. It has been suggested that myokines may contribute to exercise-induced protection against several chronic diseases.

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

    Directory of Open Access Journals (Sweden)

    M. Prasad Naik

    2015-10-01

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-24

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

  3. Assessment of muscle fatigue using electromygraphm sensing

    Science.gov (United States)

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

    2017-08-01

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

  4. Nuclear Positioning in Muscle Development and Disease

    OpenAIRE

    Eric eFolker; Mary eBaylies

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Grégory Lacraz

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

  6. Bilateral Tensor Fasciae Suralis Muscles in a Cadaver with Unilateral Accessory Flexor Digitorum Longus Muscle

    Directory of Open Access Journals (Sweden)

    Logan S. W. Bale

    2017-01-01

    Full Text Available Muscle variants are routinely encountered in the dissection laboratory and in clinical practice and therefore anatomists and clinicians need to be aware of their existence. Here we describe two different accessory muscles identified while performing educational dissection of a 51-year-old male cadaver. Tensor fasciae suralis, a rare muscle variant, was identified bilaterally and accessory flexor digitorum longus, a more common muscle variant, was present unilaterally. Tensor fasciae suralis and accessory flexor digitorum longus are clinically relevant muscle variants. To our knowledge, the coexistence of tensor fasciae suralis and accessory flexor digitorum longus in the same individual has not been reported in either cadaveric or imaging studies.

  7. Ultrasound of skeletal muscle injury.

    Science.gov (United States)

    Koh, Eamon Su Chun; McNally, Eugene G

    2007-06-01

    The professional and recreational demands of modern society make the treatment of muscle injury an increasingly important clinical problem, particularly in the athletic population. In the elite athlete, significant financial and professional pressures may also exist that emphasize the need for accurate diagnosis and treatment. With new advances in ultrasound technology, images of exquisite detail allow diagnosis of muscle injury that matches the accuracy of magnetic resonance imaging (MRI). Furthermore, the benefits of real-time and Doppler imaging, ability to perform interventional procedures, and relative cost benefits compared with MRI place ultrasound at the forefront for investigation for these injuries in many circumstances. Muscle injury may be divided into acute and chronic pathology, with muscle strain injury the most common clinical problem presenting to sports physicians. This article reviews the spectrum of acute and chronic muscle injuries, with particular attention to clinical features and some common or important muscle strain injuries.

  8. Dynamic cardiomyoplasty using artificial muscle.

    Science.gov (United States)

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

    2008-01-01

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

  9. The role of Six1 in muscle progenitor cells and the establishment of fast-twitch muscle fibres

    OpenAIRE

    Nord, Hanna

    2014-01-01

    Myogenesis is the process of skeletal muscle tissue formation where committed muscle progenitor cells differentiate into skeletal muscle fibres. Depending on the instructive cues the muscle progenitor cells receive they will differentiate into specific fibre types with different properties. The skeletal muscle fibres can be broadly classified as fast-twitch fibres or slow-twitch fibres, based on their contractile speed. However, subgroups of fast- and slow-twitch fibres with different metabol...

  10. Magnetic resonance imaging of facial muscles

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-11-15

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

  11. Magnetic resonance imaging of facial muscles

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  12. Physical exercise in aging human skeletal muscle increases mitochondrial calcium uniporter expression levels and affects mitochondria dynamics.

    Science.gov (United States)

    Zampieri, Sandra; Mammucari, Cristina; Romanello, Vanina; Barberi, Laura; Pietrangelo, Laura; Fusella, Aurora; Mosole, Simone; Gherardi, Gaia; Höfer, Christian; Löfler, Stefan; Sarabon, Nejc; Cvecka, Jan; Krenn, Matthias; Carraro, Ugo; Kern, Helmut; Protasi, Feliciano; Musarò, Antonio; Sandri, Marco; Rizzuto, Rosario

    2016-12-01

    Age-related sarcopenia is characterized by a progressive loss of muscle mass with decline in specific force, having dramatic consequences on mobility and quality of life in seniors. The etiology of sarcopenia is multifactorial and underlying mechanisms are currently not fully elucidated. Physical exercise is known to have beneficial effects on muscle trophism and force production. Alterations of mitochondrial Ca 2+ homeostasis regulated by mitochondrial calcium uniporter (MCU) have been recently shown to affect muscle trophism in vivo in mice. To understand the relevance of MCU-dependent mitochondrial Ca 2+ uptake in aging and to investigate the effect of physical exercise on MCU expression and mitochondria dynamics, we analyzed skeletal muscle biopsies from 70-year-old subjects 9 weeks trained with either neuromuscular electrical stimulation (ES) or leg press. Here, we demonstrate that improved muscle function and structure induced by both trainings are linked to increased protein levels of MCU Ultrastructural analyses by electron microscopy showed remodeling of mitochondrial apparatus in ES-trained muscles that is consistent with an adaptation to physical exercise, a response likely mediated by an increased expression of mitochondrial fusion protein OPA1. Altogether these results indicate that the ES-dependent physiological effects on skeletal muscle size and force are associated with changes in mitochondrial-related proteins involved in Ca 2+ homeostasis and mitochondrial shape. These original findings in aging human skeletal muscle confirm the data obtained in mice and propose MCU and mitochondria-related proteins as potential pharmacological targets to counteract age-related muscle loss. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  13. Architectural differences between the hamstring muscles.

    Science.gov (United States)

    Kellis, Eleftherios; Galanis, Nikiforos; Kapetanos, George; Natsis, Konstantinos

    2012-08-01

    The purpose of this study was to understand the detailed architectural properties of the human hamstring muscles. The long (BFlh) and short (BFsh) head of biceps femoris, semimembranosus (SM) and semitendinosus (ST) muscles were dissected and removed from their origins in eight cadaveric specimens (age 67.8±4.3 years). Mean fiber length, sarcomere length, physiological cross-section area and pennation angle were measured. These data were then used to calculate a similarity index (δ) between pairs of muscles. The results indicated moderate similarity between BFlh and BFsh (δ=0.54) and between BFlh and SM (δ=0.35). In contrast, similarity was low between SM and ST (δ=0.98) and between BFlh and SM (δ=1.17). The fascicle length/muscle length ratio was higher for the ST (0.58) and BFsh (0.50) compared with the BFlh (0.27) and SM (0.22). There were, however, high inter-correlations between individual muscle architecture values, especially for muscle thickness and fascicle length data sets. Prediction of the whole hamstring architecture was achieved by combining data from all four muscles. These data show different designs of the hamstring muscles, especially between the SM and ST (medial) and BFlh and BFsh (lateral) muscles. Modeling the hamstrings as one muscle group by assuming uniform inter-muscular architecture yields less accurate representation of human hamstring muscle function. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Statin Use and Self-Reported Hindering Muscle Complaints in Older Persons: A Population Based Study.

    Directory of Open Access Journals (Sweden)

    Milly A van der Ploeg

    Full Text Available Statins are widely used by older persons in primary and secondary prevention of cardiovascular disease. Although serious adverse events are rare, many statin users report mild muscle pain and/or muscle weakness. It's unclear what impact statins exert on a patient's daily life. Research on statin related side effects in older persons is relatively scarce. We therefore investigated the relation between statin use and self-reported hindering muscle complaints in older persons in the general population.The present research was performed within the Integrated Systematic Care for Older Persons (ISCOPE study in the Netherlands (Netherlands trial register, NTR1946. All registered adults aged ≥ 75 years from 59 participating practices (n = 12,066 were targeted. Information about the medical history and statin use at baseline and after 9 months was available for 4355 participants from the Electronic Patient Records of the general practitioners. In the screening questionnaire at baseline we asked participants: 'At the moment, which health complaints limit you the most in your day-to-day life?' Answers indicating muscle or musculoskeletal complaints were coded as such. No specific questions about muscle complaints were asked.The participants had a median age of 80.3 (IQR 77.6-84.4 years, 60.8% were female and 28.5% had a history of CVD. At baseline 29% used a statin. At follow-up, no difference was found in the prevalence of self-reported hindering muscle complaints in statin users compared to non-statin users (3.3% vs. 2.5%, OR 1.39, 95% CI 0.94-2.05; P = 0.98. Discontinuation of statin use during follow-up was independent of self-reported hindering muscle complaints.Based on the present findings, prevalent statin use in this community-dwelling older population is not associated with self-reported hindering muscle complaints; however, the results might be different for incident users.

  15. Statin Use and Self-Reported Hindering Muscle Complaints in Older Persons: A Population Based Study.

    Science.gov (United States)

    van der Ploeg, Milly A; Poortvliet, Rosalinde K E; van Blijswijk, Sophie C E; den Elzen, Wendy P J; van Peet, Petra G; de Ruijter, Wouter; Blom, Jeanet W; Gussekloo, Jacobijn

    2016-01-01

    Statins are widely used by older persons in primary and secondary prevention of cardiovascular disease. Although serious adverse events are rare, many statin users report mild muscle pain and/or muscle weakness. It's unclear what impact statins exert on a patient's daily life. Research on statin related side effects in older persons is relatively scarce. We therefore investigated the relation between statin use and self-reported hindering muscle complaints in older persons in the general population. The present research was performed within the Integrated Systematic Care for Older Persons (ISCOPE) study in the Netherlands (Netherlands trial register, NTR1946). All registered adults aged ≥ 75 years from 59 participating practices (n = 12,066) were targeted. Information about the medical history and statin use at baseline and after 9 months was available for 4355 participants from the Electronic Patient Records of the general practitioners. In the screening questionnaire at baseline we asked participants: 'At the moment, which health complaints limit you the most in your day-to-day life?' Answers indicating muscle or musculoskeletal complaints were coded as such. No specific questions about muscle complaints were asked. The participants had a median age of 80.3 (IQR 77.6-84.4) years, 60.8% were female and 28.5% had a history of CVD. At baseline 29% used a statin. At follow-up, no difference was found in the prevalence of self-reported hindering muscle complaints in statin users compared to non-statin users (3.3% vs. 2.5%, OR 1.39, 95% CI 0.94-2.05; P = 0.98). Discontinuation of statin use during follow-up was independent of self-reported hindering muscle complaints. Based on the present findings, prevalent statin use in this community-dwelling older population is not associated with self-reported hindering muscle complaints; however, the results might be different for incident users.

  16. PLASTICITY OF SKELETAL MUSCLE STUDIED BY STEREOLOGY

    Directory of Open Access Journals (Sweden)

    Ida Eržen

    2011-05-01

    Full Text Available The present contribution provides an overview of stereological methods applied in the skeletal muscle research at the Institute of Anatomy of the Medical Faculty in Ljubljana. Interested in skeletal muscle plasticity we studied three different topics: (i expression of myosin heavy chain isoforms in slow and fast muscles under experimental conditions, (ii frequency of satellite cells in young and old human and rat muscles and (iii capillary supply of rat fast and slow muscles. We analysed the expression of myosin heavy chain isoforms within slow rat soleus and fast extensor digitorum longus muscles after (i homotopic and heterotopic transplantation of both muscles, (ii low frequency electrical stimulation of the fast muscle and (iii transposition of the fast nerve to the slow muscle. The models applied were able to turn the fast muscle into a completely slow muscle, but not vice versa. One of the indicators for the regenerative potential of skeletal muscles is its satellite cell pool. The estimated parameters, number of satellite cells per unit fibre length, corrected to the reference sarcomere length (Nsc/Lfib and number of satellite cells per number of nuclei (myonuclei and satellite cell nuclei (Nsc/Nnucl indicated that the frequency of M-cadherin stained satellite cells declines in healthy old human and rat muscles compared to young muscles. To access differences in capillary densities among slow and fast muscles and slow and fast muscle fibres, we have introduced Slicer and Fakir methods, and tested them on predominantly slow and fast rat muscles. Discussing three different topics that require different approach, the present paper reflects the three decades of the development of stereological methods: 2D analysis by simple point counting in the 70's, the disector in the 80's and virtual spatial probes in the 90's. In all methods the interactive computer assisted approach was utilised.

  17. Psoas muscle cross-sectional area as a measure of whole body lean muscle mass in maintenance hemodialysis patients

    Science.gov (United States)

    Morrell, Glen R.; Ikizler, Talat A.; Chen, Xiaorui; Heilbrun, Marta E.; Wei, Guo; Boucher, Robert; Beddhu, Srinivasan

    2016-01-01

    Objective We investigate whether psoas or paraspinous muscle area measured on a single L4–5 image is a useful measure of whole lean body mass compared to dedicated mid-thigh magnetic resonance imaging (MRI). Design Observational study. Setting Outpatient dialysis units and a research clinic. Subjects 105 adult participants on maintenance hemodialysis. No control group was used. Exposure variables Psoas muscle area, paraspinous muscle area, and mid-thigh muscle area (MTMA) were measured by MRI. Main outcome measure Lean body mass was measured by dual-energy absorptiometry (DEXA) scan. Results In separate multivariable linear regression models, psoas, paraspinous, and mid-thigh muscle area were associated with increase in lean body mass. In separate multivariate logistic regression models, c-statistics for diagnosis of sarcopenia (defined as lean body mass) were 0.69 for paraspinous muscle area, 0.81 for psoas muscle area, and 0.89 for mid-thigh muscle area. With sarcopenia defined as lean body mass, the corresponding c-statistics were 0.71, 0.92, and 0.94. Conclusions We conclude that psoas muscle area provides a good measure of whole body muscle mass, better than paraspinous muscle area but slightly inferior to mid thigh measurement. Hence, in body composition studies a single axial MR image at the L4–L5 level can be used to provide information on both fat and muscle and may eliminate the need for time-consuming measurement of muscle area in the thigh. PMID:26994780

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

    Science.gov (United States)

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

    2017-02-02

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

  19. the sternalis muscle

    African Journals Online (AJOL)

    2009-08-17

    Aug 17, 2009 ... CASE REPORT. CASE. 72. SA JOURNAL OF RADIOLOGY • August 2009. CASE R. Introduction ... tion is being given to imaging the medial breast, and the sternalis muscle will be revealed with increasing ... The origin of this muscle is uncertain, with pectoralis major, rectus abdominus and sternomastoid ...

  20. Muscle performance after the menopause.

    Science.gov (United States)

    Sirola, Joonas; Rikkonen, Toni

    2005-06-01

    The timing of the menopause transition has remained fairly constant throughout history. It represents a milestone in female health and, after passing through it, women experience increased musculoskeletal and cardiovascular morbidity. Muscle performance is an important determinant of functional capacity and quality of life among the elderly and is also involved in the maintenance of balance. Therefore, good muscle strength can prevent fragility fractures and lessen the burden of osteoporosis. Muscle strength begins to decline during the perimenopausal years and this phenomenon seems to be partly estrogen dependent. Randomized controlled trials have indicated that hormone replacement therapy may prevent a decline in muscle performance, although the exact mechanism of estrogen-dependent sarcopenia remains to be clarified. Exercises have been shown to improve postmenopausal muscle performance and hormone replacement therapy may also potentiate these beneficial effects. Improvement or maintenance of muscle strength alone, however, may not be considered as a primary indication for long-term hormone replacement therapy in view of current knowledge of its risks and benefits. Work history and educational background may be associated with postmenopausal muscle performance, which itself has unique associations with skeletal and cardiovascular diseases.

  1. Overview of the Muscle Cytoskeleton

    Science.gov (United States)

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

    2018-01-01

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

  2. Immunology Guides Skeletal Muscle Regeneration

    Directory of Open Access Journals (Sweden)

    F. Andrea Sass

    2018-03-01

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

  3. Muscle regeneration in mitochondrial myopathies

    DEFF Research Database (Denmark)

    Krag, T O; Hauerslev, S; Jeppesen, T D

    2013-01-01

    Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial...... myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected...

  4. Glycogen synthesis in human gastrocnemius muscle is not representative of whole-body muscle glycogen synthesis.

    NARCIS (Netherlands)

    Serlie, M.J.; Haan, J.H.A. de; Tack, C.J.J.; Verberne, H.J.; Ackermans, M.T.; Heerschap, A.; Sauerwein, H.P.

    2005-01-01

    The introduction of 13C magnetic resonance spectroscopy (MRS) has enabled noninvasive measurement of muscle glycogen synthesis in humans. Conclusions based on measurements by the MRS technique assume that glucose metabolism in gastrocnemius muscle is representative for all skeletal muscles and thus

  5. Glycogen synthesis in human gastrocnemius muscle is not representative of whole-body muscle glycogen synthesis

    NARCIS (Netherlands)

    Serlie, Mireille J. M.; de Haan, Jacco H.; Tack, Cees J.; Verberne, Hein J.; Ackermans, Mariette T.; Heerschap, Arend; Sauerwein, Hans P.

    2005-01-01

    The introduction of C-13 magnetic resonance spectroscopy (MRS) has enabled noninvasive measurement of muscle glycogen synthesis in humans. Conclusions based on measurements by the MRS technique assume that glucose metabolism in gastrocnemius muscle is representative for all skeletal muscles and thus

  6. Muscle MRI findings in facioscapulohumeral muscular dystrophy

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-15

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

  7. Dietary cinnamaldehyde enhances acquisition of specific antibodies following helminth infection in pigs

    DEFF Research Database (Denmark)

    Williams, Andrew R.; Hansen, Tina V. A.; Krych, Lukasz

    2017-01-01

    immune responses during infection with an enteric pathogen. We examined the effect of dietary CA on plasma antibody levels in parasite-naïve pigs, and subsequently acquisition of humoral immune responses during infection with the parasitic nematode Ascaris suum. Parasite-naïve pigs fed diets supplemented...... with CA had higher levels of total IgA and IgG in plasma, and A. suum-infected pigs fed CA had higher levels of parasite-specific IgM and IgA in plasma 14days post-infection. Moreover, dietary CA increased expression of genes encoding the B-cell marker CD19, sodium/glucose co-transporter1 (SCA5L1...

  8. Partial muscle carnitine palmitoyltransferase-A deficiency

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-01-02

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

  9. Partial muscle carnitine palmitoyltransferase-A deficiency

    International Nuclear Information System (INIS)

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

    1987-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Somayeh Amiri Arimi

    2012-07-01

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

  11. Determining the influence of muscle operating length on muscle performance during frog swimming using a bio-robotic model

    International Nuclear Information System (INIS)

    Clemente, Christofer J; Richards, Christopher

    2012-01-01

    Frogs are capable of impressive feats of jumping and swimming. Recent work has shown that anuran hind limb muscles can operate at lengths longer than the ‘optimal length’. To address the implications of muscle operating length on muscle power output and swimming mechanics, we built a robotic frog hind limb model based upon Xenopus laevis. The model simulated the force–length and force–velocity properties of vertebrate muscle, within the skeletal environment. We tested three muscle starting lengths, representing long, optimal and short starting lengths. Increasing starting length increased maximum muscle power output by 27% from 98.1 W kg −1 when muscle begins shortening from the optimal length, to 125.1 W kg −1 when the muscle begins at longer initial lengths. Therefore, longer starting lengths generated greater hydrodynamic force for extended durations, enabling faster swimming speeds of the robotic frog. These swimming speeds increased from 0.15 m s −1 at short initial muscle lengths, to 0.39 m s −1 for the longest initial lengths. Longer starting lengths were able to increase power as the muscle's force–length curve was better synchronized with the muscle's activation profile. We further dissected the underlying components of muscle force, separating force–length versus force–velocity effects, showing a transition from force–length limitations to force–velocity limitations as starting length increased. (paper)

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

    Science.gov (United States)

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

    2017-03-01

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

  13. Muscle-specific integrins in masseter muscle fibers of chimpanzees: an immunohistochemical study.

    Directory of Open Access Journals (Sweden)

    Gianluigi Vaccarino

    2010-05-01

    Full Text Available Most notably, recent comparative genomic analyses strongly indicate that the marked differences between modern human and chimpanzees are likely due more to changes in gene regulation than to modifications of the genes. The most peculiar aspect of hominoid karyotypes is that human have 46 chromosomes whereas gorillas and chimpanzees have 48. Interestingly, human and chimpanzees do share identical inversions on chromosome 7 and 9 that are not evident in the gorilla karyotype. Thus, the general phylogeny suggests that humans and chimpanzees are sister taxa; based on this, it seems that human-chimpanzee sequence similarity is an astonishing 99%. At this purpose, of particular interest is the inactivation of the myosin heavy chain 16 (MYH16 gene, most prominently expressed in the masticatory muscle of mammals. It has been showed that the loss of this gene in humans may have resulted in smaller masticatory muscle and consequential changes to cranio-facial morphology and expansion of the human brain case. Powerful masticatory muscles are found in most primates; contrarily, in both modern and fossil member Homo, these muscles are considerably smaller. The evolving hominid masticatory apparatus shifted towards a pattern of gracilization nearly simultaneously with accelerated encephalization in early Homo. To better comprehend the real role of the MYH16 gene, we studied the primary proteins present in the muscle fibers of humans and non-humans, in order to understand if they really can be influenced by MYH16 gene. At this aim we examined the muscle-specific integrins, alpha 7B and beta 1D-integrins, and their relative fetal isoforms, alpha 7A and beta 1A-integrins, analyzing, by immunohistochemistry, muscle biopsies of two components of a chimpanzee's group in captivity, an alpha male and a non-alpha male subjects; all these integrins participate in vital biological processes such as maintenance of tissue integrity, embryonic development, cell

  14. [Nosological classification and assessment of muscle dysmorphia].

    Science.gov (United States)

    Babusa, Bernadett; Túry, Ferenc

    2011-01-01

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

  15. Comparative anatomy and muscle architecture of selected hind limb muscles in the Quarter Horse and Arab.

    Science.gov (United States)

    Crook, T C; Cruickshank, S E; McGowan, C M; Stubbs, N; Wakeling, J M; Wilson, A M; Payne, R C

    2008-02-01

    The Quarter Horse (bred for acceleration) and the Arab (bred for endurance) are situated at either end of the equine athletic spectrum. Studies into the form and function of the leg muscles in human sprint and endurance runners have demonstrated that differences exist in their muscle architecture. It is not known whether similar differences exist in the horse. Six Quarter Horse and six Arab fresh hind limb cadavers were dissected to gain information on the muscle mass and architecture of the following muscles: gluteus medius; biceps femoris; semitendinosus; vastus lateralis; gastrocnemius; tibialis cranialis and extensor digitorum longus. Specifically, muscle mass, fascicle length and pennation angle were quantified and physiological cross-sectional area (PCSA) and maximum isometric force were estimated. The hind limb muscles of the Quarter Horse were of a significantly greater mass, but had similar fascicle lengths and pennation angles when compared with those of the Arab; this resulted in the Quarter Horse hind limb muscles having greater PCSAs and hence greater isometric force potential. This study suggests that Quarter Horses as a breed inherently possess large strong hind limb muscles, with the potential to accelerate their body mass more rapidly than those of the Arab.

  16. In Graves' disease, increased muscle tension and reduced elasticity of affected muscles is primarily caused by active muscle contraction

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); G. Kommerell (Guntram)

    1989-01-01

    textabstractIn three patients with Graves' disease of recent onset, length-tension diagrams were made during surgery for squint under eyedrop anesthesia, while the other eye looked ahead, into the field of action, or out of the field of action of the muscle that was measured. The affected muscles

  17. Exercise-induced muscle modifications

    International Nuclear Information System (INIS)

    Kerviler, E. de; Willig, A.L.; Jehenson, P.; Duboc, D.; Syrota, A.

    1990-01-01

    This paper compares changes in muscle proton T2 after exercise in normal subjects and in patients with muscular glycogenoses. Four patients suffering from muscular glycogenosis and eight normal volunteers were studied. Muscle T2s were measured in forearm muscles at rest and after exercise, with a 0.5-T imager. The exercise was performed with handgrips and was evaluated by P-31 spectroscopy (end-exercise decrease in pH and phosphocreatine) performed with a 2-T magnet. In normal subjects, a relative T2 increase, ranging from 14% to 44%, was observed in the exercised muscles. In the patients, who cannot produce lactate during exercise, weak pH variation occurred, and only a slight T2 increase (7% - 9%) was observed

  18. Water and Muscle Contraction

    Directory of Open Access Journals (Sweden)

    Enrico Grazi

    2008-08-01

    Full Text Available The interaction between water and the protein of the contractile machinery as well as the tendency of these proteins to form geometrically ordered structures provide a link between water and muscle contraction. Protein osmotic pressure is strictly related to the chemical potential of the contractile proteins, to the stiffness of muscle structures and to the viscosity of the sliding of the thin over the thick filaments. Muscle power output and the steady rate of contraction are linked by modulating a single parameter, a viscosity coefficient. Muscle operation is characterized by working strokes of much shorter length and much quicker than in the classical model. As a consequence the force delivered and the stiffness attained by attached cross-bridges is much larger than usually believed.

  19. Beta-hydroxy-beta-methylbutyrate supplementation and skeletal muscle in healthy and muscle-wasting conditions.

    Science.gov (United States)

    Holeček, Milan

    2017-08-01

    Beta-hydroxy-beta-methylbutyrate (HMB) is a metabolite of the essential amino acid leucine that has been reported to have anabolic effects on protein metabolism. The aims of this article were to summarize the results of studies of the effects of HMB on skeletal muscle and to examine the evidence for the rationale to use HMB as a nutritional supplement to exert beneficial effects on muscle mass and function in various conditions of health and disease. The data presented here indicate that the beneficial effects of HMB have been well characterized in strength-power and endurance exercise. HMB attenuates exercise-induced muscle damage and enhances muscle hypertrophy and strength, aerobic performance, resistance to fatigue, and regenerative capacity. HMB is particularly effective in untrained individuals who are exposed to strenuous exercise and in trained individuals who are exposed to periods of high physical stress. The low effectiveness of HMB in strength-trained athletes could be due to the suppression of the proteolysis that is induced by the adaptation to training, which may blunt the effects of HMB. Studies performed with older people have demonstrated that HMB can attenuate the development of sarcopenia in elderly subjects and that the optimal effects of HMB on muscle growth and strength occur when it is combined with exercise. Studies performed under in vitro conditions and in various animal models suggest that HMB may be effective in treatment of muscle wasting in various forms of cachexia. However, there are few clinical reports of the effects of HMB on muscle wasting in cachexia; in addition, most of these studies evaluated the therapeutic potential of combinations of various agents. Therefore, it has not been possible to determine whether HMB was effective or if there was a synergistic effect. Although most of the endogenous HMB is produced in the liver, there are no reports regarding the levels and the effects of HMB supplementation in subjects with

  20. Myoglobin plasma level related to muscle mass and fiber composition: a clinical marker of muscle wasting?

    Science.gov (United States)

    Weber, Marc-André; Kinscherf, Ralf; Krakowski-Roosen, Holger; Aulmann, Michael; Renk, Hanna; Künkele, Annette; Edler, Lutz; Kauczor, Hans-Ulrich; Hildebrandt, Wulf

    2007-08-01

    Progressive muscle wasting is a central feature of cancer-related cachexia and has been recognized as a determinant of poor prognosis and quality of life. However, until now, no easily assessable clinical marker exists that allows to predict or to track muscle wasting. The present study evaluated the potential of myoglobin (MG) plasma levels to indicate wasting of large locomotor muscles and, moreover, to reflect the loss of MG-rich fiber types, which are most relevant for daily performance. In 17 cancer-cachectic patients (weight loss 22%) and 27 age- and gender-matched healthy controls, we determined plasma levels of MG and creatine kinase (CK), maximal quadriceps muscle cross-sectional area (CSA) by magnetic resonance imaging, muscle morphology and fiber composition in biopsies from the vastus lateralis muscle, body cell mass (BCM) by impedance technique as well as maximal oxygen uptake (VO(2)max). In cachectic patients, plasma MG, muscle CSA, BCM, and VO(2)max were 30-35% below control levels. MG showed a significant positive correlation to total muscle CSA (r = 0.65, p max as an important functional readout. CK plasma levels appear to be less reliable because prolonged increases are observed in even subclinical myopathies or after exercise. Notably, cancer-related muscle wasting was not associated with increases in plasma MG or CK in this study.

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

    Science.gov (United States)

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

    2007-08-01

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

  2. Diabetic muscle infarction: atypical MR appearance

    International Nuclear Information System (INIS)

    Sharma, P.; Mangwana, S.; Kapoor, R.K.

    2000-01-01

    We describe a case of diabetic muscle infarction which had atypical features of hyperintensity of the affected muscle on T1-weighted images. Biopsy was performed which revealed diffuse extensive hemorrhage within the infarcted muscle. We believe increased signal intensity on T1-weighted images should suggest hemorrhage within the infarcted muscle. (orig.)

  3. MR imaging of muscle diseases

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  4. Muscle wasting and resistance of muscle anabolism: the "anabolic threshold concept" for adapted nutritional strategies during sarcopenia.

    Science.gov (United States)

    Dardevet, Dominique; Rémond, Didier; Peyron, Marie-Agnès; Papet, Isabelle; Savary-Auzeloux, Isabelle; Mosoni, Laurent

    2012-01-01

    Skeletal muscle loss is observed in several physiopathological situations. Strategies to prevent, slow down, or increase recovery of muscle have already been tested. Besides exercise, nutrition, and more particularly protein nutrition based on increased amino acid, leucine or the quality of protein intake has generated positive acute postprandial effect on muscle protein anabolism. However, on the long term, these nutritional strategies have often failed in improving muscle mass even if given for long periods of time in both humans and rodent models. Muscle mass loss situations have been often correlated to a resistance of muscle protein anabolism to food intake which may be explained by an increase of the anabolic threshold toward the stimulatory effect of amino acids. In this paper, we will emphasize how this anabolic resistance may affect the intensity and the duration of the muscle anabolic response at the postprandial state and how it may explain the negative results obtained on the long term in the prevention of muscle mass. Sarcopenia, the muscle mass loss observed during aging, has been chosen to illustrate this concept but it may be kept in mind that it could be extended to any other catabolic states or recovery situations.

  5. Transmission Electron Microscopy of the Gastrointestinal Tract of Nile Perch Lates niloticus

    OpenAIRE

    Namulawa, V. T; Kato, C. D; Nyatia, E; Rutaisire, J; Britz, P. J

    2015-01-01

    The ultrastructure of the gastrointestinal tract of Nile perch was described using Transmission Electron Microscopy standard procedures. Investigations revealed the presence of mucous cells, blood vessels and oil droplets plus several nerve cells and muscle bundles in the oral cavity. Further observations revealed columnar epithelial cells in the oesophagus, with a ragged surface, high electron dense cytoplasm, intercellular spaces, mitochondria and mucus granules. The lamina propria of the o...

  6. Muscle Synergy-Driven Robust Motion Control.

    Science.gov (United States)

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

    2018-04-01

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

  7. Nutritional interventions to preserve skeletal muscle mass

    NARCIS (Netherlands)

    Backx, Evelien M.P.

    2016-01-01

    Muscle mass is the main predictor for muscle strength and physical function. The amount of muscle mass can decline rapidly during periods of reduced physical activity or during periods of energy intake restriction. For athletes, it is important to maintain muscle mass, since the loss of muscle is

  8. Muscle Atrophy Reversed by Growth Factor Activation of Satellite Cells in a Mouse Muscle Atrophy Model

    DEFF Research Database (Denmark)

    Hauerslev, Simon; Vissing, John; Krag, Thomas O

    2014-01-01

    mechanism that may contribute to the progressive muscle wasting seen in severely affected patients with muscular dystrophy and significant on-going regeneration. This treatment could potentially be applied to many conditions that feature muscle wasting to increase muscle bulk and strength.......Muscular dystrophies comprise a large group of inherited disorders that lead to progressive muscle wasting. We wanted to investigate if targeting satellite cells can enhance muscle regeneration and thus increase muscle mass. We treated mice with hepatocyte growth factor and leukemia inhibitory...... factor under three conditions: normoxia, hypoxia and during myostatin deficiency. We found that hepatocyte growth factor treatment led to activation of the Akt/mTOR/p70S6K protein synthesis pathway, up-regulation of the myognic transcription factors MyoD and myogenin, and subsequently the negative growth...

  9. Bio-inspired Hybrid Carbon Nanotube Muscles

    Science.gov (United States)

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

    2016-05-01

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2008-04-01

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

  12. In cirrhotic patients reduced muscle strength is unrelated to muscle capacity for ATP turnover suggesting a central limitation

    DEFF Research Database (Denmark)

    Gam, Christiane Marie Bourgin; Nielsen, H B; Secher, Niels H.

    2011-01-01

      We investigated whether in patients with liver cirrhosis reduced muscle strength is related to dysfunction of muscle mitochondria.......  We investigated whether in patients with liver cirrhosis reduced muscle strength is related to dysfunction of muscle mitochondria....

  13. in Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Espen E. Spangenburg

    2011-01-01

    Full Text Available Triglyceride storage is altered across various chronic health conditions necessitating various techniques to visualize and quantify lipid droplets (LDs. Here, we describe the utilization of the BODIPY (493/503 dye in skeletal muscle as a means to analyze LDs. We found that the dye was a convenient and simple approach to visualize LDs in both sectioned skeletal muscle and cultured adult single fibers. Furthermore, the dye was effective in both fixed and nonfixed cells, and the staining seemed unaffected by permeabilization. We believe that the use of the BODIPY (493/503 dye is an acceptable alternative and, under certain conditions, a simpler method for visualizing LDs stored within skeletal muscle.

  14. Foot muscles strengthener

    Directory of Open Access Journals (Sweden)

    Boris T. Glavač

    2012-04-01

    Full Text Available Previous experience in the correction of flat feet consisted of the use of insoles for shoes and exercises with toys, balls, rollers, inclined planes, etc. A device for strengthening foot muscles is designed for the correction of flat feet in children and, as its name suggests, for strengthening foot muscles in adults. The device is made of wood and metal, with a mechanism and technical solutions, enabling the implementation of specific exercises to activate muscles responsible for the formation of the foot arch. It is suitable for home use with controlled load quantities since it has calibrated springs. The device is patented with the Intellectual Property Office, Republic of Serbia, as a petty patent.

  15. Anti-smooth muscle antibody

    Science.gov (United States)

    ... gov/ency/article/003531.htm Anti-smooth muscle antibody To use the sharing features on this page, please enable JavaScript. Anti-smooth muscle antibody is a blood test that detects the presence ...

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

    DEFF Research Database (Denmark)

    Pingel, Jessica; Wienecke, Jacob; Lorentzen, Jakob

    2016-01-01

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

  17. Nuclear Positioning in Muscle Development and Disease

    Directory of Open Access Journals (Sweden)

    Eric eFolker

    2013-12-01

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

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

    Science.gov (United States)

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

    2017-05-01

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

  19. Fluid-driven origami-inspired artificial muscles

    Science.gov (United States)

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

    2017-12-01

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

  20. Exercising with blocked muscle glycogenolysis

    DEFF Research Database (Denmark)

    Nielsen, Tue L; Pinós, Tomàs; Brull, Astrid

    2018-01-01

    BACKGROUND: McArdle disease (glycogen storage disease type V) is an inborn error of skeletal muscle metabolism, which affects glycogen phosphorylase (myophosphorylase) activity leading to an inability to break down glycogen. Patients with McArdle disease are exercise intolerant, as muscle glycogen......-derived glucose is unavailable during exercise. Metabolic adaptation to blocked muscle glycogenolysis occurs at rest in the McArdle mouse model, but only in highly glycolytic muscle. However, it is unknown what compensatory metabolic adaptations occur during exercise in McArdle disease. METHODS: In this study, 8......-week old McArdle and wild-type mice were exercised on a treadmill until exhausted. Dissected muscles were compared with non-exercised, age-matched McArdle and wild-type mice for histology and activation and expression of proteins involved in glucose uptake and glycogenolysis. RESULTS: Investigation...

  1. Muscle dysfunction in cancer patients

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2011-02-03

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

  3. Skeletal muscle performance and ageing.

    Science.gov (United States)

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

    2018-02-01

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

  4. Loss of the inducible Hsp70 delays the inflammatory response to skeletal muscle injury and severely impairs muscle regeneration.

    Directory of Open Access Journals (Sweden)

    Sarah M Senf

    Full Text Available Skeletal muscle regeneration following injury is a highly coordinated process that involves transient muscle inflammation, removal of necrotic cellular debris and subsequent replacement of damaged myofibers through secondary myogenesis. However, the molecular mechanisms which coordinate these events are only beginning to be defined. In the current study we demonstrate that Heat shock protein 70 (Hsp70 is increased following muscle injury, and is necessary for the normal sequence of events following severe injury induced by cardiotoxin, and physiological injury induced by modified muscle use. Indeed, Hsp70 ablated mice showed a significantly delayed inflammatory response to muscle injury induced by cardiotoxin, with nearly undetected levels of both neutrophil and macrophage markers 24 hours post-injury. At later time points, Hsp70 ablated mice showed sustained muscle inflammation and necrosis, calcium deposition and impaired fiber regeneration that persisted several weeks post-injury. Through rescue experiments reintroducing Hsp70 intracellular expression plasmids into muscles of Hsp70 ablated mice either prior to injury or post-injury, we confirm that Hsp70 optimally promotes muscle regeneration when expressed during both the inflammatory phase that predominates in the first four days following severe injury and the regenerative phase that predominates thereafter. Additional rescue experiments reintroducing Hsp70 protein into the extracellular microenvironment of injured muscles at the onset of injury provides further evidence that Hsp70 released from damaged muscle may drive the early inflammatory response to injury. Importantly, following induction of physiological injury through muscle reloading following a period of muscle disuse, reduced inflammation in 3-day reloaded muscles of Hsp70 ablated mice was associated with preservation of myofibers, and increased muscle force production at later time points compared to WT. Collectively our

  5. Separation and estimation of muscle spindle and tension receptor populations by vibration of the biceps muscle in the frog.

    Science.gov (United States)

    Giszter, S F; Kargo, W J

    2002-10-01

    Frog spinal cord reflex behaviors have been used to test the idea of spinal primitives. We have suggested a significant role for proprioception in regulation of primitives. However the in vivo behavior of spindle and golgi tendon receptors in frogs in response to vibration are not well described and the proportions of these proprioceptors are not established. In this study, we examine the selectivity of muscle vibration in the spinal frog. The aim of the study was (1) to examine how hindlimb muscle spindles and GTO receptors are activated by muscle vibration and (2) to estimate the relative numbers of GTO receptors and spindle afferents in a selected muscle, for comparison with the mammal. Single muscle afferents from the biceps muscle were identified in the dorsal roots. These were tested in response to biceps vibration, intramuscular stimulation and biceps nerve stimulation. Biceps units were categorized into two types: First, spindle afferents which had a high conduction velocity (approximately 20-30 m/s), responded reliably (were entrained 1:1) to muscle vibration, and exhibited distinct pauses to shortening muscle contractions. Second, golgi tendon organ afferents, which had a lower conduction velocity (approximately 10-20 m/s), responded less reliably to muscle vibration at physiologic muscle lengths, but responded more reliably at extended lengths or with background muscle contraction, and exhibited distinct bursts to shortening muscle contractions. Vibration responses of these units were tested with and without muscle curarization. Ensemble (suction electrode) recordings from the dorsal roots were used to provide rough estimates of the proportions of the two muscle afferent types.

  6. Variability of femoral muscle attachments.

    Science.gov (United States)

    Duda, G N; Brand, D; Freitag, S; Lierse, W; Schneider, E

    1996-09-01

    Analytical and experimental models of the musculoskeletal system often assume single values rather than ranges for anatomical input parameters. The hypothesis of the present study was that anatomical variability significantly influences the results of biomechanical analyses, specifically regarding the moment arms of the various thigh muscles. Insertions and origins of muscles crossing or attaching to the femur were digitized in six specimens. Muscle volumes were measured; muscle attachment area and centroid location were computed. To demonstrate the influence of inter-individual anatomic variability on a mechanical modeling parameter, the corresponding range of muscle moment arms were calculated. Standard deviations, as a percentage of the mean, were about 70% for attachment area and 80% for muscle volume and attachment centroid location. The resulting moment arms of the m. gluteus maximus and m. rectus femoris were especially sensitive to anatomical variations (SD 65%). The results indicate that sensitivity to anatomical variations should be analyzed in any investigation simulating musculoskeletal interactions. To avoid misinterpretations, investigators should consider using several anatomical configurations rather than relying on a mean data set.

  7. Muscle histochemistry in chronic alcoholism

    Directory of Open Access Journals (Sweden)

    M. L. Ferraz

    1989-06-01

    Full Text Available Twenty-two chronic acoholic patients were assessed by neurologic examination and muscle biopsy. The patients manifested proximal muscular weakness to a variable extent. One case presented as an acute bout of myopathy, according to the Manual Muscle Test, MMT. The most prominent histologic feature observed was muscle atrophy (95.3% better evidenced through the ATPase stain with the predominance of type II A fibers (71.4%. Lack of the mosaic pattern (type grouping seen in 76% of the cases and an important mitochondrial proliferation with intrasarcoplasmatic lipid accumulation in 63% of the patients. In case of acute presentation of muscle weakness the. pathological substrate is quite different, i.e. presence of myositis mainly interstitial characterized by lymphoplasmocytic infiltrate and several spots of necrosis like Zencker degeneration. Based on histologic criteria, our data suggest that: the main determinant of muscle weakness seen in chronic alcoholic patients is neurogenic in origin (alcoholic polineuropathy; the direct toxic action of ethanol under the skeletal muscle is closely related to the mitochondrial metabolism; the so-called acute alcoholic myopathy has probably viral etiology.

  8. A Systematic Review and Meta-Analysis of Proteomics Literature on the Response of Human Skeletal Muscle to Obesity/Type 2 Diabetes Mellitus (T2DM) Versus Exercise Training.

    Science.gov (United States)

    Srisawat, Kanchana; Shepherd, Sam O; Lisboa, Paulo J; Burniston, Jatin G

    2017-11-11

    We performed a systematic review and meta-analysis of proteomics literature that reports human skeletal muscle responses in the context of either pathological decline associated with obesity/T2DM and physiological adaptations to exercise training. Literature was collected from PubMed and DOAJ databases following PRISMA guidelines using the search terms 'proteom*', and 'skeletal muscle' combined with either 'obesity, insulin resistance, diabetes, impaired glucose tolerance' or 'exercise, training'. Eleven studies were included in the systematic review, and meta-analysis was performed on a sub-set (four studies) of the reviewed literature that reported the necessary primary data. The majority of proteins ( n = 73) more abundant in the muscle of obese/T2DM individuals were unique to this group and not reported to be responsive to exercise training. The main response of skeletal muscle to exercise training was a greater abundance of proteins of the mitochondrial electron transport chain, tricarboxylic acid cycle and mitochondrial respiratory chain complex I assembly. In total, five proteins were less abundant in muscle of obese/T2DM individuals and were also reported to be more abundant in the muscle of endurance-trained individuals, suggesting one of the major mechanisms of exercise-induced protection against the deleterious effects of obesity/T2DM occurs at complex I of the electron transport chain.

  9. The exercised skeletal muscle: a review

    Directory of Open Access Journals (Sweden)

    Marina Marini

    2010-09-01

    Full Text Available The skeletal muscle is the second more plastic tissue of the body - second to the nervous tissue only. In fact, both physical activity and inactivity contribute to modify the skeletal muscle, by continuous signaling through nerve impulses, mechanical stimuli and humoral clues. In turn, the skeletal muscle sends signals to the body, thus contributing to its homeostasis. We'll review here the contribute of physical exercise to the shaping of skeletal muscle, to the adaptation of its mass and function to the different needs imposed by different physical activities and to the attainment of the health benefits associated with active skeletal muscles. Focus will primarily be on the molecular pathways and on gene regulation that result in skeletal muscle adaptation to exercise.

  10. Skeletal muscle weakness in osteogenesis imperfecta mice.

    Science.gov (United States)

    Gentry, Bettina A; Ferreira, J Andries; McCambridge, Amanda J; Brown, Marybeth; Phillips, Charlotte L

    2010-09-01

    Exercise intolerance, muscle fatigue and weakness are often-reported, little-investigated concerns of patients with osteogenesis imperfecta (OI). OI is a heritable connective tissue disorder hallmarked by bone fragility resulting primarily from dominant mutations in the proα1(I) or proα2(I) collagen genes and the recently discovered recessive mutations in post-translational modifying proteins of type I collagen. In this study we examined the soleus (S), plantaris (P), gastrocnemius (G), tibialis anterior (TA) and quadriceps (Q) muscles of mice expressing mild (+/oim) and moderately severe (oim/oim) OI for evidence of inherent muscle pathology. In particular, muscle weight, fiber cross-sectional area (CSA), fiber type, fiber histomorphology, fibrillar collagen content, absolute, relative and specific peak tetanic force (P(o), P(o)/mg and P(o)/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased P(o) and an inability to sustain P(o) for the 300-ms testing duration for specific muscles; +/oim mice had a similar but milder skeletal muscle phenotype. +/oim mice had mild weakness of specific muscles but were less affected than their oim/oim counterparts which demonstrated readily apparent skeletal muscle pathology. Therefore muscle weakness in oim mice reflects inherent skeletal muscle pathology. Copyright © 2010 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Science.gov (United States)

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

    2000-04-01

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

  13. Electrically induced muscle cramps induce hypertrophy of calf muscles in healthy adults.

    Science.gov (United States)

    Behringer, M; Moser, M; Montag, J; McCourt, M; Tenner, D; Mester, J

    2015-06-01

    Skeletal muscles usually cramp at short lengths, where the tension that can be exerted by muscle fibers is low. Since high tension is an important anabolic stimulus, it is questionable if cramps can induce hypertrophy and strength gains. In the present study we investigated if electrically induced cramps (EIMCs) can elicit these adaptations. 15 healthy male adults were randomly assigned to an intervention (IG; n=10) and a control group (CG; n=5). The cramp protocol (CP) applied twice a week to one leg of the IG, consisted of 3x6 EIMCs, of 5 s each. Calf muscles of the opposite leg were stimulated equally, but were hindered from cramping by fixating the ankle at 0° plantar flexion (nCP). After six weeks, the cross sectional area of the triceps surae was similarly increased in both the CP (+9.0±3.4%) and the nCP (+6.8±3.7%). By contrast, force of maximal voluntary contractions, measured at 0° and 30° plantar flexion, increased significantly only in nCP (0°: +8.5±8.8%; 30°: 11.7±13.7%). The present data indicate that muscle cramps can induce hypertrophy in calf muscles, though lacking high tension as an important anabolic stimulus.

  14. Cellular and molecular mechanisms of muscle atrophy

    Directory of Open Access Journals (Sweden)

    Paolo Bonaldo

    2013-01-01

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

  15. Comparative studies on Pb and Cd levels in parasites of terrestrial and aquatic animals

    Energy Technology Data Exchange (ETDEWEB)

    Sures, B.; Taraschewski, H. [Univ. Karlsruhe (Germany). Zoologisches Institut-Okologie

    1995-12-31

    Several fish parasites (Acanthocephala, Cestoda, Nematoda) and organs of their respective intermediate and final hosts were analyzed for heavy metals by electrothermal atomic absorption spectrometry (ET-AAS). Pb and Cd were also quantified in the liver fluke Fasciola hepatica as well as in different organs of the large intestinal roundworm Ascaris suum. The levels of these heavy metals in the parasites were compared to those of muscle, liver, kidney and intestine of the respective definitive hosts cattle and swine obtained from a slaughter house. Most parasites accumulated significantly higher levels of metals than their final hosts. This was most conspicuous in acanthocephalans which contained up to 3 {times} 10{sup 3} fold more lead than the muscle of their fish hosts and up to 1.1 {times} 10{sup 4} more lead than the water surrounding the fish. In these helminths cadmium was enriched up to 400 fold compared to the muscle of the fish and up to 2.7 {times} 10{sup 4} compared to the water. In contrast to the accumulation capacity of adult acanthocephalans their larvae contained about 30 to 180 times less Pb and Cd. Thus, the predominant accumulation of both metals appears in the adult worms. The cestodes of fish and the liver flukes of cattle accumulated the metals up to 200 fold compared to the muscle of their hosts. The nematodes did not contain higher levels of the metals than their hosts. Thus, parasites, especially acanthocephalans, seem to be sensitive bioindicators of Pb and Cd in their environments.

  16. Preserving Healthy Muscle during Weight Loss123

    Science.gov (United States)

    Cava, Edda; Yeat, Nai Chien; Mittendorfer, Bettina

    2017-01-01

    Weight loss is the cornerstone of therapy for people with obesity because it can ameliorate or completely resolve the metabolic risk factors for diabetes, coronary artery disease, and obesity-associated cancers. The potential health benefits of diet-induced weight loss are thought to be compromised by the weight-loss–associated loss of lean body mass, which could increase the risk of sarcopenia (low muscle mass and impaired muscle function). The objective of this review is to provide an overview of what is known about weight-loss–induced muscle loss and its implications for overall physical function (e.g., ability to lift items, walk, and climb stairs). The currently available data in the literature show the following: 1) compared with persons with normal weight, those with obesity have more muscle mass but poor muscle quality; 2) diet-induced weight loss reduces muscle mass without adversely affecting muscle strength; 3) weight loss improves global physical function, most likely because of reduced fat mass; 4) high protein intake helps preserve lean body and muscle mass during weight loss but does not improve muscle strength and could have adverse effects on metabolic function; 5) both endurance- and resistance-type exercise help preserve muscle mass during weight loss, and resistance-type exercise also improves muscle strength. We therefore conclude that weight-loss therapy, including a hypocaloric diet with adequate (but not excessive) protein intake and increased physical activity (particularly resistance-type exercise), should be promoted to maintain muscle mass and improve muscle strength and physical function in persons with obesity. PMID:28507015

  17. Fluid-driven origami-inspired artificial muscles.

    Science.gov (United States)

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

    2017-12-12

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

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

    DEFF Research Database (Denmark)

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

    1996-01-01

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

  19. The characteristics of a pneumatic muscle

    OpenAIRE

    Pietrala Dawid

    2017-01-01

    The article presents static and dynamic characteristics of pneumatic muscles. It presents the structure of the laboratory stand used to test pneumatic muscles. It discusses the methodology for determination of static and dynamic characteristics. The paper also illustrates characteristics showing the relationship of pneumatic muscles length and operating pressure, at a constant loading force (isotonic characteristics). It presents characteristics showing the relationship of pneumatic muscles s...

  20. Gender differences in MR muscle tractography

    International Nuclear Information System (INIS)

    Okamoto, Yoshikazu; Minami, Manabu; Kunimatsu, Akira; Kono, Tatsuo; Sonobe, Jyunichi; Kujiraoka, Yuka

    2010-01-01

    Tractography of skeletal muscle can clearly reveal the 3-dimensional course of muscle fibers, and the procedure has great potential and could open new fields for diagnostic imaging. Studying this technique for clinical application, we noticed differences in the number of visualized tracts among volunteers and among muscles in the same volunteer. To comprehend why the number of visualized tracts varied so that we could acquire consistently high quality tractography of muscle fiber, we started to examine whether differences in individual parameters affected tractography visualization. The purpose of this study was to determine whether there are gender- and age-specific differences that differentiate the muscles by gender and age in MR tractography of skeletal muscle fiber. We divided 33 healthy volunteers by gender and age among 3 groups, A (13 younger men, aged 20 to 36 years), B (11 younger women, 25 to 39 years), and C (9 older men, 50 to 69), and we obtained from each volunteer tractographs of 8 fibers, including the bilateral gastrocnemius medialis (GCM), gastrocnemius lateralis (GCL), soleus (SOL), and anterior tibialis (AT) muscles. We classified the fibers into 5 grades depending on the extent of visualized tracts and used Mann-Whitney U-test to compare scores by gender (Group A versus B) and age (Group A versus C). Muscle tracts were significantly better visualized in women than men (median total visual score, 34 versus 24, P<0.05). In particular, the SOL muscles showed better visualization in the right (4.0 in women, 1.0 in men, P<0.05) and left (3.0 in women, 1.0 in men, P<0.05). Difference by age was not significant. The GCL was the highest scored muscle in all groups. Our results suggest that group differences, especially by gender, affected visualization of tractography of muscle fiber of the calf. (author)

  1. Dual role of delta-like 1 homolog (DLK1) in skeletal muscle development and adult muscle regeneration

    DEFF Research Database (Denmark)

    Andersen, Ditte Caroline; Laborda, Jorge; Baladron, Victoriano

    2013-01-01

    skeletal muscle regeneration by substantial enhancement of the myogenic program and muscle function, possibly by means of an increased number of available myogenic precursor cells. By contrast, Dlk1 fails to alter the adipogenic commitment of muscle-derived progenitors in vitro, as well as intramuscular......Muscle development and regeneration is tightly orchestrated by a specific set of myogenic transcription factors. However, factors that regulate these essential myogenic inducers remain poorly described. Here, we show that delta-like 1 homolog (Dlk1), an imprinted gene best known for its ability...... fat deposition during in vivo regeneration. Collectively, our results suggest a novel and surprising dual biological function of DLK1 as an enhancer of muscle development, but as an inhibitor of adult muscle regeneration....

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

    Science.gov (United States)

    Zhang, Jing; Liu, Yu Lan

    2017-01-01

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

  3. 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

  4. Leiomyoma of the sternothyroid muscle.

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2002-12-01

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

  6. THE RENIN-ANGIOTENSIN SYSTEM AND THE BIOLOGY OF SKELETAL MUSCLE: MECHANISMS OF MUSCLE WASTING IN CHRONIC DISEASE STATES.

    Science.gov (United States)

    Delafontaine, Patrice; Yoshida, Tadashi

    2016-01-01

    Sarcopenia and cachexia are muscle-wasting syndromes associated with aging and with many chronic diseases such as congestive heart failure, diabetes, cancer, chronic obstructive pulmonary disease, and renal failure. While mechanisms are complex, these conditions are often accompanied by elevated angiotensin II (Ang II). We found that Ang II infusion in rodents leads to skeletal muscle wasting via alterations in insulin-like growth factor-1 signaling, increased apoptosis, enhanced muscle protein breakdown via the ubiquitin-proteasome system, and decreased appetite resulting from downregulation of hypothalamic orexigenic neuropeptides orexin and neuropeptide Y. Furthermore, Ang II inhibits skeletal muscle stem cell proliferation, leading to lowered muscle regenerative capacity. Distinct stem cell Ang II receptor subtypes are critical for regulation of muscle regeneration. In ischemic mouse congestive heart failure model skeletal muscle wasting and attenuated muscle regeneration are Ang II dependent. These data suggest that the renin-angiotensin system plays a critical role in mechanisms underlying cachexia in chronic disease states.

  7. Muscles and their myokines

    DEFF Research Database (Denmark)

    Pedersen, Bente Klarlund

    2011-01-01

    In the past, the role of physical activity as a life-style modulating factor has been considered as that of a tool to balance energy intake. Although it is important to avoid obesity, physical inactivity should be discussed in a much broader context. There is accumulating epidemiological evidence...... or endocrine effects should be classified as 'myokines'. Given that skeletal muscle is the largest organ in the human body, our discovery that contracting skeletal muscle secretes proteins sets a novel paradigm: skeletal muscle is an endocrine organ producing and releasing myokines, which work in a hormone......-like fashion, exerting specific endocrine effects on other organs. Other myokines work via paracrine mechanisms, exerting local effects on signalling pathways involved in muscle metabolism. It has been suggested that myokines may contribute to exercise-induced protection against several chronic diseases....

  8. Assessment of muscle fatigue during biking.

    Science.gov (United States)

    Knaflitz, Marco; Molinari, Filippo

    2003-03-01

    The analysis of the surface myoelectric signal recorded while a muscle is performing a sustained contraction is a valuable tool for assessing the progression of localized fatigue. It is well known that the modifications of the spectral content of the myoelectric signal are mainly related to changes in the interstitial fluid pH, which, in turn, affect the membrane excitability of the active muscle fibers. This paper describes the effects of muscle fatigue on the surface myoelectric signal recorded from three thigh and leg muscles during biking, on a population consisting of 22 young healthy volunteers. The purpose of this study was to obtain normative data relative to an exercise protocol mild enough to be applicable, in the future, to pathological subjects as well. Each subject was asked to exercise 30 min on a cycloergometer at a constant velocity and against a constant torque. While subjects were biking, the surface myoelectric signal was recorded from the rectus femoris, the biceps femoris, and the gastrocnemius muscles. In this study, we considered two different aspects of muscle fatigue: first, the localized muscle fatigue as shown by the decrement of the instantaneous frequency of the myoelectric signal during the exercise; second, the modifications of the muscle ON-OFF timing, which could be explained as a strategy for increasing endurance by modifying the role of different muscles during the exercise. The first aspect was studied by obtaining the spectral characteristics of the signals by means of bilinear time-frequency transforms and by applying an original estimator of the instantaneous frequency of stochastic processes based on cross time-frequency transforms. Our results demonstrated that none of the subjects showed significant signs of localized muscle fatigue, since the decrement of the instantaneous frequency during the exercise was always lower than 5% of its initial value. Muscle ON-OFF timing was obtained by applying to the raw myoelectric signal

  9. Muscle channelopathies and electrophysiological approach

    Directory of Open Access Journals (Sweden)

    Cherian Ajith

    2008-01-01

    Full Text Available Myotonic syndromes and periodic paralyses are rare disorders of skeletal muscle characterized mainly by muscle stiffness or episodic attacks of weakness. Familial forms are caused by mutation in genes coding for skeletal muscle voltage ionic channels. Familial periodic paralysis and nondystrophic myotonias are disorders of skeletal muscle excitability caused by mutations in genes coding for voltage-gated ion channels. These diseases are characterized by episodic failure of motor activity due to muscle weakness (paralysis or stiffness (myotonia. Clinical studies have identified two forms of periodic paralyses: hypokalemic periodic paralysis (hypoKPP and hyperkalemic periodic paralysis (hyperKPP, based on changes in serum potassium levels during the attacks, and three distinct forms of myotonias: paramyotonia congenita (PC, potassium-aggravated myotonia (PAM, and myotonia congenita (MC. PC and PAM have been linked to missense mutations in the SCN4A gene, which encodes α subunit of the voltage-gated sodium channel, whereas MC is caused by mutations in the chloride channel gene (CLCN1. Exercise is known to trigger, aggravate, or relieve symptoms. Therefore, exercise can be used as a functional test in electromyography to improve the diagnosis of these muscle disorders. Abnormal changes in the compound muscle action potential can be disclosed using different exercise tests. Five electromyographic (EMG patterns (I-V that may be used in clinical practice as guides for molecular diagnosis are discussed.

  10. Experimental knee pain reduces muscle strength

    DEFF Research Database (Denmark)

    Henriksen, Marius; Mortensen, Sara Rosager; Aaboe, Jens

    2011-01-01

    Pain is the principal symptom in knee pathologies and reduced muscle strength is a common observation among knee patients. However, the relationship between knee joint pain and muscle strength remains to be clarified. This study aimed at investigating the changes in knee muscle strength following...... experimental knee pain in healthy volunteers, and if these changes were associated with the pain intensities. In a crossover study, 18 healthy subjects were tested on 2 different days. Using an isokinetic dynamometer, maximal muscle strength in knee extension and flexion was measured at angular velocities 0....... Knee pain reduced the muscle strength by 5 to 15% compared to the control conditions (P knee extension and flexion at all angular velocities. The reduction in muscle strength was positively correlated to the pain intensity. Experimental knee pain significantly reduced knee extension...

  11. The oculomotor system of decapod cephalopods: eye muscles, eye muscle nerves, and the oculomotor neurons in the central nervous system.

    Science.gov (United States)

    Budelmann, B U; Young, J Z

    1993-04-29

    Fourteen extraocular eye muscles are described in the decapods Loligo and Sepioteuthis, and thirteen in Sepia; they are supplied by four eye muscle nerves. The main action of most of the muscles is a linear movement of the eyeball, only three muscles produce strong rotations. The arrangement, innervation and action of the decapod eye muscles are compared with those of the seven eye muscles and seven eye muscle nerves in Octopus. The extra muscles in decapods are attached to the anterior and superior faces of the eyes. At least, the anterior muscles, and presumably also the superior muscles, are concerned with convergent eye movements for binocular vision during fixation and capture of prey by the tentacles. The remaining muscles are rather similar in the two cephalopod groups. In decapods, the anterior muscles include conjunctive muscles; these cross the midline and each presumably moves both eyes at the same time during fixation. In the squids Loligo and Sepioteuthis there is an additional superior conjunctive muscle of perhaps similar function. Some of the anterior muscles are associated with a narrow moveable plate, the trochlear cartilage; it is attached to the eyeball by trochlear membranes. Centripetal cobalt fillings showed that all four eye muscle nerves have fibres that originate from somata in the ipsilateral anterior lateral pedal lobe, which is the oculomotor centre. The somata of the individual nerves show different but overlapping distributions. Bundles of small presumably afferent fibres were seen in two of the four nerves. They do not enter the anterior lateral pedal lobe but run to the ventral magnocellular lobe; some afferent fibres enter the brachio-palliovisceral connective and run perhaps as far as the palliovisceral lobe.

  12. Muscle contraction and force

    DEFF Research Database (Denmark)

    Brüggemann, Dagmar Adeline; Risbo, Jens; Pierzynowski, Stefan G.

    2008-01-01

    Muscle contraction studies often focus solely on myofibres and the proteins known to be involved in the processes of sarcomere shortening and cross-bridge cycling, but skeletal muscle also comprises a very elaborate ancillary network of capillaries, which not only play a vital role in terms...... of nutrient delivery and waste product removal, but are also tethered to surrounding fibres by collagen "wires". This paper therefore addresses aspects of the ancillary network of skeletal muscle at both a microscopic and functional level in order to better understand its role holistically as a considerable...

  13. Electrically controllable artificial PAN muscles

    Science.gov (United States)

    Salehpoor, Karim; Shahinpoor, Mohsen; Mojarrad, Mehran

    1996-02-01

    Artificial muscles made with polyacrylonitrile (PAN) fibers are traditionally activated in electrolytic solution by changing the pH of the solution by the addition of acids and/or bases. This usually consumes a considerable amount of weak acids or bases. Furthermore, the synthetic muscle (PAN) itself has to be impregnated with an acid or a base and must have an appropriate enclosure or provision for waste collection after actuation. This work introduces a method by which the PAN muscle may be elongated or contracted in an electric field. We believe this is the first time that this has been achieved with PAN fibers as artificial muscles. In this new development the PAN muscle is first put in close contact with one of the two platinum wires (electrodes) immersed in an aqueous solution of sodium chloride. Applying an electric voltage between the two wires changes the local acidity of the solution in the regions close to the platinum wires. This is because of the ionization of sodium chloride molecules and the accumulation of Na+ and Cl- ions at the negative and positive electrode sites, respectively. This ion accumulation, in turn, is accompanied by a sharp increase and decrease of the local acidity in regions close to either of the platinum wires, respectively. An artificial muscle, in close contact with the platinum wire, because of the change in the local acidity will contract or expand depending on the polarity of the electric field. This scheme allows the experimenter to use a fixed flexible container of an electrolytic solution whose local pH can be modulated by an imposed electric field while the produced ions are basically trapped to stay in the neighborhood of a given electrode. This method of artificial muscle activation has several advantages. First, the need to use a large quantity of acidic or alkaline solutions is eliminated. Second, the use of a compact PAN muscular system is facilitated for applications in active musculoskeletal structures. Third, the

  14. Muscle activity characterization by laser Doppler Myography

    Science.gov (United States)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Primo Tomasini, Enrico

    2013-09-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin.

  15. Muscle activity characterization by laser Doppler Myography

    International Nuclear Information System (INIS)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Tomasini, Enrico Primo

    2013-01-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin

  16. Quantitative muscle ultrasonography in amyotrophic lateral sclerosis.

    NARCIS (Netherlands)

    Arts, I.M.P.; Rooij, F.G. van; Overeem, S.; Pillen, S.; Janssen, H.M.; Schelhaas, H.J.; Zwarts, M.J.

    2008-01-01

    In this study, we examined whether quantitative muscle ultrasonography can detect structural muscle changes in early-stage amyotrophic lateral sclerosis (ALS). Bilateral transverse scans were made of five muscles or muscle groups (sternocleidomastoid, biceps brachii/brachialis, forearm flexor group,

  17. Plasticity of the transverse tubules following denervation and subsequent reinnervation in rat slow and fast muscle fibres.

    Science.gov (United States)

    Takekura, Hiroaki; Tamaki, Hiroyuki; Nishizawa, Tomie; Kasuga, Norikatsu

    2003-01-01

    We have studied the effects of short term denervation followed by reinnervation on the ultrastructure of the membrane systems and on the content of and distribution of key proteins involved in calcium regulation of fast-twitch (FT) extensor digitorum longus (EDL) and slow-twitch (ST) soleus (SOL) muscle fibres. Ischiadic nerve freezing resulted in total lack of neuromuscular transmission for 3 days followed by a slow recovery, but no decline in twitch force elicited by direct stimulation. The latter measurements indicate no significant atrophy within this time frame. The membrane systems of skeletal muscle fibres were visualized using Ca92+)-K3Fe(CN)6-OsO4 techniques and observed using a high voltage electron microscope. [3H]nitrendipine binding was used to detect levels of dihydropyridine receptor (DHPR) expression. The Ca2+ pumping free sarcoplasmic reticulum domains were not affected by the denervation, but the Ca2+ release domains were dramatically increased, particularly in the FT-EDL muscle fibres. The increase is evidenced by a doubling up of the areas of contacts between SR and transverse (t-) tubules, so that in place of the normal triadic arrangement, pentadic and heptadic junctions, formed by multiple interacting layers of ST and t-tubules are seen. Frequency of pentads and heptads increases and declines in parallel to the denervation and reinnervation but with a delay. Immunofluorecence and electron microscopy observations show presence of DHPR and ryanodine receptor clusters at pentads and heptads junctions. A significant (P muscle fibres indicating that overexpression of DHPRs accompanies the build up extra junctional contacts. The results indicate that denervation reversibly affects the domains of the membrane systems involved in excitation-contraction coupling.

  18. Increased skeletal muscle 11βHSD1 mRNA is associated with lower muscle strength in ageing.

    Directory of Open Access Journals (Sweden)

    Alixe H M Kilgour

    Full Text Available Sarcopenia, the loss of muscle mass and function with age, is associated with increased morbidity and mortality. Current understanding of the underlying mechanisms is limited. Glucocorticoids (GC in excess cause muscle weakness and atrophy. We hypothesized that GC may contribute to sarcopenia through elevated circulating levels or increased glucocorticoid receptor (GR signaling by increased expression of either GR or the GC-amplifying enzyme 11 beta-hydroxysteroid dehydrogenase type 1 (11βHSD1 in muscle.There were 82 participants; group 1 comprised 33 older men (mean age 70.2 years, SD 4.4 and 19 younger men (22.2 years, 1.7 and group 2 comprised 16 older men (79.1 years, 3.4 and 14 older women (80.1 years, 3.7. We measured muscle strength, mid-thigh cross-sectional area, fasting morning plasma cortisol, quadriceps muscle GR and 11βHSD1 mRNA, and urinary glucocorticoid metabolites. Data were analysed using multiple linear regression adjusting for age, gender and body size.Muscle strength and size were not associated with plasma cortisol, total urinary glucocorticoids or the ratio of urinary 5β-tetrahydrocortisol +5α-tetrahydrocortisol to tetrahydrocortisone (an index of systemic 11βHSD activity. Muscle strength was associated with 11βHSD1 mRNA levels (β -0.35, p = 0.04, but GR mRNA levels were not significantly associated with muscle strength or size.Although circulating levels of GC are not associated with muscle strength or size in either gender, increased cortisol generation within muscle by 11βHSD1 may contribute to loss of muscle strength with age, a key component of sarcopenia. Inhibition of 11βHSD1 may have therapeutic potential in sarcopenia.

  19. Oral dosing of chemical indicators for in vivo monitoring of Ca2+ dynamics in insect muscle.

    Directory of Open Access Journals (Sweden)

    Ferdinandus

    Full Text Available This paper proposes a remarkably facile staining protocol to visually investigate dynamic physiological events in insect tissues. We attempted to monitor Ca2+ dynamics during contraction of electrically stimulated living muscle. Advances in circuit miniaturization and insect neuromuscular physiology have enabled the hybridization of living insects and man-made electronic components, such as microcomputers, the result of which has been often referred as a Living Machine, Biohybrid, or Cyborg Insect. In order for Cyborg Insects to be of practical use, electrical stimulation parameters need to be optimized to induce desired muscle response (motor action and minimize the damage in the muscle due to the electrical stimuli. Staining tissues and organs as well as measuring the dynamics of chemicals of interest in muscle should be conducted to quantitatively and systematically evaluate the effect of various stimulation parameters on the muscle response. However, existing staining processes require invasive surgery and/or arduous procedures using genetically encoded sensors. In this study, we developed a non-invasive and remarkably facile method for staining, in which chemical indicators can be orally administered (oral dosing. A chemical Ca2+ indicator was orally introduced into an insect of interest via food containing the chemical indicator and the indicator diffused from the insect digestion system to the target muscle tissue. We found that there was a positive relationship between the fluorescence intensity of the indicator and the frequency of electrical stimulation which indicates the orally dosed indicator successfully monitored Ca2+ dynamics in the muscle tissue. This oral dosing method has a potential to globally stain tissues including neurons, and investigating various physiological events in insects.

  20. Oral dosing of chemical indicators for in vivo monitoring of Ca2+ dynamics in insect muscle.

    Science.gov (United States)

    Ferdinandus; Arai, Satoshi; Ishiwata, Shin'ichi; Suzuki, Madoka; Sato, Hirotaka

    2015-01-01

    This paper proposes a remarkably facile staining protocol to visually investigate dynamic physiological events in insect tissues. We attempted to monitor Ca2+ dynamics during contraction of electrically stimulated living muscle. Advances in circuit miniaturization and insect neuromuscular physiology have enabled the hybridization of living insects and man-made electronic components, such as microcomputers, the result of which has been often referred as a Living Machine, Biohybrid, or Cyborg Insect. In order for Cyborg Insects to be of practical use, electrical stimulation parameters need to be optimized to induce desired muscle response (motor action) and minimize the damage in the muscle due to the electrical stimuli. Staining tissues and organs as well as measuring the dynamics of chemicals of interest in muscle should be conducted to quantitatively and systematically evaluate the effect of various stimulation parameters on the muscle response. However, existing staining processes require invasive surgery and/or arduous procedures using genetically encoded sensors. In this study, we developed a non-invasive and remarkably facile method for staining, in which chemical indicators can be orally administered (oral dosing). A chemical Ca2+ indicator was orally introduced into an insect of interest via food containing the chemical indicator and the indicator diffused from the insect digestion system to the target muscle tissue. We found that there was a positive relationship between the fluorescence intensity of the indicator and the frequency of electrical stimulation which indicates the orally dosed indicator successfully monitored Ca2+ dynamics in the muscle tissue. This oral dosing method has a potential to globally stain tissues including neurons, and investigating various physiological events in insects.

  1. Relationship between physical exercise, muscle damage and delayed-onset muscle soreness

    Directory of Open Access Journals (Sweden)

    Denis Foschini

    2007-03-01

    Full Text Available The objective of the present study was to investigate the relationship between physical exercise involving muscle damage and delayed-onset muscle soreness (DOMS. A literature review of national and international periodicals was carried out. Muscle structures (membranes, Z-line, sarcomeres, T tubules and myofi brils can become damaged as a result of an imposed mechanical overload. Of greatest note are exercises requiring strength, particularly when muscular action is eccentric. Damage to skeletal musculature can be analyzed by direct methods (muscle biopsy or magnetic resonance or by indirect methods (maximum voluntary movement, subjective pain perception scales, analysis of enzyme and protein concentrations in blood. Creatine kinase (CK, lactate dehydrogenase (LDH, myosin heavy chain fragments, troponin-I and myoglobin can be used as indirect markers of muscle damage. Both DOMS and muscle damage can be infl uenced by the type of activity, with emphasis on eccentric muscle movements, type of exercise, velocity of the movement, interval period between series, the level of individual fi tness, this last primarily affecting beginners. When myotrauma occurs, muscle damage repair is initiated by leukocytes migrating to the injured area, although, the histamines, prostaglandins, kinins and K+ produced by neutrophils and macrophages stimulate free nerve endings in the muscle, causing the DOMS. Despite this apparent relationship between muscle damage and DOMS, it is not possible toestablish a linear relationship between these two variables, since published data are divergent. RESUMO O objetivo desse estudo foi investigar as relações do exercício físico com o dano muscular e dor muscular de início tardio (DMIT. Para tanto, foi realizada uma revisão de literatura de periódicos nacionais e internacionais. O dano muscular pode ocorrer em estruturas musculares (membranas, linha Z, sarcolema, túbulos T e miofi brilas em função da sobrecarga mec

  2. 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...

  3. 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

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

    Science.gov (United States)

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

    2015-07-01

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

  5. A new approach to assess the gastrocnemius muscle volume in rodents using ultrasound; comparison with the gastrocnemius muscle index.

    Directory of Open Access Journals (Sweden)

    Tim H J Nijhuis

    Full Text Available INTRODUCTION: The purpose of this study was to determine the reliability and validity of a new non-invasive ultrasound technique to measure gastrocnemius muscle atrophy after nerve denervation in an animal model. METHODS: In sixteen rodents an eight mm sciatic nerve gap was created. In the following 8 weeks, each week, two rodents were euthanized and the gastrocnemius muscle was examined using two different ultrasound systems and two investigators. The standardized ultrasound measurement protocol consisted of identifying pre-defined anatomical landmarks: 1 the fibula, 2 the fibular nerve, and 3 the junction between the most distal point of the semitendinosus muscle and gastrocnemius muscle. Consequently, we measured the muscle thickness as the length of the line between the fibula and the junction between the two muscles, perpendicular to the fibular nerve. After the ultrasound recording, the muscle mass was determined. RESULTS: A steep decline of muscle weight of 24% was observed after one week. In the following weeks, the weight further decreased and then remained stable from 6 weeks onwards, resulting in a maximal muscle weight decrease of 82%. The correlation coefficient was >0.96 between muscle diameter and weight using both ultrasound systems. The inter-rater reliability was excellent for both devices on the operated side (ICC of 0.99 for both ultrasound systems and good for the non-operated site (ICC's: 0.84 & 0.89. The difference between the muscle mass ratio and the muscle thickness ratio was not more than 5% with two outliers of approximately 13%. DISCUSSION: We have developed an innovative, highly reliable technique for quantifying muscle atrophy after nerve injury. This technique allows serial measurements in the same animal over time. This is a significant advantage compared to the conventional technique for quantifying muscle atrophy, which requires sacrificing the animal.

  6. The expression of HSP in human skeletal muscle. Effects of muscle fiber phenotype and training background

    DEFF Research Database (Denmark)

    Folkesson, Mattias; Mackey, Abigail L; Langberg, Henning

    2013-01-01

    AIM: Exercise-induced adaptations of skeletal muscle are related to training mode and can be muscle fibre type specific. This study aimed to investigate heat shock protein expression in type I and type II muscle fibres in resting skeletal muscle of subjects with different training backgrounds...... myosin heavy chain I and IIA, αB-crystallin, HSP27, HSP60 and HSP70. RESULTS: In ACT and RES, but not in END, a fibre type specific expression with higher staining intensity in type I than type II fibres was seen for αB-crystallin. The opposite (II>I) was found for HSP27 in subjects from ACT (6 of 12...... HSPs in human skeletal muscle is influenced by muscle fibre phenotype. The fibre type specific expression of HSP70 is influenced by resistance and endurance training whereas those of αB-crystallin and HSP27 are influenced only by endurance training suggesting the existence of a training...

  7. Overexpression of SMPX in adult skeletal muscle does not change skeletal muscle fiber type or size.

    Directory of Open Access Journals (Sweden)

    Einar Eftestøl

    Full Text Available Mechanical factors such as stretch are thought to be important in the regulation of muscle phenotype. Small muscle protein X-linked (SMPX is upregulated by stretch in skeletal muscle and has been suggested to serve both as a transcription factor and a mechanosensor, possibly giving rise to changes in both fiber size and fiber type. We have used in vivo confocal imaging to study the subcellular localization of SMPX in skeletal muscle fibers of adult rats using a SMPX-EGFP fusion protein. The fusion protein was localized predominantly in repetitive double stripes flanking the Z-disc, and was excluded from all nuclei. This localization would be consistent with SMPX being a mechanoreceptor, but not with SMPX playing a role as a transcription factor. In vivo overexpression of ectopic SMPX in skeletal muscle of adult mice gave no significant changes in fiber type distribution or cross sectional area, thus a role of SMPX in regulating muscle phenotype remains unclear.

  8. [Asymmetric hypertrophy of the masticatory muscles].

    Science.gov (United States)

    Arzul, L; Corre, P; Khonsari, R H; Mercier, J-M; Piot, B

    2012-06-01

    Hypertrophy of the masticatory muscles most commonly affects the masseter. Less common cases of isolated or associated temporalis hypertrophy are also reported. Parafunctional habits, and more precisely bruxism, can favor the onset of the hypertrophy. This condition is generally idiopathic and can require both medical and/or surgical management. A 29-year-old patient was referred to our department for an asymmetric swelling of the masticatory muscles. Physical examination revealed a bilateral hypertrophy of the masticatory muscles, predominantly affecting the right temporalis and the left masseter. Major bruxism was assessed by premature dental wearing. The additional examinations confirmed the isolated muscle hypertrophy. Benign asymmetric hypertrophy of the masticatory muscles promoted by bruxism was diagnosed. Treatment with injections of type A botulinum toxin was conducted in association with a splint and relaxation. Its effectiveness has been observed at six months. Few cases of unilateral or bilateral temporalis hypertrophy have been reported, added to the more common isolated masseter muscles hypertrophy. The diagnosis requires to rule out secondary hypertrophies and tumors using Magnetic Resonance Imaging. The condition is thought to be favoured by parafunctional habits such as bruxism. The conservative treatment consists in reducing the volume of the masticatory muscles using intramuscular injections of type A botulinum toxin. Other potential conservative treatments are wearing splints and muscle relaxant drugs. Surgical procedures aiming to reduce the muscle volume and/or the bone volume (mandibular gonioplasty) can be proposed. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  9. Jaw muscles in older overdenture patients.

    Science.gov (United States)

    Newton, James P; McManus, Frank C; Menhenick, Stephen

    2004-03-01

    To determine, using computer tomography (CT), whether the retention of a small number of teeth in the older adult used to support overdentures could affect the cross-sectional area (CSA) and X-ray density of two jaw closing muscles. Cross-sectional study of a group of older patients subdivided into dentate, edentulous and those wearing overdentures supported by two to five teeth. The sample consisted of 24 subjects aged 55-68 years. CSA and X-ray density of two jaw closing muscles, masseter and medial pterygoid were measured and evaluated using CT. There were no significant differences between left and right jaw muscles, but the CSA of the masseter muscles were significantly larger than the medial pterygoid muscles. The CSA of the masseter and medial pterygoid muscles was significantly smaller in edentulous subjects compared with dentate subjects but no significant difference was observed between subjects wearing overdentures and those with a natural dentition. No significant differences were observed with the X-ray density between different muscles or dental states. The retention of a small number of teeth in the older adult used to support overdentures appears to sustain the CSA of two jaw closing muscles and therefore could enhance these patients' masticatory ability compared with those who were edentulous.

  10. Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

    Science.gov (United States)

    Ianuzzo, C. D.; Chen, V.

    1977-01-01

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

  11. Reliability of muscle strength assessment in chronic post-stroke hemiparesis: a systematic review and meta-analysis.

    Science.gov (United States)

    Rabelo, Michelle; Nunes, Guilherme S; da Costa Amante, Natália Menezes; de Noronha, Marcos; Fachin-Martins, Emerson

    2016-02-01

    Muscle weakness is the main cause of motor impairment among stroke survivors and is associated with reduced peak muscle torque. To systematically investigate and organize the evidence of the reliability of muscle strength evaluation measures in post-stroke survivors with chronic hemiparesis. Two assessors independently searched four electronic databases in January 2014 (Medline, Scielo, CINAHL, Embase). Inclusion criteria comprised studies on reliability on muscle strength assessment in adult post-stroke patients with chronic hemiparesis. We extracted outcomes from included studies about reliability data, measured by intraclass correlation coefficient (ICC) and/or similar. The meta-analyses were conducted only with isokinetic data. Of 450 articles, eight articles were included for this review. After quality analysis, two studies were considered of high quality. Five different joints were analyzed within the included studies (knee, hip, ankle, shoulder, and elbow). Their reliability results varying from low to very high reliability (ICCs from 0.48 to 0.99). Results of meta-analysis for knee extension varying from high to very high reliability (pooled ICCs from 0.89 to 0.97), for knee flexion varying from high to very high reliability (pooled ICCs from 0.84 to 0.91) and for ankle plantar flexion showed high reliability (pooled ICC = 0.85). Objective muscle strength assessment can be reliably used in lower and upper extremities in post-stroke patients with chronic hemiparesis.

  12. [Molecular mechanisms of skeletal muscle hypertrophy].

    Science.gov (United States)

    Astratenkova, I V; Rogozkin, V A

    2014-06-01

    Enzymes Akt, AMPK, mTOR, S6K and PGC-1a coactivator take part in skeletal muscles in the regulation of synthesis of proteins. The expression of these proteins is regulated by growth factors, hormones, nutrients, mechanical loading and leads to an increase in muscle mass and skeletal muscle hypertrophy. The review presents the results of studies published in the past four years, which expand knowledge on the effects of various factors on protein synthesis in skeletal muscle. The attention is focused on the achievements that reveal and clarify the signaling pathways involved in the regulation of protein synthesis in skeletal muscle. The central place is taken by mTOR enzyme which controls and regulates the main stages of the cascade of reactions of muscle proteins providing synthesis in the conditions of human life. coactivator PGC-1a.

  13. Making muscles "stronger": exercise, nutrition, drugs.

    Science.gov (United States)

    Aagaard, P

    2004-06-01

    As described in this review, maximal muscle strength is strongly influenced by resistive-types of exercise, which induce adaptive changes in both neuromuscular function and muscle morphology. Further, timed intake of protein in conjunction with resistance training elicit greater strength and muscle size gains than resistance training alone. Creatine supplementation amplifies the hypertrophic response to resistance training, although some individuals may not respond positively. Locally produced muscle growth factors are upregulated during creatine supplementation, which contributes to increase the responsiveness of muscle cells to intensive training stimuli. Usage of anabolic steroids boosts muscle hypertrophy beyond inherent genetical limits, not only by increasing the DNA transcription rate for myofibrillar proteins but also by increasing the nucleus-to-cytoplasm ratio due to accelerated activation of myogenic satellite cells. However, severe tissue damaging effects exist with anabolic steroids, some of which are irreversible.

  14. The hamstring muscle complex

    NARCIS (Netherlands)

    van der Made, A. D.; Wieldraaijer, T.; Kerkhoffs, G. M.; Kleipool, R. P.; Engebretsen, L.; van Dijk, C. N.; Golanó, P.

    2015-01-01

    The anatomical appearance of the hamstring muscle complex was studied to provide hypotheses for the hamstring injury pattern and to provide reference values of origin dimensions, muscle length, tendon length, musculotendinous junction (MTJ) length as well as width and length of a tendinous

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  16. Expression of interleukin-15 in human skeletal muscle effect of exercise and muscle fibre type composition

    DEFF Research Database (Denmark)

    Nielsen, Anders Rinnov; Mounier, Remi; Plomgaard, Peter

    2007-01-01

    The cytokine interleukin-15 (IL-15) has been demonstrated to have anabolic effects in cell culture systems. We tested the hypothesis that IL-15 is predominantly expressed by type 2 skeletal muscle fibres, and that resistance exercise regulates IL-15 expression in muscle. Triceps brachii, vastus...... lateralis quadriceps and soleus muscle biopsies were obtained from normally physically active, healthy, young male volunteers (n = 14), because these muscles are characterized by having different fibre-type compositions. In addition, healthy, normally physically active male subjects (n = 8) not involved...

  17. Coexistence of a pectoralis quartus muscle, a supernumerary head of biceps brachii muscle and an accessory head of flexor digitorum profundus muscle.

    Science.gov (United States)

    Song, Halim; Kim, Jinu; Yoon, Sang-Pil

    2018-05-26

    Although anatomical variations in the upper limb are frequent, coexistence of multiple combined variations is rare. During a routine educational dissection at Jeju National University Medical School, three muscular variations were found in a 75-year-old Korean male cadaver, in which a supraclavicular cephalic vein was also found in ipsilateral upper extremity during skinning (Go et al., 2017). Here we describe characteristics of the pectoralis quartus muscle, the supernumerary head of biceps brachii muscle and an accessory head of flexor digitorum profundus muscle, and discuss their coexistence from morphological and embryological points of view.

  18. Mind-muscle connection training principle: influence of muscle strength and training experience during a pushing movement.

    Science.gov (United States)

    Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus D; Sundstrup, Emil; Colado, Juan Carlos; Andersen, Lars L

    2017-07-01

    To investigate the effect of different attentional focus conditions on muscle activity during the push-up exercise and to assess the possible influence of muscle strength and training experience. Eighteen resistance-trained men performed 1RM bench press testing and were familiarized with the procedure during the first session. In the second session, three different conditions were randomly performed: regular push-up and push-up focusing on using the pectoralis major and triceps brachii muscles, respectively. Surface electromyography (EMG) was recorded and analyzed (EMG normalized to max; nEMG) for the triceps brachii and pectoralis major muscles. Participants had on average 8 (SD 6) years of training experience and 1RM of 1.25 (SD 0.28) kg per kg bodyweight. Focusing on using pectoralis major increased activity in this muscle by 9% nEMG (95% CI 5-13; Cohen's d 0.60) compared with the regular condition. Triceps activity was not significantly influenced by triceps focus although borderline significant, with a mean difference of 5% nEMG (95% CI 0-10; Cohen's d 0.30). However, years of training experience was positively associated with the ability to selectively activate the triceps (β = 0.41, P = 0.04), but not the pectoralis. Bench press 1RM was not significantly associated with the ability to selectively activate the muscles. Pectoralis activity can be increased when focusing on using this muscle during push-ups, whereas the ability to do this for the triceps is dependent on years of training experience. Maximal muscle strength does not appear to be a decisive factor for the ability to selectively activate these muscles.

  19. The Emerging Role of Skeletal Muscle Metabolism as a Biological Target and Cellular Regulator of Cancer-Induced Muscle Wasting

    Science.gov (United States)

    Carson, James A.; Hardee, Justin P.; VanderVeen, Brandon N.

    2015-01-01

    While skeletal muscle mass is an established primary outcome related to understanding cancer cachexia mechanisms, considerable gaps exist in our understanding of muscle biochemical and functional properties that have recognized roles in systemic health. Skeletal muscle quality is a classification beyond mass, and is aligned with muscle’s metabolic capacity and substrate utilization flexibility. This supplies an additional role for the mitochondria in cancer-induced muscle wasting. While the historical assessment of mitochondria content and function during cancer-induced muscle loss was closely aligned with energy flux and wasting susceptibility, this understanding has expanded to link mitochondria dysfunction to cellular processes regulating myofiber wasting. The primary objective of this article is to highlight muscle mitochondria and oxidative metabolism as a biological target of cancer cachexia and also as a cellular regulator of cancer-induced muscle wasting. Initially, we examine the role of muscle metabolic phenotype and mitochondria content in cancer-induced wasting susceptibility. We then assess the evidence for cancer-induced regulation of skeletal muscle mitochondrial biogenesis, dynamics, mitophagy, and oxidative stress. In addition, we discuss environments associated with cancer cachexia that can impact the regulation of skeletal muscle oxidative metabolism. The article also examines the role of cytokine-mediated regulation of mitochondria function regulation, followed by the potential role of cancer-induced hypogonadism. Lastly, a role for decreased muscle use in cancer-induced mitochondrial dysfunction is reviewed. PMID:26593326

  20. CD133+ cells derived from skeletal muscles of Duchenne muscular dystrophy patients have a compromised myogenic and muscle regenerative capability.

    Science.gov (United States)

    Meng, Jinhong; Muntoni, Francesco; Morgan, Jennifer

    2018-05-12

    Cell-mediated gene therapy is a possible means to treat muscular dystrophies like Duchenne muscular dystrophy. Autologous patient stem cells can be genetically-corrected and transplanted back into the patient, without causing immunorejection problems. Regenerated muscle fibres derived from these cells will express the missing dystrophin protein, thus improving muscle function. CD133+ cells derived from normal human skeletal muscle contribute to regenerated muscle fibres and form muscle stem cells after their intra-muscular transplantation into an immunodeficient mouse model. But it is not known whether CD133+ cells derived from DMD patient muscles have compromised muscle regenerative function. To test this, we compared CD133+ cells derived from DMD and normal human muscles. DMD CD133+ cells had a reduced capacity to undergo myogenic differentiation in vitro compared with CD133+ cells derived from normal muscle. In contrast to CD133+ cells derived from normal human muscle, those derived from DMD muscle formed no satellite cells and gave rise to significantly fewer muscle fibres of donor origin, after their intra-muscular transplantation into an immunodeficient, non-dystrophic, mouse muscle. DMD CD133+ cells gave rise to more clones of smaller size and more clones that were less myogenic than did CD133+ cells derived from normal muscle. The heterogeneity of the progeny of CD133+ cells, combined with the reduced proliferation and myogenicity of DMD compared to normal CD133+ cells, may explain the reduced regenerative capacity of DMD CD133+ cells. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Muscle satellite cell heterogeneity and self-renewal

    Science.gov (United States)

    Motohashi, Norio; Asakura, Atsushi

    2014-01-01

    Adult skeletal muscle possesses extraordinary regeneration capacities. After muscle injury or exercise, large numbers of newly formed muscle fibers are generated within a week as a result of expansion and differentiation of a self-renewing pool of muscle stem cells termed muscle satellite cells. Normally, satellite cells are mitotically quiescent and reside beneath the basal lamina of muscle fibers. Upon regeneration, satellite cells are activated, and give rise to daughter myogenic precursor cells. After several rounds of proliferation, these myogenic precursor cells contribute to the formation of new muscle fibers. During cell division, a minor population of myogenic precursor cells returns to quiescent satellite cells as a self-renewal process. Currently, accumulating evidence has revealed the essential roles of satellite cells in muscle regeneration and the regulatory mechanisms, while it still remains to be elucidated how satellite cell self-renewal is molecularly regulated and how satellite cells are important in aging and diseased muscle. The number of satellite cells is decreased due to the changing niche during ageing, resulting in attenuation of muscle regeneration capacity. Additionally, in Duchenne muscular dystrophy (DMD) patients, the loss of satellite cell regenerative capacity and decreased satellite cell number due to continuous needs for satellite cells lead to progressive muscle weakness with chronic degeneration. Thus, it is necessary to replenish muscle satellite cells continuously. This review outlines recent findings regarding satellite cell heterogeneity, asymmetric division and molecular mechanisms in satellite cell self-renewal which is crucial for maintenance of satellite cells as a muscle stem cell pool throughout life. In addition, we discuss roles in the stem cell niche for satellite cell maintenance, as well as related cell therapies for approaching treatment of DMD. PMID:25364710

  2. Muscle Satellite Cell Heterogeneity and Self-Renewal

    Directory of Open Access Journals (Sweden)

    Norio eMotohashi

    2014-01-01

    Full Text Available Adult skeletal muscle possesses extraordinary regeneration capacities. After muscle injury or exercise, large numbers of newly formed muscle fibers are generated within a week as a result of expansion and differentiation of a self-renewing pool of muscle stem cells termed muscle satellite cells. Normally, satellite cells are mitotically quiescent and reside beneath the basal lamina of muscle fibers. Upon regeneration, satellite cells are activated, and give rise to daughter myogenic precursor cells. After several rounds of proliferation, these myogenic precursor cells contribute to the formation of new muscle fibers. During cell division, a minor population of myogenic precursor cells returns to quiescent satellite cells as a self-renewal process. Currently, accumulating evidence has revealed the essential roles of satellite cells in muscle regeneration and the regulatory mechanisms, while it still remains to be elucidated how satellite cell self-renewal is molecularly regulated and how satellite cells are important in aging and diseased muscle. The number of satellite cells is decreased due to the changing niche during ageing, resulting in attenuation of muscle regeneration capacity. Additionally, in Duchenne muscular dystrophy (DMD patients, the loss of satellite cell regenerative capacity and decreased satellite cell number due to continuous needs for satellite cells lead to progressive muscle weakness with chronic degeneration. Thus, it is necessary to replenish muscle satellite cells continuously. This review outlines recent findings regarding satellite cell heterogeneity, asymmetric division and molecular mechanisms in satellite cell self-renewal which is crucial for maintenance of satellite cells as a muscle stem cell pool throughout life. In addition, we discuss roles in the stem cell niche for satellite cell maintenance, as well as related cell therapies for approaching treatment of DMD.

  3. Muscle activity pattern dependent pain development and alleviation.

    Science.gov (United States)

    Sjøgaard, Gisela; Søgaard, Karen

    2014-12-01

    Muscle activity is for decades considered to provide health benefits irrespectively of the muscle activity pattern performed and whether it is during e.g. sports, transportation, or occupational work tasks. Accordingly, the international recommendations for public health-promoting physical activity do not distinguish between occupational and leisure time physical activity. However, in this body of literature, attention has not been paid to the extensive documentation on occupational physical activity imposing a risk of impairment of health - in particular musculoskeletal health in terms of muscle pain. Focusing on muscle activity patterns and musculoskeletal health it is pertinent to elucidate the more specific aspects regarding exposure profiles and body regional pain. Static sustained muscle contraction for prolonged periods often occurs in the neck/shoulder area during occupational tasks and may underlie muscle pain development in spite of rather low relative muscle load. Causal mechanisms include a stereotype recruitment of low threshold motor units (activating type 1 muscle fibers) characterized by a lack of temporal as well as spatial variation in recruitment. In contrast during physical activities at leisure and sport the motor recruitment patterns are more dynamic including regularly relatively high muscle forces - also activating type 2 muscles fibers - as well as periods of full relaxation even of the type 1 muscle fibers. Such activity is unrelated to muscle pain development if adequate recovery is granted. However, delayed muscle soreness may develop following intensive eccentric muscle activity (e.g. down-hill skiing) with peak pain levels in thigh muscles 1-2 days after the exercise bout and a total recovery within 1 week. This acute pain profile is in contrast to the chronic muscle pain profile related to repetitive monotonous work tasks. The painful muscles show adverse functional, morphological, hormonal, as well as metabolic characteristics. Of

  4. Muscle-directed gene therapy for phenylketonuria (PKU): Development of transgenic mice with muscle-specific phenylalanine hydroxylase expression

    Energy Technology Data Exchange (ETDEWEB)

    Harding, C.O.; Messing, A.; Wolff, J.A. [Univ. of Wisconsin, Madison, WI (United States)

    1994-09-01

    Phenylketonuria (PKU) is an attractive target for gene therapy because of shortcomings in current therapy including lifelong commitment to a difficult and expensive diet, persistent mild cognitive deficits in some children despite adequate dietary therapy, and maternal PKU syndrome. Phenylalanine hydroxylase (PAH) is normally expressed only in liver, but we propose to treat PKU by introducing the gene for PAH into muscle. In order to evaluate both the safety and efficacy of this approach, we have a developed a trangenic mouse which expresses PAH in both cardiac and skeletal muscle. The transgene includes promoter and enhancer sequences from the mouse muscle creatine kinase (MCK) gene fused to the mouse liver PAH cDNA. Mice which have inherited the transgene are healthy, active, and do not exhibit any signs of muscle weakness or wasting. Ectopic PAH expression in muscle is not detrimental to the health, neurologic function, or reproduction of the mice. Pah{sup enu2} hyperphenylalaninemic mice, a model of human PAH deficiency, bred to carry the transgene have substantial PAH expression in cardiac and skeletal muscle but none in liver. Muscle PAH expression alone does not complement the hyperphenylalaninemic phenotype of Pah{sup enu2} mice. However, administration of reduced tetrahydrobiopterin to transgenic Pah{sup enu2} mice is associated with a 25% mean decrease in serum phenylalanine levels. We predict that ectopic expression of PAH in muscle along with adequate muscle supplies of reduced biopterin cofactor will decrease hyperphenylalaninemia in PKU.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-15

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

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

    International Nuclear Information System (INIS)

    Drakonaki, Eleni E.; Allen, Gina M.

    2010-01-01

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

  7. Morphology of muscle attachment sites in the modern human hand does not reflect muscle architecture.

    Science.gov (United States)

    Williams-Hatala, E M; Hatala, K G; Hiles, S; Rabey, K N

    2016-06-23

    Muscle attachment sites (entheses) on dry bones are regularly used by paleontologists to infer soft tissue anatomy and to reconstruct behaviors of extinct organisms. This method is commonly applied to fossil hominin hand bones to assess their abilities to participate in Paleolithic stone tool behaviors. Little is known, however, about how or even whether muscle anatomy and activity regimes influence the morphologies of their entheses, especially in the hand. Using the opponens muscles from a sample of modern humans, we tested the hypothesis that aspects of hand muscle architecture that are known to be influenced by behavior correlate with the size and shape of their associated entheses. Results show no consistent relationships between these behaviorally-influenced aspects of muscle architecture and entheseal morphology. Consequently, it is likely premature to infer patterns of behavior, such as stone tool making in fossil hominins, from these same entheses.

  8. Muscle Wasting and Resistance of Muscle Anabolism: The “Anabolic Threshold Concept” for Adapted Nutritional Strategies during Sarcopenia

    Directory of Open Access Journals (Sweden)

    Dominique Dardevet

    2012-01-01

    Full Text Available Skeletal muscle loss is observed in several physiopathological situations. Strategies to prevent, slow down, or increase recovery of muscle have already been tested. Besides exercise, nutrition, and more particularly protein nutrition based on increased amino acid, leucine or the quality of protein intake has generated positive acute postprandial effect on muscle protein anabolism. However, on the long term, these nutritional strategies have often failed in improving muscle mass even if given for long periods of time in both humans and rodent models. Muscle mass loss situations have been often correlated to a resistance of muscle protein anabolism to food intake which may be explained by an increase of the anabolic threshold toward the stimulatory effect of amino acids. In this paper, we will emphasize how this anabolic resistance may affect the intensity and the duration of the muscle anabolic response at the postprandial state and how it may explain the negative results obtained on the long term in the prevention of muscle mass. Sarcopenia, the muscle mass loss observed during aging, has been chosen to illustrate this concept but it may be kept in mind that it could be extended to any other catabolic states or recovery situations.

  9. Muscle specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

    DEFF Research Database (Denmark)

    Olesen, Annesofie Thorup; Jensen, Bente Rona; Uhlendorf, Toni L

    2014-01-01

    length, passive stiffness and passive force of spastic GA were decreased whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However......, the extent of this interaction was not different in the spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes seen for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate......The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO) and plantaris (PL) were assessed in anesthetized spastic...

  10. Increased IGF-IEc expression and mechano-growth factor production in intestinal muscle of fibrostenotic Crohn's disease and smooth muscle hypertrophy.

    Science.gov (United States)

    Li, Chao; Vu, Kent; Hazelgrove, Krystina; Kuemmerle, John F

    2015-12-01

    The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-β1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribute to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-β1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of α-smooth muscle actin, γ-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-β1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation. Copyright © 2015 the American Physiological Society.

  11. Muscle Shear Moduli Changes and Frequency of Alternate Muscle Activity of Plantar Flexor Synergists Induced by Prolonged Low-Level Contraction

    Directory of Open Access Journals (Sweden)

    Ryota Akagi

    2017-09-01

    Full Text Available During prolonged low-level contractions, synergist muscles are activated in an alternating pattern of activity and silence called as alternate muscle activity. Resting muscle stiffness is considered to increase due to muscle fatigue. Thus, we investigated whether the difference in the extent of fatigue of each plantar flexor synergist corresponded to the difference in the frequency of alternate muscle activity between the synergists using muscle shear modulus as an index of muscle stiffness. Nineteen young men voluntarily participated in this study. The shear moduli of the resting medial and lateral gastrocnemius muscles (MG and LG and soleus muscle (SOL were measured using shear wave ultrasound elastography before and after a 1-h sustained contraction at 10% peak torque during maximal voluntary contraction of isometric plantar flexion. One subject did not accomplish the task and the alternate muscle activity for MG was not found in 2 subjects; therefore, data for 16 subjects were used for further analyses. The magnitude of muscle activation during the fatiguing task was similar in MG and SOL. The percent change in shear modulus before and after the fatiguing task (MG: 16.7 ± 12.0%, SOL: −4.1 ± 13.9%; mean ± standard deviation and the alternate muscle activity during the fatiguing task (MG: 33 [20–51] times, SOL: 30 [17–36] times; median [25th–75th percentile] were significantly higher in MG than in SOL. The contraction-induced change in shear modulus (7.4 ± 20.3% and the alternate muscle activity (37 [20–45] times of LG with the lowest magnitude of muscle activation during the fatiguing task among the plantar flexors were not significantly different from those of the other muscles. These results suggest that the degree of increase in muscle shear modulus induced by prolonged contraction corresponds to the frequency of alternate muscle activity between MG and SOL during prolonged contraction. Thus, it is likely that, compared with

  12. Hypoxia Aggravates Inactivity-Related Muscle Wasting

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    Tadej Debevec

    2018-05-01

    Full Text Available Poor musculoskeletal state is commonly observed in numerous clinical populations such as chronic obstructive pulmonary disease (COPD and heart failure patients. It, however, remains unresolved whether systemic hypoxemia, typically associated with such clinical conditions, directly contributes to muscle deterioration. We aimed to experimentally elucidate the effects of systemic environmental hypoxia upon inactivity-related muscle wasting. For this purpose, fourteen healthy, male participants underwent three 21-day long interventions in a randomized, cross-over designed manner: (i bed rest in normoxia (NBR; PiO2 = 133.1 ± 0.3 mmHg, (ii bed rest in normobaric hypoxia (HBR; PiO2 = 90.0 ± 0.4 mmHg and ambulatory confinement in normobaric hypoxia (HAmb; PiO2 = 90.0 ± 0.4 mmHg. Peripheral quantitative computed tomography and vastus lateralis muscle biopsies were performed before and after the interventions to obtain thigh and calf muscle cross-sectional areas and muscle fiber phenotype changes, respectively. A significant reduction of thigh muscle size following NBR (-6.9%, SE 0.8%; P < 0.001 was further aggravated following HBR (-9.7%, SE 1.2%; P = 0.027. Bed rest-induced muscle wasting in the calf was, by contrast, not exacerbated by hypoxic conditions (P = 0.47. Reductions in both thigh (-2.7%, SE 1.1%, P = 0.017 and calf (-3.3%, SE 0.7%, P < 0.001 muscle size were noted following HAmb. A significant and comparable increase in type 2× fiber percentage of the vastus lateralis muscle was noted following both bed rest interventions (NBR = +3.1%, SE 2.6%, HBR = +3.9%, SE 2.7%, P < 0.05. Collectively, these data indicate that hypoxia can exacerbate inactivity-related muscle wasting in healthy active participants and moreover suggest that the combination of both, hypoxemia and lack of activity, as seen in COPD patients, might be particularly harmful for muscle tissue.

  13. Efficacy of muscle exercise in patients with muscular dystrophy: a systematic review showing a missed opportunity to improve outcomes.

    Directory of Open Access Journals (Sweden)

    Silvia Gianola

    Full Text Available BACKGROUND: Although muscular dystrophy causes muscle weakness and muscle loss, the role of exercise in the management of this disease remains controversial. OBJECTIVE: The purpose of this systematic review is to evaluate the role of exercise interventions on muscle strength in patients with muscular dystrophy. METHODS: We performed systematic electronic searches in Medline, Embase, Web of Science, Scopus and Pedro as well as a list of reference literature. We included trials assessing muscle exercise in patients with muscular dystrophy. Two reviewers independently abstracted data and appraised risk of bias. RESULTS: We identified five small (two controlled and three randomized clinical trials comprising 242 patients and two ongoing randomized controlled trials. We were able to perform two meta-analyses. We found an absence of evidence for a difference in muscle strength (MD 4.18, 95% CIs - 2.03 to 10.39; p = 0.91 and in endurance (MD -0.53, 95% CIs -1.11 to 0.05; p = 0.26. In both, the direction of effects favored muscle exercise. CONCLUSIONS: The first included trial about the efficacy of muscular exercise was published in 1978. Even though some benefits of muscle exercise were consistently reported across studies, the benefits might be due to the small size of studies and other biases. Detrimental effects are still possible. After several decades of research, doctors cannot give advice and patients are, thus, denied basic information. A multi-center randomized trial investigating the strength of muscles, fatigue, and functional limitations is needed.

  14. Capsaicin-sensitive muscle afferents modulate the monosynaptic reflex in response to muscle ischemia and fatigue in the rat.

    Science.gov (United States)

    Della Torre, G; Brunetti, O; Pettorossi, V E

    2002-01-01

    The role of muscle ischemia and fatigue in modulating the monosynaptic reflex was investigated in decerebrate and spinalized rats. Field potentials and fast motoneuron single units in the lateral gastrocnemious (LG) motor pool were evoked by dorsal root stimulation. Muscle ischemia was induced by occluding the LG vascular supply and muscle fatigue by prolonged tetanic electrical stimulation of the LG motor nerve. Under muscle ischemia the monosynaptic reflex was facilitated since the size of the early and late waves of the field potential and the excitability of the motoneuron units increased. This effect was abolished after L3-L6 dorsal rhizotomy, but it was unaffected after L3-L6 ventral rhizotomy. By contrast, the monosynaptic reflex was inhibited by muscle fatiguing stimulation, and this effect did not fully depend on the integrity of the dorsal root. However, when ischemia was combined with repetitive tetanic muscle stimulation the inhibitory effect of fatigue was significantly enhanced. Both the ischemia and fatigue effects were abolished by capsaicin injected into the LG muscle at a dose that blocked a large number of group III and IV muscle afferents. We concluded that muscle ischemia and fatigue activate different groups of muscle afferents that are both sensitive to capsaicin, but enter the spinal cord through different roots. They are responsible for opposite effects, when given separately: facilitation during ischemia and inhibition during fatigue; however, in combination, ischemia enhances the responsiveness of the afferent fibres to fatigue.

  15. Can Measured Synergy Excitations Accurately Construct Unmeasured Muscle Excitations?

    Science.gov (United States)

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

    2018-01-01

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

  16. Muscle triacylglycerol and hormone-sensitive lipase activity in untrained and trained human muscles

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff; Biba, Taus O; Galbo, Henrik

    2006-01-01

    During exercise, triacylglycerol (TG) is recruited in skeletal muscles. We hypothesized that both muscle hormone-sensitive lipase (HSL) activity and TG recruitment would be higher in trained than in untrained subjects in response to prolonged exercise. Healthy male subjects (26 +/- 1 years, body ...

  17. An animal model for human masseter muscle: histochemical characterization of mouse, rat, rabbit, cat, dog, pig, and cow masseter muscle

    DEFF Research Database (Denmark)

    Tuxen, A; Kirkeby, S

    1990-01-01

    The masseter muscle of several animal species was investigated by use of a histochemical method for the demonstration of acid-stable and alkali-stable myosin adenosine triphosphatase (ATPase). The following subdivisions of fiber types were used: Type I fibers show weak ATPase activity at pH 9...... II and I fibers, with type II predominating. Cow masseter muscle consisted mainly of type I fibers, although some cow masseter muscles contained a very small number of type II fibers. Pig masseter muscle had both type I, II, and IM fibers. One of the characteristics of human masseter muscle is type...... IM fibers, which are rarely seen in muscles other than the masticatory muscles. Therefore, pig masseter muscle might be a suitable animal model for experimental studies, such as an investigation of the distribution and diameter of fiber types in the masticatory muscles before and after orthognathic...

  18. Measurement and Treatment of Passive Muscle Stiffness

    DEFF Research Database (Denmark)

    Kirk, Henrik

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

  19. Redundancy or heterogeneity in the electric activity of the biceps brachii muscle? Added value of PCA-processed multi-channel EMG muscle activation estimates in a parallel-fibered muscle

    NARCIS (Netherlands)

    Staudenmann, D.; Stegeman, D.F.; van Dieen, J.H.

    2013-01-01

    Conventional bipolar EMG provides imprecise muscle activation estimates due to possibly heterogeneous activity within muscles and due to improper alignment of the electrodes with the muscle fibers. Principal component analysis (PCA), applied on multi-channel monopolar EMG yielded substantial

  20. On the origin of muscle synergies: invariant balance in the co-activation of agonist and antagonist muscle pairs

    Directory of Open Access Journals (Sweden)

    Hiroaki eHirai

    2015-11-01

    Full Text Available Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist-antagonist (AA muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, we examined the AA concept using the following explanatory variables: the AA ratio, which is related to the equilibrium-joint angle, and the AA sum, which is associated with joint stiffness. We formulated muscle synergies as a function of AA sums, positing that muscle synergies are composite units of mechanical impedance. The AA concept can be regarded as another form of the equilibrium-point (EP hypothesis, and it can be extended to the concept of EP-based synergies. We introduce here a novel tool for analyzing the neurological and motor functions underlying human movements and review some initial insights from our results about the relationships between muscle synergies, endpoint stiffness, and virtual trajectories (time series of EP. Our results suggest that (1 muscle synergies reflect an invariant balance in the co-activation of AA muscle pairs; (2 each synergy represents the basis for the radial, tangential, and null movements of the virtual trajectory in the polar coordinates centered on the specific joint at the base of the body; and (3 the alteration of muscle synergies (for example, due to spasticity or rigidity following neurological injury results in significant distortion of endpoint stiffness and concomitant virtual trajectories. These results indicate that muscle synergies (i.e., the balance of muscle mechanical impedance are essential for motor control.

  1. On the Origin of Muscle Synergies: Invariant Balance in the Co-activation of Agonist and Antagonist Muscle Pairs.

    Science.gov (United States)

    Hirai, Hiroaki; Miyazaki, Fumio; Naritomi, Hiroaki; Koba, Keitaro; Oku, Takanori; Uno, Kanna; Uemura, Mitsunori; Nishi, Tomoki; Kageyama, Masayuki; Krebs, Hermano Igo

    2015-01-01

    Investigation of neural representation of movement planning has attracted the attention of neuroscientists, as it may reveal the sensorimotor transformation essential to motor control. The analysis of muscle synergies based on the activity of agonist-antagonist (AA) muscle pairs may provide insight into such transformations, especially for a reference frame in the muscle space. In this study, we examined the AA concept using the following explanatory variables: the AA ratio, which is related to the equilibrium-joint angle, and the AA sum, which is associated with joint stiffness. We formulated muscle synergies as a function of AA sums, positing that muscle synergies are composite units of mechanical impedance. The AA concept can be regarded as another form of the equilibrium-point (EP) hypothesis, and it can be extended to the concept of EP-based synergies. We introduce, here, a novel tool for analyzing the neurological and motor functions underlying human movements and review some initial insights from our results about the relationships between muscle synergies, endpoint stiffness, and virtual trajectories (time series of EP). Our results suggest that (1) muscle synergies reflect an invariant balance in the co-activation of AA muscle pairs; (2) each synergy represents the basis for the radial, tangential, and null movements of the virtual trajectory in the polar coordinates centered on the specific joint at the base of the body; and (3) the alteration of muscle synergies (for example, due to spasticity or rigidity following neurological injury) results in significant distortion of endpoint stiffness and concomitant virtual trajectories. These results indicate that muscle synergies (i.e., the balance of muscle mechanical impedance) are essential for motor control.

  2. The muscle protein synthetic response to food ingestion.

    Science.gov (United States)

    Gorissen, Stefan H M; Rémond, Didier; van Loon, Luc J C

    2015-11-01

    Preservation of skeletal muscle mass is of great importance for maintaining both metabolic health and functional capacity. Muscle mass maintenance is regulated by the balance between muscle protein breakdown and synthesis rates. Both muscle protein breakdown and synthesis rates have been shown to be highly responsive to physical activity and food intake. Food intake, and protein ingestion in particular, directly stimulates muscle protein synthesis rates. The postprandial muscle protein synthetic response to feeding is regulated on a number of levels, including dietary protein digestion and amino acid absorption, splanchnic amino acid retention, postprandial insulin release, skeletal muscle tissue perfusion, amino acid uptake by muscle, and intramyocellular signaling. The postprandial muscle protein synthetic response to feeding is blunted in many conditions characterized by skeletal muscle loss, such as aging and muscle disuse. Therefore, it is important to define food characteristics that modulate postprandial muscle protein synthesis. Previous work has shown that the muscle protein synthetic response to feeding can be modulated by changing the amount of protein ingested, the source of dietary protein, as well as the timing of protein consumption. Most of this work has studied the postprandial response to the ingestion of isolated protein sources. Only few studies have investigated the postprandial muscle protein synthetic response to the ingestion of protein dense foods, such as dairy and meat. The current review will focus on the capacity of proteins and protein dense food products to stimulate postprandial muscle protein synthesis and identifies food characteristics that may modulate the anabolic properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Muscle response to leg lengthening during distraction osteogenesis.

    Science.gov (United States)

    Thorey, Fritz; Bruenger, Jens; Windhagen, Henning; Witte, Frank

    2009-04-01

    Continuous lengthening of intact muscles during distraction osteogenesis leads to an increase of sarcomeres and enhances the regeneration of tendons and blood vessels. A high distraction rate leads to an excessive leg and muscle lengthening and might cause damages of muscle fibers with fibrosis, necrosis, and muscle weakness. Complications like muscle contractures or atrophy after postoperative immobilization emphazize the importance of muscles and their function in the clinical outcome. In an animal model of distraction osteogenesis, 18 sheep were operated with an external fixator followed by 4 days latency, 21 days distraction (1.25 mm per day) and 51 days consolidation. The anatomical location (gastrocnemius, peroneus tertius, and first flexor digitorum longus muscle), dimension and occurrence of muscular defects were characterized histologically. The callus formation and leg axis was monitored by weekly X-rays. Additionally, serum creatine kinase was analyzed during a distraction and consolidation period. Significant signs of muscle lesions in all three observed muscles can be found postoperatively, whereas normal callus formation and regular leg axis was observed radiologically. The peroneus tertius and first flexor digitorum longus muscles were found to have significantly more signs of fibrosis, inflammatory, and necrosis. Creatine kinase showed two peaks: 4 and 39 days postoperative as an indication of muscle damage and regeneration. The study implicates that muscle damages should be considered when a long-distance distraction osteogenesis is planned. The surgeon should consider these muscle responses and individually discuss a two-stage treatment or additional muscle tendon releases to minimize the risk of muscle damages.

  4. Role of Smooth Muscle in Intestinal Inflammation

    Directory of Open Access Journals (Sweden)

    Stephen M Collins

    1996-01-01

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

  5. Insulin binding to individual rat skeletal muscles

    International Nuclear Information System (INIS)

    Koerker, D.J.; Sweet, I.R.; Baskin, D.G.

    1990-01-01

    Studies of insulin binding to skeletal muscle, performed using sarcolemmal membrane preparations or whole muscle incubations of mixed muscle or typical red (soleus, psoas) or white [extensor digitorum longus (EDL), gastrocnemius] muscle, have suggested that red muscle binds more insulin than white muscle. We have evaluated this hypothesis using cryostat sections of unfixed tissue to measure insulin binding in a broad range of skeletal muscles; many were of similar fiber-type profiles. Insulin binding per square millimeter of skeletal muscle slice was measured by autoradiography and computer-assisted densitometry. We found a 4.5-fold range in specific insulin tracer binding, with heart and predominantly slow-twitch oxidative muscles (SO) at the high end and the predominantly fast-twitch glycolytic (FG) muscles at the low end of the range. This pattern reflects insulin sensitivity. Evaluation of displacement curves for insulin binding yielded linear Scatchard plots. The dissociation constants varied over a ninefold range (0.26-2.06 nM). Binding capacity varied from 12.2 to 82.7 fmol/mm2. Neither binding parameter was correlated with fiber type or insulin sensitivity; e.g., among three muscles of similar fiber-type profile, the EDL had high numbers of low-affinity binding sites, whereas the quadriceps had low numbers of high-affinity sites. In summary, considerable heterogeneity in insulin binding was found among hindlimb muscles of the rat, which can be attributed to heterogeneity in binding affinities and the numbers of binding sites. It can be concluded that a given fiber type is not uniquely associated with a set of insulin binding parameters that result in high or low binding

  6. Protonation mechanism and location of rate-determining steps for the Ascaris suum nicotinamide adenine dinucleotide-malic enzyme reaction from isotope effects and pH studies

    International Nuclear Information System (INIS)

    Kiick, D.M.; Harris, B.G.; Cook, P.F.

    1986-01-01

    The pH dependence of the kinetic parameters and the primary deuterium isotope effects with nicotinamide adenine dinucleotide (NAD) and also thionicotinamide adenine dinucleotide (thio-NAD) as the nucleotide substrates were determined in order to obtain information about the chemical mechanism and location of rate-determining steps for the Ascaris suum NAD-malic enzyme reaction. The maximum velocity with thio-NAD as the nucleotide is pH-independent from pH 4.2 to 9.6, while with NAD, V decreases below a pK of 4.8. V/K for both nucleotides decreases below a pK of 5.6 and above a pK of 8.9. Both the tartronate pKi and V/Kmalate decrease below a pK of 4.8 and above a pK of 8.9. Oxalate is competitive vs. malate above pH 7 and noncompetitive below pH 7 with NAD as the nucleotide. The oxalate Kis increases from a constant value above a pK of 4.9 to another constant value above a pK of 6.7. The oxalate Kii also increases above a pK of 4.9, and this inhibition is enhanced by NADH. In the presence of thio-NAD the inhibition by oxalate is competitive vs. malate below pH 7. For thio-NAD, both DV and D(V/K) are pH-independent and equal to 1.7. With NAD as the nucleotide, DV decreases to 1.0 below a pK of 4.9, while D(V/KNAD) and D(V/Kmalate) are pH-independent. Above pH 7 the isotope effects on V and the V/K values for NAD and malate are equal to 1.45, the pH-independent value of DV above pH 7. Results indicate that substrates bind to only the correctly protonated form of the enzyme. Two enzyme groups are necessary for binding of substrates and catalysis. Both NAD and malate are released from the Michaelis complex at equal rates which are equal to the rate of NADH release from E-NADH above pH 7. Below pH 7 NADH release becomes more rate-determining as the pH decreases until at pH 4.0 it completely limits the overall rate of the reaction

  7. Muscle Activity Adaptations to Spinal Tissue Creep in the Presence of Muscle Fatigue

    Science.gov (United States)

    Nougarou, François

    2016-01-01

    Aim The aim of this study was to identify adaptations in muscle activity distribution to spinal tissue creep in presence of muscle fatigue. Methods Twenty-three healthy participants performed a fatigue task before and after 30 minutes of passive spinal tissue deformation in flexion. Right and left erector spinae activity was recorded using large-arrays surface electromyography (EMG). To characterize muscle activity distribution, dispersion was used. During the fatigue task, EMG amplitude root mean square (RMS), median frequency and dispersion in x- and y-axis were compared before and after spinal creep. Results Important fatigue-related changes in EMG median frequency were observed during muscle fatigue. Median frequency values showed a significant main creep effect, with lower median frequency values on the left side under the creep condition (p≤0.0001). A significant main creep effect on RMS values was also observed as RMS values were higher after creep deformation on the right side (p = 0.014); a similar tendency, although not significant, was observed on the left side (p = 0.06). A significant creep effects for x-axis dispersion values was observed, with higher dispersion values following the deformation protocol on the left side (p≤0.001). Regarding y-axis dispersion values, a significant creep x fatigue interaction effect was observed on the left side (p = 0.016); a similar tendency, although not significant, was observed on the right side (p = 0.08). Conclusion Combined muscle fatigue and creep deformation of spinal tissues led to changes in muscle activity amplitude, frequency domain and distribution. PMID:26866911

  8. Evaluation of muscle MRI in amyotrophic lateral sclerosis

    International Nuclear Information System (INIS)

    Baba, Yuri; Kuroiwa, Yoshiyuki

    2005-01-01

    Various objective measurements can be used to diagnose amyotrophic lateral sclerosis (ALS). T2-weighted brain MRI images revealed high signal areas at the posterior limb of the internal capsules in ALS patients. Recently, muscle MRI proved useful to evaluate abnormalities of the muscle in myositis patients. Therefore, in the present study, we examined muscle MRI of leg muscles in ALS patients, and correlated MRI with functional measurements, such as muscle strength, and compound muscle action potential amplitude of the tibialis anterior (TA) after stimulation of the peroneal nerve. The subjects consisted of 10 ALS patients (7 males and 3 females), ranging in age from 49 to 87. Neurologic symptoms at the onset of ALS consisted of bulbar dysfunction in one patient, upper extremity involvement in three patients, and lower extremity involvement in six patients. Muscle MRI of the legs was performed in 9 (ALS patients. A peripheral nerve conduction study was performed on the peroneal nerve, with the recording electrode over the TA. The T2-weighted muscle MRI images revealed high signal aeras in the muscle in six ALS patients, whose muscle weakness existed predominantly in the lower extremities. Extracellular fluid accumulation has been proposed to be responsible for the signal increase of denervated muscles on T2-weighted muscle MRI images. We assume that muscle MRI is useful to demonstrate the distribution of muscle involvement in ALS patients and to assess the disease's stage. (author)

  9. Influence on muscle oxygenation to EMG parameters at different skeletal muscle contraction

    Science.gov (United States)

    Zhang, Li; Song, Gaoqing

    2010-02-01

    The purpose of this study is to investigate the influence of muscle oxygenation on EMG parameters during isometric and incremental exercises and to observe the relationship between EMG parameters and muscle oxygenation. Twelve rowers took part in the tests. Near infrared spectrometer was utilized for measurements of muscle oxygenation on lateral quadriceps. sEMG measurement is performed for EMG parameters during isometric and incremental exercises. Results indicated that Oxy-Hb decrease significantly correlated with IEMG, E/T ratio and frequency of impulse signal during 1/3 MVC and 2/3 MVC isometric exercise, and it is also correlated with IEMG, E/T ratio and frequency of impulse signal. Increase of IEMG occurred at the time after Oxy-Hb decrease during incremental exercise and highly correlated with BLa. It is concluded that no matter how heavy the intensity is, Oxy-Hb dissociation may play an important role in affecting EMG parameters of muscle fatigue during isometric exercise. 2) EMG parameters may be influenced by Oxy-Hb dissociation and blood lactate concentration during dynamic exercise.

  10. Muscle fascicle behavior during eccentric cycling and its relation to muscle soreness.

    Science.gov (United States)

    Peñailillo, Luis; Blazevich, Anthony J; Nosaka, Kazunori

    2015-04-01

    A single bout of eccentric exercise confers a protective effect against muscle damage and soreness in subsequent eccentric exercise bouts, but the mechanisms underpinning this effect are unclear. This study compared vastus lateralis (VL) muscle-tendon behavior between two eccentric cycling bouts to test the hypothesis that muscle-tendon behavior would be different between bouts and would be associated with the protective effect. Eleven untrained men (27.1 ± 7.0 yr) performed two bouts of eccentric cycling (ECC1 and ECC2) separated by 2 wk for 10 min at 65% of maximal concentric workload (191.9 ± 44.2 W) each. Muscle soreness (by visual analog scale) and maximal voluntary isometric contraction (MVC) torque of the knee extensors were assessed before and 1-2 d after exercise. Using ultrasonography, VL fascicle length and angle changes during cycling were assessed, and tendinous tissue (TT) length changes were estimated. VL EMG amplitude, crank torque, and knee joint angles were measured during cycling. Soreness was greater (P tendon behavior may be an important mechanism underpinning the protective effect.

  11. In-Vivo Measurement of Muscle Tension: Dynamic Properties of the MC Sensor during Isometric Muscle Contraction

    Directory of Open Access Journals (Sweden)

    Srđan Đorđević

    2014-09-01

    Full Text Available Skeletal muscle is the largest tissue structure in our body and plays an essential role for producing motion through integrated action with bones, tendons, ligaments and joints, for stabilizing body position, for generation of heat through cell respiration and for blood glucose disposal. A key function of skeletal muscle is force generation. Non-invasive and selective measurement of muscle contraction force in the field and in clinical settings has always been challenging. The aim of our work has been to develop a sensor that can overcome these difficulties and therefore enable measurement of muscle force during different contraction conditions. In this study, we tested the mechanical properties of a “Muscle Contraction” (MC sensor during isometric muscle contraction in different length/tension conditions. The MC sensor is attached so that it indents the skin overlying a muscle group and detects varying degrees of tension during muscular contraction. We compared MC sensor readings over the biceps brachii (BB muscle to dynamometric measurements of force of elbow flexion, together with recordings of surface EMG signal of BB during isometric contractions at 15° and 90° of elbow flexion. Statistical correlation between MC signal and force was very high at 15° (r = 0.976 and 90° (r = 0.966 across the complete time domain. Normalized SD or σN = σ/max(FMC was used as a measure of linearity of MC signal and elbow flexion force in dynamic conditions. The average was 8.24% for an elbow angle of 90° and 10.01% for an elbow of angle 15°, which indicates high linearity and good dynamic properties of MC sensor signal when compared to elbow flexion force. The next step of testing MC sensor potential will be to measure tension of muscle-tendon complex in conditions when length and tension change simultaneously during human motion.

  12. Are skeletal muscles independent actuators? Force transmission from soleus muscle in the cat

    NARCIS (Netherlands)

    Maas, H.; Sandercock, T.G.

    2008-01-01

    It is unclear if skeletal muscles act mechanically as independent actuators. The purpose of the present study was to investigate force transmission from soleus (SO) muscle for physiological lengths as well as relative positions in the intact cat hindlimb. We hypothesized that force transmission from

  13. Sex steroids do not affect muscle weight, oxidative metabolism or cytosolic androgen reception binding of functionally overloaded rat Plantaris muscles

    Science.gov (United States)

    Max, S. R.; Rance, N.

    1983-01-01

    The effects of sex steroids on muscle weight and oxidative capacity of rat planaris muscles subjected to functional overload by removal of synergistic muscles were investigated. Ten weeks after bilateral synergist removal, plantaris muscles were significantly hypertrophic compared with unoperated controls. After this period, the ability of the muscles to oxide three substrates of oxidative metabolism was assessed. Experimental procedures are discussed and results are presented herein. Results suggest a lack of beneficial effect of sex hormone status on the process of hypertrophy and on biochemical changes in overloaded muscle. Such findings are not consistent with the idea of synergistic effects of sex steroids and muscle usage.

  14. Extraocular muscle architecture in hawks and owls.

    Science.gov (United States)

    Plochocki, Jeffrey H; Segev, Tamar; Grow, Wade; Hall, Margaret I

    2018-02-06

    A complete and accurate understanding of extraocular muscle function is important to the veterinary care of the avian eye. This is especially true for birds of prey, which rely heavily on vision for survival and yet are prone to ocular injury and disease. To better understand the function of extraocular muscles in birds of prey, we studied extraocular muscle architecture grossly and histologically. This sample was composed of two each of the following species: red-tailed hawk (Buteo jamaicensis), Harris's hawk (Parabuteo unicinctus), great horned owl (Bubo virginianus), and barn owl (Tyto alba). All extraocular muscles were dissected and weighed. To analyze muscle fiber architecture, the superior oblique and quadratus muscles were dissected, weighed, and sectioned at 5 μm thickness in the transverse plane. We calculated the physiologic cross-sectional area and the ratio of muscle mass to predicted effective maximum tetanic tension. Hawk and owl extraocular muscles exhibit significant physiological differences that play roles in ocular movements and closure of the nictitating membrane. Owls, which do not exhibit extraocular movement, have muscle architecture suited to stabilize the position of a massive, tubular eye that protrudes significantly from the orbit. Hawks, which have a more globose eye that is largely contained within the orbit, do not require as much muscular stability and instead have muscle architecture that facilitates rapid eye movement. © 2018 American College of Veterinary Ophthalmologists.

  15. Multi-functional dielectric elastomer artificial muscles for soft and smart machines

    Science.gov (United States)

    Anderson, Iain A.; Gisby, Todd A.; McKay, Thomas G.; O'Brien, Benjamin M.; Calius, Emilio P.

    2012-08-01

    Dielectric elastomer (DE) actuators are popularly referred to as artificial muscles because their impressive actuation strain and speed, low density, compliant nature, and silent operation capture many of the desirable physical properties of muscle. Unlike conventional robots and machines, whose mechanisms and drive systems rapidly become very complex as the number of degrees of freedom increases, groups of DE artificial muscles have the potential to generate rich motions combining many translational and rotational degrees of freedom. These artificial muscle systems can mimic the agonist-antagonist approach found in nature, so that active expansion of one artificial muscle is taken up by passive contraction in the other. They can also vary their stiffness. In addition, they have the ability to produce electricity from movement. But departing from the high stiffness paradigm of electromagnetic motors and gearboxes leads to new control challenges, and for soft machines to be truly dexterous like their biological analogues, they need precise control. Humans control their limbs using sensory feedback from strain sensitive cells embedded in muscle. In DE actuators, deformation is inextricably linked to changes in electrical parameters that include capacitance and resistance, so the state of strain can be inferred by sensing these changes, enabling the closed loop control that is critical for a soft machine. But the increased information processing required for a soft machine can impose a substantial burden on a central controller. The natural solution is to distribute control within the mechanism itself. The octopus arm is an example of a soft actuator with a virtually infinite number of degrees of freedom (DOF). The arm utilizes neural ganglia to process sensory data at the local "arm" level and perform complex tasks. Recent advances in soft electronics such as the piezoresistive dielectric elastomer switch (DES) have the potential to be fully integrated with actuators

  16. Diseases and disorders of muscle.

    Science.gov (United States)

    Pearson, A M; Young, R B

    1993-01-01

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

  17. Regulatory T cells and skeletal muscle regeneration.

    Science.gov (United States)

    Schiaffino, Stefano; Pereira, Marcelo G; Ciciliot, Stefano; Rovere-Querini, Patrizia

    2017-02-01

    Skeletal muscle regeneration results from the activation and differentiation of myogenic stem cells, called satellite cells, located beneath the basal lamina of the muscle fibers. Inflammatory and immune cells have a crucial role in the regeneration process. Acute muscle injury causes an immediate transient wave of neutrophils followed by a more persistent infiltration of M1 (proinflammatory) and M2 (anti-inflammatory/proregenerative) macrophages. New studies show that injured muscle is also infiltrated by a specialized population of regulatory T (Treg) cells, which control both the inflammatory response, by promoting the M1-to-M2 switch, and the activation of satellite cells. Treg cells accumulate in injured muscle in response to specific cytokines, such as IL-33, and promote muscle growth by releasing growth factors, such as amphiregulin. Muscle repair during aging is impaired due to reduced number of Treg cells and can be enhanced by IL-33 supplementation. Migration of Treg cells could also contribute to explain the effect of heterochronic parabiosis, whereby muscle regeneration of aged mice can be improved by a parabiotically linked young partners. In mdx dystrophin-deficient mice, a model of human Duchenne muscular dystrophy, muscle injury, and inflammation is mitigated by expansion of the Treg-cell population but exacerbated by Treg-cell depletion. These findings support the notion that immunological mechanisms are not only essential in the response to pathogenic microbes and tumor cells but also have a wider homeostatic role in tissue repair, and open new perspectives for boosting muscle growth in chronic muscle disease and during aging. © 2016 Federation of European Biochemical Societies.

  18. [Experimental occlusal interference induces the expression of protein gene products and substance P in masseter muscles of rats].

    Science.gov (United States)

    Cao, Ye; Li, Kai; Fu, Kai-yuan; Xie, Qiu-fei

    2010-02-18

    To investigate the peripheral mechanism by studying the histological changes of masseter muscles using HE stains and substance P (SP) and protein gene product 9.5 (PGP9.5) immunohistochemical stains. Fifteen male Sprague-Dawley were randomly assigned into occlusal interference group (n=12) and control group (n=3). In occlusal interference group, 0.4 mm thick crowns were bonded to the rats' first molar of the maxillary. In the control group, rats were anesthetized and mouths were forced open for about 5 min but restorations were not applied. 1, 5, 10, and 21 d after 0.4 mm occlusal alteration treatment, mechanical pain thresholds of bilateral masseter muscles were quantitatively measured by modified electronic anesthesiometer in control group and occlusal interference group. The rats were euthanized by transcardiac perfusion after deep anesthetization at different time points. The paraffin sections of masseter muscles were made and processed for HE, SP, and PGP9.5 immunohistochemical staining. Decreased head withdrawal threshold to mechanical pressure was detected in masseter muscles on both sides following occlusal interference. Histological stains of masseter muscles presented intact following occlusal interference, and no inflammatory cells were observed in both sides. Intensely stained PGP9.5 was observed at 1 d in occlusal interference groups and maintained until the end of the experiment. SP expression was the most obviously increased at 5 d in both sides and gradually decreased to the level of control. Experimental occlusal interference-induced masticatory muscle pain is associated with peripheral sensitization of nociceptive neurons rather than muscle damage and inflammation.

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

    Directory of Open Access Journals (Sweden)

    MB Al-Zghoul

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

  20. Subcellular localization-dependent decrements in skeletal muscle glycogen and mitochondria content following short-term disuse in young and old men

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Suetta, Charlotte; Hvid, Lars G

    2010-01-01

    of disuse and aging on human skeletal muscle glycogen and mitochondria content in subsarcolemmal (SS), intermyofibrillar (IMF), and intramyofibrillar (intra) localizations. Five young (∼23 yr) and five old (∼66 yr) recreationally active men had their quadriceps muscle immobilized for 2 wk by whole leg...... unchanged. A localization-dependent decrease (P = 0.03) in mitochondria content following immobilization was found in both age groups, where SS mitochondria decreased by 33% (P = 0.02), superficial IMF mitochondria decreased by 20% (P = 0.05), and central IMF mitochondria remained unchanged. In conclusion......Previous studies have shown that skeletal muscle glycogen and mitochondria are distributed in distinct subcellular localizations, but the role and regulation of these subcellular localizations are unclear. In the present study, we used transmission electron microscopy to investigate the effect...

  1. Live imaging of muscle histolysis in Drosophila metamorphosis.

    Science.gov (United States)

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

    2016-05-04

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

  2. 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

  3. Cryotherapy induces an increase in muscle stiffness.

    Science.gov (United States)

    Point, M; Guilhem, G; Hug, F; Nordez, A; Frey, A; Lacourpaille, L

    2018-01-01

    Although cold application (ie, cryotherapy) may be useful to treat sports injuries and to prevent muscle damage, it is unclear whether it has adverse effects on muscle mechanical properties. This study aimed to determine the effect of air-pulsed cryotherapy on muscle stiffness estimated using ultrasound shear wave elastography. Myoelectrical activity, ankle passive torque, shear modulus (an index of stiffness), and muscle temperature of the gastrocnemius medialis were measured before, during an air-pulsed cryotherapy (-30°C) treatment of four sets of 4 minutes with 1-minute recovery in between and during a 40 minutes postcryotherapy period. Muscle temperature significantly decreased after the second set of treatment (10 minutes: 32.3±2.5°C; Pcryotherapy induces an increase in muscle stiffness. This acute change in muscle mechanical properties may lower the amount of stretch that the muscle tissue is able to sustain without subsequent injury. This should be considered when using cryotherapy in athletic practice. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Relationship between Muscle Function, Muscle Typology and Postural Performance According to Different Postural Conditions in Young and Older Adults.

    Science.gov (United States)

    Paillard, Thierry

    2017-01-01

    Although motor output of the postural function clearly influences postural performance in young and older subjects, no relationship has been formally established between them. However, the relationship between lower-extremity muscle strength/power and postural performance is often pointed out, especially in older subjects. In fact, the influence of motor output may vary according to the postural condition considered (e.g., static, dynamic, challenging, disturbing). In static postural condition, there may be a relationship between lower-extremity muscle strength and postural performance when the value of muscle strength is below a certain threshold in older subjects. Above this threshold of muscle strength, this relationship may disappear. In dynamic postural condition, lower-extremity muscle power could facilitate compensatory postural actions, limiting induced body imbalance likely to generate falls in older subjects. In young subjects, there could be a relationship between very early rapid torque of the leg extensor muscles and postural performance. In the case of postural reaction to (external) perturbations, a high percentage of type II muscle fibers could be associated with the ability to react quickly to postural perturbations in young subjects, while it may enable a reduction in the risk of falls in older subjects. In practice, in older subjects, muscle strength and/or power training contributes to reducing the risk of falls, as well as slowing down the involution of muscle typology regarding type II muscle fibers.

  5. Muscle and bone follow similar temporal patterns of recovery from muscle-induced disuse due to botulinum toxin injection.

    Science.gov (United States)

    Manske, Sarah L; Boyd, Steven K; Zernicke, Ronald F

    2010-01-01

    If muscle force is a primary source for triggering bone adaptation, with disuse and reloading, bone changes should follow muscle changes. We examined the timing and magnitude of changes in muscle cross-sectional area (MCSA) and bone architecture in response to muscle inactivity following botulinum toxin (BTX) injection. We hypothesized that MCSA would return to baseline levels sooner than bone properties following BTX injection. Female BALB mice (15 weeks old) were injected with 20 muL of BTX (1 U/100 g body mass, n=18) or saline (SAL, n=18) into the posterior calf musculature of one limb. The contralateral limb (CON) served as an internal control. MCSA and bone properties were assessed at baseline, 2, 4, 8, 12, and 16 weeks post-injection using in vivo micro-CT at the tibia proximal metaphysis (bone only) and diaphysis. Muscles were dissected and weighed after sacrifice. Significant GroupxLegxTime interactions indicated that the maximal decrease in MCSA (56%), proximal metaphyseal BV/TV (38%) and proximal diaphyseal Ct.Ar (7%) occurred 4 weeks after injection. There was no delay prior to bone recovery as both muscle and bone properties began to recover after this time, but MCSA and BV/TV remained 15% and 20% lower, respectively, in the BTX-injected leg than the BTX-CON leg 16 weeks post-injection. Gastrocnemius mass (primarily fast-twitch) was 14% lower in the BTX-injected leg than the SAL-injected leg, while soleus mass (primarily slow-twitch) was 15% greater in the BTX group than the SAL group. Our finding that muscle size and bone began to recover at similar times after BTX injection was unexpected. This suggested that partial weight-bearing and/or return of slow-twitch muscle activity in the BTX leg may have been sufficient to stimulate bone recovery. Alternatively, muscle function may have recovered sooner than MCSA. Our results indicated that muscle cross-sectional area, while important, may not be the primary factor associated with bone loss and recovery

  6. 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....

  7. Mediators on human airway smooth muscle.

    Science.gov (United States)

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

    1997-01-01

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

  8. Strenuous exercise aggravates MDMA-induced skeletal muscle damage in mice

    International Nuclear Information System (INIS)

    Duarte, Jose A.; Leao, Anabela; Magalhaes, Jose; Ascensao, Antonio; Bastos, Maria L.; Amado, Francisco L.; Vilarinho, Laura; Quelhas, Dulce; Appell, Hans J.; Carvalho, Felix

    2005-01-01

    The aim of this study was to investigate the influence of ecstasy (MDMA) administration on body temperature and soleus muscle histology in exercised and non-exercised mice. Charles-River mice were distributed into four groups: Control (C), exercise (EX), MDMA treated (M), and M + EX. The treated animals received an i.p. injection (10 mg/kg) of MDMA (saline for C and EX), and the exercise consisted of a 90 min level run at a velocity of 900 m/h, immediately after the MDMA or saline administration. Body temperature was recorded every 30 min via subcutaneous implanted transponder. Animals were sacrificed 1.5, 25.5, and 49.5 h after i.p. injection and the soleus muscles were removed and processed for light and electron microscopy. The MDMA-treated animals showed a significant increase in body temperature (similar in M and M + EX groups), reaching the peak 90 min after i.p. administration; their temperature remained higher than control for more than 5 h. The EX group evidenced a similar and parallel, yet lower temperature increase during exercise and recovery. Morphological signs of damage were rarely encountered in the EX group; they were more pronounced in M group and even aggravated in M + EX group. In conclusion, MDMA and exercise per se increased body temperature but in conjunction did not have a cumulated effect. However, ecstasy and concomitant physical activity might severely accumulate with regard to skeletal muscle toxicity and may lead to rhabdomyolysis

  9. Exercise Promotes Healthy Aging of Skeletal Muscle.

    Science.gov (United States)

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

    2016-06-14

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

  10. Patterns of experimentally induced pain in pericranial muscles

    DEFF Research Database (Denmark)

    Schmidt-Hansen, Peter Thede; Svensson, Peter; Jensen, Troels Staehelin

    2006-01-01

    into the masseter muscle (anova: P pain areas (anova: P cervically innervated muscles had significantly different patterns of spread and referral of pain according to trigeminally vs....... cervically innervated dermatomes (P pain patterns and pain sensitivity in different craniofacial muscles in healthy volunteers, which may be of importance for further research on different craniofacial pain conditions.......Nociceptive mechanisms in the craniofacial muscle tissue are poorly understood. The pain pattern in individual pericranial muscles has not been described before. Experimental muscle pain was induced by standardized infusions of 0.2 ml 1 m hypertonic saline into six craniofacial muscles (masseter...

  11. Skeletal muscle lymphoma: observations at MR imaging

    International Nuclear Information System (INIS)

    Eustace, S.; Winalski, C.S.; McGowen, A.; Lan, H.; Dorfman, D.

    1996-01-01

    We present the MR appearances of three patients with biopsy-proven primary lymphoma of skeletal muscle. In each case lymphoma resulted in bulky expansion of the involved muscle, homogeneously isointense to skeletal muscle on T1-weighted images, homogeneously hyperintense to skeletal muscle on T2-weighted images and diffusely enhancing following intravenous administration of gadopentate dimeglumine. (orig.)

  12. Eccentric Contraction-Induced Muscle Injury: Reproducible, Quantitative, Physiological Models to Impair Skeletal Muscle's Capacity to Generate Force.

    Science.gov (United States)

    Call, Jarrod A; Lowe, Dawn A

    2016-01-01

    In order to investigate the molecular and cellular mechanisms of muscle regeneration an experimental injury model is required. Advantages of eccentric contraction-induced injury are that it is a controllable, reproducible, and physiologically relevant model to cause muscle injury, with injury being defined as a loss of force generating capacity. While eccentric contractions can be incorporated into conscious animal study designs such as downhill treadmill running, electrophysiological approaches to elicit eccentric contractions and examine muscle contractility, for example before and after the injurious eccentric contractions, allows researchers to circumvent common issues in determining muscle function in a conscious animal (e.g., unwillingness to participate). Herein, we describe in vitro and in vivo methods that are reliable, repeatable, and truly maximal because the muscle contractions are evoked in a controlled, quantifiable manner independent of subject motivation. Both methods can be used to initiate eccentric contraction-induced injury and are suitable for monitoring functional muscle regeneration hours to days to weeks post-injury.

  13. Effects of growth hormone on morphology of cardiac muscle and skeletal muscle and hormone levels in rats

    International Nuclear Information System (INIS)

    Yang Ping; Liu Cong; Meng Fanbo; Zhu Jinming; Ni Jinsong; Zhou Hong; Tang Yubo

    2005-01-01

    Objective: To study the effects of growth hormone (GH) on morphology of cardiac muscle and skeletal muscle and hormone levels in Wistar rats. Methods: The GH was given with subcutaneous injection for 15 days, the level of serum GH was determined by radiation-immune method; the body weight and the ratio of organ weight to body weight were determined; the cell appearances of cardiac muscle and skeletal muscle were observed under microscope. the control group was set up. Results; The level of serum GH and rat body weight in experimental group were obviously higher than that in the control group, but the ratio of organ weight to body weight was not obviously different in two groups; musculature hypertrophy and cell nucleolus increasing were observed under microscopy, there were no capillary vessel hyperplasia and inflammatory soakage. Conclusion: GH can induce hypertrophy of cardiac muscle cells and skeletal muscle cells but not interstitial proliferation. (authors)

  14. Skeletal muscle glycogen content and particle size of distinct subcellular localizations in the recovery period after a high-level soccer match

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Krustrup, Peter; Nybo, Lars

    2012-01-01

    Whole muscle glycogen levels remain low for a prolonged period following a soccer match. The present study was conducted to investigate how this relates to glycogen content and particle size in distinct subcellular localizations. Seven high-level male soccer players had a vastus lateralis muscle...... biopsy collected immediately after and 24, 48, 72 and 120 h after a competitive soccer match. Transmission electron microscopy was used to estimate the subcellular distribution of glycogen and individual particle size. During the first day of recovery, glycogen content increased by ~60% in all...

  15. Experimental muscle pain produces central modulation of proprioceptive signals arising from jaw muscle spindles.

    Science.gov (United States)

    Capra, N F; Ro, J Y

    2000-05-01

    The aim of the present study was to investigate the effects of intramuscular injection with hypertonic saline, a well-established experimental model for muscle pain, on central processing of proprioceptive input from jaw muscle spindle afferents. Fifty-seven cells were recorded from the medial edge of the subnucleus interpolaris (Vi) and the adjacent parvicellular reticular formation from 11 adult cats. These cells were characterized as central units receiving jaw muscle spindle input based on their responses to electrical stimulation of the masseter nerve, muscle palpation and jaw stretch. Forty-five cells, which were successfully tested with 5% hypertonic saline, were categorized as either dynamic-static (DS) (n=25) or static (S) (n=20) neurons based on their responses to different speeds and amplitudes of jaw movement. Seventy-six percent of the cells tested with an ipsilateral injection of hypertonic saline showed a significant modulation of mean firing rates (MFRs) during opening and/or holding phases. The most remarkable saline-induced change was a significant reduction of MFR during the hold phase in S units (100%, 18/18 modulated). Sixty-nine percent of the DS units (11/16 modulated) also showed significant changes in MFRs limited to the hold phase. However, in the DS neurons, the MFRs increased in seven units and decreased in four units. Finally, five DS neurons showed significant changes of MFRs during both opening and holding phases. Injections of isotonic saline into the ipsilateral masseter muscle had little effect, but hypertonic saline injections made into the contralateral masseter muscle produced similar results to ipsilateral injections with hypertonic saline. These results unequivocally demonstrate that intramuscular injection with an algesic substance, sufficient to produce muscle pain, produces significant changes in the proprioceptive properties of the jaw movement-related neurons. Potential mechanisms involved in saline-induced changes in the

  16. 38 CFR 4.78 - Muscle function.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Muscle function. 4.78... DISABILITIES Disability Ratings The Organs of Special Sense § 4.78 Muscle function. (a) Examination of muscle function. The examiner must use a Goldmann perimeter chart that identifies the four major quadrants (upward...

  17. Muscle necrosis - computer tomography aspects

    International Nuclear Information System (INIS)

    Franze, I.; Goebel, N.; Stuckmann, G.

    1985-01-01

    In four patients muscle necroses were observed. In two patients these were caused by intraoperative positioning, in one by having worked with a pneumatic hammer and in one possibly by alcohol. CT showed hypodense areas in the affected muscles which were - in the state of subacute necroses - surrounded by hyperaemic borders. The diagnosis was confirmed by puncture or biopsy. After six months hypodense areas were still perceptible in the atrophic muscles of two patients. (orig.) [de

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

    NARCIS (Netherlands)

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

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

  19. Drosophila UNC-45 prevents heat-induced aggregation of skeletal muscle myosin and facilitates refolding of citrate synthase

    Energy Technology Data Exchange (ETDEWEB)

    Melkani, Girish C.; Lee, Chi F.; Cammarato, Anthony [Department of Biology and the Molecular Biology Institute, San Diego State University, San Diego, CA 92182-4614 (United States); Bernstein, Sanford I., E-mail: sbernst@sciences.sdsu.edu [Department of Biology and the Molecular Biology Institute, San Diego State University, San Diego, CA 92182-4614 (United States)

    2010-05-28

    UNC-45 belongs to the UCS (UNC-45, CRO1, She4p) domain protein family, whose members interact with various classes of myosin. Here we provide structural and biochemical evidence that Escherichia coli-expressed Drosophila UNC-45 (DUNC-45) maintains the integrity of several substrates during heat-induced stress in vitro. DUNC-45 displays chaperone function in suppressing aggregation of the muscle myosin heavy meromyosin fragment, the myosin S-1 motor domain, {alpha}-lactalbumin and citrate synthase. Biochemical evidence is supported by electron microscopy, which reveals the first structural evidence that DUNC-45 prevents inter- or intra-molecular aggregates of skeletal muscle heavy meromyosin caused by elevated temperatures. We also demonstrate for the first time that UNC-45 is able to refold a denatured substrate, urea-unfolded citrate synthase. Overall, this in vitro study provides insight into the fate of muscle myosin under stress conditions and suggests that UNC-45 protects and maintains the contractile machinery during in vivo stress.

  20. Recombinant Uncarboxylated Osteocalcin Per Se Enhances Mouse Skeletal Muscle Glucose Uptake in both Extensor Digitorum Longus and Soleus Muscles

    Directory of Open Access Journals (Sweden)

    Xuzhu Lin

    2017-11-01

    Full Text Available Emerging evidence suggests that undercarboxylated osteocalcin (ucOC improves muscle glucose uptake in rodents. However, whether ucOC can directly increase glucose uptake in both glycolytic and oxidative muscles and the possible mechanisms of action still need further exploration. We tested the hypothesis that ucOC per se stimulates muscle glucose uptake via extracellular signal-regulated kinase (ERK, adenosine monophosphate-activated protein kinase (AMPK, and/or the mechanistic target of rapamycin complex 2 (mTORC2-protein kinase B (AKT-AKT substrate of 160 kDa (AS160 signaling cascade. Extensor digitorum longus (EDL and soleus muscles from male C57BL/6 mice were isolated, divided into halves, and then incubated with ucOC with or without the pretreatment of ERK inhibitor U0126. ucOC increased muscle glucose uptake in both EDL and soleus. It also enhanced phosphorylation of ERK2 (Thr202/Tyr204 and AS160 (Thr642 in both muscle types and increased mTOR phosphorylation (Ser2481 in EDL only. ucOC had no significant effect on the phosphorylation of AMPKα (Thr172. The inhibition of ucOC-induced ERK phosphorylation had limited effect on ucOC-stimulated glucose uptake and AS160 phosphorylation in both muscle types, but appeared to inhibit the elevation in AKT phosphorylation only in EDL. Taken together, ucOC at the physiological range directly increased glucose uptake in both EDL and soleus muscles in mouse. The molecular mechanisms behind this ucOC effect on muscle glucose uptake seem to be muscle type-specific, involving enhanced phosphorylation of AS160 but limitedly modulated by ERK phosphorylation. Our study suggests that, since ucOC increases muscle glucose uptake without insulin, it could be considered as a potential agent to improve muscle glucose uptake in insulin resistant conditions.