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Sample records for abductor muscle weakness

  1. Hip abductor weakness is not the cause for iliotibial band syndrome.

    PubMed

    Grau, S; Krauss, I; Maiwald, C; Best, R; Horstmann, T

    2008-07-01

    Muscular deficits in the hip abductors are presumed to be a major factor in the development of Iliotibial Band Syndrome in runners. No definite relationship between muscular weakness of the hip abductors and the development of Iliotibial Band Syndrome or different ratios between hip adduction to abduction have been reported so far. Isokinetic measurements were taken from 10 healthy runners and 10 runners with Iliotibial Band Syndrome. Primary outcome variables were concentric, eccentric, and isometric peak torque of the hip abductors and adductors at 30 degrees/s, and a concentric endurance quotient at the same angle velocity. Differences in muscle strength of the hip abductors between healthy (CO) and injured runners (ITBS) were not statistically significant in any of the muscle functions tested. Both groups showed the same strength differences between hip adduction and abduction, and increased strength in hip adduction. Weakness of hip abductors does not seem to play a role in the etiology of Iliotibial Band Syndrome in runners, since dynamic and static strength measurements did not differ between groups, and differences between hip abduction and adduction were the same. Strengthening of hip abductors seems to have little effect on the prevention of Iliotibial Band Syndrome in runners.

  2. The relationship between hip abductor muscle strength and iliotibial band tightness in individuals with low back pain

    PubMed Central

    2010-01-01

    Background Shortening of the iliotibial band (ITB) has been considered to be associated with low back pain (LBP). It is theorized that ITB tightness in individuals with LBP is a compensatory mechanism following hip abductor muscle weakness. However, no study has clinically examined this theory. The purpose of this study was to investigate the muscle imbalance of hip abductor muscle weakness and ITB tightness in subjects with LBP. Methods A total of 300 subjects with and without LBP between the ages of 20 and 60 participated in this cross-sectional study. Subjects were categorized in three groups: LBP with ITB tightness (n = 100), LBP without ITB tightness (n = 100) and no LBP (n = 100). Hip abductor muscle strength was measured in all subjects. Results Analysis of Covariance (ANCOVA) with the body mass index (BMI) as the covariate revealed significant difference in hip abductor strength between three groups (P < 0.001). Post hoc analysis showed no significant difference in hip abductor muscle strength between the LBP subjects with and without ITB tightness (P = 0.59). However, subjects with no LBP had significantly stronger hip abductor muscle strength compared to subjects with LBP with ITB tightness (P < 0.001) and those with LBP without ITB tightness (P < 0.001). Conclusion The relationship between ITB tightness and hip abductor weakness in patients with LBP is not supported as assumed in theory. More clinical studies are needed to assess the theory of muscle imbalance of hip abductor weakness and ITB tightness in LBP. PMID:20157442

  3. Resisted side-stepping: the effect of posture on hip abductor muscle activation

    PubMed Central

    Berry, Justin W.; Lee, Theresa S.; Foley, Hanna D.; Lewis, Cara L.

    2016-01-01

    Study Design Controlled laboratory study, repeated-measures design. Objectives To compare hip abductor muscle activity and hip and knee joint kinematics in the moving limb to the stance limb during resisted side-stepping and also to determine if muscle activity was affected by the posture (upright standing versus squat) used to perform the exercise. Background Hip abductor weakness has been associated with a variety of lower extremity injuries. Resisted side-stepping is often used as an exercise to increase strength and endurance of the hip abductors. Exercise prescription would benefit from knowing the relative muscle activity level generated in each limb and for different postures during the side-stepping exercise. Methods Twenty-four healthy adults participated in this study. Kinematics and surface electromyographic (EMG) data from the gluteus maximus, gluteus medius, and tensor fascia lata (TFL) were collected as participants performed side-stepping with a resistive band around the ankle while maintaining each of 2 postures: 1) upright standing and 2) squat. Results Mean normalized EMG signal amplitude of the gluteus maximus, gluteus medius, and TFL was higher in the stance limb than the moving limb (P≤.001). Gluteal muscle activity was higher, while TFL muscle activity was lower, in the squat posture compared to the upright standing posture (P<.001). Hip abduction excursion was greater in the stance limb than in the moving limb (P<.001). Conclusions The 3 hip abductor muscles respond differently to the posture variations of side-stepping exercise in healthy individuals. When prescribing resisted side-stepping exercises, therapists should consider the differences in hip abductor activation across limbs and variations in trunk posture. PMID:26161629

  4. Radiographic and ultrasonographic diagnosis of stenosing tenosynovitis of the abductor pollicis longus muscle in dogs.

    PubMed

    Hittmair, Katharina M; Groessl, Veronika; Mayrhofer, Elisabeth

    2012-01-01

    Stenosing tenosynovitis of the abductor pollicis longus muscle causes chronic front limb lameness in dogs. The lesion, similar to de Quervain's tenosynovitis in people, is caused by repetitive movements of the carpus. Thirty dogs with front limb lameness, painful carpal flexion, and a firm soft tissue swelling medial to the carpus were examined prospectively. Seven dogs had bilateral abductor pollicis longus tenosynovitis. Radiographs of the carpus were characterized by a deeper radiolucent medial radial sulcus and bony proliferations medial and slightly cranial to the distal radius, resulting in stenosis of the tendon sheath and subsequent tendinitis. Ultrasonographic examination of the firm soft tissue swelling medial to the carpus was characterized by an irregular hypoechoic abductor pollicis longus tendon or tendinitis in 22 of 37 dogs. Nineteen of 37 abductor pollicis longus tendon sheaths were fluid-filled and all tendon sheaths were thickened, more hyperechoic, with small hyperechoic mineralizations embedded in the connective tissue of the abductor pollicis longus tendon sheath in 25 dogs. Enthesopathy of the abductor pollicis longus tendon was identified in seven dogs. While radiographs of stenosing tenosynovitis of the abductor pollicis longus are helpful in visualizing the deep radial sulcus and osteophytes medial to the distal radius, ultrasonography is useful to distinguish between lesions of the tendon or tendon sheath and to determine thickness and fluid content of the abductor pollicis longus tendon sheath. PMID:22118578

  5. Recurrence of Hypertrophic Abductor Digiti Minimi Muscle of the Foot After Subtotal Resection.

    PubMed

    Schmauss, Daniel; Harder, Yves; Machens, Hans-Guenther; Lohmeyer, Joern Andreas

    2016-01-01

    Soft tissue tumors of the foot are rare, and the diagnosis is often difficult. Surgery is indicated if pain, discomfort, or functional impairment is present or to rule out malignancy. We present the case of a 14-year-old female with a painless swelling at the lateral aspect of her right foot. After radiologic imaging, including ultrasonography and magnetic resonance imaging (MRI), we performed a subtotal resection of the abductor digiti minimi muscle, preserving its motor nerve. Four months later, recurrence of the soft tissue mass was observed. MRI revealed hypertrophy of the small muscles of the foot, including the abductor digiti minimi, quadratus plantae, and flexor digiti minimi brevis. Functional impairment resulted in complete excision of the remnant abductor digiti minimi muscle and partial excision of the flexor digiti minimi brevis muscle another 7 months later. Twelve months after the secondary surgery, neither clinical nor radiologic signs of a second recurrence were found. At the last follow-up visit, the patient was satisfied with the contour of her foot and not hindered at all during sporting activities. Our findings demonstrate that subtotal resection of a bulky muscle, preserving its motor nerve, can result in reactive hypertrophy of the remnant muscle part. The patient must be informed that partial excision of an innervated muscle could result in reactive hypertrophy and must be contrasted with radical muscle excision that might be more likely to result in functional impairment. PMID:25724471

  6. The Influence of Hip Abductor Weakness on Frontal Plane Motion of the Trunk and Pelvis in Patients with Cerebral Palsy

    ERIC Educational Resources Information Center

    Krautwurst, Britta K.; Wolf, Sebastian I.; Heitzmann, Daniel W. W.; Gantz, Simone; Braatz, Frank; Dreher, Thomas

    2013-01-01

    Trendelenburg walking pattern is a common finding in various disorders, including cerebral palsy (CP), where it is seen in children and adults. Clinically, this deviation is viewed as a consequence of hip abductor weakness resulting in pelvic obliquity. Trunk lean to the ipsilateral side is a common compensatory mechanism to counteract pelvic…

  7. Isokinetic imbalance of adductor-abductor hip muscles in professional soccer players with chronic adductor-related groin pain.

    PubMed

    Belhaj, K; Meftah, S; Mahir, L; Lmidmani, F; Elfatimi, A

    2016-11-01

    This study aims to compare the isokinetic profile of hip abductor and adductor muscle groups between soccer players suffering from chronic adductor-related groin pain (ARGP), soccer players without ARGP and healthy volunteers from general population. Study included 36 male professional soccer players, who were randomly selected and followed-up over two years. Of the 21 soccer players eligible to participate in the study, 9 players went on to develop chronic ARGP and 12 players did not. Ten healthy male volunteers were randomly selected from the general population as a control group. Comparison between the abductor and adductor muscle peak torques for players with and without chronic ARGP found a statistically significant difference on the dominant and non-dominant sides (p < .005), with the abductor muscle significantly stronger than the adductor muscle. In the group of healthy volunteers, the adductor muscle groups were significantly stronger than the abductor muscle groups on both dominant and non-dominant sides (p < .05). For the group of players who had developed chronic ARGP, abductor-adductor torque ratios were significantly higher on the affected side (p = .008). The adductor muscle strength was also significantly decreased on the affected side. This imbalance appears to be a risk factor for adductor-related groin injury. Therefore, restoring the correct relationship between these two agonist and antagonist hip muscles may be an important preventative measure that should be a primary concern of training and rehabilitation programmes. PMID:27017973

  8. Assessment of the efficacy of an abductor muscle prosthesis for treatment of laryngeal hemiplegia in horses.

    PubMed

    Speirs, V C; Bourke, J M; Anderson, G A

    1983-10-01

    Four variations of abductor muscle prosthesis for treating laryngeal hemiplegia were evaluated in 153 horses by questionnaire, and in the 100 Thoroughbred racehorses in this group survival analysis was used to compare their racing performances and earnings with those of 400 control horses. The questionnaire indicated that the technique which included a ventriculectomy and 2 prostheses was regarded as being the most successful (P less than 0.01) and resulted in the least residual stertor (P less than 0.001). Survival analysis showed that there was no significant difference between the treated group of horses and the control horses (P greater than 0.05).

  9. Effects of ankle extensor muscle afferent inputs on hip abductor and adductor activity in the decerebrate walking cat.

    PubMed

    Bolton, D A E; Misiaszek, J E

    2012-12-01

    Electrical stimulation of the lateral gastrocnemius-soleus (LGS) nerve at group I afferent strength leads to adaptations in the amplitude and timing of extensor muscle activity during walking in the decerebrate cat. Such afferent feedback in the stance leg might result from a delay in stance onset of the opposite leg. Concomitant adaptations in hip abductor and adductor activity would then be expected to maintain lateral stability and balance until the opposite leg is able to support the body. As many hip abductors and adductors are also hip extensors, we hypothesized that stimulation of the LGS nerve at group I afferent strength would produce increased activation and prolonged burst duration in hip abductor and adductor muscles in the premammillary decerebrate walking cat. LGS nerve stimulation during the extensor phase of the locomotor cycle consistently increased burst amplitude of the gluteus medius and adductor femoris muscles, but not pectineus or gracilis. In addition, LGS stimulation prolonged the burst duration of both gluteus medius and adductor femoris. Unexpectedly, long-duration LGS stimulus trains resulted in two distinct outcomes on the hip abductor and adductor bursting pattern: 1) a change of burst duration and timing similar to medial gastrocnemius; or 2) to continue rhythmically bursting uninterrupted. These results indicate that activation of muscle afferents from ankle extensors contributes to the regulation of activity of some hip abductor and adductor muscles, but not all. These results have implications for understanding the neural control of stability during locomotion, as well as the organization of spinal locomotor networks. PMID:22972967

  10. Correlative analysis of MRI-evident abductor hip muscle degeneration and power after minimally invasive versus conventional unilateral cementless THA.

    PubMed

    Vasilakis, Ioannis; Solomou, Ekaterini; Vitsas, Vasilis; Fennema, Peter; Korovessis, Panagiotis; Siamblis, Dimitrios K

    2012-12-01

    The 2 main null hypotheses of this study were: (1) the 4-year surgical trauma-related degeneration within the hip abductor muscles after a minimally invasive approach to total hip arthroplasty would be similar to that following a conventional approach; and (2) no differences in perioperative blood loss or postoperative hip pain would be observed between the minimally invasive and conventional approaches.In 40 consecutive randomly selected adult patients with unilateral primary hip osteoarthritis, a cementless Zweymüller-Plus THA (Smith & Nephew Orthopaedics, Baar, Switzerland) was implanted by a single surgeon in 1 institution during the same period. Twenty patients underwent a minimally invasive approach (group A), and 20 patients underwent a conventional anterolateral approach (group B). Four years postoperatively, the operated and contralateral nonoperated hips of 37 available patients from both groups were examined with magnetic resonance imaging to show any changes in the gluteus medius and tensor fascia latae. Simultaneously, hip abductor power was measured bilaterally in both groups. Anthropometric data, blood loss, Short Form 36 self-assessment questionnaire, visual analog pain score, and walking distance were also analyzed.The reliability of magnetic resonance imaging and hip abductor power measurements was high. No difference was found in hip abductor power on the operated side between the 2 groups, whereas hip abductor power on the nonoperated side was significantly higher in both groups. This study revealed no mechanical and functional benefits in favor of patients undergoing minimally invasive vs conventional total hip arthroplasty. PMID:23218622

  11. Correlative analysis of MRI-evident abductor hip muscle degeneration and power after minimally invasive versus conventional unilateral cementless THA.

    PubMed

    Vasilakis, Ioannis; Solomou, Ekaterini; Vitsas, Vasilis; Fennema, Peter; Korovessis, Panagiotis; Siamblis, Dimitrios K

    2012-12-01

    The 2 main null hypotheses of this study were: (1) the 4-year surgical trauma-related degeneration within the hip abductor muscles after a minimally invasive approach to total hip arthroplasty would be similar to that following a conventional approach; and (2) no differences in perioperative blood loss or postoperative hip pain would be observed between the minimally invasive and conventional approaches.In 40 consecutive randomly selected adult patients with unilateral primary hip osteoarthritis, a cementless Zweymüller-Plus THA (Smith & Nephew Orthopaedics, Baar, Switzerland) was implanted by a single surgeon in 1 institution during the same period. Twenty patients underwent a minimally invasive approach (group A), and 20 patients underwent a conventional anterolateral approach (group B). Four years postoperatively, the operated and contralateral nonoperated hips of 37 available patients from both groups were examined with magnetic resonance imaging to show any changes in the gluteus medius and tensor fascia latae. Simultaneously, hip abductor power was measured bilaterally in both groups. Anthropometric data, blood loss, Short Form 36 self-assessment questionnaire, visual analog pain score, and walking distance were also analyzed.The reliability of magnetic resonance imaging and hip abductor power measurements was high. No difference was found in hip abductor power on the operated side between the 2 groups, whereas hip abductor power on the nonoperated side was significantly higher in both groups. This study revealed no mechanical and functional benefits in favor of patients undergoing minimally invasive vs conventional total hip arthroplasty.

  12. The effect of hip abductor exercise on muscle strength and trunk stability after an injury of the lower extremities

    PubMed Central

    Kak, Hwang-Bo; Park, Sun-Ja; Park, Byun-Joon

    2016-01-01

    [Purpose] The gluteus medius, a hip abductor, controls femoral movement and stabilizes the pelvis during lower extremity mobilization. [Subjects] This study enrolled 24 subjects into control and experimental groups. [Methods] This randomized controlled study included patients who underwent arthroscopy after meniscus injury and started a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into the experimental gluteus medius resistance exercise group (n=12) and the control group (n=12). The study investigated muscle strength and balance of the flexors, extensors, and abductors of the knee for 8 weeks. [Results] Strengths of knee extensors in patients who underwent rehabilitative exercise for 8 weeks were measured. Strength of the knee extensors of the experimental and control groups increased by 40% and 31%, respectively; strength of the hip flexors of the experimental and control groups increased by 31% and 18%, respectively. Strength of the hip joint muscles showed a 40% increase in the experimental group and a 14% increase in the control group. However, there was a significant difference (18%) in muscle strength of the hip abductors between the groups. Measurements of trunk lateral flexion showed a difference within a group, but no intergroup difference was found. [Conclusion] This study investigated the effect of hip abductor exercise on muscular strength and trunk stability in patients with a meniscus injury. PMID:27134387

  13. The effect of hip abductor exercise on muscle strength and trunk stability after an injury of the lower extremities.

    PubMed

    Kak, Hwang-Bo; Park, Sun-Ja; Park, Byun-Joon

    2016-03-01

    [Purpose] The gluteus medius, a hip abductor, controls femoral movement and stabilizes the pelvis during lower extremity mobilization. [Subjects] This study enrolled 24 subjects into control and experimental groups. [Methods] This randomized controlled study included patients who underwent arthroscopy after meniscus injury and started a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into the experimental gluteus medius resistance exercise group (n=12) and the control group (n=12). The study investigated muscle strength and balance of the flexors, extensors, and abductors of the knee for 8 weeks. [Results] Strengths of knee extensors in patients who underwent rehabilitative exercise for 8 weeks were measured. Strength of the knee extensors of the experimental and control groups increased by 40% and 31%, respectively; strength of the hip flexors of the experimental and control groups increased by 31% and 18%, respectively. Strength of the hip joint muscles showed a 40% increase in the experimental group and a 14% increase in the control group. However, there was a significant difference (18%) in muscle strength of the hip abductors between the groups. Measurements of trunk lateral flexion showed a difference within a group, but no intergroup difference was found. [Conclusion] This study investigated the effect of hip abductor exercise on muscular strength and trunk stability in patients with a meniscus injury.

  14. Effects of hip abductor muscle fatigue on gait control and hip position sense in healthy older adults.

    PubMed

    Arvin, Mina; Hoozemans, Marco J M; Burger, Bart J; Rispens, Sietse M; Verschueren, Sabine M P; van Dieën, Jaap H; Pijnappels, Mirjam

    2015-10-01

    We experimentally investigated whether unilateral hip abductor muscle fatigue affected gait control and hip position sense in older adults. Hip abductor muscles were fatigued unilaterally in side-lying position in 17 healthy older adults (mean age 73.2 SD 7.7 years). Hip joint position sense was assessed by an active-active repositioning test while standing and was expressed as absolute and relative errors. Participants walked on a treadmill at their preferred walking speed, while 3D linear accelerations were collected by an inertial sensor at the lower back. Gait parameters, including step and stride time, local divergence exponents and harmonic ratio were quantified. In fatigued gait, stride time variability and step-to-step asymmetry in the frontal plane were significantly increased. Also a significantly slower mediolateral trunk movement in fatigued leg late stance toward the non-fatigued leg was observed. Despite these temporal and symmetry changes, gait stability in terms of the local divergence exponents was not affected by fatigue. Hip position sense was also affected by fatigue, as indicated by an increased relative error of 0.7° (SD 0.08) toward abduction. In conclusion, negative effects of fatigue on gait variability, step-to-step symmetry, mediolateral trunk velocity control and hip position sense indicate the importance of hip abductor muscles for gait control.

  15. Effect of experimentally reduced distal sensation on postural response to hip abductor/ankle evertor muscle vibration.

    PubMed

    Glasser, S; Collings, R; Paton, J; Marsden, J

    2015-07-01

    This study assessed whether postural responses induced by vibratory perturbations of the hip abductors and ankle evertors, were modified when distal tactile sensation was experimentally reduced through cooling. Sixteen healthy subjects were investigated pre and post cooling. Subjects stood with their eyes closed with a stance width of 4 cm. A 2s vibratory stimulus was applied to the left or right hip abductor or ankle evertor muscle. The order of the site and side of the stimulation was randomised. The postural response to hip abductor and ankle evertor vibration was recorded using 3D motion analysis (Codamotion, Leicestershire). Medio-lateral centre of pressure motion was simultaneously recorded during quiet standing via a force plate (Kistler, UK). Pre-cooling people responded to unilateral ankle vibration with an ipsilateral translation and tilt of the pelvis, and an ipsilateral tilt of the trunk. People responded to unilateral hip vibration with a contralateral translation and tilt of the pelvis, and an ipsilateral tilt of the trunk. Following an experimental reduction in distal tactile sensation there was a significant reduction in the amplitude of pelvic tilt in response to ankle vibration (F(6.2)=P<0.05) and a significant increase in amplitude of pelvic tilt in response to hip vibration (F(5.2)=P<0.05). This suggests that the sensitivity to artificial stimulation of hip proprioception increases with distal cooling, possibly indicating a change in the gain/weighting placed upon sensory information from the hips.

  16. The effects of gluteus maximus and abductor hallucis strengthening exercises for four weeks on navicular drop and lower extremity muscle activity during gait with flatfoot

    PubMed Central

    Goo, Young-Mi; Kim, Tae-Ho; Lim, Jin-Yong

    2016-01-01

    [Purpose] The purpose of the present study is to examine the effects of abductor hallucis and gluteus maximus strengthening exercises on pronated feet. [Subjects and Methods] The present study was conducted with 18 adults without no history of surgery on the foot or ankle. One group performed both gluteus maximus strengthening exercises and abductor hallucis strengthening exercises, while the other group performed only abductor hallucis strengthening exercises five times per week for four weeks. [Results] The group that performed both gluteus maximus and abductor hallucis strengthening exercises showed smaller values in the height of navicular drop than the group that performed only abductor hallucis strengthening exercises. The muscle activity of the gluteus maximus and the vastus medialis increased during heel-strike in the group that added gluteus maximus exercises, and the muscle activity of the abductor hallucis significantly increased in both groups. [Conclusion] Given the results of the present study, it can be suggested that strengthening the gluteus maximus while also performing exercises to correct the pronated foot is an effective method for achieving normal gait. PMID:27134383

  17. Skeletal muscle weakness in osteogeneis imperfecta mice

    PubMed Central

    Gentry, Bettina A; Ferreira, J. Andries; McCambridge, Amanda J.; Brown, Marybeth; Phillips, Charlotte L.

    2010-01-01

    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 (Po, Po/mg and Po/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased Po and an inability to sustain Po 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. PMID:20619344

  18. A rare anomaly of abductor digiti minimi.

    PubMed

    Sañudo, J R; Mirapeix, R M; Ferreira, B

    1993-06-01

    Two cases with anomalous fascicles in abductor digiti minimi, noted in the course of dissecting 62 adult postmortem forearms, are described. Both fascicles arose from the flexor retinaculum and the antebrachial fascia; one was inserted into abductor digiti minimi and the other on the proximal phalanx of the 5th finger. The anomalous muscles crossed the ulnar nerve and in 1 case also the median nerve. In the 2nd case the palmar nerve to the 5th finger was seen to penetrate the anomalous muscle. The ontogeny, morphology and clinical significance of this anomaly are discussed in relation to previously described anomalies of the hypothenar muscles.

  19. Lesion of the hip abductor mechanism

    PubMed Central

    Caviglia, Horacio; Cambiaggi, Guillermo; Vattani, Nosrat; Landro, María Eulalia; Galatro, Gustavo

    2016-01-01

    Introduction: The disruption of the abductor muscles of the hip after hip revision surgery often causes limping, pain, and instability of the implant. The purpose of our paper is to describe a mesh technique to repair hip abductor mechanism injuries after hip revision. Patients and methods: Forty-six patients with hip abductor damage after prosthetic revision were treated. Inclusion criteria were: patients presenting with prosthetic loosening, complaint of pain, and with a positive Trendelenburg sign due to deficient abductor muscle mechanisms. Thirty-one were women (67.39%) with an average age of 64 years (34–82 years). The number of previous revision surgeries was three (two to seven). The Merle d’Aubigné score and variants before and after treatment were also reported. Results: In the postoperative follow-up after hip revision with the mesh technique, the Merle d’Aubigné score improved and the Trendelenburg sign was negative in 78.3% of the patients (p < 0.001). Also, the Trendelenburg test with the knee flexed was negative in 60.9% (p < 0.001) and the stair-climbing test was negative in 60.9% of cases (p < 0.001). The gluteus medius test in the lateral position was negative in 52.2% of patients, and in the lateral position with the knee flexed it was negative in 47.8% of patients (p < 0.001). Discussion: Repair of the abductor mechanism with the mesh technique has proven effective for both partial and total lesions. PMID:27382925

  20. Psychometric Testing of the Gordon Facial Muscle Weakness Assessment Tool

    ERIC Educational Resources Information Center

    Gordon, Shirley C.; Blum, Cynthia Ann; Parcells, Dax Andrew

    2010-01-01

    School nurses may be the first health professionals to assess the onset of facial paralysis/muscle weakness in school-age children. The purpose of this study was to test the psychometric properties of the Gordon Facial Muscle Weakness Assessment Tool (GFMWT) developed by Gordon. Data were collected in two phases. In Phase 1, 4 content experts…

  1. Distribution of muscle weakness of central and peripheral origin.

    PubMed

    Thijs, R D; Notermans, N C; Wokke, J H; van der Graaf, Y; van Gijn, J

    1998-11-01

    According to the established clinical tradition about the distribution of weakness, the ratios of flexor/extensor strength of patients with upper motor neuron lesions are expected to be relatively high for the elbow and wrist and low for the knee. To assess the diagnostic value of these patterns of weakness, muscle strength of 70 patients with limb weakness of central or peripheral origin was measured with a hand held dynamometer. The ratios of flexor/extensor strength at the knee, elbow, and wrist did not differ significantly between patients with central or peripheral origin of muscle weakness. The examination of tendon jerks proved to be of more value as a localising feature. The traditional notion about the distribution of weakness in upper motor neuron lesions may be explained by an intrinsically greater strength in antigravity muscles, together with the effects of hypertonia. PMID:9810962

  2. Objective Evaluation of Muscle Strength in Infants with Hypotonia and Muscle Weakness

    ERIC Educational Resources Information Center

    Reus, Linda; van Vlimmeren, Leo A.; Staal, J. Bart; Janssen, Anjo J. W. M.; Otten, Barto J.; Pelzer, Ben J.; Nijhuis-van der Sanden, Maria W. G.

    2013-01-01

    The clinical evaluation of an infant with motor delay, muscle weakness, and/or hypotonia would improve considerably if muscle strength could be measured objectively and normal reference values were available. The authors developed a method to measure muscle strength in infants and tested 81 typically developing infants, 6-36 months of age, and 17…

  3. Muscle weakness during aging: a deficiency state involving declining angiogenesis.

    PubMed

    Ambrose, Charles

    2015-09-01

    This essay begins by proposing that muscle weakness of old age from sarcopenia is due in large part to reduced capillary density in the muscles, as documented in 9 reports of aged persons and animals. Capillary density (CD) is determined by local levels of various angiogenic factors, which also decline in muscles with aging, as reported in 7 studies of old persons and animals. There are also numerous reports of reduced CD in the aged brain and other studies showing reduced CD in the kidney and heart of aged animals. Thus a waning angiogenesis throughout the body may be a natural occurrence in later years and may account significantly for the lesser ailments (physical and cognitive) of elderly people. Old age is regarded here as a deficiency state which may be corrected by therapeutic angiogenesis, much as a hormonal deficiency can be relieved by the appropriate hormone therapy. Such therapy could employ recombinant angiogenic factors which are now commercially available. PMID:26093038

  4. Peroneal muscle weakness in female basketballers following chronic ankle sprain.

    PubMed

    Rottigni, S A; Hopper, D

    1991-01-01

    Female A-grade basketballers were examined for invertor and evertor muscle strength. Two test groups participated. The injured group were players who had persisting disability following ankle sprains. The control group were players who had never sustained an ankle sprain. Test apparatus was the Orthotron isokinetic dynamometer at contraction speed of 180° per second. Trends towards higher invertor and evertor strength in uninjured group when compared with the injured group found in the present study have been supported by one other report. Invertors were found to be significantly stronger than evertors in both injured and uninjured groups, with the exception of the dominant leg of the uninjured group. A significant weakness in non-dominant evertors of the uninjured group was detected. Dominance did not significantly alter strength differences in the invertor or evertor muscle groups within the uninjured population. The clinical importance of strengthening the peroneal muscles in ankle sprain rehabilitation is discussed, and further research considerations provided.

  5. The abductor and adductor strength characteristics of professional baseball pitcherse.

    PubMed

    Wilk, K E; Andrews, J R; Arrigo, C A

    1995-01-01

    The purpose of this investigation was to establish a data base regarding the isokinetic muscular performance characteristics of the abductor and adductor muscles of professional baseball pitchers. Eighty-three healthy professional baseball pitchers (mean age, 22.6 years; mean weight, 199 pounds) were evaluated by use of a Biodex isokinetic dynamometer. Isokinetic tests were performed concentrically at 180 and 300 deg/sec for both the throwing and nonthrowing shoulders. The testing protocol and test repetitions were standardized for each subject. Statistical analysis was performed using a paired t-test. Determination of the correlation coefficient was made at the P < 0.05 level of significance. Test results for bilateral comparisons of mean peak torque for the throwing and nonthrowing shoulders demonstrated a significant difference in adductor values between the dominant and nondominant shoulders at both test speeds. There were no significant differences between extremities for the shoulder abductor muscles. The abductor-to-adductor muscle ratios between the throwing and nonthrowing shoulders were also statistically significant at both test speeds. Throwing arm values were 82.5% at 180 deg/sec and 93.8% at 300 deg/sec compared with only 66.0% and 70.3%, respectively, for the nonthrowing shoulders.

  6. The effect of isokinetic testing speed on the reliability of muscle fatigue indicators during a hip abductor-adductor fatigue protocol.

    PubMed

    Gautrey, C N; Watson, T; Mitchell, A

    2013-07-01

    The aim of this study was to investigate the reliability of fatigue indicators calculated from peak torque and total work during isokinetic speeds of 60, 90, 120 and 180° · s-1 during a hip fatigue protocol. 10 males suffering from a history of unilateral functional ankle instability and 10 male healthy controls performed 5 maximal concentric contractions on an isokinetic dynamometer. Following a 4 min rest period subjects were instructed to perform repeated maximal concentric contractions to fatigue, which was defined as 3 consecutive repetitions below 50% of the maximum peak torque value. Each testing speed was randomised with 24 h between speeds. The subjects were asked to return to the laboratory 7 days later to repeat the 4 speeds, with 24 h between speeds. Muscle fatigue was determined for each testing speed by the fatigue index, the percent decrease in performance and the slope of the regression equation. The most reliable fatigue determination method was the slope of the regression equation, when testing at a speed of 120° · s-1. It is recommended that future investigators examine and plot their data before choosing the slope of the regression equation as their fatigue indicator, as a linear model is required. PMID:23549692

  7. Cancer-associated muscle weakness: What's bone got to do with it?

    PubMed Central

    Waning, David L; Guise, Theresa A

    2015-01-01

    Cancer-associated muscle weakness is an important paraneoplastic syndrome for which there is currently no treatment. Tumor cells commonly metastasize to bone in advanced cancer to disrupt normal bone remodeling and result in morbidity that includes muscle weakness. Tumor in bone stimulates excessive osteoclast activity, which causes the release of growth factors stored in the mineralized bone matrix. These factors fuel a feed-forward vicious cycle of tumor growth in bone and bone destruction. Recent evidence indicates that these bone-derived growth factors can act systemically to cause muscle weakness. Muscle weakness can be caused by reduced muscle mass or reduced muscle function; in advanced disease, it is likely due to a combination of both reduced quantity and quality of muscle. In this review, we discuss possible mechanisms that lead to skeletal muscle weakness due to bone metastases. PMID:25992285

  8. Early exercise rehabilitation of muscle weakness in acute respiratory failure patients.

    PubMed

    Berry, Michael J; Morris, Peter E

    2013-10-01

    Acute respiratory failure patients experience significant muscle weakness, which contributes to prolonged hospitalization and functional impairments after hospital discharge. Based on our previous work, we hypothesize that an exercise intervention initiated early in the intensive care unit aimed at improving skeletal muscle strength could decrease hospital stay and attenuate the deconditioning and skeletal muscle weakness experienced by these patients.

  9. Abductor Reconstruction with Gluteus Maximus Transfer in Primary Abductor Deficiency during Total Hip Arthroplasty

    PubMed Central

    Jang, Se Ang; Byun, Young Soo; Gu, Tae Hoe

    2016-01-01

    Abductor deficiency in native hip joint may cause severe limping and pain. It is more serious situation in case of arthroplasty due to instability and recurrent dislocation. Well-known causes of abductor deficiency are repeated surgery, chronic trochanteric bursitis, superior gluteal nerve injury, failure of repair of abductor tendon insertion to the greater trochanter. Author had experienced primary abductor deficiency during total hip replacement and treated successfully with the transfer of gluteus maximus. We'd like to introduce the operation technique with the review of literature. PMID:27777922

  10. Distribution and severity of weakness among patients with polymyositis, dermatomyositis and juvenile dermatomyositis

    PubMed Central

    Harris-Love, M. O.; Shrader, J. A.; Koziol, D.; Pahlajani, N.; Jain, M.; Smith, M.; Cintas, H. L.; McGarvey, C. L.; James-Newton, L.; Pokrovnichka, A.; Moini, B.; Cabalar, I.; Lovell, D. J.; Wesley, R.; Plotz, P. H.; Miller, F. W.; Hicks, J. E.

    2009-01-01

    Objective. To describe the distribution and severity of muscle weakness using manual muscle testing (MMT) in 172 patients with PM, DM and juvenile DM (JDM). The secondary objectives included characterizing individual muscle group weakness and determining associations of weakness with functional status and myositis characteristics in this large cohort of patients with myositis. Methods. Strength was assessed for 13 muscle groups using the 10-point MMT and expressed as a total score, subscores based on functional and anatomical regions, and grades for individual muscle groups. Patient characteristics and secondary outcomes, such as clinical course, muscle enzymes, corticosteroid dosage and functional status were evaluated for association with strength using univariate and multivariate analyses. Results. A gradient of proximal weakness was seen, with PM weakest, DM intermediate and JDM strongest among the three myositis clinical groups (P ≤ 0.05). Hip flexors, hip extensors, hip abductors, neck flexors and shoulder abductors were the muscle groups with the greatest weakness among all three clinical groups. Muscle groups were affected symmetrically. Conclusions. Axial and proximal muscle impairment was reflected in the five weakest muscles shared by our cohort of myositis patients. However, differences in the pattern of weakness were observed among all three clinical groups. Our findings suggest a greater severity of proximal weakness in PM in comparison with DM. PMID:19074186

  11. Muscle Weakness Thresholds for Prediction of Diabetes in Adults

    PubMed Central

    Peterson, Mark D.; Zhang, Peng; Choksi, Palak; Markides, Kyriakos S.; Al Snih, Soham

    2016-01-01

    Background Despite the known links between weakness and early mortality, what remains to be fully understood is the extent to which strength preservation is associated with protection from cardiometabolic diseases such as diabetes. Purpose The purposes of this study were to determine the association between muscle strength and diabetes among adults, and to identify age- and sex-specific thresholds of low strength for detection of risk. Methods A population-representative sample of 4,066 individuals, aged 20–85 years, was included from the combined 2011–2012 National Health and Nutrition Examination Survey datasets. Strength was assessed using a hand-held dynamometer, and the single largest reading from either hand was normalized to body mass. A logistic regression model was used to assess the association between normalized grip strength and risk of diabetes, as determined by hemoglobin A1c (HbA1c) levels (≥6.5% [≥48 mmol/mol]), while controlling for sociodemographic characteristics, anthropometric measures, and television viewing time. Results For every 0.05 decrement in normalized strength, there was a 1.26 times increased adjusted odds for diabetes in men and women. Women were at lower odds of having diabetes (OR: 0.49; 95% CI: 0.29–0.82), whereas age, waist circumference and lower income were inversely associated. Optimal sex- and age-specific weakness thresholds to detect diabetes were 0.56, 0.50, and 0.45 for men, and 0.42, 0.38, and 0.33 for women, for ages 20–39 years, 40–59 years, and 60–80 years. Conclusions and Clinical Relevance We present thresholds of strength that can be incorporated into a clinical setting for identifying adults that are at risk for developing diabetes, and that might benefit from lifestyle interventions to reduce risk. PMID:26744337

  12. Acquired Muscle Weakness in the Surgical Intensive Care Unit: Nosology, Epidemiology, Diagnosis, and Prevention.

    PubMed

    Farhan, Hassan; Moreno-Duarte, Ingrid; Latronico, Nicola; Zafonte, Ross; Eikermann, Matthias

    2016-01-01

    Muscle weakness is common in the surgical intensive care unit (ICU). Low muscle mass at ICU admission is a significant predictor of adverse outcomes. The consequences of ICU-acquired muscle weakness depend on the underlying mechanism. Temporary drug-induced weakness when properly managed may not affect outcome. Severe perioperative acquired weakness that is associated with adverse outcomes (prolonged mechanical ventilation, increases in ICU length of stay, and mortality) occurs with persistent (time frame: days) activation of protein degradation pathways, decreases in the drive to the skeletal muscle, and impaired muscular homeostasis. ICU-acquired muscle weakness can be prevented by early treatment of the underlying disease, goal-directed therapy, restrictive use of immobilizing medications, optimal nutrition, activating ventilatory modes, early rehabilitation, and preventive drug therapy. In this article, the authors review the nosology, epidemiology, diagnosis, and prevention of ICU-acquired weakness in surgical ICU patients. PMID:26445385

  13. Acquired Muscle Weakness in the Surgical Intensive Care Unit: Nosology, Epidemiology, Diagnosis, and Prevention.

    PubMed

    Farhan, Hassan; Moreno-Duarte, Ingrid; Latronico, Nicola; Zafonte, Ross; Eikermann, Matthias

    2016-01-01

    Muscle weakness is common in the surgical intensive care unit (ICU). Low muscle mass at ICU admission is a significant predictor of adverse outcomes. The consequences of ICU-acquired muscle weakness depend on the underlying mechanism. Temporary drug-induced weakness when properly managed may not affect outcome. Severe perioperative acquired weakness that is associated with adverse outcomes (prolonged mechanical ventilation, increases in ICU length of stay, and mortality) occurs with persistent (time frame: days) activation of protein degradation pathways, decreases in the drive to the skeletal muscle, and impaired muscular homeostasis. ICU-acquired muscle weakness can be prevented by early treatment of the underlying disease, goal-directed therapy, restrictive use of immobilizing medications, optimal nutrition, activating ventilatory modes, early rehabilitation, and preventive drug therapy. In this article, the authors review the nosology, epidemiology, diagnosis, and prevention of ICU-acquired weakness in surgical ICU patients.

  14. The molecular basis of skeletal muscle weakness in a mouse model of inflammatory myopathy

    PubMed Central

    Coley, William; Rayavarapu, Sree; Pandey, Gouri S.; Sabina, Richard L.; vander Meulen, Jack H.; Ampong, Beryl; Wortmann, Robert L.; Rawat, Rashmi; Nagaraju, Kanneboyina

    2012-01-01

    OBJECTIVE It is generally believed that muscle weakness in patients with polymyositis and dermatomyositis is due to autoimmune and inflammatory processes. However, it has been observed that there is a poor correlation between the suppression of inflammation and a recovery of muscle function in patients. We have therefore hypothesized that non-immune mechanisms also contribute to muscle weakness. In particular, it has been suggested that an acquired deficiency of AMP deaminase (AMPD1) may be responsible for muscle weakness in myositis. METHODS We have used comprehensive functional, behavioral, histological, molecular, enzymatic and metabolic assessments before and after the onset of inflammation in MHC class I mouse model of autoimmune inflammatory myositis. RESULTS We found that muscle weakness and metabolic disturbances were detectable in the mice prior to the appearance of infiltrating mononuclear cells. Force contraction analysis of muscle function revealed that weakness was correlated with AMDP1 expression and was myositis-specific. We also demonstrated that decreasing AMPD1 expression results in decreased muscle strength in healthy mice. Fiber typing suggested that fast-twitch muscles are converted to slow-twitch muscles as myositis progresses, and microarray results indicated that AMPD1 and other purine nucleotide pathway genes are suppressed, along with genes essential to glycolysis. CONCLUSION These data suggest that an AMPD1 deficiency is acquired prior to overt muscle inflammation and is responsible, at least in part, for the muscle weakness that occurs in the mouse model of myositis. AMPD1 is therefore a potential therapeutic target in myositis. PMID:22806328

  15. Clinical strategies for addressing muscle weakness following knee injury.

    PubMed

    Pietrosimone, Brian; Blackburn, J Troy; Harkey, Matthew S; Luc, Brittney A; Pamukoff, Derek N; Hart, Joe M

    2015-04-01

    Muscle strength is a determinate of physical function and increasing muscle strength is an important clinical goal for patients with knee injury. This article discusses the emerging evidence regarding a novel rehabilitation strategy that uses disinhibitory modalities to increase neuromuscular activation in conjunction with traditional muscle strengthening for the purpose of maximizing strength gains following acute knee injury or surgery and in patients with knee osteoarthritis. The use of disinhibitory modalities and specific types of neuromuscular training for clinically maximizing strength are discussed.

  16. Progressive Muscle Atrophy and Weakness After Treatment by Mantle Field Radiotherapy in Hodgkin Lymphoma Survivors

    SciTech Connect

    Leeuwen-Segarceanu, Elena M. van; Dorresteijn, Lucille D.A.; Pillen, Sigrid; Biesma, Douwe H.; Vogels, Oscar J.M.; Alfen, Nens van

    2012-02-01

    Purpose: To describe the damage to the muscles and propose a pathophysiologic mechanism for muscle atrophy and weakness after mantle field radiotherapy in Hodgkin lymphoma (HL) survivors. Methods and Materials: We examined 12 patients treated by mantle field radiotherapy between 1969 and 1998. Besides evaluation of their symptoms, the following tests were performed: dynamometry; ultrasound of the sternocleidomastoid, biceps, and antebrachial flexor muscles; and needle electromyography of the neck, deltoid, and ultrasonographically affected arm muscles. Results: Ten patients (83%) experienced neck complaints, mostly pain and muscle weakness. On clinical examination, neck flexors were more often affected than neck extensors. On ultrasound, the sternocleidomastoid was severely atrophic in 8 patients, but abnormal echo intensity was seen in only 3 patients. Electromyography of the neck muscles showed mostly myogenic changes, whereas the deltoid, biceps, and antebrachial flexor muscles seemed to have mostly neurogenic damage. Conclusions: Many patients previously treated by mantle field radiotherapy develop severe atrophy and weakness of the neck muscles. Neck muscles within the radiation field show mostly myogenic damage, and muscles outside the mantle field show mostly neurogenic damage. The discrepancy between echo intensity and atrophy suggests that muscle damage is most likely caused by an extrinsic factor such as progressive microvascular fibrosis. This is also presumed to cause damage to nerves within the radiated field, resulting in neurogenic damage of the deltoid and arm muscles.

  17. A Curious Case of Proximal Muscle Weakness with Eosinophilic Polymyositis

    PubMed Central

    DeLima, Marianne; Shah, Jaimin; Aung, Win

    2016-01-01

    Eosinophilic polymyositis (EPM) is part of a rare disorder, eosinophilic myopathies (EM), which is a form of polymyositis characterized by the presence of eosinophils in muscle biopsy sections and occasionally blood eosinophilia. Herein, we are presenting an interesting case of eosinophilic polymyositis presenting with muscle pain with no other organ systems involved. PMID:27703830

  18. Impaired mitochondrial respiration and decreased fatigue resistance followed by severe muscle weakness in skeletal muscle of mitochondrial DNA mutator mice.

    PubMed

    Yamada, Takashi; Ivarsson, Niklas; Hernández, Andrés; Fahlström, Andreas; Cheng, Arthur J; Zhang, Shi-Jin; Bruton, Joseph D; Ulfhake, Brun; Westerblad, Håkan

    2012-12-01

    Mitochondrial dysfunction can drastically impair muscle function, with weakness and exercise intolerance as key symptoms. Here we examine the time course of development of muscle dysfunction in a mouse model of premature ageing induced by defective proofreading function of mitochondrial DNA (mtDNA) polymerase (mtDNA mutator mouse). Isolated fast-twitch muscles and single muscle fibres from young (3-5 months) and end-stage (11 months) mtDNA mutator mice were compared to age-matched control mice. Force and free myoplasmic [Ca(2+)] ([Ca(2+)](i)) were measured under resting conditions and during fatigue induced by repeated tetani. Muscles of young mtDNA mutator mice displayed no weakness in the rested state, but had lower force and [Ca(2+)](i) than control mice during induction of fatigue. Muscles of young mtDNA mutator mice showed decreased activities of citrate synthase and β-hydroxyacyl-coenzyme A dehydrogenase, reduced expression of cytochrome c oxidase, and decreased expression of triggers of mitochondrial biogenesis (PGC-1α, PPARα, AMPK). Muscles from end-stage mtDNA mutator mice showed weakness under resting conditions with markedly decreased tetanic [Ca(2+)](i), force per cross-sectional area and protein expression of the sarcoplasmic reticulum Ca(2+) pump (SERCA1). In conclusion, fast-twitch muscles of prematurely ageing mtDNA mutator mice display a sequence of deleterious mitochondrial-to-nucleus signalling with an initial decrease in oxidative capacity, which was not counteracted by activation of signalling to increase mitochondrial biogenesis. This was followed by severe muscle weakness in the end stage. These results have implication for normal ageing and suggest that decreased mitochondrial oxidative capacity due to a sedentary lifestyle may predispose towards muscle weakness developing later in life.

  19. In the idiopathic inflammatory myopathies (IIM), do reactive oxygen species (ROS) contribute to muscle weakness?

    PubMed

    Lightfoot, Adam P; McArdle, Anne; Jackson, Malcolm J; Cooper, Robert G

    2015-07-01

    The idiopathic inflammatory myopathies (IIMs) are a group of rare autoimmune disorders, collectively known as myositis. Affected patients present with proximal muscle weakness, which usually improves following treatment with immunosuppressants, but often incompletely so, thus many patients remain weak. IIMs are characterised histologically by inflammatory cell infiltrates into skeletal muscle and overexpression of major histocompatibility complex I on muscle cell surfaces. Although inflammatory cell infiltrates represent a major feature of myositis there is growing evidence that muscle weakness correlates only poorly with the degree of cellular infiltration, while weakness may in fact precede such infiltrations. The mechanisms underpinning such non-immune cell mediated weakness in IIM are poorly understood. Activation of the endoplasmic reticulum stress pathways appears to be a potential contributor. Data from non-muscle cells indicate that endoplasmic reticulum stress results in altered redox homeostasis capable of causing oxidative damage. In myopathological situations other than IIM, as seen in ageing and sepsis, evidence supports an important role for reactive oxygen species (ROS). Modified ROS generation is associated with mitochondrial dysfunction, depressed force generation and activation of muscle catabolic and autophagy pathways. Despite the growing evidence demonstrating a key role for ROS in skeletal muscle dysfunction in myopathologies other than IIM, no research has yet investigated the role of modified generation of ROS in inducing the weakness characteristic of IIM. This article reviews current knowledge regarding muscle weakness in the absence of immune cells in IIM, and provides a background to the potential role of modified ROS generation as a mechanism of muscle dysfunction. The authors suggest that ROS-mediated mechanisms are potentially involved in non-immune cell mediated weakness seen in IIM and outline how these mechanisms might be

  20. How human gait responds to muscle impairment in total knee arthroplasty patients: Muscular compensations and articular perturbations.

    PubMed

    Ardestani, Marzieh M; Moazen, Mehran

    2016-06-14

    Post-surgical muscle weakness is prevalent among patients who undergo total knee arthroplasty (TKA). We conducted a probabilistic multi-body dynamics (MBD) to determine whether and to what extent habitual gait patterns of TKA patients may accommodate strength deficits in lower extremity muscles. We analyzed muscular and articular compensations in response to various muscle impairments, and the minimum muscle strength requirements needed to preserve TKA gait patterns in its habitual status. Muscle weakness was simulated by reducing the strength parameter of muscle models in MBD analysis. Using impaired models, muscle and joint forces were calculated and compared versus those from baseline gait i.e. TKA habitual gait before simulating muscle weakness. Comparisons were conducted using a relatively new statistical approach for the evaluation of gait waveforms, i.e. Spatial Parameter Mapping (SPM). Principal component analysis was then conducted on the MBD results to quantify the sensitivity of every joint force component to individual muscle impairment. The results of this study contain clinically important, although preliminary, suggestions. Our findings suggested that: (1) hip flexor and ankle plantar flexor muscles compensated for hip extensor weakness; (2) hip extensor, hip adductor and ankle plantar flexor muscles compensated for hip flexor weakness; (3) hip and knee flexor muscles responded to hip abductor weakness; (4) knee flexor and hip abductor balanced hip adductor impairment; and (5) knee extensor and knee flexor weakness were compensated by hip extensor and hip flexor muscles. Future clinical studies are required to validate the results of this computational study. PMID:27063251

  1. Practical Recommendations for Diagnosis and Management of Respiratory Muscle Weakness in Late-Onset Pompe Disease

    PubMed Central

    Boentert, Matthias; Prigent, Hélène; Várdi, Katalin; Jones, Harrison N.; Mellies, Uwe; Simonds, Anita K.; Wenninger, Stephan; Barrot Cortés, Emilia; Confalonieri, Marco

    2016-01-01

    Pompe disease is an autosomal-recessive lysosomal storage disorder characterized by progressive myopathy with proximal muscle weakness, respiratory muscle dysfunction, and cardiomyopathy (in infants only). In patients with juvenile or adult disease onset, respiratory muscle weakness may decline more rapidly than overall neurological disability. Sleep-disordered breathing, daytime hypercapnia, and the need for nocturnal ventilation eventually evolve in most patients. Additionally, respiratory muscle weakness leads to decreased cough and impaired airway clearance, increasing the risk of acute respiratory illness. Progressive respiratory muscle weakness is a major cause of morbidity and mortality in late-onset Pompe disease even if enzyme replacement therapy has been established. Practical knowledge of how to detect, monitor and manage respiratory muscle involvement is crucial for optimal patient care. A multidisciplinary approach combining the expertise of neurologists, pulmonologists, and intensive care specialists is needed. Based on the authors’ own experience in over 200 patients, this article conveys expert recommendations for the diagnosis and management of respiratory muscle weakness and its sequelae in late-onset Pompe disease. PMID:27763517

  2. Understanding compensatory strategies for muscle weakness during gait by simulating activation deficits seen post-stroke.

    PubMed

    Knarr, Brian A; Reisman, Darcy S; Binder-Macleod, Stuart A; Higginson, Jill S

    2013-06-01

    Musculoskeletal simulations have been used to explore compensatory strategies, but have focused on responses to simulated atrophy in a single muscle or muscle group. In a population such as stroke, however, impairments are seen in muscle activation across multiple muscle groups. The objective of this study was to identify available compensatory strategies for muscle weakness during gait by simulating activation deficits in multiple muscle groups. Three dimensional dynamics simulations were created from 10 healthy subjects (48.8 ± 13.3 years, self-selected speed 1.28 ± 0.17 m/s) and constraints were set on the activation capacity of the plantar flexor, dorsiflexor, and hamstrings muscle groups to simulate activation impairme nts seen post-stroke. When the muscle groups are impaired individually, the model requires that the plantar flexor, dorsiflexor, and hamstrings muscle groups are activated to at least 55%, 64%, and 18%, respectively, to recreate the subjects' normal gait pattern. The models were unable to recreate the normal gait pattern with simultaneous impairment of all three muscle groups. Other muscle groups are unable to assist the dorsiflexor muscles during early swing, which suggests that rehabilitation or assistive devices may be required to correct foot drop. By identifying how muscles can interact, clinicians may be able to develop specific strategies for using gait retraining and orthotic assistance to best address an individual's needs.

  3. Excess TGF-β mediates muscle weakness associated with bone metastases in mice

    PubMed Central

    Reiken, Steven; Xie, Wenjun; Andersson, Daniel C.; John, Sutha; Chiechi, Antonella; Wright, Laura E.; Umanskaya, Alisa; Niewolna, Maria; Trivedi, Trupti; Charkhzarrin, Sahba; Khatiwada, Pooja; Wronska, Anetta; Haynes, Ashley; Benassi, Maria Serena; Witzmann, Frank A.; Zhen, Gehua; Wang, Xiao; Cao, Xu; Roodman, G. David; Marks, Andrew R.; Guise, Theresa A.

    2015-01-01

    Cancer-associated muscle weakness is poorly understood and there is no effective treatment. Here, we find that seven different mouse models of human osteolytic bone metastases, representing breast, lung and prostate cancers, as well as multiple myeloma exhibited impaired muscle function, implicating a role for the tumor-bone microenvironment in cancer-associated muscle weakness. We found that TGF-β, released from the bone surface as a result of metastasis-induced bone destruction upregulated NADPH oxidase 4 (Nox4), resulting in elevated oxidization of skeletal muscle proteins, including the ryanodine receptor/calcium (Ca2+) release channel (RyR1). The oxidized RyR1 channels leaked Ca2+, resulting in lower intracellular signaling required for proper muscle contraction. We found that inhibiting RyR1 leak, TGF-β signaling, TGF-β release from bone or Nox4 all improved muscle function in mice with MDA-MB-231 bone metastases. Humans with breast cancer- or lung cancer-associated bone metastases also had oxidized skeletal muscle RyR1 that is not seen in normal muscle. Similarly, skeletal muscle weakness, higher levels of Nox4 protein and Nox4 binding to RyR1, and oxidation of RyR1 were present in a mouse model of Camurati-Engelmann disease, a non-malignant metabolic bone disorder associated with increased TGF-β activity. Thus, metastasis-induced TGF-β release from bone contributes to muscle weakness by decreasing Ca2+-induced muscle force production. PMID:26457758

  4. Excess TGF-β mediates muscle weakness associated with bone metastases in mice.

    PubMed

    Waning, David L; Mohammad, Khalid S; Reiken, Steven; Xie, Wenjun; Andersson, Daniel C; John, Sutha; Chiechi, Antonella; Wright, Laura E; Umanskaya, Alisa; Niewolna, Maria; Trivedi, Trupti; Charkhzarrin, Sahba; Khatiwada, Pooja; Wronska, Anetta; Haynes, Ashley; Benassi, Maria Serena; Witzmann, Frank A; Zhen, Gehua; Wang, Xiao; Cao, Xu; Roodman, G David; Marks, Andrew R; Guise, Theresa A

    2015-11-01

    Cancer-associated muscle weakness is a poorly understood phenomenon, and there is no effective treatment. Here we find that seven different mouse models of human osteolytic bone metastases-representing breast, lung and prostate cancers, as well as multiple myeloma-exhibited impaired muscle function, implicating a role for the tumor-bone microenvironment in cancer-associated muscle weakness. We found that transforming growth factor (TGF)-β, released from the bone surface as a result of metastasis-induced bone destruction, upregulated NADPH oxidase 4 (Nox4), resulting in elevated oxidization of skeletal muscle proteins, including the ryanodine receptor and calcium (Ca(2+)) release channel (RyR1). The oxidized RyR1 channels leaked Ca(2+), resulting in lower intracellular signaling, which is required for proper muscle contraction. We found that inhibiting RyR1 leakage, TGF-β signaling, TGF-β release from bone or Nox4 activity improved muscle function in mice with MDA-MB-231 bone metastases. Humans with breast- or lung cancer-associated bone metastases also had oxidized skeletal muscle RyR1 that is not seen in normal muscle. Similarly, skeletal muscle weakness, increased Nox4 binding to RyR1 and oxidation of RyR1 were present in a mouse model of Camurati-Engelmann disease, a nonmalignant metabolic bone disorder associated with increased TGF-β activity. Thus, pathological TGF-β release from bone contributes to muscle weakness by decreasing Ca(2+)-induced muscle force production.

  5. Muscle Weakness and Speech in Oculopharyngeal Muscular Dystrophy

    ERIC Educational Resources Information Center

    Neel, Amy T.; Palmer, Phyllis M.; Sprouls, Gwyneth; Morrison, Leslie

    2015-01-01

    Purpose: We documented speech and voice characteristics associated with oculopharyngeal muscular dystrophy (OPMD). Although it is a rare disease, OPMD offers the opportunity to study the impact of myopathic weakness on speech production in the absence of neurologic deficits in a relatively homogeneous group of speakers. Methods: Twelve individuals…

  6. Peak torque, reaction time, and rate of torque development of hip abductors and adductors of older women.

    PubMed

    Morcelli, Mary Hellen; Rossi, Denise Martineli; Karuka, Aline Harumi; Crozara, Luciano Fernandes; Hallal, Camilla Zamfolini; Marques, Nise Ribeiro; Gonçalves, Mauro; Navega, Marcelo Tavella

    2016-01-01

    Impaired muscle function at the hip has been implicated to be a major factor related to falls in older adults. Therefore, the aim of this study was to analyze the rate of torque development (RTD), reaction time (RT), and peak torque (PT) of hip abductors and hip adductors in young women (YW), older women nonfallers (ONF), and older women fallers (OF). Eighteen YW and 44 older women divided among OF (n = 20) and ONF (n = 24) performed maximum isometric hip abductor and adduction contractions on a dynamometer. YW had 40% greater PT and 61.5% greater RTD for hip abductors than the ONF. Compared with OF, YW had 47.5% greater PT and 68% greater RTD. OF showed less RTD at 150 ms (31%) and 200 ms (34.5%) than ONF for hip abductors. PT of hip adductors was 52% greater in YW than in the two older groups, whereas RTD was 71% greater. OF showed less RTD than ONF for hip abductors according to standardized effect sizes. No RT differences were observed between the three groups. We conclude that older women (OF and ONF) have less strength and ability to develop force rapidly than YW for hip abductors and adductors. Low hip strength and slowed force development in ONF during hip abduction may increase fall risk in older women.

  7. Reconstruction of chronic abductor deficiency after revision hip arthroplasty using an extensor mechanism allograft.

    PubMed

    Drexler, M; Abolghasemian, M; Kuzyk, P R; Dwyer, T; Kosashvili, Y; Backstein, D; Gross, A E; Safir, O

    2015-08-01

    This study reports the clinical outcome of reconstruction of deficient abductor muscles following revision total hip arthroplasty (THA), using a fresh-frozen allograft of the extensor mechanism of the knee. A retrospective analysis was conducted of 11 consecutive patients with a severe limp because of abductor deficiency which was confirmed on MRI scans. The mean age of the patients (three men and eight women) was 66.7 years (52 to 84), with a mean follow-up of 33 months (24 to 41). Following surgery, two patients had no limp, seven had a mild limp, and two had a persistent severe limp (p = 0.004). The mean power of the abductors improved on the Medical Research Council scale from 2.15 to 3.8 (p < 0.001). Pre-operatively, all patients required a stick or walking frame; post-operatively, four patients were able to walk without an aid. Overall, nine patients had severe or moderate pain pre-operatively; ten patients had no or mild pain post-operatively. At final review, the Harris hip score was good in five patients, fair in two and poor in four. We conclude that using an extensor mechanism allograft is relatively effective in the treatment of chronic abductor deficiency of the hip after THA when techniques such as local tissue transfer are not possible. Longer-term follow-up is necessary before the technique can be broadly applied. PMID:26224820

  8. Factors That Influence Muscle Weakness Following Stroke and Their Clinical Implications: A Critical Review

    PubMed Central

    Gray, Vicki; Rice, Charles L.

    2012-01-01

    ABSTRACT Purpose: To provide a comprehensive review of changes that occur in the muscle after stroke and how these changes influence the force-generating capacity of the muscle. Methods: A literature search of PubMed, CINAHL, MEDLINE, and Embase was conducted using the search terms stroke, hemiparesis, muscle structure, cross sectional area, atrophy, force, velocity, and torque. There were 27 articles included in this review. Results: Three changes occur in the muscle after stroke: a decrease in muscle mass, a decrease in fibre length, and a smaller pennation angle. In addition, the tendon is stretched and becomes more compliant. All of these factors reduce the affected muscle's ability to generate forces similar to controls or to non-paretic muscles. The result is a leftward shift in the length–tension curve, a downward shift in the torque–angle curve, and a downward shift in the force–velocity curve. Conclusion: Changes in muscle architecture contributing to weakness, such as muscle-fibre length, pennation angle, muscle atrophy, and tendon compliance, should be prevented or reversed by means of an appropriate rehabilitation programme. PMID:23997398

  9. Distinct underlying mechanisms of limb and respiratory muscle fiber weaknesses in nemaline myopathy.

    PubMed

    Lindqvist, Johan; Cheng, Arthur J; Renaud, Guillaume; Hardeman, Edna C; Ochala, Julien

    2013-06-01

    Nemaline myopathy is the most common congenital myopathy and is caused by mutations in various genes such as ACTA1 (encoding skeletal α-actin). It is associated with limb and respiratory muscle weakness. Despite increasing clinical and scientific interest, the molecular and cellular events leading to such weakness remain unknown, which prevents the development of specific therapeutic interventions. To unravel the potential mechanisms involved, we dissected lower limb and diaphragm muscles from a knock-in mouse model of severe nemaline myopathy expressing the ACTA1 His40Tyr actin mutation found in human patients. We then studied a broad range of structural and functional characteristics assessing single-myofiber contraction, protein expression, and electron microscopy. One of the major findings in the diaphragm was the presence of numerous noncontractile areas (including disrupted sarcomeric structures and nemaline bodies). This greatly reduced the number of functional sarcomeres, decreased the force generation capacity at the muscle fiber level, and likely would contribute to respiratory weakness. In limb muscle, by contrast, there were fewer noncontractile areas and they did not seem to have a major role in the pathogenesis of weakness. These divergent muscle-specific results provide new important insights into the pathophysiology of severe nemaline myopathy and crucial information for future development of therapeutic strategies. PMID:23656990

  10. Transcriptomic analysis reveals abnormal muscle repair and remodeling in survivors of critical illness with sustained weakness

    PubMed Central

    Walsh, Christopher J.; Batt, Jane; Herridge, Margaret S.; Mathur, Sunita; Bader, Gary D.; Hu, Pingzhao; dos Santos, Claudia C.

    2016-01-01

    ICU acquired weakness (ICUAW) is a common complication of critical illness characterized by structural and functional impairment of skeletal muscle. The resulting physical impairment may persist for years after ICU discharge, with few patients regaining functional independence. Elucidating molecular mechanisms underscoring sustained ICUAW is crucial to understanding outcomes linked to different morbidity trajectories as well as for the development of novel therapies. Quadriceps muscle biopsies and functional measures of muscle strength and mass were obtained at 7 days and 6 months post-ICU discharge from a cohort of ICUAW patients. Unsupervised co-expression network analysis of transcriptomic profiles identified discrete modules of co-expressed genes associated with the degree of muscle weakness and atrophy in early and sustained ICUAW. Modules were enriched for genes involved in skeletal muscle regeneration and extracellular matrix deposition. Collagen deposition in persistent ICUAW was confirmed by histochemical stain. Modules were further validated in an independent cohort of critically ill patients with sepsis-induced multi-organ failure and a porcine model of ICUAW, demonstrating disease-associated conservation across species and peripheral muscle type. Our findings provide a pathomolecular basis for sustained ICUAW, implicating aberrant expression of distinct skeletal muscle structural and regenerative genes in early and persistent ICUAW. PMID:27411715

  11. Diaphragm Muscle Fiber Weakness and Ubiquitin–Proteasome Activation in Critically Ill Patients

    PubMed Central

    Hooijman, Pleuni E.; Beishuizen, Albertus; Witt, Christian C.; de Waard, Monique C.; Girbes, Armand R. J.; Spoelstra-de Man, Angelique M. E.; Niessen, Hans W. M.; Manders, Emmy; van Hees, Hieronymus W. H.; van den Brom, Charissa E.; Silderhuis, Vera; Lawlor, Michael W.; Labeit, Siegfried; Stienen, Ger J. M.; Hartemink, Koen J.; Paul, Marinus A.; Heunks, Leo M. A.

    2015-01-01

    Rationale: The clinical significance of diaphragm weakness in critically ill patients is evident: it prolongs ventilator dependency, and increases morbidity and duration of hospital stay. To date, the nature of diaphragm weakness and its underlying pathophysiologic mechanisms are poorly understood. Objectives: We hypothesized that diaphragm muscle fibers of mechanically ventilated critically ill patients display atrophy and contractile weakness, and that the ubiquitin–proteasome pathway is activated in the diaphragm. Methods: We obtained diaphragm muscle biopsies from 22 critically ill patients who received mechanical ventilation before surgery and compared these with biopsies obtained from patients during thoracic surgery for resection of a suspected early lung malignancy (control subjects). In a proof-of-concept study in a muscle-specific ring finger protein-1 (MuRF-1) knockout mouse model, we evaluated the role of the ubiquitin–proteasome pathway in the development of contractile weakness during mechanical ventilation. Measurements and Main Results: Both slow- and fast-twitch diaphragm muscle fibers of critically ill patients had approximately 25% smaller cross-sectional area, and had contractile force reduced by half or more. Markers of the ubiquitin–proteasome pathway were significantly up-regulated in the diaphragm of critically ill patients. Finally, MuRF-1 knockout mice were protected against the development of diaphragm contractile weakness during mechanical ventilation. Conclusions: These findings show that diaphragm muscle fibers of critically ill patients display atrophy and severe contractile weakness, and in the diaphragm of critically ill patients the ubiquitin–proteasome pathway is activated. This study provides rationale for the development of treatment strategies that target the contractility of diaphragm fibers to facilitate weaning. PMID:25760684

  12. Correcting myogenic ptosis accompanying extraocular muscle weakness: The "Bobby Pin" procedure.

    PubMed

    Vemuri, Swapna; Christianson, Murray D; Demirci, Hakan

    2016-10-01

    This article evaluates the "Bobby Pin" procedure in the correction of myogenic ptosis accompanying extraocular muscle weakness. We retrospectively reviewed 26 eyelids of 13 patients who underwent "Bobby Pin" procedure for myogenic ptosis accompanying extraocular muscle weakness. We evaluated the patients' clinical features such as age, etiology of ptosis, symptoms, standard ptosis measurements, associated systemic diseases, additional ophthalmic conditions, complications, and recurrence. Etiology of myogenic ptosis and extraocular muscle weakness was oculopharyngeal dystrophy in 4 (31%) patients, chronic progressive external ophthalmoplegia in 4 (31%) patients, myotonic dystrophy in 2 (23%) patients, and idiopathic in 3 (15%) patients. The mean levator function was approximately 5 mm pre- and post-operatively (range 1 to 12 mm). The mean margin-to-reflex distance 1 increased from -1.1 mm (below the light reflex) pre-operatively to +0.4 mm (above the light reflex) post-operatively. After a mean follow-up of 40 months, only 1 (8%) patient experienced ptosis recurrence. Upper eyelids were symmetric in both contour and height in all patients. Mild superficial keratopathy involving less than 10% of cornea was observed in 4 (31%) patients. The "Bobby Pin" procedure is an effective and long-lasting treatment option for correcting acquired ptosis accompanying extraocular muscle weakness. The procedure is safe, simple, easily learned, time- and cost-effective, and does not require any expensive equipment. PMID:27541941

  13. Epigenetic changes as a common trigger of muscle weakness in congenital myopathies.

    PubMed

    Rokach, Ori; Sekulic-Jablanovic, Marijana; Voermans, Nicol; Wilmshurst, Jo; Pillay, Komala; Heytens, Luc; Zhou, Haiyan; Muntoni, Francesco; Gautel, Mathias; Nevo, Yoram; Mitrani-Rosenbaum, Stella; Attali, Ruben; Finotti, Alessia; Gambari, Roberto; Mosca, Barbara; Jungbluth, Heinz; Zorzato, Francesco; Treves, Susan

    2015-08-15

    Congenital myopathies are genetically and clinically heterogeneous conditions causing severe muscle weakness, and mutations in the ryanodine receptor gene (RYR1) represent the most frequent cause of these conditions. A common feature of diseases caused by recessive RYR1 mutations is a decrease of ryanodine receptor 1 protein content in muscle. The aim of the present investigation was to gain mechanistic insight into the causes of this reduced ryanodine receptor 1. We found that muscle biopsies of patients with recessive RYR1 mutations exhibit decreased expression of muscle-specific microRNAs, increased DNA methylation and increased expression of class II histone deacetylases. Transgenic mouse muscle fibres over-expressing HDAC-4/HDAC-5 exhibited decreased expression of RYR1 and of muscle-specific miRNAs, whereas acute knock-down of RYR1 in mouse muscle fibres by siRNA caused up-regulation of HDAC-4/HDAC-5. Intriguingly, increased class II HDAC expression and decreased ryanodine receptor protein and miRNAs expression were also observed in muscles of patients with nemaline myopathy, another congenital neuromuscular disorder. Our results indicate that a common pathophysiological pathway caused by epigenetic changes is activated in some forms of congenital neuromuscular disorders. PMID:26019235

  14. Changes in Knee Biomechanics After a Hip-Abductor Strengthening Protocol for Runners With Patellofemoral Pain Syndrome

    PubMed Central

    Ferber, Reed; Kendall, Karen D.; Farr, Lindsay

    2011-01-01

    Abstract Context: Very few authors have investigated the relationship between hip-abductor muscle strength and frontal-plane knee mechanics during running. Objective: To investigate this relationship using a 3-week hip-abductor muscle-strengthening program to identify changes in strength, pain, and biomechanics in runners with patellofemoral pain syndrome (PFPS). Design: Cohort study. Setting: University-based clinical research laboratory. Patients or Other Participants: Fifteen individuals (5 men, 10 women) with PFPS and 10 individuals without PFPS (4 men, 6 women) participated. Intervention(s): The patients with PFPS completed a 3-week hip-abductor strengthening protocol; control participants did not. Main Outcome Measure(s): The dependent variables of interest were maximal isometric hip-abductor muscle strength, 2-dimensional peak knee genu valgum angle, and stride-to-stride knee-joint variability. All measures were recorded at baseline and 3 weeks later. Between-groups differences were compared using repeated-measures analyses of variance. Results: At baseline, the PFPS group exhibited reduced strength, no difference in peak genu valgum angle, and increased stride-to-stride knee-joint variability compared with the control group. After the 3-week protocol, the PFPS group demonstrated increased strength, less pain, no change in peak genu valgum angle, and reduced stride-to-stride knee-joint variability compared with baseline. Conclusions: A 3-week hip-abductor muscle-strengthening protocol was effective in increasing muscle strength and decreasing pain and stride-to-stride knee-joint variability in individuals with PFPS. However, concomitant changes in peak knee genu valgum angle were not observed. PMID:21391799

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

    PubMed

    Anvar, Seyed Yahya; Raz, Yotam; Verway, Nisha; van der Sluijs, Barbara; Venema, Andrea; Goeman, Jelle J; Vissing, John; van der Maarel, Silvère M; 't Hoen, Peter A C; van Engelen, Baziel G M; Raz, Vered

    2013-06-01

    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<0.05). Using k-means clustering we identified age-dependent trends in both OPMD and controls, but trends were often accelerated in OPMD. We report an age-regulated decline in PABPN1 levels in Vastus lateralis muscles from the fifth decade. In concurrence with severe muscle degeneration in OPMD, the decline in PABPN1 accelerated in OPMD and was specific to skeletal muscles. Reduced PABPN1 levels (30% to 60%) in muscle cells induced myogenic defects and morphological signatures of cellular aging in proportion to PABPN1 expression levels. We suggest that PABPN1 levels regulate muscle cell aging and OPMD represents an accelerated muscle aging disorder.

  16. Disrupted myosin cross-bridge cycling kinetics triggers muscle weakness in nebulin-related myopathy.

    PubMed

    Ochala, Julien; Lehtokari, Vilma-Lotta; Iwamoto, Hiroyuki; Li, Meishan; Feng, Han-Zhong; Jin, Jian-Ping; Yagi, Naoto; Wallgren-Pettersson, Carina; Pénisson-Besnier, Isabelle; Larsson, Lars

    2011-06-01

    Nebulin is a giant protein expressed at high levels in skeletal muscle. Mutations in the nebulin gene (NEB) lead to muscle weakness and various congenital myopathies. Despite increasing clinical and scientific interest, the pathogenesis of weakness remains unknown. The present study, therefore, aims at unraveling the underlying molecular mechanisms. Hence, we recorded and analyzed the mechanics as well as the X-ray diffraction patterns of human membrane-permeabilized single muscle fibers expressing nebulin mutations. Results demonstrated that, during contraction, the cycling rate of myosin heads attaching to actin is dramatically perturbed, causing a reduction in the fraction of myosin-actin interactions in the strong binding state. This phenomenon prevents complete thin-filament activation, more especially proper and full tropomyosin movement, further limiting additional binding of myosin cross-bridges. At the cell level, this reduces the force-generating capacity and, overall, provokes muscle weakness. To reverse such a negative cascade of events, future potential therapeutic interventions should, therefore, focus on the triggering component, the altered myosin cross-bridge cycling kinetics. PMID:21350120

  17. Fast skeletal muscle troponin activation increases force of mouse fast skeletal muscle and ameliorates weakness due to nebulin-deficiency.

    PubMed

    Lee, Eun-Jeong; De Winter, Josine M; Buck, Danielle; Jasper, Jeffrey R; Malik, Fady I; Labeit, Siegfried; Ottenheijm, Coen A; Granzier, Henk

    2013-01-01

    The effect of the fast skeletal muscle troponin activator, CK-2066260, on calcium-induced force development was studied in skinned fast skeletal muscle fibers from wildtype (WT) and nebulin deficient (NEB KO) mice. Nebulin is a sarcomeric protein that when absent (NEB KO mouse) or present at low levels (nemaline myopathy (NM) patients with NEB mutations) causes muscle weakness. We studied the effect of fast skeletal troponin activation on WT muscle and tested whether it might be a therapeutic mechanism to increase muscle strength in nebulin deficient muscle. We measured tension-pCa relations with and without added CK-2066260. Maximal active tension in NEB KO tibialis cranialis fibers in the absence of CK-2066260 was ∼60% less than in WT fibers, consistent with earlier work. CK-2066260 shifted the tension-calcium relationship leftwards, with the largest relative increase (up to 8-fold) at low to intermediate calcium levels. This was a general effect that was present in both WT and NEB KO fiber bundles. At pCa levels above ∼6.0 (i.e., calcium concentrations <1 µM), CK-2066260 increased tension of NEB KO fibers to beyond that of WT fibers. Crossbridge cycling kinetics were studied by measuring k(tr) (rate constant of force redevelopment following a rapid shortening/restretch). CK-2066260 greatly increased k(tr) at submaximal activation levels in both WT and NEB KO fiber bundles. We also studied the sarcomere length (SL) dependence of the CK-2066260 effect (SL 2.1 µm and 2.6 µm) and found that in the NEB KO fibers, CK-2066260 had a larger effect on calcium sensitivity at the long SL. We conclude that fast skeletal muscle troponin activation increases force at submaximal activation in both wildtype and NEB KO fiber bundles and, importantly, that this troponin activation is a potential therapeutic mechanism for increasing force in NM and other skeletal muscle diseases with loss of muscle strength. PMID:23437068

  18. The spectrum of muscle histopathologic findings in 42 weak scleroderma patients

    PubMed Central

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

    2015-01-01

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

  19. Correlation between distribution of muscle weakness, electrophysiological findings and CTG expansion in myotonic dystrophy.

    PubMed

    Khoshbakht, Roya; Soltanzadeh, Akbar; Zamani, Babak; Abdi, Siyamak; Gharagozli, Kourosh; Kahrizi, Kimia; Khoshbakht, Rahem; Nafissi, Shahriar

    2014-07-01

    Myotonic dystrophy type 1 (DM-1) is a multi-system disorder affecting the muscles, brain, cardiovascular system, endocrine system, eyes and skin. Diagnosis is made by clinical, electrodiagnostic and genetic studies. This study aimed to determine the correlation between CTG expansion and distribution of muscle weakness and clinical and electrophysiological findings. Genetically confirmed DM-1 patients presenting to Shariati Hospital between 2005 and 2011 were included in this study. Clinical, electrodiagnostic and genetic testing was performed and the correlation between CTG expansion and distribution of muscle weakness and clinical and electromyographic findings was studied. Thirty-three genetically confirmed DM-1 patients were enrolled. Myotonia, bifacial weakness and distal upper limb weakness were seen in all patients. Diabetes mellitus was found in one patient (3%), cardiac disturbance in eight (24.2%), cataracts in eight (24.2%), hypogonadism in five (15.2%), frontal baldness in 13 (39.4%), temporalis wasting in 14 (42.4%), temporomandibular joint disorder in seven (21.2%) and mental retardation in eight (24.2%). The mean number of CTG repeats, measured by Southern blot, was 8780 (range 500-15,833). A negative correlation was found between CTG expansion and age of onset. Temporalis wasting and mental retardation were positively correlated with CTG expansion. No relationship was found between weakness distribution, electromyographic findings, other systemic features and CTG expansion. In this study of DM-1 in Iran, we found a correlation between CTG expansion and age of onset, temporalis wasting and mental disability. No correlation between CTG expansion and electrodiagnostic and other clinical findings were detected.

  20. Mechanism of quadriceps femoris muscle weakness in patients with anterior cruciate ligament reconstruction.

    PubMed

    Konishi, Y; Fukubayashi, T; Takeshita, D

    2002-12-01

    The purpose of this study was to investigate gamma loop function in the quadriceps femoris muscle in patients who with less than 6 month-history of anterior cruciate ligament (ACL) reconstruction. For this purpose, we compared the response to vibration stimulation in 10 patients with ACL repair and 12 normal healthy subjects, by measuring the maximal voluntary isometric contraction (MVC) and integrated electromyograms (I-EMG) of the quadriceps muscles. Pre-vibration data were obtained from each subject by measuring the MVC of the knee extension and the I-EMG from the vastus medialis, vastus lateralis, and rectus femoris muscles. Vibration stimulation was applied to the infrapatellar tendons, followed immediately by repeating the MVC and I-EMG recording. Prolonged vibration resulted in a significant decrease of both MVC and I-EMG in the control group. In contrast, the same stimulus failed to elicit changes in ACL-repair group. Our results suggest the presence of abnormal gamma loop function in the quadriceps femoris muscle of patients with ACL repair, which may explain the muscle weakness often described in such patients.

  1. Changes in cross-bridge cycling underlie muscle weakness in patients with tropomyosin 3-based myopathy.

    PubMed

    Ottenheijm, Coen A C; Lawlor, Michael W; Stienen, Ger J M; Granzier, Henk; Beggs, Alan H

    2011-05-15

    Nemaline myopathy, the most common non-dystrophic congenital myopathy, is caused by mutations in six genes, all of which encode thin-filament proteins, including NEB (nebulin) and TPM3 (α tropomyosin). In contrast to the mechanisms underlying weakness in NEB-based myopathy, which are related to loss of thin-filament functions normally exerted by nebulin, the pathogenesis of muscle weakness in patients with TPM3 mutations remains largely unknown. Here, we tested the hypothesis that the contractile phenotype of TPM3-based myopathy is different from that of NEB-based myopathy and that this phenotype is a direct consequence of the loss of the specific functions normally exerted by tropomyosin. To test this hypothesis, we used a multidisciplinary approach, including muscle fiber mechanics and confocal and electron microscopy to characterize the structural and functional phenotype of muscle fibers from five patients with TPM3-based myopathy and compared this with that of unaffected control subjects. Our findings demonstrate that patients with TPM3-based myopathy display a contractile phenotype that is very distinct from that of patients with NEB-based myopathy. Whereas both show severe myofilament-based muscle weakness, the contractile dysfunction in TPM3-based myopathy is largely explained by changes in cross-bridge cycling kinetics, but not by the dysregulation of sarcomeric thin-filament length that plays a prominent role in NEB-based myopathy. Interestingly, the loss of force-generating capacity in TPM3-based myopathy appears to be compensated by enhanced thin-filament activation. These findings provide a scientific basis for differential therapeutics aimed at restoring contractile performance in patients with TPM3-based versus NEB-based myopathy. PMID:21357678

  2. Abductor pollicis longus tendon division with swan neck thumb deformity.

    PubMed

    Zacharia, Balaji; Puthezhath, Kishore

    2012-08-01

    Swan neck thumb deformity can be caused by osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, tendon transfers and paralytic diseases. Abductor pollicis longus is one of the major stabilizing tendon of the carpometacarpal joint of thumb. To the best of our knowledge, swan neck thumb deformity owing to division of abductor pollicis longus tendon is rare. In this article, we describe a case of isolated division of abductor pollicis longus tendon presenting with swan-neck deformity of thumb and discuss the mechanism, management and outcome. The patient was treated by repair of the divided tendon using palmaris longus tendon graft. At approximately 107 weeks following treatment, the patient was having full range of thumb movement and the deformity completely disappeared. We also describe the unusual mechanism whereby an isolated division of abductor pollicis longus tendon results in swan neck thumb deformity. Level of clinical evidence IV. PMID:22825877

  3. Chemotherapy-Induced Weakness and Fatigue in Skeletal Muscle: The Role of Oxidative Stress

    PubMed Central

    St. Clair, Daret K.

    2011-01-01

    Abstract Significance Fatigue is one of the most common symptoms of cancer and its treatment, manifested in the clinic through weakness and exercise intolerance. These side effects not only compromise patient's quality of life (QOL), but also diminish physical activity, resulting in limited treatment and increased morbidity. Recent Advances Oxidative stress, mediated by cancer or chemotherapeutic agents, is an underlying mechanism of the drug-induced toxicity. Nontargeted tissues, such as striated muscle, are severely affected by oxidative stress during chemotherapy, leading to toxicity and dysfunction. Critical Issues These findings highlight the importance of investigating clinically applicable interventions to alleviate the debilitating side effects. This article discusses the clinically available chemotherapy drugs that cause fatigue and oxidative stress in cancer patients, with an in-depth focus on the anthracycline doxorubicin. Doxorubicin, an effective anticancer drug, is a primary example of how chemotherapeutic agents disrupt striated muscle function through oxidative stress. Future Directions Further research investigating antioxidants could provide relief for cancer patients from debilitating muscle weakness, leading to improved quality of life. Antioxid. Redox Signal. 15, 2543–2563. PMID:21457105

  4. Age-related weakness of proximal muscle studied with motor cortical mapping: a TMS study.

    PubMed

    Plow, Ela B; Varnerin, Nicole; Cunningham, David A; Janini, Daniel; Bonnett, Corin; Wyant, Alexandria; Hou, Juliet; Siemionow, Vlodek; Wang, Xiao-Feng; Machado, Andre G; Yue, Guang H

    2014-01-01

    Aging-related weakness is due in part to degeneration within the central nervous system. However, it is unknown how changes to the representation of corticospinal output in the primary motor cortex (M1) relate to such weakness. Transcranial magnetic stimulation (TMS) is a noninvasive method of cortical stimulation that can map representation of corticospinal output devoted to a muscle. Using TMS, we examined age-related alterations in maps devoted to biceps brachii muscle to determine whether they predicted its age-induced weakness. Forty-seven right-handed subjects participated: 20 young (22.6 ± 0.90 years) and 27 old (74.96 ± 1.35 years). We measured strength as force of elbow flexion and electromyographic activation of biceps brachii during maximum voluntary contraction. Mapping variables included: 1) center of gravity or weighted mean location of corticospinal output, 2) size of map, 3) volume or excitation of corticospinal output, and 4) response density or corticospinal excitation per unit area. Center of gravity was more anterior in old than in young (p<0.001), though there was no significant difference in strength between the age groups. Map size, volume, and response density showed no significant difference between groups. Regardless of age, center of gravity significantly predicted strength (β = -0.34, p = 0.005), while volume adjacent to the core of map predicted voluntary activation of biceps (β = 0.32, p = 0.008). Overall, the anterior shift of the map in older adults may reflect an adaptive change that allowed for the maintenance of strength. Laterally located center of gravity and higher excitation in the region adjacent to the core in weaker individuals could reflect compensatory recruitment of synergistic muscles. Thus, our study substantiates the role of M1 in adapting to aging-related weakness and subtending strength and muscle activation across age groups. Mapping from M1 may offer foundation for an examination of mechanisms that preserve

  5. Q-angle in patellofemoral pain: relationship with dynamic knee valgus, hip abductor torque, pain and function☆

    PubMed Central

    Almeida, Gabriel Peixoto Leão; Silva, Ana Paula de Moura Campos Carvalho e; França, Fábio Jorge Renovato; Magalhães, Maurício Oliveira; Burke, Thomaz Nogueira; Marques, Amélia Pasqual

    2016-01-01

    Objective To investigate the relationship between the q-angle and anterior knee pain severity, functional capacity, dynamic knee valgus and hip abductor torque in women with patellofemoral pain syndrome (PFPS). Methods This study included 22 women with PFPS. The q-angle was assessed using goniometry: the participants were positioned in dorsal decubitus with the knee and hip extended, and the hip and foot in neutral rotation. Anterior knee pain severity was assessed using a visual analog scale, and functional capacity was assessed using the anterior knee pain scale. Dynamic valgus was evaluated using the frontal plane projection angle (FPPA) of the knee, which was recorded using a digital camera during step down, and hip abductor peak torque was recorded using a handheld dynamometer. Results The q-angle did not present any significant correlation with severity of knee pain (r = −0.29; p = 0.19), functional capacity (r = −0.08; p = 0.72), FPPA (r = −0.28; p = 0.19) or isometric peak torque of the abductor muscles (r = −0.21; p = 0.35). Conclusion The q-angle did not present any relationship with pain intensity, functional capacity, FPPA, or hip abductor peak torque in the patients with PFPS. PMID:27069887

  6. Hip-Abductor Fatigue and Single-Leg Landing Mechanics in Women Athletes

    PubMed Central

    Patrek, Mary F.; Kernozek, Thomas W.; Willson, John D.; Wright, Glenn A.; Doberstein, Scott T.

    2011-01-01

    Abstract Context: Reduced hip-abductor strength and muscle activation may be associated with altered lower extremity mechanics, which are thought to increase the risk for anterior cruciate ligament injury. However, experimental evidence supporting this relationship is limited. Objective: To examine the changes in single-leg landing mechanics and gluteus medius recruitment that occur after a hip-abductor fatigue protocol. Design: Descriptive laboratory study. Patients or Other Participants: Twenty physically active women (age  =  21.0 ± 1.3 years). Intervention(s): Participants were tested before (prefatigue) and after (postfatigue) a hip-abductor fatigue protocol consisting of repetitive side-lying hip abduction. Main Outcome Measure(s): Outcome measures included sagittal-plane and frontal-plane hip and knee kinematics at initial contact and at 60 milliseconds after initial contact during 5 single-leg landings from a height of 40 cm. Peak hip and knee sagittal-plane and frontal-plane joint moments during this time interval were also analyzed. Measures of gluteus medius activation, including latency, peak amplitude, and integrated signal, were recorded. Results: A small (<1°) increase in hip-abduction angle at initial contact and a small (<1°) decrease in knee-abduction (valgus) angle at 60 milliseconds after contact were observed in the postfatigue landing condition. No other kinematic changes were noted for the knee or hip at initial contact or at 60 milliseconds after initial contact. Peak external knee-adduction moment decreased 27% and peak hip adduction moment decreased 24% during the postfatigue landing condition. Gluteus medius activation was delayed after the protocol, but no difference in peak or integrated signal was seen during the landing trials. Conclusions: Changes observed during single-leg landings after hip-abductor fatigue were not generally considered unfavorable to the integrity of the anterior cruciate ligament. Further work may be

  7. Muscle weakness is related to slip-initiated falls among community-dwelling older adults.

    PubMed

    Ding, Li; Yang, Feng

    2016-01-25

    The purposes of this study were (1) to investigate the relationship between muscle weakness and slip-related falls among community-dwelling older adults, and (2) to determine optimal cut-off values with respect to the knee strength capacity which can be used to identify individuals at high risk of falls. Thirty-six healthy older adults participated in this study. Their muscle strength (torque) was assessed at the right knee under maximum voluntary isometric (flexion and extension) contractions. They were then moved to a special treadmill. After walking regularly five times on the treadmill, they experienced an identical and unannounced slip during walking on the treadmill with the protection of a safety harness. This treadmill could be considered a standardized platform, inducing an unexpected slip. Accuracy of predicting slip outcome (fall vs. recovery) was examined for both strength measurements (i.e., the strength capacity of knee extensor and flexor) using univariate logistic regressions. The optimal cutoff values for the two strength measurements were determined by the receiver operating characteristic analysis. Results showed that fallers displayed significantly lower knee strength capacities compared to their recovery counterpart (1.10 vs. 1.44Nm/kg, p<0.01, effect size Cohen׳s d=0.95 for extensor; 0.93 vs. 1.13Nm/kg, p<0.05, d=0.69 for flexor). Such results suggested that muscle weakness contributes to falls initiated by a slip during gait. Our findings could provide guidance to identify individuals at increased risk of falling using the derived optimal cutoff values of knee strength capacity among older adults.

  8. First results about recovery of walking function in patients with intensive care unit-acquired muscle weakness from the General Weakness Syndrome Therapy (GymNAST) cohort study

    PubMed Central

    Mehrholz, Jan; Mückel, Simone; Oehmichen, Frank; Pohl, Marcus

    2015-01-01

    Objectives To describe the time course of recovery of walking function and other activities of daily living in patients with intensive care unit (ICU)-acquired muscle weakness. Design This is a cohort study. Participants We included critically ill patients with ICU-acquired muscle weakness. Setting Post-acute ICU and rehabilitation units in Germany. Measures We measured walking function, muscle strength, activities in daily living, motor and cognitive function. Results We recruited 150 patients (30% female) who fulfilled our inclusion and exclusion criteria. The primary outcome recovery of walking function was achieved after a median of 28.5 days (IQR=45) after rehabilitation onset and after a median of 81.5 days (IQR=64) after onset of illness. Our final multivariate model for recovery of walking function included two clinical variables from baseline: the Functional Status Score ICU (adjusted HR=1.07 (95% CI 1.03 to 1.12) and the ability to reach forward in cm (adjusted HR=1.02 (95% CI 1.00 to 1.04). All secondary outcomes but not pain improved significantly in the first 8 weeks after study onset. Conclusions We found good recovery of walking function for most patients and described the recovery of walking function of people with ICU-acquired muscle weakness. Trials registrations number Sächsische Landesärztekammer EK-BR-32/13-1; DRKS00007181, German Register of Clinical Trials. PMID:26700274

  9. Effect of Gender, Disease Duration and Treatment on Muscle Strength in Myasthenia Gravis

    PubMed Central

    Citirak, Gülsenay; Cejvanovic, Sanja; Andersen, Henning; Vissing, John

    2016-01-01

    Introduction The aim of this observational, cross-sectional study was to quantify the potential presence of muscle weakness among patients with generalized myasthenia gravis (gMG). The influence of gender, treatment intensity and disease duration on muscle strength and disease progression was also assessed. Methods Muscle strength was tested in 8 muscle groups by manual muscle testing and by hand-held dynamometry in 107 patients with gMG and 89 healthy age- and gender-matched controls. Disease duration, severity and treatment history were reviewed and compared with muscle strength. Results Patients had reduced strength in all tested muscle group compared to control subjects (p<0.05). Women with gMG were stronger than men (decrease in strength 22.6% vs. 32.7% in men, P<0.05). Regional differences in muscle weakness were also evident, with proximal muscles being more affected. Interestingly, muscle strength did not correlate with disease duration and treatment intensity. Conclusions The results of this study show that in patients with gMG; 1) there is significant muscle weakness, 2) muscle weakness is more pronounced in men than women, 3) shoulder abductors, hip flexors, and neck muscles are the most affected muscle groups and 4) disease duration or treatment intensity alone are not predictors of loss of muscle strength in gMG. PMID:27741232

  10. Effect of weak static magnetic fields on the development of cultured skeletal muscle cells.

    PubMed

    Surma, Sergei V; Belostotskaya, Galina B; Shchegolev, Boris F; Stefanov, Vasily E

    2014-12-01

    We studied the effect produced on the development and functional activity of skeletal muscle cells from newborn Wistar rats in primary culture by weak static magnetic fields (WSMF; 60-400 µT) with a high capacity of penetrating the biological media. To reduce the impact of external magnetic fields, cells were cultured at 37 °C in a multilayered shielding chamber with the attenuation coefficient equal to 160. WSMF inside the chamber was created by a circular permanent magnet. We found that the application of WSMF with the magnetic field strength only a few times that of the geomagnetic field can accelerate the development of skeletal muscle cells, resulting in the formation of multinuclear hypertrophied myotubes. WSMF was shown to induce 1.5- to 3.5-fold rise in the concentration of intracellular calcium [Ca(2+)]i due to the release of Ca(2+) from the sarcoplasmic reticulum (SR) through ryanodine receptors (RyR), which increases in the maturation of myotubes. We also found that fully differentiated myotubes at late stages of development were less sensitive to WSMF, manifesting a gradual decrease in the frequency of contractions. However, myotubes at the stage when electromechanical coupling was forming dramatically reduced the frequency of contractions during the first minutes of their exposure to WSMF.

  11. Nemaline myopathy-related skeletal muscle α-actin (ACTA1) mutation, Asp286Gly, prevents proper strong myosin binding and triggers muscle weakness.

    PubMed

    Ochala, Julien; Ravenscroft, Gianina; Laing, Nigel G; Nowak, Kristen J

    2012-01-01

    Many mutations in the skeletal muscle α-actin gene (ACTA1) lead to muscle weakness and nemaline myopathy. Despite increasing clinical and scientific interest, the molecular and cellular pathogenesis of weakness remains unclear. Therefore, in the present study, we aimed at unraveling these mechanisms using muscles from a transgenic mouse model of nemaline myopathy expressing the ACTA1 Asp286Gly mutation. We recorded and analyzed the mechanics of membrane-permeabilized single muscle fibers. We also performed molecular energy state computations in the presence or absence of Asp286Gly. Results demonstrated that during contraction, the Asp286Gly acts as a "poison-protein" and according to the computational analysis it modifies the actin-actin interface. This phenomenon is likely to prevent proper myosin cross-bridge binding, limiting the fraction of actomyosin interactions in the strong binding state. At the cell level, this decreases the force-generating capacity, and, overall, induces muscle weakness. To counterbalance such negative events, future potential therapeutic strategies may focus on the inappropriate actin-actin interface or myosin binding. PMID:23029319

  12. Persons with Chronic Hip Joint Pain Exhibit Reduced Hip Muscle Strength

    PubMed Central

    Mueller, Michael J.; Sahrmann, Shirley A.; Bloom, Nancy J.; Steger-May, Karen; Clohisy, John C.; Salsich, Gretchen B.

    2014-01-01

    STUDY DESIGN Controlled Laboratory Cross-Sectional Study OBJECTIVES To assess strength differences of the hip rotator and abductor muscle groups in young adults with chronic hip joint pain (CHJP) and asymptomatic controls. A secondary objective was to determine if strength in the uninvolved hip of those with unilateral CHJP differs from asymptomatic controls. BACKGROUND Little is known about the relationship between hip muscle strength and CHJP in young adults. METHODS 35 participants with CHJP and 35 matched controls (18 to 40 years of age) participated. Using hand-held dynamometry, strength of the hip external rotators (ERs) and internal rotators (IRs) was assessed with the hip flexed to 90° (ERs90°, IRs90°) and 0° (ERs0°, IRs0°). To assess ER and IR strength, the hip was placed at the end-range of external rotation and internal rotation, respectively. Strength of the hip abductors (ABDs) was assessed in sidelying, with the hip in 15° of abduction. Break tests were performed to determine maximum muscle force and the average torque was calculated using the corresponding moment arm. Independent samples t-tests were used to compare strength values between the 1) involved limb in participants with CHJP and corresponding limb in the matched controls and 2) the uninvolved limb in participants with unilateral CHJP and corresponding limb in the matched controls. RESULTS Compared to controls, participants with CHJP demonstrated weakness of 16–28%, (P<0.01) in all muscle groups tested in the involved hip. The uninvolved hip of 22 subjects with unilateral CHJP demonstrated weakness of 18% and 16% (P<0.05) in the ERs0° and ABDs, respectively when compared to the corresponding limb of the matched controls. CONCLUSION Our results demonstrate that persons with CHJP have weakness in the hip rotator and hip abductor muscles. Weakness also was found in the uninvolved hip of persons with CHJP. PMID:25299750

  13. Enzyme replacement therapy rescues weakness and improves muscle pathology in mice with X-linked myotubular myopathy

    PubMed Central

    Lawlor, Michael W.; Armstrong, Dustin; Viola, Marissa G.; Widrick, Jeffrey J.; Meng, Hui; Grange, Robert W.; Childers, Martin K.; Hsu, Cynthia P.; O'Callaghan, Michael; Pierson, Christopher R.; Buj-Bello, Anna; Beggs, Alan H.

    2013-01-01

    No effective treatment exists for patients with X-linked myotubular myopathy (XLMTM), a fatal congenital muscle disease caused by deficiency of the lipid phosphatase, myotubularin. The Mtm1δ4 and Mtm1 p.R69C mice model severely and moderately symptomatic XLMTM, respectively, due to differences in the degree of myotubularin deficiency. Contractile function of intact extensor digitorum longus (EDL) and soleus muscles from Mtm1δ4 mice, which produce no myotubularin, is markedly impaired. Contractile forces generated by chemically skinned single fiber preparations from Mtm1δ4 muscle were largely preserved, indicating that weakness was largely due to impaired excitation contraction coupling. Mtm1 p.R69C mice, which produce small amounts of myotubularin, showed impaired contractile function only in EDL muscles. Short-term replacement of myotubularin with a prototypical targeted protein replacement agent (3E10Fv-MTM1) in Mtm1δ4 mice improved contractile function and muscle pathology. These promising findings suggest that even low levels of myotubularin protein replacement can improve the muscle weakness and reverse the pathology that characterizes XLMTM. PMID:23307925

  14. Knee extensor muscle weakness is a risk factor for development of knee osteoarthritis. A systematic review and meta-analysis.

    PubMed

    Øiestad, B E; Juhl, C B; Eitzen, I; Thorlund, J B

    2015-02-01

    The objective of this study was to perform a systematic review and meta-analysis on the association between knee extensor muscle weakness and the risk of developing knee osteoarthritis. A systematic review and meta-analysis was conducted with literature searches in Medline, SPORTDiscus, EMBASE, CINAHL, and AMED. Eligible studies had to include participants with no radiographic or symptomatic knee osteoarthritis at baseline; have a follow-up time of a minimum of 2 years, and include a measure of knee extensor muscle strength. Hierarchies for extracting data on knee osteoarthritis and knee extensor muscle strength were defined prior to data extraction. Meta-analysis was applied on the basis of the odds ratios (ORs) of developing symptomatic knee osteoarthritis or radiographic knee osteoarthritis in subjects with knee extensor muscle weakness. ORs for knee osteoarthritis and 95% confidence intervals (CI) were estimated and combined using a random effects model. Twelve studies were eligible for inclusion in the meta-analysis after the initial searches. Five cohort studies with a follow-up time between 2.5 and 14 years, and a total number of 5707 participants (3553 males and 2154 females), were finally included. The meta-analysis showed an overall increased risk of developing symptomatic knee osteoarthritis in participants with knee extensor muscle weakness (OR 1.65 95% CI 1.23, 2.21; I(2) = 50.5%). This systematic review and meta-analysis showed that knee extensor muscle weakness was associated with an increased risk of developing knee osteoarthritis in both men and women.

  15. Characteristic MRI Findings of upper Limb Muscle Involvement in Myotonic Dystrophy Type 1

    PubMed Central

    Sugie, Kazuma; Sugie, Miho; Taoka, Toshio; Tonomura, Yasuyo; Kumazawa, Aya; Izumi, Tesseki; Kichikawa, Kimihiko; Ueno, Satoshi

    2015-01-01

    The objective of our study was to evaluate the relation between muscle MRI findings and upper limb weakness with grip myotonia in patients with myotonic dystrophy type 1 (DM1). Seventeen patients with DM1 were evaluated by manual muscle strength testing and muscle MRI of the upper limbs. Many DM1 patients presenting with decreased grasping power frequently showed high intensity signals in the flexor digitorum profundus (FDP) muscles on T1-weighted imaging. Patients presenting with upper limb weakness frequently also showed high intensity signals in the flexor pollicis longus, abductor pollicis longus, and extensor pollicis muscles. Disturbances of the distal muscles of the upper limbs were predominant in all DM1 patients. Some DM1 patients with a prolonged disease duration showed involvement of not only distal muscles but also proximal muscles in the upper limbs. Muscle involvement of the upper limbs on MRI strongly correlated positively with the disease duration or the numbers of CTG repeats. To our knowledge, this is the first study to provide a detailed description of the distribution and severity of affected muscles of the upper limbs on MRI in patients with DM1. We conclude that muscle MRI findings are very useful for identifying affected muscles and predicting the risk of muscle weakness in the upper limbs of DM1 patients. PMID:25919300

  16. High Prevalence of Respiratory Muscle Weakness in Hospitalized Acute Heart Failure Elderly Patients

    PubMed Central

    Verissimo, Pedro; Timenetsky, Karina T.; Casalaspo, Thaisa Juliana André; Gonçalves, Louise Helena Rodrigues; Yang, Angela Shu Yun; Eid, Raquel Caserta

    2015-01-01

    Introduction Respiratory Muscle Weakness (RMW) has been defined when the maximum inspiratory pressure (MIP) is lower than 70% of the predictive value. The prevalence of RMW in chronic heart failure patients is 30 to 50%. So far there are no studies on the prevalence of RMW in acute heart failure (AHF) patients. Objectives Evaluate the prevalence of RMW in patients admitted because of AHF and the condition of respiratory muscle strength on discharge from the hospital. Methods Sixty-three patients had their MIP measured on two occasions: at the beginning of the hospital stay, after they had reached respiratory, hemodynamic and clinical stability and before discharge from the hospital. The apparatus and technique to measure MIP were adapted because of age-related limitations of the patients. Data on cardiac ejection fraction, ECG, brain natriuretic peptide (BNP) levels and on the use of noninvasive ventilation (NIV) were collected. Results The mean age of the 63 patients under study was 75 years. On admission the mean ejection fraction was 33% (95% CI: 31–35) and the BNP hormone median value was 726.5 pg/ml (range: 217 to 2283 pg/ml); 65% of the patients used NIV. The median value of MIP measured after clinical stabilization was -52.7 cmH2O (range: -20 to -120 cmH2O); 76% of the patients had MIP values below 70% of the predictive value. On discharge, after a median hospital stay of 11 days, the median MIP was -53.5 cmH2O (range:-20 to -150 cmH2O); 71% of the patients maintained their MIP values below 70% of the predictive value. The differences found were not statistically significant. Conclusion Elderly patients admitted with AHF may present a high prevalence of RMW on admission; this condition may be maintained at similar levels on discharge in a large percentage of these patients, even after clinical stabilization of the heart condition. PMID:25671566

  17. Deleting exon 55 from the nebulin gene induces severe muscle weakness in a mouse model for nemaline myopathy.

    PubMed

    Ottenheijm, Coen A C; Buck, Danielle; de Winter, Josine M; Ferrara, Claudia; Piroddi, Nicoletta; Tesi, Chiara; Jasper, Jeffrey R; Malik, Fady I; Meng, Hui; Stienen, Ger J M; Beggs, Alan H; Labeit, Siegfried; Poggesi, Corrado; Lawlor, Michael W; Granzier, Henk

    2013-06-01

    Nebulin--a giant sarcomeric protein--plays a pivotal role in skeletal muscle contractility by specifying thin filament length and function. Although mutations in the gene encoding nebulin (NEB) are a frequent cause of nemaline myopathy, the most common non-dystrophic congenital myopathy, the mechanisms by which mutations in NEB cause muscle weakness remain largely unknown. To better understand these mechanisms, we have generated a mouse model in which Neb exon 55 is deleted (Neb(ΔExon55)) to replicate a founder mutation seen frequently in patients with nemaline myopathy with Ashkenazi Jewish heritage. Neb(ΔExon55) mice are born close to Mendelian ratios, but show growth retardation after birth. Electron microscopy studies show nemaline bodies--a hallmark feature of nemaline myopathy--in muscle fibres from Neb(ΔExon55) mice. Western blotting studies with nebulin-specific antibodies reveal reduced nebulin levels in muscle from Neb(ΔExon55) mice, and immunofluorescence confocal microscopy studies with tropomodulin antibodies and phalloidin reveal that thin filament length is significantly reduced. In line with reduced thin filament length, the maximal force generating capacity of permeabilized muscle fibres and single myofibrils is reduced in Neb(ΔExon55) mice with a more pronounced reduction at longer sarcomere lengths. Finally, in Neb(ΔExon55) mice the regulation of contraction is impaired, as evidenced by marked changes in crossbridge cycling kinetics and by a reduction of the calcium sensitivity of force generation. A novel drug that facilitates calcium binding to the thin filament significantly augmented the calcium sensitivity of submaximal force to levels that exceed those observed in untreated control muscle. In conclusion, we have characterized the first nebulin-based nemaline myopathy model, which recapitulates important features of the phenotype observed in patients harbouring this particular mutation, and which has severe muscle weakness caused by

  18. The weak link: do muscle properties determine locomotor performance in frogs?

    PubMed

    Roberts, Thomas J; Abbott, Emily M; Azizi, Emanuel

    2011-05-27

    Muscles power movement, yet the conceptual link between muscle performance and locomotor performance is poorly developed. Frog jumping provides an ideal system to probe the relationship between muscle capacity and locomotor performance, because a jump is a single discrete event and mechanical power output is a critical determinant of jump distance. We tested the hypothesis that interspecific variation in jump performance could be explained by variability in available muscle power. We used force plate ergometry to measure power produced during jumping in Cuban tree frogs (Osteopilus septentrionalis), leopard frogs (Rana pipiens) and cane toads (Bufo marinus). We also measured peak isotonic power output in isolated plantaris muscles for each species. As expected, jump performance varied widely. Osteopilus septentrionalis developed peak power outputs of 1047.0 ± 119.7 W kg(-1) hindlimb muscle mass, about five times that of B. marinus (198.5 ± 54.5 W kg(-1)). Values for R. pipiens were intermediate (543.9 ± 96.2 W kg(-1)). These differences in jump power were not matched by differences in available muscle power, which were 312.7 ± 28.9, 321.8 ± 48.5 and 262.8 ± 23.2 W kg(-1) muscle mass for O. septentrionalis, R. pipiens and B. marinus, respectively. The lack of correlation between available muscle power and jump power suggests that non-muscular mechanisms (e.g. elastic energy storage) can obscure the link between muscle mechanical performance and locomotor performance.

  19. The weak link: do muscle properties determine locomotor performance in frogs?

    PubMed Central

    Roberts, Thomas J.; Abbott, Emily M.; Azizi, Emanuel

    2011-01-01

    Muscles power movement, yet the conceptual link between muscle performance and locomotor performance is poorly developed. Frog jumping provides an ideal system to probe the relationship between muscle capacity and locomotor performance, because a jump is a single discrete event and mechanical power output is a critical determinant of jump distance. We tested the hypothesis that interspecific variation in jump performance could be explained by variability in available muscle power. We used force plate ergometry to measure power produced during jumping in Cuban tree frogs (Osteopilus septentrionalis), leopard frogs (Rana pipiens) and cane toads (Bufo marinus). We also measured peak isotonic power output in isolated plantaris muscles for each species. As expected, jump performance varied widely. Osteopilus septentrionalis developed peak power outputs of 1047.0 ± 119.7 W kg−1 hindlimb muscle mass, about five times that of B. marinus (198.5 ± 54.5 W kg−1). Values for R. pipiens were intermediate (543.9 ± 96.2 W kg−1). These differences in jump power were not matched by differences in available muscle power, which were 312.7 ± 28.9, 321.8 ± 48.5 and 262.8 ± 23.2 W kg−1 muscle mass for O. septentrionalis, R. pipiens and B. marinus, respectively. The lack of correlation between available muscle power and jump power suggests that non-muscular mechanisms (e.g. elastic energy storage) can obscure the link between muscle mechanical performance and locomotor performance. PMID:21502120

  20. [A 34-year-old woman with delayed motor milestones, high arched palate, and proximal muscle weakness].

    PubMed

    Yamamoto, T; Kitada, T; Hirasawa, E; Mori, H; Mizuno, Y

    1996-07-01

    We report a right-handed 34-year-old woman with diffuse muscle atrophy. The patient was a full-term infant of uneventful delivery, however, motor milestones were delayed in that neck control was obtained at 10 months of the age and she started to walk unassisted at 2 years of the age. Mental development was normal. She was unable to run with her mates at her kindergarten and she required a handrail when she walk up the stairs. She could not close her mouth completely at the primary school. She was unable to use a straw as a middle school pupil. Recently, she noted difficulty in raising her head from the supine position, and has become unable to walk a long distance. She was admitted to our hospital in September 17, 1994 when she was 34-year-old. On admission, general physical examination revealed that she looked slender weighing 38 kg with 149.5 cm height. She showed a high arched palate, slight scoliosis, and pes equinus. Otherwise general physical examination was unremarkable. Upon neurologic examination, she was alert and well oriented. Cranial nerves were unremarkable except for bilateral facial atrophy and moderate weakness. Her voice was of nasal quality, and swallowing was slightly difficult. No atrophy was noted in the sternocleidomastoid muscle. She showed waddling gait and positive Gowers' sign. Diffuse muscle atrophy was noted and mild to moderate weakness was presented more in the proximal part in both upper and lower extremities, however, deltoid muscles retained normal power. No ataxia was noted. All the deep tendon reflexes were lost. Sensation was intact. Routine laboratory examination was unremarkable. Serum CK was 56 IU/l. Electromyography revealed myogenic changes in the deltoid, biceps, and quadriceps muscles. A diagnostic biopsy was performed in the left biceps brachii muscle. The patient was discussed in the neurologic CPC, and the chief discussant arrived at the conclusion that the patient had nemaline myopathy. Opinions were divided among

  1. Actin filament organization and myosin head labelling patterns in vertebrate skeletal muscles in the rigor and weak binding states.

    PubMed

    Squire, J M; Harford, J J

    1988-08-01

    The structures of vertebrate skeletal muscles (particularly from frog and fish) in the rigor state are analysed in terms of the concept of target areas on actin filaments. Assuming that 100% of the heads are to be attached to actin in rigor, then satisfactory qualitative low-resolution modelling of observed X-ray diffraction data is obtained if the outer ends of these myosin heads can move axially (total range about 200A) and azimuthally (total range less than 60 degrees) from their original lattice sites on the myosin filament surface to attach in defined target areas on the actin filaments. On this basis, each actin target area comprises about four actin monomers along one of the two long-pitched helical strands of the actin filament (about 200 A) or an azimuthal range of actin binding sites of about 100 degrees around the thin filament axis. If myosin heads simply label in a non-specific way the nearest actin monomers to them, as could occur with non-specific transient attachment in a 'weak binding' state, then the predicted X-ray diffraction pattern would comprise layer lines at the same axial spacings (orders of 429 A) as those seen in patterns from resting muscle. It is shown that actin target areas in vertebrate skeletal muscles are probably arranged on an approximate 62 (right-handed) helix of pitch (P) of about 720 A, subunit translation P/6 and near repeat P/2. Troponin position need not be considered in defining the labelling pattern of cross-bridges on this 62 helix of target areas; the target areas appear to be defined solely by the azimuthal position of the actin binding sites. The distribution of actin filament labelling patterns could be regular in fish muscle which has a 'crystalline' A-band, but will be irregular in higher vertebrate muscles such as frog sartorius muscle.

  2. Induction of muscle weakness by local inflammation: an experimental animal model

    PubMed Central

    Bicer, S.; Reiser, P. J.; Ching, S.; Quan, N.

    2009-01-01

    Objective and design The objective of this study was to characterize the response of skeletal muscle to a localized inflammation induced by the inflammatory agent casein. Methods An inflammatory agent, casein, was injected into the right hindlimb and saline was injected into the left hindlimb of normal adult mice, once daily for six consecutive days. Inflammatory response was monitored by immunohistochemical labeling of leukocytes. Muscle protein levels were determined by electrophoresis and muscle function was determined by isometric force measurements. Results Local inflammation was induced by casein in association with the accumulation of extensive neutrophils and macrophages in the solues muscle. This local inflammation resulted in a shift in myosin heavy chain (MHC) isoform expression and a significant reduction in total MHC concentration in the soleus. Maximal twitch and tetanic forces were significantly reduced in the inflamed soleus. Contractile function in soleus was fully restored after two weeks of recovery, along with the restoration of protein concentration and the disappearance of inflammatory cells. Conclusion This study establishes a unique and robust model in which mechanisms of local inflammation induced muscle protein degradation, reduction of contractile force, and subsequent recovery from this condition can be further studied. PMID:19205846

  3. Plantaris muscle weakness in old mice: relative contributions of changes in specific force, muscle mass, myofiber cross-sectional area, and number.

    PubMed

    Ballak, Sam B; Degens, Hans; Busé-Pot, Tinelies; de Haan, Arnold; Jaspers, Richard T

    2014-01-01

    The age-related decline in muscle function contributes to the movement limitations in daily life in old age. The age-related loss in muscle force is attributable to loss of myofibers, myofiber atrophy, and a reduction in specific force. The contribution of each of these determinants to muscle weakness in old age is, however, largely unknown. The objective of this study is to determine whether a loss in myofiber number, myofiber atrophy, and a reduction in specific muscle force contribute to the age-related loss of muscle force in 25-month-old mouse. Maximal isometric force of in situ m. plantaris of C57BL/6J male adult (9 months) and old (25 months) mice was determined and related to myofiber number, myofiber size, intramuscular connective tissue content, and proportion of denervated myofibers. Isometric maximal plantaris muscle force was 13 % lower in old than adult mice (0.97 ± 0.05 N vs. 0.84 ± 0.03 N; P < 0.05). M. plantaris mass of old mice was not significantly smaller than that of adult mice. There was also no significant myofiber atrophy or myofiber loss. Specific muscle force of old mice was 25 % lower than that of adult mice (0.55 ± 0.05 vs. 0.41 ± 0.03 N·mm(-2), P < 0.01). In addition, with age, the proportion of type IIB myofibers decreased (43.6 vs. 38.4 %, respectively), while the connective tissue content increased (11.6 vs. 16.4 %, respectively). The age-related reduction in maximal isometric plantaris muscle force in 25-month-old male C57BL/6J mice is mainly attributable to a reduction in specific force, which is for 5 % explicable by an age-related increase in connective tissue, rather than myofiber atrophy and myofiber loss.

  4. Identification and Small Molecule Inhibition of an Activating Transcription Factor 4 (ATF4)-dependent Pathway to Age-related Skeletal Muscle Weakness and Atrophy*

    PubMed Central

    Ebert, Scott M.; Dyle, Michael C.; Bullard, Steven A.; Dierdorff, Jason M.; Murry, Daryl J.; Fox, Daniel K.; Bongers, Kale S.; Lira, Vitor A.; Meyerholz, David K.; Talley, John J.; Adams, Christopher M.

    2015-01-01

    Aging reduces skeletal muscle mass and strength, but the underlying molecular mechanisms remain elusive. Here, we used mouse models to investigate molecular mechanisms of age-related skeletal muscle weakness and atrophy as well as new potential interventions for these conditions. We identified two small molecules that significantly reduce age-related deficits in skeletal muscle strength, quality, and mass: ursolic acid (a pentacyclic triterpenoid found in apples) and tomatidine (a steroidal alkaloid derived from green tomatoes). Because small molecule inhibitors can sometimes provide mechanistic insight into disease processes, we used ursolic acid and tomatidine to investigate the pathogenesis of age-related muscle weakness and atrophy. We found that ursolic acid and tomatidine generate hundreds of small positive and negative changes in mRNA levels in aged skeletal muscle, and the mRNA expression signatures of the two compounds are remarkably similar. Interestingly, a subset of the mRNAs repressed by ursolic acid and tomatidine in aged muscle are positively regulated by activating transcription factor 4 (ATF4). Based on this finding, we investigated ATF4 as a potential mediator of age-related muscle weakness and atrophy. We found that a targeted reduction in skeletal muscle ATF4 expression reduces age-related deficits in skeletal muscle strength, quality, and mass, similar to ursolic acid and tomatidine. These results elucidate ATF4 as a critical mediator of age-related muscle weakness and atrophy. In addition, these results identify ursolic acid and tomatidine as potential agents and/or lead compounds for reducing ATF4 activity, weakness, and atrophy in aged skeletal muscle. PMID:26338703

  5. The effects of chest expansion resistance exercise on chest expansion and maximal respiratory pressure in elderly with inspiratory muscle weakness.

    PubMed

    Kim, Chang-Beom; Yang, Jin-Mo; Choi, Jong-Duk

    2015-04-01

    [Purpose] The aim of this study was to examine the effect of chest expansion resistance exercises (CERE) on chest expansion, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) in elderly people with inspiratory muscle weakness. [Subjects] Thirty elderly people with inspiratory muscle weakness (MIP < 80% of the predicted value) were randomly and equally assigned to a chest expansion resistance exercise (CERE) group, core conditioning exercise (CCE) group, and control group. [Methods] The intervention was applied to the CERE group and CCE group five times per week, 30 minutes each time, for six weeks. A tapeline was used to measure upper and lower chest expansion. MIP and MEP before and after the intervention were measured and compared. [Results] There was significant improvement in upper and lower chest expansion and MIP after the intervention in both the CERE group and the CCE group, whereas the control group did not show any significant difference. MEP did not significantly change in any of the three groups after the intervention. [Conclusion] The CERE group underwent greater changes than the CCE group, which proves that the CERE is more effective for improving elderly people's chest expansion capacity and MIP in elderly people. Therefore, application of the CERE by therapists is recommended if the environment and conditions are appropriate for enhancement of chest expansion capacity and MIP in elderly people.

  6. Altered cell metabolism in tissues of the knee joint in a rabbit model of Botulinum toxin A-induced quadriceps muscle weakness.

    PubMed

    Leumann, A; Longino, D; Fortuna, R; Leonard, T; Vaz, M A; Hart, D A; Herzog, W

    2012-12-01

    Quadriceps muscle weakness is frequently associated with knee injuries in sports. The influence of quadriceps weakness on knee joint homeostasis remains undefined. We hypothesized that quadriceps weakness will lead to tissue-specific alterations in the cell metabolism of tissues of the knee. Quadriceps weakness was induced with repetitive injections of Botulinum toxin A in six 1-year-old New Zealand White rabbits for 6 months. Five additional animals served as controls with injections of saline/dextrose. Muscle weakness was assessed by muscle wet mass, isometric knee extensor torque, and histological morphology analysis. Cell metabolism was assessed for patellar tendon, medial and lateral collateral ligament, and medial and lateral meniscus by measuring the total RNA levels and specific mRNA levels for collagen I, collagen III, MMP-1, MMP-3, MMP-13, TGF-β, biglycan, IL-1, and bFGF by reverse transcription and polymerase chain reaction. While the total RNA levels did not change, tissue-specific mRNA levels were lower for relevant anabolic and catabolic molecules, indicating potential changes in tissue mechanical set points. Quadriceps weakness may lead to adaptations in knee joint tissue cell metabolism by altering a subset of anabolic and catabolic mRNA levels corresponding to a new functional and metabolic set point for the knee that may contribute to the high injury rate of athletes with muscle weakness.

  7. Anatomy and function of the thenar muscles.

    PubMed

    Gupta, Salil; Michelsen-Jost, Heidi

    2012-02-01

    The four thenar muscles make up the intrinsic muscles of the thumb. They include the abductor pollicis, adductor pollicis, opponens pollicis, and flexor pollicis brevis. Thumb motion is facilitated through the coordination of these intrinsic muscles. The thumb musculature dynamically allows for precision pinching ad power gripping. PMID:22117918

  8. Structural characterization of weakly attached cross-bridges in the A*M*ATP state in permeabilized rabbit psoas muscle.

    PubMed Central

    Xu, S; Gu, J; Melvin, G; Yu, L C

    2002-01-01

    It is well established that in a skeletal muscle under relaxing conditions, cross-bridges exist in a mixture of four weak binding states in equilibrium (A*M*ATP, A*M*ADP*P(i), M*ATP, and M*ADP*P(i)). It has been shown that these four weak binding states are in the pathway to force generation. In the past their structural, biochemical, and mechanical properties have been characterized as a group. However, it was shown that the myosin heads in the M*ATP state exhibited a disordered distribution along the thick filament, while in the M*ADP*P(i) state they were well ordered. It follows that the structures of the weakly attached states of A*M*ATP and A*M*ADP*P(i) could well be different. Individual structures of the two attached states could not be assigned because protocol for isolating the two states has not been available until recently. In the present study, muscle fibers are reacted with N-phenylmaleimide such that ATP hydrolysis is inhibited, i.e., the cross-bridge population under relaxing conditions is distributed only between the two states of M*ATP and A*M*ATP. Two-dimensional x-ray diffraction was applied to determine the structural characteristics of the attached A*M*ATP state. Because the detached state of M*ATP is disordered and does not contribute to layer line intensities, changes as a result of increasing attachment in the A*M*ATP state are attributable to that state alone. The equilibrium toward the attached state was achieved by lowering the ionic strength. The results show that upon attachment, both the myosin and the first actin associated layer lines increased intensities, while the sixth actin layer line was not significantly affected. However, the intensities remain weak despite substantial attachment. The results, together with modeling (see J. Gu, S. Xu and L. C. Yu, 2002, Biophys. J. 82:2123-2133), suggest that there is a wide range of orientation of the attached A*M*ATP cross-bridges while the myosin heads maintain some degree of helical

  9. Anatomic study of the abductor pollicis longus: a source for grafting material of the hand.

    PubMed

    Bravo, Elena; Barco, Raul; Bullón, Adrian

    2010-05-01

    Interposition grafting material is used frequently to treat osteoarthritis of the base of the thumb or tendinous and ligamentous injuries of the hand. The observation of duplicated tendons in the first dorsal compartment of the hand prompted us to explore the possibility of using the accessory abductor pollicis longus (AAPL) tendon as grafting material. Based on dissections of 78 cadaveric upper limbs, we describe the number of tendons in the first dorsal compartment of the hand, the number of muscle bellies, their innervation, their insertion site, and the tendon dimensions to determine whether the AAPL can be considered a true tendon. The AAPL was present in 85% of the hands. Average length, width, and thickness (in millimeters) of the APL were of 69.3, 5.2, and 2.1, respectively. Average length, width, and thickness (in millimeters) of the AAPL were of 69.2, 3.3, and 1.6, respectively. No differences in dimension of the tendons were found between the APL and the AAPL. The dimensions of the tendinous portion of the AAPL are similar to those of the APL and can be considered a true tendon. When present, the AAPL is a suitable source of local grafting material.

  10. Anatomic Study of the Abductor Pollicis Longus: A Source for Grafting Material of the Hand

    PubMed Central

    Barco, Raul; Bullón, Adrian

    2009-01-01

    Interposition grafting material is used frequently to treat osteoarthritis of the base of the thumb or tendinous and ligamentous injuries of the hand. The observation of duplicated tendons in the first dorsal compartment of the hand prompted us to explore the possibility of using the accessory abductor pollicis longus (AAPL) tendon as grafting material. Based on dissections of 78 cadaveric upper limbs, we describe the number of tendons in the first dorsal compartment of the hand, the number of muscle bellies, their innervation, their insertion site, and the tendon dimensions to determine whether the AAPL can be considered a true tendon. The AAPL was present in 85% of the hands. Average length, width, and thickness (in millimeters) of the APL were of 69.3, 5.2, and 2.1, respectively. Average length, width, and thickness (in millimeters) of the AAPL were of 69.2, 3.3, and 1.6, respectively. No differences in dimension of the tendons were found between the APL and the AAPL. The dimensions of the tendinous portion of the AAPL are similar to those of the APL and can be considered a true tendon. When present, the AAPL is a suitable source of local grafting material. PMID:19760470

  11. A Comparison of Cough Assistance Techniques in Patients with Respiratory Muscle Weakness

    PubMed Central

    Kim, Sun Mi; Choi, Won Ah; Won, Yu Hui

    2016-01-01

    Purpose To assess the ability of a mechanical in-exsufflator (MI-E), either alone or in combination with manual thrust, to augment cough in patients with neuromuscular disease (NMD) and respiratory muscle dysfunction. Materials and Methods For this randomized crossover single-center controlled trial, patients with noninvasive ventilator-dependent NMD were recruited. The primary outcome was peak cough flow (PCF), which was measured in each patient after a cough that was unassisted, manually assisted following a maximum insufflation capacity (MIC) maneuver, assisted by MI-E, or assisted by manual thrust plus MI-E. The cough augmentation techniques were provided in random order. PCF was measured using a new device, the Cough Aid. Results All 40 enrolled participants (37 males, three females; average age, 20.9±7.2 years) completed the study. The mean (standard deviation) PCFs in the unassisted, manually assisted following an MIC maneuver, MI-E-assisted, and manual thrust plus MI-E-assisted conditions were 95.7 (40.5), 155.9 (53.1), 177.2 (33.9), and 202.4 (46.6) L/min, respectively. All three interventions significantly improved PCF. However, manual assistance following an MIC maneuver was significantly less effective than MI-E alone. Manual thrust plus MI-E was significantly more effective than both of these interventions. Conclusion In patients with NMD and respiratory muscle dysfunction, MI-E alone was more effective than manual assistance following an MIC maneuver. However, MI-E used in conjunction with manual thrust improved PCF even further. PMID:27593879

  12. Muscle Disorders

    MedlinePlus

    Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even ...

  13. Late-onset muscle weakness in partial phosphofructokinase deficiency: a unique myopathy with vacuoles, abnormal mitochondria, and absence of the common exon 5/intron 5 junction point mutation.

    PubMed

    Sivakumar, K; Vasconcelos, O; Goldfarb, L; Dalakas, M C

    1996-05-01

    Three patients (ages 51, 59, and 79) from two generations of an Ashkenazi Jewish family had partial (33% activity) phosphofructokinase (PFK) deficiency that presented with fixed muscle weakness after the age of 50 years. MR spectroscopy revealed accumulation of phosphomonoesters during exercise. Muscle biopsy showed a vacuolar myopathy with increased autophagic activity and several ragged-red and cytochrome c oxidase-negative fibers. The older patient, age 79 at biopsy, had several necrotic fibers. Electron microscopy revealed subsarcolemmal and intermyofibrillar glycogen accumulation and proliferation of mitochondria with paracrystalline inclusions, probably related to reduced availability of energy due to impaired glycolysis. The common point mutation of exon 5/intron 5 junction seen in Jewish Ashkenazi patients with PFK deficiency was excluded. We conclude that late-onset fixed muscle weakness occurs in partial PFK deficiency and it may represent the end result of continuing episodes of muscle fiber destruction. Partial enzyme deficiency in two successive generations suggests a unique molecular mechanism.

  14. Passive tension and stiffness of vertebrate skeletal and insect flight muscles: the contribution of weak cross-bridges and elastic filaments.

    PubMed Central

    Granzier, H L; Wang, K

    1993-01-01

    Tension and dynamic stiffness of passive rabbit psoas, rabbit semitendinosus, and waterbug indirect flight muscles were investigated to study the contribution of weak-binding cross-bridges and elastic filaments (titin and minititin) to the passive mechanical behavior of these muscles. Experimentally, a functional dissection of the relative contribution of actomyosin cross-bridges and titin and minititin was achieved by 1) comparing mechanically skinned muscle fibers before and after selective removal of actin filaments with a noncalcium-requiring gelsolin fragment (FX-45), and 2) studying passive tension and stiffness as a function of sarcomere length, ionic strength, temperature, and the inhibitory effect of a carboxyl-terminal fragment of smooth muscle caldesmon. Our data show that weak bridges exist in both rabbit skeletal muscle and insect flight muscle at physiological ionic strength and room temperature. In rabbit psoas fibers, weak bridge stiffness appears to vary with both thin-thick filament overlap and with the magnitude of passive tension. Plots of passive tension versus passive stiffness are multiphasic and strikingly similar for these three muscles of distinct sarcomere proportions and elastic proteins. The tension-stiffness plot appears to be a powerful tool in discerning changes in the mechanical behavior of the elastic filaments. The stress-strain and stiffness-strain curves of all three muscles can be merged into one, by normalizing strain rate and strain amplitude of the extensible segment of titin and minititin, further supporting the segmental extension model of resting tension development. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 PMID:8298040

  15. Massive accumulation of 11C-Pittsburg compound B in the occipital lobes of a patient with early-onset dementia accompanied by muscle weakness and hypertonicity.

    PubMed

    Ito, Kimiteru; Sano, Terunori; Kamiya, Kouhei; Nakata, Yasuhiro; Shigemoto, Yoko; Sato, Noriko; Oya, Yasushi; Matsuda, Hiroshi

    2013-12-01

    A 44-year-old woman underwent 11C-Pittsburg compound B (11C-PiB), 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT), 99mTc-ethyl-cysteinate-dimer single photon emission computed tomography, and magnetic resonance imaging after presenting with progressive dementia, muscle weakness, and hypertonicity. Some of her family members had died of muscle weakness with early-onset dementia of unknown etiology. Neurological and psychological examinations revealed moderate dementia in general fields and muscle weakness in her upper limbs. 11C-PiB PET/CT revealed abnormal accumulations of amyloid in the bilateral occipital lobes, while physiological uptakes of 11C-PiB in areas that normally show high uptake, such as white matter, appeared relatively decreased. Meanwhile, cerebrospinal fluid (CSF) amyloid-β was decreased, and CSF total and phosphorylated tau proteins were increased. This case may be representative of a new category of amyloid deposition disease characterized by early-onset dementia, muscle weakness, and hypertonicity, or at least, a new uptake pattern of PiB in variant AD.

  16. Abnormal actin binding of aberrant β-tropomyosins is a molecular cause of muscle weakness in TPM2-related nemaline and cap myopathy.

    PubMed

    Marttila, Minttu; Lemola, Elina; Wallefeld, William; Memo, Massimiliano; Donner, Kati; Laing, Nigel G; Marston, Steven; Grönholm, Mikaela; Wallgren-Pettersson, Carina

    2012-02-15

    NM (nemaline myopathy) is a rare genetic muscle disorder defined on the basis of muscle weakness and the presence of structural abnormalities in the muscle fibres, i.e. nemaline bodies. The related disorder cap myopathy is defined by cap-like structures located peripherally in the muscle fibres. Both disorders may be caused by mutations in the TPM2 gene encoding β-Tm (tropomyosin). Tm controls muscle contraction by inhibiting actin-myosin interaction in a calcium-sensitive manner. In the present study, we have investigated the pathogenetic mechanisms underlying five disease-causing mutations in Tm. We show that four of the mutations cause changes in affinity for actin, which may cause muscle weakness in these patients, whereas two show defective Ca2+ activation of contractility. We have also mapped the amino acids altered by the mutation to regions important for actin binding and note that two of the mutations cause altered protein conformation, which could account for impaired actin affinity. PMID:22084935

  17. Attempted reinnervation of the equine larynx using a muscle pedicle graft.

    PubMed

    Harrison, I W; Speirs, V C; Braund, K G; Steiss, J E

    1992-01-01

    Laryngeal hemiplegia was induced in 4 ponies via a left recurrent laryngeal neurectomy. Reinnervation of the denervated left cricoarytenoideus dorsalis muscle was then attempted using a muscle pedicle graft from the right cricoarytenoideus dorsalis muscle. In 3 ponies there was no return of abductor function and failure of graft survival. In the fourth pony there was return of abductor function along with survival of the muscle bridge, however, there was evidence of reinnervation across the neurectomy site. Muscle-to-muscle neurotization of the paralyzed equine larynx, utilizing the cricoarytenoideus dorsalis muscle, does not appear to be a clinically useful technique.

  18. Preferential denervation of the adductor muscles of the equine larynx. I: Muscle pathology.

    PubMed

    Duncan, I D; Amundson, J; Cuddon, P A; Sufit, R; Jackson, K F; Lindsay, W A

    1991-03-01

    The laryngeal muscles of 18 horses were examined histologically. The neurogenic changes found in each muscle were scored by four reviewers and the results evaluated statistically. Fifteen of these horses had endoscopic evidence of abnormal laryngeal function, three of which were defined as having adductor paralysis. Measurement of muscle fibre area in two horses with idiopathic laryngeal hemiplegia (ILH) was performed. In the quantitative study of neurogenic change, the adductor muscles were more significantly affected than the abductor muscle. This was also true in the clinical cases of ILH where measurement of muscle fibre area demonstrated that the lateral cricoarytenoid (adductor) muscles showed a wider range of pathological changes than the dorsal cricoarytenoid muscle (abductor). Those horses with the most severe muscle pathology also had the most abnormal endoscopic findings. The propensity for denervation of the adductor muscles should provide clues as to the pathogenesis and natural history of horses with sub-clinical laryngeal disease and ILH.

  19. An electrostatic model with weak actin-myosin attachment resolves problems with the lattice stability of skeletal muscle.

    PubMed

    Smith, D A; Stephenson, D G

    2011-06-01

    The stability of the filament lattice in relaxed striated muscle can be viewed as a balance of electrostatic and van der Waals forces. The simplest electrostatic model, where actin and myosin filaments are treated as charged cylinders, generates reasonable lattice spacings for skinned fibers. However, this model predicts excessive radial stiffness under osmotic pressure and cannot account for the initial pressure (∼1 kPa) required for significant compression. Good agreement with frog compression data is obtained with an extended model, in which S1 heads are weakly attached to actin when the lattice spacing is reduced below a critical value; further compression moves fixed negative charges on the heads closer to the myofilament backbone as they attach at a more acute angle to actin. The model predicts pH data in which the lattice shrinks as pH is lowered and protons bind to filaments. Electrostatic screening implies that the lattice shrinks with increasing ionic strength, but the observed expansion of the frog lattice at ionic strengths above 0.1 M with KCl might be explained if Cl(-) binds to sites on the motor domain of S1. With myosin-myosin and actin-actin interactions, the predicted lattice spacing decreases slightly with sarcomere length, with a more rapid decrease when actin-myosin filament overlap is very small. PMID:21641314

  20. Recurrent Muscle Weakness with Rhabdomyolysis, Metabolic Crises, and Cardiac Arrhythmia Due to Bi-allelic TANGO2 Mutations

    PubMed Central

    Lalani, Seema R.; Liu, Pengfei; Rosenfeld, Jill A.; Watkin, Levi B.; Chiang, Theodore; Leduc, Magalie S.; Zhu, Wenmiao; Ding, Yan; Pan, Shujuan; Vetrini, Francesco; Miyake, Christina Y.; Shinawi, Marwan; Gambin, Tomasz; Eldomery, Mohammad K.; Akdemir, Zeynep Hande Coban; Emrick, Lisa; Wilnai, Yael; Schelley, Susan; Koenig, Mary Kay; Memon, Nada; Farach, Laura S.; Coe, Bradley P.; Azamian, Mahshid; Hernandez, Patricia; Zapata, Gladys; Jhangiani, Shalini N.; Muzny, Donna M.; Lotze, Timothy; Clark, Gary; Wilfong, Angus; Northrup, Hope; Adesina, Adekunle; Bacino, Carlos A.; Scaglia, Fernando; Bonnen, Penelope E.; Crosson, Jane; Duis, Jessica; Maegawa, Gustavo H.B.; Coman, David; Inwood, Anita; McGill, Jim; Boerwinkle, Eric; Graham, Brett; Beaudet, Art; Eng, Christine M.; Hanchard, Neil A.; Xia, Fan; Orange, Jordan S.; Gibbs, Richard A.; Lupski, James R.; Yang, Yaping

    2016-01-01

    The underlying genetic etiology of rhabdomyolysis remains elusive in a significant fraction of individuals presenting with recurrent metabolic crises and muscle weakness. Using exome sequencing, we identified bi-allelic mutations in TANGO2 encoding transport and Golgi organization 2 homolog (Drosophila) in 12 subjects with episodic rhabdomyolysis, hypoglycemia, hyperammonemia, and susceptibility to life-threatening cardiac tachyarrhythmias. A recurrent homozygous c.460G>A (p.Gly154Arg) mutation was found in four unrelated individuals of Hispanic/Latino origin, and a homozygous ∼34 kb deletion affecting exons 3–9 was observed in two families of European ancestry. One individual of mixed Hispanic/European descent was found to be compound heterozygous for c.460G>A (p.Gly154Arg) and the deletion of exons 3–9. Additionally, a homozygous exons 4–6 deletion was identified in a consanguineous Middle Eastern Arab family. No homozygotes have been reported for these changes in control databases. Fibroblasts derived from a subject with the recurrent c.460G>A (p.Gly154Arg) mutation showed evidence of increased endoplasmic reticulum stress and a reduction in Golgi volume density in comparison to control. Our results show that the c.460G>A (p.Gly154Arg) mutation and the exons 3–9 heterozygous deletion in TANGO2 are recurrent pathogenic alleles present in the Latino/Hispanic and European populations, respectively, causing considerable morbidity in the homozygotes in these populations. PMID:26805781

  1. Recurrent Muscle Weakness with Rhabdomyolysis, Metabolic Crises, and Cardiac Arrhythmia Due to Bi-allelic TANGO2 Mutations.

    PubMed

    Lalani, Seema R; Liu, Pengfei; Rosenfeld, Jill A; Watkin, Levi B; Chiang, Theodore; Leduc, Magalie S; Zhu, Wenmiao; Ding, Yan; Pan, Shujuan; Vetrini, Francesco; Miyake, Christina Y; Shinawi, Marwan; Gambin, Tomasz; Eldomery, Mohammad K; Akdemir, Zeynep Hande Coban; Emrick, Lisa; Wilnai, Yael; Schelley, Susan; Koenig, Mary Kay; Memon, Nada; Farach, Laura S; Coe, Bradley P; Azamian, Mahshid; Hernandez, Patricia; Zapata, Gladys; Jhangiani, Shalini N; Muzny, Donna M; Lotze, Timothy; Clark, Gary; Wilfong, Angus; Northrup, Hope; Adesina, Adekunle; Bacino, Carlos A; Scaglia, Fernando; Bonnen, Penelope E; Crosson, Jane; Duis, Jessica; Maegawa, Gustavo H B; Coman, David; Inwood, Anita; McGill, Jim; Boerwinkle, Eric; Graham, Brett; Beaudet, Art; Eng, Christine M; Hanchard, Neil A; Xia, Fan; Orange, Jordan S; Gibbs, Richard A; Lupski, James R; Yang, Yaping

    2016-02-01

    The underlying genetic etiology of rhabdomyolysis remains elusive in a significant fraction of individuals presenting with recurrent metabolic crises and muscle weakness. Using exome sequencing, we identified bi-allelic mutations in TANGO2 encoding transport and Golgi organization 2 homolog (Drosophila) in 12 subjects with episodic rhabdomyolysis, hypoglycemia, hyperammonemia, and susceptibility to life-threatening cardiac tachyarrhythmias. A recurrent homozygous c.460G>A (p.Gly154Arg) mutation was found in four unrelated individuals of Hispanic/Latino origin, and a homozygous ∼34 kb deletion affecting exons 3-9 was observed in two families of European ancestry. One individual of mixed Hispanic/European descent was found to be compound heterozygous for c.460G>A (p.Gly154Arg) and the deletion of exons 3-9. Additionally, a homozygous exons 4-6 deletion was identified in a consanguineous Middle Eastern Arab family. No homozygotes have been reported for these changes in control databases. Fibroblasts derived from a subject with the recurrent c.460G>A (p.Gly154Arg) mutation showed evidence of increased endoplasmic reticulum stress and a reduction in Golgi volume density in comparison to control. Our results show that the c.460G>A (p.Gly154Arg) mutation and the exons 3-9 heterozygous deletion in TANGO2 are recurrent pathogenic alleles present in the Latino/Hispanic and European populations, respectively, causing considerable morbidity in the homozygotes in these populations.

  2. Anomalous abductor digiti minimi in Guyon canal: A cadaver study.

    PubMed

    Ciani, Mario James; LaFay, Vicki; Ciani, Gioia; Carey, Paul; Parnes, Nata

    2016-10-01

    A routine cadaver dissection revealed a noteworthy anomalous muscle in the distal anterior forearm. Clinicians should be aware of this finding and consider it as a differential diagnosis in patients with wrist disorders such as ulnar tunnel syndrome from occlusion of the ulnar canal. A space-occupying lesion, such as the anomalous muscle found in this dissection, is an important potential source of ulnar canal obstruction.

  3. Anomalous abductor digiti minimi in Guyon canal: A cadaver study.

    PubMed

    Ciani, Mario James; LaFay, Vicki; Ciani, Gioia; Carey, Paul; Parnes, Nata

    2016-10-01

    A routine cadaver dissection revealed a noteworthy anomalous muscle in the distal anterior forearm. Clinicians should be aware of this finding and consider it as a differential diagnosis in patients with wrist disorders such as ulnar tunnel syndrome from occlusion of the ulnar canal. A space-occupying lesion, such as the anomalous muscle found in this dissection, is an important potential source of ulnar canal obstruction. PMID:27685508

  4. [A case of neurologic muscle weakness, ataxia, and retinitis pigmentosa (NARP) syndrome with a novel mitochondrial mutation m.8729 G>A].

    PubMed

    Miyawaki, Toko; Koto, Shusuke; Ishihara, Hiroyuki; Goto, Yuichi; Nishino, Ichizo; Kanda, Fumio; Toda, Tatsushi

    2015-01-01

    We report a patient having classical clinical feature of neurologic muscle weakness, ataxia, and retinitis pigmentosa (NARP) and a novel mutation, m.8729 G>A in mitochondria DNA. The patient was referred to our hospital because of progressive ataxia in her limbs and trunk. She had a history of incapability of running long distances from childhood. Neurological examination revealed cerebellar ataxia, distal dominant muscle weakness in the limbs, hyporeflexia, hypoesthesia, myoclonus, sensorineural deafness, and retinitis pigmentosa. Magnetic resonance imaging (MRI) showed atrophy of brain stem and cerebellum as well as calcification of basal ganglia. In both serum and cerebrospinal fluid, lactate and pyruvate levels were elevated. Histological examination of biopsied muscle revealed chronic neurogenic changes without ragged red fibers. Genetic analysis of mitochondrial DNA (mtDNA) of the muscle revealed a heteroplasmic mutation, m.8729 G>A. Chemical analysis of the respiratory chain complexes in her muscle specimen demonstrated lower activities of complexes I and V. In our case, novel mutation of m.8729 G>A in mtDNA was indicated as the cause of NARP syndrome. PMID:25746071

  5. Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness

    PubMed Central

    Akca, Nezih; Ozdemir, Bulent; Kanat, Ayhan; Batcik, Osman Ersagun; Yazar, Ugur; Zorba, Orhan Unal

    2014-01-01

    Context: Little seems to be known about the sexual dysfunction (SD) in lumbar intervertebral disc herniation. Aims: Investigation of sexual and sphincter dysfunction in patient with lumbar disc hernitions. Settings and Design: A retrospective analysis. Materials and Methods: Sexual and sphincter dysfunction in patients admitted with lumbar disc herniations between September 2012-March 2014. Statistical Analysis Used: Statistical analysis was performed using the Predictive Analytics SoftWare (PASW) Statistics 18.0 for Windows (Statistical Package for the Social Sciences, SPSS Inc., Chicago, Illinois). The statistical significance was set at P < 0.05. The Wilcoxon signed ranks test was used to evaluate the difference between patients. Results: Four patients with sexual and sphincter dysfunction were found, including two women and two men, aged between 20 and 52 years. All of them admitted without low back pain. In addition, on neurological examination, reflex and motor deficit were not found. However, almost all patients had perianal sensory deficit and sexual and sphincter dysfunction. Magnetic resonance imaging (MRI) of three patients displayed a large extruded disc fragment at L5-S1 level on the left side. In fourth patient, there were not prominent disc herniations. There was not statistically significant difference between pre-operative and post-operative sexual function, anal-urethral sphincter function, and perianal sensation score. A syndrome in L5-S1 disc herniation with sexual and sphincter dysfunction without pain and muscle weakness was noted. We think that it is crucial for neurosurgeons to early realise that paralysis of the sphincter and sexual dysfunction are possible in patients with lumbar L5-S1 disc disease. Conclusion: A syndrome with perianal sensory deficit, paralysis of the sphincter, and sexual dysfunction may occur in patients with lumbar L5-S1 disc disease. The improvement of perianal sensory deficit after surgery was counteracted by a trend

  6. Early Life Exposure to Chronic Intermittent Hypoxia Primes Increased Susceptibility to Hypoxia-Induced Weakness in Rat Sternohyoid Muscle during Adulthood.

    PubMed

    McDonald, Fiona B; Dempsey, Eugene M; O'Halloran, Ken D

    2016-01-01

    Intermittent hypoxia is a feature of apnea of prematurity (AOP), chronic lung disease, and sleep apnea. Despite the clinical relevance, the long-term effects of hypoxic exposure in early life on respiratory control are not well defined. We recently reported that exposure to chronic intermittent hypoxia (CIH) during postnatal development (pCIH) causes upper airway muscle weakness in both sexes, which persists for several weeks. We sought to examine if there are persistent sex-dependent effects of pCIH on respiratory muscle function into adulthood and/or increased susceptibility to re-exposure to CIH in adulthood in animals previously exposed to CIH during postnatal development. We hypothesized that pCIH would cause long-lasting muscle impairment and increased susceptibility to subsequent hypoxia. Within 24 h of delivery, pups and their respective dams were exposed to CIH: 90 s of hypoxia reaching 5% O2 at nadir; once every 5 min, 8 h per day for 3 weeks. Sham groups were exposed to normoxia in parallel. Three groups were studied: sham; pCIH; and pCIH combined with adult CIH (p+aCIH), where a subset of the pCIH-exposed pups were re-exposed to the same CIH paradigm beginning at 13 weeks. Following gas exposures, sternohyoid and diaphragm muscle isometric contractile and endurance properties were examined ex vivo. There was no apparent lasting effect of pCIH on respiratory muscle function in adults. However, in both males and females, re-exposure to CIH in adulthood in pCIH-exposed animals caused sternohyoid (but not diaphragm) weakness. Exposure to this paradigm of CIH in adulthood alone had no effect on muscle function. Persistent susceptibility in pCIH-exposed airway dilator muscle to subsequent hypoxic insult may have implications for the control of airway patency in adult humans exposed to intermittent hypoxic stress during early life.

  7. Facial-muscle weakness, speech disorders and dysphagia are common in patients with classic infantile Pompe disease treated with enzyme therapy.

    PubMed

    van Gelder, C M; van Capelle, C I; Ebbink, B J; Moor-van Nugteren, I; van den Hout, J M P; Hakkesteegt, M M; van Doorn, P A; de Coo, I F M; Reuser, A J J; de Gier, H H W; van der Ploeg, A T

    2012-05-01

    Classic infantile Pompe disease is an inherited generalized glycogen storage disorder caused by deficiency of lysosomal acid α-glucosidase. If left untreated, patients die before one year of age. Although enzyme-replacement therapy (ERT) has significantly prolonged lifespan, it has also revealed new aspects of the disease. For up to 11 years, we investigated the frequency and consequences of facial-muscle weakness, speech disorders and dysphagia in long-term survivors. Sequential photographs were used to determine the timing and severity of facial-muscle weakness. Using standardized articulation tests and fibreoptic endoscopic evaluation of swallowing, we investigated speech and swallowing function in a subset of patients. This study included 11 patients with classic infantile Pompe disease. Median age at the start of ERT was 2.4 months (range 0.1-8.3 months), and median age at the end of the study was 4.3 years (range 7.7 months -12.2 years). All patients developed facial-muscle weakness before the age of 15 months. Speech was studied in four patients. Articulation was disordered, with hypernasal resonance and reduced speech intelligibility in all four. Swallowing function was studied in six patients, the most important findings being ineffective swallowing with residues of food (5/6), penetration or aspiration (3/6), and reduced pharyngeal and/or laryngeal sensibility (2/6). We conclude that facial-muscle weakness, speech disorders and dysphagia are common in long-term survivors receiving ERT for classic infantile Pompe disease. To improve speech and reduce the risk for aspiration, early treatment by a speech therapist and regular swallowing assessments are recommended.

  8. Loss of Tropomodulin4 in the zebrafish mutant träge causes cytoplasmic rod formation and muscle weakness reminiscent of nemaline myopathy.

    PubMed

    Berger, Joachim; Tarakci, Hakan; Berger, Silke; Li, Mei; Hall, Thomas E; Arner, Anders; Currie, Peter D

    2014-12-01

    Nemaline myopathy is an inherited muscle disease that is mainly diagnosed by the presence of nemaline rods in muscle biopsies. Of the nine genes associated with the disease, five encode components of striated muscle sarcomeres. In a genetic zebrafish screen, the mutant träge (trg) was isolated based on its reduction in muscle birefringence, indicating muscle damage. Myofibres in trg appeared disorganised and showed inhomogeneous cytoplasmic eosin staining alongside malformed nuclei. Linkage analysis of trg combined with sequencing identified a nonsense mutation in tropomodulin4 (tmod4), a regulator of thin filament length and stability. Accordingly, although actin monomers polymerize to form thin filaments in the skeletal muscle of tmod4(trg) mutants, thin filaments often appeared to be dispersed throughout myofibres. Organised myofibrils with the typical striation rarely assemble, leading to severe muscle weakness, impaired locomotion and early death. Myofibrils of tmod4(trg) mutants often featured thin filaments of various lengths, widened Z-disks, undefined H-zones and electron-dense aggregations of various shapes and sizes. Importantly, Gomori trichrome staining and the lattice pattern of the detected cytoplasmic rods, together with the reactivity of rods with phalloidin and an antibody against actinin, is reminiscent of nemaline rods found in nemaline myopathy, suggesting that misregulation of thin filament length causes cytoplasmic rod formation in tmod4(trg) mutants. Although Tropomodulin4 has not been associated with myopathy, the results presented here implicateTMOD4 as a novel candidate for unresolved nemaline myopathies and suggest that the tmod4(trg) mutant will be a valuable tool to study human muscle disorders. PMID:25288681

  9. Laser Posterior Cordotomy: Is it a Good Choice in Treating Bilateral Vocal Fold Abductor Paralysis?

    PubMed Central

    Khalil, Mahmoud A; Abdel Tawab, Hazem M

    2014-01-01

    BACKGROUND Bilateral abductor vocal fold paralysis can lead to respiratory distress and dyspnea. OBJECTIVES To assess the efficacy of CO2 laser unilateral posterior cordotomy in cases with bilateral abductor paralysis as regards improvement of dyspnea with preservation of satisfactory voice and swallowing after the operation. METHODS A prospective study was done on 18 patients with bilateral abductor vocal fold paralysis (10 females and 8 males) from November 2010 to December 2012 with their ages ranging from 32 to 64 years. RESULTS All patients showed improvement of dyspnea after the operation, most of the patients suffered from mild to moderate dyspnea in the immediate post-operative period, and two patients needed another intervention to solve it. All the patients had satisfactory results of their voice after the operation, and one patient only suffered from temporary aspiration. CONCLUSION Unilateral CO2 laser posterior cordotomy is an easy and effective procedure to solve the dyspnea after bilateral vocal fold abductor paralysis without aspiration or significant voice alteration. PMID:25057244

  10. De Quervain disease caused by abductor pollicis longus tenosynovitis: a report of three cases.

    PubMed

    Maruyama, Masahiro; Takahara, Masatoshi; Kikuchi, Noriaki; Ito, Kazuo; Watanabe, Tadayoshi; Ogino, Toshihiko

    2009-01-01

    De Quervain disease is caused by a stenosing tenosynovitis in the first dorsal compartment, and the main aetiology is extensor pollicis brevis (EPB) tenosynovitis. We encountered three cases in which EPB tenosynovitis was absent and abductor pollicis longus (APL) tenosynovitis was confirmed during operation. In the treatment of de Quervain disease, APL tenosynovitis should be paid as much attention as EPB tenosynovitis. PMID:19598322

  11. Muscle weakness in TPM3-myopathy is due to reduced Ca2+-sensitivity and impaired acto-myosin cross-bridge cycling in slow fibres.

    PubMed

    Yuen, Michaela; Cooper, Sandra T; Marston, Steve B; Nowak, Kristen J; McNamara, Elyshia; Mokbel, Nancy; Ilkovski, Biljana; Ravenscroft, Gianina; Rendu, John; de Winter, Josine M; Klinge, Lars; Beggs, Alan H; North, Kathryn N; Ottenheijm, Coen A C; Clarke, Nigel F

    2015-11-15

    Dominant mutations in TPM3, encoding α-tropomyosinslow, cause a congenital myopathy characterized by generalized muscle weakness. Here, we used a multidisciplinary approach to investigate the mechanism of muscle dysfunction in 12 TPM3-myopathy patients. We confirm that slow myofibre hypotrophy is a diagnostic hallmark of TPM3-myopathy, and is commonly accompanied by skewing of fibre-type ratios (either slow or fast fibre predominance). Patient muscle contained normal ratios of the three tropomyosin isoforms and normal fibre-type expression of myosins and troponins. Using 2D-PAGE, we demonstrate that mutant α-tropomyosinslow was expressed, suggesting muscle dysfunction is due to a dominant-negative effect of mutant protein on muscle contraction. Molecular modelling suggested mutant α-tropomyosinslow likely impacts actin-tropomyosin interactions and, indeed, co-sedimentation assays showed reduced binding of mutant α-tropomyosinslow (R168C) to filamentous actin. Single fibre contractility studies of patient myofibres revealed marked slow myofibre specific abnormalities. At saturating [Ca(2+)] (pCa 4.5), patient slow fibres produced only 63% of the contractile force produced in control slow fibres and had reduced acto-myosin cross-bridge cycling kinetics. Importantly, due to reduced Ca(2+)-sensitivity, at sub-saturating [Ca(2+)] (pCa 6, levels typically released during in vivo contraction) patient slow fibres produced only 26% of the force generated by control slow fibres. Thus, weakness in TPM3-myopathy patients can be directly attributed to reduced slow fibre force at physiological [Ca(2+)], and impaired acto-myosin cross-bridge cycling kinetics. Fast myofibres are spared; however, they appear to be unable to compensate for slow fibre dysfunction. Abnormal Ca(2+)-sensitivity in TPM3-myopathy patients suggests Ca(2+)-sensitizing drugs may represent a useful treatment for this condition.

  12. [WEAK COMBINED MAGNETIC FIELDS ADJUSTED TO THE PARAMETRIC RESONANCE FOR Ca2+ INTENSIFY DYSTROPHIN SYNTHESIS IN MDX MICE SKELETAL MUSCLES AFTER CELL THERAPY].

    PubMed

    Sokolova, A V; Sokolov, G V; Mikhailov, V M

    2016-01-01

    The mdx mice are an X-linked myopathic mutants, an animal model for human Duchenne muscular dystrophy (DMD). Mdx mice muscles are characterized by high level of striated muscle fibers (SMF) death followed by regeneration. As a result most SMFs of mdx mice have centrally located nuclei. The possibility of using stem cells therapy for the correction of DMD is actively being studied. One of the approaches to the usage of bone marrow stem cells for cellular therapy of DMD is the replacement of bone marrow after irradiation by X-rays. This method however does not give significant increase of dystrophin synthesis in mdx mice muscles fibers. We have tried to affect the mice after bone marrow transplantation by weak combined magnetic fields adjusted to the parametric resonance for Ca2+(Ca(2+)-MF) based on the data that the weak combined magnetic fields influence on tissues regeneration. We observed a significant increase in the proportion of dystrophin-positive SMFs in group of mdx mice radiation chimera 5 Gy and 3 Gy which was additionally exposed in Ca(2+)-MF in comparison with the control mdx mice and the group of mdx mice radiation chimera 5 Gy and 3 Gy which was kept in terrestrial magnetic field 2 months after chimera preparation--up to 15.8 and 18.3%, respectively. Also, there was an accumulation of SMFs without central nuclei. These data indicate a significanly increased efficacy of cell therapy in the case of additional exposition in Ca(2+)-MF. Thus, the efficiency of bone marrow transplantation mdx mice after both in doses 3 and 5 Gy was considerably enhanced by additional exposition to Ca(2+)-MF. Apparently, such magnetic field can intensify functioning of donor's nuclei which had been incorporated into muscle fibers. PMID:27228662

  13. Isokinetic Testing of the Shoulder Abductors and Adductors: Windowed vs Nonwindowed Data Collection.

    PubMed

    Wilk, K E; Arrigo, C A; Andrews, J R

    1992-01-01

    Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1991, New Orleans, LA The manner of acquiring strength-testing data may influence the results of an investigation. The purpose of this study was to determine if a significant difference exists between windowed and unwindowed data collection during isokinetic testing of the shoulder abductors/adductors. Fifty healthy professional baseball pitchers participated in this study. Testing was performed on a Biodex isokinetic dynamometer at 180 and 300 degrees /sec for both the throwing and nonthrowing shoulders. Testing procedures regarding testing protocol, repetitions, positioning, and stabilization followed established guidelines for each subject. Statistical analysis was performed using a paired t-test with a p < 0.01 level of significance. Statistically significant differences were demonstrated between windowed and unwindowed mean peak torque data for both shoulders at both test speeds. The results indicated an average nonthrowing arm difference of 20.2 ft/lbs at 180 degrees /sec and 51.7 ft/lbs at 300 degrees / sec for the abductors. In each instance, the unwindowed mean peak torque values were higher than the windowed values, and significant end range torque spikes were elicited during unwindowed data collection. The nonthrowing adductors exhibited an average of 39.3 and 48.3 ft/lb differences at 180 and 300 degrees /sec, respectively. The throwing shoulder demonstrated average abductor differences of 25.6 ft/lbs at 180 degrees /sec and 47.7 ft/lbs at 300 degrees /sec. The average throwing adductor difference was 24.4 ft/lbs and 54.6 ft/lbs, respectively, at both test speeds. This investigation offers clinical relevance for those using isokinetic testing of the shoulder abductors/adductors in demonstrating the significant differences between windowed and unwindowed data, identifying torque spike data misinterpretation, and describing a clinical means of controlling aberrant torque

  14. Effects of Compliance on Trunk and Hip Integrative Neuromuscular Training on Hip Abductor Strength in Female Athletes

    PubMed Central

    SUGIMOTO, DAI; MYER, GREGORY D.; BUSH, HEATHER M.; HEWETT, TIMOTHY E.

    2014-01-01

    Sugimoto, D, Myer, GD, Bush, HM, and Hewett, TE. Effects of compliance on trunk and hip integrative neuromuscular training on hip abductor strength in female athletes. Recent studies demonstrate the link between reduced hip abductor strength and increased risk for knee injury such as patellofemoral pain syndrome in women athletes. Meta-analytic reports indicate that the efficacy of integrative neuromuscular training (INT) is associated with compliance to the prescribed programming. Thus, the purpose was to investigate the compliance effects of a trunk and hip–focused INT exercises on hip abductor strength in young women athletes. In a controlled laboratory study design, 21 high school women volleyball players (mean age = 15.6 ± 1.4 years, weight = 64.0 ± 7.4 kg, height = 171.5 ± 7.0 cm) completed isokinetic hip abductor strength testing in pre- and postintervention, which consisted of 5 phases of supervised progressive trunk and hip–focused INT exercises twice a week for 10 weeks. The compliance effects were analyzed based on the changed hip abductor strength values between pre- and postintervention and 3 different compliance groups using 1-way analysis of variance and Pearson’s correlation coefficients. The participants in the high-compliance group demonstrated significant hip abductor peak torque increases compared with noncompliance group (p = 0.02), but not between moderate-compliance and noncompliance groups (p = 0.27). The moderate correlation coefficient value (r = 0.56) was recorded between the isokinetic hip abductor peak torque changes and the 3 compliance groups. Because of the observed significant effects and moderate linear association, the effectiveness of a trunk and hip–focused INT protocol to improve hip abduction strength seems dependent on compliance. Compliance of trunk and hip–focused INT is an important aspect of increasing hip abductor strength increase in young women athletes. PMID:24751656

  15. Contribution of direct actions of the oxime HI-6 in reversing soman-induced muscle weakness in the rat diaphragm.

    PubMed

    Adler, M; Maxwell, D M; Filbert, M G; Deshpande, S S

    1994-01-01

    The actions of the bispyridinium oxime HI-6 ([[[(4-aminocarbonyl)pyridino]-methoxy]methyl]-2- [(hydroxyimino)methyl]-pyridinium dichloride) were investigated in vitro on rat phrenic nerve-hemidiaphragm preparations. Isometric twitch and tetanic tensions were elicited at 37 degrees C with supramaximal nerve stimulation at frequencies of 20 and 50 Hz. To approximate normal respiration patterns, trials consisting of 30 successive 0.55 s trains were alternated with 1.25 s rest periods. Under control conditions, the above stimulation pattern generated tensions that were well maintained at both frequencies. In contrast, a marked depression of muscle tension was observed in diaphragms removed from rats administered 339 micrograms/kg soman (3 LD50) and tested in vitro. Addition of HI-6, 4 h after soman exposure, led to a nearly complete recovery of muscle tension at 20 Hz. At 50 Hz, muscle tensions still declined especially when trains were elicited at 1.25 and 3 s intervals. The recovery by HI-6 observed in this study appears to be mediated by mechanisms unrelated to acetylcholinesterase reactivation since no increase of enzymatic activity was detected and the effect was reversed by a brief washout in oxime-free physiological solution. The results suggest that the direct action of HI-6 may play a role in restoring soman-induced diaphragmatic failure but this effect would be significant primarily under low use conditions. PMID:8157086

  16. Postoperative gait analysis and hip muscle strength in patients with pelvic ring fracture.

    PubMed

    Kubota, Masafumi; Uchida, Kenzo; Kokubo, Yasuo; Shimada, Seiichiro; Matsuo, Hideaki; Yayama, Takafumi; Miyazaki, Tsuyoshi; Sugita, Daisuke; Watanabe, Shuji; Baba, Hisatoshi

    2013-07-01

    The aims of present study were (1) to determine changes in kinematic and kinetic variables at 3 and 12 months after open reduction and internal fixation (ORIF) of pelvic ring fracture and (2) to determine the factor(s) associated with gait disorders that correlate with gait parameters measured at 12 months after surgery. Nineteen patients with pelvic ring fractures underwent ORIF and examined at 3 and 12 months postoperatively. The study also included a similar number of age-matched control subjects. Peak hip abduction angle, peak hip extension moment in the stance, peak hip abduction moment, and peak ankle plantarflexion moment at 3 months after ORIF were significantly lower than the respective control values. At 12 months, complete recovery was noted in peak hip abduction moment and peak ankle plantarflexion moment, whereas the recovery in peak hip abduction angle and peak hip extension moment in the stance was partial. The existence of neurological lesions and strength asymmetry of hip abductor and adductor at 3 months post-ORIF correlated with decreased peak hip abduction moment after ORIF. Our results highlighted characteristic gait patterns up to 12 months after ORIF for pelvic fracture, and these patterns correlated with neurological lesion and weakness of hip abductor and adductor muscles. PMID:23333355

  17. FE65 and FE65L1 amyloid precursor protein–binding protein compound null mice display adult-onset cataract and muscle weakness

    PubMed Central

    Suh, Jaehong; Moncaster, Juliet A.; Wang, Lirong; Hafeez, Imran; Herz, Joachim; Tanzi, Rudolph E.; Goldstein, Lee E.; Guénette, Suzanne Y.

    2015-01-01

    FE65 and FE65L1 are cytoplasmic adaptor proteins that bind a variety of proteins, including the amyloid precursor protein, and that mediate the assembly of multimolecular complexes. We previously reported that FE65/FE65L1 double knockout (DKO) mice display disorganized laminin in meningeal fibroblasts and a cobblestone lissencephaly-like phenotype in the developing cortex. Here, we examined whether loss of FE65 and FE65L1 causes ocular and muscular deficits, 2 phenotypes that frequently accompany cobblestone lissencephaly. Eyes of FE65/FE65L1 DKO mice develop normally, but lens degeneration becomes apparent in young adult mice. Abnormal lens epithelial cell migration, widespread small vacuole formation, and increased laminin expression underneath lens capsules suggest impaired interaction between epithelial cells and capsular extracellular matrix in DKO lenses. Cortical cataracts develop in FE65L1 knockout (KO) mice aged 16 months or more but are absent in wild-type or FE65 KO mice. FE65 family KO mice show attenuated grip strength, and the nuclei of DKO muscle cells frequently locate in the middle of muscle fibers. These findings reveal that FE65 and FE65L1 are essential for the maintenance of lens transparency, and their loss produce phenotypes in brain, eye, and muscle that are comparable to the clinical features of congenital muscular dystrophies in humans.—Suh, J., Moncaster, J. A., Wang, L., Hafeez, I., Herz, J., Tanzi, R. E., Goldstein, L. E., Guénette, S. Y. FE65 and FE65L1 amyloid precursor protein–binding protein compound null mice display adult-onset cataract and muscle weakness. PMID:25757569

  18. Effects of compliance on trunk and hip integrative neuromuscular training on hip abductor strength in female athletes.

    PubMed

    Sugimoto, Dai; Myer, Gregory D; Bush, Heather M; Hewett, Timothy E

    2014-05-01

    Recent studies demonstrate the link between reduced hip abductor strength and increased risk for knee injury such as patellofemoral pain syndrome in women athletes. Meta-analytic reports indicate that the efficacy of integrative neuromuscular training (INT) is associated with compliance to the prescribed programming. Thus, the purpose was to investigate the compliance effects of a trunk and hip-focused INT exercises on hip abductor strength in young women athletes. In a controlled laboratory study design, 21 high school women volleyball players (mean age = 15.6 ± 1.4 years, weight = 64.0 ± 7.4 kg, height = 171.5 ± 7.0 cm) completed isokinetic hip abductor strength testing in pre- and postintervention, which consisted of 5 phases of supervised progressive trunk and hip-focused INT exercises twice a week for 10 weeks. The compliance effects were analyzed based on the changed hip abductor strength values between pre- and postintervention and 3 different compliance groups using 1-way analysis of variance and Pearson's correlation coefficients. The participants in the high-compliance group demonstrated significant hip abductor peak torque increases compared with noncompliance group (p = 0.02), but not between moderate-compliance and noncompliance groups (p = 0.27). The moderate correlation coefficient value (r = 0.56) was recorded between the isokinetic hip abductor peak torque changes and the 3 compliance groups. Because of the observed significant effects and moderate linear association, the effectiveness of a trunk and hip-focused INT protocol to improve hip abduction strength seems dependent on compliance. Compliance of trunk and hip-focused INT is an important aspect of increasing hip abductor strength increase in young women athletes. PMID:24751656

  19. Hand weakness in Charcot-Marie-Tooth disease 1X.

    PubMed

    Arthur-Farraj, P J; Murphy, S M; Laura, M; Lunn, M P; Manji, H; Blake, J; Ramdharry, G; Fox, Z; Reilly, M M

    2012-07-01

    There have been suggestions from previous studies that patients with Charcot-Marie-Tooth disease (CMT) have weaker dominant hand muscles. Since all studies to date have included a heterogeneous group of CMT patients we decided to analyse hand strength in 43 patients with CMT1X. We recorded handedness and the MRC scores for the first dorsal interosseous and abductor pollicis brevis muscles, median and ulnar nerve compound motor action potentials and conduction velocities in dominant and non-dominant hands. Twenty-two CMT1X patients (51%) had a weaker dominant hand; none had a stronger dominant hand. Mean MRC scores were significantly higher for first dorsal interosseous and abductor pollicis brevis in non-dominant hands compared to dominant hands. Median nerve compound motor action potentials were significantly reduced in dominant compared to non-dominant hands. We conclude that the dominant hand is weaker than the non-dominant hand in patients with CMT1X.

  20. Hand weakness in Charcot-Marie-Tooth disease 1X

    PubMed Central

    Arthur-Farraj, P.J.; Murphy, S.M.; Laura, M.; Lunn, M.P.; Manji, H.; Blake, J.; Ramdharry, G.; Fox, Z.; Reilly, M.M.

    2012-01-01

    There have been suggestions from previous studies that patients with Charcot–Marie–Tooth disease (CMT) have weaker dominant hand muscles. Since all studies to date have included a heterogeneous group of CMT patients we decided to analyse hand strength in 43 patients with CMT1X. We recorded handedness and the MRC scores for the first dorsal interosseous and abductor pollicis brevis muscles, median and ulnar nerve compound motor action potentials and conduction velocities in dominant and non-dominant hands. Twenty-two CMT1X patients (51%) had a weaker dominant hand; none had a stronger dominant hand. Mean MRC scores were significantly higher for first dorsal interosseous and abductor pollicis brevis in non-dominant hands compared to dominant hands. Median nerve compound motor action potentials were significantly reduced in dominant compared to non-dominant hands. We conclude that the dominant hand is weaker than the non-dominant hand in patients with CMT1X. PMID:22464564

  1. Intellectual disability, muscle weakness and characteristic face in three siblings: A newly described recessive syndrome mapping to 3p24.3-p25.3.

    PubMed

    Kariminejad, Ariana; Nafissi, Shahriar; Nilipoor, Yalda; Tavasoli, Alireza; Van Veldhoven, Paul P; Bonnard, Carine; Ng, Yeng Ting; Majoie, Charles B; Reversade, Bruno; Hennekam, Raoul C

    2015-11-01

    We report on a sister and two brothers born to healthy Iranian parents with mild intellectual disability, progressive muscle weakness, and characteristic facies. including highly arched eyebrows, down-slanting palpebral fissures, prominent nasal bridge, prominent nose, columella extending below alae nasi, narrow mouth, narrow palate, and dental caries, and in one of them an inability to abduct the left eye. Electrophysiological studies showed signs of myopathy, and muscle biopsies demonstrated only nonspecific signs. Brain MRIs in two of the sibs showed leukencephalopathy with delayed myelination, frontal and parietal hyperintensities, and hippocampal atrophy in one. We have been unable to find a description of this association of features in literature. Based on the occurrence in siblings, no significant difference in phenotype between the brothers and sister, absence of manifestations in parents, and a likely consanguinity between parents we performed a homozygosity mapping. A single identical-by-descent bloc encompassing 57 genes located at 3p24.3-p25.3 was found to segregate within the family with this phenotype. © 2015 Wiley Periodicals, Inc.

  2. Both poor cardiorespiratory and weak muscle fitness are related to a high concentration of oxidized low-density lipoprotein lipids.

    PubMed

    Kosola, J; Ahotupa, M; Kyröläinen, H; Santtila, M; Vasankari, T

    2012-12-01

    Good physical fitness is associated with favorable serum lipids. Oxidized low-density lipoprotein (ox-LDL) could be even more atherogenic than serum lipids. We studied the association of ox-LDL and serum lipids with physical fitness. Healthy young (mean age 25 years) men (n=846) underwent maximal oxygen uptake (VO(2max)) and muscle fitness index (MFI) tests and completed a leisure-time physical activity (LTPA) questionnaire. Age (ANCOVA1), age+waist circumference+systolic blood pressure+fasting blood glucose+smoking (ANCOVA3) were used as covariates. The groups with the lowest VO(2max), MFI and LTPA had 23%, 16% and 8% higher concentrations of ox-LDL than the groups with the highest VO(2max) (P<0.0001), MFI (P=0.022) and LTPA (P=0.039) groups, respectively. Subjects with poor fitness (low VO(2max) or low MFI) or low LTPA had elevated levels of ox-LDL/high-density lipoprotein (HDL)-cholesterol, total cholesterol, LDL-cholesterol, triglycerides and a low level of HDL-cholesterol (ANCOVA1, in all, P<0.05). Furthermore, low VO(2max) is associated with a high level of ox-LDL/HDL-cholesterol and triglycerides, and with a low level of HDL-cholesterol (ANCOVA3, in all, P<0.05). Also, subjects with low LTPA had a high ratio of ox-LDL/HDL-cholesterol (ANCOVA1, P=0.001). In conclusion, both poor fitness (both low VO(2max) and low MFI) and low LTPA are associated with a higher concentration of ox-LDL lipids and serum lipids, which may indicate a higher risk for atherosclerosis.

  3. Abductor pollicis longus "hammock" ligamentoplasty for treatment of first carpometacarpal arthritis.

    PubMed

    Mathoulin, C; Moreel, P; Costa, R; Wilson, S M

    2008-06-01

    The association of trapeziectomy with ligamentoplasty is a simple treatment for osteoarthritis at the base of the thumb. Here we present the long-term results of a technique that creates a "hammock" under the first metacarpal bone using the Abductor Pollicis Longus tendon. This paper reports the results of treatment by this operation of 60 thumbs in 50 patients, including 13 men and 37 women of average age 60 (46-75) years. Thirty thumbs presented with severe pain and 30 with moderate pain. At final follow-up, 47 thumbs (78%) had experienced dramatic relief of pain following the procedure, 12 (20%) thumbs still had mild pain and one (2%) thumb had severe pain. No patients needed revision.

  4. Exercising with a Muscle Disease

    MedlinePlus

    ... are: • cramping in muscles (probably related to insufficient energy supply for muscles) • pain in musclesweakness of exercised muscles • dark urine that looks like cola, following exercise (seek ...

  5. EMG feedback as a muscle reeducation technique: a controlled study.

    PubMed

    Middaugh, S J

    1978-01-01

    In an effort to evaluate the efficacy and function of EMG feedback in muscle reeducation, improvement of the abductor function of the abductor hallucis muscle was studied under three training conditions involving 1) EMG feedback, 2) sensory stimulation or 3) equal time for unassisted practice; and a fourth, control condition involving testing without training. Active range of motion was measured before and after training to assess ability to use the muscle as an abductor. EMG activity was quantified for a 1-minute test contraction to evaluate ability to maintain and maximize a voluntary contraction of the target muscle. The results indicated that EMG feedback was highly effective when subjects had little initial use of the target muscle. EMG feedback improved the ability of these subjects to maintain and maximize voluntary muscle contractions, as demonstrated on the EMG measure. EMG feedback did not add to the learning situation when only a relatively brief, phasic contraction was required, as on the range-of-motion measure; similar gains were made with equivalent practive without EMG feedback. When subjects already had considerable use of the target muscle prior to training, EMG feedback may have actually interfered with training; in this case unassisted practice was more effective.

  6. Novel excitation-contraction coupling related genes reveal aspects of muscle weakness beyond atrophy—new hopes for treatment of musculoskeletal diseases

    PubMed Central

    Manring, Heather; Abreu, Eduardo; Brotto, Leticia; Weisleder, Noah; Brotto, Marco

    2013-01-01

    Research over the last decade strengthened the understanding that skeletal muscles are not only the major tissue in the body from a volume point of view but also function as a master regulator contributing to optimal organismal health. These new contributions to the available body of knowledge triggered great interest in the roles of skeletal muscle beyond contraction. The World Health Organization, through its Global Burden of Disease (GBD) report, recently raised further awareness about the key importance of skeletal muscles as the GDB reported musculoskeletal (MSK) diseases have become the second greatest cause of disability, with more than 1.7 billion people in the globe affected by a diversity of MSK conditions. Besides their role in MSK disorders, skeletal muscles are also seen as principal metabolic organs with essential contributions to metabolic disorders, especially those linked to physical inactivity. In this review, we have focused on the unique function of new genes/proteins (i.e., MTMR14, MG29, sarcalumenin, KLF15) that during the last few years have helped provide novel insights about muscle function in health and disease, muscle fatigue, muscle metabolism, and muscle aging. Next, we provide an in depth discussion of how these genes/proteins converge into a common function of acting as regulators of intracellular calcium homeostasis. A clear link between dysfunctional calcium homeostasis is established and the special role of store-operated calcium entry is analyzed. The new knowledge that has been generated by the understanding of the roles of previously unknown modulatory genes of the skeletal muscle excitation-contraction coupling (ECC) process brings exciting new possibilities for treatment of MSK diseases, muscle regeneration, and skeletal muscle tissue engineering. The next decade of skeletal muscle and MSK research is bound to bring to fruition applied knowledge that will hopefully offset the current heavy and sad burden of MSK diseases on the

  7. Inter-Tester Reliability and Precision of Manual Muscle Testing and Hand-Held Dynamometry in Lower Limb Muscles of Children with Spina Bifida

    ERIC Educational Resources Information Center

    Mahony, Kate; Hunt, Adrienne; Daley, Deborah; Sims, Susan; Adams, Roger

    2009-01-01

    Reliability and measurement precision of manual muscle testing (MMT) and hand-held dynamometry (HHD) were compared for children with spina bifida. Strength measures were obtained of the hip flexors, hip abductors, and knee extensors of 20 children (10 males, 10 females; mean age 9 years 10 months; range: 5 to 15 years) by two experienced physical…

  8. Anatomical variation of abductor pollicis longus in Indian population: A cadaveric study

    PubMed Central

    Tewari, Jerina; Mishra, Pravash Ranjan; Tripathy, Sujit Kumar

    2015-01-01

    Background: Many authors have reported the anatomical variation of abductor pollicis longus (APL) around the wrist and its association with de Quervain tenosynovitis (DQT), first carpo-metacarpal arthritis, and trapezio-metacarpal subluxation. From Indian subcontinent, there is only one original article and a few case reports on the variability of APL tendon insertion. Materials and Methods: Fifty formaldehyde preserved cadaveric wrists were dissected to look for the anatomical variation of APL in the Indian population. Results: The APL was found with single tendon in 2, double in 31, triple in 8, and quadruple in 8 extremities. A maximum of 6 tendon-slips were found in one cadaveric wrist. In all hands, the APL had at least one attachment to first metacarpal bone and in 46 hands (92%), there was second insertion to the trapezium bone. Of all tendon-slips of APL (n = 126), 44% of tendons (68 tendons) were inserted into the base of the first metacarpal bone. This was followed by the insertion into the trapezium in 42% tendons (52 tendons). Conclusion: Bi-tendinous APL is commonly observed on the dorsal compartment of the wrist in Indian population and these tendon-slips are commonly attached to the first metacarpal base and trapezium. This variation must be understood by the Indian Orthopedic surgeons as the response to treatment of DQT and reason for first carpo-metacarpal arthritis can be dependent on this anatomical variation. PMID:26538762

  9. The effect of hip joint muscle exercise on muscle strength and balance in the knee joint after meniscal injury.

    PubMed

    Park, Sun Ja; Kim, Young Mi; Kim, Ha Roo

    2016-04-01

    [Purpose] This study aimed to evaluate the effect of hip muscle strengthening on muscle strength and balance in the knee joint after a meniscal injury. [Subjects and Methods] This randomized control study enrolled 24 patients who had undergone arthroscopic treatment after a meniscal injury and began a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into 2 groups of 12 subjects each: gluteus medius resistance exercise group and control group. This study investigated muscle strength and balance in the knee joint flexor, extensor, and abductor during an 8-week period. [Results] Measurements of knee extensor muscle strength revealed no significant difference between the control group and the experimental group. Measurements of abductor muscle strength, however, identified a significant difference between the 2 groups. The groups did not differ significantly with regard to balance measurements. [Conclusion] The results of this study suggest that this subject should be approached in light of the correlation between the hip abductor and injury to the lower extremities. PMID:27190461

  10. The effect of hip joint muscle exercise on muscle strength and balance in the knee joint after meniscal injury

    PubMed Central

    Park, Sun Ja; Kim, Young Mi; Kim, Ha Roo

    2016-01-01

    [Purpose] This study aimed to evaluate the effect of hip muscle strengthening on muscle strength and balance in the knee joint after a meniscal injury. [Subjects and Methods] This randomized control study enrolled 24 patients who had undergone arthroscopic treatment after a meniscal injury and began a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into 2 groups of 12 subjects each: gluteus medius resistance exercise group and control group. This study investigated muscle strength and balance in the knee joint flexor, extensor, and abductor during an 8-week period. [Results] Measurements of knee extensor muscle strength revealed no significant difference between the control group and the experimental group. Measurements of abductor muscle strength, however, identified a significant difference between the 2 groups. The groups did not differ significantly with regard to balance measurements. [Conclusion] The results of this study suggest that this subject should be approached in light of the correlation between the hip abductor and injury to the lower extremities. PMID:27190461

  11. Results of Abductor Pollicis Longus Suspension Ligamentoplasty for Treatment of Advanced First Carpometacarpal Arthritis

    PubMed Central

    Lee, Hyun-Joo; Kim, Poong-Taek; Deslivia, Maria Florencia; Lee, Suk-Joong; Nam, Sang-Jin

    2015-01-01

    Background Suspension ligamentoplasty using abductor pollicis longus (APL) tendon without bone tunneling, was introduced as one of the techniques for treatment of advanced first carpometacarpal (CMC) arthritis. The purpose of this study was to evaluate the radiologic and clinical results of APL suspension ligamentoplasty. Methods The medical records of 19 patients who underwent APL suspension ligamentoplasty for advanced first CMC arthritis between January 2008 and May 2012 were reviewed retrospectively. The study included 13 female and 6 male patients, whose mean age was 62 years (range, 43 to 82 years). For clinical evaluation, we assessed the grip and pinch power, radial and volar abduction angle, thumb adduction (modified Kapandji index), including visual analogue scale (VAS) and Disabilities of the Arm, Shoulder and Hand (DASH) scores. Radiologic evaluation was performed using simple radiographs. Results The mean follow-up was 36 months (range, 19 to 73.7 months). Mean power improved from 18.3 to 27 kg for grip power, from 2.8 to 3.5 kg for tip pinch, and from 4.3 to 5.4 kg for power pinch. All patients showed decreased VAS from 7.2 to 1.7. Radial abduction improved from 71° preoperatively to 82° postoperatively. The modified Kapandji index showed improvement from 6 to 7.3, and mean DASH was improved from 41 to 17.8. The height of the space decreased from 10.8 to 7.1 mm. Only one case had a complication involving temporary sensory loss of the first dorsal web space, which resolved spontaneously. Conclusions The APL suspension ligamentoplasty for treatment of advanced first CMC arthritis yielded satisfactory functional results. PMID:26330961

  12. Patterns of prior offending by child abductors: a comparison of fatal and non-fatal outcomes.

    PubMed

    Beasley, James Oliver; Hayne, Anita S; Beyer, Kristen; Cramer, Gary L; Berson, Sarah Bradley; Muirhead, Yvonne; Warren, Janet I

    2009-01-01

    Our study examines the prior offending of 750 individuals who are known to be responsible for the abduction of a child under the age of 18 years. The first group comprised of 311 offenders (42%) who had abducted a child that was later located alive (found alive, referred to as FA). The second group was comprised of 439 offenders (58%) who had abducted a child that was either found murdered or was still missing and presumed dead (found murdered, referred to as FM). While males perpetrated the majority of the abductions, women perpetrated 31 (10%) of the offenses in the FA group and 10 (2%) of the offenses in the FM group. The average number of prior offenses as reflected in the NCIC criminal history of each offender was seven with these occurring over an average of 12 years. Seventy-five percent of the offenders had prior arrests for an assortment of different crimes while 25% had no known criminal history, a finding that was consistent across both the FA and FM groups. Of those with a criminal history, 41% had been arrested for assault, 40% for larceny, 35% for burglary/breaking and entering, 33% for forcible sex offenses, 25% for drug/narcotic offenses, 21% for weapons law violations, 17% for motor vehicle thefts, 15% for robbery, and 14% for kidnapping. Our findings are congruent with the theme of criminal diversity among child abductors and argue against the specificity in offending that is often assumed with this type of sexual offender. This information is relevant to our understanding of the progression in criminal offending that is manifested by offenders who abduct children and will hopefully be used by law enforcement in helping to direct and focus their investigations.

  13. The architecture and contraction time of intrinsic foot muscles.

    PubMed

    Tosovic, Danijel; Ghebremedhin, Estifanos; Glen, Christopher; Gorelick, Mark; Mark Brown, J

    2012-12-01

    Although critical for effective human locomotion and posture, little data exists regarding the segmentation, architecture and contraction time of the human intrinsic foot muscles. To address this issue, the Abductor Hallucis (AH), Abductor Digiti Minimi (ADM), Flexor Digitorum Brevis (FDB) and Extensor Digitorum Brevis (EDB) were investigated utilizing a cadaveric dissection and a non-invasive whole muscle mechanomyographic (wMMG) technique. The segmental structure and architecture of formaldehyde-fixed foot specimens were determined in nine cadavers aged 60-80 years. The wMMG technique was used to determine the contraction time (Tc) of individual muscle segments, within each intrinsic foot muscle, in 12 volunteers of both genders aged between 19 and 24 years. While the pattern of segmentation and segmental -architecture (e.g. fibre length) and -Tc of individual muscle segments within the same muscle were similar, they varied between muscles. Also, the average whole muscle Tc of FDB was significantly (p < 0.05) shorter (faster) (Tc = 58 ms) than in all other foot muscles investigated (ADM Tc = 72 ms, EDB Tc = 72 ms and ABH Tc = 69 ms). The results suggest that the architecture and contraction time of the FDB reflect its unique direct contribution, through toe flexion, to postural stability and the rapid development of ground reaction forces during forceful activities such as running and jumping.

  14. THE CLINICAL, FUNCTIONAL AND BIOMECHANICAL PRESENTATION OF PATIENTS WITH SYMPTOMATIC HIP ABDUCTOR TENDON TEARS

    PubMed Central

    Retheesh, Theertha; Mutreja, Rinky; Janes, Gregory C.

    2016-01-01

    Background Hip abductor tendon (HAT) tearing is commonly implicated in greater trochanteric pain syndrome (GTPS), though limited information exists on the disability associated with this condition and specific presentation of these patients. Purpose To describe the clinical, functional and biomechanical presentation of patients with symptomatic HAT tears. Secondary purposes were to investigate the association between these clinical and functional measures, and to compare the pain and disability reported by HAT tear patients to those with end-stage hip osteoarthritis (OA). Study Design Prospective case series. Methods One hundred forty-nine consecutive patients with symptomatic HAT tears were evaluated using the Harris (HHS) and Oxford (OHS) Hip Scores, SF-12, an additional series of 10 questions more pertinent to those with lateral hip pain, active hip range of motion (ROM), maximal isometric hip abduction strength, six-minute walk capacity and 30-second single limb stance (SLS) test. The presence of a Trendelenburg sign and pelvis-on-femur (POF) angle were determined via 2D video analysis. An age matched comparative sample of patients with end-stage hip OA was recruited for comparison of all patient-reported outcome scores. Independent t-tests investigated group and limb differences, while analysis of variance evaluated pain changes during the functional tests. Pearson's correlation coefficients investigated the correlation between clinical measures in the HAT tear group. Results No differences existed in patient demographics and patient-reported outcome scores between HAT tear and hip OA cohorts, apart from significantly worse SF-12 mental subscale scores (p = 0.032) in the HAT tear group. Patients with HAT tears demonstrated significantly lower (p < 0.05) hip abduction strength and active ROM in all planes of motion on their affected limb. Pain significantly increased throughout the 30-second SLS test for the HAT tear group, with 57% of HAT tear patients

  15. The effect of tonic contraction of the finger muscle on the motor cortical representation of the contracting adjacent muscle.

    PubMed

    Jono, Yasutomo; Chujo, Yuta; Nomura, Yoshifumi; Tani, Keisuke; Nikaido, Yasutaka; Hatanaka, Ryota; Hiraoka, Koichi

    2015-01-01

    This study examined the effect of tonic contraction of the finger muscle on the motor cortical representation of the contracting adjacent muscle. A representation map of the motor evoked potential (MEP) in the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles was obtained with the subject at rest or during tonic contraction of the ADM muscle while the FDI muscle was tonically contracted. The center of gravity (COG) of the MEP map in the FDI muscle shifted medially during contraction of the ADM muscle. Motor cortical excitability in the motor cortical representation of the FDI muscle that did not overlap with the motor cortical representation of the ADM muscle was suppressed, but motor cortical excitability in the motor cortical representation of the FDI muscle overlapping with the motor cortical representation of the ADM muscle was not suppressed during contraction of the ADM muscle. The motor cortical representation of the FDI muscle not overlapping with the motor cortical representation of the ADM muscle was located lateral to that of the FDI muscle that did overlap with the motor cortical representation of the ADM muscle. Medial shift of the COG of the motor cortical representation of the contracting finger muscle induced by tonic contraction of the adjacent finger muscle must be due to suppression of motor cortical excitability in the lateral part of the representation, which is not shared by the adjacent representation.

  16. Anticipatory and Reactive Response to Falls: Muscle Synergy Activation of Forearm Muscles.

    PubMed

    Couzens, Greg; Kerr, Graham

    2015-10-01

    We investigated the surface electromyogram response of six forearm muscles to falls onto the outstretched hand. The extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, abductor pollicis longus, flexor carpi radialis and flexor carpi ulnaris muscles were sampled from eight volunteers who underwent ten self-initiated falls. All muscles initiated prior to impact. Co-contraction is the most obvious surface electromyogram feature. The predominant response is in the radial deviators. The surface electromyogram timing we recorded would appear to be a complex anticipatory response to falling modified by the effect on the forearm muscles following impact. The mitigation of the force of impact is probably more importantly through shoulder abduction and extension and elbow flexion rather than action of the forearm muscles.

  17. Isokinetic imbalance of hip muscles in soccer players with osteitis pubis.

    PubMed

    Mohammad, Walaa Sayed; Abdelraouf, Osama Ragaa; Elhafez, Salam Mohamed; Abdel-Aziem, Amr Almaz; Nassif, Nagui Sobhi

    2014-01-01

    In this study, we compared the isokinetic torques of hip flexors/extensors and abductors/adductors in soccer players suffering from osteitis pubis (OP), with normal soccer players. Twenty soccer male athletes with OP and 20 normal soccer athletes were included in this study. Peak torque/body weight (PT/BW) was recorded from hip flexor/extensor and abductor/adductor muscles during isokinetic concentric contraction modes at angular velocity of 2.1 rad · s(-1), for both groups. The results showed a significant difference between the normal and OP groups for hip flexors (P < 0.05). The normal group had significant, lower PT/BW value than the OP group for their hip flexors (P < 0.05). The hip flexor/extensor PT ratio of OP affected and non-affected limbs was significantly different from that of normal dominant and non-dominant limbs. There were no significant differences between the normal and OP groups for hip extensor, adductor and abductor muscles (P > 0.05). Regarding the hip adductor/abductor PT ratio, there was no significant difference between the normal and OP groups of athletes (P > 0.05). The OP group displayed increase in hip flexor strength that disturbed the hip flexor/extensor torque ratio of OP. Therefore, increasing the hip extensor strength should be part of rehabilitation programmes of patients with OP. PMID:24499182

  18. Neuromuscular training and muscle strengthening in patients with patellofemoral pain syndrome: a protocol of randomized controlled trial

    PubMed Central

    2014-01-01

    Background Patellofemoral pain syndrome (PFPS) is a common musculoskeletal condition, particularly among women. Patients with PFPS usually experience weakness in the gluteal muscles, as well as pain and impaired motor control during activities of daily living. Strengthening the hip muscles is an effective way of treating this disorder. Neuromuscular training has also been identified as a therapeutic tool, although the benefits of this intervention in patients with PFPS patients remain inconclusive. Design This is a protocol of randomized controlled trial with a blind assessor. Thirty-four women with a clinical diagnosis of PFPS participated. These participants were allocated into two groups (experimental and control). The experimental group performed twelve sessions to strengthen the knee extensors, hip abductor and lateral rotator muscles in association with neuromuscular training of the trunk and lower extremities. The control group performed the same number of sessions to strengthen the muscles of the hip and knee. The primary outcome was functional capacity (Anterior Knee Pain Scale – AKPS) at 4 weeks. Pain intensity, muscle strength and kinematic changes were also measured during the step down test after four weeks of intervention. Follow up assessments were conducted after three and six months to assess functional capacity and pain. The effects of the treatment (i.e. between-group differences) were calculated using mixed linear models. Discussion The present study was initiated on the 1st of April 2013 and is currently in progress. The results of this study may introduce another effective technique of conservative treatment and could guide physical therapists in the clinical decision-making process for women with PFPS. Trial registration Current Controlled Trials NCT01804608. PMID:24884455

  19. Head-Up; An interdisciplinary, participatory and co-design process informing the development of a novel head and neck support for people living with progressive neck muscle weakness.

    PubMed

    Reed, Heath; Langley, Joe; Stanton, Andy; Heron, Nicola; Clarke, Zoe; Judge, Simon; McCarthy, Avril; Squire, Gill; Quinn, Ann; Wells, Oliver; Tindale, Wendy; Baxter, Susan; Shaw, Pamela J; McDermott, Christopher J

    2014-01-01

    This paper presents the Head-Up project, that aims to provide innovative head support to help improve posture, relieve pain and aid communication for people living with progressive neck muscle weakness. The initial focus is motor neurone disease. The case study illustrates collaborative, interdisciplinary research and new product development underpinned by participatory design. The study was initiated by a 2-day stakeholder workshop followed by early proof-of-concept modelling and patient need evidence building. The work subsequently led to a successful NIHR i4i application funding a 24-month iterative design process, patenting, CE marking and clinical evaluation. The evaluation has informed amendments to the proposed design refered to here as the Sheffield Support Snood (SSS). The outcome positively demonstrates use and performance improvements over current neck orthoses and the process of multidisciplinary and user engagement has created a sense of ownership by MND participants, who have since acted as advocates for the product.

  20. Head-Up; An interdisciplinary, participatory and co-design process informing the development of a novel head and neck support for people living with progressive neck muscle weakness.

    PubMed

    Reed, Heath; Langley, Joe; Stanton, Andy; Heron, Nicola; Clarke, Zoe; Judge, Simon; McCarthy, Avril; Squire, Gill; Quinn, Ann; Wells, Oliver; Tindale, Wendy; Baxter, Susan; Shaw, Pamela J; McDermott, Christopher J

    2014-01-01

    This paper presents the Head-Up project, that aims to provide innovative head support to help improve posture, relieve pain and aid communication for people living with progressive neck muscle weakness. The initial focus is motor neurone disease. The case study illustrates collaborative, interdisciplinary research and new product development underpinned by participatory design. The study was initiated by a 2-day stakeholder workshop followed by early proof-of-concept modelling and patient need evidence building. The work subsequently led to a successful NIHR i4i application funding a 24-month iterative design process, patenting, CE marking and clinical evaluation. The evaluation has informed amendments to the proposed design refered to here as the Sheffield Support Snood (SSS). The outcome positively demonstrates use and performance improvements over current neck orthoses and the process of multidisciplinary and user engagement has created a sense of ownership by MND participants, who have since acted as advocates for the product. PMID:26453038

  1. [Obese woman presenting as vocal cord abductor paralysis and floppy arytenoid associated with early signs of multiple system atrophy].

    PubMed

    Sakuta, Hideki; Miyamoto, Masayuki; Suzuki, Keisuke; Miyamoto, Tomoyuki; Nakajima, Itsuo; Nakamura, Toshiki; Hirata, Koichi

    2012-01-01

    In multiple system atrophy (MSA), sleep-related breathing disorders are commonly observed, including vocal cord abductor paralysis (VCAP), which can cause sudden death. In its early stage, VCAP occurs only during sleep, but as the disease progresses, it appears when both awake and asleep. We encountered a 59-year-old obese woman who had been under continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea syndrome (OSAS) for approximately one year but later developed acute respiratory failure because of VCAP. VCAP was the predominant finding that led to the diagnosis of MSA in our patient. On laryngoscopic examination, the movement of the patient's larynx was normal during wakefulness, but VCAP, paradoxical movements of the vocal cord and a floppy arytenoid were observed during drug-induced sleep. We suggest that detection of VCAP and laryngopharyngeal abnormalities such as floppy arytenoid in the early stage of MSA is important for determining treatment options.

  2. [Obese woman presenting as vocal cord abductor paralysis and floppy arytenoid associated with early signs of multiple system atrophy].

    PubMed

    Sakuta, Hideki; Miyamoto, Masayuki; Suzuki, Keisuke; Miyamoto, Tomoyuki; Nakajima, Itsuo; Nakamura, Toshiki; Hirata, Koichi

    2012-01-01

    In multiple system atrophy (MSA), sleep-related breathing disorders are commonly observed, including vocal cord abductor paralysis (VCAP), which can cause sudden death. In its early stage, VCAP occurs only during sleep, but as the disease progresses, it appears when both awake and asleep. We encountered a 59-year-old obese woman who had been under continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea syndrome (OSAS) for approximately one year but later developed acute respiratory failure because of VCAP. VCAP was the predominant finding that led to the diagnosis of MSA in our patient. On laryngoscopic examination, the movement of the patient's larynx was normal during wakefulness, but VCAP, paradoxical movements of the vocal cord and a floppy arytenoid were observed during drug-induced sleep. We suggest that detection of VCAP and laryngopharyngeal abnormalities such as floppy arytenoid in the early stage of MSA is important for determining treatment options. PMID:22790804

  3. Weakness of the Pelvic Floor Muscle and Bladder Neck Is Predicted by a Slight Rise in Abdominal Pressure During Bladder Filling: A Video Urodynamic Study in Children

    PubMed Central

    2016-01-01

    Purpose: To investigate the significance of slowly rising abdominal pressure (SRAP), which is often observed in nonneurogenic children during bladder filling in video urodynamic studies (VUDSs). Methods: The records of patients who underwent VUDS from July 2011 to June 2013 were reviewed. SRAP was defined as a rising curve over 5 cm H2O from the baseline abdominal pressure during the filling phase in VUDS. Bladder descent was defined when the base of the bladder was below the upper line of the pubic symphysis. An open bladder neck was defined as the opening of the bladder neck during the filling phase. Results: Of the 488 patients, 285 were male patients. The mean age at VUDS was 3.7 years (range, 0.2–17.6 years). The VUDS findings were as follows: SRAP, 20.7% (101 of 488); descending bladder, 14.8% (72 of 488); and bladder neck opening, 4.3% (21 of 488). Of the 72 patients with a descending bladder, 84.7% had SRAP. A significant difference in the presence of SRAP was found between the descending bladder and the normal bladder (P<0.001). Of the 101 patients with SRAP, 40 (39.6%) did not have a descending bladder. Of the 40 patients, 14 (35.0%) had a bladder neck opening, which was a high incidence compared with the 4.3% in all subjects (P<0.001). Conclusions: SRAP was associated with a descending bladder or a bladder neck opening, suggesting that SRAP is a compensatory response to urinary incontinence. SRAP may also predict decreased function of the bladder neck or pelvic floor muscle. PMID:27032558

  4. Examination of Hand Muscle Activation and Motor Unit Indices Derived from Surface EMG in Chronic Stroke

    PubMed Central

    Li, Xiaoyan; Liu, Jie; Li, Sheng; Wang, Ying-Chih

    2014-01-01

    In this study, we used muscle and motor unit indices, derived from convenient surface electromyography (EMG) measurements, for examination of paretic muscle changes post stroke. For 12 stroke subjects, compound muscle action potential and voluntary surface EMG signals were recorded from paretic and contralateral first dorsal interosseous, abductor pollicis brevis, and abductor digiti minimi muscles. Muscle activation index (AI), motor unit number index (MUNIX), and motor unit size index (MUSIX) were then calculated for each muscle. There was a significant AI reduction for all the three muscles in paretic side compared with contralateral side, providing an evidence of muscle activation deficiency after stroke. The hand MUNIX (defined by summing the values from the three muscles) was significantly reduced in paretic side compared with contralateral side, whereas the hand MUSIX was not significantly different. Furthermore, diverse changes in MUNIX and MUSIX were observed from the three muscles. A major feature of the present examinations is the primary reliance on surface EMG, which offers practical benefits because it is noninvasive, induces minimal discomfort and can be performed quickly. PMID:24967982

  5. Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.

    1957-06-01

    Experimental results on the non-conservation of parity and charge conservation in weak interactions are reviewed. The two-component theory of the neutrino is discussed. Lepton reactions are examined under the assumption of the law of conservation of leptons and that the neutrino is described by a two- component theory. From the results of this examination, the universal Fermi interactions are analyzed. Although reactions involving the neutrino can be described, the same is not true of reactions which do not involve the lepton, as the discussion of the decay of K mesons and hyperons shows. The question of the invariance of time reversal is next examined. (J.S.R.)

  6. Restoration of pinch in intrinsic muscles of the hand.

    PubMed

    Lee, Steve K; Wisser, Jamie R

    2012-02-01

    The primary intrinsic muscles responsible for key and tip pinch are the adductor pollicis, first dorsal interosseous and flexor pollicis brevis muscles. Numerous conditions can lead to their dysfunction. Non-operative treatment consists of exercises of the compensating extensor pollicis longus and flexor pollicis longus muscles and use of adaptive devices, such as larger grips. Operative treatments include tendon transfers and joint fusions. The most common tendon transfer procedures include transfering of the extensor carpi radialis brevis to the adductor pollicis muscle or transfering of the abductor pollicis longus to the first dorsal interosseous muscle. Both require use of extension tendon grafts. In cases of joint instability or arthrosis, arthrodesis of the thumb and index finger MP or IP joints, alone or in combination, may be indicated. PMID:22117923

  7. Muscle fiber types composition and type identified endplate morphology of forepaw intrinsic muscles in the rat.

    PubMed

    Pan, Feng; Mi, Jing-Yi; Zhang, Yan; Pan, Xiao-Yun; Rui, Yong-Jun

    2016-06-01

    The failure to accept reinnervation is considered to be one of the reasons for the poor motor functional recovery of intrinsic hand muscles (IHMs) after nerve injury. Rat could be a suitable model to be used in simulating motor function recovery of the IHMs after nerve injury as to the similarities in function and anatomy of the muscles between human and rat. However, few studies have reported the muscle fiber types composition and endplate morphologic characteristics of intrinsic forepaw muscles (IFMs) in the rat. In this study, the myosin heavy chain isoforms and acetylcholine receptors were stained by immunofluorescence to show the muscle fiber types composition and endplates on type-identified fibers of the lumbrical muscles (LMs), interosseus muscles (IMs), abductor digiti minimi (AM) and flexor pollicis brevis (FM) in rat forepaw. The majority of IFMs fibers were labeled positively for fast-switch fiber. However, the IMs were composed of only slow-switch fiber. With the exception of the IMs, the other IFMs had a part of hybrid fibers. Two-dimensional morphological characteristics of endplates on I and IIa muscle fiber had no significant differences among the IFMs. The LMs is the most suitable IFMs of rat to stimulate reinnervation of the IHMs after nerve injury. Gaining greater insight into the muscle fiber types composition and endplate morphology in the IFMs of rat may help understand the pathological and functional changes of IFMs in rat model stimulating reinnervation of IHMs after peripheral nerve injury.

  8. Your Muscles

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Your Muscles KidsHealth > For Kids > Your Muscles Print A A ... and skeletal (say: SKEL-uh-tul) muscle. Smooth Muscles Smooth muscles — sometimes also called involuntary muscles — are ...

  9. Lower Extremity Muscle Strength After Anterior Cruciate Ligament Injury and Reconstruction

    PubMed Central

    Thomas, Abbey C.; Villwock, Mark; Wojtys, Edward M.; Palmieri-Smith, Riann M.

    2013-01-01

    Context: Quadriceps and hamstrings weakness occurs frequently after anterior cruciate ligament (ACL) injury and reconstruction. Evidence suggests that knee injury may precipitate hip and ankle muscle weakness, but few data support this contention after ACL injury and reconstruction. Objective: To determine if hip, knee, and ankle muscle weakness present after ACL injury and after rehabilitation for ACL reconstruction. Design: Case-control study. Setting: University research laboratory. Patients or Other Participants: Fifteen individuals with ACL injury (8 males, 7 females; age = 20.27 ± 5.38 years, height = 1.75 ± 0.10 m, mass = 74.39 ± 13.26 kg) and 15 control individuals (7 men, 8 women; age = 24.73 ± 3.37 years, height = 1.75 ± 0.09 m, mass = 73.25 ± 13.48 kg). Intervention(s): Bilateral concentric strength was assessed at 60°/s on an isokinetic dynamometer. The participants with ACL injury were tested preoperatively and 6 months postoperatively. Control participants were tested on 1 occasion. Main Outcome Measures: Hip-flexor, -extensor, -abductor, and -adductor; knee-extensor and -flexor; and ankle–plantar-flexor and -dorsiflexor strength (Nm/kg). Results: The ACL-injured participants demonstrated greater hip-extensor (percentage difference = 19.7, F1,14 = 7.28, P = .02) and -adductor (percentage difference = 16.3, F1,14 = 6.15, P = .03) weakness preoperatively than postoperatively, regardless of limb, and greater postoperative hip-adductor strength (percentage difference = 29.0, F1,28 = 10.66, P = .003) than control participants. Knee-extensor and -flexor strength were lower in the injured than in the uninjured limb preoperatively and postoperatively (extensor percentage difference = 34.6 preoperatively and 32.6 postoperatively, t14 range = −4.59 to −4.23, P ≤ .001; flexor percentage difference = 30.6 preoperatively and 10.6 postoperatively, t14 range = −6.05 to −3.24, P < .05) with greater knee-flexor (percentage difference = 25.3, t14 =

  10. The effects of hip external rotator exercises and toe-spread exercises on lower extremity muscle activities during stair-walking in subjects with pronated foot

    PubMed Central

    Goo, Young-Mi; Kim, Da-Yeon; Kim, Tae-Ho

    2016-01-01

    [Purpose] The purpose of the present study was to examine the effects of toe-spread (TS) exercises and hip external rotator strengthening exercises for pronated feet on lower extremity muscle activities during stair-walking. [Subjects and Methods] The participants were 20 healthy adults with no present or previous pain, no past history of surgery on the foot or the ankle, and no foot deformities. Ten subjects performed hip external rotator strengthening exercises and TS exercises and the remaining ten subjects performed only TS exercises five times per week for four weeks. [Results] Less change in navicular drop height occurred in the group that performed hip external rotator exercises than in the group that performed only TS exercises. The group that performed only TS exercises showed increased abductor hallucis muscle activity during both stair-climbing and -descending, and the group that performed hip external rotator exercises showed increased muscle activities of the vastus medialis and abductor hallucis during stair-climbing and increased muscle activity of only the abductor hallucis during stair-descending after exercise. [Conclusion] Stair-walking can be more effectively performed if the hip external rotator muscle is strengthened when TS exercises are performed for the pronated foot. PMID:27134364

  11. Role of muscles in the stabilization of ligament-deficient wrists.

    PubMed

    Esplugas, Mireia; Garcia-Elias, Marc; Lluch, Alex; Llusá Pérez, Manuel

    2016-01-01

    This article reviews the results of a series of cadaver investigations aimed at clarifying the role of muscles in the stabilization of ligament-deficient wrists. According to these studies, isometric contraction of some forearm muscles induces midcarpal (MC) supination (ie, the abductor pollicis longus, extensor carpi radialis longus, and flexor carpi ulnaris), whereas other muscles induce MC pronation (ie, the extensor carpi ulnaris). Because MC supination implies tightening of the volar scaphoid-distal row ligaments, the MC supination muscles are likely to prevent scaphoid collapse of wrists with scapholunate ligament insufficiency. MC pronator muscles, by contrast, would be beneficial in stabilizing wrists with ulnar-sided ligament deficiencies owing to their ability to tighten the triquetrum-distal row ligaments. Should these laboratory findings be validated by additional clinical research, proprioceptive reeducation of selected muscles could become an important tool for the treatment of dynamic carpal instabilities. PMID:27264901

  12. The functional morphology of the accessory interosseous muscle in the gibbon hand: determination of locomotor and manipulatory compromises.

    PubMed Central

    Susman, R L; Jungers, W L; Stern, J T

    1982-01-01

    The evidence for two functional roles of M. accessorius interosseus can be adduced as follows: (1) abduction of the whole finger is clearly required to resist the force of the thumb against the index during pinch grasp (Fig. 4) and when greater resistance is applied to the food, activity increases in the muscle. (2) The muscle also flexes the metacarpophalangeal joint at the onset of grasp on the ladder rung. In hanging from the finger tips or from the cage top, with the metacarpophalangeal joints extended, the muscle goes silent. From the functional point of view, the name given by Huxley (1871) to the M. accessorius interosseus ('abductor tertii internodii secundi digiti') is perhaps the most appropriate one. For reasons of economy, however, we favour continued use of the nomen Musculus accessorius interosseus (Fitzwilliams, 1910) or accessory interosseous muscle. The name coined by Keith (1894; p. 299) which implies that this muscle is an extensor of the distal interphalangeal joint, and any suggestions that the muscle functions primarily to flex the proximal interphalangeal joint are less appropriate or in error. The EMG data reveal that the M. accessorius interosseus is primarily an abductor of the index finger in gibbons, and we suggest that it is a unique feature of lesser apes that has evolved in compensation for a deep thumb-index cleft and the loss of the radial moiety of the first dorsal interosseous muscle. The primary role of this specialized muscle is in thumb-index pinch grasping. Images Fig. 5 PMID:7076537

  13. The Gluteus Medius Vs. Thigh Muscles Strength Ratio and Their Relation to Electromyography Amplitude During a Farmer’s Walk Exercise

    PubMed Central

    Stastny, Petr; Lehnert, Michal; Zaatar, Amr; Svoboda, Zdenek; Xaverova, Zuzana; Pietraszewski, Przemysław

    2015-01-01

    The strength ratio between hamstrings and quadriceps (H/Q) is associated with knee injuries as well as hip abductor muscle (HAB) weakness. Sixteen resistance trained men (age, 32.5 ± 4.2 years) performed 5 s maximal isometric contractions at 75° of knee flexion/extension and 15° of hip abduction on a dynamometer. After this isometric test they performed a Farmer’s walk exercise to find out if the muscle strength ratio predicted the electromyography amplitude expressed as a percentage of maximum voluntary isometric contraction (%MVIC). The carried load represented a moderate intensity of 75% of the exercise six repetitions maximum (6RM). Electromyography data from the vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF) and gluteus medius (Gmed) on each leg were collected during the procedure. The groups selected were participants with H/Q ≥ 0.5, HQ < 0.5, HAB/H ≥ 1, HAB/H < 1, HAB/Q ≥ 0.5 and HAB/Q < 0.5. One way ANOVA showed that Gmed activity was significantly greater in the group with HAB/H < 1 (42 ± 14 %MVIC) as compared to HAB/H ≥ 1 (26 ± 10 %MVIC) and HAB/Q < 0.5 (47 ± 19 %MVIC) compared to HAB/Q ≥ 0.5 (26 ± 12 %MVIC). The individuals with HAB/H < 1 were found to have greater activation of their Gmed during the Farmer’s walk exercise. Individuals with HAB/Q < 0.5 had greater activation of the Gmed. Gmed strength ratios predict the muscle involvement when a moderate amount of the external load is used. The Farmer’s walk is recommended as an exercise which can strengthen the gluteus medius, especially for individuals with a HAB/H ratio < 1 and HAB/Q < 0.5. PMID:25964819

  14. Aging changes in the bones - muscles - joints

    MedlinePlus

    Osteoporosis and aging; Muscle weakness associated with aging; Osteoarthritis ... short bursts of high-speed performance. COMMON PROBLEMS Osteoporosis is a common problem, especially for older women. ...

  15. Characteristics of corticospinal projections to the intrinsic hand muscles in skilled harpists.

    PubMed

    Buick, Alison R; Kennedy, Niamh C; Carson, Richard G

    2016-01-26

    The process of learning to play a musical instrument necessarily alters the functional organisation of the cortical motor areas that are involved in generating the required movements. In the case of the harp, the demands placed on the motor system are quite specific. During performance, all digits with the sole exception of the little finger are used to pluck the strings. With a view to elucidating the impact of having acquired this highly specialised musical skill on the characteristics of corticospinal projections to the intrinsic hand muscles, focal transcranial magnetic stimulation (TMS) was used to elicit motor evoked potentials (MEPs) in three muscles (of the left hand): abductor pollicis brevis (APB); first dorsal interosseous (FDI); and abductor digiti minimi (ADM) in seven harpists. Seven non-musicians served as controls. With respect to the FDI muscle-which moves the index finger, the harpists exhibited reliably larger MEP amplitudes than those in the control group. In contrast, MEPs evoked in the ADM muscle-which activates the little finger, were smaller in the harpists than in the non-musicians. The locations on the scalp over which magnetic stimulation elicited discriminable responses in ADM also differed between the harpists and the non-musicians. This specific pattern of variation in the excitability of corticospinal projections to these intrinsic hand muscles exhibited by harpists is in accordance with the idiosyncratic functional demands that are imposed in playing this instrument. PMID:26673887

  16. Comments and corrections on 3D modeling studies of locomotor muscle moment arms in archosaurs

    PubMed Central

    Maidment, Susannah C.R.; Schachner, Emma R.; Barrett, Paul M.

    2015-01-01

    In a number of recent studies we used computer modeling to investigate the evolution of muscle leverage (moment arms) and function in extant and extinct archosaur lineages (crocodilians, dinosaurs including birds and pterosaurs). These studies sought to quantify the level of disparity and convergence in muscle moment arms during the evolution of bipedal and quadrupedal posture in various independent archosaur lineages, and in doing so further our understanding of changes in anatomy, locomotion and ecology during the group’s >250 million year evolutionary history. Subsequent work by others has led us to re-evaluate our models, which revealed a methodological error that impacted on the results obtained from the abduction–adduction and long-axis rotation moment arms in our published studies. In this paper we present corrected abduction–adduction and long axis rotation moment arms for all our models, and evaluate the impact of this new data on the conclusions of our previous studies. We find that, in general, our newly corrected data differed only slightly from that previously published, with very few qualitative changes in muscle moments (e.g., muscles originally identified as abductors remained abductors). As a result the majority of our previous conclusions regarding the functional evolution of key muscles in these archosaur groups are upheld. PMID:26500810

  17. Autoimmune muscle disease.

    PubMed

    Mammen, Andrew

    2016-01-01

    Patients with polymyositis (PM), dermatomyositis (DM), and immune-mediated necrotizing myopathy (IMNM) present with the subacute onset of symmetric proximal muscle weakness, elevated muscle enzymes, myopathic findings on electromyography, and autoantibodies. DM patients are distinguished by their cutaneous manifestations. Characteristic features on muscle biopsy include the invasion of nonnecrotic muscle fibers by T cells in PM, perifascicular atrophy in DM, and myofiber necrosis without prominent inflammation in IMNM. Importantly, these are regarded as autoimmune diseases and most patients respond partially, if not completely, to immunosuppressive therapy. Patients with inclusion body myositis (IBM) usually present with the insidious onset of asymmetric weakness in distal muscles (e.g., wrist flexors, and distal finger flexors), often when more proximal muscle groups are relatively preserved. Although IBM muscle biopsies usually have focal invasion of myofibers by lymphocytes, the majority of IBM biopsies also include rimmed vacuoles. While most IBM patients do have autoantibodies, treatment with immunosuppressive agents does not improve their clinical course. Along with the presence of abnormally aggregated proteins on muscle biopsy, the refractory nature and relentless course of IBM suggest that the underlying pathophysiology may include a dominant myodegenerative component. This chapter will focus on the epidemiology, clinical presentation, and treatment of the autoimmune myopathies and IBM. An emphasis will be placed on recent advances, indicating that these are a diverse family of diseases and that each of more than a dozen myositis autoantibodies is associated with a distinct clinical phenotype. PMID:27112692

  18. Characteristics of the electrophysiological activity of muscles attached to the transverse carpal ligament in carpal tunnel syndrome.

    PubMed

    Horiguchi, Gen; Aoki, Takafumi; Ito, Hiromoto

    2011-01-01

    The main cause of carpal tunnel syndrome (CTS) remains unknown. Stiffness of the subcutaneous area of the volar aspect of the carpal tunnel is present in many patients and suggests that the stiffness of muscles attached to the transverse carpal ligament is increased. We performed an electrophysiological study to investigate muscle activities and to clarify whether the stiffness of muscles attached to the transverse carpal ligament is involved in the pathogenesis of CTS. The subjects of this study included 16 patients with early CTS showing no motor dysfunction. Both thenar muscles (opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis) and hypothenar muscles (opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis) were investigated. Surface electrodes were placed on each muscle, and maximum voluntary contractions with the thumb and little finger in opposition were maintained for 3 seconds in all patients and in 7 control subjects. Electromyographs were subjected to fast Fourier transform analysis, and the root mean square (RMS) and the mean power frequency (MPF) were determined for each muscle. The RMS of the opponens pollicis was significantly less in hands affected by CTS (292.8 µV) than in healthy hands (405.9 µV). The RMS did not differ between affected hands and healthy hands for the other 2 thenar muscles but did differ significantly for the hypothenar muscles. The MPF did not differ between affected hands and healthy hands for any muscle. The results show that electrophysiological differences are present among muscles innervated by the median nerve and that hypothenar muscles originally unrelated to median nerve dysfunction are also affected in early CTS. These results suggest that modulation of muscles attached to the transverse carpal ligament is involved in the pathogenesis of CTS.

  19. Muscle Cramps

    MedlinePlus

    Muscle cramps are sudden, involuntary contractions or spasms in one or more of your muscles. They often occur after exercise or at night, ... to several minutes. It is a very common muscle problem. Muscle cramps can be caused by nerves ...

  20. Muscle atrophy

    MedlinePlus

    Muscle wasting; Wasting; Atrophy of the muscles ... There are two types of muscle atrophy: disuse and neurogenic. Disuse atrophy is caused by not using the muscles enough . This type of atrophy can often be ...

  1. Muscle biopsy

    MedlinePlus

    ... the removal of a small piece of muscle tissue for examination. ... dystrophy Myopathic changes (destruction of the muscle) Necrosis (tissue death) of muscle Necrotizing vasculitis Traumatic muscle damage Polymyositis Additional conditions ...

  2. Relationships between lower limb muscle strength and locomotor capacity in children and adolescents with cerebral palsy who walk independently.

    PubMed

    Ferland, Chantale; Lepage, Céline; Moffet, Hélène; Maltais, Désirée B

    2012-08-01

    This study aimed to quantify relationships between lower limb muscle strength and locomotor capacity for children and adolescents with cerebral palsy (CP) to identify key muscle groups for strength training. Fifty 6- to 16-year-olds with CP (Gross Motor Function Classification System level I or II) participated. Isometric muscle strength of hip flexor and abductor, knee flexor and extensor, and ankle dorsiflexor muscles was measured using hand-held dynamometry. Ankle plantar flexor concentric muscle strength was assessed as the maximal number of unilateral heel rises. Locomotor capacity was evaluated by the 6-min walk test (6MWT), 10-meter Shuttle Run Test (10mSRT), and Timed Up and Down Stairs Test (TUDS). With control for age, sex, and height, hip flexor and ankle plantar flexor strength explained 47.8% of the variance in the 6MWT and 32.9% of variance in the TUDS and hip abductor isometric strength explained 43.5% of the variance in the 10mSRT. Avenues for future research include randomized controlled trials that specifically target hip flexor muscles, as this has not previously been done, and determining factors other than strength that are likely related to locomotor capacity of children and adolescents with CP.

  3. Muscle regeneration after sepsis.

    PubMed

    Bouglé, Adrien; Rocheteau, Pierre; Sharshar, Tarek; Chrétien, Fabrice

    2016-01-01

    Severe critical illness is often complicated by intensive care unit-acquired weakness (ICU-AW), which is associated with increased ICU and post-ICU mortality, delayed weaning from mechanical ventilation and long-term functional disability. Several mechanisms have been implicated in the pathophysiology of ICU-AW, but muscle regeneration has not been investigated to any extent in this context, even though its involvement is suggested by the protracted functional consequences of ICU-AW. Recent data suggest that muscle regeneration could be impaired after sepsis, and that mesenchymal stem cell treatment could improve the post-injury muscle recovery. PMID:27193340

  4. [A strong man with a weak shoulder].

    PubMed

    Henket, Marjolijn; Lycklama á Nijeholt, Geert J; van der Zwaal, Peer

    2013-01-01

    A 47-year-old former olympic athlete had pain and weakness of his left shoulder. There was no prior trauma. He had full range-of-motion and a scapular dyskinesia. There was atrophy of the trapezius and sternocleidomastoideus muscles. He was diagnosed with 'idiopathic neuritis of the accessorius nerve'. PMID:24326139

  5. Macroscopic study of the functional significance of the forearm muscles in the giant panda.

    PubMed

    Endo, Hideki; Sasaki, Motoki; Narushima, Etsuo; Komiya, Teruyuki; Hayashida, Akiko; Hayashi, Yoshihiro; Stafford, Brian J

    2003-08-01

    The extensor and flexor group muscles and their related muscles were functional-morphologically observed in the dead body of the giant panda to clarify the action of the forearm and the palm in the manipulation of the species. The Musculus flexor carpi ulnaris had two developed heads, however, we can conclude that the contraction of this muscle slightly changes the angle of the accessory carpal bone to the ulna. The data pointed out that the accessory carpal bone acts as a supporting post, when the giant panda seizes the object. The M. abductor digiti I longus possessed the well-developed origin in both ulna and radius. These findings suggest that this muscle may function as a supinator of the forearm. We also suggest that the well-developed M. pronator quadratus and M. pronator teres, and the proximal part of the M. abductor digiti I longus and the M. supinator may efficiently contribute to the pronator-spinator action of the forearm, when the giant panda brings the food to its mouth using the manipulation system equipped in the palm region.

  6. Relationships of ultrasound measures of intrinsic foot muscle cross-sectional area and muscle volume with maximum toe flexor muscle strength and physical performance in young adults

    PubMed Central

    Abe, Takashi; Tayashiki, Kota; Nakatani, Miyuki; Watanabe, Hironori

    2016-01-01

    [Purpose] To investigate the relationships between toe flexor muscle strength with (TFS-5-toes) and without (TFS-4-toes) the contribution of the great toe, anatomical and physiological muscle cross-sectional areas (CSA) of intrinsic toe flexor muscle and physical performance were measured. [Subjects] Seventeen men (82% sports-active) and 17 women (47% sports-active), aged 20 to 35 years, volunteered. [Methods] Anatomical CSA was measured in two intrinsic toe flexor muscles (flexor digitorum brevis [FDB] and abductor hallucis) by ultrasound. Muscle volume and muscle length of the FDB were also estimated, and physiological CSA was calculated. [Results] Both TFS-5-toes and TFS-4-toes correlated positively with walking speed in men (r=0.584 and r=0.553, respectively) and women (r=0.748 and r=0.533, respectively). Physiological CSA of the FDB was significantly correlated with TFS-5-toes (r=0.748) and TFS-4-toes (r=0.573) in women. In men, physiological CSA of the FDB correlated positively with TFS-4-toes (r=0.536), but not with TFS-5-toes (r=0.333). [Conclusion] Our results indicate that physiological CSA of the FDB is moderately associated with TFS-4-toes while toe flexor strength correlates with walking performance. PMID:26957721

  7. Weak scale supersymmetry

    SciTech Connect

    Hall, L.J. California Univ., Berkeley, CA . Dept. of Physics)

    1990-11-12

    An introduction to the ideas and current state of weak scale supersymmetry is given. It is shown that LEP data on Z decays has already excluded two of the most elegant models of weak scale supersymmetry. 14 refs.

  8. Skeletal muscle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are approximately 650-850 muscles in the human body these include skeletal (striated), smooth and cardiac muscle. The approximation is based on what some anatomists consider separate muscle or muscle systems. Muscles are classified based on their anatomy (striated vs. smooth) and if they are v...

  9. The influence of changes in trunk and pelvic posture during single leg standing on hip and thigh muscle activation in a pain free population

    PubMed Central

    2014-01-01

    Background Thigh muscle injuries commonly occur during single leg loading tasks and patterns of muscle activation are thought to contribute to these injuries. The influence trunk and pelvis posture has on hip and thigh muscle activation during single leg stance is unknown and was investigated in a pain free population to determine if changes in body posture result in consistent patterns of changes in muscle activation. Methods Hip and thigh muscle activation patterns were compared in 22 asymptomatic, male subjects (20–45 years old) in paired functionally relevant single leg standing test postures: Anterior vs. Posterior Trunk Sway; Anterior vs. Posterior Pelvic Rotation; Left vs. Right Trunk Shift; and Pelvic Drop vs. Raise. Surface EMG was collected from eight hip and thigh muscles calculating Root Mean Square. EMG was normalized to an “upright standing” reference posture. Repeated measures ANOVA was performed along with associated F tests to determine if there were significant differences in muscle activation between paired test postures. Results In right leg stance, Anterior Trunk Sway (compared to Posterior Sway) increased activity in posterior sagittal plane muscles, with a concurrent deactivation of anterior sagittal plane muscles (p: 0.016 - <0.001). Lateral hip abductor muscles increased activation during Left Trunk Shift (compared to Right) (p :≤ 0.001). Lateral Pelvic Drop (compared to Raise) decreased activity in hip abductors and increased hamstring, adductor longus and vastus lateralis activity (p: 0.037 - <0.001). Conclusion Changes in both trunk and pelvic posture during single leg stance generally resulted in large, predictable changes in hip and thigh muscle activation in asymptomatic young males. Changes in trunk position in the sagittal plane and pelvis position in the frontal plane had the greatest effect on muscle activation. Investigation of these activation patterns in clinical populations such as hip and thigh muscle injuries may

  10. Muscle Deoxygenation Causes Muscle Fatigue

    NASA Technical Reports Server (NTRS)

    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.

  11. Muscle diseases: the muscular dystrophies.

    PubMed

    McNally, Elizabeth M; Pytel, Peter

    2007-01-01

    Dystrophic muscle disease can occur at any age. Early- or childhood-onset muscular dystrophies may be associated with profound loss of muscle function, affecting ambulation, posture, and cardiac and respiratory function. Late-onset muscular dystrophies or myopathies may be mild and associated with slight weakness and an inability to increase muscle mass. The phenotype of muscular dystrophy is an endpoint that arises from a diverse set of genetic pathways. Genes associated with muscular dystrophies encode proteins of the plasma membrane and extracellular matrix, and the sarcomere and Z band, as well as nuclear membrane components. Because muscle has such distinctive structural and regenerative properties, many of the genes implicated in these disorders target pathways unique to muscle or more highly expressed in muscle. This chapter reviews the basic structural properties of muscle and genetic mechanisms that lead to myopathy and muscular dystrophies that affect all age groups.

  12. Muscle disorder

    MedlinePlus

    Myopathic changes; Myopathy; Muscle problem ... Blood tests sometimes show abnormally high muscle enzymes. If a muscle disorder might also affect other family members, genetic testing may be done. When someone has symptoms and signs ...

  13. Muscle strain of the subscapularis muscle: a case report.

    PubMed

    Iwamoto, Jun; Takeda, Tsuyoshi; Ogawa, Kiyohisa; Matsumoto, Hideo

    2007-09-01

    We report on a case of muscle strain of the subscapularis muscle in a baseball player. An out-fielder (throws right-handed and bats left-handed) hurt his right shoulder while playing baseball. He complained of right-shoulder pain just after he forcefully hit his right hand against the fence in an attempt to jump and catch a flying ball with a glove on the left hand during a baseball game. Fat-suppressed T2-weighted magnetic resonance images (MRIs) of the right shoulder joint revealed muscle strain in the middle part of the subscapularis muscle, and the injury was surmised to have occurred on account of eccentric contraction of the subscapularis muscle. The case was considered to have moderate muscle strain, because he had modest muscle weakness with a negative lift-off test. Active stretching exercises were begun just after his first visit to our clinic, and throwing exercises were started 3 weeks later, by when the right-shoulder pain had completely disappeared. Repeat MRIs of the right shoulder joint obtained 4 weeks after his first visit to our clinic revealed a significant reduction of the high-intensity lesions in the subscapularis muscle. Conservative treatment was effective for managing moderate muscle strain of the subscapularis muscle. Muscle strain of the subscapularis muscle should be taken into consideration in the differential diagnosis of shoulder injuries in athletes.

  14. Preferential denervation of the adductor muscles of the equine larynx. II: Nerve pathology.

    PubMed

    Duncan, I D; Reifenrath, P; Jackson, K F; Clayton, M

    1991-03-01

    The terminal branches of the recurrent laryngeal nerve (RLN) of three normal ponies and six horses with sub-clinical laryngeal disease were examined qualitatively and quantitatively in an attempt to explain the preferential denervation of the laryngeal adductor muscles in the neuropathy of idiopathic laryngeal hemiplegia (ILH). The myelinated fibre spectra of all the motor nerve fibres in the left and right abductor and adductor branches of the RLN in three normal ponies were measured. The density of myelinated fibres was also calculated. There was no significant difference between the larger group of myelinated fibres in the adductor or abductor branches. In the six horses with laryngeal hemiparesis, however, there was a marked preferential loss of the medium/large size myelinated fibres in the left adductor branch, although nerve fibre densities were not significantly different. While no simple morphometrical feature was found to explain the selective muscle denervation, the greater loss of large diameter myelinated fibres in the adductor branches confirms the earlier observation of adductor muscle susceptibility in the neuropathy of ILH.

  15. Cerebellar brain inhibition in the target and surround muscles during voluntary tonic activation.

    PubMed

    Panyakaew, Pattamon; Cho, Hyun Joo; Srivanitchapoom, Prachaya; Popa, Traian; Wu, Tianxia; Hallett, Mark

    2016-04-01

    Motor surround inhibition is the neural mechanism that selectively favours the contraction of target muscles and inhibits nearby muscles to prevent unwanted movements. This inhibition was previously reported at the onset of a movement, but not during a tonic contraction. Cerebellar brain inhibition (CBI) is reduced in active muscles during tonic activation; however, it has not been studied in the surround muscles. CBI was evaluated in the first dorsal interosseus (FDI) muscle as the target muscle, and the abductor digiti minimi, flexor carpi radialis and extensor carpi radialis muscles as surround muscles, during rest and tonic activation of the FDI muscle in 21 subjects. Cerebellar stimulation was performed under magnetic resonance imaging-guided neuronavigation targeting lobule VIII of the cerebellar hemisphere. Stimulus intensities for cerebellar stimulation were based on the resting motor cortex threshold (RMT) and adjusted for the depth difference between the cerebellar and motor cortices. We used 90-120% of the adjusted RMT as the conditioning stimulus intensity during rest. The intensity that generated the best CBI at rest in the FDI muscle was selected for use during tonic activation. During selective tonic activation of the FDI muscle, CBI was significantly reduced only for the FDI muscle, and not for the surround muscles. Unconditioned motor evoked potential sizes were increased in all muscles during FDI muscle tonic activation as compared with rest, despite background electromyography activity increasing only for the FDI muscle. Our study suggests that the cerebellum may play an important role in selective tonic finger movement by reducing its inhibition in the motor cortex only for the relevant agonist muscle.

  16. Postselected weak measurement beyond the weak value

    SciTech Connect

    Geszti, Tamas

    2010-04-15

    Closed expressions are derived for the quantum measurement statistics of pre- and postselected Gaussian particle beams. The weakness of the preselection step is shown to compete with the nonorthogonality of postselection in a transparent way. The approach is shown to be useful in analyzing postselection-based signal amplification, allowing measurements to be extended far beyond the range of validity of the well-known Aharonov-Albert-Vaidman limit. Additionally, the present treatment connects postselected weak measurement to the topic of phase-contrast microscopy.

  17. A simulating analysis of the effects of increased joint stiffness on muscle loading in a thumb

    PubMed Central

    2009-01-01

    Background The development of osteoarthritis (OA) in the hand results in increased joint stiffness, which in turn affects the grip strength. The goal of the present study is to theoretically analyze the muscle forces in a thumb in response to the increased joint stiffness. Methods The thumb was modeled as a linkage system consisting of a trapezium, a metacarpal bone, a proximal and a distal phalanx. Nine muscles were included in the model: flexor pollicis longus (FPL), extensor pollicis longus (EPL), extensor pollicis brevis (EPB), abductor pollicis longus (APL), flexor pollicis brevis (FPB), abductor pollicis brevis (APB), the transverse head of the adductor pollicis (ADPt), the oblique head of the adductor pollicis (ADPo), and opponens pollicis (OPP). Numerical tests were performed using an inverse dynamic approach. The joints were prescribed to an angular motion at one degree-of-freedom (DOF) each time with all other DOFs of the joints being mechanically constrained, while the muscle forces in response to the joint motions were predicted. The normal joint stiffness was assumed to be 0.05, 0.10, and 0.15 N m/rad for interphalangeal (IP), metacarpophalangeal (MCP), and carpometacarpal (CMC) joint, respectively. The joint stiffness was assumed to increase by 50% and 100%, simulating the biomechanical consequences of OA. Results Our simulations indicated that the increase in joint stiffness induced substantial increases in muscle forces, especially in the EPL and FPL muscles in response to IP, MCP, or CMC extension/flexion motions. Conclusions Because the strength of the muscles in the fingers is limited, the muscles will not be able to overcome joint resistance if joint stiffness is increased to its limit due to OA. This may contribute to the reduced range of motion typically seen in OA. PMID:20015378

  18. Simple and complex models for studying muscle function in walking.

    PubMed

    Pandy, Marcus G

    2003-09-29

    While simple models can be helpful in identifying basic features of muscle function, more complex models are needed to discern the functional roles of specific muscles in movement. In this paper, two very different models of walking, one simple and one complex, are used to study how muscle forces, gravitational forces and centrifugal forces (i.e. forces arising from motion of the joints) combine to produce the pattern of force exerted on the ground. Both the simple model and the complex one predict that muscles contribute significantly to the ground force pattern generated in walking; indeed, both models show that muscle action is responsible for the appearance of the two peaks in the vertical force. The simple model, an inverted double pendulum, suggests further that the first and second peaks are due to net extensor muscle moments exerted about the knee and ankle, respectively. Analyses based on a much more complex, muscle-actuated simulation of walking are in general agreement with these results; however, the more detailed model also reveals that both the hip extensor and hip abductor muscles contribute significantly to vertical motion of the centre of mass, and therefore to the appearance of the first peak in the vertical ground force, in early single-leg stance. This discrepancy in the model predictions is most probably explained by the difference in model complexity. First, movements of the upper body in the sagittal plane are not represented properly in the double-pendulum model, which may explain the anomalous result obtained for the contribution of a hip-extensor torque to the vertical ground force. Second, the double-pendulum model incorporates only three of the six major elements of walking, whereas the complex model is fully 3D and incorporates all six gait determinants. In particular, pelvic list occurs primarily in the frontal plane, so there is the potential for this mechanism to contribute significantly to the vertical ground force, especially

  19. Simple and complex models for studying muscle function in walking.

    PubMed Central

    Pandy, Marcus G

    2003-01-01

    While simple models can be helpful in identifying basic features of muscle function, more complex models are needed to discern the functional roles of specific muscles in movement. In this paper, two very different models of walking, one simple and one complex, are used to study how muscle forces, gravitational forces and centrifugal forces (i.e. forces arising from motion of the joints) combine to produce the pattern of force exerted on the ground. Both the simple model and the complex one predict that muscles contribute significantly to the ground force pattern generated in walking; indeed, both models show that muscle action is responsible for the appearance of the two peaks in the vertical force. The simple model, an inverted double pendulum, suggests further that the first and second peaks are due to net extensor muscle moments exerted about the knee and ankle, respectively. Analyses based on a much more complex, muscle-actuated simulation of walking are in general agreement with these results; however, the more detailed model also reveals that both the hip extensor and hip abductor muscles contribute significantly to vertical motion of the centre of mass, and therefore to the appearance of the first peak in the vertical ground force, in early single-leg stance. This discrepancy in the model predictions is most probably explained by the difference in model complexity. First, movements of the upper body in the sagittal plane are not represented properly in the double-pendulum model, which may explain the anomalous result obtained for the contribution of a hip-extensor torque to the vertical ground force. Second, the double-pendulum model incorporates only three of the six major elements of walking, whereas the complex model is fully 3D and incorporates all six gait determinants. In particular, pelvic list occurs primarily in the frontal plane, so there is the potential for this mechanism to contribute significantly to the vertical ground force, especially

  20. Aperiodic Weak Topological Superconductors

    NASA Astrophysics Data System (ADS)

    Fulga, I. C.; Pikulin, D. I.; Loring, T. A.

    2016-06-01

    Weak topological phases are usually described in terms of protection by the lattice translation symmetry. Their characterization explicitly relies on periodicity since weak invariants are expressed in terms of the momentum-space torus. We prove the compatibility of weak topological superconductors with aperiodic systems, such as quasicrystals. We go beyond usual descriptions of weak topological phases and introduce a novel, real-space formulation of the weak invariant, based on the Clifford pseudospectrum. A nontrivial value of this index implies a nontrivial bulk phase, which is robust against disorder and hosts localized zero-energy modes at the edge. Our recipe for determining the weak invariant is directly applicable to any finite-sized system, including disordered lattice models. This direct method enables a quantitative analysis of the level of disorder the topological protection can withstand.

  1. Aperiodic Weak Topological Superconductors.

    PubMed

    Fulga, I C; Pikulin, D I; Loring, T A

    2016-06-24

    Weak topological phases are usually described in terms of protection by the lattice translation symmetry. Their characterization explicitly relies on periodicity since weak invariants are expressed in terms of the momentum-space torus. We prove the compatibility of weak topological superconductors with aperiodic systems, such as quasicrystals. We go beyond usual descriptions of weak topological phases and introduce a novel, real-space formulation of the weak invariant, based on the Clifford pseudospectrum. A nontrivial value of this index implies a nontrivial bulk phase, which is robust against disorder and hosts localized zero-energy modes at the edge. Our recipe for determining the weak invariant is directly applicable to any finite-sized system, including disordered lattice models. This direct method enables a quantitative analysis of the level of disorder the topological protection can withstand. PMID:27391744

  2. Partial muscle carnitine palmitoyltransferase-A deficiency

    SciTech Connect

    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.

  3. Influence of Lateral Muscle Loading in the Proximal Femur after Fracture Stabilization with a Trochanteric Gamma Nail (TGN)

    NASA Astrophysics Data System (ADS)

    Sitthiseripratip, Kriskrai; Mahaisavariya, Banchong; Suwanprateeb, Jintamai; Bohez, Erik; Vander Sloten, Jos

    The purpose of this study was to investigate the influence of lateral muscle loading on the stress/strain distributions of the trochanteric Gamma nail (TGN) fixation within the healed, trochanteric and subtrochanteric femoral fractures by means of a finite element method. The effect of three muscle groups, the abductors (ABD), the vastus lateralis (VL) and the iliotibial band (ITB), were investigated. The analytical results showed that addition of lateral muscle forces, iliotibial band and vastus lateralis, produced compensation of forces and reduction of bending moments in the bone and in the trochanteric Gamma nail especially in the lateral aspect. The iliotibial band produced a higher impact as compared to the vastus lateralis. Therefore in the finite element analysis of the proximal femur with the trochanteric Gamma nail fracture fixation should include the lateral muscle forces to simulate load condition with maximal physiological relevance to the closed nailing technique.

  4. The syndrome of continuous muscle fibre activity following gold therapy.

    PubMed

    Grisold, W; Mamoli, B

    1984-01-01

    A 72-year-old man suffering from arthritis received a total dose of 500 mg sodium aurothiomalate during a period of 5 months. His clinical state then deteriorated and he had to be hospitalized. Upon admission he was bedridden, his level of consciousness was slightly impaired, he was confused and respiration was laboured. Continuous muscle activity was noted on all extremities and at first, erroneously, fasciculations were diagnosed. The EMG exhibited continuous muscle fibre activity consisting of duplets, triplets and multiplets. The discharges occurred in an irregular pattern; when various muscles were examined at the same time no synchronicity could be observed between muscle discharges. In the left m. deltoideus an increased percentage of polyphasic potentials was found, whereas mean duration of motor unit potentials was normal. Spontaneous activity remained unchanged during sleep and administration of intravenous diazepam or phenytoin. Blocking of ulnar nerve at either elbow or wrist level did not stop spontaneous activity in m. abductor digiti quinti. Ischaemia increased the amount of discharges after 7 min. Within 4 months after termination of gold therapy the patient's condition improved and he was discharged from hospital. Regular EMG follow-up after 8 months showed complete cessation of abnormal spontaneous activities. Nerve conduction velocities were normal except for markedly reduced compound action potential in peroneal nerves. Continuous muscle fibre activity as a side-effect of gold therapy is described. PMID:6440953

  5. Primary Motor Cortex Representation of Handgrip Muscles in Patients with Leprosy

    PubMed Central

    Rangel, Maria Luíza Sales; Sanchez, Tiago Arruda; Moreira, Filipe Azaline; Hoefle, Sebastian; Souto, Inaiacy Bittencourt; da Cunha, Antônio José Ledo Alves

    2015-01-01

    Background Leprosy is an endemic infectious disease caused by Mycobacterium leprae that predominantly attacks the skin and peripheral nerves, leading to progressive impairment of motor, sensory and autonomic function. Little is known about how this peripheral neuropathy affects corticospinal excitability of handgrip muscles. Our purpose was to explore the motor cortex organization after progressive peripheral nerve injury and upper-limb dysfunction induced by leprosy using noninvasive transcranial magnetic stimulation (TMS). Methods In a cross-sectional study design, we mapped bilaterally in the primary motor cortex (M1) the representations of the hand flexor digitorum superficialis (FDS), as well as of the intrinsic hand muscles abductor pollicis brevis (APB), first dorsal interosseous (FDI) and abductor digiti minimi (ADM). All participants underwent clinical assessment, handgrip dynamometry and motor and sensory nerve conduction exams 30 days before mapping. Wilcoxon signed rank and Mann-Whitney tests were performed with an alpha-value of p<0.05. Findings Dynamometry performance of the patients’ most affected hand (MAH), was worse than that of the less affected hand (LAH) and of healthy controls participants (p = 0.031), confirming handgrip impairment. Motor threshold (MT) of the FDS muscle was higher in both hemispheres in patients as compared to controls, and lower in the hemisphere contralateral to the MAH when compared to that of the LAH. Moreover, motor evoked potential (MEP) amplitudes collected in the FDS of the MAH were higher in comparison to those of controls. Strikingly, MEPs in the intrinsic hand muscle FDI had lower amplitudes in the hemisphere contralateral to MAH as compared to those of the LAH and the control group. Taken together, these results are suggestive of a more robust representation of an extrinsic hand flexor and impaired intrinsic hand muscle function in the hemisphere contralateral to the MAH due to leprosy. Conclusion Decreased

  6. Therapeutic approaches for muscle wasting disorders.

    PubMed

    Lynch, Gordon S; Schertzer, Jonathan D; Ryall, James G

    2007-03-01

    Muscle wasting and weakness are common in many disease states and conditions including aging, cancer cachexia, sepsis, denervation, disuse, inactivity, burns, HIV-acquired immunodeficiency syndrome (AIDS), chronic kidney or heart failure, unloading/microgravity, and muscular dystrophies. Although the maintenance of muscle mass is generally regarded as a simple balance between protein synthesis and protein degradation, these mechanisms are not strictly independent, but in fact they are coordinated by a number of different and sometimes complementary signaling pathways. Clearer details are now emerging about these different molecular pathways and the extent to which these pathways contribute to the etiology of various muscle wasting disorders. Therapeutic strategies for attenuating muscle wasting and improving muscle function vary in efficacy. Exercise and nutritional interventions have merit for slowing the rate of muscle atrophy in some muscle wasting conditions, but in most cases they cannot halt or reverse the wasting process. Hormonal and/or other drug strategies that can target key steps in the molecular pathways that regulate protein synthesis and protein degradation are needed. This review describes the signaling pathways that maintain muscle mass and provides an overview of some of the major conditions where muscle wasting and weakness are indicated. The review provides details on some therapeutic strategies that could potentially attenuate muscle atrophy, promote muscle growth, and ultimately improve muscle function. The emphasis is on therapies that can increase muscle mass and improve functional outcomes that will ultimately lead to improvement in the quality of life for affected patients. PMID:17258813

  7. Weak measure expansive flows

    NASA Astrophysics Data System (ADS)

    Lee, Keonhee; Oh, Jumi

    2016-01-01

    A notion of measure expansivity for flows was introduced by Carrasco-Olivera and Morales in [3] as a generalization of expansivity, and they proved that there were no measure expansive flows on closed surfaces. In this paper we introduce a concept of weak measure expansivity for flows which is really weaker than that of measure expansivity, and show that there is a weak measure expansive flow on a closed surface. Moreover we show that any C1 stably weak measure expansive flow on a C∞ closed manifold M is Ω-stable, and any C1 stably measure expansive flow on M satisfies both Axiom A and the quasi-transversality condition.

  8. Assessment of muscle mass and strength in mice

    PubMed Central

    Bonetto, Andrea; Andersson, Daniel C; Waning, David L

    2015-01-01

    Muscle weakness is an important phenotype of many diseases that is linked to impaired locomotion and increased mortality. The force that a muscle can generate is determined predominantly by muscle size, fiber type and the excitation–contraction coupling process. Here we describe methods for the histological assessment of whole muscle to determine fiber cross-sectional area and fiber type, determination of changes in myocyte size using C2C12 cells, in vivo functional tests and measurement of contractility in dissected whole muscles. The extensor digitorum longus and soleus muscles are ideally suited for whole-muscle contractility, and dissection of these muscles is described. PMID:26331011

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

    PubMed

    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.

  10. Intrinsic foot muscles have the capacity to control deformation of the longitudinal arch.

    PubMed

    Kelly, Luke A; Cresswell, Andrew G; Racinais, Sebastien; Whiteley, Rodney; Lichtwark, Glen

    2014-04-01

    The human foot is characterized by a pronounced longitudinal arch (LA) that compresses and recoils in response to external load during locomotion, allowing for storage and return of elastic energy within the passive structures of the arch and contributing to metabolic energy savings. Here, we examine the potential for active muscular contribution to the biomechanics of arch deformation and recoil. We test the hypotheses that activation of the three largest plantar intrinsic foot muscles, abductor hallucis, flexor digitorum and quadratus plantae is associated with muscle stretch in response to external load on the foot and that activation of these muscles (via electrical stimulation) will generate sufficient force to counter the deformation of LA caused by the external load. We found that recruitment of the intrinsic foot muscles increased with increasing load, beyond specific load thresholds. Interestingly, LA deformation and muscle stretch plateaued towards the maximum load of 150% body weight, when muscle activity was greatest. Electrical stimulation of the plantar intrinsic muscles countered the deformation that occurred owing to the application of external load by reducing the length and increasing the height of the LA. These findings demonstrate that these muscles have the capacity to control foot posture and LA stiffness and may provide a buttressing effect during foot loading. This active arch stiffening mechanism may have important implications for how forces are transmitted during locomotion and postural activities as well as consequences for metabolic energy saving.

  11. Intrinsic foot muscles have the capacity to control deformation of the longitudinal arch

    PubMed Central

    Kelly, Luke A.; Cresswell, Andrew G.; Racinais, Sebastien; Whiteley, Rodney; Lichtwark, Glen

    2014-01-01

    The human foot is characterized by a pronounced longitudinal arch (LA) that compresses and recoils in response to external load during locomotion, allowing for storage and return of elastic energy within the passive structures of the arch and contributing to metabolic energy savings. Here, we examine the potential for active muscular contribution to the biomechanics of arch deformation and recoil. We test the hypotheses that activation of the three largest plantar intrinsic foot muscles, abductor hallucis, flexor digitorum and quadratus plantae is associated with muscle stretch in response to external load on the foot and that activation of these muscles (via electrical stimulation) will generate sufficient force to counter the deformation of LA caused by the external load. We found that recruitment of the intrinsic foot muscles increased with increasing load, beyond specific load thresholds. Interestingly, LA deformation and muscle stretch plateaued towards the maximum load of 150% body weight, when muscle activity was greatest. Electrical stimulation of the plantar intrinsic muscles countered the deformation that occurred owing to the application of external load by reducing the length and increasing the height of the LA. These findings demonstrate that these muscles have the capacity to control foot posture and LA stiffness and may provide a buttressing effect during foot loading. This active arch stiffening mechanism may have important implications for how forces are transmitted during locomotion and postural activities as well as consequences for metabolic energy saving. PMID:24478287

  12. History of Weak Interactions

    DOE R&D Accomplishments Database

    Lee, T. D.

    1970-07-01

    While the phenomenon of beta-decay was discovered near the end of the last century, the notion that the weak interaction forms a separate field of physical forces evolved rather gradually. This became clear only after the experimental discoveries of other weak reactions such as muon-decay, muon-capture, etc., and the theoretical observation that all these reactions can be described by approximately the same coupling constant, thus giving rise to the notion of a universal weak interaction. Only then did one slowly recognize that the weak interaction force forms an independent field, perhaps on the same footing as the gravitational force, the electromagnetic force, and the strong nuclear and sub-nuclear forces.

  13. Amyloidotic muscle pseudohypertrophy: case report.

    PubMed

    Scola, R H; Werneck, L C; Ramos, C S; Pasquini, R; Graf, H; Arruda, W O

    2001-09-01

    The authors report one case of amyloidosis associated with muscular pseudohypertrophy in a 46-year-old woman, who developed weakness, macroglossia and muscle hypertrophy associated with primary systemic amyloidosis. Electromyography showed a myopathic pattern and bilateral carpal tunnel syndrome. The muscle biopsy presented with a type I and II fiber hypertrophy and infiltration of amyloid material in the interstitious space and artery walls. She underwent bone marrow transplantation with stabilization and subjective improvement of the clinical picture.

  14. Quality Control of Motor Unit Number Index (MUNIX) Measurements in 6 Muscles in a Single-Subject “Round-Robin” Setup

    PubMed Central

    Neuwirth, Christoph; Burkhardt, Christian; Alix, James; Castro, José; de Carvalho, Mamede; Gawel, Malgorzata; Goedee, Stephan; Grosskreutz, Julian; Lenglet, Timothée; Moglia, Cristina; Omer, Taha; Schrooten, Maarten; Weber, Markus

    2016-01-01

    Background Motor Unit Number Index (MUNIX) is a neurophysiological measure that provides an index of the number of lower motor neurons in a muscle. Its performance across centres in healthy subjects and patients with Amyotrophic Lateral Sclerosis (ALS) has been established, but inter-rater variability between multiple raters in one single subject has not been investigated. Objective To assess reliability in a set of 6 muscles in a single subject among 12 examiners (6 experienced with MUNIX, 6 less experienced) and to determine variables associated with variability of measurements. Methods Twelve raters applied MUNIX in six different muscles (abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB), tibialis anterior (TA), extensor dig. brevis (EDB), abductor hallucis (AH)) twice in one single volunteer on consecutive days. All raters visited at least one training course prior to measurements. Intra- and inter-rater variability as determined by the coefficient of variation (COV) between different raters and their levels of experience with MUNIX were compared. Results Mean intra-rater COV of MUNIX was 14.0% (±6.4) ranging from 5.8 (APB) to 30.3% (EDB). Mean inter-rater COV was 18.1 (±5.4) ranging from 8.0 (BB) to 31.7 (AH). No significant differences of variability between experienced and less experienced raters were detected. Conclusion We provide evidence that quality control for neurophysiological methods can be performed with similar standards as in laboratory medicine. Intra- and inter-rater variability of MUNIX is muscle-dependent and mainly below 20%. Experienced neurophysiologists can easily adopt MUNIX and adequate teaching ensures reliable utilization of this method. PMID:27135747

  15. Modeling Muscles

    ERIC Educational Resources Information Center

    Goodwyn, Lauren; Salm, Sarah

    2007-01-01

    Teaching the anatomy of the muscle system to high school students can be challenging. Students often learn about muscle anatomy by memorizing information from textbooks or by observing plastic, inflexible models. Although these mediums help students learn about muscle placement, the mediums do not facilitate understanding regarding integration of…

  16. Weak bond screening system

    NASA Astrophysics Data System (ADS)

    Chuang, S. Y.; Chang, F. H.; Bell, J. R.

    Consideration is given to the development of a weak bond screening system which is based on the utilization of a high power ultrasonic (HPU) technique. The instrumentation of the prototype bond strength screening system is described, and the adhesively bonded specimens used in the system developmental effort are detailed. Test results obtained from these specimens are presented in terms of bond strength and level of high power ultrasound irradiation. The following observations were made: (1) for Al/Al specimens, 2.6 sec of HPU irradiation will screen weak bond conditions due to improper preparation of bonding surfaces; (2) for composite/composite specimens, 2.0 sec of HPU irradiation will disrupt weak bonds due to under-cured conditions; (3) for Al honeycomb core with composite skin structure, 3.5 sec of HPU irradiation will disrupt weak bonds due to bad adhesive or oils contamination of bonding surfaces; and (4) for Nomex honeycomb with Al skin structure, 1.3 sec of HPU irradiation will disrupt weak bonds due to bad adhesive.

  17. Weak shock reflection

    NASA Astrophysics Data System (ADS)

    Hunter, John K.; Brio, Moysey

    2000-05-01

    We present numerical solutions of a two-dimensional inviscid Burgers equation which provides an asymptotic description of the Mach reflection of weak shocks. In our numerical solutions, the incident, reflected, and Mach shocks meet at a triple point, and there is a supersonic patch behind the triple point, as proposed by Guderley for steady weak-shock reflection. A theoretical analysis indicates that there is an expansion fan at the triple point, in addition to the three shocks. The supersonic patch is extremely small, and this work is the first time it has been resolved.

  18. Upper Limb Strength and Muscle Volume in Healthy Middle-Aged Adults.

    PubMed

    Saul, Katherine R; Vidt, Meghan E; Gold, Garry E; Murray, Wendy M

    2015-12-01

    Our purpose was to characterize shoulder muscle volume and isometric moment, as well as their relationship, for healthy middle- aged adults. Muscle volume and maximum isometric joint moment were assessed for 6 functional muscle groups of the shoulder, elbow, and wrist in 10 middle-aged adults (46–60 y, 5M, 5F). Compared with young adults, shoulder abductors composed a smaller percentage of total muscle volume (P = .0009) and there was a reduction in shoulder adductor strength relative to elbow flexors (P = .012). We observed a consistent ordering of moment-generating capacity among functional groups across subjects. Although total muscle volume spanned a 2.3-fold range, muscle volume was distributed among functional groups in a consistent manner across subjects. On average, 72% of the variation in joint moment could be explained by the corresponding functional group muscle volume. These data are useful for improved modeling of upper limb musculoskeletal performance in middle-aged subjects, and may improve computational predictions of function for this group. PMID:26155870

  19. Functional Electrical Stimulation of Intrinsic Laryngeal Muscles under Varying Loads in Exercising Horses

    PubMed Central

    Cheetham, Jon; Regner, Abby; Jarvis, Jonathan C.; Priest, David; Sanders, Ira; Soderholm, Leo V.; Mitchell, Lisa M.; Ducharme, Norm G.

    2011-01-01

    Bilateral vocal fold paralysis (BVCP) is a life threatening condition and appears to be a good candidate for therapy using functional electrical stimulation (FES). Developing a working FES system has been technically difficult due to the inaccessible location and small size of the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle. A naturally-occurring disease in horses shares many functional and etiological features with BVCP. In this study, the feasibility of FES for equine vocal fold paralysis was explored by testing arytenoid abduction evoked by electrical stimulation of the PCA muscle. Rheobase and chronaxie were determined for innervated PCA muscle. We then tested the hypothesis that direct muscle stimulation can maintain airway patency during strenuous exercise in horses with induced transient conduction block of the laryngeal motor nerve. Six adult horses were instrumented with a single bipolar intra-muscular electrode in the left PCA muscle. Rheobase and chronaxie were within the normal range for innervated muscle at 0.55±0.38 v and 0.38±0.19 ms respectively. Intramuscular stimulation of the PCA muscle significantly improved arytenoid abduction at all levels of exercise intensity and there was no significant difference between the level of abduction achieved with stimulation and control values under moderate loads. The equine larynx may provide a useful model for the study of bilateral fold paralysis. PMID:21904620

  20. The Effects of a Transition to Minimalist Shoe Running on Intrinsic Foot Muscle Size.

    PubMed

    Johnson, A W; Myrer, J W; Mitchell, U H; Hunter, I; Ridge, S T

    2016-02-01

    A proposed benefit of minimalist shoe running is an increase in intrinsic foot muscle strength. This study examined change in intrinsic foot muscle size in runners transitioning to Vibram FiveFingers™ minimalist shoes compared to a control group running in traditional running shoes. We compare pre-transition size between runners who developed bone marrow edema to those who did not. 37 runners were randomly assigned to the Vibram FiveFingers™ group (n=18) or control group (n=19). Runners' bone marrow edema and intrinsic foot muscle size were measured at baseline and after 10 weeks. Total running volume was maintained by all runners. A significant increase in abductor hallucis cross-sectional area of 10.6% occurred in the Vibram FiveFingers™ group compared to the control group (p=0.01). There was no significant change in any of the other muscles examined (p>0.05). 8 of the Vibram FiveFingers™ runners, and 1 control runner developed bone marrow edema. Those who developed bone marrow edema, primarily women, had significantly smaller size in all assessed muscles (p≤0.05). Size of intrinsic foot muscles appears to be important in safely transitioning to minimalist shoe running. Perhaps intrinsic foot muscle strengthening may benefit runners wanting to transition to minimalist shoes.

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

    PubMed

    Cheetham, Jon; Regner, Abby; Jarvis, Jonathan C; Priest, David; Sanders, Ira; Soderholm, Leo V; Mitchell, Lisa M; Ducharme, Norm G

    2011-01-01

    Bilateral vocal fold paralysis (BVCP) is a life threatening condition and appears to be a good candidate for therapy using functional electrical stimulation (FES). Developing a working FES system has been technically difficult due to the inaccessible location and small size of the sole arytenoid abductor, the posterior cricoarytenoid (PCA) muscle. A naturally-occurring disease in horses shares many functional and etiological features with BVCP. In this study, the feasibility of FES for equine vocal fold paralysis was explored by testing arytenoid abduction evoked by electrical stimulation of the PCA muscle. Rheobase and chronaxie were determined for innervated PCA muscle. We then tested the hypothesis that direct muscle stimulation can maintain airway patency during strenuous exercise in horses with induced transient conduction block of the laryngeal motor nerve. Six adult horses were instrumented with a single bipolar intra-muscular electrode in the left PCA muscle. Rheobase and chronaxie were within the normal range for innervated muscle at 0.55±0.38 v and 0.38±0.19 ms respectively. Intramuscular stimulation of the PCA muscle significantly improved arytenoid abduction at all levels of exercise intensity and there was no significant difference between the level of abduction achieved with stimulation and control values under moderate loads. The equine larynx may provide a useful model for the study of bilateral fold paralysis. PMID:21904620

  2. Episodic weakness and vacuolar myopathy in hypokalemic periodic paralysis.

    PubMed

    Basali, Diana; Prayson, Richard A

    2015-11-01

    We report a 50-year-old woman who presented with a 20 year history of gradually progressive lower extremity weakness, characterized by knee buckling with occasional falls and foot dragging. She also experienced difficulty in lifting her arms above her shoulders. The primary periodic paralyses are rare disorders caused by dysfunctional ion channels in skeletal muscle. The hypokalemic type is generally an autosomal dominant condition, due to missense mutations in the alpha subunits of the skeletal muscle L-type calcium channel genes, CACN1AS, or the skeletal muscle sodium channel gene, SCN4A. The affected patients typically present with episodic weakness. For our patient, the consumption of foods high in carbohydrates seemed to precipitate the episodes of weakness. Her family history was significant for six blood relatives, including three sons and three relatives on the paternal side, who had experienced similar symptoms. A biopsy of the left rectus femoralis muscle showed vacuolar myopathic changes in the scattered muscle fibers, accompanied by occasional degenerating and regenerating muscle fibers. There was no evidence of inflammation on the biopsy. The vacuoles were often associated with increased acid phosphatase staining. An electron microscopic examination showed that the vacuolar changes were due to T-tubule dilation, a characteristic of hypokalemic periodic paralysis. Other metabolic etiologies of vacuolar myopathy, such as acid phosphatase (lysosomal) associated acid maltase deficiency (a glycogen storage disease), need to be considered in the differential diagnosis. PMID:26190219

  3. Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter

    PubMed Central

    MORI, Kent; SUZUKI, Satoshi; KOYABU, Daisuke; KIMURA, Junpei; HAN, Sung-Yong; ENDO, Hideki

    2015-01-01

    Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids. PMID:25715875

  4. Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter.

    PubMed

    Mori, Kent; Suzuki, Satoshi; Koyabu, Daisuke; Kimura, Junpei; Han, Sung-Yong; Endo, Hideki

    2015-05-01

    Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids.

  5. Comparative functional anatomy of hindlimb muscles and bones with reference to aquatic adaptation of the sea otter.

    PubMed

    Mori, Kent; Suzuki, Satoshi; Koyabu, Daisuke; Kimura, Junpei; Han, Sung-Yong; Endo, Hideki

    2015-05-01

    Although the sea otter (Enhydra lutris) is a complete aquatic species, spending its entire life in the ocean, it has been considered morphologically to be a semi-aquatic animal. This study aimed to clarify the unique hindlimb morphology and functional adaptations of E. lutris in comparison to other Mustelidae species. We compared muscle mass and bone measurements of five Mustelidae species: the sea otter, Eurasian river otter (Lutra lutra), American mink (Neovison vison), Japanese weasel (Mustela itatsi) and Siberian weasel (M. sibirica). In comparison with the other 4 species, E. lutris possessed significantly larger gluteus, popliteus and peroneus muscles, but smaller adductor and ischiopubic muscles. The popliteus muscle may act as a medial rotator of the crus, and the peroneus muscle may act as an abductor of the fifth toe and/or the pronator of the foot. The bundles of the gluteus superficialis muscle of E. lutris were fused with those of the tensor fasciae latae muscle and gluteofemoralis muscles, and they may play a role in femur abduction. These results suggest that E. lutris uses the abducted femur, medially rotated crus, eversion of the ankle and abducted fifth digit or extended interdigital web as a powerful propulsion generator. Therefore, we conclude that E. lutris is a complete aquatic animal, possessing differences in the proportions of the hindlimb muscles compared with those in other semi-aquatic and terrestrial mustelids. PMID:25715875

  6. In praise of weakness

    NASA Astrophysics Data System (ADS)

    Steinberg, Aephraim; Feizpour, Amir; Rozema; Mahler; Hayat

    2013-03-01

    Quantum physics is being transformed by a radical new conceptual and experimental approach known as weak measurement that can do everything from tackling basic quantum mysteries to mapping the trajectories of photons in a Young's double-slit experiment. Aephraim Steinberg, Amir Feizpour, Lee Rozema, Dylan Mahler and Alex Hayat unveil the power of this new technique.

  7. Clinical Implications for Muscle Strength Differences in Women of Different Age and Racial Groups: The WIN Study

    PubMed Central

    Trudelle-Jackson, Elaine; Ferro, Emerenciana; Morrow, James R.

    2011-01-01

    Background Reduction in muscle strength is strongly associated with functional decline in women, and women with lower quadriceps strength adjusted for body weight are more likely to develop knee osteoarthritis. Objective To compare body weight--adjusted strength among women of different age/racial groups. Study Design Cross-sectional study of muscle strength in 918 women aged 20--83 (M ± SD = 52 ± 13). Methods An orthopedic examination was conducted including measurement of handgrip and lower extremity strength (hip abductors/external rotators, knee flexors/extensors). Data were grouped into young (20--39 years, n = 139), middle (40--54 years, n = 300), and older (55+ years, n = 424) ages for white (n = 699) and African American (AA) (n = 164) women. Means and standard deviations for strength adjusted for body weight were calculated for each age and racial group and compared using 2-way multivariate analysis of variance and post hoc tests. Results No significant age-by-race interaction (P = .092) but significant main effects for age and race (P < .001). Pairwise comparisons revealed significant differences in knee extensor and flexor strength between all age groups. For grip and hip external rotator strength, significant differences were found between the middle and older groups. Differences in hip abductor strength were found between the young and middle-aged groups. AA women had lower strength than white women in all muscle groups (P < .05) except hip external rotators. Conclusions Strength decreased with age in all muscle groups but magnitude of decrease varied by muscle. Strengthening programs should target different muscles, depending on a woman's age and race. PMID:21666779

  8. Hypernuclear Weak Decays

    NASA Astrophysics Data System (ADS)

    Itonaga, K.; Motoba, T.

    The recent theoretical studies of Lambda-hypernuclear weak decaysof the nonmesonic and pi-mesonic ones are developed with the aim to disclose the link between the experimental decay observables and the underlying basic weak decay interactions and the weak decay mechanisms. The expressions of the nonmesonic decay rates Gamma_{nm} and the decay asymmetry parameter alpha_1 of protons from the polarized hypernuclei are presented in the shell model framework. We then introduce the meson theoretical Lambda N -> NN interactions which include the one-meson exchanges, the correlated-2pi exchanges, and the chiral-pair-meson exchanges. The features of meson exchange potentials and their roles on the nonmesonic decays are discussed. With the adoption of the pi + 2pi/rho + 2pi/sigma + omega + K + rhopi/a_1 + sigmapi/a_1 exchange potentials, we have carried out the systematic calculations of the nonmesonic decay observables for light-to-heavy hypernuclei. The present model can account for the available experimental data of the decay rates, Gamma_n/Gamma_p ratios, and the intrinsic asymmetry parameters alpha_Lambda (alpha_Lambda is related to alpha_1) of emitted protons well and consistently within the error bars. The hypernuclear lifetimes are evaluated by converting the total weak decay rates Gamma_{tot} = Gamma_pi + Gamma_{nm} to tau, which exhibit saturation property for the hypernuclear mass A ≥ 30 and agree grossly well with experimental data for the mass range from light to heavy hypernuclei except for the very light ones. Future extensions of the model and the remaining problems are also mentioned. The pi-mesonic weak processes are briefly surveyed, and the calculations and predictions are compared and confirmed by the recent high precision FINUDA pi-mesonic decay data. This shows that the theoretical basis seems to be firmly grounded.

  9. Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders

    PubMed Central

    Fang, Jia; Liu, Ming-Sheng; Guan, Yu-Zhou; Du, Hua; Li, Ben-Hong; Cui, Bo; Ding, Qing-Yun; Cui, Li-Ying

    2016-01-01

    Background: Amyotrophic lateral sclerosis (ALS) and some mimic disorders, such as distal-type cervical spondylotic amyotrophy (CSA), Hirayama disease (HD), and spinobulbar muscular atrophy (SBMA) may present with intrinsic hand muscle atrophy. This study aimed to investigate different patterns of small hand muscle involvement in ALS and some mimic disorders. Methods: We compared the abductor digiti minimi/abductor pollicis brevis (ADM/APB) compound muscle action potential (CMAP) ratios between 200 ALS patients, 95 patients with distal-type CSA, 88 HD patients, 43 SBMA patients, and 150 normal controls. Results: The ADM/APB CMAP amplitude ratio was significantly higher in the ALS patients (P < 0.001) than that in the normal controls. The ADM/APB CMAP amplitude ratio was significantly reduced in the patients with distal-type CSA (P < 0.001) and the HD patients (P < 0.001) compared with that in the normal controls. The patients with distal-type CSA had significantly lower APB CMAP amplitude than the HD patients (P = 0.004). The ADM/APB CMAP amplitude ratio was significantly lower in the HD patients (P < 0.001) than that in the patients with distal-type CSA. The ADM/APB CMAP amplitude ratio of the SBMA patients was similar to that of the normal controls (P = 0.862). An absent APB CMAP and an abnormally high ADM/APB CMAP amplitude ratio (≥4.5) were observed exclusively in the ALS patients. Conclusions: The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders, and may aid in distinguishing between ALS and mimic disorders. PMID:26996473

  10. Atypical presentation of GNE myopathy with asymmetric hand weakness.

    PubMed

    de Dios, John Karl L; Shrader, Joseph A; Joe, Galen O; McClean, Jeffrey C; Williams, Kayla; Evers, Robert; Malicdan, May Christine V; Ciccone, Carla; Mankodi, Ami; Huizing, Marjan; McKew, John C; Bluemke, David A; Gahl, William A; Carrillo-Carrasco, Nuria

    2014-12-01

    GNE myopathy is a rare autosomal recessive muscle disease caused by mutations in GNE, the gene encoding the rate-limiting enzyme in sialic acid biosynthesis. GNE myopathy usually manifests in early adulthood with distal myopathy that progresses slowly and symmetrically, first involving distal muscles of the lower extremities, followed by proximal muscles with relative sparing of the quadriceps. Upper extremities are typically affected later in the disease. We report a patient with GNE myopathy who presented with asymmetric hand weakness. He had considerably decreased left grip strength, atrophy of the left anterior forearm and fibro-fatty tissue replacement of left forearm flexor muscles on T1-weighted magnetic resonance imaging. The patient was an endoscopist and thus the asymmetric hand involvement may be associated with left hand overuse in daily repetitive pinching and gripping movements, highlighting the possible impact of environmental factors on the progression of genetic muscle conditions. PMID:25182749

  11. Atypical presentation of GNE myopathy with asymmetric hand weakness.

    PubMed

    de Dios, John Karl L; Shrader, Joseph A; Joe, Galen O; McClean, Jeffrey C; Williams, Kayla; Evers, Robert; Malicdan, May Christine V; Ciccone, Carla; Mankodi, Ami; Huizing, Marjan; McKew, John C; Bluemke, David A; Gahl, William A; Carrillo-Carrasco, Nuria

    2014-12-01

    GNE myopathy is a rare autosomal recessive muscle disease caused by mutations in GNE, the gene encoding the rate-limiting enzyme in sialic acid biosynthesis. GNE myopathy usually manifests in early adulthood with distal myopathy that progresses slowly and symmetrically, first involving distal muscles of the lower extremities, followed by proximal muscles with relative sparing of the quadriceps. Upper extremities are typically affected later in the disease. We report a patient with GNE myopathy who presented with asymmetric hand weakness. He had considerably decreased left grip strength, atrophy of the left anterior forearm and fibro-fatty tissue replacement of left forearm flexor muscles on T1-weighted magnetic resonance imaging. The patient was an endoscopist and thus the asymmetric hand involvement may be associated with left hand overuse in daily repetitive pinching and gripping movements, highlighting the possible impact of environmental factors on the progression of genetic muscle conditions.

  12. Lifting the nebula: novel insights into skeletal muscle contractility.

    PubMed

    Ottenheijm, Coen A C; Granzier, Henk

    2010-10-01

    Nebulin is a giant protein and a constituent of the skeletal muscle sarcomere. The name of this protein refers to its unknown (i.e., nebulous) function. However, recent rapid advances reveal that nebulin plays important roles in the regulation of muscle contraction. When these functions of nebulin are compromised, muscle weakness ensues, as is the case in patients with nemaline myopathy. PMID:20940435

  13. Weak Gravitational Lensing

    NASA Astrophysics Data System (ADS)

    Pires, Sandrine; Starck, Jean-Luc; Leonard, Adrienne; Réfrégier, Alexandre

    2012-03-01

    This chapter reviews the data mining methods recently developed to solve standard data problems in weak gravitational lensing. We detail the different steps of the weak lensing data analysis along with the different techniques dedicated to these applications. An overview of the different techniques currently used will be given along with future prospects. Until about 30 years ago, astronomers thought that the Universe was composed almost entirely of ordinary matter: protons, neutrons, electrons, and atoms. The field of weak lensing has been motivated by the observations made in the last decades showing that visible matter represents only about 4-5% of the Universe (see Figure 14.1). Currently, the majority of the Universe is thought to be dark, that is, does not emit electromagnetic radiation. The Universe is thought to be mostly composed of an invisible, pressure less matter - potentially relic from higher energy theories - called "dark matter" (20-21%) and by an even more mysterious term, described in Einstein equations as a vacuum energy density, called "dark energy" (70%). This "dark" Universe is not well described or even understood; its presence is inferred indirectly from its gravitational effects, both on the motions of astronomical objects and on light propagation. So this point could be the next breakthrough in cosmology. Today's cosmology is based on a cosmological model that contains various parameters that need to be determined precisely, such as the matter density parameter Omega_m or the dark energy density parameter Omega_lambda. Weak gravitational lensing is believed to be the most promising tool to understand the nature of dark matter and to constrain the cosmological parameters used to describe the Universe because it provides a method to directly map the distribution of dark matter (see [1,6,60,63,70]). From this dark matter distribution, the nature of dark matter can be better understood and better constraints can be placed on dark energy

  14. Composite weak bosons

    SciTech Connect

    Suzuki, M.

    1988-04-01

    Dynamical mechanism of composite W and Z is studied in a 1/N field theory model with four-fermion interactions in which global weak SU(2) symmetry is broken explicitly by electromagnetic interaction. Issues involved in such a model are discussed in detail. Deviation from gauge coupling due to compositeness and higher order loop corrections are examined to show that this class of models are consistent not only theoretically but also experimentally.

  15. Sequential weak measurement

    SciTech Connect

    Mitchison, Graeme; Jozsa, Richard; Popescu, Sandu |||

    2007-12-15

    The notion of weak measurement provides a formalism for extracting information from a quantum system in the limit of vanishing disturbance to its state. Here we extend this formalism to the measurement of sequences of observables. When these observables do not commute, we may obtain information about joint properties of a quantum system that would be forbidden in the usual strong measurement scenario. As an application, we provide a physically compelling characterization of the notion of counterfactual quantum computation.

  16. Late cortical disinhibition in relaxed versus active hand muscles.

    PubMed

    Caux-Dedeystère, A; Derambure, P; Devanne, H

    2015-07-01

    Recent research suggests that long-interval intracortical inhibition (LICI) is followed by a transitory period of late cortical disinhibition (LCD) that can even lead to a net increase in cortical excitability. The relationship between LICI/LCD and voluntary drive remains poorly understood. Our study aims at investigating the influence of index abduction on LICI and LCD in an actively engaged muscle and a neighboring muscle, while varying the intensity of the conditioning stimulus (CS). Motor-evoked potentials (MEPs) were recorded from the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscles in 13 subjects. Paired-pulses were delivered with 10 different interstimulus intervals (ranging from 60 to 290 ms). Whatever the condition (relaxed or active FDI), the test stimulus was set to evoke an MEP of 1mV. The time course of conditioned MEP amplitude was compared for relaxed and active conditions when the CS intensity was set to (i) 130% of the rest motor threshold (RMT) or (ii) to evoke the same size of MEP under both conditions. LICI lasted longer (i.e. disinhibition occurred later) at rest than during abduction when evoked either by similar or matched conditioning stimuli. No post-LICI facilitation was observed at rest - even when the CS intensity was set to 160% RMT. In contrast, long-interval intracortical facilitation (LICF) was observed in the quiescent ADM when FDI was active. LICF may then be associated with voluntary activity albeit with lack of topographic specificity. PMID:25888934

  17. Anomalous bilateral contribution of extensor pollicis longus and muscle fusion of the first compartment of the wrist

    PubMed Central

    Rosa, Rodrigo César; de Oliveira, Kennedy Martinez; Léo, Jorge Alfredo; Elias, Bruno Adriano Borges; dos Santos, Paulo Ricardo; de Santiago, Hildemberg Agostinho Rocha

    2016-01-01

    Knowledge of the anatomical variations of the muscles of the first dorsal compartments of the wrist is clinically relevant to De Quervain's tenosynovitis and to reconstructive surgeries. In the literature, there are many reports of the presence of multiple insertion tendons in the first dorsal compartment of the wrist, but few reports describe occurrences of fusion and muscle contributions. This case report describes an anomalous bilateral contribution of the extensor pollicis longus. This anomalous contribution was found through a slender auxiliary tendon that crossed laterally under the extensor retinaculum, entered the first dorsal compartment of the wrist and merged with the tendon of the extensor pollicis brevis muscle. In the same cadaver in which this contribution was present, there was atypical muscle fusion of the abductor pollicis longus muscle and extensor pollicis brevis muscle. In conclusion, anomalous bilateral contribution of the extensor pollicis longus muscle and atypical muscle fusion, concomitant with a variant insertion pattern, are the highlight of this case report. Furthermore, it is concluded that additional tendons may be effectively used in reconstructive surgeries, but that there is a need for knowledge of the possible numerical and positional variations of these tendons, with a view to making more effective surgical plans. PMID:27069895

  18. Contributions of muscles to mediolateral ground reaction force over a range of walking speeds.

    PubMed

    John, Chand T; Seth, Ajay; Schwartz, Michael H; Delp, Scott L

    2012-09-21

    Impaired control of mediolateral body motion during walking is an important health concern. Developing treatments to improve mediolateral control is challenging, partly because the mechanisms by which muscles modulate mediolateral ground reaction force (and thereby modulate mediolateral acceleration of the body mass center) during unimpaired walking are poorly understood. To investigate this, we examined mediolateral ground reaction forces in eight unimpaired subjects walking at four speeds and determined the contributions of muscles, gravity, and velocity-related forces to the mediolateral ground reaction force by analyzing muscle-driven simulations of these subjects. During early stance (0-6% gait cycle), peak ground reaction force on the leading foot was directed laterally and increased significantly (p<0.05) with walking speed. During early single support (14-30% gait cycle), peak ground reaction force on the stance foot was directed medially and increased significantly (p<0.01) with speed. Muscles accounted for more than 92% of the mediolateral ground reaction force over all walking speeds, whereas gravity and velocity-related forces made relatively small contributions. Muscles coordinate mediolateral acceleration via an interplay between the medial ground reaction force contributed by the abductors and the lateral ground reaction forces contributed by the knee extensors, plantarflexors, and adductors. Our findings show how muscles that contribute to forward progression and body-weight support also modulate mediolateral acceleration of the body mass center while weight is transferred from one leg to another during double support.

  19. Importance and challenges of measuring intrinsic foot muscle strength

    PubMed Central

    2012-01-01

    Background Intrinsic foot muscle weakness has been implicated in a range of foot deformities and disorders. However, to establish a relationship between intrinsic muscle weakness and foot pathology, an objective measure of intrinsic muscle strength is needed. The aim of this review was to provide an overview of the anatomy and role of intrinsic foot muscles, implications of intrinsic weakness and evaluate the different methods used to measure intrinsic foot muscle strength. Method Literature was sourced from database searches of MEDLINE, PubMed, SCOPUS, Cochrane Library, PEDro and CINAHL up to June 2012. Results There is no widely accepted method of measuring intrinsic foot muscle strength. Methods to estimate toe flexor muscle strength include the paper grip test, plantar pressure, toe dynamometry, and the intrinsic positive test. Hand-held dynamometry has excellent interrater and intrarater reliability and limits toe curling, which is an action hypothesised to activate extrinsic toe flexor muscles. However, it is unclear whether any method can actually isolate intrinsic muscle strength. Also most methods measure only toe flexor strength and other actions such as toe extension and abduction have not been adequately assessed. Indirect methods to investigate intrinsic muscle structure and performance include CT, ultrasonography, MRI, EMG, and muscle biopsy. Indirect methods often discriminate between intrinsic and extrinsic muscles, but lack the ability to measure muscle force. Conclusions There are many challenges to accurately measure intrinsic muscle strength in isolation. Most studies have measured toe flexor strength as a surrogate measure of intrinsic muscle strength. Hand-held dynamometry appears to be a promising method of estimating intrinsic muscle strength. However, the contribution of extrinsic muscles cannot be excluded from toe flexor strength measurement. Future research should clarify the relative contribution of intrinsic and extrinsic muscles

  20. The pectoral fin muscles of the coelacanth Latimeria chalumnae: Functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods.

    PubMed

    Miyake, Tsutomu; Kumamoto, Minayori; Iwata, Masamitsu; Sato, Ryuichi; Okabe, Masataka; Koie, Hiroshi; Kumai, Nori; Fujii, Kenichi; Matsuzaki, Koji; Nakamura, Chiho; Yamauchi, Shinya; Yoshida, Kosuke; Yoshimura, Kohtaroh; Komoda, Akira; Uyeno, Teruya; Abe, Yoshitaka

    2016-09-01

    To investigate the morphology and evolutionary origin of muscles in vertebrate limbs, we conducted anatomical dissections, computed tomography and kinematic analyses on the pectoral fin of the African coelacanth, Latimeria chalumnae. We discovered nine antagonistic pairs of pronators and supinators that are anatomically and functionally distinct from the abductor and adductor superficiales and profundi. In particular, the first pronator and supinator pair represents mono- and biarticular muscles; a portion of the muscle fibers is attached to ridges on the humerus and is separated into two monoarticular muscles, whereas, as a biarticular muscle, the main body is inserted into the radius by crossing two joints from the shoulder girdle. This pair, consisting of a pronator and supinator, constitutes a muscle arrangement equivalent to two human antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod between the shoulder and elbow joints. Our recent kinesiological and biomechanical engineering studies on human limbs have demonstrated that two antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod (1) coordinately control output force and force direction at the wrist and ankle and (2) achieve a contact task to carry out weight-bearing motion and maintain stable posture. Therefore, along with dissections of the pectoral fins in two lungfish species, Neoceratodus forsteri and Protopterus aethiopicus, we discuss the functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods. Anat Rec, 299:1203-1223, 2016. © 2016 Wiley Periodicals, Inc.

  1. The pectoral fin muscles of the coelacanth Latimeria chalumnae: Functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods.

    PubMed

    Miyake, Tsutomu; Kumamoto, Minayori; Iwata, Masamitsu; Sato, Ryuichi; Okabe, Masataka; Koie, Hiroshi; Kumai, Nori; Fujii, Kenichi; Matsuzaki, Koji; Nakamura, Chiho; Yamauchi, Shinya; Yoshida, Kosuke; Yoshimura, Kohtaroh; Komoda, Akira; Uyeno, Teruya; Abe, Yoshitaka

    2016-09-01

    To investigate the morphology and evolutionary origin of muscles in vertebrate limbs, we conducted anatomical dissections, computed tomography and kinematic analyses on the pectoral fin of the African coelacanth, Latimeria chalumnae. We discovered nine antagonistic pairs of pronators and supinators that are anatomically and functionally distinct from the abductor and adductor superficiales and profundi. In particular, the first pronator and supinator pair represents mono- and biarticular muscles; a portion of the muscle fibers is attached to ridges on the humerus and is separated into two monoarticular muscles, whereas, as a biarticular muscle, the main body is inserted into the radius by crossing two joints from the shoulder girdle. This pair, consisting of a pronator and supinator, constitutes a muscle arrangement equivalent to two human antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod between the shoulder and elbow joints. Our recent kinesiological and biomechanical engineering studies on human limbs have demonstrated that two antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod (1) coordinately control output force and force direction at the wrist and ankle and (2) achieve a contact task to carry out weight-bearing motion and maintain stable posture. Therefore, along with dissections of the pectoral fins in two lungfish species, Neoceratodus forsteri and Protopterus aethiopicus, we discuss the functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods. Anat Rec, 299:1203-1223, 2016. © 2016 Wiley Periodicals, Inc. PMID:27343022

  2. `Weak A' phenotypes

    PubMed Central

    Cartron, J. P.; Gerbal, A.; Hughes-Jones, N. C.; Salmon, C.

    1974-01-01

    Thirty-five weak A samples including fourteen A3, eight Ax, seven Aend, three Am and three Ae1 were studied in order to determine their A antigen site density, using an IgG anti-A labelled with 125I. The values obtained ranged between 30,000 A antigen sites for A3 individuals, and 700 sites for the Ae1 red cells. The hierarchy of values observed made it possible to establish a quantitative relationship between the red cell agglutinability of these phenotypes measured under standard conditions, and their antigen site density. PMID:4435836

  3. Weakly broken galileon symmetry

    SciTech Connect

    Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Vernizzi, Filippo

    2015-09-01

    Effective theories of a scalar ϕ invariant under the internal galileon symmetryϕ→ϕ+b{sub μ}x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon’s quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.

  4. Weak decay of hypernuclei

    SciTech Connect

    Grace, R.

    1983-01-01

    The Moby Dick spectrometer (at BNL) in coincidence with a range spectrometer and a TOF neutron detector will be used to study the weak decay modes of /sup 12/C. The Moby Dick spectrometer will be used to reconstruct and tag events in which specific hypernuclear states are formed in the reaction K/sup -/ + /sup 12/C ..-->.. ..pi../sup -/ + /sup 12/C. Subsequent emission of decay products (pions, protons and neutrons) in coincidence with the fast forward pion will be detected in a time and range spectrometer, and a neutron detector.

  5. Weakly broken galileon symmetry

    SciTech Connect

    Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Vernizzi, Filippo E-mail: luca.santoni@sns.it E-mail: filippo.vernizzi@cea.fr

    2015-09-01

    Effective theories of a scalar φ invariant under the internal galileon symmetry φ→φ+b{sub μ} x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon's quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.

  6. Changes in predicted muscle coordination with subject-specific muscle parameters for individuals after stroke.

    PubMed

    Knarr, Brian A; Reisman, Darcy S; Binder-Macleod, Stuart A; Higginson, Jill S

    2014-01-01

    Muscle weakness is commonly seen in individuals after stroke, characterized by lower forces during a maximal volitional contraction. Accurate quantification of muscle weakness is paramount when evaluating individual performance and response to after stroke rehabilitation. The objective of this study was to examine the effect of subject-specific muscle force and activation deficits on predicted muscle coordination when using musculoskeletal models for individuals after stroke. Maximum force generating ability and central activation ratio of the paretic plantar flexors, dorsiflexors, and quadriceps muscle groups were obtained using burst superimposition for four individuals after stroke with a range of walking speeds. Two models were created per subject: one with generic and one with subject-specific activation and maximum isometric force parameters. The inclusion of subject-specific muscle data resulted in changes in the model-predicted muscle forces and activations which agree with previously reported compensation patterns and match more closely the timing of electromyography for the plantar flexor and hamstring muscles. This was the first study to create musculoskeletal simulations of individuals after stroke with subject-specific muscle force and activation data. The results of this study suggest that subject-specific muscle force and activation data enhance the ability of musculoskeletal simulations to accurately predict muscle coordination in individuals after stroke.

  7. A single muscle moves a crustacean limb joint rhythmically by acting against a spring containing resilin

    PubMed Central

    Burrows, Malcolm

    2009-01-01

    Background The beating or fanning movements of three pairs of maxilliped flagella in crabs and crayfish modify exhalent gill currents while drawing water over chemoreceptors on the head. They play an integral part both in signalling by distributing urine odours, and in active chemosensation. Results The rhythmical maxilliped movements start with maxilliped 3 followed after a delay of 15 to 20 ms in shore crabs by maxilliped 2 and then maxilliped 1, at a frequency of 18 to 20 Hz in crabs and 10 to 13 Hz in signal crayfish. The contraction of a single abductor muscle controls the power stroke (abduction) of each flagellum, which is accompanied by flaring of feather-like setae which increase its surface area. No muscle can bring about the return stroke (adduction). Release of an isolated flagellum from an imposed abduction is followed by a rapid recoil to its resting adducted position. The relationship between the extent of abduction and the angular velocity of the return stroke indicates the operation of a spring. Blue fluorescence under UV light, and its dependence on the pH of the bathing medium, indicates that resilin is present at the joint between an exopodite and flagellum, at the annuli of a flagellum and at the base of the setae. Conclusion Resilin is progressively bent as a flagellum is abducted and resumes its natural shape when the joint recoils. Other distortions of the exopodites may also contribute to this spring-like action. The joint is therefore controlled by a single abductor muscle operating against a spring in which the elastic properties of resilin play a key role. PMID:19480647

  8. Botulinum toxin type A injections for the management of muscle tightness following total hip arthroplasty: a case series

    PubMed Central

    Bhave, Anil; Zywiel, Michael G; Ulrich, Slif D; McGrath, Mike S; Seyler, Thorsten M; Marker, David R; Delanois, Ronald E; Mont, Michael A

    2009-01-01

    Background Development of hip adductor, tensor fascia lata, and rectus femoris muscle contractures following total hip arthroplasties are quite common, with some patients failing to improve despite treatment with a variety of non-operative modalities. The purpose of the present study was to describe the use of and patient outcomes of botulinum toxin injections as an adjunctive treatment for muscle tightness following total hip arthroplasty. Methods Ten patients (14 hips) who had hip adductor, abductor, and/or flexor muscle contractures following total arthroplasty and had been refractory to physical therapeutic efforts were treated with injection of botulinum toxin A. Eight limbs received injections into the adductor muscle, 8 limbs received injections into the tensor fascia lata muscle, and 2 limbs received injection into the rectus femoris muscle, followed by intensive physical therapy for 6 weeks. Results At a mean final follow-up of 20 months, all 14 hips had increased range in the affected arc of motion, with a mean improvement of 23 degrees (range, 10 to 45 degrees). Additionally all hips had an improvement in hip scores, with a significant increase in mean score from 74 points (range, 57 to 91 points) prior to injection to a mean of 96 points (range, 93 to 98) at final follow-up. There were no serious treatment-related adverse events. Conclusion Botulinum toxin A injections combined with intensive physical therapy may be considered as a potential treatment modality, especially in difficult cases of muscle tightness that are refractory to standard therapy. PMID:19709429

  9. Changes in muscle activity after performing the FIFA 11+ programme part 2 for 4 weeks.

    PubMed

    Takata, Yasushi; Nakase, Junsuke; Inaki, Anri; Mochizuki, Takafumi; Numata, Hitoaki; Oshima, Takeshi; Kinuya, Seigo; Tsuchiya, Hiroyuki

    2016-10-01

    Changes in muscle activity were evaluated by positron emission tomography-computed tomography (PET-CT) after performing part 2 of the Fédération Internationale de Football Association's 11+ programme (11+) for 4 weeks. Eleven males performed part 2 of the 11+ for 20 min before and after 37 MBq of (18)F-fluorodeoxyglucose (FDG) was injected intravenously. PET-CT images were obtained 50 min after FDG injection. The participants were then instructed to perform part 2 of the 11+ 3 times per week for 4 consecutive weeks, after which another set of PET-CT images was obtained following the same procedure. Regions of interest were defined within 30 muscles. The standardised uptake value (SUV) of FDG by muscle tissue per unit volume was calculated, and FDG accumulation was compared between pre- and post-training PET-CT results. Performing part 2 of the 11+ for 4 weeks increased mean SUV in the sartorius, semimembranosus, biceps femoris, abductor hallucis, and flexor hallucis brevis muscles (P < 0.05). In conclusion, routinely performing part 2 of the 11+ for 4 weeks increased glucose uptake related to muscle activity in the hamstrings and hallux muscles. We speculate that there is some possibility of this change of muscle activity contributing to a decrease in sports-related injuries.

  10. Weakly relativistic plasma expansion

    SciTech Connect

    Fermous, Rachid Djebli, Mourad

    2015-04-15

    Plasma expansion is an important physical process that takes place in laser interactions with solid targets. Within a self-similar model for the hydrodynamical multi-fluid equations, we investigated the expansion of both dense and under-dense plasmas. The weakly relativistic electrons are produced by ultra-intense laser pulses, while ions are supposed to be in a non-relativistic regime. Numerical investigations have shown that relativistic effects are important for under-dense plasma and are characterized by a finite ion front velocity. Dense plasma expansion is found to be governed mainly by quantum contributions in the fluid equations that originate from the degenerate pressure in addition to the nonlinear contributions from exchange and correlation potentials. The quantum degeneracy parameter profile provides clues to set the limit between under-dense and dense relativistic plasma expansions at a given density and temperature.

  11. Shoulder weakness in professional baseball pitchers.

    PubMed

    Magnusson, S P; Gleim, G W; Nicholas, J A

    1994-01-01

    The purposes of this study were to: 1) compare shoulder range of motion and strength in professional baseball pitchers (N = 47) compared with age-matched controls (N = 16), and 2) examine the relationship of injury history to strength and range of motion. Based on injury history pitchers were categorized as: 1) none (N = 26), 2) injury requiring conservative intervention (N = 9), or 3) injury requiring surgical intervention (N = 12). Range of motion was measured for internal rotation (IROM) and external rotation (EROM). Eccentric strength was measured by hand-held dynamometer for internal rotation (IR), external rotation (ER), abduction (ABD), and supraspinatus muscle (SUP) strength. Injury history had no effect on strength and range of motion. Dominant EROM was greater in pitchers, P < 0.0001, and controls, P < 0.05, with pitchers having greater EROM motion bilaterally, P < 0.0001. Pitchers were weaker in SUP on the dominant vs nondominant side, P < 0.0001, and on the dominant side for weight adjusted ER, ABD, P < 0.01, and SUP, P < 0.0001, compared with controls. In conclusion, dominance and pitching resulted in soft tissue adaptation. Pitchers displayed weakness in three of four tests by comparison with controls, suggesting that the demands of pitching are insufficient to produce eccentric strength gains and may in fact lead to weakness. Dominant-side SUP weakness in pitchers may reflect subclinical pathology or chronic fatigue.

  12. Muscle biopsy findings in inflammatory myopathies.

    PubMed

    Dalakas, Marinos C

    2002-11-01

    The inflammatory myopathies encompass a heterogeneous group of acquired muscle diseases characterized clinically, by muscle weakness, and histologically, by inflammatory infiltrates within the skeletal muscles. The group of these myopathies comprise three major and discrete subsets: polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM). Each subset retains its characteristic clinical, immunopathologic, and morphologic features regardless of whether it occurs separately or in connection with other systemic diseases. Although the diagnosis of these disorders is based on the combination of clinical examination, electromyographic data, serum muscle enzyme levels, various autoantibodies, and the muscle biopsy findings, the muscle biopsy offers the most definitive diagnostic information in the majority of the cases. This article summarizes the main histologic features that characterize PM, DM, or IBM and emphasizes the main pitfalls associated with interpretation of the biopsies.

  13. Ankle muscle strength influence on muscle activation during dynamic and static ankle training modalities.

    PubMed

    Lucas-Cuevas, Angel Gabriel; Baltich, Jennifer; Enders, Hendrik; Nigg, Sandro; Nigg, Benno

    2016-01-01

    Muscle weakness is considered a risk factor for ankle injury. Balance training and barefoot running have been used in an attempt to strengthen the muscles crossing the ankle. It is expected that training tasks that successfully strengthen the ankle would elicit increased muscular activity. However, it is unknown how an individual's ankle strength will influence the muscle activity used during a given task. Twenty-six participants performed dynamic (shod, barefoot running) and static tasks (squat on ground, squat on ®Bosu Ball) believed to strengthen the muscles surrounding the ankle. Electromyographic signals of the tibialis anterior, peroneus longus, gastrocnemius lateralis (GL) and gastrocnemius medialis (GM) were recorded and analysed using a non-linearly scaled wavelet analysis. Participants were divided into a strong group and a weak group according to their isometric plantar-flexion torque. The weak group required more relative GL and GM muscle activity during each training task compared to the strong group. No difference was observed between shod and barefoot running. There was a significant effect of training task on muscle activation level for the weak group. Differences in ankle strength had a significant impact on muscle activation.

  14. Collagen VI related muscle disorders

    PubMed Central

    Lampe, A; Bushby, K

    2005-01-01

    Mutations in the genes encoding collagen VI (COL6A1, COL6A2, and COL6A3) cause Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD), two conditions which were previously believed to be completely separate entities. BM is a relatively mild dominantly inherited disorder characterised by proximal weakness and distal joint contractures. UCMD was originally described as an autosomal recessive condition causing severe muscle weakness with proximal joint contractures and distal hyperlaxity. Here we review the clinical phenotypes of BM and UCMD and their diagnosis and management, and provide an overview of the current knowledge of the pathogenesis of collagen VI related disorders. PMID:16141002

  15. Measurement of muscle strength in the intensive care unit.

    PubMed

    Bittner, Edward A; Martyn, Jeevendra A; George, Edward; Frontera, Walter R; Eikermann, Matthias

    2009-10-01

    Traditional (indirect) techniques, such as electromyography and nerve conduction velocity measurement, do not reliably predict intensive care unit-acquired muscle weakness and its clinical consequences. Therefore, quantitative assessment of skeletal muscle force is important for diagnosis of intensive care unit-acquired motor dysfunction. There are a number of ways for assessing objectively muscle strength, which can be categorized as techniques that quantify maximum voluntary contraction force and those that assess evoked (stimulated) muscle force. Important factors that limit the repetitive evaluation of maximum voluntary contraction force in intensive care unit patients are learning effects, pain during muscular contraction, and alteration of consciousness.The selection of the appropriate muscle is crucial for making adequate predictions of a patient's outcome. The upper airway dilators are much more susceptible to a decrease in muscle strength than the diaphragm, and impairment of upper airway patency is a key mechanism of extubation failure in intensive care unit patients. Data suggest that the adductor pollicis muscle is an appropriate reference muscle to predict weakness of muscles that are typically affected by intensive care unit-acquired weakness, i.e., upper airway as well as extremity muscles. Stimulated (evoked) force of skeletal muscles, such as the adductor pollicis, can be assessed repetitively, independent of brain function, even in heavily sedated patients during high acuity of their disease. PMID:20046117

  16. Corticospinal excitability modulation to hand muscles during the observation of appropriate versus inappropriate actions.

    PubMed

    Cavallo, Andrea; Sartori, Luisa; Castiello, Umberto

    2011-06-01

    Transcranial magnetic stimulation (TMS) studies have shown that the observation of an action causes subliminal activation within the motor system. However, the issue of whether such an effect is modulated by the match between the observed action and that the observer would have exhibited if acting under similar circumstances remains unclear. We address this issue by recording motor potentials evoked by single-pulse TMS from the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles during the observation of video-clips representing prehensile actions towards small or large objects. In a separate behavioral study, participants were asked to evaluate which type of grasp would be the most appropriate for the tested objects. The TMS data revealed a selective motor facilitation during the observation of movements recruiting the targeted digits. We contend that, in action observation tasks, the human corticospinal system mediating action observation effects codes merely for the visual aspects of the observed action. PMID:24168477

  17. Adductor muscle strains in sport.

    PubMed

    Nicholas, Stephen J; Tyler, Timothy F

    2002-01-01

    An in-season adductor muscle strain may be debilitating for the athlete. Furthermore, an adductor strain that is treated improperly could become chronic and career threatening. Any one of the six muscles of the adductor group could be involved. The degree of injury can range from a minor strain (Grade I), where minimal playing time is lost, to a severe strain (Grade III) in which there is complete loss of muscle function. Ice hockey and soccer players seem particularly susceptible to adductor muscle strains. In professional ice hockey players throughout the world, approximately 10% of all injuries are groin strains. These injuries, which have been linked to hip muscle weakness, previous injuries to that area, preseason practice sessions and level of experience, may be preventable if such risk factors can be addressed before each season. Hip-strengthening exercises were shown to be an effective method of reducing the incidence of adductor strains in one closely followed National Hockey League ice hockey team. Despite the identification of risk factors and strengthening intervention for ice hockey players, adductor strains continue to occur throughout sport. Clinicians feel an active training programme, along with completely restoring the strength of the adductor muscle group, is the key to successful rehabilitation. Surgical intervention is available if nonoperative treatment fails for 6 months or longer. Adductor release and tenotomy was reported to have limited success in athletes. PMID:11929360

  18. Redox control of skeletal muscle atrophy.

    PubMed

    Powers, Scott K; Morton, Aaron B; Ahn, Bumsoo; Smuder, Ashley J

    2016-09-01

    Skeletal muscles comprise the largest organ system in the body and play an essential role in body movement, breathing, and glucose homeostasis. Skeletal muscle is also an important endocrine organ that contributes to the health of numerous body organs. Therefore, maintaining healthy skeletal muscles is important to support overall health of the body. Prolonged periods of muscle inactivity (e.g., bed rest or limb immobilization) or chronic inflammatory diseases (i.e., cancer, kidney failure, etc.) result in skeletal muscle atrophy. An excessive loss of muscle mass is associated with a poor prognosis in several diseases and significant muscle weakness impairs the quality of life. The skeletal muscle atrophy that occurs in response to inflammatory diseases or prolonged inactivity is often associated with both oxidative and nitrosative stress. In this report, we critically review the experimental evidence that provides support for a causative link between oxidants and muscle atrophy. More specifically, this review will debate the sources of oxidant production in skeletal muscle undergoing atrophy as well as provide a detailed discussion on how reactive oxygen species and reactive nitrogen species modulate the signaling pathways that regulate both protein synthesis and protein breakdown.

  19. Differentiation of motor cortical representation of hand muscles by navigated mapping of optimal TMS current directions in healthy subjects

    PubMed Central

    Bashir, Shahid; Perez, Jennifer; Horvath, Jared Cooney; Pascual-Leone, Alvaro

    2013-01-01

    The precision of navigated transcranial magnetic stimulation (TMS) to map the human primary motor cortex may be effected the direction of TMS-induced current in the brain as determined by the orientation of the stimulation coil. In this study, we investigated the effect of current directionality on motor output mapping using navigated brain stimulation (NBS). Our goal was to determine the optimal coil orientation (and, thus, induced brain current) to activate hand musculature representations relative to each subject’s unique neuroanatomical landmarks. We studied motor output maps for the first dorsal interosseous (FDI), abductor pollicis brevis (APB), and abductor digiti minimi (ADM) muscles in 10 normal volunteers. Monopolar current pulses were delivered through a figure-of-eight shaped TMS coil and motor evoked potentials (MEPs) were recorded using electromyography (EMG). At each targeted brain region, we systematically rotated the TMS coil to determine the direction of induced current in the brain for induction of the largest MEPs. These optimal current directions were expressed as an angle relative to each subject’s central sulcus. Consistency of the optimal current direction was assessed by repeating the entire mapping procedure on two different occasions across subjects. We demonstrate that systematic optimization of current direction as guided by MRI based neuronavigation improves the resolution of cortical output motor mapping with TMS. PMID:23912579

  20. Fast and singular muscle responses initiate the startle response of Pantodon buchholzi (Osteoglossomorpha).

    PubMed

    Starosciak, A K; Kalola, R P; Perkins, K P; Riley, J A; Saidel, W M

    2008-01-01

    The startle response of Pantodon buchholzi, the African butterfly fish, is a complete or incomplete ballistic jump resulting from abduction of the pectoral fins. This study analyzed the neuromuscular basis for such a jump by recording in vivo electromyograms (emgs) from the muscles of abduction, the muscularis abductor superficialis (MAS) and the muscularis abductor profundus (MAP). The motor neurons innervating the MAS muscle were localized by retrograde transport of biocytin. The latency between stimulus and the evoked emg in the MAS was less than 5 ms; the latency of the MAP was about 6.5 ms. A single emg was recorded per jump. High speed video demonstrated that onset of a startle movement began within 10 ms of the onset of fin abduction. The emg associated with this movement is short (<2 ms) and followed by a variably-shaped, slower and smaller potential of 10-30 ms duration. The brief period between stimulus and startle response of Pantodon suggests a Mauthner neuron-related response, only with the behavior occurring in the vertical plane. The MAS may act only in a startle response, whereas the MAP might have a role in other behaviors. Elicited jumping habituates after a single trial. Electrophysiological evidence is presented indicating that the innervating motor neurons are suppressed for seconds following a stimulus. The neurons innervating the MAS are located at the medullary-spinal cord junction and possess an average radius of approximately 17.9 mum. These fish have been historically described as 'fresh water' flying fish. As a single emg occurs per startle response, repetitive pectoral activity generating flying cannot be supported. Pantodon 'flight' is ballistic.

  1. Fast and singular muscle responses initiate the startle response of Pantodon buchholzi (Osteoglossomorpha).

    PubMed

    Starosciak, A K; Kalola, R P; Perkins, K P; Riley, J A; Saidel, W M

    2008-01-01

    The startle response of Pantodon buchholzi, the African butterfly fish, is a complete or incomplete ballistic jump resulting from abduction of the pectoral fins. This study analyzed the neuromuscular basis for such a jump by recording in vivo electromyograms (emgs) from the muscles of abduction, the muscularis abductor superficialis (MAS) and the muscularis abductor profundus (MAP). The motor neurons innervating the MAS muscle were localized by retrograde transport of biocytin. The latency between stimulus and the evoked emg in the MAS was less than 5 ms; the latency of the MAP was about 6.5 ms. A single emg was recorded per jump. High speed video demonstrated that onset of a startle movement began within 10 ms of the onset of fin abduction. The emg associated with this movement is short (<2 ms) and followed by a variably-shaped, slower and smaller potential of 10-30 ms duration. The brief period between stimulus and startle response of Pantodon suggests a Mauthner neuron-related response, only with the behavior occurring in the vertical plane. The MAS may act only in a startle response, whereas the MAP might have a role in other behaviors. Elicited jumping habituates after a single trial. Electrophysiological evidence is presented indicating that the innervating motor neurons are suppressed for seconds following a stimulus. The neurons innervating the MAS are located at the medullary-spinal cord junction and possess an average radius of approximately 17.9 mum. These fish have been historically described as 'fresh water' flying fish. As a single emg occurs per startle response, repetitive pectoral activity generating flying cannot be supported. Pantodon 'flight' is ballistic. PMID:18032886

  2. Skeletal muscle involvement in cardiomyopathies.

    PubMed

    Limongelli, Giuseppe; D'Alessandro, Raffaella; Maddaloni, Valeria; Rea, Alessandra; Sarkozy, Anna; McKenna, William J

    2013-12-01

    The link between heart and skeletal muscle disorders is based on similar molecular, anatomical and clinical features, which are shared by the 'primary' cardiomyopathies and 'primary' neuromuscular disorders. There are, however, some peculiarities that are typical of cardiac and skeletal muscle disorders. Skeletal muscle weakness presenting at any age may indicate a primary neuromuscular disorder (associated with creatine kinase elevation as in dystrophinopathies), a mitochondrial disease (particularly if encephalopathy, ocular myopathy, retinitis, neurosensorineural deafness, lactic acidosis are present), a storage disorder (progressive exercise intolerance, cognitive impairment and retinitis pigmentosa, as in Danon disease), or metabolic disorders (hypoglycaemia, metabolic acidosis, hyperammonaemia or other specific biochemical abnormalities). In such patients, skeletal muscle weakness usually precedes the cardiomyopathy and dominates the clinical picture. Nevertheless, skeletal involvement may be subtle, and the first clinical manifestation of a neuromuscular disorder may be the occurrence of heart failure, conduction disorders or ventricular arrhythmias due to cardiomyopathy. ECG and echocardiogram, and eventually, a more detailed cardiovascular evaluation may be required to identify early cardiac involvement. Paediatric and adult cardiologists should be proactive in screening for neuromuscular and related disorders to enable diagnosis in probands and evaluation of families with a focus on the identification of those at risk of cardiac arrhythmia and emboli who may require specific prophylactic treatments, for example, pacemaker, implantable cardioverter-defibrillator and anticoagulation. PMID:24149064

  3. A comparison of respiratory and peripheral muscle strength, functional exercise capacity, activities of daily living and physical fitness in patients with cystic fibrosis and healthy subjects.

    PubMed

    Arikan, Hulya; Yatar, İlker; Calik-Kutukcu, Ebru; Aribas, Zeynep; Saglam, Melda; Vardar-Yagli, Naciye; Savci, Sema; Inal-Ince, Deniz; Ozcelik, Ugur; Kiper, Nural

    2015-01-01

    There are limited reports that compare muscle strength, functional exercise capacity, activities of daily living (ADL) and parameters of physical fitness of cystic fibrosis (CF) patients with healthy peers in the literature. The purpose of this study was to assess and compare respiratory and peripheral muscle strength, functional exercise capacity, ADL and physical fitness in patients with CF and healthy subjects. Nineteen patients with CF (mean forced expiratory volume in one second-FEV1: 86.56±18.36%) and 20 healthy subjects were included in this study. Respiratory (maximal inspiratory pressure-MIP and maximal expiratory pressure-MEP) and peripheral muscle strength (quadriceps, shoulder abductors and hand grip strength) were evaluated. Functional exercise capacity was determined with 6min walk test (6MWT). ADL was assessed with Glittre ADL test and physical fitness was assessed with Munich fitness test (MFT). There were not any statistically significant difference in MIP, %MIP, MEP and %MEP values between two groups (p>0.05). %Peripheral muscle strength (% quadriceps and shoulder abductors strength), 6MWT distance and %6MWT distance were significantly lower in patients with CF than those of healthy subjects (p<0.05). Glittre ADL-test time was significantly longer in patients with CF than healthy subjects (p<0.05). According to Munich fitness test, the number of bouncing a ball, hanging score, distance of standing vertical jumping and standing vertical jumping score were significantly lower in patients with CF than those of healthy subjects (p<0.05). Peripheral muscle strength, functional exercise capacity, ADL performance and speed, coordination, endurance and power components of physical fitness are adversely affected in mild-severe patients with CF compared to healthy peers. Evaluations must be done in comprehensive manner in patients with CF with all stages. PMID:26241869

  4. A comparison of respiratory and peripheral muscle strength, functional exercise capacity, activities of daily living and physical fitness in patients with cystic fibrosis and healthy subjects.

    PubMed

    Arikan, Hulya; Yatar, İlker; Calik-Kutukcu, Ebru; Aribas, Zeynep; Saglam, Melda; Vardar-Yagli, Naciye; Savci, Sema; Inal-Ince, Deniz; Ozcelik, Ugur; Kiper, Nural

    2015-01-01

    There are limited reports that compare muscle strength, functional exercise capacity, activities of daily living (ADL) and parameters of physical fitness of cystic fibrosis (CF) patients with healthy peers in the literature. The purpose of this study was to assess and compare respiratory and peripheral muscle strength, functional exercise capacity, ADL and physical fitness in patients with CF and healthy subjects. Nineteen patients with CF (mean forced expiratory volume in one second-FEV1: 86.56±18.36%) and 20 healthy subjects were included in this study. Respiratory (maximal inspiratory pressure-MIP and maximal expiratory pressure-MEP) and peripheral muscle strength (quadriceps, shoulder abductors and hand grip strength) were evaluated. Functional exercise capacity was determined with 6min walk test (6MWT). ADL was assessed with Glittre ADL test and physical fitness was assessed with Munich fitness test (MFT). There were not any statistically significant difference in MIP, %MIP, MEP and %MEP values between two groups (p>0.05). %Peripheral muscle strength (% quadriceps and shoulder abductors strength), 6MWT distance and %6MWT distance were significantly lower in patients with CF than those of healthy subjects (p<0.05). Glittre ADL-test time was significantly longer in patients with CF than healthy subjects (p<0.05). According to Munich fitness test, the number of bouncing a ball, hanging score, distance of standing vertical jumping and standing vertical jumping score were significantly lower in patients with CF than those of healthy subjects (p<0.05). Peripheral muscle strength, functional exercise capacity, ADL performance and speed, coordination, endurance and power components of physical fitness are adversely affected in mild-severe patients with CF compared to healthy peers. Evaluations must be done in comprehensive manner in patients with CF with all stages.

  5. Relation between isometric muscle force and surface EMG in intrinsic hand muscles as function of the arm geometry.

    PubMed

    Del Santo, Francesco; Gelli, Francesca; Ginanneschi, Federica; Popa, Traian; Rossi, Alessandro

    2007-08-13

    Evidence exists that shoulder joint geometry influences recruitment efficiency and force-generating capacity of hand muscles [Ginanneschi, F., Del Santo, F., Dominici, F., Gelli, F., Mazzocchio, R., Rossi, A., 2005. Changes in corticomotor excitability of hand muscles in relation to static shoulder positions. Exp. Brain Res. 161 (3), 374-382; Dominici, F., Popa, T., Ginanneschi, F., Mazzocchio, R., Rossi, A., 2005. Cortico-motoneural output to intrinsic hand muscles is differentially influenced by static changes in shoulder positions. Exp. Brain Res. 164 (4), 500-504]. The present study was designed to examine the impact of changing shoulder joint position on the relation between surface EMG amplitude and isometric force production of the abductor digiti minimi muscle (ADM). EMG-force relation of ADM was examined in two shoulder positions: 30 degrees adduction (ANT) and 30 degrees abduction (POST) on the horizontal plane, i.e. under higher and lower force-generating capacity, respectively. The relation was studied over the full range isometric force (10-100% of maximum force in 10% increments, 3 s duration) by analysing root mean square (RMS), median frequency (Mf) of the power spectrum and non-linear recurrence quantification analysis (percentage of determinism: %DET) of the surface EMG signals. We found that in POST, the slope of the RMS-force relation was significantly higher than in ANT, while its general shape (strictly linear) was preserved. Averaged Mf of the EMG power spectrum was significantly higher in POST that in ANT, while no difference in %DET was observed between the two shoulder positions. The higher slope of the EMG-force relation in POST than in ANT is interpreted in terms of increased gain of the excitatory drive-firing rate relation. It is concluded that discharge from sensory receptors signalling shoulder position may act to regulate the gain of the excitatory drive-firing rate relation of motoneurones in order to compensate for reduced

  6. Muscle strain (image)

    MedlinePlus

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  7. The effects of smartphone use on upper extremity muscle activity and pain threshold

    PubMed Central

    Lee, Minkyung; Hong, Yunkyung; Lee, Seunghoon; Won, Jinyoung; Yang, Jinjun; Park, Sookyoung; Chang, Kyu-Tae; Hong, Yonggeun

    2015-01-01

    [Purpose] The purpose of this study was to determine whether muscle activity and pressure-induced pain in the upper extremities are affected by smartphone use, and to compare the effects of phone handling with one hand and with both hands. [Subjects] The study subjects were asymptomatic women 20–22 years of age. [Methods] The subjects sat in a chair with their feet on the floor and the elbow flexed, holding a smartphone positioned on the thigh. Subsequently, the subjects typed the Korean anthem for 3 min, one-handed or with both hands. Each subject repeated the task three times, with a 5-min rest period between tasks to minimize fatigue. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor pollicis longus (EPL), and abductor pollicis (AP) during phone operation. We also used a dolorimeter to measure the pressure-induced pain threshold in the UT. [Results] We observed higher muscle activity in the UT, AP, and EPL in one-handed smartphone use than in its two-handed use. The pressure-induced pain threshold of the UT was lower after use of the smartphone, especially after one-handed use. [Conclusion] Our results show that smartphone operation with one hand caused greater UT pain and induced increased upper extremity muscle activity. PMID:26180311

  8. Regenerative function of immune system: Modulation of muscle stem cells.

    PubMed

    Saini, Jasdeep; McPhee, Jamie S; Al-Dabbagh, Sarah; Stewart, Claire E; Al-Shanti, Nasser

    2016-05-01

    Ageing is characterised by progressive deterioration of physiological systems and the loss of skeletal muscle mass is one of the most recognisable, leading to muscle weakness and mobility impairments. This review highlights interactions between the immune system and skeletal muscle stem cells (widely termed satellite cells or myoblasts) to influence satellite cell behaviour during muscle regeneration after injury, and outlines deficits associated with ageing. Resident neutrophils and macrophages in skeletal muscle become activated when muscle fibres are damaged via stimuli (e.g. contusions, strains, avulsions, hyperextensions, ruptures) and release high concentrations of cytokines, chemokines and growth factors into the microenvironment. These localised responses serve to attract additional immune cells which can reach in excess of 1×10(5) immune cell/mm(3) of skeletal muscle in order to orchestrate the repair process. T-cells have a delayed response, reaching peak activation roughly 4 days after the initial damage. The cytokines and growth factors released by activated T-cells play a key role in muscle satellite cell proliferation and migration, although the precise mechanisms of these interactions remain unclear. T-cells in older people display limited ability to activate satellite cell proliferation and migration which is likely to contribute to insufficient muscle repair and, consequently, muscle wasting and weakness. If the factors released by T-cells to activate satellite cells can be identified, it may be possible to develop therapeutic agents to enhance muscle regeneration and reduce the impact of muscle wasting during ageing and disease. PMID:27039885

  9. Regenerative function of immune system: Modulation of muscle stem cells.

    PubMed

    Saini, Jasdeep; McPhee, Jamie S; Al-Dabbagh, Sarah; Stewart, Claire E; Al-Shanti, Nasser

    2016-05-01

    Ageing is characterised by progressive deterioration of physiological systems and the loss of skeletal muscle mass is one of the most recognisable, leading to muscle weakness and mobility impairments. This review highlights interactions between the immune system and skeletal muscle stem cells (widely termed satellite cells or myoblasts) to influence satellite cell behaviour during muscle regeneration after injury, and outlines deficits associated with ageing. Resident neutrophils and macrophages in skeletal muscle become activated when muscle fibres are damaged via stimuli (e.g. contusions, strains, avulsions, hyperextensions, ruptures) and release high concentrations of cytokines, chemokines and growth factors into the microenvironment. These localised responses serve to attract additional immune cells which can reach in excess of 1×10(5) immune cell/mm(3) of skeletal muscle in order to orchestrate the repair process. T-cells have a delayed response, reaching peak activation roughly 4 days after the initial damage. The cytokines and growth factors released by activated T-cells play a key role in muscle satellite cell proliferation and migration, although the precise mechanisms of these interactions remain unclear. T-cells in older people display limited ability to activate satellite cell proliferation and migration which is likely to contribute to insufficient muscle repair and, consequently, muscle wasting and weakness. If the factors released by T-cells to activate satellite cells can be identified, it may be possible to develop therapeutic agents to enhance muscle regeneration and reduce the impact of muscle wasting during ageing and disease.

  10. Electrically controllable artificial PAN muscles

    NASA Astrophysics Data System (ADS)

    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

  11. Capillary muscle

    PubMed Central

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-01-01

    The contraction of a muscle generates a force that decreases when increasing the contraction velocity. This “hyperbolic” force–velocity relationship has been known since the seminal work of A. V. Hill in 1938 [Hill AV (1938) Proc R Soc Lond B Biol Sci 126(843):136–195]. Hill’s heuristic equation is still used, and the sliding-filament theory for the sarcomere [Huxley H, Hanson J (1954) Nature 173(4412):973–976; Huxley AF, Niedergerke R (1954) Nature 173(4412):971–973] suggested how its different parameters can be related to the molecular origin of the force generator [Huxley AF (1957) Prog Biophys Biophys Chem 7:255–318; Deshcherevskiĭ VI (1968) Biofizika 13(5):928–935]. Here, we develop a capillary analog of the sarcomere obeying Hill’s equation and discuss its analogy with muscles. PMID:25944938

  12. RYR1 mutations cause ophthalmoplegia, facial weakness, and malignant hyperthermia

    PubMed Central

    Shaaban, Sherin; Ramos-Platt, Leigh; Gilles, Floyd H.; Chan, Wai-Man; Andrews, Caroline; De Girolami, Umberto; Demer, Joseph; Engle, Elizabeth C

    2013-01-01

    Objective To determine the genetic cause of congenital ptosis, ophthalmoplegia, facial paralysis and mild hypotonia segregating in two pedigrees diagnosed with atypical Moebius syndrome or congenital fibrosis of the extraocular muscles (CFEOM). Methods Homozygosity mapping and whole-exome sequencing were conducted to identify causative mutations in affected family members. Histories, physical examinations, and clinical data were reviewed. Results Missense mutations resulting in two homozygous RYR1 amino acid substitutions (E989G and R3772W) and two compound heterozygous RYR1 substitutions (H283R and R3772W) were identified in a consanguineous and a non-consanguineous pedigree, respectively. Orbital magnetic resonance imaging (MRI) revealed marked hypoplasia of extraocular muscles and intraorbital cranial nerves. Skeletal muscle biopsies revealed non-specific myopathic changes. Clinically, the patients’ ophthalmoplegia and facial weakness were far more significant than their hypotonia and limb weakness, and were accompanied by an unrecognized susceptibility to malignant hyperthermia. Conclusions Affected children presenting with severe congenital ophthalmoplegia and facial weakness in the setting of only mild skeletal myopathy harbored recessive mutations in RYR1, encoding the ryanodine receptor 1, and were susceptible to malignant hyperthermia. While ophthalmoplegia occurs rarely in RYR1-related myopathies, these children were atypical because they lacked significant weakness, respiratory insufficiency, or scoliosis. Clinical relevance RYR1-associated myopathies should be included in the differential diagnosis of congenital ophthalmoplegia and facial weakness, even without clinical skeletal myopathy. These patients should also be considered susceptible to malignant hyperthermia, a life-threatening anesthetic complication avoidable if anticipated pre-surgically. PMID:24091937

  13. Hip and ankle range of motion and hip muscle strength in young female ballet dancersand controls

    PubMed Central

    Bennell, K.; Khan, K. M.; Matthews, B.; De Gruyter, M.; Cook, E.; Holzer, K.; Wark, J. D.

    1999-01-01

    OBJECTIVES: To compare the hip and ankle range of motion and hip muscle strength in 8-11 year old novice female ballet dancers and controls. METHODS: Subjects were 77 dancers and 49 controls (mean (SD) age 9.6 (0.8) and 9.6 (0.7) years respectively). Supine right active hip external rotation (ER) and internal rotation (IR) were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. The measure of ER achieved from below the hip during turnout (non-hip ER) was calculated by subtracting hip ER range from turnout range, and hip ER:IR was derived by dividing ER range by IR range. Range of right weight bearing ankle dorsiflexion was measured in a standing lunge using two methods: the distance from the foot to the wall (in centimetres) and the angle of the shank to the vertical via an inclinometer (in degrees). Right calf muscle range was measured in weight bearing using an inclinometer. A manual muscle tester was used to assess right isometric hip flexor, internal rotator, external rotator, abductor, and adductor strength. RESULTS: Dancers had less ER (p<0.05) and IR (p<0.01) range than controls but greater ER:IR (p<0.01). Although there was no difference in turnout between groups, the dancers had greater non-hip ER. Dancers had greater range of ankle dorsiflexion than controls, measured in both centimetres (p<0.01) and degrees (p<0.05), but similar calf muscle range. After controlling for body weight, controls had stronger hip muscles than dancers except for hip abductor strength which was similar. Regression analyses disclosed a moderate relation between turnout and hip ER (r = 0.40). There were no significant correlations between range of motion and training years and weekly training hours. CONCLUSIONS: Longitudinal follow up will assist in determining whether or not hip and ankle range in young dancers is genetically fixed and unable to be improved with further balletic training. 


 PMID:10522638

  14. Oculopharyngeal muscular dystrophy as a paradigm for muscle aging.

    PubMed

    Raz, Yotam; Raz, Vered

    2014-01-01

    Symptoms in late-onset neuromuscular disorders initiate only from midlife onward and progress with age. These disorders are primarily determined by identified hereditable mutations, but their late-onset symptom manifestation is not fully understood. Here, we review recent research developments on the late-onset autosomal dominant oculopharyngeal muscular dystrophy (OPMD). OPMD is caused by an expansion mutation in the gene encoding for poly-adenylate RNA binding protein1 (PABPN1). The molecular pathogenesis for the disease is still poorly understood. Despite a ubiquitous expression of PABPN1, symptoms in OPMD are limited to skeletal muscles. We discuss recent studies showing that PABPN1 levels in skeletal muscles are lower compared with other tissues, and specifically in skeletal muscles, PABPN1 expression declines from midlife onward. In OPMD, aggregation of expanded PABPN1 causes an additional decline in the level of the functional protein, which is associated with severe muscle weakness in OPMD. Reduced PABNPN1 expression in muscle cell culture causes myogenic defects, suggesting that PABPN1 loss-of-function causes muscle weakness in OPMD and in the elderly. Molecular signatures of OPMD muscles are similar to those of normal muscle aging, although expression trends progress faster in OPMD. We discuss a working hypothesis that aging-associated factors trigger late-onset symptoms in OPMD, and contribute to accelerated muscle weakness in OPMD. We focus on the pharyngeal and eyelid muscles, which are often affected in OPMD patients. We suggest that muscle weakness in OPMD is a paradigm for muscle aging.

  15. Experimental investigations of weak definite and weak indefinite noun phrases

    PubMed Central

    Klein, Natalie M.; Gegg-Harrison, Whitney M.; Carlson, Greg N.; Tanenhaus, Michael K.

    2013-01-01

    Definite noun phrases typically refer to entities that are uniquely identifiable in the speaker and addressee’s common ground. Some definite noun phrases (e.g. the hospital in Mary had to go the hospital and John did too) seem to violate this uniqueness constraint. We report six experiments that were motivated by the hypothesis that these “weak definite” interpretations arise in “incorporated” constructions. Experiments 1-3 compared nouns that seem to allow for a weak definite interpretation (e.g. hospital, bank, bus, radio) with those that do not (e.g. farm, concert, car, book). Experiments 1 and 2 used an instruction-following task and picture-judgment task, respectively, to demonstrate that a weak definite need not uniquely refer. In Experiment 3 participants imagined scenarios described by sentences such as The Federal Express driver had to go to the hospital/farm. The imagined scenarios following weak definite noun phrases were more likely to include conventional activities associated with the object, whereas following regular nouns, participants were more likely to imagine scenarios that included typical activities associated with the subject; similar effects were observed with weak indefinites. Experiment 4 found that object-related activities were reduced when the same subject and object were used with a verb that does not license weak definite interpretations. In Experiment 5, a science fiction story introduced an artificial lexicon for novel concepts. Novel nouns that shared conceptual properties with English weak definite nouns were more likely to allow weak reference in a judgment task. Experiment 6 demonstrated that familiarity for definite articles and anti- familiarity for indefinite articles applies to the activity associated with the noun, consistent with predictions made by the incorporation analysis. PMID:23685208

  16. Inspiratory muscle training in the patient with neuromuscular disease.

    PubMed

    McCool, F D; Tzelepis, G E

    1995-11-01

    Pulmonary complications due to respiratory muscle dysfunction are commonly a source of morbidity and mortality in patients with neuromuscular diseases. This review discusses the adverse effects of respiratory muscle weakness on pulmonary mechanics and examines the role that inspiratory muscle training may play in reversing pulmonary dysfunction in these individuals. In asymptomatic persons, it is well established that the inspiratory muscles can be trained to increase both force and endurance. In patients with neuromuscular diseases, the effects of training protocols on force and endurance are more controversial. This article reviews seven studies that have evaluated respiratory muscle training in a total of 75 patients with varied neuromuscular disorders. Training regimens included breathing through inspiratory resistive loads and isocapnic hyperpnea. Despite methodologic differences among studies, investigators have generally shown that the inspiratory muscles are similar to other skeletal muscle groups in that they can be trained for both force and endurance in these patients. The training-related improvements in inspiratory muscle performance are more pronounced in patients who are less severely affected by their disease. In those patients who have disease to the extent that they are already retaining carbon dioxide, there is little change in force or endurance with training. In these individuals, the inspiratory muscles may already be working at a level sufficiently severe to provide a training stimulus with each breath. No adverse effects of inspiratory muscle training were reported. Inspiratory muscle training can improve force and endurance in patients with neuromuscular weakness.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7480122

  17. Resisting Weakness of the Will

    PubMed Central

    Levy, Neil

    2012-01-01

    I develop an account of weakness of the will that is driven by experimental evidence from cognitive and social psychology. I will argue that this account demonstrates that there is no such thing as weakness of the will: no psychological kind corresponds to it. Instead, weakness of the will ought to be understood as depletion of System II resources. Neither the explanatory purposes of psychology nor our practical purposes as agents are well-served by retaining the concept. I therefore suggest that we ought to jettison it, in favour of the vocabulary and concepts of cognitive psychology. PMID:22984298

  18. Weak-shock reflection factors

    SciTech Connect

    Reichenbach, H.; Kuhl, A.L.

    1993-09-07

    The purpose of this paper is to compare reflection factors for weak shocks from various surfaces, and to focus attention on some unsolved questions. Three different cases are considered: square-wave planar shock reflection from wedges; square-wave planar shock reflection from cylinders; and spherical blast wave reflection from a planar surface. We restrict ourselves to weak shocks. Shocks with a Mach number of M{sub O} < 1.56 in air or with an overpressure of {Delta}{sub PI} < 25 psi (1.66 bar) under normal ambient conditions are called weak.

  19. Respiratory dysfunction in ventilated patients: can inspiratory muscle training help?

    PubMed

    Bissett, B; Leditschke, I A; Paratz, J D; Boots, R J

    2012-03-01

    Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. Moreover, psychological influences, including anxiety, may contribute to difficulty in weaning. There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.

  20. Weak interactions and presupernova evolution

    SciTech Connect

    Aufderheide, M.B. State Univ. of New York . Dept. of Physics)

    1991-02-19

    The role of weak interactions, particularly electron capture and {beta}{sup {minus}} decay, in presupernova evolution is discussed. The present uncertainty in these rates is examined and the possibility of improving the situation is addressed. 12 refs., 4 figs.

  1. Abdominal muscle and quadriceps strength in chronic obstructive pulmonary disease

    PubMed Central

    Man, W; Hopkinson, N; Harraf, F; Nikoletou, D; Polkey, M; Moxham, J

    2005-01-01

    Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and fibre type distribution to the quadriceps, although they remain active in COPD. Cough gastric pressure is a recently described technique that assesses abdominal muscle (and hence expiratory muscle) strength more accurately than traditional techniques. A study was undertaken to test the hypothesis that more severe weakness exists in the quadriceps than in the abdominal muscles of patients with COPD compared with healthy elderly controls. Methods: Maximum cough gastric pressure and quadriceps isometric strength were measured in 43 patients with stable COPD and 25 healthy elderly volunteers matched for anthropometric variables. Results: Despite a significant reduction in mean quadriceps strength (29.9 kg v 41.2 kg; 95% CI –17.9 to –4.6; p = 0.001), cough gastric pressure was preserved in patients with COPD (227.3 cm H2O v 204.8 cm H2O; 95% CI –5.4 to 50.6; p = 0.11). Conclusions: Abdominal muscle strength is preserved in stable COPD outpatients in the presence of quadriceps weakness. This suggests that anatomical location and fibre type cannot explain quadriceps weakness in COPD. By inference, we conclude that disuse and consequent deconditioning are important factors in the development of quadriceps muscle weakness in COPD patients, or that activity protects the abdominal muscles from possible systemic myopathic processes. PMID:15923239

  2. Precision Metrology Using Weak Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Lijian; Datta, Animesh; Walmsley, Ian A.

    2015-05-01

    Weak values and measurements have been proposed as a means to achieve dramatic enhancements in metrology based on the greatly increased range of possible measurement outcomes. Unfortunately, the very large values of measurement outcomes occur with highly suppressed probabilities. This raises three vital questions in weak-measurement-based metrology. Namely, (Q1) Does postselection enhance the measurement precision? (Q2) Does weak measurement offer better precision than strong measurement? (Q3) Is it possible to beat the standard quantum limit or to achieve the Heisenberg limit with weak measurement using only classical resources? We analyze these questions for two prototypical, and generic, measurement protocols and show that while the answers to the first two questions are negative for both protocols, the answer to the last is affirmative for measurements with phase-space interactions, and negative for configuration space interactions. Our results, particularly the ability of weak measurements to perform at par with strong measurements in some cases, are instructive for the design of weak-measurement-based protocols for quantum metrology.

  3. Prevalence of reduced muscle strength in older U.S. adults: United States, 2011-2012.

    PubMed

    Looker, Anne C; Wang, Chia-Yih

    2015-01-01

    Five percent of adults aged 60 and over had weak muscle strength and 13% had intermediate muscle strength, as defined by the new FNIH criteria. Weak muscle strength is clinically relevant because it is associated with slow gait speed, an important mobility impairment. It is also linked to an increased risk of death. The prevalence of reduced muscle strength increased with age and was higher in non-Hispanic Asian and Hispanic persons than in non-Hispanic white or non-Hispanic black persons. Decreasing muscle strength was linked with increased difficulty in rising from an armless chair, which is another important type of mobility impairment. PMID:25633238

  4. Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

    SciTech Connect

    Roberts, B.M.; Frye, G.S.; Ahn, B.; Ferreira, L.F.; Judge, A.R.

    2013-06-07

    Highlights: •C-26 cancer cachexia causes a significant decrease in limb muscle absolute force. •C-26 cancer cachexia causes a significant decrease in limb muscle specific force. •C-26 cancer cachexia decreases fatigue resistance in the soleus muscle. •C-26 cancer cachexia prolongs time to peak twitch tension in limb muscle. •C-26 cancer cachexia prolongs one half twitch relaxation time in limb muscle. -- Abstract: Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative

  5. Connexins in skeletal muscle development and disease.

    PubMed

    Merrifield, Peter A; Laird, Dale W

    2016-02-01

    Gap junctions consist of clusters of intercellular channels composed of connexins that connect adjacent cells and allow the exchange of small molecules. While the 21 member multi-gene family of connexins are ubiquitously found in humans, only Cx39, Cx40, Cx43 and Cx45 have been documented in developing myoblasts and injured adult skeletal muscle while healthy adult skeletal muscle is devoid of connexins. The use of gap junctional blockers and cultured myoblast cell lines have suggested that these connexins play a critical role in myotube formation and muscle regeneration. More recent genetically-modified mouse models where Cx43 function is greatly compromized or ablated have further supported a role for Cx43 in regulating skeletal muscle development. In the last decade, we have become aware of a cohort of patients that have a development disorder known as oculodentodigital dysplasia (ODDD). These patients harbor either gain or loss of Cx43 function gene mutations that result in many organ anomalies raising questions as to whether they suffer from defects in skeletal muscle formation or regeneration upon injury. Interesting, some ODDD patients report muscle weakness and loss of limb control but it is not clear if this is neurogenic or myogenic in origin. This review will focus on the role connexins play in muscle development and repair and discuss the impact of Cx43 mutants on muscle function. PMID:26688333

  6. Supersonic shear imaging provides a reliable measurement of resting muscle shear elastic modulus.

    PubMed

    Lacourpaille, Lilian; Hug, François; Bouillard, Killian; Hogrel, Jean-Yves; Nordez, Antoine

    2012-03-01

    The aim of the present study was to assess the reliability of shear elastic modulus measurements performed using supersonic shear imaging (SSI) in nine resting muscles (i.e. gastrocnemius medialis, tibialis anterior, vastus lateralis, rectus femoris, triceps brachii, biceps brachii, brachioradialis, adductor pollicis obliquus and abductor digiti minimi) of different architectures and typologies. Thirty healthy subjects were randomly assigned to the intra-session reliability (n = 20), inter-day reliability (n = 21) and the inter-observer reliability (n = 16) experiments. Muscle shear elastic modulus ranged from 2.99 (gastrocnemius medialis) to 4.50 kPa (adductor digiti minimi and tibialis anterior). On the whole, very good reliability was observed, with a coefficient of variation (CV) ranging from 4.6% to 8%, except for the inter-operator reliability of adductor pollicis obliquus (CV = 11.5%). The intraclass correlation coefficients were good (0.871 ± 0.045 for the intra-session reliability, 0.815 ± 0.065 for the inter-day reliability and 0.709 ± 0.141 for the inter-observer reliability). Both the reliability and the ease of use of SSI make it a potentially interesting technique that would be of benefit to fundamental, applied and clinical research projects that need an accurate assessment of muscle mechanical properties.

  7. Collagen VI deficiency reduces muscle pathology, but does not improve muscle function, in the γ-sarcoglycan-null mouse.

    PubMed

    de Greef, Jessica C; Hamlyn, Rebecca; Jensen, Braden S; O'Campo Landa, Raul; Levy, Jennifer R; Kobuke, Kazuhiro; Campbell, Kevin P

    2016-04-01

    Muscular dystrophy is characterized by progressive skeletal muscle weakness and dystrophic muscle exhibits degeneration and regeneration of muscle cells, inflammation and fibrosis. Skeletal muscle fibrosis is an excessive deposition of components of the extracellular matrix including an accumulation of Collagen VI. We hypothesized that a reduction of Collagen VI in a muscular dystrophy model that presents with fibrosis would result in reduced muscle pathology and improved muscle function. To test this hypothesis, we crossed γ-sarcoglycan-null mice, a model of limb-girdle muscular dystrophy type 2C, with a Col6a2-deficient mouse model. We found that the resulting γ-sarcoglycan-null/Col6a2Δex5 mice indeed exhibit reduced muscle pathology compared with γ-sarcoglycan-null mice. Specifically, fewer muscle fibers are degenerating, fiber size varies less, Evans blue dye uptake is reduced and serum creatine kinase levels are lower. Surprisingly, in spite of this reduction in muscle pathology, muscle function is not significantly improved. In fact, grip strength and maximum isometric tetanic force are even lower in γ-sarcoglycan-null/Col6a2Δex5 mice than in γ-sarcoglycan-null mice. In conclusion, our results reveal that Collagen VI-mediated fibrosis contributes to skeletal muscle pathology in γ-sarcoglycan-null mice. Importantly, however, our data also demonstrate that a reduction in skeletal muscle pathology does not necessarily lead to an improvement of skeletal muscle function, and this should be considered in future translational studies.

  8. Weak Energy: Form and Function

    NASA Astrophysics Data System (ADS)

    Parks, Allen D.

    The equation of motion for a time-dependent weak value of a quantum mechanical observable contains a complex valued energy factor—the weak energy of evolution. This quantity is defined by the dynamics of the pre-selected and post-selected states which specify the observable's weak value. It is shown that this energy: (i) is manifested as dynamical and geometric phases that govern the evolution of the weak value during the measurement process; (ii) satisfies the Euler-Lagrange equations when expressed in terms of Pancharatnam (P) phase and Fubini-Study (FS) metric distance; (iii) provides for a PFS stationary action principle for quantum state evolution; (iv) time translates correlation amplitudes; (v) generalizes the temporal persistence of state normalization; and (vi) obeys a time-energy uncertainty relation. A similar complex valued quantity—the pointed weak energy of an evolving quantum state—is also defined and several of its properties in PFS coordinates are discussed. It is shown that the imaginary part of the pointed weak energy governs the state's survival probability and its real part is—to within a sign—the Mukunda-Simon geometric phase for arbitrary evolutions or the Aharonov-Anandan (AA) geometric phase for cyclic evolutions. Pointed weak energy gauge transformations and the PFS 1-form are defined and discussed and the relationship between the PFS 1-form and the AA connection 1-form is established. [Editors note: for a video of the talk given by Prof. Parks at the Aharonov-80 conference in 2012 at Chapman University, see http://quantum.chapman.edu/talk-25.

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

    PubMed

    Steinberger, Martin; Föller, Michael; Vogelgesang, Silke; Krautwald, Mirjam; Landsberger, Martin; Winkler, Claudia K; Kasch, Joachim; Füchtbauer, Ernst-Martin; Kuhl, Dietmar; Voelkl, Jakob; Lang, Florian; Brinkmeier, Heinrich

    2015-09-01

    Duchenne muscular dystrophy (DMD) is a human genetic disease characterized by fibrosis and severe muscle weakness. Currently, there is no effective treatment available to prevent progressive fibrosis in skeletal muscles. The serum- and glucocorticoid-inducible kinase SGK1 regulates a variety of physiological functions and participates in fibrosis stimulation. Here, we investigated whether SGK1 influences structure, function and/or fibrosis of the muscles from the mdx mouse, an animal model for DMD. As expected, mdx muscles showed the typical pathological features of muscular dystrophy including fiber size variations, central nuclei of muscle fibers, fibrosis in the diaphragm, and force reduction by 30-50 %. Muscles from sgk1 (-/-) mice were histologically overall intact and specific force was only slightly reduced compared to wild-type muscles. Surprisingly, soleus and diaphragm muscles of mdx/sgk1 (-/-) mice displayed forces close to wild-type levels. Most muscle fibers of the double mutants contained central nuclei, but fibrosis was not observed in any of the tested limb and diaphragm muscles. We conclude that the sole lack of SGK1 in mouse muscle does not lead to pronounced changes in muscle structure and function. However, dystrophin-deficient mdx muscle seems to benefit from SGK1 deficiency. SGK1 appears to be an important enzyme in the process of fibrotic remodeling and subsequent weakness of dystrophin-deficient mouse muscle. PMID:25394886

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

    PubMed

    Steinberger, Martin; Föller, Michael; Vogelgesang, Silke; Krautwald, Mirjam; Landsberger, Martin; Winkler, Claudia K; Kasch, Joachim; Füchtbauer, Ernst-Martin; Kuhl, Dietmar; Voelkl, Jakob; Lang, Florian; Brinkmeier, Heinrich

    2015-09-01

    Duchenne muscular dystrophy (DMD) is a human genetic disease characterized by fibrosis and severe muscle weakness. Currently, there is no effective treatment available to prevent progressive fibrosis in skeletal muscles. The serum- and glucocorticoid-inducible kinase SGK1 regulates a variety of physiological functions and participates in fibrosis stimulation. Here, we investigated whether SGK1 influences structure, function and/or fibrosis of the muscles from the mdx mouse, an animal model for DMD. As expected, mdx muscles showed the typical pathological features of muscular dystrophy including fiber size variations, central nuclei of muscle fibers, fibrosis in the diaphragm, and force reduction by 30-50 %. Muscles from sgk1 (-/-) mice were histologically overall intact and specific force was only slightly reduced compared to wild-type muscles. Surprisingly, soleus and diaphragm muscles of mdx/sgk1 (-/-) mice displayed forces close to wild-type levels. Most muscle fibers of the double mutants contained central nuclei, but fibrosis was not observed in any of the tested limb and diaphragm muscles. We conclude that the sole lack of SGK1 in mouse muscle does not lead to pronounced changes in muscle structure and function. However, dystrophin-deficient mdx muscle seems to benefit from SGK1 deficiency. SGK1 appears to be an important enzyme in the process of fibrotic remodeling and subsequent weakness of dystrophin-deficient mouse muscle.

  11. Myosin Binding Protein-C Slow Phosphorylation is Altered in Duchenne Dystrophy and Arthrogryposis Myopathy in Fast-Twitch Skeletal Muscles

    PubMed Central

    Ackermann, Maegen A.; Ward, Christopher W.; Gurnett, Christina; Kontrogianni-Konstantopoulos, Aikaterini

    2015-01-01

    Myosin Binding Protein-C slow (sMyBP-C), encoded by MYBPC1, comprises a family of regulatory proteins of skeletal muscles that are phosphorylated by PKA and PKC. MYBPC1 missense mutations are linked to the development of Distal Arthrogryposis-1 (DA-1). Although structure-function details for this myopathy are evolving, function is undoubtedly driven by sequence variations and post-translational modifications in sMyBP-C. Herein, we examined the phosphorylation profile of sMyBP-C in mouse and human fast-twitch skeletal muscles. We used Flexor Digitorum Brevis (FDB) isolated from young (~2-months old) and old (~14-months old) wild type and mdx mice, and human Abductor Hallucis (AH) and gastrocnemious muscles carrying the DA-1 mutations. Our results indicate both constitutive and differential phosphorylation of sMyBP-C in aged and diseased muscles. We report a 7–35% reduction in the phosphorylation levels of select sites in old wild type and young or old mdx FDB mouse muscles, compared to young wild type tissue. Similarly, we observe a 30–70% decrease in the phosphorylation levels of all PKA and PKC phospho-sites in the DA-1 AH, but not gastrocnemius, muscle. Overall, our studies show that the phosphorylation pattern of sMyBP-C is differentially regulated in response to age and disease, suggesting that phosphorylation plays important roles in these processes. PMID:26287277

  12. Jar-opening challenges. Part 2: estimating the force-generating capacity of thumb muscles in healthy young adults during jar-opening tasks.

    PubMed

    Kuo, L C; Chang, J H; Lin, C F; Hsu, H Y; Ho, K Y; Su, F C

    2009-07-01

    This study discusses the force-generating capacity of thumb muscles during jar-opening tasks using two grip patterns: the power grip and the precision grip. This study develops a three-dimensional biomechanical model of the thumb to predict muscle forces in jar-opening activities based on external forces measured by a custom-designed jar device. Ten healthy subjects participated in the study. Each participant turned a jar lid of 66 mm diameter counterclockwise with maximal effort and preferred speed using both grip patterns. The average normal and tangential forces applied by the thumb to the jar lid show that the normal force is the primary contributive force for opening a jar. This normal force is approximately three times the tangential force. Muscular force-generating capacity measurements show that the major active muscles during a jar-opening activity for both grips include the flexor pollicis longus, flexor pollicis brevis, abductor pollicis brevis, adductor pollicis, and opponens pollicis. The total muscle force ratios for the precision grip and power grip with respect to externally applied forces are 5.6 and 4.7 respectively. These ratios indicate that the power grip pattern produces less muscle force per unit of external applied load. The technique proposed in this study provides a proper apparatus and model for measuring three-dimensional loads and estimating the force-generating capacity of each muscle and tendon of the thumb during jar-opening tasks. PMID:19623911

  13. Muscle strain treatment

    MedlinePlus

    Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...

  14. Eye muscle repair - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000111.htm Eye muscle repair - discharge To use the sharing features on ... enable JavaScript. You or your child had eye muscle repair surgery to correct eye muscle problems that ...

  15. Quantum discord with weak measurements

    SciTech Connect

    Singh, Uttam Pati, Arun Kumar

    2014-04-15

    Weak measurements cause small change to quantum states, thereby opening up the possibility of new ways of manipulating and controlling quantum systems. We ask, can weak measurements reveal more quantum correlation in a composite quantum state? We prove that the weak measurement induced quantum discord, called as the “super quantum discord”, is always larger than the quantum discord captured by the strong measurement. Moreover, we prove the monotonicity of the super quantum discord as a function of the measurement strength and in the limit of strong projective measurement the super quantum discord becomes the normal quantum discord. We find that unlike the normal discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. Our results provide new insights on the nature of quantum correlation and suggest that the notion of quantum correlation is not only observer dependent but also depends on how weakly one perturbs the composite system. We illustrate the key results for pure as well as mixed entangled states. -- Highlights: •Introduced the role of weak measurements in quantifying quantum correlation. •We have introduced the notion of the super quantum discord (SQD). •For pure entangled state, we show that the SQD exceeds the entanglement entropy. •This shows that quantum correlation depends not only on observer but also on measurement strength.

  16. Weak Selection and Protein Evolution

    PubMed Central

    Akashi, Hiroshi; Osada, Naoki; Ohta, Tomoko

    2012-01-01

    The “nearly neutral” theory of molecular evolution proposes that many features of genomes arise from the interaction of three weak evolutionary forces: mutation, genetic drift, and natural selection acting at its limit of efficacy. Such forces generally have little impact on allele frequencies within populations from generation to generation but can have substantial effects on long-term evolution. The evolutionary dynamics of weakly selected mutations are highly sensitive to population size, and near neutrality was initially proposed as an adjustment to the neutral theory to account for general patterns in available protein and DNA variation data. Here, we review the motivation for the nearly neutral theory, discuss the structure of the model and its predictions, and evaluate current empirical support for interactions among weak evolutionary forces in protein evolution. Near neutrality may be a prevalent mode of evolution across a range of functional categories of mutations and taxa. However, multiple evolutionary mechanisms (including adaptive evolution, linked selection, changes in fitness-effect distributions, and weak selection) can often explain the same patterns of genome variation. Strong parameter sensitivity remains a limitation of the nearly neutral model, and we discuss concave fitness functions as a plausible underlying basis for weak selection. PMID:22964835

  17. Relationship between Isometric Strength of Six Lower Limb Muscle Groups and Motor Skills among Nursing Home Residents.

    PubMed

    Buckinx, F; Croisier, J L; Reginster, J Y; Petermans, J; Goffart, E; Bruyère, O

    2015-01-01

    This research aimed to assess the correlation between isometric muscle strength of the lower limb and motor skills. This is a cross sectional study performed among volunteer nursing home residents included in the SENIOR (Sample of Elderly Nursing home Individuals: an Observational Research) cohort. The present analysis focused on isometric muscle strength of 6 lower limb muscle groups (i.e. knee extensors, knee flexors, hip abductors, hip extensors, ankle flexors and ankle extensors), assessed using a validated hand-held dynamometer (i.e. the MicroFET2 device), and motor skills evaluated using the Tinetti test, the Timed Up and Go test, the Short Physical Performance Battery test (SPPB) and the walking speed. The relationship between all these parameters was tested by means of a multiple correlation, adjusted on age, sex and body mass index. 450 nursing home residents (69.8% of women) with a mean age of 83.1±9.4 years were included in this study. Our results showed a significant inverse correlation between lower limb muscle strength and the time required to perform the TUG test or gait speed, except for ankle flexors and ankle extensors. The relationship between the Tinetti test or the SPPB score, and lower limb muscle strength was significant, except for ankle flexors and ankle extensors. In conclusion, a positive association between lower limb muscle strength of the four main muscle groups and motor skills of the elderly nursing residents was found in this research. Therefore, special attention should be given to these muscle groups during rehabilitation programs.

  18. Warping the Weak Gravity Conjecture

    NASA Astrophysics Data System (ADS)

    Kooner, Karta; Parameswaran, Susha; Zavala, Ivonne

    2016-08-01

    The Weak Gravity Conjecture, if valid, rules out simple models of Natural Inflation by restricting their axion decay constant to be sub-Planckian. We revisit stringy attempts to realise Natural Inflation, with a single open string axionic inflaton from a probe D-brane in a warped throat. We show that warped geometries can allow the requisite super-Planckian axion decay constant to be achieved, within the supergravity approximation and consistently with the Weak Gravity Conjecture. Preliminary estimates of the brane backreaction suggest that the probe approximation may be under control. However, there is a tension between large axion decay constant and high string scale, where the requisite high string scale is difficult to achieve in all attempts to realise large field inflation using perturbative string theory. We comment on the Generalized Weak Gravity Conjecture in the light of our results.

  19. State tomography via weak measurements

    PubMed Central

    Wu, Shengjun

    2013-01-01

    Recent work has revealed that the wave function of a pure state can be measured directly and that complementary knowledge of a quantum system can be obtained simultaneously by weak measurements. However, the original scheme applies only to pure states, and it is not efficient because most of the data are discarded by post-selection. Here, we propose tomography schemes for pure states and for mixed states via weak measurements, and our schemes are more efficient because we do not discard any data. Furthermore, we demonstrate that any matrix element of a general state can be directly read from an appropriate weak measurement. The density matrix (with all of its elements) represents all that is directly accessible from a general measurement. PMID:23378924

  20. Cytokine Signaling in Skeletal Muscle Wasting.

    PubMed

    Zhou, Jin; Liu, Bin; Liang, Chun; Li, Yangxin; Song, Yao-Hua

    2016-05-01

    Skeletal muscle wasting occurs in a variety of diseases including diabetes, cancer, Crohn's disease, chronic obstructive pulmonary disease (COPD), disuse, and denervation. Tumor necrosis factor α (TNF-α) is involved in mediating the wasting effect. To date, a causal relationship between TNF-α signaling and muscle wasting has been established in animal models. However, results from clinical trials are conflicting. This is partly due to the fact that other factors such as TNF-like weak inducer of apoptosis (TWEAK) and interleukin 6 (IL-6) are also involved in skeletal muscle wasting. Because muscle wasting is often associated with physical inactivity and reduced food intake, therapeutic interventions will be most effective when multiple approaches are used in conjunction with nutritional support and exercise. PMID:27025788

  1. The skeletal muscle arachidonic acid cascade in health and inflammatory disease.

    PubMed

    Korotkova, Marina; Lundberg, Ingrid E

    2014-05-01

    Muscle atrophy and weakness are often observed in patients with chronic inflammatory diseases, and are the major clinical features of the autoimmune myopathies, polymyositis and dermatomyositis. A general understanding of the pathogenesis of muscle atrophy and the impaired muscle function associated with chronic inflammatory diseases has not been clarified. In this context, arachidonic acid metabolites, such as the prostaglandin and leukotriene subfamilies, are of interest because they contribute to immune and nonimmune processes. Accumulating evidence suggests that prostaglandins and leukotrienes are involved in causing muscular pain and inflammation, and also in myogenesis and the repair of muscles. In this Review, we summarize novel findings that implicate prostaglandins and leukotrienes in the muscle atrophy and weakness that occur in inflammatory diseases of the muscles, with a focus on inflammatory myopathies. We discuss the role of the arachidonic acid cascade in skeletal muscle growth and function, and individual metabolites as potential therapeutic targets for the treatment of inflammatory muscle diseases.

  2. Cosmology and the weak interaction

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1989-01-01

    The weak interaction plays a critical role in modern Big Bang cosmology. Two of its most publicized comological connections are emphasized: big bang nucleosynthesis and dark matter. The first of these is connected to the cosmological prediction of neutrine flavors, N(sub nu) is approximately 3 which in now being confirmed. The second is interrelated to the whole problem of galacty and structure formation in the universe. The role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure is demonstrated.

  3. Weak value amplification considered harmful

    NASA Astrophysics Data System (ADS)

    Ferrie, Christopher; Combes, Joshua

    2014-03-01

    We show using statistically rigorous arguments that the technique of weak value amplification does not perform better than standard statistical techniques for the tasks of parameter estimation and signal detection. We show that using all data and considering the joint distribution of all measurement outcomes yields the optimal estimator. Moreover, we show estimation using the maximum likelihood technique with weak values as small as possible produces better performance for quantum metrology. In doing so, we identify the optimal experimental arrangement to be the one which reveals the maximal eigenvalue of the square of system observables. We also show these conclusions do not change in the presence of technical noise.

  4. Cosmology and the weak interaction

    SciTech Connect

    Schramm, D.N. ):)

    1989-12-01

    The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.

  5. Effects of Nordic walking on pelvis motion and muscle activities around the hip joints of adults with hip osteoarthritis

    PubMed Central

    Homma, Daisuke; Jigami, Hirofumi; Sato, Naritoshi

    2016-01-01

    [Purpose] Increased compensatory pelvic movement is remarkable in limping patients with hip osteoarthritis (OA). However, a method of improving limping has not been established. The purpose of this study was to identify the effects of two types of Nordic walking by analyzing the pelvic movement and muscle activities of adults with hip OA. [Subjects and Methods] Ten patients with OA of the hip performed Japanese-style Nordic walking (JS NW), European-style Nordic walking (ES NW), and Ordinary walking (OW), and the muscle activities around the hip joint and pelvic movements were analyzed. [Results] The pelvic rotation angle was significantly larger in ES NW than in JS NW. In the stance phase, hip abductor muscle activity was significantly decreased in JS NW compared to both OW and ES NW. In the swing phase, rectus abdominis muscle activity was significantly increased in both JS NW and ES NW compared to OW and lumbar erector spinae activity was significantly lower in JS NW than in OW. [Conclusion] JS NW style may reduce the compensatory pelvic rotation in patients with hip OA. JS NW might be better for joint protection and prevention of secondary disorders of the hip in OA patients. PMID:27190455

  6. Effects of Nordic walking on pelvis motion and muscle activities around the hip joints of adults with hip osteoarthritis.

    PubMed

    Homma, Daisuke; Jigami, Hirofumi; Sato, Naritoshi

    2016-04-01

    [Purpose] Increased compensatory pelvic movement is remarkable in limping patients with hip osteoarthritis (OA). However, a method of improving limping has not been established. The purpose of this study was to identify the effects of two types of Nordic walking by analyzing the pelvic movement and muscle activities of adults with hip OA. [Subjects and Methods] Ten patients with OA of the hip performed Japanese-style Nordic walking (JS NW), European-style Nordic walking (ES NW), and Ordinary walking (OW), and the muscle activities around the hip joint and pelvic movements were analyzed. [Results] The pelvic rotation angle was significantly larger in ES NW than in JS NW. In the stance phase, hip abductor muscle activity was significantly decreased in JS NW compared to both OW and ES NW. In the swing phase, rectus abdominis muscle activity was significantly increased in both JS NW and ES NW compared to OW and lumbar erector spinae activity was significantly lower in JS NW than in OW. [Conclusion] JS NW style may reduce the compensatory pelvic rotation in patients with hip OA. JS NW might be better for joint protection and prevention of secondary disorders of the hip in OA patients.

  7. Muscle shape consistency and muscle volume prediction of thigh muscles.

    PubMed

    Mersmann, F; Bohm, S; Schroll, A; Boeth, H; Duda, G; Arampatzis, A

    2015-04-01

    The present study investigated the applicability of a muscle volume prediction method using only the muscle length (L(M)), the maximum anatomical cross-sectional area (ACSA(max)), and a muscle-specific shape factor (p) on the quadriceps vastii. L(M), ACSA(max), muscle volume, and p were obtained from magnetic resonance images of the vastus intermedius (VI), lateralis (VL), and medialis (VM) of female (n = 20) and male (n = 17) volleyball athletes. The average p was used to predict muscle volumes (V(p)) using the equation V(p)  = p × ACSA(max)  × L(M). Although there were significant differences in the muscle dimensions between male and female athletes, p was similar and on average 0.582, 0.658, 0.543 for the VI, VL, and VM, respectively. The position of ACSA(max) showed low variability and was at 57%, 60%, and 81% of the thigh length for VI, VL, and VM. Further, there were no significant differences between measured and predicted muscle volumes with root mean square differences of 5-8%. These results suggest that the muscle shape of the quadriceps vastii is independent of muscle dimensions or sex and that the prediction method could be sensitive enough to detect changes in muscle volume related to degeneration, atrophy, or hypertrophy.

  8. The association between hip muscle cross-sectional area, muscle strength, and bone mineral density.

    PubMed

    Ahedi, Harbeer; Aitken, Dawn; Scott, David; Blizzard, Leigh; Cicuttini, Flavia; Jones, Graeme

    2014-07-01

    Studies examining the association between muscle size, muscle strength, and bone mineral density (BMD) are limited. Thus, this study aimed to describe the association between hip muscles cross-sectional area (CSA), muscle strength, and BMD of the hip and spine. A total of 321 subjects from the Tasmanian Older Adult Cohort study with a right hip MRI scan conducted between 2004 and 2006 were included. Hip muscles were measured on MR images by OsiriX (Geneva) software measuring maximum muscle CSA (cm(2)) of gluteus maximus, obturator externus, gemelli, quadratus femoris, piriformis, pectineus, sartorius, and iliopsoas. Dual-energy X-ray absorptiometry measured total hip, femoral neck, and spine BMD, and lower limb muscle strength was assessed by dynamometer. Muscle CSA of the hip flexors (pectineus, sartorius, and iliopsoas) and the hip rotators, obturator externus, and quadratus femoris were associated with both total hip and femoral neck BMD (all p < 0.05). The associations between CSA of pectineus and sartorius and BMD were stronger in women (p = 0.01-0.001) compared to men (p = 0.12-0.54). Additionally, only gemelli CSA was associated with BMD of the spine (p = 0.002). Gluteus maximus and piriformis showed no relationship with BMD. CSA of most hip muscles (except gluteus maximus and gemelli) were positively associated with leg strength (p = 0.02 to <0.001). Lastly, leg strength was weakly associated with BMD (p = 0.11-0.007). Hip muscle CSA, and to a lesser extent muscle strength, were positively associated with hip BMD. These data suggest that both higher muscle mass and strength may contribute to the maintenance of bone mass and prevention of disease progression in older adults. PMID:24829114

  9. Cosmology with weak lensing surveys.

    PubMed

    Munshi, Dipak; Valageas, Patrick

    2005-12-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bi-spectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy.

  10. Weak localization of seismic waves.

    PubMed

    Larose, E; Margerin, L; Van Tiggelen, B A; Campillo, M

    2004-07-23

    We report the observation of weak localization of seismic waves in a natural environment. It emerges as a doubling of the seismic energy around the source within a spot of the width of a wavelength, which is several tens of meters in our case. The characteristic time for its onset is the scattering mean-free time that quantifies the internal heterogeneity.

  11. Cosmology with weak lensing surveys.

    PubMed

    Munshi, Dipak; Valageas, Patrick

    2005-12-15

    Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening mass. Since the lensing effects arise from deflections of the light rays due to fluctuations of the gravitational potential, they can be directly related to the underlying density field of the large-scale structures. Weak gravitational surveys are complementary to both galaxy surveys and cosmic microwave background observations as they probe unbiased nonlinear matter power spectra at medium redshift. Ongoing CMBR experiments such as WMAP and a future Planck satellite mission will measure the standard cosmological parameters with unprecedented accuracy. The focus of attention will then shift to understanding the nature of dark matter and vacuum energy: several recent studies suggest that lensing is the best method for constraining the dark energy equation of state. During the next 5 year period, ongoing and future weak lensing surveys such as the Joint Dark Energy Mission (JDEM; e.g. SNAP) or the Large-aperture Synoptic Survey Telescope will play a major role in advancing our understanding of the universe in this direction. In this review article, we describe various aspects of probing the matter power spectrum and the bi-spectrum and other related statistics with weak lensing surveys. This can be used to probe the background dynamics of the universe as well as the nature of dark matter and dark energy. PMID:16286284

  12. N-{Delta} weak transition

    SciTech Connect

    Graczyk, Krzysztof M.

    2011-11-23

    A short review of the Rein-Sehgal and isobar models is presented. The attention is focused on the nucleon-{Delta}(1232) weak transition form-factors. The results of the recent re-analyses of the ANL and BNL bubble chamber neutrino-deuteron scattering data are discussed.

  13. Effects of microgravity on rat muscle

    NASA Technical Reports Server (NTRS)

    Riley, D. A.

    1990-01-01

    It is well known that humans exposed to long term spaceflight experience undesirable progressive muscle weakness and increased fatigability. This problem has prompted the implementation of inflight exercise programs because most investigators believe that the major cause of diminished muscle performance is a combination of disuse and decreased workload. Inflight exercise has improved muscle health, but deficits have persisted, indicating that either the regimens utilized were suboptimal or there existed additional debilitating factors which were not remedied by exercise. Clarification of this question requires an improved understanding of the cellular and molecular basis of spaceflight-induced muscle deterioration. To this end, multiple investigations have been performed on the muscles from rats orbited 5 to 22 days in Cosmos biosatellites and Spacelab-3 (2,4,5,8,10 to 14,16,18,19,21 to 23,25,27,28). The eight Cosmos 1887 investigations examined the structural and biochemical changes in skeletal and cardiac muscles of rats exposed to microgravity for 12.5 days and returned to terrestrial gravity 2.3 days before tissues were collected. Even though interpretation of these results was complicated by the combination of inflight and postflight induced alterations, the consensus is that there is marked heterogeneity in both degree and type of responses from the whole muscle level down to the molecular level. Collectively, the muscle investigations of Cosmos 1887 clearly illustrate the wide diversity of muscle tissue responses to spaceflight. Judging from the summary report of this mission, heterogeneity of responses is not unique to muscle tissue. Elucidating the mechanism underlying this heterogeneity holds the key to explaining adaptation of the organism to prolonged spaceflight.

  14. Acute effects of muscle vibration on sensorimotor integration.

    PubMed

    Lapole, Thomas; Tindel, Jérémy

    2015-02-01

    Projections from the somesthetic cortex are believed to be involved in the modulation of motor cortical excitability by muscle vibration. The aim of the present pilot study was to analyse the effects of a vibration intervention on short-latency afferent inhibition (SAI), long-latency afferent inhibition (LAI), and afferent facilitation (AF), three intracortical mechanisms reflecting sensorimotor integration. Abductor pollicis brevis (APB) SAI, AF and LAI were investigated on 10 subjects by conditioning test transcranial magnetic stimulation pulses with median nerve electrical stimulation at inter-stimuli intervals in the range 15-25 ms, 25-60 ms, and 100-200 ms, respectively. Test motor evoked potentials (MEPs) were compared to unconditioned MEPs. Measurements were performed before and just after 15 min of vibration applied to the muscle belly of APB at a frequency of 80 Hz. SAI and LAI responses were significantly reduced compared to unconditioned test MEPs (P=0.039 and P<0.001, respectively). AF MEP amplitude was greater than SAI and LAI one (P=0.009 and P=0.004, respectively), but not different from test MEP (P=0.511). There was no significant main effect of vibration (P=0.905). However, 4 subjects were clearly identified as responders. Their mean vibration-induced increase was 324 ± 195% in APB SAI MEP amplitude, and 158 ± 53% and 319 ± 80% in AF and LAI, respectively. Significant differences in SAI, AF and LAI vibration-induced changes were found for responders when compared to non-responders (P=0.019, P=0.038, and P=0.01, respectively). A single session of APB vibration may increase sensorimotor integration, via decreased inhibition and increased facilitation. However, such results were not observed for all subjects, suggesting that other factors (such as attention to the sensory inputs) may have played a role.

  15. Bone mineral density, muscle strength, and recreational exercise in men

    NASA Technical Reports Server (NTRS)

    Snow-Harter, C.; Whalen, R.; Myburgh, K.; Arnaud, S.; Marcus, R.

    1992-01-01

    Muscle strength has been shown to predict bone mineral density (BMD) in women. We examined this relationship in 50 healthy men who ranged in age from 28 to 51 years (average 38.3 years). BMD of the lumbar spine, proximal femur, whole body, and tibia were measured by dual-energy x-ray absorptiometry (Hologic QDR 1000W). Dynamic strength using one repetition maximum was assessed for the biceps, quadriceps, and back extensors and for the hip abductors, adductors, and flexors. Isometric grip strength was measured by dynamometry. Daily walking mileage was assessed by 9 week stepmeter records and kinematic analysis of video filming. Subjects were designated as exercisers and nonexercisers. Exercisers participated in recreational exercise at least two times each week. The results demonstrated that BMD at all sites correlated with back and biceps strength (p < 0.01 to p = 0.0001). Body weight correlated with tibia and whole-body BMD (p < 0.001); age negatively correlated with Ward's triangle BMD (p < 0.01). In stepwise multiple regressions, back strength was the only independent predictor of spine and femoral neck density (R2 = 0.27). Further, back strength was the most robust predictor of BMD at the trochanter, Ward's triangle, whole body, and tibia, although biceps strength, age, body weight, and leg strength contributed significantly to BMD at these skeletal sites, accounting for 35-52% of the variance in BMD. Exercisers and nonexercisers were similar for walking (3.97 versus 3.94 miles/day), age (37.8 versus 38.5) years, and weight (80.0 versus 77.7 kg). However, BMD and muscle strength were significantly greater in exercises than in nonexercisers.(ABSTRACT TRUNCATED AT 250 WORDS).

  16. Competing weak localization and weak antilocalization in ultrathin topological insulators.

    PubMed

    Lang, Murong; He, Liang; Kou, Xufeng; Upadhyaya, Pramey; Fan, Yabin; Chu, Hao; Jiang, Ying; Bardarson, Jens H; Jiang, Wanjun; Choi, Eun Sang; Wang, Yong; Yeh, Nai-Chang; Moore, Joel; Wang, Kang L

    2013-01-01

    We demonstrate evidence of a surface gap opening in topological insulator (TI) thin films of (Bi(0.57)Sb(0.43))(2)Te(3) below six quintuple layers through transport and scanning tunneling spectroscopy measurements. By effective tuning the Fermi level via gate-voltage control, we unveil a striking competition between weak localization and weak antilocalization at low magnetic fields in nonmagnetic ultrathin films, possibly owing to the change of the net Berry phase. Furthermore, when the Fermi level is swept into the surface gap of ultrathin samples, the overall unitary behaviors are revealed at higher magnetic fields, which are in contrast to the pure WAL signals obtained in thicker films. Our findings show an exotic phenomenon characterizing the gapped TI surface states and point to the future realization of quantum spin Hall effect and dissipationless TI-based applications.

  17. CARDIAC MUSCLE

    PubMed Central

    Sommer, Joachim R.; Johnson, Edward A.

    1968-01-01

    With light and electron microscopy a comparison has been made of the morphology of ventricular (V) and Purkinje (P) fibers of the hearts of guinea pig, rabbit, cat, dog, goat, and sheep. The criteria, previously established for the rabbit heart, that V fibers are distinguished from P fibers by the respective presence and absence of transverse tubules is shown to be true for all animals studied. No evidence was found of a permanent connection between the sarcoplasmic reticulum and the extracellular space. The sarcoplasmic reticulum (SR) of V fibers formed couplings with the sarcolemma of a transverse tubule (interior coupling) and with the peripheral sarcolemma (peripheral coupling), whereas in P fibers the SR formed only peripheral couplings. The forms of the couplings were identical. The significance, with respect to excitation-contraction coupling, of the difference in the form of the couplings in cardiac versus skeletal muscle is discussed together with the electrophysiological implications of the differing geometries of bundles of P fibers from different animals. PMID:5645545

  18. From mental power to muscle power--gaining strength by using the mind.

    PubMed

    Ranganathan, Vinoth K; Siemionow, Vlodek; Liu, Jing Z; Sahgal, Vinod; Yue, Guang H

    2004-01-01

    The purposes of this project were to determine mental training-induced strength gains (without performing physical exercises) in the little finger abductor as well as in the elbow flexor muscles, which are frequently used during daily living, and to quantify cortical signals that mediate maximal voluntary contractions (MVCs) of the two muscle groups. Thirty young, healthy volunteers participated in the study. The first group (N = 8) was trained to perform "mental contractions" of little finger abduction (ABD); the second group (N = 8) performed mental contractions of elbow (ELB) flexion; and the third group (N = 8) was not trained but participated in all measurements and served as a control group. Finally, six volunteers performed training of physical maximal finger abductions. Training lasted for 12 weeks (15 min per day, 5 days per week). At the end of training, we found that the ABD group had increased their finger abduction strength by 35% (P < 0.005) and the ELB group augmented their elbow flexion strength by 13.5% (P < 0.001). The physical training group increased the finger abduction strength by 53% (P < 0.01). The control group showed no significant changes in strength for either finger abduction or elbow flexion tasks. The improvement in muscle strength for trained groups was accompanied by significant increases in electroencephalogram-derived cortical potential, a measure previously shown to be directly related to control of voluntary muscle contractions. We conclude that the mental training employed by this study enhances the cortical output signal, which drives the muscles to a higher activation level and increases strength. PMID:14998709

  19. The Pilates Method increases respiratory muscle strength and performance as well as abdominal muscle thickness.

    PubMed

    Giacomini, Mateus Beltrame; da Silva, Antônio Marcos Vargas; Weber, Laura Menezes; Monteiro, Mariane Borba

    2016-04-01

    The aim of this study was to verify the effects of the Pilates Method (PM) training program on the thickness of the abdominal wall muscles, respiratory muscle strength and performance, and lung function. This uncontrolled clinical trial involved 16 sedentary women who were assessed before and after eight weeks of PM training. The thickness of the transversus abdominis (TrA), internal oblique (IO) and external oblique (EO) muscles was assessed. The respiratory muscle strength was assessed by measuring the maximum inspiratory (MIP) and expiratory (MEP) pressure. The lung function and respiratory muscle performance were assessed by spirometry. An increase was found in MIP (p = 0.001), MEP (p = 0.031), maximum voluntary ventilation (p = 0.020) and the TrA (p < 0.001), IO (p = 0.002) and EO (p < 0.001) thickness after the PM program. No alterations in lung function were found. These findings suggest that the PM program promotes abdominal wall muscle hypertrophy and an increase in respiratory muscle strength and performance, preventing weakness in abdominal muscles and dysfunction in ventilatory mechanics, which could favor the appearance of illnesses. PMID:27210841

  20. The Pilates Method increases respiratory muscle strength and performance as well as abdominal muscle thickness.

    PubMed

    Giacomini, Mateus Beltrame; da Silva, Antônio Marcos Vargas; Weber, Laura Menezes; Monteiro, Mariane Borba

    2016-04-01

    The aim of this study was to verify the effects of the Pilates Method (PM) training program on the thickness of the abdominal wall muscles, respiratory muscle strength and performance, and lung function. This uncontrolled clinical trial involved 16 sedentary women who were assessed before and after eight weeks of PM training. The thickness of the transversus abdominis (TrA), internal oblique (IO) and external oblique (EO) muscles was assessed. The respiratory muscle strength was assessed by measuring the maximum inspiratory (MIP) and expiratory (MEP) pressure. The lung function and respiratory muscle performance were assessed by spirometry. An increase was found in MIP (p = 0.001), MEP (p = 0.031), maximum voluntary ventilation (p = 0.020) and the TrA (p < 0.001), IO (p = 0.002) and EO (p < 0.001) thickness after the PM program. No alterations in lung function were found. These findings suggest that the PM program promotes abdominal wall muscle hypertrophy and an increase in respiratory muscle strength and performance, preventing weakness in abdominal muscles and dysfunction in ventilatory mechanics, which could favor the appearance of illnesses.

  1. Weak values and weak coupling maximizing the output of weak measurements

    SciTech Connect

    Di Lorenzo, Antonio

    2014-06-15

    In a weak measurement, the average output 〈o〉 of a probe that measures an observable A{sup -hat} of a quantum system undergoing both a preparation in a state ρ{sub i} and a postselection in a state E{sub f} is, to a good approximation, a function of the weak value A{sub w}=Tr[E{sub f}A{sup -hat} ρ{sub i}]/Tr[E{sub f}ρ{sub i}], a complex number. For a fixed coupling λ, when the overlap Tr[E{sub f}ρ{sub i}] is very small, A{sub w} diverges, but 〈o〉 stays finite, often tending to zero for symmetry reasons. This paper answers the questions: what is the weak value that maximizes the output for a fixed coupling? What is the coupling that maximizes the output for a fixed weak value? We derive equations for the optimal values of A{sub w} and λ, and provide the solutions. The results are independent of the dimensionality of the system, and they apply to a probe having a Hilbert space of arbitrary dimension. Using the Schrödinger–Robertson uncertainty relation, we demonstrate that, in an important case, the amplification 〈o〉 cannot exceed the initial uncertainty σ{sub o} in the observable o{sup -hat}, we provide an upper limit for the more general case, and a strategy to obtain 〈o〉≫σ{sub o}. - Highlights: •We have provided a general framework to find the extremal values of a weak measurement. •We have derived the location of the extremal values in terms of preparation and postselection. •We have devised a maximization strategy going beyond the limit of the Schrödinger–Robertson relation.

  2. Weak Coupling in 143Nd

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao-Hong; E, Ideguchi; T, Kishida; M, Ishihara; H, Tsuchida; Y, Gono; T, Morikawa; M, Shibata; H, Watanabe; M, Miyake; T, Tsutsumi; S, Motomura; S, Mitarai

    2000-04-01

    The high-spin states of 143Nd have been studied in the 130Te(18O, 5n)143Nd reaction at a beam energy of 80 MeV using techniques of in-beam γ-ray spectroscopy. Measurements of γ - γ - t coincidences, γ-ray angular distributions, and γ-ray linear polarizations were performed. A level scheme of 143Nd with spin and parity assignments up to 53/2+ is proposed. While a weak coupling model can explain the level structure up to the Jπ=39/2- state, this model can not reproduce the higher-lying states. Additionally, a new low-lying non-yrast level sequence in 143Nd was observed in the present work, which can be well described by the weak coupling of an i13/2 neutron to the 142Nd core nucleus.

  3. Overdamping by weakly coupled environments

    SciTech Connect

    Esposito, Massimiliano; Haake, Fritz

    2005-12-15

    A quantum system weakly interacting with a fast environment usually undergoes a relaxation with complex frequencies whose imaginary parts are damping rates quadratic in the coupling to the environment in accord with Fermi's 'golden rule'. We show for various models (spin damped by harmonic-oscillator or random-matrix baths, quantum diffusion, and quantum Brownian motion) that upon increasing the coupling up to a critical value still small enough to allow for weak-coupling Markovian master equations, a different relaxation regime can occur. In that regime, complex frequencies lose their real parts such that the process becomes overdamped. Our results call into question the standard belief that overdamping is exclusively a strong coupling feature.

  4. Optimizing SNAP for Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. W.; Ellis, R. S.; Massey, R. J.; Rhodes, J. D.; Lamoureux, J. I.; SNAP Collaboration

    2004-12-01

    The Supernova/Acceleration Probe (SNAP) satellite proposes to measure weak gravitational lensing in addition to type Ia supernovae. Its pixel scale has been set to 0.10 arcsec per pixel as established by the needs of supernova observations. To find the optimal pixel scale for accurate weak lensing measurements we conduct a tradeoff study in which, via simulations, we fix the suvey size in total pixels and vary the pixel scale. Our preliminary results show that with a smaller scale of about 0.08 arcsec per pixel we can minimize the contribution of intrinsic shear variance to the error on the power spectrum of mass density distortion. Currently we are testing the robustness of this figure as well as determining whether dithering yields analogous results.

  5. Leg Weakness Caused by Bilateral Piriformis Syndrome: A Case Report

    PubMed Central

    Moon, Hee Bong; Kwon, Bum Sun; Park, Jin Woo; Ryu, Gi Hyeong; Lee, Ho Jun; Kim, Chang Jae

    2015-01-01

    Piriformis syndrome (PS) is an uncommon neuromuscular disorder caused by the piriformis muscle (PM) compressing the sciatic nerve (SN). The main symptom of PS is sciatica, which worsens with certain triggering conditions. Because the pathophysiology is poorly understood, there are no definite diagnostic and therapeutic choices for PS. This case report presents a young woman who mainly complained of bilateral leg weakness. Electromyography revealed bilateral sciatic neuropathy and magnetic resonance imaging confirmed structural lesions causing entrapment of the bilateral SNs. After a laborious diagnosis of bilateral PS, she underwent PM releasing surgery. Few PS cases present with bilateral symptoms and leg weakness. Therefore, in such cases, a high level of suspicion is necessary for accurate and prompt diagnosis and treatment. PMID:26798622

  6. Morphological, Electrophysiological, and Metabolic Characteristics of Skeletal Muscle in People with End-Stage Renal Disease: A Critical Review

    PubMed Central

    Sawant, Anuradha; Garland, S. Jayne; House, Andrew A.

    2011-01-01

    ABSTRACT Purpose: Fatigue is one of the most frequent debilitating symptoms reported by people with end-stage renal disease (ESRD) on haemodialysis (HD) therapy. A wide range of underlying abnormalities, including skeletal muscle weakness, have been implicated as causes of this fatigue. Skeletal muscle weakness is well established in this population, and such muscle weakness is amenable to physical therapy treatment. The purpose of this review was to identify morphological, electrophysiological, and metabolic characteristics of skeletal muscles in people with ESRD/HD that may cause skeletal muscle weakness. Method: Electronic databases were searched for relevant literature from inception to March 2010. Inclusion criteria were English language; adult subjects with ESRD/HD; and the use of muscle biopsy, electromyography, and nuclear magnetic spectroscopy (31P-NMRS) techniques to evaluate muscle characteristics. Results: In total, 38 studies were included. All studies of morphological characteristics reported type II fibre atrophy. Electrophysiological characteristics included both neuropathic and myopathic skeletal muscle changes. Studies of metabolic characteristics revealed higher cytosolic inorganic phosphate levels and reduced effective muscle mass. Conclusion: The results indicate an array of changes in the morphological, electrophysiological, and metabolic characteristics of skeletal muscle structure in people with ESRD/HD that may lead to muscle weakness. PMID:22654242

  7. Advancements in stem cells treatment of skeletal muscle wasting

    PubMed Central

    Meregalli, Mirella; Farini, Andrea; Sitzia, Clementina; Torrente, Yvan

    2014-01-01

    Muscular dystrophies (MDs) are a heterogeneous group of inherited disorders, in which progressive muscle wasting and weakness is often associated with exhaustion of muscle regeneration potential. Although physiological properties of skeletal muscle tissue are now well known, no treatments are effective for these diseases. Muscle regeneration was attempted by means transplantation of myogenic cells (from myoblast to embryonic stem cells) and also by interfering with the malignant processes that originate in pathological tissues, such as uncontrolled fibrosis and inflammation. Taking into account the advances in the isolation of new subpopulation of stem cells and in the creation of artificial stem cell niches, we discuss how these emerging technologies offer great promises for therapeutic approaches to muscle diseases and muscle wasting associated with aging. PMID:24575052

  8. Pilot data: association between gluteus medius weakness and low back pain during pregnancy.

    PubMed

    Bewyer, Kathryn J; Bewyer, Dennis C; Messenger, Dana; Kennedy, Colleen M

    2009-01-01

    This cross-sectional study examines whether there is an association between gluteus medius weakness in the presence of low back pain in pregnant women at any stage of gestation. Prevalence of low back pain during pregnancy is high, and identifying potential etiologies and targeted interventions is lacking. Thus, identification of an association between specific muscle weakness and pain would have clinical relevance. Initial pilot data suggests that weakness of the gluteus medius is strongly associated with the presence of low back pain during pregnancy.

  9. Grip Strength Cutpoints for the Identification of Clinically Relevant Weakness

    PubMed Central

    Shardell, Michelle D.; Peters, Katherine W.; McLean, Robert R.; Dam, Thuy-Tien L.; Kenny, Anne M.; Fragala, Maren S.; Harris, Tamara B.; Kiel, Douglas P.; Guralnik, Jack M.; Ferrucci, Luigi; Kritchevsky, Stephen B.; Studenski, Stephanie A.; Vassileva, Maria T.; Cawthon, Peggy M.

    2014-01-01

    Background. Weakness is common and contributes to disability, but no consensus exists regarding a strength cutpoint to identify persons at high risk. This analysis, conducted as part of the Foundation for the National Institutes of Health Sarcopenia Project, sought to identify cutpoints that distinguish weakness associated with mobility impairment, defined as gait speed less than 0.8 m/s. Methods. In pooled cross-sectional data (9,897 men and 10,950 women), Classification and Regression Tree analysis was used to derive cutpoints for grip strength associated with mobility impairment. Results. In men, a grip strength of 26–32 kg was classified as “intermediate” and less than 26 kg as “weak”; 11% of men were intermediate and 5% were weak. Compared with men with normal strength, odds ratios for mobility impairment were 3.63 (95% CI: 3.01–4.38) and 7.62 (95% CI 6.13–9.49), respectively. In women, a grip strength of 16–20 kg was classified as “intermediate” and less than 16 kg as “weak”; 25% of women were intermediate and 18% were weak. Compared with women with normal strength, odds ratios for mobility impairment were 2.44 (95% CI 2.20–2.71) and 4.42 (95% CI 3.94–4.97), respectively. Weakness based on these cutpoints was associated with mobility impairment across subgroups based on age, body mass index, height, and disease status. Notably, in women, grip strength divided by body mass index provided better fit relative to grip strength alone, but fit was not sufficiently improved to merit different measures by gender and use of a more complex measure. Conclusions. Cutpoints for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function. PMID:24737558

  10. Channelopathies of skeletal muscle excitability

    PubMed Central

    Cannon, Stephen C.

    2016-01-01

    Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K+ levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are “channelopathies” caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1) and several potassium channels (Kir2.1, Kir2.6, Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics. PMID:25880512

  11. Oculopharyngeal Weakness, Hypophrenia, Deafness, and Impaired Vision: A Novel Autosomal Dominant Myopathy with Rimmed Vacuoles

    PubMed Central

    Chen, Ting; Lu, Xiang-Hui; Wang, Hui-Fang; Ban, Rui; Liu, Hua-Xu; Shi, Qiang; Wang, Qian; Yin, Xi; Pu, Chuan-Qiang

    2016-01-01

    Background: Myopathies with rimmed vacuoles are a heterogeneous group of muscle disorders with progressive muscle weakness and varied clinical manifestations but similar features in muscle biopsies. Here, we describe a novel autosomal dominant myopathy with rimmed vacuoles in a large family with 11 patients of three generations affected. Methods: A clinical study including family history, obstetric, pediatric, and development history was recorded. Clinical examinations including physical examination, electromyography (EMG), serum creatine kinase (CK), bone X-rays, and brain magnetic resonance imaging (MRI) were performed in this family. Open muscle biopsies were performed on the proband and his mother. To find the causative gene, the whole-exome sequencing was carried out. Results: Disease onset was from adolescence to adulthood, but the affected patients of the third generation presented an earlier onset and more severe clinical manifestations than the older generations. Clinical features were characterized as dysarthria, dysphagia, external ophthalmoplegia, limb weakness, hypophrenia, deafness, and impaired vision. However, not every patient manifested all symptoms. Serum CK was mildly elevated and EMG indicated a myopathic pattern. Brain MRI showed cerebellum and brain stem mildly atrophy. Rimmed vacuoles and inclusion bodies were observed in muscle biopsy. The whole-exome sequencing was performed, but the causative gene has not been found. Conclusions: We reported a novel autosomal dominant myopathy with rimmed vacuoles characterized by dysarthria, dysphagia, external ophthalmoplegia, limb weakness, hypophrenia, deafness, and impaired vision, but the causative gene has not been found and needs further study. PMID:27453229

  12. Mitochondrial ROS regulate oxidative damage and mitophagy but not age-related muscle fiber atrophy

    PubMed Central

    Sakellariou, Giorgos K.; Pearson, Timothy; Lightfoot, Adam P.; Nye, Gareth A.; Wells, Nicola; Giakoumaki, Ifigeneia I.; Vasilaki, Aphrodite; Griffiths, Richard D.; Jackson, Malcolm J.; McArdle, Anne

    2016-01-01

    Age-related loss of skeletal muscle mass and function is a major contributor to morbidity and has a profound effect on the quality of life of older people. The potential role of age-dependent mitochondrial dysfunction and cumulative oxidative stress as the underlying cause of muscle aging remains a controversial topic. Here we show that the pharmacological attenuation of age-related mitochondrial redox changes in muscle with SS31 is associated with some improvements in oxidative damage and mitophagy in muscles of old mice. However, this treatment failed to rescue the age-related muscle fiber atrophy associated with muscle atrophy and weakness. Collectively, these data imply that the muscle mitochondrial redox environment is not a key regulator of muscle fiber atrophy during sarcopenia but may play a key role in the decline of mitochondrial organelle integrity that occurs with muscle aging. PMID:27681159

  13. Conduction velocity of quiescent muscle fibers decreases during sustained contraction.

    PubMed

    Gazzoni, Marco; Camelia, Federico; Farina, Dario

    2005-07-01

    We tested the hypothesis that conduction velocity of quiescent muscle fibers decreases during sustained contraction due to the activity of the active motor units in the muscle. Ten subjects trained for the identification of a target motor unit in the abductor pollicis brevis with feedback on surface EMG signals detected with a two-dimensional array of 61 electrodes. The subjects activated the target motor unit in two 10-s long contractions, before (contraction C1) and after (C3) a 3-min contraction (C2), all in ischemic condition. The target motor unit was not activated during C2. Eight of the 10 subjects (control group) performed a second experimental session identical to the first but with a resting period of 3 min instead of the contraction C2. Exerted force and target motor unit discharge rate were not different between the two subject groups and between C1 and C3 (mean +/- SD, over C1 and C3; C2 group: 15.8 +/- 10.4% maximal voluntary contractions and 13.1 +/- 1.9 pps; control group: 15.6 +/- 22.1% maximal voluntary contractions and 14.5 +/- 1.9 pps, respectively). Muscle fiber conduction velocity of the target motor unit decreased in C3 with respect to C1 in the C2 group (3.59 +/- 0.57 and 3.34 +/- 0.47 m/s for C1 and C3, respectively; P < 0.05) but not in the control group (3.47 +/- 0.68 and 3.46 +/- 0.73 m/s). In the C2 group, the percent decrease in conduction velocity of the target motor unit between C1 and C3 (6.4 +/- 7.1%) was not significantly different from the percent decrease in the average conduction velocity of the motor units active during C2 (9.6 +/- 5.4%). In conclusion, the contraction-induced modifications in electrophysiological membrane properties of muscle fibers are partly independent on fiber activation.

  14. Analysis of muscle fatigue in helicopter pilots.

    PubMed

    Balasubramanian, Venkatesh; Dutt, Ashwani; Rai, Shobhit

    2011-11-01

    Helicopter pilots espouse ergonomically unfavourable postures and endure vibration which result in low back pain. The objective of this study was to investigate the effects of a helicopter flight on pilots back and shoulder muscles using surface Electromyography (sEMG) analysis. This study also correlates low back pain symptoms from Rehabilitation Bioengineering Group Pain Scale (RBGPS) questionnaire with muscle fatigue rates obtained. RBGPS was administered on 20 Coast Guard helicopter pilots. sEMG was acquired before and after flight from erector spinae and trapezius muscles in 8 of these 20 pilots. Statistical analysis of time and frequency domain parameters indicated significant fatigue in right trapezius muscle due to flying. Muscle fatigue correlated with average duration of flight (r² = 0.913), total service as pilot (r² = 0.825), pain (r² = 0.463) and total flying hours (r² = 0.507). However, muscle fatigue weakly correlated with Body Mass Index (BMI) (r² = 0.000144) and age (r² = 0.033).

  15. Analysis of muscle fatigue in helicopter pilots.

    PubMed

    Balasubramanian, Venkatesh; Dutt, Ashwani; Rai, Shobhit

    2011-11-01

    Helicopter pilots espouse ergonomically unfavourable postures and endure vibration which result in low back pain. The objective of this study was to investigate the effects of a helicopter flight on pilots back and shoulder muscles using surface Electromyography (sEMG) analysis. This study also correlates low back pain symptoms from Rehabilitation Bioengineering Group Pain Scale (RBGPS) questionnaire with muscle fatigue rates obtained. RBGPS was administered on 20 Coast Guard helicopter pilots. sEMG was acquired before and after flight from erector spinae and trapezius muscles in 8 of these 20 pilots. Statistical analysis of time and frequency domain parameters indicated significant fatigue in right trapezius muscle due to flying. Muscle fatigue correlated with average duration of flight (r² = 0.913), total service as pilot (r² = 0.825), pain (r² = 0.463) and total flying hours (r² = 0.507). However, muscle fatigue weakly correlated with Body Mass Index (BMI) (r² = 0.000144) and age (r² = 0.033). PMID:21411058

  16. Unusual fibularis (peroneus) muscle.

    PubMed

    Fabrizio, Philip A

    2015-10-01

    Routine dissection has identified a previously unrecorded fibularis (peroneus) muscle in a 74-year-old male cadaver. The anomalous fibularis muscle was found lying immediately antero-medial to the fibularis longus (FL) muscle of the left leg. The anomalous muscle arose from the muscle belly of the FL in the proximal 1/2 of the leg. The muscle belly gave way to a long slender tendon that continued distally behind the lateral malleolus and inserted onto the superficial aspect of the inferior fibular retinaculum. The current finding and clinical significance are discussed.

  17. Decoding upper limb residual muscle activity in severe chronic stroke

    PubMed Central

    Ramos-Murguialday, Ander; García-Cossio, Eliana; Walter, Armin; Cho, Woosang; Broetz, Doris; Bogdan, Martin; Cohen, Leonardo G; Birbaumer, Niels

    2015-01-01

    Objective Stroke is a leading cause of long-term motor disability. Stroke patients with severe hand weakness do not profit from rehabilitative treatments. Recently, brain-controlled robotics and sequential functional electrical stimulation allowed some improvement. However, for such therapies to succeed, it is required to decode patients' intentions for different arm movements. Here, we evaluated whether residual muscle activity could be used to predict movements from paralyzed joints in severely impaired chronic stroke patients. Methods Muscle activity was recorded with surface-electromyography (EMG) in 41 patients, with severe hand weakness (Fugl-Meyer Assessment [FMA] hand subscores of 2.93 ± 2.7), in order to decode their intention to perform six different motions of the affected arm, required for voluntary muscle activity and to control neuroprostheses. Decoding of paretic and nonparetic muscle activity was performed using a feed-forward neural network classifier. The contribution of each muscle to the intended movement was determined. Results Decoding of up to six arm movements was accurate (>65%) in more than 97% of nonparetic and 46% of paretic muscles. Interpretation These results demonstrate that some level of neuronal innervation to the paretic muscle remains preserved and can be used to implement neurorehabilitative treatments in 46% of patients with severe paralysis and extensive cortical and/or subcortical lesions. Such decoding may allow these patients for the first time after stroke to control different motions of arm prostheses through muscle-triggered rehabilitative treatments. PMID:25642429

  18. Detecting weakly interacting massive particles.

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Gelmini, G. B.

    The growing synergy between astrophysics, particle physics, and low background experiments strengthens the possibility of detecting astrophysical non-baryonic matter. The idea of direct detection is that an incident, massive weakly interacting particle could collide with a nucleus and transfer an energy that could be measured. The present low levels of background achieved by the PNL/USC Ge detector represent a new technology which yields interesting bounds on Galactic cold dark matter and on light bosons emitted from the Sun. Further improvements require the development of cryogenic detectors. The authors analyse the practicality of such detectors, their optimalization and background suppression using the "annual modulation effect".

  19. Weak lensing by galaxy troughs

    NASA Astrophysics Data System (ADS)

    Gruen, Daniel

    2016-06-01

    Galaxy troughs, i.e. underdensities in the projected galaxy field, are a weak lensing probe of the low density Universe with high signal-to-noise ratio. I present measurements of the radial distortion of background galaxy images and the de-magnification of the CMB by troughs constructed from Dark Energy Survey and Sloan Digital Sky Survey galaxy catalogs. With high statistical significance and a relatively robust modeling, these probe gravity in regimes of density and scale difficult to access for conventional statistics.

  20. Weak quasielastic production of hyperons

    SciTech Connect

    Singh, S. K.; Vacas, M. J. Vicente

    2006-09-01

    The quasielastic weak production of {lambda} and {sigma} hyperons from nucleons and nuclei induced by antineutrinos is studied in the energy region of some ongoing neutrino oscillation experiments in the intermediate energy region. The hyperon-nucleon transition form factors determined from neutrino-nucleon scattering and an analysis of high precision data on semileptonic decays of neutron and hyperons using SU(3) symmetry have been used. The nuclear effects due to Fermi motion and final state interaction effects due to hyperon-nucleon scattering have also been studied. The numerical results for differential and total cross sections have been presented.

  1. Tagged-weak {pi} method

    SciTech Connect

    Margaryan, A.; Hashimoto, O.; Kakoyan, V.; Knyazyan, S.; Tang, L.

    2011-02-15

    A new 'tagged-weak {pi} method' is proposed for determination of electromagnetic transition probabilities B(E2) and B(M1) of the hypernuclear states with lifetimes of {approx}10{sup -10} s. With this method, we are planning to measure B(E2) and B(M1) for light hypernuclei at JLab. The results of Monte Carlo simulations for the case of E2(5/2{sup +}, 3/2{sup +} {yields} 1/2{sup +}) transitions in {sub {Lambda}}{sup 7}He hypernuclei are presented.

  2. Human Muscle Fiber

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The stimulus of gravity affects RNA production, which helps maintain the strength of human muscles on Earth (top), as seen in this section of muscle fiber taken from an astronaut before spaceflight. Astronauts in orbit and patients on Earth fighting muscle-wasting diseases need countermeasures to prevent muscle atrophy, indicated here with white lipid droplets (bottom) in the muscle sample taken from the same astronaut after spaceflight. Kerneth Baldwin of the University of California, Irvine, is conducting research on how reducing the stimulus of gravity affects production of the RNA that the body uses as a blueprint for making muscle proteins. Muscle proteins are what give muscles their strength, so when the RNA blueprints aren't available for producing new proteins to replace old ones -- a situation that occurs in microgravity -- the muscles atrophy. When the skeletal muscle system is exposed to microgravity during spaceflight, the muscles undergo a reduced mass that translates to a reduction in strength. When this happens, muscle endurance decreases and the muscles are more prone to injury, so individuals could have problems in performing extravehicular activity [space walks] or emergency egress because their bodies are functionally compromised.

  3. Reliability of new software in measuring cervical multifidus diameters and shoulder muscle strength in a synchronized way; an ultrasonographic study

    PubMed Central

    Rahnama, Leila; Rezasoltani, Asghar; Khalkhali-Zavieh, Minoo; Rahnama, Behnam; Noori-Kochi, Farhang

    2015-01-01

    OBJECTIVES: This study was conducted with the purpose of evaluating the inter-session reliability of new software to measure the diameters of the cervical multifidus muscle (CMM), both at rest and during isometric contractions of the shoulder abductors in subjects with neck pain and in healthy individuals. METHOD: In the present study, the reliability of measuring the diameters of the CMM with the Sonosynch software was evaluated by using 24 participants, including 12 subjects with chronic neck pain and 12 healthy individuals. The anterior-posterior diameter (APD) and the lateral diameter (LD) of the CMM were measured in a resting state and then repeated during isometric contraction of the shoulder abductors. Measurements were taken on separate occasions 3 to 7 days apart in order to determine inter-session reliability. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and smallest detectable difference (SDD) were used to evaluate the relative and absolute reliability, respectively. RESULTS: The Sonosynch software has shown to be highly reliable in measuring the diameters of the CMM both in healthy subjects and in those with neck pain. The ICCs 95% CI for APD ranged from 0.84 to 0.94 in subjects with neck pain and from 0.86 to 0.94 in healthy subjects. For LD, the ICC 95% CI ranged from 0.64 to 0.95 in subjects with neck pain and from 0.82 to 0.92 in healthy subjects. CONCLUSIONS: Ultrasonographic measurement of the diameters of the CMM using Sonosynch has proved to be reliable especially for APD in healthy subjects as well as subjects with neck pain. PMID:26443975

  4. Muscle strain injuries.

    PubMed

    Garrett, W E

    1996-01-01

    One of the most common injuries seen in the office of the practicing physician is the muscle strain. Until recently, little data were available on the basic science and clinical application of this basic science for the treatment and prevention of muscle strains. Studies in the last 10 years represent action taken on the direction of investigation into muscle strain injuries from the laboratory and clinical fronts. Findings from the laboratory indicate that certain muscles are susceptible to strain injury (muscles that cross multiple joints or have complex architecture). These muscles have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone, rather, strains are the result of excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is localized very near the muscle-tendon junction. After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing. Current imaging studies have been used clinically to document the site of injury to the muscle-tendon junction. The commonly injured muscles have been described and include the hamstring, the rectus femoris, gastrocnemius, and adductor longus muscles. Injuries inconsistent with involvement of a single muscle-tendon junction proved to be at tendinous origins rather than within the muscle belly. Important information has also been provided regarding injuries with poor prognosis, which are potentially repairable surgically, including injuries to the rectus femoris muscle, the hamstring origin, and the abdominal wall. Data important to the management of common muscle injuries have been published. The risks of reinjury have been documented. The early efficacy and potential for long-term risks of nonsteroidal antiinflammatory agents have been shown. New data can also be applied to the field

  5. Treatment of Progressive First Metatarsophalangeal Hallux Valgus Deformity: A Biomechanically Based Muscle-Strengthening Approach.

    PubMed

    Glasoe, Ward M

    2016-07-01

    Synopsis Hallux valgus is a progressive deformity of the first metatarsophalangeal joint that changes the anatomy and biomechanics of the foot. To date, surgery is the only treatment to correct this deformity, though the recurrence rate is as high as 15%. This clinical commentary provides instruction in a strengthening approach for treatment of hallux valgus deformity, by addressing the moment actions of 5 muscles identified as having the ability to counter the hallux valgus process. Unlike surgery, muscle strengthening does not correct the deformity, but, instead, reduces the pain and associated gait impairments that affect the mobility of people who live with the disorder. This review is organized in 4 parts. Part 1 defines the terms of foot motion and posture. Part 2 details the anatomy and biomechanics, and describes how the foot is changed with deformity. Part 3 details the muscles targeted for strengthening; the intrinsics being the abductor hallucis, adductor hallucis, and the flexor hallucis brevis; the extrinsics being the tibialis posterior and fibularis longus. Part 4 instructs the exercise and reviews the related literature. Instructions are given for the short-foot, the toe-spread-out, and the heel-raise exercises. The routine may be performed by almost anyone at home and may be adopted into physical therapist practice, with intent to strengthen the foot muscles as an adjunct to almost any protocol of care, but especially for the treatment of hallux valgus deformity. J Orthop Sports Phys Ther 2016;46(7):596-605. Epub 6 Jun 2016. doi:10.2519/jospt.2016.6704. PMID:27266887

  6. The weak scale from BBN

    NASA Astrophysics Data System (ADS)

    Hall, Lawrence J.; Pinner, David; Ruderman, Joshua T.

    2014-12-01

    The measured values of the weak scale, v, and the first generation masses, m u, d, e , are simultaneously explained in the multiverse, with all these parameters scanning independently. At the same time, several remarkable coincidences are understood. Small variations in these parameters away from their measured values lead to the instability of hydrogen, the instability of heavy nuclei, and either a hydrogen or a helium dominated universe from Big Bang Nucleosynthesis. In the 4d parameter space of ( m u , m d , m e , v), catastrophic boundaries are reached by separately increasing each parameter above its measured value by a factor of (1.4, 1.3, 2.5, ˜ 5), respectively. The fine-tuning problem of the weak scale in the Standard Model is solved: as v is increased beyond the observed value, it is impossible to maintain a significant cosmological hydrogen abundance for any values of m u, d, e that yield both hydrogen and heavy nuclei stability.

  7. Weak antilocalisation in topological insulators

    NASA Astrophysics Data System (ADS)

    Bi, Xintao; Hankiewicz, Ewelina; Culcer, Dimitrie

    2014-03-01

    Topological insulators (TI) have changed our understanding of insulating behaviour. They are insulators in the bulk but conducting along their surfaces due to spin-orbit interaction. Much of the recent research focuses on overcoming the transport bottleneck, the fact that surface state transport is overwhelmed by bulk transport stemming from unintentional doping. The key to overcoming this bottleneck is identifying unambiguous signatures of surface state transport. This talk will discuss one such signature, which is manifest in the coherent backscattering of electrons. Due to strong spin-orbit coupling in TI one expects to observe weak antilocalisation rather than weak localisation, meaning that coherent backscattering increases the electrical conductivity. The features of this effect, however, are rather subtle, because in TI the impurities have strong spin-orbit coupling as well. I will show that spin-orbit coupled impurities introduce an additional time scale, which is expected to be shorter than the dephasing time, and the resulting conductivity has a logarithmic dependence on the carrier density, a behaviour hitherto unknown in 2D electron systems. The result we predict is observable experimentally and would provide a smoking gun test of surface transport.

  8. Weak lensing and cosmological investigation

    NASA Astrophysics Data System (ADS)

    Acquaviva, Viviana

    2005-03-01

    In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the Cosmic Microwave Background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l ~= 1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended theories of gravity, introducing the physical observables suitable to cast the bridge between lensing and cosmology, and then evaluate the amplitude of the expected effect in the particular case of a Non-Minimally-Coupled model, featuring a quadratic coupling between quintessence and Ricci scalar.

  9. Muscle autoantibodies in myasthenia gravis: beyond diagnosis?

    PubMed Central

    Meriggioli, Matthew N; Sanders, Donald B

    2012-01-01

    Myasthenia gravis is an autoimmune disorder of the neuromuscular junction. A number of molecules, including ion channels and other proteins at the neuromuscular junction, may be targeted by autoantibodies leading to abnormal neuromuscular transmission. In approximately 85% of patients, autoantibodies, directed against the postsynaptic nicotinic acetylcholine receptor can be detected in the serum and confirm the diagnosis, but in general, do not precisely predict the degree of weakness or response to therapy. Antibodies to the muscle-specific tyrosine kinase are detected in approximately 50% of generalized myasthenia gravis patients who are seronegative for anti-acetylcholine receptor antibodies, and levels of anti-muscle-specific tyrosine kinase antibodies do appear to correlate with disease severity and treatment response. Antibodies to other muscle antigens may be found in the subsets of myasthenia gravis patients, potentially providing clinically useful diagnostic information, but their utility as relevant biomarkers (measures of disease state or response to treatment) is currently unclear. PMID:22882218

  10. Healthy Muscles Matter

    MedlinePlus

    ... keep my muscles more healthy? Definitions What can go wrong? Injuries Almost everyone has had sore muscles ... If you have been inactive, “start low and go slow” by gradually increasing how often and how ...

  11. Eye muscle repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100062.htm Eye muscle repair - series—Normal anatomy To use the sharing ... the eyeball to the eye socket. The external muscles of the eye are found behind the conjunctiva. ...

  12. Aging related changes in determinants of muscle force generating capacity: a comparison of muscle aging in men and male rodents.

    PubMed

    Ballak, Sam B; Degens, Hans; de Haan, Arnold; Jaspers, Richard T

    2014-03-01

    Human aging is associated with a progressive decline in skeletal muscle mass and force generating capacity, however the exact mechanisms underlying these changes are not fully understood. Rodents models have often been used to enhance our understanding of mechanisms of age-related changes in human skeletal muscle. However, to what extent age-related alterations in determinants of muscle force generating capacity observed in rodents resemble those in humans has not been considered thoroughly. This review compares the effect of aging on muscle force generating determinants (muscle mass, fiber size, fiber number, fiber type distribution and muscle specific tension), in men and male rodents at similar relative age. It appears that muscle aging in male F344*BN rat resembles that in men most; 32-35-month-old rats exhibit similar signs of muscle weakness to those of 70-80-yr-old men, and the decline in 36-38-month-old rats is similar to that in men aged over 80 yrs. For male C57BL/6 mice, age-related decline in muscle force generating capacity seems to occur only at higher relative age than in men. We conclude that the effects on determinants of muscle force differ between species as well as within species, but qualitatively show the same pattern as that observed in men.

  13. Leucine-enriched essential amino acids attenuate muscle soreness and improve muscle protein synthesis after eccentric contractions in rats.

    PubMed

    Kato, Hiroyuki; Suzuki, Hiromi; Mimura, Masako; Inoue, Yoshiko; Sugita, Mayu; Suzuki, Katsuya; Kobayashi, Hisamine

    2015-06-01

    Eccentric exercise results in prolonged muscle weakness and muscle soreness, which are typical symptoms of muscle damage. Recovery from muscle damage is related to mammalian target of rapamycin (mTOR) activity. Leucine-enriched essential amino acids (LEAAs) stimulate muscle protein synthesis via activation of the mTOR pathway. Therefore, we investigated the effect of LEAAs on muscle protein synthesis and muscle soreness after eccentric contractions (EC). Male Sprague-Dawley rats (9-11 weeks old) were administered an LEAA solution (AminoL40; containing 40 % leucine and 60 % other essential amino acids) at 1 g/kg body weight or distilled water (control) 30 min before and 10 min after EC. Tibialis anterior (TA) muscle was exposed to 500 EC by electrical stimulation under anesthesia. The fractional synthesis rate (FSR; %/h) in the TA muscle was measured by incorporating L-[ring-(2)H5] phenylalanine into skeletal muscle protein. Muscle soreness was evaluated by the paw withdrawal threshold using the Randal-Selitto test with some modifications from 1 to 3 days after EC. The FSR in the EC-control group (0.147 ± 0.016 %/h) was significantly lower than in the sedentary group (0.188 ± 0.016 %/h, p < 0.05). AminoL40 administration significantly mitigated the EC-induced impairment of the FSR (0.172 ± 0.018 %/h). EC decreased the paw withdrawal threshold at 1 and 2 days after EC, which indicated that EC induced muscle soreness. Furthermore, AminoL40 administration alleviated the decreased paw withdrawal threshold. These findings suggest that LEAA supplementation improves the rate of muscle protein synthesis and ameliorates muscle soreness after eccentric exercise. PMID:25772815

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

    PubMed

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

    2016-06-01

    Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated. PMID:26667010

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

    PubMed

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

    2016-06-01

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

  16. Effect of vitamin D on skeletal muscle.

    PubMed

    Walrand, Stéphane

    2016-06-01

    Beyond its traditional biological roles on bone health, extra-skeletal effects of vitamin D are currently under extensive research. The expression of the vitamin D receptor in most tissues has also strengthened the argument for its multiple functions. Among these, the effect of vitamin D on the mass and muscle performance has long been discussed. In ancient Greece, Herodotus recommended the sun as a cure for the "weak and soft muscles" and former Olympians exposed to sunlight to improve their physical performance. In 1952, Dr Spellerberg, a sports physiologist, has conducted an extensive study on the effects of UV irradiation on the performance of elite athletes. Following the significant results of this investigation, the scientist has informed the Olympic Committee that UV irradiation had a "persuasive" effect on physical performance and motor skills. These data are consistent with many subsequent studies reporting an improvement in physical activity, speed and endurance in young subjects treated with UV or with supplements containing vitamin D. Additional observation indicates a significant effect on muscle strength, particularly in the lower limbs. Concerning the mechanisms involved, some recent fundamental studies have shown that vitamin D exerts some molecular effects within the muscle cell. Specifically, a regulatory effect of vitamin D on calcium flux, mineral homeostasis and signaling pathways controlling protein anabolism has been reported in muscle tissue. Several epidemiological studies show that low vitamin D status is always associated with a decrease in muscle mass, strength and contractile capacity in older people. Vitamin D deficiency accelerates muscle loss with age (sarcopenia), and therefore leads to a reduction in physical capacity and to an increased risk of falls and fractures. In contrast, an additional intake of vitamin D in older people significantly improves muscle function and physical performance. PMID:27100224

  17. Atypical Pectoralis Major Muscle Wasting in a Recreational Weight Lifter.

    PubMed

    Parnes, Nata; Blevins, Maryellen I; Carey, Paul; Friedman, Darren J

    2016-07-01

    Pectoralis major injuries are relatively uncommon and can pose a diagnostic challenge. Deformity and weakness of this muscle in weight lifters is typically due to traumatic tendon rupture and often requires surgical repair. However, there are other less common etiologies that can mimic the clinical presentation of pectoralis major wasting and weakness that require different treatment approaches. This article describes a case of a 48-year-old recreational weight lifter who presented with severe pectoralis major wasting and weakness secondary to isolated mononeuropathy of the lateral pectoral nerve possibly due to Parsonage Turner syndrome. The patient was treated nonoperatively and achieved full recovery 18 months after onset. Parsonage Turner syndrome should be included in the differential diagnosis of patients with atraumatic weakness and wasting of the pectoralis major muscle and dysfunction. [Orthopedics. 2016; 39(4):e756-e759.]. PMID:27280627

  18. Kinetics and thermodynamics of lactate dehydrogenases from beef heart, beef muscle, and flounder muscle.

    PubMed

    Borgmann, U; Laidler, K J; Moon, T W

    1975-11-01

    The eight rate constants for a four-step ordered ternary-complex mechanism have been compared for lactate dehydrogenases (EC1.1.1.27) from three sources, beef heart, beef muscle, and flounder muscle. The rate constants were determined at temperatures ranging from 5 degrees C to 50 degrees C, and the corresponding activation parameters deltaG not equal to, deltaH not equal to, and deltaS not equal to were calculated. Significant differences are noted for the values for the three types of enzyme. The relative heights of the activation barriers are much the same in all three cases, differences in kinetic behavior resulting mainly from differences in the stable binary and ternary enzyme-substrate complexes. These complexes are, in general, at lower free-energy and enthalpy levels of the beef-heart and beef-muscle enzymes than for the flounder-muscle enzyme. A high degree of compensation is found between the enthalpies and entropies of activation, resulting in relatively small differences between the free energies (and rates) for homologous steps with different enzymes. Analysis of the results, on the assumption that the compensation effect is due to weak-bonding effects, suggests that there are fewer weak bonds in the stable complexes of the muscle enzymes.

  19. Muscle Session Summary

    NASA Technical Reports Server (NTRS)

    Baldwin, Kenneth; Feeback, Daniel

    1999-01-01

    Presentations from the assembled group of investigators involved in specific research projeects related to skeletal muscle in space flight can categorized in thematic subtopics: regulation of contractile protein phenotypes, muscle growth and atrophy, muscle structure: injury, recovery,and regeneration, metabolism and fatigue, and motor control and loading factors.

  20. Heterogeneous, weakly coupled map lattices

    NASA Astrophysics Data System (ADS)

    Sotelo Herrera, M.a. Dolores; San Martín, Jesús; Porter, Mason A.

    2016-07-01

    Coupled map lattices (CMLs) are often used to study emergent phenomena in nature. It is typically assumed (unrealistically) that each component is described by the same map, and it is important to relax this assumption. In this paper, we characterize periodic orbits and the laminar regime of type-I intermittency in heterogeneous weakly coupled map lattices (HWCMLs). We show that the period of a cycle in an HWCML is preserved for arbitrarily small coupling strengths even when an associated uncoupled oscillator would experience a period-doubling cascade. Our results characterize periodic orbits both near and far from saddle-node bifurcations, and we thereby provide a key step for examining the bifurcation structure of heterogeneous CMLs.

  1. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.894 Weak. Weak means... content, inferior flavor, or are of poor keeping quality....

  2. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.894 Weak. Weak means that individual berries are somewhat translucent, watery and soft, may have relatively low...

  3. 7 CFR 51.894 - Weak.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.894 Weak. Weak means that individual berries are somewhat translucent, watery and soft, may have relatively low...

  4. Deterministic weak localization in periodic structures.

    PubMed

    Tian, C; Larkin, A

    2005-12-01

    In some perfect periodic structures classical motion exhibits deterministic diffusion. For such systems we present the weak localization theory. As a manifestation for the velocity autocorrelation function a universal power law decay is predicted to appear at four Ehrenfest times. This deterministic weak localization is robust against weak quenched disorders, which may be confirmed by coherent backscattering measurements of periodic photonic crystals.

  5. Muscle satellite cell heterogeneity and self-renewal.

    PubMed

    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.

  6. Glucocorticoids and Skeletal Muscle.

    PubMed

    Bodine, Sue C; Furlow, J David

    2015-01-01

    Glucocorticoids are known to regulate protein metabolism in skeletal muscle, producing a catabolic effect that is opposite that of insulin. In many catabolic diseases, such as sepsis, starvation, and cancer cachexia, endogenous glucocorticoids are elevated contributing to the loss of muscle mass and function. Further, exogenous glucocorticoids are often given acutely and chronically to treat inflammatory conditions such as asthma, chronic obstructive pulmonary disease, and rheumatoid arthritis, resulting in muscle atrophy. This chapter will detail the nature of glucocorticoid-induced muscle atrophy and discuss the mechanisms thought to be responsible for the catabolic effects of glucocorticoids on muscle. PMID:26215994

  7. Oxidative Metabolism in Muscle

    NASA Astrophysics Data System (ADS)

    Ferrari, M.; Binzoni, T.; Quaresima, V.

    1997-06-01

    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 advantages and problems of near-infrared spectroscopy measurements, in resting and exercising skeletal muscles studies, are discussed through some representative examples.

  8. Internal organization in the human jaw muscles.

    PubMed

    Hannam, A G; McMillan, A S

    1994-01-01

    The human jaw muscles are essential to mastication and play an important part in craniofacial growth. They contribute to dental and articular forces, deform the mandible, and, like other tissues, are subject to disorders, often manifested as pain. The literature describes how their contraction is controlled by the nervous system, and how their general structure and function contribute to craniofacial biology, but there has been little appraisal of their internal organization. Most of these muscles are not simple; they are multipennate, complexly layered, and divided by aponeuroses. This arrangement provides substantial means for differential contraction. In many ways, jaw muscle fibers are intrinsically dissimilar from those found in other skeletal muscles, because they are arranged in homogeneous clusters and generally reveal type I or type II histochemical profiles. Most are type I and are distributed preferentially in the anterior and deeper parts of the jaw closers. Additionally, most motor unit (MU) territories are smaller than those in the limbs. There is circumstantial evidence for intramuscular partitioning based in part on innervation by primary muscle nerve branches. During normal function. MU recruitment and the rate coding of MU firing in human jaw muscles follow the general principles established for the limbs, but even here they differ in important respects. Jaw muscle MUs do not have stable force recruitment thresholds and seem to rely more on rate coding than on sequential unit recruitment to grade the amplitude of muscle contraction. Unlike those in the limbs, their twitch tensions correlate weakly with MU fatiguability and contraction speed, probably because there are so few slow, fatigue-resistant MUs in the jaw muscles. Moreover, the type I fibers that are present in such large numbers do not contract as slowly as normally expected. To complicate matters, estimation of jaw MU twitch tensions is extremely difficult, because it is affected by the

  9. Lower limb muscle impairment in myotonic dystrophy type 1: the need for better guidelines.

    PubMed

    Petitclerc, Émilie; Hébert, Luc J; Desrosiers, Johanne; Gagnon, Cynthia

    2015-04-01

    In myotonic dystrophy type 1 (DM1), leg muscle weakness is a major impairment. There are challenges to obtaining a clear portrait of muscle strength impairment. A systematic literature review was conducted on lower limb strength impairment in late-onset and adult phenotypes to document variables which affect strength measurement. Thirty-two articles were reviewed using the COSMIN guidelines. Only a third of the studies described a reproducible protocol. Only 2 muscle groups have documented reliability for quantitative muscle testing and only 1 total score for manual muscle testing. Variables affecting muscle strength impairment are not described in most studies. This review illustrates the variability in muscle strength assessment in relation to DM1 characteristics and the questionable validity of the results with regard to undocumented methodological properties. There is therefore a clear need to adopt a consensus on the use of a standardized muscle strength assessment protocol.

  10. Collagen VI deficiency reduces muscle pathology, but does not improve muscle function, in the γ-sarcoglycan-null mouse

    PubMed Central

    de Greef, Jessica C.; Hamlyn, Rebecca; Jensen, Braden S.; O'Campo Landa, Raul; Levy, Jennifer R.; Kobuke, Kazuhiro; Campbell, Kevin P.

    2016-01-01

    Muscular dystrophy is characterized by progressive skeletal muscle weakness and dystrophic muscle exhibits degeneration and regeneration of muscle cells, inflammation and fibrosis. Skeletal muscle fibrosis is an excessive deposition of components of the extracellular matrix including an accumulation of Collagen VI. We hypothesized that a reduction of Collagen VI in a muscular dystrophy model that presents with fibrosis would result in reduced muscle pathology and improved muscle function. To test this hypothesis, we crossed γ-sarcoglycan-null mice, a model of limb-girdle muscular dystrophy type 2C, with a Col6a2-deficient mouse model. We found that the resulting γ-sarcoglycan-null/Col6a2Δex5 mice indeed exhibit reduced muscle pathology compared with γ-sarcoglycan-null mice. Specifically, fewer muscle fibers are degenerating, fiber size varies less, Evans blue dye uptake is reduced and serum creatine kinase levels are lower. Surprisingly, in spite of this reduction in muscle pathology, muscle function is not significantly improved. In fact, grip strength and maximum isometric tetanic force are even lower in γ-sarcoglycan-null/Col6a2Δex5 mice than in γ-sarcoglycan-null mice. In conclusion, our results reveal that Collagen VI-mediated fibrosis contributes to skeletal muscle pathology in γ-sarcoglycan-null mice. Importantly, however, our data also demonstrate that a reduction in skeletal muscle pathology does not necessarily lead to an improvement of skeletal muscle function, and this should be considered in future translational studies. PMID:26908621

  11. Muscle formation during embryogenesis of the polychaete Ophryotrocha diadema (Dorvilleidae) – new insights into annelid muscle patterns

    PubMed Central

    Bergter, Annette; Brubacher, John L; Paululat, Achim

    2008-01-01

    Background The standard textbook information that annelid musculature consists of oligochaete-like outer circular and inner longitudinal muscle-layers has recently been called into question by observations of a variety of complex muscle systems in numerous polychaete taxa. To clarify the ancestral muscle arrangement in this taxon, we compared myogenetic patterns during embryogenesis of Ophryotrocha diadema with available data on oligochaete and polychaete myogenesis. This work addresses the conflicting views on the ground pattern of annelids, and adds to our knowledge of the evolution of lophotrochozoan taxa. Results Somatic musculature in Ophryotrocha diadema can be classified into the trunk, prostomial/peristomial, and parapodial muscle complexes. The trunk muscles comprise strong bilateral pairs of distinct dorsal and ventral longitudinal strands. The latter are the first to differentiate during myogenesis. They originate within the peristomium and grow posteriorly through the continuous addition of myocytes. Later, the longitudinal muscles also expand anteriorly and form a complex arrangement of prostomial muscles. Four embryonic parapodia differentiate in an anterior-to-posterior progression, significantly contributing to the somatic musculature. Several diagonal and transverse muscles are present dorsally. Some of the latter are situated external to the longitudinal muscles, which implies they are homologous to the circular muscles of oligochaetes. These circular fibers are only weakly developed, and do not appear to form complete muscle circles. Conclusion Comparison of embryonic muscle patterns showed distinct similarities between myogenetic processes in Ophryotrocha diadema and those of oligochaete species, which allows us to relate the diverse adult muscle arrangements of these annelid taxa to each other. These findings provide significant clues for the interpretation of evolutionary changes in annelid musculature. PMID:18171469

  12. Satellite cells from dystrophic muscle retain regenerative capacity.

    PubMed

    Boldrin, Luisa; Zammit, Peter S; Morgan, Jennifer E

    2015-01-01

    Duchenne muscular dystrophy is an inherited disorder that is characterized by progressive skeletal muscle weakness and wasting, with a failure of muscle maintenance/repair mediated by satellite cells (muscle stem cells). The function of skeletal muscle stem cells resident in dystrophic muscle may be perturbed by being in an increasing pathogenic environment, coupled with constant demands for repairing muscle. To investigate the contribution of satellite cell exhaustion to this process, we tested the functionality of satellite cells isolated from the mdx mouse model of Duchenne muscular dystrophy. We found that satellite cells derived from young mdx mice contributed efficiently to muscle regeneration within our in vivo mouse model. To then test the effects of long-term residence in a dystrophic environment, satellite cells were isolated from aged mdx muscle. Surprisingly, they were as functional as those derived from young or aged wild type donors. Removing satellite cells from a dystrophic milieu reveals that their regenerative capacity remains both intact and similar to satellite cells derived from healthy muscle, indicating that the host environment is critical for controlling satellite cell function.

  13. Age-dependent motor unit remodelling in human limb muscles.

    PubMed

    Piasecki, Mathew; Ireland, Alex; Jones, David A; McPhee, Jamie S

    2016-06-01

    Voluntary control of skeletal muscle enables humans to interact with and manipulate the environment. Lower muscle mass, weakness and poor coordination are common complaints in older age and reduce physical capabilities. Attention has focused on ways of maintaining muscle size and strength by exercise, diet or hormone replacement. Without appropriate neural innervation, however, muscle cannot function. Emerging evidence points to a neural basis of muscle loss. Motor unit number estimates indicate that by age around 71 years, healthy older people have around 40 % fewer motor units. The surviving low- and moderate-threshold motor units recruited for moderate intensity contractions are enlarged by around 50 % and show increased fibre density, presumably due to collateral reinnervation of denervated fibres. Motor unit potentials show increased complexity and the stability of neuromuscular junction transmissions is decreased. The available evidence is limited by a lack of longitudinal studies, relatively small sample sizes, a tendency to examine the small peripheral muscles and relatively few investigations into the consequences of motor unit remodelling for muscle size and control of movements in older age. Loss of motor neurons and remodelling of surviving motor units constitutes the major change in ageing muscles and probably contributes to muscle loss and functional impairments. The deterioration and remodelling of motor units likely imposes constraints on the way in which the central nervous system controls movements. PMID:26667009

  14. Exercise and nutritional interventions for improving aging muscle health.

    PubMed

    Forbes, Scott C; Little, Jonathan P; Candow, Darren G

    2012-08-01

    Skeletal muscle mass declines with age (i.e., sarcopenia) resulting in muscle weakness and functional limitations. Sarcopenia has been associated with physiological changes in muscle morphology, protein and hormonal kinetics, insulin resistance, inflammation, and oxidative stress. The purpose of this review is to highlight how exercise and nutritional intervention strategies may benefit aging muscle. It is well known that resistance exercise training increases muscle strength and size and evidence also suggests that resistance training can increase mitochondrial content and decrease oxidative stress in older adults. Recent findings suggest that fast-velocity resistance exercise may be an effective intervention for older adults to enhance muscle power and functional capacity. Aerobic exercise training may also benefit aging skeletal muscle by enhancing mitochondrial bioenergetics, improving insulin sensitivity, and/or decreasing oxidative stress. In addition to exercise, creatine monohydrate, milk-based proteins, and essential fatty acids all have biological effects which could enhance some of the physiological adaptations from exercise training in older adults. Additional research is needed to determine whether skeletal muscle adaptations to increased activity in older adults are further enhanced with effective nutritional interventions and whether this is due to enhanced muscle protein synthesis, improved mitochondrial function, and/or a reduced inflammatory response. PMID:22527891

  15. No clinical or neurophysiological evidence of botulinum toxin diffusion to non-injected muscles in patients with hemifacial spasm.

    PubMed

    Lorenzano, C; Bagnato, S; Gilio, F; Fabbrini, G; Berardelli, A

    2006-04-01

    Botulinum toxin injected into a muscle may diffuse to nearby muscles thus producing unwanted effects. In patients with hemifacial spasm, we evaluated clinically and neurophysiologically, whether botulinum toxin type A (BoNT-A) diffuses from the injection site (orbicularis oculi) to untreated muscles (orbicularis oris from the affected side and orbicularis oculi and oris from the unaffected side). We studied 38 patients with idiopathic hemifacial spasm. Botulinum toxin was injected into the affected orbicularis oculi muscle alone (at 3 standardized sites) at a clinically effective dose. Patients were studied before (T0) and 3-4 weeks after treatment (T1). We evaluated the clinical effects of botulinum toxin and muscle strength in the affected and unaffected muscles. We also assessed the peak-to-peak amplitude compound muscle action potential (CMAP) recorded from the orbicularis oculi and orbicularis oris muscles on both sides after supramaximal electrical stimulation of the facial nerve at the stylomastoid foramen. In all patients, botulinum toxin treatment reduced muscle spasms in the injected orbicularis oculi muscle and induced no muscle weakness in the other facial muscles. The CMAP amplitude significantly decreased in the injected orbicularis oculi muscle, but remained unchanged in the other facial muscles (orbicularis oris muscle on the affected side and contra-lateral unaffected muscles). In conclusion, in patients with hemifacial spasm, botulinum toxin, at a clinically effective dose, induces no clinical signs of diffusion and does not reduce the CMAP size in the nearby untreated orbicularis oris or contralateral facial muscles.

  16. Resolution of pronounced painless weakness arising from radiculopathy and disk extrusion.

    PubMed

    Lipetz, Jason S; Misra, Neelam; Silber, Jeff S

    2005-07-01

    In this retrospective, consecutive case series, we report the nonsurgical and rehabilitation outcomes of consecutive patients who presented with pronounced painless weakness arising from disk extrusion. Seven consecutive patients who chose physiatric care were followed clinically, and strength return was monitored. Each presented with predominantly painless radiculopathy, functionally significant strength loss, and radiographic evidence of disk extrusion or sequestration. Each patient participated in a targeted strengthening program, and in some cases, transforaminal injection therapy was employed. Each patient demonstrated an eventual full functional recovery. In most cases, electrodiagnostic studies were performed and included a needle examination of the affected limb and compound muscle action potentials from the most clinically relevant and weakened limb muscle. The electrodiagnostic findings and, in particular, the quantitative compound muscle action potential data seemed to correlate with the timing of motor recovery. Patients with predominantly painless and significant weakness arising from disk extrusion can demonstrate successful rehabilitation outcomes. Despite a relative absence of pain, such patients can present with a more rapidly reversible neurapraxic type of weakness. The more quantitative compound muscle action potential data obtained through electrodiagnostic studies may offer the treating physician an additional means of characterizing the type of neuronal injury at play and the likelihood and timing of strength return. PMID:15973090

  17. Subcellular distribution of potassium in striated muscles

    SciTech Connect

    Edelmann, L.

    1984-01-01

    Microanalytical experiments have been performed to answer the question whether the main cellular cation, K+, follows the water distribution in the striated muscle cell or whether K+ follows the distribution of negative fixed charges (beta- and gamma-carboxyl groups of aspartic and glutamic acid residues). Subcellular localization of K and/or of the K surrogates Rb, Cs, and Tl has been investigated by the following methods: Chemical precipitation of K with tetraphenylborate. Autoradiography of alkali-metals and Tl in air-dried and frozen-hydrated preparations. TEM visualization of electron dense Cs and Tl in sections of freeze-dried and plastic embedded muscle. X-ray microanalysis of air-dried myofibrils and muscle cryosections. The experiments consistently show that K, Rb, Cs, and Tl do not follow the water distribution but are mainly accumulated in the A band, especially in the marginal regions, and at Z lines. The same sites preferentially accumulate Cs or uranyl cations when sections of freeze-dried, embedded muscle are exposed to these electron microscopic stains. It is concluded that the detected uneven distribution of K, Rb, Cs, and Tl in muscle is neither a freeze-drying artifact nor an embedding artifact and may result from a weak ion binding to the beta- and gamma-carboxyl groups of cellular proteins.

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

    PubMed Central

    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

  19. Protecting weak measurements against systematic errors

    NASA Astrophysics Data System (ADS)

    Pang, Shengshi; Alonso, Jose Raul Gonzalez; Brun, Todd A.; Jordan, Andrew N.

    2016-07-01

    In this work, we consider the systematic error of quantum metrology by weak measurements under decoherence. We derive the systematic error of maximum likelihood estimation in general to the first-order approximation of a small deviation in the probability distribution and study the robustness of standard weak measurement and postselected weak measurements against systematic errors. We show that, with a large weak value, the systematic error of a postselected weak measurement when the probe undergoes decoherence can be significantly lower than that of a standard weak measurement. This indicates another advantage of weak-value amplification in improving the performance of parameter estimation. We illustrate the results by an exact numerical simulation of decoherence arising from a bosonic mode and compare it to the first-order analytical result we obtain.

  20. A Universe without Weak Interactions

    SciTech Connect

    Harnik, Roni; Kribs, Graham D.; Perez, Gilad

    2006-04-07

    A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''Weakless Universe'' is matched to our Universe by simultaneously adjusting Standard Model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the Weakless Universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multi-parameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe.

  1. Weak Turbulence in Radiation Belts

    NASA Astrophysics Data System (ADS)

    Ganguli, Gurudas; Crabtree, Chris; Rudakov, Leonid

    2015-11-01

    Weak turbulence plays a significant role in space plasma dynamics. Induced nonlinear scattering dominates the evolution in the low-beta isothermal radiation belt plasmas and affects the propagation characteristics of waves. As whistler waves propagate away from the earth they are scattered in the magnetosphere such that their trajectories are turned earthward where they are reflected back towards the magnetosphere. Repeated scattering and reflection of the whistlers establishes a cavity in which the wave energy can be maintained for a long duration with, on average, a smaller wave-normal angle. Consequently, the cyclotron resonance time for the trapped energetic electrons increases, leading to an enhanced pitch-angle scattering rate. Enhanced pitch-angle scattering lowers the lifetime of the energetic electron population. Also, pitch-angle scattering of the trapped population in the cavity with a loss cone distribution amplifies the whistler waves, which in turn promotes a more rapid precipitation through a positive feedback mechanism. Typical storm-pumped radiation belt parameters and laboratory experiments will be used to elucidate this phenomenon Work supported by NRL Base Funds.

  2. Weak Turbulence in Radiation Belts

    NASA Astrophysics Data System (ADS)

    Ganguli, G.; Crabtree, C. E.; Rudakov, L.

    2015-12-01

    Weak turbulence plays a significant role in space plasma dynamics. Induced nonlinear scattering dominates the evolution in the low-beta isothermal radiation belt plasmas and affects the propagation characteristics of waves. As whistler waves propagate away from the earth they are scattered in the magnetosphere such that their trajectories are turned earthward where they are reflected back towards the magnetosphere. Repeated scattering and reflection of the whistlers establishes a cavity in which the wave energy can be maintained for a long duration with, on average, a smaller wave-normal angle. Consequently, the cyclotron resonance time for the trapped energetic electrons increases, leading to an enhanced pitch-angle scattering rate. Enhanced pitch-angle scattering lowers the lifetime of the energetic electron population. Also, pitch-angle scattering of the trapped population in the cavity with a loss cone distribution amplifies the whistler waves, which in turn promotes a more rapid precipitation through a positive feedback mechanism. Typical storm-pumped radiation belt parameters and laboratory experiments will be used to elucidate this phenomenon.

  3. Muscle-directed gene therapy for phenylketonuria (PKU): Development of transgenic mice with muscle-specific phenylalanine hydroxylase expression

    SciTech Connect

    Harding, C.O.; Messing, A.; Wolff, J.A.

    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.

  4. Reduced force of diaphragm muscle fibers in patients with chronic thromboembolic pulmonary hypertension.

    PubMed

    Manders, Emmy; Bonta, Peter I; Kloek, Jaap J; Symersky, Petr; Bogaard, Harm-Jan; Hooijman, Pleuni E; Jasper, Jeff R; Malik, Fady I; Stienen, Ger J M; Vonk-Noordegraaf, Anton; de Man, Frances S; Ottenheijm, Coen A C

    2016-07-01

    Patients with pulmonary hypertension (PH) suffer from inspiratory muscle weakness. However, the pathophysiology of inspiratory muscle dysfunction in PH is unknown. We hypothesized that weakness of the diaphragm, the main inspiratory muscle, is an important contributor to inspiratory muscle dysfunction in PH patients. Our objective was to combine ex vivo diaphragm muscle fiber contractility measurements with measures of in vivo inspiratory muscle function in chronic thromboembolic pulmonary hypertension (CTEPH) patients. To assess diaphragm muscle contractility, function was studied in vivo by maximum inspiratory pressure (MIP) and ex vivo in diaphragm biopsies of the same CTEPH patients (N = 13) obtained during pulmonary endarterectomy. Patients undergoing elective lung surgery served as controls (N = 15). Muscle fiber cross-sectional area (CSA) was determined in cryosections and contractility in permeabilized muscle fibers. Diaphragm muscle fiber CSA was not significantly different between control and CTEPH patients in both slow-twitch and fast-twitch fibers. Maximal force-generating capacity was significantly lower in slow-twitch muscle fibers of CTEPH patients, whereas no difference was observed in fast-twitch muscle fibers. The maximal force of diaphragm muscle fibers correlated significantly with MIP. The calcium sensitivity of force generation was significantly reduced in fast-twitch muscle fibers of CTEPH patients, resulting in a ∼40% reduction of submaximal force generation. The fast skeletal troponin activator CK-2066260 (5 μM) restored submaximal force generation to levels exceeding those observed in control subjects. In conclusion, diaphragm muscle fiber contractility is hampered in CTEPH patients and contributes to the reduced function of the inspiratory muscles in CTEPH patients. PMID:27190061

  5. Rejuvenation of the muscle stem cell population restores strength to injured aged muscles.

    PubMed

    Cosgrove, Benjamin D; Gilbert, Penney M; Porpiglia, Ermelinda; Mourkioti, Foteini; Lee, Steven P; Corbel, Stephane Y; Llewellyn, Michael E; Delp, Scott L; Blau, Helen M

    2014-03-01

    The elderly often suffer from progressive muscle weakness and regenerative failure. We demonstrate that muscle regeneration is impaired with aging owing in part to a cell-autonomous functional decline in skeletal muscle stem cells (MuSCs). Two-thirds of MuSCs from aged mice are intrinsically defective relative to MuSCs from young mice, with reduced capacity to repair myofibers and repopulate the stem cell reservoir in vivo following transplantation. This deficiency is correlated with a higher incidence of cells that express senescence markers and is due to elevated activity of the p38α and p38β mitogen-activated kinase pathway. We show that these limitations cannot be overcome by transplantation into the microenvironment of young recipient muscles. In contrast, subjecting the MuSC population from aged mice to transient inhibition of p38α and p38β in conjunction with culture on soft hydrogel substrates rapidly expands the residual functional MuSC population from aged mice, rejuvenating its potential for regeneration and serial transplantation as well as strengthening of damaged muscles of aged mice. These findings reveal a synergy between biophysical and biochemical cues that provides a paradigm for a localized autologous muscle stem cell therapy for the elderly.

  6. Muscle Size Not Density Predicts Variance in Muscle Strength and Neuromuscular Performance in Healthy Adult Men and Women.

    PubMed

    Weeks, Benjamin K; Gerrits, Tom A J; Horan, Sean A; Beck, Belinda R

    2016-06-01

    Weeks, BK, Gerrits, TAJ, Horan, SA, and Beck, BR. Muscle size not density predicts variance in muscle strength and neuromuscular performance in healthy adult men and women. J Strength Cond Res 30(6): 1577-1584, 2016-The purpose of this study was to determine the relationships between peripheral quantitative computed tomography (pQCT)-derived measures of muscle area and density and markers of muscle strength and performance in men and women. Fifty-two apparently healthy adults (26 men, 26 women; age 33.8 ± 12.0 years) volunteered to participate. Dual-energy x-ray absorptiometry (XR-800; Norland Medical Systems, Inc., Trumbull, CT, USA) was used to determine whole body and regional lean and fat tissue mass, whereas pQCT (XCT-3000; Stratec, Pforzheim, Germany) was used to determine muscle cross-sectional area (MCSA) and muscle density of the leg, thigh, and forearm. Ankle plantar flexor and knee extensor strengths were examined using isokinetic dynamometry, and grip strength was examined with dynamometry. Impulse generated during a maximal vertical jump was used as an index of neuromuscular performance. Thigh, forearm, and leg MCSA strongly predicted variance in knee extensor (R = 0.77, p < 0.001) and grip strength (R = 0.77, p < 0.001) and weakly predicted variance in ankle plantar flexor strength (R = 0.20, p < 0.001), respectively, whereas muscle density was only a weak predictor of variance in knee extensor strength (R = 0.18, p < 0.001). Thigh and leg MCSA accounted for 79 and 69% of the variance in impulse generated from a maximal vertical jump (p < 0.001), whereas thigh muscle density predicted only 18% of the variance (p < 0.002). In conclusion, we found that pQCT-derived muscle area is more strongly related to strength and neuromuscular performance than muscle density in adult men and women.

  7. The management of weakness caused by lumbar and lumbosacral nerve root compression.

    PubMed

    Sharma, H; Lee, S W J; Cole, A A

    2012-11-01

    Spinal stenosis and disc herniation are the two most frequent causes of lumbosacral nerve root compression. This can result in muscle weakness and present with or without pain. The difficulty when managing patients with these conditions is knowing when surgery is better than non-operative treatment: the evidence is controversial. Younger patients with a lesser degree of weakness for a shorter period of time have been shown to respond better to surgical treatment than older patients with greater weakness for longer. However, they also constitute a group that fares better without surgery. The main indication for surgical treatment in the management of patients with lumbosacral nerve root compression should be pain rather than weakness.

  8. Pixelation Effects in Weak Lensing

    NASA Astrophysics Data System (ADS)

    High, F. William; Rhodes, Jason; Massey, Richard; Ellis, Richard

    2007-11-01

    Weak gravitational lensing can be used to investigate both dark matter and dark energy but requires accurate measurements of the shapes of faint, distant galaxies. Such measurements are hindered by the finite resolution and pixel scale of digital cameras. We investigate the optimum choice of pixel scale for a space-based mission, using the engineering model and survey strategy of the proposed Supernova Acceleration Probe as a baseline. We do this by simulating realistic astronomical images containing a known input shear signal and then attempting to recover the signal using the Rhodes, Refregier, & Groth algorithm. We find that the quality of shear measurement is always improved by smaller pixels. However, in practice, telescopes are usually limited to a finite number of pixels and operational life span, so the total area of a survey increases with pixel size. We therefore fix the survey lifetime and the number of pixels in the focal plane while varying the pixel scale, thereby effectively varying the survey size. In a pure trade-off for image resolution versus survey area, we find that measurements of the matter power spectrum would have minimum statistical error with a pixel scale of 0.09" for a 0.14" FWHM point-spread function (PSF). The pixel scale could be increased to ~0.16" if images dithered by exactly half-pixel offsets were always available. Some of our results do depend on our adopted shape measurement method and should be regarded as an upper limit: future pipelines may require smaller pixels to overcome systematic floors not yet accessible, and, in certain circumstances, measuring the shape of the PSF might be more difficult than those of galaxies. However, the relative trends in our analysis are robust, especially those of the surface density of resolved galaxies. Our approach thus provides a snapshot of potential in available technology, and a practical counterpart to analytic studies of pixelation, which necessarily assume an idealized shape

  9. Weak {}^* convergence of operator means

    NASA Astrophysics Data System (ADS)

    Romanov, Alexandr V.

    2011-12-01

    For a linear operator U with \\Vert U^n\\Vert \\le \\operatorname{const} on a Banach space X we discuss conditions for the convergence of ergodic operator nets T_\\alpha corresponding to the adjoint operator U^* of U in the {W^*O}-topology of the space \\operatorname{End} X^*. The accumulation points of all possible nets of this kind form a compact convex set L in \\operatorname{End} X^*, which is the kernel of the operator semigroup G=\\overline{\\operatorname{co}}\\,\\Gamma_0, where \\Gamma_0=\\{U_n^*, n \\ge 0\\}. It is proved that all ergodic nets T_\\alpha weakly {}^* converge if and only if the kernel L consists of a single element. In the case of X=C(\\Omega) and the shift operator U generated by a continuous transformation \\varphi of a metrizable compactum \\Omega we trace the relationships among the ergodic properties of U, the structure of the operator semigroups L, G and \\Gamma=\\overline{\\Gamma}_0, and the dynamical characteristics of the semi-cascade (\\varphi,\\Omega). In particular, if \\operatorname{card}L=1, then a) for any \\omega \\in\\Omega the closure of the trajectory \\{\\varphi^n\\omega, n \\ge 0\\} contains precisely one minimal set m, and b) the restriction (\\varphi,m) is strictly ergodic. Condition a) implies the {W^*O}-convergence of any ergodic sequence of operators T_n \\in \\operatorname{End} X^* under the additional assumption that the kernel of the enveloping semigroup E(\\varphi,\\Omega) contains elements obtained from the `basis' family of transformations \\{\\varphi^n, n \\ge 0\\} of the compact set \\Omega by using some transfinite sequence of sequential passages to the limit.

  10. Muscle development and obesity

    PubMed Central

    2008-01-01

    The formation of skeletal muscle from the epithelial somites involves a series of events triggered by temporally and spatially discrete signals resulting in the generation of muscle fibers which vary in their contractile and metabolic nature. The fiber type composition of muscles varies between individuals and it has now been found that there are differences in fiber type proportions between lean and obese animals and humans. Amongst the possible causes of obesity, it has been suggested that inappropriate prenatal environments may ‘program’ the fetus and may lead to increased risks for disease in adult life. The characteristics of muscle are both heritable and plastic, giving the tissue some ability to adapt to signals and stimuli both pre and postnatally. Given that muscle is a site of fatty acid oxidation and carbohydrate metabolism and that its development can be changed by prenatal events, it is interesting to examine the possible relationship between muscle development and the risk of obesity. PMID:19279728

  11. Muscle Changes in Aging

    PubMed Central

    Siparsky, Patrick N.; Kirkendall, Donald T.; Garrett, William E.

    2014-01-01

    Muscle physiology in the aging athlete is complex. Sarcopenia, the age-related decrease in lean muscle mass, can alter activity level and affect quality of life. This review addresses the microscopic and macroscopic changes in muscle with age, recognizes contributing factors including nutrition and changes in hormone levels, and identifies potential pharmacologic agents in clinical trial that may aid in the battle of this complex, costly, and disabling problem. Level of Evidence: Level 5. PMID:24427440

  12. An artificial muscle computer

    NASA Astrophysics Data System (ADS)

    Marc O'Brien, Benjamin; Alexander Anderson, Iain

    2013-03-01

    We have built an artificial muscle computer based on Wolfram's "2, 3" Turing machine architecture, the simplest known universal Turing machine. Our computer uses artificial muscles for its instruction set, output buffers, and memory write and addressing mechanisms. The computer is very slow and large (0.15 Hz, ˜1 m3); however by using only 13 artificial muscle relays, it is capable of solving any computable problem given sufficient memory, time, and reliability. The development of this computer shows that artificial muscles can think—paving the way for soft robots with reflexes like those seen in nature.

  13. MUSCLE INJURIES IN ATHLETES

    PubMed Central

    Barroso, Guilherme Campos; Thiele, Edilson Schwansee

    2015-01-01

    This article had the aim of demonstrating the physiology, diagnosis and treatment of muscle injuries, focusing on athletes and their demands and expectations. Muscle injuries are among the most common complaints in orthopedic practice, occurring both among athletes and among non-athletes. These injuries present a challenge for specialists, due to the slow recovery, during which time athletes are unable to take part in training and competitions, and due to frequent sequelae and recurrences of the injuries. Most muscle injuries (between 10% and 55% of all injuries) occur during sports activities. The muscles most commonly affected are the ischiotibial, quadriceps and gastrocnemius. These muscles go across two joints and are more subject to acceleration and deceleration forces. The treatment for muscle injuries varies from conservative treatment to surgery. New procedures are being used, like the hyperbaric chamber and the use of growth factors. However, there is still a high rate of injury recurrence. Muscle injury continues to be a topic of much controversy. New treatments are being researched and developed, but prevention through muscle strengthening, stretching exercises and muscle balance continues to be the best “treatment”. PMID:27027021

  14. Instrumental systematics and weak gravitational lensing

    NASA Astrophysics Data System (ADS)

    Mandelbaum, R.

    2015-05-01

    We present a pedagogical review of the weak gravitational lensing measurement process and its connection to major scientific questions such as dark matter and dark energy. Then we describe common ways of parametrizing systematic errors and understanding how they affect weak lensing measurements. Finally, we discuss several instrumental systematics and how they fit into this context, and conclude with some future perspective on how progress can be made in understanding the impact of instrumental systematics on weak lensing measurements.

  15. Spin effects in the weak interaction

    SciTech Connect

    Freedman, S.J. Chicago Univ., IL . Dept. of Physics Chicago Univ., IL . Enrico Fermi Inst.)

    1990-01-01

    Modern experiments investigating the beta decay of the neutron and light nuclei are still providing important constraints on the theory of the weak interaction. Beta decay experiments are yielding more precise values for allowed and induced weak coupling constants and putting constraints on possible extensions to the standard electroweak model. Here we emphasize the implications of recent experiments to pin down the strengths of the weak vector and axial vector couplings of the nucleon.

  16. Hypophosphatemia promotes lower rates of muscle ATP synthesis

    PubMed Central

    Pesta, Dominik H.; Tsirigotis, Dimitrios N.; Befroy, Douglas E.; Caballero, Daniel; Jurczak, Michael J.; Rahimi, Yasmeen; Cline, Gary W.; Dufour, Sylvie; Birkenfeld, Andreas L.; Rothman, Douglas L.; Carpenter, Thomas O.; Insogna, Karl; Petersen, Kitt Falk; Bergwitz, Clemens; Shulman, Gerald I.

    2016-01-01

    Hypophosphatemia can lead to muscle weakness and respiratory and heart failure, but the mechanism is unknown. To address this question, we noninvasively assessed rates of muscle ATP synthesis in hypophosphatemic mice by using in vivo saturation transfer [31P]-magnetic resonance spectroscopy. By using this approach, we found that basal and insulin-stimulated rates of muscle ATP synthetic flux (VATP) and plasma inorganic phosphate (Pi) were reduced by 50% in mice with diet-induced hypophosphatemia as well as in sodium-dependent Pi transporter solute carrier family 34, member 1 (NaPi2a)-knockout (NaPi2a−/−) mice compared with their wild-type littermate controls. Rates of VATP normalized in both hypophosphatemic groups after restoring plasma Pi concentrations. Furthermore, VATP was directly related to cellular and mitochondrial Pi uptake in L6 and RC13 rodent myocytes and isolated muscle mitochondria. Similar findings were observed in a patient with chronic hypophosphatemia as a result of a mutation in SLC34A3 who had a 50% reduction in both serum Pi content and muscle VATP. After oral Pi repletion and normalization of serum Pi levels, muscle VATP completely normalized in the patient. Taken together, these data support the hypothesis that decreased muscle ATP synthesis, in part, may be caused by low blood Pi concentrations, which may explain some aspects of muscle weakness observed in patients with hypophosphatemia.—Pesta, D. H., Tsirigotis, D. N., Befroy, D. E., Caballero, D., Jurczak, M. J., Rahimi, Y., Cline, G. W., Dufour, S., Birkenfeld, A. L., Rothman, D. L., Carpenter, T. O., Insogna, K., Petersen, K. F., Bergwitz, C., Shulman, G. I. Hypophosphatemia promotes lower rates of muscle ATP synthesis. PMID:27338702

  17. Multivariable Static Ankle Mechanical Impedance With Active Muscles.

    PubMed

    Lee, Hyunglae; Ho, Patrick; Rastgaar, Mohammad; Krebs, Hermano Igo; Hogan, Neville

    2014-01-01

    This paper reports quantification of multivariable static ankle mechanical impedance when muscles were active. Repetitive measurements using a highly backdrivable therapeutic robot combined with robust function approximation methods enabled reliable characterization of the nonlinear torque-angle relation at the ankle in two coupled degrees of freedom simultaneously, a combination of dorsiflexion-plantarflexion and inversion-eversion, and how it varied with muscle activation. Measurements on 10 young healthy seated subjects quantified the behavior of the human ankle when muscles were active at 10% of maximum voluntary contraction. Stiffness, a linear approximation to static ankle mechanical impedance, was estimated from the continuous vector field. As with previous measurements when muscles were maximally relaxed, we found that ankle stiffness was highly direction-dependent, being weakest in inversion/eversion. Predominantly activating a single muscle or co-contracting antagonistic muscles significantly increased ankle stiffness in all directions but it increased more in the sagittal plane than in the frontal plane, accentuating the relative weakness of the ankle in the inversion-eversion direction. Remarkably, the observed increase was not consistent with simple superposition of muscle-generated stiffness, which may be due to the contribution of unmonitored deep ankle muscles. Implications for the assessment of neuro-mechanical disorders are discussed.

  18. The role of TORC1 in muscle development in Drosophila.

    PubMed

    Hatfield, Isabelle; Harvey, Innocence; Yates, Erika R; Redd, JeAnna R; Reiter, Lawrence T; Bridges, Dave

    2015-01-01

    Myogenesis is an important process during both development and muscle repair. Previous studies suggest that mTORC1 plays a role in the formation of mature muscle from immature muscle precursor cells. Here we show that gene expression for several myogenic transcription factors including Myf5, Myog and Mef2c but not MyoD and myosin heavy chain isoforms decrease when C2C12 cells are treated with rapamycin, supporting a role for mTORC1 pathway during muscle development. To investigate the possibility that mTORC1 can regulate muscle in vivo we ablated the essential dTORC1 subunit Raptor in Drosophila melanogaster and found that muscle-specific knockdown of Raptor causes flies to be too weak to emerge from their pupal cases during eclosion. Using a series of GAL4 drivers we also show that muscle-specific Raptor knockdown also causes shortened lifespan, even when eclosure is unaffected. Together these results highlight an important role for TORC1 in muscle development, integrity and function in both Drosophila and mammalian cells.

  19. CuZnSOD gene deletion targeted to skeletal muscle leads to loss of contractile force but does not cause muscle atrophy in adult mice

    PubMed Central

    Zhang, Yiqiang; Davis, Carol; Sakellariou, George K.; Shi, Yun; Kayani, Anna C.; Pulliam, Daniel; Bhattacharya, Arunabh; Richardson, Arlan; Jackson, Malcolm J.; McArdle, Anne; Brooks, Susan V.; Van Remmen, Holly

    2013-01-01

    We have previously shown that deletion of CuZnSOD in mice (Sod1−/− mice) leads to accelerated loss of muscle mass and contractile force during aging. To dissect the relative roles of skeletal muscle and motor neurons in this process, we used a Cre-Lox targeted approach to establish a skeletal muscle-specific Sod1-knockout (mKO) mouse to determine whether muscle-specific CuZnSOD deletion is sufficient to cause muscle atrophy. Surprisingly, mKO mice maintain muscle masses at or above those of wild-type control mice up to 18 mo of age. In contrast, maximum isometric specific force measured in gastrocnemius muscle is significantly reduced in the mKO mice. We found no detectable increases in global measures of oxidative stress or ROS production, no reduction in mitochondrial ATP production, and no induction of adaptive stress responses in muscle from mKO mice. However, Akt-mTOR signaling is elevated and the number of muscle fibers with centrally located nuclei is increased in skeletal muscle from mKO mice, which suggests elevated regenerative pathways. Our data demonstrate that lack of CuZnSOD restricted to skeletal muscle does not lead to muscle atrophy but does cause muscle weakness in adult mice and suggest loss of CuZnSOD may potentiate muscle regenerative pathways.—Zhang, Y., Davis, C., Sakellariou, G.K., Shi, Y., Kayani, A.C., Pulliam, D., Bhattacharya, A., Richardson, A., Jackson, M.J., McArdle, A., Brooks, S.V., Van Remmen, H. CuZnSOD gene deletion targeted to skeletal muscle leads to loss of contractile force but does not cause muscle atrophy in adult mice. PMID:23729587

  20. Towards the development of a novel experimental shoulder simulator with rotating scapula and individually controlled muscle forces simulating the rotator cuff.

    PubMed

    Baumgartner, Daniel; Tomas, Daniel; Gossweiler, Lukas; Siegl, Walter; Osterhoff, Georg; Heinlein, Bernd

    2014-03-01

    A preclinical analysis of novel implants used in shoulder surgery requires biomechanical testing conditions close to physiology. Existing shoulder experiments may only partially apply multiple cycles to simulate postoperative, repetitive loading tasks. The aim of the present study was therefore the development of an experimental shoulder simulator with rotating scapula able to perform multiple humeral movement cycles by simulating individual muscles attached to the rotator cuff. A free-hanging, metallic humerus pivoted in a polyethylene glenoid is activated by tension forces of linear electroactuators to simulate muscles of the deltoideus (DELT), supraspinatus (SSP), infraspinatus/teres minor and subscapularis. The abductors DELT and SSP apply forces with a ratio of 3:1 up to an abduction angle of 85°. The rotating scapular part driven by a rotative electro actuator provides one-third to the overall arm abduction. Resulting joint forces and moments are measured by a 6-axis load cell. A linear increase in the DELT and SSP motors is shown up to a maximum of 150 and 50 N for the DELT and SSP, respectively. The force vector in the glenoid resulted in 253 N at the maximum abduction. The present investigation shows the contribution of individual muscle forces attached to the moving humerus to perform active abduction in order to reproducibly test shoulder implants.

  1. Ischemia causes muscle fatigue

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    The purpose of this investigation was to determine whether ischemia, which reduces oxygenation in the extensor carpi radialis (ECR) muscle, causes a reduction in muscle force production. In eight subjects, muscle oxygenation (TO2) of the right ECR was measured noninvasively and continuously using near infrared spectroscopy (NIRS) while muscle twitch force was elicited by transcutaneous electrical stimulation (1 Hz, 0.1 ms). Baseline measurements of blood volume, muscle oxygenation and twitch force were recorded continuously, then a tourniquet on the upper arm was inflated to one of five different pressure levels: 20, 40, 60 mm Hg (randomized order) and diastolic (69 +/- 9.8 mm Hg) and systolic (106 +/- 12.8 mm Hg) blood pressures. Each pressure level was maintained for 3-5 min, and was followed by a recovery period sufficient to allow measurements to return to baseline. For each respective tourniquet pressure level, mean TO2 decreased from resting baseline (100% TO2) to 99 +/- 1.2% (SEM), 96 +/- 1.9%, 93 +/- 2.8%, 90 +/- 2.5%, and 86 +/- 2.7%, and mean twitch force decreased from resting baseline (100% force) to 99 +/- 0.7% (SEM), 96 +/- 2.7%, 93 +/- 3.1%, 88 +/- 3.2%, and 86 +/- 2.6%. Muscle oxygenation and twitch force at 60 mm Hg tourniquet compression and above were significantly lower (P < 0.05) than baseline value. Reduced twitch force was correlated in a dose-dependent manner with reduced muscle oxygenation (r = 0.78, P < 0.001). Although the correlation does not prove causation, the results indicate that ischemia leading to a 7% or greater reduction in muscle oxygenation causes decreased muscle force production in the forearm extensor muscle. Thus, ischemia associated with a modest decline in TO2 causes muscle fatigue.

  2. Accurate and representative decoding of the neural drive to muscles in humans with multi-channel intramuscular thin-film electrodes.

    PubMed

    Muceli, Silvia; Poppendieck, Wigand; Negro, Francesco; Yoshida, Ken; Hoffmann, Klaus P; Butler, Jane E; Gandevia, Simon C; Farina, Dario

    2015-09-01

    Intramuscular electrodes developed over the past 80 years can record the concurrent activity of only a few motor units active during a muscle contraction. We designed, produced and tested a novel multi-channel intramuscular wire electrode that allows in vivo concurrent recordings of a substantially greater number of motor units than with conventional methods. The electrode has been extensively tested in deep and superficial human muscles. The performed tests indicate the applicability of the proposed technology in a variety of conditions. The electrode represents an important novel technology that opens new avenues in the study of the neural control of muscles in humans. We describe the design, fabrication and testing of a novel multi-channel thin-film electrode for detection of the output of motoneurones in vivo and in humans, through muscle signals. The structure includes a linear array of 16 detection sites that can sample intramuscular electromyographic activity from the entire muscle cross-section. The structure was tested in two superficial muscles (the abductor digiti minimi (ADM) and the tibialis anterior (TA)) and a deep muscle (the genioglossus (GG)) during contractions at various forces. Moreover, surface electromyogram (EMG) signals were concurrently detected from the TA muscle with a grid of 64 electrodes. Surface and intramuscular signals were decomposed into the constituent motor unit (MU) action potential trains. With the intramuscular electrode, up to 31 MUs were identified from the ADM muscle during an isometric contraction at 15% of the maximal force (MVC) and 50 MUs were identified for a 30% MVC contraction of TA. The new electrode detects different sources from a surface EMG system, as only one MU spike train was found to be common in the decomposition of the intramuscular and surface signals acquired from the TA. The system also allowed access to the GG muscle, which cannot be analysed with surface EMG, with successful identification of MU

  3. Accurate and representative decoding of the neural drive to muscles in humans with multi-channel intramuscular thin-film electrodes.

    PubMed

    Muceli, Silvia; Poppendieck, Wigand; Negro, Francesco; Yoshida, Ken; Hoffmann, Klaus P; Butler, Jane E; Gandevia, Simon C; Farina, Dario

    2015-09-01

    Intramuscular electrodes developed over the past 80 years can record the concurrent activity of only a few motor units active during a muscle contraction. We designed, produced and tested a novel multi-channel intramuscular wire electrode that allows in vivo concurrent recordings of a substantially greater number of motor units than with conventional methods. The electrode has been extensively tested in deep and superficial human muscles. The performed tests indicate the applicability of the proposed technology in a variety of conditions. The electrode represents an important novel technology that opens new avenues in the study of the neural control of muscles in humans. We describe the design, fabrication and testing of a novel multi-channel thin-film electrode for detection of the output of motoneurones in vivo and in humans, through muscle signals. The structure includes a linear array of 16 detection sites that can sample intramuscular electromyographic activity from the entire muscle cross-section. The structure was tested in two superficial muscles (the abductor digiti minimi (ADM) and the tibialis anterior (TA)) and a deep muscle (the genioglossus (GG)) during contractions at various forces. Moreover, surface electromyogram (EMG) signals were concurrently detected from the TA muscle with a grid of 64 electrodes. Surface and intramuscular signals were decomposed into the constituent motor unit (MU) action potential trains. With the intramuscular electrode, up to 31 MUs were identified from the ADM muscle during an isometric contraction at 15% of the maximal force (MVC) and 50 MUs were identified for a 30% MVC contraction of TA. The new electrode detects different sources from a surface EMG system, as only one MU spike train was found to be common in the decomposition of the intramuscular and surface signals acquired from the TA. The system also allowed access to the GG muscle, which cannot be analysed with surface EMG, with successful identification of MU

  4. Accurate and representative decoding of the neural drive to muscles in humans with multi-channel intramuscular thin-film electrodes

    PubMed Central

    Muceli, Silvia; Poppendieck, Wigand; Negro, Francesco; Yoshida, Ken; Hoffmann, Klaus P; Butler, Jane E; Gandevia, Simon C; Farina, Dario

    2015-01-01

    Abstract We describe the design, fabrication and testing of a novel multi-channel thin-film electrode for detection of the output of motoneurones in vivo and in humans, through muscle signals. The structure includes a linear array of 16 detection sites that can sample intramuscular electromyographic activity from the entire muscle cross-section. The structure was tested in two superficial muscles (the abductor digiti minimi (ADM) and the tibialis anterior (TA)) and a deep muscle (the genioglossus (GG)) during contractions at various forces. Moreover, surface electromyogram (EMG) signals were concurrently detected from the TA muscle with a grid of 64 electrodes. Surface and intramuscular signals were decomposed into the constituent motor unit (MU) action potential trains. With the intramuscular electrode, up to 31 MUs were identified from the ADM muscle during an isometric contraction at 15% of the maximal force (MVC) and 50 MUs were identified for a 30% MVC contraction of TA. The new electrode detects different sources from a surface EMG system, as only one MU spike train was found to be common in the decomposition of the intramuscular and surface signals acquired from the TA. The system also allowed access to the GG muscle, which cannot be analysed with surface EMG, with successful identification of MU activity. With respect to classic detection systems, the presented thin-film structure enables recording from large populations of active MUs of deep and superficial muscles and thus can provide a faithful representation of the neural drive sent to a muscle. Key points Intramuscular electrodes developed over the past 80 years can record the concurrent activity of only a few motor units active during a muscle contraction. We designed, produced and tested a novel multi-channel intramuscular wire electrode that allows in vivo concurrent recordings of a substantially greater number of motor units than with conventional methods. The electrode has been extensively tested

  5. [A case of distal myopathy with rimmed vacuole formation, progresses into proximal-dominant muscle involvement].

    PubMed

    Ishikawa, K; Ohkoshi, N; Arasaki, K; Mizusawa, H; Kanazawa, I

    1992-09-01

    A case of 55-year-old male with distal myopathy with rimmed vacuole formation is reported. He first noticed dragging of his legs at the age of forty-three. Two years later, he was evaluated to have muscle wasting and weakness in lower legs. In another ten years, he became unable to stand or walk unaided. On physical examination, proximal limb muscles were more severely affected than distal limb muscles. Notably, muscle strength of the quadriceps femoris muscles were weak (MRC Scale 3/5), compared to hamstrings, tibialis anterior muscle and gastrocnemius muscle (4/5). Serum creatine kinase, electromyography, nerve conduction velocities were all compatible with this diagnosis. A computed tomography of the musculoskeletal system was consistent with physical findings. Muscle biopsy revealed many fibers with typical rimmed vacuoles (approximately 6% of fibers). Additionally, small amount of ragged-red fibers (0.5%) was noted. Histochemical reaction showed a focal deficiency of cytochrome c oxidase. This case suggests that during the longstanding course of the illness, proximal limb muscles may be more severely affected, and quadriceps femoris muscle may be predominantly involved.

  6. Slow myosin in developing rat skeletal muscle

    PubMed Central

    1987-01-01

    Through S1 nuclease mapping using a specific cDNA probe, we demonstrate that the slow myosin heavy-chain (MHC) gene, characteristic of adult soleus, is expressed in bulk hind limb muscle obtained from the 18-d rat fetus. We support these results by use of a monoclonal antibody (mAb) which is highly specific to the adult slow MHC. Immunoblots of MHC peptide maps show the same peptides, uniquely recognized by this antibody in adult soleus, are also identified in 18-d fetal limb muscle. Thus synthesis of slow myosin is an early event in skeletal myogenesis and is expressed concurrently with embryonic myosin. By immunofluorescence we demonstrate that in the 16-d fetus all primary myotubes in future fast and future slow muscles homogeneously express slow as well as embryonic myosin. Fiber heterogeneity arises owing to a developmentally regulated inhibition of slow MHC accumulation as muscles are progressively assembled from successive orders of cells. Assembly involves addition of new, superficial areas of the anterior tibial muscle (AT) and extensor digitorum longus muscle (EDL) in which primary cells initially stain weakly or are unstained with the slow mAb. In the developing AT and EDL, expression of slow myosin is unstable and is progressively restricted as these muscles specialize more and more towards the fast phenotype. Slow fibers persisting in deep portions of the adult EDL and AT are interpreted as vestiges of the original muscle primordium. A comparable inhibition of slow MHC accumulation occurs in the developing soleus but involves secondary, not primary, cells. Our results show that the fate of secondary cells is flexible and is spatially determined. By RIA we show that the relative proportions of slow MHC are fivefold greater in the soleus than in the EDL or AT at birth. After neonatal denervation, concentrations of slow MHC in the soleus rapidly decline, and we hypothesize that, in this muscle, the nerve protects and amplifies initial programs of slow MHC

  7. Structure of Skeletal Muscle

    MedlinePlus

    ... Cells, Tissues, & Membranes Cell Structure & Function Cell Structure Cell Function Body Tissues Epithelial Tissue Connective Tissue Muscle Tissue ... nerves. This is directly related to the primary function of skeletal muscle, ... an impulse from a nerve cell. Generally, an artery and at least one vein ...

  8. SMOOTH MUSCLE STEM CELLS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vascular smooth muscle cells (SMCs) originate from multiple types of progenitor cells. In the embryo, the most well-studied SMC progenitor is the cardiac neural crest stem cell. Smooth muscle differentiation in the neural crest lineage is controlled by a combination of cell intrinsic factors, includ...

  9. Temporalis muscle hypertrophy and reduced skull eccentricity in Duchenne muscular dystrophy.

    PubMed

    Straathof, C S M; Doorenweerd, N; Wokke, B H A; Dumas, E M; van den Bergen, J C; van Buchem, M A; Hendriksen, J G M; Verschuuren, J J G M; Kan, H E

    2014-10-01

    Muscle hypertrophy and muscle weakness are well known in Duchenne muscular dystrophy. Decreased muscle force can have secondary effects on skeletal growth and development such as facial and dental morphology changes. In this study, we quantified temporal muscle thickness, circumference, and eccentricity of the skull and the head on T1-weighted magnetic resonance imaging (MRI) scans of the head of 15 Duchenne muscular dystrophy patients and 15 controls. Average temporal muscle thickness was significantly increased in patients (12.9 ± 5.2 mm) compared to controls (6.8 ± 1.4 mm) (P < .0001), whereas the shape of the skull was significantly rounder compared to controls. Temporal muscle thickness and skull eccentricity were significantly negatively correlated in patients, and positively in controls. Hypertrophy of the temporal muscles and changes in skull eccentricity appear to occur early in the course of Duchenne muscular dystrophy. Further studies in younger patients are needed to confirm a causal relationship.

  10. The effects of lower extremity muscle activation and passive range of motion on single leg squat performance.

    PubMed

    Mauntel, Timothy C; Begalle, Rebecca L; Cram, Tyler R; Frank, Barnett S; Hirth, Christopher J; Blackburn, Troy; Padua, Darin A

    2013-07-01

    Knee valgus is a potential risk factor for lower extremity (LE) injuries. Clinical movement screenings and passive range of motion (PROM) measurements may help identify neuromuscular patterns, which contribute to knee valgus. The purpose of this study was to compare LE muscle activation and PROM between subjects who display visual medial knee displacement (MKD) during a single leg squat (SLS) and those who do not. We hypothesized that muscular activation and PROM would differ between the groups. Forty physically active adults (20 controls, 20 MKDs) participated in this study. Subjects completed 10 LE PROM assessments and performed 5 SLS trials while electromyography (EMG) data were collected from 8 LE muscles. Three separate multivariate analysis of variance were used to identify group differences in EMG data, muscle coactivation, and PROM. Results during the SLS indicated hip coactivation ratios revealed smaller gluteus medius to hip adductor (GMed:Hip Add) (p = 0.028) and gluteus maximus to hip adductor (GMax:Hip Add) coactivation ratios (p = 0.007) compared with the control group. Also, the MKD group displayed significantly less passive ankle dorsiflexion with the knee extended (p = 0.047) and flexed (p = 0.034), and greater talar glide motion (p = 0.012). The findings of this study indicate that MKD during a SLS seems to be influenced by decreased coactivation of the gluteal to the hip adductor muscles and restricted dorsiflexion. Therefore, conditioning, rehabilitation, and injury prevention programs should focus on decreasing hip adductor activity, increasing hip abductor and external rotator activity, and increasing ankle dorsiflexion in hopes to decrease the incidence of these injuries. PMID:23096063

  11. Types of muscle tissue (image)

    MedlinePlus

    The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac muscle cells are located in ... heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow ...

  12. Research opportunities in muscle atrophy

    NASA Technical Reports Server (NTRS)

    Herbison, G. J.; Talbot, J. M.

    1984-01-01

    A trophy of skeletal muscle; muscle a trophy associated with manned space flight; the nature, causes, and mechanisms of muscle atrophy associated with space flight, selected physiological factors, biochemical aspects, and countermeasures are addressed.

  13. Onion artificial muscles

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Chun; Shih, Wen-Pin; Chang, Pei-Zen; Lai, Hsi-Mei; Chang, Shing-Yun; Huang, Pin-Chun; Jeng, Huai-An

    2015-05-01

    Artificial muscles are soft actuators with the capability of either bending or contraction/elongation subjected to external stimulation. However, there are currently no artificial muscles that can accomplish these actions simultaneously. We found that the single layered, latticed microstructure of onion epidermal cells after acid treatment became elastic and could simultaneously stretch and bend when an electric field was applied. By modulating the magnitude of the voltage, the artificial muscle made of onion epidermal cells would deflect in opposing directions while either contracting or elongating. At voltages of 0-50 V, the artificial muscle elongated and had a maximum deflection of -30 μm; at voltages of 50-1000 V, the artificial muscle contracted and deflected 1.0 mm. The maximum force response is 20 μN at 1000 V.

  14. Weak rigidity in the PPN formalism

    SciTech Connect

    del Olmo, V.; Olivert, J.

    1987-04-01

    The influence of the concept of weakly rigid almost-thermodynamic material schemes on the classical deformations is analyzed. The methods of the PPN approximation are considered. In this formalism, the equations that characterize the weak rigidity are expressed. As a consequence of that, an increase of two orders of magnitude in the strain rate tensor is obtained.

  15. On modeling weak sinks in MODPATH

    USGS Publications Warehouse

    Abrams, Daniel B.; Haitjema, Henk; Kauffman, Leon J.

    2012-01-01

    Regional groundwater flow systems often contain both strong sinks and weak sinks. A strong sink extracts water from the entire aquifer depth, while a weak sink lets some water pass underneath or over the actual sink. The numerical groundwater flow model MODFLOW may allow a sink cell to act as a strong or weak sink, hence extracting all water that enters the cell or allowing some of that water to pass. A physical strong sink can be modeled by either a strong sink cell or a weak sink cell, with the latter generally occurring in low resolution models. Likewise, a physical weak sink may also be represented by either type of sink cell. The representation of weak sinks in the particle tracing code MODPATH is more equivocal than in MODFLOW. With the appropriate parameterization of MODPATH, particle traces and their associated travel times to weak sink streams can be modeled with adequate accuracy, even in single layer models. Weak sink well cells, on the other hand, require special measures as proposed in the literature to generate correct particle traces and individual travel times and hence capture zones. We found that the transit time distributions for well water generally do not require special measures provided aquifer properties are locally homogeneous and the well draws water from the entire aquifer depth, an important observation for determining the response of a well to non-point contaminant inputs.

  16. Spin Seebeck effect in a weak ferromagnet

    NASA Astrophysics Data System (ADS)

    Arboleda, Juan David; Arnache Olmos, Oscar; Aguirre, Myriam Haydee; Ramos, Rafael; Anadon, Alberto; Ibarra, Manuel Ricardo

    2016-06-01

    We report the observation of room temperature spin Seebeck effect (SSE) in a weak ferromagnetic normal spinel Zinc Ferrite (ZFO). Despite the weak ferromagnetic behavior, the measurements of the SSE in ZFO show a thermoelectric voltage response comparable with the reported values for other ferromagnetic materials. Our results suggest that SSE might possibly originate from the surface magnetization of the ZFO.

  17. Staggering towards a calculation of weak amplitudes

    SciTech Connect

    Sharpe, S.R.

    1988-09-01

    An explanation is given of the methods required to calculate hadronic matrix elements of the weak Hamiltonians using lattice QCD with staggered fermions. New results are presented for the 1-loop perturbative mixing of the weak interaction operators. New numerical techniques designed for staggered fermions are described. A preliminary result for the kaon B parameter is presented. 24 refs., 3 figs.

  18. CP Violation, Neutral Currents, and Weak Equivalence

    DOE R&D Accomplishments Database

    Fitch, V. L.

    1972-03-23

    Within the past few months two excellent summaries of the state of our knowledge of the weak interactions have been presented. Correspondingly, we will not attempt a comprehensive review but instead concentrate this discussion on the status of CP violation, the question of the neutral currents, and the weak equivalence principle.

  19. Advances in weak-values based metrology

    NASA Astrophysics Data System (ADS)

    Jordan, Andrew; Viza, Gerardo; Martínez-Rincón, Julián; Alves, Gabriel; Howell, John; Kwiat, Paul

    2015-03-01

    We theoretically and experimentally describe the relative advantages of implementing weak-values-based metrology versus standard methods. To accomplish this, we measure small optical beam deflections both a weak-values-based technique, and a standard technique. By introducing controlled external modulations of the detector, and transverse beam-jitter, we quantify the mitigation of these sources in the weak values-based experiment versus the standard experiment. In all cases, the weak-values technique performs the same or better than the standard technique by up to two orders of magnitude in precision for our parameters. We further measure the statistical efficiency of the weak-values-based technique. By post-selecting on 1% of the photons, we obtain 99% of the available Fisher information of the beam deflection parameter. We also discuss ways to recycle the discarded events, obtaining much greater precision on a measured parameter.

  20. Atomic homodyne detection of weak atomic transitions.

    PubMed

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  1. Monitoring Murine Skeletal Muscle Function for Muscle Gene Therapy

    PubMed Central

    Hakim, Chady H.; Li, Dejia; Duan, Dongsheng

    2011-01-01

    The primary function of skeletal muscle is to generate force. Muscle force production is compromised in various forms of acquired and/or inherited muscle diseases. An important goal of muscle gene therapy is to recover muscle strength. Genetically engineered mice and spontaneous mouse mutants are readily available for preclinical muscle gene therapy studies. In this chapter, we outlined the methods commonly used for measuring murine skeletal muscle function. These include ex vivo and in situ analysis of the contractile profile of a single intact limb muscle (the extensor digitorium longus for ex vivo assay and the tibialis anterior muscle for in situ assay), grip force analysis, and downhill treadmill exercise. Force measurement in a single muscle is extremely useful for pilot testing of new gene therapy protocols by local gene transfer. Grip force and treadmill assessments offer body-wide evaluation following systemic muscle gene therapy. PMID:21194022

  2. Mechanisms of Muscle Denervation in Aging: Insights from a Mouse Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Park, Kevin H.J

    2015-01-01

    Muscle denervation at the neuromuscular junction (NMJ) is thought to be a contributing factor in age-related muscle weakness. Therefore, understanding the mechanisms that modulate NMJ innervation is a key to developing therapies to combat age-related muscle weakness affecting the elderly. Two mouse models, one lacking the Cu/Zn superoxide dismutase (SOD1) gene and another harboring the transgenic mutant human SOD1 gene, display progressive changes at the NMJ, including muscle endplate fragmentation, nerve terminal sprouting, and denervation. These changes at the NMJ share many of the common features observed in the NMJs of aged mice. In this review, research findings demonstrating the effects of PGC-1α, IGF-1, GDNF, MyoD, myogenin, and miR-206 on NMJ innervation patterns in the G93A SOD1 mice will be highlighted in the context of age-related muscle denervation. PMID:26425392

  3. Evaluation of Respiratory Muscle Strength in Mouth Breathers: Clinical Evidences

    PubMed Central

    Andrade da Cunha, Renata; Andrade da Cunha, Daniele; Assis, Roberta Borba; Bezerra, Luciana Ângelo; Justino da Silva, Hilton

    2013-01-01

    Introduction The child who chronically breathes through the mouth may develop a weakness of the respiratory muscles. Researchers and clinical are seeking for methods of instrumental evaluation to gather complementary data to clinical evaluations. With this in mind, it is important to evaluate breathing muscles in the child with Mouth Breathing. Objective To develop a review to investigate studies that used evaluation methods of respiratory muscle strength in mouth breathers. Data Synthesis  The authors were unanimous in relation to manovacuometry method as a way to evaluate respiratory pressures in Mouth Breathing children. Two of them performed with an analog manovacuometer and the other one, digital. The studies were not evaluated with regard to the method efficacy neither the used instruments. Conclusion There are few studies evaluating respiratory muscle strength in Mouth Breathing people through manovacuometry and the low methodological rigor of the analyzed studies hindered a reliable result to support or refuse the use of this technique. PMID:25992108

  4. Respiratory muscle function and exercise intolerance in heart failure.

    PubMed

    Ribeiro, Jorge P; Chiappa, Gaspar R; Neder, J Alberto; Frankenstein, Lutz

    2009-06-01

    Inspiratory muscle weakness (IMW) is prevalent in patients with chronic heart failure (CHF) caused by left ventricular systolic dysfunction, which contributes to reduced exercise capacity and the presence of dyspnea during daily activities. Inspiratory muscle strength (estimated by maximal inspiratory pressure) has independent prognostic value in CHF. Overall, the results of trials with inspiratory muscle training (IMT) indicate that this intervention improves exercise capacity and quality of life, particularly in patients with CHF and IMW. Some benefit from IMT may be accounted for by the attenuation of the inspiratory muscle metaboreflex. Moreover, IMT results in improved cardiovascular responses to exercise and to those obtained with standard aerobic training. These findings suggest that routine screening for IMW is advisable in patients with CHF, and specific IMT and/or aerobic training are of practical value in the management of these patients. PMID:19486593

  5. Respiratory muscle function and exercise intolerance in heart failure.

    PubMed

    Ribeiro, Jorge P; Chiappa, Gaspar R; Neder, J Alberto; Frankenstein, Lutz

    2009-06-01

    Inspiratory muscle weakness (IMW) is prevalent in patients with chronic heart failure (CHF) caused by left ventricular systolic dysfunction, which contributes to reduced exercise capacity and the presence of dyspnea during daily activities. Inspiratory muscle strength (estimated by maximal inspiratory pressure) has independent prognostic value in CHF. Overall, the results of trials with inspiratory muscle training (IMT) indicate that this intervention improves exercise capacity and quality of life, particularly in patients with CHF and IMW. Some benefit from IMT may be accounted for by the attenuation of the inspiratory muscle metaboreflex. Moreover, IMT results in improved cardiovascular responses to exercise and to those obtained with standard aerobic training. These findings suggest that routine screening for IMW is advisable in patients with CHF, and specific IMT and/or aerobic training are of practical value in the management of these patients.

  6. [Inflammatory myopathy with initial respiratory muscles involvement and rheumatoid arthritis].

    PubMed

    Hunter, Martín; Telias, Irene; Collado, Victoria; Sarano, Judith; Alvarez, Clarisa; Suárez, Juan Pablo

    2014-01-01

    Inflammatory myopathies comprise a heterogeneous group of subacute, chronic and sometimes acute acquired muscle diseases. The most common inflammatory myopathies seen in practice can be separated into four distinct subsets: polymyositis, dermatomyositis, necrotizing autoimmune myositis and inclusion body myositis. These disorders present as proximal and symmetric muscle weakness but rarely respiratory muscles may also be affected. We report the case of a 39 year-old female with inflammatory myopathy with acute respiratory failure due to alveolar hypoventilation secondary to respiratory muscle dysfunction that required mechanical ventilation. The treatment with steroids, methotrexate and intravenous immune globulin was successful as well as the implementation of non-invasive ventilation as an alternative to endotracheal intubation.

  7. Gait propulsion in patients with facioscapulohumeral muscular dystrophy and ankle plantarflexor weakness.

    PubMed

    Rijken, N H M; van Engelen, B G M; de Rooy, J W J; Weerdesteyn, V; Geurts, A C H

    2015-02-01

    Facioscapulohumeral muscular dystrophy is a slowly progressive hereditary disorder resulting in fatty infiltration of eventually most skeletal muscles. Weakness of trunk and leg muscles causes problems with postural balance and gait, and is associated with an increased fall risk. Although drop foot and related tripping are common problems in FSHD, gait impairments are poorly documented. The effect of ankle plantarflexor involvement on gait propulsion has never been addressed. In addition to ankle plantarflexion, gait propulsion is generated through hip flexion and hip extension. Compensatory shifts between these propulsion sources occur when specific muscles are affected. Such a shift may be expected in patients with FSHD since the calves may show early fatty infiltration, whereas iliopsoas and gluteus maximus muscles are often spared for a longer time. In the current study, magnetic resonance imaging was used to assess the percentage of unaffected calf, iliopsoas and gluteus maximus muscles. Joint powers were analyzed in 10 patients with FSHD at comfortable and maximum walking speed to determine the contribution of ankle plantarflexor, hip flexor and hip extensor power to propulsion. Associations between muscle morphology, power generation and gait speed were assessed. Based on multivariate regression analysis, ankle plantarflexor power was the only factor that uniquely contributed to the explained variance of comfortable (R(2)=80%) and maximum (R(2)=86%) walking speed. Although the iliopsoas muscles were largely unaffected, they appeared to be sub-maximally recruited. This submaximal recruitment may be related to poor trunk stability, resulting in a disproportionate effect of calf muscle affliction on gait speed in patients with FSHD. PMID:25687333

  8. Gait propulsion in patients with facioscapulohumeral muscular dystrophy and ankle plantarflexor weakness.

    PubMed

    Rijken, N H M; van Engelen, B G M; de Rooy, J W J; Weerdesteyn, V; Geurts, A C H

    2015-02-01

    Facioscapulohumeral muscular dystrophy is a slowly progressive hereditary disorder resulting in fatty infiltration of eventually most skeletal muscles. Weakness of trunk and leg muscles causes problems with postural balance and gait, and is associated with an increased fall risk. Although drop foot and related tripping are common problems in FSHD, gait impairments are poorly documented. The effect of ankle plantarflexor involvement on gait propulsion has never been addressed. In addition to ankle plantarflexion, gait propulsion is generated through hip flexion and hip extension. Compensatory shifts between these propulsion sources occur when specific muscles are affected. Such a shift may be expected in patients with FSHD since the calves may show early fatty infiltration, whereas iliopsoas and gluteus maximus muscles are often spared for a longer time. In the current study, magnetic resonance imaging was used to assess the percentage of unaffected calf, iliopsoas and gluteus maximus muscles. Joint powers were analyzed in 10 patients with FSHD at comfortable and maximum walking speed to determine the contribution of ankle plantarflexor, hip flexor and hip extensor power to propulsion. Associations between muscle morphology, power generation and gait speed were assessed. Based on multivariate regression analysis, ankle plantarflexor power was the only factor that uniquely contributed to the explained variance of comfortable (R(2)=80%) and maximum (R(2)=86%) walking speed. Although the iliopsoas muscles were largely unaffected, they appeared to be sub-maximally recruited. This submaximal recruitment may be related to poor trunk stability, resulting in a disproportionate effect of calf muscle affliction on gait speed in patients with FSHD.

  9. Muscle wasting in myotonic dystrophies: a model of premature aging

    PubMed Central

    Mateos-Aierdi, Alba Judith; Goicoechea, Maria; Aiastui, Ana; Fernández-Torrón, Roberto; Garcia-Puga, Mikel; Matheu, Ander; López de Munain, Adolfo

    2015-01-01

    Myotonic dystrophy type 1 (DM1 or Steinert’s disease) and type 2 (DM2) are multisystem disorders of genetic origin. Progressive muscular weakness, atrophy and myotonia are the most prominent neuromuscular features of these diseases, while other clinical manifestations such as cardiomyopathy, insulin resistance and cataracts are also common. From a clinical perspective, most DM symptoms are interpreted as a result of an accelerated aging (cataracts, muscular weakness and atrophy, cognitive decline, metabolic dysfunction, etc.), including an increased risk of developing tumors. From this point of view, DM1 could be described as a progeroid syndrome since a notable age-dependent dysfunction of all systems occurs. The underlying molecular disorder in DM1 consists of the existence of a pathological (CTG) triplet expansion in the 3′ untranslated region (UTR) of the Dystrophia Myotonica Protein Kinase (DMPK) gene, whereas (CCTG)n repeats in the first intron of the Cellular Nucleic acid Binding Protein/Zinc Finger Protein 9 (CNBP/ZNF9) gene cause DM2. The expansions are transcribed into (CUG)n and (CCUG)n-containing RNA, respectively, which form secondary structures and sequester RNA-binding proteins, such as the splicing factor muscleblind-like protein (MBNL), forming nuclear aggregates known as foci. Other splicing factors, such as CUGBP, are also disrupted, leading to a spliceopathy of a large number of downstream genes linked to the clinical features of these diseases. Skeletal muscle regeneration relies on muscle progenitor cells, known as satellite cells, which are activated after muscle damage, and which proliferate and differentiate to muscle cells, thus regenerating the damaged tissue. Satellite cell dysfunction seems to be a common feature of both age-dependent muscle degeneration (sarcopenia) and muscle wasting in DM and other muscle degenerative diseases. This review aims to describe the cellular, molecular and macrostructural processes involved in the

  10. Respiratory Muscle Plasticity

    PubMed Central

    Gransee, Heather M.; Mantilla, Carlos B.; Sieck, Gary C.

    2014-01-01

    Muscle plasticity is defined as the ability of a given muscle to alter its structural and functional properties in accordance with the environmental conditions imposed on it. As such, respiratory muscle is in a constant state of remodeling, and the basis of muscle’s plasticity is its ability to change protein expression and resultant protein balance in response to varying environmental conditions. Here, we will describe the changes of respiratory muscle imposed by extrinsic changes in mechanical load, activity, and innervation. Although there is a large body of literature on the structural and functional plasticity of respiratory muscles, we are only beginning to understand the molecular-scale protein changes that contribute to protein balance. We will give an overview of key mechanisms regulating protein synthesis and protein degradation, as well as the complex interactions between them. We suggest future application of a systems biology approach that would develop a mathematical model of protein balance and greatly improve treatments in a variety of clinical settings related to maintaining both muscle mass and optimal contractile function of respiratory muscles. PMID:23798306

  11. Chronic exercise preserves lean muscle mass in masters athletes.

    PubMed

    Wroblewski, Andrew P; Amati, Francesca; Smiley, Mark A; Goodpaster, Bret; Wright, Vonda

    2011-09-01

    Aging is commonly associated with a loss of muscle mass and strength, resulting in falls, functional decline, and the subjective feeling of weakness. Exercise modulates the morbidities of muscle aging. Most studies, however, have examined muscle-loss changes in sedentary aging adults. This leaves the question of whether the changes that are commonly associated with muscle aging reflect the true physiology of muscle aging or whether they reflect disuse atrophy. This study evaluated whether high levels of chronic exercise prevents the loss of lean muscle mass and strength experienced in sedentary aging adults. A cross-section of 40 high-level recreational athletes ("masters athletes") who were aged 40 to 81 years and trained 4 to 5 times per week underwent tests of health/activity, body composition, quadriceps peak torque (PT), and magnetic resonance imaging of bilateral quadriceps. Mid-thigh muscle area, quadriceps area (QA), subcutaneous adipose tissue, and intramuscular adipose tissue were quantified in magnetic resonance imaging using medical image processing, analysis, and visualization software. One-way analysis of variance was used to examine age group differences. Relationships were evaluated using Spearman correlations. Mid-thigh muscle area (P = 0.31) and lean mass (P = 0.15) did not increase with age and were significantly related to retention of mid-thigh muscle area (P < 0.0001). This occurred despite an increase in total body fat percentage (P = 0.003) with age. Mid-thigh muscle area (P = 0.12), QA (P = 0.17), and quadriceps PT did not decline with age. Specific strength (strength per QA) did not decline significantly with age (P = 0.06). As muscle area increased, PT increased significantly (P = 0.008). There was not a significant relationship between intramuscular adipose tissue (P = 0.71) or lean mass (P = 0.4) and PT. This study contradicts the common observation that muscle mass and strength decline as a function of aging alone. Instead, these

  12. Spectrum of Mathematical Weaknesses: Related Neuropsychological Correlates.

    PubMed

    Perna, Robert; Loughan, Ashlee R; Le, Jessica; Hertza, Jeremy; Cohen, Morris J

    2015-01-01

    Math disorders have been recognized for as long as language disorders yet have received far less research. Mathematics is a complex construct and its development may be dependent on multiple cognitive abilities. Several studies have shown that short-term memory, working memory, visuospatial skills, processing speed, and various language skills relate to and may facilitate math development and performance. The hypotheses explored in this research were that children who performed worse on math achievement than on Full-Scale IQ would exhibit weaknesses in executive functions, memory, and visuoperceptual skills. Participants included 436 children (27% girls, 73% boys; age range = 5-17 years, M(age) = 9.45 years) who were referred for neuropsychological evaluations due to academic and/or behavioral problems. This article specifically focuses on the spectrum of math weakness rather than clinical disability, which has yet to be investigated in the literature. Results suggest that children with relative weakness to impairments in math were significantly more likely to have cognitive weaknesses to impairments on neuropsychological variables, as compared with children without math weaknesses. Specifically, the math-weak children exhibit a weakness to impairment on measures involving attention, language, visuoperceptual skills, memory, reading, and spelling. Overall, our results suggest that math development is multifaceted. PMID:25117216

  13. Relationship between muscle volume and muscle torque of the hamstrings after anterior cruciate ligament reconstruction.

    PubMed

    Konishi, Yu; Fukubayashi, Toru

    2010-01-01

    The muscle torque per unit volume of the hamstrings on the injured and uninjured sides in patients with ACL reconstruction were compared with participants with no history of knee injury to examine whether a similar mechanism leading to quadriceps weakness exists in the hamstrings of these patients. The study population consisted of 18 and 52 patients at muscle torque per unit volume, the peak torque of knee flexion was divided by the hamstring volume. Most muscle torque per unit volume indexes were not significantly different between the patients at muscle torque per unit volume of patients at 12 months in both injured (0.118+/-0.03 Nm/cm(3), 60 degrees /s; 0.092+/-0.02 Nm/cm(3), 180 degrees /s) and uninjured sides (0.120+/-0.03 Nm/cm(3) at 60 degrees /s; 0.094+/-0.02 Nm/cm(3), 180 degrees /s) were significantly lower than those of controls (P<0.01). We found no evidence of recruitment disorder in the hamstrings of the patients. The results of this study indicated that the mechanism of muscle weakness of the hamstrings after reconstruction was different from that of the quadriceps, although the precise mechanism remains to be determined.

  14. Experiment K-6-09. Morphological and biochemical investigation of microgravity-induced nerve and muscle breakdown. Part 1: Investigation of nerve and muscle breakdown during spaceflight; Part 2: Biochemical analysis of EDL and PLT muscles

    NASA Technical Reports Server (NTRS)

    Riley, D. A.; Ellis, S.; Bain, J.; Sedlak, F.; Slocum, G.; Oganov, V.

    1990-01-01

    The present findings on rat hindlimb muscles suggest that skeletal muscle weakness induced by prolonged spaceflight can result from a combination of muscle fiber atrophy, muscle fiber segmental necrosis, degeneration of motor nerve terminals and destruction of microcirculatory vessels. Damage was confined to the red adductor longus (AL) and soleus muscles. The midbelly region of the AL muscle had more segmental necrosis and edema than the ends. Macrophages and neutrophils were the major mononucleated cells infiltrating and phagocytosing the cellular debris. Toluidine blue-positive mast cells were significantly decreased in Flight AL muscles compared to controls; this indicated that degranulation of mast cells contributed to tissue edema. Increased ubiquitination of disrupted myofibrils may have promoted myofilament degradation. Overall, mitochondria content and SDH activity were normal, except for a decrease in the subsarcolemmal region. The myofibrillar ATPase activity shifted toward the fast type in the Flight AL muscles. Some of the pathological changes may have occurred or been exacerbated during the 2 day postflight period of readaptation to terrestrial gravity. While simple atrophy should be reversible by exercise, restoration of pathological changes depends upon complex processes of regeneration by stem cells. Initial signs of muscle and nerve fiber regeneration were detected. Even though regeneration proceeds on Earth, the space environment may inhibit repair and cause progressive irreversible deterioration during long term missions. Muscles obtained from Flight rats sacrificed immediately (within a few hours) after landing are needed to distinguish inflight changes from postflight readaptation.

  15. Structural features of sequential weak measurements

    NASA Astrophysics Data System (ADS)

    Diósi, Lajos

    2016-07-01

    We discuss the abstract structure of sequential weak measurement (WM) of general observables. In all orders, the sequential WM correlations without postselection yield the corresponding correlations of the Wigner function, offering direct quantum tomography through the moments of the canonical variables. Correlations in spin-1/2 sequential weak measurements coincide with those in strong measurements, they are constrained kinematically, and they are equivalent with single measurements. In sequential WMs with postselection, an anomaly occurs, different from the weak value anomaly of single WMs. In particular, the spread of polarization σ ̂ as measured in double WMs of σ ̂ will diverge for certain orthogonal pre- and postselected states.

  16. Complex weak values in quantum measurement

    SciTech Connect

    Jozsa, Richard

    2007-10-15

    In the weak value formalism of Aharonov et al., the weak value A{sub w} of any observable A is generally a complex number. We derive a physical interpretation of its value in terms of the shift in the measurement pointer's mean position and mean momentum. In particular, we show that the mean position shift contains a term jointly proportional to the imaginary part of the weak value and the rate at which the pointer is spreading in space as it enters the measurement interaction.

  17. Weak side of strong topological insulators

    NASA Astrophysics Data System (ADS)

    Sbierski, Björn; Schneider, Martin; Brouwer, Piet W.

    2016-04-01

    Strong topological insulators may have nonzero weak indices. The nonzero weak indices allow for the existence of topologically protected helical states along line defects of the lattice. If the lattice admits line defects that connect opposite surfaces of a slab of such a "weak-and-strong" topological insulator, these states effectively connect the surface states at opposite surfaces. Depending on the phases accumulated along the dislocation lines, this connection results in a suppression of in-plane transport and the opening of a spectral gap or in an enhanced density of states and an increased conductivity.

  18. Age at spinal cord injury determines muscle strength

    PubMed Central

    Thomas, Christine K.; Grumbles, Robert M.

    2014-01-01

    As individuals with spinal cord injury (SCI) age they report noticeable deficits in muscle strength, endurance and functional capacity when performing everyday tasks. These changes begin at ~45 years. Here we present a cross-sectional analysis of paralyzed thenar muscle and motor unit contractile properties in two datasets obtained from different subjects who sustained a cervical SCI at different ages (≤46 years) in relation to data from uninjured age-matched individuals. First, completely paralyzed thenar muscles were weaker when C6 SCI occurred at an older age. Muscles were also significantly weaker if the injury was closer to the thenar motor pools (C6 vs. C4). More muscles were strong (>50% uninjured) in those injured at a younger (≤25 years) vs. young age (>25 years), irrespective of SCI level. There was a reduction in motor unit numbers in all muscles tested. In each C6 SCI, only ~30 units survived vs. 144 units in uninjured subjects. Since intact axons only sprout 4–6 fold, the limits for muscle reinnervation have largely been met in these young individuals. Thus, any further reduction in motor unit numbers with time after these injuries will likely result in chronic denervation, and may explain the late-onset muscle weakness routinely described by people with SCI. In a second dataset, paralyzed thenar motor units were more fatigable than uninjured units. This gap widened with age and will reduce functional reserve. Force declines were not due to electromyographic decrements in either group so the site of failure was beyond excitation of the muscle membrane. Together, these results suggest that age at SCI is an important determinant of long-term muscle strength, and fatigability, both of which influence functional capacity. PMID:24478643

  19. The importance of alcohol-induced muscle disease.

    PubMed

    Preedy, Victor R; Ohlendieck, Kay; Adachi, Junko; Koll, Michael; Sneddon, Alan; Hunter, Ross; Rajendram, Rajkumar; Mantle, David; Peters, Timothy J

    2003-01-01

    Alcohol-induced muscle disease (AIMD) is a composite term to describe any muscle pathology (molecular, biochemical, structural or physiological) resulting from either acute or chronic alcohol ingestion or a combination thereof. The chronic form of AIMD is arguably the most prevalent skeletal muscle disorder in the Western Hemisphere affecting more than 2000 subjects per 100,000 population and is thus much more common than hereditary disorders such as Becker or Duchenne muscular dystrophy. Paradoxically, most texts on skeletal myopathies or scientific meetings covering muscle disease have generally ignored chronic alcoholic myopathy. The chronic form of AIMDs affects 40-60% of alcoholics and is more common than other alcohol-induced diseases, for example, cirrhosis (15-20% of chronic alcoholics), peripheral neuropathy (15-20%), intestinal disease (30-50%) or cardiomyopathy (15-35%). In this article, we summarise the pathological features of alcoholic muscle disease, particularly biochemical changes related to protein metabolism and some of the putative underlying mechanisms. However, the intervening steps between the exposure of muscle to ethanol and the initiation of the cascade of responses leading to muscle weakness and loss of muscle bulk remain essentially unknown. We argue that alcoholic myopathy represents: (a) a model system in which both the causal agent and the target organ is known; (b) a myopathy involving free-radical mediated pathology to the whole body which may also target skeletal muscle and (c) a reversible myopathy, unlike many hereditary muscle diseases. A clearer understanding of the mechanisms responsible for alcoholic myopathy is important since some of the underlying pathways may be common to other myopathies.

  20. Muscle Activation during Gait in Children with Duchenne Muscular Dystrophy

    PubMed Central

    Vuillerot, Carole; Tiffreau, Vincent; Peudenier, Sylviane; Cuisset, Jean-Marie; Pereon, Yann; Leboeuf, Fabien; Delporte, Ludovic; Delpierre, Yannick; Gross, Raphaël

    2016-01-01

    The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity. PMID:27622734

  1. Muscle Activation during Gait in Children with Duchenne Muscular Dystrophy.

    PubMed

    Ropars, Juliette; Lempereur, Mathieu; Vuillerot, Carole; Tiffreau, Vincent; Peudenier, Sylviane; Cuisset, Jean-Marie; Pereon, Yann; Leboeuf, Fabien; Delporte, Ludovic; Delpierre, Yannick; Gross, Raphaël; Brochard, Sylvain

    2016-01-01

    The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity. PMID:27622734

  2. Nebulin, a major player in muscle health and disease.

    PubMed

    Labeit, Siegfried; Ottenheijm, Coen A C; Granzier, Henk

    2011-03-01

    Nebulin is a giant 600- to 900-kDa filamentous protein that is an integral component of the skeletal muscle thin filament. Its functions have remained largely nebulous because of its large size and the difficulty in extracting nebulin in a native state from muscle. Recent improvements in the field, especially the development of knockout mouse models deficient in nebulin (NEB-KO mice), indicate now that nebulin performs a surprisingly wide range of functions. In addition to a major role in thin-filament length specification, nebulin also functions in the regulation of muscle contraction, as indicated by the findings that muscle fibers deficient in nebulin have a higher tension cost, and develop less force due to reduced myofilament calcium sensitivity and altered crossbridge cycling kinetics. In addition, the function of nebulin extends to a role in calcium homeostasis. These novel functions indicate that nebulin might have evolved in vertebrate skeletal muscles to develop high levels of muscle force efficiently. Finally, the NEB-KO mouse models also highlight the role of nebulin in the assembly and alignment of the Z disks. Notably, rapid progress in understanding the roles of nebulin in vivo provides clinically important insights into how nebulin deficiency in patients with nemaline myopathy contributes to debilitating muscle weakness. PMID:21115852

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

    PubMed Central

    Diogo, R; Tanaka, E M

    2012-01-01

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

  4. Characterizing upper limb muscle volume and strength in older adults: a comparison with young adults.

    PubMed

    Vidt, Meghan E; Daly, Melissa; Miller, Michael E; Davis, Cralen C; Marsh, Anthony P; Saul, Katherine R

    2012-01-10

    Aging is associated with the loss of muscle volume (MV) and force leading to difficulties with activities of daily living. However, the relationship between upper limb MV and joint strength has not been characterized for older adults. Quantifying this relationship may help our understanding of the functional declines of the upper limb that older adults experience. Our objective was to assess the relationship between upper limb MV and maximal isometric joint moment-generating capacity (IJM) in a single cohort of healthy older adults (age ≥ 65 years) for 6 major functional groups (32 muscles). MV was determined from MRI for 18 participants (75.1±4.3 years). IJM at the shoulder (abduction/adduction), elbow (flexion/extension), and wrist (flexion/extension) was measured. MV and IJM measurements were compared to previous reports for young adults (28.6±4.5 years). On average older adults had 16.5% less total upper limb MV compared to young adults. Additionally, older adult wrist extensors composed a significantly increased percentage of upper limb MV. Older adult IJM was reduced across all joints, with significant differences for shoulder abductors (p<0.0001), adductors (p=0.01), and wrist flexors (p<0.0001). Young adults were strongest at the shoulder, which was not the case for older adults. In older adults, 40.6% of the variation in IJM was accounted for by MV changes (p≤0.027), compared to 81.0% in young adults. We conclude that for older adults, MV and IJM are, on average, reduced but the significant linear relationship between MV and IJM is maintained. These results suggest that older adult MV and IJM cannot be simply scaled from young adults.

  5. Skeletal muscle response to inflammation--lessons for chronic obstructive pulmonary disease.

    PubMed

    Reid, W Darlene; Rurak, Jennifer; Harris, R Luke

    2009-10-01

    To describe how inflammation affects muscle adaptation and performance in people with chronic obstructive pulmonary disease. In chronic obstructive pulmonary disease, an increasingly sedentary lifestyle is a primary contributor to muscle dysfunction that results in a loss of mobility and independence and, ultimately, mortality. Given the systemic chronic inflammation and profound limb muscle atrophy in chronic obstructive pulmonary disease, it is tempting to speculate that the inflammatory process is deleterious to skeletal muscle. In healthy people, however, the inflammatory process initially is dominated by a destructive phase that is tightly regulated and modulates a reparative, regenerative phase. Although the inflammatory process and associated oxidative stress is more closely connected to muscle wasting in animal models of chronic obstructive pulmonary disease, the causative role of inflammation toward muscle atrophy and weakness in people with chronic obstructive pulmonary disease has not been definitively shown. Anti-inflammatory interventions aimed toward tempering muscle wasting and weakness in chronic obstructive pulmonary disease may not prove to be beneficial because of longer-term disruption of the regeneration of muscle tissue. Temporally and spatially targeted interventions aimed toward ameliorating oxidative stress, such as antioxidants, nutritional supplements, and chronic exercise training, may optimize outcomes toward maintaining muscle mass and performance.

  6. Muscles of the Trunk

    MedlinePlus

    ... Home » Cancer Registration & Surveillance Modules » Anatomy & Physiology » Muscular System » Muscle Groups » Trunk Cancer Registration & Surveillance Modules Anatomy & Physiology Intro to the Human Body Body Functions & Life Process Anatomical Terminology Review Quiz ...

  7. Neurogenic muscle cramps.

    PubMed

    Katzberg, Hans D

    2015-08-01

    Muscle cramps are sustained, painful contractions of muscle and are prevalent in patients with and without medical conditions. The objective of this review is to present updates on the mechanism, investigation and treatment of neurogenic muscle cramps. PubMed and Embase databases were queried between January 1980 and July 2014 for English-language human studies. The American Academy of Neurology classification of studies (classes I-IV) was used to assess levels of evidence. Mechanical disruption, ephaptic transmission, disruption of sensory afferents and persistent inward currents have been implicated in the pathogenesis of neurogenic cramps. Investigations are directed toward identifying physiological triggers or medical conditions predisposing to cramps. Although cramps can be self-limiting, disabling or sustained muscle cramps should prompt investigation for underlying medical conditions. Lifestyle modifications, treatment of underlying conditions, stretching, B-complex vitamins, diltiezam, mexiletine, carbamazepine, tetrahydrocannabinoid, leveteracitam and quinine sulfate have shown evidence for treatment. PMID:25673127

  8. Muscle biopsy (image)

    MedlinePlus

    A muscle biopsy involves removal of a plug of tissue usually by a needle to be later used for examination. Sometimes ... there is a patchy condition expected an open biopsy may be used. Open biopsy involves a small ...

  9. Competition between weak localization and ballistic transport.

    PubMed

    Tian, Chushun

    2009-06-19

    High-frequency transport in perfect periodic dielectric cylinder arrays is studied. We analytically calculate the diffusive-ballistic transport crossover, which displays the competition between weak localization and ballistic transport. PMID:19659008

  10. Sodium in weak G-band giants

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy J.; Lambert, David L.

    1994-01-01

    Sodium abundances have been determined for eight weak G-band giants whose atmospheres are greatly enriched with products of the CN-cycling H-burning reactions. Systematic errors are minimized by comparing the weak G-band giants to a sample of similar but normal giants. If, further, Ca is selected as a reference element, model atmosphere-related errors should largely be removed. For the weak-G-band stars (Na/Ca) = 0.16 +/- 0.01, which is just possibly greater than the result (Na/Ca) = 0.10 /- 0.03 from the normal giants. This result demonstrates that the atmospheres of the weak G-band giants are not seriously contaminated with products of ON cycling.

  11. Parametric instabilities in weakly magnetized plasma

    SciTech Connect

    Weatherall, J.C.; Goldman, M.V.; Nicholson, D.R.

    1981-05-15

    Parametric instabilities in a weakly magnetized plasma are discussed. The results are applied to waves excited by electron streams which travel outward from the Sun along solar-wind magnetic field lines, as in a type III solar radio burst.

  12. Sensor/amplifier for weak light sources

    NASA Technical Reports Server (NTRS)

    Desmet, D. J.; Jason, A. J.; Parr, A. C.

    1980-01-01

    Light sensor/amplifier circuit detects weak light converts it into strong electrical signal in electrically noisy environment. Circuit is relatively simple and uses inexpensive, readily available components. Device is useful in such applications as fire detection and photographic processing.

  13. Experimental studies of weakly coupled superconductors (Review)

    NASA Astrophysics Data System (ADS)

    Dmitrenko, I. M.

    2004-07-01

    A review is given of the main experimental results obtained in research on weakly coupled superconductors after 1964 at the Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Kharkov (ILTPE).

  14. Research opportunities in muscle atrophy

    NASA Technical Reports Server (NTRS)

    Herbison, G. J. (Editor); Talbot, J. M. (Editor)

    1984-01-01

    Muscle atrophy in a weightless environment is studied. Topics of investigation include physiological factors of muscle atrophy in space flight, biochemistry, countermeasures, modelling of atrophied muscle tissue, and various methods of measurement of muscle strength and endurance. A review of the current literature and suggestions for future research are included.

  15. Muscle Fiber Types and Training.

    ERIC Educational Resources Information Center

    Karp, Jason R.

    2001-01-01

    The specific types of fibers that make up individual muscles greatly influence how people will adapt to their training programs. This paper explains the complexities of skeletal muscles, focusing on types of muscle fibers (slow-twitch and fast-twitch), recruitment of muscle fibers to perform a motor task, and determining fiber type. Implications…

  16. The vestibular system does not modulate fusimotor drive to muscle spindles in contracting leg muscles of seated subjects.

    PubMed

    Bent, L R; Sander, M; Bolton, P S; Macefield, V G

    2013-06-01

    We previously showed that sinusoidal galvanic vestibular stimulation (GVS) does not modulate the firing of spontaneously active muscle spindles in relaxed human leg muscles. However, given that there is little, if any, fusimotor drive to relaxed human muscles, we tested the hypothesis that vestibular modulation of muscle spindles becomes apparent during volitional contractions at levels that engage the fusimotor system. Unitary recordings were made from 28 muscle spindle afferents via tungsten microelectrodes inserted percutaneously into the common peroneal nerve of seated awake human subjects. Twenty-one of the spindle afferents were spontaneously active at rest and each increased its firing rate during a weak static contraction; seven were silent at rest and were recruited during the contraction. Sinusoidal bipolar binaural galvanic vestibular stimulation (±2 mA, 100 cycles) was applied to the mastoid processes at 0.8 Hz. This continuous stimulation produced a sustained illusion of "rocking in a boat" or "swinging in a hammock" but no entrainment of EMG. Despite these robust vestibular illusions, none of the fusimotor-driven muscle spindles exhibited phase-locked modulation of firing during sinusoidal GVS. We conclude that this dynamic vestibular input was not sufficient to modulate the firing of fusimotor neurones recruited during a voluntary steady-state contraction, arguing against a significant role of the vestibular system in adjusting the sensitivity of muscle spindles via fusimotor neurones. PMID:23552997

  17. Artificial muscle: the human chimera is the future.

    PubMed

    Tozzi, P

    2011-12-14

    Severe heart failure and cerebral stroke are broadly associated with the impairment of muscular function that conventional treatments struggle to restore. New technologies enable the construction of "smart" materials that could be of great help in treating diseases where the main problem is muscle weakness. These materials "behave" similarly to biological systems, because the material directly converts energy, for example electrical energy into movement. The extension and contraction occur silently like in natural muscles. The real challenge is to transfer this amazing technology into devices that restore or replace the mechanical function of failing muscle. Cardiac assist devices based on artificial muscle technology could envelope a weak heart and temporarily improve its systolic function, or, if placed on top of the atrium, restore the atrial kick in chronic atrial fibrillation. Artificial sphincters could be used to treat urinary incontinence after prostatectomy or faecal incontinence associated with stomas. Artificial muscles can restore the ability of patients with facial paralysis due to stroke or nerve injury to blink. Smart materials could be used to construct an artificial oesophagus including peristaltic movement and lower oesophageal sphincter function to replace the diseased oesophagus thereby avoiding the need for laparotomy to mobilise stomach or intestine. In conclusion, in the near future, smart devices will integrate with the human body to fill functional gaps due to organ failure, and so create a human chimera.

  18. Poor physical function in elderly women in low-level aged care is related to muscle strength rather than to measures of sarcopenia

    PubMed Central

    Woods, Julie L; Iuliano-Burns, Sandra; King, Susannah J; Strauss, Boyd J; Walker, Karen Z

    2011-01-01

    Purpose: To determine the prevalence of sarcopenia and investigate relationships among body composition, muscle strength, and physical function in elderly women in low-level aged care. Subjects and methods: Sixty-three ambulatory women (mean age 86 years) participated in this cross-sectional study where body composition was determined by dual energy X-ray absorptiometry (DXA); ankle, knee, and hip strength by the Nicholas Manual Muscle Tester; and physical function by ‘timed up and go’ (TUG) and walking speed (WS) over 6 meters. Body composition data from a female reference group (n = 62, mean age 29 years) provided cut-off values for defining sarcopenia. Results: Elderly women had higher body mass index (P < 0.001), lower lean mass (P < 0.001), and higher fat mass (P < 0.01) than the young reference group. Only a small proportion (3.2%) had absolute sarcopenia (defined by appendicular skeletal muscle mass/height squared) whereas 37% had relative sarcopenia class II (defined by percentage skeletal muscle mass). Scores for TUG and WS indicated relatively poor physical function, yet these measures were not associated with muscle mass or indices of sarcopenia. In multivariate analysis, only hip abductor strength predicted both TUG and WS (both P = 0.01). Conclusion: Hip strength is a more important indicator of physical functioning than lean mass. Measurement of hip strength may therefore be a useful screening tool to detect those at risk of functional decline and requirement for additional care. Further longitudinal studies with a range of other strength measures are warranted. PMID:21472094

  19. An invertebrate smooth muscle with striated muscle myosin filaments

    PubMed Central

    Sulbarán, Guidenn; Alamo, Lorenzo; Pinto, Antonio; Márquez, Gustavo; Méndez, Franklin; Padrón, Raúl; Craig, Roger

    2015-01-01

    Muscle tissues are classically divided into two major types, depending on the presence or absence of striations. In striated muscles, the actin filaments are anchored at Z-lines and the myosin and actin filaments are in register, whereas in smooth muscles, the actin filaments are attached to dense bodies and the myosin and actin filaments are out of register. The structure of the filaments in smooth muscles is also different from that in striated muscles. Here we have studied the structure of myosin filaments from the smooth muscles of the human parasite Schistosoma mansoni. We find, surprisingly, that they are indistinguishable from those in an arthropod striated muscle. This structural similarity is supported by sequence comparison between the schistosome myosin II heavy chain and known striated muscle myosins. In contrast, the actin filaments of schistosomes are similar to those of smooth muscles, lacking troponin-dependent regulation. We conclude that schistosome muscles are hybrids, containing striated muscle-like myosin filaments and smooth muscle-like actin filaments in a smooth muscle architecture. This surprising finding has broad significance for understanding how muscles are built and how they evolved, and challenges the paradigm that smooth and striated muscles always have distinctly different components. PMID:26443857

  20. Some Topics in Weak and Electromagnetic Interactions

    NASA Astrophysics Data System (ADS)

    Bjorken, James D.

    1982-01-01

    The following sections are included: * INTRODUCTION * LECTURE I QUANTUM-ELECTRODYNAMICS TESTS; TESTS OF Jμ Jμ STRUCTURE IN WEAK INTERACTIONS; HIGHER-ORDER WEAK INTERACTIONS * LECTURE II PHENOMENOLOGY OF DEEP-INELASTIC PROCESSES; NO FINAL-STATE HADRONS OBSERVED * LECTURE III LIGHT-CONE COMMUTATORS; MODELS OF THE STRUCTURE FUNCTIONS * LECTURE IV HADRON FINAL STATES IN DEEP-INELASTIC PROCESSES; GENERAL CONSIDERATIONS * LECTURE V INCLUSIVE PROCESSES AT VERY HIGH TRANSVERSE MOMENTUM * REFERENCES

  1. Deterministic implementation of weak quantum cubic nonlinearity

    SciTech Connect

    Marek, Petr; Filip, Radim; Furusawa, Akira

    2011-11-15

    We propose a deterministic implementation of weak cubic nonlinearity, which is a basic building block of a full-scale continuous-variable quantum computation. Our proposal relies on preparation of a specific ancillary state and transferring its nonlinear properties onto the desired target by means of deterministic Gaussian operations and feed forward. We show that, despite the imperfections arising from the deterministic nature of the operation, the weak quantum nonlinearity can be implemented and verified with the current level of technology.

  2. Looking for heavier weak bosons with DUMAND

    NASA Technical Reports Server (NTRS)

    Brown, R. W.; Stecker, F. W.

    1980-01-01

    One or more heavier weak bosons may coexist with the standard weak boson, a broad program may be laid out for a search for the heavier W's via change in the total cross section due to the additional propagator, a concomitant search, and a subsequent search for significant antimatter in the universe involving the same annihilation, but being independent of possible neutrino oscillations. The program is likely to require detectors sensitive to higher energies, such as acoustic detectors.

  3. Electromagnetic and Weak transitions in light nuclei

    SciTech Connect

    M. Viviani; L.E. Marcucci; A. Kievsky; S. Rosati; R. Schiavilla

    2002-09-01

    Recent advances in the study of the p -- d radiative and mu -- {sup 3}He weak capture processes by our group are presented and discussed. The trinucleon bound and scattering states have been obtained from variational calculations by expanding the corresponding wave functions in terms of correlated hyper-spherical harmonic functions. The electromagnetic and weak transition currents include one- and two-body operators. The accuracy achieved in these calculations allows for interesting comparisons with experimental data.

  4. Bound potassium in muscle II.

    PubMed

    Hummel, Z

    1980-01-01

    Experiments were performed to decide between the alternatives a) the ionized K+ is in a dissolved state in the muscle water, or b) a part of the muscle potassium is in a "bound' state. Sartorius muscles of Rana esculenta were put into glicerol for about one hour at 0-2 degrees C. Most of muscle water came out, but most of muscle potassium remained in the muscles. In contrast to this: from muscle in heat rigor more potassium was released due to glicerol treating than from the intact ones. 1. Supposition a) is experimentally refuted. 2. Supposition b) corresponds to the experimental results. PMID:6969511

  5. OBLIQUELY STRIATED MUSCLE

    PubMed Central

    Rosenbluth, Jack

    1967-01-01

    Segments of the obliquely striated body muscle of Ascaris were fixed at minimum body length after treatment with acetylcholine and at maximum body length after treatment with piperazine citrate and then studied by light and electron microscopy. Evidence was found for two mechanisms of length change: sliding of thin filaments with respect to thick filaments such as occurs in cross-striated muscle, and shearing of thick filaments with respect to each other such that the degree of their stagger increases with extension and decreases with shortening. The shearing mechanism could account for great extensibility in this muscle and in nonstriated muscles in general and could underlie other manifestations of "plasticity" as well. In addition, it is suggested that the contractile apparatus is attached to the endomysium in such a way that the sarcomeres can act either in series, as in cross-striated muscle, or individually. Since the sarcomeres are virtually longitudinal in orientation and are almost coextensive with the muscle fiber, it would, therefore, be possible for a single sarcomere contracting independently to develop tension effectively between widely separated points on the fiber surface, thus permitting very efficient maintenance of isometric tension. PMID:6040534

  6. Head muscle development.

    PubMed

    Tzahor, Eldad

    2015-01-01

    The developmental paths that lead to the formation of skeletal muscles in the head are distinct from those operating in the trunk. Craniofacial muscles are associated with head and neck structures. In the embryo, these structures derive from distinct mesoderm populations. Distinct genetic programs regulate different groups of muscles within the head to generate diverse muscle specifications. Developmental and lineage studies in vertebrates and invertebrates demonstrated an overlap in progenitor populations derived from the pharyngeal mesoderm that contribute to certain head muscles and the heart. These studies reveal that the genetic program controlling pharyngeal muscles overlaps with that of the heart. Indeed cardiac and craniofacial birth defects are often linked. Recent studies suggest that early chordates, the last common ancestor of tunicates and vertebrates, had an ancestral pharyngeal mesoderm lineage that later during evolution gave rise to both heart and craniofacial structures. This chapter summarizes studies related to the origins, signaling, genetics, and evolution of the head musculature, highlighting its heterogeneous characteristics in all these aspects.

  7. Monomelic muscle hypertrophy following transient ischemic attacks: a case report.

    PubMed

    Isaacs, E R; Larson, P

    1978-01-01

    A 39-year-old right-handed male suffered several episodes of transient right-sided weakness, sensory loss, and Broca's aphasia at age 31. Diagnostic studies failed to demonstrate any cause for these events. Following a complete recovery, he noted the onset of stiffness and increasing muscle bulk in his right arm, which gradually restricted its use. Simultaneous recordings from contracting biceps and triceps muscles in both arms suggested that the hypertrophy was physiologically induced by an abnormal mechanism providing resistance during phasing activity. PMID:750924

  8. Severe neuromuscular denervation of clinically relevant muscles in a mouse model of spinal muscular atrophy.

    PubMed

    Ling, Karen K Y; Gibbs, Rebecca M; Feng, Zhihua; Ko, Chien-Ping

    2012-01-01

    Spinal muscular atrophy (SMA), a motoneuron disease caused by a deficiency of the survival of motor neuron (SMN) protein, is characterized by motoneuron loss and muscle weakness. It remains unclear whether widespread loss of neuromuscular junctions (NMJs) is involved in SMA pathogenesis. We undertook a systematic examination of NMJ innervation patterns in >20 muscles in the SMNΔ7 SMA mouse model. We found that severe denervation (<50% fully innervated endplates) occurs selectively in many vulnerable axial muscles and several appendicular muscles at the disease end stage. Since these vulnerable muscles were located throughout the body and were comprised of varying muscle fiber types, it is unlikely that muscle location or fiber type determines susceptibility to denervation. Furthermore, we found a similar extent of neurofilament accumulation at NMJs in both vulnerable and resistant muscles before the onset of denervation, suggesting that neurofilament accumulation does not predict subsequent NMJ denervation. Since vulnerable muscles were initially innervated, but later denervated, loss of innervation in SMA may be attributed to defects in synapse maintenance. Finally, we found that denervation was amendable by trichostatin A (TSA) treatment, which increased innervation in clinically relevant muscles in TSA-treated SMNΔ7 mice. Our findings suggest that neuromuscular denervation in vulnerable muscles is a widespread pathology in SMA, and can serve as a preparation for elucidating the biological basis of synapse loss, and for evaluating therapeutic efficacy.

  9. Role of reactive oxygen species in the defective regeneration seen in aging muscle.

    PubMed

    Vasilaki, Aphrodite; Jackson, Malcolm J

    2013-12-01

    The ability of muscles to regenerate successfully following damage diminishes with age and this appears to be a major contributor to the development of muscle weakness and physical frailty. Successful muscle regeneration is dependent on appropriate reinnervation of regenerating muscle. Age-related changes in the interactions between nerve and muscle are poorly understood but may play a major role in the defective regeneration. During aging there is defective redox homeostasis and an accumulation of oxidative damage in nerve and muscle that may contribute to defective regeneration. The aim of this review is to summarise the evidence that abnormal reactive oxygen species (ROS) generation in nerve and/or muscle may be responsible for the defective regeneration that contributes to the degeneration of skeletal muscle observed during aging. Identifying the importance of ROS generation in skeletal muscle during aging could have fundamental implications for interventions to prevent muscle degeneration and treatments to reverse the age-related decline in muscle mass and function. PMID:23851030

  10. Botulinum toxin injection to facilitate rehabilitation of muscle imbalance syndromes in sports medicine.

    PubMed

    Cullen, D M; Boyle, J J W; Silbert, P L; Singer, B J; Singer, K P

    2007-12-15

    Intramuscular injection of Botulinum toxin to produce reduction of focal muscle overactivity, and localized muscle spasm, has been utilized therapeutically for almost two decades. Muscle overactivity in neurologically normal muscle, where an imbalance exists between a relatively overactive muscle and its less active synergist or antagonist, can inhibit control of the antagonist producing a functional muscle imbalance. This brief review provides an overview of the role of muscle imbalance in sports-related pain and dysfunction, and outlines the potential for intramuscular injection of Botulinum toxin to be used as an adjunct to specific muscle re-education and functional rehabilitation in this patient group. A comprehensive understanding of normal movement and the requirements of the sporting activity are essential to allow accurate diagnosis of abnormal motor patterns and to re-educate more appropriate movement strategies. Therapeutic management of co-impairments may include stretching of tight soft tissues, specific re-education aimed at isolation of the non-dominant weak muscles and improvement in their activation, 'unlearning' of faulty motor patterns, and eventual progression onto functional exercises to anticipate gradual return to sporting activity. Intramuscular injection of Botulinum toxin, in carefully selected cases, provides short term reduction of focal muscle overactivity, and may facilitate activation of relatively 'inhibited' muscles and assist the restoration of more appropriate motor patterns.

  11. Contractile dysfunction in muscle may underlie androgen-dependent motor dysfunction in spinal bulbar muscular atrophy

    PubMed Central

    Oki, Kentaro; Halievski, Katherine; Vicente, Laura; Xu, Youfen; Zeolla, Donald; Poort, Jessica; Katsuno, Masahisa; Adachi, Hiroaki; Sobue, Gen; Wiseman, Robert W.; Breedlove, S. Marc

    2015-01-01

    Spinal and bulbar muscular atrophy (SBMA) is characterized by progressive muscle weakness linked to a polyglutamine expansion in the androgen receptor (AR). Current evidence indicates that mutant AR causes SBMA by acting in muscle to perturb its function. However, information about how muscle function is impaired is scant. One fundamental question is whether the intrinsic strength of muscles, an attribute of muscle independent of its mass, is affected. In the current study, we assess the contractile properties of hindlimb muscles in vitro from chronically diseased males of three different SBMA mouse models: a transgenic (Tg) model that broadly expresses a full-length human AR with 97 CAGs (97Q), a knock-in (KI) model that expresses a humanized AR containing a CAG expansion in the first exon, and a Tg myogenic model that overexpresses wild-type AR only in skeletal muscle fibers. We found that hindlimb muscles in the two Tg models (97Q and myogenic) showed marked losses in their intrinsic strength and resistance to fatigue, but were minimally affected in KI males. However, diseased muscles of all three models showed symptoms consistent with myotonic dystrophy type 1, namely, reduced resting membrane potential and deficits in chloride channel mRNA. These data indicate that muscle dysfunction is a core feature of SBMA caused by at least some of the same pathogenic mechanisms as myotonic dystrophy. Thus mechanisms controlling muscle function per se independent of mass are prime targets for SBMA therapeutics. PMID:25663674

  12. "Role of reactive oxygen species in the defective regeneration seen in aging muscle."

    PubMed Central

    Vasilaki, Aphrodite; Jackson, Malcolm J.

    2013-01-01

    The ability of muscles to regenerate successfully following damage diminishes with age and this appears to be a major contributor to the development of muscle weakness and physical frailty. Successful muscle regeneration is dependent on appropriate re-innervation of regenerating muscle. Age-related changes in the interactions between nerve and muscle are poorly understood but may play a major role in the defective regeneration. During aging there is defective redox homeostasis and an accumulation of oxidative damage in nerve and muscle that may contribute to defective regeneration. The aim of this review is to summarise the evidence that abnormal Reactive Oxygen Species (ROS) generation in nerve and/or muscle may be responsible for the defective regeneration that contributes to the degeneration of skeletal muscle observed during aging. Identifying the importance of ROS generation in skeletal muscle during aging could have fundamental implications for interventions to prevent muscle degeneration and treatments to reverse the age-related decline in muscle mass and function. PMID:23851030

  13. Contractile dysfunction in muscle may underlie androgen-dependent motor dysfunction in spinal bulbar muscular atrophy.

    PubMed

    Oki, Kentaro; Halievski, Katherine; Vicente, Laura; Xu, Youfen; Zeolla, Donald; Poort, Jessica; Katsuno, Masahisa; Adachi, Hiroaki; Sobue, Gen; Wiseman, Robert W; Breedlove, S Marc; Jordan, Cynthia L

    2015-04-01

    Spinal and bulbar muscular atrophy (SBMA) is characterized by progressive muscle weakness linked to a polyglutamine expansion in the androgen receptor (AR). Current evidence indicates that mutant AR causes SBMA by acting in muscle to perturb its function. However, information about how muscle function is impaired is scant. One fundamental question is whether the intrinsic strength of muscles, an attribute of muscle independent of its mass, is affected. In the current study, we assess the contractile properties of hindlimb muscles in vitro from chronically diseased males of three different SBMA mouse models: a transgenic (Tg) model that broadly expresses a full-length human AR with 97 CAGs (97Q), a knock-in (KI) model that expresses a humanized AR containing a CAG expansion in the first exon, and a Tg myogenic model that overexpresses wild-type AR only in skeletal muscle fibers. We found that hindlimb muscles in the two Tg models (97Q and myogenic) showed marked losses in their intrinsic strength and resistance to fatigue, but were minimally affected in KI males. However, diseased muscles of all three models showed symptoms consistent with myotonic dystrophy type 1, namely, reduced resting membrane potential and deficits in chloride channel mRNA. These data indicate that muscle dysfunction is a core feature of SBMA caused by at least some of the same pathogenic mechanisms as myotonic dystrophy. Thus mechanisms controlling muscle function per se independent of mass are prime targets for SBMA therapeutics.

  14. Muscle Ultrasound in Patients with Glycogen Storage Disease Types I and III.

    PubMed

    Verbeek, Renate J; Sentner, Christiaan P; Smit, G Peter A; Maurits, Natasha M; Derks, Terry G J; van der Hoeven, Johannes H; Sival, Deborah A

    2016-01-01

    In glycogen storage diseases (GSDs), improved longevity has resulted in the need for neuromuscular surveillance. In 12 children and 14 adults with the "hepatic" (GSD-I) and "myopathic" (GSD-III) phenotypes, we cross-sectionally assessed muscle ultrasound density (MUD) and muscle force. Children with both "hepatic" and "myopathic" GSD phenotypes had elevated MUD values (MUD Z-scores: GSD-I > 2.5 SD vs. GSD-III > 1 SD, p < 0.05) and muscle weakness (GSD-I muscle force; p < 0.05) of myopathic distribution. In "hepatic" GSD-I adults, MUD stabilized (GSD-I adults vs. GSD-I children, not significant), concurring with moderate muscle weakness (GSD-I adults vs. healthy matched pairs, p < 0.05). In "myopathic" GSD-III adults, MUD increased with age (MUD-GSD III vs. age: r = 0.71-0.83, GSD-III adults > GSD-III children, p < 0.05), concurring with pronounced muscle weakness (GSD-III adults vs. GSD-I adults, p < 0.05) of myopathic distribution. Children with "hepatic" and "myopathic" GSD phenotypes were both found to have myopathy. Myopathy stabilizes in "hepatic" GSD-I adults, whereas it progresses in "myopathic" GSD-III adults. Muscle ultrasonography provides an excellent, non-invasive tool for neuromuscular surveillance per GSD phenotype.

  15. Muscle hardness characteristics of the masseter muscle after repetitive muscle activation: comparison to the biceps brachii muscle.

    PubMed

    Kashima, Koji; Higashinaka, Shuichi; Watanabe, Naoshi; Maeda, Sho; Shiba, Ryosuke

    2004-10-01

    The purpose of this study was to compare hardness characteristics of the masseter muscle to those of the biceps brachii muscle during repetitive muscle movements. Seventeen asymptomatic female subjects participated in this study. Each subject, on separate days, undertook a 5-minute unilateral chewing gum task on the right side and a 5-minute flexion-extension exercise on the right hand with a 2kg dumbbell. Using a handheld hardness meter, muscle hardness was measured in the right masseter and in the biceps brachii muscle at eight time points (before the task, immediately after the task, and at 1, 3, 5, 10, 30, and 60 minutes after the task), and the data obtained before and after the task on each muscle were compared. Comparisons of the normalized data were also performed between the two muscles at each time point. As a result, a significant increase in muscle hardness was seen at 1 minute after the task in the biceps brachii muscle (p=0.0093). In contrast, the masseter muscle showed a tendency to lower hardness, with the lowest point of hardness occurring at 10 minutes after the task (p = 0.0160). Between the two muscles, there was a difference in the normalized data immediately after the task, and at 1, 5, and 10 minutes after the task (0.01 muscle hardness characteristics of the masseter muscle completely differed from those of the biceps brachii muscle after repetitive muscle activation.

  16. Molecular mechanisms responsible for alcohol-induced myopathy in skeletal muscle and heart.

    PubMed

    Lang, Charles H; Frost, Robert A; Summer, Andrew D; Vary, Thomas C

    2005-10-01

    Chronic alcohol abuse has the potential to modulate striated muscle physiology and function. The skeletal muscle alcoholic myopathy is characterized by muscle weakness and difficulties in gait and locomotion, while chronic alcohol consumption ultimately leads to a decrease in cardiac contractility and output. In both tissues a loss of protein mass results in part from a decreased protein synthesis that initially manifests as a defect in translational efficiency. This review focuses on recent developments in understanding the cellular and molecular mechanisms by which alcohol impairs mRNA translation in skeletal and cardiac muscle, including identification of the signaling pathways and biochemical sites negatively impacted. Defective signaling potentially results from resistance to the normal stimulating effects of anabolic hormones (insulin and insulin-like growth factor-I) and nutrients (leucine) as well as increased production of several negative regulators of muscle mass. Overall, the biochemical mechanisms contributing to the pathogenesis of loss of skeletal and cardiac muscle are reviewed.

  17. Roles of nonmyogenic mesenchymal progenitors in pathogenesis and regeneration of skeletal muscle

    PubMed Central

    Uezumi, Akiyoshi; Ikemoto-Uezumi, Madoka; Tsuchida, Kunihiro

    2014-01-01

    Adult skeletal muscle possesses a remarkable regenerative ability that is dependent on satellite cells. However, skeletal muscle is replaced by fatty and fibrous connective tissue in several pathological conditions. Fatty and fibrous connective tissue becomes a major cause of muscle weakness and leads to further impairment of muscle function. Because the occurrence of fatty and fibrous connective tissue is usually associated with severe destruction of muscle, the idea that dysregulation of the fate switch in satellite cells may underlie this pathological change has emerged. However, recent studies identified nonmyogenic mesenchymal progenitors in skeletal muscle and revealed that fatty and fibrous connective tissue originates from these progenitors. Later, these progenitors were also demonstrated to be the major contributor to heterotopic ossification in skeletal muscle. Because nonmyogenic mesenchymal progenitors represent a distinct cell population from satellite cells, targeting these progenitors could be an ideal therapeutic strategy that specifically prevents pathological changes of skeletal muscle, while preserving satellite cell-dependent regeneration. In addition to their roles in pathogenesis of skeletal muscle, nonmyogenic mesenchymal progenitors may play a vital role in muscle regeneration by regulating satellite cell behavior. Conversely, muscle cells appear to regulate behavior of nonmyogenic mesenchymal progenitors. Thus, these cells regulate each other reciprocally and a proper balance between them is a key determinant of muscle integrity. Furthermore, nonmyogenic mesenchymal progenitors have been shown to maintain muscle mass in a steady homeostatic condition. Understanding the nature of nonmyogenic mesenchymal progenitors will provide valuable insight into the pathophysiology of skeletal muscle. In this review, we focus on nonmyogenic mesenchymal progenitors and discuss their roles in muscle pathogenesis, regeneration, and homeostasis. PMID

  18. Circadian Rhythms, the Molecular Clock, and Skeletal Muscle

    PubMed Central

    Lefta, Mellani; Wolff, Gretchen; Esser, Karyn A.

    2015-01-01

    Almost all organisms ranging from single cell bacteria to humans exhibit a variety of behavioral, physiological, and biochemical rhythms. In mammals, circadian rhythms control the timing of many physiological processes over a 24-h period, including sleep-wake cycles, body temperature, feeding, and hormone production. This body of research has led to defined characteristics of circadian rhythms based on period length, phase, and amplitude. Underlying circadian behaviors is a molecular clock mechanism found in most, if not all, cell types including skeletal muscle. The mammalian molecular clock is a complex of multiple oscillating networks that are regulated through transcriptional mechanisms, timed protein turnover, and input from small molecules. At this time, very little is known about circadian aspects of skeletal muscle function/metabolism but some progress has been made on understanding the molecular clock in skeletal muscle. The goal of this chapter is to provide the basic terminology and concepts of circadian rhythms with a more detailed review of the current state of knowledge of the molecular clock, with reference to what is known in skeletal muscle. Research has demonstrated that the molecular clock is active in skeletal muscles and that the muscle-specific transcription factor, MyoD, is a direct target of the molecular clock. Skeletal muscle of clock-compromised mice, Bmal1−/− and ClockΔ19 mice, are weak and exhibit significant disruptions in expression of many genes required for adult muscle structure and metabolism. We suggest that the interaction between the molecular clock, MyoD, and metabolic factors, such as PGC-1, provide a potential system of feedback loops that may be critical for both maintenance and adaptation of skeletal muscle. PMID:21621073

  19. Circadian rhythms, the molecular clock, and skeletal muscle.

    PubMed

    Lefta, Mellani; Wolff, Gretchen; Esser, Karyn A

    2011-01-01

    Almost all organisms ranging from single cell bacteria to humans exhibit a variety of behavioral, physiological, and biochemical rhythms. In mammals, circadian rhythms control the timing of many physiological processes over a 24-h period, including sleep-wake cycles, body temperature, feeding, and hormone production. This body of research has led to defined characteristics of circadian rhythms based on period length, phase, and amplitude. Underlying circadian behaviors is a molecular clock mechanism found in most, if not all, cell types including skeletal muscle. The mammalian molecular clock is a complex of multiple oscillating networks that are regulated through transcriptional mechanisms, timed protein turnover, and input from small molecules. At this time, very little is known about circadian aspects of skeletal muscle function/metabolism but some progress has been made on understanding the molecular clock in skeletal muscle. The goal of this chapter is to provide the basic terminology and concepts of circadian rhythms with a more detailed review of the current state of knowledge of the molecular clock, with reference to what is known in skeletal muscle. Research has demonstrated that the molecular clock is active in skeletal muscles and that the muscle-specific transcription factor, MyoD, is a direct target of the molecular clock. Skeletal muscle of clock-compromised mice, Bmal1(-/-) and Clock(Δ19) mice, are weak and exhibit significant disruptions in expression of many genes required for adult muscle structure and metabolism. We suggest that the interaction between the molecular clock, MyoD, and metabolic factors, such as PGC-1, provide a potential system of feedback loops that may be critical for both maintenance and adaptation of skeletal muscle.

  20. Wide-pulse electrical stimulation to an intrinsic foot muscle induces acute functional changes in forefoot-rearfoot coupling behaviour during walking.

    PubMed

    James, D C; Chesters, T; Sumners, D P; Cook, D P; Green, D A; Mileva, K N

    2013-05-01

    Interventions for strengthening intrinsic foot muscles may be beneficial for rehabilitation from overuse injuries. In this study the acute effects of high-frequency, low-intensity wide-pulse electrical stimulation (WPS) over an intrinsic muscle on subsequent foot function during walking was assessed in healthy participants. WPS was delivered to the m. abductor hallucis (m.AH) of the non-dominant foot during relaxed standing. 3-dimensional forefoot (FF)--rearfoot (RF) coordination was quantified with a vector coding technique within separate periods of the stance phase to study WPS functional effects on foot motion. 4 types of coordinative strategies between the FF and RF were interpreted and compared PRE-to-POST-WPS for both the experimental and control feet. Bilateral electromyography (EMG) from m.AH was analysed during the intervention period for evidence of acute neuromuscular adaptation. The results showed that WPS significantly modulated FF-RF coordination during mid-stance, indicative of a more stable foot. Specifically, a statistically significant increase in FF eversion with concomitant RF inversion in the frontal plane and RF-dominated adduction in the transverse plane was observed. Subject-specific increases in post-stimulus m.AH EMG activation were observed but this was not reflected in an overall group effect. It is concluded that the structural integrity of the foot during walking is enhanced following an acute session of WPS and that this mechanical effect is most likely due to stimulation induced post-tetanic potentiation of synaptic transmission.

  1. Hadronic Weak Interaction Studies at the SNS

    NASA Astrophysics Data System (ADS)

    Fomin, Nadia

    2016-03-01

    Neutrons have been a useful probe in many fields of science, as well as an important physical system for study in themselves. Modern neutron sources provide extraordinary opportunities to study a wide variety of physics topics. Among them is a detailed study of the weak interaction. An overview of studies of the hadronic weak (quark-quark) as well as semi-leptonic (quark-lepton) interactions at the Spallation Neutron Source (SNS) is presented. These measurements, done in few-nucleon systems, are finally letting us gain knowledge of the hadronic weak interaction without the contributions from nuclear effects. Forthcoming results from the NPDGamma experiment will, due to the simplicity of the neutron, provide an unambiguous measurement of the long range pion-nucleon weak coupling (often referred to as hπ), which will finally test the theoretical predictions. Results from NPDGamma and future results from the n +3 He experiment will need to be complemented by additional measurements to completely describe the hadronic weak interaction.

  2. Experimental noiseless linear amplification using weak measurements

    NASA Astrophysics Data System (ADS)

    Ho, Joseph; Boston, Allen; Palsson, Matthew; Pryde, Geoff

    2016-09-01

    The viability of quantum communication schemes rely on sending quantum states of light over long distances. However, transmission loss can degrade the signal strength, adding noise. Heralded noiseless amplification of a quantum signal can provide a solution by enabling longer direct transmission distances and by enabling entanglement distillation. The central idea of heralded noiseless amplification—a conditional modification of the probability distribution over photon number of an optical quantum state—is suggestive of a parallel with weak measurement: in a weak measurement, learning partial information about an observable leads to a conditional back-action of a commensurate size. Here we experimentally investigate the application of weak, or variable-strength, measurements to the task of heralded amplification, by using a quantum logic gate to weakly couple a small single-optical-mode quantum state (the signal) to an ancilla photon (the meter). The weak measurement is carried out by choosing the measurement basis of the meter photon and, by conditioning on the meter outcomes, the signal is amplified. We characterise the gain of the amplifier as a function of the measurement strength, and use interferometric methods to show that the operation preserves the coherence of the signal.

  3. Explaining numeracy development in weak performing kindergartners.

    PubMed

    Toll, Sylke W M; Van Luit, Johannes E H

    2014-08-01

    Gaining better insight into precursors of early numeracy in young children is important, especially in those with inadequate numeracy skills. Therefore, in the current study, visual and verbal working memory, non-symbolic and symbolic comparison skills, and specific math-related language were used to explain early numeracy performance and development of weak performing children throughout kindergarten. The early numeracy ability of both weak performers and typical performers was measured at four time points during 2 years of kindergarten to compare growth rates. Results show a significant faster development of early numeracy in the weak performers. The development of weak performers' numeracy was influenced by verbal working memory, symbolic comparison skills, and math language, whereas only math language was positively related to the slope of typical performers' numeracy. In the weak performers, visual working memory, non-symbolic comparison skills, and math language showed an effect on the initial early numeracy level of these children. The intercept of the typical performers was predicted by five covariates, all except non-symbolic comparison. PMID:24786672

  4. DRAM Weak Cell Characterization for Retention Time.

    PubMed

    Kang, Jonghyuk; Lee, Sungho; Choi, Byoungdeog

    2016-05-01

    This work proposes a sequence of tests for detecting refresh weak cells based on data retention time distribution in the main cell array of DRAMs and verify the feasibility of the proposed method through analysis of 30 nm design-rule DRAM cells with Recess Channel Array Transistor (RCAT) and Buried Channel Array Transistor (BCAT). Basic idea of the proposed mechanism is to test with different bias conditions and break down retention failures based on their root causes such as Gate Induced Drain Leakage, sub-threshold leakage and junction leakage. This categorization helps to determine the physical locations of each failure group, enabling precise Physical Failure Analysis (PFA). The characterization of data retention weak cells for 30 nm design rule DRAMs with BCAT and RCAT has been investigated. Most weak cells were classified as GIDL leaky cells in both cases. In the case of BCAT, the distance between the word line and the storage node, caused by the process distribution, is the main origin of weak cells. In the case of RCAT, the sharp corner of the active layer in the storage node is the main cause of weak cells. PMID:27483878

  5. Functional impact of sarcopenia in respiratory muscles

    PubMed Central

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

    2016-01-01

    The risk for respiratory complications and infections is substantially increased in old age, which may be due, in part, to sarcopenia (aging-related weakness and atrophy) of the diaphragm muscle (DIAm), reducing its force generating capacity and impairing the ability to perform expulsive non-ventilatory motor behaviors critical for airway clearance. The aging-related reduction in DIAm force generating capacity is due to selective atrophy of higher force generating type IIx and/or IIb muscle fibers, whereas lower force generating type I and IIa muscle fiber sizes are preserved. Fiber type specific DIAm atrophy is also seen following unilateral phrenic nerve denervation and in other neurodegenerative disorders. Accordingly, the effect of aging on DIAm function resembles that of neurodegeneration and suggests possible common mechanisms, such as the involvement of several neurotrophic factors in mediating DIAm sarcopenia. This review will focus on changes in two neurotrophic signaling pathways that represent potential mechanisms underlying the aging-related fiber type specific DIAm atrophy. PMID:26467183

  6. Muscle wasting in cancer.

    PubMed

    Johns, N; Stephens, N A; Fearon, K C H

    2013-10-01

    Skeletal muscle loss appears to be the most significant clinical event in cancer cachexia and is associated with a poor outcome. With regard to such muscle loss, despite extensive study in a range of models, there is ongoing debate as to whether a reduction in protein synthesis, an increase in degradation or a combination of both is the more relevant. Each model differs in terms of key mediators and the pathways activated in skeletal muscle. Certain models do suggest that decreased synthesis accompanied by enhanced protein degradation via the ubiquitin proteasome pathway (UPP) is important. Murine models tend to involve rapid development of cachexia and may represent more acute muscle atrophy rather than the chronic wasting observed in humans. There is a paucity of human data both at a basic descriptive level and at a molecular/mechanism level. Progress in treating the human form of cancer cachexia can only move forwards through carefully designed large randomised controlled clinical trials of specific therapies with validated biomarkers of relevance to underlying mechanisms. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.

  7. Muscle Injuries in Athletes

    PubMed Central

    Delos, Demetris; Maak, Travis G.; Rodeo, Scott A.

    2013-01-01

    Context: Muscle injuries are extremely common in athletes and often produce pain, dysfunction, and the inability to return to practice or competition. Appropriate diagnosis and management can optimize recovery and minimize time to return to play. Evidence Acquisition: Contemporary papers, both basic science and clinical medicine, that investigate muscle healing were reviewed. A Medline/PubMed search inclusive of years 1948 to 2012 was performed. Results: Diagnosis can usually be made according to history and physical examination for most injuries. Although data are limited, initial conservative management emphasizing the RICE principles and immobilization of the extremity for several days for higher grade injuries are typically all that is required. Injection of corticosteroids may clinically enhance function after an acute muscle strain. Additional adjunctive treatments (nonsteroidal anti-inflammatory drugs, platelet-rich plasma, and others) to enhance muscle healing and limit scar formation show promise but need additional data to better define their roles. Conclusion: Conservative treatment recommendations will typically lead to successful outcomes after a muscle injury. There is limited evidence to support most adjunctive treatments. PMID:24459552

  8. Positronium Formation in Muscle

    PubMed Central

    Gustafson, D. R.

    1970-01-01

    Positronium formation in muscle at +4°C and -4°C was examined by the measurement of the angular correlation of positron annihilation radiation. Since the positronium formation rate in ice is considerably higher than it is in water, there should be a comparable increase in the positronium formation rate in muscle tissue if recent speculation that cellular water is ordered in a semicrystalline icelike state is correct. Comparison of the angular correlation from muscle at +4°C with that from water at +4°C shows no enhancement of the positronium formation rate. Frozen muscle at -4°C shows an enhancement of the positronium formation rate of approximately half that found in ice at -4°C, indicating that most cellular water undergoes a normal water-ice transition when frozen. It is concluded therefore that cell water in muscle is not ordered in a hexagonal icelike structure. While the results are consistent with the hypothesis that cell water is in the liquid state, the hypothesis that cell water is ordered in an undetermined close packed structure which transforms to the hexagonal ice structure at or near 0°C cannot be ruled out. PMID:5436881

  9. Effect of L-carnitine on fatty acid oxidation of the muscle in hemodialysis patients

    SciTech Connect

    Siami, G.; Clinton, M.; Borum, P.

    1986-03-05

    Muscle weakness is a major cause of morbidity in end stage renal disease (ESRD) patients on long term hemodialysis (HD). Carnitine (C) is important for transport of fatty acids into mitochondria. The kidney is a major site of C biosynthesis which may be compromised in ESRD. C is lost during dialysis and is reduced in plasma and muscle. Although the cause of muscle weakness is multifactorial, the effect of supplemental C was tested on a group of ESRD patients on HD. C (1 gm I.V. 3 x/wk) or placebo was given to HD patients for 6 months. Muscle biopsies were obtained before and after C supplementation and from control subjects. Muscle pathology was examined by histochemical light microscopy. Fatty acid oxidation (FAO) by homogenate of the biopsied muscle was measured using (/sup 14/C) palmitate. Plasma aluminum (AL) and parthyroid hormone (PTH) were also measured and patients were evaluated for the degree of muscle weakness. All Pts had abnormal muscle pathology and C supplementation did not improve it. FAO by 3 HD Pts who had received placebo was 639 +/- 285 (S.D.) dpm/mg protein while control subjects were 1487 +/- 267 and was statistically different (p < .003). FAO by 8 HD Pts receiving C was not different from placebo. Addition of C in vitro stimulated FAO 70 to 80%, but there was not difference between groups. The degree of FAO was inversely correlated with the severity of the muscle pathology, and was directly correlated with the concentration of C in muscle. Pts with high plasma AL had lower FAO, but there was no correlation between FAO and PTH.

  10. Prostaglandin synthetase and prostacyclin synthetase in mature rat skeletal muscles: immunohistochemical localisation to arterioles, tendons and connective tissues.

    PubMed Central

    McLennan, I S; Macdonald, R E

    1991-01-01

    Mature skeletal muscles produce appreciable quantities of prostacyclin (PGI2) and smaller amounts of PGF2 alpha and PGE2, but the sources of these prostaglandins within skeletal muscle are unknown. Monoclonal antibodies to prostaglandin synthetase and prostacyclin synthetase were used to determine which muscle cells produce prostaglandins. The antibody to prostacyclin synthetase stained the tendon, fascia, epimysium and the arteries leading to the muscles. The endothelia of arterioles were also stained in the tibialis anterior and cremaster but not in the soleus muscles. Only trace levels of immunoreactivity were observed with the antibody to prostaglandin synthetase in normal muscles. However, immunoreactivity was observed in the muscles of rats that had been pretreated with aspirin, a drug that inhibits and stabilises prostaglandin synthetase. In muscles of the aspirin-treated rats, all cell types that were stained by the antiprostacyclin synthetase also reacted weakly with the antibody to prostaglandin synthetase. In addition, some cells in the endomysium were strongly stained with the antiprostaglandin synthetase but not with the antiprostacyclin synthetase. We conclude that (1) at least one aspect of the regulation of blood flow in the microcirculation of slow muscles is different from that of fast muscles, (2) that the tendon and connective tissue is the major source of PGI2 in mature skeletal muscles, and (3) that the prostaglandin-dependent effects of insulin and some other stimuli on skeletal muscle may be mediated by the muscle's arterioles or connective tissue. Images Fig. 1 Fig. 2 Fig. 3 PMID:1810931

  11. Hyperglycemia-induced diaphragm weakness is mediated by oxidative stress

    PubMed Central

    2014-01-01

    Introduction A major consequence of ICU-acquired weakness (ICUAW) is diaphragm weakness, which prolongs the duration of mechanical ventilation. Hyperglycemia (HG) is a risk factor for ICUAW. However, the mechanisms underlying HG-induced respiratory muscle weakness are not known. Excessive reactive oxygen species (ROS) injure multiple tissues during HG, but only one study suggests that excessive ROS generation may be linked to HG-induced diaphragm weakness. We hypothesized that HG-induced diaphragm dysfunction is mediated by excessive superoxide generation and that administration of a specific superoxide scavenger, polyethylene glycol superoxide dismutase (PEG-SOD), would ameliorate these effects. Methods HG was induced in rats using streptozotocin (60 mg/kg intravenously) and the following groups assessed at two weeks: controls, HG, HG + PEG-SOD (2,000U/kg/d intraperitoneally for seven days), and HG + denatured (dn)PEG-SOD (2000U/kg/d intraperitoneally for seven days). PEG-SOD and dnPEG-SOD were administered on day 8, we measured diaphragm specific force generation in muscle strips, force-pCa relationships in single permeabilized fibers, contractile protein content and indices of oxidative stress. Results HG reduced diaphragm specific force generation, altered single fiber force-pCa relationships, depleted troponin T, and increased oxidative stress. PEG-SOD prevented HG-induced reductions in diaphragm specific force generation (for example 80 Hz force was 26.4 ± 0.9, 15.4 ± 0.9, 24.0 ± 1.5 and 14.9 ± 0.9 N/cm2 for control, HG, HG + PEG-SOD, and HG + dnPEG-SOD groups, respectively, P <0.001). PEG-SOD also restored HG-induced reductions in diaphragm single fiber force generation (for example, Fmax was 182.9 ± 1.8, 85.7 ± 2.0, 148.6 ± 2.4 and 90.9 ± 1.5 kPa in control, HG, HG + PEG-SOD, and HG + dnPEG-SOD groups, respectively, P <0.001). HG-induced troponin T depletion, protein nitrotyrosine formation

  12. A Beetle Flight Muscle Displays Leg Muscle Microstructure.

    PubMed

    Shimomura, Toshiki; Iwamoto, Hiroyuki; Vo Doan, Tat Thang; Ishiwata, Shin'ichi; Sato, Hirotaka; Suzuki, Madoka

    2016-09-20

    In contrast to major flight muscles in the Mecynorrhina torquata beetle, the third axillary (3Ax) muscle is a minor flight muscle that uniquely displays a powerful mechanical function despite its considerably small volume, ∼1/50 that of a major flight muscle. The 3Ax muscle contracts relatively slowly, and in flight strongly pulls the beating wing to attenuate the stroke amplitude. This attenuation leads to left-right turning in flight or wing folding to cease flying. What enables this small muscle to be so powerful? To explore this question, we examined the microstructure of the 3Ax muscle using synchrotron x-ray diffraction, optical microscopy, and immunoblotting analysis. We found that the 3Ax muscle has long (∼5 μm) myofilaments and that the ratio of thick (myosin) filaments to thin (actin) filaments is 1:5 or 1:6. These characteristics are not observed in the major flight muscles, which have shorter myofilaments (∼3.5 μm) with a smaller ratio (1:3), and instead are more typical of a leg muscle. Furthermore, the flight-muscle-specific troponin isoform, TnH, is not expressed in the 3Ax muscle. Since such a microstructure is suitable for generating large tension, the 3Ax muscle is appropriately designed to pull the wing strongly despite its small volume. PMID:27653488

  13. A Beetle Flight Muscle Displays Leg Muscle Microstructure.

    PubMed

    Shimomura, Toshiki; Iwamoto, Hiroyuki; Vo Doan, Tat Thang; Ishiwata, Shin'ichi; Sato, Hirotaka; Suzuki, Madoka

    2016-09-20

    In contrast to major flight muscles in the Mecynorrhina torquata beetle, the third axillary (3Ax) muscle is a minor flight muscle that uniquely displays a powerful mechanical function despite its considerably small volume, ∼1/50 that of a major flight muscle. The 3Ax muscle contracts relatively slowly, and in flight strongly pulls the beating wing to attenuate the stroke amplitude. This attenuation leads to left-right turning in flight or wing folding to cease flying. What enables this small muscle to be so powerful? To explore this question, we examined the microstructure of the 3Ax muscle using synchrotron x-ray diffraction, optical microscopy, and immunoblotting analysis. We found that the 3Ax muscle has long (∼5 μm) myofilaments and that the ratio of thick (myosin) filaments to thin (actin) filaments is 1:5 or 1:6. These characteristics are not observed in the major flight muscles, which have shorter myofilaments (∼3.5 μm) with a smaller ratio (1:3), and instead are more typical of a leg muscle. Furthermore, the flight-muscle-specific troponin isoform, TnH, is not expressed in the 3Ax muscle. Since such a microstructure is suitable for generating large tension, the 3Ax muscle is appropriately designed to pull the wing strongly despite its small volume.

  14. Weak lensing in the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Troxel, Michael

    2016-03-01

    I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.

  15. Composition of weakly altered Martian crust

    NASA Technical Reports Server (NTRS)

    Mustard, J. F.; Murchie, S. L.; Erard, S.

    1993-01-01

    The mineralogic and chemical composition of weakly altered crust remains an unresolved question for Mars. Dark regions hold clues to the composition since they are thought to comprise surface exposures of weakly altered crustal materials. Understanding the in situ composition of relatively pristine crustal rocks in greater detail is important for investigating basic volcanic processes. Also, this will provide additional constraints on the chemical pathways by which pristine rocks are altered to produce the observed ferric iron-bearing assemblages and inferred clay silicate, sulphate, and magnetic oxide phases. Reflectance spectra of dark regions obtained with the ISM instrument are being used to determine the basic mineralogy of weakly altered crust for a variety of regions on Mars.

  16. Weak self-adjoint differential equations

    NASA Astrophysics Data System (ADS)

    Gandarias, M. L.

    2011-07-01

    The concepts of self-adjoint and quasi self-adjoint equations were introduced by Ibragimov (2006 J. Math. Anal. Appl. 318 742-57 2007 Arch. ALGA 4 55-60). In Ibragimov (2007 J. Math. Anal. Appl. 333 311-28), a general theorem on conservation laws was proved. In this paper, we generalize the concept of self-adjoint and quasi self-adjoint equations by introducing the definition of weak self-adjoint equations. We find a class of weak self-adjoint quasi-linear parabolic equations. The property of a differential equation to be weak self-adjoint is important for constructing conservation laws associated with symmetries of the differential equation.

  17. Weak Acid Ionization Constants and the Determination of Weak Acid-Weak Base Reaction Equilibrium Constants in the General Chemistry Laboratory

    ERIC Educational Resources Information Center

    Nyasulu, Frazier; McMills, Lauren; Barlag, Rebecca

    2013-01-01

    A laboratory to determine the equilibrium constants of weak acid negative weak base reactions is described. The equilibrium constants of component reactions when multiplied together equal the numerical value of the equilibrium constant of the summative reaction. The component reactions are weak acid ionization reactions, weak base hydrolysis…

  18. [MUSCLE WEAKNESS WITH NO SIGNS OF POLYNEUROPATHY IN PATIENTS WITH PROLONGED DISTURBANCE OF CONSCIOUSNESS. CASE REPORT].

    PubMed

    Kondrat'eva, E A; Kondrat'ev, S A; Ivanova, N E

    2016-01-01

    Paper present several clinical examples of prolonged tetraplegia, which could be outcome not only of polyneuromyopathy of critical states, but also of disturbances in hierarchical relationship in CNS. PMID:27468509

  19. Extrapolating Weak Selection in Evolutionary Games

    PubMed Central

    Wu, Bin; García, Julián; Hauert, Christoph; Traulsen, Arne

    2013-01-01

    In evolutionary games, reproductive success is determined by payoffs. Weak selection means that even large differences in game outcomes translate into small fitness differences. Many results have been derived using weak selection approximations, in which perturbation analysis facilitates the derivation of analytical results. Here, we ask whether results derived under weak selection are also qualitatively valid for intermediate and strong selection. By “qualitatively valid” we mean that the ranking of strategies induced by an evolutionary process does not change when the intensity of selection increases. For two-strategy games, we show that the ranking obtained under weak selection cannot be carried over to higher selection intensity if the number of players exceeds two. For games with three (or more) strategies, previous examples for multiplayer games have shown that the ranking of strategies can change with the intensity of selection. In particular, rank changes imply that the most abundant strategy at one intensity of selection can become the least abundant for another. We show that this applies already to pairwise interactions for a broad class of evolutionary processes. Even when both weak and strong selection limits lead to consistent predictions, rank changes can occur for intermediate intensities of selection. To analyze how common such games are, we show numerically that for randomly drawn two-player games with three or more strategies, rank changes frequently occur and their likelihood increases rapidly with the number of strategies . In particular, rank changes are almost certain for , which jeopardizes the predictive power of results derived for weak selection. PMID:24339769

  20. Classification and grading of muscle injuries: a narrative review

    PubMed Central

    Hamilton, Bruce; Valle, Xavier; Rodas, Gil; Til, Luis; Grive, Ricard Pruna; Rincon, Josep Antoni Gutierrez; Tol, Johannes L

    2015-01-01

    A limitation to the accurate study of muscle injuries and their management has been the lack of a uniform approach to the categorisation and grading of muscle injuries. The goal of this narrative review was to provide a framework from which to understand the historical progression of the classification and grading of muscle injuries. We reviewed the classification and grading of muscle injuries in the literature to critically illustrate the strengths, weaknesses, contradictions or controversies. A retrospective, citation-based methodology was applied to search for English language literature which evaluated or utilised a novel muscle classification or grading system. While there is an abundance of literature classifying and grading muscle injuries, it is predominantly expert opinion, and there remains little evidence relating any of the clinical or radiological features to an established pathology or clinical outcome. While the categorical grading of injury severity may have been a reasonable solution to a clinical challenge identified in the middle of the 20th century, it is time to recognise the complexity of the injury, cease trying to oversimplify it and to develop appropriately powered research projects to answer important questions. PMID:25394420

  1. Muscle degeneration without mechanical injury in sarcoglycan deficiency.

    PubMed

    Hack, A A; Cordier, L; Shoturma, D I; Lam, M Y; Sweeney, H L; McNally, E M

    1999-09-14

    In humans, mutations in the genes encoding components of the dystrophin-glycoprotein complex cause muscular dystrophy. Specifically, primary mutations in the genes encoding alpha-, beta-, gamma-, and delta-sarcoglycan have been identified in humans with limb-girdle muscular dystrophy. Mice lacking gamma-sarcoglycan develop progressive muscular dystrophy similar to human muscular dystrophy. Without gamma-sarcoglycan, beta- and delta-sarcoglycan are unstable at the muscle membrane and alpha-sarcoglycan is severely reduced. The expression and localization of dystrophin, dystroglycan, and laminin-alpha2, a mechanical link between the actin cytoskeleton and the extracellular matrix, appears unaffected by the loss of sarcoglycan. We assessed the functional integrity of this mechanical link and found that isolated muscles lacking gamma-sarcoglycan showed normal resistance to mechanical strain induced by eccentric muscle contraction. Sarcoglycan-deficient muscles also showed normal peak isometric and tetanic force generation. Furthermore, there was no evidence for contraction-induced injury in mice lacking gamma-sarcoglycan that were subjected to an extended, rigorous exercise regimen. These data demonstrate that mechanical weakness and contraction-induced muscle injury are not required for muscle degeneration and the dystrophic process. Thus, a nonmechanical mechanism, perhaps involving some unknown signaling function, likely is responsible for muscular dystrophy where sarcoglycan is deficient.

  2. Sarcocystis fayeri in skeletal muscle of horses with neuromuscular disease.

    PubMed

    Aleman, Monica; Shapiro, Karen; Sisó, Silvia; Williams, Diane C; Rejmanek, Daniel; Aguilar, Beatriz; Conrad, Patricia A

    2016-01-01

    Recent reports of Sarcocystis fayeri-induced toxicity in people consuming horse meat warrant investigation on the prevalence and molecular characterization of Sarcocystis spp. infection in horses. Sarcocysts in skeletal muscle of horses have been commonly regarded as an incidental finding. In this study, we investigated the prevalence of sarcocysts in skeletal muscle of horses with neuromuscular disease. Our findings indicated that S. fayeri infection was common in young mature horses with neuromuscular disease and could be associated with myopathic and neurogenic processes. The number of infected muscles and number of sarcocysts per muscle were significantly higher in diseased than in control horses. S. fayeri was predominantly found in low oxidative highly glycolytic myofibers. This pathogen had a high glycolytic metabolism. Common clinical signs of disease included muscle atrophy, weakness with or without apparent muscle pain, gait deficits, and dysphagia in horses with involvement of the tongue and esophagus. Horses with myositis were lethargic, apparently painful, stiff, and reluctant to move. Similar to humans, sarcocystosis and cardiomyopathy can occur in horses. This study did not establish causality but supported a possible association (8.9% of cases) with disease. The assumption of Sarcocysts spp. being an incidental finding in every case might be inaccurate.

  3. Skeletal muscle disorders associated with selenium deficiency in humans.

    PubMed

    Chariot, Patrick; Bignani, Olivier

    2003-06-01

    Skeletal muscle disorders manifested by muscle pain, fatigue, proximal weakness, and serum creatine kinase (CK) elevation have been reported in patients with selenium deficiency. The object of this report was to review the conditions in which selenium deficiency is associated with human skeletal muscle disorders and to evaluate the importance of mitochondrial alterations in these disorders. A systematic literature review using the Medline database and Cochrane Library provided 38 relevant articles. The main conditions associated with selenium deficiency fell into three categories: (1) insufficient selenium intake in low soil-selenium areas; (2) parenteral or enteral nutrition, or malabsorption; and (3) chronic conditions associated with oxidative stress, such as chronic alcohol abuse and human immunodeficiency virus (HIV) infection. In low soil-selenium areas, reversibility of muscle symptoms was similar after selenium supplementation and placebo administration, suggesting a role for other factors in the development of disease. In parenteral or enteral nutrition, or malabsorption, muscle symptoms improved after selenium supplementation in 18 of 19 patients (median delay: 4 weeks). The reason that only a minority of selenium-deficient patients present with skeletal muscle disorders is unclear and is possibly related to cofactors, such as viral infections and drugs. Prospective studies of selenium-deficient myopathies would be useful in critically ill patients, alcohol abusers, and HIV-infected patients. PMID:12766976

  4. [A case of myokymia-hyperhidrosis syndrome with muscle involvement].

    PubMed

    Ono, S; Tomono, H; Maeda, Y; Shimizu, N; Shimizu, N

    1989-01-01

    The present report deals with an unique case of myokymia-hyperhidrosis syndrome. A 46-year-old man developed generalized relatively slow, undulating movement of the muscles, excessive sweating, muscle cramps and easy fatigability since three years ago. On admission, he had generalized myokymia, abnormal movements consisting of slow, undulating and worm-like muscular contractions. There was no muscle atrophy or weakness, or sensory deficits. Deep tendon reflexes were diminished and no Babinski sign or other pathological reflexes were present. Muscle tone was in normal range. Neither fasciculation nor myotonia was found. Laboratory examinations revealed elevation of BMR with normal thyroid function. The value of anti-Ach receptor antibody was below 0.6nmol/l. EMG recordings showed (1) continuous spontaneous repetitive discharges of NMU at a frequency of 30-50Hz, with duration of 1-2 seconds and amplitude of about 1 mV, were demonstrated at rest and the findings were consistent with myokymia, (2) waxing phenomenon was observed on repetitive peripheral nerve stimuli, which didn't improve by the tension test, and (3) high amplitude, long duration and polyphasic NMU, a sign of denervation, were observed on voluntary contraction. Muscle biopsy specimens from the left quadriceps showed a number of internal nuclei. On electron microscopy, clustered mitochondria and filamentous bodies were very often found in subsarcolemma. From these observations, damage to peripheral nerves, neuromuscular junctions and muscles may be responsible for the generalized myokymia in our patient. PMID:2743686

  5. Classification and grading of muscle injuries: a narrative review.

    PubMed

    Hamilton, Bruce; Valle, Xavier; Rodas, Gil; Til, Luis; Grive, Ricard Pruna; Rincon, Josep Antoni Gutierrez; Tol, Johannes L

    2015-03-01

    A limitation to the accurate study of muscle injuries and their management has been the lack of a uniform approach to the categorisation and grading of muscle injuries. The goal of this narrative review was to provide a framework from which to understand the historical progression of the classification and grading of muscle injuries. We reviewed the classification and grading of muscle injuries in the literature to critically illustrate the strengths, weaknesses, contradictions or controversies. A retrospective, citation-based methodology was applied to search for English language literature which evaluated or utilised a novel muscle classification or grading system. While there is an abundance of literature classifying and grading muscle injuries, it is predominantly expert opinion, and there remains little evidence relating any of the clinical or radiological features to an established pathology or clinical outcome. While the categorical grading of injury severity may have been a reasonable solution to a clinical challenge identified in the middle of the 20th century, it is time to recognise the complexity of the injury, cease trying to oversimplify it and to develop appropriately powered research projects to answer important questions.

  6. Proteasome dysfunction induces muscle growth defects and protein aggregation.

    PubMed

    Kitajima, Yasuo; Tashiro, Yoshitaka; Suzuki, Naoki; Warita, Hitoshi; Kato, Masaaki; Tateyama, Maki; Ando, Risa; Izumi, Rumiko; Yamazaki, Maya; Abe, Manabu; Sakimura, Kenji; Ito, Hidefumi; Urushitani, Makoto; Nagatomi, Ryoichi; Takahashi, Ryosuke; Aoki, Masashi

    2014-12-15

    The ubiquitin-proteasome and autophagy-lysosome pathways are the two major routes of protein and organelle clearance. The role of the proteasome pathway in mammalian muscle has not been examined in vivo. In this study, we report that the muscle-specific deletion of a crucial proteasomal gene, Rpt3 (also known as Psmc4), resulted in profound muscle growth defects and a decrease in force production in mice. Specifically, developing muscles in conditional Rpt3-knockout animals showed dysregulated proteasomal activity. The autophagy pathway was upregulated, but the process of autophagosome formation was impaired. A microscopic analysis revealed the accumulation of basophilic inclusions and disorganization of the sarcomeres in young adult mice. Our results suggest that appropriate proteasomal activity is important for muscle growth and for maintaining myofiber integrity in collaboration with autophagy pathways. The deletion of a component of the proteasome complex contributed to myofiber degeneration and weakness in muscle disorders that are characterized by the accumulation of abnormal inclusions.

  7. Artificial muscles on heat

    NASA Astrophysics Data System (ADS)

    McKay, Thomas G.; Shin, Dong Ki; Percy, Steven; Knight, Chris; McGarry, Scott; Anderson, Iain A.

    2014-03-01

    Many devices and processes produce low grade waste heat. Some of these include combustion engines, electrical circuits, biological processes and industrial processes. To harvest this heat energy thermoelectric devices, using the Seebeck effect, are commonly used. However, these devices have limitations in efficiency, and usable voltage. This paper investigates the viability of a Stirling engine coupled to an artificial muscle energy harvester to efficiently convert heat energy into electrical energy. The results present the testing of the prototype generator which produced 200 μW when operating at 75°C. Pathways for improved performance are discussed which include optimising the electronic control of the artificial muscle, adjusting the mechanical properties of the artificial muscle to work optimally with the remainder of the system, good sealing, and tuning the resonance of the displacer to minimise the power required to drive it.

  8. Signaling in muscle contraction.

    PubMed

    Kuo, Ivana Y; Ehrlich, Barbara E

    2015-02-02

    Signaling pathways regulate contraction of striated (skeletal and cardiac) and smooth muscle. Although these are similar, there are striking differences in the pathways that can be attributed to the distinct functional roles of the different muscle types. Muscles contract in response to depolarization, activation of G-protein-coupled receptors and other stimuli. The actomyosin fibers responsible for contraction require an increase in the cytosolic levels of calcium, which signaling pathways induce by promoting influx from extracellular sources or release from intracellular stores. Rises in cytosolic calcium stimulate numerous downstream calcium-dependent signaling pathways, which can also regulate contraction. Alterations to the signaling pathways that initiate and sustain contraction and relaxation occur as a consequence of exercise and pathophysiological conditions.

  9. Measurement of muscle strength with handheld dynamometer in Intensive Care Unit

    PubMed Central

    Samosawala, Nidhi R.; Vaishali, K.; Kalyana, B. Chakravarthy

    2016-01-01

    Background: Intensive Care Unit (ICU) acquired weakness is a common complication in critically ill patients affecting their prognosis. The handheld dynamometry is an objective method in detecting minimum muscle strength change, which has an impact on the physical function of ICU survivors. The minimal change in the force can be measured in units of weight such as pounds or kilograms. Aim of the Study: To detect the changes in peripheral muscle strength with handheld dynamometer in the early stage of ICU stay and to observe the progression of muscle weakness. Methodology: Three upper and three lower limb muscles force measured with handheld dynamometer during ICU stay. Data were analyzed using repeated measures ANOVA to detect changes in force generated by muscle on alternate days of ICU stay. Results: There was a reduction in peripheral muscle strength from day 3 to day 5 as well from day 5 to day 7 of ICU stay (P < 0.01). The average reduction in peripheral muscle strength was 11.8% during ICU stay. Conclusion: This study showed a progressive reduction in peripheral muscle strength as measured by handheld dynamometer during early period of ICU stay. PMID:26955213

  10. Contribution of oxidative stress to pathology in diaphragm and limb muscles with Duchenne muscular dystrophy.

    PubMed

    Kim, Jong-Hee; Kwak, Hyo-Bum; Thompson, LaDora V; Lawler, John M

    2013-02-01

    Duchenne muscular dystrophy (DMD) is a degenerative skeletal muscle disease that makes walking and breathing difficult. DMD is caused by an X-linked (Xp21) mutation in the dystrophin gene. Dystrophin is a scaffolding protein located in the sarcolemmal cytoskeleton, important in maintaining structural integrity and regulating muscle cell (muscle fiber) growth and repair. Dystrophin deficiency in mouse models (e.g., mdx mouse) destabilizes the interface between muscle fibers and the extracellular matrix, resulting in profound damage, inflammation, and weakness in diaphragm and limb muscles. While the link between dystrophin deficiency with inflammation and pathology is multi-factorial, elevated oxidative stress has been proposed as a central mediator. Unfortunately, the use of non-specific antioxidant scavengers in mouse and human studies has led to inconsistent results, obscuring our understanding of the importance of redox signaling in pathology of muscular dystrophy. However, recent studies with more mechanistic approaches in mdx mice suggest that NAD(P)H oxidase and nuclear factor-kappaB are important in amplifying dystrophin-deficient muscle pathology. Therefore, more targeted antioxidant therapeutics may ameliorate damage and weakness in human population, thus promoting better muscle function and quality of life. This review will focus upon the pathobiology of dystrophin deficiency in diaphragm and limb muscle primarily in mouse models, with a rationale for development of targeted therapeutic antioxidants in DMD patients.

  11. Electro-weak reactions for astrophysics

    SciTech Connect

    R. Schiavilla

    2000-06-01

    The status of ''ab initio'' microscopic calculations of the {sup 2}H(p,{gamma}){sup 3}He and {sup 3}He(p,e{sup +}{nu}{sub e}){sup 4}He reactions is reviewed. The methods used to generate accurate nuclear ground- and scattering-state wave functions, and to construct realistic electro-weak transition operators are described. The uncertainties in the theoretical predictions, particularly those relevant to the p-{sup 3}He weak capture, are discussed. For the dp radiative capture, the theoretical results are compared with the TUNL data in the energy range 0--100 keV.

  12. Spectroscopy of a weakly isolated horizon

    NASA Astrophysics Data System (ADS)

    Chen, Ge-Rui; Huang, Yong-Chang

    2016-06-01

    The spectroscopy of a weakly isolated horizon has been investigated. We obtain an equally spaced entropy spectrum with its quantum equal to the one given by Bekenstein (Phys Rev D 7:2333, 1973). We demonstrate that the quantization of entropy and area is a generic property of horizons which exists in a wide class of spacetimes admitting weakly isolated horizons. Our method based on the tunneling method also indicates that the entropy quantum of black hole horizons is closely related to Hawking temperature.

  13. Weak Lie symmetry and extended Lie algebra

    SciTech Connect

    Goenner, Hubert

    2013-04-15

    The concept of weak Lie motion (weak Lie symmetry) is introduced. Applications given exhibit a reduction of the usual symmetry, e.g., in the case of the rotation group. In this context, a particular generalization of Lie algebras is found ('extended Lie algebras') which turns out to be an involutive distribution or a simple example for a tangent Lie algebroid. Riemannian and Lorentz metrics can be introduced on such an algebroid through an extended Cartan-Killing form. Transformation groups from non-relativistic mechanics and quantum mechanics lead to such tangent Lie algebroids and to Lorentz geometries constructed on them (1-dimensional gravitational fields).

  14. Simple understanding of quantum weak values

    NASA Astrophysics Data System (ADS)

    Qin, Lupei; Feng, Wei; Li, Xin-Qi

    2016-02-01

    In this work we revisit the important and controversial concept of quantum weak values, aiming to provide a simplified understanding to its associated physics and the origin of anomaly. Taking the Stern-Gerlach setup as a working system, we base our analysis on an exact treatment in terms of quantum Bayesian approach. We also make particular connection with a very recent work, where the anomaly of the weak values was claimed from the pure statistics in association with “disturbance” and “post-selection”, rather than the unique quantum nature. Our analysis resolves the related controversies through a clear and quantitative way.

  15. Simple understanding of quantum weak values

    PubMed Central

    Qin, Lupei; Feng, Wei; Li, Xin-Qi

    2016-01-01

    In this work we revisit the important and controversial concept of quantum weak values, aiming to provide a simplified understanding to its associated physics and the origin of anomaly. Taking the Stern-Gerlach setup as a working system, we base our analysis on an exact treatment in terms of quantum Bayesian approach. We also make particular connection with a very recent work, where the anomaly of the weak values was claimed from the pure statistics in association with “disturbance” and “post-selection”, rather than the unique quantum nature. Our analysis resolves the related controversies through a clear and quantitative way. PMID:26838670

  16. Compressive wavefront sensing with weak values.

    PubMed

    Howland, Gregory A; Lum, Daniel J; Howell, John C

    2014-08-11

    We demonstrate a wavefront sensor that unites weak measurement and the compressive-sensing, single-pixel camera. Using a high-resolution spatial light modulator (SLM) as a variable waveplate, we weakly couple an optical field's transverse-position and polarization degrees of freedom. By placing random, binary patterns on the SLM, polarization serves as a meter for directly measuring random projections of the wavefront's real and imaginary components. Compressive-sensing optimization techniques can then recover the wavefront. We acquire high quality, 256 × 256 pixel images of the wavefront from only 10,000 projections. Photon-counting detectors give sub-picowatt sensitivity.

  17. Critical level statistics for weakly disordered graphene.

    PubMed

    Amanatidis, E; Kleftogiannis, I; Katsanos, D E; Evangelou, S N

    2014-04-16

    In two dimensions chaotic level statistics with the Wigner spacing distribution P(S) is expected for massless fermions in the Dirac region. The obtained P(S) for weakly disordered finite graphene samples with zigzag edges turns out, however, to be neither chaotic (Wigner) nor localized (Poisson). It is similar to the intermediate statistics at the critical point of the Anderson metal-insulator tran