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https://www.readbyqxmd.com/read/28444436/acute-effects-of-static-stretching-on-muscle-tendon-mechanics-of-quadriceps-and-plantar-flexor-muscles
#1
Tom Bouvier, Jules Opplert, Carole Cometti, Nicolas Babault
PURPOSE: This study aimed to determine the acute effects of static stretching on stiffness indexes of two muscle groups with a contrasting difference in muscle-tendon proportion. METHODS: Eleven active males were tested on an isokinetic dynamometer during four sessions randomly presented. Two sessions were dedicated to quadriceps and the two others to triceps surae muscles. Before and immediately after the stretching procedure (5 × 30 s), gastrocnemius medialis and rectus femoris fascicle length and myotendinous junction elongation were determined using ultrasonography...
April 25, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28442075/passive-stiffness-of-the-ankle-and-plantar-flexor-muscle-performance-after-achilles-tendon-repair-a-cross-sectional-study
#2
Pollyana R T Borges, Thiago R T Santos, Paula R S Procópio, Jessica H D Chelidonopoulos, Roberto Zambelli, Juliana M Ocarino
BACKGROUND: Deficits in ankle muscle strength and ankle stiffness may be present in those subjects who underwent surgical treatment for an Achilles tendon rupture. The presence of these long-term deficits may contribute to a lower performance during daily activities and may be linked to future injuries. OBJECTIVE: To compare the ankle passive stiffness and the plantar flexor muscle performance in patients who underwent unilateral surgical treatment of Achilles tendon rupture with nonsurgical subjects...
January 2017: Brazilian Journal of Physical Therapy
https://www.readbyqxmd.com/read/28440369/a-variable-stiffness-dielectric-elastomer-actuator-based-on-electrostatic-chucking
#3
Hiroya Imamura, Kevin Kadooka, Minoru Taya
Dielectric elastomer actuators (DEA) are one type of promising artificial muscle; however, applications of bending-type DEA for robotic end-effectors may be limited by their low stiffness and ability to resist external loads without buckling. Unimorph DEA can produce large out-of-plane deformation suitable for use as robotic end effectors; however, design of such actuators for large displacement comes at the cost of low stiffness and blocking force. This work proposes and demonstrates a variable stiffness dielectric elastomer actuator (VSDEA) consisting of a plurality of unimorph DEA units operating in parallel, which can exhibit variable electrostatic chucking to modulate the structure's bending stiffness...
April 25, 2017: Soft Matter
https://www.readbyqxmd.com/read/28439516/engineering-muscle-networks-in-3d-gelatin-methacryloyl-hydrogels-influence-of-mechanical-stiffness-and-geometrical-confinement
#4
Marco Costantini, Stefano Testa, Ersilia Fornetti, Andrea Barbetta, Marcella Trombetta, Stefano Maria Cannata, Cesare Gargioli, Alberto Rainer
In this work, the influence of mechanical stiffness and geometrical confinement on the 3D culture of myoblast-laden gelatin methacryloyl (GelMA) photo-crosslinkable hydrogels was evaluated in terms of in vitro myogenesis. We formulated a set of cell-laden GelMA hydrogels with a compressive modulus in the range 1 ÷ 17 kPa, obtained by varying GelMA concentration and degree of cross-linking. C2C12 myoblasts were chosen as the cell model to investigate the supportiveness of different GelMA hydrogels toward myotube formation up to 2 weeks...
2017: Frontiers in Bioengineering and Biotechnology
https://www.readbyqxmd.com/read/28438465/isaacs-syndrome-with-caspr2-antibody-a-series-of-three-cases
#5
Jie Song, Sisi Jing, Chao Quan, Jun Lu, Xiangyang Qiao, Kai Qiao, Jiahong Lu, Jianying Xi, Chongbo Zhao
Isaacs syndrome is a form of peripheral nerve hyperexcitability, characterized by spontaneous muscle twitching and stiffness. Some patients are reported to be positive for CASPR2 antibody that may be one of the pathogenic autoantibodies in Isaacs syndrome. We reported a series of three patients with Isaacs syndrome, including their clinical features, electrophysiologic findings, laboratory parameters and therapeutic responses. All the three patients were positive for CASPR2 antibodies examined on transfected human embryonic kidney 293 cells by indirect immunofluorescence method...
April 21, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/28436534/a-novel-trpa1-variant-is-associated-with-carbamazepine-responsive-cramp-fasciculation-syndrome
#6
M J Nirenberg, R Chaouni, T M Biller, R M Gilbert, C Paisán-Ruiz
Cramp-fasciculation syndrome (CFS) is a rare muscle hyperexcitability syndrome that presents with muscle cramps, fasciculations, and stiffness, as well as pain, fatigue, anxiety, hyperreflexia, and paresthesias. Although familial cases have been reported, a genetic etiology has not yet been identified. We performed whole-exome sequencing followed by validation and cosegregation analyses on a father-son pair with CFS. Both subjects manifested other hypersensitivity-hyperexcitability symptoms, including asthma, gastroesophageal reflux, migraine, restless legs syndrome, tremor, cold hyperalgesia, and cardiac conduction defects...
April 24, 2017: Clinical Genetics
https://www.readbyqxmd.com/read/28435079/polyurethane-acrylates-as-effective-substrates-for-sustained-in-vitro-culture-of-human-myotubes
#7
Yosephine Andriani, Jason Chua Min-Wen, Benjamin Chua Yan-Jiang, Phang In Yee, Ng Shyh-Chang, Tan Wui Siew
Muscular disease has debilitating effects with severe damage leading to death. Our knowledge of muscle biology, disease and treatment is largely derived from non human cell models, even though non human cells are known to differ from human cells in their biochemical responses. Attempts to develop highly sought after in vitro human cell models have been plagued by early cell delamination and difficulties in achieving human myotube culture in vitro. In this work, we developed polyurethane acrylate (PUA) materials to support long term in vitro culture of human skeletal muscle tissue...
April 20, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28432448/resistance-to-radial-expansion-limits-muscle-strain-and-work
#8
E Azizi, A R Deslauriers, N C Holt, C E Eaton
The collagenous extracellular matrix (ECM) of skeletal muscle functions to transmit force, protect sensitive structures, and generate passive tension to resist stretch. The mechanical properties of the ECM change with age, atrophy, and neuromuscular pathologies, resulting in an increase in the relative amount of collagen and an increase in stiffness. Although numerous studies have focused on the effect of muscle fibrosis on passive muscle stiffness, few have examined how these structural changes may compromise contractile performance...
April 21, 2017: Biomechanics and Modeling in Mechanobiology
https://www.readbyqxmd.com/read/28431748/a-benchtop-biorobotic-platform-for-in-vitro-observation-of-muscle-tendon-dynamics-with-parallel-mechanical-assistance-from-an-elastic-exoskeleton
#9
Benjamin D Robertson, Siddarth Vadakkeveedu, Gregory S Sawicki
We present a novel biorobotic framework comprised of a biological muscle-tendon unit (MTU) mechanically coupled to a feedback controlled robotic environment simulation that mimics in vivo inertial/gravitational loading and mechanical assistance from a parallel elastic exoskeleton. Using this system, we applied select combinations of biological muscle activation (modulated with rate-coded direct neural stimulation) and parallel elastic assistance (applied via closed-loop mechanical environment simulation) hypothesized to mimic human behavior based on previously published modeling studies...
March 21, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28428826/the-reliability-of-shear-elastic-modulus-measurement-of-the-ankle-plantar-flexion-muscles-is-higher-at-dorsiflexed-position-of-the-ankle
#10
Junya Saeki, Tome Ikezoe, Masatoshi Nakamura, Satoru Nishishita, Noriaki Ichihashi
BACKGROUND: Excessive stiffness of lower limb muscles is associated with sports injuries. Therefore, the identification of a reliable measurement of the shear elastic modulus of various ankle plantar flexion muscles is required to evaluate lower leg sports injuries. This study investigated the reliable measurement of the shear elastic modulus of the ankle plantar flexion muscles at different ankle positions. METHODS: Twenty-three healthy young men (25.3 ± 3...
2017: Journal of Foot and Ankle Research
https://www.readbyqxmd.com/read/28427807/targeted-next-generation-sequencing-in-patients-with-myotonia-congenita
#11
Valentina Ferradini, Marco Cassone, Sara Nuovo, Ilaria Bagni, Rosaria D'Apice, Annalisa Botta, Giuseppe Novelli, Federica Sangiuolo
INTRODUCTION: Myotonia Congenita (MC) is a nondystrophic skeletal muscle disease characterized by muscle stiffness, weakness, delayed skeletal relaxation and hypertrophic muscle. The disease can be inherited as dominant or recessive. More than 130 mutations in CLCN1 gene have been identified. MATERIALS AND METHODS: We analyzed the entire coding region and exon-intron boundaries of the CLCN1 gene in 40 MC patients. Samples already Sanger-sequenced were successively evaluated by Next Generation Sequencing (NGS), on Ion Torrent PGM...
April 17, 2017: Clinica Chimica Acta; International Journal of Clinical Chemistry
https://www.readbyqxmd.com/read/28427689/demographic-and-clinical-profile-of-multiple-sclerosis-in-kashmir-a-short-report
#12
Insha Zahoor, Ravouf Asimi, Ehtishamul Haq, Irfan Yousuf Wani
BACKGROUND: Multiple sclerosis (MS) is a chronic autoimmune and inflammatory disease of the central nervous system (CNS). There have been only few population/hospital based studies on MS in India, and at the same time there is no data on its profile in Kashmir. METHODS: A total of 41 MS patients diagnosed on the basis of 2010 Revised Mc Donald criteria were enrolled in this study from Kashmir region of India. Clinical, demographic, radiological and biochemical parameters were analyzed for most of the patients...
April 2017: Multiple Sclerosis and related Disorders
https://www.readbyqxmd.com/read/28425815/reliability-validity-and-precision-of-a-handheld-myometer-for-assessing-in-vivo-muscle-stiffness
#13
Steven M Zinder, Darin A Padua
No abstract text is available yet for this article.
January 2017: Journal of Sport Rehabilitation
https://www.readbyqxmd.com/read/28422623/knee-stiffness-and-viscosity-new-implementation-and-perspectives-in-prosthesis-development
#14
Klemen Bohinc, Nejc Vantur, Drago Torkar, Tomaž Lampe, Marija Hribernik, Miroljub Jakovljević
The pendulum test is a method applied to measure passive resistance of the knee. A new and simple pendulum test with instrumentation based on infrared camera was used to evaluate knee stiffness and viscosity on a female human cadaver. The stiffness and viscosity were calculated based on the kinetic data. During the measurements, the periarticular and intraarticular soft tissue of the knee was gradually removed to determine the stiffness and viscosity as a function of the tissue removal rate. The measurements showed that the removal of tissue around the joint reduces the damping of leg oscillation, and therefore decreases the stiffness and viscosity...
April 19, 2017: Bosnian Journal of Basic Medical Sciences
https://www.readbyqxmd.com/read/28418359/-a-rare-concurrence-of-polymyalgia-rheumatica-and-aa-amyloidosis
#15
S G Radenska-Lopovok, O N Kotenko, N F Frolova, A I Zagrebneva, E S Stolyarevich, E V Volodina, V I Chervinko, E V Kryukov, M L Zubkin
Polymyalgia rheumatica (PMR) is a rare chronic inflammatory disease. It predominantly affects the elderly. The disease has a slow onset, pain and stiffness in the muscles of the shoulder and pelvic girdle, fever, weight loss, and a high acute-phase inflammatory response. The disease is concurrent with giant cell arteritis in a quarter of cases, which allows some authors to consider them as two different manifestations of the same pathological process. The kidneys are rarely involved. This disease is rarely complicated by AA amyloidosis...
2017: Arkhiv Patologii
https://www.readbyqxmd.com/read/28411442/ankle-muscle-co-contractions-during-quiet-standing-are-associated-with-decreased-postural-steadiness-in-the-elderly
#16
Albert H Vette, Dimitry G Sayenko, Michael Jones, Masaki O Abe, Kimitaka Nakazawa, Kei Masani
It has been reported that the elderly use co-contraction of the tibialis anterior (TA) and plantarflexor muscles for longer duration during quiet standing than the young. However, the particular role of ankle muscle co-contractions in the elderly during quiet standing remains unclear. Therefore, the objective of this study was to investigate the association between ankle muscle co-contractions and postural steadiness during standing in the elderly. Twenty-seven young (27.2±4.5yrs) and twenty-three elderly (66...
April 5, 2017: Gait & Posture
https://www.readbyqxmd.com/read/28411233/vasculopathy-in-the-setting-of-cardiorenal-syndrome-the-roles-of-protein-bound-uremic-toxins
#17
Jingbin Guo, Lu Lu, Yue Hua, Kevin Huang, Ian Wang, Li Huang, Qiang Fu, Aihua Chen, Paul Chan, Huimin Fan, Zhong-Min Liu, Bing Hui Wang
Chronic kidney disease (CKD) often leads to and accelerates the progression of cardiovascular disease (CVD), whilst CVD also causes kidney dysfunction. This bidirectional interaction leads to the development of a complex syndrome known as cardiorenal syndrome (CRS). CRS not only involves both the heart and the kidney, but also the vascular system through a vast array of contributing factors. In addition to hemodynamic, neuro-hormonal, mechanical and biochemical factors, the non-dialyzable protein-bound uremic toxins (PBUTs) are also key contributing factors that have been demonstrated through in vitro, in vivo and clinical observations...
April 14, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28407305/female-striated-urogenital-sphincter-contraction-measured-by-shear-wave-elastography-during-pelvic-floor-muscle-activation-proof-of-concept-and-validation
#18
Rafeef Aljuraifani, Ryan E Stafford, François Hug, Paul W Hodges
AIMS: Investigation of the function of the striated urogenital sphincter (SUS) is challenging because it is difficult to access and requires invasive measures. Ultrasound shear wave elastography (SWE) is a non-invasive real-time technique used to estimate tissue stiffness. As muscle stiffness can be used as an estimate of muscle force, SWE provides an opportunity to study contraction of the peri-urethral musculature. Validation of SWE to study SUS during functional tasks, such as pelvic floor muscle contractions, is required prior to application in clinical populations...
April 13, 2017: Neurourology and Urodynamics
https://www.readbyqxmd.com/read/28402887/the-closed-state-of-the-thin-filament-is-not-occupied-in-fully-activated-skeletal-muscle
#19
Sergey Y Bershitsky, Natalia A Koubassova, Michael A Ferenczi, Galina V Kopylova, Theyencheri Narayanan, Andrey K Tsaturyan
Muscle contraction is powered by actin-myosin interaction controlled by Ca(2+) via the regulatory proteins troponin (Tn) and tropomyosin (Tpm), which are associated with actin filaments. Tpm forms coiled-coil dimers, which assemble into a helical strand that runs along the whole ∼1 μm length of a thin filament. In the absence of Ca(2+), Tn that is tightly bound to Tpm binds actin and holds the Tpm strand in the blocked, or B, state, where Tpm shields actin from the binding of myosin heads. Ca(2+) binding to Tn releases the Tpm from actin so that it moves azimuthally around the filament axis to a closed, or C, state, where actin is partially available for weak binding of myosin heads...
April 11, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28400883/rehabilitation-after-rotator-cuff-repair
#20
REVIEW
Ourania Nikolaidou, Stefania Migkou, Christos Karampalis
BACKGROUND: Rotator cuff tears are a very common condition that is often incapacitating. Whether non-surgical or surgical, successful management of rotator cuff disease is dependent on appropriate rehabilitation. If conservative management is insufficient, surgical repair is often indicated. Postsurgical outcomes for patients having had rotator cuff repair can be quite good. A successful outcome is much dependent on surgical technique as it is on rehabilitation. Numerous rehabilitation protocols for the management of rotator cuff disease are based primarily on clinical experience and expert opinion...
2017: Open Orthopaedics Journal
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