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https://www.readbyqxmd.com/read/28326563/early-structural-and-functional-signature-of-3-day-human-skeletal-muscle-disuse-using-the-dry-immersion-model
#1
Rémi Demangel, Loïc Treffel, Guillaume Py, Thomas Brioche, Allan F Pagano, Marie-Pierre Bareille, Arnaud Beck, Laurence Pessemesse, Robin Candau, Claude Gharib, Angèle Chopard, Catherine Millet
Microgravity and hypoactivity are associated with skeletal muscle deconditioning. The decrease of muscle mass is an exponential decay with major changes in the first days. The purpose of the study was to dissect out the effects of a short-term 3-day dry immersion (DI) on human quadriceps muscle function and structure. The DI model, by suppressing all support zones, accurately reproduces the effects of microgravity. Twelve healthy volunteers (32 ± 5 yrs) completed 3 days of DI. Muscle function was investigated through maximal voluntary contraction (MVC) tests and muscle viscoelasticity...
March 22, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28325641/spectrum-of-nondystrophic-skeletal-muscle-channelopathies-in-children
#2
Fouad Al-Ghamdi, Basil T Darras, Partha S Ghosh
BACKGROUND: The nondystrophic skeletal muscle channelopathies are a group of disorders caused by mutations of various voltage-gated ion channel genes, including nondystrophic myotonia and periodic paralysis. METHODS: We identified patients with a diagnosis of muscle channelopathy from our neuromuscular database in a tertiary care pediatric center from 2005 to 2015. We then performed a retrospective review of their medical records for demographic characteristics, clinical features, investigations, treatment, and follow-up...
February 16, 2017: Pediatric Neurology
https://www.readbyqxmd.com/read/28324974/altered-viscoelastic-properties-of-stroke-affected-muscles-estimated-using-ultrasound-shear-waves-preliminary-data
#3
Ghulam Rasool, Allison B Wang, William Z Rymer, Sabrina S M Lee
As a result of a brain injury such as stroke, the skeletal muscles may undergo numerous structural and functional alterations. These abnormal changes are linked to muscle weakness, joint contracture, and abnormal muscle tone and eventually, result in motor impairment. A subset of these alterations affects passive muscle stiffness, i.e., viscoelastic properties. However, in vivo estimation of changes in viscoelastic properties is a challenging task. Here, we used the shear wave velocity, estimated through ultrasound SuperSonic imaging (SSI), as a surrogate for viscoelastic properties...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28324973/force-controlled-ultrasound-to-measure-passive-mechanical-properties-of-muscle-in-duchenne-muscular-dystrophy
#4
Anne J Pigula, Jim S Wu, Matthew W Gilbertson, Basil T Darras, Seward B Rutkove, Brian W Anthony
The purpose of this study is to assess differences in skeletal muscle compressibility between patients with Duchenne muscular dystrophy (DMD) and normal subjects. The transverse passive mechanical properties of muscle, particularly those related to stiffness and elasticity, can be measured using force-controlled ultrasound. We acquired ultrasound videos of muscle compression under known pressures in the biceps and quadriceps in 23 boys with DMD and 20 age-matched healthy controls. We calculated the bulk linear spring constant, nonlinear stress-strain response, and average Young's modulus for each...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28315581/morphological-and-physiological-differences-in-the-upper-trapezius-muscle-in-patients-with-work-related-trapezius-myalgia-compared-to-healthy-controls-a-systematic-review
#5
REVIEW
Kayleigh De Meulemeester, Patrick Calders, Robby De Pauw, Ine Grymonpon, Anke Govaerts, Barbara Cagnie
BACKGROUND: Trapezius myalgia is a common musculoskeletal complaint, characterized by pain, stiffness and tightness of the upper trapezius muscle. It is often work-related and caused by prolonged static and repetitive work tasks. It is hypothesized that this leads to various morphological and physiological alterations in muscle tissue but the pathophysiology is poorly understood. These alterations can be investigated by analysing muscle biopsies in order to reveal the underlying cellular mechanisms...
March 6, 2017: Musculoskelet Sci Pract
https://www.readbyqxmd.com/read/28302869/motor-and-mechanical-bases-of-the-courtship-call-of-the-male-treehopper-umbonia-crassicornis
#6
Carol I Miles, Brianna E Allison, Michael J Losinger, Quang T Su, Ronald N Miles
This study is a physiological, anatomical, and biophysical analysis of how plant-borne vibrational signals are produced by the treehopper Umbonia crassicornis During courtship, males and females engage in a vibrational duet, with each producing a characteristic call. For males, this consists of a frequency-modulated tonal signal which is accompanied by rhythmic broad-band clicks. While previous studies described these complex signals in detail, little is known about how they are produced. By combining video recordings, electromyograms, dissections and mechanical modelling, we describe the mechanism by which the male produces his courtship signal...
March 16, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28299334/evidence-for-startle-effects-due-to-externally-induced-lower-limb-movements-implications-in-neurorehabilitation
#7
Juan M Castellote, Markus Kofler, Andreas Mayr, Leopold Saltuari
Passive limb displacement is routinely used to assess muscle tone. If we attempt to quantify muscle stiffness using mechanical devices, it is important to know whether kinematic stimuli are able to trigger startle reactions. Whether kinematic stimuli are able to elicit a startle reflex and to accelerate prepared voluntary movements (StartReact effect) has not been studied extensively to date. Eleven healthy subjects were suspended in an exoskeleton and were exposed to passive left knee flexion (KF) at three intensities, occasionally replaced by fast right KF...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28297683/effects-of-hypothermia-on-the-mechanical-behavior-of-rabbit-femoral-arteries
#8
Kozaburo Hayashi, Yuki Kurose
The need to better understand the effects of non-physiological temperatures on arterial wall behavior is becoming more important because of the increased clinical use of hypothermal and hyperthermal treatments. The present study was performed to examine the effects of temperature on the mechanical behavior of femoral arteries excised from rabbits. Among 17, 27, 37, and 42°C, there were no significant differences in their diameter, stiffness, and P-D relations under the physiologically normal, control condition, although the arterial diameter was slightly smaller at 42°C than at the other three temperatures...
March 6, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28297657/modeling-the-actin-myosin-atpase-cross-bridge-cycle-for-skeletal-and-cardiac-muscle-myosin%C3%A2-isoforms
#9
Srbolujub M Mijailovich, Djordje Nedic, Marina Svicevic, Boban Stojanovic, Jonathan Walklate, Zoltan Ujfalusi, Michael A Geeves
Modeling the complete actin.myosin ATPase cycle has always been limited by the lack of experimental data concerning key steps of the cycle, because these steps can only be defined at very low ionic strength. Here, using human β-cardiac myosin-S1, we combine published data from transient and steady-state kinetics to model a minimal eight-state ATPase cycle. The model illustrates the occupancy of each intermediate around the cycle and how the occupancy is altered by changes in actin concentration for [actin] = 1-20Km...
March 14, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28296926/relationship-between-decreased-lower-extremity-muscle-mass-and-knee-pain-severity-in-both-the-general-population-and-patients-with-knee-osteoarthritis-findings-from-the-knhanes-v-1-2
#10
Yun-Hong Cheon, Hyun-Ok Kim, Young Sun Suh, Min Gyo Kim, Wan-Hee Yoo, Rock Bum Kim, Hyun-Su Yang, Sang-Il Lee, Ki-Soo Park
OBJECTIVE: To identify the prevalence of and risk factors for knee pain and radiographic knee osteoarthritis (RKOA) and to investigate the relationship between decreased lower extremity muscle mass (DLEM) and knee pain severity. METHODS: Using data from the Korea National Health and Nutrition Examination Survey, 3,278 participants who were ≥50 years old and who underwent dual x-ray absorptiometry, plain knee radiographs and completed a knee pain questionnaire were enrolled...
2017: PloS One
https://www.readbyqxmd.com/read/28293194/quantification-of-internal-stress-strain-fields-in-human-tendon-unraveling-the-mechanisms-that-underlie-regional-tendon-adaptations-and-mal-adaptations-to-mechanical-loading-and-the-effectiveness-of-therapeutic-eccentric-exercise
#11
REVIEW
Constantinos N Maganaris, Panagiotis Chatzistergos, Neil D Reeves, Marco V Narici
By virtue of their anatomical location between muscles and bones, tendons make it possible to transform contractile force to joint rotation and locomotion. However, tendons do not behave as rigid links, but exhibit viscoelastic tensile properties, thereby affecting the length and contractile force in the in-series muscle, but also storing and releasing elastic stain energy as some tendons are stretched and recoiled in a cyclic manner during locomotion. In the late 90s, advancements were made in the application of ultrasound scanning that allowed quantifying the tensile deformability and mechanical properties of human tendons in vivo...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28290056/relationship-between-isometric-contraction-intensity-and-muscle-hardness-assessed-by-ultrasound-strain-elastography
#12
Takayuki Inami, Toru Tsujimura, Takuya Shimizu, Takemasa Watanabe, Wing Yin Lau, Kazunori Nosaka
INTRODUCTION: Ultrasound elastography is used to assess muscle hardness or stiffness; however, no previous studies have validated muscle hardness measures using ultrasound strain elastography (SE). This study investigated the relationship between plantar flexor isometric contraction intensity and gastrocnemius hardness assessed by SE. We hypothesised that the muscle would become harder linearly with an increase in the contraction intensity of the plantar flexors. METHODS: Fifteen young women (20...
March 13, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28287979/ankle-joint-intrinsic-dynamics-is-more-complex-than-a-mass-spring-damper-model
#13
Ehsan Sobhani Tehrani, Kian Jalaleddini, Robert E Kearney
This paper describes a new small signal parametric model of ankle joint intrinsic mechanics in normal subjects. We found that intrinsic ankle mechanics is a 3rd order system and the 2nd order mass-spring-damper model, referred to as IBK, used by many researchers in the literature cannot adequately represent ankle dynamics at all frequencies in a number of important tasks. This was demonstrated using experimental data from five healthy subjects with no voluntary muscle contraction and at seven ankle positions covering the range of motion...
March 8, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28285729/evaluation-of-post-stroke-spastic-muscle-stiffness-using-shear-wave-ultrasound-elastography
#14
Chueh-Hung Wu, Yu-Chun Ho, Ming-Yen Hsiao, Wen-Shiang Chen, Tyng-Guey Wang
Current clinical evaluations of post-stroke upper limb spasticity are subjective and qualitative. We proposed a quantitative measurement of post-stroke spastic muscle stiffness by using shear-wave ultrasound elastography and tested its reliability. Acoustic radiation force impulse with shear wave velocity (SWV) detection was used to evaluate stiffness of the biceps brachii muscles at 90° and 0° elbow flexion. In 21 control subjects, SWV did not significantly differ between dominant and non-dominant sides at either flexion angle (0°: p = 0...
March 9, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28282755/the-acute-effects-of-an-intense-stretch-shortening-cycle-fatigue-protocol-on-the-neuromechanical-parameters-of-lower-limbs-in-men-and-prepubescent-boys
#15
Savvas Lazaridis, Dimitrios A Patikas, Eleni Bassa, Themistoklis Tsatalas, Konstantinos Hatzikotoulas, Christos Ftikas, Christos Kotzamanidis
The study examined the differences between boys and adults after an intense stretch-shortening cycle fatigue protocol on neuromechanical parameters of the lower limb. Thirteen boys (9-11 years old) and 13 adult men (22-28 years old) were tested for maximal isometric voluntary knee extension torque and drop jump (DJ) performance from 30 cm before and immediately after a fatigue protocol, consisted of 10 × 10 maximum effort vertical jumps. Three-dimensional kinematics, kinetics and electromyographic (EMG) parameters of the lower extremities muscles were recorded during DJs before and after the fatigue test...
February 8, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28280975/the-effect-of-nordic-hamstring-strength-training-on-muscle-architecture-stiffness-and-strength
#16
Kayla D Seymore, Zachary J Domire, Paul DeVita, Patrick M Rider, Anthony S Kulas
PURPOSE: Hamstring strain injury is a frequent and serious injury in competitive and recreational sports. While Nordic hamstring (NH) eccentric strength training is an effective hamstring injury-prevention method, the protective mechanism of this exercise is not understood. Strength training increases muscle strength, but also alters muscle architecture and stiffness; all three factors may be associated with reducing muscle injuries. The purpose of this study was to examine the effects of NH eccentric strength training on hamstring muscle architecture, stiffness, and strength...
March 9, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28279204/a-study-to-compare-the-efficacy-of-polyether-ether-ketone-rod-device-with-titanium-devices-in-posterior-spinal-fusion-in-a-canine-model
#17
Nanxiang Wang, Huanxin Xie, Chunyang Xi, Han Zhang, Jinglong Yan
BACKGROUND: The benefits of posterior lumbar fusion surgery with orthotopic paraspinal muscle-pediculated bone flaps are well established. However, the problem of non-union due to mechanical support is not completely resolved. The aim of the study was to compare the efficacy of polyether ether ketone (PEEK) rod device with conventional titanium devices in the posterior lumbar fusion surgery with orthotopic paraspinal muscle-pediculated bone flaps. METHODS: This was a randomized controlled study with an experimental animal model...
March 9, 2017: Journal of Orthopaedic Surgery and Research
https://www.readbyqxmd.com/read/28277127/a-successful-case-of-pregnancy-in-a-woman-with-acth-independent-cushing-s-syndrome-treated-with-ketoconazole-and-metyrapone
#18
Wojciech Zieleniewski, Renata Michalak
Cushing's syndrome (CS) is a rare disease caused by a chronic excess of cortisol. Hypercortisolaemia may affect reproductive system leading to infertility in women. However, some of the patients remain fertile, although pregnancy is uncommon. In our report, we describe the case of a 31-years old woman suffering from hypertension, oligomenorrhea, easy bruising, muscle weakness and elevated levels of cortisol. During hospitalization, high level of serum cortisol with stiff diurnal rhythm and undetectable plasma ACTH concentration were found...
February 26, 2017: Gynecological Endocrinology
https://www.readbyqxmd.com/read/28274273/acute-effects-of-foam-rolling-on-passive-tissue-stiffness-and-fascial-sliding-study-protocol-for-a-randomized-controlled-trial
#19
Frieder Krause, Jan Wilke, Daniel Niederer, Lutz Vogt, Winfried Banzer
BACKGROUND: Self-myofascial release (SMR) aims to mimic the effects of manual therapy and tackle dysfunctions of the skeletal muscle and connective tissue. It has been shown to induce improvements in flexibility, but the underlying mechanisms are still poorly understood. In addition to neuronal mechanisms, improved flexibility may be driven by acute morphological adaptations, such as a reduction in passive tissue stiffness or improved movement between fascial layers. The aim of the intended study is to evaluate the acute effects of SMR on the passive tissue stiffness of the anterior thigh muscles and the sliding properties of the associated fasciae...
March 9, 2017: Trials
https://www.readbyqxmd.com/read/28272927/muscle-degeneration-associated-with-rotator-cuff-tendon-release-and-or-denervation-in-sheep
#20
Christian Gerber, Dominik C Meyer, Martin Flück, Paola Valdivieso, Brigitte von Rechenberg, Mario C Benn, Karl Wieser
BACKGROUND: The effect of an additional neurological injury (suprascapular nerve traction injury) to a chronically retracted rotator cuff muscle is incompletely understood and warrants clarification. PURPOSE: To investigate the microscopic and macroscopic muscle degeneration patterns caused by tendon release and/or muscle denervation in a sheep rotator cuff model. STUDY DESIGN: Controlled laboratory study. METHODS: Infraspinatus muscle biopsy specimens (for histological analysis) were obtained from 18 Swiss alpine sheep before and 16 weeks after release of the infraspinatus tendon (tenotomy [T] group; n = 6), transection of the suprascapular nerve (neurectomy [N] group; n = 6), or tendon release plus nerve transection (tenotomy + neurectomy [T&N] group; n = 6)...
March 2017: American Journal of Sports Medicine
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