Artículos de revistas: "Neuromuscular spindle"

1

Rodger, J., M. R. Ziman, J. M. Papadimitriou y P. H. Kay. "Pax7 is expressed in the capsules surrounding adult mouse neuromuscular spindles". Biochemistry and Cell Biology 77, n.º 2 (20 de junio de 1999): 153–56. http://dx.doi.org/10.1139/o99-020.

Texto completo

Resumen

The multigene Pax family of transcription factors plays an important role in the development of the central nervous system as well as in organ morphogenesis. Expression of one of the members of the family, Pax7, has been described in embryonic muscle and in both embryonic and adult brain. We recently detected Pax7 transcripts in RNA isolated from adult mouse skeletal muscle and brain and here use in situ hybridisation to localise the expression within these tissues. Pax7 expression was observed in neural cells of the brain and in cells of neural crest origin in the inner and outer capsules of neuromuscular spindles. The results suggest that Pax7 may be implicated in the formation and maintenance of neuromuscular contacts within the muscle spindle throughout life.Key words: Pax7 expression, skeletal muscle, neuromuscular spindle, basal lamina, Schwann cells.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Andrechek, Eran R., William R. Hardy, Adele A. Girgis-Gabardo, Robert L. S. Perry, Richard Butler, Frank L. Graham, Ronald C. Kahn, Michael A. Rudnicki y William J. Muller. "ErbB2 Is Required for Muscle Spindle and Myoblast Cell Survival". Molecular and Cellular Biology 22, n.º 13 (1 de julio de 2002): 4714–22. http://dx.doi.org/10.1128/mcb.22.13.4714-4722.2002.

Texto completo

Resumen

ABSTRACT Signaling mediated by ErbB2 is thought to play a critical role in numerous developmental processes. However, due to the embryonic lethality associated with the germ line inactivation of erbB2, its role in adult tissues remains largely obscure. Given the expression of ErbB2 at the neuromuscular junction, we have created a muscle-specific knockout to assess its role there. This resulted in viable mice with a progressive defect in proprioception due to loss of muscle spindles. Interestingly, a partial reduction of ErbB2 levels also reduced the number of muscle spindles. Although histological analysis of the muscle revealed an otherwise normal architecture, induction of muscle injury revealed a defect in muscle regeneration. Consistent with these observations, primary myoblasts lacking ErbB2 exhibit extensive apoptosis upon differentiation into myofibers. Taken together, these results illustrate a dual role for ErbB2 in both muscle spindle maintenance and survival of myoblasts.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Selcen, Duygu, William J. Kupsky y David Benjamins. "Myopathy with muscle spindle excess: A new congenital neuromuscular syndrome?" Muscle & Nerve 24, n.º 1 (enero de 2001): 138–43. http://dx.doi.org/10.1002/1097-4598(200101)24:1<138::aid-mus22>3.0.co;2-3.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Wilkerson, Gary B. y Arthur J. Nitz. "Dynamic Ankle Stability: Mechanical and Neuromuscular Interrelationships". Journal of Sport Rehabilitation 3, n.º 1 (febrero de 1994): 43–57. http://dx.doi.org/10.1123/jsr.3.1.43.

Texto completo

Resumen

Ankle proprioception is widely regarded as an important factor that affects susceptibility to ankle sprain, but the precise mechanisms by which proprioceptive abilities may enhance ankle stability are not well understood. Pertinent literature is reviewed and theoretical interrelationships among factors that may affect dynamic ankle function are discussed. Topics addressed include mechanoreceptor function, muscle spindle function, postural balance, ankle edema, joint capsule distension, synovial hypertrophy, capsuloligamentous laxity, anterolateral rotary instability, ankle giving way, reflexive muscle splinting, articular deafferentation, neurogenic inflammation, muscular de-efferentation, and enhancement of compensatory neuromuscular mechanisms. Recommendations for future research are presented in the form of questions that cannot be adequately answered at present concerning the role of proprioceptively mediated mechanisms in the maintenance of dynamic ankle stability.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Leu, M. "Erbb2 regulates neuromuscular synapse formation and is essential for muscle spindle development". Development 130, n.º 11 (1 de junio de 2003): 2291–301. http://dx.doi.org/10.1242/dev.00447.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Hörner, Sarah Janice, Nathalie Couturier, Roman Bruch, Philipp Koch, Mathias Hafner y Rüdiger Rudolf. "hiPSC-Derived Schwann Cells Influence Myogenic Differentiation in Neuromuscular Cocultures". Cells 10, n.º 12 (24 de noviembre de 2021): 3292. http://dx.doi.org/10.3390/cells10123292.

Texto completo

Resumen

Motoneurons, skeletal muscle fibers, and Schwann cells form synapses, termed neuromuscular junctions (NMJs). These control voluntary body movement and are affected in numerous neuromuscular diseases. Therefore, a variety of NMJ in vitro models have been explored to enable mechanistic and pharmacological studies. So far, selective integration of Schwann cells in these models has been hampered, due to technical limitations. Here we present robust protocols for derivation of Schwann cells from human induced pluripotent stem cells (hiPSC) and their coculture with hiPSC-derived motoneurons and C2C12 muscle cells. Upon differentiation with tuned BMP signaling, Schwann cells expressed marker proteins, S100b, Gap43, vimentin, and myelin protein zero. Furthermore, they displayed typical spindle-shaped morphologies with long processes, which often aligned with motoneuron axons. Inclusion of Schwann cells in coculture experiments with hiPSC-derived motoneurons and C2C12 myoblasts enhanced myotube growth and affected size and number of acetylcholine receptor plaques on myotubes. Altogether, these data argue for the availability of a consistent differentiation protocol for Schwann cells and their amenability for functional integration into neuromuscular in vitro models, fostering future studies of neuromuscular mechanisms and disease.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

KARAVASILIS, G. J. y A. G. RIGAS. "THE USE OF NONPARAMETRIC METHODS OF STATIONARY POINT PROCESSES IN THE STUDY OF COMPLEX INTERACTIONS IN THE NEUROMUSCULAR SYSTEM". Journal of Biological Systems 17, n.º 04 (diciembre de 2009): 577–95. http://dx.doi.org/10.1142/s0218339009003095.

Texto completo

Resumen

In this paper we study the complex interactions involved in the incoming stimulus, from a gamma (γ) and/or an alpha (α) motoneuron, and the outgoing response from the muscle spindle transmitted by the Ia sensory afferent neuron to the spinal cord. The most interesting case is the γ and α coactivation to the function of the muscle spindle, while the effect from a single (γ or α) motoneuron is also presented as a comparison. The mathematical background of this analysis is based on the theory of stationary point processes. A kernel type method of estimating second- and third-order conditional densities is used. Under certain conditions the asymptotic distributions of these estimates are Normal and the construction of 95% approximate confidence intervals is feasible. The application of these asymptotic results to the system of the muscle spindle enables us to detect and interpret its excitatory and/or inhibitory behavior.

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Barrett, Philip, Tom J. Quick, Vivek Mudera y Darren J. Player. "Generating intrafusal skeletal muscle fibres in vitro: Current state of the art and future challenges". Journal of Tissue Engineering 11 (enero de 2020): 204173142098520. http://dx.doi.org/10.1177/2041731420985205.

Texto completo

Resumen

Intrafusal fibres are a specialised cell population in skeletal muscle, found within the muscle spindle. These fibres have a mechano-sensory capacity, forming part of the monosynaptic stretch-reflex arc, a key component responsible for proprioceptive function. Impairment of proprioception and associated dysfunction of the muscle spindle is linked with many neuromuscular diseases. Research to-date has largely been undertaken in vivo or using ex vivo preparations. These studies have provided a foundation for our understanding of muscle spindle physiology, however, the cellular and molecular mechanisms which underpin physiological changes are yet to be fully elucidated. Therefrom, the use of in vitro models has been proposed, whereby intrafusal fibres can be generated de novo. Although there has been progress, it is predominantly a developing and evolving area of research. This narrative review presents the current state of art in this area and proposes the direction of future work, with the aim of providing novel pre-clinical and clinical applications.

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Himmel, Lauren y Rachel Cianciolo. "Nodular typhlocolitis, heterakiasis, and mesenchymal neoplasia in a ring-necked pheasant (Phasianus colchicus) with immunohistochemical characterization of visceral metastases". Journal of Veterinary Diagnostic Investigation 29, n.º 4 (3 de mayo de 2017): 561–65. http://dx.doi.org/10.1177/1040638717707555.

Texto completo

Resumen

A 9-y-old, male ring-necked pheasant ( Phasianus colchicus) was autopsied following euthanasia because of acute distress, recumbency, and dyspnea. The bird had experienced a protracted period of neuromuscular disease localized to the left sciatic nerve. Gross and histologic examination of the large intestine revealed intramural nodules predominantly comprised of atypical, whorling spindle cells with small cores of granulomatous inflammation centered on cross-sections of immature adult nematodes. The body structures of these metazoan organisms and clinical disease manifestation are consistent with Heterakis isolonche infection. Nodular spindle cell proliferations without granulomatous inflammation or intralesional nematodes were also found throughout the liver and lungs, suggesting metastasis from the intestine. Immunohistochemical staining of the hepatic and pulmonary tumor tissue with vimentin and S100 suggests a neurofibroblastic origin.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Werle, Michael J., John Roder y Andreas Jeromin. "Expression of frequenin at the frog (Rana) neuromuscular junction, muscle spindle and nerve". Neuroscience Letters 284, n.º 1-2 (abril de 2000): 33–36. http://dx.doi.org/10.1016/s0304-3940(00)01004-1.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Carr, R. W., D. L. Morgan y U. Proske. "Impulse initiation in the mammalian muscle spindle during combined fusimotor stimulation and succinyl choline infusion". Journal of Neurophysiology 75, n.º 4 (1 de abril de 1996): 1703–13. http://dx.doi.org/10.1152/jn.1996.75.4.1703.

Texto completo

Resumen

1. This is a report of observations on the responses of the primary and secondary endings of soleus muscle spindles of the anesthetized cat to the combined effects of the depolarizing neuromuscular blocker succinyl choline (SCh), given intravenously, and fusimotor stimulation. The findings were interpreted in terms of a dual pacemaker model for activity generated in the bag1 intrafusal fiber interacting with activity coming from bag2 and chain fibers. 2. In preliminary experiments it was found, using whole ventral root stimulation at fusimotor strength, that spindle responses to fusimotor stimulation were not blocked by SCh, whereas extrafusal junctions blocked rapidly. In the presence of SCh, fusimotor responses of spindle secondary endings were, on average, slightly larger than their control values before SCh was given, whereas fusimotor responses of primary endings were slightly smaller. 3. A study of the responses of spindle primary endings to stimulation of single dynamic (gamma D) and static (gamma S) axons in the presence of SCh revealed a fundamental difference in behavior. None of the responses to stimulation of gamma D axons (9 gamma D axons with 8 primary endings) showed significant summation with the responses to SCh. By contrast, the 20 gamma S axons studied showed varying degrees of summation with the responses to SCh. The responses of secondary endings to gamma S stimulation in the presence of SCh resembled those of primary endings and gamma S stimulation. 4. To explain these differences it is proposed that the primary ending has two separate sites of impulse initiation, one close to terminals on the bag1 intrafusal fiber (innervated by gamma D axons) and a second close to terminals on the bag2 and chain fibers (innervated by gamma S axons). It is proposed that the maintained increase in spindle firing observed during SCh infusion is the result of a bag2 contracture. The response to gamma S stimulation, contracting bag2 and chain fibers, adds to the SCh response. The degree of summation varies depending on whether the gamma S activates bag2 fibers, chain fibers, or both. The bag1 contracture, together with the effects of gamma D stimulation, acts through a separate pacemaker and therefore does not sum with the steady increase in spindle firing in the presence of SCh. There may be pacemaker switching between the bag1 generator and the bag2 and chain generator. 5. If the model is representative of most spindles containing the three kinds of intrafusal fibers, and the contractions of bag2 and chain fibers generate activity through a common impulse generator, then this bears on the question of the functional independence of the bag2 and chain fiber systems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Russo, Maria y Giuseppe Cultrera. "The physiotherapeutic “Variable Approach Technique”: an example of neuromotor adaptation conveyed by the neuromuscular spindle". Clinical Case Reports 6, n.º 2 (22 de diciembre de 2017): 288–301. http://dx.doi.org/10.1002/ccr3.1339.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Carter, Allyson M., Stephen J. Kinzey, Linda F. Chitwood y Judith L. Cole. "Proprioceptive Neuromuscular Facilitation Decreases Muscle Activity during the Stretch Reflex in Selected Posterior Thigh Muscles". Journal of Sport Rehabilitation 9, n.º 4 (noviembre de 2000): 269–78. http://dx.doi.org/10.1123/jsr.9.4.269.

Texto completo

Resumen

Context:Proprioceptive neuromuscular facilitation (PNF) is commonly used before competition to increase range of motion. It is not known how it changes muscle response to rapid length changes.Objective:To determine whether PNF alters hamstring muscle activity during response to rapid elongation.Design:2 X 2 factorial.Setting:Laboratory.Participants:Twenty-four women; means: 167.27 cm, 58.92 kg, 21.42 y, 18.41% body fat, 21.06 kg/m2BMI.intervention:Measurements before and after either rest or PNF were compared.Main Outcome Measures:Average muscle activity immediately after a rapid and unexpected stretch, 3 times pretreatment and posttreatment, averaged into 2 pre-and post- measures.Results:PNF caused decreased activity in the biceps femoris during response to a sudden stretch (P= .04). No differences were found in semitendinosus activity (P= .35).Conclusions:Decreased muscle activity likely results from acute desensitization of the muscle spindle, which might increase risk of muscle and tendon injury.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Layne, Charles S., Katharine E. Forth y Andrew F. J. Abercromby. "Spatial factors and muscle spindle input influence the generation of neuromuscular responses to stimulation of the human foot". Acta Astronautica 56, n.º 9-12 (mayo de 2005): 809–19. http://dx.doi.org/10.1016/j.actaastro.2005.01.006.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Roberts, Thomas J. "Some Challenges of Playing with Power: Does Complex Energy Flow Constrain Neuromuscular Performance?" Integrative and Comparative Biology 59, n.º 6 (26 de junio de 2019): 1619–28. http://dx.doi.org/10.1093/icb/icz108.

Texto completo

Resumen

Abstract Many studies of the flow of energy between the body, muscles, and elastic elements highlight advantages of the storage and recovery of elastic energy. The spring-like action of structures associated with muscles allows for movements that are less costly, more powerful and safer than would be possible with contractile elements alone. But these actions also present challenges that might not be present if the pattern of energy flow were simpler, for example, if power were always applied directly from muscle to motions of the body. Muscle is under the direct control of the nervous system, and precise modulation of activity can allow for finely controlled displacement and force. Elastic structures deform under load in a predictable way, but are not under direct control, thus both displacement and the flow of energy act at the mercy of the mechanical interaction of muscle and forces associated with movement. Studies on isolated muscle-tendon units highlight the challenges of controlling such systems. A carefully tuned activation pattern is necessary for effective cycling of energy between tendon and the environment; most activation patterns lead to futile cycling of energy between tendon and muscle. In power-amplified systems, “elastic backfire” sometimes occurs, where energy loaded into tendon acts to lengthen active muscles, rather than accelerate the body. Classic models of proprioception that rely on muscle spindle organs for sensing muscle and joint displacement illustrate how elastic structures might influence sensory feedback by decoupling joint movement from muscle fiber displacements. The significance of the complex flow of energy between muscles, elastic elements and the body for neuromotor control is worth exploring.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Metzger, Roman, Udo Rolle, Henning C. Fiegel, Folker E. Franke, Karsten Muenstedt y Holger Till. "C-kit receptor in the human vas deferens: distinction of mast cells, interstitial cells and interepithelial cells". REPRODUCTION 135, n.º 3 (marzo de 2008): 377–84. http://dx.doi.org/10.1530/rep-07-0346.

Texto completo

Resumen

The molecular mechanisms underlying the regulation of vas deferens (VD) motility and semen emission are still poorly understood. Interstitial cells of Cajal (ICC), which harbour the c-kit receptor (CD117), provide the basis of coordinated gut motility. We investigated whether c-kit receptor-positive cells also exist in the normal human VD. Enzyme and fluorescence immunohistochemical techniques were applied on serial sections of human proximal, middle, and distal VD segments (n=49) employing 13 different monoclonal and polyclonal antibodies recognizing the c-kit receptor. The c-kit receptor was detected in either round- or spindle-shaped cells. On account of their antigenic profile, the round- and oval-shaped c-kit receptor-positive cells were identified as mast cells (MC) occurring in all layers of the VD except the epithelium. In contrast, two distinct populations of exclusively c-kit receptor-positive spindle-shaped cells were found within the lamina propria and, rarely, in the inner and outer smooth muscle layers, as well as within the epithelium. Different shaped c-kit receptor-positive MC and IC were present in all layers of the human VD. Our findings demonstrate the presence of different c-kit receptor-positive cells also in the human VD. Their rather ubiquitous distribution within the lamina propria and muscle layers suggests that IC and MC may modulate the neuromuscular transmission and the propagation of electrical signals in multiple systems involved in the draining of fluids. The importance of the c-kit receptor-positive interepithelial cells remains unclear.

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Sanes, J. R., Y. R. Johnson, P. T. Kotzbauer, J. Mudd, T. Hanley, J. C. Martinou y J. P. Merlie. "Selective expression of an acetylcholine receptor-lacZ transgene in synaptic nuclei of adult muscle fibers". Development 113, n.º 4 (1 de diciembre de 1991): 1181–91. http://dx.doi.org/10.1242/dev.113.4.1181.

Texto completo

Resumen

Acetylcholine receptors (AChRs) are highly concentrated in the postsynaptic membrane at the neuromuscular junction. To investigate mechanisms that lead to the formation or maintenance of this synaptic specialization, we generated transgenic mice in which regulatory elements from the AChR alpha or epsilon-subunit genes are linked to a gene for a reporter protein that is targeted to the nucleus (nlacZ). Both transgenes were selectively expressed and developmentally regulated in muscle; nuclei in both extrafusal (ordinary) and intrafusal (spindle) muscle fibers were labeled. Within individual muscle fibers from epsilon-nlacZ mice, nuclei near synaptic sites were nlacZ-positive, whereas extrasynaptic nuclei were nlacZ-negative. In contrast, nlacZ was expressed in both synaptic and extrasynaptic nuclei when under the control of regulatory elements from the AChR alpha-subunit gene; however, synaptic nuclei were somewhat more intensely stained than extrasynaptic nuclei in a minority of muscle fibers from these mice. Together, our results provide direct evidence for molecular differences between synaptic and extrasynaptic nuclei within a single cytoplasm, and suggest that the motor nerve regulates synapse formation by selectively affecting transcription in synaptic nuclei.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Ito, Naoki, Yuko Miyagoe-Suzuki, Shin’ichi Takeda y Akira Kudo. "Periostin Is Required for the Maintenance of Muscle Fibers during Muscle Regeneration". International Journal of Molecular Sciences 22, n.º 7 (31 de marzo de 2021): 3627. http://dx.doi.org/10.3390/ijms22073627.

Texto completo

Resumen

Skeletal muscle regeneration is a well-organized process that requires remodeling of the extracellular matrix (ECM). In this study, we revealed the protective role of periostin, a matricellular protein that binds to several ECM proteins during muscle regeneration. In intact muscle, periostin was localized at the neuromuscular junction, muscle spindle, and myotendinous junction, which are connection sites between muscle fibers and nerves or tendons. During muscle regeneration, periostin exhibited robustly increased expression and localization at the interstitial space. Periostin-null mice showed decreased muscle weight due to the loss of muscle fibers during repeated muscle regeneration. Cultured muscle progenitor cells from periostin-null mice showed no deficiencies in their proliferation, differentiation, and the expression of Pax7, MyoD, and myogenin, suggesting that the loss of muscle fibers in periostin-null mice was not due to the impaired function of muscle stem/progenitor cells. Periostin-null mice displayed a decreased number of CD31-positive blood vessels during muscle regeneration, suggesting that the decreased nutritional supply from blood vessels was the cause of muscle fiber loss in periostin-null mice. These results highlight the novel role of periostin in maintaining muscle mass during muscle regeneration.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Lin, David C. y W. Zev Rymer. "Damping Actions of the Neuromuscular System With Inertial Loads: Human Flexor Pollicis Longus Muscle". Journal of Neurophysiology 85, n.º 3 (1 de marzo de 2001): 1059–66. http://dx.doi.org/10.1152/jn.2001.85.3.1059.

Texto completo

Resumen

Our previous work in an animal model showed that neuromuscular damping properties help maintain limb posture by effectively dissipating mechanical energy arising from disturbances. The purpose of this study was to determine whether similar damping properties were expressed in intact, normal human muscles. To review briefly, when the reflexively active soleus muscle in a decerebrate cat is coupled to an inertial load, application of a force impulse to the load results in lightly damped oscillations. By calculating the logarithmic decrement in muscle velocity following the impulse (the decrement being related to the amount of energy dissipated from the inertia), we found that damping increased with oscillation amplitude, a nonlinear property. This nonlinearity represents an automatic compensation for larger perturbations. Our findings in parallel experiments on the interphalangeal joint of the human thumb were that the long thumb flexor, the flexor pollicis longus (FPL), displayed mechanical and reflex behavior closely comparable to that reported earlier for the cat soleus, despite differences in architectural and metabolic properties between these muscles. Specifically, by selecting experimental trials that did not include voluntary interventions, we observed amplitude-dependent differences in damping in which larger amplitude movements elicited larger damping than did smaller movements. In addition, even after accounting for amplitude-dependent differences in damping, damping was found to be larger in later cycles than in the first cycle. This nonlinearity indicates that both mechanical properties of muscle and reflex mechanisms are dependent on prior movement history. We propose that this history-dependent behavior arises from the effects of prior movement on stretch reflex gain, and these effects are mediated primarily via changes in muscle spindle properties. Recordings of electromyographic activity from the FPL, during the first and second cycles of oscillation supported this postulate of a reduced reflex gain following prior motion. The functional significance of these nonlinear damping properties is that during the initial muscle stretch, the stiffness is high, which helps to preserve the initial position (although at the expense of promoting oscillation). Subsequently, the ensuing increase in damping helps suppress continuing oscillation. This sequence of varying mechanical properties is broadly analogous to the features of a predictive, or feed-forward controller, designed to produce a response that initially maintains position, and subsequently dampens oscillations. These results show that the intrinsic properties of muscle and spinal reflexes automatically provide a complex time-varying response, appropriate for maintenance of stable limb posture.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Blackburn, J. Troy, Darin A. Padua y Kevin M. Guskiewicz. "Muscle Stiffness and Spinal Stretch Reflex Sensitivity in the Triceps Surae". Journal of Athletic Training 43, n.º 1 (1 de enero de 2008): 29–36. http://dx.doi.org/10.4085/1062-6050-43.1.29.

Texto completo

Resumen

Abstract Context: Greater musculotendinous stiffness may enhance spinal stretch reflex sensitivity by improving mechanical coupling of the muscle spindle and the stretch stimulus. This heightened sensitivity would correspond with a shorter latency and higher-amplitude reflex response, potentially enhancing joint stability. Objective: To compare spinal stretch reflex latency and amplitude across groups that differed in musculotendinous stiffness. Design: Static group comparisons. Setting: Research laboratory. Patients or Other Participants: Forty physically active individuals (20 men, 20 women). Intervention(s): We verified a sex difference in musculotendinous stiffness and compared spinal stretch reflex latency and amplitude in high-stiffness (men) and low-stiffness (women) groups. We also evaluated relationships between musculotendinous stiffness and spinal stretch reflex latency and amplitude, respectively. Main Outcome Measure(s): Triceps surae musculotendinous stiffness and soleus spinal stretch reflex latency and amplitude were assessed at 30% of a maximal voluntary isometric plantar-flexion contraction. Results: The high-stiffness group demonstrated significantly greater stiffness (137.41 ± 26.99 N/cm) than the low-stiffness group did (91.06 ± 20.10 N/cm). However, reflex latency (high stiffness = 50.11 ± 2.07 milliseconds, low stiffness = 48.26 ± 2.40 milliseconds) and amplitude (high stiffness = 0.28% ± 0.12% maximum motor response, low stiffness = 0.31% ± 0.16% maximum motor response) did not differ significantly across stiffness groups. Neither reflex latency (r = .053, P = .746) nor amplitude (r = .073, P = .653) was related significantly to musculotendinous stiffness. Conclusions: A moderate level of pretension (eg, 30%) likely eliminates series elastic slack; thus, a greater change in force per unit-of-length change (ie, heightened stiffness) would have minimal effects on coupling of the muscle spindle and the stretch stimulus and, therefore, on spinal stretch reflex sensitivity. It appears unlikely that differences in musculotendinous stiffness influenced spinal stretch reflex sensitivity when initiated from a moderate level of pretension. Consequently, differences in musculotendinous stiffness did not appear to influence dynamic joint stability with respect to reflexive neuromuscular control.

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Martin, R. J., A. J. Pennington, A. H. Duittoz, S. Robertson y J. R. Kusel. "The physiology and pharmacology of neuromuscular transmission in the nematode parasite,Ascaris suum". Parasitology 102, S1 (enero de 1991): S41—S58. http://dx.doi.org/10.1017/s0031182000073285.

Texto completo

Resumen

The organization ofAscarismotoneurones and nervous system is summarized. There is an anterior nerve ring and associated ganglia, main dorsal and ventral nerve cords which run longitudinally, and a small set of posterior ganglia. Cell bodies of motoneurones are found in the ventral nerve cord and occur in 5 repeating ‘segments’; each contains 11 motoneurones. Seven morphological types of excitatory or inhibitory motoneurone are recognized.EachAscarissomatic muscle cell is composed of the contractile spindle; the bag region, containing the nucleus; the arm; and the syncytial region, the location of neuromuscular junctions. The resting membrane potential of muscle is approximately — 30 mV and shows regular depolarizing, Ca-dependent ‘spike potentials’ superimposed on smaller Na+- and Ca2+-dependent ‘slow waves’ and even slower ‘modulation waves’. The membrane shows high Cl-permeability. Adjacent cells are electrically coupled so that electrical activity in the cells is synchronized. Acetylcholine (ACh) and γ-aminobutyric acid (GABA) affect the electrical activity. Bath-applied ACh increases membrane cation conductance, depolarizes the cells, alters the frequency and amplitude of spike potentials and produces contraction. Bath-applied GABA increases Cl-conductance, decreases spike activity and causes hyperpolarization and muscle relaxation.The extra-synaptic ACh receptors on the bag region ofAscarismuscle can be regarded as a separate subtype of nicotinic receptor. ACh and anthelmintic agonists (pyrantel, morantel, levamisole) produce a dose-dependent increase in cation conductance and membrane depolarization which is blocked by tubocurarine, mecamylamine but not by hexamethonium. The potency, of GABA agonists, with the exception of sulphonic acid derivatives, correlates with the vertebrate GABAareceptor. The potency of antagonists does not. Thus, bicuculline, securinine, pitrazepine, SR95531 and RU5135 are potent vertebrate GABAaantagonists but have little effect on GABA receptors. The potency order of the arylaminopyridazine GABA antagonists: SR95103, SR95132, SR42666, SR95133, SR95531, SR42627 and SR42640 at theAscarisGABA receptors contrasts with that at vertebrate GABAareceptors. It has been suggested that the receptor is referred to as a GABAnreceptor.Patch-clamp studies show that ACh activates a non-selective cation channel which has a main conductance of 40–50pS and apparent mean open time of 1·3 ms; a smaller channel of 20–30 pS with a similar open-time is also activated. Pyrantel and levamisole also produce openings with similar conductances and open-times. GABA activates a Cl-channel with a main state conductance of 22 pS and an apparent mean open duration of 32 ms; conductance states of 10 and 15 pS are also seen. Piperazine similarly activates this channel but the mean open-time is shorter (14 ms). Ivermectin in high doses, is an antagonist which reduces the GABA channel conductance and Popen; it does, however, open ‘small’ Cl-channels when applied to the outside surface of membrane. These channels have a conductance of 9–15 pS and very long open times (> 100 mS). 5-HT does not have a direct effect on membrane potential or conductance but acts on cAMP levels and glycogen metabolism. Dopamine, octopamine and AF1 may act as neurotransmitters or neuromodulators.

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Mynark, Richard G. y David M. Koceja. "Effects of Age on the Spinal Stretch Reflex". Journal of Applied Biomechanics 17, n.º 3 (agosto de 2001): 188–203. http://dx.doi.org/10.1123/jab.17.3.188.

Texto completo

Resumen

The spinal stretch reflex consists of a relatively simple neuronal network. The Ia afferent fiber of the muscle spindle communicates to the alpha motoneuron via a single synapse. This basic pathway has been studied extensively over the past century, yet considerable information continues to emerge concerning the manner in which this pathway adapts to aging. It is well accepted that the amplitude of the spinal stretch reflex declines with normal aging, and it is intuitively agreed that these changes have a detrimental impact on the motor output of aging individuals. Understanding the changes observed in the spinal stretch reflex pathway due to aging requires a recognition of the changes that can occur in each component of this spinal network. This review will address these changes by following the spinal stretch reflex from initiation to completion. The components that result in the sensory input to the motoneuron will be covered first, followed by a review of the physiological changes that can occur to the motoneuron soma that can affect the processing of the sensory input. The output of the motoneuron encompasses the remaining components from the motor axon itself, to the neuromuscular junction, and then to the characteristic changes in the muscle. Finally, the functional effect that these changes have on the reflex as a fundamental motor behavior will be addressed, especially in terms of its impact on posture and balance.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Basham, Stephen E. y Lesilee S. Rose. "The Caenorhabditis elegans polarity gene ooc-5 encodes a Torsin-related protein of the AAA ATPase superfamily". Development 128, n.º 22 (15 de noviembre de 2001): 4645–56. http://dx.doi.org/10.1242/dev.128.22.4645.

Texto completo

Resumen

The PAR proteins are required for polarity and asymmetric localization of cell fate determinants in C. elegans embryos. In addition, several of the PAR proteins are conserved and localized asymmetrically in polarized cells in Drosophila, Xenopus and mammals. We have previously shown that ooc-5 and ooc-3 mutations result in defects in spindle orientation and polarity in early C. elegans embryos. In particular, mutations in these genes affect the re-establishment of PAR protein asymmetry in the P1 cell of two-cell embryos. We now report that ooc-5 encodes a putative ATPase of the Clp/Hsp100 and AAA superfamilies of proteins, with highest sequence similarity to Torsin proteins; the gene for human Torsin A is mutated in individuals with early-onset torsion dystonia, a neuromuscular disease. Although Clp/Hsp100 and AAA family proteins have roles in diverse cellular activities, many are involved in the assembly or disassembly of proteins or protein complexes; thus, OOC-5 may function as a chaperone. OOC-5 protein co-localizes with a marker of the endoplasmic reticulum in all blastomeres of the early C. elegans embryo, in a pattern indistinguishable from that of OOC-3 protein. Furthermore, OOC-5 localization depends on the normal function of the ooc-3 gene. These results suggest that OOC-3 and OOC-5 function in the secretion of proteins required for the localization of PAR proteins in the P1 cell, and may have implications for the study of torsion dystonia.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Díaz‐Flores, Lucio, Ricardo Gutiérrez, Francisco J. Sáez, Lucio Díaz‐Flores y Juan F. Madrid. "Telocytes in neuromuscular spindles". Journal of Cellular and Molecular Medicine 17, n.º 4 (abril de 2013): 457–65. http://dx.doi.org/10.1111/jcmm.12015.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Schulze, Stacey L., Susan K. Danielson, John S. Rhee, Robert J. Toohill, Judith I. Kulpa y Safwan S. Jaradeh. "Morphology of the Cricopharyngeal Muscle in Zenker and Control Specimens". Annals of Otology, Rhinology & Laryngology 111, n.º 7 (julio de 2002): 573–78. http://dx.doi.org/10.1177/000348940211100702.

Texto completo

Resumen

The cricopharyngeal muscle (CPM) is essential for normal deglutition. Pharyngeal dysphagia commonly results from impaired or uncoordinated CPM dilation. Dysfunction of the CPM has also been implicated in the genesis of Zenker's (pharyngoesophageal) diverticulum. Despite the CPM's significance, little is understood about its morphology. We studied CPM biopsy specimens from 20 patients with Zenker's diverticulum and from 5 fresh cadaver patients with detailed histologic techniques to include fiber size and shape and adenosine triphosphatase, reduced nicotinamide adenine dinucleotide, trichrome, succinate dehydrogenase, cytochrome C oxidase, periodic acid-Schiff reaction, oil red O, acid phosphatase, Congo red, crystal violet, and monoadenylate deaminase stains. The normal CPM has unique morphological characteristics, with some myofibers having staining properties that are a hybrid between striated muscle and muscle spindle. The variable orientation of the muscle fibers is also different from that of most other striated musculature. Of the 20 Zenker CPM specimens, 4 specimens did not reveal any significant differences from controls (2 of which had insufficient amounts of tissue for complete analysis). In the remaining 16 specimens, several abnormalities existed, including excessive size variation (16/16), grouping of atrophic fibers (9/16), target or targetoid formations (4/16), cores (2/16), and ragged red fibers (2/16). The final pathological pattern of the 16 specimens was neurogenic in 7, myopathic in 4, and mixed (with neurogenic predominance) in the remaining 5. Two specimens contained significant lymphocytic inflammatory infiltrates. We conclude that the unique neuromuscular function of the CPM in deglutition is likely due to its fiber orientation and the hybrid nature of some of the myofibers. Morphological disturbances of the CPM impair its dilation and may account for the development of Zenker's diverticulum. This disturbance is most often due to progressive denervation of the CPM.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Cobine, C. A., G. W. Hennig, Y. R. Bayguinov, W. J. Hatton, S. M. Ward y K. D. Keef. "Interstitial cells of Cajal in the cynomolgus monkey rectoanal region and their relationship to sympathetic and nitrergic nerves". American Journal of Physiology-Gastrointestinal and Liver Physiology 298, n.º 5 (mayo de 2010): G643—G656. http://dx.doi.org/10.1152/ajpgi.00260.2009.

Texto completo

Resumen

The morphology of interstitial cells of Cajal (ICC) in the circular muscle layer of the cynomolgus monkey internal anal sphincter (IAS) and rectum and their relationship to sympathetic and nitrergic nerves were compared by dual-labeling immunohistochemistry. Contractile studies confirmed that nitrergic nerves participate in neural inhibition in both regions whereas sympathetic nerves serve as excitatory motor nerves only in the IAS. Muscle bundles extended from myenteric to submucosal edge in rectum but in the IAS bundles were further divided into “minibundles” each surrounded by connective tissue. Dual labeling of KIT and smooth muscle myosin revealed KIT-positive stellate-shaped ICC (ICC-IAS) within each minibundle. In the rectum intramuscular ICC (ICC-IM) were spindle shaped whereas stellate-shaped ICC were located at the myenteric surface (ICC-MY). ICC were absent from both the myenteric and submucosal surfaces of the IAS. Nitrergic nerves (identified with anti-neuronal nitric oxide synthase antibodies or NADPH diaphorase activity) and sympathetic nerves (identified with anti-tyrosine hydroxylase antibody) each formed a plexus at the myenteric surface of the rectum but not the IAS. Intramuscular neuronal nitric oxide synthase- and tyrosine hydroxylase-positive fibers were present in both regions but were only closely associated with ICC-IM in rectum. Minimal association was also noted between ICC-IAS and cells expressing the nonspecific neuronal marker PGP9.5. In conclusion, the morphology of rectal ICC-IM and ICC-MY is similar to that described elsewhere in the gastrointestinal tract whereas ICC-IAS are unique. The distribution of stellate-shaped ICC-IAS throughout the musculature and their absence from both the myenteric and submucosal surfaces suggest that ICC-IAS may serve as pacemaker cells in this muscle whereas their limited relationship to nerves suggests that they are not involved in neuromuscular transmission. Additionally, the presence of numerous minibundles, each containing both ICC-IAS and nerves, suggests that this muscle functions as a multiunit type muscle.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Buxton, Donald F. y David Peck. "Neuromuscular spindles relative to joint movement complexities". Clinical Anatomy 2, n.º 4 (1989): 211–24. http://dx.doi.org/10.1002/ca.980020402.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Mytskan, B. M. y E. P. Mel'man. "Morphometric characteristics of neuromuscular spindles of hypertrophied skeletal muscle". Bulletin of Experimental Biology and Medicine 102, n.º 5 (noviembre de 1986): 1604–6. http://dx.doi.org/10.1007/bf00854706.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Pedrosa-Domellöf, Fatima, Ismo Virtanen y Lars-Eric Thornell. "Tenascin is present in human muscle spindles and neuromuscular junctions". Neuroscience Letters 198, n.º 3 (octubre de 1995): 173–76. http://dx.doi.org/10.1016/0304-3940(95)11986-7.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Prochazka, Arthur, Deborah Gillard y David J. Bennett. "Positive Force Feedback Control of Muscles". Journal of Neurophysiology 77, n.º 6 (1 de junio de 1997): 3226–36. http://dx.doi.org/10.1152/jn.1997.77.6.3226.

Texto completo

Resumen

Prochazka, Arthur, Deborah Gillard, and David J. Bennett. Positive force feedback control of muscles. J. Neurophysiol. 77: 3226–3236, 1997. This study was prompted by recent evidence for the existence of positive force feedback in feline locomotor control. Our aim was to establish some basic properties of positive force feedback in relation to load compensation, stability, intrinsic muscle properties, and interaction with displacement feedback. In human subjects, muscles acting about the wrist and ankle were activated by feedback-controlled electrical stimulation. The feedback signals were obtained from sensors monitoring force and displacement. The signals were filtered to mimic transduction by mammalian tendon organ and muscle spindle receptors. We found that when muscles under positive force feedback were loaded inertially, they responded in a stable manner with increased active force. The activation attenuated the muscle stretch (yield) that would otherwise occur in the absence of feedback. With enough positive force feedback gain, yield could actually reverse. This behavior, which we termed the affirming reaction, was reminiscent of the mammalian positive supporting reaction, a postural response elicited by contact of the foot with the ground. Muscles under positive force feedback remained stable, even when the loop gain ( G f) was set at levels of 2 or 3. In a linear system, if G f > 1, instability occurs when the loop is closed. On further investigation, we found that G f changed with joint angle: it declined as the load-bearing muscle actively shortened. We inferred that in closed-loop operation, the active muscles always shortened until G f approached unity. In other words, the length-tension curve of active muscle ensures stability even when force-related excitation of motoneurons is very large. Concomitant negative displacement feedback reinforced and stabilized load compensation up to a certain gain, beyond which instability occurred. In further trials we included delays of up to 40 ms in the positive force feedback pathway, to model the delays recently described for tendon organ reflexes in cat locomotion. Contrary to expectations, this did not destabilize the loop. Indeed, when instability was deliberately evoked by setting displacement feedback gain high, delays in the positive force feedback pathway actually stabilized control. The stabilization of positive force feedback by inherent properties of the neuromuscular system increases the functional scope to be expected of feedback from force receptors in biological motor control. Our results provide a rationale for the delayed excitatory action of Ib heteronymous input on extensor motoneurons in cat locomotion.

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Barkats, Martine. "Amyotrophie spinale infantile". médecine/sciences 36, n.º 2 (febrero de 2020): 137–40. http://dx.doi.org/10.1051/medsci/2020010.

Texto completo

Resumen

L’amyotrophie spinale ou SMA est la maladie génétique la plus fréquente menant à la mortalité infantile. Cette maladie neuromusculaire est due à l’altération du gène SMN1. Cette anomalie génétique provoque la réduction des taux de protéine Smn, induisant la dégénérescence des neurones moteurs, la faiblesse et l’atrophie musculaire. La thérapie génique, consistant à réintroduire le gène SMN1 normal dans les motoneurones constitue une thérapie de choix pour la SMA. Nous avons montré l’efficacité sans précédent de cette approche chez la souris modèle de SMA après une simple injection intraveineuse d’un AAV9 exprimant SMN1. Une jeune société de biotechnologie, dirigée par le Dr Kaspar, a testé cette approche expérimentale chez de jeunes patients atteints de SMA type 1. Le Dr Mendell, en charge de ce projet clinique, a montré une augmentation significative de la survie et des fonctions motrices des patients (jusqu’à 4 ans) après une seule injection de l’AAV9-SMN (appelé ZolgenSMA) dans la veine du bras ou de la jambe. Cette thérapie, qui a obtenu l’AMM par la FDA le 24 mai 2019, est actuellement la première thérapie génique efficace dans les maladies neuromusculaires.

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Triantafyllou, Asterios. "Immunohistochemical characterization of capsular cells in neuromuscular spindles of the neck". Journal of Oral Pathology & Medicine 36, n.º 8 (20 de abril de 2007): 501–4. http://dx.doi.org/10.1111/j.1600-0714.2007.00534.x.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Quélin, Chloé, Philippe Loget, Céline Rozel, Dominique D'Hervé, Mélanie Fradin, Florence Demurger, Sylvie Odent, Laurent Pasquier, Hélène Cavé y Pascale Marcorelles. "Fetal costello syndrome with neuromuscular spindles excess and p.Gly12Val HRAS mutation". European Journal of Medical Genetics 60, n.º 7 (julio de 2017): 395–98. http://dx.doi.org/10.1016/j.ejmg.2017.03.014.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Yamamoto, T., DL Morgan, JE Gregory y U. Proske. "Blockade of intrafusal neuromuscular junctions of cat muscle spindles with gallamine". Experimental Physiology 79, n.º 3 (1 de mayo de 1994): 365–76. http://dx.doi.org/10.1113/expphysiol.1994.sp003771.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Swanik, C. Buz, Scott M. Lephart, Frank P. Giannantonio y Freddie H. Fu. "Reestablishing Proprioception and Neuromuscular Control in the ACL-Injured Athlete". Journal of Sport Rehabilitation 6, n.º 2 (mayo de 1997): 182–206. http://dx.doi.org/10.1123/jsr.6.2.182.

Texto completo

Resumen

Anterior cruciate ligament (ACL) injury disrupts static and dynamic knee restraints, compromising functional stability. Deafferentation of ACL mechan-oreceptors alters the spinal reflex pathways to motor nerves and muscle spindles in addition to the cortical pathways for conscious and unconscious appreciation of proprioception and kinesthesia. These pathways are required by the feed-forward and feedback neuromuscular control systems to dynamically stabilize joints. Feed-forward motor control is responsible for preparatory muscle activity, while feedback motor control regulates reactive muscle activity. The level of muscle activation, preparatory or reactive, influences muscular stiffness, thereby providing dynamic restraint for the ACL-deficient athlete. Rehabilitation protocols should incorporate activities that enhance muscle stiffness while encouraging adaptations to peripheral afferents, spinal reflexes, and cortical motor patterns. Four elements crucial for reestablishing neuromuscular control and functional stability are proprioceptive and kinesthetic awareness, dynamic stability, preparatory and reactive muscle characteristics, and conscious and unconscious functional motor patterns.

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Braun, Serge. "Thérapies géniques de l’amyotrophie spinale infantile". médecine/sciences 36, n.º 2 (febrero de 2020): 141–46. http://dx.doi.org/10.1051/medsci/2020011.

Texto completo

Resumen

On convient de dire qu’une génération est nécessaire pour faire émerger une nouvelle famille de médicaments. L’amyotrophie spinale infantile (SMA), après l’élucidation du gène causal en 1995, dispose depuis peu de deux classes innovantes de thérapeutiques : l’administration répétée d’oligonucléotides antisens et l’administration unique d’une thérapie génique par scAAV9-SMN. En s’adressant aux mécanismes génétiques de la maladie, elles en modifient fondamentalement le cours. Ces avancées majeures dans une maladie extrêmement sévère, mortelle souvent avant l’âge de 18 mois dans les formes de type 1 (50 % des malades), ouvrent la voie pour d’autres pathologies graves du système nerveux ou neuromusculaire, et apportent une preuve déterminante de l’efficacité de ces classes nouvelles de produits appelés à s’adresser à de nombreuses maladies génétiques ou acquises. Elles génèrent aussi de nouvelles questions d’ordre scientifique et technologique (capacités limitées de production des quantités nécessaires en thérapie génique) mais également d’ordre éthique (conditions d’accès des malades à ces thérapies innovantes), qui résonnent au-delà de cette seule maladie.

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Sinico, Martine, Guillaume Bassez, Claudine Touboul, Helene Cavé, Armand Vergnaud, Clément Zirah, Jocelyne Fleury-Feith et al. "Excess of Neuromuscular Spindles in a Fetus with Costello Syndrome: A Clinicopathological Report". Pediatric and Developmental Pathology 14, n.º 3 (mayo de 2011): 218–23. http://dx.doi.org/10.2350/09-06-0664-cr.1.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Rodger, J., M. R. Ziman, J. M. Papadimitriou y P. H. Kay. "Pax7 is expressed in the capsules surrounding adult mouse neuromuscular spindles". Biochemistry and Cell Biology 77, n.º 2 (1999): 153–56. http://dx.doi.org/10.1139/bcb-77-2-153.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Harris, R. Luke W., Charles T. Putman, Michelle Rank, Leo Sanelli y David J. Bennett. "Spastic Tail Muscles Recover From Myofiber Atrophy and Myosin Heavy Chain Transformations in Chronic Spinal Rats". Journal of Neurophysiology 97, n.º 2 (febrero de 2007): 1040–51. http://dx.doi.org/10.1152/jn.00622.2006.

Texto completo

Resumen

Without intervention after spinal cord injury (SCI), paralyzed skeletal muscles undergo myofiber atrophy and slow-to-fast myofiber type transformations. We hypothesized that chronic spasticity-associated neuromuscular activity after SCI would promote recovery from such deleterious changes. We examined segmental tail muscles of chronic spinal rats with long-standing tail spasticity (7 mo after sacral spinal cord transection; older chronic spinals), chronic spinal rats that experienced less spasticity early after injury (young chronic spinals), and rats without spasticity after transection and bilateral deafferentation (spinal isolated). These were compared with tail muscles of age-matched normal rats. Using immunohistochemistry, we observed myofiber distributions of 15.9 ± 3.5% type I, 18.7 ± 10.7% type IIA, 60.8 ± 12.6% type IID(X), and 2.3 ± 1.3% type IIB (means ± SD) in young normals, which were not different in older normals. Young chronic spinals demonstrated transformations toward faster myofiber types with decreased type I and increased type IID(X) paralleled by atrophy of all myofiber types compared with young normals. Spinal isolated rats also demonstrated decreased type I myofiber proportions and increased type II myofiber proportions, and severe myofiber atrophy. After 4 mo of complete spasticity (older chronic spinals), myofiber type transformations were reversed, with no significant differences in type I, IIA, IID(X), or IIB proportions compared with age-matched normals. Moreover, after this prolonged spasticity, type I, IIA, and IIB myofibers recovered from atrophy, and type IID(X) myofibers partially recovered. Our results indicate that early after transection or after long-term spinal isolation, relatively inactive tail myofibers atrophy and transform toward faster myofiber types. However, long-term spasticity apparently produces neuromuscular activity that promotes recovery of myofiber types and myofiber sizes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Fulceri, Federica, Francesca Biagioni, Fiona Limanaqi, Carla L. Busceti, Larisa Ryskalin, Paola Lenzi y Francesco Fornai. "Ultrastructural characterization of peripheral denervation in a mouse model of Type III spinal muscular atrophy". Journal of Neural Transmission 128, n.º 6 (17 de mayo de 2021): 771–91. http://dx.doi.org/10.1007/s00702-021-02353-9.

Texto completo

Resumen

AbstractSpinal muscular atrophy (SMA) is a heritable, autosomal recessive neuromuscular disorder characterized by a loss of the survival of motor neurons (SMN) protein, which leads to degeneration of lower motor neurons, and muscle atrophy. Despite SMA being nosographically classified as a motor neuron disease, recent advances indicate that peripheral alterations at the level of the neuromuscular junction (NMJ), involving the muscle, and axons of the sensory-motor system, occur early, and may even precede motor neuron loss. In the present study, we used a mouse model of slow progressive (type III) SMA, whereby the absence of the mouse SMN protein is compensated by the expression of two human genes (heterozygous SMN1A2G, and SMN2). This leads to late disease onset and prolonged survival, which allows for dissecting slow degenerative steps operating early in SMA pathogenesis. In this purely morphological study carried out at transmission electron microscopy, we extend the examination of motor neurons and proximal axons towards peripheral components, including distal axons, muscle fibers, and also muscle spindles. We document remarkable ultrastructural alterations being consistent with early peripheral denervation in SMA, which may shift the ultimate anatomical target in neuromuscular disease from the spinal cord towards the muscle. This concerns mostly mitochondrial alterations within distal axons and muscle, which are quantified here through ultrastructural morphometry. The present study is expected to provide a deeper knowledge of early pathogenic mechanisms in SMA.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Liu, Jing-Xia, Hugh J. Willison y Fatima Pedrosa-Domello¨f. "Immunolocalization of GQ1b and Related Gangliosides in Human Extraocular Neuromuscular Junctions and Muscle Spindles". Investigative Opthalmology & Visual Science 50, n.º 7 (1 de julio de 2009): 3226. http://dx.doi.org/10.1167/iovs.08-3333.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Binder, Marc D. "Symposium Changing perspectives on the functional organization of the segmental motor system". Canadian Journal of Physiology and Pharmacology 64, n.º 4 (1 de abril de 1986): 495–98. http://dx.doi.org/10.1139/y86-080.

Texto completo

Resumen

Results from a wide variety of recent studies on the architecture and innervation of skeletal muscles, the neuromechanical characteristics of motor units, and the properties and spinal reflex actions of muscle proprioceptors present a number of challenges to conventional views of the functional organization of the segmental motor system. To illustrate the nature of these challenges, studies directed toward several specific issues are reviewed. These include the functional subdivision of single muscles into two or more neuromuscular compartments; the patterns of synaptic input from peripheral afferent fibers to motoneurons innervating muscle units of different "type;" and the convergence in the segmental reflex pathways from muscle spindles and tendon organs to motoneurons.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Fattorini, Luigi, Angelo Rodio, Vito E. Pettorossi y Guido M. Filippi. "Is the Focal Muscle Vibration an Effective Motor Conditioning Intervention? A Systematic Review". Journal of Functional Morphology and Kinesiology 6, n.º 2 (28 de abril de 2021): 39. http://dx.doi.org/10.3390/jfmk6020039.

Texto completo

Resumen

Mechanical vibration, applied to single or few muscles, can be a selective stimulus for muscle spindles, able to modify neuromuscular management, inducing short and long-term effects, are now mainly employed in clinic studies. Several studies reported as treatments with focal vibratory (FVT) can influence neuromuscular parameters also in healthy people. However, the application modalities and the consequent effects are remarkably fragmented. This paper aims to review these studies and to characterize the FVT effectiveness on long-term conditional capacities in relation to FVT characteristics. A systematic search of studies published from 1985 to 2020 in English on healthcare databases was performed. Articles had to meet the following criteria: (1) treatment based on a locally applied vibration on muscle belly or tendon; (2) healthy adults involved; (3) outcomes time analysis enduring for more than 24 h. Twelve studies were found, all of them presented an excellent quality score of ≥75%. All selected papers reported positive changes, comparable with traditional long-lasting training effects. Muscle force and power were the most investigated parameters. The after-effects persisted for up to several months. Among the different FV administration modalities, the most effective seems to show a stimulus frequency of ≈100 Hz, repeated more times within three-five days on a voluntary contracted muscle.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Bridwell, Keith H. y Christy Baldus. "Wervelkolomafwijkingen bij patiënten met progressieve flaccide neuromusculaire scoliose (ziekte van Duchenne en spinale spieratrofie)". Stimulus 19, n.º 3 (septiembre de 2000): 233. http://dx.doi.org/10.1007/bf03062794.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Servais, L., S. Quijano-Roy, A. M. Seferian, V. Allamand, C. Baumann, P. Richard, B. Estournet et al. "P.1.21 Congenital muscular dystrophy phenotype with excess of neuromuscular spindles in a 5-year old girl". Neuromuscular Disorders 23, n.º 9-10 (octubre de 2013): 748. http://dx.doi.org/10.1016/j.nmd.2013.06.405.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Bolocan, Anamaria, Susana Quijano-Roy, Andreea M. Seferian, Clarisse Baumann, Valérie Allamand, Pascale Richard, Brigitte Estournet et al. "Congenital muscular dystrophy phenotype with neuromuscular spindles excess in a 5-year-old girl caused by HRAS mutation". Neuromuscular Disorders 24, n.º 11 (noviembre de 2014): 993–98. http://dx.doi.org/10.1016/j.nmd.2014.06.437.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Lemoine, Margaux, Marta Gomez, Lamiae Grimaldi, J. Andoni Urtizberea y Susana Quijano-Roy. "Le registre national SMA France : des résultats déjà encourageants". médecine/sciences 37 (noviembre de 2021): 25–29. http://dx.doi.org/10.1051/medsci/2021187.

Texto completo

Resumen

L’amyotrophie spinale proximale liée au gène SMN1 (SMA) est une maladie neuromusculaire invalidante dont l’histoire naturelle a été sensiblement modifiée ces dernières années du fait de l’apparition de thérapies innovantes. Le registre SMA France a été mis en place en 2020 afin de mieux connaître la pathologie et répondre au besoin de données en vie réelle induit par l’arrivée de ces nouveaux médicaments. Le but est aussi d’essayer d’identifier les meilleures stratégies thérapeutiques et d’améliorer in fine la prise en charge de ces patients. Ce registre a le statut d’entrepôt de données de santé et collecte des informations rétrospectives et prospectives de patients SMA de tous types, génétiquement confirmés, traités ou non par thérapies innovantes, et suivis dans les centres du réseau FILNEMUS. La population-cible est estimée à 1 000 patients, dont la moitié d’âge pédiatrique. Au 1er octobre 2021, 666 patients ont été inclus dans la base (357 enfants et 309 adultes) par 44 des 51 centres spécialisés du réseau neuromusculaire FILNEMUS ayant accepté de participer. Parmi ces patients, 150 étaient de type 1 (22 %), 278 (42 %) de type 2, 232 (35 %) de type 3, et 4 de type 4 (1 %).

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Hung, You-jou y Warren G. Darling. "Shoulder Position Sense During Passive Matching and Active Positioning Tasks in Individuals With Anterior Shoulder Instability". Physical Therapy 92, n.º 4 (1 de abril de 2012): 563–73. http://dx.doi.org/10.2522/ptj.20110236.

Texto completo

Resumen

Abstract Background Altered neuromuscular control due to compromised joint position sense may contribute to recurrent shoulder instability. Objective The purpose of the present study was to examine whether individuals with anterior shoulder instability exhibit larger shoulder position sense errors than those with healthy shoulders in both passive matching and active positioning. Design This was a between-groups study with repeated measures. Methods Ten people with anterior shoulder instability and 15 people with healthy shoulders participated in the study. Shoulder position sense was examined with 3 different protocols (passive motion to remembered shoulder rotation angles and active shoulder abduction and rotation to verbally specified positions) in positions of both mid-range and end-range of motion. Results Participants with unstable shoulders exhibited significantly larger errors (by 1.8° on average) in perception of shoulder position compared with those with healthy shoulders during passive matching. During active positioning, participants with unstable shoulders were able to voluntarily move the shoulder to verbally specified angles as accurately as those with healthy shoulders in both abduction (0.85° difference) and rotation (0.99° difference) tasks. Conclusions Results of this study indicate that people with unstable shoulders can perceive shoulder angles as accurately as people with healthy shoulders in activities with voluntary arm movements. Compared with passive matching, better information from muscle spindles and other sources during voluntary arm movements may compensate for the potential joint position sense deficits after the injury. Therefore, individuals with an unstable shoulder may have adequate neuromuscular control to engage proper protective mechanisms to stabilize the shoulder joint during functional activities.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Henry, Julia M., Nizar Chahin, Yael Shiloh-Malawsky, Zheng Fan y Duygu Selcen. "A rare case of congenital myopathy with excess muscle spindles: expanding the clinical spectrum of HRAS-associated neuromuscular disease". Journal of Neurology 262, n.º 6 (23 de mayo de 2015): 1587–89. http://dx.doi.org/10.1007/s00415-015-7775-7.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Migalkin, N. S., G. N. Filimonova, O. G. Prudnikova y I. N. Mezentsev. "Rare nemaline myopathy (a case report)". Genij Ortopedii 28, n.º 5 (octubre de 2022): 715–19. http://dx.doi.org/10.18019/1028-4427-2022-28-5-715-719.

Texto completo

Resumen

Introduction Nemaline myopathies (NM) are a group of neuromuscular diseases, the distinctive histological feature of which are nemaline rods in myosymplasts. The purpose of this work is to describe the morphology of a rare form of primary nemaline myopathy that progresses in adulthood. Material and methods The surgical material of the paravertebral muscles of a 51-year-old patient with scoliotic deformity at the level of L4-S1, who was repeatedly operated on to correct spinal deformity due to neurological disorders, was studied. Paraffin sections were stained with hematoxylineosin, according to Masson, using the Ptah method, studied using a 3DHISTECH Pannoramic MIDI II BF scanning microscope to digitize preparations using Whole slide imaging technology in two modes: Single layer mode and Extended focus (3DHISTECH, Hungary). Results In the fragments of the altered muscle tissue, filamentous structures of nemaline bodies in myosymplasts were identified, which were located diffusely-dotted throughout the sarcoplasm or formed clusters of various configurations. There was an increased variability in the diameters of muscle fibers, internal nuclei, myosymplasts altered by contraction and with signs of myophagy, patterns of gradual replacement of muscle fibers by adipocytes, massive fatty degeneration of fibers, and fibrosis of the interstitial space. Intramuscular nerve trunks showed signs of complete involution; fibrous perineurium was preserved, and there were single nerve fibers; neuromuscular spindles were distinguished by an enlarged connective tissue capsule. The vessels of the arterial flow had signs of fibrosis and obliteration of the lumen; the vessels of the venous bed were tortuous. Discussion Due to a large number of genes responsible for NM, genetic search can be difficult and is effective only in 50 % of cases. It has been established that nemaline bodies can be distributed diffusely or form clusters of irregular shape, more often subsarcolemmal and characteristic of small fibers. In the presented clinical case, nemaline bodies were observed over the entire area of the fibers and were characteristic of myosymplasts of various sizes. Conclusion The histopathological study of the paravertebral muscles established the neuromuscular nature of the disease, being nemaline myopathy that progressed in adulthood and had not been diagnosed at previous stages of treatment.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Artículos de revistas sobre el tema "Neuromuscular spindle"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros