Stimulation Contractility Gradient of a Neuromuscular Choristoma Within the Sciatic Nerve: 2-Dimensional Operative Video

2018 ◽  
Vol 16 (1) ◽  
pp. E17-E17
Author(s):  
Jonathan J Stone ◽  
Kimberly K Amrami ◽  
Jodi M Carter ◽  
Robert J Spinner
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Nerve Biopsy ◽  
Nerve Lesion ◽  
Institutional Review ◽  
Peripheral Nerve Lesions ◽  
Distal Aspect ◽  
Immunohistochemical Studies ◽  
Human Research Protection

Abstract Neuromuscular choristoma (NMC) is a rare congenital nerve lesion that is classified by the presence of heterotopic muscle fibers intercalated within nerve fascicles.1 The presence of NMC typically causes progressive neuropathy and bony/soft tissue undergrowth, often leading to a shortened atrophic limb.2,3 The typical appearance of NMC on magnetic resonance imaging is an enlarged fusiform nerve that exhibits minimal gadolinium enhancement.4 While there is increasing documentation of pathognomonic clinical and radiographic features for various diffuse fusiform peripheral nerve lesions, nerve biopsy is still occasionally required for some patients given the rarity of these diseases and progressive neuropathic features. The intraoperative appearance of NMC and its unique electrical stimulation properties are quite interesting. Intrafascicular replacement of nerve by skeletal muscle gives the nerve a red beefy color and causes the fascicles to contract with electrical stimulation.5 In this video, we demonstrate the intraoperative appearance and contractile properties of NMC in a 60-yr-old woman with progressive sciatic neuropathy. Histologic and immunohistochemical studies identified a gradient of intralesional mature skeletal muscle within the NMC, with substantially fewer desmin-positive skeletal muscle fibers in the distal aspect. A gradient of contractility with intraoperative stimulation seemed to correlate with this pathology. These findings suggest that the lesional extent of NMC may not be clinically or grossly evident, reflecting a varying distribution of skeletal muscle within the affected nerve. The Mayo Clinic Institutional Review Board Office for Human Research Protection does not require approval for single participant case studies. The subject involved in this study was not identifiable and the general surgical consent form included permission for intraoperative photos and video.

The “KIMWIPE” Effect in Ultra-Thin Cryosections

1985 ◽  
Vol 43 ◽  
pp. 458-459
Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Ice Crystals ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Thin Sections ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried ◽  
Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

scholarly journals Changes in Gene Expression of the MCU Complex Are Induced by Electrical Stimulation in Adult Skeletal Muscle

2021 ◽  
Vol 11 ◽  
Author(s):  
Esteban R. Quezada ◽  
Alexis Díaz-Vegas ◽  
Enrique Jaimovich ◽  
Mariana Casas
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Low Frequency ◽  
Extracellular Atp ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Adult Skeletal Muscle ◽  
Muscle Plasticity

The slow calcium transient triggered by low-frequency electrical stimulation (ES) in adult muscle fibers and regulated by the extracellular ATP/IP3/IP3R pathway has been related to muscle plasticity. A regulation of muscular tropism associated with the MCU has also been described. However, the role of transient cytosolic calcium signals and signaling pathways related to muscle plasticity over the regulation of gene expression of the MCU complex (MCU, MICU1, MICU2, and EMRE) in adult skeletal muscle is completely unknown. In the present work, we show that 270 0.3-ms-long pulses at 20-Hz ES (and not at 90 Hz) transiently decreased the mRNA levels of the MCU complex in mice flexor digitorum brevis isolated muscle fibers. Importantly, when ATP released after 20-Hz ES is hydrolyzed by the enzyme apyrase, the repressor effect of 20 Hz on mRNA levels of the MCU complex is lost. Accordingly, the exposure of muscle fibers to 30 μM exogenous ATP produces the same effect as 20-Hz ES. Moreover, the use of apyrase in resting conditions (without ES) increased mRNA levels of MCU, pointing out the importance of extracellular ATP concentration over MCU mRNA levels. The use of xestospongin B (inhibitor of IP3 receptors) also prevented the decrease of mRNA levels of MCU, MICU1, MICU2, and EMRE mediated by a low-frequency ES. Our results show that the MCU complex can be regulated by electrical stimuli in a frequency-dependent manner. The changes observed in mRNA levels may be related to changes in the mitochondria, associated with the phenotypic transition from a fast- to a slow-type muscle, according to the described effect of this stimulation frequency on muscle phenotype. The decrease in mRNA levels of the MCU complex by exogenous ATP and the increase in MCU levels when basal ATP is reduced with the enzyme apyrase indicate that extracellular ATP may be a regulator of the MCU complex. Moreover, our results suggest that this regulation is part of the axes linking low-frequency stimulation with ATP/IP3/IP3R.

scholarly journals Activity-dependent nuclear translocation and intranuclear distribution of NFATc in adult skeletal muscle fibers

2001 ◽  
Vol 155 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Yewei Liu ◽  
Zoltán Cseresnyés ◽  
William R. Randall ◽  
Martin F. Schneider
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Nuclear Translocation ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Adult Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Slow Twitch ◽  
Nuclear Foci ◽  
Fast Twitch

TTranscription factor nuclear factor of activated T cells NFATc (NFATc1, NFAT2) may contribute to slow-twitch skeletal muscle fiber type–specific gene expression. Green fluorescence protein (GFP) or FLAG fusion proteins of either wild-type or constitutively active mutant NFATc [NFATc(S→A)] were expressed in cultured adult mouse skeletal muscle fibers from flexor digitorum brevis (predominantly fast-twitch). Unstimulated fibers expressing NFATc(S→A) exhibited a distinct intranuclear pattern of NFATc foci. In unstimulated fibers expressing NFATc–GFP, fluorescence was localized at the sarcomeric z-lines and absent from nuclei. Electrical stimulation using activity patterns typical of slow-twitch muscle, either continuously at 10 Hz or in 5-s trains at 10 Hz every 50 s, caused cyclosporin A–sensitive appearance of fluorescent foci of NFATc–GFP in all nuclei. Fluorescence of nuclear foci increased during the first hour of stimulation and then remained constant during a second hour of stimulation. Kinase inhibitors and ionomycin caused appearance of nuclear foci of NFATc–GFP without electrical stimulation. Nuclear translocation of NFATc–GFP did not occur with either continuous 1 Hz stimulation or with the fast-twitch fiber activity pattern of 0.1-s trains at 50 Hz every 50 s. The stimulation pattern–dependent nuclear translocation of NFATc demonstrated here could thus contribute to fast-twitch to slow-twitch fiber type transformation.

scholarly journals Activity- and Calcineurin-independent Nuclear Shuttling of NFATc1, but Not NFATc3, in Adult Skeletal Muscle Fibers

2006 ◽  
Vol 17 (4) ◽  
pp. 1570-1582 ◽  
Author(s):  
Tiansheng Shen ◽  
Yewei Liu ◽  
Zoltán Cseresnyés ◽  
Arie Hawkins ◽  
William R. Randall ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Nuclear Export ◽  
Muscle Fibers ◽  
Nuclear Accumulation ◽  
Leptomycin B ◽  
Adult Skeletal Muscle ◽  
Casein Kinase 1 ◽  
Nuclear Uptake ◽  
Skeletal Muscle Fibers

The transcription factor NFATc1 may be involved in slow skeletal muscle gene expression. NFATc1 translocates from cytoplasm to nuclei during slow fiber type electrical stimulation of skeletal muscle fibers because of activation of the Ca2+-dependent phosphatase calcineurin, resulting in nuclear factor of activated T-cells (NFAT) dephosphorylation and consequent exposure of its nuclear localization signal. Here, we find that unstimulated adult skeletal muscle fibers exhibit a previously unanticipated nucleocytoplasmic shuttling of NFATc1 without appreciable nuclear accumulation. In resting fibers, the nuclear export inhibitor leptomycin B caused nuclear accumulation of NFATc1 (but not of isoform NFATc3) and formation of NFATc1 intranuclear bodies independent of calcineurin. The rate of nuclear uptake of NFATc1 was 4.6 times lower in resting fibers exposed to leptomycin B than during electrical stimulation. Inhibitors of glycogen synthase kinase and protein kinase A or of casein kinase 1 slowed the decay of nuclear NFATc1 after electrical stimulation, but they did not cause NFATc1 nuclear uptake in unstimulated fibers. We propose that two nuclear translocation pathways, one pathway mediated by calcineurin activation and NFAT dephosphorylation and the other pathway independent of calcineurin and possibly independent of NFAT dephosphorylation, determine the distribution of NFATc1 between cytoplasm and nuclei in adult skeletal muscle.

Quantitative x-ray elemental imaging in stimulated single intact skeletal muscle fibers: The fate of calcium in the presence of ryanodine

1988 ◽  
Vol 46 ◽  
pp. 90-91
Author(s):  
J. Sommer ◽  
P. Ingram ◽  
A. LeFurgey ◽  
R. Nassar ◽  
T. High
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Time Course ◽  
Imaging System ◽  
Quantitative Imaging ◽  
Muscle Fibers ◽  
Frog Skeletal Muscle ◽  
X Ray ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried

We are involved in a continuing series of experiments aimed at a complete description,in terms of morphology and quantitative topochemistry, of the time course of spatial distributions of physiologically important elements during excitation-contraction coupling (ECC) at different time intervals (fractions of msec) following electrical stimulation of single, intact frog skeletal muscle fibers. In this present study wg report such distributions for Ca after 1,2 and 3 min of electrical stimulation in the presence of 2x10-4 M ryanodine, an alkaloid that, in time, causes irreversible muscle contractures.Single, intact frog skeletal muscle fibers were quick-frozen, cryosectioned, freeze-substituted and in one case freeze-fractured. The freeze-dried cryosections were subjected to electron probe X-ray microanalysis (EPXMA) in a JEOL 1200EX analytical electron microscope equipped with a Tracor Northern X-ray detector and a fully quantitative imaging system. Both, 64/64 pixel images (ambient temp.), and small raster probes (cold stage,-115 °C) for better statistics, were obtained, each from the same section.

scholarly journals Elevated nuclear Foxo1 suppresses excitability of skeletal muscle fibers

2013 ◽  
Vol 305 (6) ◽  
pp. C643-C653 ◽  
Author(s):  
Erick O. Hernández-Ochoa ◽  
Tova Neustadt Schachter ◽  
Martin F. Schneider
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Atrophy ◽  
Action Potentials ◽  
Muscle Fibers ◽  
Calcium Transients ◽  
Skeletal Muscle Atrophy ◽  
Nuclear Activity ◽  
Ec Coupling ◽  
Skeletal Muscle Fibers

Forkhead box O 1 (Foxo1) controls the expression of proteins that carry out processes leading to skeletal muscle atrophy, making Foxo1 of therapeutic interest in conditions of muscle wasting. The transcription of Foxo1-regulated proteins is dependent on the translocation of Foxo1 to the nucleus, which can be repressed by insulin-like growth factor-1 (IGF-1) treatment. The role of Foxo1 in muscle atrophy has been explored at length, but whether Foxo1 nuclear activity affects skeletal muscle excitation-contraction (EC) coupling has not yet been examined. Here, we use cultured adult mouse skeletal muscle fibers to investigate the effects of Foxo1 overexpression on EC coupling. Fibers expressing Foxo1-green fluorescent protein (GFP) exhibit an inability to contract, impaired propagation of action potentials, and ablation of calcium transients in response to electrical stimulation compared with fibers expressing GFP alone. Evaluation of the transverse (T)-tubule system morphology, the membranous system involved in the radial propagation of the action potential, revealed an intact T-tubule network in fibers overexpressing Foxo1-GFP. Interestingly, long-term IGF-1 treatment of Foxo1-GFP fibers, which maintains Foxo1-GFP outside the nucleus, prevented the loss of normal calcium transients, indicating that Foxo1 translocation and the atrogenes it regulates affect the expression of proteins involved in the generation and/or propagation of action potentials. A reduction in the sodium channel Nav1.4 expression in fibers overexpressing Foxo1-GFP was also observed in the absence of IGF-1. We conclude that increased nuclear activity of Foxo1 prevents the normal muscle responses to electrical stimulation and that this indicates a novel capability of Foxo1 to disable the functional activity of skeletal muscle.

scholarly journals Gerta Vrbová, a guide and a friend for a generation of neuro-myologists – Her scientific legacies and relations with colleagues

2021 ◽  
Author(s):  
Ugo Carraro
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Neuromuscular Disorders ◽  
Muscle Fibers ◽  
Low Frequency ◽  
Scientific Heritage ◽  
Adult Muscle ◽  
Skeletal Muscle Fibers ◽  
Different Types ◽  
The Many

Gerta Sidonová - Vrbová, (Trnava, Slovakia, November 28, 1926 - London, UK, October 2, 2020) has been a key neuroscientist, who for almost half a century has contributed important findings and hypotheses on the relationships between motoneurons and skeletal muscle fibers, in particular on the differentiation and extent of plasticity of the peculiar characteristics of the different types of fibers present in mammalian muscles. This issue, Ejtm 31 (1), 2021, opens with the personal obituary authored by Dirk Pette, who remember his lifelong collaboration with Gerta, describing the many molecular and metabolic events that occur by changing the pattern of activation of adult muscle fibers through neuromuscular low frequency electrical stimulation. To honor the many scientific legacies of Gerta Vrbová and her impact on a generation of researchers studying myology and managements of neuromuscular disorders I add here additional examples of Gerta’s scientific heritage and of her relations with colleagues.

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