bluuebunny/crossref_metadata_2025 huggingface dataset:
Leakage of carbonic anhydrase III from normal and denervated rat skeletal muscle following contractile activity
Authors: Ashmark Håkan , Wistrand Per J.
Published: January 2005

Skeletal muscle extracellular carbonic anhydrase III was investigated in anesthetized rats by a microdialysis technique. A small dialysis probe was inserted into the tibialis anterior (TA) muscle and perfused continuously. Perfusates were collected before and during muscle contraction, induced by electrical stimulation of the muscle or of the sciatic nerve. In the perfusate of resting normal and denervated muscle, the concentration of CA III was 10 to 12 ng/mL, as measured by a radiommunosorbent technique. During contractile acitvity, the concentrations of CA III increased markedly in hte normal and denervated muscle. A TA muscle suspended in physiological saline behaved similarly, even though the leakage before and during contrafction was higher than in vivo. The results show that skeletal muscle leaks CA III both in vivo and in vitro, a leakage which was markedly increased by contractile activity. The microdialysis technique should also be useful in humans to study the efflux of various proteins from different kinds of diseased or fatigued muscles.
Reciprocal changes in myosin isoform mRNAs of rabit skeletal muscle in response to the initiation and cessation of chronic electrical stimulation
Authors: Brownson Carol , Little Pauline , Jarvis Jonathan C. , Salmons Stanley
Published: January 2005

Changes in myosin heavy chain (MHC) mRNAs were studied in rabbit fasttwitch muscles during continuous electrical stimulation at 10 Hz for periods up to 3 weeks, and during the first 12 days of the recovery process that followed cessation of 6 weeks' stimulation. Two cDNA probes were used to detect MHC mRNAs specific to fast‐ and slow‐twitch skeletal muscle in RNase protection assays and Northern‐ and slot‐blot analyses. The isolation and base sequence of one of these probes, corresponding to the MHC gene expressed in soleus (slow‐twitch), is described. At an early stage of the response to stimulation, fast MHC mRNA was replaced by slow MHC mRNA. During recovery, this process occurred in reverse but took longer. The time course of recovery was slightly faster in tibialis anterior than in extensor digitorum longus. The changes in mRNAs during both stimulation and recovery reflected changes in the corresponding muscle proteins.
Transcranial magnetic stimulation of the facial nerve: Intraoperative study on the effect of stimulus parameters on the excitation site in man
Authors: Schmid Urs D. , Møller Aage R. , Schmid Judith
Published: January 2005

Magnetic stimulation (magStim) of the intracranial facial nerve is performed in clinical and research settings, but the activation site is a matter of controversy. Latencies of nasalis muscle responses to magStim were, therefore, compared with those obtained by direct electrical stimulation of the facial nerve (a) at the root exit zone (REZ); (b) at the porus of the facial canal; and (c) in the stylomastoid fossa during microvascular decompression operations in the cerebellopontine angle (CPA). Measurements of latencies of the nasalis muscle response, obtained while the stimulating coil was placed over the parieto‐occipital area of the scalp, indicated that it was the labryinthine segment of the facial canal, 5 to 16 mm distal to the CPA, that was activated. This would be in agreement with studies of physical models reported in the literature that showed (a) the strength of the electrical current generated by a magnetic field is particularly high close to a nerve foramen; and (b) excitation to magStim is most likely to occur where the induced electrical field changes rapidly over distance, i.e., at anatomical boundaries between media of high and low specific resistance. These characteristics are found at the end of the labyrinthine segment of the facial canal, where the facial nerve leaves the low‐resistance cerebrospinal fluid and enters the high‐resistance petrous bone. The site of neural excitation is robust and unaffected by stimulus intensity and current direction within a wide range, or by large changes in location of the coil. The practical implication of this study is that transcranial magStim does not reflect nerve conduction in segments of the facial nerve that are located proximal to the facial canal, which accounts for about 40% of the nerve length between the REZ and the stylomastoid fossa.
Twitch and tetanus in mdx mouse muscle
Authors: Quinlan John G. , Johnson Scott R. , McKee Mari K. , Lyden Sean P.
Published: January 2005

We compared mdx and C57BL10 anterior tibial muscle force in situ (single pulse, multiple pulse, staircase, posttetanic potentiation, and fatiguing stimulation patterns) to define muscle strength, physiology, and fatigue resistance. The relatively hypertrophied mdx muscle showed: reduced strength (N/cm2), an increased twitch‐tetanus ratio, and resistance to postfatigue twitch slowing. These differences implicate altered mdx calcium regulation, and emphasize the importance of measuring both muscle function and morphology in mdx treatment trials. © 1992 John Wiley & Sons, Inc.
Effects of phenytoin in two myotonic horses with hyperkalemic periodic paralysis
Authors: Beech Jill , Fletcher Jeffrey E. , Tripolitis Linda , Lindborg Sue
Published: January 2005

The effects of phenytoin treatment were evaluated in 2 myotonic horses with hyperkalemic periodic paralysis (HPP). Phenytoin treatment abolished the clinical signs of muscle fasciculations following oral potassium challenge and decreased or abolished repetitive firing and myotonic discharges found on electromyographic examination. In both horses, an abnormally low threshold for calcium‐induced calcium release was measured in heavy sarcoplasmic reticulum fractions from skeletal muscle, and this threshold increased with phenytoin treatment. Results suggest phenytoin is useful in modifying disordered ion regulation in the sarcolemma and sarcoplasmic reticulum of skeletal muscle in equine hyperkalemic periodic paralysis. © 1992 John Wiley & Sons, Inc.
The spectrum of concentric macro EMG correlations. Part I. Normal subjects
Authors: Bauermeister Wolfgang , Jabre Joe F.
Published: January 2005

Using a concentric macro electrode, both the concentric and macro action potentials of a motor unit were analyzed for duration, area, and amplitude. Eighty‐six different motor units were analyzed from the tibialis anterior muscle in 10 normal subjects. The aim of this work was to compare concentric and macro action potential measurements of the same motor unit. The study revealed significant correlations between concentric and macro samples, with the concentric potential's area correlating better with the macro potential than its amplitude. This shows that the 10 to 15 muscle fibers studied by the concentric electrode serve as a good sample of the motor unit as a whole. We briefly review the technique used in concentric macro EMG, as well as describe the methods used for collecting and comparing both concentric and macro action potentials. © 1992 John Wiley & Sons, Inc.
Inorganic mercury is transported from muscular nerve terminals to spinal and brainstem motoneurons
Authors: Arvidson Björn
Published: January 2005

The distribution of mercury within the brainstem and spinal cord of mice was investigated with the autometallographic technique after intramuscular administration of a single dose of mercuric mercury (HgCl2). Deposits of mercury were localized to motor neurons of the spinal cord and to to brainstem motor nuclei; i.e., neurons with their peripheral projections outside the blood‐brain barrier. Unilateral ligation of the hypoglossal nerve prior to the injection of HgCl2 prevented the accumulation of mercury deposits in the ipsilateral hypoglossal nucleus. The selective accumulation of mercury in spinal and brainstem motoneurons is most probably due to a leakage of metal‐protein complexes form capillaries in muscle into myoneural junctions, followed by uptake into nerve terminals and retrograde axonal transport. The possible link between this process and the developmentof motor neuron degeneration in ALS is discussed. © 1992 John Wiley & Sons, Inc.
An augmented computer model of motor unit reorganization in neurogenic diseases of skeletal muscle
Authors: Lester James M. , Soule Norman W. , Bradley Walter G. , Brenner John F.
Published: January 2005

A computer model of denervation and complete reinnervation in skeletal muscle was originally developed for the purpose of furthering an understanding of the underlying mechanisms of motor unit reorganization in neurogenic diseases. We now describe its successor, a computer model for investigating different rates of denervation and reinnervation, as well as incomplete reinnervation. The new model introduces the concept of permanent denervation and features enhanced interactive control over the distribution of motor unit centers and additional measures of dispersion and co‐dispersion of muscle fibers. The use of this model for investigating pathophysiologically significant issues in denervating diseases is illustrated pathophysiologically significant issues in denervating diseases is illustrated with five different sets of parameters. These simulate some of the processes that may be operational in chronic spinal muscular atrophy, amyotrophic lateral sclerosis, and progressive postpolio muscular dystrophy. The enhanced model will allow in‐depth analysis of the influence of hypothesized pathophysiological processes on clinical, electrophysiological and pathological outcomes in human disease. © 1993 John Wiley & Sons, Inc.
Postmortem examination of relapsing acute Guillain–Barre syndrome
Authors: Al‐Hakim Mazen , Cohen Mark , Daroff Robert B.
Published: January 2005

We report a patient who had six episodes of acute Guillain—Barre syndrome during his life. He is the fifth such case with postmortem analysis. © 1993 John Wiley & Sons, Inc.
Single fiber EMG in a congenital myasthenic syndrome associated with facial malformations
Authors: Sadeh Menachem , Blatt Ilan , Goldhammer Yochanan
Published: January 2005

Six patients with a newly described genetic syndrome in Iraqi and Iranian Jews of congenital myasthenia associated with facial malformations were studied with voluntary and stimulation single fiber EMG (SFEMG). Voluntary SFEMG revealed abnormal jitter in all patients in both extensor digitorum communis (EDC) and orbicularis oculi (OOC) muscles, though much smaller in the clinically unaffected EDC. SFEMG study of OOC muscle by axonal stimulation at rates from 1 to 48 Hz showed the most increased jitter at the highest stimulation frequencies in the majority of end‐plates, one‐third of which showed maximal jitter at intermediate rates. These results may suggest a postsynaptic abnormality as the underlying cause for the neuromuscular transmission defect, and demonstrate the usefulness of SFEMG in the diagnosis of congenital myasthenia. © 1993 John Wiley & Sons, Inc.
Factors affecting muscle fiber transformation in cross. Reinnervated muscle
Authors: Thomas P. E. , Rantunga K. W.
Published: January 2005

Nerves of two fast muscles [peroneus longus (PL) and extensor digitorum longus (EDL)], having different type 2 muscle fiber compositions, were used to cross‐reinnervate the slow soleus muscle in the rat. Contraction characteristics, histochemical muscle fiber type compsotions and myosin heavy chain (MHC) isoform compositions were determined for the reinnervated muscles. Shortening velocity increased in soleus muscles crossreinnervated with EDL nerve [X‐SOL(EDL)] but not in muscles cross‐reinnervated with PL nerve [X‐SOL(PL)]. Type 2A MHC isoform content was increased in X‐SOL(EDL) but not in X‐SOL(PL), where MHC isoform composition remained similar to normal soleus. The complement of type 1 (slow) muscle fibers was reduced and that of type 2 (fast) fibers increased in both types of X‐SOL muscle, but this change was significantly greater in X‐SOL(EDL); the majority of the type 2 fibers in X‐SOL muscles were of type 2A. Results show that “the type 2 composition” of the reinnervating motoneuron pool is an important factor in determining the transformation of a target slow muscle after cross‐reinnervation. © 1993 John Wiley & Sons, Inc.
Muscle ultrasonography and computed tomography in elderly trained and untrained women
Authors: Sipilä Sarianna , Suominen Harri
Published: January 2005

Ultrasonography (US) and computed tomography (CT) were compared in studying the associations between long‐term physical training and quadriceps muscle mass and structure in female athletes and controls, aged 66–85 years. Muscle cross‐sectional area (CSA) measured using US correlated highly with that measured using CT, but the latter technique yielded 30% higher values on average. The echo intensity of the fasciae and bone measured by US correlated positively with the mean radiological density and negatively with the relative proportion of fat obtained from CT. Low intramuscular echo intensity was accompanied by high muscle density and low relative proportion of fat. The athletes had larger quadriceps CSA and more discerned fasciae and connective tissue septa but less fat than the controls. The results indicate that US and CT both are useful methods in comparing muscle mass and structure in elderly trained and untrained women. © 1993 John Wiley & Sons, Inc.
Metabolic changes in reflex sympathetic dystrophy: A 31P NMR spectroscopy study
Authors: Heerschap Arend , Hollander Jan A. Den , Reynen Han , Goris R. Jan A.
Published: January 2005

The lower leg skeletal muscles of 11 patients affected by reflex sympathetic dystrophy were investigated at rest by 31P nuclear magnetic resonance spectroscopy at a fieldstrength of 1.5 T. The results were compared with similar investigations of unaffected lower leg muscles of patients and volunteers. A significant increase was observed for the average tissue pH of the muscles of affected legs as deduced from the chemical shift of the resonance for inorganic phosphate. The average inorganic phosphate/phosphocreatine ratio of these muscles was also increased. The impairment of high energy phosphate metabolism, as deduced from the NMR data, may be caused by cellular hypoxia or diminished oxygen utilization, which would agree with previous findings that oxygen extraction is reduced in extremities affected by reflex sympathetic dystrophy. © 1993 John Wiley & Sons, Inc.
Multiple descending corticospinal volleys demonstrated by changes of the wrist flexor H‐reflex to magnetic motor cortex stimulation in intact human subjects
Authors: van der Linden Chris , Bruggeman Richard
Published: January 2005

To study noninvasively multiple descending volleys on alpha motoneurons, we used a 30–50% maximum H‐reflex in the wrist flexor muscle conditioned by a subthreshold magnetic stimulus of the contralateral motor cortex as a parameter of motoneuronal excitability in seven neurologically healthy subjects. The time interval of the median nerve (test) stimulus and the magnetic (conditioning) stimulus was varied. In all subjects the conditioned H‐reflex significantly (P < 0.05) enhanced at conditioning‐test intervals between ‐1 ms and +10 ms. Superimposed on the overall facilitation there were at least two short duration periods of enhanced facilitation in all but one subject. These periods were separated by 2–4 ms and suggest increased excitability at the alpha motoneuronal pool brought on by the descending volleys. We conclude that with subthreshold magnetic cortical stimuli it is possible to produce multiple descending corticospinal volleys, which probably represent descending I waves. This should be taken into account when analyzing motor evoked potentials (MEPs) in clinical studies. © 1993 John Wiley & Sons, Inc.
Comparison of sympathetic sudomotor and skin responses in alcoholic neuropathy
Authors: Navarro Xavier , Miralles Ramon , Espadaler Josep M. , Rubiés‐Prat Juan
Published: January 2005

We evaluated sympathetic sudomotor and parasympathetic vagal function in 30 chronic alcoholic patients and 28 control subjects by means of silicone imprints, sympathetic skin responses (SSR), and cardiorespiratory reflex tests. Mean values from alcoholic patients were significantly lower than those from control subjects for all tests. The number of secreting sweat glands (SGN) was below normal in the foot of 18 patients, and in the hand of 7 patients; 16 patients had absent SSR on the sole, and 4 on the palm. Only two patients had both test results abnormal on the hand and 10 on the foot. The SGN did not correlate with the amplitude of the SSR in the subjects studied. There was no clear correlation of abnormalities found in cardiorespiratory tests and sympathetic tests. Abnormalities in sensory nerve conduction were associated with absent SSR, but not with decreased SGN. The silicone mold technique is a more specific test to detect abnormalities in sympathetic efferent fibers, as SSR may be influenced by sensory afferent fiber involvement. © 1993 John Wiley & Sons, Inc.
Purification of human muscle satellite cells by flow cytometry
Authors: Baroffio Anne , Aubry Jean‐Pierre , Kaelin Andre , Krause Ryoko M. , Hamann Martine , Bader Charles R.
Published: January 2005

To purify satellite cells directly from human muscle biopsies, we have developed a method based on size separation of dissociated cells by flow cytometry. Immediately after tryptic dissociation of human muscle biopsies and elimination of erythrocytes, microscopic observation and flow cytometry analysis of cell suspensions revealed two populations of cells differing in size and nucleocytoplasmic ratio. Clonal cultures of these two cell types with a manual procedure demonstrated that only the small cells were myogenic satellite cells. Flow cytometry‐sorting and analysis of the small cell population showed that (1) all sorted cells contained desmin immediately after dissociation and plating; (2) more than 98% of the cells expressed the 5.1.H11 epitope after 2 weeks of proliferation in culture; and (3) 90% of the sorted cells were able to form myotubes when cultivated at low density or in clonal cultures. Thus, human muscle satellite cells can be directly purified from human muscle samples using flow cytometry. © 1993 John Wiley & Soncs, Inc.
The rigid spine syndrome: A vacuolar variant
Authors: Lotz Barend P. , Stübgen Joeerg‐P
Published: January 2005

The rigid spine syndrome encompasses a number of disorders. We report 7 males and 2 females with this phenotype and a single, not previously reported, nosology. The salient muscle histological features were autophagic vacuoles, vacuoles containing capillaries, muscle spindle swelling, and type l fiber predominance. Disease onset was before age 6 years in all patients. Inheritance was probably autosomal recessive as siblings were affected in two families. Pulmonary function tests showed severely restricted ventilation, 3 patients required nocturnal ventilatory assistance, 2 patients had cor pulmonale, and mitral valve abnormalities were common. Serum CK levels were moderately elevated. EMG studies showed evidence of an active, chronic myopathy. The mean motor unit potential duration was statistically significantly shorter compared to controls in the triceps and anterior tibial muscles. Single fiber EMG “jitter” and evoked potential studies were normal. © 1993 John Wiley & Soncs, Inc.
Analysis of anticholinesterase‐induced neuromuscular transmission failure
Authors: Maselli Ricardo A. , Leung Cynthia
Published: January 2005

To define the underlying mechanism of neuromuscular transmission failure induced by anticholinesterases, we simultaneously performed surface recordings of compound muscle action potentials (CMAPs) and intracellular recordings of miniature end‐plate potentials (MEPPs), miniature end‐plate current (MEPCs), and end‐plate potential (EPPs) in rat diaphragms exposed in vitro to 1 × 10−4 to 2 × 10−2 mmol/L neostigmine methylsulfate. At low concentrations of neostigmine, repetitive stimulation of the phrenic nerve resulted in decrement followed by complete recuperation of CMAP amplitudes. This bimodal pattern was associated with maximal end‐plate depolarization at the beginning of the stimulation period, increased MEPP amplitudes, and prolonged time constants of MEPC decays. Higher concentrations of neostigmine resulted in a unimodal decline of amplitudes of CMAPs and EPPS, reduced MEPP amplitudes, and a double exponential time course of MEPC decays. These results indicate that low concentrations of anticholinesterases impaired neuromuscular transmission by producing transient depolarization of the end‐plate region. Higher concentrations induced desensitization and direct blockade of the end‐plate receptor channel, probably in its open conformation. © 1993 John Wiley & Soncs, Inc.
Long‐term follow‐up of patients with Duchenne muscular dystrophy receiving ventilatory support
Authors: Fukunaga Hidetoshi , Okubo Ryuichi , Moritoyo Takashi , Kawashima Nozomu , Osame Mitsuhiro
Published: January 2005

We, retrospectively, examined the clinical course, decline in pulmonary function, and requirements for ventilatory assistance in 54 patients with Duchenne‐type muscular dystrophy (DMD) who were followed in the muscle disease ward of the National Hospital in Kagoshima, Japan, over the past 20 years. The percentage of the predicted vital capacity (%VC) declined in relation to age and stage of disease. Most patients required assisted ventilation when the %VC fell below 10%. Twenty patients were treated with a negative pressure chest respirator. Six of these died at the mean age of 23.2 years after being on the respirator for a mean period of 18 months. Fourteen patients are surviving at a mean age of 23.5 years after being on the respirator for a mean period of 39 months. © 1993 John Wiley & Soncs, Inc.
Acute morphologic changes in orbicularis oculi muscle after doxorubicin injection into the eyelid
Authors: McLoon Linda Kirschen , Luo Xing Xing , Wirtschafter Jonathan
Published: January 2005

This study attempts to gain a better understanding of the primary cause of doxorubicin myotoxicity to aid in the development of a protocol to increase its effectiveness in treating muscle spasm diseases. The time course of acute injury to the orbicularis oculi muscle after injection of doxorubicin into the eyelids of rabbits was examined. The effects of doxorubicin injection were immediate and dramatic. Within 5 minutes, the muscle cells in the eyelids showed signs of myofibrillar dissolution. This process continued for the first 24 hours, with a marked decrease in the total number of myofibers by 1 hour after drug treatment. By 4 days after doxorubicin injection, most of the treated muscle had a more normal morphology, although some ongoing myofibrillar dissolution was present. There was evidence for a limited amount of muscle regeneration. Three levels of injury were seen: a severe, irreversible injury in the majority of the myofibers; a mild, reversible injury in a subset of the fibers; and a group of myofibers apparently uninjured as a result of doxorubicin treatment. Doxorubicin toxicity in skeletal muscle is of rapid onset. Understanding the primary cause and acute changes in doxorubicin myotoxicity may accelerate the development of improved protocols to increase the effectiveness of doxorubicin in treating muscle spasm diseases.
Na+ currents near and away from endplates on human fast and slow twitch muscle fibers
Authors: Ruff Robert L. , Whittlesey Diana
Published: January 2005

Fast and slow twitch muscle fibers have distinct contractile properties. Here we determined that membrane excitability also varies with fiber type. Na+ currents (INA) were studied with the loose‐patch voltage clamp technique on 29 histochemically classified human intercostal skeletal muscle fibers at the endplate border and <200 μm from the endplate (extrajunctional). Fast and slow twitch fibers showed slow inactivation of endplate border and extrajunctional INA and had increased INA at the endplate border compared to extrajunctional membrane. The voltage dependencies of INA were similar on the endplate border and extrajunctional membrane, which suggests thatboth regions have physiclogically similar channels. Fast twitch fibers had larger INA on the endplate border and extrajunctional membrane and manifest fast and slow inactivation of INA at more negative potentials than slow twitch fibers. For normal muscle, the differences between INA on fast and slow twitch fibers might: (1) enable fast twitch fibers to operate at high firing frequencies for brief periods; and (2) enable slow twitch fibers to operate at low firing frequencies for prolonged times. Disorders of skeletal membrane excitability, such as the periodic paralyses and myotonias, may impact fast and slow twitch fibers differently due to the distinctive Na+ channel properties of each fiber type. © 1993 John Wiley & Sons, Inc.
Invited Review. The potential for gene therapy in duchenne muscular dystrophy and other genetic muscle diseases
Authors: Karpati George , Acsadi Gyula
Published: January 2005

Dystrophin cDNAs have been introduced into skeletal muscle fibers of dystrophin‐deficient mice (mdx) through direct DNA injection in plasmid expression vectors and by replication‐defective recombinant adenovirus vectors. The introduced genes appear to protect those muscle fibers from necrosis in which they become expressed. By direct injection of dystrophin cDNA in plasmid expression vector, only 1–2% of adult mdx muscle fibers of the injected muscle expressed dystrophin. On the other hand, by recombinant adenovirus injection into very young mdx muscle, a better efficiency has been reported. We have discussed several putative and proven factors that may contribute to the thus far demonstrated relatively low efficiency of dystrophin gene transfer. These include poor uptake of gene constructs by muscle fibers, degradation of the injected DNA, and poor access of gene constructs to the nuclear compartment. Neutralization or elimination of these factors could improve the efficiency of gene transfer so that it might, in the future, qualify as an effective therapy for DMD and some other genetic diseases of muscle.© 1993 John Wiley & Sons, Inc.
Muscle cramp as the result of impaired gaba function—an electrophysiological and pharmacological observation
Authors: Obi T. , Mizoguchi K. , Matsuoka H. , Takatsu M. , Nishimura Y.
Published: January 2005

We investigated the mechanism of cramps in 2 patients: a 48‐year‐old man with bulbospinal neuronopathy, and a 46‐year‐old man with amyotrophic lateral sclerosis. Cramps were quite easily induced by volitional exertion and high‐frequency stimulation of the peripheral nerves. When an ulnar nerve was blocked with lidocaine at the elbow, no cramp was induced despite the application of high‐frequency stimulation at the wrist. Diazepam (GABAA agonist) was effective in the first patient and baclofen (GABAB agonist) in the second, with no cramps induced in spite of increasing stimulation intensity. Impairment of interneurons mediated by GABA as the neurotransmitter is thought to be involved in the mechanism of the cramps. © 1993 John Wiley & Sons, Inc.
Acetylcholine receptor subunit gene expression in thymic tissue
Authors: Kaminski Henry J. , Fenstermaker Robert A. , Abdul‐Karim Fadi W. , Clayman Julie , Ruff Robert L.
Published: January 2005

It is controversial whether acetylcholine receptors (AChR) or AChR‐like proteins exist in human thymus. To evaluate this question we isolated RNA from paraffin‐embedded thymic tissue of 5 myasthenics and 5 nonmyasthenics. RNA was subjected to reverse transcription followed by polymerase chain reaction (RT‐PCR) using primers specific for β‐actin, subunits of the fetal‐ and adult‐type AChR, and Myf‐4, a gene product which regulates AChR expression in muscle. β‐Actin transcripts were identified in specimens from 8 of 10 patients. In these 8 patients α‐and ε‐subunit transcripts were identified. Presence of these transcripts did not correlate with thymic pathology or clinical presentation. No γ‐subunit (specific for the fetal‐type AChR) or Myf‐4 transcripts were found. Our results indicate that mRNA for subunits of the adult‐type AChR are expressed in thymic tissue by mechanisms not involving Myf‐4. AChR subunits in pathological thymus may provide a target for immune attack in MG. However, as AChR subunits were found in thymus tissue from myasthenics and nonmyasthenics, the presence of AChR subunits in the thymus alone is not sufficient to produce myasthenia gravis. © 1993 John Wiley & Sons, Inc.
Literature review of the usefulness of nerve conduction studies and electromyography for the evaluation of patients with carpal tunnel syndrome
Authors: AAEM Quality Assurance Committee  , Jablecki Charles K. , Andary Chair Michael T. , So Yuen T. , Wilkins Dennis E. , Williams Faren H.
Published: January 2005

The sensitivity and specificity of nerve conduction studies (NCS's) and electromyography (EMG) for the diagnosis of carpal tunnel syndrome CTS) were evaluated by a critical review of the literature. With a search of the medical literature in English through May 1991, 165 articles were identified and reviewed on the basis of six criteria of scientific methodology. The findings of 11 articles that met all six criteria and the results of 48 additional studies that met four or five criteria are presented. We concluded that median sensory and motor NCS's are valid and reproducible clinical laboratory studies that confirm a clinical diagnosis of CTS with a high degree of sensitivity and specificity. Clinical practice recommendations are made based on a comparison of the sensitivities of the several different median nerve conduction study (NCS) techniques.
Early appearance of aging phenomenon in the interdigital nerves of the foot
Authors: Lee Kwang W. , Oh Shin J.
Published: January 2005

To test the hypothesis that the interdigital nerves of the foot are the first to be affected by aging, we studied sensory nerve conduction in the nerves of normal subjects between the ages of 10 and 79, using the near‐nerve needle technique. In normal individuals up to the seventh decade we could get sensory CNAPs without any difficulty by 256 averagings. In 10% of the 70–79‐year‐old group we could not obtain those potentials in some digital or interdigital nerves. Between the 10–49‐year‐old and 50–79‐year‐old groups, there was a significant slowing in the sensory NCVs, a significant decline in the amplitude of the sensory CNAPs, and a significant prolongation of the duration of sensory CNAPs for the various interdigital nerves. Thus, our study documented the earlier presence of aging phenomenon in the sensory nerve conduction of the interdigital nerves of the foot compared with the previously reported sensory nerve conduction change with age in the other nerves. We conclude that the “degeneration” of various interdigital nerves of the foot is accelerated from the early 50s on, possibly resulting from the normal aging process. © 1994 John Wiley & Sons, Inc.
Anti‐GM1 antibodies and impaired blood–nerve barrier may interfere with remyelination in multifocal motor neuropathy
Authors: Kaji Ryuji , Hirota Nobuyuki , Oka Nobuyuki , Kohara Nobuo , Watanabe Tetsuya , Nishio Takeshi , Kimura Jun
Published: January 2005

Multifocal motor neuropathy has pure motor manifestation and nonremittent clinical courses. Antiganglioside antibodies, though variable in titers, are characteristically elevated in the majority of these patient. In our cases, pathological findings at the site of conduction block suggested impaired remyelination and disruption of blood–nerve barrier. These findings lead us to postulate that antibodies toward gangliosides or toward unknown antigens containing gangliosides initiate motorspecific demyelination. The lesion, once produced, may persist as a result of impaired remyelination caused by disrupted blood–nerve barrier. The antibodies bound to denuded axons may also interfere with a remyelinative process. If so, antibodies may not always be circulating, thus accounting for variable levels of titers. © 1994 John Wiley & Sons, Inc.
Nerve root hypertrophy in chronic inflammatory demyelinating polyneuropathy
Authors: de Silva Rajith N. , Willison Hugh J. , Doyle David , Weir Andrew I. , Hadley Donald M. , Thomas A. Myfanwy
Published: January 2005

A patient with chronic inflammatory demyelinating polyneuropathy (ClDP) and centrel demyelinating disease is desoribed in whom striking nodular filling defects on multiple lumbar–sacral nerve roots, mimicking neurofibromata, were observed at myelography and magnetic resonance imaging. We suggest that these lesions are secondary to recurrent segmental demyelination and remyelination and that the differential diagnosis of this radiological feature should include CIDP. © 1994 John Wiley & Sons, Inc.
AAEM case report #5: Amyotrophic lateral sclerosis
Authors: Denys Eric H.
Published: January 2005

A 40‐year‐old man presented with a gradual onset of gait unsteadiness and weakness in the arms. The stretch reflexes were normal in the upper extremities but hyperactive in the lower extremities with bilateral Babinski signs. A myelogram revealed a partial obstruction at C‐5–6. Two prior electromyograms, 7 and 5 months prior to admission, reportedly showed positive waves only in two peroneal supplied muscles. Repeat electromyographic testing demonstrated normal nerve conduction velocities and needle electrode abnormalities in upper and lower extremities as well as thoracic paraspinal muscles allowing a diagnosis of amyotrophic lateral sclerosis (ALS). The importance of electromyographic testing in clinically nonaffected areas is stressed as well as its role in patients presenting with upper motor neuron signs. It is the task of the clinical electromyographer to consider other entities in the differential diagnosis, such as a multifocal motor neuropathy with conduction blocks and design the tests accordingly. The role of electromyography in the prediction of the course of ALS by assessing the degree of reinnervation is discussed. This will become increasingly important in the design of treatment trials.
Acute necrotizing myopathy of intensive care: Electrophysiological studies
Authors: Zochodne Douglas W. , Ramsay David A. , Saly Viera , Shelley Steven , Moffatt Susan
Published: January 2005

A series of recent reports have identified cases of a quadriplegic myopathy characterized by myofiber necrosis and loss of myosin filaments associated with the use of nondepolarizing muscle blocking agents and glucocorticoids. We report electrophysiological findings in 7 intensive care unit patients who developed evidence of an acute myopathy in association with the use of nondepolarizing muscle blocking agents. Several important features were identified: (i) a neuromuscular transmission deficit was observed in 3 patients up to 7 days following withdrawal of vecuronium; (ii) motor M potentials were of low amplitude, there was mild abnormal spontaneous activity on needle electromyography, and sensory conduction was relatively preserved; (iii) not all patients received glucocorticoids or were asthmatic; (iv) 2 patients given vecuronium had very high creatine kinase levels and developed acute renal failure associated with myoglobinuria; and (v) rises in motor M potentials accompanied clinical recovery. This complication of intensive care may be severe, but is reversible and possibly avoidable. Our findings implicate nondepolarizing muscle blocking agents in the development of the myopathy. Electrophysiological studies provide important prognostic guidance. © 1994 John Wiley & Sons, Inc.
Axonal neuropathy in eosinophilia–myalgia syndrome
Authors: Burns S. M. , Lange D. J. , Jaffe I. , Hays A. P.
Published: January 2005

Three patients with eosinophilia–myalgia syndrome linked to consumption of L‐tryptophan supplement developed a severe sensorimotor axonal neuropathy. All three had myalgia, elevated eosinophil count, and later developed fasciitis. Neuropathy was found at all stages of the illness and resulted in disability which was irreversible despite cessation of L‐tryptophan. Nerve conduction studies showed reduced motor and sensory evoked response amplitudes with select sparing of some nerves and the arms were more involved than the legs. Cerebrospinal fluid protein content was increased in one of two patients so tested. Creatine kinase was normal and muscle biopsy showed perimysial inflammation. Sural nerve biopsy in one case showed epineural perivascular inflammation. Our data showed that a severe sensorimotor axonal neuropathy occurs in eosinophilia–myalgia syndrome, suggestive of mononeuritis multiplex. © 1994 John Wiley & Sons, Inc.
Dystrophin and dystrophin‐related protein in the brains of normal and mdx mice
Authors: Uchino Makoto , Yoshioka Kowashi , Miike Teruhisa , Tokunaga Makoto , Uyama Eiichiro , Teramoto Hitoo , Naoe Hiroaki , Ando Masayuki
Published: January 2005

To clarify the localization and characterization of dystrophin and dystrophin‐related protein (DRP) in the brains of normal and mdx mice, we carried out immunostaining and immunoblotting studies using four region‐specific antidystrophin and anti‐DRP antibodies. With immunostaining, punctate immunoreactivity of dystrophin was seen along the cell bodies and dendrites of the cerebral cortical neurons in the normal mice. By contrast, dystrophin was not detected at all in the brains of mdx mice. Immunoreactivity of DRP was observed in the vascular walls, pia mater, and choroid plexus of both normal and mdx brains, but not in the neuronal cells. The possible compensatory increase of DRP as seen in the skeletal muscles of mdx mice was not noted in the brains. The immunoblot findings were very consistent with those of immunostain. Although further studies of brain‐type dystrophin are necessary, it seems unlikely that DRP participates in any physiological function of the neuronal cells. © 1994 John & Sons, Inc.
Limited benefit of electrophysiological studies during dorsal rhizotomy
Authors: Pollack Michael A.
Published: January 2005

Using a formula for standard deviation and several assumptions, the potential benefit of electrophysiological recording (ER) during dorsal rhizotomy for cerebral palsy is calculated and expressed in a ratio, the electrophysiological recording benefit ratio (ERBR). ERBR is approximately 1.1 in most of the examples, but other factors may reduce this ratio. Severing an additional rootlet appears to be a viable alternative to ER in most of the examples. Advantages of dorsal rhizotomy without ER include reduced expense and operative time. Prospective studies are recommended to evaluate further the benefit of ER during dorsal rhizotomy. If stimulation of dorsal rootlets is abandoned during dorsal rhizotomy, stimulation of whole dorsal and ventral roots may still be necessary to prevent inadvertent severing of motor fibers. © 1994 John & Sons, Inc.
Expression of myoglobin gene in skeletal muscle of patients with neuromuscular diseases
Authors: Kawai Hisaomi , Naruo Takako , Yoneda Kenji , Masuda Kenjiro , Mitsui Takao , Nishida Yoshihiko
Published: January 2005

Expression of the myoglobin (Mb) gene in skeletal muscle was studied in patients with Duchenne muscular dystrophy (DMD), polymyositis (PM), or amyotrophic lateral sclerosis (ALS) by measuring Mb concentration by radioimmunoassay and Mb messenger ribonucleic acid (RNA) (MbmRNA) levels by Northern blot analysis. Mb concentrations in the muscle cells (Mb/noncollagenous protein) were decreased in patients with DMD, PM, or ALS. However, while Mb concentrations per MbmRNA content (Mb/MbmRNA) were decreased in DMD and PM patients, these values were normal in ALS patients. These results suggest that Mb synthesis is increased in muscles of DMD and PM patients, but is not sufficient to compensate for the excessive loss of Mb from the affected muscles, and that the synthesis is decreased in the muscles of ALS patients. © 1994 John Wiley & Sons, Inc.
Compound sensory action potentials evoked by tactile and by electrical stimulation in normal median and sural nerves
Authors: Krarup Christian , Trojaborg W.
Published: January 2005

The compound sensory action potential evoked by electrical stimulation provides a measure of the number and physiological properties of myelinated fibers in the nerve but does not allow evaluation of the most distal part of the sensory nerve. This study compares the compound sensory action potential, evoked by electrical and tactile stimuli, and recorded through needle electrodes placed close to the median and sural nerves of 22 normal males aged 16–51 years. The tactile probe, with a slight preindentation, delivered an indentation of the skin of 200 μm at a rate of 400 μ/ms at the tip of digit III and the dorsolateral side of the foot. The responses were recorded from the median nerve at wrist and elbow and from the sural nerve at the lateral malleolus and midcalf. The amplitudes of the responses averaged 0.5 μV and 0.7 μV in the sural and the median nerves (P < 0.02), respectively, which was only 5–10% of the amplitude evoked by electrical stimulation. The mean maximal conduction velocity determined by tactile stimulation was 54 m/s in the sural nerve compared with 65 m/s in the median nerve and similar to that calculated after electrical stimulation. In the median nerve the sensory conduction velocity was 8% faster than the motor conduction velocity. These findings indicated that only a fraction of the fibers in the nerve were activated by the probe and that the response was conducted along large myelinated sensory fibers. The latency of the tactile response was longer than that of the electrically evoked response due to the receptor delay and conduction along thin distal fiber portions. The delay at the mechanoreceptors was about 1 ms in the sural and 0.65 ms in the median nerve (P < 0.01). © 1994 John Wiley & Sons, Inc.
Conduction velocity in motor, cutaneous afferent, and muscle afferent fibers within the same mixed nerve
Authors: Shefner Jeremy M. , Logician Eric L.
Published: January 2005

Mammalian axons subserving different functions have different conduction velocities (CV); motor fibers conduct more slowly than cutaneous fibers, which conduct slower than muscle afferents. However, human studies have yielded conflicting results. We studied isolated fiber populations in human sciatic nerve to examine further this question. Motor studies were performed in standard fashion, stimulating at gluteal fold (GF) and popliteal fossa (PF) and recording soleus. In addition, conduction velocity of a pure motor nerve volley was calculated for 3 subjects. Stimulating and recording electrodes were needles placed close to the nerve. Cutaneous afferents were studied by stimulating the sural nerve at the ankle and recording at PF and GF. Muscle afferent velocity was assessed by comparing soleus H reflex latency with stimulation at PF and GF. Results in 10 subjects showed muscle afferent CV of 57.6, cutaneous afferent CV of 55.1, motor CV of 52.4. and mixed nerve CV of 56.3 m/s. Although statistically significant, these differences are much smaller than in animal studies. These results have implications for understanding what fibers contribute to Spinal reflexes. © 1994 John Wiley & Sons, Inc.
Aberrant reinnervation following hypoglossal nerve damage
Authors: Wilson John R. , Sumner Austin J. , Eichelman Jutta
Published: January 2005

Hypoglossal nerve damage is a known complication of carotid endarterectomy, occurring in approximately 5% of endarterectomies. The vast majority of these patients recover without functional disability from this injury even if the tongue remains hemiplegic. We report 2 patients who suffered hypoglossal nerve section during neck surgery. Although they were initially mildly symptomatic, they developed increasingly severe dysarthria and dysphagia beginning 4 months after surgery. EMG revealed abnormal coactivation of the genioglossus and styloglossus muscles on the affected side, suggesting aberrant reinnervation. Aberrant reinnervation is a well‐known complication of facial nerve injury, but has not been previously recognized in hypoglossal nerve injury. Like the face, the tongue is composed of many muscles that must perform complex movements. Normally, injury to one hypoglossal nerve causes little or no disability, but when aberrant reinnervation occurs, the tongue no longer moves in a coordinated manner, and significant dysarthria ensues.
M/RMS: An EMG method for quantifying upper motoneuron and functional weakness
Authors: Haughton John F. , Little James W. , Powers Randall K. , Robinson Lawrence R. , Goldstein Barry
Published: January 2005

A new method for quantifying upper motoneuron (UMN) weakness using standard EMG equipment is presented and compared to the twitch occlusion method. Control subjects and patients with stroke, spinal cord injury (SCI), and peripheral nerve injury (PNI) were evaluated. Force, EMG, and twitch force from nerve electrical stimulation were recorded during isometric contractions of the biceps and triceps. Ratios of the elicited CMAP amplitude (M)/voluntary‐root‐mean‐square EMG activity (RMS) and of the voluntary contraction twitch force (T1)/ the resting twitch force (Tmax) were the two measures of UMN weakness studied. Both ratios are linearly correlated with force for controls, log M/RMS (r =s 0.96) and Ti/Tmax (r = 0.86). Log M/RMS ratio was abnormally high (> mean + 2 SD; i.e., >1.09) for weak muscles affected by stroke and incomplete SCI, but was normal in muscles weakened by PNI. An elevated M/RMS ratio, may aid in quantification of deficient supraspinal activation from UMN or functional weakness. © 1994 John Wiley & Sons, Inc.
Utilization of myoblasts from transgenic mice to evaluate the efficacy of myoblast transplantation
Authors: Kinoshita Ikuo , Huard Johnny , Tremblay Jacques P.
Published: January 2005

A possible treatment for Duchenne muscular dystrophy is the injection of normal myoblasts into dystrophic muscles to induce the formation of new, healthy, and dystrophin‐positive muscle fibers. To develop this therapy, it is important to identify the muscle fibers formed by the injected myoblasts in the host muscles. In this study, we used myoblasts from transgenic mice which have a gene expressing β‐galactosidase under the control of the promoter of quail fast skeletal muscle troponin I. This transgene is expressed in myotubes and muscle fibers, but not in myoblasts. Twenty‐eight days after myoblast transplantation in nude and in mdx mice, muscle fibers containing of β‐galactosidase were identified by x‐gal staining. In mdx mice, most of the β‐galactosidase‐positive muscle fibers resulting from the myoblast transplantation were also dystrophin positive. This technique could make it possible to follow the success of myoblast transplantation even in mice that are not depleted of dystrophin. © 1994 John Wiley & Sons, Inc.
Fatigue associated EMG behavior of the first dorsal interosseous and adductor pollicis muscles in different groups of subjects
Authors: Zijdewind Inge , Kernell Daniel
Published: January 2005

We have studied the fatigue‐associated behavior of surface EMG in two histochemically different muscles of the hand: first dorsal interosseous (FDI) and adductor pollicis (AP; relatively more type I fibers in AP than in FDI). During a fatigue test evoked by electrical stimulation of the ulnar nerve, the mean amplitudes of compound muscle action potentials (M‐waves) exhibited the same overall pattern for both muscles: a rapid phase of potentiation followed by a gradual decline. However, if the group of subjects was subdivided on the basis of hand length, significant differences emerged in the reactions of AP: in large hands, no fatigue‐associated M‐wave decline was seen, whereas in small hands a distinct decline was observed. A possible explanation for this phenomenon might be the presence of a greater amount of EMG contamination from other muscles in smaller hands. In the supposedly “cleaner” recordings from larger hands, significant differences between FDI and AP were observed with regard to their fatigue‐associated EMG reactions (M‐wave depression in FDI but not in AP). The direction of these differences was in accordance with expectations on the basis of known differences in histochemical fiber type composition. © 1994 John Wiley & Sons, Inc.