bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of thyroid hormones on the biochemical specialization of human muscle fibers
Authors: Salviati Giovanni , Zeviani Massimo , Betto Romeo , Nacamulli Davide , Busnardo Benedetto 
Published: January 2005

AbstractThe effects of thyrotoxicosis and of hypothyroidism on human muscle have been studied on single fiber preparations. In thyrotoxic muscle, the ratio between fibers showing the fast type of myofibrillar protein isoforms (fast fibers) and fibers showing the slow type (slow fibers) is increased, as is the percentage of fibers with incomplete segregation of fast and slow myosin (intermediate fibers). Furthermore, in fast fibers, the volume and, to a greater extent, the rate of Ca transport of sarcoplasmic reticulum (SR) are increased, without changes in the affinity for Ca2+ of the Ca‐pump or in its sensitivity to the cyclic adenosine monophosphate (cAMP) dependent protein kinase system. These effects are completely reversed by the removal of thyroid hormones, as demonstrated by hypothyroid muscles. It is suggested that in human muscle cells thyroid hormones are critical for the expression of fast genes and for SR Ca transport.
Transient conduction block following acute peripheral nerve ischemia
Authors: Parry Gareth J. , Cornblath David R. , Brown Mark J. 
Published: January 2005

AbstractWe studied the effects of transient focal ischemia on the electrophysiologic function of rat sciatic nerves. Focal and generalized impairment of impulse conduction, measured by falling evoked muscle and nerve compound action potential amplitudes, occurred within 10 minutes of femoral artery occlusion. Conduction failure reached a nadir at 45–60 minutes and then improved to normal within 24 hours. Fastest motor and mixed nerve conduction velocities were reduced less than 15% of baseline values during the period of acute conduction block. There were no detectable morphological abnormalities at the site of conduction failure. Transient ischemia produces reversible conduction block without evident structural changes. The fall in amplitude without significant conduction slowing implies that slower conducting myelinated fibers are relatively more sensitive to the effect of acute ischemia.
Somatosensory evoked potentials in motor neuron disease
Authors: Bosch E. Peter , Yamada Thoru , Kimura Jun 
Published: January 2005

AbstractWe studied median somatosensory evoked potentials (SEPs) in an unselected series of 30 patients with sporadic motor neuron disease (MND). SEPs were affected in 17 patients (57%), with a higher incidence of abnormality in amyotrophic lateral sclerosis and bulbar palsy than in progressive muscular atrophy. In a majority of patients, simultaneous bilateral stimulation of the median nerve revealed a delay or absence of scalp‐recorded central N32 and/or N60, leaving the earlier peaks intact. In the remaining cases, the N19 peak was asymmetrically prolonged. These findings suggest common involvement of somatosensory pathways in MND, either at cortical or subcortical levels, and correlate with neuropathologic reports of neuronal degeneration beyond the primary motor system.
Type 2 fiber predominance in muscle cramp and exertional myalgia
Authors: Telerman‐Toppet Nicole , Bacq Michèle , Khoubesserian Patrick , Coërs Christian 
Published: January 2005

AbstractIn patients complaining of muscle cramps and exertional myalgia, we found a significant decrease of type 1 muscle fiber proportion in comparison with a control group. The possible mechanism of this change is discussed.
Structure of motor nerve terminals in chickens with hereditary muscular dystrophy
Authors: Gunther Joan S. , Letinsky Michael S. 
Published: January 2005

AbstractThe structure and size of 1‐week to 1‐year‐old normal (line 412) and dystrophic (line 413) chicken motor nerve terminals were studied using combined pre‐ and postsynaptic histologic endplate staining. The main result is that adult dystrophic terminals have abnormal structure and are significantly smaller than normal. These differences occurred progressively during development. At 1 week ex ovo, dystrophic motor nerve terminals were similar to normals in size and appearance. By 8 weeks, differences between normal and dystrophic terminal size and structural organization began to emerge. Qualitatively, beginning at 8 weeks and becoming more frequent by 1 year of age (the endpoint of this study), dystrophic motor endplates differed from normal in having: (1) generally smaller synaptic boutons, often separated by extremely thin branching interconnectives; (2) increasing incidence of multiple innervation; and (3) frequent occurrences of apparent partial or total denervation, terminal sprouting, and reinnervation.
Decreased parvalbumin contents in skeletal muscles of C57BL/6J(dy2J/dy2J) dystrophic mice
Authors: Klug Gary , Reichmann Heinz , Pette Dirk 
Published: January 2005

AbstractParvalbumin content is decreased by 40% in hindlimb muscles of adult (3.5 months) dystrophic mice when compared to normal mice of the same age. The concentration of parvalbumin in the dystrophic muscles resembles that of immature muscles of 4‐week‐old normal mice. The reduction may contribute to an elevation of sarcoplasmic free CA2+, which could stimulate various Ca2+‐dependent processes related to the disease.
Pulmonary function and electromyographic study of respiratory muscles in myotonic dystrophy
Authors: Jammes Y. , Pouget J. , Grimaud C. , Serratrice G. 
Published: January 2005

AbstractTen adult myotonic dystrophy patients underwent measurements of lung function, maximal dynamic and static ventilatory efforts, and respiratory muscle electromyography (EMG). EMG studies were performed during spontaneous breathing or when subjects breathed through high inspiratory or expiratory resistive loads. Present results show that (1) a moderate restriction of lung volumes with hypoxemia plus normocapnia is often observed; (2) patients sustain dynamic ventilatory efforts more easily than static work; and (3) abnormalities in respiratory muscle EMG exist with spontaneous expiratory and inspiratory intercostal activities during quiet breathing and changes in muscular response to resistive loads. Inspiratory loading evokes contraction of expiratory muscles, with a marked decrease in inspiratory activities. Expiratory resistive loads prolong the diaphragmatic contraction throughout the expiratory time, and in some patients, relaxation of the diaphragm does not occur during the loaded run. These EMG data suggest that the reciprocal inhibition among respiratory neurons is enhanced in myotonic dystrophy and that myotonia also occurs in the diaphragm when loads oppose its relaxation.
Muscle energy metabolism in duchenne dystrophy studied by 31P‐NMR: Controlled trials show no effect of allopurinol or ribose
Authors: Griffiths Richard D. , Cady Ernest B. , Edwards Richard H. T. , Wilkie Douglas R. 
Published: January 2005

Abstract31P nuclear magnetic resonance (NMR) was used to investigate the resting energy metabolism of the calf muscle in boys with Duchenne's muscular dystrophy. Reductions in the phosphocreatine/adenosine triphosphate (PCr/ATP) and the PCr/Pi ratios were found, but ATP as a fraction of the total mobile phosphorus signal was not reduced, and intracellular pH was normal in the Duchenne muscle. Attempts at quantitation of the NMR signal suggested that the reduced total phosphorus signal seen in the Duchenne muscle was a result of muscle fiber loss only and that the muscle fiber ATP concentration was probably normal in the diseased tissue. An exercise study in one 7‐year‐old boy with Duchenne's dystrophy demonstrated that the muscle had a normal ability to break down and resynthesize phosphocreatine. Presented here are the first reported trials of the effects of two putative therapeutic agents on energy metabolism determined by NMR in Duchenne's muscular dystrophy.
Distribution of different fiber types in human skeletal muscles: Why is there a difference within a fascicle?
Authors: Sjöström Michael , Downham David Y. , Lexell Jan 
Published: January 2005

AbstractThe proportions of different fiber types (type 1 and type 2) on the borders of fascicles are shown to differ from the proportions internally. This finding is based on the analysis of a total of 245 fascicles from whole cross‐sections of the vastus lateralis muscle from 13 men, aged from 26–80 years. Generally, the difference is more marked in the young than in the old. It is argued that the causes of this difference are likely to be local factors in the muscle.
Fetal myosin immunoreactivity in human dystrophic muscle
Authors: Schiaffino Stefano , Gorza Luisa , Dones Ivano , Cornelio Ferdinando , Sartore Saverio 
Published: January 2005

AbstractWe report immunofluorescence observations on normal and dystrophic human muscle using an antibody (anti‐bF) raised against bovine fetal myosin and specific for fetal myosin heavy chains. In rat skeletal muscle, anti‐bF was previously found to react selectively with myosin isoforms expressed during fetal and early postnatal development and in regenerating muscles.11 Anti‐bF stained most fibers in human fetal and neonatal muscle, whereas only nuclear chain fibers of muscle spindles were labeled in normal adult muscle. In muscle biopsies from patients with Duchenne's muscular dystrophy, numerous extrafusal fibers were stained: some were small regenerating fibers, others were larger fibers presumably resulting from previous regenerative events. Fetal myosin immunoreactivity in Duchenne's dystrophy appears to reflect the reexpression of fetal‐specific myosin isoforms and provides a new valuable tool for identifying regenerating fibers and following their destiny in dystrophic muscle.
Motor neuropathy associated with a facilitating myasthenic syndrome
Authors: Subramony S. H. , Mitsumoto H. , Mishra S. K. 
Published: January 2005

AbstractWe report a patient with progressive muscle weakness, areflexia, and no sensory loss. Electromyography revealed normal sensory nerve conductions, mild slowing of motor nerve conduction velocities, low amplitude compound muscle action potentials, a neuromuscular transmission defect characterized by prominent facilitation, and diffuse fibrillation potentials. Muscle biopsies showed acute denervation atrophy, and at autopsy, there was anterior horn cell loss and gliosis in the spinal cord. The findings suggest the coexistence of a motor neuropathy and a facilitating myasthenic syndrome.
Isolation and characterization of sarcoplasmic reticulum from normal and dystrophic chicken
Authors: Kawamoto Richard M. , Baskin Ronald J. 
Published: January 2005

AbstractPurified sarcoplasmic reticulum vesicles from normal and dystrophic chicken skeletal muscle have been isolated by a procedure employing pressure disruption of a microsomal suspension. The dystrophic sarcoplasmic reticulum (SR) exhibited reduced Ca+ + transport and phosphoenzyme formation, but the Ca + + ‐ATPase activity was normal. Normal and dystrophic SR showed similar lipid profiles, except for a significant increase in free fatty acids in the dystrophic SR. Investigations involving the interaction of oleic acid with normal SR showed fatty acids can induce conditions similar to those found in dystrophic SR.
Treatment of hypersomnolence in myotonic dystrophy with a CNS stimulant
Authors: van De Meché Frans G. A. , Boogaard Jan M. , van Den Berg Bart 
Published: January 2005

AbstractA 42‐year‐old man with myotonic dystrophy developed severe hypersomnolence during the year prior to admission for acute respiratory insufficiency. However, his hypersomnolence could be attributed to a central dysfunction, and during a follow‐up period of 3 years, was successfully treated with methylphenidate.
A trial of flunarizine in the treatment of duchenne muscular dystrophy
Authors: Dick David J. , Gardner‐medwin David , Gates Peter G. , Gibson Mary , Simpson Judy M. , Walls Timothy J. 
Published: January 2005

AbstractTwenty‐seven boys with Duchenne muscular dystrophy (DMD) entered a double‐blind controlled trial of treatment with the calcium antagonist flunarizine. They were matched for age and disability. At monthly intervals, muscle power, functional ability, locomotor score, contractures, and forced vital capacity were measured by a team not involved in clinical care. Over a period of 1 year, flunarizine in a dose of up to 0.25 mg/kg/day had no effect on the clinical course of the disease.
The influence of skeletal muscle reinnervation on experimentally induced myotonia
Authors: Al‐sulaiman Abdulsalam , Al‐Rajeh Saad , Iyer Vasudeva 
Published: January 2005

AbstractEarlier studies have shown that prior denervation of muscle prevents myotonia induced by 2,4‐dichlorophenoxy acetic acid (2,4‐D) both in vivo and in vitro. This work studied the effect of reinnervation on 2,4‐D myotonia. Twenty Sprague‐Dawley rats were injected with 2,4‐D at specific intervals following unilateral sciatic nerve crushing; the gastrocnemius muscle on both sides was studied electromyographically to assess myotonia and to document denervation and reinnervation. All the rats gradually became amyotonic following denervation; myotonia reappeared during reinnervation. Myotonic discharges were no longer detectable 1 week after nerve crushing, but returned completely within 3 weeks. Blocking axoplasmic transport with colchicine had essentially the same effect on myotonia. A reciprocal temporal relationship was noted between the occurrence of fibrillations and myotonic discharges. These findings substantiate the view that innervation is essential to maintain the muscle membrane in a state that will support myotonic discharges.
The muscle slice—A new preparation for the characterization of β‐adrenergic binding in fast‐ and slow‐twitch skeletal muscle
Authors: Watson ‐Wright Wendy M. , Wilkinson Michael 
Published: January 2005

AbstractA new procedure is presented that characterizes the specific binding of the β‐adrenergic antagonist, [3H]CGP‐12177, to thick (1 mm) slices from fast‐twitch [extensor digitorum longus (EDL)] and slow‐twitch (soleus) mouse skeletal muscle. Binding is reversible, saturable, stereospecific, of high affinity, and subject to agonist‐induced desensitization, indicating that it is to β‐adrenoreceptors and not to other sites. In both muscles, the majority of specific binding is to the β2‐receptor subtype. Bmax is approximately twice as high in the soleus (5.64 ± 0.52 fmol/mg wet weight) as in the EDL (2.66 ± 0.29 fmol/mg wet weight) (P < 0.05), whereas affinity is higher in the fast‐twitch (Kd = 0.30 ± 0.08 nM) than the slow‐twitch muscle (Kd = 0.45 ± 0.08 nM). The minimal tissue disruption associated with this procedure, as well as its speed, simplicity and relatively low cost, suggest that the slice preparation may prove to be invaluable for the future study of β‐adrenergic receptor binding and associated responses in skeletal muscle.
Induction of spheroid cytoplasmic bodies in a rat muscle by local tetanus
Authors: Chou Samuel M. , Mizuno Yoshihiko 
Published: January 2005

AbstractThe term “cytoplasmic body” or “spheroid body” myopathy refers to a heterogeneous group of familial or sporadic diseases characterized primarily by the presence of abundant spheroid or cytoplasmic bodies in the muscles. The morphogenesis of these inclusions remains unclear. This article describes the induction and evolution of spheroid cytoplasmic bodies (SCBs) in the rat plantaris muscle (PL) with local tetanus, which was induced in rats by the injection of a minute amount of tetanus toxin. In contrast to the tetanized soleus muscle (SOL), which developed core fibers (central cores, minicore, target fiber, targetoid fiber, and rods), the tetanized PL produced numerous SCBs with a predictable time course. They were induced in both type 1 and 2 fibers of PL, which is composed predominantly (95%) of type 2 fibers, in contrast to SOL (85% type 1 fibers). Factors inducing SCBs may include immobilization, shortening, intact innervation, and disuse atrophy.
Automatic analysis of the electromyographic interference pattern. Part II: Findings in control subjects and in some neuromuscular diseases
Authors: Nandedkar Sanjeev D. , Sanders Donald B. , Stålberg Erik V. 
Published: January 2005

AbstractThe electromyographic (EMG) interference pattern (IP) was measured in the biceps muscle of 16 normal male and 17 normal female subjects. The activity, upper centile amplitude (UCA), and the number of small segments (NSS) (defined in a companion paper) were measured from 500‐msec epochs of the IP. The normal values of these features were defined separately for men and women by plotting the UCA and NSS values against activity for each epoch and defining an area on these plots, called a “cloud,” that contained more than 90% of the datum points from each study. The mean deviation of the individual datum points from the overall mean values was also calculated for each study. A study in one muscle is considered to be normal if more than 90% of the datum points from that muscle are within the normal clouds and the deviation values are within their normal range. In patients with neuropathy, the characteristic pattern was increased UCA with normal or decreased NSS. In patients with myopathy, NSS was increased and the UCA was normal or decreased. In all studies, the interpretations of the IP from the plots agreed with qualitative assessments of the IP made independently by an electromyographer. The use of these features to understand and quantitate the changes in the motor units produced by disease is demonstrated by serial studies performed in a patient with motor neuron disease.
Disorders of neuromuscular transmission in infants and children
Authors: Cornblath David R. 
Published: January 2005

AbstractDisorders of neuromuscular transmission in infants and children can be divided into two groups. The first group includes conditions similar to those seen in adults: autoimmune myasthenia gravis, Lambert‐Eaton myasthenic syndrome, and botulism. The second includes several disorders that are unique to this age group, such as the congenital myasthenias and infantile botulism. This review discusses the diseases of neuromuscular transmission found in the pediatric population, with emphasis on electrodiagnosis. The distinctive clinical and electrophysiologic features allow the clinician to identify these illnesses correctly, so that appropriate treatment can be instituted or further specialized investigation can be undertaken.
The exercise test in periodic paralysis
Authors: McManis Philip G. , Lambert Edward H. , Daube Jasper R. 
Published: January 2005

AbstractOf 21 patients with clinically definite hypokalemic, hyperkalemic, or normokalemic periodic paralysis, 15 (71%) had a greater than normal increase in compound muscle action potential amplitude during 2–5 minutes of intermittent strong voluntary contraction of the muscle. This increase was followed by a progressive decline in amplitude, which was greater than in a control population and which was most rapid during the first 20 minutes after exercise. The amplitude often decreased to a level below the preexercise level. A similar response was seen in six of nine patients with periodic paralysis secondary to disorders such as thyrotoxicosis. This test may have value in the identification of patients with periodic paralysis.
AAEE Case report #12: Common peroneal mononeuropathy at the fibular head
Authors: Wilbourn Asa J. 
Published: January 2005

AbstractCommon peroneal monoeuropathies, usually located at the fibular head, are one of the many causes of foot‐drop, a condition often evaluated in the electromyography laboratory. If appropriate nerve conduction studies are performed and particular muscles studied on needle myography, a satisfactory diagnosis can almost always be provided for what may be a perplexing problem clinically. With all peroneal mononeuropathies, the compound muscle action potential amplitude of the peroneal motor tibialis anterior nerve conduction studies, stimulating distal to the fibular head, is a semiquantitative measure of the number of viable fibers supplying the tibialis anterior and allows for accurate prognostication regarding the foot‐drop.
Acute arsenic intoxication presenting as guillainbarréa‐like syndrome
Authors: Donofrio Peter D. , Wilbourn Asa J. , Albers James W. , Do Lisa Rogers, , Salanga Virgilio , Greenberg Harry S. 
Published: January 2005

AbstractArsenic‐induced polyneuropathy is traditionally classified as an axonal‐loss type, electrodiagnostically resulting in low amplitude or absent sensory and motor responses, relatively preserved proximal and distal motor conduction rates, and distal denervation. We report four patients with a subacute onset progressive polyradiculoneuropathy following high‐dose arsenic poisoning. In three patients, early electrodiagnostic testing demonstrated findings suggestive of an acquired segmental demyelinating polyradiculoneuropathy. Serial testing confirmed evolution into features of a distal dying‐back neuropathy. We hypothesize that arsenic toxicity and the resultant biochemical derangement of the peripheral nerve cell leads to subtle changes in axonal function that produce, initially, segmental demyelination and eventually distal axonal degeneration. Acute arsenic toxicity must be suspected in patients with clinical and electrodiagnostic features supporting Guillain‐Barré syndrome.
Electrophysiologic studies of critically ill patients
Authors: Bolton Charles F. 
Published: January 2005

AbstractSepsis and critical illness occur as complications of illness, injury, or surgery in approximately 5% of patients in our critical care unit. Clinical evaluation of the nervous system is difficult in this clinical setting, and electrophysiologic studies are therefore quite valuable. Electroencephalography detects encephalopathy and electromyography (EMG) and nerve conduction studies detect neuromuscular disorders at early stages of their development. Thus, septic encephalopathy occurs in almost all patients and critically ill polyneuropathy in at least 50% of such patients. The polyneuropathy is a predominantly distal axonal degeneration of motor and sensory fibers. A catabolic myopathy is also present, but is difficult to detect electrophysiologically. No defect in neuromuscular transmission has so far been demonstrated. Both the encephalopathy and polyneuropathy may be quite severe, but with vigorous management of the sepsis and critical illness complete recovery may occur in the 40% of patients who survive.
Superoxide dismutases, Glutathione peroxidase, And catalase in neuromuscular Disease
Authors: Burr Ian M. , Asayama Kohtaro , Fenichel Gerald M. 
Published: January 2005

AbstractStudies in experimental muscular dystrophy indicate a possible role for anomalous redox metabolism in the genesis of these disorders, prompting a retrospective review of changes in redox‐active enzymes in Duchenne muscular dystrophy (DMD). Both manganous and copper‐zinc superoxide dismutase (Mn and CuZn SOD) content and glutathione peroxidase and catalase activities were measured in muscle biopsy specimens taken from normal individuals and from patients with Duchenne muscular dystrophy and other neuromuscular diseases. Muscle from patients with Duchenne dystrophy differed from the norm in that both Mn SOD and CuZn SOD were decreased and glutathione peroxidase was increased. This profile differed from that in anterior horn cell diseases in that CuZn SOD was not decreased in these disorders and from polymyositis, where CuZn SOD was decreased without an increase in glutathione peroxidase. Thus, there appears to be disease‐specific changes in these enzymes in DMD. These data support the concept that changes in redox‐active enzymes may be associated with the genesis of DMD.