bluuebunny/crossref_metadata_2025_split huggingface dataset:
Schwann cell changes and demyelination in chronic galactose neuropathy
Authors: Powell H. C. , Myers R. R. 
Published: January 2005

AbstractDystrophic changes of Schwann cells and demyelination occurred in rats with chronic nerve edema induced by feeding a galactose‐rich diet for two years. The mechanism for edema is the sorbitol pathway which generates osmotically active polyols from galactose or glucose. The blood‐nerve barrier impedes diffusion of macromolecules from peripheral nerves, and endoneurial fluid pressure (EFP) becomes elevated. After 24–26 months of feeding with 40% galactose diet, myelinated nerve fibers showed segmental demyelination with bubbly disintegration of myelin sheaths, axonal degeneration, and remyelination. These pathologic changes were significantly more common than similar abnormalities in age‐matched controls. Massive glycogen accumulation in Schwann cells, a unique morphologic finding, appeared only in experimental rats. Since edema and increased EFP are the earliest pathologic changes and are present for months before demonstrable nerve fiber injury, we suggest that they are responsible for the changes of myelinated fibers in chronic galactose neuropathy.
Large delayed plasma creatine kinase changes after stepping exercise
Authors: Newham D. J. , Jones D. A. , Edwards R. H. T. 
Published: January 2005

AbstractMuscle changes have been examined in 16 normal subjects (eight female) after both a 20‐minute and a prolonged step test. Stepping differs from most exercise tests in that it involves eccentric contractions (negative work) in which the active muscle is lengthened. Plasma creatine kinase (CK), muscle force, contractile properties, and tenderness in the quadriceps were measured for up to 9 days after the exercise. Muscle tenderness was experienced only in the muscles that had performed eccentric contractions (i.e., stepped down). All subjects showed some early rise in CK (<400 IU/liter) but eight (both male and female) showed a much greater response (up to 34,500 IU/liter) which took a long time to reach peak levels (4–5 days after stepping). It is suggested that eccentric contractions involved in this form of exercise result in some particular form of muscle damage which, in susceptible subjects, may initiate changes giving rise to a large delayed release of muscle enzymes.
Calmodulin content and Ca‐activated protease activity in dystrophic hamster muscles
Authors: Klamut Henry J. , Lin Chao Hsiung , Strickland Kenneth P. 
Published: January 2005

AbstractAs part of a study on the implication of elevated Ca2+ levels in the myofibrillar degeneration seen in dystrophic muscle, the content of calmodulin and the activity of Ca2+ ‐activated neutral protease (CANP) have been measured in normal and dystrophic (UM‐X7.1) hamsters. Calmodulin levels, expressed as micrograms ± SEM per gram wet weight were highest in brain (385 ± 24.7), followed by tongue (93.88 ± 3.93), heart (42.13 ± 2.93), and skeletal muscle (31.69 ± 1.42). No significant increases in calmodulin were observed in the dystrophic tissues thus suggesting that the Ca2+ accumulations observed in dystrophic muscles are unrelated to changes in calmodulin levels. Because of the complexity of regulation of CANP, a time‐dependent study was done using extracts of skeletal, heart, and tongue muscles. Marginal increases in dystrophic CANP were seen in skeletal muscle at all times studied and in the heart and tongue at initial time points only. The data are discussed in terms of rising levels of Ca2+ in muscles of the UM‐X7.1 hamster being sufficient to increase CANP activity (without increasing content) to where it causes Z‐line dissolution.
Effects of crush injury on the abnormalities in the spinal roots and peripheral nerves of dystrophic mice
Authors: Bray Garth M. , David Samuel , Carlstedt Thomas , Aguayo Albert J. 
Published: January 2005

AbstractLumbosacral spinal roots and peroneal nerves in dystrophic and control mice were crushed and allowed to regenerate. Six weeks after crush injury, the dystrophic roots no longer showed the typical groups of unensheathed axons that characterize the uncrushed roots. Thus, the location of this ensheathment defect in the spinal roots cannot be the exclusive mechanism responsible for its development. Crush injury and regeneration also tended to correct a second abnormality in the peripheral nervous system of dystrophic mice: the discontinuities in the Schwann cell basal laminas. Because the regenerated nerves contained increased amounts of collagen, the results of this study support the evidence from tissue culture experiments that the extracellular matrix may be involved in the pathogenesis of these disorders. However, the outcome of the present in vivo experiments indicates that genetically normal fibroblasts are not required for this change to occur.
Muscle pyruvate oxidation following denervation and reinnervation
Authors: Evans Owen B. 
Published: January 2005

AbstractMuscle pyruvate metabolism was studied in rats following sciatic nerve crush. Control studies showed high pyruvate dehydrogenase and lipoamide dehydrogenase enzyme activity in muscle with type 1 fiber predominance (soleus) and low activities in muscle with type 2 fiber predominance (extensor digitorum longus), whereas lactate dehydrogenase was much higher in the latter. Following denervation, both muscles showed a significant reduction in pyruvate dehydrogenase enzyme activity. During reinnervation, muscle with type 2 predominance developed significantly elevated pyruvate oxidation enzyme activities.
Thickening of the human dorsal root ganglion perineurial cell basement membrane in diabetes mellitus
Authors: Johnson Peter C. 
Published: January 2005

AbstractLumbar dorsal root ganglia were sampled at autopsy from 27 diabetics and 22 nondiabetics. Using quantitative ultrastructural morphometry, the perineurial cell basement membrane thickness was estimated for each case, and a highly significant difference was found between the patient means for each group (nondiabetics 114 ± 18 nm vs. diabetics 203 ± 64 nm, P < 0.001). These results indicate that perineurial cell basement membrane thickening probably is present diffusely throughout the diabetic peripheral nervous system because it has been reported in the sural nerves and dermal nerves. The increased permeability of the blood‐nerve barrier of the dorsal root ganglia is apparently not a factor in the development of this basement membrane hypertrophy.
The neurotoxins 2,5‐hexanedione and acrylamide promote aggregation of intermediate filaments in cultured fibroblasts
Authors: Durham Heather D. , Pena Sergio D. J. , Carpenter Stirling 
Published: January 2005

AbstractAxonal swellings associated with large aggregates of neurofilaments are characteristic of neuropathies caused by chemical neurotoxins (nhexane, methyl n‐butyl ketone, and acrylamide) or giant axonal neuropathy (GAN—an autosomal recessive genetic disease). In GAN, filamentous aggregates have been shown also to occur in other cell types including cultured skin fibroblasts. Therefore, we studied the effects of 2,5‐hexanedione (the neurotoxic metabolite of n‐hexane and methyl n‐butyl ketone) and acrylamide on normal human skin fibroblasts in tissue culture. We show that both neurotoxins induce aggregation of intermediate, filaments of the vimentin type in the cultured fibroblasts without disrupting microtubules.
Acetylcholinesterase molecular forms in C57BL/6J dystrophic mice
Authors: Lindenbaum Michael H. , Livett Bruce G. 
Published: January 2005

AbstractAcetylcholinesterase (AChE) was extracted from normal and dystrophic C57BL/6J mouse hindlimb muscles and its molecular forms fractionated by sucrose density gradient ultracentrifugation. In the soleus muscles from 6‐ to 7‐week‐old mice an increase in the 3 Svedberg unit (S) and a decrease in the 16S AChE molecular forms was observed in dystrophic animals compared to controls. At 12–13 weeks of age, no major significant differences in the relative proportions of AChE molecular forms were noted. In the extensor digiorum longus (EDL) muscles of 6‐ to 7‐week‐old dystrophic mice a significant decrease in the proportion of the 10S AChE molecular form and an increase in the 3S and 5S forms was observed. At 12–13 weeks, the dystrophic EDL muscles again displayed a decrease in the 10S form; however, the increase in the 3S and 5S AChE forms, while still apparent, was not significant. These results provide evidence for a biochemical abnormality in the distribution of specific AChE molecular forms, and a differential expression of this abnormality in the soleus and EDL muscles.
AAEE case report #8: The tarsal tunnel syndrome
Authors: Delisa Joel A. , Saeed Mohammad A. 
Published: January 2005

AbstractTarsal tunnel syndrome is relatively rare and the diagnosis may be difficult even though the etiologies for the syndrome are multiple. The symptoms are often vague but are usually burning pain and paresthesias in the toes and soles of the feet with nocturnal exacerbations. The physical examination may elicit a sensory deficit over the cutaneous distribution of the median and/or lateral plantar nerve. There may also be tenderness over the flexor retinaculum. Electrodiagnosis, especially with the addition of the orthodromic compound nerve action potential latency technique, is essential to confirm the diagnosis. The findings may be confined to the distribution of either the medial or lateral plantar nerves and, thus, both distal latencies must be determined. Surgical decompression of the tarsal tunnel has usually proven to be helpful in those patients who do not respond to conservative treatment.
Neuromuscular disorders in a new toxic syndrome: Electrophysiological study—a preliminary report
Authors: Martínez A. Cruz , Conde M. C. Pérez , Ferrer M. T. , Cantón R. , Téllez I. 
Published: January 2005

AbstractThe electrophysiological features in 145 patients with a new toxic syndrome related to ingestion of adulterated oil are described. Myalgia, joint limitation, weight loss, cramps, progressive weakness and wasting, sensory disturbances that can be asymmetrical or patchy, and scleroderma‐like changes were the main clinical features. The electrophysiological findings suggest that the neuromuscular impairment in the new toxic syndrome is a slowly progressive mixed axonal neuropathy, which starts asymmetrically in some patients, with involvement of proximal and distal muscles as well as paraspinal and respiratory muscles. Muscle and nerve biopsies confirm the neuropathy, and show severe perineuritis and perineurial and perimysial fibrosis. The single fiber electromyography (SFEMG) study showed increased motor unit fiber density directly related to the time after onset of the illness. Unstable complex potentials were found after 6 months of evolution, which suggests that can effective collateral reinnervation was delayed following a long period of progressive denervation.
Reduced acetylcholine sensitivity in dystrophic mouse myotubes in vitro
Authors: Cossu Giulio , Eusebi Fabrizio , Molinaro Mario 
Published: January 2005

AbstractAcetylcholine (ACh) sensitivity in cultured myotubes from normal or dystrophic mice was investigated using conventional techniques. Dystrophic multinucleate myotubes were found to be less responsive to the ACh with respect to the control preparation. Such a reduced sensitivity to ACh in dystrophic myotubes was accompanied by a reduced binding to125I‐alpha‐bungarotoxin. The possible biological significance of these results on the muscle disease is discussed.
Focal inflammatory myopathy
Authors: Lederman Richard J. , Salanga Virgilio D. , Wilbourn Asa J. , Hanson Maurice R. , Dudley Alden W. 
Published: January 2005

AbstractWe report three patients with inflammatory myopathy who presented clinically with weakness and wasting of only one limb. The myopathy progressed over 6 months and 5 years, respectively, in two patients and was stable after 8 years in the third patient. One patient had a skin rash. Serum CK was elevated in the two patients with progressive disease. Electromyography showed brief duration, small amplitude motor unit potentials and fibrillations in the affected limbs. Muscle biopsy revealed variable fiber size, degenerating and regenerating fibers, and inflammatory foci. Vasculitis was seen in the patient with skin lesions and marked fibroblastic proliferation in the patient with the most chronic course. Immunosuppressive therapy has arrested the progression in the two patients treated; both have regained strength.
Regulation of sarcomere number in skeletal muscle: A comparison of hypotheses
Authors: Herring Susan W. , Grimm Arthur F. , Grimm Betsy R. 
Published: January 2005

AbstractSarcomere lengths from 16 locations in the muscles of mastication were measured from pigs fixed in maximum excursion (wide jaw opening) and in postural position (near occlusion). These data, plus published data on sarcomere lengths in rabbit jaw muscles, were used to evaluate conflicting hypotheses about the factors which regulate serial sarcomere number in striated muscles. According to the most successful hypothesis, sarcomere number is adjusted so as to achieve an optimum sarcomere length when the muscle is experiencing a high level of tension. Most often, this occurs at jaw positions where the muscle is electrically active.
The effects of chronic muscular activity on age‐related changes in single fiber electromyography
Authors: Shields Robert W. , Robbins Norman , Verrilli Albert A. 
Published: January 2005

AbstractSingle fiber electromyography (SFEMG) of the extensor digitorum communis (EDC) muscle and nerve conduction studies were performed on healthy, active elderly men (66–77 years old) to assess age‐related changes in neuromuscular physiology and the effect of long‐term increased muscular activity on these changes. The following two groups were studied: a control group and a group composed of men with occupationally greater usage of hand extensors. Fiber density and mean jitter were essentially the same in both groups; however, in the hand‐user group there was greater variability in mean jitter and a significant increase in the prevalence of potential pairs with increased jitter or blocking. In both groups, slower nerve conduction velocities and lower amplitudes of sensory and motor evoked potentials tended to correlate with increased jitter and fiber density. These electrophysiological changes in healthy aged men are consistent with an extremely mild process of nerve terminal denervation and reinnervation. Although long‐term increased synaptic activity did not greatly alter the rate or extent of this process, it did produce a higher incidence of abnormal potential pairs and greater variability in mean jitter.
Abnormal use of remaining motor units during locomotion in peroneal palsy
Authors: Grimby Lennart , Holm Kerstin , Sjöuström Lars 
Published: January 2005

AbstractThe firing properties of single anterior tibial motor units were studied (during walking) with electromyogram (EMG) techniques in five normal subjects and in 10 patients who had footdrop due to an acute lesion of the common peroneal nerve. In the normal subjects, high threshold units did not fire in the ordinary step cycle and low threshold units fired at 10–25 Hz. In half of the paralyzed subjects, all motor units fired at 40–50 Hz for more than 200 msec in each step cycle, which could be sufficient for maximal force. In the other half of the paralyzed subjects, high threshold units were not reruited in each step cycle and low threshold units fired at 15–35 Hz, indicating that there were force reserves which were not used to prevent footdrop in each stride.
Rabbit sural nerve responses to chronic treatment with thalidomide and supidimide
Authors: Schwab Bradley W. , Arezzo Joseph C. , Paldino Albert M. , Flohe Leopold , Matthiessen Theo , Spencer Peter S. 
Published: January 2005

AbstractChronic treatment of rabbits with thalidomide (3‐(N‐phthalimido) glutarimide) produced progressive decrements in sural nerve conduction velocity (NCV) that were unassociated with qualitative or quantitative morphological changes of nervous tissue. Three groups of eight rabbits received 100 mg/kg/day thalidomide (group I), 200 mg/kg/day supidimide (a related drug) (group II), or a carboxymethylcellulose vehicle (group III) 5 days/week for 40 weeks. At 6 months of treatment, a noninvasive determination of the mean maximum sural NCV for group I was significantly reduced relative to the conduction velocities of groups II and III. Direct measurement of conduction velocity when treatment was terminated confirmed these findings and demonstrated similar conduction deficits in proximal and distal portions of the sural nerve in group I animals. At 6 months, rabbits in group II showed a significant reduction in mean conduction velocity, and, at the termination of treatment, they displayed mean values similar to that of group III and significantly greater than that of group I. Morphological findings were unremarkable in 20 regions of the central nervous system (CNS) and the peripheral nervous system (PNS) known to display changes early in toxic neuropathies. Morphometric estimation of unmyelinated and myelinated fibers in the sural nerve at the heel revealed no between‐group differences in axon diameter, fiber diameter, g‐ratio (the ratio of inside/outside diameters), or internodal length. In conclusion, chronic treatment with thalidomide produces selected decrements in sural nerve function that have an unknown relationship to the poorly reversible sensory neuropathy reported in humans receiving this drug.
Excretion of total and muscular Nτ‐methylhistidine and creatinine in muscle diseases
Authors: Röuthig H.‐Jürgen , Bernhardt Wolfgang , Afting Ernst‐Günther 
Published: January 2005

AbstractThe daily urinary excretions of Nτ‐methylhistidine and creatinine from 52 adult patients were measured under standardized conditions. The ratio of Nτ‐methylhistidine to creatinine excretion was calculated on the basis of the total and muscle‐specific excretion rates and correlated to the clinical status of the patients. In patients with muscular diseases and in those with diseases of the central nervous system, the total daily excretion of both metabolites was about 30% lower than in controls. The muscle‐specific ratio in patients with diseases of the central nervous system and patients with muscular diseases was not different from that observed in controls. Only in patients with neurogenic atrophies was the ratio elevated, so that it was more than twice the control value. The ratio of excreted Nτ‐methylhistidine/creatinine is only valid as an indicator of myofibrillar protein breakdown after correction for the contribution of nonskeletal muscle tissues to the urinary excretion.
Regenerative capability of skeletal muscle in chicken muscular dystrophy
Authors: Nonaka Ikuya , Fujita Takehisa , Sugita Hideo 
Published: January 2005

AbstractTo examine the morphological sequence of regenerating fibers after myonecrosis in dystrophic muscles, 0.5 ml of 0.5% bupivacaine hydrochloride (BPVC) (Marcaine) solution, a local anesthetic with a cytotoxic effect on the muscle fibers, was injected directly into the dystrophic (line 413) and nondystrophic (line 412) posterior latissimus dorsi (PLD) muscles of young and adult chickens. Although the dystrophic muscles after BPVC injection showed a rapid recovery with a similar tempo to that of nondystrophic ones, they showed different morphological behavior in the early phase of regeneration, including marked variability in the size of fibers and in the intracytoplasmic enzyme activities of nicotinamide adenine dinucleotide, reduced‐tetrazolium reductase (NADHTR), acetylcholinesterase (AChE), and nonspecific esterase (NSE).
Contractile and fatigue properties of thyrotoxic rat skeletal muscle
Authors: Fitts Robert H. , Brimmer Cheryl J. , Troup John P. , Unsworth Brian R. 
Published: January 2005

AbstractThe effects of thyrotoxicosis on the contractile properties and development of muscle fatigue in the slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles were examined in rats given 3 mg of L‐thyroxine and 1 mg of L‐triiodothyronine per kilogram of diet for 6 weeks. The hormone treatment produced significant decreases in the contraction time, one‐half relaxation time, and twitch tension in the SOL, while the peak rate of tension development (+ dP/dt) and decline (− dP/dt) in this muscle were elevated. Additionally, the forcefrequency curve was shifted to the right and, thus, resembled the curve of a normal fast‐twitch muscle. In contrast, the contractile properties of the fast EDL were relatively unaltered by the hormone administration. Thyrotoxicosis also changed the SOL response to contractile activity as twitch tension, + dP/dt, and − dP/dt remained high, and a faster decline in muscle glycogen and an increase in lactate occurred compared to control muscles. These results clearly demonstrate a preferential effect of thyroid hormone on slow compared to fast skeletal muscle.
Clinical investigation in duchenne muscular dystrophy: IV. Double. Blind controlled trial of leucine
Authors: Mendell Jerry R. , Griggs Robert C. , Moxley Richard T. , Fenichel Gerald M. , Brooke Michael H. , Miller J. Philip , Province Michael A. , Dodson W. Edwin ,   CIID GROUP
Published: January 2005

AbstractNinety‐six patients with Duchenne muscular dystrophy (DMD) were randomized and placed either on placebo or oral leucine at a dose of 0.2 g per kg per day. Patients were evaluated using a protocol that measured muscle strength, joint contracture, functional grade and activity, and pulmonary function tests. After 1 month there was a transient but significant difference in the strength of the two groups, the treated group being stronger than the placebo group. At 6 months there was also a transient difference in joint contracture measurements. Analysis of the data showed that the difference between the groups for both these measurements could not be ascribed to a therapeutic effect of leucine but rather to an unexpected drop in the placebo group. This was recognized only because the slope of deterioration for these functions had been well documented during the natural history phase of the study. These results indicate that oral leucine failed to produce a therapeutic response over a 1‐year double‐blind, controlled trial.
Electrodiagnostic tests in the detection of malignant hyperthermia
Authors: Eng Gloria D. , Becker Matthew J. , Muldoon Sheila M. 
Published: January 2005

AbstractMalignant hyperthermia (MH) can be a catastrophic and sometimes fatal reaction in certain susceptible individuals who are exposed to skeletal muscle relaxants such as succinylcholine and/or certain inhalation anesthetics such as halothane. In an attempt to develop a safe, simple in vivo test to identify the at‐risk patients, repetitive nerve stimulation (RNS) and electromyographic (EMG) studies were performed on 9 patients with MH, 15 patients suspected of having MH, and 9 control subjects. Serial recordings were made following injections of caffeine sodium benzoate, succinylcholine, and halothane at the test site. Measurements were done on the amplitude of the evoked compound motor action potentials (CMAP), on RNS, and on the number of negative peaks of motor unit potentials (MUP) on maximum EMG recruitment. The results showed the effects of the drugs on amplitudes of the CMAPs to be significant (P < 0.001) in all three groups, but no significant differences were found among the groups (P = 0.93). The negative peaks of MUP on EMG recording showed a significant difference upon introducing succinylcholine (P < 0.001), and significant interaction effects of the treatment by the patient group. Preliminary comparisons of in vivo tests with in vitro contracture tests in nine patients showed good correlation.