bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinguishing paramyotonia congenita and myotonia congenita by electromyography
Authors: Subramony S. H. , Malhotra C. P. , Mishra S. K.
Published: January 2005

Compound muscle action potential (CMAP) amplitudes, response to 2 Hz nerve stimulation, response to exercise and electromyographic needle electrode examination findings from the thenar muscles of two patients with paramyotonia congenita were compared with those from two patients with dominantly inherited myotonia congenita in warm (34°C) and cold (20°C) states. Cold induced a significant fall in CMAP amplitude, induced/worsened a significant decremental response to 2 Hz stimulation, and virtually abolished myotonia and voluntary recruitment of motor unit potentials in patients with paramyotonia congenita; none of these occurred in myotonia congenita. Though exercise induced a mild fall in CMAP amplitude in both groups, postexercise fibrillations occurred only in patients with paramyotonia congenita. These findings serve to distinguish these two entities in the clinical electromyography laboratory.
Slowing of twitch of dystrophic mouse muscle is partially due to altered activity pattern
Authors: Parry David J. , Desypris George
Published: January 2005

Fast‐twitch muscles of the hindlimb of dystrophic (dy2J) mice show a prolongation of both the contraction and relaxation phases of the isometric twitch. Comparable muscles of the forelimb of these mice exhibit relatively little increase in time to peak tension but time to half‐relaxation is as severely affected as in the hindlimb. When examined with an immunohistochemical technique to demonstrate the presence of “slow” myosin it was apparent that there were no fibers containing the “slow” isoenzyme in either hindlimb or forelimb muscles of 6‐month control mice. In dy2J mice hindlimb muscles contained many fibers with “slow” myosin whereas forelimb muscles did not. It is suggested that the spontaneous twitching activity produced in the hindlimbs, as a result of amyelination of the spinal roots, induces synthesis of “slow” myosin, which in turn leads to prolongation of time to peak twitch tension.
Content of methylhistidines in normal and pathological human skeletal muscles
Authors: Mussini Emilio , Cornelio Ferdinando , Dworzak Federica , Cotellessa Laura , Morandi Lucia , Colombo Laura , De Ponte Gloria , Marcucci Franca
Published: January 2005

The content of 3‐methylhistidine (3‐MH) and 1‐methylhistidine (1‐MH) was measured in muscle biopsy specimens from 13 normal controls, 19 patients with Duchenne muscular dystrophy, 8 limb‐girdle disease patients, and 23 disease controls with different forms of muscular pathology. 3‐MH and 1‐MH concentrations in normal human muscle did not appear to be influenced by sex, body weight, and age, at least for subjects in the 10–60 year age group examined. Skeletal muscle 1‐MH levels did not significantly differ from mean control values in any of the pathologies investigated. In the patient population examined, the mean 3‐MH level per unit of noncollagen protein (NCP) was significantly lower than normal in Duchenne dystrophy only, the reduction being related to disease severity. The significantly lower concentrations of 3‐MH in muscle of Duchenne patients indicate the importance of measuring 3‐MH in diseased muscle to obtain reliable estimates of the myofibrillar protein catabolic rate.
Changes in elemental composition of single muscle fibers following tenotomy of the rat soleus muscle
Authors: Wróblewski Romuald , Edström Lars
Published: January 2005

Cores were produced in type 1 muscle fibers by tenotomy of rat soleus muscle. The morphology and histochemistry of the muscle fibers was established by light microscopy on cryostat sections stained for hematoxylin‐eosin or myofibrillar ATPase and on semithin plastic sections. The ultrastructure was visualized on thin plastic sections. On 6 μm of freeze‐dried cryosections, energy dispersive X‐ray microanalysis was performed on muscle fibers visualized in the scanning transmission mode of electron microscopy. This procedure permitted quantification of different intracellular elements such as sodium (Na), chlorine (CI), potassium (K), magnesium (Mg), sulphur (S), and phosphorus (P). Spectra from core fibers could easily be compared with those of normal fibers. A conspicuous finding was an increased Na and CI content and a decreased K content in core fibers compared to normal fibers. It is known that core fibers produced after tenotomy exhibit distinct changes in plasma membrane morphology similar to that found in Duchenne muscular dystrophy (DMD). The results in this study point to a change in normal intracellular ion composition which could be a result of a deficiency of mechanisms maintaining normal membrane ion gradients.
Malignant hyperthermia and related neuromuscular diseases: Caffeine contracture of the skinned muscle fibers
Authors: Takagi Akio , Sunohara Nobuhiko , Ishihara Tadayuki , Nonaka Ikuya , Sugita Hideo
Published: January 2005

Using the skinned fiber preparation, the response to caffeine was studied on the skeletal muscle of malignant hyperthermia or other neuromuscular diseases. The sensitivity to caffeine was increased in the muscle of malignant hyperthermia. The sensitivity also was increased in Duchenne muscular dystrophy or asymptomatic patients with raised serum creatine kinase activity. Judging from the interaction between caffeine and the contractile system, the abnormal response originated from the sarcoplasmic reticulum in malignant hyperthermia. In Duchenne muscular dystrophy, the contractile system also might be involved in the increased sensitivity. Since the disease spectrum presenting abnormal responses is broad, it is suggested that muscle fibers become sensitive to caffeine when they are degenerating or regenerating.
Maturational defect of regenerating muscle fibers in cases with duchenne and congenital muscular dystrophies
Authors: Miike Teruhisa
Published: January 2005

Immature fibers in Duchenne muscular dystrophy (DMD) and congenital muscular dystrophies (CMD) were compared with human fetal muscles and experimentally‐induced regenerating muscle fibers using the acridine orange (AO) technique on fluorescent microscropy and histochemical methods. Strong AO activity was observed on immature fibers in dystrophies and on experimentally‐induced fibers in the early stages of regeneration. These young fibers showed type 2C histochemical reactions on ATPase stains. Human fetal muscles failed to show these fibers which were seen in the muscular dystrophies and the experimental regenerating muscle. From these results it is concluded that immature fibers in muscular dystrophies are early stages of regenerating fibers and not maturationally arrested fetal muscle fibers. In addition, these immature fibers formed small groups composed of 10 to 50 fibers in muscular dystrophies and sometimes large groups in CMD. It is suggested that the investigation of immature fibers and their grouping is quite important for revealing the pathogenesis of the muscular dystrophies.
Hypothesis: Duchenne dystrophy viewed as a disturbance of nerve‐muscle interactions
Authors: Vrbova Gerta
Published: January 2005

The possibility that some features of Duchenne muscular dystrophy (DMD) can be explained as a disturbance of nerve‐muscle interaction during development is discussed. It is argued that the initial disturbance in DMD is due to a slower rate of maturation of skeletal muscle fibers. Normally, the maturation of the motor reflexes is closely followed by maturation of the muscle fibers. The possibility is considered that if muscle fibers mature more slowly than normal, they are not able to withstand the type of activity imposed upon them by the mature motoneuron. This applies mainly to the high frequency activity imposed on the fibers of motor units that are destined to become “fast.” Experimental evidence suggesting such a mechanism is presented.
Occasional survey. Needle biopsy of skeletal muscle: A review of 10 years experience
Authors: Edwards R. H. T. , Round J. M. , Jones D. A.
Published: January 2005

Over 1,000 needle biopsies have been carried out at University College Hospital in London. Needle biopsy has been used by us for histochemical and electron microscopic examination of muscle during the diagnosis and treatment of neuropathic and myopathic disorders, for the diagnosis of mitochondrial myopathies, to study the course of recovery in polymyositis, and for investigations into muscle changes in systemic lupus erythematosus (SLE) and other autoimmune conditions. We have developed a microprocessor system for the measurement of muscle fiber areas, and needle biopsy specimens provide suitable material for such measurements. We have also used needle biopsy specimens for studies of protein turnover using stable isotopes and for trace metal and electrolyte analyses. Needle biopsy is safe and rapid. As the patient usually experiences only minimal discomfort and thereis no permanent scar, repeat biopsies are well tolerated allowing follow‐up studies after treatment.
Emetine myopathy: Two case reports with pathobiochemical analysis
Authors: Sugie H. , Russin R. , Verity M. Anthony
Published: January 2005

We report two female patients with a history of alcohol abuse presenting with proximal painful muscle weakness following aversion therapy with emetine hydrochloride. Muscle biopsy of Case 1 showed a reversible floccular‐shaped loss of myosin ATPase and dehydrogenase, and accumulation of PAS positive material, and a normal lipid content. Repeat biopsy showed core change with no focal loss of myosin ATPase. In Case 2, muscle biopsy was taken 1 month after commencement of emetine therapy and revealed similar but milder changes to Case 1. Electron microscopy revealed Z‐band streaming with a decrease or loss of mitochondria. Sarcotubular systems appeared normal in shape and size. Anaerobic glycolysis on homogenate from the initial biopsy of Case 1 showed generalized reduction of lactate formation, which returned to normal in the repeat biopsy.
Bilateral carpal tunnel in childhood associated with Schwartz‐Jampel syndrome
Authors: Martínez A. Cruz , Arpa J. , Conde M. C. Pérez , Ferrer M. T.
Published: January 2005

The case of a 7‐year‐old girl, the only descendant of non‐con‐sanguineous parents, who presented typical features of the Schwartz‐Jampel syndrome and electrophysiological evidence of bilateral carpal tunnel is reported. Conventional electromyogram (EMG) showed persistent and continuous electrical activity and high frequency discharges elicited spontaneously by movement of the needle or after voluntary activation. Electrical silence after phenytoin therapy was sometimes seen. Single fiber electromyography (SFEMG) showed that high frequency discharges had a complex configuration and multiple components. Occasionally the discharges showed a progressive decrease in amplitude. Increased jitter was also found in some potential pairs that had been isolated under voluntary contraction after phenytion therapy. Motor and sensory conduction velocities on the median nerve were slowed bilaterally across the carpal tunnel. Bilateral carpal tunnel syndrome is an unusual condition in children and its clinical picture differs from that in adults. Carpal tunnel syndrome was not clinically suspected in the patient reported in this article and the diagnosis was confirmed by the conduction velocity study.
Effects of acrylamide and other sulfhydryl compounds in vivo and in vitro on staining of motor nerve terminals by the zinc iodide‐osmium technique
Authors: Kemplay Sheila , Cavanagh John B.
Published: January 2005

The zinc iodide‐osmium technique blackens motor nerve terminals by selectively staining synaptic vesicles. Intraperitoneal injections of acrylamide (30 mg/kg/day, 5 times each week) cause inhibition of staining by this technique so that approximately one third of the end‐plates in rat sternocostalis muscle are unstained after 24 hours, and by 17 days more than 70% are unstained. This is not associated with nerve fiber degeneration. A similar inhibition of staining can also be shown after prior incubation of the sternocostalis muscle in 4 mM acrylamide in oxygenated Ringer's solution. Intraperitoneal injection of the thiol group blocker N‐ethylmaleimide also causes marked inhibition of staining of motor end‐plates by this method. Dithiothreitol, which prevents the oxidation of thiol groups, will partly prevent the inhibition of staining by both acrylamide and N‐ethylmaleimide, when given in vivo.
Enzyme activities and activity profiles in muscle fibers of dystrophic, immature‐normal, and adult‐normal BL6 mice
Authors: Reichmann Heinz , Pette Dirk
Published: January 2005

Enzyme activities of energy metabolism were determined in both homogenates and single fibers of immature‐normal (IN), adult‐normal (AN), and adult‐dystrophic (AD) tibialis anterior (TA) muscle of BL6 mice. Mitochondrial enzyme activities were similar in AN and AD, whereas lower activities were found in IN. Creatine kinase, glycogenolytic, and glycolytic enzyme activities were reduced but glucose 6‐phosphate dehydrogenase was elevated in AD and IN as compared to AN. IN and AD both showed an increase in the H‐subunit of lactate dehydrogenase. Microphotometric measurements of succinate dehydrogenase (SDH) revealed large fiber differences in AN whereas smaller scattering was observed both in IN and AD. Although similarities exist between enzyme and isozyme patterns of anaerobic metabolism in AD and IN, this does not hold for mitochondrial enzymes.
Electrophysiological diagnosis of interdigital neuropathy of the foot
Authors: Oh Shin J. , Kim Hyun S. , Ahmad Bashiruddin K.
Published: January 2005

We have devised a method of sensory nerve conduction in the interdigital nerves of the foot using the near‐nerve needle and signal averaging techniques. In 40 normal controls between the ages of 20 and 59, there was no difficulty in recording sensory compound nerve action potential (CNAP) in the various interdigital nerves. The amplitude of sensory CNAP ranged from 0.4–8.8 μV. The mean maximum nerve conduction velocities ranged from 33.3–40.5 M/second. In the group between 50–59 years old, nerve conduction changes due to aging were noted. In five patients with interdigital neuropathy (IDN) of the foot, a selective marked decrease in the amplitude of the CNAP in the involved interdigital nerve (“abnormal dip phenomenon”) was the most characteristic electrophysiological finding. The present technique is capable of recording the sensory CNAPs in the interdigital nerves of the foot and confirming the diagnosis of IDN electrophysiologically.
A technique for studying the greater auricular nerve conduction velocity
Authors: Palliyath Sarala K.
Published: January 2005

A technique for studying sensory nerve conduction velocity of the greater auricular nerve according to one of the conventional methods is described. Latency and conduction velocities obtained from 35 nerves in 20 healthy adults were 1.7 ± 0.2 msec (SD) and 46.8 ± 6.6 m/sec (SD), respectively. This technique is easy to perform and is useful in documenting traumatic and other neuropathies involving the greater auricular nerve, as illustrated in the case report in this article.
Lambert‐eation myasthenic syndrome
Authors: Jablecki Charles
Published: January 2005

This review of the Lambert‐Eaton myasthenic syndrome (LEMS) emphasizes electrodiagnosis and includes a case report. A 50‐year‐old woman had become progressively weaker over 1.5 years. The suspected diagnosis was confirmed by the clinical electrophysiological findings and was made 6 months before the patient's oat‐cell carcinoma was found. After treating with local radiation and chemotherapy, the myasthenic syndrome went into remission as the pulmonary lesion resolved.
Increased myofibrillar protein catabolism in duchenne muscular dystrophy measured by 3‐methylhistidine excretion in the urine
Authors: Mussini Emilio , Cornelio Ferdinando , Colombo Laura , de Ponte Gloria , Giudici Giovanni , Cotellessa Laura , Marcucci Franca
Published: January 2005

Myofibrillar protein catabolic rate was calculated in 50 young patients with Duchenne muscular dystrophy from the amount of 3‐methylhistidine excreted in the urine, and was found to be about seven times that of a control series, expressed as the percentage of myofibrillar protein catabolized per day. This wastage of myofibrillar protein is a consequence of Duchenne muscular dystrophy and inhibition of protein degradation appears to be one possible approach in the treatment of this disease.
Heterogeneity of spectrin distribution among avian muscle fiber types
Authors: Menold Marisa M. , Repasky Elizabeth A.
Published: January 2005

Muscle spectrin has been examined in avian fast, slow, and mixed muscles using the techniques of immunofluorescence microscopy and immunoautoradiography. By immunofluorescence, fibers of the fasttwitch pectoralis major (PM) are seen to contain α‐spectrin antigen primarily at the sarcolemma, while in the slow‐tonic anterior latissimus dorsi (ALD), α‐spectrin antigen is found in high concentrations throughout the sarcoplasm as well as being present in association with the sarcolemma. In mixed (fast‐ and slow‐twitch) muscles of the leg, two populations of fibers can be distinguished: those which resemble the fibers of the PM and another group which displays interior staining similar to the fibers of the ALD. Histochemical staining for actomyosin ATPase reveals that the fibers of mixed muscles which contain the most spectrin antigen correspond to the slow‐twitch fibers. Supportive data were obtained using sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) followed by immunoautoradiography. In slow muscle, an approximate threefold increase in α‐spectrin concentration relative to other proteins is evident. These results suggest that the distribution of α‐spectrin may be modified by the physiological state of the myofiber.
Anion permeability of toad skeletal muscle incubated in plasma and ringer solution
Authors: Macchia Donald D. , Didelot Mary J. , Anderson W. Marshall
Published: January 2005

Isolated semitendinosus muscles of the toad were incubated in both Ringer solution and toad plasma for periods ranging from 45 to 170 minutes. The extracellular volume (ECV), as measured from the equilibrium distribution of 35SO42−, was found to increase (in gram extracellular (EC) water/gram wet weight) from 0.15 ± 0.01 to 0.20 ± 0.02 in muscles incubated in Ringer solution, whereas the ECV was found to remain constant in tissues incubated in plasma (0.16 ± 0.01 to 0.17 ± 0.01), for periods up to 170 minutes. Since the true ECV, as measured morphometrically, was found to remain unchanged for muscles incubated in Ringer solution for up to 3 hours, the data for these muscles were interpreted to represent a change in anion permeability of the cellular membranes in response to the absence of some plasma fraction from the Ringer solution (with an electrolyte composition and pH similar to that of plasma). When toad plasma albumin was added to the Ringer solution, in physiological concentrations, the ECV of the muscles was observed to remain relatively constant during the 3‐hour incubation period. This albumin effect on anion permeability was found to be albumin concentration‐dependent. Further, other sources of albumin were found to have varying degrees of effect on the anion permeability of toad muscle, with bovine albumin seving as the most acceptable substitute for toad albumin, when incubating semitendinosus muscles.
Increase in the amount of elongation factor 2 in chicken muscular dystrophy
Authors: Yoshikawa Akira , Takano‐Ohmuro Hiromi , Masaki Tomoh
Published: January 2005

The amount of elongation factor 2 (EF2) in the cytoplasm and ribosome of breast muscle cell from normal and dystrophic strains of chicken was measured. Concentration in the cytoplasm of 20‐day‐old embryonic dystrophic muscle was higher than that in normal muscle, but no difference in content was found in muscles of 15‐day‐old embryos. The amount of EF2 bound to ribosomes was identical in normal and dystrophic muscles during all stages of development. Peptide mapping patterns of partial proteolytic fragments of EF2 from normal and dystrophic chicken breast muscles were similar. The increase in cytoplasmic protein synthetic activity of dystrophic breast muscles reported previously seems to be due to the corresponding increase in the number of EF2 molecules rather than to their modification in dystrophic muscle.
Electrical properties of commercial concentric EMG electrodes
Authors: Dorfman Leslie J. , McGill Kevin C. , Cummins Kenneth L.
Published: January 2005

Five electrical characteristics—impedance, broadband noise generation, line interference sensitivity, signal distortion, and common‐mode conversion—were measured in five electromyographic (EMG) concentric needle electrodes (CNEs) from each of six commercial manufacturers. Untreated CNEs showed considerable variation in impedance and broadband noise characteristics, both within and among manufacturers. Electrolytic treatment reduced impedances by a factor between 1.5 and 4.0 and lessene within manufacture variability Average post‐treatment impedances at 100Hz ranged from 31 to 436 kOhms, reflecting in part the range of core surface areas. Treatment also reduced the broadband noise to the level of the instrumentation noise for all but the highest impedance CNEs. Distortion and common‐mode conversion were negligible for the lowest impedance CNEs. Line interference from a nearby power cord was completely suppressed only by those CNEs with fully shielded cables, and then only when the electromyographer also was grounded; there was no measurable benefit when the shield was driven, as opposed to grounded. We conclude that (1) there are consistent differences in the properties of CNEs from different manufacturers, reflecting differences in materials, design, and construction; (2) electrolytic treatment temporarily improves the performance of all CNEs, and tends to lessen the differences among them, most likely through a surface electrochemical effect; and (3) both active and passive cable shields are effective in reducing extraneous line interference.
Free‐energy carriers in human cultured muscle cells
Authors: Bolhuis P. A. , de Zwart H. J. D. , Ponne N. J. , de Jong J. M. B. V.
Published: January 2005

Creatine phosphate (CrP), adenosine triphosphate (ATP), creatine kinase (CK), adenylate kinase (AK), protein, and DNA were quantified in human muscle cell cultures undergoing transition from dividing myoblasts to multinucleate myotubes. CrP is negligible in cultures grown in commonly applied media but increases rapidly when sufficient exogeneous creatine is available. The rise in CrP content precedes the rapid increase of CK and cessation of DNA synthesis found during cell fusion. The addition of creatine has no significant effect on the CK and protein content and on the fusion of the human muscle cells. ATP, AK, and protein increase gradually during proliferation and differentiation. When expressed per milligram of protein, ATP and AK are in the same range as in human skeletal muscle and are not correlated to the cell fusion. In contrast, CrP and CK per milligram protein are much higher in myotubes than in myoblasts but remain much lower than in muscle. These data indicate that only an early differentiation phase has been reached in the muscle cell cultures.
Endoneurial potassium is increased and enhances spontaneous activity in regenerating mammalian nerve fibers—implications for neuropathic positive symptoms
Authors: Low Phillip A.
Published: January 2005

The endoneurial fluid potassium [K+]e has potent effects on membrane potential and excitability but direct measurements have not been reported. The [K+]e was measured with K+ ion‐sensitive microelectrodes in normal, demyelinated, and regenerating rat peripheral nerve fibers. The mean value in normal nerve was 3.7 mM. The [K+]e was consistently elevated in regenerating nerves and infrequently elevated in demyelinated nerves. The time course of [K+]e was studied in the left tibial nerve of 22 rats 2 days to 3 months in the extended crush model. The [K+]e was increased and peaked in the first 2 weeks, with a progressive decline toward control values after that. Single fiber recordings were made from the tibial division of the sciatic nerve in 13 animals. The mean number of single fibers studied per rat was 55.5 (SD 24.6). Spontaneous activity (SA) was present in all regenerating nerves and was maximal in the first 2–4 weeks. Endoneurial K+ was further increased by intraarterial injection of potassium into the saphenous artery. Spontaneous activity was enhanced when [K+]e began to rise; there were further superimposed bursts of SA with the administration of additional boluses. These findings suggest that [K+]e increase is a factor in enhancing SA in damaged nerve fibers.
Acoustic myography: A noninvasive monitor of motor unit fatigue
Authors: Barry Daniel T. , Geiringer Steven R. , Ball Richard D.
Published: January 2005

Acoustic myography is the recording of sounds produced by contracting muscle. These sounds become louder with increasing force of contraction. We have compared muscle sounds with surface EMG to monitor the dissociation of electrical from mechanical events (presumably, the loss of excitation–contraction coupling) which occur with motor unit fatigue. Acoustic signals were amplified using a standard phonocardiograph, recorded on FM magnetic tape, and digitally analyzed. Muscles were examined at rest, with intermittent contractions, and with sustained contractions. We found that with fatigue, the acoustic amplitude decayed, but the surface EMG amplitude did not. With decreased effort, however, the acoustic and the surface EMG amplitudes declined simultaneously. By simultaneously recording acoustic signals and needle EMG, individual motor units were resolved acoustically in two muscles with decreased numbers of motor units and increased motor unit size. Fasciculations also produced acoustic signals, although no acoustic signal has yet been found that correlates with fibrillations. Analysis of acoustic signals from muscle provides a noninvasive method for monitoring motor unit fatigue in vivo. It may also be useful in distinguishing muscle fatigue from decreased volition.
Acquired versus familial demyelinative neuropathies in children
Authors: Miller Robert G. , Gutmann Ludwig , Lewis Richard A. , Sumner Austin J.
Published: January 2005

The electrophysiologic differences between chronic acquired demyelinative neuropathy and the demyelinative form of Charcot‐Marie‐Tooth disease have recently been reported. The present report extends these observations to include the genetically determined demyelinating neuropathies seen in metachromatic leukodystrophy, Krabbe's leukodystrophy, and Cockayne's syndrome. The electrophysiologic features of metachromatic leukodystrophy (five patients), Krabbe's (four patients), and Cockayne's syndrome (three patients) were all similar. There was uniform slowing of conduction (both in different nerves and in different nerve segments), and conduction block was not seen. These findings are consistent with a uniform degree of demyelination in multiple nerves and throughout the entire length of individual axons. Thus, uniform slowing of nerve conduction constitutes strong evidence for a familial demyelinative neuropathy, as opposed to the multifocal slowing seen in acute and chronic acquired demyelinative neuropathy.
Response of satellite cells to focal skeletal muscle injury
Authors: Schultz Edward , Jaryszak Debra L. , Valliere Charles R.
Published: January 2005

The time course and pattern of the initiation of satellite cell mitoses was studied following a crush injury of the distal third of the 30‐day‐old rat extensor digitorum longus, a muscle in which myofibers run the entire length of the belly. Satellite cell mitotic activity was monitored using autoradiography after injection of 3H‐thymidine. Satellite cell labeling rose above control values by 15 hours post injury at the injured site and by 20 hours in the middle third or adjacent undamaged portion of the muscle. Labeling decreased in the proximal third of the muscle, so that by 25 hours post injury, a gradient of labeling was established along the muscle length. Electron microscopy (EM) quantitation showed that the reduced labeling in the proximal third resulted from a reduction in satellite cell numbers. The results suggest that mitotic activity of satelite cells after localized injury occurs mainly at or near the site of injury, but that many of the dividing cells have migrated from undamaged areas distant from the lesion site.
Lysosomal changes in mouse skeletal muscle during the repair of exercise injuries
Authors: Salminen Antero , Kihlström Markku
Published: January 2005

Lysosomal changes of mouse skeletal muscle during the repair of exercise injuries were studied with biochemical, histochemical, and electron microscopic methods. Treadmill running for 4 hours and 9 hours increased the activities of cathepsin C and β‐glucuronidase, but not that of β‐glycerophosphatase in mouse quadriceps femoris muscle. The highest activities occurred 3 days after exertion and were higher after the longer duration of exertion. Similar changes that were highly correlated with the activities of lysosomal enzymes occurred in the activities of glucose‐6‐phosphate dehydrogenase and 6‐phosphogluconate dehydrogenase and in the concentration of DNA. The activities of lysosomal enzymes correlated significantly with the severity of histopathologic injuries. Histochemical stainings of β‐N‐acetylglucosaminidase and β‐glucuronidase showed a strong increase in the staining intensity 3 and 5 days after exertion, both in inflammatory phagocytes and in surviving muscle fibers in the injured area, and staining intensities increased in parallel with the severity of injuries. Electron microscopy showed an increased number of autophagic vacuoles, lysosomelike bodies, and Golgi complexes in the fibers adjacent to necrotic foci, coinciding with the highest histochemical staining pattern. Lysosomal changes in surviving muscle fibers in close proximity to injured muscle fibers could, by autophagic degradation, provide structural elements for the regeneration of injured muscle fibers.
The free cytoplasmic Ca2+ levels in duchenne muscular dystrophy lymphocytes
Authors: Klip Amira , Elder Brian , Ruiz‐Funes Hugo P. , Buchwald Manuel , Grinstein Sergio
Published: January 2005

An increased cellular Ca2+ content has been associated with Duchenne muscular dystrophy (DMD). However, estimates of the free cytoplasmic Ca2+ concentration ([Ca2+]i) in cells of DMD patients were not available. We compared the [Ca2+]i levels of normal and DMD peripheral blood lymphocytes and Epstein‐Barr virus‐transformed lymphoblasts using the novel probe, quin 2, an internally trapped fluorescent indicator. The [Ca2+]i levels of normal and DMD cells were not significantly different.
Fatigue trends in and the diagnosis of myasthenia gravis by frequency analysis of EMG interference patterns
Authors: Yaar Israel , Mitz Andrew R. , Pottala Erik W.
Published: January 2005

Twenty patients with myasthenia gravis were studied. Needle interference patterns at maximal isometric contractions were recorded from the biceps brachii muscles. Each recording lasted for 30 seconds and induced som fatigue. The EMG signals were transformed into power spectra and were analyzed for differences between control and myasthenic fatigue trends and were tested for the power of the frequency variables to classify unknown subjects. Both groups showed a similar averaged spectra for the first 5 seconds. Thereafter, the controls manifested continuous increase in power, and a power peak frequency shift toward low frequencies. The myasthenics showed an initial increase throughout the frequency ranges; however, later, there was a marked decrease in power and their peak frequency shifted toward the lower frequencies. These fatigue trends differed significantly from one another. Discriminant analysis correctly classified 83% of the subjects. This technique may be helpful in the diagnosis of myasthenia gravis.
Evidence for the identities of five proteins decreased in skeletal muscle of dystrophic mice
Authors: Jasch Laura G. , Moase Elaine H.
Published: January 2005

In a previous study,16 protein distributions in normal and dystrophic soleus and EDL were examined using polyacrylamide isoelectric focusing. Whereas normally protein distributions in these two muscles were characteristically different, in dystrophic muscles they were strikingly similar. The soleus‐specific proteins were identified as the myosin light chains LC1s and LC2s. The EDL‐amplified proteins were the myosin light chains LC1f, LC2f, the phosphorylated form of LC2f (LC2f‐P), and LC3f. In addition, evidence is presented that one protein, which had not been identified in two‐dimensional gels, is parvalbumin. The decreased proportion of parvalbumin, LC2f‐P, and LC3f in the dystrophic EDL was also shown in other fast‐twitch muscles of the mouse. We suggest that these changes in protein distributions in dystrophic muscles reflect a loss of their acquired state of differentiation.
Regeneration of frog twitch and slow muscle fibers after mincing
Authors: Schmidt Heinz , Emser Wendelin
Published: January 2005

Iliofibularis muscles of Rana temporaria were minced and allowed to regenerate in the iliofibularis or the sartorius bed of the same frog. Regenerated muscles were examined for the presence of slow muscle fibers using electrophysiologic, histochemical, and contractile parameters. Muscle regeneration from sartorius mince was also studied. Regeneration was more successful from iliofibularis than from sartorius mince, and the iliofibularis bed was more favorable for regeneration than the sartorius bed for both types of muscle. Twitch fibers regenerated within a few months, but slow fibers could not be identified earlier than 14 months after muscle destruction. Slow muscle fibers regenerated only from iliofibularis mince, both orthotopically and heterotopically. All regenerates capable of maintaining a K‐contracture contained histochemically identified slow fibers; the membrane properties of electrophysiologically identified slow fibers were normal. It is concluded that slow muscle fibers regenerate only from the remnants of a muscle that contains slow fibers. The results are discussed with respect to the role of innervating nerve fibers.
Postpoliomyelitis muscle pseudohypertrophy
Authors: Bertorini Tulio E. , Igarashi Masanori
Published: January 2005

A 62‐year‐old patient who had had acute paralytic poliomyelitis in early childhood developed bilateral lower limb muscle pseudohypertrophy. The pseudohypertrophy was caused primarily by an enormous excess of adipose tissue replacing muscle fibers, and, in part, by work hypertrophy of muscle fibers.
Beta‐oxidation enzymes in normal human muscle and in muscle from a patient with an unusual form of myopathic carnitine deficiency
Authors: Trevisan Carlo P. , Reichmann Heinz , DeVivo Darryl C. , DiMauro Salvatore
Published: January 2005

In a reported patient with myopathic carnitine deficiency, addition of exogenous carnitine to muscle homogenates failed to correct palmitate oxidation, and oral carnitine was of no clinical benefit.27 In a muscle biopsy from this patient, we found that, in contrast to the marked deficiency of free carnitine (3% of normal) short‐ and medium‐chain acylcarnitines were in the normal range and long‐chain acylcarnitine was increased almost four times. As this result confirmed the hypothesis of a muscle defect of mitochondrial oxidation of palmitate, all eight enzymes of beta‐oxidation were measured spectrophotometrically in the muscle extract. None of them was found to be defective. These data suggest that the underlying biochemical abnormality in this patient may be a deficiency of the carnitine–acylcarnitine translocase system or a defective interaction between acyl‐CoA dehydrogenase and its flavoprotein coenzyme.
Tissue culture studies of muscle disorders: Part 1. Techniques, cell growth, morphology, cell surface
Authors: Witkowski J. A.
Published: January 2005

Tissue culture has been used extensively in studies of human inherited disorders, and its application in the field of the neuromuscular disorders has increased rapidly in recent years. This review, covering the period 1977 to 1984, deals with tissue culture studies of both human and animal muscle disorders, although Duchenne muscular dystrophy (DMD) figures prominently because of the overwhelming interest in that disorder. The review is in two parts. In the first part, I discuss technical innovations in the field, the morphology and growth of cells, and a variety of studies related to the cell surface. Important findings in relation to DMD include reports of abnormal growth rates and reduced lifespan of DMD cells, hypersensitivity to DNA‐damaging agents, abnormal cell‐to‐cell and cell‐to‐substratum adhesion, and a more “fluid” cell membrane. However, these findings are controversial or have so far been reported only by single laboratories.
Tissue culture studies of muscle disorders: Part 2. Biochemical studies, nerve‐muscle culture, metabolic myopathies, and animal models
Authors: Witkowski J. A.
Published: January 2005

This review continues with studies of protein, lipid, and purine metabolism of Duchenne muscular dystrophy (DMD) cells in vitro and of muscle cells in combined culture with nerve cells. In vitro studies of human metabolic myopathies are tabulated. Results using the hamster, chicken, and mouse (dy25, dy, mdg, and mdx) myopathies are discussed. Interesting findings include suggestions of altered collagen synthesis by DMD cells. Analysis of cell proteins by two‐dimensional gel electrophoresis and the use of combined nerve‐muscle cultures remain important areas of development. It is disappointing that so few attempts have been made to repeat significant findings in this field, and when a number of laboratories have examined the same phenomenon, the results are often contradictory. It remains to be shown how these various abnormalities found in cells in vitro are related to each other and to those pathologic features of diseased muscle observed in vivo.
Effector mechanisms in myasthenia gravis: End‐plate function after passive transfer of IgG, Fab, and F(ab′)2 hybrid molecules
Authors: Sterz Raimund , Hohlfeld Reinhard , Rajki Klara , Kaul Martin , Heininger Kurt , Peper Klaus , Toyka Klaus V.
Published: January 2005

Using the quantitative ionophoresis technique and the mouse passive transfer model of myasthenia gravis, end‐plate function was measured in mice transferred with myasthenic lgG, Fab, or F(ab')2 hybrid molecules prepared by recombination of one acetylcholine receptor (AChR) specific Fab and one Fab directed against irrelevant antigen. The Hill coefficient (a measure for the cooperativity between AChR subunits) and the apparent dissociation constant K for the ACh‐AChR interaction were essentially unaltered after passive transfer of lgG or lgG fragments. In contrast, myasthenic lgG and Fab, but not control lgG or Fab, markedly reduced the mean number of end‐plate channels. A similar effect was observed after passive transfer of F(ab')2 hybrid molecules. These results show that passive transfer of myasthenic lgG or lgG fragments leads to a quantitative reduction of ACh‐controlled end‐plate channels, whereas the function of the remaining receptors/channels remains unchanged. The results suggest further that crosslinking of AChR by divalent antibody may not be an absolute requirement for the reduction of AChR at the functional neuromuscular synapse.
Promiscuous expression of myosin in myotonic dystrophy
Authors: Moore Gudrun E. , Roses Allen D. , Pericak‐vance Margaret A. , Garrett William E. , Schachat Frederick H.
Published: January 2005

The pathologic changes in myotonic dystrophy (DM) skeletal muscle biopsies have been analyzed at both the histochemical and molecular level. A histochemical stain for pretyping single fibers in conjunction with sodium dodecyl sulphat—polyacrylamide gel electrophoresis allowed biochemical differences to be pinpointed in specific histochemical fiber types. These biochemical differences can be related to histochemical changes in fiber type observed in cross‐section of the DM biopsies. Such changes included, specific fiber type atrophy, hypertrophy, and disproportion. The pathogenesis of DM appears to be characterized by a large increase in the number of promiscuous fibers, that is, those fibers that express both fast and slow myosins. This promiscuity, which is rare in control muscle (<2%), is also prevalent at high levels in some family members at risk for DM. The observed promiscuity, although probably not a primary effect of DM, appears to be linked to the histochemical changes in fiber type observed in the DM biopsies.
Delayed nerve regeneration in streptozotocin diabetic rats
Authors: Longo F. M. , Powell H. C. , Lebeau J. , Gerrero M. R. , Heckman H. , Myers R. R.
Published: January 2005

Nerve regeneration across a 10‐mm gap was delayed in streptozotocin diabetic rats 3 and 4 weeks after transecting the sciatic nerve. Opposite ends of each cut nerve were introduced into a silicone tube, leaving a 10‐mm gap. Electron microscopy was used to evaluate the progress of regeneration in sections at 2‐mm intervals across the 10‐mm gap. After 3 weeks, control axons had bridged the 10‐mm gap, and myelin sheaths extended for 6–8 mm. By contrast, axons and their myelin sheaths were seen no further than 2 mm from the proximal stump in diabetic animals. By 4 weeks, axons had bridged the gap in diabetics; however, they appeared immature and showed dystrophic changes. The findings suggest that although regeneration does occur in diabetic nerves, it is significantly delayed and qualitatively impaired.
Skeletal muscle acetylcholinesterase molecular forms in amyotrophic lateral sclerosis
Authors: Fernandez Hugo L. , Stiles Joel R. , Donoso J. Alejandro
Published: January 2005

Acetylcholinesterase (AChE) molecular forms in muscle biopsies from control and amyotrophic lateral sclerosis (ALS) patients were extracted under low (G: globular forms) and high (A: asymmetric forms) ionic strength conditions and were evaluated by velocity sedimentation analysis. Total AChE activity in endplate‐containing ALS muscle sections was reduced by an average of 65% of control muscle levels. This decrement resulted from an almost complete disappearance of 9.5S (G4) and 8.0S (A4) AChE and significant decreases in the 3.8S (G1), 12.1S (A8), and 15.8S (A12) forms (66%, 9%, and 25% of control, respectively). In most of the ALS biopsies examined, ultrastructural‐cytochemical analysis revealed large reductions in AChE reaction product of both synaptic infoldings (extracellular) and sarcoplasmic reticulum (intracellular) of the muscles' motor endplate regions. These data are compatible with the view that alterations observed in AChE forms from ALS muscles are related to disturbances in the normal “trophic” interactions between nerve and muscle.
Ganglioside therapy in diabetic neuropathy
Authors: Horowitz Steven H.
Published: January 2005

Cronassial, a combination of four different cerebral gangliosides, was administered intramuscularly (40 mg daily) in a double‐blind controlled study of 28 patients with moderate to severe diabetic neuropathy. Clinical neurologic and near‐nerve electrophysiologic studies were performed. The 14 patients receiving gangliosides experienced statistically significant improvement in their clinical scores due to an increase in lower extremity sensory perception. No other clinical or electrophysiologic changes were present. No side effects were noted. Further studies employing greater numbers of patients and higher doses are required to confirm the efficacy of gangliosides in diabetic neuropathy.
Normal and dystrophic hamster myoblast and fibroblast growth in culture
Authors: Klamut Henry J. , Lin Chao‐Hsiung , Strickland Kenneth P.
Published: January 2005

Normal and dystrophic hamster myoblasts and fibroblasts were compared for characteristic indicators of growth and differentiation. Clonal analysis of myoblast cultures indicated that 80% of colonies judged to be fusion‐competent had differentiated. Dystrophic myoblasts were identical to normal in terms of their morphology, fusion potential (81.4%), and myokinase activity (59.6–49.1 mU/mg at 2–7 days), but displayed a significantly higher plating efficiency (normal: 52.6%; dystrophic: 82.1%), a longer doubling time (normal: 21.7 hours; dystrophic: 33.3 hours), and a lower day‐7 creatine kinase activity (normal: 60.7 mU/mg; dystrophic: 41.3 mU/mg). Dystrophic fibroblasts were indistinguishable from normal ones in terms of their morphology, plating efficiency (90.4%), and doubling time (32.5 hours), but displayed a significantly lower day‐2 creatine kinase activity (normal 58.3 mU/mg; dystrophic: 35.8 mU/mg) and day‐7 myokinase activity (normal: 52.7 mU/mg; dystrophic: 39.9 mU/mg). The results are suggestive of an early and differential expression of the primary defect in dystrophic hamster myoblasts and fibroblasts in culture.
Improved motor response due to chronic electrical stimulation of denervated tibialis anterior muscle in humans
Authors: Valenčič V. , Vodovnik L. , Štefančič M. , Jelnikar T.
Published: January 2005

Nine patients with complete denervation of the tibialis anterior were admitted to a stimulation program in order to restore dorsiflexion of the foot. Best results were obtained with pulses of 20‐msec pulse width and 20‐msec interval. After 3 weeks of training for 2 × 20 min/day, dorsiflexion due to stimulation was increased in all patients. In some of them, gait could be improved during the swing phase using electrical stimulation. The applied training program thus reversed the course of disuse atrophy and proved the feasibility of functional electrical stimulation for patients with denervated muscles.
Compressive neuropathy in childhood: A report of 14 cases
Authors: Jones H. Royden
Published: January 2005

During a 6‐year period, 14 of 898 patients examined at a pediatric electromyographic laboratory had a compressive mononeuropathy. These included five injuries to the peroneal nerve, four to the sciatic nerve, two to the distal radial nerve, and one each to the deep palmar branch of the ulnar nerve, the musculocutaneous nerve, and the long thoracic nerve. A potentially preventable mechanism was identified in 9 of the 14 patients, including prolonged posture in three of the four sciatic and two of the peroneal neuropathies. Four other mononeuropathies were secondary to pressure from an orthopedic appliance or procedure (one injury to the musculocutaneous nerve, one to the long thoracic nerve, two to the peroneal nerve).
Improvement of screening in exertional myalgia with a standardized ischemic forearm test
Authors: Sinkeler Sietze P. , Wevers Ron A. , Joosten Ed M. , Binkhorst Rob A. , Oei Lian T. , van'thof Martin A. , de Haan Anton F.
Published: January 2005

An ischemic forearm test with simultaneous measurement of both lactate and ammonia can be used as a screening method for myoadenlyate deaminase deficiency (MADD) and for various glyco(geno)lytic defects. A standardized and a nonstandardized test have been compared in a group of 186 patients with exertional myalgia. Standardization of the ischemic forearm test has led to greater yields of both lactate and ammonia in venous return blood of patients and controls. The sensitivity of the proposed test procedure in detecting MADD patients was 100%, whereas the specificity amounted to 98.8% among exertional myalgia patients.