bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical analysis of variability of muscle function measurements in duchenne muscular dystrophy
Authors: Edwards R. H. T. , Chapman S. J. , Newham D. J. , Jones D. A. BSc, PhD
Published: January 2005

To determine the possible sources of variation in performance indicators used in therapeutic trials, electrical stimulation techniques were used to measure contractile properties of the adductor pollicis and quadriceps muscles in boys with Duchenne muscular dystrophy. As no therapeutic effects were observed, longitudinal data obtained are taken to indicate changes in disease progress. Variance in voluntary contractions was found to be similar to that with electrically stimulated contractions; thus, variation could not be attributed to motivational changes, but rather to physiologic changes. Dystrophic muscle was slower to relax and less fatiguable than normal. However, such changes are of less significance to the overall disability compared to the loss of muscle bulk (cross‐sectional area). Important variations in the function of individual muscles essential to complex performance, such as walking or getting up from the floor, could be masked by combining results from several muscle groups.
Calcium‐activated protease activity in tenotomized muscle
Authors: Baker James H. , Margolis Ronald N.
Published: January 2005

The purpose of this study was to investigate the possible role of calcium‐activated neutral protease in the disorganization and dissolution of the myofibrils of the rat soleus that occurs following tenotomy. Rats were killed 3, 5, 7, 14, 21, and 42 days after tenotomy of the soleus, and the muscles were removed and assayed for calcium‐activated protease activity. Maximal protease activity occurred 1 week after tenotomy, at the time when myofibril organization is completely disrupted. Activity was still high 2 and 3 weeks after the operation, but returned to normal levels by 6 weeks, when muscle histology had returned to normal. The time course of the calcium‐activated protease activity corresponded closely to the time course of the morphological changes. Thus, calcium‐activated neutral protease may play a major role in myofibrillar proteolysis following tenotomy and in making the myofibril susceptible to proteolytic attack by other, less specific proteases.
Prevention of recurrent exertional rhabdomyolysis by dantrolene sodium
Authors: Haverkort‐Poels Petra J. E. , Joosten ED M. G. MD, PhD , Ruitenbeek Wim
Published: January 2005

A patient with recurrent attacks of exertional rhabdomyolysis and easy fatiguability was treated with dantrolene sodium. She experienced a complete prevention of myoglobinuric attacks and gained a better exercise tolerance. Biochemical findings in this patient suggest a loosely coupled oxidative phosphorylation in mitochondria. The question is raised as to whether dantrolene sodium exerts an effect on the mitochondrial calcium uptake and influences the state of coupling of the mitochondria.
Morphometric studies of sural nerve in childhood
Authors: Ouvrier Robert A. , McLeod J. G. , Conchin Therese
Published: January 2005

Sural nerve myelinated fiber density and myelinated fiber diameter distribution have been examined in 27 control subjects, ranging in age from 1 day to 59 years. Total transverse fascicular area was measured in 10 of the subjects. There is an exponential decline in myelinated fiber density from birth to adult life. The predicted normal density (D) at any age may be derived from the formula D = (1 × 103)/(0.0699 + 0.00725 √t). The distribution of myelinated fiber diameters is unimodal in the first 4 months of life, and there is a denfinite bimodal distribution by 2 years of age. Total transverse fascicular area of sural nerve increases progressively from values of about 0.25 mm2 in the first week to about 0.82 mm2 at 9 years. Control values for sural nerve morphometry in childhood are essential for accurate interpretation of biopsies in patients with peripheral neuropathy.
Localization of myoglobin in human muscle cells by immunoelectron microscopy
Authors: Kawai Hisaomi , Nishino Hiroshi , Nishida Yoshihiko , Masuda Kenjiro , Saito Shiro
Published: January 2005

The localization of myoglobin in human skeletal muscle cell was studied by immunoelectron microscopy. The Fab'‐horseradish peroxidase (HRP) conjugate was prepared by the maleimide method recently developed by Ishikawa et al. This method gave better recovery and less polymerization of HRP than the periodate method. By the direct immunoperoxidase method using this conjugate, myoglobin was shown to be localized in the I‐band region of skeletal muscle cells. The outer membrane of mitochondria and triads stained intensely, but A‐bands were not stained. Myonuclei and intermyofibrillar spaces were also not stained. The localization of myoglobin in the I‐band implies its function in energy generation.
Relative refractory period: A measure to detect early neuropathy in alcoholics
Authors: Alderson M. Kathryn , Petajan Jack H.
Published: January 2005

The absolute (ARP) and relative refractory period (RRP) of the median sensory nerve was determined in 26 control subjects and 24 alcoholics, nine of whom had symptoms of peripheral neuropathy. Recovery of latency to normal in response to the second stimulus was used to define RRP. A true RRP was calculated by subtracting ARP from measured RRP. Mean ARP for all subjects ranged from 0.75 to 0.80 msec; normal = 0.8 ± 0.2 msec. The true RRP of control subjects was 2.1 ± 0.5 msec, and for all alcoholic subjects it was 3.1 ± 0.5 msec. True RRP for the nine symptomatic alcoholic subjects was 3.6 ± 0.5 msec and 2.9 ± 0.4 msec for those who were asymptomatic. Symptomatic and asymptomatic alcoholics differed significantly from one another, as well as from control subjects (P < 0.001). Routine nerve conduction studies were normal in asymptomatic subjects. Three out of nine symptomatic alcoholics had increases in distal median motor or sensory latency, and three had slight slowing of median nerve conduction velocity. True RRP is more sensitive than routine measures of nerve conduction in the detection of axonal disorders influencing nerve conduction.
T‐Lymphocyte subsets, functional deficits, and morphology in sciatic nerves during experimental allergic neuritis
Authors: Strigård Karin , Olsson Tomas , Brismar Tom , Kristensson Krister , Klareskog Lars
Published: January 2005

Conduction velocities, demyelination, “macrophage/dendritic” cells, different sets of T‐lymphocytes, and immunoglobulins were estimated in sciatic nerves during various phases of experimental allergic neuritis in Lewis rats. Demyelination was minimal day 15 postimmunization (p.i) when conduction velocity already was reduced, somewhat more pronounced day 17 p.i. when nerve conduction was blocked, and most pronounced day 23 p.i. when nerve conduction partially had recovered. This suggests a dissociation between the degree of demyelination and the functional deficits. Decrease of sciatic nerve conduction velocities coincided with endoneurial appearance of T‐lymphocytes and “macrophage/dendritic” cells, as well as endoneurial immunoglobulins, day 15 p.i. Later partial functional recovery occurred in parallel with the disappearance of T‐cells. The degree of functional deficits thus correlated with the number of endoneurial T‐lymphocytes. T‐cells may, directly or indirectly, initiate several of the disease components in experimental allergic neuritis, including the nerve conduction deficit.
Benign focal amyotrophy: Metrizamide ct evidence of cord atrophy. Case report
Authors: Metcalf James C. , Wood James B. , Bertorini Tulio E.
Published: January 2005

Benign focal amyotrophy is an uncommon variant of neuron disease characterized by the gradual development of atrophy usually involving one upper extremity with a subsequent nonprogressive course. Previous descriptive reports have included normal radiological studies. We present a case of benign focal amyotrophy with a metrizamide CT myelographic finding of segmental cord atrophy in a distribution consistent with the patient's clinical findings.
Comparison of magnetic resonance imaging with somatosensory testing in ms suspects
Authors: Eisen Andrew , Odusote Kayode , Li David , Robertson William , Purvis Sherry , Eisen Kathleen , Paty Donald
Published: January 2005

Two hundred patients suspected of having multiple sclerosis (MS), including 42 with progressive myelopathy and 11 with optic neuritis, were investigated with somatosensory evoked potentials (SEPs) and magnetic resonance imaging (MRI). Most had minimal neurological deficit, the mean Kurtzke scale being 2.65. There were 117 patients had two or more MRI lesions suggestive of MS, with a total of 527 lesions identified; 290 (55%) involved the somatosensory pathways, most commonly lying in the mid‐periventricular region (thalamo‐cortical radiations). There was good correlation between positive and negative MRls and SEPs. The MRI was abnormal more frequently than the SEP, except in progressive myelopathy in when both were abnormal with equal frequency. It is proposed that some cases of myelopathy in MS may be due to periventricular rather than spinal pathology. The morphology of the MRI lesion would favor conduction block not slowing of the SEP as being the prime abnormality. This appeared to be true of leg SEPs.
Diagonal z‐lines: An unexplained electron microscopic finding
Authors: Isaacs Hyam , Whistler Toni
Published: January 2005

A patient suffering with myasthenia gravis was subjected to muscle biopsy of the deltoid and subsequently of the pectoralis muscle. Electron microscopic examination of the muscles revealed the scattered presence of Zlines that were curiously orientated diagonally across the I band. This appears to be a coincidental finding, the significance of which is unknown and unreported at this time.
Hemifacial spasm and facial myokymia: Electrophysiological findings
Authors: Horowitz Steven H.
Published: January 2005

In two patients, one with clinical hemifacial spasm (HFS) and one with clinical facial myokymia, the spontaneous electromyographic findings consisted of regular burst activity: each burst composed of high frequency repetitive motor unit potentials. These bursts fired synchronously in multiple ipsilateral facial muscles in both patients and from a contralateral facial muscle in the patient with HFS. In addition, the patient with HFS exhibited crossed evoked responses on the affected side with stimulation of the facial and supraorbital nerves on the unaffected side. It is concluded that the current electrophysiological distinctions between HFS and facial myokymia may be unsupportable and that facial nuclear hyperactivity with activation of bilateral facial nuclear connections plays a role in the pathophysiology of HFS.
Friedreich's ataxia: Electrophysiologic and histologic findings in patients and relatives
Authors: Caruso G. , Santoro L. , Perretti A. , Massini R. , Pelosi L. , Crisci C. , Ragno M. , Campanella G. , Filla A.
Published: January 2005

Peripheral nerve conduction velocity and cortical evoked potentials were investigated in 48 patients with Friedreich's disease and in 35 relatives. There were 14 patients and 2 relatives who underwent sural nerve biopsy.

In the patients sensory conduction velocity was moderately slowed, whereas sensory responses were markedly reduced. Nerve biopsy showed a severe loss of large myelinated fibers and no demyelination. On teased nerve fiber preparations, most fibers presented uniformly short internodes. No correlation was seen between sensory conduction findings or histologic abnormalities and clinical disability.

In patients SSEP changes, which were constant, and VEPs, which were frequently involved, were unrelated to the severity or duration of clinical disability.

The were 14 relatives who showed clinical signs of Friedreich's disease. Slightly decreased distal conduction velocity along sensory fibers was observed in more than half of the relatives. Nerve biopsy was noncontributory. In conclusion, we could not determine whether the abnormalities observed in the siblings were an expression of a heterozygotic condition, or whether they were early signs of the disease.
Hypogravity‐induced atrophy of rat soleus and extensor digitorum longus muscles
Authors: Riley Danny A. , Ellis Stanley , Slocom Glenn R. , Satyanarayana Tanjore , Bain James L. W. , Sedlak Frank R.
Published: January 2005

Prolonged exposure of humans to hypogravity causes weakening of their skeletal muscles. This problem was studied in rats exposed to hypogravity for 7 days aboard Spacelab 3. Hindlimb muscles were harvested 12–16 hours postflight for histochemical, biochemical, and ultrastructural analyses. The majority of the soleus and extensor digitorum longus fibers exhibited simple cell shrinkage. However, approximately 1% of the fibers in flight soleus muscles appeared necrotic. Flight muscle fibers showed increased glycogen, lower subsarcolemmal staining for mitochondrial enzymes, and fewer subsarcolemmal mitochondria. During atrophy, myofibrils were eroded by multiple focal losses of myofilaments; lysosomal autophagy was not evident. Tripeptidylaminopeptidase and calcium‐activated protease activities of flight soleus fibers were significantly increased, implying a role in myofibril breakdown. Simple fiber atrophy appears to account for muscle weakening during spaceflight, but fiber necrosis is also a contributing factor.
Characterization of a prostaglandin dysfunction myopathy
Authors: McLennan Ian S.
Published: January 2005

Inhibition of prostaglandin synthesis in chicken embryos generated a myopathy characterized by ringbinden, loss of Z disks and thick and thin filaments from the myofibrillar apparatus. During the early stages of myogenesis there was also abnormal clustering and contacts between the developing myotubes. This disruption of myofibrillar apparatus occurred in both primary and secondary myotubes. There was also a slight increase in the proportion of type 1 fibers, which resulted from a selective absence of type 2 fibers. The number of motoneurons in the lumbar spinal cord was normal. This, along with the nature of the disruption of the myofibrillar apparatus, was taken as an indication that the generation of this myopathy was not secondary to abnormal motoneuron development.
Effects of fatiguing exercise on high‐energy phosphates, force, and EMG: Evidence for three phases of recovery
Authors: Miller Robert G. , Giannini Don , Milner‐Brown H. S. , Layzer Robert B. , Koretsky Alan P. , Hooper Dana , Weiner Michael W.
Published: January 2005

Experiments were designed to evaluate the relative contribution of impulse propagation failure, high‐energy phosphate depletion, lowered pH, and impaired excitation‐contraction coupling to human muscle fatigue and recovery. 31P nuclear magnetic resonance spectroscopy measurements were made on adductor pollicis muscle, together with simultaneous measurements of M‐wave, force, and rectified integrated EMG (RIEMG). During fatigue, maximum voluntary contraction force (MVC) fell by 90%, pH fell from 7.1 to 6.4, and phosphocreatine was almost totally depleted. Neuromuscular efficiency (NME = force/RIEMG) was reduced to 40% of control at the end of the fatiguing contraction, and the M wave was reduced in amplitude and prolonged in duration. Following exercise, the M wave returned to normal within 4 minutes. pH, high‐energy phosphates, and MVC recovered within 20 minutes. By contrast, neuromuscular efficiency did not recover within 60 minutes. These findings indicate three different components of fatigue. The first is reflected by the altered M wave and indicates impaired muscle membrane excitation and impulse propagation. The second, associated with reduced MVC, correlates with the metabolic state of the muscle (PCr and pH). The third, indicated by reduced NME, is independent of changes in high‐energy phosphates and pH and is probably due to impaired excitation‐contraction coupling.
Trial of ganglioside therapy for diabetic neuropathy
Authors: Hallet Mark , Flood Thomas , Slater Norma , Dambrosia James
Published: January 2005

The efficacy of daily intramuscular injection of mixed gangliosides (Cronassial) for highly symptomatic diabetic neuropathy was investigated in a randomized double‐blind trial. There were 37 patients treated with 40 mg of gangliosides or placebo for 12 weeks and studied with physical examination, symptom scales, and electrophysiologic parameters. There was no demonstrated benefit of therapy. Given the spontaneous variation in the measurements employed, larger numbers of patients would have been needed to identify a significant change of 10% owing to therapy.
Thoracic outlet syndrome surgery causing severe brachial plexopathy
Authors: Wilbourn Asa J.
Published: January 2005

Hundreds of first rib resections are performed yearly in the United States to treat a controversial type of neurogenic thoracic outlet syndrome (NTOS). This surgery was thought to be devoid of serious neurological complications until 1982. However, that year Dale unearthed the rather astounding fact that the members of a single surgical society were aware of nearly 300 brachial plexus injuries resulting in motor deficits that had occurred during such operations, although almost none had been reported in the literature. In this report the features of the two main types of NTOS (“true” and “disputed”) are discussed. The history of brachial plexus injury occurring during TOS surgery is traced back to the late nineteenth century. The clinical and electrophysiological features of eight patients who sustained such injuries are described in detail, the literature on this topic is reviewed, and the location and causes for these injuries are discussed.
Axilla to elbow radial nerve conduction
Authors: Kalantri Ananthlal , Visser Bryan D. , Dumitru Daniel , Grant Arthur E.
Published: January 2005

Numerous techniques that evaluate radial nerve conduction from the axilla or supraclavicular fossa to the elbow have been reported. A shortcoming of most protocols is determining the precise radial nerve length as it proceeds along the spiral groove. The present study dissected out and measured directly eight cadaver radial nerves from the axilla to the elbow. These values were compared with a new surface tape measurement technique from axilla to elbow across the bicep muscle, obstetrical calipers over this region, and a surface determination approximating the course of the radial nerve posteriorly in the spiral groove. The anterior surface tape‐measuring procedure compared most favorably with the actual anatomic length. Nerve conduction velocities were then calculated in 20 volunteers using all 3 techniques and compared with the median nerve in the arm. The anterior and posterior tape measurements yielded a conduction velocity of 72.5 ± 4.7 and 86.6 ± 7.0 m/s, respectively, whereas the caliper resulted in 65.7 ± 3.9 m/s. We conclude that proximal radial nerve length assessment employing an anterior tape measurement from axilla to elbow across the bicep musculature is precise and compares favorably with the actual anatomic length of the radial nerve.
Stretch‐induced spinal accessory nerve palsy
Authors: Logigian Eric L. , McInnes Janice M. , Berger Alan R. , Busis Neil A. , Lehrich James R. , Shahani Bhagwan T.
Published: January 2005

Left spinal accessory nerve palsy occurred in a young man when he quickly turned his head to the right while his shoulders were pulled down by heavy hand‐held objects. Electrophysiologic studies demonstrated partial axonotmesis of the spinal accessory nerve branches innervating the sternocleidomastoid and upper and middle trapezius and complete axonotmesis of spinal accessory branches to the lower trapezius. There was a separate, although functionally minor, cervical plexus innervation of the lower trapezius.
Morphometry of intramuscular nerves in amyotrophic lateral sclerosis
Authors: Rosales Raymond L. , Osame Mitsuhiro , Madriaga Evelyn P. , Navarro Jose C. , Igata Akihiro
Published: January 2005

Morphometric analysis of 90 intramuscular nerves from the biopsied biceps muscles of 16 cases of amyotrophic lateral sclerosis (ALS) were done and compared with controls. In all fascicles (large and small) of ALS, the total number and the numbers of large and small myelinated fibers were significantly reduced to 52, 16, and 64% of controls, respectively. A histogram of the largest fascicles revealed a unimodal distribution and a shift to the left, showing a single peak at 1 μm diameter. The results indicate proximal and distal involvement of the most remote portions of the nerves to the muscle in ALS and support previous suggestions of a neuronopathy.
Myoadenylate deaminase deficiency: A clinical, genetic, and biochemical study in nine families
Authors: Sinkeler Sietze P. T. , Joosten M. G. , Wevers Ron A. , Oei T. Lian , Jacobs Alga E. M. , Veerkamp Jacques H. , Hamel Ben C. J.
Published: January 2005

The clinical significance of myoadenylate deaminase (MAD) deficiency and its mode of inheritance is still questioned. There were 36 relatives of 9 unrelated MAD deficient patients who were examined with the aid of a standardized ischemic forearm test: 8 new cases of MAD deficiency were detected, 5 of which were confirmed histochemically and biochemically. Obligate heterozygotes showed a normal ammonia production and MAD staining, but the mean activity of the enzyme was significantly less than in a group of controls. The results obtained from the family study strongly suggest an autosomal recessive mode of inheritance. However, only 2 of the 8 newly found MAD deficient individuals complained of exertional myalgia, whereas the remaining 6 were without any symptoms or complaints. The finding casts doubt on the clinical significance of MAD deficiency and the relationship of the deficiency state with exertional myalgia.
Neuromuscular disorders and thymoma
Authors: Witt N. J. , Bolton C. F.
Published: January 2005

We describe a patient who had asymmetrical atrophy of limb muscles and myasthenic weakness of neck, facial, and bulbar muscles. Electrophysiological tests indicated myasthenia gravis of facial muscles and changes consistent with an asymmetrical motor neuropathy as a cause of the muscle atrophy. Both conditions occurred as complications of a locally invasive thymoma, and both failed to improve after surgery and radiation but substantially improved with subsequent treatment by corticosteroids, azathioprine, and plasmapheresis. Review of the literature disclosed that several neuromuscular conditions may be associated with thymoma, the commonest being myasthenia gravis. Muscle atrophy may occur in 10% of patients who have myasthenia gravis, whether associated with or without thymoma. Its mechanism is debated, and further studies are needed, but observations in our patient suggest the atrophy is due to a motor neuropathy. Primary treatment of the thymoma by surgery, irradiation if the tumor is invasive, and immunosuppressive therapy for neuromuscular complications offers a relatively good prognosis for this group of patients.
Methods for estimating numbers of motor units in biceps‐brachialis muscles and losses of motor units with aging
Authors: Brown William F. , Strong Michael J. , Snow Robert
Published: January 2005

This paper presents a new method, here applied to the biceps‐brachialis muscles, for estimating motor unit numbers in healthy subjects. This method combines isometric contraction, intramuscular needle electrode recordings, and spike‐triggered averaging techniques to measure the sizes of motor unit potentials as recorded in the innervation zone with surface electrodes. The number of motor units is then estimated by division of the maximum biceps‐brachialis “M” potential recorded with the same surface electrodes and evoked by supramaximal stimulation of the musculocutaneous nerve, by the mean of at least 10 surface‐recorded motor unit potentials. The requisite intramuscular recordings provide additional information as to innervation density, incidence of linked potentials, and impulse blocking, phenomena that are particularly common in neurogenic and myogenic disoders. There was clear evidence of losses of motor units in older subjects: subjects over 60 years of age having approximately half the numbers of motor units of subjects under 60 years of age.
Regeneration of dystrophic muscle following multiple injections of bupivacaine
Authors: Martin Hunter , Ontell Marcia
Published: January 2005

Regenerated myofibers formed subsequent to orthotopic transplantation of young, dystrophic mouse muscle fail to display the extensive histopathological changes characteristics of murine dystrophy.3 In order to determine whether this modification of the phenotypic expression of murine dystrophy is unique to the transplantation system or whether it can be found when other extreme trauma induces dystrophic muscle to regenerate, the extensor digitorum longus muscles of 4–6‐week‐old normal (129 ReJ +/+) and dystrophic (129 ReJ dy/dy) mice were given two series of injections of the myctoxin bupivacaine, spaced 12 hours apart. These injections resulted in necrosis of ∼90% of the original myofibers. At 100 days after injection, the regenerated normal muscle appeared “healthy,” whereas the regenerated dystrophic muscle displayed histopathological changes. It is suggested that the differences in the time course of innervation of the myotubes in the transplantation system as compared with that in the bupivacaine system may be a factor in determining whether regenerated dystrophic myofibers express a dystrophic morphology.
Stability of lumbosacral somatosensory evoked potentials in a long‐term follow‐up
Authors: Berić Aleksandar
Published: January 2005

Variability of the lumbosacral somatosensory evoked potential (LSEP) in test/retest situations was assessed in 49 patients with nonprogressive neurological disorder and 20 healthy subjects. The average time of LSEP follow‐up in the patients was 16.2 months. The first group of healthy subjects had a short test/retest period of between 2 days and 2 weeks, and the second group had a long period between tests, with a mean of 35.7 months. The R and S waves of the LSEP were analyzed separately for latency and amplitude. Test/retest differences were statistically compared. The average correlation coefficient for healthy subjects was 0.84 and for patients was 0.78. These results suggested a remarkable stability of LSEPs in both healthy subjects and patients with nonprogressive neurological disorders. Therefore, we propose that LSEPs can be used in follow‐up both to screen for initial dysfunction of the sensory system and to detect any changes in present dysfunction.
Effect of desynchronized inputs on compound sensory and muscle action potentials
Authors: Kimura Jun , Sakimura Yoko , Machida Masafumi , Fuchigami Yasunori , Ishida Tetsuro , Claus Detlef , Kameyama Shigeki , Nakazumi Yuji , Wang Jin , Yamada Thoru
Published: January 2005

Stimulation of the second (S1) or third (S2) digit elicits a median sensory potential at the wrist. Similarly, a shock applied to the median (Sm) or ulnar (Su) nerve at the wrist evokes a sensory potential of the fourth digit and a muscle potential over the thenar eminence. Hence, a concomitant application of S1 and S2 or Sm and Su with varying interstimulus intervals simulates the effect of desynchronized inputs. In 10 hands, a shift in latency on the order of 1 msec between S1 and S2 or Sm and Su caused a major reduction in sensory potential by as much as 30–40% but little change in muscle action potential. A latency difference slightly less than one‐half the total duration of unit discharge maximized the phase cancellation between the two components and consequently the loss of area under the wave‐form.
Comparison of force and stiffness in normal and dystrophic mouse muscles
Authors: Gordon T. , Stein R. B.
Published: January 2005

Isometric force and stiffness of fast‐ and slow‐twitch muscles of affected and normal mice of the 129/ReJ dy/dy strain were studied at rest and during active contraction at a variety of lengths. Dystrophic muscles developed less force in response to stimulation, but the resting stiffness was not reduced as much, particularly at long muscle lengths. This is consistent with the replacement of muscle fibers by connective tissue that is considerably less elastic. When second and third stimuli are superimposed on the rising phase of a twitch in a normal muscle, a less‐than‐linear summation of force and stiffness generation (early depression) is followed by a more‐than‐linear summation (later facilitation). Dystrophic muscles showed a smaller early depression and a greater later facilitation of force and active muscle stiffness. Many of these phenomena can be predicted from a simple model of Ca2+ release and binding to troponin.
Immunocytochemical localization of α‐actinin in frog muscle treated with the ionophore A23187
Authors: Llados Fernando T. , Kriho Virginia , Pappas George D.
Published: January 2005

Incubation of frog skeletal muscle with the ionophore A23187 induces severe damage in the muscle. At the level of the Z line, the ionophore induces redistribution and release of the protein α‐actinin, as shown by immunocytochemical techniques. The ionophore does not induce damage in denervated preparations or in preparations pretreated with d‐tubocurarine, which indicates that the effect is indirect and neurally mediated. It is concluded that the increase in spontaneous transmitter release produced by the ionophore induces Ca2+ influx through the acetylcholine receptor. Calcium ions activate neutral proteases which release α‐actinin from the Z line.
AAEE minimonograph #31: The electrodiagnosis of ulnar neuropathy at the elbow
Authors: Kincaid John C.
Published: January 2005

Suspected ulnar neuropathy at the elbow is commonly evaluated in the electromyography lab. In this report the anatomy and pathology of ulnar elbow lesions are reviewed. The patterns of electrophysiologic abnormality that have been reported in the literature and in the author's own laboratory are discussed along with a suggested routine for evaluation.
Isomyosin changes after functional electrostimulation of denervated sheep muscle
Authors: Carraro Ugo , Catani Claudia , Saggin Leopoldo , Zrunek Michael , Szabolcs Mathias , Gruber Helmut , Streinzer Wilhelm , Mayr Winfried , Thoma Herwig
Published: January 2005

Isomyosin analyses by biochemical, immunochemical, and histochemical investigations have been carried out in five sheep following unilateral recurrent laryngeal nerve paralysis and direct functional electrostimulation of the denervated cricoarytenoid posterior muscle. Myosin light chains were identified by two‐dimensional gel electrophoresis. Myosin heavy chains were analyzed by one‐dimensional SDS‐polyacrylamide gel electrophoresis. Slow myosin heavy chain was identified by orthogonal peptide mapping and immunochemistry. The stimulation effect at cellular level was determined using adenosine triphosphatase (ATPase) histochemistry. A dramatic increase of the type 1 fiber area (slow, fatigue‐resistant fibers) could be seen after many weeks of an increasing regime of low‐frequency direct electrical stimulation. Biochemically, the amout of slow myosin was always higher than in normal muscles. Some muscles were transformed almost completely to the slow type. At the time they were studied and with the methods employed, the expression of embryonic isomyosin was not observed. In conclusion, after numerous weeks of maintained functional activity, elicited by direct electrostimulation, the denervated muscle regionally showed areas of hypertrophy or at least lack of atrophy of slow myofibers without major signs of muscle damage.
The distribution of slow myosin in rat muscles after neonatal nerve crush
Authors: Lowrie Margaret B. , Dhoot Gurtej K. , Vrbova Gerta
Published: January 2005

Following neonatal nerve injury fast skeletal muscles recover less well than slow ones. This is because many muscle fibers are lost during reinnervation. Since fast muscles normally contain a small population of slow muscle fibers, we have used a monoclonal antibody to slow myosin heavy chains (SMHC) to study their number and pattern of distribution in fast muscles following temporary denervation at 5–6 days of age and subsequent reinnervation. During this time the original distribution of slow fibers changed to one showing irregular grouping, indicating that reinnervation of muscles after neonatal nerve injury is as nonselective as it is after nerve injury in adults. Despite a large reduction in the total number of muscle fibers during reinnervation, the number of slow fibers did not decrease. Thus muscle fiber loss was at the expense of the fast motor units alone.
The human cervical myotomes: An antatomical correlation between electromyography and CT/myelography
Authors: Katirji M. Bashar , Agrawal Rakesh , Kantra Trudy A.
Published: January 2005

To correlate the accuracy of electromyography in diagnosing the correct root involved in cervical radiculopathy, 20 patients with cervical radiculopathy, diagnosed by electromyography using strict inclusion and exclusion criteria, were studied. Metrizamide myelography/computerized tomography were evaluated in all 20 patients independently, and the involved root was defined. The root involved, using the EMG examination and the myotome chart of the Medical Research Council, was C5 in 3 patients, C6 in 6, C7 in 9 patients, and C8 in 2 patients. The overall correlation with myelography/CT was 65% (33.3, 66.6, 77.7, and 50% for C5, C6, C7, and C8, respectively). EMG done properly has a good correlation of myelography/CT. This correlation is higher (73.3%) for the commonly occurring cervical radiculopathies (C6 and C7).
X‐linked dominant charcot–marie–tooth neuropathy with 15 cases in a family genetic linkage study
Authors: Ionasescu Victor V. , Burns Trudy L. , Searby Charles , Ionasescu Rebecca
Published: January 2005

A large CMT family with 5 affected males and 10 affected females of 37 members in four generations was investigated by recombinant DNA studies. The proband patient in his original desscription of the pedigree indicated male‐to‐ male transmission in one of his relatives, suggesting autosomal dominant inheritance. The genetic linkage study between the CMT locus and the loci of six markers mapped on chromosome 1 (FY, APCS, AT3, REN, APOA2, and GBA) gave negative results. These findings prompted further pedigree investigation which proved that male‐to‐male transmission was not present. A genetic linkage study with DXYS1, which is a DNA marker mapped on the long arm of the chromosome X, revealed tight linkage with ẑ = 3.15 at θ = 0.10.
Clinical investigation in Duchenne muscular dystrophy: Penicillamine and vitamin E
Authors: Fenichel Gerald M. , Brooke Michael H. , Griggs Robert C. , Mendell Jerry R. , Miller J. Phillip , Moxley Richard T. , Park Jane H. , Provine Michael A. , Florence Julaine , Kaiser Kenneth K. , King Wendy M. , Pandya Shree , Robison Jenny , Signore Linda
Published: January 2005

A double‐blind controlled trial of penicillamine and vitamin E against placebo was conducted in 106 boys with Duchenne muscular dystrophy. Nine dropped out of the study after being randomized. Patients were evaluated using an established protocol that measures muscle strength, joint contractures, functional grade, and pulmonary function. The trial lasted for 18 months. The power of the study to detect a 75% slowing of the disease was 0.95 at a P < 0.05. No therapeutic effect was observed in the patients taking penicillamine and vitamin E as compared with those taking placebo.
Structural and functional analysis of murine skeletal muscle after castration
Authors: Bmed Bian Jiang , Klueber Kathleen M.
Published: January 2005

A previous histochemical and morphometic study demonstrated that castration caused a significant decrease in myofiber and muscle size in the extensor digitorum longus (EDL) muscles of male ReJ 129 mice. The objective of the present study was to examine the effects of castration on the morphology and physiology of the EDL. Muscle wet weight was significantly decreased in the castrated group. The morphological survey demonstrated a significant degree of degeneration in the EDL muscles from castrated animals, consisting of disruption of normal myofilament arrangement and necrosis, invasion of active macrophages, and atrophic myofibers. These findings were significantly correlated with the decrease in peak tension observed in the castrated groups. No significant difference was detected in the time to peak tension and half‐relaxation time in the castrated groups compared with the control. Thus, alterations of the morphological integrity and myofiber size of skeletal muscle affect muscle strength in castrated animals.
Hereditary increased muscle mechanical irritability and progressive contracture with stretch‐induced electromyog‐raphic activity
Authors: Jušić Anica
Published: January 2005

A son and mother are reported with autosomal dominantly transmitted painless, increased mechanical irritability in the limb and trunk muscles and progressive finger contracture. Immediately after a tap, muscle swelling appeared. With light tapping, wavelike muscle surface movements appeared. Progressive contractures developed first in the proximal interphalangeal finger joints and subsequently involving the lower arm muscles. The contractures disappeared in the local curare test. No spontaneous activity was recorded on concentric needle recording. Serial repetitive activity was recorded with fine wire electrode recording, induced by muscle stretch, performed by percussion hammer blows or by prolonged finger grasp. A slight, irritative peripheral nervous lesion could be the cause. The chronic sensorimotor polyneuropathy may be also a part of the syndrome.
Evaluation of an automatic method of measuring features of motor unit action potentials
Authors: Stewart Charles R. , Nandedkar Sanjeev D. , Massey Janice M. , Gilchrist James M. , Barkhaus Paul E. , Sanders Donald B.
Published: January 2005

This study was performed to evaluate an automatic method of motor unit action potential (MUAP) analysis developed in our laboratory. MUAPs were recorded from the biceps brachii muscle of 68 normal subjects and 122 patients with nerve or muscle disease. The values of mean MUAP durations from normal subjects obtained by automatic analysis were similar to those reported in the literature. However, the normal range of MUAP amplitude and the incidence of polyphasic MUAPs were much higher. Normal ranges of mean MUAP area, area/amplitude ratio, and the number of turns were also defined. Automatic analysis demonstrated an abnormality of at least one MUAP feature in 70% of patients. There was concordance between automated analysis and visual assessment of MUAPs in 76% of patients with neuropathy but in only 50% of patients with myopathy. The relationships between different MUAP features seen in neuropathy and myopathy are explained in physiologic terms.
Mechanisms that produce rapid damage to myofilaments of amphibian skeletal muscle
Authors: Duncan Christopher J.
Published: January 2005

The system causing myofilament damage is separate from the phospholipase A2 pathway, Ca activation of which ultimately causes sarcolemma breakdown in muscle cells. Mitochondrial agents cause myofilament damage in saponin‐skinned frog pectoris cutaneous muscle when [Ca] = 0. There are parallels with other systems that generate oxygen radicals. However, a variety of protectors against oxygen radicals, or anoxia, failed to protect; Ca‐activated damage was not augmented by diethylthicarbamate, nor was it accompanied by a respiratory burst. Thus, there is no firm evidence implicating oxygen radicals in myofilament damage. Thiol‐oxidizing agents cause contraction damage in skinned muscle that resembles the quasirigor induced in myosin by N‐ethylmaleimide. Activation of transmembrane dehydrogenases and electron flow produced damage and increased Ca sensitivity in skinned muscle, and it is suggested that this enzyme system may be implicated in characteristic damage to the myofilaments via redox cycling and modification of sulphydryl groups; its possible location on the sarcoplasmic reticulum is discussed.
Scanning electron microscopy of teased intrafusal muscle fibers from rat muscle spindles
Authors: Schröder J. Michael , Bodden Herbert , Hamacher Alfred , Verres Christoph
Published: January 2005

Scanning electron microscopic (SEM) studies on intrafusal muscle fibers and their various sensory and motor endings are not available thus far although SEM greatly increases the resolution power for analyzing surface structures in comparison to light microscopic preparations. From a total of 68 isolated muscle spindles in lumbrical muscles of Wistar rats, only one primary sensory ending could be isolated. Secondary sensory endings were of an annulospiral, a flat, cuff‐shaped, or a more complicated branched type; they were always completely surrounding intrafusal muscle fibers. Motor terminals were more focally arranged not surrounding the muscle fibers. Three types could be distinguished. Collagen fibrils were seen to insect on capsular elements as well as on the surface of intrafusal muscle fibers. Thus SEM helps understanding the most complicated electromechanical system for motor control.
Spontaneous diabetes mellitus in a rhesus monkey: Neurophysiological studies
Authors: Cornblath David R. , Dellon A. Lee , MacKinnon Susan E.
Published: January 2005

Peripheral neuropathy is a common complication of human diabetes, but its occurrence in spontaneously diabetic monkeys is unknown. Four months after developing diabetes, a 22‐year‐old female rhesus monkey had nerve conduction studies which were compared with control data obtained from 9 nondiabetic rhesus monkeys. In the diabetic monkey, median and ulnar sensory action potential amplitudes and the median motor distal latency differed from controls by more than two standard deviations. Conduction velocities in the diabetic monkey were less than the mean values in controls, although none were beyond two standard deviations of control means. These electrophysiologic abnormalities are similar to those described in human diabetes and suggest that the spontaneously diabetic monkey peripheral nervous system may be a suitable model of experimental diabetic neuropathy.
Proteins of muscle subcellular fractions in Duchenne progressive muscular dystrophy stained with “Stains‐all” cationic carbocyanine dye and with Coomassie blue
Authors: Niebroj‐Dobosz I. , Kornguth S. , Schutta H. , Siegel F. L. , Hausmanowa‐Petrusewicz I.
Published: January 2005

The protein compositions of subcellular fractions of muscle obtained from 17 Duchenne dystrophy patients, 15 disease controls (10 different primary myopathies, 5 spinal muscular atrophy patients), and 10 normals were examined by polyacrylamide gel electrophoresis. The gels were stained with Coomassie Brilliant Blue and with “Stains‐all,” which stains calcium‐binding proteins, sialic acid‐rich glycoproteins, and phosphoproteins. In muscle membrane fractions of Duchenne dystrophy patients there was a marked reduction in the concentrations of calsequestrin and a 39 kDa protein that stained blue with “Stains‐all.” There were changes in the proteins of all sub‐cellular fractions of Duchenne's patients; some of these changes appear to be specific for Duchenne dystrophy (DD). There was no apparent correlation between the protein changes observed on acrylamide gels and the age of the patients, the duration of the disease, the degree of disability, or activity of creatine kinase. A decreased level of calsequestrin in DD sarcoplasmic reticulum may contribute to an increased level of free calcium seen in muscle from these patients.
Muscle glycerol kinase in Duchenne dystrophy and glycerol kinase deficiency
Authors: Seltzer William K. , Angelini Corrado , Dhariwal Gulshan , Ringel Steven P. , McCabe Edward R. B.
Published: January 2005

The complex glycerol kinase deficiency (GKD) syndrome is an X‐linked recessive genetic disorder. The syndrome often includes a myopathy that is similar histologically to Duchenne muscular dystrophy (DMD). The glycerol kinase (GK) locus is in the Xp21 region in the midportion of the short arm of the X chromosome and is in close proximity to the DMD locus. We have investigated GK activity and subcellular distribution of muscle GK in DMD patients and in a patient with the complex GKD syndrome presenting with myopathy. We found no abnormality of muscle GK specific activity or sub‐cellular distribution in DMD. In the patient with the complex GKD syndrome the specific activity and kinetics of muscle GK were normal, but the subcellular distribution of muscle GK was altered. Liver GK had less than 10% of normal activity and showed markedly altered kinetics. These findings indicate that there is no abnormality of muscle GK activity in DMD muscle. Furthermore, the normal GK activity in an individual with the complex GKD syndrome suggests that muscle and liver GK are genetically distinct. These findings support the concept that the complex GKD syndrome results from small deletions that affect closely linked but separate loci for DMD, GK and adrenal hypoplasia.
The single‐fiber EMG in chronic demyelinating neuropathy
Authors: Oh Shin J.
Published: January 2005

Various parameters of single‐ fiber electromyography (SFEMG) were studied in 19 patients with electrophysiologically and histologically proven chronic demyelinating neuropathy. The mean duration of disease at the time of testing was four years.

Motor nerve conduction in the median nerve was abnormal in all patients, whereas sensory nerve conduction was abnormal in all but one. Needle EMG in the extensor digitorum communis (EDC) muscle showed rare fibrillations and fasciculations and some abnormal motor unit potentials in most of patients. SFEMG in the EDC muscle showed an increased fiber density in seven cases (37%) and minimally abnormal jitter in 14 cases (74%). Single‐fiber action potentials were stable, whereas blocking was rare. Fiber density was significantly increased in patients with fibrillation in the conventional needle EMG.

Our study showed that the SFEMG is mildly abnormal in many patients with demyelinating neuropathy and that this test is useful in detecting and quantitating axonal degeneration in demyelinating neuropathy.
31P‐NMR spectroscopy: The metabolic profile of malignant hyperpyrexic porcine skeletal muscle
Authors: Foster Paul S. , Hopkinson Kenneth , Denborough Michael
Published: January 2005

31Phosphorus‐NMR spectroscopy may have the potential to help in the noninvasive diagnosis of malignant hyperpyrexia (MH). Changes in the phosphate‐metabolite profile of MH‐susceptible (MHS) skeletal muscle occur more readily under conditions of anoxia than in control muscle. Induction of anoxia caused a rapid fall in intracellular phosphocreatine, an elevation of inorganic phosphate, and finally a diminution of ATP in MHS muscle. The onset of metabolic change was slower in control tissue. Increased oxygen consumption may occur in anoxic MHS muscle, which leads to accelerated glycolysis and a rapid fall in the intracellular high‐energy phosphates. In MHS muscle an abnormality may exist in carbohydrate metabolism linked with poor resynthesis of the high‐energy phosphates, which may be precipitated under anaerobic conditions. Accelerated muscle metabolism is also observed in the presence of 2 mM caffeine and 3% halothane in MHS muscle. Changes in the concentrations of metabolites could be mapped noninvasively under anoxic conditions using topical 31P‐NMR.