bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sural nerve conduction study in the rat: A new technique for studying experimental neuropathies
Authors: DeJesus C. P. V. , Towfighi J. , Snyder D. R. 
Published: January 2005

AbstractAn electrophysiologic technique for studying sensory fibers in the rat sural nerve is described. The conduction velocity of the sural nerve in rats is much slower than in humans, probably because of the lack of large myelinated nerve fibers in rats. An experimental neuropathy (induced by hexachlorophene) that predominantly causes a myelin disorder produced a slowing of sural nerve conduction velocity and a potential of normal amplitude and duration. An experimental neuropathy (induced by zinc pyrithione) that primarily causes axonal degeneration produced a sensory potential of lower amplitude and shorter duration that had a normal conduction velocity.
Myasthenia gravis: Review of diagnosis and management
Authors: Patten Bernard M. 
Published: January 2005

AbstractAlthough the cause of myasthenia gravis is still unknown, its pathogenesis appears clear: immunologic attack on synaptic receptors in muscle causes receptor deficiency, decreased miniature endplate potentials, and decrements in the compound action potentials evoked from muscles on repetitive stimulation of peripheral nerves. In addition to the involvement of skeletal muscle, some MG patients may manifest subtle alterations of the function of heart, lung, smooth muscle, and CNS, indicating that this is truly a systemic disorder. Modern therapy involves adjusting treatment to the needs of individual patients. Anticholinesterases, calcium, ephedrine, potassium, and germine partially correct the defect in neuromuscular transmission; prednisone, ACTH, cytotoxic drugs, antilymphocyte serums, gamma globulin, thoracic duct drainage, plasmapheresis, and thymectomy partially modify the abnormalities of the immune system.
Isometric tension from rotary stimulation of fast and slow cat muscles
Authors: Lind Alexander R. , Scott Petrofsky Jerrold 
Published: January 2005

AbstractIn cats anesthetized with α‐chloralose, different populations of motor units in soleus, plantaris, and medial gastrocnemius muscles were stimulated in rotation through surgically divided groups of ventral roots. As a result, smooth muscular contractions were obtained at low frequencies of rotary stimulation, and maximal tetanic tensions were induced at frequencies within the upper range of voluntary contractions. The frequencies necessary to induce maximal tetanic contractions were lower for slow‐twitch muscles than for fast‐twitch muscles. It is speculated that the primary benefit resulting from asynchronous stimulation of the muscles is in the engagement of the tendon, which permits motor units to exert their tension without having to overcome a major portion of the elastic damping.
Actin‐containing microprocesses in the fusion of cultured chick myoblasts
Authors: Huang Helena L. , Singer Robert H. , Lazarides Elias 
Published: January 2005

AbstractScanning electron microscopic studies of myoblasts from 11‐to 13‐day‐old chick embryonic breast muscle cultred on collagen‐coated glass coverslips showed six stages of development into multinucleated myotubes: (1) growth of flattened, spread‐out cells for 20–30 hr following initiation of monolayer cultures; (2) extension of microprocesses (1–150 μm) from cells that have become spindle shaped; (3) contact and adherence of microprocesses from adjacent cells; (4) thickening of fused processes; (5) approximation of the cells; and (6) coalescence of the cells to form a spindle‐shaped myotube. When the calcium‐ion concentration in the growth medium was lowered‐either by increasing the concentration of ethylene‐glycol‐bis (aminoethyl ether) N, N'‐tetraacetate (EGTA) or by decresing the concentration of free calcium ion used‐the number of microprocesses present on the cells was reduced. Presumably, however, these microprocesses could still fuse together, provided that the calciumion concentration was greater than 160 μM. Indirect immunofluorescence assay with actin‐specific antibody indicated that actin is a major component of the myoblasts' microprocesses. Cytochalasin B (5μg/ml) caused the microprocesses to retract within 15 min and the myoblasts to round up and detach from the glass substrate. This was presumably caused by the action of the drug on actin filaments.
The entrapment neuropathies
Authors: Nakano Kenneth K. 
Published: January 2005

AbstractThis article discusses various entrapment neuropathies as well as their clinical features and treatment. In most patients with compression neuropathies, diagnosis and therapy can be effected early if a careful neurologic examination as well as x‐ray and electrodiagnostic (EMG and nerve conduction) studies are performed when the patient initially presents with symptoms.
Late‐onset X‐linked recessive spinal and bulbar muscular atrophy
Authors: Ringel Steven P. , Lava Neil S. , Treihaft Marc M. , Lubs Mary L. , Lubs Herbert A. 
Published: January 2005

AbstractA family is described in which five males have late‐onset facial weakness, dysarthria, dysphagia, and slowly progressive proximal weakness. Electrodiagnostic studies and muscle biopsy were compatible with spinal muscular atrophy. This family appears quite similar to several previously reported families with late‐onset X‐linked recessive spinal and bulbar muscular atrophy. Because of the relative homogeneity of this particular phenotype of spinal muscular atrophy, a single metabolic derangement was sought. Three obligate carriers were studied, and no abnormality was detected. A further family with this condition is briefly discussed.
On the occurrence of striated muscle within the spinal leptomeninges
Authors: Lipow Kenneth , Horoupian Dikran S. , Raine Cedric S. 
Published: January 2005

AbstractA clinically normal adult male rabbit was found to possess fascicles of muscle fibers within the leptomeninges over the spinal cord at L6, L7, and S1. The finding is believed to be purely incidental and unrelated to any experimental procedure. Morphologically, the fascicles had the characteristics of striated muscle; and, while most were of normal dimensions, several were made up of small fibers 4–10 μm in diameter. Motor endplates, capillaries, and endomysial and perimysial connective tissue were also present. Axons myelinated by Schwann cells were associated with the normal bundles but were absent from the bundles of small fibers. In such bundles, large, unmyelinated axons predominated, some of which lacked ensheathment while others were invested by perineurial‐type cells. The observation of incidental intraleptomeningeal skeletal muscle probably reflects a rare developmental anomaly. Its occurrence in humans is also discussed.
Neurophysiological investigation of subclinical and minimal toxic neuropathies
Authors: Le Quesne Pamela M. 
Published: January 2005

AbstractIn the investigation of subclinical or minimal toxic neuropathies, selection of the proper electrophysiological test depends largely on the nature of the condition being studied. Examples are given of several toxic disorders, and their features are discussed in relation to the appropriate electrophysiological measurement.
Electromyographic assessment of central motor disorders
Authors: Wiesendanger Mario , Rüegg Dieter G. 
Published: January 2005

AbstractExperimental procedures are described that were designed to assess central motor disorders quantitatively. Initially delineated is a study of triggered ballistic movement performed in a reaction‐time situation. The reciprocal triphasic EMG pattern recorded in an antagonistic muscle pair was clearly abnormal in Parkinsonian patients; increased duration, diminished synchronization of motor units, and a tendency for coactivation of agonist and antagonist muscles and for action tremor were observed. Transport time of elbow movement was prolonged, particularly in a choice reaction‐time situation. Rapid, passive displacements of the forearm combined with excitability measurements of hindlimb motoneurons in monkeys revealed the existence of a transcortical loop that may contribute to increased muscle tone in Parkinsonian patients.
Early changes in chlorphentermine myopathy of rat studied by freeze fracturing
Authors: Schmalbruch Henning 
Published: January 2005

AbstractChlorphentermine interferes with the metabolism of phospholipids. When administered to the rat in daily doses for 5 days, it causes necrosis of muscle fibers that are rich in mitochondria. Before the onset of necrosis, the following characteristics of freeze‐fractured muscle preparations were observed: multilayered lipid globules and single‐layered lipid membranes without membrane particles; different stages of exocytosis of lipid through the plasma membrane of the muscle fibers; and areas of plasma membrane that were devoid of particles of intramembranous proteins. These latter areas may arise secondary to exocytosis, to fusion of lipid vesicles with the plasma membrane, or to a direct action of chlorphentermine on the membrane. It is not known whether these areas give rise to membrane defects and fiber necrosis.
HLA, anti‐DNA, and complement in myasthenia gravis
Authors: Christiansen Frank T. , Houliston John B. , Dawkins Roger L. 
Published: January 2005

AbstractTwenty‐seven patients (18 females and 9 males) with myasthenia gravis were HLA‐A, ‐B, ‐C, and ‐D typed, and the results were analyzed with relation to evidence of immunodeficiency, thymic disease, and associated autoimmune processes. An association of A1, B8, and DRW3 appeared to identify a group of 8 females with higher mean anti‐DNA, lower mean C4, and lower mean E. coli antibody titer than other females in whom CW4 (with or without BW35) was common (6 of the remaining 10 females were in this category). Antiacetylcholine receptor (anti‐AChR) autoantibody and reduced serum lgM and isohemagglutinin titers were not clearly related to particular HLA specificities. These results suggest that HLA‐A1, ‐B8, ‐DRW3, and ‐CW4 may be related to associated phenomena rather than playing a major role in the development of anti‐AChR and myasthenia gravis.
Hypoxanthine‐guanine phosphoribosyltransferase activity of blood and muscle in duchenne dystrophy
Authors: Neerunjun Joseph S. , Allsop Jennifer , Dubowitz Victor 
Published: January 2005

AbstractHypoxanthine‐guanine phosphoribosyltransferase (HGPRT) activity was measured in red cells and in skeletal muscles of normal and Duchenne subjects. [8‐14C] hypoxanthine was used as substrate, and 5‐phospho‐α‐D‐ribose 1‐diphosphate (PRPP) was used as the ribose‐5‐phosphate donor. The [8‐14C] inosine monophosphate (IMP) formed was separated by high‐voltage electrophoresis, and radioactivity was measured by liquid scintillation counting. HGPRT activity in Duchenne and normal red‐cell hemolysates was similar, but such activity was significantly higher in Duchenne than in normal muscle homogenates. Red cells of both normal and Duchenne subjects had significantly higher enzyme activity than did skeletal muscles. It is suggested that increased HGPRT activity may be involved in enhancing protein synthesis by increasing intracellular levels of purine ribonucleotides.
Neurotrophic control of skeletal muscle phospholipids
Authors: Fernandez Hugo L. , Dorman Robert V. , Festoff Barry W. 
Published: January 2005

AbstractThe phospholipid composition of rat gastrocnemius muscles was assessed one to nine days after sciatic nerve transection was performed either close to the muscle (5–8 mm from the point of entrance of the nerve into the muscle for short‐stump nerve sections) or far from it (30–35 mm central to the nerve's point of entrance for long‐stump nerve sections). In both instances, denervation did not cause striking changes in total phospholipid content but resulted in a selective loss of 1,2‐diacyl‐sn‐glycero‐3‐phosphorylethanolamine (phosphatidyl ethanolamine, GPE). The quantity of GPE in denervated muscles was found to be significantly less than that in controls (p<0.01) within one day for short‐stump preparations, as compared to three days for long‐stump preparations. Also, direct comparison of short‐ and long‐stump GPE values showed significant differences (p<0.01) at all times from the first to the fifth day following denervation, with no difference detected thereafter. These results imply that maintenance of skeletal muscle GPE involves a neurogenic influence which is independent of nerve‐evoked muscle activity. This conclusion may help us understand neuromuscular diseases in which perturbation of phospholipid components has been implicated.
Amplitude of the surface electromyogram during fatiguing isometric contractions
Authors: Lind Alexander R. , Petrofsky Jerrold S. 
Published: January 2005

AbstractFive volunteer subjects held isometric handgrip contractions at specific submaximal tensions until the required tension could no longer be maintained. At the start of those contractions, the amplitude of the surface electromyogram (EMG) was linearly related to the tension exerted; the amplitude of the EMG increased linearly throughout these sustained contractions by a constant amount—about 30% of the maximum. During sustained contractions, brief, intermittent maximal efforts showed that strength declined linearly at all tensions. At 25% maximal voluntary contraction (MVC), there was a linear fall in the EMG amplitude associated with the brief maximal efforts, but the fall in strength was more rapid than the fall in EMG amplitude. At 70% MVC, there was no fall in the EMG amplitude in response to the brief maximal efforts, while the muscle strength fell linearly.
Cylindrical spirals in human skeletal muscle
Authors: Carpenter Stirling , Karpati George , Robitaille Yves , Melmed Calvin 
Published: January 2005

AbstractMuscle biopsies from two patients revealed that numerous type 2 fibers contained large abnormal areas filled with cylindrical spirals. The cytochemical profile of these cylindrical spirals was sufficiently characteristic that they could be distinguished from tubular aggregates. Their electron microscopic appearance was unmistakable. Their origin and significance are uncertain. The diverse nature of the patients' conditions (cramps and malignancy, and an unusual form of spinocerebellar degeneration) indicate that these abnormal structures are not disease specific.
Reinnervation of rat extensor digitorum longus muscles after free grafting
Authors: Carlson Bruce M. , Wagner Kenneth R. , Max Stephen R. 
Published: January 2005

AbstractFree grafts of the extensor digitorum longus (EDL) muscle of the rat are invaded by regenerating nerve fibers during the second postoperative week. Neuromuscular junctions are established during the third week. Levels of choline acetyltransferase (CAT) activity parallel the invasion of the graft by nerve fibers, but this activity never returns to control levels. We conclude that incomplete reinnervation of free muscle grafts may be a factor in the failure of such grafts to reattain the mass of control muscles.
New muscle transplant method produces normal twitch tension in dystrophic muscle
Authors: Law Peter K. , Yap John L. 
Published: January 2005

AbstractGrafting newborn muscle is an innovative method of muscle transplant. This method overcomes hypoxia in the deeper fibers and facilitates reinnervation and revascularization of the grafted muscle fibers, thus promoting the survival and development of the characteristics of the donor muscle. The result achieved is superior to that obtained from mature muscle grafts or from minced muscle transplants. When an intact soleus from a 1‐day‐old normal mouse was grafted into a recipient soleus of a 20‐day‐old dystrophic C57BL/6J‐dy2J mouse, the actively developing normal graft helped to improve the structure and function of the dystrophic muscle. When compared to the intact dystrophic solei, the test dystrophic muscles five to six months after operation showed increases in cross‐sectional area, in wet weight, in twitch and tetanic tension, and in the number of muscle fibers with high resting membrane potentials. This is the first procedure to have raised the muscle twitch tension in an adult dystrophic mouse to the normal level.
Treatment of denervated muscle by gangliosides
Authors: Caccia M. R. , Meola G. , Cerri C. , Frattola L. , Scarlato G. , Aporti F. 
Published: January 2005

AbstractShort‐duration cooling of the nerve to the extensor digitorum longus muscle of the rat in vivo induced partially reversible denervation of the muscle and atrophy in the type 2 muscle fibers. Increases in cyclic adenosine monophosphate, cyclic guanosine monophosphate phosphodiesterase, adenylate cyclase, and guanlate cyclase were observed in the denervated muscle. Treatment with gangliosides of the bovine brain cortex seemed to improve the excitability of the surviving motor units and to encourage recovery of neuromuscular trophic control, but it did not affect the nerve conduction velocity or the contractile properties of the denervated muscle.
Trichinosis: Clinical report and histochemistry of muscle
Authors: Gross Brian , Ochoa José 
Published: January 2005

AbstractA 35‐year‐old woman contracted severe trichinosis which was atypical in that it lacked a gastrointestinal prodrome and periorbital edema, and in that eosinophilia developed only late in the course of the illness. The patient developed an incapacitating myositis as well as complications of encephalopathy, myocarditis, and retinal hemorrhages, resulting in severe debilitation of more than two and one‐half months' duration. Muscle histochemistry illustrated previously unreported features.
The afferent influence on the voluntary firing range of individual motor units in man
Authors: Hannerz Jan , Grimby Lennart 
Published: January 2005

AbstractThe firing ranges of 50 normal anterior tibial or short toe extensor motor units in sustained isometric voluntary contraction were studied in electromyographic recordings. The afferent inflow was decreased by compression of the sciatic nerve, thereby blocking large afferents before alpha efferents. Motor units with low minimum and low maximum rates before blockade had higher minimum and maximum rates on blockade. Some motor units with high minimum and maximum rates before blockade had a lower minimum but an unchanged maximum rate on blockade. The firing range recorded for both types of motor unit on blockade was also recorded for all tonically firing motor units during early reinnervation after traumatic lesion to the muscle nerve in 14 patients. It is concluded that both facilitating and inhibiting proprioceptive afferent activity is involved in the differentiation of motor unit firing ranges in sustained isometric voluntary contraction.
A new regional curare test of the elbow flexors in myasthenia gravis
Authors: Horowitz Steven H. , Krarup Christian 
Published: January 2005

AbstractElectrical and mechanical responses of the elbow flexors (EFs) and the adductor pollicis muscle (ADP) were evoked in 31 patients with myasthenia gravis (MG). Thirteen patients with moderate or severe involvement showed a decrement during trains of repetitive stimuli in both muscle types, greater in the proximal ones than in the distal one. Seven of 18 patients with mild generalized or ocular MG showed abnormalities in the EFs, and 4 patients showed abnormalities in the ADP. A regional curare test was performed in the EFs of 11 patients with borderline or no abnormalities in the EFs and the ADP. All patients were more sensitive to curare than were control subjects; in 2, a decrement outside the range of controls could only be provoked in the partly curarized muscle during posttetanic exhaustion. Excitation‐contraction coupling, as evidenced by the staircase phenomenon and after correction for blockade of fibers, was abnormal in 5 of 31 patients in the EFs, and in 11 patients in the ADP. In both muscles, the action potential was a more sensitive criterion of abnormality than the mechanical response. The decrement in the action potentials during 3/sec stimuli gave the largest diagnostic yield.
Role of plasma membrane defect of skeletal muscle in malignant hyperthermia
Authors: Gallant Esther M. , Godt Robert E. , Gronert Gerald A. 
Published: January 2005

AbstractHalothane, at clinical concentrations, depolarizes the plasma membrane of skeletal muscle from Poland China pigs susceptible to malignant hyperthermia but does not affect the resting membrane potential of muscle from normal Poland China pigs, mice, or frogs. The depolarization is reduced or partially reversed in the presence of dantrolene sodium. We suggest the possibility that malignant hyperthermia may be initiated by this abnormal depolarization of skeletal muscle by halothane.
Recovery from central core degeneration of the tenotomized rat soleus muscle
Authors: Baker James H. , Hall‐Craggs E. C. B. 
Published: January 2005

AbstractThe soleus muscle of the rat undergoes degenerative changes after tenotomy. The effects are maximal one week postoperatively, after which follows a period of recovery. Muscle histology eventually returns to normal six weeks after tenotomy. Recovery is effected by means of peripheral myofibril splitting and de novo synthesis of myofibrils within the central portion of the fiber.
Neuralgic amyotrophy manifesting as anterior interosseous nerve palsy
Authors: Rennels Glenn D. , Ochoa José 
Published: January 2005

AbstractNeuralgic amyotrophy may present as a picture of anterior interosseous nerve palsy. In such a case, rather than a lesion of the nerve in the forearm, we offer indirect evidence of a lesion in the brachial plexus affecting discrete fiber bundles destined to form the anterior interosseous nerve.
Autosomal recessive generalized myotonia
Authors: Zellweger H. , Pavone L. , Biondi A. , Cimino V. , Gullotta F. , Hart M. , Ionasescu V. , Mollica F. , Schieken R. 
Published: January 2005

AbstractFour cases of autosomal recessive generalized myotonia are reported. Attention is drawn to the fact that this condition represents a disease entity distinct from the myotonia congenita of Thomsen, which is transmitted as an autosomal dominant trait. The clinical features of the two conditions are similar, apart from minor quantitative differences. The family history is the major tool for the differential diagnosis. The possibility of the detection of heterozygotes by electromyography is discussed.
A new variant of late‐onset myophosphorylase deficiency
Authors: Kost Gerald J. , Verity M. Anthony 
Published: January 2005

AbstractMcArdle disease classically presents in childhood or adolescence. Rarely does it become symptomatic for the first time in late adulthood, with the onset of progressive muscle wasting and weakness. Our patient is unusual in that despite a life of physical vigor, she developed immobilizing cramps, stiffness, and muscle swelling abruptly at age 60. She had no previous symptoms of muscle disease. The diagnosis was indicated by the ischemic forearm test, which produced muscle contracture and no rise in venous lactate levels, and confirmed by histochemical, electrophoretic, and biochemical studies that showed complete absence of myophosphorylase. This case defines a new variant of the late‐onset type and raises important questions about compensatory mechanisms, inheritance patterns, and etiological factors in myophosphorylase deficiency.
Abnormal myomuscular junctions and AChE in a congenital neuromuscular disease
Authors: Bormioli S. Pierobon , Lücke S. , Angelini C. 
Published: January 2005

AbstractWe studied a patient with a congenital neuromuscular disease clinically characterized by ophthalmoplegia, slight limb muscle weakness, and normal electromyography. In the muscle biopsy, there were frequent examples of interdigitation of areas of muscle and extracellular spaces giving a fragmented appearance to muscle fibers. These structures resemble myomuscular junctions; acetylcholinesterase activity was present in the vicinity of these structures and on the muscle cell surface.