bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental investigation of muscular neurotization in the rat
Authors: Must Rachel 
Published: January 2005

AbstractReinnervation of a free muscle graft by nerves from an adjacent intact muscle is called muscular neurotization. This paper investigates the mechanisms and stimuli responsible for muscular neurotization in the rat. Sternohyoid or sternomastoid muscles were transplanted as free muscle grafts to the ventral surface of an intact sternohyoid muscle (feeder muscle). After several weeks the graft and underlying feeder muscle were removed together, frozen, serially sectioned, stained, and carefully examined for the presence or absence of nerves. It was concluded from a series of experiments that in this model muscular neurotization is a form of nerve regeneration. In order for muscular neurotization to occur, it is necessary to have (1) injury to the nerves of the intact feeder muscle and (2) a pathway upon which the regenerating nerves may grow into the graft.
Enhanced release of ammonia and hypoxanthine from exercising muscles in patients with idiopathic hypoparathyroidism
Authors: Hara Naoko , Mineo Ikuo , Kono Norio , Shimizu Takao , Yamada Yuya , Kawachi Masanori , Suzuki Koyasu , Fukumoto Yasuaki , Tarui Seiichiro 
Published: January 2005

AbstractSemiischemic forearm exercise tests were carried out in two patients with idiopathic hypoparathyroidism who had muscle cramps and high serum levels of creatine kinase. Although cubital venous lactate levels increased normally after forearm exercise, venous ammonia and hypoxanthine were greatly increased. The abnormal responses of ammonia and hypoxanthine were normalized 3 months after treatment with 1 α‐hydroxyvitamin D3. These findings suggest that excess purine degradation occurred in exercising muscles of patients with idiopathic hypoparathyroidism.
Decreased plasmalogen ratios in cultured skin fibroblasts from myotonic dystrophy
Authors: Sakai Tetsuo , Antoku Yasunobu 
Published: January 2005

AbstractIt has become known that hypolipidemic agents, which can induce experimental myotonia in humans and animals, may alter the lipid metabolism of intracellular organelles, peroxisomes. However, there has been no reported study on peroxisomal lipid metabolisms in myotonic dystrophy showing myotonia as well as experimental myotonia. We investigated one of the peroxisomal lipid metabolisms, i.e., plasmalogen metabolism in cultured skin fibroblasts from myotonic dystrophy, and found plasmalogen ratios to be significantly reduced.
Membrane defects in paramyotonia congenita (eulenburg)
Authors: Lehmann‐Horn Frank , Rüdel Reinhardt , Ricker Kenneth 
Published: January 2005

AbstractMembrane potentials, current‐voltage relationships, and component conductances were determined in resting excised external intercostal muscle fibers from five patients with paramyotonia congenita. At 37°C all investigated parameters were normal. At 27°C the resting potentials decreased to about −40 mV, and the fibers were inexcitable. At this stage the membrane currents were much larger than in normal fibers owing to increases in the membrane conductances for Na and Cl ions. The earlier finding that in the cold the Na permeability is abnormally large was confirmed. The Cl permeability was shown to be normal even in the cold. The decrease of the resting potential and the changes in the current‐voltage relationship at 27°C could be prevented by the use of the Na channel blocker tetrodotoxin (TTX) or by bathing the fibers in a Na‐free solution. Our previous conclusion that the Cl conductance at 27°C was also increased when TTX was present was not confirmed. Exposure of a muscle bundle to 7 mmol/l potassium did not lead to excessive depolarization and paralysis.
AAEE minimonograph #28: Injury to peripheral motor nerves
Authors: Miller Robert G. 
Published: January 2005

AbstractNerve injury triggers a sequence of electrophysiological events dependent upon changes occurring both at the neuromuscular junction and the muscle membrane. The time course of these physiologic and morphologic alterations is reviewed in light of recent information provided by studies of extrajunctional acetylcholine receptors, axoplasmic transport, and freeze‐fracture electron microscopy. A thorough knowledge of these changes is essential to understanding the clinical impact of nerve injury.
Torpedo monoclonal antibodies react with components of the human peripheral nervous system
Authors: Bjornskov Elizabeth K. , Stephenson Diane T. , Kushner Pinky Drosten 
Published: January 2005

AbstractA panel of 141 monoclonal antibodies, generated to the Torpedo ray cholinergic nerve terminal preparation, were tested for binding to components of human nerve and muscle. Tested by immunofluorescence, 13 of the antibodies reacted with components of the human intercostal nerve, and 9 bound either muscle or blood vessels in a diversity of staining patterns. Results indicate that the antibodies identifiy a spectrum of different antigens. Some of the antibodies that cross react with the human nervous system have been studied in the ray and rat. In the human peripheral nerve and muscle, their cytochemical distribution is consistent with what has been observed in these other species. These antibodies, therefore, are likely to identify components of the neuromuscular junction that have been conserved in evolution from elasmobranches to humans. The antibodies identified here are potentially useful tools for a molecular examination of human nerves and muscles in pathological conditions.
Growth of skeletal muscle from patients with amyotrophic lateral sclerosis transplanted into nude mice
Authors: Gulati Adarsh K. , Rivner Michael H. , Shamsnia Morteza , Swift Thomas R. , Sohal Gurkirpal S. 
Published: January 2005

AbstractWe studied the fate of skeletal muscle obtained from patients with amyotrophic lateral sclerosis (ALS) after transplantation into immunodeficient nude mice. The transplanted muscle consistently survived in the nude mice without immunological rejection. The myofibers in these muscles underwent degeneration, followed by regeneration, maturation, and eventual functional innervation by the mouse motor neurons. The ability to grow diseased human muscle successfully over a prolonged period in nude mice offers an in vivo model to study the etiology of ALS and possibly of other neuromuscular disorders.
Myoplasmic free [Ca2+] during a malignant hyperthermia episode in swine
Authors: Löapez Jose R. , Allen Paul D. , Alamo Lorenzo , Jones Donald , Sreter Frank A. 
Published: January 2005

AbstractMalignant hyperthermia (MH) is a genetic syndrome usually initiated by exposure to volatile anesthetic agents or depolarizing neuromuscular blocking agents. We have used Ca2+‐selective microelectrodes to measure in vivo the intracellular ionized calcium ([Ca2+]i) in skeletal muscle fibers of MH‐susceptible swines before and during hyperthermic episodes and also after dantrolene administration. The animals were anesthetized with thiopental and fentanyl and maintained with a mixture of nitrous oxide (66%) and oxygen (34%). The malignant hyperthermic episode was triggered by exposure to halothane. Determinations of [Ca2+]i during the episode show an increase from 0.44 ± 0.01 μM ± SEM, n = 20 to 8.44 ± 0.68 μM (mean ± SEM, n = 10). Administration of dantrolene (2 mg/kg) during the hyperthermic episode reduces [Ca2+]i to 0.17 + 0.01 μM (mean ± SEM, n = 10) and reverses the clinical symptoms. These results show that the MH episode is associated with an increase in the myoplasmic free Ca2+ concentration and that the therapeutic effect of dantrolene is related to a decrease in [Ca2+]i.
Central motor conduction times using transcranial stimulation and F Wave latencies
Authors: Robinson Lawrence R. , Jantra Puangepeth , MacLean Ian C. 
Published: January 2005

AbstractThe purpose of this study was to determine central motor conduction times between the motor cortex and the C8 spinal cord level (MC/C8), the motor cortex and S1 cord level (MC/S1), and C8 and S1 (C8/S1). We stimulated 29 normal subjects with a transcranial high voltage (300–500 V), short duration spike wave form (time constant 50 μsec) and recorded over the hypothenar or calf muscles. F Wave and M response latencies were used to estimate peripheral conduction time. The mean MC/C8 conduction time was 4.4 ± 0.6 msec. Out of 26 subjects tested, 14 had discernable responses in the calf. The mean MC/S1 conduction time was 13.1 ± 2.5 msec, and the mean estimated C8/S1 conduction time was 8.5 ± 2.3 msec. This technique accurately measures conduction time from the motor cortex to the cervical anterior horn cells but is less reliable for monitoring conduction to the sacral cord. These values will facilitate future studies in patients with suspected lesions of the descending motor pathways.
Transient weakness and altered membrane characteristic in recessive generalized myotonia (Becker)
Authors: Rüdel Reinhardt , Ricker Kenneth , Lehmann‐Horn Frank 
Published: January 2005

AbstractThe isometric force of arm and leg muscles was studied in five unrelated patients with recessive generalized myotonia (Becker). The symptom of myotonia was present mainly in the legs, whereas transient weakness was the prominent symptom in the arms. Tocainide improved both symptoms, although it improved the stiffness more than the weakness. A specimen of intact muscle fibers was excised from the external intercostal muscle of one of the patients. The resting potential of the fibers was normal, but on injection of depolarizing current the fibers responded with repetitive action potentials. In normal interstitial fluid the current‐voltage relationship was N‐shaped, with a region of negative slope between −70and −55 mV. Replacement of chloride by an impermeant anion changed this relationship very little, suggesting an abnormally small chloride conductance. The potassium current through the inward‐going rectifier was larger than normal. The force of tetanic contractions of a rested bundle was not sustained but fell quickly to a plateau that increased with repeated stimulation. The relaxation of a rested tetanus was slow and accompanied by spontaneous electrical activity. In subsequent contractions the relaxation became faster and electrical after‐activity decreased. However at 23°C the speed of relaxation was always high despite a large amount of electrical after‐activity. The electrical instability of the membrane and the transient weakness can be explained on the basis of the N‐shaped membrane characteristic.
Effects of chronic prednisolone treatment on post junctional membrane responses to agonist
Authors: Ribera Angeles B. , Nastuk William L. 
Published: January 2005

AbstractUsing frogs treated 1 month with prednisolone, we studied responses of the muscle postjunctional membrane to acetylcholine and carbamylcholine. In control muscles following a bath application of 3 μM neostigmine or 30 μM pyridostigmine, there was an increased depolarization response to iontophoretically applied acetylcholine or carbamylcholine. Results with prednisolone‐treated frog muscle were essentially identical. In some fibers of prednisolone‐treated muscle there was a decrementing response to repetitive iontophoretic application of carbamylcholine. Prolonged administration of prednisolone may accelerate desensitization of acetylcholine receptors during repetitive application of agonist.
Lumbar radiculopathy after spinal fusion for scoliosis
Authors: Harper C. Michel , Daube Jasper R. , Litchy William J. , Klassen Rudolph A. 
Published: January 2005

AbstractIn 184 patients with no preoperative neurologic deficit who underwent operation for idiopathic scoliosis, somatosensory evoked potential monitoring was used. Four patients had neurologic deficits postoperatively. Two patients developed mild signs of intraspinal lesions involving upper motor neurons at high lumbar levels that resolved over 3–5 months. These patients and two others developed evidence of unilateral, moderate, lower motor neuron damage that was confirmed on electromyography. No changes in somatosensory evoked potentials occurred in these patients. Lumbar root damage may be difficult to recognize after operation and should be considered in patients with neurologic deficit after scoliosis surgery.
The myotonic mouse mutant ADR: Electrophysiology of the muscle fiber
Authors: Mehrke Gerhard , Brinkmeier Heinrich , Jockusch Harald 
Published: January 2005

AbstractThe hereditary neuromuscular syndrome of the mouse, “arrested development of righting response” (ADR), is characterized by after‐contractions of skeletal muscle. In order to analyze the etiology of this hereditary defect, mutant and wildtype muscle fibers were studied by intracellular recording. Direct stimulation of ADR muscle fibers elicited runs of action potentials of 1–5 seconds duration, with declining amplitudes and varying frequencies. The electrical after‐activity coincided with after‐contractions of the fiber, and both phenomena could be suppressed by the membrane‐stabilizing drug tocainide. Since similar runs of APs were observed with wildtype muscle in chloride‐free medium, the possible involvement of chloride conductance in the ADR syndrome was studied. Although membrane time constants in wildtype muscle were 4 times prolonged in chloride‐free medium, those of ADR muscle were only 1.4 times longer. This finding indicated a drastic reduction of chloride conductance of the ADR muscle membrane. We conclude that ADR is a myotonia, related in its etiology to hereditary myotonias of man.
The membrane lipid and fatty acid composition of erythrocyte ghosts from three patients with paramyotonia congenita
Authors: Marx Alexander , Szymanska Grażyna , Melzner Ingo , Rüdel Reinhardt 
Published: January 2005

AbstractThe membrane lipid and fatty acid composition of red blood cell ghosts from three paramyotonia patients was investigated. Cholesterol and total phospholipid contents were not different from the controls, but the sphingomyelin content was reduced, and this was compensated for by an increase in phosphatidylcholine. Thus, the molar ratios of phosphatidylcholine/sphingomyelin and phophatidylcholine/phosphatidylethanolamine were greater than normal. The saturated fatty acids in the total phospholipids were increased so that the ratio of saturated/unsaturated fatty acids was 1.4–1.6 versus 1.1–1.2 in the controls. The polyunsaturated fatty acids comprised only 22–26% of the fatty acids versus 31–32% in controls. The reduction in content of unsaturated fatty acids concerned all phospholipid classes in one patient and only the choline phospholipids in the two other patients who were related to each other. The pattern of the fatty acids in the C2‐position of the glycerophospholipids reflected the finding in the total phospholipids. Thus, an alteration of the activity of the acyl‐CoA: 1‐monoacylphosphoglyceride‐acyltransferase seems unlikely. The results support the notion of a generalized membrane defect in paramyotonia congenita, although the degree of abnormality in the fatty acid pattern was not correlated with the severity of the clinical symptoms.
Normal myoblast injections provide genetic treatment for murine dystrophy
Authors: Law Peter K. , Goodwin Tena G. , Wang Mary G. 
Published: January 2005

AbstractA treatment has been developed to alleviate muscle weakness in murine dystrophy. Cultured myoblasts from genetically normal mouse embryos were injected into the right soleus of 20‐day‐old normal or dystrophic mice. Hosts and donors were immunocompatible but exhibited different genotype markers. Donor cells produced GPI‐1CC. Host cells produced GPI‐1BB. When compared with contralateral controls 6 months postoperatively, test dystrophic solei exhibited greater cross‐sectional area, total fiber number, wet weight, and twitch and tetanus tensions. They contained more normal‐appearing and less abnormal‐appearing fibers. Their mean fiber resting potential was similar to that of normal controls. Presence of GPI‐1CC with or without the hybrid isozyme GPI‐IBC in these mucles implied the survival and development of donor myoblasts into normal myofibers, and fusion of normal myoblasts with dystrophic satellite cells to form genetically mosaic myofibers. Injection of fibroblasts instead of myoblasts caused detrimental effects.
Drug‐induced myotonia in human intercostal muscle
Authors: Kwiecińaski Hubert , Lehmann‐Horn Frank , Rüdel Reinhardt 
Published: January 2005

AbstractThe myotonia‐inducing effects of furosemide and clofibrate, two widely used pharmaceutical agents, were investigated in excised human external intercostal muscle. The effects of anthracene‐9‐carboxylic acid (9‐AC), a well‐known myotonia‐producing chemical, were also tested for comparison. In the presence of these drugs the electrical threshold was lowered, and a constant current pulse produced multiple spiking. Short trains of direct stimuli were often followed by after‐activity, and this caused a myotonia‐like prolongation of muscle contraction. Voltage‐clamp experiments showed that 0.05 mM anthracene‐9‐carboxylic acid, 1 mM furosemide, and 1 mM clofibrate decreased the chloride conductance of the muscle fiber membrane to 14, 18, and 40%, respectively, of the normal value, and the myotonia‐inducing potency of the 3 drugs was correlated with the decreased chloride conductance. The potassium currents were not affected by these compounds.
Adult human masseter muscle fibers express myosin isozymes characteristic of development
Authors: Butler‐Browne G. S. , Eriksson P.‐O. , Laurent C. , Thornell L.‐E. 
Published: January 2005

AbstractMasseter muscle biopsies were obtained from nine patients undergoing orthognatic surgery or surgery for parotid tumors. A detailed enzyme‐histochemical and immunocytochemical study of these muscles was performed using antibodies specific to the various isozymes of the myosin heavy chain (MHC) in order to identify the MHC isozymes that were present in the different fiber types. The contractile proteins in these same biopsies were analyzed by two‐dimensional gel electrophoresis, native pyrophosphate gel electrophoresis, and by an immunopolypeptide mapping approach. These studies have shown that there is a very heterogeneous distribution of the myosin isozymes, with many fibers containing more than one myosin type. We also present evidence that in addition to adult fast and slow myosin, the human masseter muscle contains two proteins, neonatal MHC and embryonic myosin light chain, that are characteristic of developing muscle.
Changes in denervated skeletal muscle of amiodarone‐fed mice
Authors: Costa‐Jussà Frederic R. , Guevara Ana , Brook Gary A. , Duchen Leo W. , Jacobs Jean M. 
Published: January 2005

AbstractProlonged dosing of mice with amiodarone produced a myopathy characterized by autophagic vacuolation and phospholipid inclusions. A previous morphological study had shown that amiodarone did not affect the rate of nerve regeneration after sciatic nerve crush. In the present study, reinnervation was assessed by the reappearance of miniature endplate potentials that confirmed that axonal regeneration and motor reinnervation was not affected by amiodarone. However, there was a marked delay in the recovery of motor function in the amiodarone‐treated mice. Denervation was found to induce an extensive necrosis of muscle fibers in the deeper parts of fast‐twitch muscles. Histochemical studies showed that type 1 fibers were spared, necrosis affecting mainly type 2 fibers with relatively high oxidative enzyme activity (fast‐twitch oxidative fibers). Biochemical studies showed a significant increase in the amount of amiodarone and its metabolite in denervated muscle of amiodarone‐treated mice when compared with contralateral, normally innervated muscles.
Prognostic value of electrodiagnosis in Guillain‐Barré syndrome
Authors: Miller Robert G. , Peterson Gordon W. , Daube Jasper R. , Albers James W. 
Published: January 2005

AbstractThis study was designed to identify clinical and electrodiagnostic indicators of prognosis in Guillain‐Barré syndrome (GBS). Sixty severe GBS patients (all bedfast, 22 ventilator dependent) were analyzed clinically and with standard electromyography and nerve conduction studies. Both ventilator dependence and rapid evolution of weakness were more common in patients with a poor prognosis. The most powerful predictor of a poor outcome was reduced mean compound muscle action potential amplitude (less than 10% of the lower limit of normal).
Investigation of scoliosis in duchenne dystrophy using computerized tomography
Authors: Stern L. M. , Clark B. E. 
Published: January 2005

AbstractIn order to determine the role of the spinal muscles in the etiology of the scoliosis associated with Duchenne muscular dystrophy, we carried out a study of 16 children using computerized tomography. Scans were taken at the level of the 9th dorsal and the 3rd lumbar vertebrae. Density readings were taken in the medial and lateral portions of the erector spinae. The results confirmed the loss of muscle and replacement by fat which was greater on the concave side. The density differences between the convex and concave sides correlated with the degree of curvature measured by Cobb's method. Computed tomography may offer a prognostic indicator in the development of scoliosis.
Therapeutic trial of isaxonine in duchenne muscular dystrophy
Authors: Heckmatt J. Z. , Hyde S. A. , Gabain A. , Dubowitz V. 
Published: January 2005

AbstractA randomized double‐blind therapeutic trial of isaxonine was completed over a 2‐year period for 20 ambulant boys with Duchenne muscular dystrophy aged 5 1/2–10 years. The effect of the drug was monitored by measurement of walking times over 28 and 150 ft, motor ability score, MRC score based on 32 muscle groups, and myometry of 7 muscle groups. The drug had no significant effect on the progression of the disease. The trial had statistical power comparable to previous larger‐scale multicenter trials. This reflected the low variability in the patients in relation to the magnitude of the overall deterioration. Measurements of muscle force (myometry and MRC score) had much greater statistical power than measurements of function (motor ability score and walking times) as analyzed by our methods. These observations have important implications for the design of future trials.
Axonal branching following crush lesions of peripheral nerves of rat
Authors: Toft Peter B. , Fugleholm Kåre , Schmalbruch Henning 
Published: January 2005

AbstractBranching of myelinated and unmyelinated nerve fibers in normal and regenerating peroneal and soleus nerves was studied by light and electron microscopy. There were at most 2% more myelinated and 13% more unmyelinated axons in the distal as compared with the proximal nerve segments. Two to four weeks after a crush lesion the distal axons became 2–3 times more numerous; thereafter their number decreased. The number of axons in the proximal nerve segment did not change. The number of myelinated sprouts in most regenerated nerves equalled the number of myelinated fibers in the proximal nerve, while the number of unmyelinated axons after 12–19 weeks was 18–60% higher than normal. Branching was not restricted to the crush region. The results indicate that following a crush lesion all axons branch but only branches of unmyelinated fibers persist for a prolonged period of time. It is tentatively suggested that regenerating axons branch when searching for a target and that when contact is made with the target this prevents additional branching and eliminates redundant branches. Myelinated axons are guided by existing Schwann cells, whereas unmyelinated axons do not follow predetermined pathways; this may explain their greater tendency to form permanent branches.