bluuebunny/crossref_metadata_2025_split huggingface dataset:
Desmin and vimentin in regenerating muscles
Authors: Bornemann Antje , Schmalbruch Henning 
Published: January 2005

AbstractDesmin is a normal constituent of skeletal muscle fibers; vimentin is contained in myoblasts and connective tissue cells. The intracellular localization of both intermediate filament proteins in regenerating rat muscles was investigated by immunohisto‐ and immunocytochemistry. Necrosis was induced by hot Ringer solution. Desmin and vimentin were diffusely distributed in myoblasts and young myotubes. Both proteins became arranged in a sarcomeric fashion between the Z‐lines when the sarcomeres got into register. Desmin reactivity persisted, but vimentin disappeared after about 2 weeks. Traces were found for up to 4 weeks. This observation is in contrast to findings in fetal and cultured muscles in which several authors did not find expression of vimentin after myoblast fusion. The presence of vimentin may well be a useful marker for regenerated muscle fibers in muscle biopsies from patients with neuromuscular disorders.
Muscle excitation in elderly adults: The effects of training
Authors: Hicks Audrey L , Cupido Cynthia M. , Martin Joan , Dent Jennifer 
Published: January 2005

AbstractMuscle membrane excitability is thought to decline with aging; the extent of this decline may be noninvasively assessed by measurement of the electrically evoked compound muscle action potential (M‐wave). The intent of this study was two‐fold: (1) to compare the M‐wave in the brachioradialis (BR), tibialis anterior (TA), and thenar (TH) muscles of elderly (mean age = 66.3 ± 3.7 years) and young (mean age = 31.2 ± 4.9 years) adults, and (2) to determine the effects of 12 weeks of resistance training on M‐wave characteristics in elderly adults. Prior to training, the elderly subjects had significantly smaller (P < 0.05) resting M‐waves than the young adults in the BR (4.8 mV vs. 8.7 mV), TA (8.8 mV vs. 11.0 mV), and TH (5.2 mV vs. 10.2 mV) muscles. During a 2‐minute voluntary fatigue paradigm (3 seconds MVC per 2 seconds rest for 2 minutes), there was no evidence of excitability failure in either group. Following training, there was a significant increase (P < 0.05) in the size of the M‐wave of the TH (pretraining: 5.2 mV; posttraining: 8.96 mV) and BR (pretraining: 4.8 mV; posttraining: 6.1 mV), and a nonsignificant increase in the M‐wave of the TA, but there was no change in the relative behavior of the M‐wave during the 2‐minute voluntary fatigue paradigm, It is suggested that the decline in muscle membrane excitation with aging may be due, at least in part, to the effects of a decreased membrane potential on the muscle fiber action potential. Furthermore, our results suggest that exercise training may improve muscle excitability in elderly adults, possibly reflecting a training‐induced increase in the resting membrane potential due to an increased activity and/or concentration of the skeletal muscle Na+K+‐ATPase.
Repetitive nerve stimulation vs. twitch tension in rats with EAMG
Authors: Thompson Patricia A. , Barohn Richard A. , Krolick Keith A. 
Published: January 2005

AbstractTwo methods were compared with regard to their ability to detect acetylcholine receptor‐dependent neuromuscular dysfunction in rats with experimental autoimmune myasthenia gravis. In both cases, detection of AChR impairment required amplification of symptoms by administration of the AChR antagonist curare and appeared to be directly related to increasing levels of circulating anti‐AChR antibodies. First, in vivo evaluations of decremental compound motor action potentials following repetitive nerve stimulation were performed by electromyography. Impaired neuromuscular function (i.e., >10% decrement) was noted only after rats had been immunized twice with AChR, requiring levels of circulating anti‐AChR antibody greater than about 200 μg/mL in serum. In contrast, the direct in vitro evaluation of stimulated isometric twitch tension appeared to be more sensitive in that impaired AChR‐dependent muscle contraction was clearly observed following a single AChR immunization, and, as shown previously, required anti‐AChR antibody levels of about 50 μg/mL in serum. Further discussion is presented concerning the advantages and disadvantages associated with each method of monitoring disease.
Voluntary discharge frequencies of human motoneurons at different muscle lengths
Authors: Bigland‐Ritchie Brenda R. , Furbush Frank H. , Gandevia Simon C. , Thomas Christine K. 
Published: January 2005

AbstractThe relationship between the discharge frequencies of motoneurons and the voluntary force at high contraction strengths (50% to 100%maximum) was determined for tibialis anterior with the ankle: (i) at 90° (control length) and (ii) this angle reduced by about 15° (short length), an amount sufficient to reduce the maximal voluntary force by about 35%. In the shortened position, twitch contraction and half‐relaxation times were reduced by 11% and 18%, respectively. At both muscle lengths, the ability to activate the muscle fully by voluntary effort was confirmed by twitch interpolation. Motor unit firing rates were recorded during isometric voluntary contractions lasting 10 seconds, performed at 50%, 75%, and 100% maximal force. At each length, discharge rates varied in proportion to the relative force exerted. Despite the difference in twitch contractile speed at the two lengths, no significant differences were found between motoneuron discharge rates recorded at each muscle length during maximal or submaximal contractions.
Ca2+—ATPase and Na+‐K+–ATPase content in skeletal muscle from malignant hyperthermia patients
Authors: Everts Maria E. , Ørding Helle , Hansen Otto , Nielsen Peter A. 
Published: January 2005

AbstractThe purpose of this study was to determine the concentration of Ca2+–ATPase and Na+‐K+–ATPase in biopsies from vastus lateralis muscle of 24 patients, who underwent a diagnostic contracture test for susceptibility to malignant hyperthermia (MH). Ca2+–ATPase was quantified as the Ca2+‐dependent 32P incorporation in whole muscle homogenates. Na+‐K+–ATPase was quantified as the [3H]ouabain‐binding capacity in intact muscle samples. These methods avoid isolation of membranes, a procedure that may influence the results due to interindividual variation in recovery. The results show that both enzymes can be determined in (frozen) muscle biopsies weighing 50 mg. Neither the concentration of Ca2+–ATPase nor that of Na+‐K+–ATPase differed in biopsies from subjects diagnosed as susceptible (MHS) or nonsusceptible (MHN) to MH. Our data support the view that changes in the concentration of Ca2+–ATPase and/or Na+‐K+–ATPase do not play a primary role in the pathogenesis of MH.
Quality control in nerve conduction studies with coupled knowledge‐based system approach
Authors: Xiang Yang , Eisen Andrew , MacNeil Maureen , Beddoes Michael P. 
Published: January 2005

AbstractContemporary equipment used for nerve conduction studies is usually capable of computerized measurement of latency, amplitude, duration, and area of nerve and muscle action potentials and resulting conduction velocities. Abnormalities can be due to technical error or disease. Identification of technical error is a major element of quality control in electromyography, and artificial intelligence could be useful for this purpose. We have developed a coupled knowledge‐based prototype system (QUALICON) to assess the correctness of recording and stimulating characteristics in routine conduction studies. QUALICON extracts numeric features from CMAPs or SNAPs, which are translated into symbolic form to drive a Bayesian network. The network uses high‐level knowledge to infer the quality of stimulating and recording electrode placement as well as polarity and stimulus strength making recommendations as to the likely technical error when abnormal potentials are detected. A preliminary assessment shows that QUALICON performs as well as manual assessment performed by professionals.
Segmental cytochrome c‐oxidase deficiency in CPEO: Teased muscle fiber analysis
Authors: Matsuoka Taro , Goto Yu‐Ichi , Hasegawa Hitomi , Nonaka Ikuya 
Published: January 2005

AbstractIn an attempt to elucidate the pathogenesis of focal cytochrome c‐oxidase (COX) deficiency in skeletal muscle from patients with chronic progressive external ophthalmoplegia (CPEO), we examined the longitudinal distribution of COX activity in single muscle fibers from 6 CPEO patients with muscle mitochondrial DNA (mtDNA) deletions. A new method for teasing single muscle fibers, recently developed in our laboratory, revealed fibers with COX‐positive and ‐negative segments in all 6 patients. The borders between the enzyme‐positive and ‐negative segments in these fibers were sharply delineated, so that the length of each COX‐negative segments could be accurately measured. The proportion of the sum of the lengths of the enzyme‐negative segments to the total length of the muscle fibers correlated well with the proportion of deleted mtDNA, suggesting that abnormal mitochondria harboring mutant mtDNA may be responsible for the focal loss of COX activity.
Brief communication: Becker muscular dystrophy: Detection of unusual disease courses by combined approach to dystrophin analysis
Authors: Gold Ralf , Kress Wolfram , Meurers Bernd , Meng Gerhard , Reichmann Heinz , Muüller Clemens R. 
Published: January 2005

AbstractThe rapid progress of research on the structure of the dystrophin gene has enormously increased our understanding of the molecular basis of Duchenne (DMD) and Becker (BMD) muscular dystrophy. Apart from “classical” clinical presentations, asymptomatic or only mildly affected individuals with deletions in the dystrophin gene have now been reported. We describe two families which were initially classified as metabolic myopathies, until the diagnosis of atypical BMD was established after dystrophin analysis at the protein and DNA level. A modern diagnostic approach to myopathies should, therefore, not only include morphological and biochemical investigations, but also be extended to the analysis of the dystrophin gene.
Amyotrophic lateral sclerosis (ALS): A phylogenetic disease of the corticomotoneuron?
Authors: Eisen Andrew , Kim Seung , Pant Bhanu 
Published: January 2005

AbstractIt is proposed that the primary cell involved in amyotrophic lateral sclerosis (ALS) is the corticomotoneuron. The spinal motoneuron becomes affected as a result of antegrade effects. This hypothesis does not negate most of the presently popular theories regarding the pathogenesis of ALS, but directs focus to one cell type–the corticomotoneuron. It takes cognizance of the complex, monosynaptic, corticomotoneuronal‐spinomotoneuronal connections that have evolved in primates, and especially in man. It might explain the lack of any natural or thus far induced animal model which closely mimics the human disease. Threshold measurements to transcotical magnetic stimulation might be used to test the hypothesis. Replication of ALS in an animal is only likely to succeed in a nonhuman primate.
A congenital myasthenic syndrome refractory to acetylcholinesterase inhibitors
Authors: Triggs William J. , Beric Aleksandar , Butler Ian J. , Roongta Suresh M. 
Published: January 2005

AbstractWe studied 4 siblings (3 men and 1 woman), ages 22 to 43 years, with congenital ptosis, external ophthalmoplegia, proximal muscle weakness and fatigability unresponsive to acetylcholinesterase (AChE) inhibitors. Repetitive nerve stimulation showed a significant compound muscle action potential (CMAP) area decrement at 2 or 3 Hz. Nerve conduction studies and concentric needle electromyography were normal, and repetitive CMAPs to single nerve stimulation were not observed. Voluntary single fiber electromyography (SFEMG) showed increased jitter and blocking. Assessment of individual end‐plates using SFEMG with intramuscular axonal microstimulation showed no uniform relationship between jitter and the rate of stimulation, consistent with a postsynaptic defect of neuromuscular transmission. Edrophonium eliminated the decremental response to repetitive nerve stimulation, but caused no significant clinical improvement, suggesting an additional mechanism for weakness in these patients.
Role of autonomic nerve functions in patients with familial amyloidotic polyneuropathy as analyzed by laser doppler flowmetry, capsule hydrograph, and cardiographic R–R interval
Authors: Ando Yukio , Araki Shukuro , Shimoda Osamu , Kano Tatsuhiko 
Published: January 2005

AbstractLaser Doppler flowmetry (LDF) was conducted on familial amyloidotic polyneuropathy (FAP) patients and asymptomatic carriers of FAP. Vasoconstrictive responses in the 11 FAP patients tested, induced by deep inspiration, were markedly depressed compared with those of the healthy controls. The responses decreased with the progression of FAP, with no responses being elicited from the 7 patients in stages 2 (moderate) to 4 (terminal). Interestingly, vasoconstrictive responses following deep inspiration also were depressed in 3 of 4 asymptomatic carriers of FAP who showed no clinical sign of FAP, and who had normal sensory nerve conduction velocity. Patients who had such diseases as Shy–Drager's disease, spinocelebellar degeneration, and pandysautonomia showed no decrease in blood flow for various stimulations. In contrast, patients with primary amyloidosis, who had no autonomic dysfunction, showed a normal pattern. Detection of the autonomic functions in FAP patients and asymptomatic carriers by capsule polyhydrography and computer analysis of the cardiographic R–R interval revealed that the asymptomatic carriers of FAP, as well as the FAP patients, had disordered peripheral autonomic functions. Our results suggest that the autonomic nervous system is first affected during the very early stage of FAP.
Determining neuromuscular jitter using a monopolar electrode
Authors: Buchman Aron S. , Garratt Mark 
Published: January 2005

AbstractNeuromuscular jitter was determined in the extensor digitorum communis (EDC) of 41 healthy control subjects and 8 patients with myasthenia gravis (MG). Standdard single‐fiber electromyographic (SFEMG) techniques were used, except that a monopolar electrode (MPE) was substituted for a single‐fiber electrode (SFE). In normals, means jitter for 20 pairs was 22.4 ± 2.8 μs and the mean jitter for an individual pair was 22 ± 5.6 μs. In the age range tested (18 to 49 years), jitter did not change with increasing age. When MPE jitter studies were repeated in 16 normals, mean jitter usually varied by less than 10% (mean 7.4% ± 6.2%) and remained normal. Jitter was significantly increased in MG compared to normals 73 ± 56 μs versus 22 ± 5.6 μs (F = 149.4, P < 0.0001). Using an analog pain scale, the discomfort during electromyography using MPE and SFE was compared between the left and right arms in 35 normals. MPEs caused less discomfort than SFEs (P = 0.031), and were preferred (71% versus 20%) to SFEs (χ2 = 9.21, P = 0.01). Based on these results, we conclude that MPE determined jitter studies are reproducible, can distinguish between nomals and MG, and are associated with less discomfort than SFE.
Sural nerve conduction parameters in normal subjects related to age, gender, temperature, and height: A reappraisal
Authors: Trojaborg Werner T. , Moon Agnes , Andersen Birgitte B. , Trojaborg Nanna S. 
Published: January 2005

AbstractFailure to take body height into considerations in the evaluation of nerve conduction velocities (CV) has recently been deemed unacceptable. This statement prompted the present study. Besides height, the influence of age, gender, and temperature was studied in 92 normal subjects, half of whom were females. The CV decreased 0.9 m/s per 10 years increase in age, the same in women and men aged 15 to 44 years. Mean temperature between distal and proximal ends of the nerve segment examined increased 6.1 ± 0.3° C after heating followed by a CV increase of 7.0 ± 0.5 m/s. The CV decreased 0.15 m/s per 100‐mm increase in heights. When considering 37 individuals aged 25 to 34 years only, the CV increased 0.34 m/s per 1‐m increase in height. In both instances, the changes were within the experimental error (2.3%) of the method.
Early postoperative ulnar neuropathies following coronary artery bypass surgery
Authors: Watson Bradley V. , Merchant Richard N. , Brown William F. 
Published: January 2005

AbstractUlnar neuropathies following surgery are common. However, they often go undetected during the early postoperative period, because the patient may be unaware of symptoms related to the neuropathy. Nerve conduction studies are useful in localizing the lesion, but are usually employed only in cases developing signs and symptoms. We undertook this study to determine the incidence, time of onset, and outcome of clinical and subclinical ulnar neuropathies. Electrophysiological studies were carried out preoperatively, imediately following surgery, and 4 to 6 weeks postoperatively in 20 coronary artery bypass patients. Conduction velocity across the elbow was reduced in 3 limbs (8%) postoperatively, all of which were detected immediately following surgeery. One parient developed conduction block and weakness in ulnar supplied intrinsci hand muscles. Denervation was seen in 2 cases and, in 1 case (5%), a right brachial plexus injury was clinically evident 5 days following surgery. All newly developing ulnar neuropathies were asymptomatic, with most recovering to their preoperative electrophysiological status at follow‐up.
Amiodarone‐induced experimental acute neuropathy in rats
Authors: Santoro Lucio , Barbieri Fabrizio , Nucciotti Renato , Battaglia Francesco , Crispi Francesco , Ragno M. , Greco P. , Caruso G. 
Published: January 2005

AbstractAmiodarone was injected endoneurially at increasing doses into the exposed tibial nerve of rats to study its electrophysiologic and pathologic effects on peripheral nerve fibers. Forty‐five male Wistar rats were used, and each of the following concentrations was injected into 15 nerves: 25 μg/mL, 50 μg/mL, and 100 μg/mL. Microinjection of a 25 μg/mL concentration of amiodarone resulted in a subacute, incomplete conduction block evident at day 3 postinjection. This conduction block remained stable until day 10 and recovery was complete at day 35. Microinjection of a 50 μg/mL concentration of amiodarone produced a faster evolving conduction block, and significant axon degeneration (approximately 40% of fibers). Injection of a 100 μg/mL concentration resulted in severe acute motor axon degeneration followed by complete but delayed regeneration. Results of morphological studies closely correlated with electrophysiological findings. Amiodarone thus seems to have a direct toxic effect on axons at high concentrations in the peripheral nerve, and we suggest that different pathological changes described in human amiodarone neuropathy could be related to different concentrations of the drug in the nerve, perhaps due to variability of blood‐nerve barrier efficacy.
Lumbosacral nerve root stimulation comparing electrical with surface magnetic coil techniques
Authors: MacDonell R. A. L. , Cros D. , Shahani B. T. 
Published: January 2005

AbstractStimulation of lumbosacral nerve roots using a monopolar needle electrode was compared with magnetic stimulation using a 7‐cm diameter surface coil. Compound muscle action potentials were recorded from the tibialis anterior (TA) and flexor hallucis brevis (FHB) muscles. Although the mean latency of CMAPs did not differ using the two techniques, amplitudes were considerably larger using a needle. Mean amplitudes were 66% (TA) and 64% (FHB) of the direct M response obtained by distal, supramaximal stimulation compared with mean values using maximal magnetic coil stimulation of 36% (TA) and 25% (FHB). Minimum F‐wave latencies from FHB were used to estimate the site of nerve root stimulation using both techniques. Although there was a large amount of variability in the data from individual subjects, the results suggested that, on the average, both forms of stimulation act proximal to the intervertebral foramen. We conclude that a needle electrode is a more suitable technique for stimulating lumbosacral nerve roots. © 1992 John Wiley & Sons, Inc.
Increasing the proliferative capacity of muscular dystrophy myoblasts
Authors: Yang Jie , Seelig Miriam , Rayner Sylvia , Bredesen Dale E. 
Published: January 2005

AbstractTemperature‐sensitive immortalized neural cells may be utilized to produce genetically engineered neural transplants. We have used a similar approach with mdx myoblasts. Control and mdx myoblasts were immortalized with a recombinant retrovirus that effects the expression of a temperaturesensitive simian virus 40 large T antigen. The resultant cells divide indefinitely at 34°C, but differentiate at 38°C, both morphologically and immunocytochemically. Polymerase chain reaction analysis of RNA confirmed the presence of the dystrophin point mutation in the mdx cells and its absence in the control cells. A similar approach may be useful for the proliferation, modification, and reimplantation of autologous cells from patients with degenerative and dystrophic disorders such as Duchenne muscular dystrophy. © 1992 John Wiley & Sons, Inc.
Far‐field potentials in circular volumes: The effect of different volume sizes and intercompartmental openings
Authors: Dumitru Daniel , King John C. 
Published: January 2005

AbstractPreliminary investigations of circular volume conductors suggested that farfield potential magnitude declines progressively slower with increasing radial distance from a current source and follows a cosine function with angular displacement of the recording electrode from the electrical generator's axis. Using circular volumes of 6 differing radii, the mathematical relationship between angle, radii, and far‐field potential amplitude is determined. Previous theoretical relationships of amplitude versus dipolar spacing, current, and distance from a dipole generator in a bounded volume conducting medium are verified for the near‐field. Far field potentials in circular volumes are found to become constant at radii greater than 75% of the bounded volume's radius. Additionally, an adjoining volume conductor acts simply as a passive fluid‐filled electrode (wick electrode) to the circular volume containing the generator until the intercompartmental opening to the circular volume exceeds 20% of its circumference. This finding was clinically supported by recording similar P9 somatosensory‐evoked far‐field potentials generated caudal to the foramen magnum from various portions of the cranium, whose connections to the torso, foramen magnum, and neck, average 6.2% and 17.8%, respectively. Finally, 3 circular volume conductors were connected in series by channels less than 20% of the volume conductor's circumference. Both adjoining circular volumes were equipotential to the far‐field potential present at the boundary of the first circular volume containing the dipole generator. This observation supports the clinical finding of far‐field potential transmission through multiple human bodies in conductive contact. © 1992 John Wiley & Sons, Inc.