bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nerve conduction studies in the superficial in the superficial radial nerve entrapment syndrome
Authors: Spindler Henery A. , Dellon A. Lee 
Published: January 2005

AbstractThis report reviews the ssyndrome of entrapment of the superficial branch of the radial nerve (SBRN) in the forearm, and electrodiagnostic techniques to aid in diagnosis are presented. Normal mean radial sensory conduction in the forearm was found to be 61.4 ± 3.1 m/sec. Three patients are presented. In two of these comparison of conduction in the SBRN to the lateral antebrachial cutanious nerve (LACN) and contralateral SBRN was abnormal, whereas the absolute SBRN conduction appeared normal. Normal LACN‐SBRN difference in the same arm was 1.9 ± 1.6 m/sec, with a range of 0–7.0 m/sec; mean SBRN difference in opposite arms of the same subject was 1.8 ± 1.6 m/sec.
Rat and human Schwann cells in vitro can synthesize and express MHC molecules
Authors: Armati P. J. , Pollard J. D. , Gatenby P. 
Published: January 2005

AbstractThe expression of MHC class I and II molecules on cultured rat and human Schwann cells (SCs) was studied to determine whether these molecules could be synthesized by SCs in the absence of T cells. Normal rat and human SCs in vitro expressed low levels of class I MHC, but this was markedly increased by incubation with interferon gamma (IFN‐γ). Untreated SCs of rat or human origin did not express detectable class II MHC molecules, but after 48 hours incubation with IFN‐γ 100 U/ml, 20% of rat SCs and 90% of human SCs were class II positive. Immunoelectron microscopy confirmed the surface expression of MHC molecules on SCs and demonstrated class II MHC within endocytotic vesicles. These findings provide further evidence for an immunological role for SCs as antigen presenting cells or as targets for cytotoxic T cells.
Effect of clenbuterol on normal and denervated muscle growth and contractility
Authors: Agbenyega Edward Tsiri , Wareham Anthony Clive 
Published: January 2005

AbstractThe reported anabolic action of some β2 agonists may have clinical applications in certain muscle wasting states. Administration of clenbuterol (2mg/kg diet for 14 days) to rats resulted in a limited degree of hypertrophy of normal muscles; the effect was more pronounced on fast‐twitch muscles than on slow‐twitch muscles. The anabolic effect was greatest in denervated muscles, where it was significantly more effective on the slow‐twitch type. Clenbuterol significantly improved the contractile properties of denervated slow‐twitch muscle, reverting them toward normal, but had little effect on contractile properties of denervated fast‐twitch muscle. Such differential effects of clenbuterol must be taken into consideration in the evaluation of any future human intervention study.
Polyneuropathy in lithium intoxication
Authors: Vanhooren Geert , Dehaene Ides , Van Zandycke Michel , Piessens Frans , Vandenbergh Vic , Van Hees Johan , Lammens Martin , Carton Herwig 
Published: January 2005

AbstractTwo patients developed acute sensorimotor polyneuropathy after intoxication with lithium carbonate. Nerve conduction studies, electromyography, and sural nerve biopsy proved it to be an axonal neuropathy. Recovery of muscle strength, reflexes, and sensory function started weeks after discontinuation of lithium therapy. One patient fully recovered within a year. In the literature we found nine other cases of lithium polyneuropathy.
The expression of myosin light chains and tropomyosin in human muscle biopsies with histochemical type 1 and type 2 fiber deficiency
Authors: Giometti Carol S. , Danon Moris J. 
Published: January 2005

AbstractTwo‐dimensional gel electrophoresis (2DE) was used to compare the protein composition of human muscle biopsies that were shown by histochemical staining to be deficient in either type 1 or type 2 fibers. Distinct quantitative differences were found in the myofibrillar protein composition of muscle from a 43‐year‐old woman with proximal limb weakness that showed almost total absence of type 1 fibers and muscle from a 2.5‐year‐ girl with congenital myopathy in which there was severe lack of type 2 fibers. These data indicate that human type 1 and type 2 muscle fibers express distinct isoforms of myosin light chains and α‐tropomyosin.
Hypertrophic mononeuritis clinically presenting with painful legs and moving toes
Authors: Mitsumoto Hiroshi , Levin Kerry H. , Wilbourn Asa J. , Chou Samuel M. 
Published: January 2005

AbstractA 40‐year‐old woman presented with progressive lower leg pain and spontaneous toe movement. The EMG showed a posterior tibial nerve mononeuropathy and continuous myokymic discharges in posterior tibial‐innervated muscles. The MRI revealed a markedly enlarged posterior tibial nerve. Toe movements and myokymia were unaffected by the proximal transection of the lesion but ceased abruptly when the distal end of the fusiform “tumor” was resected, suggesting that spontaneous electrical foci may have been located along the nerve lesion. The markedly enlarged nerve segment contained edematous, swollen fascicles with marked Schwann cell onion‐bulb lesions and angiocentric, lymphocytic, and lymphofollicular infiltration. This nerve lesion is an example of a newly recognized entity called hypertrophic mononeuritis.
The correlation between electrical after‐activity and slowed relaxation in myotonia
Authors: Iaizzo Paul A. , Lehmann‐Horn Frank 
Published: January 2005

AbstractThe correlation between electrical and mechanical after‐activity was studied in resealed fiber segments from patients with recessive generalized myotonia (Becker) and in intact fibers from normal muscles which were bathed in 9‐anthracene carboxylic acid. The tests were performed in vitro on small bundles of 100 fibers or less. Electromyographic activity and contractile force were measured simultaneously. The relaxation of rested‐state twitches and tetani was slowed and accompanied by after‐activity in both types of preparations. Often random activity was recorded. In all cases, the contractile force was highly correlated with the electromyographic signs of myotonia. These observations support the hypothesis that electrical afteractivity is fully responsible for the slowed relaxation in recessive generalized myotonia.
Temperature dependence of the electrical and mechanical responses of the adductor pollicis muscle in humans
Authors: Hopf Hanns Christian , Maurer Konrad 
Published: January 2005

AbstractChanges at low temperatures of the electrical and mechanical activity of the adductor pollicis muscle were studied in 10 volunteers. Decreasing temperatures resulted in increased amplitude and duration of the negative phase and peak‐to‐peak amplitude of the evoked muscle action potential. Distal latency, electromechanical latency, contraction time, and half‐relaxation time were also increased while isometric force, contraction velocity, and relaxation velocity were decreased. The increase of contraction time is greater over the temperature range below 28°C than above 29°C. Skin temperature differs significantly from muscle temperature, showing about 3°C lower values during cooling and up to 4°C higher values during rewarming with radiant heat.
Differential expression of nuclear genes for cytochrome c oxidase during myogenesis
Authors: Lomax Magaret I. , Coucouvanis Electra , Schon Eric A. , Barald Kate F. 
Published: January 2005

AbstractRecent studies of patients with mitochondrial myopathies suggest the existence of both muscle‐specific and developmentally regulated isoforms of cytochrome c oxidase (COX), the terminal enzyme complex of the electron transport chain. To investigate the temporal pattern of gene expression of nuclear genes for COX in developing muscle, the steady‐state levels of COX mRNA in total RNA from a satellite cell‐derived mouse muscle cell line, C2C12, were analyzed and compared with COX mRNA levels in mature rat skeletal muscle. Undifferentiated myoblasts, myotubes just after fusion (early myotubes), and fully differentiated, contractile, striated myotubes (late myotubes) were analyzed for mRNA levels for four of the 10 different nuclear‐encoded COX subunits: IV, Vb, VIc and VIII‐liver. Of these, IV, Vb and VIc are identical in both bovine heart and liver, whereas subunit VIII has heart and liver isoforms. In C2C12 myoblasts, the level of mRNA for subunits IV, Vb, and VIII‐liver is equal to or greater than the level in tissues such as brain, skeletal muscle, and liver. As myoblasts fuse and differentiate into myotubes, the levels of mRNA for these subunits undergo radically different changes. Transcripts for subunits IV and Vb accumulate to higher levels during myogenesis. The level of subunit VIII transcripts decreases during myogenesis, providing additional evidence that subunit VIII has tissue‐specific isoforms in the rat. Little mRNA for COX VIc was detected in either the C2C12 cell line or in primary embryonic rat myoblasts or myotubes in culture in spite of high levels in adult skeletal muscles, suggesting that subunit VIc may have both fetal and adult isoforms in rodents.
Calcium channel blocker influences the density of alpha‐actinin labeling at the rat neuromuscular junction
Authors: Meshul Charles K. , Kriho Virginia , Kriho Nicholas , Hopkins William F. , Matsumura Fumio , Pappas George D. 
Published: January 2005

AbstractAlpha‐actinin is a muscle protein located along the Z‐disc. Incubation of frog muscle with the calcium ionophore, A23187, can decrease the immunogold labelling of alpha‐actinin.14 Pyridostigmine (PYR) is an inhibitor of acetylcholinesterase, which causes disruption of Z‐discs only in the region of the motor endplate. This is probably due to excess influx of calcium ions, leading to activation of proteases. Pretreating animals with the calcium channel blocker diltiazem can significantly reduce damage to the Z‐discs at the motor endplate caused by PYR. It was of interest to determine whether the distribution of alpha‐actinin had been altered following PYR administration and whether diltiazem could prevent those changes. There was less alpha‐actinin labelling at the motor endplate compared to away from this region for all treatment groups. Animals administered diltiazem showed less labelling compared to PYR, but with no disruption of Z‐discs at the motor endplate following diltiazem. Pretreatment with diltiazem reduced the incidence of Z‐disc damage, but the degree of alpha‐actinin labeling at the endplate was less than that seen with diltiazem alone. The greater effect seen at the endplate implies that neuromuscular activity is an important factor. The drugs may be causing a reduction in alpha‐actinin labelling by different mechanisms.
Fasciitis, perimyositis, myositis, polymyositis, and eosinophilia
Authors: Serratrice G. , Pellissier J. F. , Roux H. , Quilichini P. 
Published: January 2005

AbstractSeveral groups of cases of fasciitis and myositis with eosinophilia are reported. The common features are inflammation into fascia and/or perimysium, and/or muscle fibers; eosinophilia in blood and/or in muscle biopsy. The following classification of 24 cases is suggested: at one end of the spectrum are fasciitis with eosinophilia: diffuse fasciitis (Shulman syndrome): 10 cases (3 with hematological complications); 2 cases of diffuse fasciitis with muscle atrophy; 3 cases of restricted fasciitis. Relapsing perimyositis with eosinophilia belong to the same spectrum, either diffuse (5 cases) with myalgias, or localized (2 cases). Other cases are focal myositis or multiple myositis, polymyositis with eosinophilia. The relationship among these cases is discussed. There is a continuum among the different groups. The pathophysiology remains unknown.
Growth and denervation response of skeletal muscle fibers of newborn rats
Authors: Schmalbruch Henning 
Published: January 2005

AbstractThe cross‐sectional area of the fibers of hindlimb muscles of rats increased 10–40 times during the first 6 weeks after birth. Denervation at birth stopped the growth of the muscle fibers. The number of satellite cells decreased, and eventually all fibers vanished. Reinnervation, if any, was poor. Partial denervation did not induce collateral reinnervation. Some denervated gastrocnemius muscles were reinnervated and after 8–12 months contained hypertrophic fibers and signs of necrosis and regeneration. When soleus muscles were completely denervated and cross‐reinnervated after 4 weeks by the peroneal nerve, only half as many fibers became reinnervated after neonatal denervation as compared to muscles denervated at the age of 4 weeks. The experiments suggest that immature muscle fibers are less apt to become reinnervated than mature fibers. The few reinnervated fibers may be overloaded and therefore hypertrophy and eventually necrotize. Regeneration is abortive because satellite cells are scarce. These results may be relevant for the understanding of neuromuscular disorders with early (fetal) onset.
Schwartz–Jampel syndrome: I. Clinical, electromyographic, and histologic studies
Authors: Spaans Frank , Theunissen Pierre , Reekers Ad , Smit Leo , Veldman Henk 
Published: January 2005

AbstractIn a new, typical case of Schwartz–Jampel syndrome (SJS) the origin of the disorder was found to be purely myogenic. Concentric needle EMG showed abundant and persistent spontaneous activity, maximal at insertion, and uninfluenced by local curarization. Single‐fiber EMG showed rather stable, sometimes intermittent, discharge series with occasional amplitude and/or frequency fluctuations. It could be demonstrated that this activity did not consist of complex repetitive discharges, but of independent activity of individual muscle fibers. This contrasts with findings by other investigators that have been published in this journal. 8, 17 Light microscopic studies of quadriceps and intercostal muscles showed no abnormalities, whereas electron‐microscopic findings were in accordance with earlier studies in SJS. Endplate analysis revealed no specific changes; the postsynaptic stectures gave the impression of an accelerated‐maturation.
AAEM minimonograph #34: Polyneuropathy: Classification by nerve conduction studies and electromyography
Authors: Donofrio Peter D. , Albers James W. 
Published: January 2005

AbstractElectrodiagnostic evaluation of patiets with suspected polyneuropathy is useful for detecting and documenting peripheral abnormalities, identifying the predominant pathophysiology, and determining the prognosis for certain disorders. The electrodiagnostic classification of polyneuropathy is associated with morphologic correlates and is based upon determining involvement of sensory and motor fibers and distinguishing between predominantly axon loss and demyelinating lesions. Accurate electrodiagnostic classification leads to a more focused and expedient identification of the etiology of polyneuropathy in clinical situations.
Isometric features of orthostatic tremor: An electromyographic analysis
Authors: Walker Francis O. , McCormick George M. , Hunt Vicki P. 
Published: January 2005

AbstractA patient is described with “orthostatic” tremor. Electromyography revealed tremor bursts of 15 Hz in the lower extremities while standing and with isometric activation of the muscles, but the bursts disappeared with isotonic activation of muscles. Similar tremor was recorded in the arms with isometric, but not isotonic activation. Review of previously reported cases confirms these findings. The clinical and electrophysiologic features of this tremor distinguish it from other recognized forms of tremor.
A tetrodotoxin‐ and Mn2+‐insensitive Na+ current in Duchenne muscular dystrophy
Authors: Bkaily Ghassan , Jasmin Gaétan , Tautu Constantin , Prochek Libuse , Yamamoto Tatsuo , Sculptoreanu Adrian , Peyrow Mehrzad , Jacques Danielle 
Published: January 2005

AbstractMuscle myotube cultures were obtained from normal and Duchenne muscular dystrophy (DMD) biopsies by using an explant technique. The currentvoltage (I/V) curve of the whole sodium (Na+) current (INa) in normal myotubes was similar to that obtained from DMD myotubes. However, the inactivation curve of the whole INa was different in normal myotubes when compared to that obtained from DMD myotubes. Addition of 10−4 tetrodotoxin (TTX, a fast INa blocker) decreased the whole INa in both preparations. The inorganic calcium (Ca2+) blocker manganese (Mn2+) completely blocked the remaining TTX‐resistant INa of normal myotubes and decreased this current in DMD myotubes leaving behind a TTX‐ and Mn2+ ‐insensitive INa that was insensitive to the Ca2+ blocker desmetoxyverapamil ((–)D888). The slow inward barium current (IBa) of both normal and DMD myotubes was blocked by Mn2+ and (–)D888. However the kinetics of the slow channel in normal myotubes was different from that of DMD myotubes. This study demonstrates the presence of a TTX‐ and Mn2+ ‐insensitive INa in DMD myotubes. This channel may contribute to the increase of intracellular Na+ ([Na]i) in DMD and allow Ca2+ to enter the cells through the Na+Ca2+ exchanger, thus contributing to calcium loading.
Quantitative electromyography in polymyositis: A reappraisal
Authors: Trojaborg Werner 
Published: January 2005

AbstractManual analysis of motor unit action potentials (MUAPs) was performed in 33 patients with polymyositis of whom 16 were studied in the acute stage and 17 in the chronic stage. Contrary to common description of “myopathic potentials” as being of low amplitude, short duration, and polyphasic shape, the quantitated study revealed no difference as to amplitude of short duration MUAPs in patients and normal subjects though short‐duration MUAP and short duration polyphasic potentials were 4 and 3 times, respectively, more common in patients than in controls. Although the mean duration of MUAPs usually was significantly shorter in polymyositis than in controls, the average scatter of MUAPs duration was the same in the 2 groups. The average incidence of polyphasic MUAPs was 4 times higher in patients than in controls, as was the incidence of those of long duration. To avoid misinterpretation of EMG findings due to an excess of polyphasic MUAPs, a greater number of individual potentials than usually recommended should be collected allowing a valid estimate of the mean duration of MUAPs of simple configuration.
A comparison of thermography and electromyography in the diagnosis of cervical radiculopathy
Authors: So Yuen T. , Olney Richard K. , Aminoff Michael J. 
Published: January 2005

AbstractWe studied 20 asymptomatic control subjects and 14 patients with clinically unequivocal cervical radiculopathy to compare the diagnostic value of thermography with that of electromyography. We measured the average skin temperature of designated regions over the neck, shoulder, and upper extremities. We then compared the temperature between corresponding regions of the two limbs, and between fingers innervated by different roots in the same hand. Thermography was abnormal in 6 patients (43%), whereas electromyography was abnormal in 10 (71%). Thermographic abnormalities were seen only in the hands and fingers, and the pattern did not follow the dermatome of the clinically involved cervical root. When compared to electromyography, thermography provided no additional diagnostic information. Thus, thermography does not have an established role in the evaluation of patients with cervical radiculopathy.
Twitch relaxation of the cat soleus muscle at different lengths and temperatures
Authors: Iaizzo Paul A. , Poppele Richard E. 
Published: January 2005

AbstractWe recorded isometric and isotonic twitches, in situ, from the cat soleus at various muscle lengths and temperatures. At a given temperature the duration of isometric twitches increased approximately 60% for each 10% increase in muscle length, which was primarily owing to decreases in the rate of relaxation. For the relaxation of isometric twitches recorded at different muscle lengths, the equivalent activation energies determined were the same (13.2 ± 0.3 kcal/M). The duration of isotonic twitch contractions increased only 20% for each 10% increase in muscle length. Even a small amount of shortening (3%) diminished the dependence of twitch duration on muscle length. In this case, twitch duration increased approximately 30% for every 10% increase in muscle length. Hence, even small changes in internal and/or external compliance (eg, changes in the tendon‐fiber continuity) can greatly influence twitch duration. Our findings are consistent with the hypotheses that in the cat soleus, Ca2+ sequestration is primarily governed by a single energy dependent process and that the Ca2+ sensitivity of the contractile apparatus increases with increasing sarcomere length.
Motor unit spike counts before and after maximal voluntary contraction
Authors: Gooch Judith L. , Newton Bruce Y. , Petajan Jack H. 
Published: January 2005

AbstractMotor unit spike counts in the biceps brachii muscle were evaluated using a monopolar needle electrode during maintenance of antigravity posture with the elbow flexed to 45° before and after maximal voluntary contraction (MVC). After MVC, the number of motor unit spikes/second needed to maintain this posture was about 50% less than prior to MVC. Surface rectified integrated EMG activity declined in parallel to the decline in spike counts. To determine whether different muscles were compensating for the reduction in spike counts, synergistic muscles were examined simultaneously. Similar reductions were noted. In one deafferented subject, EMG activity increased rather than decreased after MVC. Fatigue decreases the contraction–relaxation rate of muscle fibers, which lowers fusion frequency. Thus, lower rates of motor unit activiation can result in the maintenance of constant force. A feedback system from muscle to CNS likely senses this slowing and leads to the spike count reduction.
Randomized, double‐blind trial of mazindol in Duchenne dystrophy
Authors: Griggs Robert C. , Moxley Richard T. , Mendell Jerry R. , Fenichel Gerald M. , Brooke Michael H. , Miller Phillip J. , Mandel Stephen , Florence Juliane , Schierbecker Janine , Kaiser Kenneth K. , King Wendy , Pandya Shree , Robison Jenny , Signore Linda 
Published: January 2005

AbstractThere is evidence that growth hormone may be related to the progression of weakness in Duchenne dystrophy. We conducted a 12‐month controlled trial of mazindol, a putative growth hormone secretion inhibitor, in 83 boys with Duchenne dystrophy. Muscle strength, contractures, functional ability and pulmonary function were tested at baseline, and 6 and 12 months after treatment with mazindol (3 mg/d) or placebo. The study was designed to have a power of >0.90 to detect a slowing to 25% of the expected rate of progression of weakness at P < 0.05. Mazindol did not benefit strength at any point in the study. Side effects attributable to mazindol included decreased appetite (36%), dry mouth (10%), behavioral change (22%), and gastrointestinal symptoms (18%); mazindol dosage was reduced in 43% of patients. The effect of mazindol on GH secretion was estimated indirectly by comparing the postabsorptive IGF‐I levels obtained following 3, 6, 9, and 12 months in the mazindol treated to those in the placebo groups. Although mazindol‐treated patients gained less weight and height than placebotreated patients, no significant effect on IGF‐I levels was observed. Mazindol does not slow the progression of weakness in Duchenne dystrophy.