bluuebunny/crossref_metadata_2025 huggingface dataset:
The clinical and diagnostic role of anti‐GM1 antibody testing
Authors: Kornberg Andrew J. , Pestronk Alan
Published: January 2005

There is increasing evidence that multifocal motor neuropathy (MMN) and some lower motor neuron (LMN) syndromes are immune‐mediated and treatable. The frequent occurrence of high titers of anti‐GM1 antibodies in these motor neuropathies raised hopes that serum testing would provide useful diagnostic information. Unfortunately, in routine practice, simple quantification of IgM binding to GM1 ganglioside has proved to be a test with poor sensitivity and specificity. We have found that much greater sensitivity and specificity for MMN and LMN syndromes can be obtained by determining serum antibody binding to panels of antigens, such as GM1, histone H3, and NP‐9. These results suggest that combined measurement of serum antibody binding to GM1 and other antigens can provide tests that are useful in the diagnosis and management of motor neuropathy syndromes. © 1994 John Wiley & Sons, Inc.
Single fiber EMG and repetitive stimulation of the same muscle in myasthenia gravis
Authors: Gilchrist James M. , Massey Janice M. , Sanders Donald B.
Published: January 2005

We performed RNS and SFEMG studies of the same muscle in 46 patients with myasthenia gravis. Maximum decrement to 3–5‐Hz stimulation before and after maximum voluntary exercise, percentage of action potential pairs with increased jitter and blocking, and mean MCD in each study were compared. A significant decrement (> 10% decrease in CMAP area or amplitude between the first and fourth response) was never found without increased jitter and impulse blocking on SFEMG. Increased jitter, blocking, and mean MCD were each correlated with maximum decrement (r > 0.61, P < 0.0001). We conclude that decrement to RNS and impulse blocking on SFEMG result from the same physiologic phenomenon, and that SFEMG is more sensitive at detecting disordered neuromuscular transmission given its ability to detect impulse blocking at levels below the resolution of RNS and increased neuromuscular jitter when there is not blocking. © 1994 John Wiley & Sons, Inc.
Multifocal motor neuropathy: Electrodiagnostic features
Authors: Chaudhry Vinay , Corse Andrea M. , Cornblath David R. , Kuncl Ralph W. , Freimer Miriam L. , Griffin John W.
Published: January 2005

Diagnosis of multifocal motor neuropathy (MMN), a syndrome characterized by progressive asymmetric weakness with intact sensation, is important because the disorder often responds to treatment. Multifocal partial motor conduction block (PMCB) has been emphasized as a cardinal feature in the diagnosis of this syndrome, but detailed nerve conduction studies are not available. Nine patients, ages 28–58, had chronic, progressive, asymmetric, predominantly distal limb weakness for 5–18 years. Sensation was normal and reflexes were reduced asymmetrically. Although all 9 demonstrated PMCB localized to short nerve segments, additional features of multifocal motor demyelination were present, including temporal dispersion (5 patients), segmentally reduced motor nerve conduction velocity (7 patients), prolonged distal motor latency (4 patients), and prolonged F‐wave latency (9 patients). The strength of all patients improved after treatment with human immune globulin. A reduction in the degree of PMCB or an increase in the distal motor amplitude or both accompanied the clinical improvement. These studies suggest that patients with MMN demonstrate widespread evidence of motor demyelination in addition to the well‐described PMCB, and that reduction of PMCB accounts for the increase in strength following therapy. © 1994 John Wiley & Sons, Inc.
X‐linked bulbospinomuscular atrophy (Kennedy's disease) masquerading as lead neuropathy
Authors: Albers James W. , Bromberg Mark B.
Published: January 2005

A 43‐year‐old male was referred by a veterinarian who evaluated his dog for a seizure and suspected a toxic lead exposure for both. He refurbished houses, removing old paint, and complained of decreased cognition, fatigue, and muscle cramps. He had a depressed affect, postural tremor, right arm weakness with partial denervation on EMG, and borderline‐low sensory nerve action potential (SNAP) amplitudes. A mild anemia and elevated serum and urine lead levels supported a diagnosis of lead neuropathy. Chelation therapy increased urine lead excretion without symptomatic improvement. His brother worked part‐time with him and developed similar findings, but also had difficulty chewing, dysphagia, perioral twitching, gynecomastia, and multifocal denervation of extremity and facial muscles. His lead levels were not elevated, but an androgen receptor mutation identified on the X chromosome for both brothers confirmed the diagnosis of X‐linked bulbospinomuscular atrophy (Kennedy's disease). © 1994 John Wiley & Sons, Inc.
Electromyography and biopsy correlation with suggested protocol for evaluation of the floppy infant
Authors: David William S. , Jones H. Royden
Published: January 2005

Eighty infants with nonarthrogrypotic floppy infant syndrome (FIS) were evaluated between 1979 and 1990. Electromyographic data were correlated with results of muscle and nerve biopsies in 41 of 80 who had concomitant biopsies (38) or other diagnostic analyses (3). A diagnosis was made of Werdnig–Hoffmann disease (WHD) in 15, a congenital infantile polyneuropathy (IPN) in 3, neuromuscular transmission defect (NMTD) in 2, myopathy in 12, and presumed “central” hypotonia in 9. A very positive correlation rate between nerve conduction studies with electromyography and biopsy results was found in 93% (14 of 15) with WHD and 100% in IPN (3 of 3). However, only 4 of 10 infants (40%) with biopsy‐proven myopathy had an abnormal EMG. Only once did the results of electromyography and biopsy conflict. © 1994 John Wiley & Sons, Inc.
Motor unit territory in relation to tendons in the human masseter muscle
Authors: Tonndorf Mônica L. , Hannam Alan G.
Published: January 2005

In the human masseter, motor‐unit (MU) territories are reportedly focal and it is possible that they are confined to the muscle's internal aponeuroses. However, previous electromyographic (EMG) investigations of MU sizes have not correlated them with the muscle's internal architecture. In this study, 162 single‐MU territories were assessed by scanning EMG recordings throughout the masseter muscles of 4 subjects. The needle‐electrode scans were stereotactically located with magnetic resonance imaging and an optical system capable of tracking the needle movement in three dimensions. Mediolateral territorial dimensions were then displayed graphically within muscle reconstructions. The mean territorial width was 3.7 ± 2.3 mm and varied between 0.4 and 13.1 mm. The widths were comparable in size to those of previous reports, and were related to the subject's muscle size. Most MU territories were confined, and lay between tendons, although 10% of the units clearly extended across at least one tendon. The dispersion of most territories within discrete tendon‐bounded compartments in the masseter provides an anatomical basis for selective activation of the muscle. However, it is also possible that this arrangement provides a flexible means for ensuring tendon stiffness and mechanical adaptation of the multipennate masseter during growth and development, whether or not the muscle is activated selectively. © 1994 John Wiley & Sons, Inc.
Temperature dependence of nerve conduction and EMG in neuropathy associated with gammopathy
Authors: Notermans Nicolette C. , Franssen Hessel , Wieneke George H. , Wokke John H. J.
Published: January 2005

The effects of warming on nerve conduction variables and electromyography were studied in 15 patients with a polyneuropathy associated with monoclonal gammopathy of undetermined significance. In each patient median nerve (motor, sensory) and tibial nerve (motor) conduction parameters were measured before and after warming in water at 36°C. Warming: (1) increased the conduction velocity (CV); (2) decreased the distal motor latency, amplitude, and duration of the corn f pound muscle or nerve action potential; and (3) caused fibrillations to appear in 1 patient. The increase in CV with temperature depended upon the CV after warming: the lower this CV, the smaller the increase in CV with temperature (ΔCV/Δ). Correction of median nerve motor CV before warming with 2.2 m/s per °C yielded CV values which were higher than the CV values after warming, because in most patients ΔCV/Δ was less than 2.2 m/s per °C. Because of differences in ΔCV/Δ values, it is more accurate to warm the extremity than to correct for temperature. © 1994 John & Sons, Inc.
Immunocytochemistry of muscle cytoskeletal proteins in acid maltase deficiency
Authors: Vita Giuseppe , Migliorato Alba , Toscano Antonio , Bordoni Andreina , Bresolin Nereo , Fiumara Agata , Messina Corrado
Published: January 2005

Immunocytochemistry of dystrophin, spectrin, vinculin (sarcolemmaspecific proteins), and desmin (an intermediate filament protein) were investigated in 5 patients with acid maltase deficiency (AMD). One patient had infant onset, 2 had childhood onset, and 2 had adult onset. All had a vacuolar myopathy with autophagic vacuoles containing glycogen and cytoplasmic degradation products. Dystrophin, spectrin, and vinculin were localized at the sarcolemma as in normal muscle fibers. Within the cytoplasm of many fibers, immunoreactivity for the three proteins was seen as single or multiple spots or as circular structures, which most likely corresponded to the limiting membrane of vacuoles. Desmin was overexpressed at the periphery of some vacuoles. It is plausible that, before exocytosis occurs, sarcolemma‐specific proteins appear within the vacuole membrane. Vacuole immunolabeling frequently occurred in the patients with childhood and adult onset AMD, but very rarely occurred in the case with infant onset. We hypothesize that a reduced exocytosis rate might explain the infrequent vacuole immunolabeling and the early onset of the infant form of the disease. © 1994 John Wiley & Sons, Inc.
Axonal Guillain–Barré syndrome
Authors: Feasby Thomas E.
Published: January 2005

The issue of “axonal” Guillain–Barré syndrome (GBS) remains controversial. Supportive evidence comes from pathological examination of peripheral nerves in 4 extreme cases of GBS 17–29 days after onset which showed severe axonal degeneration without inflammatory‐demyelination. It has been suggested that inflammatory‐demyelination may have been missed. This is difficult to disprove but it seems unlikely, given the known correlation between the severity of axonal degeneration and inflammation/demyelination in the experimental model of GBS, experimental allergic neuritis (EAN). Electrically inexcitable nerves in GBS may reflect axonal degeneration, terminal demyelination or both. This finding proved to be a sign of poor prognosis in 19 of 27 (70%) patients, although a good outcome occurred in some cases. © 1994 John Wiley & Sons, Inc.
Central fatigue as revealed by postexercise decrement of motor evoked potentials
Authors: Brasil‐Neto Joaquim P. , Cohen Leonardo G. , Hallett Mark
Published: January 2005

We have previously shown that the amplitudes of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) were transiently decreased after exercise, indicating fatigue of motor pathways in the central nervous system. The responsible mechanism is apparently decreased efficiency in the generation of the descending volleys in the motor cortex. We also noted a progressive decrement inamplitude from the first to the fourth MEP. To further clarify the mechanism of this phenomenon, 5 subjects were studied with TMS deliveredat the rates of 0.1, 0.15, 0.3, 1, 3, and 6 Hz. The effect was best demonstrated at 0.3 Hz, and occurred after both isometric and isotonic exercise. Three of the subjects also had 0.3‐Hz percutaneous electrical stimulation of the brainstem, and a decrement in MEP amplitude did not occur. Further, the delivery of TMS during muscle contraction after muscle fatigue failed to produce a decrement. The results are similar to those found at the neuromuscular junction in myasthenia gravis and are consistent with a reduced safety factor of cortical synaptic transmission in central nervous system fatigue. © 1994 John Wiley & Sons, Inc.
Acute postasthmatic amyotrophy (Hopkins' syndrome)
Authors: Liedholm Laps Johan A. , Eeg‐Olofsson Orvar , Ekenberg B. Ewa K. , Nicolaysen Randi Beck , Torbergsen Torberg
Published: January 2005

Acute postasthmatic amyotrophy is a rare condition, previously reported in only 26 cases. It is characterized by a sudden onset of a flaccid paralysis of an arm or a leg with completely preserved sensibility, about 1 week after an asthmatic attack. The cause is probably due to a lesion of the anterior horn of the spinal cord, but evidence indicates a more widespread pathological process. The etiology is unknown. but infectious or immunological mechanisms are likely. © 1994 John Wiley & Sons, Inc.
Sensory and mixed nerve conduction studies in the evaluation of ulnar neuropathy at the elbow
Authors: Raynor Elizabeth M. , Shefner Jeremy M. , Preston David C. , Logician Eric L.
Published: January 2005

The relative sensitivities of sensory, mixed nerve, and motor conduction studies in assessing ulnar neuropathy at the elbow have not yet been established. Using surface electrodes, we performed conduction studies across the elbow segment in 43 patients with symptoms referable to the ulnar nerve and 40 control subjects. Segmental slowing of motor conduction localized the lesion to the elbow in 14 of 21 patients (67%) with clear evidence of ulnar neuropathy on physical examination but only in 2 of 22 (9%) with subtle or no physical examination abnormalities. The diagnostic yield was increased by the finding of segmental slowing of sensory or mixed nerve conduction across the elbow to 86% and 68%, respectively, for each of the groups. We conclude that surface‐recorded sensory and mixed nerve conduction studies appear to be more sensitive than motor studies in the electrodiagnosis of ulnar neuropathy at the elbow and are especially valuable in patients with subtle clinical involvement. © 1994 John Wiley & Sons, Inc.
Acute peripheral neuropathy due to hereditary coproporphyria
Authors: Barohn Richard J. , Sanchez Jose A. , Anderson Karl E.
Published: January 2005

A 23‐year‐old man with epilepsy and a past history of abdominal pain and ileus, developed hypertension and arm and bulbar weakness when valproic acid and carbarnazepine were reinitiated. Electrophysiologic studies demonstrated a peripheral neuropathy with features of axonal degeneration and demyelination. Axonal degeneration was documented by sural nerve biopsy. Markedly elevated urinary 8‐aminolevulinic acid and porphobilinogen indicated a diagnosis of acute porphyria. Other laboratory studies were most consistent with hereditary coproporphyria. Motor function improved considerably but incompletely over 1 year. An acute, primarily motor neuropathy can occur in several forms of porphyria, including acute intermittent porphyria, variegate porphyria, and hereditary coproporphyria, sometimes even in the absence of concomitant gastrointestinal symptoms. © 1994 John Wiley & Sons, Inc.
Computational methods for improving estimates of motor unit twitch contraction properties
Authors: Lim K. Y. , Rymer W. Z. , Thomas C. K.
Published: January 2005

Estimates of mechanical properties of human motor units have usually been made indirectly, using the technique of “spike‐triggered averaging” (STA). In this method, a single motor unit action potential is used to synchronize the accumulation of an ensemble average of correlated force transients. However, under most realizable conditions, these transients are recorded during periods of sustained motor unit discharge, in which each motor unit is producing a partially fused tetanus. Therefore, the STA technique extracts the characteristics of the unfused force transient, instead of the desired single motor unit twitch. Although the STA method has been widely used, there is as yet no wellestablished relation between the force transient in the unfused tetanus, and the twitch contraction properties of the motor unit. To evaluate the accuracy of the STA as a measure of the motor unit mechanical properties, we applied two types of muscle models to the force transients recorded in an unfused tetanus, using data derived from experiments in which the response to a single twitch was also recorded. Our objective was to see whether accurate predictions of single motor unit mechanical characteristics are possible, working backward from the STA. The models chosen for this task were a linear second order model, and the distribution‐moment (DM) model. These model predictions were then compared with the STA response, and with the twitch properties of the individual motor units. We also evaluated the utility of extrapolating the initial slope of the STA backward to improve the accuracy of the mechanical estimates. The results of our simulation suggest that there is no straightforward relation bwtween the characteristics of the unfused tetanus and the mechanical properties of the single twitch. Although our attempts to predict the properties of the single twitch from the STA were only partly successful, the results of the simulations were far more accurate than those derived from the STA alone. Because the errors in the use of the STA method were so substantial, we would urge that the STA technique be used with great caution as a measure of twitch contraction properties, unless accompanied by appropriate simulations of muscle mechanical behavior.© 1995 John Wiley &Sons, Inc.
Multiple innervation of muscle fibers in myasthenia gravis
Authors: Trontelj Jožze V. , Stålberg Erik V.
Published: January 2005

Single fiber EMG recordings from patients with myasthenia gravis obtained during axonal microstimulation revealed an occasional bimodal distribution of response latencies. This phenomenon could be dependent on stimulus strength, however, in a way different from that in the axon reflex. It is suggested to be due to dual neuromuscular junctions (NMJs) supplied by two different motor neurons. Some cases of bimodal jitter were not dependent on stimulus strength and are assumed to be due to dual innervation by the same neuron. The phenomenon could only be demonstrated at abnormal NMJs with partial impulse blocking. It is suggested to reflect multiple reinnervation of muscle fibers that had undergone functional or structural denervation in the course of the immune attack against the original NMJ. This study suggests that the coexisting NMJs from the same or different motor neurons may be functional at the same time.© 1995 John Wiley &Sons, Inc.
Comparison of the flexed and extended elbow positions in localiziing ulnar neuropathy at the elbow
Authors: Kothari M. J. , Preston D. C.
Published: January 2005

Electrophysiologic localization of ulnar neuropathy at the elbow often depends on demonstration of segmental slowing. Based on normative data obtained from 50 control subject, we compared the utility of flexed and extended elbow positions in demonstrating focal slowing at the elbow as compared to the forearm segment in patients with ulnar neuropathy. We studied 35 patients with ulnar neuropathy with definite electrophysiologic localization to the elbow segment defined by conduction block across the elbow segment or by focal slowing demonstrated either in the flexed or extended position. Applying cutoff values from the control group, all 35 patients demonstrated focal slowing at the elbow in the flexed position, whereas only 5 of 35 (14%) patients did so in the extended position. We Conclude that the flexed elbow position is more sensitive than the extended position in localizing ulnar neuropathy at the elbow and should be the preferred method when performing ulnar motor conduction studies.© 1995 John Wiley &Sons, Inc.
Transcranial magnetic stimulation of the trigeminal nerve: Intraoperative study on stimulation characteristics in man
Authors: Schmid Urs D. , Møller Aage R. , Schmid Judith
Published: January 2005

We studied responses from the masseter and nasalis muscles following magnetic stimulation (magStim) and compared these responses with those obtained by direct electrical stimulation of the trigeminal (NV) and facial (NVII) nerve near the root exit zone during microvascular decompression operations of NVII. We found that (1) magStim threshold to excite the nerve is high for NV and low for NVII; (2) excitation of all motor fibers is impossible for NV, and easy for NVII; (3) optimal coil placement is critical for NV, but not critical for NVII; and (4) between and within subjects, the excitation site is variable on NV, but stable on NVII. We estimated that the anatomical location of magStim to be either within or outside the cerebrospinal fluid for NV, and to be in the labyrinthine segment of the facial canal for NVII. Physical models explain and clinical lesion models support these differences found between NV and NVII. © 1995 John Wiley & Sons, Inc.
Case of the month. Disseminated histoplasmosis presenting as myositis and fasciitis in a patient with dermatomyositis
Authors: Voloshin Denise K. , Lacomis David , McMahon Deborah
Published: January 2005

A 54‐year‐old man with dermatomyositis initially responsive to corticosteroids and methotrexate developed severe myalgias, increasing weakness, and fevers. Laboratory studies were suggestive of disseminated histoplasmosis, and muscle biopsy revealed myositis, fasciitis, and yeast in the perimysial connective tissue. Histoplasma capsulatum was cultured from skeletal muscle. Despite antifungal therapy, necrotizing fasciitis progressed to gluteal abscess formation. Disseminated histoplasmosis may present atypically in immunocompromised hosts as fasciitis and myositis. Patients with dermatomyositis could be particularly vulnerable to soft tissue invasion by fungi due to their underlying microangiopathy. © 1995 John Wiley & Sons, Inc.
Reliability of measurements of muscle strength and voluntary activation using twitch interpolation
Authors: Allen G. M. , Gandevia S. C. , McKenzie D. K.
Published: January 2005

We investigated the reproducibility of measurements of maximal voluntary torque and maximal voluntary activation using twitch interpolation. On 5 days, each of 5 subjects performed 10 maximal voluntary isometric contractions of their elbow flexors. Single supramaximal stimuli were delivered over biceps brachii at the measured peak torque during each effort, and in the relaxed muscle 5 s later. A voluntary activation score was calculated from the size of twitches evoked by the stimuli (resolution < 0.15 Nm). Although all subjects were able to drive the stimulated elbow flexor muscles maximally in some trials, they did not do so in 75% of all contractions. Maximal voluntary torques did not vary significantly within a subject between sessions. There were consistent differences in the level of maximal voluntary activation between subjects (P < 0.01), but no differences in voluntary activation within an individual across days in 4 of 5 subjects. Failure to drive the stimulated elbow flexor muscles maximally was not associated with inadvertent co‐contraction of the antagonist muscles. © 1995 John Wiley & Sons, Inc.
Neuromuscular disorders in systemic malignancy and its treatment
Authors: Stübgen Joerg‐Patrick
Published: January 2005

Neuromuscular dysfunction in patients with known or suspected malignancy has three basic etiologies: (1) a direct effect of the neoplasm, either by compression or infiltration; (2) a “remote,” or paraneoplastic, effect of cancer; or (3) a side effect of anticancer treatment, radiation or chemotherapy. A variety of clinical features or syndromes are due to damage either at the level of the neuron (anterior horn cell or dorsal root ganglion neuron), nerve root(S), brachial or lumbosacral plexus, peripheral nerve (motor, sensory, and/or autonomic), neuromuscular junction, or muscle. A complex clinical picture evolves when dysfunction in due to more than one cause at more than one anatomical site. © 1995 John Wiley & Sons, Inc.
Dynamical analysis of neuromuscular transmission jitter
Authors: Gilchrist James M. , Perrone Michael , Ross John
Published: January 2005

Utilizing prolonged axonal stimulation single fiber EMG, neuromuscular transmission becomes a time‐series of interpotential intervals (IPIs). In this form, the underlying processes of neuromuscular transmission can be studied using standard numerical techniques to determine whether these processes can be described by a simple mathematical model. In particular, neuromuscular transmission jitter can be examined in this way. In this article, we attempt to determine whether healthy jitter is noise or deterministic chaos. The presence of deterministic chaos was assessed by analysis of the IPI time‐series using visual inspection of both phase‐space plots and their principal component dimensions, and using the Grassberger–Procaccia algorithm to determine the correlation dimension of the time‐series dynamics. These graphical and mathematical techniques provided little evidence for the existence of deterministic chaos. Linear autoregression time‐series prediction also failed to account for the variability of the data and IPI histograms exhibited simple gaussian distributions. These results suggest normal neuromuscular transmission jitter is the result of intrinsic noise. © 1995 John Wiley & Sons, Inc.
Characterization of the glycolysis in lactate dehydrogenase‐A deficiency
Authors: Miyajima Hiroaki , Takahashi Yoshitomo , Kaneko Eizo
Published: January 2005

Recurrent rhabdomyolysis due to decreased glycolysis occurred during strenuous exercise by patients with lactate dehydrogenase‐A subunit (LDH‐A; muscle) deficiency. We report the glycolytic features of 4 patients from 2 families in whom the severity of the disease differed. There was no difference in the gene abnormality. The enzyme activity of LDH in the muscle was less than 5% that of the control value. Glycolysis in the muscle showed that the respective sums of the pyruvate and lactate levels in the patients with mild and severe symptoms were reduced to approximately 65% and 35% that of the control value. Comparable amounts of glycerol 3‐phosphate were produced. Glycerol 3‐phosphate dehydrogenase activity in the muscles of patients with mild symptoms was three times the control value. These findings suggest that the disease severity in our patients may be related to the degree of NADH reoxidation by glycerol 3‐phosphate dehydrogenase substituting for LDH. © 1995 John Wiley & Sons, Inc.
Number and relative size of thenar motor units estimated by an adapted multiple point stimulation method
Authors: Wang François‐Charles , Delwaide Paul J.
Published: January 2005

An adapted multiple point stimulation (AMPS) method is described for estimating the number and relative size of thenar motor units. With this method, the median nerve was stimulated at various sites from the wrist to the elbow. To avoid alternation, only two or three clearly identifiable surface‐recorded motor unit action potentials (S‐MUAPs) were recruited at each point by incremental stimulation. A total of 10 S‐MUAPs, eleicited from four to five distinct stimulatin points, was used to calculate the average S‐MUAP size. By dividing the maximum M‐potential size by that value, a motor unit number estimate (MUNE) was derived. In 59 healthy volunteers, from 19 to 87 years old, the mean average S‐MUAP size was 87 ± 27.6 μV. ms and the mean MUNE was 278 ± 113 motor units. When performed repeatedly, the results were reproducible. The number of motor units declined exponenetially with age while average S‐MUAP sized increased only moderately. To assess the validity of the AMPS method, its results were correlated with those obtained using the F‐response technique. The correlation coefficient was 0.83 (P < 0.001). © 1995 John Wiley & Sons, Inc.
Increased laminin a expression in regenerating myofibers neuromuscular disorders
Authors: Mundegar Rustam R. , Von Oertzen Joachim , Zierz Stephan
Published: January 2005

Laminin is a basement membrane (BM) glycoprotein composed of three of five subunits, the A, M, B1, B2, and the S chain. Four forms of laminin, A‐B1‐B2, A‐S‐B2, M‐B1‐B2, and M‐S‐B2, have been identified. Laminin is implicated in various biological processes such as cell adhesion and differentiation. We studied immunohistochemically the expression of the four laminin subunits A, M, B1, B2 as well as of neural cell adhesion molecule (N‐CAM, CD56), a marker of regenerating myofibers, in various neuromuscular disorders. In normal muscle, the predominant subunits of myofiber laminin were M, B1, and B2. The A chain was only faintly expressed in myofiber BM. In inflammatory myopathies and dystrophinopathies myofiber laminin A expression was greatly increased. An average of 80% and 63% of laminin A–positive myofibers in inflammatory myopathies and dystrophinopathies, respectively, were additionally CD56 positive. Laminin A and CD56 expression in denervating diseases and mitochondrial myopathies were negligible. Expression of M, B1, and B2 subunits did not seem to be altered in the diseased conditions examined above. The data suggest that laminin A is upregulated in inflammatory myopathies and dystrophinopathies and, most markedly in regenerating myofibers. © 1995 John Wiley & Sons, Inc.
Regeneration across preserved peripheral nerve grafts
Authors: Evans Peter J. , Mackinnon Susan E. , Best Timothy J. , Wade Judith A. , Awerbuck David C. , Makino Akira P. , Hunter Daniel A. , Midha Rajiv
Published: January 2005

The potential to store nerve grafts for a prolonged period of time was assessed in a rat sciatic nerve model. Three‐centimeter syngeneic nerve grafts were stored in Belzer/University of Wisconsin cold storage solution at different temperatures (5°C, 22°C, or 37°C) for varying time periods (6 h, 24 h, or 3 weeks) prior to transplantation. Functional assessment using serial walking track analyses revealed no difference between storage times and temperatures. At 14 months postengraftment, the conduction velocities and the number of myelinated fibers that had regenerated across all grafts stored at 5°C for all time periods tested were superior to grafts stored at either 22°C or 37°C. Nerve grafts stored for up to 3 weeks at 5°C acted as effective conduits for proximal regenerating fibers and resulted in histologic, electrophysiologic, and functional results equivalent to fresh nerve grafts. Nerve graft storage may be applicable to nerve allografts and potentially provide allograft material that requires reduced or no associated host immunosuppression.© 1995 John Wiley & Sons, Inc.
Multi‐motor unit action potential analysis (MMA)
Authors: Nandedkar Sanjeev D. , Barkhaus Paul E. , Charles Alison
Published: January 2005

We have developed an algorithm, called multi–motor unit action potential analysis (MMA), to aid quantification in routine needle EMG examination. In only 5–8 min, it was possible to extract, analyze, and validate 20 motor unit action potentials (MUAPs). In the biceps muscle of normal subjects, the MUAP measurements are compared with measurements using manual, triggered averaging, automatic decomposition, and other MMA algorithms described in the literature. The mean values of MUAP features by MMA fell between the extreme limits obtained from the amplitude‐triggered method and the manual method described in the literature. In patients, the results are consistent with routine EMG and similar to those results described in the literature. Fast acquisition and analysis of MUAPs as well as interference pattern (IP) analysis make this technique useful to document EMG abnormalities in routine needle examination.© 1995 John Wiley & Sons, Inc.
The relation between conduction velocity and axonal length
Authors: Zwarts Machiel J. , Guechev Antonin
Published: January 2005

Motor evoked potentials (MEPs) obtained by electrical root stimulation and F waves were used to examine the proximal nerve conduction velocity (CV) to tibialis anterior (TA), extensor digitorum brevis (EDB), flexor carpi radialis (FCR), and abductor pollicis brevis (APB) muscles in 40 humans. By subtracting motor latencies obtained by stimulating the peripheral nerve at the same point from the F‐wave and MEP latencies, we could measure the CV over identical proximal segments. It was found that proximal CV to TA and FCR was significantly higher than to EDB and APB, respectively. Combining the data of the proximal CV to all four muscles in relation with axonal length resulted in a highly significant inverse relationship (r2 = 0.77). Thus the axonal length explained to a large extent the higher CV of the arm nerves and also the inverse relation between body height and CV. The distal CV was always lower than proximal CV; however, there was no support for an additional effect of this gradient in explaining the relationship between CV and height since it was constant for all body heights. © John Wiley & Sons, Inc.
Superoxide dismutases of muscle in mitochondrial encephalomyopathies
Authors: Ohkoshi Norio , Mizusawa Hldehlro , Shiraiwa Nobuko , Shoji Shin'Ichi , Harada Katsutoshi , Yoshizawa Kazuo
Published: January 2005

Lmmunohistochemical analyses were made of the superoxide dismutases (Mn‐SOD and CuiZn‐SOD) in biopsied muscles from 7 patients with mitochondrial encephalomyopathies that included mitochondrial encephalomyopathy, lactic acidosis and strokelike episodes (MELAS), and chronic progressive external ophthalmoplegia (CPEO). Mn‐SOD mainly was present in the subsarcolemmal region, but it also was found in a coarsely granular, reticular, or diffuse pattern of staining within the muscle fibers. These Mn‐SOD‐positive fibers corresponded almost completely to the ragged‐red fibers. The immunoreaction for CuiZn‐SOD was weakly positive in some of the muscle fibers positive for Mn‐SOD. In CPEO, Mn‐SOD‐positive fibers predominantly showed decreased cytochrome c oxidase (COX) activity. In MELAS, Mn‐SOD‐positive fibers tended to be stained deeply for COX although a few were COX‐negative. These findings suggest that Mn‐SOD‐positive fibers can be used to make a differential diagnosis between CPEO and MELAS and that in mitochondrial encephalomyopathies Mn‐SOD in the raggedred fibers may protect against oxidative stress. © John Wiley & Sons, Inc.
Evidence of an abnormal intramuscular component of fatigue in multiple sclerosis
Authors: Sharma Khema R. , Kent‐Braun Jane , Mynhier Mark A. , Weiner Michael W. , Miller Robert G.
Published: January 2005

The goals of this study were to investigate muscle fatigue in patients with multiple sclerosis (MS), and to determine the relationships between muscle fatigue, clinical status, and perceived fatigue. The fatigability of the anterior tibial muscle was quantitated in patients and controls during 9 min of intermittent stimulation (used to eliminate central sources of muscle fatigue). During exercise, the decline in tetanic force, phosphocreatine, and intracellular pH was greater in patients than in controls. The compound muscle action potential amplitude did not decrease during exercise, indicating that there was no failure of neuromuscular transmission during fatigue. Thus, the excessive fatigue in MS developed from sources beyond the muscle membrane. Following exercise, the recovery of tetanic force was delayed in patients (a pattern that suggests abnormal excitation–contraction coupling), whereas the recovery of metabolites was complete in both groups. Muscular fatigue was correlated with clinical disability but not with perceived fatigue. These results suggests that fatigue in MS has both central (perception, upper motor neuron dysfunction) and peripheral (impaired metabolism and excitation–contraction coupling) components.© 1995 John Wiley &Sons, Inc.
Spinal motor neuron excitability during the cutaneous silent period
Authors: Leis A. Arturo , Štětkářová Ivana , Berić Aleksandar , Stokić Dobrivoje S.
Published: January 2005

The physiologic mechanisms generating the cutaneous silent period (CSP) remain uncertain. It is not known whether the CSP occurs because of inexcitability of the spinal motor neuron. We, therefore, assessed excitability of the motor neuron during the CSP using F‐wave responses. H‐reflexes were also elicited during the CSP. Electrical stimulation to the fifth digit produced the CSP in the voluntarily contracting abductor pollicis brevis muscle (APB). Median nerve stimulation at the wrist elicited control F or H responses during isometric APB contraction (condition 1) and in resting muscle (condition 2). Control amplitudes were compared to those elicited in the midst of the CSP. In Condition 1, F‐wave amplitudes and frequency during the CSP were unchanged compared with controls. However, F‐waves were increased in amplitude and frequency during the CSP (P < 0.001) relative to responses elicited in resting muscle (condition 2). H‐reflexes during the CSP were suppressed (P < 0.001) compared with controls elicited during contraction (condition 1), but facilitated relative to the resting state (condition 2) in which no H‐reflexes were elicitable. We conclude that spinal motor neurons remain excitable to antidromic volleys at the same time that the corticospinal volley is inhibited to produce the CSP. Moreover, motor neuron excitability appears to be increased during the CSP compared to the relaxed state. © 1995 John Wiley & Sons, Inc.
Applications of manganese‐enhanced magnetic resonance imaging (MEMRI) to image brain plasticity in song birds
Authors: Van der Linden Annemie , Van Meir Vincent , Tindemans Ilse , Verhoye Marleen , Balthazart Jacques
Published: January 2005

The song control system of song birds is an excellent model for studying brain plasticity and has thus far been extensively analyzed by histological and electrophysiological methods. However, these approaches do not provide a global view of the brain and/or do not allow repeated measures, which are necessary to establish correlations between alterations in neural substrate and behavior. Application of in vivo manganese‐enhanced MRI enabled us for the first time to visualize the song control system repeatedly in the same bird, making it possible to quantify dynamically the volume changes in this circuit as a function of seasonal and hormonal influences. In this review, we introduce and explore the song control system of song birds as a natural model for brain plasticity to validate a new cutting edge technique, which we called ‘repeated dynamic manganese enhanced MRI’ or D‐MEMRI. This technique is based on the use of implanted permanent cannulae—for accurate repeated manganese injections in a defined target area—and the subsequent MRI acquisition of the dynamics of the accumulation of manganese in projection brain targets. A compilation of the D‐MEMRI data obtained thus far in this system demonstrates the usefulness of this new method for studying brain plasticity. In particular it is shown to be a perfect tool for long‐term studies of morphological and functional responses of specific brain circuits to changes in endocrine conditions. The method was also successfully applied to obtain quantitative measures of changes in activity as a function of auditory stimuli in different neuronal populations of a same nucleus that project to different targets. D‐MEMRI, combined with other MRI techniques, clearly harbors potential for unraveling seasonal, hormonal, pharmacological or even genetically driven changes in a neuronal circuit, by simultaneously measuring changes in morphology, activity and connectivity. Copyright © 2004 John Wiley & Sons, Ltd.
Interference with one‐trial appetitive and aversive learning by ether and ECS
Authors: Herz Michael J.
Published: January 2005

Studies were undertaken to explore the effects of two amnesic agents upon appetitive and aversive learning in the same apparatus. Ss given electroconvulsive shock (ECS) within 80 sec or 15 min of punishing shock, and Ss administered ECS or ether 20 sec after the end of a 60‐sec water reinforcement period evidenced significant deficits on retention tests. The footshock‐ECS Ss showed significantly shorter latencies and greater activity than Ss given footshock alone. Conversely, Ss given water reinforcement and ECS had longer latencies and less activity than Ss given only water reinforcement. The results support the contention that postrial ECS and either disrupt perseverative neural processes representing appetitive as well as aversive learning and suggest the possibility that memory consolidation takes place at different rates for the two types of tasks.
L‐glutamate blockade of transmission at the giant synapse of the squid stellate ganglion
Authors: Kelly J. S. , Gage P. W.
Published: January 2005

The addition of L‐glutamate to the perfusion fluid of the squid stellate ganglion in concentrations from 5–100 mM led to a marked depression of the maximum rate of the rise of the PSP but never caused a detectable change in the membrane potential or conductance. In solutions containing 5 mM of glutamate, the reduction in the maximum rate of rise of the PSP occurred slowly and was incomplete after 60 min, however, in high concentrations the decline was much more rapid and the PSP disappeared completely. In glutamate free sea water the PSP rapidly reappeared and recovered its initial rate of rise in about 30 min. Since glutamate depression can be attributed to desensitization this result is consistent with the view that the transmitter substance is either glutamate or a chemically related compound. In the presence of 100–50 mM of magnesium the synapse is insensitive to 5 mM of glutamate and 10 mM is much less effective, perhaps as a result of magnesium glutamate binding. Thiosemicarbazide, an inhibitor of the enzyme system, glutamate decarboxylase, failed to cause an increase in the amplitude or duration of the PSP or an increase in potency of exogenous glutamate.
Effectiveness of temporal pattern in the input to a ganglion: Inhibition in the cardiac ganglion of spiny lobsters
Authors: Rao K. Pampapathi , Babu K. Sasira , Ishiko N. , Bullock Theodore H.
Published: January 2005

(1) The single inhibitor axon of one side, going to the cardiac ganglion of Panulirus in a preparation with the central nervous system removed, was stimulated at a constant mean frequency but with different temporal fine structure. In particular, inhibitory trains with uniform intervals are compared with trains of alternately short and long intervals (“paired pulses”). Different ratios of short to long interval were used and, besides pairs, groups of up to 8 shocks. (2) Sixteen different measures of the inhibitory effect upon various aspects of the electroneurogram of the heart beat are compared. Some are more sensitive, others are more consistent. (3) Pattern sensitivity is found, that is the heart beat slows to different extents for different temporal structures. Trains of uniform intervals were generally more effective than any other pattern. Bursts of 7 or 8 are less effective than shorter bursts with the same minimum and mean interval. (4) The same burst has a different effect according to the phase of the heart cycle at which it arrives; the later the arrival the greater the effect. At the optimal phase and impulse interval, the minimum number of impulses for a just noticeable inhibitory effect (5–10%) is about 4. (5) In some preparations aging was associated with a reversal from inhibition to acceleration and such changes were not necessarily in parallel for different stimulus patterns. (6) On present evidence it cannot be said that the pattern sensitivity is explained by the effect of conditioning shock‐test shock interval on the synaptic response to the test shock. (7) Evidence does not yet permit evaluation of the possible role of pattern sensitivity under normal conditions. The significance at presetn is the finding that in a nearly ideal preparation for testing, a postsynaptic neuron can “read,” i.e., respond differently to the same mean frequency according to temporal fine structure.
Electrophysiological studies of the protozoan, Stentor coeruleus
Authors: Wood David C.
Published: January 2005

Transmembrane potentials and membrane characteristics of Stentor coeruleus were studied by means of microelectrodes and standard electrophysiological techniques. Intracellular resting potentials were found to be variable and recordable for only a brief span of time owing to the encapsulation of the recording electrodes. During this brief time span of recorded resting potentials were anamolous in that they were generally of positive polarity.

When an extended Stentor was stimulated to contract, a 10–60 mv negative‐going transient response was recorded from intracellular electrodes. After the electrodes had been encapsulated, a diphasic transient response was observed when the penetrated animal contracted. Simultaneous recordings from intracellular and encapsulated electrodes showed that the diphasic and negative‐going transient responses occurred simultaneously.

Contractions of Stentor occurred in 7 to 8 msec following a 2 to 3 msec latent period after a suprathreshold shock. Records obtained by use of photomultiplier and microelectrodes indicated that the contractions began 1.8 msec after the onset of the diphasic response.

Prepotentials were observed prior to mechanically stimulated responses.
Amino acid uptake in the peripheral nerve of the rat
Authors: Yamaguchi Masashi , Yanos Theodore , Yamaguchi Tomoko , Lajtha Abel
Published: January 2005

When rat sciatic nerves were incubated with C14l‐lysine, l‐ or d‐glutamate, or d‐l γ‐aminoisobutyrate, the labeled compounds penetrated the nerve, and the level of lysine and leucine after 1 hr was higher in the nerve than in the medium. The level increased with time, and at 24 hr glutamate levels also were higher in the nerve than in the medium. Lowering the temperature strongly inhibited uptake, while other conditions such as absence of glucose, absence of sodium, or the presence of cyanide inhibited uptake by nerve less than uptake by brain slices. The uptake against a concentration gradient, and inhibitions of this uptake by metabolic inhibitors and by structural analogs, were interpreted as showing the presence of transport processes for amino acids in peripheral nerves with characteristics similar to such transport processes in the central nervous system.
Components of fast and slow axonal transport in the goldfish optic nerve
Authors: McEwen Bruce S. , Forman David S. , Grafstein Bernice
Published: January 2005

The composition of the fast and slow components of axonal transport in the goldfish optic nerve was investigated, using specific radioactive precursors injected into the eye. Tritiated glucosamine and fucose label macromolecules, presumably glycoproteins, which are rapidly transported from the eye to the optic tectum. Material labeled with these precursors is not evident in the slowly transported component. Glucosamine and fucose incorporation are blocked when a protein synthesis inhibitor, acetoxycycloheximide, is injected into the eye concurrently with the precursors. As well as labeling macromolecules, 3H‐glucosamine and 3H‐N‐acetylmannosamine ( a precursor of sialic acids) also label rapidly‐transported chloroform‐methanol‐extractable material which may contain transported glycolipids.

Two procedures were used to show that the slow component of axonal transport contains tubulin, a protein characteristic of the microtubules:

Tracer doses of tritiated colchicine injected into the eye label a wave of radioactivity which moves 0.5 mm/day, the rate of slow axonal transport in the goldfish optic nerve. We believe this wave represents the movement of colchicine which is bound to colchicine‐binding protein moving in the slow component of axonal transport.

Tritiated proline labels a slowly transported protein which is precipitated by vinblastine and has a mobility on polyacrylamide gels comparable to authentic tubulin. These results indicate that the fast and slow components of axonal transport each provide specific chemical substances to the nerve endings.