bluuebunny/crossref_metadata_2025 huggingface dataset:
Topographical localization of motor endplates in cryosections of whole human muscles
Authors: Aquilonius Sten‐Magnus , Askmark Håkan , Gillberg Per‐Göuran , Nandedkar Sanjeev , Olsson Yngve , Stårlberg Erik
Published: January 2005

The distribution of motor endplates in biceps brachii, tibialis anterior, and sartorius muscles from human adults was studied by staining longitudinal cryosections of whole muscle for cholinesterase. A special freezing technique was used to prevent the muscle from cracking before sectioning on a heavy cryostat microtome. The results from a large number of cryosections from biceps brachii and tibialis anterior muscles were analyzed by a computer and the topographical distributions of endplates in different views of the muscles were reconstructed. In the biceps brachii muscle, the endplates formed a fairly distinct, slightly V‐shaped band through the middle of the two heads. In the tibialis anterior muscle, the majority of the endplates were superficially distributed along the whole muscle. In the longitudinal sections from the middle part of the muscle, they gave the pattern of a parabola with its apex at the proximal end of the muscle. In the sartorius muscle, the endplates were scattered throughout the muscle and no endplate band was observed. The findings are in accordance with results obtained 30 years ago in investigations of muscle from small children and stillborn infants.
Myosin components of the latissimus dorsi and the pectoralis major muscles in the dystrophic chicken
Authors: Bandman Everett
Published: January 2005

The myosin composition of the anterior latissimus dorsi, the posterior latissimus dorsi, and the pectoralis major muscles was examined in the inbred White Leghorn dystrophic chicken and its isogenic normal line at different ages during development and maturation. Using the biochemical methods of native gel electrophoresis, one‐ and two‐dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE), and peptide mapping, it was found that myosin isozyme changes occurred normally in the anterior latissimus dorsi muscle. However, in the posterior latissimus dorsi muscle, slow myosin components which were not present in the adult normal muscle were present in the adult dystrophic muscle. In addition, the pectoralis major muscle of the dystrophic chicken failed to undergo the neonatal to adult fast myosin isozyme transition. Our data also showed that muscle cell cultures derived from the pectoralis major muscle of dystrophic chickens expressed identical myosin components to cultures derived from normal embryos. However, since these cultures only produced embryonic myosins even after 1 month in culture, it implied that cells in tissue culture were phenotypically normal because present cell culture conditions were insufficient to induce the fetal to adult isozyme changes.
Characterization of rabbit masseter muscle fibers
Authors: Mabuchi K. , Pinter K. , Mabuchi Y. , Sreter F. , Gergely J.
Published: January 2005

Myosins of histochemically distinguishable single fibers of rabbit masseter muscle—type 1, 2A, 2B, and slow fibers—have been characterized by gel electrophoresis under dissociating (sodium dodecyl sulfate) and nondissociating (inorganic pyrophosphate) conditions, and by analysis of peptide maps of the heavy chains following limited proteolytic degradation. Type 2B fibers contain more LC3 homodimer than type 2A fibers; peptide maps of their heavy chain are different although the two myosins comigrate on pyrophosphate gel electrophoresis. Slow fiber myosin migrates more slowly than fast myosin and has a distinct peptide map. Differences were also found among fibers of the same histochemical type but originating in different muscles. In adductor magnus 2B myosin the LC1 + LC3 heterodimer band is the strongest, while in masseter 2B myosin the heterodimer band is the strongest, while in masseter 2B myosin the heterodimer is the weakest. Statistical considerations suggest that in masseter there is a mechanism preferentially forming the homodimers. More work is needed to determine the mechanism by which phenotypical differences occur among various fiber types in the same muscle and between corresponding fiber types in different muscles.
Brominated vegetable oil myopathy: Inhibition at multiple sites
Authors: Carroll James E. , Norris Beverly J. , Villadiego Aida , Wheeler Steve D.
Published: January 2005

Skeletal muscle lipid storage was induced by feeding rats brominated vegetable oil (BVO). The defect was examined by measuring radioactive substrate oxidation, intermediates of fatty acid oxidation, and activities of oxidative enzymes. One‐ and U‐[14C] palmitate and 1‐[14C] pyruvate oxidation were reduced in muscle after four doses of BVO. Inhibition of U‐[14C] palmitate oxidation occurred after two doses. Short chain acylcoenzyme A(CoA) derivatives accumulated in the muscle. Several enzymes of β‐oxidation were significantly reduced, with the greatest reduction in 3‐ketoacyl‐CoA thiolase. The inhibition probably affected multiple sites of CoA and CoA‐derivative metabolism.
Evolution of nerve conduction velocity in later childhood and adolescence
Authors: Lang Heikki A. , Puusa Asko , Hynninen Pirkko , Kuusela Vesa , Jäntti Ville , Sillanpää Matti
Published: January 2005

Sensory and/or motor nerve conduction velocities (NCVs) were measured in median, radial, sural, and peroneal nerves of 54 healthy girls and 75 healthy boys aged 3–19 years. Independent of the nerve and sex, both motor and sensory NCVs increased in the upper extremities and decreased in the lower ones as a function of age/growth in length. NCV increased in the upper limbs on an average 3.17 m/sec in the boys and in the girls 1.47 m/sec per 10 years of life. As for the nerves of the lower extremities, NCV slowed down on the average 1.81 m/sec in the boys and in the girls 3.62 m/sec per 10 years of age. The change varied in different nerves. A highly significant one (P <0.001) was found in both the motor and sensory NCVs of peroneal nerve in the girls and in the sensory NCV of radial nerve in boys. On the average NCV was in most nerves faster in the girls than in boys of the same age. According to these results, changes occur in the function—and thus probably also in the morphology—of peripheral nerves even in later childhood and adolescence. These changes pertain to general maturation, growth in length of the limbs, and possibly also sex.
Alcoholic polyneuropathy
Authors: Shields Robert W.
Published: January 2005

Alcoholic polyneuropathy is a common disorder, characterized by nonspecific clinical, electromyographic, and pathologic features. Nerve conduction studies and needle electromyography disclose findings consistent with a generalized, sensorimotor, axonal degenerative, polyneuropathy. Alcoholic polyneuropathy may be suspected when such findings occur in the setting of long‐standing alcoholism and malnutrition. The lack of specific diagnostic criteria for alcoholic polyneuropathy requires that other potential etiologies be excluded before that diagnosis is made. The institution of a nutritionally‐balanced diet constitutes the principal therapy for alcoholic polyneuropathy, however, significant improvement following such therapy is not frequently seen.
Rat diaphragm: Changes in muscle fiber type frequency with age
Authors: Maltin Charlotte A. , Duncan Linda , Wilson Andrew B.
Published: January 2005

This study demonstrates age‐related changes in fiber type, distribution, and diameter that suggest that the diaphragm does not attain a static pattern of fiber type in adults. Furthermore, the progressive increase in the FG fiber diameters may be of importance in the interpretation of physiologic and biochemical parameters measured in the diaphragm muscle of animals of different age groups.
Causes of the increased fiber density in muscular dystrophies studied with single fiber EMG during electrical stimulation
Authors: Hilton‐Brown P. , Stålberg E. , Trontelj J. , Mihelin M.
Published: January 2005

The impulse transmission in motor end‐plates and along muscle fibers was studied with single fiber EMG in 13 patients with muscular dystrophy during intramuscular nerve stimulation and direct muscle fiber stimulation. For comparison, three patients with spinal muscular atrophy (SMA) and five normal subjects were studied. At nerve stimulation, 25% of the recordings in the patients with muscular dystrophy showed “increased” jitter (>55 m̈sec), 48% “normal” (10–55 m̈sec), and 27% “abnormally low” jitter (<5 m̈sec). At direct muscle fiber stimulation, the jitter was “abnormally low” in 91% of the recordings; 9% of the recordings had normal jitter. In SMA, no abnormally low jitter values were found. Increased jitter is a sign of impaired impulse transmission in immature intramuscular nerves and motor end‐plates. “Abnormally low jitter” suggests the presence of branched muscle fibers and ephaptic transmission between hyperexcitable fibers.
Stiffness and contractile properties of avian normal and dystrophic muscle bundles as measured by sinusoidal length perturbations
Authors: Feit Howard , Kawai Masataka , Schulman Michael I.
Published: January 2005

Both tension and stiffness as a function of muscle length were measured under relaxing conditions on isolated small bundles of chemically skinned myofibers from normal and dystrophic chicken pectoral muscles. It was shown that the dystrophic muscle was stiffer than normal muscle and developed more tension for the same amount of stretch. A fraction of stiffness was not removed by extraction with either 0.6 M Kl or with 5 M guanidine HCl mixed with 1% mercaptoethanol. The stiffness of dystrophic muscle was also unaffected by treatment with bacterial collagenase under conditions that destroyed the stiffness of tendon. Nyquist plots of normal and dystrophic muscles during calcium‐activated isometric contraction were very similar and were characteristic of fast‐twitch muscle, as evidenced by three clear exponential processes. The normal appearance of the Nyquist plot of dystrophic muscle demonstrates that cross‐bridge function is not altered, and the characteristic slowing of contraction and relaxation is not a consequence of a fast‐to‐slow transformation of muscle types. The increased stiffness of dystrophic muscle may be a very fundamental change in the biomechanics of dystrophy. We postulate that the stiffness is mediated by an altered form of collagen, which is collagenase‐resistant by virtue of excessive crosslinking.
Invited review: Neural control of phenotypic expression in mammalian muscle fibers
Authors: Pette Dirk , Vrbová Gerta
Published: January 2005

In this review, the present knowledge about the mechanisms involved in the control of the phenotypic expression of mammalian muscle fibers is summarized. There is a discussion as to how the activity imposed on the muscle fibers by the motoneuron finally induces in the muscle cells the expression of those genes that define its particular phenotype. The functional and molecular heterogeneity of skeletal muscle is thus defined by the existence of motor units with varied function, while the homogeneity of muscle fibers belonging to the same motor unit is yet another indication of the importance of activity in the control of gene expression of the mammalian muscle fiber.
F‐waves in neurogenic atrophy
Authors: Petajan Jack H.
Published: January 2005

F‐waves were determined in the peroneal nerves of 17 normal subjects, 11 amyotrophic lateral sclerosis (ALS) patients, and 13 patients with other disorders causing neurogenic atrophy (NA) in extensor digitorum brevis muscle. F‐waves were examined with regard to latency and waveform. Latency was increased above normal for both ALS and NA patients (P < 0.024 and P < 0.003, respectively). In normal subjects, the mean number of repeated responses (same latency and waveform) was 1.9 (r = 1.0–5.0), where 1.0 corresponds to no repeated response. In ALS patients, repeated responses were 2.9 (r = 1.2–7.8), which is not significantly different from normal (P < 0.099). In NA patients, repeated responses were 6.5 (r = 1.6–23), which is significantly above normal (P < 0.041). A dominant waveform occurred in 21.5% (mean) of responses in normal subjects (r = 4%–58%). In ALS and NA, corresponding values were 40.3% (r = 10%–88%) and 44.1% (r = 17%–100%), both of which were significantly above normal (P < 0.014 and P < 0.012, respectively). The distribution of F‐wave latencies is often nonrandom in normal, ALS, and NA subjects. The dominant F‐wave that was present in normal subjects and significantly increased in ALS and NA subjects may result from decreased numbers of motoneurons capable of contributing to the F‐response and would seem to be a useful additional measure of abnormality.
Screening for duchenne muscular dystrophy: An improved screening test for creatine kinase and its application in an infant screening program
Authors: Scheuerbrandt Günter , Lundin Arne , Lövgren Timo , Mortier Wilhelm
Published: January 2005

A kinetic bioluminescence assay with optimized reagent conditions has been developed for application as a screening test for increased creatine kinase (CK) activities in dried blood spots. This test is used for the early detection of Duchenne muscular dystrophy (DMD) in a voluntary CK screening program in West Germany of the 176,600 boys tested up to December 31, 1984, 48 who were less than 6 months old had certain or probable DMD (frequency 1: 3679). In 1983 and 1984, the rate of false positive results was 0.016% for a cut‐off activity 300 U/liter and 0.061% for a cut‐off activity 180 U/liter. Long‐term counseling is offered to families of newly detected DMD patients in order to facilitate the aims of the screening program, namely, avoidance of secondary cases in affected families, early professional care for the sick child, and the early opportunity to make the appropriate decisions for a life with an handicapped child. Two types of a benign hereditary blood anomaly were also detected by CK screening (CK‐BB inside erythrocytes or thrombocytes).
Electromyographic findings in different forms of infantile and juvenile proximal spinal muscular atrophy
Authors: Hausmanowa‐Petrusewicz Irena , Karwańska Anna
Published: January 2005

Quantitative electromyography (EMG) was performed in 223 infantile and juvenile cases of spinal muscular atrophy (SMA), which were classified into 3 groups: (A) form la, Werdnig‐Hoffmann disease; (B) forms lb and II, intermediate forms; and (C) form III, Kugelberg‐Welander disease. The groups differed in the occurrence of spontaneous activity; only groups A and B showed spontaneous rhythmic firing of motor units, whereas in long‐standing cases, pseudomyotonic volleys appeared. The parameters of individual motor unit potentials (MUPs) differed in the different forms of the disease. Group A showed, in addition to long potentials of high amplitude, some short and low amplitude potentials, and the histograms of amplitudes and durations were bimodal. In the long‐standing cases, the values of these parameters were shifted to longer durations and higher amplitudes of motor unit potentials. However, in long‐standing cases of the benign group C, the short, low potentials appeared as well as socalled linked potentials. In the very early stage of the disease, the children who were found to be suffering from chronic forms of SMA—both malignant (form lb and II or benign group C)—had an EMG record that was slightly different from that of acute form la. Their EMG record shows more so‐called “spinal” signs, particularly in the benign group C (Kugelberg‐Welander disease). These increasing features of chronic anterior horn cell involvement followed a pattern of reinnervation and hypertrophy of muscle fibers. These phenomena were particularly seen in the benign group C. These findings indicate that in the early stage of SMA, the EMG not only has diagnostic, but also prognostic, value.
Congenital myasthenia: Further evidence of disease heterogeneity
Authors: Lecky B. R. F. , Morgan‐Hughes J. A. , Murray N. M. F. , Landon D. N. , Wray D. , Prior C.
Published: January 2005

The findings in two cases of congenital myasthenia investigated by intercostal muscle biopsy are presented. The first case, a 16‐year‐old boy, showed reduced miniature endplate potential amplitude and normal 125l‐α‐bungarotoxin binding to postsynaptic acetylcholine receptors. Muscle biopsy and endplate ultrastructure were normal. Tubocurarine affinity, ion channel properties, and passive membrane properties were normal. Limited data showed reduced effectiveness of applied acetylcholine in opening ion channels. The second case was an 18‐year‐old girl with consanguineous parents. Type 2 muscle fiber atrophy was seen in both limb and intercostal muscle. Intercostal endplates were elongated, although ultrastructure was normal. Negligible postsynaptic α‐bungarotoxin binding suggested an abnormality of the acetylcholine receptor macromolecule.
Muscle stiffness and electrical activity in paramyotonia congenita
Authors: Ricker Kenneth , Rüdel Reinhardt , Lehmann‐Horn Frank , Küther Gerald
Published: January 2005

To investigate the pathomechanism of paramyotonic stiffness, the mechanogram of isometric finger force and the electromyogram of the flexor digitorum muscle were simultaneously recorded in five unrelated paramyotonia congenita patients. Cooling of the forearm provoked “spontaneous” electrical activity, but the accompanying force was <5% of the maximal voluntary isometric contraction amplitude. The relaxation of maximal voluntary contractions executed in the cold had a normal first phase and a very slow second phase. The force amplitude at the beginning of the slow phase was up to 80% of the maximal contraction amplitude; the duration of the slow phase was up to several minutes. It was concluded that the slowed muscle relaxation is more important as a factor contributing to paramyotonic stiffness than spontaneous force generation. Involuntary electrical activity recorded during the slow relaxation phase was too low to account for the force. Intercostal muscle biopsies obtained from four patients showed similar phases of slow relaxation when stimulated to give isometric twitches or tetani in the cold. Extracellular recording with electrodes designed to pick up all activity from the small bundles clearly showed that the slow relaxation phase was not caused by spontaneous action potentials. One possible explanation for the slowed relaxation is a long‐lasting depolarization‐induced contracture of the muscle fibers following activation in the cold.
Correlation of 1A afferent conduction with the ataxia of fisher syndrome
Authors: Weiss Jacquelyn A. , White James C.
Published: January 2005

The pathophysiology of the ataxia in Fisher syndrome (the syndrome of acute ophthalmoplegia, ataxia, and areflexia) has been attributed to both peripheral nervous system pathology and cerebellar system dysfunction. Pathologic studies have demonstrated no consistent central nervous system abnormalities. We present a case in which abnormalities of 1a sensory conduction were found to correlate directly with the degree of ataxia, without impairment of motor or cutaneous sensory conduction. We propose that the ataxia seen in typical Fisher syndrome may be due to demyelination of 1a afferent fibers.
Simulation and analysis of the electromyographic interference pattern in normal muscle. Part II: Activity, upper centile amplitude, and number of small segments
Authors: Nandedkar Sanjeev D. , Sanders Donald B. , Stålberg Erik V.
Published: January 2005

We have defined three new features of the electromyographic (EMG) interference pattern (IP): activity, upper centile amplitude (UCA), and number of small segments (NSS). These parameters were measured in simulated IPs constructed by adding together motor unit action potentials (MUAPs) recorded with a concentric needle EMG electrode. The activity increases linearly with the number of MUAP discharges to approximately 80% of its theoretical maximum value. The UCA correlates strongly with the peak‐to‐peak amplitude of the largest MUAP in the IP and the mean segment amplitude and does not depend on the discharge rate of the largest MUAPs. We infer that the UCA defines the upper limit of the peak‐to‐peak amplitude of the MUAPs contained in the IP. The NSS increases with the number of MUAP discharges, but reaches a constant value at higher MUAP discharge rates, probably because small amplitude MUAPs are masked by the large amplitude MUAPs. The potential value of these parameters in automated IP analysis is discussed.
Quantitative freeze—fracture studies of membrane changes in chicken muscular dystrophy
Authors: McLean Barbara , Mazen‐Lynch Laila , Shotton David M. , McLean Gregor A.
Published: January 2005

Muscular dystrophy induces extensive changes in the patterning of sarcolemmal caveolae of fast‐twitch fibers from the chicken posterior latissimus dorsi (PLD) muscle, which in healthy fibers are arranged in striking bands over the myofibrillar I‐bands. In dystrophic fibers the caveolae lack this patterned arrangement, and instead are dispersed over the entire sarcolemma, are irregular in shape, and are more numerous in older birds. Quantitative analysis of these differences provides three independent numerical indices of the dystrophic state and suggests that constraints responsible for normal patterning are lost in diseased fibers. These observations support theories that defects of the muscle plasma membrane are important for dystrophic pathogenesis in contrast, the sarcolemma of slow tonic fibers from anterior latissimus dorsi (ALD) and metapatagialis latissimus dorsi (MLD) muscles have randomly dispersed caveolae whose appearance and distribution are unaffected by the disease.
Passively transferred lambert‐eaton syndrome in mice receiving purified IgG
Authors: Kim Yong I.
Published: January 2005

Purified IgG antibodies were prepared by ion‐exchange chromatography from the plasma of a patient with nonneoplastic form of the Lambert‐Eaton myasthenic syndrome (LES). The antibodies were injected into mice with daily doses of 0.15–10 mg for 20–22 days, following which the integrity of neuromuscular transmission was assessed in vitro in phrenic nerve‐diaphragm muscle preparations. The injected animals manifested electrophysiologic features of human LES, which were characterized by: (1) dose‐dependent reduction in the quantal content of nerve‐evoked endplate potentials, (2) an abnormally small increase in the frequency of spontaneous miniature endplate potentials (MEPPs) with elevated [K+]0, and (3) normal MEPP amplitude with no evidence of postjunctional deficiency. Crude immunoglobulins (Igs) from the same patient and two LES patients with associated malignancy similarly transferred the defects in quantal transmitter release. In contrast, animals receiving Igs from control subjects or from a patient with small‐cell carcinoma of the lung manifested no functional impairment of neuromuscular transmission. Instead, the evoked release in these animals was significantly enhanced relative to that found in normal untreated mice. These results suggest that an IgG antibody produces the presynaptic impairment that is characteristic of LES and support the concept that LES with and without cancer has an autoimmune pathogenesis.
Diabetic thoracic radiculopathy: Electrodiagnostic study
Authors: Streib Erich W. , Sun Sallie F. , Paustian Frederick F. , Gallagher Thomas F. , Shipp Joseph C. , Ecklund Robert E.
Published: January 2005

We investigated the diagnostic value of electromyographic (EMG) examination of the anterior abdominal wall muscles (AWMS) in thoracic radiculopathy and compared it with examination of thoracic paraspinal muscles (TPSM). Technically, examination of AWMS was much easier compared to TPSM. In eight patients with thoracic diabetic radiculopathy at the level of T7‐T12, AWMS was abnormal in all and was considered to be diagnostic whereas AWMS was normal in diabetic lumbar radiculopathy, patients with diabetes mellitus without radiculopathy, patients with unspecified gastrointestinal pain, and patients with musculoskeletal‐type back pain. We conclude that EMG evaluation for possible thoracic radiculopathy should include examination of AWMS, and if abnormal, would be of great diagnostic help in patients with unspecified gastrointestinal symptoms.
Surgery for thoracic outlet syndrome may be hazardous to your health
Authors: Cherington Michael , Happer Ian , Machanic Bennett , Parry Lynn
Published: January 2005

We are reporting five patients who suffered serious injuries from surgery for thoracic outlet syndrome, which has been a controversial subject from many aspects. Many argue that it is much overdiagnosed and overtreated. The term „disputed thoracic outlet syndrome”︁ has recently been applied to the majority of cases in which there are little or no clinical findings. The much more rare true neurogenic thoracic outlet syndrome does have associated neurologic and electrical findings. Recently, the use and misuse of electrodiagnostic studies in the diagnosis of disputed thoracic outlet syndrome has been discussed in the literature. The cases that we are reporting are especially tragic because the elective surgeries were performed in patients who had little or no clinical abnormalities on examination prior to the surgery.
Ionic channels: II. Voltage‐ and agonist‐gated and agonist‐modified channel properties and structure
Authors: Ruff Robert L.
Published: January 2005

This article reviews the different forms of ionic channels: voltage‐gated, agonist‐gated, and agonist‐ and second messenger‐modified channels. The recent advances in our knowledge of the amino acid sequence of the sodium channel and the nicotinic acetylcholine receptor and the relationship of the primary structure to the channels' quarternary structure and function are discussed.
Thalidomide neuropathy: An electrophysiologic study
Authors: Lagueny Alain , Rommel Antoine , Vignolly Bernard , Taieb Alain , Vendeaud ‐busquet Marie , Doutre Marie S. , Julien Jean
Published: January 2005

Thalidomide is effective in the treatment of such disabling dermatologic diseases as aphthosis, discoid lupus erythematosus, and prurigo nodularis, in which other drugs fail. However, its use can induce neuropathy necessitating caution in its administration. It was found in this electrophysiologic study of 13 patients that the data best revealing neuropathy, even when clinical abnormalities were not apparent, were reduction of sensory nerve action potential amplitude on the sural nerve, increase of somatosensory evoked potential latency following sural nerve stimulation, and reduction of sensory action potential amplitude on stimulating the median nerve at the wrist. In two patients, electrophysiologic abnormalities had increased after withdrawal, suggesting a prolonged action of thalidomide. Timely reduction of dosage, after detection of changes indicating the onset of side effects, could reduce the risk of the sometimes rapid emergence of clinical symptoms.
Studies on the pathogenesis of vincristine‐induced neuropathy
Authors: Sahenk Zarife , Brady Scott T. , Mendell Jerry R.
Published: January 2005

The pathogenesis of the peripheral neuropathy induced by vincristine is poorly understood, but interference of vinca alkaloids with microtubule assembly suggests that microtubule changes could be important. This possibility was studied by directly exposing the rat sciatic nerve to graded concentrations of vincristine sulfate. Microtubule length histograms prepared from randomly selected axons showed a unimodal distribution in vincristine and control axons. In vincristine‐exposed axons, however, there was a shift to shorter length microtubules, and the mean measured length of microtubules (0.42 ± 0.37 μm) was significantly (P < 0.001) shorter than controls (0.67 ± 0.55 μm). On cross‐sections, the vincristine‐exposed axons showed a decrease in the number of microtubules per square micrometer of axonal area compared to controls. These findings fit best with a loss of portion(s) of each microtubule and support the possibility that microtubules consist of both stable and labile segments. The microtubule changes were associated with malorientation of microtubules and neurofilaments, accompanied by free vesicle accumulation and fragmentation of the smooth endoplasmic reticulum. These structural alterations would account for the previously observed abnormalities in axoplasmic transport and would also provide insight into the commonly observed peripheral neuropathy induced by vincristine treatment.
Slow‐type C‐protein in dystrophic chicken fast pectoralis muscle
Authors: Obinata Takashi , Shinbo Kazuhiko
Published: January 2005

C‐protein isoform expression in hereditary dystrophic chicken skeletal muscle was compared with that in normal chicken muscle during postnatal development by immunocytochemical and immunoblot methods. In the pectoralis muscle (PM) of both normal and dystrophic chicken, slow‐ and fast‐type C‐proteins were coexpressed in the vast majority of myofibers at neonatal age, but the slow C‐protein disappeared, leaving continued expression of only the fast‐type C‐protein as muscle development progressed up to 2 weeks posthatch. In the dystrophic chicken PM, however, myofibers containing slow‐type C‐protein reappeared about 1 month posthatch and increased in number with the progression of muscular dystrophy. We conclude that C‐protein isoform expression in dystrophic myofibers resembles that in neonatal myofibers and that the expression of slow‐type C‐protein can be seen as a marker for chicken muscular dystrophy.
Recent views on amyotrophic lateral sclerosis with emphasis on electrophysiological studies
Authors: Bradley Walter G.
Published: January 2005

Peripheral electrophysiological studies are of particular value for elucidating the anatomy and pathophysiology of neuromuscular diseases, but they can also help in providing clues to the etiology of the disease. Recent studies of the motor units in chronic denervating conditions including amyotrophic lateral sclerosis (ALS) are reviewed. These indicate that reinnervation is a relatively active process which compensates for the progressive loss of motoneurons in ALS until more than 50% of the motoneurons have died. There seems to be no predilection for death of motoneurons of any particular size in ALS. Fasciculations may arise both proximally and distally. The dying‐back change is not a major feature of ALS. These and other data cast doubt on the etiological theories that ALS arises from premature aging of motoneurons, deficiency of motoneuron trophic factors, or an inhibitor of a motoneuronal sprouting factor, and point to the need to study metabolic changes intrinsic to the motoneuron in ALS.
Hormonal control of muscle growth
Authors: Florini James R.
Published: January 2005

In muscle of whole animals, pituitary growth hormone, the thyroid hormones, and insulin are major growth‐promoting hormones, and the glucocorticoids have significant catabolic actions. At the cellular level the primary anabolic hormones for cultured myoblasts are the somatomedins (insulin‐like growth factors) and fibroblast growth factor. In these cells physiological concentrations of growth hormone, thyroid hormones, and insulin have no growth‐promoting effect; some of the reported actions of insulin probably result from cross‐reaction with the somatomedin receptor. Results with purified proteins do not support the view that mitogens block myoblast differentiation; transforming growth factor‐beta and interferon are nonmitogenic proteins that inhibit differentiation, insulin‐like growth factors are mitogens that stimulate differentiation, and fibroblast growth factor is the only purified mitogen that inhibits differentiation. At least six serum‐free media have now been devised for the growth of various kinds of muscle cells under closely defined conditions.
Pedictors of patients' expreience of pain in EMG
Authors: Khoshbin Shahram , Hallett Mark , Lunbeck Robert
Published: January 2005

The important features that predict the amount of pain experienced by patients with low back pain who undergo needle electromyography were the patients' assessment of their own pain, their trait‐anxiety levels, and female sex. Although it does not influence EMG pain, information about the test will decrease the anxiety of patients coming for testing.
Sympathetic skin response in diabetic neuropathy
Authors: Soliven Betty , Maselli Ricardo , Jaspan Jonathan , Green Andrew , Graziano Hank , Petersen Michele , Spire Jean‐Paul
Published: January 2005

The sympathetic skin response (SSR) was studied in 47 diabetic patients selected for the presence of symptoms and clinical signs of peripheral neuropathy and in 24 normal control subjects. The SSR was present in all controls but was absent at the foot in 66% and at the hand in 27.7% of the diabetic patients. Absence of the SSR failed to correlate with other electrophysiologic parameters on routine nerve conduction and electromyographic studies. Although absent SSR was more often found in patients with symptoms of autonomic dysfunction (P < 0.05), there was no correlation with any specific symptoms of autonomic involvement. The SSR was frequently absent, at least in the foot, in those patients with abnormal cardiac beat‐to‐beat variability (expiratory: inspiratory, E:I, ratio) and pupil cycle time (PCT). In addition there was a good correlation between the amplitude of the SSR and the value of the E:I ratio (r = 0.81,P < 0.001). The SSR may be a valuable adjunct in the assessment of autonomic involvement in diabetic neuropathy, but its sensitivity requires further evaluation.
The effect of temporal dispersion on compound action potential area in human peripheral nerve
Authors: Olney Richard K. , Budingen Hans J. , Miller Robert G.
Published: January 2005

In 32 ulnar nerves of healthy volunteers, the mean area of the compound muscle action potential recorded over abductor digiti minimi was reduced by 7.4% when comparing above‐elbow with wrist stimulation and by 1.9% when comparing above‐elbow with below‐elbow stimulation. In 20 of these nerves, the mean area of the compound nerve action potential (CNAP) recorded over the fifth digit was reduced by 36% when comparing above‐elbow with wrist stimulation. Area reduction of the compound action potential, especially of the CNAP, appears to be a characteristic effect of temporal dispersion in peripheral nerve when utilizing the bipolar recording technique routinely employed in clinical neurophysiology. A thorough understanding of the effects caused by temporal dispersion and of their quantitative limits in normal peripheral nerve is important for the proper interpretation of nerve conduction studies.
Response to total body irradiation in dermatomyositis
Authors: Kelly John J. , Madoc‐Jones Hywel , Adelman Lester S. , Andres Patricia L. , Munsat Theodore L.
Published: January 2005

There were two patients with severe dermatomyositis refractory to immunosuppressive therapy treated with 150 rad of total body irradiation given over a period of 5 weeks. Both patients responded promptly with minimal side‐effects and remain in partial remission 42 and 18 months after completion of the treatment. Total body irradiation is effective in some patients with dermatomyositis who are refractory to standard therapy.
Expression of fiber type specific proteins during ontogeny of canine temporalis muscle
Authors: Shelton G. Diane , Cardinet George H. , Bandman Everett
Published: January 2005

The canine masticatory muscles contain a unique adult fiber type composition and different contractile protein isoforms than do adult limb muscles. To determine when these characteristic proteins are expressed during development, samples from canine temporalis (masticatory) and pectineus (limb) muscles were compared between 55 days gestation and 60 days postpartum by histochemical, biochemical, and immunocytochemical analysis. At 55 days gestation and 3 days postpartum, both muscles contained identical histochemical type 2C fibers, native myosin isozymes, and myosin light and heavy chains. By 14 days postpartum, fiber‐type expression in these muscles diverged, with resultant formation of type 1 and type 2M fibers in the temporalis muscle and type 1 and 2A fibers in the pectineus muscle. The distinctive myosin isoforms, light chains, and heavy chain of the temporalis muscle were also expressed 2 weeks postpartum. Based on the methods used in this study, we conclude that (1) the temporalis muscle develops from embryonic fibers that initially contain a myosin indistinguishable from embryonic limb muscle fibers, suggesting they have a common precursor, and (2) the myosin light chains and heavy chain unique to the temporalis muscle are initially expressed 2 weeks postpartum.
Adaptation of skeletal muscle to immobilization in a shortened position
Authors: Baker James H. , Matsumoto Dan E.
Published: January 2005

This study determined the morphological changes and adaptations that occur following immobilization of rat soleus and gastrocnemius muscles when the ankle joint is placed in complete plantar flexion for 2, 5, 7, 14, 21, and 28 days by means of plaster casts. Previous studies of such shortened muscles have shown that the number of sarcomeres in series is reduced, but how the sarcomeres are reduced has not been determined. We observed that the fibers in the midbelly region of the muscles demonstrated a progressive degenerative process over the first few weeks. Myofibrils across the entire width of the affected fibers underwent dissolution. However, by 4 weeks new myofibrils were being formed, and sarcomere lengths appeared normal. Portions of the fibers near the tendon underwent segmental necrosis. These findings are similar to the response of the soleus and gastrocnemius muscles to tenotomy and are clinically relevant to orthopedic procedures that maintain muscles in shortened conditions for prolonged periods.
Muscle imaging in neuromuscular disease using computerized real‐time sonography
Authors: Fischer Asma Q. , Carpenter Darrell W. , Hartlage Patricia L. , Carroll James E. , Stephens Sharon
Published: January 2005

The results of a study utilizing computerized real‐time sonography (CRS) to image muscles in patients with neuromuscular disease are presented for 67 patients, 37 with neuromuscular disease and 4 with upper motor neuron disease, and 26 age‐matched healthy controls between the ages of 2 days and 59 years. CRS is a safe, noninvasive, atraumatic method for evaluating a broad range of neuromuscular diseases. It is capable of differentiating myopathies or dystrophies from neurogenic atrophies and floppy infants with “central” hypotonia from those with neuromuscular diseases.
Spatial distribution of fiber types in skeletal muscle: Test for a random distribution
Authors: Venema Henk W.
Published: January 2005

A statistical test is introduced for the assessment of fiber type grouping based on the number of neighboring fibers of different histochemical type. It is conceptually simple and can be applied to regular and irregular fiber patterns alike. One important feature of this test is that it has more power than existing ones, which means that deviations from a normal situation can be detected in an earlier stage than with any other method. The dependency of the outcome of the test on type‐specific size differences is rather small. Moreover, a method is given to correct for this bias. With the aid of the test it is shown that in normal muscle tissue of young persons a slight segregation of fiber type is a common situation.
Comparison of acoustic and electrical signals from erectores spinae muscles
Authors: Stokes Ian A. F. , Moffroid Mary S. , Rush Stanley , Haugh Larry D.
Published: January 2005

Comparison was made between simultaneous recordings of the electromyogram (EMG) and acoustic myogram (AMG) signals and the torque produced by the lumbar erectores spinae muscles of three healthy subjects while they performed isometric contractions. Repeatability of each signal was studied. The AMG had a relationship to the torque which was more quadratic than linear, whereas that of the EMG was more linear. The coefficient of variability of residuals about a „best‐fit”︁ line was 8.55% for torque‐increasing EMG recordings and 19.2% for torque‐increasing AMG recordings. At the same torque, the EMG was on average about 10% greater for increasing‐torque recordings than for decreasing‐torque parts of the recordings, but the magnitude of the AMG signal was about 10% less. With repeated testing on the same day, the coefficient of variability of the signal/torque relationship (torque‐increasing) was 9% for EMG and 23% for AMG signals. With long‐term testing over 2 weeks these coefficients were 23 and 39%, respectively. Correlation analysis showed that the two signal/torque relationships varied independently of each other.
Neurovascular‐anastomosed muscle grafts in rabbits: Functional deficits result from tendon repair
Authors: Guelinckx Paul J. , Faulkner John A. , Essig David A.
Published: January 2005

In rabbits, 9 g rectus femoris (RFM) muscles were grafted with tendon repair and with (1) nerves and blood vessels intact, (2) nerves intact and blood vessels anastomosed, or (3) nerves and blood vessels anastomosed. The influences of tendon, nerve, and vascular repair on the functional capabilities of grafts were compared 15–120 days after grafting. Data were collected on the mass, total protein content, oxidative capacity, maximum force development, and fatigability of grafts and control RFM muscles. When stabilized 90–120 days after grafting, mean values for the three types of grafts were not significantly different. Compared with values for control RFM muscles, each type of graft had significantly lower mean values for mass, total protein content, and maximum force, but the grafts were more resistant to fatigue. In RFM grafts, nerve and vascular repair do not contribute significantly to the impairments. Consequently, tendon repair appears to be responsible for the major functional deficits.
Spinal roots of rats poisoned with methylmercury: Physiology and pathology
Authors: Arimura K. , Murai Y. , Rosales R. L. , Izumo S.
Published: January 2005

The evoked potentials in the ventral and dorsal roots were recorded independently by stimulating the sciatic nerve of both control and methylmercury‐poisoned rats. Poisoned rats showed markedly decreased amplitudes but normal latencies of the potentials evoked in the dorsal roots. Potentials evoked in the ventral roots had normal latencies and amplitudes. Pathological correlates indicated acute axonal degeneration of the dorsal roots, with a significant decrease of the large and small myelinated fiber densities. The ventral roots were histologically unremarkable. Our pathological confirmation of the electrophysiologic changes in the methylmercury‐poisoned rats enables us to substantially assess the pathophysiological aspects of acute lesions in the spinal roots.
Small‐caliber skeletal muscle fibers do not suffer necrosis in mdx mouse dystrophy
Authors: Karpati George , Carpenter Stirling , Prescott Steven
Published: January 2005

The prevalence of internal nuclei in muscle fibers (centronucleation), which is a reliable cumulative index of all prior muscle fiber necrosis, was measured at different ages in different muscles of mdx mice and was correlated with muscle fiber diameter. The prevalence of centronucleated fibers (as percentage of total number of fibers) rose gradually after age 20 days until it reached a peak level of 80% at age 60 days. No significant centronucleation (or necrosis) was observed in the following circumstances: in 4 different limb muscles before age 15 days, in leg muscles that were denervated by peripheral nerve section or rendered immobile by high thoracic cordotomy at 15 days, or in rotator extraocular muscles throughout the animals' life span. In these situations, muscle fiber diameter remained below approximately 20 μm. The mechanism by which small‐diameter fibers are resistant to necrosis in mdx dystrophy is unknown, but a similar situation exists in hamster and Duchenne muscular dystrophy.
Serum CK, calcium, magnesium, and oxidative phosphorylation in mdx mouse muscular dystrophy
Authors: Glesby Marshall J. , Rosenmann Eduardo , Nylen Edward G. , Wrogemann Klaus
Published: January 2005

Serum creatine kinase (CK) activity, calcium (Ca) and magnesium (Mg) contents of skeletal muscle and isolated mitochondria, as well as oxidative phosphorylation of X‐linked muscular dystrophic (mdx) mice were compared with normal control animals at ages 5, 10, and 23 weeks. Serum CK is elevated in mdx mice at all ages, with highest activities at 5 weeks. The Ca content of dystrophic skeletal muscle is increased at all ages, whereas no clearly abnormal trend in muscle Mg levels was observed. Noncollagen protein (NCP), which was used as a reference base, is significantly diminished in muscle from 10‐ and 23‐week‐old mdx animals. Isolated mitochondria from mdx mice have elevated calcium content and decreased respiratory control ratios with NAD‐linked substrates pyruvate/malate. The findings are distinct from those in dystrophic mice, strain 129/ReJ, but similar to observations in dystrophic hamsters and Duchenne muscular dystrophy and reflect the occurrence of overt muscle cell necrosis.
Single‐channel activity in sarcolemmal vesicles from human and other mammalian muscles
Authors: Burton F. , Dörstelmann Ursula , Hutter O. F.
Published: January 2005

Segments of mammalian, including human, skeletal muscle 1–2 cm long can be induced to shed vesicles by treatment with collagenase in a high‐KCl solution containing no added calcium. The vesciles are encompassed by clean sarcolemma so that the gigaseal necessary for patch‐clamping is readily formed. The properties of inwardly rectifying potassium channels and of calcium‐activated potassium channels in patches detached form such vesicles are shown to be consistent with expectations based on earlier studies on intact muscle fibers and with patch clamp results on the same type of channels in other tissues. A cholride channel which rectifies outwardly with a conductance ranging from 15 to 50 pS is also described. The utility of sarcolemmal vesicles for the study of ion channels in human biopsy material is discussed.
Changes in skeletal muscle gene transcription induced by chronic stimulation
Authors: Brownson Carol , Isenberg Harvey , Brown Wendy , Salmons Stanley , Edwards Yvonne
Published: January 2005

The mRNA products of four genes, carbonic anhydrase III (CAIII), fast myosin heavy chain (MHCf), actin and glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), were assayed by Northern and slot‐blot analysis in rabbit tibialis anterior and extensor digitorum longus muscles that were subjected to electrical stimulation for periods of up to 21 days. Marked changes in mRNA levels were seen for all four genes. The mRNA for CAIII, which is specific for type 1 fibers, rose significantly, whereas the MHCf mRNA fell markedly in the stimulated muscles. Changes in GAPDH mRNA were consistent with a reduced dependence on anaerobic glycolysis as an energy source. Actin mRNA levels were noticeably depressed in the early stages of stimulation. Thus for several classes of muscle protein, the response to chronic low‐frequency stimulation appears to involve changes at the level of gene transcription.