bluuebunny/crossref_metadata_2025_split huggingface dataset:
Progressive myotonia in foals resembling human dystrophia myotonica
Authors: Reed Stephen M. , Hegreberg Gerald A. , Bayly Warwick M. , Brown Christopher M. , Paradis Mary R. , Clemmons Roger M. 
Published: January 2005

AbstractA severe and progressive neuromuscular disorder accompanied by clinical, electrophysiological, and pathological features resembling human dystrophia myotonica was observed in three foals. This disorder was apparent as early as 1 month of age and involved progressive skeletal muscle dysfunction, initially characterized by proximal muscle hypertrophy and hypertonicity with subsequent muscle stiffness, weakness, and atrophy. Multisystem involvement was manifested in one case by testicular hypoplasia, early cataract formation, and borderline glucose intolerance. Prolonged dimpling of these large rear‐limb muscles was elicited by percussion. Myotonic discharges were identified by electromyography. Percussion dimpling and the typical myotonic discharges persisted after neuromuscular blockade. Distinctive histologic muscle changes included ring fibers, sarcoplasmic mass formation, variation in fiber diameter size, and internally positioned nuclei.
Polysaccharide storage myopathy
Authors: Thompson A. J. , Swash M. , Cox E. L. , Ingram D. A. , Gray A. , Schwartz M. S. 
Published: January 2005

AbstractIn a woman with a slowly progressive adult onset proximal myopathy, muscle biopsy showed storage of PAS positive material in type 1 fibers. This material consisted of a branched chain polysaccharide associated with a mucoprtein. No abnormality of glygogen‐pathway enzymes was detected. This suggested that this polysccharide accumulation occurred because the polysaccharide was laid down in a non 7hyphen;bioavailable form. The clinical and histochemical features in this patient and in the few similar reported cases indicate that polysaccharide storage myopathy is a distinct entity that is allied to the glycogen storage myopathies.
Effects of denervation on spectrin concentration in avian skeletal muscle
Authors: Gregorio Carol C. , Hudecki Michael S. , Pollina Catherine M. , Repasky Elizabeth A. 
Published: January 2005

AbstractThe effect of denervation on avian muscle α‐spectrin was examined in fast and slow muscles. Using immunofluorescence, the surgically denervated fast‐twitch posterior latissimus dorsi (PLD) exhibited a significant increase in spectrin antigen associated with the sarcolemma and within the sarcoplasm compared with the contralateral innervated control muscle. Using gel electrophoresis followed by immunoblotting, we found a two‐ to three‐fold increase in the levels of spectrin in the denervated PLD over that found in the innervated PLD. These levels were comparable to those found previously in slow and dystrophic muscle. The intrafiber distribution of spectrin is similar between the denervated PLD and the slow‐tonic anterior latissimus dorsi (ALD). When spectrin was examined in dystrophic PLD muscle, denervation was found to have no effect. These results support our hypothesis that the concentration of spectrin within muscle fibers reflects the physiological state of those fibers. Changes in spectrin concentration may be a useful probe to study the various alterations in physical parameters found among fast, slow, dystrophic, and denervated fibers.
Jamaican neuropathy: An electrophysiological study
Authors: Barkhaus Paul E. , Morgan Owen 
Published: January 2005

AbstractJamaican neuropathy (JN) is a common disorder in Jamaica and has characteristics similar to neurological diseases found in other tropical areas. JN is a clinical syndrome and occurs in two forms: spastic and ataxic. This is the first known electrophysiological study of this disease. In the spastic group of JN, peripheral electrophysiological findings were mostly normal, suggesting a central cause for their symptoms. The only patinet with the ataxic form of JN had a chronic axonal peripheral neuropathy.
The myotonic mouse mutant ADR: Physiological and histochemical properties of muscle
Authors: Reininghaus Jutta , Füuchtbauer Ernst‐Martin , Bertram Kordula , Jockusch Harald 
Published: January 2005

AbstractThe muscle physiology and histochemistry of a hereditary neuromuscular syndrome of the mouse, “arrested development of righting response” (ADR), was studied. The speed of single twitches of fast ADR limb muscles was normal up to an age of about 60 days but decreased at later ages. At any age between 10 and 120 days postnatal, fast and slow muscles of the mutant displayed after‐contractions of 1–3 (5) seconds duration. These coincided with electrical after‐activity of muscle, as demonstrated by electromyography, After‐contractions and EMG signals were suppressed by the membrane‐stabilizing drug tocainide. These physiological data suggest that ADR is a myotonia. With a few exceptions, limb and trunk muscles of ADR animals showed a uniform oxidative phenotype with a lack of large diameter glycolytic fibers. The histochemical muscle phenotype of the ADR mouse was partially reversed by a long‐term treatment with tocainide.
Neonatal androgen maintains sexually dimorphic muscles in the absence of innervation
Authors: Fishman Renata B. , Breedlove S. Marc 
Published: January 2005

AbstractWe examined the site of androgen action in maintaining the sexually dimorphic spinal nucleus of the bulbocavernosus (SNB) and its target perineal muscles, the bulbocavernosus (BC) and levator ani (LA), in rats. To determine whether androgen action on SNB motoneurons is crucial for BC/LA survival, we removed SNB cells in newborn female rats by lumbosacral spinalectomy, administered testosterone propionate (TP) on days 1 and 3 of life, and examined for the presence of BC/LA muscles in adulthood. BC/LA muscles were present in all TP‐treated spinalectomized females, and staining of these muscles with alpha‐bungarotoxin or for acetylcholinesterase showed no evidence of cholinergic innervation. Thus, complete neonatal denervation of the BC/LA does not prevent TP from sparing these muscles, suggesting that androgen acts directly upon BC/LA muscles to maintain them during development. This androgenic maintenance of the BC/LA may be crucial for the survival of SNB motoneurons.
Microneurography for the recording and selective stimulation of afferents: An assessment
Authors: Calancie Blair M. , Stein R. B. 
Published: January 2005

AbstractThe purpose of this study was to examine whether a microneurography electrode could record from and then selectively stimulate the same afferent fiber in cat sural and tibial nerves. Fiber activity was recorded distally with microneurography needle electrodes and proximally with hook electrodes. Records from the hook electrodes allowed the waveform shape and latency following natural stimulation to be compared with that produced by electrical stimuli delivered through the needle electrode. The action potentials from approximately 50% of the recorded fibers failed to propagate beyond the needle electrode. When propagation did occur and the comparison could be made, only 25% of the afferents recorded could be selectively stimulated. This relatively low success rate suggests that a typical microneurography needle is not particularly good for selectively stimulating identified afferents. Thus in human experiments, attempts to microstimulate identified afferents may often include stimulation of unidentified alternative, or additional, afferent fibers at thresholds of sensory perception.
Altered blood rheology in the pathogenesis of diabetic and other neuropathies
Authors: Simpson Leslie O. 
Published: January 2005

AbstractAlthough a substantial literature confirms the abnormal flow properties of diabetic blood, only in a few papers has the vasculitis of diabetic neuropathy been considered to have a hemorheological cause. It is proposed that the pathogenesis of nerve lesions involves an interaction between the specialized nerve vascular system and focal ischemic lesions resulting from rheologically induced stasis. The proposition is extended into other conditions with abnormal blood rheology such as hypothyroidism, uremia, dysglobulinemia, polyarteritis nodosa, and lepromatous leprosy. It is concluded that the treatment of such polyneuropathies should include an agent which would improve the flow properties of the blood.
EMG computerized analysis of localized fatigue in duchenne muscular dystrophy
Authors: Frascarelli Massimo , Rocchi Letizia , Feola Isidoro 
Published: January 2005

AbstractEMG power spectra obtained during a sustained isometric contraction were analyzed in a group of 10 children affected by Duchenne muscular dystrophy (DMD) and compared with those obtained in a control group of 5 normal children. In myopathic subjects the isometric contraction caused an increase of the total power, a progressive increase of power of the lower frequencies, a decrease of that of the higher frequencies, and a shift downward of the median frequency. In normal children an increase of the total power without a significant median frequency shift was noted.The modifications observed in DMD children were explained by a decrement of the firing rate of the more damaged fast twitch motor units. This decrease was probably induced by a relative predominance of activity of the slow twitch motor units, which are less damaged by the pathological process.
Linkage studies in facioscapulo‐humeral muscular dystrophy
Authors: Padberg George W. , Klasen Eduard C. , Volkers Willem S. , De Lange Gerda G. , Wintzen Axel R. 
Published: January 2005

AbstractPossible linkage between the locus for autosomal dominant facioscapulohumeral muscular dystrophy and the locus for the constant region of the heavy chains of the IgG immunoglobulins (Gm) was tested in 1 kindred (23 affected and 18 unaffected sibs) using the polymorphic DNA probe D14S1, which is known to be closely linked with Gm. No linkage between the loci for the disease and the probe was found, and the lod scores suggested that the locus for facioscapulohumeral muscular dystrophy is not situated on the distal part of the long arm of chromosome 14.
HLA‐DR‐expressing cells and T‐lymphocytes in sural nerve biopsies
Authors: Schrøder Henrik D. , Olsson Tomas , Solders Gäran , Kristensson Krister , Link Hans 
Published: January 2005

AbstractThirty‐five sural nerve biopsies were stained immunohistochemically for HLA‐DR antigen. HLA‐DR was expressed on nonmyelinating Schwann cells, macrophages, vascular endothelium, and perineurium. By means of double immunofluorescence staining the identity of the HLA‐DR presenting structures was confirmed. HLA‐DR expression was found in all biopsies and thus was not restricted to any particular type of neuropathy. The HLA‐DR expression appeared to correlate with severity and activity of the neuropathy. HLA‐DR‐expressing macrophages wrapping myelinated fibers were prominent in primary demyelinating neuropathies. T‐cells were found in 6 out of 15 nerves examined. Their presence correlated with moderate to strong HLA‐DR expression of nonmyelinating Schwann cells, and they occurred during active disease.
AAEE minimonograph #30: Electrophysiologic studies of myoclonus
Authors: Shibasaki Hiroshi 
Published: January 2005

AbstractDefinition as well as classification of myoclonus and electrophysiologic methods for investigating myoclonus were reviewed. Among the electrophysiologic techniques currently available in most laboratories, the EEG‐EMG polygraph is the most essential one and can provide us with the most important information. Jerk‐locked averaging and evoked potential studies are useful for further investigating the pathophysiology of myoclonus and can be performed by using the same recording electrodes as those used for the polygraph. Jerk‐locked evoked potentials and double‐stimulation evoked potentials can be employed only for further investigating how cerebral cortex is involved in the generation of certain myoclonia. All these techniques can be used in proper combinations depending on the clinical features of the myoclonus in question, the purpose of the study, and the facilities available in each laboratory. These techniques also will be useful for following the clinical course during the treatment with antimyoclonus agents.
Conduction studies in peripheral cat nerve using implanted electrodes: II. The effects of prolonged constriction on regeneration of crushed nerve fibers
Authors: Krarup Christian , Loeb Gerald E. , Pezeshkpour Gholam H. 
Published: January 2005

AbstractArrays of chronically implanted electrodes were used to examine the time course of elongation and maturation of peripheral nerve fibers in the cat after crush of the tibial nerve in the proximal calf. Regeneration after crush alone was compared with crush 5 mm proximal to a tight constriction of the nerve. Regeneration was monitored by the progression of excitability along the electrode arrays on the tibial and plantar nerves. The sensitivity was sufficient to record the averaged activity in single nerve fibers allowing detection of the earliest regeneration. The diameters of the fastest regenerating fibers were estimated from the conduction velocity proximal to the site of crush. Both after crush alone, and after crush constriction, small myelinated fibers regenerated in front of large fibers. The rate of elongation after crush alone was 3.2 mm/day, whereas it was slower (P < 0.02) distal to crush + constriction (2.2 mm/day). In both lesions, the extrapolated delay to onset of regeneration was 8 days. In observations up to 300 days after crush, maturation was delayed or impaired by the constriction, and the compound nerve action potential had a smaller amplitude and a dispersed shape. Transverse sections of nerves after crush + constriction showed a diminished number of large and an increased number of small fibers compared with crush alone, possibly due to persistent branching of regenerated fibers. After both crush alone and crush + constriction, regenerated fibers had similar g ratios, suggesting that myelination developed fully in fibers of diminshed diameters.
Muscular dystrophy in a litter of golden retriever dogs
Authors: Kornegay Joe N. , Tuler Sheila M. , Miller Doris M. , Levesque Donald C. 
Published: January 2005

AbstractClinicopathologic findings from two golden retriever dogs with an inherited, progressive, degenerative muscle disease that were studied until 27 and 40 months of age are described. Initial clinical signs included stilted gait and simultaneous advancement of their pelvic limbs. Further gait restriction and muscle hypertrophy eventually occurred. Serum creatine kinase was dramatically elevated (>10,000 U/L). There were persistent “spontaneous” high‐frequency discharges (pseudomyotonia) on electromyographic evaluation. Features of both muscle fiber degeneration (hyaline fibers, myophagocytosis) and regeneration (small basophilic fibers) were seen on light microscopy. Similar ultrastructural changes (fiber hypercontraction, increased myoblasts) were present. On morphometric histochemical evaluation, mean fiber diameter of both type 1 and 2 fibers was increased compared with controls in two of three muscles examined. There was no apparent fiber type predominance. Scattered ragged red fibers were seen, but this appeared to be a nonspecific finding of either muscle fiber regeneration or degeneration. These findings and potential contributing pathophysiologic mechanisms are discussed in relation to Duchenne muscular dystrophy.
Relationship of age and sex to sensory conduction of the median nerve at the carpal tunnel and association of slowed conduction with symptoms
Authors: Nathan Peter A. , Meadows Kenneth D. , Doyle Linda S. 
Published: January 2005

AbstractA cross‐sectional study of 471 randomly selected employees from 4 industries was performed to assess the prevalence of slowing of sensory conduction of the median nerve at the carpal tunnel as well as the effect of age and sex on slowing. The association between slowed conduction and symptoms of carpal tunnel syndrome (CTS) was also evaluated. Slowing was identified in 17% of the subjects and in 11% of the hands. The prevalence and the severity of slowing increased with increasing age of the subjects. Slowed conduction occurred more often among the women in the study, but this was shown to be an effect of age and not of sex. Slowing occurred six times more often in hands with symptoms of CTS than in those not reporting symptoms.
Use of motor units in relation to muscle fiber type and size in man
Authors: Jakobsson Finnbogi , Borg Kristian , Edström Lars , Grimby Lennart 
Published: January 2005

AbstractThe use of the musculus tibialis anterior during walking and the type and size of its muscle fibers were determined in 15 young normal subjects (29 ± 4 years) and in 13 old healthy subjects (70 ± 3 years). In the average step cycle 16 ± 6% of the maximal surface EMG was recorded during the swing phase and 44 ± 15% during 100 msec at the heel strike. Single motor unit recordings showed that low‐ threshold units fired at 10–15 Hz during the swing and at 20–25 Hz during the heel strike peak. Usually, high‐threshold units did not participate in the ordinary step cycle. A significantly higher mean use was found in the old subjects as compared with the young ones presumably due to lower muscle power in relation to body weight. In the young subjects 76 ± 7% of the muscle fibers were type 1 and 22 ± 7% were type 2A. In the old subjects 84 ± 9% were type 1 and 15 ± 8% were type 2A. In the young subjects the mean cross‐sectional area of type 1 fibers was 3950 ± 950 μm2 and of type 2 fibers was 8070 ± 1850 μm2. In the old subjects the corresponding numerals were 4050 ± 890 μm2 and 5700 ± 1970 μm2, respectively. The significance of physiological variations in use for muscle fiber type composition and size is discussed.
Effects of excessive use of remaining muscle fibers in prior polio and LV lesion
Authors: Borg Kristian , Borg Jörgen , Edström Lars , Grimby Lennart 
Published: January 2005

AbstractTwenty‐three subjects with weakness of musculus tibialis anterior (TA) due to prior poliomyelitis (n = 19) or prior LV lesion (n = 4) were examined regarding the use of remaining TA motor units during walking and the consequences of long‐term overuse for the TA muscle fibers. Subjects with an excessive overuse exhibited almost only type 1 muscle fibers and with marked hypertrophy. Subjects who did not use remaining TA fibers because of too‐severe paralysis had a normal fiber type differentiation and fiber atrophy. The use of remaining TA motor units was correlated to the type 1 muscle fiber percentage (r = 0.69) and to the type 1 fiber size (r = 0.78). Identical changes were observed in subjects with prior poliomyelitis and in subjects with prior LV lesion and were, thus, not specific for poliomyelitis. The changes in fiber type composition may be explained by a transition of type 2 to type 1 muscle fibers in accordance with previously reported experimental transneuronal stimulation through inplanted electrodes in animals.
Denervation‐induced proliferative changes of triads in rabbit skeletal muscle
Authors: Salvotri Sergio , Damiani Ernesto , Zorzato Francesco , Volpe Pompeo , Pierobon Sandra , Quaglino Daniela , Salviati Giovanni , Margreth Alfredo 
Published: January 2005

AbstractProtein compositional and functional differences exist between longitudinal and junctional sarcoplasmic reticulum (SR) in relation to Ca transport and to Ca release. In light of this knowledge, we have reinvestigated the effects of denervation on SR of rabbit gastrocnemius, a predominantly fast muscle. Electron microscopy of 2‐weeks denervated muscle showed proliferation of transverse tubules (TT), forming junctional contacts with SR terminal cisternae (TC). At coincident periods, the yield of muscle microsomes was increased, and their fractionation by sucrose‐density centrifugation demonstrated a relative increase of heavy vesicles. Thin‐section electron microscopy of heavy SR from denervated muscle showed an increased number of vesicles containing calsequestrin (CS) as compared with control muscle. Electrophoretic analysis confirmed the relative decrease of Ca‐ATPase protein and the striking increase of CS both in total microsomes and in heavy SR vesicles. Calcium loading and Ca‐ATPase activity as well as the density of Ca‐ATPase protein were decreased to a similar extent (20–30%) in denervated muscle microsomes. Stimulation of Ca‐ATPase activity by Ca‐ionophore A23187 showed that the vesicles were tightly sealed. When probed by competitive ELISA with antibody to SR Ca‐ATPase from pure fast muscle, the Ca‐ATPase of denervated microsomes was found to be highly cross reactive. Cleveland's peptide maps of the Ca‐ATPase protein after partial digestion with S. aureus V8 protease also showed no significant change after denervation. Changes in cholesterol content and in the ratio of Mg‐ATPase to Ca‐ATPase activity of denervated muscle microsomes indicated a 4‐fold increase of TT protein, i.e., from about 3% to not more than 12% of total protein, at 2 weeks after denervation. All these changes were totally reversed upon reinnervation of muscle fibers, and the consequent muscle recovery, as obtained by nerve crushing instead of nerve sectioning. From these results, we conclude that denervated adult fast muscle, similarly to immature fast muscle, contains more junctional SR. However, the molecular and catalytic properties of the Ca‐ATPase are unaffected by denervation.
Calcium currents and asymmetric charge movement in malignant hyperpyrexia
Authors: Lamb Graham D. , Hopkinson Kenneth C. , Denborough Michael A. 
Published: January 2005

AbstractIn both control pigs and pigs susceptible to malignant hyperpyrexia (MH), the size of the calcium current (ICa) and the amount of asymmetric charge movement varied considerably between different gracilis muscle fibers but appeared to vary in parallel. The mean amount of both ICa and charge movement were slightly but significantly smaller in MH‐susceptible (MHS) muscle compared with normal muscle. Halothane (1% v/v) reduced both parameters by almost 50%. One interpretation of the data is that the signal, which couples depolarization to calcium release from the sarcoplasmic reticulum, is abnormal in MHS muscle.
Delayed‐onset muscle damage and lipid peroxidation in man after a downhill run
Authors: Maughan Ronald J. , Donnelly Alan E. , Gleeson Michael , Whiting Paul H. , Walker Kim A. , Clough Peter J. 
Published: January 2005

AbstractLipid peroxidation initiated by free radical reactions is associated with tissue necrosis in a variety of conditions. We have measured serum lipid peroxide concentrations (as total thiobarbituric acid‐reactive substances, TBARS) and creatine kinase (CK), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) activities and subjective muscle soreness in 16 men before and after a 45‐minute downhill treadmill run. TBARS concentrations and enzyme activities were increased after exercise, with peak values observed at 6 hours (TBARS, LDH) or 24 hours (CK, AST) after exercise. Serum LDH activity returned to preexercise levels by 48 hours after exercise and TBARS by 72 hours after exercise: CK and AST activities remained elevated 72 hours after exercise. Leg mucle soreness also increased, with the greatest degree of soreness seen at 24 or 48 hours after exercise. Subjects with the greatest increase in CK, LDH, and AST also showed the highest serum TBARS concentration. This suggests a possible relationship between free radical generation and exercise‐induced muscle damage.