bluuebunny/crossref_metadata_2025 huggingface dataset:
Large delayed plasma creatine kinase changes after stepping exercise
Authors: Newham D. J. , Jones D. A. , Edwards R. H. T.
Published: January 2005

Muscle changes have been examined in 16 normal subjects (eight female) after both a 20‐minute and a prolonged step test. Stepping differs from most exercise tests in that it involves eccentric contractions (negative work) in which the active muscle is lengthened. Plasma creatine kinase (CK), muscle force, contractile properties, and tenderness in the quadriceps were measured for up to 9 days after the exercise. Muscle tenderness was experienced only in the muscles that had performed eccentric contractions (i.e., stepped down). All subjects showed some early rise in CK (<400 IU/liter) but eight (both male and female) showed a much greater response (up to 34,500 IU/liter) which took a long time to reach peak levels (4–5 days after stepping). It is suggested that eccentric contractions involved in this form of exercise result in some particular form of muscle damage which, in susceptible subjects, may initiate changes giving rise to a large delayed release of muscle enzymes.
Calmodulin content and Ca‐activated protease activity in dystrophic hamster muscles
Authors: Klamut Henry J. , Lin Chao Hsiung , Strickland Kenneth P.
Published: January 2005

As part of a study on the implication of elevated Ca2+ levels in the myofibrillar degeneration seen in dystrophic muscle, the content of calmodulin and the activity of Ca2+ ‐activated neutral protease (CANP) have been measured in normal and dystrophic (UM‐X7.1) hamsters. Calmodulin levels, expressed as micrograms ± SEM per gram wet weight were highest in brain (385 ± 24.7), followed by tongue (93.88 ± 3.93), heart (42.13 ± 2.93), and skeletal muscle (31.69 ± 1.42). No significant increases in calmodulin were observed in the dystrophic tissues thus suggesting that the Ca2+ accumulations observed in dystrophic muscles are unrelated to changes in calmodulin levels. Because of the complexity of regulation of CANP, a time‐dependent study was done using extracts of skeletal, heart, and tongue muscles. Marginal increases in dystrophic CANP were seen in skeletal muscle at all times studied and in the heart and tongue at initial time points only. The data are discussed in terms of rising levels of Ca2+ in muscles of the UM‐X7.1 hamster being sufficient to increase CANP activity (without increasing content) to where it causes Z‐line dissolution.
Effects of crush injury on the abnormalities in the spinal roots and peripheral nerves of dystrophic mice
Authors: Bray Garth M. , David Samuel , Carlstedt Thomas , Aguayo Albert J.
Published: January 2005

Lumbosacral spinal roots and peroneal nerves in dystrophic and control mice were crushed and allowed to regenerate. Six weeks after crush injury, the dystrophic roots no longer showed the typical groups of unensheathed axons that characterize the uncrushed roots. Thus, the location of this ensheathment defect in the spinal roots cannot be the exclusive mechanism responsible for its development. Crush injury and regeneration also tended to correct a second abnormality in the peripheral nervous system of dystrophic mice: the discontinuities in the Schwann cell basal laminas. Because the regenerated nerves contained increased amounts of collagen, the results of this study support the evidence from tissue culture experiments that the extracellular matrix may be involved in the pathogenesis of these disorders. However, the outcome of the present in vivo experiments indicates that genetically normal fibroblasts are not required for this change to occur.
Muscle pyruvate oxidation following denervation and reinnervation
Authors: Evans Owen B.
Published: January 2005

Muscle pyruvate metabolism was studied in rats following sciatic nerve crush. Control studies showed high pyruvate dehydrogenase and lipoamide dehydrogenase enzyme activity in muscle with type 1 fiber predominance (soleus) and low activities in muscle with type 2 fiber predominance (extensor digitorum longus), whereas lactate dehydrogenase was much higher in the latter. Following denervation, both muscles showed a significant reduction in pyruvate dehydrogenase enzyme activity. During reinnervation, muscle with type 2 predominance developed significantly elevated pyruvate oxidation enzyme activities.
Thickening of the human dorsal root ganglion perineurial cell basement membrane in diabetes mellitus
Authors: Johnson Peter C.
Published: January 2005

Lumbar dorsal root ganglia were sampled at autopsy from 27 diabetics and 22 nondiabetics. Using quantitative ultrastructural morphometry, the perineurial cell basement membrane thickness was estimated for each case, and a highly significant difference was found between the patient means for each group (nondiabetics 114 ± 18 nm vs. diabetics 203 ± 64 nm, P < 0.001). These results indicate that perineurial cell basement membrane thickening probably is present diffusely throughout the diabetic peripheral nervous system because it has been reported in the sural nerves and dermal nerves. The increased permeability of the blood‐nerve barrier of the dorsal root ganglia is apparently not a factor in the development of this basement membrane hypertrophy.
The neurotoxins 2,5‐hexanedione and acrylamide promote aggregation of intermediate filaments in cultured fibroblasts
Authors: Durham Heather D. , Pena Sergio D. J. , Carpenter Stirling
Published: January 2005

Axonal swellings associated with large aggregates of neurofilaments are characteristic of neuropathies caused by chemical neurotoxins (nhexane, methyl n‐butyl ketone, and acrylamide) or giant axonal neuropathy (GAN—an autosomal recessive genetic disease). In GAN, filamentous aggregates have been shown also to occur in other cell types including cultured skin fibroblasts. Therefore, we studied the effects of 2,5‐hexanedione (the neurotoxic metabolite of n‐hexane and methyl n‐butyl ketone) and acrylamide on normal human skin fibroblasts in tissue culture. We show that both neurotoxins induce aggregation of intermediate, filaments of the vimentin type in the cultured fibroblasts without disrupting microtubules.
Acetylcholinesterase molecular forms in C57BL/6J dystrophic mice
Authors: Lindenbaum Michael H. , Livett Bruce G.
Published: January 2005

Acetylcholinesterase (AChE) was extracted from normal and dystrophic C57BL/6J mouse hindlimb muscles and its molecular forms fractionated by sucrose density gradient ultracentrifugation. In the soleus muscles from 6‐ to 7‐week‐old mice an increase in the 3 Svedberg unit (S) and a decrease in the 16S AChE molecular forms was observed in dystrophic animals compared to controls. At 12–13 weeks of age, no major significant differences in the relative proportions of AChE molecular forms were noted. In the extensor digiorum longus (EDL) muscles of 6‐ to 7‐week‐old dystrophic mice a significant decrease in the proportion of the 10S AChE molecular form and an increase in the 3S and 5S forms was observed. At 12–13 weeks, the dystrophic EDL muscles again displayed a decrease in the 10S form; however, the increase in the 3S and 5S AChE forms, while still apparent, was not significant. These results provide evidence for a biochemical abnormality in the distribution of specific AChE molecular forms, and a differential expression of this abnormality in the soleus and EDL muscles.
AAEE case report #8: The tarsal tunnel syndrome
Authors: Delisa Joel A. , Saeed Mohammad A.
Published: January 2005

Tarsal tunnel syndrome is relatively rare and the diagnosis may be difficult even though the etiologies for the syndrome are multiple. The symptoms are often vague but are usually burning pain and paresthesias in the toes and soles of the feet with nocturnal exacerbations. The physical examination may elicit a sensory deficit over the cutaneous distribution of the median and/or lateral plantar nerve. There may also be tenderness over the flexor retinaculum. Electrodiagnosis, especially with the addition of the orthodromic compound nerve action potential latency technique, is essential to confirm the diagnosis. The findings may be confined to the distribution of either the medial or lateral plantar nerves and, thus, both distal latencies must be determined. Surgical decompression of the tarsal tunnel has usually proven to be helpful in those patients who do not respond to conservative treatment.
Neuromuscular disorders in a new toxic syndrome: Electrophysiological study—a preliminary report
Authors: Martínez A. Cruz , Conde M. C. Pérez , Ferrer M. T. , Cantón R. , Téllez I.
Published: January 2005

The electrophysiological features in 145 patients with a new toxic syndrome related to ingestion of adulterated oil are described. Myalgia, joint limitation, weight loss, cramps, progressive weakness and wasting, sensory disturbances that can be asymmetrical or patchy, and scleroderma‐like changes were the main clinical features. The electrophysiological findings suggest that the neuromuscular impairment in the new toxic syndrome is a slowly progressive mixed axonal neuropathy, which starts asymmetrically in some patients, with involvement of proximal and distal muscles as well as paraspinal and respiratory muscles. Muscle and nerve biopsies confirm the neuropathy, and show severe perineuritis and perineurial and perimysial fibrosis. The single fiber electromyography (SFEMG) study showed increased motor unit fiber density directly related to the time after onset of the illness. Unstable complex potentials were found after 6 months of evolution, which suggests that can effective collateral reinnervation was delayed following a long period of progressive denervation.
Reduced acetylcholine sensitivity in dystrophic mouse myotubes in vitro
Authors: Cossu Giulio , Eusebi Fabrizio , Molinaro Mario
Published: January 2005

Acetylcholine (ACh) sensitivity in cultured myotubes from normal or dystrophic mice was investigated using conventional techniques. Dystrophic multinucleate myotubes were found to be less responsive to the ACh with respect to the control preparation. Such a reduced sensitivity to ACh in dystrophic myotubes was accompanied by a reduced binding to125I‐alpha‐bungarotoxin. The possible biological significance of these results on the muscle disease is discussed.
Focal inflammatory myopathy
Authors: Lederman Richard J. , Salanga Virgilio D. , Wilbourn Asa J. , Hanson Maurice R. , Dudley Alden W.
Published: January 2005

We report three patients with inflammatory myopathy who presented clinically with weakness and wasting of only one limb. The myopathy progressed over 6 months and 5 years, respectively, in two patients and was stable after 8 years in the third patient. One patient had a skin rash. Serum CK was elevated in the two patients with progressive disease. Electromyography showed brief duration, small amplitude motor unit potentials and fibrillations in the affected limbs. Muscle biopsy revealed variable fiber size, degenerating and regenerating fibers, and inflammatory foci. Vasculitis was seen in the patient with skin lesions and marked fibroblastic proliferation in the patient with the most chronic course. Immunosuppressive therapy has arrested the progression in the two patients treated; both have regained strength.
Regulation of sarcomere number in skeletal muscle: A comparison of hypotheses
Authors: Herring Susan W. , Grimm Arthur F. , Grimm Betsy R.
Published: January 2005

Sarcomere lengths from 16 locations in the muscles of mastication were measured from pigs fixed in maximum excursion (wide jaw opening) and in postural position (near occlusion). These data, plus published data on sarcomere lengths in rabbit jaw muscles, were used to evaluate conflicting hypotheses about the factors which regulate serial sarcomere number in striated muscles. According to the most successful hypothesis, sarcomere number is adjusted so as to achieve an optimum sarcomere length when the muscle is experiencing a high level of tension. Most often, this occurs at jaw positions where the muscle is electrically active.
The effects of chronic muscular activity on age‐related changes in single fiber electromyography
Authors: Shields Robert W. , Robbins Norman , Verrilli Albert A.
Published: January 2005

Single fiber electromyography (SFEMG) of the extensor digitorum communis (EDC) muscle and nerve conduction studies were performed on healthy, active elderly men (66–77 years old) to assess age‐related changes in neuromuscular physiology and the effect of long‐term increased muscular activity on these changes. The following two groups were studied: a control group and a group composed of men with occupationally greater usage of hand extensors. Fiber density and mean jitter were essentially the same in both groups; however, in the hand‐user group there was greater variability in mean jitter and a significant increase in the prevalence of potential pairs with increased jitter or blocking. In both groups, slower nerve conduction velocities and lower amplitudes of sensory and motor evoked potentials tended to correlate with increased jitter and fiber density. These electrophysiological changes in healthy aged men are consistent with an extremely mild process of nerve terminal denervation and reinnervation. Although long‐term increased synaptic activity did not greatly alter the rate or extent of this process, it did produce a higher incidence of abnormal potential pairs and greater variability in mean jitter.
Abnormal use of remaining motor units during locomotion in peroneal palsy
Authors: Grimby Lennart , Holm Kerstin , Sjöuström Lars
Published: January 2005

The firing properties of single anterior tibial motor units were studied (during walking) with electromyogram (EMG) techniques in five normal subjects and in 10 patients who had footdrop due to an acute lesion of the common peroneal nerve. In the normal subjects, high threshold units did not fire in the ordinary step cycle and low threshold units fired at 10–25 Hz. In half of the paralyzed subjects, all motor units fired at 40–50 Hz for more than 200 msec in each step cycle, which could be sufficient for maximal force. In the other half of the paralyzed subjects, high threshold units were not reruited in each step cycle and low threshold units fired at 15–35 Hz, indicating that there were force reserves which were not used to prevent footdrop in each stride.
Rabbit sural nerve responses to chronic treatment with thalidomide and supidimide
Authors: Schwab Bradley W. , Arezzo Joseph C. , Paldino Albert M. , Flohe Leopold , Matthiessen Theo , Spencer Peter S.
Published: January 2005

Chronic treatment of rabbits with thalidomide (3‐(N‐phthalimido) glutarimide) produced progressive decrements in sural nerve conduction velocity (NCV) that were unassociated with qualitative or quantitative morphological changes of nervous tissue. Three groups of eight rabbits received 100 mg/kg/day thalidomide (group I), 200 mg/kg/day supidimide (a related drug) (group II), or a carboxymethylcellulose vehicle (group III) 5 days/week for 40 weeks. At 6 months of treatment, a noninvasive determination of the mean maximum sural NCV for group I was significantly reduced relative to the conduction velocities of groups II and III. Direct measurement of conduction velocity when treatment was terminated confirmed these findings and demonstrated similar conduction deficits in proximal and distal portions of the sural nerve in group I animals. At 6 months, rabbits in group II showed a significant reduction in mean conduction velocity, and, at the termination of treatment, they displayed mean values similar to that of group III and significantly greater than that of group I. Morphological findings were unremarkable in 20 regions of the central nervous system (CNS) and the peripheral nervous system (PNS) known to display changes early in toxic neuropathies. Morphometric estimation of unmyelinated and myelinated fibers in the sural nerve at the heel revealed no between‐group differences in axon diameter, fiber diameter, g‐ratio (the ratio of inside/outside diameters), or internodal length. In conclusion, chronic treatment with thalidomide produces selected decrements in sural nerve function that have an unknown relationship to the poorly reversible sensory neuropathy reported in humans receiving this drug.
Excretion of total and muscular Nτ‐methylhistidine and creatinine in muscle diseases
Authors: Röuthig H.‐Jürgen , Bernhardt Wolfgang , Afting Ernst‐Günther
Published: January 2005

The daily urinary excretions of Nτ‐methylhistidine and creatinine from 52 adult patients were measured under standardized conditions. The ratio of Nτ‐methylhistidine to creatinine excretion was calculated on the basis of the total and muscle‐specific excretion rates and correlated to the clinical status of the patients. In patients with muscular diseases and in those with diseases of the central nervous system, the total daily excretion of both metabolites was about 30% lower than in controls. The muscle‐specific ratio in patients with diseases of the central nervous system and patients with muscular diseases was not different from that observed in controls. Only in patients with neurogenic atrophies was the ratio elevated, so that it was more than twice the control value. The ratio of excreted Nτ‐methylhistidine/creatinine is only valid as an indicator of myofibrillar protein breakdown after correction for the contribution of nonskeletal muscle tissues to the urinary excretion.
Regenerative capability of skeletal muscle in chicken muscular dystrophy
Authors: Nonaka Ikuya , Fujita Takehisa , Sugita Hideo
Published: January 2005

To examine the morphological sequence of regenerating fibers after myonecrosis in dystrophic muscles, 0.5 ml of 0.5% bupivacaine hydrochloride (BPVC) (Marcaine) solution, a local anesthetic with a cytotoxic effect on the muscle fibers, was injected directly into the dystrophic (line 413) and nondystrophic (line 412) posterior latissimus dorsi (PLD) muscles of young and adult chickens. Although the dystrophic muscles after BPVC injection showed a rapid recovery with a similar tempo to that of nondystrophic ones, they showed different morphological behavior in the early phase of regeneration, including marked variability in the size of fibers and in the intracytoplasmic enzyme activities of nicotinamide adenine dinucleotide, reduced‐tetrazolium reductase (NADHTR), acetylcholinesterase (AChE), and nonspecific esterase (NSE).
Contractile and fatigue properties of thyrotoxic rat skeletal muscle
Authors: Fitts Robert H. , Brimmer Cheryl J. , Troup John P. , Unsworth Brian R.
Published: January 2005

The effects of thyrotoxicosis on the contractile properties and development of muscle fatigue in the slow soleus (SOL) and fast extensor digitorum longus (EDL) muscles were examined in rats given 3 mg of L‐thyroxine and 1 mg of L‐triiodothyronine per kilogram of diet for 6 weeks. The hormone treatment produced significant decreases in the contraction time, one‐half relaxation time, and twitch tension in the SOL, while the peak rate of tension development (+ dP/dt) and decline (− dP/dt) in this muscle were elevated. Additionally, the forcefrequency curve was shifted to the right and, thus, resembled the curve of a normal fast‐twitch muscle. In contrast, the contractile properties of the fast EDL were relatively unaltered by the hormone administration. Thyrotoxicosis also changed the SOL response to contractile activity as twitch tension, + dP/dt, and − dP/dt remained high, and a faster decline in muscle glycogen and an increase in lactate occurred compared to control muscles. These results clearly demonstrate a preferential effect of thyroid hormone on slow compared to fast skeletal muscle.
Clinical investigation in duchenne muscular dystrophy: IV. Double. Blind controlled trial of leucine
Authors: Mendell Jerry R. , Griggs Robert C. , Moxley Richard T. , Fenichel Gerald M. , Brooke Michael H. , Miller J. Philip , Province Michael A. , Dodson W. Edwin ,   CIID GROUP
Published: January 2005

Ninety‐six patients with Duchenne muscular dystrophy (DMD) were randomized and placed either on placebo or oral leucine at a dose of 0.2 g per kg per day. Patients were evaluated using a protocol that measured muscle strength, joint contracture, functional grade and activity, and pulmonary function tests. After 1 month there was a transient but significant difference in the strength of the two groups, the treated group being stronger than the placebo group. At 6 months there was also a transient difference in joint contracture measurements. Analysis of the data showed that the difference between the groups for both these measurements could not be ascribed to a therapeutic effect of leucine but rather to an unexpected drop in the placebo group. This was recognized only because the slope of deterioration for these functions had been well documented during the natural history phase of the study. These results indicate that oral leucine failed to produce a therapeutic response over a 1‐year double‐blind, controlled trial.
Electrodiagnostic tests in the detection of malignant hyperthermia
Authors: Eng Gloria D. , Becker Matthew J. , Muldoon Sheila M.
Published: January 2005

Malignant hyperthermia (MH) can be a catastrophic and sometimes fatal reaction in certain susceptible individuals who are exposed to skeletal muscle relaxants such as succinylcholine and/or certain inhalation anesthetics such as halothane. In an attempt to develop a safe, simple in vivo test to identify the at‐risk patients, repetitive nerve stimulation (RNS) and electromyographic (EMG) studies were performed on 9 patients with MH, 15 patients suspected of having MH, and 9 control subjects. Serial recordings were made following injections of caffeine sodium benzoate, succinylcholine, and halothane at the test site. Measurements were done on the amplitude of the evoked compound motor action potentials (CMAP), on RNS, and on the number of negative peaks of motor unit potentials (MUP) on maximum EMG recruitment. The results showed the effects of the drugs on amplitudes of the CMAPs to be significant (P < 0.001) in all three groups, but no significant differences were found among the groups (P = 0.93). The negative peaks of MUP on EMG recording showed a significant difference upon introducing succinylcholine (P < 0.001), and significant interaction effects of the treatment by the patient group. Preliminary comparisons of in vivo tests with in vitro contracture tests in nine patients showed good correlation.
Unimpaired energy metabolism in experimental neuropathy induced by p‐bromophenylacetylurea
Authors: Brimijoin Stephen , Mintz Keith P.
Published: January 2005

The contribution of defective energy metabolism to the induction of neuronal pathology by p‐bromophenylacetylurea (BPAU) was examined in several ways. It was found that a saturated aqueous solution of BPAU had no effect on the activity of crystalline glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) or phosphofructokinase (PFK). In rats with total hindlimb paralysis from treatment with BPAU (400 mg/kg), the endogenous GAPDH and PFK of sciatic nerve showed normal activity. Endogenous enolase and nerve‐specific enolase activities were likewise unaffected. Consequently, it appeared improbable that BPAU neuropathy involves impaired glycolysis. This conclusion was supported by the failure to prevent hindlimb weakness by feeding pyruvate, a substrate for the Krebs cycle. To test for interference with glycolysis at other steps, or for an impairment in oxidative phosphorylation, adenosine triphosphate (ATP) and creatine phosphate were measured. The amounts of high energy phosphates in nerves of paralyzed animals were found to be the same as in nerves of untreated and vehicle‐treated controls. A similar observation was made in nerves regenerating from a crush injury. To test turnover, ATP and creatine phosphate were measured in nerves exposed to an N2 atmosphere in vitro. Since the high energy phosphates disappeared at the same rates in all groups, it was concluded that BPAU neuropathy does not alter energy utilization. In our view, BPAU neuropathy arises by a mechanism that does not depend on altered energy metabolism.
Use of mononuclear precursor cells to insert allogeneic genes into growing mouse muscles
Authors: Watt Diana J. , Morgan Bsc Jennifer E. , Partridge Terence A.
Published: January 2005

Our long‐term aim is to use allografts of normal muscle precursor cells to insert donor myonuclei, containing a normal genome, into the growing defective muscle fibers of young animals with inherited myopathies. In the present article, we have used isoenzyme variants of glucose‐6‐phosphate isomerase (GPI) as genetic markers of host and donor genomes in the mouse. We show that mononucleated cells, prepared by enzymatic disaggregation of neonatal donor muscle,39 can be used to introduce donor GPI genes into muscle fibers of growing muscles of young hosts. The expression of both donor and host GPI genes in the resulting mosaic muscle fibers leads to the formation of a “hybrid” GPI isoenzyme dimer. Such hybrid GPI was found in 10 of 102 host muscles examined. Our results indicate that grafts of muscles precursor cells can be used to alter the genetic constitution of both normal and mildly myopathic muscle.
Potassium depletion myopathy: A clinical and morphological study of six cases
Authors: Comi G. , Testa D. , Cornelio F. , Comola M. , Canal N.
Published: January 2005

Acute myopathy in conditions associated with endogenous or druginduced potassium loss has been reported. We describe six patients with potassium depletion myopathy (P‐DM). The clinical picture included flaccid muscle weakness without sensory loss, myalgia, polyuria, and polydipsia. All the cases had markedly increased serum creatine kinase (CK) levels. The most consistent pathological characteristics were phagocytosis of degenerating muscle fibers plus fiber regeneration. Atrophy of type 2 fibers was observed. Vacuoles and vesicular elements originating from T‐tubules were also encountered. The clinical manifestations and morphological changes had reversed after potassium repletion. Both constriction of vascular smooth muscle and cellular energy failure may be pathogenetic factors in P‐DM.
Clinical investigation in Duchenne Dystrophy: V. Use of creatine kinase and pyruvate kinase in carrier detection
Authors: Griggs Robert C. , Mendell Jerry R. , Brooke Michael H. , Fenichel Gerald M. , Miller J. Phillip , Province Michael , Moxley Richard T. , Huntzinger Donna , Vaughn Arthur , Cohen Melinda , Conneally P. Michael , Bach Phillip ,   CIDD Group
Published: January 2005

We have determined the value of creatine and pyruvate kinase (CK and PK) in carrier detection by evaluating 811 females in 73 families participating in the Collaborative Investigation of Duchenne Dystrophy. Thirty‐nine obligate carriers, 244 normal controls (paternal females), as well as 76 possible carriers and 351 carrier suspects had three CK and PK specimens analyzed at a central laboratory. The CK and PK values varied with age in normals: both fell with age early in life, and CK rose after the fifth decade. Discriminant analysis indicated that the combination of mean CK and PK corrected for age yielded the best data for calculation of carrier probability. Using the best model, only 45% of obligate carriers could be identified at a false‐positive rate of 2.5%. Daughters of obligate carriers have a disproportionate decline in CK and PK with age as compared to noncarrier females, suggesting that the rate of carrier detection will be higher in the first two decades. Our low rate of carrier detection, as compared to other studies, may reflect both the age of our obligate carrier population and the use of a control group that is more representative of the carrier population.
Basic polyaminoacids and protamine stimulate enzyme release from frog muscles
Authors: Suarez‐Kurtz Guilherme
Published: January 2005

Polylysines, polyornithine, and protamine increased the release of creatine kinase (CK) and lactate dehydrogenase (LDH) from frog muscles. With 5 m̈g/ml (50 nM) of a polylysine of molecular weight 100,000, enzyme release reached peak values (ten‐fold above control) within 30 minutes; subsequent removal of the polylysine did not reduce significantly the release rates. The effectiveness of the polycations increased with the degree of polymerization. Their effects were prevented by pretreatment of the muscles with polyanions (heparin or polyglutamic acids) and were reversed when heparin was applied within 30 minutes of exposure to polylysine. The initial stimulation of enzyme release by polylysine was attenuated by Ca‐free solutions and by low temperature (4°C). It is suggested that, while fiber damage can explain the increased loss of sarcoplasmic enzymes after prolonged treatment of frog muscles with polycations, other mechanisms (perhaps exocytosis) are involved in the stimulation of CK and LDH release during brief exposures to nanomolar concentrations of polylysines or polyornithine.
The effects of inspiratory resistive training on respiratory muscle function in patients with muscular dystrophy
Authors: DiMarco Anthony F. , Kelling James S. , DiMarco Marianne Sajovic , Jacobs Irwin , Shields Robert , Altose Murray D.
Published: January 2005

The effects of inspiratory resistive training on respiratory muscle function was evaluated in 11 patients with Duchenne, limb‐girdle, and facioscapulo‐humeral (FSH) type muscular dystrophy. Muscle training consisted of breathing against an inspiratory resistance for two 15‐minute sessions each day while at home. Following 6 weeks of training, there were significant increases in the maximum resistance that could be tolerated for at least 5 minutes (P < 0.01) and also in the maximum duration that ventilations equal to 30%, 50%, 70%, and 90% of the maximum voluntary ventilation could be sustained (P < 0.05). In six patients who trained for an additional 6‐week period, respiratory muscle endurance increased even further. The degree of improvement in respiratory muscle endurance was positively correlated with baseline vital capacity (r = 0.84, P < 0.05) and maximal inspiratory pressure (r = 0.76, P < 0.05). Spirometry, functional residual capacity, and maximal inspiratory and expiratory pressures were not affected by training. We conclude that inspiratory resistive training improves respiratory muscle endurance in muscular dystrophy patients. Improvement in respiratory muscle function may serve to delay the onset of respiratory complications in patients with muscular dystrophy.
Intracellular ionized calcium concentration in muscles from humans with malignant hyperthermia
Authors: López José R. , Alamo Lorenzo , Caputo Carlo , Wikinski Jaime , Ledezma David
Published: January 2005

Ca2+ selective microlectrodes have been used to determine the free myoplasmic [Ca2+] in human skeletal muscle obtained from patients who had developed early signs associated with malignant hyperthermia (MH) during anesthesia. Intercostal muscle biopsies were performed under local anesthesia in four MH patients 15 days to 4 months after developing the MH crisis and in three control subjects. We used only microelectrodes that showed a Nernstian response between pCa3 and pCa7 (30.5 mV per decade at 37°C). Membrane resting potential (Vm) and calcium potential (VCa) were obtained from superficial fibers. The free cytosolic [Ca2+] was 0.39 ± 0.1 m̈M (mean ± SEM, n = 18) in muscle fibers obtained from malignant hyperthermic patients, whereas in control subjects it was 0.11 ± 0.02 m̈M (n = 10). These results suggest that this syndrome might be related to an abnormally high myoplasmic free resting calcium concentration, probably due to a defective function of the plasma membrane or the sarcoplasmic reticulum.
Computed tomography of the skeletal musculature in Becker‐type muscular dystrophy and benign infantile spinal muscular atrophy
Authors: De Visser Marianne , Verbeeten Bernard
Published: January 2005

Results of computed tomographic (CT) examination of the skeletal musculature in 26 patients with Becker‐type muscular dystrophy (BMD) and 12 patients with benign infantile spinal muscular atrophy (BISMA) are presented. Both disorders reveled strikingly different changes that may have important clinical significance. First, in BMD, CT abnormalities consisted of areas of decreased densities, at first appearing in part of the muscle, and then gradually spreading until the whole muscle was replaced by low‐density tissue. In BISMA, however, low‐density lesions were scattered throughout the muscle. Second, in BMD, some muscles were preferentially affected in an early stage of the disease and others were relatively spared, whereas in BISMA, the muscles were involved more or less simultaneously. Third, an enlargement in size (hypertrophy) was frequently observed in BMD in various muscles of the legs, whereas in BISMA, this phenomenon can sometimes be noted only in the gastrocnemius muscles.
Electrophysiology of the facial nerve in hemifacial spasm: Ectopic/ephaptic excitation
Authors: Nielsen Viggo Kamp
Published: January 2005

Pathologic and pathophysiologic findings in hemifacial spasm are reviewed in connection with recent theoretical and experimental studies of ectopic/ephaptic excitation. The intracranial segment of the normal facial nerve is ensheathed by an arachnoid membrane only and shows no fascicular organization. In hemifacial spasm, this segment shows signs of demyelination. Several electrical phenomena relating to ectopic excitation, ephaptic transmission between facial nerve fibers, and autoexcitation can be reproduced in clinical electrophysiologic studies of hemifacial spasm. These abnormalities gradually disappear after facial nerve decompression in the cerebellopontine recess. It is concluded that (1) the normal facial nerve is vulnerable to minor compression, (2) the primary pathophysiologic mechanism in hemifacial spasm is ectopic/ephaptic excitation due to compression and demyelination of the intracranial segment of the facial nerve, and (3) the facial nerve in hemifacial spasm is a useful model for the study of ephaptic transmission, which has provided new information about the resolution of abnormal electrical events after decompression.
Diagnostic advantage of needle muscle biopsy and ultrasound imaging in the detection of focal pathology in a girl with limb girdle dystrophy
Authors: Heckmatt J. Z. , Dubowitz V.
Published: January 2005

Ultrasound imaging of the thigh in a 6‐year‐old girl with limb girdle muscular dystrophy showed striking focal involvment of the vastus intermedius and vastus lateralis muscles, with sparing and hypertrophy of the rectus femoris muscle. This was confirmed on needle muscle biopsy, using the Bergstrom needle, which showed normal histology in the rectus femoris and severe dystrophic change in the vastus intermedius. In neuromuscular disease, it is important to be aware of the possibility of focal muscle involvement, which can be screened for by ultrasound imaging and more effectively investigated by needle than by open muscle biopsy.
Endogenous lectins in normal and dystrophic muscle development
Authors: Ceri Howard , Roberts Delia
Published: January 2005

Two endogenous lectin activities, one specific for b̃‐D‐galactose (b̃‐D‐Gal) residues and purified on asialofetuin‐Sepharose and the second specific for iduronic acid containing glycosaminoglycans and purified on heparin‐Sepharose, have been studied during myogenesis in both normal and dystrophic chickens. The Storrs strain, homozygous for muscular dystrophy, and the dystrophic strain 413 from the University of California at Davis were both used in this study. Strain 412 and local hatchery chickens were used as controls. The lectins derived from all sources appeared to be identical based on physical properties and carbohydrate specificity. Both normal and dystrophic adult chickens possessed similar lectin levels in lung, spleen, kidney, heart, and muscle tissue. No differences were noted in the temporal appearance of the heparin‐binding lectin; however, the b̃‐D‐Gal‐binding lectin appeared earlier in the Storrs dystrophic strain than it did in the 413, 412, or hatchery embryos.
Reversible esophageal motor dysfunction in botulism
Authors: Nix Wilfred A. , Eckardt Volker F. , Krämer Günther
Published: January 2005

Two cases of botulism with autonomic and neuromuscular system involvment are presented. In both patients, dryness of the mouth and difficulties in swallowing were predominant symptoms. Esophageal manometry revealed a marked decrease in peristaltic amplitude, which was most pronounced in the upper third of the esophagus. These functional abnormalities returned to normal following recovery from the acute disease.
The temperature dependence of halothane‐induced contractures of skeletal muscle
Authors: Suarez‐Kurtz Guilherme , Sudo Roberto T.
Published: January 2005

Frog muscles bathed in solutions equilibrated with 0.5%–2.0% halothane develop large contractures when cooled to 2–4°C. These halothane‐cooling contractures (HCC) are dose dependent and reproducible; they are potentiated by lidocaine (5 mM), abolished by procaine (5‐mM), and partially inhibited by procainamide (5 mM) or sodium salicylate (2 mM). The HCC provides a simple model system for investigating the effects of low halothane concentrations on Ca homeostasis and contractility in skeletal muscle.
The amino acid sequence of human cardiac troponin‐C
Authors: Roher Alex , Lieska Norman , Spitz Werner
Published: January 2005

The amino acid sequence of human cardiac troponin‐C (TN‐C) has been rabbit cardiac TN‐C. These results show that troponin‐C is one of the Edman degradation. The sequence, which consists of 161 amino acid residues is identical to that of the ox heart and as such is capable of binding three calcium ions. It differs at only one position from that of rabbit cardiac TN‐C. These results show that troponin C is one of the most highly conserved proteins known.
Dipeptidyl peptidase I in cultured fibroblasts in duchenne muscular dystrophy
Authors: Sinclair Christine E. , Ecob Marion S. , Pennincton Ronald J. T.
Published: January 2005

The specific activity of dipeptidyl peptidase I in cultured skin fibroblasts from patients with Duchenne muscular dystrophy did not differ significantly from that of controls.
Electrophysiologic assessment of a median nerve injury in the palm
Authors: Busis Neil A. , Logigian Eric L. , Shahani Bhagwan T.
Published: January 2005

In median nerve lesions of the hand, electrophysiologic evaluation of the second lumbrical muscle can help to differentiate between lesions of the common digital nerves and the proper digital nerves, as illustrated by this case report. Median nerve conduction studies to the second lumbrical muscle can be performed by placing an active recording electrode just radial to the midpoint of the third metacarpal and stimulating the median nerve at the wrist or elbow.
The contribution of median—ulnar communications in diagnosis of mild carpal tunnel syndrome
Authors: Gutmann Ludwig , Gutierrez Alvaro , Riggs Jack E.
Published: January 2005

In six patients with characteristic symptoms of carpal tunnel syndrome, electrophysiologic studies were normal, except for an initial positive deflection of the thenar muscle action potential with median nerve stimulation at the elbow but not at the wrist. This phenomenon is only seen with coexistent carpal tunnel syndrome and median to ulnar nerve communication and suggests carpal tunnel syndrome is present in these patients. As normal electrophysiologic studies occur in carpal tunnel syndrome (up to 8%) and median to ulnar communications are common (15%–31%), this observed finding is of practical clinical importance in the diagnosis of mild carpal tunnel syndrome despite otherwise normal electrophysiologic studies.
Transient focal conduction block following experimental occlusion of the vasa nervorum
Authors: Parry Gareth J. , Linn Diana J.
Published: January 2005

Injection of low‐dose arachidonic acid into the rat femoral artery occludes the vasa nervorum of the tibial nerve and produces focal and generalized ischemia with transient effects on nerve conduction. Across a severely ischemic segment of the proximal tibial nerve there is a marked fall in amplitude of the compound muscle action potential (CMAP), indicating focal conduction block. There is also significant slowing of maximal motor conduction velocity (MCV) through this nerve segment, but no dispersion of the proximally elicited response. Distally, in a region of less severe ischemia, there is mild slowing of MCV, but no further decrement in the CMAP amplitude. The conduction block begins 5–15 minutes after injection, reaches a nadir at 30 minutes, and persists in more severe cases for at least 2 hours. Despite these prolonged electrophysiologic abnormalities, there is no evidence of axonal degeneration or segmental demyelination.
Distribution of muscle changes in experimental ischemic myopathy
Authors: Maki Toshiyuki , Korthals Jan K. , Prockop Leon D.
Published: January 2005

The distribution of ischemic changes was examined in the medial gastrocnemius muscle of the cat, following transient simultaneous clamping of the aorta and femoral artery. Initial changes occurred in the middle portion of the muscle, in the areas corresponding to watershed zones of the primary arteries of the muscle. The superficial layers of the muscle, the regions close to the main stem of the primary arteries, and the entire distal portion of the muscle were the most resistant to ischemic damage. These studies demonstrate that in the feline medial gastrocnemius muscle, the vascular pattern is the primary factor in determining the distribution of ischemic changes. The role of differential muscle fiber vulnerability is only secondary.
IMP response: An indicator of metabolic stress in working muscle
Authors: Heller Scott L. , Choksi Rati , Brooke Michael H.
Published: January 2005

An in vitro system for the combined biochemical and physiologic analysis of striated muscle has been developed. It is hoped that its eventual application will be to the evaluation of human muscle disease. To test the method's usefulness in evaluating metabolic defects, we used iodoacetate to induce a glycolytic defect in animal muscle. This produced the expected effects of precipitous fatigue on repetitive stimulation, increased inosine monophosphate (IMP) and decreased adenosine triphosphate (ATP) and phosphocreatine; in addition, the severity of the glycolytic block was directly related to the amount of IMP produced per gram twitch tension.
Muscle morphology, enzymatic activity, and muscle strength in elderly men: A follow‐up study
Authors: Aniansson Amelie , Hedberg Marita , Henning Gull‐Britt , Grimby Gunnar
Published: January 2005

A follow‐up study of muscle strength, muscle morphology, and enzymatic activity in 23 men, 73–83 years of age, was performed 7 years after the first investigation. With the exception of two men treated for congestive heart failure and four treated for hypertension, all were apparently clinically healthy and none had functional locomotor disturbances. Body weight was reduced by 2% and body cell mass by 6%, whereas the quadriceps muscle strength decreased 10%–22% over the 7‐year period. Fiber composition in the vastus lateralis did not change significantly, and there was no significant difference between the biopsies from the biceps brachii and vastus lateralis. In the vastus lateralis, there was a reduction in fast‐twitch fiber areas, which were smaller than in the biceps brachii (not studied at the previous investigation). There were also more histopathologic changes in the vastus lateralis than in the biceps brachii. The enzymatic activities of lactate dehydrogenase and myokinase, which were studied on both occasions in the vastus lateralis, did not change, and the activities of the other measured enzymes indicated a maintained metabolic capacity at high age. Oxidative enzymatic activities were higher in the vastus lateralis, and glycolytic enzymatic activities were higher in the biceps brachii, which could partly be explained by differences in relative fiber areas.
A double‐blind, placebo‐controlled, crossover study of verapamil in exertional muscle pain
Authors: Lane Russell J. M. , Turnbull Douglass M. , Welch John L. , Walton John
Published: January 2005

Eleven patients, comprising three cases of McArdle's disease and eight with an exertional muscle pain syndrome (EMPS) of unknown cause, entered a double‐blind crossover study of verapamil and placebo. None of the patients with McArdle's disease responded to verapamil, but two patients with unclassified EMPS experienced a striking improvement in symptoms and two others showed a partial response. No patient responded to placebo. Six of the eight cases with unclassified EMPS, including the four patients who responded to verapamil, had symptoms that indicated possible abnormalities of muscle metabolism, and four showed nonspecific biochemical, electromyographic, and muscle biopsy abnormalities. The two other EMPS patients had symptoms that suggested that a primary muscle disease was unlikely. They showed no laboratory evidence of muscle disorder, but had abnormal profiles on personality (MMPI) testing. Calcium antagonists, such as verapamil, may be useful in the treatment of some patients with benign exertional myalgia, but the mechanism of action of the drug in such cases is unclear.
Classification of peripheral neuropathy: The long and the short of it
Authors: Sabin Thomas D.
Published: January 2005

Insights into how the nervous system functions have often sprung from knowledge of the localization of nervous system diseases. Indeed, the recent rebirth of behavioral neurology has been sparked by new insights into the topography of higher cortical functions. Yet, the localization of disease affecting the‐peripheral nervous system is simply assumed to be a by‐product of the beginning course in gross anatomy! Indeed, the anatomic sophistication laid out by Sunderland29 and reflected in the daily practice of electromyography might cause doubt as to the need for further inquiry into the problem of localization of disease within peripheral nervous system. There are, however, numerous problems in clinical practice that do not yield to the traditional root‐plexus‐nerve analysis of localization.
A quantitative comparison of satellite cell ultrastructure in duchenne muscular dystrophy, polymyositis, and normal controls
Authors: Watkins Simon C. , Cullen Michael J.
Published: January 2005

Failure of the muscle to regenerate successfully is an important feature of the pathology of Duchenne muscular dystrophy (DMD). It is known that this is not due to a numerical reduction in the population of satellite cells. We have therefore examined the ultrastructural composition of the satellite cells in 25 DMD cases and compared them with satellite cells from normal subjects and from polymyositis patients to try to identify morphological features that might be associated with an impaired developmental competence. Profiles of randomly and serially sectioned satellite cells were analyzed stereolgically to obtain nuclear and cytoplasmic areas. Within the cytoplasm, the areas occupied by mitochondria, rough endoplasmic reticulum (RER), and Golgi apparatus were measured. Micropinocytotic vesicles (MPVs) at the perïphery of the cells were counted. The nucleus to cytoplasm ratios and mitochondrial, RER, and Golgi volume fractions were not significantly different in the three satellite cell samples. The cells in the DMD sample contained more MPVs than those in the normal subjects. This is attributed to a generalized cell response to a physiologically altered environment in the diseased muscle.