bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental corticosteroid myopathy: Effect on myofibrillar ATPase activity and protein degradation
Authors: Clark Abbot F. , Vignos Paul J. 
Published: January 2005

AbstractCorticosteroid myopathy was studied in young, mature New Zealand white rabbits given daily injections of betamethasone (0.3 mg/kg body weight/day) for two weeks. Control rabbits were pair‐fed and received saline injections. Betamethasone treatment caused significant wasting of type 2 gluteus medius and psoas muscles but did not cause any atrophy of type 1 soleus and gluteus minimus muscles. The Mg2+‐ and Ca2+‐activated myofibrillar ATPase activities of the corticosteroid‐treated rabbits did not differ from controls despite a 30% reduction in muscle wet weight and pronounced reduction in cross‐sectional area of fibers. SDS‐polyacrylamide gel electrophoresis profiles of myofibrillar proteins did not differ quantitatively or qualitatively between experimental and control rabbits. Studies of net muscle protein degradation (using 3H‐leucine) in betamethasone‐treated and control rabbits indicate that both type 1 and type 2 muscle fiber proteins are degraded several times faster in the corticosteroid‐treated group. This suggests that a compensatory mechanism exists for those type 1 and mixed fiber type muscles which have increased degradation but do not undergo wasting.
Serum creatine kinase and pyruvate kinase in duchenne muscular dystrophy carrier detection
Authors: Percy Maire E. , Chang Lebe S. , Murphy E. Gordon , Oss Irina , Verellen‐Dumoulin Christine , Thompson Margaret W. 
Published: January 2005

AbstractThe incidence of elevated serum creatine kinase (CK) and pyruvate kinase (PK) activities was compared in 20 definite carriers of Duchenne muscular dystrophy (DMD), 47 possible carriers, and 42 female controls. When adult age was not regarded as a variable, 70% of the definite carriers had elevated PK, 55% had elevated CK, and 75% had elevated PK or elevated CK or both; 38% of the possible carriers had elevated PK, 19% had elevated CK, and 40% had elevated PK or elevated CK or both. The detection efficiency of the CK test was influenced by the age of the subjects: the upper normal limit of serum CK in the adult controls was at the minimum between 21 and 35 years of age, and CK activity in some carriers declined from elevated to normal levels with increasing age. With these considerations, 70% of definite carriers had elevated CK and 80% had elevated PK and/or CK; 34% of the possible carriers had elevated CK and 43% had elevated PK and/or CK. On the basis of the PK and CK measurements, only 16 of 24 possible carrier mothers were likely to be DMD carriers, implying that the other 8 were non‐carrier mothers of new mutant sons.
Split genes and muscular dystrophy
Authors: Lewis Robinson 
Published: January 2005

AbstractRecent developments in molecular biology have shown that some genes are split into segments, each coding for part of a protein. The intervening segments are transcribed but later excised, and the messenger RNA is spliced back together again before translation into protein begins. Abnormalities in the nontranslated segments would not be reflected in abnormal protein structure but, presumably, in the control of synthesis of a particular protein. The muscular dystrophies may be an example of this class of disease. They are particularly amenable to investigation of this idea because muscle produces large amounts of relatively few proteins, facilitating isolation of the appropriate messenger RNA.
Evoked responses of the elbow flexors in control subjects and in myopathy patients
Authors: Krarup Christian , Horowitz Steven H. 
Published: January 2005

AbstractElectrical and mechanical responses were evoked in the elbow flexors (EFs) of normal subjects and myopathy patients by maximal stimulation of the musculocutaneous nerve by a wire electrode in the axilla. In normals, the decrement in the mechanical responses during short trains of twitches was small (10%). The potentiation during a staircase decreased with increasing frequency of stimuli, but the potentiation 30 sec after the 100‐sec staircase was the same at all frequencies. Posttetanic potentiation was twice as large as the maximal potentiation attained during the staircase. The staircase phenomenon probably results from two opposing events, diminution and potentiation. Findings in 11 patients with myopathy varied according to the severity of involvement. Slight weakness of the EFs was associated with an increased twitch:tetanus ratio, decreased tetanic tension, and decreases in the staircase and posttetanic potentiation. Additionally, severe weakness of the EFs was associated with a diminution in twitch tension.
Animal models of peripheral neuropathy: The trembler mouse
Authors: McLeod J. G. , Low P. A. 
Published: January 2005

AbstractOne of the features of the IVth International Congress on Neuromuscular Diseases, held in Montreal September 17–21, 1978, was a series of invited posters. In order to achieve a wider audience for this valuable material, we have made arrangements to publish a number of these posters in Muscle & Nerve. This is the third poster in this series. To preserve the original effect of the posters, they are being reproduced almost exactly as they appeared at the Congress, without editing or other alterations. We hope you will find this feature a useful addition to your Journal.
Red blood cell and fibroblast membranes in Duchenne and myotonic muscular dystrophy
Authors: Roses Allen D. , Hartwig Geoffrey B. , Mabry Michael , Nagano Yasuho , Miller Sara E. 
Published: January 2005

AbstractThe literature concerning red blood cell and fibroblast protein studies in Duchenne and myotonic muscular dystrophy is critically reviewed. In this review, we emphasize methodological and technical considerations in order to promote an appreciation of the complexities of this area of research to clinical scientists interested in muscle disease.
Determinants of conduction velocity in myelinated nerve fibers
Authors: Waxman Stephen G. 
Published: January 2005

AbstractThis article reviews the determinants of conduction velocity in myelinated nerve fibers. For fibers exhibiting geometric similarity, conduction velocity is nearly proportional to diameter. However, in classes of geometrically similar fibers, myelin thickness and internode distance are linearly related to diameter. Therefore, it is not possible to assess the relative contributions of each of these factors. The relative effects of changes in each of these parameters on conduction velocity can be assessed from studies on fibers representing different similarity classes or from theoretical parametric studies. These studies show that for a fixed axon diameter, conduction velocity increases with myelin thickness. For a fixed total fiber diameter, there is an optimal ratio of axon diameter to total fiber diameter (and therefore to myelin thickness) at which conduction velocity is maximized. Conduction velocity is dependent on internode distance, with a broad maximum centered around the value observed in normal peripheral fibers. Conduction velocity is also dependent on temperature and the properties of the axonal milieu. Thus, the conduction speed of any given fiber reflects a number of parameters and is not determined by any single structural characteristic.
Centronuclear myopathy: Extraocular‐ and limb‐muscle findings in an adult
Authors: Bergen Barry J. , Carry Michael P. , Wilson W. Bruce , Barden Michael T. , Ringel Steven P. 
Published: January 2005

AbstractMyotube‐like structures were seen in extraocular and limb muscles in an adult with centronuclear myopathy. The limb‐muscle fibers were very small and were of a uniform histochemical type. Extrajunctional acetylcholine receptors were not seen with immunoperoxidase stains, and ultrastructurally normal neuromuscular junctions were seen in the extraocular‐muscle samples. Further studies on developing muscle are needed to identify possible mechanisms of arrest of muscle maturation.
Congenital insensitivity to pain with anhidrosis
Authors: Rafel E. , Alberca R. , Bautista J. , Navarrete M. , Lazo J. 
Published: January 2005

AbstractA nine‐year‐old child presented with congenital insensitivity to pain and anhidrosis. Quantitative studies and electron microscopy of the cutaneous branch of the radial nerve revealed almost complete absence of small myelinated and unmyelinated fibers and a disproportionate number of nerve fibers with a diameter of 6–10 μm. A grouping of both type 1 and type 2 muscle fibers was also seen. We suggest that this disease entity is not caused by a hereditary sensory neuropathy, but rather that it derives from a developmental defect.
Serum myoglobin in muscular dystrophy
Authors: Kagen Lawrence J. , Moussavi Shahla , Miller Stephanie L. , Tsairis Peter 
Published: January 2005

AbstractElevated levels of serum myoglobin (MGB) were found in patients with several types of myopathic disorders, namely, Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), facioscapulohumeral dystrophy, and limb‐girdle dystrophy. The frequency of hypermyoglobinemia was greatest in patients with DMD and BMD (91.7% and 100%, respectively). There was no precise direct relationship between serum creatine kinase (CK) and MGB levels, although the disorders with the highest CK levels tended to be the ones with the highest MGB levels. Among the patients with DMD, hypermyoglobinemia was slightly less marked in older children with restricted ability to walk than in the younger ones. Hypermyoglobinemia was noted among 43.8% of the mothers and 41.7% of the sisters of patients with DMD, slightly greater frequencies than for abnormal CK determinations in this group. Multiple serum samples were analyzed from 10 of these women, and the overall frequency of abnormal MGB levels was the same as that of abnormal CK levels; however, levels of CK and MGB were discrepant in some individual serum samples. For this reason, serum MGB determination may be a useful adjunct in the study of possible DMD carriers.
Echocardiography in duchenne muscular dystrophy
Authors: Danilowicz Delores , Rutkowski Monica , Myung Dong , Schievely Dora 
Published: January 2005

AbstractThe cardiac function of 36 males with Duchenne muscular dystrophy was evaluated by echocardiography, and the results were compared with the results of other tests of cardiac involvement, including serum creatine kinase isoenzyme evaluation, electrocardiography, chest x‐ray, and physical examination of the heart and lungs. Although correlation between the various methods of assessment was not impressive, the echocardiographic technique appeared to be useful in evaluating and following the cardiomyopathy in these patients. Several aspects of left ventricular function were abnormal in most patients, and only two of the 36 had normal left ventricular size and function. Electrocardiographic abnormalities were also apparent in all patients, although the changes were mild in four of the 36. Clinical evalution, isoenzyme determinations, and chest x‐rays have not been useful in assessing cardiac function. The echocardiographic data on these 36 patients are presented in detail and the patients will now be followed sequentially to attempt evaluation of ongoing changes.
Muscle reorganization after partial denervation and reinnervation
Authors: Peyronnard Jean‐Marie , Charron Louise 
Published: January 2005

AbstractThe normal rat tibialis anterior (TA) muscle was found to be innervated by approximately 154 spinal motor cells of which 95 are alpha motoneurons. Most of these axons ran in the L4 root and connected with glycolytic type 2B muscle fibers. The L5 root supplied 8.4% to 14.7% of the motor axons of TA muscle and innervated type 1 and 2A muscle fibers rich in oxidative enzymes. Two months after section of the peroneal nerve, there was marked fiber‐type grouping and compact rearrangement of the L4 and L5 motor units. After section of the L4 radicular nerve, the TA muscle remained atrophic with no evidence of fiber‐type grouping until 3 months when the L4 regenerating axons reached the muscle. Similar results were obtained after ligation of the divided ends of the L4 radicular nerve, which delayed but did not prevent reinnervation. These data suggest that, after partial denervation, muscle reinnervation by collateral sprouting is a slowly developing process.
Multiple forms of anti‐acetylcholine receptor antibody in myasthenia gravis
Authors: Mittag Tom , Massa Tobias , Kornfeld Peter , Papatestas Angelos , Bender Adam , Genkins Gabriel 
Published: January 2005

AbstractSera of patients with myasthenia gravis (MG) contain anti‐acetylcholine receptor (AChR) lgG antibodies (Ab) which have different antigenic specificities. Three Ab types were detected: (1) MG‐I, which forms immune complexes with AChR; (2) MG‐C, which decreases binding of AChR to concanavalin A; and MG‐B, which blocks α‐bungarotoxin binding to AChR. Sera from 152 MG patients were screened for the Ab types. Sixty‐one percent contained MG‐I, 26% contained MG‐C, 10% contained MG‐B, and 5% contained both MG‐C and MG‐B. The latter Ab types were associated with more severe forms of MG but showed no other clinical correlations. IgG antibodies of defined type were purified, and their interaction with unlabeled and toxin‐prelabeled AChR from denervated rat muscle was studied in detail. Receptors are homogeneous with respect to determinants recognized by MG‐I, but heterogeneous with respect to determinants recognized by MG‐C (3 subpopulations, 22%, 28%, and 50% of AChR) and by MG‐B (2 subpopulations, 30% and 70% of AChR). The stoichiometry of AChR interaction with the antibodies indicates that for each toxin‐binding site, the receptor is divalent as an antigen for MG‐I and MG‐C but is tetravalent for MG‐B. Denervated muscle AChR appears to be a mixture of at least 3 molecular forms of AChR, each of which has distinct immunological features as well as components common to all the receptor subpopulations.
Multiple genotypes, multiple phenotypes, and partial defects
Authors: Kark R. A. Pieter , Becker David M. 
Published: January 2005

AbstractIn recent years, the following ideas have been expressed: (a) that all cases of a discrete, inherited neuromuscular syndrome should prove to be due to a single biochemical defect, (b) that any single biochemical defect should give rise only to one syndrome, and (c) that an enzymatic defect cannot give rise to a disease unless there is virtual absence of activity, that is, less than 5% or 10% of the normal value. We review evidence from research in neuromuscular, neurological, and other genetic diseases of humans that suggests the contrary. There are now examples of single clinical syndromes related to each of several defects, of defects of one biochemical reaction related to two or more distinct clinical syndromes, and of partial defects associated with disease in a way that suggests a causal relationship.
Membrane elasticity of erythrocytes from normal and dystrophic mice
Authors: Missirlis Yannis F. , Vanderwel Marianne , Brain Michael C. 
Published: January 2005

AbstractThe membrane deformability of erythrocytes from normal and dystrophic mice was determined using a flow channel technique whereby erythrocytes attached to the floor of a parallel plate channel were deformed by fluid shear forces. A nonlinear stress‐strain experimental behavior was observed for both populations of erythrocytes which was best described with a polynominal expression: τS = aεx + [bεx3/(2εx + 1)]. A comprehensive statistical analysis of the data indicated that a large percentage of the variance of the data was due to the experimental design. Furthermore, the 2 populations of cells were different in terms of the strain‐stress relationship which best fitted the data, i.e., εx = ατs + βτs2 + γτs3. Up to a shear stress of 5.5 dyn/cm2, where 95% of the data points were found, the dystrophic erythrocytes were slightly but significantly more deformable than the normal erythrocytes.
Idiopathic torticollis: Sternocleidomastoid myopathy and accessory neuropathy
Authors: Sarnat Harvey B. , Morrissy Raymond T. 
Published: January 2005

AbstractBiopsies of the two heads of the sternocleidomastoid muscle were studied in 9 children with idiopathic torticollis, from 8 months to 17 years of age, who were undergoing surgical release of the sternal and clavicular attachments on the side of the contracture. Extensive fibrosis involved mainly the sternal head. Nonspecific myopathic changes, also mainly in the sternal head, included cytoarchitectural alterations of muscle fibers, necrosis, and focal inflammation. Histochemical type grouping and grouped atrophy were extensive in some cases and present in all except one, but the clavicular head was predominantly involved. Denervation and reinnervation are common chronic features in idiopathic torticollis, probably secondary to entrapment neuropathy: the accessory nerve reaches the clavicular head by passing through the sternal head. Separate arterial supplies predispose to ischemia in the sternal head, resulting in focal myopathy and fibrosis.
Properties of single motor units of the extensor digitorum brevis in elderly humans
Authors: Borg Jörgen 
Published: January 2005

AbstractThe axonal conduction velocity and volunatary discharge properties of single motor units of the extensor digitorum brevis were studied in elderly subjects. The results were compared with the findings of a previous study of younger subjects. The range of the axonal conduction velocities differed only slightly between the age groups, the elderly subjects having velocities of 25–52 m/sec and the younger subjects 30–54 m/sec. In both age groups, motor units firing tonically within the range of 10–30 Hz had axonal conduction velocities below 45 m/sec, and motor units firing mainly phasically within the range of 20–60 Hz had axonal conduction velocities above 40 m/sec. Motor units with an intermediate type of discharge pattern were more frequently seen in the elderly. In the elderly subjects, these motor units had axonal conduction velocities distributed within the whole range, while in the younger subjects, they had axonal conduction velocities in the middle of the range. An autopsy study showed an increased proportion of muscle fibers with intermediate characteristics of ATPase staining in the elderly subjects. It is suggested that the decreased differentiation of the muscle fiber histochemistry might be secondary to the decreased differentiation of the motoneuron firing properties.
A preparation for studying dystrophic avian muscle and neuromuscular junctions
Authors: Gunther J. S. , Letinsky M. S. 
Published: January 2005

AbstractThe extensor of the second digit of the chicken wing (EDII) is a small, fast‐twitch muscle susceptible to chicken muscular dystrophy and well‐suited for correlated studies of the morphology and physiology of identified nerve and muscle fibers. In cross section, the dystrophic EDII show morphological abnormalities common to other well‐studied dystrophic chicken muscles. However, in contrast to other dystrophic chicken muscles, living endplates can be viewed in the EDII, facilitating electrophysiological studies. A survey of electrophysiological properties of the EDII muscle in birds 5–16 weeks ex ovo revealed that compared to normal preparations, the dystrophic preparations had: (1) lower resting potentials, (2) lower miniature endplate potential frequency, (3) abortive nerve‐evoked action potentials recorded extrajunctionally, and (4) multiple muscle fiber action potentials to a single depolarizing current pulse.
Hereditary polymyopathy and cardiomyopathy in the syrian hamster. I. Progression of heart and skeletal muscle lesions in the UM‐X7.1 line
Authors: Jasmin G. , Proschek L. 
Published: January 2005

AbstractThe Syrian hamster polymyopathy is a hereditary disease, transmitted by an autosomal recessive gene, involving the heart and the entire musculature. The chronology of the pathologic events in the myocardium and skeletal muscle has been investigated in UM‐X7.1 myopathic hamsters aged 0–250 days. A phasic pattern in the progression of the disease process was evident. Microscopic necrotic changes in the heart were visible prior to or at 50 days of age with increasing severity until 100 days of age and subsidence thereafter. More than 50% of the animals died before 250 days of age with signs of cardiac failure. The intensity and extent of myocardial calcific changes together with scar formation were determinant factors in curtailing the survival of animals. Changes in serum creatine kinase (CK) activity followed a phasic pattern similar to the progression of the myopathic disease. Because of the disparity of disease manifestations between the different myopathic hamster lines, it is essential to consider the time course of the heart and skeletal muscle microscopic changes when evaluating the severity of the hamster polymyopathy.
Hereditary polymyopathy and cardiomyopathy in the syrian hamster. II. Development of heart necrotic changes in relation to defective mitochondrial function
Authors: Proschek L. , Jasmin G. 
Published: January 2005

AbstractThe mitochondrial oxidative phosphorylation, calcium and magnesium contents, and swelling‐contraction activity were investigated in relation to the progression of the hereditary hamster cardiomyopathy. The assessment was made in animals between 22 and 232 days of age, which were divided into 7 groups according to stage of disease. In 24‐day‐old hamsters prior to development of heart necrotic changes, the membrane permeability of isolated mitochondria was altered. In 50‐day‐old animals, at a stage of disease when myocardical cells undergo degeneration, a defect of oxidative phosphorylation resulting from an increase in mitochondrial calcium was demonstrated. With culmination of the heart necrotic changes, at close to 100 days of age, mitochondrial dysfunction and calcium overload were maximal. There was a transient improvement during the healing stage, but the situation deteriorated with the occurrence of circulatory failure. Since the mitochondrial respiratory pattern and calcium overload parallel the cardiac degeneration, it is inferred that the cell energy depletion is a functional consequence of an abnormal calcium influx.
Ganglioside treatment of neuropathy in diabetic mice
Authors: Norido Franco , Canella Roberto , Gorio Alfredo 
Published: January 2005

AbstractDiabetic neuropathy in 180‐day‐old C57BL/Ks inbred mice is characterized by a marked reduction of nerve conduction velocity (NCV) and by axonal atrophy, as suggested by the decreased number of large diameter myelinated fibers. No demyelination or remyelination was observed. Ganglioside treatment from 150 to 180 days of age significantly improved the NCV and returned the fiber size distribution to control values.
Sarcolemmal desmosterol accumulation and membrane physical properties in 20,25‐diazacholesterol myotonia
Authors: Chalikian David M. , Barchi Robert L. 
Published: January 2005

AbstractIn rats treated biweekly with 20,25‐diazacholesterol (200 mg/kg orally), the desmosterol level in skeletal muscle sarcolemma increased progressively to about 80% of membrane sterol while total sterol levels remained constant. Following a single oral dose of 20,25‐D, the kinetics of desmosterol accumulation and subsequent loss in sarcolemma were more rapid than in whole muscle homogenates. The anisotropy of diphenylhexatriene fluorescence and the calculated microviscosity of the probe's microenvironment decreased significantly with increasing desmosterol levels in a temperature‐dependent manner, although fluorescent lifetimes were not altered. Fluorescent probes which localize in more superficial regions of the membrane detected no change. Studies with erythrocyte ghost membranes yielded results comparable to sarcolemma. Replacement of membrane cholesterol with desmosterol reduced the local microviscosity of the membrane hydrophobic region associated with phospholipid acyl chains and sterol side chains, but had little apparent effect on more superficial, polar regions. These observations can be correlated with the membrane location of the unsaturated side chain in desmosterol.