bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence against a generalized membrane defect in dystrophic mice platelets
Authors: Mizobe Fumio , Livett Bruce G. 
Published: January 2005

AbstractThe response of the membrane‐bound enzyme AChE to changes in temperatures was investigated to test the applicability of the “generalized membrane defect” hypothesis proposed for human myotonic and Duchenne muscular dystrophies to the two forms of muscular dystrophy expressed in mice. For intact platelets from homozygous normal and dystrophic mice of both strains, a break (Tc) occurred in the Arrhenius plot of AChE activity at approximately 22 C. Solubilization of membrane‐bound AChE by Triton X‐100 produced a nonlinear Arrhenius plot over the temperature range (7.7 C to 37 C) in normal and dystrophic mice of both strains. However, in the presence of phospholipase A2 + C and Triton X‐100, a linear Arrhenius plot was produced indicating that the membrane‐bound enzyme is normally modulated by a bulk lipid domain as well as by a tightly bound (immobilized) phospholipid domain. The temperature response of platelet AChE from normal and dystrophic mice of both strains was not significantly different. These results showing normal temperature kinetics of AChE do not lend support to the theory of a membrane defect in the platelets of dystrophic mice.
Morphometric analyses of human muscle fiber types
Authors: Sjöström Michael , Ängquist Karl‐Axel , Bylund Ann‐Christin , Fridén Jan , Gustavsson Lennart , Scherstén Tore 
Published: January 2005

AbstractFibers from the m. vastus lateralis of 10 middle‐aged men were classified at ultrastrctural level according to the appearance of the sarcomeric M‐band. The Z‐band widths had a two‐peak distribution. One peak was due to type 1 fibers (mean 125 ± 11 nm), the other to type 2 fibers. This latter could be separated into type 2A (101 ± 9 nm) and type 2B (86 ± 8 nm). About 83% of the fibers would have been correctly classified on the basis of the Z‐band width alone. Mitochondrial volumes differed (type 15.6 ± 0.8, 2A 4.0 ± 0.8, and 2B 2.8 ± 0.8%). However, only one third (37%) of the fibers would have been correctly classified if sorted according to this parameter. Mitochondrial volumes in the different fibers were correlated to mitochondrial enzymes, while fiber sizes and numbers were correlated to cytoplasmic variables. The correlations appeared mainly after a training program, suggesting that the relationships between structural and functional parameters are more obvious after adaptation to higher functional demands.
Training‐induced increase in myofibrillar ATPase intermediate fibers in human skeletal muscle
Authors: Schantz Peter , Billeter Rudolf , Henriksson Jan , Jansson Eva 
Published: January 2005

AbstractThe response of human muscles triceps brachii and vastus lateralis to training, consisting of 18.5 miles a day of skiing with a backpack, 6 days a week for 8 weeks, has been investigated by means of histochemical fiber typing (myofibrillar ATPase) as well as immunohistochemical discrimination of slow and fast myosin (n = 6). A detraining period of 33 weeks was also studied. The percentage of type 2 fibers decreased by 6% in the triceps brachii during training, whereas the intermediate fiber type increased by 4%. No change was found in the distribution of fiber types in the vastus lateralis during training or in both muscles during detraining. The ATPase intermediate fibers also stained intermediately in the immunohistochemical stainings for slow and fast myosin. These results show that transformation of a fraction of the type 2 fibers into the intermediate type may occur as a response to endurace training.
Muscle granulomas following intramuscular injection
Authors: Mrak Robert E. 
Published: January 2005

AbstractAn 8‐month‐old child underwent a muscle biopsy because of hypotonia. The biopsy showed centronuclear myopathy and, in addition, an unusual granulomatous inflammatory infiltrate. The child died of respiratory complications and a complete autopsy failed to reveal further evidence of granulomatous disease. The lesion was reproduced in experimental animals by intramuscular injection of diphtheria and tetanus toxoids and pertussis vaccine. Granular material present in histiocytes in these lesions was shown histochemically to be an aluminum salt.
Branched skeletal muscle fibers not associated with dysfunction
Authors: Brown Lucy M. , Lopez Jose R. , Olsen Jean A. , Rüdel Reinhardt , Simmons Robert M. , Taylor Stuart R. , Wanek Laurel A. 
Published: January 2005

AbstractWe report the occurrence of large clefts and branches in some amphibian vertebrate skeletal muscle fibers. Such fibers can be isolated intact from various skeletal muscles of fully mature animals and apparently are normal in other respects. Electron micrographs showed no signs of degeneration in most fibers. Electrical and mechanical studies revealed that all branches were excitable and able to contract. Branches evidently can arise in the absence of abnormal influences such as experimentally induced overload. The apparent cause may be either fusion or splitting of fibers.
Myofiber differentiation in normal and hypotrophied canine pectineal muscles
Authors: Cardinet George H. , Leong Charlotte L. , Means Penelope S. 
Published: January 2005

AbstractThe myofiber type composition of pectineal muscles was determined in 21 mixed‐breed pups at 1 through 79 days of age and in 22 8‐week‐old‐pups (4 mixed‐breed, 5 greyhound and 5 German shepherd pups with normal muscles, and 8 German shepherd pups with myofiber hypotrophy). Sections were stained for the histochemical demonstration of myofibrillar adenosine triphosphatase by incubation in media at pH 9.8 without preincubation and following preincubation in acid media at pH 4.5 and at pH 4.3. At day 1 most myofibers were type 2C (alkaline and acid stable) while the remainder were type 1A myofibers (alkaline labile; acid stable) which had differentiated prenatally. Subsequently, the number of type 2C myofibers decreased while the number of type 1A and type 2A myofibers (alkaline stable; acid labile at pH 4.5 and pH 4.3) increased. Type 1B myofibers (partially alkaline stable; acid stable) were first observed at day 12 and were variably present through day 79. Type 1B myofibers appeared to be a transition form of type 2C to type 1A differentiation. Type 2B myofibers (alkaline stable; acid stable at pH 4.5; acid labile at pH 4.3) were not observed. Hypotrophied muscles contained more type 2C and fewer type 2A myofibers and all myofiber types were smaller than normal. These results suggest that the pathogenesis of this disorder involves both myofiber growth and differentiation, particularly differentiation of type 2A myofibers.
Muscle function in rheumatic disease patients treated with corticosteroids
Authors: Rothstein Jules M. , Delitto Anthony , Sinacore David R. , Rose Stephen J. 
Published: January 2005

AbstractClinical and experimental data indicate that long‐term corticosteroid use leads to atrophy of the type 2 muscle fibers. The purpose of this study was to characterize and quantify the nature of muscle function in rheumatic disease patients who have been on long‐term corticosteroid therapy. Quadriceps function (i.e., peak torque and power) in 19 patients (11 with rheumatoid arthritis, five with systemic lupus erythematosis, and 3 other) and 11 age‐ and activity‐matched normal controls was measured with an isokinetic dynamometer (Cybex II), during four constant velocity movements. Power was significantly lower for the patients at all speeds. At the higher speeds the patients' deficit in power production increased as indicated by a difference in the slopes of power‐velocity regression lines. Measures of peak torque could not be consistently used to differentiate the groups. Patients with rheumatic diseases receiving corticosteroids have a decreased ability to generate muscle power. The method described allows for quantification of these deficits in a clinical setting.
Morphometric analysis of aging skeletal muscle following endurance training
Authors: Silbermann Michael , Finkelbrand Sara , Weiss Anna , Gershon David , Reznick Abraham 
Published: January 2005

AbstractAging of skeletal muscle in the hindleg of the mouse is accompanied by a progressive increase in the amount of the interstitial tissue and especially that of lipid cells and fibroblasts. Quantitative analysis indicates that there was a nonsignificant increase in the total number of muscle fibers per unit area, perhaps due to a splitting process. The proportion of high oxidative fibers was decreased to a nonsignificant degree, and the remaining high oxidative fibers underwent a significant compensatory hypertrophy. Concomitantly, the number of low oxidative fibers increased significantly. This study revealed that endurance training in young animals induced morphometric changes very similar to those noticed in intact aging animals (i.e., splitting phenomenon, hypertrophy of high oxidative fibers, and an increased proportion of low oxidative fibers). It also became apparent that the skeletal muscle of old animals lacks the capacity to respond to enforced training, except for a further increase in the proportion of low oxidative fibers. It appears that aging muscle is unable to adapt to changing environmental circumstances.
Respiratory improvement by muscle training in adult‐onset acid maltase deficiency
Authors: Martin Richard J. , Sufit Robert L. , Ringel Steven P. , Hudgel David W. , Hill Patricia L. 
Published: January 2005

AbstractA patient with progressive involvement of respiratory function from adult‐onset acid maltase deficiency is reported. The decrement in objective and subjective waking and sleeping respiratory variables was significantly reversed by inspiratory muscle training. This training was accomplished simply by breathing against inspiratory resistors for 15 minutes twice a day. Inspiratory muscle training may prove valuable in other patients with progressive neuromuscular disorders that involve respiratory muscle function.
Intracellular elemental content of cardiac and skeletal muscle of normal and dystrophic hamsters
Authors: Smith Nancy K. R. , Morris Sidra S. , Richter Michael R. , Cameron Ivan L. 
Published: January 2005

AbstractTo test the hypothesis that the genetic lesion causing muscular dystrophy might be reflected in an abnormal intracellular elemental content, the elemental content of individual cardiac and skeletal muscle fibers in 50‐day‐old male control and cardiomyopathic BIO 53.58 hamsters was determined. The technique of electron probe x‐ray microanalysis of freeze‐dried tissue was employed. No electrolyte content differences were found between control and diseased animals for nuclei, myofibrillar cytoplasm, or mitochondrially‐enriched cytoplasm of cardiac myocytes. Sulfur was elevated in dystrophic cardiac myocytes and was the only element significantly different in heart tissue of control and cardiomyopathic animals. Sulfur was also elevated in dystrophic soleus muscle fibers. The pattern of electrolyte content of these cells reflected a mixture of normal cells and damaged cells with altered electrolyte content. In this hamster model, alteration of electrolyte content of myocytes appears to be a result of the disease process and not an inherent characteristic of muscular dystrohy. The elevated sulfur in dystrophic hamster myocytes reflects a biochemical lesion which deserves further study.
Hypertrophic form of peroneal muscular atrophy (PMA): Unusual nerve conduction results
Authors: Streib Erich W. , Sun Sallie F. , Kimberling William , Smith Stephen A. 
Published: January 2005

AbstractA family with a hypertrophic form of peroneal muscular atrophy (PMA) was studied with typical clinical and electrophysiological abnormalities in the propositus and her child. The propositus' fater was asymptomatic and slowing of nerve conduction velocities was limited to the peroneal nerves. Actual parentage was confirmed by 22 different serologic and electrophoretic marker systems.
Membrane protein phosphorylation in the intact erythrocytes of genetically dystrophic hamsters
Authors: Johnson Robert M. 
Published: January 2005

AbstractMembrane protein phosphorylation has been measured in both normal and dystrophic (BIO 53.58) hamsters. After radiolabeling intact erythrocytes with exogenous 32Pi, band 3 polypeptides from dystrophic hamsters had increased incorporation of 32P, compared to age‐matched controls. This was verified by membrane protein fractionation. The use of intact cell phosphorylation avoids many of the sources of experimental variability noted in experiments with isolated membranes. This work, using an animal model for the disease, supports the hypothesis of a generalized membrane defect in the muscular dystrophies.
Heterogeneity of type 1 skeletal muscle fibers revealed by monoclonal antibody to slow myosin
Authors: Shafiq Saiyid A. , Shimizu Teruo , Fischman Donald A. 
Published: January 2005

AbstractMonoclonal antibodies (McAbs) were generated against slow myosin from the chicken anterior latissimus dorsi (ALD) muscle and their reactivity was checked against fast (pectoralis), slow (ALD), cardiac (ventricular), and smooth (gizzard) myosins by radioimmunoassay (RIA), immunoautoradiography (immunoblots), and indirect immunofluorescence techniques. In RIAs, the McAb (ALD‐58) described in this article reacted specifically with slow myosin, with only a weak cross‐reactivity to cardiac myosin. In immunoblots against whole muscle homogenates and purified myosins, it bound selectively to the 200 Kd myosin heavy chain band. The ALD‐58 antibody stained the fibers of the ALD muscle uniformly but gave three grades of reactions (strong, weak, and negative), with histochemically identified type 1 fibers of sartorius and gastrocnemius muscles demonstrating the immunological heterogeneity of myosins in type 1 skeletal muscle fibers.
31P‐NMR studies of normal and dystrophic chicken muscle
Authors: Pettegrew Jay , Minshew Nancy , Feit Howard 
Published: January 2005

AbstractPhosphorus‐31 nuclear magnetic resonance (31P‐NMR) analysis was performed on normal (line 412) and dystrophic (line 413) superficial pectoralis muscles excised from chickens between 15 and 116 days after hatching. An apparent alteration in dystrophic muscle energy metabolism was abolished by pretreatment with curare and was attributed to muscle hyperexcitability. Time‐dependent 31P‐NMR studies demonstrated no apparent difference in the overall tissue adenosine triphosphatase (ATPase) activity of dystrophic as compared to normal muscle. After 55 days of age, a resonance signal attributed to serine ethanolamine phosphodiester (SEPDE) was observed only in dystrophic muscle. Adding the paramagnetic cation Mn2+ to the buffer surrounding the muscle resulted in an approximate 80% decrement in the dystrophic SEPDE signal without apparent alteration of the other phosphatic signals in either the normal or dystrophic muscle. This would argue against any generalized membrane defect in dystrophic chicken muscle and suggest that SEPDE is in a compartment accessible to Mn2+.
Failure of neuromuscular transmission and contractility during muscle fatigue
Authors: Pagala Murali K. D. , Namba Tatsuji , Grob David 
Published: January 2005

AbstractIn previous studies of muscle fatigue, tension was monitored from whole muscle, while action potentials were recorded from a few muscle fibers. To compare more accurately changes in these responses, an in vitro fluid electrode technique was employed to record the action potential of whole muscle simultaneously with tension during fatigue induced by nerve stimulation in the rat extensor digitorum longus (EDL), soleus, and diaphragm muscles. In each muscle, tension declined from the start of stimulation, while action potential amplitude initially increased slightly and then declined most rapidly in EDL, more slowly in diaphragm, and most slowly in soleus. Direct stimulation of the fatigued muscle produced the greatest increase in tension in EDL, next in diaphragm, and least in soleus. These results indicate that while failure of excitation‐contraction coupling or of the contractile mechanism is the initial cause of fatigue in all the muscles studied, and remains the predominant cause throughout in the soleus muscle, failure of neuromuscular transmission plays an important role in fatigue after the first 15 seconds in EDL, and to a lesser extent, after the first 90 seconds in diaphragm.
Changes in muscle contractile properties and neural control during human muscular fatigue
Authors: Bigland‐Ritchie B. , Woods J. J. 
Published: January 2005

AbstractThe factors limiting force production and exercise endurance time have been briefly described, together with some of the changes occurring at various sites within the muscle and central nervous system. Evidence is presented that, in fatigue of sustained maximal voluntary contractions (MVC) executed by well‐motivated subjects, the reduction in force generating capacity need not be due to a decline in central nervous system (CNS) motor drive or to failing neuromuscular transmission, but can be attributed solely to contractile failure of the muscles involved. However, despite this conclusion, both the integrated electromyogram (EMG) and the mean firing rate of individual motor units do decline progressively during sustained MVC. This, however, does not necessarily result in loss of force since the parallel slowing of muscle contractile speed reduces tetanic fusion frequency. It is suggested that the range of motoneuron firing rates elicited by voluntary effort is regulated and limited for each muscle to the minimum required for maximum force generation, thus preventing neuromuscular transmission failure and optimizing motor control. Such a CNS regulating mechanism would probably require some reflex feedback from the muscle.
Immunohistochemical study of myoglobin in neuromuscular diseases
Authors: Kagawa Noriko , Hizawa Kazuo 
Published: January 2005

AbstractThe localization of myoglobin (Mb) in skeletal muscle in various neuromuscular diseases was studied by an immunoperoxidase technique. The immunoreactivity of Mb was shown to be well preserved in muscle fibers that showed denervation atrophy or vacuolar degeneration, as well as in muscle fibers with apparently normal structure. Marked decrease or loss of Mb immunoreactivity was observed in muscle fibers with hyaline degeneration or floccular necrosis, where there was irreversible disruption of the muscle fibers. On the other hand, regenerated fibers showed variable immunostaining for Mb. Most regenerated fibers showed little or no immunostaining but some showed staining as strong as apparently normal fibers. These findings in various neuromuscular diseases suggested that the elevation of serum Mb in patients with these diseases was ascribed to its release from severely injured, necrotic muscle fibers. The immunohistochemistry for Mb was shown to be useful to evaluate plasma membrane injury and characterize muscle degeneration.
Pseudo‐anterior interosseous nerve syndrome
Authors: Wertsch Jacqueline J. , Sanger James R. , Matloub Hani S. 
Published: January 2005

AbstractThe anterior interosseous nerve syndrome (AINS) is well known. A case is presented that had electromyographic findings limited to the distri‐bution of the anterior interosseous nerve. A small area of sensory loss and slight asymmetry of amplitudes noted on median nerve conduction studies were inconsistent with an AIN syndrome. An antecubital level partial median nerve compromise primarily involving the bundles that form the anterior interosseous nerve was surgically noted. This case illustrates that localization of a peripheral nerve lesion must include consideration of the internal topography of peripheral nerves.
Activity of 2′3′‐cyclic‐nucleotide 3′‐phosphodiesterase and content of PO protein in the peripheral nervous system of the dystrophic mouse and chicken
Authors: Lewis Lorraine N. , Mezel Catherine 
Published: January 2005

AbstractTo investigate whether various myelin markers could detect pathological changes in myelination, the activity of 2′‐3′‐cyclic nucleotide 3′‐phosphodiesterase (CNP) and the level of PO protein were compared in the peripheral nervous system (PNS) of the dystrophic mouse and chicken and their phenotypically normal siblings. The same comparison was made for subcellular fractions of these nerves. The level of PO protein and the activity of CNP were normal in the spinal roots of sciatic nerves of the 129B6F1/Jdy/dy strain of dystrophic mouse. These parameters were slightly but significantly lower in the spinal roots of the 129REJ/dy/dy strain of dystrophic mouse. These results suggest that the 129B6F1/Jdy/dy mutant and the 129REJ/dy/dy mutant mouse might not have the same type of biochemical abnormality in their PNS. The specific activity of CNP and the proportion of PO protein increased significantly in the various regions of the PNS of 1‐day‐old chicks when compared to that of the 18‐day‐old embryos. Subcellular fractionation of peripheral nerves indicated that these components were enriched in the crude myelin fraction. These results support the conclusion that PO protein and CNP are suitable markers of myelinogenesis in the PNS of the chick. These parameters were normal in the line 413 dystrophic chicken. These results do not support the conclusion of a systemic membrane defect in the PNS of the dystrophic mouse and chicken.
Protein degradation in cultured skeletal muscle from duchenne muscular dystrophy patients
Authors: Neville Hans E. , Harrold Sharon 
Published: January 2005

AbstractThe loss of contractile protein in Duchenne muscular dystrophy could result from low rates of synthesis, abnormally high rates of protein degradation, or a combination of both. We measured overall protein degradation rates in cultured human muscle cells obtained at biopsy from patients with Duchenne dystrophy or various muscle diseases and normal subjects. Measurements were performed on confluent cultures exhibiting no growth and containing a mixed cell population of myoblasts, fibroblasts, and multinucleated myotubes. Using a new doubleisotope labeling protocol, we found protein degradation rates in all three groups to be similar (KD = 0.0171–0.0176 hr−1), suggesting no detectable abnormality of overall protein degradation in cells derived from Duchenne dystrophy patients.
Familial neuromuscular disease with tubular aggregates
Authors: Pierobon‐Bormioli Sandra , Armani Mario , Ringel Steven P. , Angelini Corrado , Vergani Ludovica , Betto Romeo , Salviati Giovanni 
Published: January 2005

AbstractWe have studied four members of a family in which five individuals of both sexes in three generations have mild weakness and muscle aching. Serum creatine kinase (CK) and/or aldolase were mildly to moderately elevated. Tubular aggregates were present in all patients in all fiber types. Type 1 fiber predominance and type 2 hypotrophy or atrophy was noted in three biopsies. Fiber splitting was prominent in two cases. Electron microscopic studies confirm that the tubular aggregates originate from muscle sarcoplasmic reticulum (SR). The presence of T tubules making contacts with some tubules inside the collection of tubular aggregates is suggestive of their derivation from terminal cisternae.
Initiation of differentiation into skeletal muscle fiber types
Authors: Dhoot Gurtej K. 
Published: January 2005

AbstractA monoclonal antibody directed against a slow isoform of a 100‐K myofibrillar protein has been used to study the differentiation of muscle fibers in the fast and slow muscles of the rat. Immunohistochemical studies have shown that initiation of differentiation into fast and slow muscle fibers occurs very early during development. The distribution pattern of cell types in different muscles is unique and is also determined very early during fetal muscle development. It is concluded that motor innervation is probably not essential to initiate differentiation into distinct muscle fiber types.