bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructure of the developing myotendinous junction of genetic dystrophic chickens
Authors: Sweeny Philip Randolph 
Published: January 2005

AbstractThis paper presents an ultrastructural study of the changes occurring within the tendon and at the insertion of the developing gastrocnemius of White Leghorn chickens and the dystrophic lines 413 and 423 from Davis, CA. The study revealed that the Davis lines contained abnormalities in these areas as early as 13 d in ovo with progressive deterioration to 19 d in ovo. The fibroblasts, collagen, and myofibers showed significant alterations as early as 13 in ovo. Fibroblasts contained abnormal mitochondria and altered Golgi bodies. At day 19, many were ruptured. The average diameter of collagen fibrils was smaller in the dystrophic chickens and myofibers showed a variety of alterations, some of which were severe. The details of these alterations are described and their possible relationship with the etiology of genetic muscular dystrophy is discussed.
Acute abdominal rhabdomyolysis after body building exercise: Is there a “rectus abdominus syndrome?”
Authors: Schmitt H. P. , Bersch W. , Feustel H. P. 
Published: January 2005

AbstractReport of a 19‐year‐old man who was admitted to the hospital after vigorous exercise with signs of the “acute abdomen” syndrome. Since intestinal reasons for the complaints were excluded, a myocardial infarction was considered. However, the excessively increased serum CK levels indicated a disorder of the voluntary muscles. A biopsy taken from the rectus abdominis revealed typical features of acture rhabdomyolysis, which was obviously restricted to the rectus abdominis. Together with a somewhat later observed autopsy case of a young male with acute abdominal rhabdomyolysis, also restricted to the rectus abdominis, this case gives rise to discuss, whether there exists a “rectus abdominis syndrome” analogous to the anterior tibial syndrome.
Acetylcholine receptor turnover in clonal muscle cells: Role of plasmin and effects of protease inhibitors
Authors: Romstedt Karl , Beach Robert L. , Festoff Barry W. 
Published: January 2005

AbstractCharacteristics of acetylcholine receptors were evaluated in G8‐1, a continuous skeletal muscle line. Peak binding of 125I‐α‐bungarotoxin was in 10‐day‐old contractile myotubes at 4‐8 nm. Turnover was studied using two different methods; both indicated half‐times as little as half as long as previously reported for primary cultures. The effects of a variety of protease inhibitors on receptor turnover were assessed to determine if G8‐1 receptors were less stable or turned over faster because of increased neutral protease activity. Leupeptin, antipain, and chloroquine markedly slowed receptor degradation. Inhibitors of plasmin or plasminogen activator had definite but less dramatic effects on receptor turnover. Results from studies in which plasmin was increased in the tissue culture media indicated that a small but definite acceleration of receptor turnover occurred. In clonal G8‐1 cells, total number of acetylcholine receptors is controlled by negative feedback and although the major pathway for receptor degradation is lysosomal, plasmin may play a role in initiating receptor internalization.
Interaction of monoclonal antibodies to torpedo acetylcholine receptor with the receptor of skeletal muscle
Authors: Souroujon Miry C. , Mochly‐Rosen Daria , Gordon Adrienne S. , Fuchs Sara 
Published: January 2005

AbstractSeveral monoclonal antibodies (mcAbs) elicited against the nicotinic acetylcholine receptor (AChR) from Torpedo react also with skeletal muscle AChR. Such mcAbs were used to define antigenic determinants on muscle AChR and to elucidate their effect on muscle AChR functions. Primary chick muscle cultures were used as a model for skeletal muscle. Of the four mcAbs studies only mcAb 5.5, which is directed against the cholinergic site in Torpedo AChR, blocks the binding of α‐bungarotoxin (α‐β) to AChR in chick muscle cultures and inhibits carbamylcholine‐induced sodium transport in these cells. The interaction of mcAb 5.5 with the cholinergic site on muscle AChR demonstrates the conservation of this site. Two mcAbs, 5.5 and 5.34, each of a different antigenic specificity but both directed against conformation‐dependent antigenic determinants, accelerate the degradation of AChR in muscle cultures. From the reactivity of the various mcAbs with Triton‐solubilized and membranous AChR it appears that there are some antigenic differences between the detergent solubilized and membranous forms of the receptor.
Effect of denervation on glycogen metabolism in fast and slow muscle of rat
Authors: Moruzzi Emma Villa , Bergamini Ettore 
Published: January 2005

AbstractThe postdenervation changes in glycogen metabolism were explored in fast (extensor digitorum longus, EDL), and slow (soleus, S) muscle of rat. During the first 12–14 hours after denervation, glycogen accumulates to a similar content in the two muscles, an effect reproduced by paralysis. Increase in the molecular weight of glycogen and decrease in the turnover rate of similar degree occur. During the ensuring 12–24 hours the glycogen concentration decreases in EDL (but not in S). This decrease is influenced by factors such as muscle type, longer or shorter nerve stump, age, and previous training of the animal. In both EDL and S, the rate of glucose incorporation into glycogen and the glycogen synthase [l/(l + D)] activity were depressed by denervation. The cAMP concentration increased 36 hours after denervation. This may have consequences on the muscle sensitivity to hormones. In fact, at this time, insulin did not increase glycogen synthase l activity or the glycogen content (with the exception of glycogen in S) and the effects of epinephrine on glycogen metabolism became more significant.
Membrane crystals of Ca2+‐ATPase in sarcoplasmic reticulum of normal and dystrophic muscle
Authors: Dux Laszlo , Martonosi Anthony N. 
Published: January 2005

AbstractTwo‐dimensional crystalline arrays of the Ca2+ transport ATPase develop after treatment of sarcoplasmic reticulum vesicles with Na3VO4. The dimensions of the crystal lattice are similar in sarcoplasmic reticulum membranes isolated from normal and genetically dystrophic human, mouse, and chicken muscles. These observations indicate similar requirements for ATPase‐ATPase interactions in sarcoplasmic reticulum of normal and dystrophic muscles and lessen the likelihood of a molecular defect of the Ca2+ pump in the various forms of genetic muscular dystrophies.
Susceptibility of mouse skeletal muscles to exercise injuries
Authors: Salminen Antero , Vihko Veikko 
Published: January 2005

AbstractThe susceptibility to exercise‐induced myopathy was studied by histological and biochemical methods in various skeletal muscles of mice 3–4 days after a single bout of prolonged running. The degree of exercise injuries varied greatly in different muscles. Soleus and the red deep parts of quadriceps femoris were the most severely affected muscles. Extensive or scattered necrosis of muscle fibers was associated with focal inflammation and a five‐ to nine‐fold increase in the activity of β‐glucuronidase in these muscles. Slight necrotic changes and a two‐ to three‐fold increase in the activity of β‐glucuronidase were observed in tibialis anterior, plantaris, and the red deep parts of gastrocnemius. A statistically significant increase in β‐glucuronidase activity was also observed in the white distal part of quadriceps femoris, biceps femoris, gracilis, extensor digitorum longus, and peroneal muscles but necrotic lesions were infrequent in these muscles. The degree of exercise injuries is probably affected by the different recruitment of muscles during running and by the anatomical location of muscles in separate compartments, which could expose them to differnt levels of ischemic compression by postexercise edema.
Divalent cations and temperature dependent block of impulse propagation at the frog neuromuscular junction
Authors: Eusebi Fabrizio , Miledi Ricardo 
Published: January 2005

AbstractEnd‐plate potentials were recorded from superficial muscle fibers of the frog sartorius nerve‐muscle preparation. Exposure of the preparation to a medium containing a high divalent cation concentration, produced a temperature dependent failure of neuromuscular transmission. Failure of transmission developed in an “all‐or‐none” mode and was reversed by decreasing the bath temperature or divalent cation concentration. This blockage of the neurotransmission is attributed to a presynaptic block of impulse propagation.
Cylindrical spirals in skeletal muscle: A further observation with clinical, morphological, and biochemical analysis
Authors: Gibbels Ellen , Henke Ursula , Schädlich Hans‐J. , Haupt Walter F. , Fiehn Walter 
Published: January 2005

AbstractCylindrical spirals are abnormal uniform membranous inclusions in skeletal muscle, usually confined to type 2 fibers. Hitherto, only five cases have been published with various clinical syndromes. Here, a case is presented for the first time with detailed electrophysiological, histometrical, and biochemical analysis: a 60‐year‐old man with slowly progressing polyneuropathy confirmed by electrophysiological findings, and a history of diabetes, alcoholism, nicotine abuse, and weight reduction. In various muscle biopsies, large aggregates of cylindrical spirals were found almost exclusively in type 2B fibers. Obviously, the aggregates were derived from abnormal perinuclear and, therefore, mainly subsarcolemmal tubulovesicular structures. Morphometrical, histochemical, and biochemical analysis of muscle revealed no further information about the nature of these inclusions. They were not present in skin biopsy containing subcutaneous nerves.
The effect of spinal cord transection on motor units in cat medial gastrocnemius muscles
Authors: Mayer R. F. , Burke R. E. , Toop J. , Walmsley B. , Hodgson J. A. 
Published: January 2005

AbstractWe studied the properties of whole medial gastrocnemius (MG) and soleus muscles, and of 74 individual MG motor units in three cats with long‐term complete low thoracic spinal transection (TS). All animals remained paraplegic and there was considerable atrophy of MG and soleus muscles. Motor units in the MG pool were readily classified into the same groups, types FF, F(int), FR, and S, found in normal MG, but tetanic force outputs and mean fiber areas for the corresponding muscle fiber types were decreased in all unit types as were isometric twitch contraction times. The proportion of type F(int) motor units was greater (19.0%) than expected from normal samples (5.8%) and this was also true of the corresponding type 2AB muscle fibers (6.9% in TS vs 3.3% in controls). In addition, FR and S units were less numerous (17.5% each) than in control muscles (23.0% and 25.2%, respectively), and histochemical examination revealed a similar decrease in the percentage of type 2A (11.6%) and 1 (16.4%) fibers compared with controls (20.0% and 30.5%, respectively). The changes found in chronic paraplegic atrophy were different in some details from those found after chronic simple limb immobilization.
The effect of denervation on mammalian sarcolemmal proteins and glycoproteins
Authors: Leung Wing Nang , Jeffrey Peter L. , Rostas John A. P. 
Published: January 2005

AbstractThe effects of surgical denervation on proteins and glycoproteins of sarcolemmal membranes have been investigated using sarcolemmal fractions prepared from mixed rat muscles. Denervation did not cause any gross change in the protein composition but some consistent quantitative changes were detected. Denervation caused a significant increase in the binding of 125l‐labeled concanavalin A (ConA), Ricinus communis agglutinin (RCA120), and wheat germ agglutinin (WGA) to intact membranes. This increased binding appears to be brought about by two mechanisms: the synthesis of more binding‐sites with the same apparent KD and the unmasking of previously cryptic binding sites. The activity of sialyl‐, galactosyl‐, and N‐acetylglucosaminyltransferases in the sarcolemmal fractions increased, whereas fucosyl‐glycoprotein‐transferase activity decreased following denervation. Kinetic analysis of the sialyl‐ and galactosyltransferase activities showed that the change was due to an increase in Vmax with no change in Km. These results are consistent with an increase in the turnover of sarcolemmal glycoproteins following denervation.
Accessory nerve stimulation in the assessment of myasthenia gravis
Authors: Schumm Fritz , Stöhr Manfred 
Published: January 2005

AbstractRepetitive nerve stimulation (5/second) was done at the median nerve at the wrist and at the accessory nerve just behind the sternocleidomastoid muscle before and 20 seconds to 5 minutes after tetanic nerve stimulation (1 minute). Since the degree of the neuromuscular block depends on the body temperature these investigations were done successively at skin temperatures of 32°C and 36°C. A comparison of the results obtained revealed the highest rate of pathologic decrement with posttetanic accessory nerve stimulation (32°C = 77%, 36°C = 87%), whereas with posttetanic median nerve stimulation pathological results were obtained in a significantly lower proportion (32°C = 50%, 36°C = 60%). The advantages of the stimulation of the accessory nerve for the detection of partial neuromuscular block are: 1. The superficially located accessory nerve allows for supramaximal stimulation with rather low stimulus intensities (6–20 mA). 2. Since the accessory nerve is mainly a motor nerve, the stimulation is less painful than the stimulation of a mixed nerve. 3. Stimulation of a proximal nerve is more sensitive for detecting a defect in neuromuscular transmission than stimulation of a distal nerve. 4. There is no risk of a pneumothorax and of a traumatic nerve lesion as there is with stimulation of the brachial plexus by needle electrodes.
Early effects in vitro of the muscular dysgenesis mutation on nervous tissue in the mouse
Authors: Wieczorek David F. 
Published: January 2005

AbstractMuscular dysgenesis (mdg), a disease expressed in embryonic mice, severely affects the formation and differentiation of skeletal musculature. The focus of this investigation was an analysis of dysgenic nervous tissue with special attention centered on interactions between muscle and nerve cells in vitro. Results indicate that mdg/mdg spinal cord cells can form functional neuromuscular junctions in nervehyphen;muscle cocultures and induce contractions in dysgenic muscle. However, dysgenic spinal cord cells induce fewer myotubes to contract and result in a delayed induction of dysgenic myotube contractile activity. Furthermore, mdg/mdg nervous tissue, or its conditioned medium, is associated with a higher incidence of morphologically abnormal myotube contractures. The results from this investgation demonstrate that there are functional abnormalities in both dysgenic muscle and nervous tissues which are stable and expressed for up to 3 weeks in vitro.
Single fiber electromyography in the differential diagnosis of myopathic limb girdle syndromes and chronic spinal muscular atrophy
Authors: Shields Robert W. 
Published: January 2005

AbstractSingle fiber electromyography (SFEMG) of the extensor digitorum communis muscle was performed on 20 patients with either myopathic limb girdle syndromes (LGS) or chronic spinal muscular atrophy (CSMA) to assess its value in the differential diagnosis of these disorders. Neurologic examinations (muscle biopsies, standard electromyography, or both) were reviewed in 16 patients and resulted in diagnosing LGS in 11 patients and CSMA in 5 patients. In four patients, discordance between EMG and biopsy, or mixed features of myopathy and neuropathy in either test, resulted in an indeterminate diagnosis. Two groups were discerned from SFEMG, one with higher fiber density, jitter, and percentage of abnormal pairs consistent with neuropathy and another with lower values consistent with myopathy. In all 16 patiets, SFEMG confirmed the initial diagnosis, and in the four patients with indeterminate diagnoses, SFEMG suggested diagnoses of LGS in two patients and CSMA in two patients. Single fiber electromyography may be a useful diagnostic aid in the differential diagnosis of myopathic LGS and CSMA.
Nerve regeneration in exogenous cerebral ganglioside‐treated rats
Authors: Sebille Alain 
Published: January 2005

AbstractIntraperitoneal injection of 50 mg/kg of exogenous cerebral gangliosides resulted in a statistically significant (23%) increase (compared with saline‐injected controls) in the tetanic isometric tension of the rat plantaris muscle 7 days after section of the fourth lumbar root (L4). In a second experiment, intraperitoneal‐injected exogenous gangliosides were found to have no effect on axonal regeneration following cryoinjury to the sciatic nerve. These results lead to the possibility of an early enhancement of muscular collateral sprouting in partially denervated muscles under an intraperitoneal‐injected ganglioside mixture treatment.
Motor axon loop: An electroneurographic response
Authors: Roth G. , Egloff‐Baer S. 
Published: January 2005

AbstractA new kind of response to the stimulation of the median and ulnar nerves was observed in 10 patients. It is a motor unit showing a late latency in response to a weak stimulus and then suddenly a normal latency when the intensity is increased to a critical level. These two responses can be evoked at any level of a distinct nerve segment, the difference between their latencies being constant. The late response cannot be elicited below this segment and the normal response cannot be elicited above this segment. Its F‐latency is delayed and does not vary when the late response changes in a normal one. The conduction velocity along the axon seems normal. We propose the hypothesis of a motor axon loop along the nerve, with the recurrent portion traveling in the “grandes ellipses” or the classical anastomosis. These kinked axons are probably congenital; their frequency is still unknown.
Temperature sensitivity of tension development in a fast‐twitch muscle of the rat
Authors: Elmubarak Murtada H. , Ranatunga K. W. 
Published: January 2005

AbstractIsometric contractions of the biceps brachii (short head) muscle in the rat were recorded in vitro with direct stimulation and at different temperatures (range, 35°C–10°C). In confirmation of our previous findings from fast extensor digitorum longus and slow soleus muscles, the time and rate parameters of the twitch and the tetanus showed an increased temperature sensitivity below 20°C. The dependence on the initial muscle length of the rate of rise of tetanic tension was examined at 27°C and at 15°C. When represented as a percentage of the tetanic tension at each length, the rate of rise was independent of muscle length at both temperatures. Our interpretation of this particular observation is that the increased cooling depression of the rate of tension rise below 20°C is not associated with a qualitative change in its underlying basis.
Myofibrillar M‐line structure in normal and dystrophic hamster muscle
Authors: Eppenberger Monika E. , Schoenenberger Ronnie , Eppenberger Hans M. 
Published: January 2005

AbstractThe presence of the specific myofibrillar M‐line marker, myomesin, in isolated myofibrils and cryosections of skeletal and heart muscle as well as its appearance during differentiation in skeletal and heart muscle cell cultures of normal and dystrophic hamsters were evaluated. By means of the indirect immunofluorescence technique employing antibodies against chicken M‐line proteins, the appearance of antigen localized in the M‐line was investigated. No difference could be found between the M‐line structure of normal and dystrophic animals. The results suggest that the M‐line proteins, apparently relatively stable, are not primarily affected by the disease.
Differentiation in dystrophic muscle cultures from mice of different ages
Authors: Bryers Paul S. , Ecob Marion S. 
Published: January 2005

AbstractMuscle from dystrophic (129 ReJ dy/dy) mice, aged 1, 2, 3, 4, and 6 months, was cocultured with normal embryonic mouse spinal cord. Cultures were scored for regeneration (myotubes) and differentiation (cross‐striated or contracting fibers) over a 28‐day period. Although muscle from dystrophic mice of all ages was able to regenerate, the ability to differentiate decreased with the increasing age of the mouse. Muscle from litter‐mate control mice of different ages regenerated and differentiated equally well.
The clinical role of somatosensory evoked potential studies: A critical appraisal
Authors: Aminoff Michael J. 
Published: January 2005

AbstractThe clinical utility and limitations of somatosensory evoked potential (SEP) studies are reviewed. Somatosensory evoked potentials may help to identify a lesion in the sensory pathways, but do not indicate its nature. In multiple sclerosis subjects, the SEP findings may help to establish that there is a multiplicity of lesions, but multimodality evoked potentials abnormalities may occur in other disorders. Somatosensory evoked potential abnormalities do not reflect either the severity or the prognosis of cervical spondylosis and do not reliably permit early recognition of the totality of traumatic cord lesions, while the role of SEPs in monitoring cord function intraoperatively awaits definition. Somatosensory evoked potentials do not reliably indicate the individual prognosis after severe head injury, and discrepancies in published findings suggest that their use in the evaluation of brain death is premature. In hereditary spinocerebellar degenerations, SEP abnormalities may reflect central or peripheral pathology. Somatosensory evoked potentials can be used to determine conduction velocity in peripheral nerves and to identify inaccessible proximal lesions of these nerves, but the findings may lead to misleading conclusions about brachial plexus lesions, especially if pre‐ and postganglionic lesions coexist.
A morphometric study of intrafascicular vessels of mammalian sciatic nerve
Authors: Bell Mary A. , Weddell A. G. M. 
Published: January 2005

AbstractIntrafascicular vessel profiles were measured with a Quantimet image analyzer in 1‐μm transverse sections of sciatic nerves of rats and compared with those of (“white”) skeletal muscle. Blood vessels occupy the same percentage of the total tissue area in nerve and muscle tissues. The nerve, however, has much larger capillaries (about 1.7 ×) spaced farther apart (about 2.5 ×). Comparison of 3½ month with 1‐year‐old rats showed that muscle capillaries increased in diameter (slightly, but significantly) at maturity, but those of the nerve decreased (also significantly). Vascular percentages of total tissue areas did not change. Nerve and muscle samples from monkey, rabbit, mouse, and cat show that the same striking pattern of large, widely spaced vessels distinguishes the nerve from other tissues. Minor interspecies variations exist. The nerve may contain as much blood as the muscle but its angioarchitecture suggests a lower exchange capacity.
Elevated ammonia release from dystrophic chicken muscle cell and fibroblast cultures
Authors: Young Ronald B. , Hopkins Linda H. , Fleming George D. 
Published: January 2005

AbstractThe activity of adenosine monophosphate (AMP)‐aminohydrolase, the major NH3‐producing enzyme in skeletal muscle, was approximately 35% lower in 7‐day dystrophic muscle cell cultures than in normal muscle cells cultures. However, the release rate of NH3 from dystrophic muscle cells was 45% higher than that from normal muscle cells. The reasons for this apparent discrepancy are not clear. To determine indirectly if deamination of amino acids from protein degradation contributed to NH3 release, cells were incubated with 100 μg/ml of the protease inhibitor, leupeptin. Leupeptin reduced the rate of NH3 release by only 18.8% in normal muscle cells and 16% in dystrophic muscle cells. The release of NH3 was also higher from dystrophic chicken fibroblast cultures.