bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycogen cycle enzymes and cyclic nucleotides in avian muscular dystrophy
Authors: Schliselfeld Louis H. , Anderson Daryl M. 
Published: January 2005

AbstractFast‐frozen pectoralis muscle samples were taken from normal chickens (lines 200 and 412) and chickens having hereditary muscular dystrophy (line 304). The glycogen phosphorylase activity ratio (activity without AMP/activity with AMP) was significantly greater in dystrophic muscles (0.306 ± 0.046) than it was in normal muscles (0.090 ± 0.023). Glucagon treatment did not cause any changes in phosphorylase activity ratios. Isoproterenol treatment of both normal and dystrophic muscles raised the phosphorylase activity ratio of normal muscles to 0.446 ± 0.054, which was not significantly different from that of the dystrophic muscles. The dystrophic muscles had significantly less glycogen than normal muscles (23.3 ± 2.8 compared with 36.8 ± 2.8 μmoles glucosyl units/g of muscle). There was no relationship of muscular dystrophy to total phosphorylase activity (measured in the presence of 1 mM AMP) and to glycogen synthase activities measured without and with glucose 6‐phosphate. Normal muscles had 28% less cAMP and 49% less cGMP than dystrophic muscles, but these differences were eliminated by treatment of the chickens with glucagon.
Perineurioma as the cause of localized hypertrophic neuropathy
Authors: Mitsumoto Hiroshi , Wilbourn Asa J. , Goren Hershel 
Published: January 2005

AbstractClinical, electrodiagnostic, and morphological studies were performed on three patients with localized hypertrophic neuropathy (LHN). LHN is characterized clinically by slowly progressive motor mononeuropathy without significant pain or numbness. Nerve conduction studies and needle electrode examination show severe focal motor and sensory axonal loss. Morphological findings in the localized areas of enlarged nerves are different from those of generalized hypertrophic neuropathy, entrapment neuropathy, and neurofibroma, and consist of primary perineurial cell hyperplasia. The tumor is thus a perineurioma. This rare tumor can occur both in generalized neurofibromatosis and in isolated form and appears to be the cause of localized hypertrophic neuropathy.
Surface labeling studies of normal and dystrophic myogenic cells in culture
Authors: Schimmel Steven D. , Goff Richard 
Published: January 2005

AbstractSurface protein topographies of cultured normal and genetically dystrophic embryonic chick breast muscle cells and fibroblasts were compared by external labeling and size distribution analysis by sodium dodecyl sulfate‐polyacrylamide gradient slab gel electrophoresis. Four labeling techniques were evaluated and all were found to be specific for the cell surface. Using radioiodination of tyrosine residues and periodateborotritide labeling of sialic acid residues, no reproducible abnormalities could be detected in any of the dystrophic cell types—fibroblasts, fusion‐inhibited differentiated myoblasts, and multinucleated differentiated myotubes. However, comparison of 3‐day‐old cultures of normal fusion‐inhibited differentiated myoblasts with fused myotubes revealed that increased iodination of protein classes with nominal molecular weights of 230,000 and 88,000 was evident in the myoblasts. In addition, large structural differences were detected between differentiated myoblasts and myogenic cells grown in the presence of phorbol 12‐myristate 13‐acetate, a potent tumor promoter and reversible inhibitor of myogenic differentiation.
Spinal transection and the postnatal differentiation of slow myosin isoenzymes
Authors: Margreth A. , Libera L. Dalla , Salviati G. , Ischia N. 
Published: January 2005

AbstractNewborn rats underwent cordotomy, and the myosin composition of individual muscles was investigated 3 months postoperatively. The results indicate that, after cordotomy, the myosin composition in the extensor digitorum longus and tibialis anterior muscles is normal, whereas in the soleus muscle the myosin has catalytic and molecular properties intermediate between those of adult fast and slow myosin. Together with histochemical data these results indicate that spinal transection causes a developmental arrest in the soleus muscle, at a stage corresponding to a mixed fiber population.
Duchenne muscular dystrophy: Unusual activation of single fibers in vitro
Authors: Takagi Akio , Nonaka Ikuya 
Published: January 2005

AbstractSingle skinned fibers were prepared from muscle biopsies of patients with Duchenne muscular dystrophy (DMD) and other neuromuscular diseases. The activation of the contractile system by calcium or strontium ion and the function of the sarcoplasmic reticulum were studied. In many fibers of the biopsy specimens from patients with DMD, activation by strontium revealed a pattern intermediate between those shown by the usual type 1 and type 2 fibers. These fibers were generally of smaller diameter and produced less maximal tension than type 1 and 2 fibers. The study of muscle of newborn animals suggests that this unusual pattern of activation might reflect either arrested development or incomplete regeneration after muscle necrosis in the disease.
Supernormal excitability of human sensory fibers after ischemia
Authors: Stöhr M. , Gilliatt R. W. , Willison R. G. 
Published: January 2005

AbstractWeak electrical stimuli were applied to sensory fibers of the median nerve at the wrist, and the ascending action potentials were recorded at the elbow. This was done with or without a preceding conditioning stimulus to test for supernormal excitability to the second stimulus. In the resting nerve, supernormal excitability was present from 3 to 20 msec after a conditioning shock. After a period of ischemia, excitability was both exaggerated and prolonged. this observation confirms the presence in sensory fibers of a phenomenon previously described in motor fibers.
The role of proteases in experimental glucocorticoid myopathy
Authors: Clark Abbot F. , Vignos Paul J. 
Published: January 2005

AbstractMature, male, New Zealand white rabbits were treated with the synthetic glucocorticoid betamethasone (0.3 mg/kg body weight/day) for 2 weeks. The glucocorticoid treatment caused a 30% decrease in muscle weight of the type 2 psoas muscle, but had no apparent effect on the type 1 soleus muscle. Cathepsin D activity was elevated twofold in the psoas muscle of treated rabbits, a finding suggesting an active role for lysosomes in mediating muscle breakdown in glucocorticoid‐induced myopathy of the rabbit. There was no detectable alkaline serine protease activity in the muscles from either treated or control rabbits. Alkaline protease is localized in mast cells in some species, particularly the rat. Toluidine blue staining for mast cells was absent in rabbit muscles, a finding indicating that this species does not contain these cells. This protease, previously implicated in glucocorticoid myopathy, apparently plays no role in rabbit myopathy. There was no detectable elevation of the Ca‐activated protease in muscles from glucocorticoid‐treated animals. This finding suggests that if this protease plays a role in muscle degradation, its activity is controlled in vivo by special conditions (such as elevated CA levels, inhibitors, and compartmentalizations).
Congenital myasthenia: End‐plate acetylcholine receptors and electrophysiology in five cases
Authors: Vincent A. , Cull‐Candy S. G. , Newsom‐Davis J. , Trautmann A. , Molenaar P. C. , Polak R. L. 
Published: January 2005

AbstractThe nature of the defect in congenital myasthenia was investigated in biopsy specimens of intercostal muscle from 5 male patients whose symptoms presented between birth and 2 years of age. Miniature end‐plate potentials were reduced in amplitude in all 5 patients. The number of acetylcholine receptors as determined by α‐bungarotoxin binding was normal in case 1 and reduced in cases 2, 4, and 5. The shape of the endplates as shown by autoradiography and cholinesterase staining was normal in case 1 and elongated in cases 2, 4, and 5. In case 3, α‐bungarotoxin binding was slowly reversible, and there were some muscle fibers with multiple end‐plate regions. The acetylcholine content of the muscle was normal in all 5 cases. None of the patients had serum antibody to human acetylcholine receptor as measured by immunoprecipitation or inhibition of α‐bungarotoxin binding. We conclude that congenital myasthenia is a heterogeneous condition of nonimmune etiology in which both presynaptic and postsynaptic defects can be found.
Tellurium‐induced myelinopathy in adult rats
Authors: Said Gérard , Duckett Serge 
Published: January 2005

AbstractTellurium is known to induce a neuropathy in young rats but not in adult rats. In the present study adult rats were fed a diet containing 1.25% tellurium every day for 30 days. By the end of this period, the rats moved with difficulty but did not show paralysis. Study of teased nerve fiber preparations in conjunction with light and electron microscopy revealed myelin abnormalities consisting of myelin bubbling, segmental demyelination, and remyelination. In some animals, these abnormalities had a patchy distribution, affecting several adjoining nerve fibers in sciatic nerves, brachial plexus, and spinal roots. The intramyelinic edema sometimes was associated with splitting of the axons.
The significance of type 2C muscle fibers in duchenne muscular dystrophy
Authors: Nonaka Ikuya , Takagi Akio , Sugita Hideo 
Published: January 2005

AbstractUndifferentiated type 2C fibers, which are dark on ATPase staining with both alkaline and acid preincubation, comprised on average 16.1% of the muscle fibers in 12 patients with Duchenne muscular dystrophy (DMD). Many of type 2C fibers had characteristics of regenerating fibers: basophilic cytoplasm, vesicular nuclei with occasional prominent nucleoli, high alkaline phosphatase and nonspecific esterase activity, and also high oxidative enzyme activity at the periphery of the fiber. A localized high acetylcholinesterase activity suggested the presence of a neuromuscular junction in some of the type 2C fibers. In serial sections, histochemical reactions characteristic of the type 2C fiber were present in segments of a single fiber, which in other parts was either a type 1 or a type 2 fiber. Since most of the opaque (hyaline, dark) fibers, which previously have been thought to be precursors of necrotic fibers, behaved as differentiated type 1 or type 2 fibers, the presence of type 2C fibers in DMD may not reflect “dedifferentiation” of fiber type, but rather indicate an active regenerating process. It remains unknown whether the type 2C fiber segments in DMD develop into fully differentiated functional fibers or remain as incompletely regenerated fibers.
Chronic tetanus: Clinical report and histochemistry of muscle
Authors: Risk Winthrop S. , Bosch E. Peter , Kimura Jun , Cancilla Pasquale A. , Fischbeck Kenneth H. , Layzer Robert B. 
Published: January 2005

AbstractA patient who was partially immune to tetanus developed nonfulminant tetanus after a minor injury. Manifestations of the disease persisted for over 17 months. Electrophysiologic studies revealed an absent silent period in the masseter muscle, large‐amplitude F‐responses, and denervation. A muscle biopsy showed neurogenic atrophy with reinnervation. This observation supports the existence of chronic tetanus and provides morphologic evidence for a peripheral action of tetanus toxin in humans.
Vital‐freezing of human muscle cultures for storage and reculture
Authors: Carter Linda S. , Askanas Valerie 
Published: January 2005

AbstractThe vital‐freezing of human muscle cultures enabling long‐term storage in liquid nitrogen and future reculturing is described. Although human muscle is more fastidious in tissue culture than most cells of other origin, it was successfully frozen and re‐established in culture. Cultures re‐established after storage in liquid nitrogen differentiated and matured in the same way as primary human muscle cultures, and had the same histochemical and electron microsopic characteristics.
In vivo morphometric analysis of muscle microcirculation in dystrophic mice
Authors: Burch Thomas G. , Prewitt Russell L. , Law Peter K. 
Published: January 2005

AbstractIn order to test the vascular hypothesis of muscular dystrophy, the gracilis muscle in 6hyphen; to 7hyphen;weekhyphen;old C57BL/6Jhyphen;dy2J normal and dystrophic mice was studied using in vivo quantitative morphometric techniques to determine the total length and surface area of capillaries in which blood was flowing per unit volume of muscle. Individual capillary lengths, diameters, and red blood cell velocities were also quantified. During resting conditions, the capillary density (length per unit volume of muscle) and surface area are increased significantly in dystrophic muscle compared to normal muscle. Under fully vasodilated conditions, the capillary density and surface area are similar in normal and dystrophic muscle. Individual capillary lengths, diameters, and red blood cell velocities are also similar in normal and dystrophic muscle under resting conditions. These results indicate that, contrary to the vascular hypothesis, dystrophic muscle at rest has increased capillary density, surface area, and blood flow. It is postulated that the increased capillary density in dystrophic muscle at rest is secondary to muscle fiber breakdown.
Protonmotive force in muscle mitochondria
Authors: Stumpf David A. , Haas Richard , Eguren Luis A. , Parks Janice K. , Eilert Robert E. 
Published: January 2005

AbstractThe protonmotive force (Δp) of muscle mitochondria was measured by estimating the distribution of 14C‐labeled TPMP (trimethylphenylphosphonium iodide) and 14C‐labeled acetate across the inner membrane of muscle mitochondria. The matrix volume was simultaneously determined using 3H‐labeled H2O and 3H‐labeled mannitol and repeated drying to distinguish the label in these 2 compounds. Rapid separation of mitochondria from the incubation medium by centrifugation through silicone oil avoids the problems of potential anaerobic conditions associated with conventional centrifugation and large volumes of trapped media associated with filtration. The value for Δp (mean ± SD) was 192 ± 26 mV in 30 determinations with rat muscle mitochondria during state 4. Measurement of oxygen consumption allowed calculation of membrane conductance (Cm, H+) which was 0.49 ± 0.18 nmol of H+/min/mg protein/mV. The values for δp and Cm, H+ are reported for a variety of experimental conditions and are consistent with Mitchell's chemiosmotic theory. Biopsy specimens obtained from human muscle gave state‐4 Δp values of 197 ± 30 mV (n = 5) and Cm, H+ values of 0.52 ± 0.12 nmol of H+/min/mg/mV (n = 4). This Δp assay is the first described for coupled mammalian muscle mitochondria and will be useful in assessing membrane function.
Gangliosides and sialoglycoproteins in normal and denervated rat diaphragm muscle
Authors: Inestrosa Nibaldo C. , Fernandez Hugo L. 
Published: January 2005

AbstractGanglioside‐ and glycoprotein‐bound sialic acid in endplate and non‐endplate regions of rat diaphragm muscles were assessed 1–16 days after phrenic nerve transection. Sialic acid in glycoproteins (90% of total) and gangliosides (10% of total) from intact hemidiaphragms was distributed uniformly throughout endplate and nonendplate regions. After denervation, the total sialic acid per hemidiaphragm increased (days 1–4) and reached a maximum level (days 8–12) which remained constant (days 12–16). These sialic acid changes reflected increments in gangliosides (40% over control), which occurred simultaneously in endplate and nonendplate regions (days 1–8), and increments in sialoglycoproteins (70%–80% over control), which took place much earlier in endplate (days 1–8) than in nonendplate (days 8–14) regions. The results of this study, together with previous data, favor the hypothesis that maintenance of both sialoglycoproteins and gangliosides depends upon an intact innervation, probably through separate mechanisms involving different neurogenic factors.
Histochemical staining of the acetylcholine receptor, acetylcholinesterase, and the axon terminal
Authors: Bjornskov Elizabeth K. , Norris Forbes H. , Mower‐Kuby Janis 
Published: January 2005

AbstractFluoresceinated alpha‐bungarotoxin (α‐BT) and the Pestronk‐Drachman neuromuscular stain were combined to demonstrate the acetylcholine receptor, the junctional acetylcholinesterase, and the nerve terminal on the same endplate. The method is reliable and rapid. Synapses in both normal muscle and muscle affected by amyotrophic lateral sclerosis (ALS) are equally well displayed.
Normal function in sarcoplasmic reticulum from mice with muscular dystrophy
Authors: Mrak Robert E. , Fleischer Sidney 
Published: January 2005

AbstractA rapid, gentle technique has been developed for the isolation of sarcoplasmic reticulum (SR) from small amounts of skeletal muscle from normal and dystrophic mice. Assays for mitochondrial and surface membrane marker enzymes revealed only low levels of contamination in the isolated fractions. A small amount of calcium‐insensitive (“basal”) ATPase in the normal preparation and a higher value in the dystrophic were shown to be due to contamination by a lighter membrane fraction of probable surface membrane origin. Isolated SR from normal and dystrophic mice were indistinguishable by thin section and freeze‐fracture electron microscopy. Only small differences in calcium loading rates and capacity, and in calcium‐stimulated ATPase activity, were present. These were attributable to small differences in purity. We conclude that there is no difference in SR from normal and dystrophic mice in the properties measured.
Chronic elevation of endoneurial fluid pressure is associated with low‐grade fiber pathology
Authors: Low Phillip A. , Dyck Peter James , Schmelzer J. D. 
Published: January 2005

AbstractThe effects of chronic elevations of endoneurial fluid pressure (EFP) on mammalian nerve fibers were studied using a modified model of experimental galactose neuropathy. Fiber pathology was monitored by the sensitive method of grading the pathologic abnormalities of single teased fibers. Prominent edema was produced in rats poisoned with combined oral and parenteral galactose. EFP and fascicular size were markedly elevated and tibial nerve conduction velocity was reduced. We have demonstrated, for the first time, the presence of fiber degeneration in galactosefed rats. Possible mechanisms of nerve fiber damage include: (1) impaired capillary circulation and increased fiber separation secondary to increased EFP and edema, respectively; (2) increased endoneurial hyperosmolarity, which is known to cause changes in fiber shape; and (3) unknown metabolic derangement of axons. Because much higher rates and different types of fiber pathology are encountered in lead and hexachlorophene intoxication having comparable degrees of EFP, one cannot attribute the fiber pathology directly to the raised EFP in these latter neuropathies.
Perineuritis in mononeuritis multiplex with cryoglobulinemia
Authors: Konishi Tetsuro , Saida Kyoko , Ohnishi Akio , Nishitani Hiroshi 
Published: January 2005

AbstractA case with mononeuritis multiplex associated with mixed cryoglobulinemia and mild persistent hepatitis is reported. Sural nerve biopsy specimens revealed thickening of the perineurium and vascular alterations with inflammatory cells infiltrating into the perineurium as well as the epineurium and endoneurium, thus having the features of perineuritis. Most myelinated and unmyelinated nerve fibers were lost. A therapeutic trial of corticosteroids decreased the serum titer of cryoglobulin without any improvement of clinical features.
Pathophysiology of fasciculations in ALS as studied by electromyography of single motor units
Authors: Conradi Sebastian , Grimby Lennart , Lundemo Gunnar 
Published: January 2005

AbstractElectromyographic potentials of fasciculations were studied in ten patients with amyotrophic lateral sclerosis (ALS). The EMG recordings were made from the extensor digitorum brevis muscle. The EMG recording was so selective that only one motor unit potential appeared on maximal voluntary effort and on supramaximal electrical stimulation of the peroneal nerve. In a series of fasciculations, the shapes of the EMG potentials varied, while in a series of voluntary twitch activations of electrical nerve stimulations the EMG potentials were mainly constant. Fasciculations were followed by antidromic impulses in the test unit axon as judged from collision tests, and they persisted after lidocaine blockades of the nerve to the muscle. The findings are compatible with a conclusion of distal multifocal triggering of fasciculation. Fasciculating motor units had voluntary firing properties close to those of normal low‐threshold motor units. Widespread fasciculations were abolished by a nonparalytic dose of a synthetic curare derivative (Pavulon) and augmented by administration of neostigmine in two cases. The fasciculations in ALS thus have the same characteristics as experimental fasciculations evoked by cholinesterase inhibitors, and there is reason to believe that the underlying pathophysiological mechanism is similar in the two cases.
Necrosis of capillaries in denervation atrophy of human skeletal muscle
Authors: Carpenter Stirling , Karpati George 
Published: January 2005

AbstractGastrocnemius muscles from eight adults with moderate to severe denervation of various causes (excluding vascular diseases), along with biopsy specimens from seven controls, were studied in semithin epoxy resin sections and by electron microscopy. Morphometry showed diminution in the number of capillaries per muscle fiber roughly proportional to the degree of muscle fiber atrophy. The number of capillaries per transverse muscle fiber area tended to increase. By phase microscopy, destroyed capillaries were found in all denervated muscle specimens. Denervated muscle becomes relatively overvascularized, and probably as a result, some capillaries become necrotic. This tends to restore the normal equilibrium between muscle mass and blood supply. The capillary changes of denervation can be distinguished from those in dermatomyositis.
Microgravimetric analysis of nerve edema
Authors: Costello M. L. , Powell H. C. , Myers R. R. 
Published: January 2005

AbstractA technique for microgravimetric analysis of nerve edema was used to demonstrate increased water content in hexachlorophene neuropathy. The method was modified from one used previously to quantify brain edema by using density gradient columns prepared with two nonaqueous fluids of high and low specific gravity. This method revealed a wide separation between hexachlorophene‐treated and control nerves, Gradient position was then related to specific gravity, which averaged 1.03426 in hexachlorophene‐treated nerves versus 1.04921 for control nerves. This, in turn, was correlated with the percentage of water in the tissue. Water content of hexachlorophene‐intoxicated nerves was approximately 10% greater than control nerves. A major advantage of this technique is its sensitivity in detecting edema in small tissue samples.