bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chloroquine‐induced cytosomes with curvilinear profiles in muscle
Authors: Neville Hans E. , Maunder‐Sewry Caroline A. , McDougall Jennifer , Sewell John R. , Dubowitz Victor 
Published: January 2005

AbstractA patient with systemic lupus erythematosus (SLE) was treated with chloroquine therapy for four years after the onset of her illness. Nine years after cessation of chloroquine, muscle weakness developed as part of the SLE. Four muscle biopsies performed for diagnostic purposes revealed varying degrees of inflammatory change as well as distinctive cytosomes with curvilinear profiles (CCPs). These CCPs were identical to those reported in Batten disease, a degenerative disorder of children which has a clinical course different from SLE. The CCPs seen in this case of SLE are thought to result from the effect of chloroquine on membrane systems within muscle cells. This report calls attention to the fact that CCPs are not unique to Batten disease but may also occur in muscle of SLE patients treated with chloroquine.
The importance of serum pyruvate kinase in neuromuscular diseases and carrier states
Authors: Sage Jacob , Inati Yakub , Samaha Frederick 
Published: January 2005

AbstractSerum pyruvate kinase activity was measured in several myopathic and denervating illnesses as well as in 86 potential carriers of Duchenne dystrophy. These data showed that in potential Duchenne carriers, the serum pyruvate kinase assay is more sensitive in younger patients, especially those under 20 years of age.
Motor neuron firing range, axonal conduction velocity, and muscle fiber histochemistry in neuromuscular diseases
Authors: Borg J. , Grimby Lennart , Hannerz Jan 
Published: January 2005

AbstractThe voluntary discharge properties and axonal conduction velocity of single motor units were studied in patients with neuromuscular diseases with retained differentiation of the muscle fibers into type 1 and type 2, and in patients with late‐onset hereditary distal myopathy in which muscle fibers have only intermediate histochemical properties. In the patients with muscle fiber differentiation, the findings were similar to those in normal subjects; that is, there was a continuum between motor units which fired tonically at low rates and had a low axonal conduction velocity, and motor units which fired phasically at high rates and had a high axonal conduction velocity. In the patients without muscle fiber differentiation, all motor units had intermediate firing properties and a low axonal conduction velocity. It is suggested that in chronic pathologic states, the differentiation of the muscle fiber histochemistry remains only as long as the differentiation of the motor neurons remains.
Types of human intrafusal muscle fibers
Authors: Kucera Jan , Dorovini‐Zis K. 
Published: January 2005

AbstractThe histochemical and fine structural profiles of human intrafusal muscle fibers were studied. Spindles were located in freshly frozen specimens taken from biopsied normal external intercostal muscles, and periodic 10‐ and 50‐μm‐thick cross sections were processed alternately for enzyme histochemical and electron microscopic examination. Nuclear bag fibers were of two types, bag1 and bag2, histochemically, and they displayed two distinct types of ultrastructure. Nuclear chain fibers were histochemically and ultrastructurally homogeneous. Regional differences in enzymatic staining and ultrastructure occurred along individual intrafusal fibers. Human bag1 and bag2 fibers appear to be analogous to the two types of nuclear bag fiber identified in animal spindles and are considered to have different roles in spindle function. The presence of three types of intrafusal fibers should be taken into account when studying spindle abnormalities in human neuromuscular disorders.
Physical probes of biological membranes in studies of the muscular dystrophies
Authors: Barchi R. L. 
Published: January 2005

AbstractThis review deals with recent physical approaches to the study of biomembranes. First, current concepts of the structure and dynamic organization of biological membranes are considered. The theoretical basis and practical application of various physical probe techniques are then discussed with specific reference to their usefulness in studies of these membranes. Particular emphasis is given to electron spin resonance and fluorescence techniques and to the potential difficulties encountered in their use and interpretation. Finally, reports applying these physical probes to various aspects of the human muscular dystrophies are reviewed and our current information in this area is summarized.
Facilitatory effects of 4‐aminopyridine on neuromuscular transmission in disease states
Authors: Kim Yong I. , Goldner Marcia M. , Sanders Donald B. 
Published: January 2005

AbstractThe in vitro effects of 4‐aminopyridine (4‐AP) on neuromuscular transmission were determined by microelectrode techniques in intercostal muscles from patients with myasthenia gravis (MG) and the Eaton‐Lambert syndrome (ELS), and in forelimb muscles from rats with experimental autoimmune myasthenia gravis (EAMG). In MG and EAMG, the amplitudes of miniature endplate potentials (MEPPs) and endplate potentials (EPPs) were reduced, and there was increased sensitivity to the blocking action of d‐tubocurarine (dTc). In ELS, MEPP amplitude was normal but the average number of acetylcholine quanta released by nerve impulses was reduced, causing subthreshold EPPs. In EAMG muscle, 4‐AP produced dose‐dependent increases in EPP amplitude and in the duration of indirectly elicited muscle action potentials but no changes in MEPP amplitude and resting membrane potential. 4‐AP completely reversed the postsynaptic blockade produced by dTc and EAMG. 4‐AP appears to facilitate neuromuscular transmission in EAMG, MG, and ELS by increasing the neurally evoked transmitter release, thus overcoming either the pre‐ or the postsynaptic neuromuscular blockade.
Peripheral neuropathy associated with disulfiram administration
Authors: Olney Richard K. , Miller Robert G. 
Published: January 2005

AbstractVery few cases of peripheral neuropathy as a complication of disulfiram therapy have been described. The clinical and electrodiagnostic features of two patients who developed a severe peripheral neuropathy during disulfiram administration are reported. Evidence is presented which suggests that disulfiram causes a dying‐back axonal neuropathy.
Chloride efflux measurements in mammalian skeletal muscle
Authors: Hayward B. S. , Barchi R. L. 
Published: January 2005

AbstractA rapid sampling technique has been used to resolve the components of 36Cl efflux from isolated extensor digitorum longus (EDL) muscles of young rats. Four distinct fluxes with apparent rate constants of 4.40 ± 0.02 min−1 (k1), 1.30 ± 0.04 min−1 (k2), 0.24 ± 0.04 min−1, (k3), and 0.048 ± 0.05 min−1 (k4) at 30°C were identified. Together, these fluxes accounted for the movement of more than 98% of exchangeable muscle chloride (Cl) ions. The muscle compartment associated with the fastest flux (k1) contained 23% ± 2% of the total muscle Cl corresponding to the extracellular space as determined with inulin or mannitol. The compartment associated with k2 accounted for 71% of the intracellular volume, and k2 was assumed to represent 36Cl efflux across the surface membrane. The rate constant k2 was temperature‐dependent with a Q10 of 1.11 between 5°C and 30°C. Acromatic carboxylic acids known to block sarcolemmal Cl conductance (Gcl) specifically lowered k2 by 25% at 30°C, as did replacement of external Cl with nitrate.
Genetics of congenital nemaline myopathy
Authors: Kondo Kiyotaro , Yuasa Tatsuhiko 
Published: January 2005

AbstractFamily patterns for 50 reported probands with congenital nemaline myopathy were compared with expected patterns derived from various possible genetic hypotheses. The disease had a high mortality in childhood but remained clinically stationary after this period. Some normal relatives showed nemaline rods on muscle biopsy. Chromosomes were normal in the two cases in which they were examined. Prenatal exposures appeared irrelevant to this disease. Autosomal recessive and X‐linked recessive or dominant modes of inheritance were not compatible with the observed patterns, which could be explained by an autosomal dominant mode with a reduced penetrance. Normal relatives who carried rods were presumably unaffected heterozygotes of the same gene. The genetic ratio (the proportion of affected siblings) was 0.3, being short of the expected value, 0.5, probably because of the presence of these asymptomatic rod‐bearing heterozygotes. While the pressure of natural selection was great in the patients who died or were severely disabled, the gene could be passed to the next generation by mildly affected patients or heterozygotes who remained unaffected.
On the ultrastructure of primary cultures of normal and dystrophic hamster tongue muscle
Authors: Thakar J. H. , Thede A. , Strickland K. P. 
Published: January 2005

AbstractPrimary cultures, prepared from the tongue muscle of 1‐day‐old normal and dystrophic (UM‐X7.1 strain) hamsters, were examined under the electron microscope after 6 to 8 days in vitro when myotube development was in progress. Myotubes from normal tongue showed development similar to that of muscle of other tissues and species grown in culture. Compared to myotubes of normal cultures, those of dystrophic cultures showed a number of differences. The sarcoplasmic reticulum and mitochondria showed areas of dilation or swelling and poor development. The density of ribosomes and polyribosomes was less, Z‐band formation was primitive or absent, myofibrillar formation was less, and its organization was poor. Also, spontaneous contractions in dystrophic myotubes were few and irregular. These differences agree well with those reported for heart cells from the dystrophic (cardiomyopathic) hamster grown in culture.
Disorders of lipid metabolism in muscle
Authors: Di Mauro Salvatore , Trevisan Carlo , Hays Arthur 
Published: January 2005

AbstractAt rest and during sustained exercise, lipids are the main source of energy for muscle. Free fatty acids become available to muscle from plasma free fatty acids and triglycerides, and from intracellular triglyceride lipid droplets. Transport of long‐chain fatty acyl groups into the mitochondria requires esterification and de‐esterification with carnitine by the “twin” enzymes carnitine palmityltransferase (CPT) I and II, bound to the outer and inner faces of the inner mitochondrial membrane. Carnitine deficiency occurs in two clinical syndromes. (1) In the myopathic form, there is weakness; muscle biopsy shows excessive accumulation of lipid droplets; and the carnitine concentration is markedly decreased in muscle but normal in plasma. (2) In the systemic form, there are weakness and recurrent episodes of hepatic encephalopathy; muscle biopsy shows lipid storage; and the carnitine concentration is decreased in muscle, liver, and plasma. The etiology of carnitine deficiency is not known in either the myopathic or the systemic form, but administration of carnitine or corticosteroids has been beneficial in some patients. “Secondary” carnitine deficiency may occur in patients with malnutrition, liver disease, chronic hemodialysis, and, possibly, mitochondrial disorders. CPT deficiency causes recurrent myoglobinuria, usually precipitated by prolonged exercise or fasting. Muscle biopsy may be normal or show varying degrees of lipid storage. Genetic transmission is probably autosomal recessive, but the great male predominance (20/21) remains unexplained. In many cases, lipid storage myopathy is not accompanied by carnitine or CPT deficiency, and the biochemical error remains to be identified.
Normal and dystrophic embryonic chicken pectoralis muscle cultures: I. Cell differentiation, protein synthesis, and enzyme levels
Authors: Young Ronald B. , McConnell David G. , Suelter Clarence H. , Phillips Teresa A. 
Published: January 2005

AbstractNormal (line 200) and dystrophic (line 307) embryonic chicken pectoralis muscle cells were studied in cell culture over a period of 2 weeks. During the first 4 days, normal and dystrophic cultures exhibited similar developmental increases in the number of nuclei within multinucleated myotubes; however, dystrophic muscle cells degenerated approximately twice as fast as normal cells once the initial burst of myoblast fusion was complete. The apparent synthesis rate of nonmyofibrillar proteins was similar in normal and dystrophic cells throughout development, but the apparent synthesis rates of myosin heavy chain and the myofibrillar protein fraction were 50%–90% higher in dystrophic muscle cultures once maturity had been reached (days 6–14). The specific activities of creatine kinase and phosphofructokinase were not affected by the dystrophic condition; however, specific activity of AMP‐deaminase was depressed 25%–40% in the dystrophic muscle cultures.
Normal and dystrophic embryonic chicken pectoralis muscle cultures: II. Ultrastructural comparison
Authors: McConnell David G. , Young Ronald B. , Suelter Clarence H. 
Published: January 2005

AbstractUltrastructural comparison was made between dystrophic and normal chicken breast muscle cells which had been isolated from 12‐day‐old embryos and cultured for up to 14 days. All electron microscopic examinations were conducted in the absence of any knowledge as to the dystrophic or normal origin of the cells, or the day on which the cells had been harvested from culture. The same blind procedures were applied to attempts to reconstruct from electron micrographs the correct sequence of days for a particular experiment and to identify the origin of the cells as normal or dystrophic. No consistent differences between normal and dystrophic cells were apparent either in extent of differentiation, such as the formation of mature sarcomeres, or in degenerative properties, such as disintegrating mitochondria, lipid aggregations, or extracellular debris. In light of metabolic and developmental differences in these cultures, the absence of ultrastructural differences was attributed in part to the presence of cells with widely different degrees of integrity, differentiation, and degeneration in both normal and dystrophic cultures.
Normal and dystrophic embryonic chicken pectoralis muscle cultures: III. Viral infection of normal cell cultures
Authors: McConnell David G. , Gardner M. Elizabeth , Tuomari Anne V. , Young Ronald B. , Suelter Clarence H. 
Published: January 2005

AbstractTwelve‐day normal and dystrophic chick embryo breast muscle cells were cultured for up to 14 days, using normal embryo extract in the culture medium. Fluorodeoxyuridine was added on day 3 to suppress fibroblast overgrowth. Three of 6 experiments with normal cells were severely infected with avian leucosis/sarcoma (ALS) virus particles. The findings appear to lend support to the suggestion that the ALS virus is a mitochondriophage. Infected cultures demonstrated a depressed rate of total protein synthesis as reflected by incorporation of [3H]leucine. Extractable protein and total protein content were also depressed within several days after ALS particles were identified. These findings reinforce caution in acceptance of the common assumption that viral infections are an unavoidable and metabolically benign component of muscle cell cultures.
Growth of neonatal hamster skeletal muscle in culture
Authors: Tautu Constantin , Jasmin Gaëtan , Solymoss Béla C. 
Published: January 2005

AbstractQuantitative procedures for cell dissociation, selective plating, and growth conditions were adapted to neonatal hamster muscle in order to obtain cultures with a predictable evolution and sufficient differentiated myofibers. Normal and myopathic cultures were compared with regard to cell yield, myogenic cell fusion, and muscle differentiation. This technique is proposed for comparative studies of in vitro myogenesis in normal and myopathic hamsters.
Creatine kinase isozyme transition in chicks with hereditary muscular dystrophy
Authors: Stewart Patricia A. , Percy Maire E. , Chang Lebe S. , Thompson Margaret W. 
Published: January 2005

AbstractIn both normal chicks and chicks with hereditary muscular dystrophy the BB (brain) and MB (hybrid) isozymes were the predominant forms of creatine kinase (CK) activity in embryonic skeletal muscle. As myogenesis progressed, activity due to the MM (muscle) isozyme progressively increased, and by 1 week ex ovo, the MM isozyme accounted for approximately 97% of total muscle activity in both genotypes. During this time, the proportion of the MM isozyme was slightly but significantly lower in dystrophic muscles. After hatching the proportion of the MB isozyme and its total activity decreased in normal muscle, but increased in dystrophic pectoral muscle, and by 5 months ex ovo, the MB isozyme accounted for 10% of total CK activity. Prior to hatching there was no consistent difference in total CK activity between normal and dystrophic tissues, but by 1 week after hatching and thereafter, total CK activity was significantly lower in dystrophic pectoral muscle.
Disorders of neuromuscular transmission other than myasthenia gravis
Authors: Swift Thomas R. 
Published: January 2005

AbstractDisorders of neuromuscular transmission in humans are caused by a wide variety of agents including systemic diseases, drugs, environmental toxins, animal envenomation, cations, and hormones. Some are genetically determined. Many are of unknown etiology. All such disorders interfere with one or more events in the sequence whereby a nerve impulse excites a muscle action potential. In many disorders of neuromuscular transmission, abnormal fatigue occurs, and some cases respond dramatically to treatment. Investigation of the microphysiology, microanatomy, and pharmacology of both normal and diseased neuromuscular junctions has increased our knowledge of these disorders.
Activity, molecular forms, and cytochemistry of cholinesterases in developing rat diaphragm
Authors: Brzin Miro , Sketelj Janez , Tennyson Virginia M. , Kiauta Tomaz , Budininkas‐Schoenebeck Mary 
Published: January 2005

AbstractAcetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were studied in the diaphragm of early postnatal rats, using radiometric determination of enzyme activities, velocity sedimentation for separation of molecular forms, and electron microscopic cytochemistry to localize enzymes. AChE activity did not change significantly during the first 2 months after birth. The level of 16 S AChE was high at early stages, but decreased to adult levels between days 19 and 32 after birth. In newborn and 8‐day‐old rats, 16 S and 13 S AChE were present in both endplate and extrajunctional muscle. In newborn muscle, BuChE activity was higher than AChE activity, but decreased 6‐fold by day 32. Newborn muscle contained 16 S, 10 S, and 4 S BuChE. The principal form throughout development was 4 S BuChE, but all forms diminished as total BuChE activity decreased with maturation. At early postnatal neuromuscular junctions, end product of both AChE and BuChE was present in the cleft, as well as in Schwann cells. More Schwann cells were present in early stages than in later stages, and this might account for part of the later decrease of BuChE activity measured biochemically.
Biochemical functioning of mitochondria in normal and denervated mammalian skeletal muscle
Authors: Joffe Maureen , Savage Nerina , Isaacs Hyam 
Published: January 2005

AbstractMitochondrial preparations derived from denervated rat skeletal muscle and paired control muscle are characterized with respect to their oxidative and phosphorylative capacities. Our data indicate that there is an impairment within the first 2 energy coupling regions of the respiratory chain and within the ATPase complex itself.
Lupus myositis
Authors: Foote Robert A. , Kimbrough Stephen M. , Stevens J. Clarke 
Published: January 2005

AbstractEleven patients met rigid criteria for having both polymyositis and systemic lupus erythematosus (SLE). The patients differed little in clinical features when compared with patients who had SLE and polymyositis in a previously reported series. The overall mortality rate of 18% and the finding that 56% of survivors were asymptomatic at latest follow‐up (average four years) suggest that the prognosis for this subgroup of patients may be more favorable than that for patients with rheumatoid arthritis and scleroderma complicated by polymyositis and may be comparable to the prognosis of the overall group of patients with polymyositis.
Muscle histochemistry in congenital muscular dystrophy with central nervous system involvement
Authors: Nonaka Ikuya , Sugita Hideo , Takada Kuniyasu , Kumagai Komei 
Published: January 2005

AbstractMuscles from 13 patients with clinical characteristics of congenital muscular dystrophy and central nervous system involvement (Fukuyama type) (FCMD) were examined using morphometric and fiber type analysis. The muscles from patients aged 5 months to 3 years demonstrated small‐calibered fibers with increased variation in fiber size, connective tissue proliferation, and scattered necrotic and regenerating fibers. Groups of atrophic fibers were absent. Both type 1 and type 2 fibers were affected, though type 1 fibers predominated and type 2B fibers decreased as the disease progressed. The muscle changes were apparently progressive, affecting not only the limbs but also the intercostal, diaphragm, and cardiac muscles. Although there was no qualitative difference in the muscle histochemistry between FCMD and Duchenne muscular dystrophy (DMD), there was a greater proportion of type 2C fibers and fibrosis was present at the early infantile stage of FCMD.
Myotonic muscular dystrophy: Morphology, histochemistry, and growth characteristics of cultured skin fibroblasts
Authors: Hartwig Geoffrey B. , Miller Sara E. , Frost Arlo P. , Roses Allen D. 
Published: January 2005

AbstractThe genetic defect in myotonic muscular dystrophy (MyD) is expressed in several tissues. Evidence of the expression of this defect in MyD fibroblasts was sought by comparing them with normal fibroblasts. Reports describing increased alcianophilia and metachromasia in MyD fibroblasts could not be confirmed. Furthermore, no differences were observed with phase contrast microscopy or scanning and transmission electron microscopy, in histochemical studies, in growth characteristics, or in 35S‐sulfate incorporation studies.
Electrical stimulation of denervated muscle prevents decreases in oxidative enzymes
Authors: Nemeth Patti M. 
Published: January 2005

AbstractThe influence of muscular contraction on the oxidative enzymes and the diameters of muscle fibers was investigated. Soleus muscles of guinea pigs were denervated for four weeks. The denervated fibers showed a reduction in the intensity of staining for β‐hydroxybutyrate dehydrogenase, cytochrome oxidase, succinate dehydrogenase, and NADH‐dependent tetrazolium reductase. Denervation also resulted in a decrease in fiber diameter. Denervated soleus muscles were electrically stimulated to contract over a four‐week period at a frequency normally received by slow contracting muscles. Electrical stimulation caused the stain intensity of histochemical reactions for oxidative enzymes to appear to be normal or greater than normal in 90% of the denervated fibers. Stimulation also caused 69% of the denervated fibers to be of normal or greater than normal size. The results demonstrate that contraction of denervated muscle by electrical stimulation prevents the loss of oxidative enzymes and the atrophy associated with denervation.