bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple forms of anti‐acetylcholine receptor antibody in myasthenia gravis
Authors: Mittag Tom , Massa Tobias , Kornfeld Peter , Papatestas Angelos , Bender Adam , Genkins Gabriel
Published: January 2005

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

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

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

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

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

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

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

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

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

In rats treated biweekly with 20,25‐diazacholesterol (200 mg/kg orally), the desmosterol level in skeletal muscle sarcolemma increased progressively to about 80% of membrane sterol while total sterol levels remained constant. Following a single oral dose of 20,25‐D, the kinetics of desmosterol accumulation and subsequent loss in sarcolemma were more rapid than in whole muscle homogenates. The anisotropy of diphenylhexatriene fluorescence and the calculated microviscosity of the probe's microenvironment decreased significantly with increasing desmosterol levels in a temperature‐dependent manner, although fluorescent lifetimes were not altered. Fluorescent probes which localize in more superficial regions of the membrane detected no change. Studies with erythrocyte ghost membranes yielded results comparable to sarcolemma. Replacement of membrane cholesterol with desmosterol reduced the local microviscosity of the membrane hydrophobic region associated with phospholipid acyl chains and sterol side chains, but had little apparent effect on more superficial, polar regions. These observations can be correlated with the membrane location of the unsaturated side chain in desmosterol.
The epidemiology of motor neuron disease in Scotland
Authors: Holloway Susan M. , Emery Alan E. H.
Published: January 2005

A study was made of the frequency of motor neuron disease in Scotland. The frequency of the disease was about the same as in most other countries of the world, but it may be increasing in Scotland. Individuals resident in the north and east of the country and those engaged in agricultural work were found to have an increased risk of developing the disease. It is suggested that motor neuron disease might be related to the use of insecticides or may result from a persistent viral infection.
Variability in nerve biopsy findings in a kinship with dominantly inherited charcot‐marie‐tooth disease
Authors: van Weerden Tiemen W. , Houthoff Hendrik Jan , Sie Onggie , Minderhoud Jan M.
Published: January 2005

A large kinship with an autosomal hereditary‐motor‐and‐sensory‐neuropathy (HMSN) form of Charcot‐Marie‐Tooth disease (CMTD) is described. The affected members have the clinical features and reduced motor nerve conduction velocities of the hypertrophic type of CMTD, or HMSN I. Biopsies of the sural nerves of five affected members showed a large variability of demyelination and remyelination and onion bulb formation, independent of axonal atrophy and the severity of the disease. These findings are discussed in relation to recent literature.
The influence of testosterone on neuromuscular transmission in hormone sensitive mammalian skeletal muscles
Authors: Souccar Caden , Lapa Antonio José , do Valle José Ribeiro
Published: January 2005

The influence of testosterone on neuromuscular transmission was studied in levator ani (LA) and extensor digitorum longus (EDL) muscles taken from normal rats, castrated rats, and castrated rats treated with testosterone. Thirty days after castration LA muscle weights were reduced by 60%, but the frequency and amplitude of the miniature end‐plate potentials (mepps) were increased by 40% and 50%, respectively. The weights and mepp frequencies of the EDL muscles were not altered after castration, but the mepp amplitudes increased by 30%. The quantal content of the endplate potentials was not affected in either muscle. Administration of testosterone to the castrated rats prevented such changes in the LA muscles. The results indicate that castration of adult rats affects the spontaneous transmitter release in both muscles, but the changes are more pronounced in the levator ani, which is a target muscle for testosterone.
The diagnostic yield of quantified electromyography and quantified muscle biopsy in neuromuscular disorders
Authors: Buchthal Fritz , Kamieniecka Zofia
Published: January 2005

Electromyography (EMG), histology, and histochemistry were related in 264 patients with neuromuscular disorders classified according to history and clinical and other laboratory findings. Electromyography and histological and histochemical abnormalities were divided in specific and nonspecific criteria. Specific histochemical criteria alone identified 28% of neurogenic lesions. Criteria of myopathy, obtained from the pattern of electrical activity during 30% of maximal effort, helped to delineate a myopathy when the only abnormality was an increased incidence of polyphasic potentials together with a pattern of full recuitment during maximal effort. Histology, histochemistry, or both, and EMG were concordant with clinical findings in 77% of 188 patients with myopathy and in 91% of 64 patients with neurogenic lesions. The electromyogram was concordant with the clinical classification in 87% of patients with myopathy and in 91% of patients with neurogenic impairment. The biopsy was in agreement with or contributed to the classification in 79% of patients with myopathy and in 92% of patients with neuropathy.
Prevention of skeletal muscle fiber necrosis in hamster dystrophy
Authors: Karpati George , Carpenter Stirling , Prescott Steven
Published: January 2005

Necrosis and widespread central nucleation of skeletal muscle cells, which are the main features of skeletal muscle pathology in genetically dystrophic hamsters (UMX‐7.1 strain), were not present in muscles of 45‐ to 65‐day‐old animals which had been surgically denervated at 15 to 18 days of age. Necrosis and widespread central nucleation were also absent in hind leg muscles at 30 to 60 days of age after transection of the high thoracic spinal cord at 15 to 18 days. Normal excitation or contraction of the skeletal muscle fibers in early age appears necessary for the microscopic pathological expression of the dystrophic gene in skeletal muscles in the UMX‐7.1 strain hamsters. These experiments constitute a rare and clear example of consistent prevention of skeletal muscle cell destruction in vivo in an inherited myopathy.
Decreased chemiluminescence in thymocytes of dystrophic hamsters
Authors: Con Andrew R. , Wrogemann Klaus
Published: January 2005

When thymocytes are stimulated they generate reactive oxygen species, which under appropriate conditions produce chemiluminescence (CL). The reactions occur near the cell surface. Since genetically determined muscular dystrophies are currently considered “membrane diseases”, we tested the CL of thymocytes from dystrophic hamsters, strain BIO 14.6, in comparison with control animals of the Rb‐strain. CL of 33 × 106 thymocytes each was monitored in a liquid scintillation counter at 32 C. Dystrophic cells stimulated with concanavalin A (Con A) reached only 60% of the normal peak CL. When stimulated with the calcium ionophore A23187, dystrophic cells exhibited only 40% of the peak CL of control cells. The thymus weight of dystrophic hamsters was significantly reduced. It is not known yet whether these alterations of the thymus are secondary to extrathymic factors or whether they are intrinsic to the thymocyte. If the latter is true, it would be an indication that the genetic defect of dystrophic hamsters is also expressed in the thymus.
A freeze‐fracture study of normal and dystrophic C57BL mouse muscle
Authors: Dulhunty Angela , Aaist Angelo Valois
Published: January 2005

Freeze‐fracture replicas of normal and dystrophic C57BL mouse muscle and kidney were examined to see whether there was a deficit in plasmalemmal particles which others suggest is a feature of dystrophies. When compared with normal membranes there was an increase in the particle density in dystrophic extensor digitorum longus muscle, a decrease in dystrophic soleus muscle, and no change in dystrophic kidney. Therefore there was not a general deficit in intramembrane particles in this dystrophic tissue. Indirect evidence supported the hypothesis that abnormalities in dystrophic mouse muscles are caused by abnormal motor input. The density of indentations, parallel to the T‐tubule, on the flat surface of the terminal cisternae can be modulated by the motor nerve. Changes were found in identation density in dystrophic muscle which were similar to changes seen after transection of the spinal cord in the mid‐thoracic region. There were parallel changes in contractile properties and identation density in dystrophic fibers.
Parenteral branched‐chain amino acid treatment and avian dystrophy
Authors: Hudecki Michael S. , Pollina Catherine M. , Heffner Reid R.
Published: January 2005

Genetically homozygous line 413 dystrophic chickens were given twice‐daily intraperitoneal injections of solutions containing branched‐chain amino acids (BCAA‐leucine, valine, isoleucine) either alone or in combination; and their α‐ketoacid analogs (α‐ketoisocaproic and α‐ketoisovaleric acids). Another trial consisted of an amino acid mixture containing BCAA. Amino acid supplementation in each case significantly prolonged righting ability measured regularly by a standardized flip‐test procedure. Enhanced functional ability was not generally accompanied by a decrease in plasma creatine kinase activity. However, a measurable increase in the affected pectoralis major muscle mass and protein content (female chickens in particular) was found with BCAA therapy. Moreover, the increase in muscle bulk was attended in some cases by a reduction in the relative number of degenerating fibers quantitated microscopically. Contrariwise, the amino acid mixture caused a reduction in pectoralis muscle mass. It is concluded that parenteral BCAA therapy offers limited benefit in retarding dystrophic symptoms in the chicken.
Changes in muscle esterases in genetically dystrophic and control littermate mice
Authors: Bianchi Roberto , Biolscid Maurizio Paro , Ghidotti Giacomo , Mussini Emilio
Published: January 2005

The hypothesis that the existence of a family of isoenzymes is at the basis of the heterogeneity of esterase activity among skeletal muscles from dystrophic Re 129J and control littermate mice was tested using isoelectrofocusing (IEF) in polyacrylamide gel. All muscles considered showed not only quantitative heterogeneity, as previously observed in this laboratory, but also qualitative differences with regard to their esterase isoenzymes. Differences in the number and the relative amounts of isoenzymatic bands were found between different muscles from both control and dystrophic animals. In most dystrophic muscles a new isoenzymatic band appeared at pH 6.6. Another band, identified at pH 5.12, was more pronounced in dystrophic than in control muscles. The specificity of these observations is indirectly supported by the fact that other tissue, such as heart, liver, and kidney, did not show the quantitative or qualitative abnormality present in the dystrophic skeletal muscles.
Translocation of the temporalis muscle for treatment of facial paralysis
Authors: White Timothy P. , Faulkner John A. , Markley John M. , Maxwell Leo C.
Published: January 2005

Our purpose was to characterize in the rhesus monkey the structure and function of vascularized temporalis muscle flaps innervated by the facial nerve after translocation into the site of the denervated zygomaticus muscle. Animals were killed at 28 to 120 days following translocation. Control data were obtained from the contralateral side. Twenty‐eight days after translocation, the time to reach peak twitch tension and one‐half relaxation time were 170% of control zygomaticus muscle. Contraction times decreased with time and reached control values by 100 days. Absolute isometric tetanic tension was not different between the flap (4.29 ± 1.28 newtons; X ± SEM) and control zygomaticus (3.95 ± 0.80 newtons). Succinate oxidase activity of the flap decreased from 279 ± 18 nl O2/mg protein/min to control zygomaticus values (98 ± 18) by 110 days. The type 1 fiber cross‐sectional area of the flap was 52% of control temporalis muscle and 150% of control zygomaticus muscle (P < 0.05). The temporalis flap demonstrated viable structure and function and appeared useful in facial movements.
Two major allelic forms of myosin light chain‐1 in strains of normal and dystrophic chickens
Authors: Rushbrook Julie Ivory , Yuan Anna I , Stracher Alfred
Published: January 2005

Evidence is presented from electrophoresis and peptide‐mapping for the existence of two major allelic forms of myosin light chain‐1 in the fast white muscle fibers of domestic chickens. One form predominates in birds of White Leghorn stock, the other in birds of New Hampshire Red stock. The two light chain‐1 forms were invariant during development. Variability was not detected in light chains‐2 or ‐3. The distribution of the two forms in two strains homozygous for the am gene for muscular dystrophy—Connecticut dystrophic and line 413—and their controls, White Leghorn and line 412, respectively, while clearly unrelated to avian dystrophy, emphasizes the heterogeneity in background genes of these non‐inbred lines and indicates caution in their use in studies of avian dystrophy.
Neuromuscular reaction to paired stimuli
Authors: Reitter Bernd F. , Johannsen Swantje
Published: January 2005

A modification of the twin pulse method is described, by which the nerve tested is stimulated at one proximal site percutaneously and the neuromuscular response to it is derived from a dependent muscle. An electronic subtraction procedure provides separation of the conditioned muscle action potential for measurement by means of a microcomputer. Several parameters were determined in the conditioned action potential and compared to the same criteria in an unconditioned single action potential. Changes of the conditioned action potential were measured at fixed stimulus intervals between 2 and 6 msec. Preliminary normal ranges interindividually and intraindividually were established. Their dependency on skin surface temperature was determined. In polyradiculoneuropathy, the data for motor nerve conduction velocity were characteristically pathologic, and neuromuscular reaction to paired stimuli data deviated minimally from normal. In vincristine neuropathy, motor nerve conduction velocity was normal, but neuromuscular reaction to paired stimuli data fell outside the normal range early in the clinical course. Since polyradiculoneuropathy is a primary demyelinating and remyelinating process and vincristine neuropathy is an example of axonal degeneration, neuromuscular reaction to paired stimuli can facilitate the differential diagnosis in polyneuropathy. Furthermore, this method seems apt to quantify axonal degeneration. In a mixed form of polyneuropathy, peroneal muscular atrophy, motor nerve conduction velocity, as well as neuromuscular reaction to paired stimuli, were abnormal, the latter resulting in abnormally high relative amplitudes. In muscle disorders such as Duchenne muscular dystrophy, neuromuscular reaction to paired stimuli data was abnormal, contrasting experiments using double stimulation of the diseased muscle itself.
Genuine myotubular myopathy
Authors: Edström Lars , Wróblewski Romuald , Mair Williamg. P.
Published: January 2005

Two patients, a father and his 14‐year‐old son, were suffering from a facioperoneal syndrome, and muscle biopsy findings were consistent with a myotubular myopathy. The father exhibited central nuclei in most muscle fibers, but his son had typical changes exclusively in hypotrophic type I fibers. The cytochemical and ultrastructural analysis revealed a spectrum of pathological changes typical of myotubular myopathy. Energy‐dispersive electron probe x‐ray microanalysis was performed on 6‐to 12‐μm thick freeze‐dried cryosections visualized in the scanning or scanning transmission mode of electron microscopy. We found a high intracellular sodium and chlorine concentration and a low potassium concentration in comparison with control muscles. These changes pointed in the direction similar to results from human fetal muscle. The changes in the intracellular elemental composition may indicate a membrane pump dysfunction, which might be caused by a partial arrest in muscle fiber maturation.
Sodium currents in human skeletal muscle fibers
Authors: Decoursey T. E. , Bryant S. H. , Lipicky R. J.
Published: January 2005

Sodium currents from human external intercostal muscle fibers were recorded using the Hille‐Campbell voltage clamp method. Sodium currents are analyzed in terms of the m and h parameters of the Hodgkin‐Huxley model. The results indicate that the kinetics and voltage dependence of sodium currents in human skeletal muscle fibers are very similar to those reported in rat fibers.
Bridging junctional processes in couplings of skeletal, cardiac, and smooth muscle
Authors: Forbes Michael S. , Sperelakis Nick
Published: January 2005

Junctional processes are found in the junctional gap of couplings in skeletal, cardiac, and vascular smooth muscle cells. Visualization of the structure of junctional processes is greatly facilitated by the use of a tilting specimen stage and stereoscopic analysis. Relatively small changes of tilt angle create a spectrum of images for the same junctional process which can range from that of an amorphous electron‐opaque body to a distinct linear structure (“pillar”). In both striated and smooth muscles, pillars connect the sarcolemma with the limiting membrane of junctional sarcoplasmic reticulum (J‐SR). In addition, in vascular smooth muscle cells, pillars join the J‐SR with surface‐connected caveolae.
Tropomyosin and troponin C from human fetal, adult, and dystrophic skeletal muscle
Authors: Romero‐Herrera Alejo E. , Lieska Norman G.
Published: January 2005

Human skeletal muscle tropomyosin and troponin C were assessed for potential changes in quantity and subunit composition during development and in Becker muscular dystrophy. The proteins were purified or separated into subunits by ion‐exchange chromatography. The fetal and dystrophic sources yielded less of these proteins than the adult and also contained additonal types of tropomyosin chains. The findings may have implications for the disease process and emphasize the feasibility of direct preparative study of human muscle.
Heterogeneity of adult human striated muscle tropomyosin
Authors: Romero‐Herrera Alejo E. , Nasser Sam , Lieska Norman G.
Published: January 2005

The amino acid sequences of the human skeletal muscle tropomyosins were elucidated. Of the three α‐types identified, the major fraction (identical to the single myocardial species) differed by 23 and 25 amino acid residues from the two minor α‐forms and by 42 residues from β‐tropomyosin. The two β‐components differed only by deletion of the C‐terminal residue in the minor fraction. These sequences will facilitate analysis of tropomyosin from developmental and diseased states.
Prolongation of post‐tetanic facilitation in infant botulism
Authors: Fakadej Alexander V. , Gutmann Ludwing
Published: January 2005

The electrophysiologic studies in a case of infant botulism show a variety of abnormalities including tetanic and post‐tetanic facilitation (PTF) of the small single evoked muscle action potential. The enlarged amplitude of the single evoked muscle action potential following a 10‐second tetanic nerve stimulation persisted up to 21 minutes. The prolongation of PTF is a unique feature of botulism.
Nuclear inclusions in oculopharyngeal muscular dystrophy
Authors: Martin Jean‐Jacques R. , Ceuterick Chantal M. , Mercelis Rudolf J.
Published: January 2005

The ultrastructural study of a skeletal muscle biopsy in a case of familial oculopharyngeal muscular dystrophy confirms the presence of 7–8 nm wide tubular filaments within muscle fiber nuclei.
In vivo administration of a thiol protease inhibitor, E‐64‐C, to hereditary dystrophic chicken
Authors: Sugita Hideo , Kimura Masaaki , Tarumoto Yasuo , Tamai Masaharu , Hanada Kazunori , Ishiura Shoichi , Nonaka Ikuya , Ohzeki Masahiro , Imahori Kazutomo
Published: January 2005

Line 413 hereditary muscular dystrophic chickens were given twice daily subcutaneous injections of 150 mg or 300 mg/kg body weight of E‐64‐c, a potent thiol protease inhibitor, from 10 days ex ovo to 89 days of age. The administration of high doses of E‐64‐c did not influence the growth curve, the course of the “flip number” the chronological changes of serum CK, PK, and LDH, and the number of the necrotic fibers and also the histogram of the fiber diameters. The activity of Ca2+‐activated neutral protease (CANP) in superficial pectoralis muscle was decreased by E‐64‐c in female chickens, but still remained higher than normal. In males, however, the CANP activity was not decreased at all. The male dystrophic chickens showed heavier body weights, lower flip number, and higher serum enzymes during the course of the experiment and higher CANP activities in superficial pectoralis muscles than females.
Study of neurotrophism in normal/dystrophic parabiotic mice
Authors: Saito Akitsugu , Law Peter K. , Fleischer Sidney
Published: January 2005

The trophic influences of nerve and muscle on one another were studied in normal and dystrophic littermates of C57BL/6J dy2J mice parabiosed at 20 to 23 days after birth. Each parabiont had a soleus muscle cross‐reinnervated by a tibial nerve of its partner. Ultrastructural abnormalities of muscle and endplate were quantified and compared 6 to 7 months postoperatively. The dystrophic nerve degenerated despite reinnervation to a normal muscle. The normal muscle did not prevent the dystrophic nerve from degenerating, and the dystrophic nerve induced degenerative changes in the reinnervated normal muscle. Normal nerve did not retard the genetically programmed degeneration of the dystrophic muscle. The dystrophic muscle, however, did not appear to cause normal nerve terminals to degenerate. We conclude that both nerve and muscle cells in dystrophic mice express characteristics of muscular dystrophy. Muscle fibers of a few motor units further suffer from abnormal neurotrophic influence because of the degeneration of the motor neurons. Myotrophic influence on nerve was not observed.
Serum creatine kinase isoenzymes: A review
Authors: Nanji Amin A.
Published: January 2005

In the last few years, several conditions giving rise to increases of the MB and BB isoenzymes of creatine kinase, and several electrophoretic variants of creatine kinase, and several electrophoretic variants of creatine kinase have been described. This review summarizes the nonmyocardial causes of increases of both CK‐MB and CK‐BB and also discusses the various electrophoretic variants.
Contraction time, histochemical type, and terminal cisternae volume of rat motor units
Authors: Kugelberg Eric , Thornell Lars‐Eric
Published: January 2005

Isometric contraction time (Tc) of 19 fast and slow rat motor units in the soleus and the tibialis anterior muscles was measured. The motor unit fibers subsequently marked by glycogen depletion were histochemically fiber typed as well as analyzed ultrastructurally with respect to volume of the sarcoplasmic reticulum terminal cisternae. The volume density of terminal cisternae (VvTC) was inversely related to Tc over the whole range of motor units, irrespective of type of muscle. The continuous variations in VvTC are concluded to match the extrinsic control of time course of contraction, and fusion frequency of the motor unit to match the frequency characteristics of the individual motoneurons. The volume density dependence of terminal cisternae function would result in an indirect coupling between amount and rate of calcium release and rate of calcium recaptured. VvTC and Tc were the same for some tibialis anterior and soleus motor units in spite of the different types of myosin, indicating that the type 1 and type 2 myosins have specific structural differences in fast as compared with slow muscles.
Axonal transport in neuropathy
Authors: Jakobsen Johannes , Brimijoin Stephen , Sidenius Per
Published: January 2005

Recent studies on the distribution of labeled endogenous proteins in the experimental neuropathies induced by streoptozotocin diabetes, galactose feeding, zinc pyridinethione, 2,5‐hexanedione, acrylamide, and p‐bromophenylacetylurea (BPAU) have demonstrated an impaired build up of retrogradely transported material derived from the more distal parts of peripheral nerve. In BPAU neuropathy the transport abnormality is strongly related to the degree of muscle weakness; following treatment with acrylamide the extent of the impairment is dose related. In both toxic conditions the transport abnormality is present well in advance of the first clinical signs of neuropathy. We therefore suggest that changes in retrograde axonal transport play an initial and important role in the development of many axonopathies.
Nonviral intranuclear inclusions in a nerve biopsy: An ultrastructural study
Authors: Vallat J. M. , Leboutet M. J. , Loubet A. , Corvisier N. , Dumas M.
Published: January 2005

During the ultrastructural study of a nerve biopsy from a diabetic patient suffering from chronic polyradiculoneuritis, we observed that a significant number of endoneural fibroblasts had abnormal nuclei. They contained a round, centrally located inclusion consisting of numerous irregularly arranged filaments approximately 15 nm in diameter. No such lesion in peripheral nerve has previously been reported. Interpretation of these abnormalities is difficult.
Treatment of “permanent” muscle weakness in familial hypokalemic periodic paralysis
Authors: Dalakas Marinos C. , Engel W. King
Published: January 2005

Three patients with Hypokalemic Periodic Paralysis (HOPP)‐associated progressive interattack muscle weakness, who became unresponsive or worsened by acetazolamide, responded favorably to dichloro‐phenamide, a more potent carbonic anhydrase inhibitor. Dichloro‐phenamide in single‐blind placebo‐controlled trials, considerably improved functional strength in two of the patients and had a moderate but definite effect in the third. Muscle groups graded 4/5 (MRC scale) returned to normal; very weak (0–3/5) atrophic muscles, improved to a minor degree. In one patient with acetazolamide‐resistant paralytic attacks, dichlorophenamide also diminished the frequency and severity of the acute attacks. Dichlorophenamide had, in the present study, less effect than acetazolamide in reducing serum HCO and elevating Cl−. Its effectiveness may be related to the degree of sensitivity of certain HOPP patients to alterations of Cl− and/or HCO serum levels or to a different action of the drug unrelated to carbonic anhydrase inhibition or acidosis. Dichlorophenamide should be considered as an alternate to acetazolamide in the treatment of patients with HOPP‐associated interattack muscle weakness who have become unresponsive or worsened by acetazolamide.
Hypoxanthine and McArdle disease: A clue to metabolic stress in the working forearm
Authors: Brooke Michael H. , Patterson Victor H. , Kaiser Kenneth K.
Published: January 2005

Forearm exercise in a patient with myophosphorylase deficiency resulted in abnormally high levels of hypoxanthine in the venous blood. The post‐exercise hypoxanthine response may reflect ATP depletion in the muscle and provides a useful screening test in muscle diseases with abnormal energy metabolism.
Prolonged electromechanical coupling time intervals in skeletal muscle of pigs susceptible to malignant hyperthermia
Authors: Nelson Thomas E. , Flewellen Eugene H. , Arnett David W.
Published: January 2005

Electromechanical properties of skeletal muscle were compared between malignant hyperthermia (MH)‐susceptible and control pigs. These muscle properties were studied both in vivo and in vitro. The in vivo time interval from nerve stimulation to onset of mechanical tension was longer in muscle of pigs susceptible to MH. Kinetics of formation of the in vivo compound muscle action potential did not differ between pig groups, whereas the time from peak of the muscle action potential to tension onset was longer for MH muscle. In vitro the time from direct stimulation to tension onset was also longer for MH muscle. These results suggest that the mechanism causing longer electromechanical time intervals in MH skeletal muscle is distal to the myoneural junction. Data comparing contraction kinetics between muscle from MH and control pigs indicates that the mechanism contributing to the longer time interval involves the transfer of signal from the transverse tubule to the sarcoplasmic reticulum in the pigs studied.
Effects of graded duration of stretch on normal and dystrophic skeletal muscle
Authors: Frankeny John R. , Holly Robert G. , Ashmore C. Robert
Published: January 2005

Daily passive stretch for six weeks ranging from 30 minutes to 24 hours per day was studied in the patagialis (PAT) muscle of normal and dystrophic chickens. Significant increases in wet weight, cross‐sectional area, and mean fiber cross‐sectional area occurred in both normal and dystrophic PAT in response to stretch of all daily durations tested. More than 50% of the growth occurring in response to continuous stretch was elicited by as little as 30 minutes of stretch per day. Oxidative enzyme capacity increased proportionately with increasing durations of stretch in the normal PAT. Similarly, increasing duration of stretch progressively retarded the onset of histopathological signs in the dystrophic PAT. We conclude that daily stretching for as little as 30 minutes per day is a powerful inducer of growth in normal and dystrophic muscle and that the progress of the histopathology in dystrophic muscle is delayed in proportion to the daily duration of stretch.
A benign form of reducing body myopathy
Authors: Oh Shin J. , Meyers Gary J. , Wilson Edward R. , Alexander C. Bruce
Published: January 2005

A 4‐year‐old boy with nonprogressive myopathy since 2 years of age had “reducing bodies” in muscle biopsy specimens. Clinical and morphological findings are presented, which support the existence of a benign form of reducing body myopathy.
The electrodiagnostic findings in peripheral neuropathy associated with monoclonal gammopathy
Authors: Kelly John J.
Published: January 2005

The electrodiagnostic findings in 51 patients with monoclonal serum proteins of different etiologies and peripheral neuropathies are analyzed and the findings in an additional 10 patients with multiple myeloma are discussed. The nine patients with monoclonal gammopathy of undetermined significance had electrodiagnostic patterns consistent with either predominant axonal degeneration or demyelination. Almost all 15 patients with osteosclerotic myeloma had evidence of a demyelinating neuropathy. The 27 patients with primary systemic amyloidosis almost always displayed evidence of an axonal neuropathy with superimposed carpal tunnel syndrome in some cases. The 10 patients with multiple myeloma had heterogeneous findings. Electrodiagnostic studies can aid in classifying these patients and suggest the likelihood of a specific etiology.
Age‐related differences in absolute numbers of skeletal muscle satellite cells
Authors: Gibson Marcia C. , Schultz Edward
Published: January 2005

The absolute number of satellite cells (SC) in young and adult rat skeletal muscle was estimated by correlating data from light and electron microscopic quantitation of myofiber nuclei (myonuclei and satellite cell nuclei) with biochemical assays for determining total muscle DNA content. Expressed both as a proportion of total myofiber nuclei and as absolute numbers, satellite cells are more numerous in the predominantly oxidative soleus muscle than in the mixed glycolytic/oxidative extensor digitorum longus (EDL) muscle at 1, 12, and 24 months of age. Satellite cell proportions decline gradually in both muscles with advancing age, but absolute numbers increase significantly in the soleus between 1 and 12 months, while EDL exhibits a continuous significant decline in satellite cells between each of the ages examined.
Distribution of different fiber types in human skeletal muscles: Effects of aging studied in whole muscle cross sections
Authors: Lexell Jan , Henriksson‐Larsén Karin , Winblad Bengt , Sjöström Michael
Published: January 2005

The effects of aging on the total number and size of fibers, and the proportion and distribution of type 1 (slow twitch) and type 2 (fast twitch) fibers were studied in cross sections (15 μ thick) of autopsied whole m. vastus lateralis from two age groups. Each group consisted of six, previously physically healthy males (mean age 72 ± 1 years and 30 ± 6 years, respectively). The size of the muscles of the older individuals was 18% smaller (P < 0.01) and the total number of fibers was 25% lower (P < 0.01) than those of the young individuals (mean number 364,000 ± 50,000 vs 478,000 ± 56,000). There was, however, no significant difference in the mean fiber size (indirectly determined) orthe proportion of the two fiber types, though a preferential reduction in type 2 fiber number in the aged individuals was seen. The relative occurrence of the fiber types at various depths in the aged muscles was found to be more even than in muscles from the young individuals. The results suggest that the aging atrophy in m. vastus lateralis, at least up to the age of 70, is primarily the result of a loss of fibers.
Quantitation of metabolites in human skeletal muscle during rest and exercise: A comparison of methods
Authors: Sabina Richard L. , Swain Judith L. , Bradley Walter G. , Holmes Edward W.
Published: January 2005

Quantitation of muscle metabolites in vastus lateralis needle biopsies from human subjects at rest and following exercise is evaluated using three different methods of normalization of the data, i.e., total protein, total creatine, and NAD+. Coefficients of variation between patient analyses are similar when the metabolite data are normalized by any of the descriptors in resting muscle and in muscle samples obtained following vigorous exercise. When multiple samples are taken from individual patients the intrapatient coefficient of variation is less than that for interpatient comparisons. Normalization to total creatine or NAD+ yields significantly smaller coefficients of variation than does normalization to total protein in these intrapatient comparisons (P < 0.05). Based on these comparisons, we conclude that any of these methods evaluated for normalizing metabolite content is adequate for studying human subjects, but the total creatine and NAD+ methods may offer some advantage because of the lower variability obtained with these analyses.
Effects of acrylamide and some other sulfhydryl reagents on spontaneous and pathologically induced terminal sprouting from motor end‐plates
Authors: Kemplay Sheila , Cavanagh John B.
Published: January 2005

The innervation of the normal rat sternocostalis muscle exhibits a constant low level of short spontaneous terminal sprouts visible in zinc iodide‐osmium (ZIO) and in methylene blue‐stained preparations. Acrylamide inhibits these spontaneous sprouts in a dose‐dependent manner. This inhibition is mimicked by N‐ethylmaleimide (a sulfhydryl group blocking agent) and can be nullified when acrylamide is given after the sulfhydryl group protecting agent, dithiothreitol (DTT). This could not be reversed by giving DTT 3 hours after acrylamide. Further more when given alone DTT increases the level of spontaneous terminal sprouting seen in ZIO and in methylene blue‐stained preparations. These findings suggest that the binding of acrylamide to sulfhydryl groups is involved in the inhibitory process. Acrylamide also reduces the number and length of the reactionary terminal sprouts, seen in ZIO and in methylene blue‐stained preparations, that follow partial denervation or local injection of botulinum toxin. These inhibitory effects are long‐lasting; recovery still has not fully occurred 4 weeks after a single dose of acrylamide (50 mg/kg). The roles of glutathione and other sulfhydryl components of axons are discussed in relation to the mechanism of acrylamide neurotoxicity.
Neurons induce contractions in myotubes containing only muscular dysgenic nuclei
Authors: Powell Jeanne A. , Peterson Alan , Paul Carol V.
Published: January 2005

Muscular dysgenic (mdg/mdg) myotubes cultured alone do not contract. Glucosephosphate isomerase (GPI‐1) isozymes were analyzed to determine the final genotype of cultured dysgenic (mdg/mdg, gpi‐1a/a) myotubes to which normal embryonic spinal cord and limb cells (CBA/J +/+, gpi‐1b/b) had been added. Although both myoblast and spinal cord cell additions caused induction of spontaneous contractions, only myoblasts fused with the myotubes to create functional heterokaryons. Spinal cord cells did not fuse with dysgenic myotubes, but formed functional synapses.
The treatment of scoliosis in duchenne muscular dystrophy
Authors: Rideau Y. , Glorion B. , Delaubier A. , Tarlé O. , Bach J.
Published: January 2005

There are not, as yet, clear indications for the surgical management of scoliosis in Duchenne muscular dystrophy (DMD), taking into account the varying severity of the clinical course. Monitoring the vital capacity can be most important for the indication and timing of surgery. In some cases, delaying surgical intervention with conservative management using spinal braces and wheelchair inserts can permit the restrictive lung syndrome to advance to the point that surgery will be contraidicated. Ten such patients conservatively treated for an average of 5 years exhibited perhaps a slower progression but ultimately an advanced deformity. From a second group of five carefully selected and surgically treated patients, indications for spinal surgery were reviewed. Surgical intervention should be prophylatically undertaken when there is high risk of a rapidly evolving curve with a severe restrictive lung syndrome.