摘要:

AbstractA treatment has been developed to alleviate muscle weakness in murine dystrophy. Cultured myoblasts from genetically normal mouse embryos were injected into the right soleus of 20‐day‐old normal or dystrophic mice. Hosts and donors were immunocompatible but exhibited different genotype markers. Donor cells produced GPI‐1CC. Host cells produced GPI‐1BB. When compared with contralateral controls 6 months postoperatively, test dystrophic solei exhibited greater cross‐sectional area, total fiber number, wet weight, and twitch and tetanus tensions. They contained more normal‐appearing and less abnormal‐appearing fibers. Their mean fiber resting potential was similar to that of normal controls. Presence of GPI‐1CC with or without the hybrid isozyme GPI‐IBC in these mucles implied the survival and development of donor myoblasts into normal myofibers, and fusion of normal myoblasts with dystrophic satellite cells to form genetically mosaic myofibers. Injection of fibroblasts instead of myoblasts caused de

ISSN:0148-639X    

DOI:10.1002/mus.880110602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe measurement of neuromuscular jitter in single fiber electromyography may be artifactually raised by a component of interdischarge interval (IDI)‐dependent jitter caused by the velocity recovery function (VRF) in muscle fibers. We have developed a computer algorithm for on‐line mathematical correction for this artifact, thus improving the reliability of neuromuscular jitter estimates. The method, based on a modeling technique, was validated using intramuscular stimulation in order to either exclude an IDI‐dependent component (using regular stimulation) or to include an IDI‐dependent component (using pseudorandom stimulation). In 10 normal subjects the distribution of 106 corrected jitter values obtained using voluntary activity showed no difference from the measured values. This finding implies that previously published values for normal jitter are not likely to have been influenced by the VRF

ISSN:0148-639X    

DOI:10.1002/mus.880110603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn recent years, injection of pure glycerol into the trigeminal cistern has been used for the treatment of trigeminal neuralgia. The mechanism of action of this therapy remains unclear. Using both light and electron microscopy, we investigated the effects of microinjections of sterile, pure glycerol into the endoneurium of the sciatic nerve of the rat. We observed total destruction of both myelinated and unmyelinated fibers. In nearly all animals, signs of automutilation were observed in the paralyzed limb. Histological evidence of nerve degeneration appeared soon after injection, with intense proliferation of perineurial cells that eventually divided the endoneurium into numerous microcompartments.

ISSN:0148-639X    

DOI:10.1002/mus.880110604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractFourth finger stimulation has been used to obtain the compound nerve action potential (CNAP) of the median and ulnar nerves by a single cutaneous bipolar recording electrode placed in some specific sites of the upper limb. In normal subjects, the response was a combination of both action potentials which could be seen as separated peaks only when the recording was made at midarm with the elbow flexed at 90°. This finding is mainly attributed to the longitudinal sliding of nerves according to the joint movements. In patients with a carpal tunnel syndrome, there were a striking separation between the responses of both nerves in wrist recording. This finding allows this technique to be applied in the clinical inspection of median nerve entrapment at wrist, demonstrating graphically the delay on the median nerve action potential with regard to that of the ulnar nerve

ISSN:0148-639X    

DOI:10.1002/mus.880110605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractWe examined the site of androgen action in maintaining the sexually dimorphic spinal nucleus of the bulbocavernosus (SNB) and its target perineal muscles, the bulbocavernosus (BC) and levator ani (LA), in rats. To determine whether androgen action on SNB motoneurons is crucial for BC/LA survival, we removed SNB cells in newborn female rats by lumbosacral spinalectomy, administered testosterone propionate (TP) on days 1 and 3 of life, and examined for the presence of BC/LA muscles in adulthood. BC/LA muscles were present in all TP‐treated spinalectomized females, and staining of these muscles with alpha‐bungarotoxin or for acetylcholinesterase showed no evidence of cholinergic innervation. Thus, complete neonatal denervation of the BC/LA does not prevent TP from sparing these muscles, suggesting that androgen acts directly upon BC/LA muscles to maintain them during development. This androgenic maintenance of the BC/LA may be crucial for the survival of SNB motoneur

ISSN:0148-639X    

DOI:10.1002/mus.880110606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe Ca ATPase content in the sarcoplasmic reticulum (SR) of fast and slow twitch skeletal fibers was estimated using two well‐characterized muscles of the guinea pig: the white bundle of the vastus lateralis and the soleus. Ca ATPase surface density was determined by counting the projections of individual molecules revealed on the cytoplasmic surface of freeze‐dried, rotary‐shadowed microsomal vesicles isolated from the two muscles. The Ca ATPase densities were 32,000/μm2and 25,000/μm2for the vastus lateralis and soleus muscles, respectively. The percentage of membrane area occupied by Ca ATPase‐free lipid patches was estimated using freeze‐fractured, rotary‐shadowed in situ SR. In soleus muscle the free SR of terminal cisternae and the longitudinal SR have 34.5 and 19.7% of their surface free of ATPase, respectively. In the white vastus less than 1% of the surface was not occupied by Ca ATPase. These values were combined with stereological data from the literature to give a ratio of total Ca ATPase content per unit fiber volume of 1:2, slow versus fast. This is considerably less than the approximately sixfold difference in the overall relaxation time and the half times to relaxation between the two fiber types. This suggests that other factors such as differences in enzyme kinetics or cytoplasmic Ca buffering proteins must also play a role in determining rate

ISSN:0148-639X    

DOI:10.1002/mus.880110607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractTwenty patients with thoracic outlet syndrome (TOS) seen at the Mayo Clinic between October 1984 and November 1985 were studied prospectively with routine nerve conduction studies, concentric needle examination, and bilateral median and ulnar somatosensory evoked potentials (SEPs). Results of nerve conduction studies and needle examination were abnormal in 30% of the patients, one patient having a reduced ulnar sensory nerve action potential amplitude and five others having neurogenic motor unit potential changes in the hand muscles. Ulnar SEPs were abnormal in three patients (15%), and median SEPs were abnormal in one patient, who also had abnormalities in ulnar SEPs. In patients with TOS, routine nerve conduction studies and needle examination were the most helpful electrophysiologic studies in excluding more common conditions. The routine use of ulnar SEPs in the evaluation of patients with TOS is probably not worth‐whil

ISSN:0148-639X    

DOI:10.1002/mus.880110608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe myotonia‐inducing effects of furosemide and clofibrate, two widely used pharmaceutical agents, were investigated in excised human external intercostal muscle. The effects of anthracene‐9‐carboxylic acid (9‐AC), a well‐known myotonia‐producing chemical, were also tested for comparison. In the presence of these drugs the electrical threshold was lowered, and a constant current pulse produced multiple spiking. Short trains of direct stimuli were often followed by after‐activity, and this caused a myotonia‐like prolongation of muscle contraction. Voltage‐clamp experiments showed that 0.05 mManthracene‐9‐carboxylic acid, 1 mMfurosemide, and 1 mMclofibrate decreased the chloride conductance of the muscle fiber membrane to 14, 18, and 40%, respectively, of the normal value, and the myotonia‐inducing potency of the 3 drugs was correlated with the decreased chloride conductance. The potassium currents were not affe

ISSN:0148-639X    

DOI:10.1002/mus.880110609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractResistance to ischemic conduction block (RICB) was studied in rats with streptozotocin (STZ) induced hyperglycemia, hyperglycemia by glucose injection, and glycerin‐induced hyperosmolarity. Ischemia was produced by tight ligation at the base of the tail. The time required for nerve action potentials (NAP) to disappear was defined as the disappearance time of NAP (DT‐NAP). Both STZ and glucose rats showed a marked prolongation of DT‐NAP at 2 hours after injection of STZ (up to 120 minutes) or glucose (up to 95 minutes), as compared with the control rats (less than 45 minutes). Hyperosmolar rats showed no prolongation of DT‐NAP. The amplitude of NAP remained at the initial level for at least 2 hours after ligation of the sciatic nerve, whereas NAP disappeared within 45 minutes after ligation of the abdominal aorta. These findings indicate that the RICB can be produced by means of hyperglycemia without the presence of diabetic neuropathy and is the most sensitive indicator of hyperg

ISSN:0148-639X    

DOI:10.1002/mus.880110610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractRegenerated myofibers formed subsequent to orthotopic transplantation of young, dystrophic mouse muscle fail to display the extensive histopathological changes characteristics of murine dystrophy.3In order to determine whether this modification of the phenotypic expression of murine dystrophy is unique to the transplantation system or whether it can be found when other extreme trauma induces dystrophic muscle to regenerate, the extensor digitorum longus muscles of 4–6‐week‐old normal (129 ReJ +/+) and dystrophic (129 ReJdy/dy) mice were given two series of injections of the myctoxin bupivacaine, spaced 12 hours apart. These injections resulted in necrosis of ∼90% of the original myofibers. At 100 days after injection, the regenerated normal muscle appeared “healthy,” whereas the regenerated dystrophic muscle displayed histopathological changes. It is suggested that the differences in the time course of innervation of the myotubes in the transplantation system as compared with that in the bupivacaine system may be a factor in determining whether regenerated dystrophic myofibers express a dystrophic

ISSN:0148-639X    

DOI:10.1002/mus.880110611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY