bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical and immunocytochemical analysis in chronic proximal spinal muscular atrophy
Authors: Hamida Christiane Ben , Soussi‐Yanicostas Nadia , Butler‐Browne Gillian S. , Bejaoui Khemissa , Hentati Fayçal , Hamida Mongi Ben
Published: January 2005

Immunocytochemical and biochemical analyses were carried out on patients affected by chronic SMA. Three groups of patients were identified. In group I, the muscle presented a fascicular atrophy; a high percentage of atrophic type II fibers; and fibers expressing fast, slow, embryonic, and fetal myosin isoforms. In group II, the muscle was characterized by atrophic fibers and normal/hypertrophic fibers expressing only slow myosin isoforms. In group III, the muscle was characterized by fiber type grouping and fibers coexpressing fast and slow myosin isoforms but never embryonic or fetal MHC isoforms. The muscles of groups I and III contained both fast and slow myosins whereas group II muscles were predominantly slow by immunocytochemical analysis or only slow by biochemical analysis. In view of these results, immunocytochemical and histochemical analyses could help to classify chronic SMA and help to understand the different pathogenic processes which seem to be related to the maturational stage of the muscle at the age of onset of the disease. © 1994 John Wiley & Sons, Inc.
Sympathetic skin response and R–R interval variation in chronic uremic patients
Authors: Wang Shuu‐Jiun , Liao Kwong‐Kum , Liou Hung‐Hsiang , Lee Shei‐Shee , Tsai Ching‐Piao , Lin Kon‐Ping , Kao Ko‐Pei , Wu Zin‐An
Published: January 2005

Sympathetic skin response (SSR) and R–R interval variation (RRIV) were studied in 36 chronic, nondiabetic uremics to compare with their nerve conduction studies (NCS) and clinical dysautonomia. Abnormal SSR was noted in 5 (13.9%) patients, abnormal RRIV in 14 (38.9%), and abnormal NCS in 26 (72.2%). The patients were classified into three groups: group (GP) 1: “normal,” n = 21 (58.3%), normal RRIV and SSR; GP 2: “isolated parasympathetic dysfunction,” n = 10 (27.8%), abnormal RRIV and normal SSR; and GP 3: “sympathetic sudomotor dysfunction,” n = 5 (13.9%), abnormal SSR. A significant difference in age was found among the three groups (GP 3 > GP 2 > GP 1; P < 0.0001, ANOVA). After controlling the age factor, we still noted a tendency toward increasing NCS disturbances (distal latency and nerve conduction velocity of peroneal nerve; P < 0.05, multiple regression analysis) and frequencies of clinical autonomic symptoms (postural dizziness and impotence; P < 0.05, Mantel–Hanszel test) from GP 1 to GP 3. Patients with abnormal SSR (GP 3) displayed significantly higher frequencies of postural dizziness and impotence, indicating the relationship between an absence of SSR and clinical dysautonomia. © 1994 John Wiley & Sons, Inc.
Anionic phospholipids calcium binding sites in Duchenne and murine X‐linked muscular dystrophy
Authors: Moggio Maurizio , Prelle Alessandro , Fagiolari Gigliola , Checcarelli Nicoletta , Sciacco Monica , Ciscato Patrizia , Scarlato Guglielmo
Published: January 2005

Duchenne muscular dystrophy (DMD) and murine X‐linked muscular dystrophy (mdx) are genetically homologous and both characterized by absence of dystrophin. The function of this protein is not defined nor is the pathogenesis of the severe muscle necrosis and progressive weakness found in DMD but not in mdx. Recently we found that anionic phospholipid (AP) calcium binding sites are lacking at the muscle cell surface in DMD and we correlated these data with dystrophin deficiency and muscle necrosis. In order to verify the role of AP lack in the pathogenesis of muscle necrosis in DMD we studied the ultrastructural localization of these Ca++ receptors in mdx muscle membrane showing that they are normally represented as they are in control mouse and normal human muscle. The absence of AP in DMD compared with a normal distribution in mdx suggests that these calcium binding site alterations play an important and specific role in muscle fiber necrosis. © 1994 John & Sons, Inc.
EMG changes in respiratory and skeletal muscles during isometric contraction under normoxic, hypoxemic, or ischemic conditions
Authors: Badier Monique , Guillot Chantal , Lagier‐Tessonnier Francoise , Jammes Yves
Published: January 2005

The consequences of general hypoxemia (PaO2 = 51 mmHg) on two muscle groups (adductor pollicis and diaphragm) sustaining 80% maximal isometric voluntary contraction were studied in healthy individuals. For adductor pollicis, contractions were also executed after 10−s or 3−min rest ischemia. Compared to control, i.e., normoxic, sustained isometric workloads, significant shortening of endurance time occurred only when adductor pollicis contracted under hypoxemic conditions. In both muscle groups, a 3‐min ischemia test as well as hypoxemia reduced the rate of changes in integrated surface EMG in a low frequency band and lowered, or did not modify, the rate of change in the high above low frequency ratio. Recovery of normal patterns of EMG changes was prolonged only after the adductor pollicis contracted under hypoxemic conditions. The present data show that both hypoxemia and prolonged rest ischemia reduced the rate of changes in quantitative EMG activity, with the more significant effects being measured under hypoxemia. © 1994 John & Sons, Inc.
Variable effect of calcium channel blockers on the decremental response in experimental autoimmune myasthenia gravis
Authors: Wirguin Itzhak , Brenner Talma , Sicsic Camille , Argov Zohar
Published: January 2005

We tested the effect of intravenous administration of verapamil and nimodipine on the decremental response in rabbits with experimental autoimmune myasthenia. Nimodipine produced an immediate augmentation of the decremental response to 3‐Hz nerve stimulation, which lasted about 30 min. In contrast, verapamil caused marked amelioration of the decrement beginning 30 min after injection. Our findings are consistent with previous reports suggesting that verapamil has a presynaptic effect of enhanced acetylcholine release at the neuromuscular junction. Since evaluation of a drug effect in vivo in animals with experimental autoimmune myasthenia gravis may be more pertinent to its effect on patients with myasthenia gravis (MG), verapamil might prove to be safer in MG than nimodipine. However, due to the additional effects of calcium channel blockers, the safety of their use in myasthenia gravis cannot be inferred from the experimental results. © 1994 John & Sons, Inc.
Voluntary contraction and responses to submaximal cervical nerve root stimulation
Authors: Shafiq Ruxsana , Macdonell Richard
Published: January 2005

Voluntary contraction of hand muscles increases compound muscle action potential (CMAP) amplitudes evoked by submaximal electrical percutaneous cervical stimulation (EPCS). This has been reported to be due to an intraspinal, presynaptic mechanism. We studied the effects of voluntary contraction on hypothenar CMAP amplitudes in 5 volunteers following electrical peripheral nerve stimulation at the wrist, EPCS, magnetic stimulation at the neck and the effects of a conditioning subthreshold cortical magnetic stimulus on CMAPs evoked by EPCS at rest. CMAP amplitudes increased with voluntary contraction of the target muscle, regardless of type or location of stimulus (P < 0.001). No increase in CMAP amplitude occurred when a conditioning transcranial stimulus was employed with EPCS (P = 0.35). Our findings indicate a peripheral rather than central mechanism underlies this effect of voluntary contraction. It is probably related to the recruitment order of motor axons, comparing voluntary activation with electrical or magnetic stimulation. © 1994 John Wiley & Sons, Inc.
Does forearm mixed nerve conduction velocity reflect retrograde changes in carpal tunnel syndrome?
Authors: Hansson Sture
Published: January 2005

The mixed nerve conduction velocity of the median nerve in the forearm diverged from the motor and sensory nerve conduction velocities and correlated poorly with the severity of carpal tunnel syndrome (CTS) in 61 hands. In contrast, the motor and sensory nerve conduction velocities in the forearm correlated well with CTS severity. The mixed nerve conduction velocity in the forearm is probably determined by nonlesioned fibers such as those from the cutaneous palmar branch of the median nerve. The motor and sensory, but not the mixed nerve conduction velocities in the forearm may be used to estimate possible retrograde impairment in CTS. © 1994 John Wiley & Sons, Inc.
Resetting of essential tremor and postural tremor in Parkinson's disease with transcranial magnetic stimulation
Authors: Pascual‐Leone A. , Valls‐Solé J. , Toro C. , Wassermann E. M. , Hallett M.
Published: January 2005

We studied the effects of transcranial motor cortex stimulation on the electromyographic characteristics of tremor in 9 patients with familial essential tremor and in 12 patients with postural tremor associated with Parkinson's disease. Transcranial magnetic stimulation reset both types of tremor equally. The resetting depended on the stimulus intensity, but was most closely correlated with the duration of the electromyographic silent period that followed the stimulus‐induced motor evoked potential. Tremor resetting was present bilaterally even after focal, unilateral stimulation. Transcranial electrical stimulation failed to reset the tremor in either patient group. These results emphasize the role of central, intracortical structures in the generation of essential tremor and postural tremor in Parkinson's disease. © 1994 John Wiley & Sons, Inc.
Potassium and caffeine contractures of mouse muscles before and after fatiguing stimulation
Authors: Pagala Murali , Ravindran Kadirimangalam , Amaladevi Bellamakonda , Namba Tatsuji , Grob David
Published: January 2005

To assess the impairment of muscle membrane excitation, excitation–contraction (E–C) coupling, and contractility during muscle fatigue, we monitored the contracture responses of resting and fatigued muscles on exposure to high potassium and caffeine. On exposure to 140 mmol/L potassium, mouse extensor digitorum longus (EDL) developed a contracture which was 15.7% of tetanic tension before fatigue and 31.7% after fatigue, while soleus developed 59.4% contracture before and 68.8% after fatigue. Potassium causes contractures by depolarizing the muscle fiber membrane. Hence, membrane excitation is reduced in fatigued EDL and soleus. On exposure to 32 mmol/L caffeine, the contracture was 7.1% in resting EDL, 8.5% in fatigued EDL, 50.1% in resting soleus, and 43.7% in fatigued soleus. On exposure to 1 mmol/L caffeine followed by rapid cooling, the contracture was 3.0% in resting EDL, 3.2% in fatigued EDL, 21.5% in resting soleus, and 10.3% in fatigued soleus. Caffeine causes contracture by releasing Ca+ + from the sarcoplasmic reticulum. Our results indicate reduced E–C coupling attributable to reduced membrane excitation in fatigued EDL, and reduced contractility in fatigued soleus. © 1994 John Wiley & Sons, Inc.
Prejunctional regulatory actions of androgens on a hormone sensitive muscle
Authors: Yamamoto Lücia Akie , Lapa Antonio José , Souccar Caden
Published: January 2005

The influence of androgens and time course of effects induced by hormone deprivation were examined on the spontaneous transmitter re‐ lease in the levator ani (LA) muscle of 30–180‐day‐old male rats. The resting membrane potential (RMP) and miniature endplate potentials (mepps) were recorded intracellularly from LA muscle fibers of intact animals or gonadectomized at different ages. In intact animals, the frequency of mepps increased proportionately to the muscle fiber growth up to 60 days, stabilizing thereafter. Gonadectomy at any age did not affect the RMP, but increased the frequency of mepps by 65% to 140%. The effect was detected after 15 days and was unrelated to the degree of muscle atrophy. Independently of the age of gonadectomy control values of mepp frequency were restored after 90 days, while the accompanying postjunctional changes persisted. These results indicate that androgens exert a prejunctional inhibitory influence on the spontaneous transmitter release in the rat LA muscle. The transient nature of the prejunctional effect induced by hormone deprivation indicates an adjustment of nerve terminals to persistent postjunctional alterations. © 1994 John Wiley & Sons, Inc.
Ekbom's syndrome: Lipomas, ataxia, and neuropathy with MERRF
Authors: Calabresi Peter A. , Silvestri Gabriella , DiMauro Salvatore , Griggs Robert C.
Published: January 2005

A 66‐year‐old woman with hereditary deafness and multiple symmetric lipomas presented with ataxia, slight myopathy, and neuropathy. Molecular genetic analysis of mitochondrial DNA revealed the adenine to guanine transition at position 8344 in the tRNA gene for lysine that has been associated with the myoclonic epilepsy and ragged red fiber (MERRF) syndrome. The deafness was transmitted by the patien's father and may have been an unrelated autosomal defect rather than a paternally transmitted mitochondrial point mutation. © 1994 John Wiley & Sons, Inc.
Intestinal pseudo‐obstruction in adult spinal muscular atrophy
Authors: Ionasescu Victor , Christensen James , Hart Michael
Published: January 2005

A 42‐Year‐old woman sith negative family history had the insidious onset of weakness in her lower extremities 8 years before, in 1983. The disorder slowly progressed to include cramps and muscle twitches. The diagnosis of adult spinal muscular atrophy (SMA) was made when electromyography showed large rapidly firing motor unit potentials, positive waves, and fibrillation potentials, and when muscle biopsy of the quadriceps revealed severe alterations consistent with neurogenic atrophy. The patient also had severe chronic constipation for many years. More recently she had developed unremitting diarrhea. Gastrointestinal studies showed no evidence of peristaltic contractions in the rectum, delayed gastric emptying, and abnormal jejunal manometry with altered propagation of the migrating myoelectrical complex. © 1994 John Wiley & Sons, Inc.
Repetitive nerve stimulation studies in the Lambert–Eaton myasthenic syndrome
Authors: Tim Richard W. , Sanders Donald B.
Published: January 2005

We compared changes in amplitude and area of surface recorded compound motor action potentials (CMAPs) during 20‐Hz repetitive nerve stimulation and after maximum voluntary contraction in patients with the Lambert–Eaton myasthenic syndrome (LEMS), myasthenia gravis (MG), and normal controls. There was greater potentiation of CMAP amplitude after voluntary contraction than during 20‐Hz stimulation in 10 of 14 LEMS patients; CMAP area increased more after exercise than during 20‐Hz stimulation in all LEMS patients. Although abnormal potentiation of CMAP area and amplitude was seen in equal numbers of LEMS patients, more LEMS patients demonstrated a greater than 100% potentiation of CMAP area than of CMAP amplitude. We conclude that maximum voluntary contraction is preferable to brief 20‐Hz RNS to demonstrate potentiation in LEMS because it is at least as sensitive and is less painful. Measurement of CMAP area in LEMS patients is not better than measuring the change in CMAP amplitude in demonstrating abnormal potentiation. Testing of a single hand muscle for potentiation in LEMS does not demonstrate abnormal potentiation in all LEMS patients. © 1994 John Wiley & Sons, Inc.
Ion channels in a skeletal muscle cell line from a Duchenne muscular dystrophy patient
Authors: Caviedes Raul , Caviedes Pablo , Liberona Jose L. , Jaimovich Enrique
Published: January 2005

A cell Iine (RCDMD), derived from a muscle biopsy taken from a 7‐yearold patient with Duchenne muscular dystrophy (DMD), was established in vitro using conditioned media from the UCHT1 thyroid cell line as described elsewhere (Biochim Biophys Acta 1992;1134:247–255). Unlike other cell lines established by the same procedure, RCDMD cells were highly refractory to transformation and the resulting cell line grew slowly with a doubling time of approximately 72 h. Further, cells continue to grow after more than 20 doublings and 15 passages. Some of the characteristics of the cell line include lack of reaction with antidystrophin antibodies and the presence of receptors for the dihydropyridine PN200‐110 (Kd) = 0.3 ± 0.05 nmol/L and Bmax = 1.06 ± 0.03 pmol/mg protein and for α‐bungarotoxin (Kd = 1.02 ± 0.17 nmol/L and Bmax = 4.2 ± 0.37 pmol/mg protein). Patch clamped cells in the voltage clamp configuration lack ion currents when growing in complete medium with high serum, but they can be induced to differentiate by serum deprivation and addition of hormones and trace elements. After 5 days in differentiating medium, noninactivating, delayed rectifier potassium currents are seen. At day 12, A‐type, inactivating potassium currents as well as transient inward currents are seen. In conditions in which sodium and potassium currents are absent, a very fast activating and fast inactivating calcium current was evident. The cell line offers the possibility of studying cellular mechanisms in the pathophysoplogy of DMD. © 1994 John Wiley & Sons, Inc.
Influence of recording site on CMAP amplitude and on its variation over a length of nerve
Authors: van Dijk J. Gert , van der Kamp Wim , van Hilten Bob J. , van Someren Paul
Published: January 2005

The distinctions between blocking, abnormal temporal dispersion, and normal conduction require delineation of the normal change in amplitude of the compound muscle action potential (CMAP) over a length of nerve. Effects of the recording site on CMAP amplitude and on its variation were studied in median and ulnar nerves of 13 healthy subjects. CMAPs were recorded from three sites: halfway along the muscles and 1 cm distal and proximal. Elbow–wrist amplitude percentages (CMAP%) were calculated. CMAP amplitudes varied considerably between sites and subjects. Amplitudes were maximal at the middle site in only 16 of 26 nerves. The site of maximal amplitude could not be identified on the basis of thumb anatomy. CMAP% was not related to CMAP amplitude, and differed by up to 32% between adjacent sites. CMAP formation involves spatial factors (electrode site, limb position, and limb anatomy), temporal factors (dispersion), and their interaction, explaining why CMAP% can exceed 100%. The site of the recording electrode affects CMAP amplitude and CMAP% to clinically relevant degrees. Standardisation of the recording site may improve reliability of CMAP% studies. © 1994 John Wiley & Sons, Inc.
The biphasic morphology of voluntary and spontaneous single muscle fiber action potentials
Authors: Dumitru Daniel , King John C. , van der Rijt William , Stegeman Dick F.
Published: January 2005

The extracellular morphology of single muscle fiber action potentials (SMFAPs) is anticipated by volume conductor theory to be triphasic. Single muscle fiber action potentials recorded during single muscle fiber studies (500 Hz to 20 kHz) usually appear triphasic; however, when recorded with an open bandwidth (1 Hz to 20 kHz) they are found to be biphasic. Fibrillation potentials recorded with a single fiber electrode and open bandwidth have identical biphasic morphologies as volitional SMFAPs. Computer simulations suggest that the intracellular action potential models currently used to derive simulated extracellularly recorded SMFAPs must have the repolarization phase considerably prolonged to yield the clinically recorded potentials. This implies that either the models presently used require significant modification, or there is some distortion of the transmembrane source current induced in needle recording studies such that biphasic and not triphasic potentials are detected. © 1994 John Wiley & Sons, Inc.
Putative effects of nerve extract on carbonic anhydrase III expression in rat muscles
Authors: Milot Julie , CǒTé Claude H. , Tremblay Roland R.
Published: January 2005

Carbonic anhydrase III (CA III), the predominant CA isoform in skeletal muscle is very sensitive to neuronal influences. We aimed to determine whether CA III expression could be influenced by neurotrophic factor(s) present in sciatic nerve extract (SNE). Intact muscles were thus compared with denervated soleus (SOL), extensor digitorum longus (EDL), and tibialis anterior (TA) muscles injected daily for 7 days with saline solution (SS) or with SNE. CA III activity was significantly increased in SS‐treated EDL and TA muscles compared to control (CTR), while SNE injections partially prevented this increase. There was no significant difference for CA III activity in the SOL between CTR, SS, and SNE groups. The CA III mRNA increase observed in response to denervation was reduced by 40% in SNE‐treated EDL and TA muscles. While SOL CA III mRNA level was not affected by denervation, a 52% decrease was observed with SNE. We concluded that neuronal modulation of CA III expression in type II fibers may involve a neurotrophic component. © 1994 John Wiley & Sons, Inc.
The all ulnar motor hand without forearm anastomosis
Authors: Sachs George M. , Raynor Elizabeth M. , Shefner Jeremy M.
Published: January 2005

Anomalous ulnar innervation of intrinsic hand muscles, inferred in a number of clinical series, has been documented only rarely in electrophysiological studies. Using near‐nerve and standard conduction studies we evaluated 2 cases with nearly exclusive ulnar innervation of hand muscles. There was no evidence of anomalous communication in the forearm. Digital sensory fibers were normally distributed in median and ulnar nerves. The anomalous motor innervation most likely results from palmar communication between ulnar and median branches (Riche‐Cannieu anastomoses). The normal distribution of digital afferents suggests that such anastomoses are formed primarily by motor axons.© 1995 John Wiley &Sons, Inc.
Electrodiagnostic evaluation of fecal incontinence
Authors: Cheong Denis M. O. , Vaccaro Carlos A. , Waxner Steven D. , Salanga Virgilio D. , Phillips Reginald C. , Hanson Maurice R.
Published: January 2005

The aim of this study was to assess the utility of electrodiagnostic testing (EDT) for the evaluation of fecal incontinence (FI). Over a 5‐year period, 225 patients (174 females) with FI were prospectively studied with anal manometry, anal ultrasonography, anal electromyography (AEMG), and pudendal nerve terminal motor latency (PNTML) assessment. The mean age was 60 (range 12–94) years. Causes of FI identified by clinical evaluation were obstetric injuries (45), rectal prolapse (43), iatrogenic or other trauma (42), neurologic disease (23), and idiopathic (72). EDT revealed abnormalities in 76% of patients. The incidence of pudendal neuropathy (PN) was 36% (bilateral 21%, unilateral 15%). Patients with PN were older than were those with normal PNTML (mean 71 vs. 63 years; P < 0.002). No relationship between squeeze pressure and PN could be demonstrated (P = 0.9). Reduced motor unit potential (MUP) recruitment on AEMG was present in 60% and was associated with decreased squeeze pressure (P < 0.001) and increased MUP polyphasia (P < 0.001). Concurrence of AEMG and anal ultrasonographic findings was observed in 35 of 41 patients (84%). Defects were overlooked in one study but identified by the other on three occasions, each. Moreover, 8 of 22 patients with demonstrated sphincter defects had unsuspected PN or extensive sphincter injury on AEMG that precluded sphincter repair. In conclusion, EDT proved to be a valuable tool in the evaluation and subsequent treatment of patients with FI. © 1995 John Wiley & Sons, Inc.
Neurological multisystem manifestation in multiple symmetric lipomatosis: A clinical and electrophysiological study
Authors: Naumann Markus , Schalke Bertold , Klopstock Thomas , Reichmann Heinz , Lange Klaus W. , Wiesbeck Gerhard , Toyka Klaus Viktor , Reiners Karlheinz
Published: January 2005

Multiple symmetric lipomatosis (MSL) is characterized by a typical neck and shoulder distribution of subcutaneous lipomata and is often associated with polyneuropathy. Occasionally, the central nervous system (CNS) can be involved. Twelve of 14 patients in this retrospective study had clinical or electrophysiological evidence of a predominantly axonal polyneuropathy. Among those were 10 with alcohol abuse, but 2 patients without alcohol abuse also showed clinical or electrophysiological polyneuropathy. Clinical CNS involvement was present in 4 patients. CNS dysfunction was documented by evoked potentials in 8 subjects [prolonged latency or low amplitude of the motor response following cortical magnetic stimulation (4 patients), abnormal visually evoked potentials (4 patients) or somatosensory evoked potentials (SEP) (4 patients)]. These findings were compared to 10 chronic alcoholics without clinical signs of MSL. Five of these showed mild sensory neuropathy. Additionally, 2 also had delayed SEP latencies. Motor evoked potentials were normal in all controls. We propose that the multisystem involvement in MSL demonstrated here cannot be attributed to alcohol abuse alone. Biochemical studies have suggested mitochondrial dysfunction as the basis of the widespread neurological pathology in MSL. © 1995 John Wiley & Sons, Inc.
Myophosphorylase deficiency associated with rhabdomyolysis and exercise intolerance in 6 related charolais cattle
Authors: Angelos S. , Valberg S. J. , Smith B. P. , McQuarrie P. S. , Shanske S. , Tsujino S. , DiMauro S. , Cardinet G. H.
Published: January 2005

A Charolais calf presented to the Veterinary Medical Teaching Hospital with a history of recumbency following forced exercise. The calf was unable to stand, and had severe rhabdomyolysis, dehydration, and electrolyte imbalance. Blood selenium concentrations were within normal limits. A complete absence of histochemical staining for phosphorylase was apparent in muscle biopsies. Five other animals in the herd also had exercise intolerance and had a complete absence of phosphorylase staining in muscle biopsies. Biochemical analyses confirmed a deficiency of myophosphorylase (range 0–0.3 μmol/g per minute: normals 15–27) with normal to slightly elevated muscle glycogen concentrations. Pedigrees from all affected animals showed a common ancestor on the sire's and dam's side of each phosphorylase‐deficient animal, suggesting an autosmal recessive transmission. Although myophosphorylase deficiency was described in humans (McArdle's disease) over 40 years ago, these cattle represent the first animal model for this disease. © 1995 John Wiley & Sons, Inc.
A quantitative study of the pancuronium antagonism at the motor endplate in human organophosphorus intoxication
Authors: Besser Roland , Gutmann Ludwig
Published: January 2005

Nine patients with organophosphorus (OP) intoxication developing neuromuscular transmission defects were given pancuronium 1, 2, or 4 mg intravenously (IV). Thirteen patient controls with hypoxic encephalopathy received similar dosages. The responses were monitored electrophysiologically using single and repetitive nerve stimulation (20 and 50 Hz). In OP patients, pancuronium did not alter the amplitude of the single CMAP, whereas its repetitive discharges were reduced. Severe neuromuscular blocks were reversed only partially by pancuronium 4 mg. In less severe blocks, 1 and 2 mg resulted in marked improvement. In the patient controls, pancuronium 4 mg induced a severe neuromuscular block but not with 1 and 2 mg. Pancuronium dosages necessary to reverse severe OP‐induced neuromuscular blockade produce a neuromuscular block when AChE activity is normal. Low dosages have little effect on normal neuromuscular transmission, but improve the block to a mild degree and may be useful as part of treatment in OP intoxications. © 1995 John Wiley & Sons, Inc.
A fractal characterization of the type II fiber distribution in the extensor digitorum longus and soleus muscles of the adult rat
Authors: Arsos George A. , Dimitriu Petros P.
Published: January 2005

A method is proposed for the quantitative characterization of fiber type spatial distribution by means of the (correlation) fractal dimension. The method is applied to type II fiber distributions of the soleus and extensor digitorum longus muscles of the adult rat. The results obtained suggest that these distributions have fractal properties with a strong tendency for spreading, more pronounced in soleus muscle. The density of muscle fibers or the age do not seem to alter the features of the distribution. Computer‐generated random patterns have virtually the same fractal dimension as the extensor digitorum longus distributions but fail to approximate those of the soleus muscle. This fractal method could find application as an alternative in the quantitative assessment of the fiber type grouping. © 1995 John Wiley & Sons, Inc.
A new approach to motor unit estimation with surface EMG triggered averaging technique
Authors: Shahani Bhagwan T. , Fang Jianjun , Dhand Upinder K.
Published: January 2005

A new method for estimating the number of motor units using a surface EMG triggered averaging technique is described. This method provides an estimation of mean motor unit potential (MUP) amplitude at different leveles of contraction, which can be utilized to estimate the number of motor units in a given muscle. Motor unit count estimated in abductor pollicis brevis (APB) muscle of 11 normal healthy subjects ranged from 131 to 371 with a mean of 246 ± 68. In our preliminary study of patients with lower motor neuron lesions, there was a significant reduction in the number of motor units. We believe our new noninvasive method of motor unit counting is a relatively simple and reproducible physiological technique.© 1995 John Wiley &Sons, Inc.
Sources of error in the spike‐triggered averaging method of motor unit number estimation (MUNE)
Authors: Bromberg Mark B. , Abrams Judith L.
Published: January 2005

Motor unit number estimation (MUNE) is an electrophysical technique to estimate the number of motor units innervating a muscle or muscle group. MUNE may be useful as a measure of progression of lower motor neuron loss in amyotrophic lateral sclerosis (ALS). Several methods of MUNE have been developed. The spike‐triggered averaging method can be readily performed on EMG machines with signal averaging capabilities and is suitable for estimating the number of motor neurons innervating proximal muscles. We have used MUNE as a measure of disease state in a drug efficacy trial for ALS. From our experience with this method we have identified sources of error which can affect MUNE accuracy. We have investigated these sources and report their effect on MUNE.© 1995 John Wiley & Sons, Inc.
Decreased heart rate variability in amyotrophic lateral sclerosis
Authors: Pisano Fabrizio , Miscio Giacinta , Mazzuero Giorgio , Lanfranchi Paola , Colombo Roberto , Pinelli Paolo
Published: January 2005

Autoregressive spectral analysis of heart rate variability (HRV) was performed in 29 patients with amyotrophic lateral sclerosis (ALS) and 33 age‐matched healthy subjects to evaluate the involvement of the autonomic nervous system. HRV analysis provides a means to recognize low (LF) and high (HF) frequency components, respectively mediated by sympathetic and parasympathetic heart control. An increase in the mean heart rate at rest (P< 0.001), a decrease in standard deviation of R‐R interval as well as in PNN50 (P< 0.001), and an increase in the LF/HF component ratio (P< 0.01) were found in the ALS patients, indicating a vagal–sympathetic imbalance. These alterations were not related to the clinical features and to the duration of the disease. Our results suggest a subclinical involvement of the autonomic nervous system in ALS, particularly affecting parasympathetic cardiovascular control. © John Wiley & Sons, Inc.
Comparison of contractile properties between developing and regenerating soleus muscle: Influence of external calcium concentration upon the contractility
Authors: Louboutin Jean‐Pierre , Fichter‐Gagnepain Valerie , Noireaud Jacques
Published: January 2005

In newborn rat skeletal extensor digitorum longus (EDL) muscle, it has been found that an influx of calcium from the extracellular medium is necessary for contraction, in contrast to the situation observed in adult EDL muscle. The aim of the present study was to determine the influence of the extracellular calcium concentration ([Ca]o) upon the contractile responses elicited in developing as well as in regenerating (notexin‐injected) soleus (SOL) muscle. A morphological study was performed to follow the steps of postnatal development and regeneration in SOL muscle. In nominally calcium‐free solution, the amplitudes of the twitch and tetanic tensions were greatly reduced in 1–14‐day‐old developing SOL muscles, as well as in notexin‐injected SOL muscles. With longer times after birth, twitch and tetanic tensions of SOL muscle were less affected by the absence of calcium. This contrasts with notexin‐injected SOL muscle in which the amplitudes of the contractions remained strongly dependent on [Ca]o. The present finding suggests that some functional characteristics are different in regenerating muscle fibers and may be of interest in the evaluation of the contractile properties of muscles in which injections of genetically engineered or not autologous myoblasts or viral vector have been performed. © John Wiley & Sons, Inc.
Correlates of mototr unit size, recritment threshold, and h‐refles jitter
Authors: Jabre Joe F. , Rainville James , Salzsieder Byron , Smuts Johnnes , Limke Janet
Published: January 2005

The aim of this research was to study the neurophysiology of the anterior horn cell (AHC) using single‐fiber EMG (SFEMG) study of the flexor carpi radialis (FCR) H‐reflex. Twelve men and 7 women, ages 20–80 years, were studied. The mean H‐jitter was 138 ± 59 μs. H‐jitter increased with age (while the M‐jitter did not) and was greater in men than in women. There was a direct correlation between the H‐jitter and H‐latency which was used as an indirect measure of the AHC's size. Given that small AHCs have a higher input resistance than large ones, the H‐jitter can be used as an indirect indicator of the AHC's input resistance and therefore its size. When subjects fell asleep, the H‐jitter increased over tenfold the baseline value, reising the possibility of an alternative, oligosynaptic pathway. H‐reflex jitter studies provide a useful clinical neurophysiological tool for the study of AHC physiology. © John Wiley & Sons, Inc.
Quantitation of heteroplasmy of mitochondrial trnaLeu(UUR) gene using PCR‐SSCP
Authors: Tanno Yoshinori , Yoneda Makoto , Tanaka Keiko , Tanaka Hajime , Yamazaki Motoyoshi , Nishiawa Masatoyo , Wakabayashi Koichi , Ohama Eisaku , Tsuji Shoji
Published: January 2005

We have devised a novel method for quantitative analysis of the MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) tRNALeu(UUR) mutation of mitochondrial DNA using a PCR‐SSCP (polymerase chain reaction–single‐strand conformation polymorphism) method, and compared the results obtained using the PCR‐SSCP method with those obtained using other methods including Southern blotting, last one cycle hot PCR, and conventional PCR‐RFLP (restriction fragment length polymorphism). The standard curve obtained using the PCR‐SSCP method is linear, with a correlation coefficient of 0.999; it was determined that this method is more accurate than other methods for quantitative analysis. The PCR‐SSCP method does not require restriction digestions, thereby avoiding potential problems of partial digestions or heteroduplex formation during PCR. The method is quite simple and should have a broad range of application for quantitation of mutant mtDNAs in various mitochondrial encephalo‐myopathies. We applied the method for quantitation of mutant mitochondrial DNA carrying a single base substitution in the tRNALeu(UUR) gene in two autopsied cases of MELAS. In both cases, the mutant mtDNA is abundantly present (82–95%) with little variation among tissues. © 1995 John Wiley & Sons, Inc.
Extracellular space in the central nervous system of the leech, Mooreobdella fervida
Authors: Van Harreveld A. , Khattab F. I. , Steiner Jana
Published: January 2005

The ganglia and connectives of the ventral nerve cord of a leech (Mooreobdella fervida) were subjected to fixation by freeze substitution. This method is believed to preserve the water distribution in the tissue more faithfully than conventional fixation, but has the disadvantage that only the superficial 10 to 15 μU of these structures can be examined. Electron micrographs of this material showed the following differences from nervous tissue fixed by immersion in an osmium tetroxide solution. The lamellae of the packet glia cells were narrower and the extracellular spaces between them were wider than in conventionally fixed material. The cytoplasm of the lamellae was finely granular and lacked the vacuoles which characterize this tissue when fixed by immersion. In the neuropil the nervous elements tended to be separated by glial material which sometimes consisted of a single sheet, but often of several lamellae with rather more extracellular space than in conventionally fixed material. In the connectives thin axons were present in bundles containing little or no glia but surrounded by glial lamellae. The fibers had a rounded appearance and these axon fields showed an appreciable extracellular space. The large axons showed irregular but generally more rounded profiles than in conventionally fixed material. They were usually individually enveloped by glial lamellae with rather ample space between them. In the neuropil and the connective fixed by immersion in OsO4 solutions the extracellular space consisted of the narrow 100 to 150 Å spaces between the tissue elements typical for OsO4 fixed material.
Neurotrophic‐hormonal interaction in the regulation of taste buds in the rat's vallate papilla
Authors: Zalewski Andrew A.
Published: January 2005

Prolonged treatment of castrated‐male rats with testosterone causes the development of taste buds in abnormal locations in the vallate papilla (i.e., upper surface of the papilla). Since taste buds are morphologically dependent on a trophic factor delivered to them via intact gustatory nerves, investigations of the possible role of testosterone as a trophic agent were undertaken. The effects of testosterone propionate on taste buds were studied in normal male and female, castrated‐male, and male rats in which the taste buds were totally denervated. There was no apparent change in the number, distribution, or appearance of the taste buds normally found in the trench walls of testosterone treated normal or castrated rats. However, in the normal‐male and castrated‐male rats, 1–3 taste buds were found on the top surface of the papilla 6 weeks after treatment. No new buds were seen at 1 or 2 weeks, nor were any seen in hormonally treated females, or in control animals injected with sesame oil alone. Furthermore, testosterone did not maintain old or initiate new taste bud formation in the denervated papilla. Thus, testosterone in the form, doses, and times employed, could not subserve the trophic function of intact gustatory nerves. The results however indicate that new taste bud formation is the result of a nerve–hormone interaction, and not a change induced by castration and subsequent testosterone treatment. Further studies of the nerve–hormone interaction involved in taste bud formation seem indicated.
Divalent cations and electrical properties of cortical cells
Authors: Kelly J. S. , Krnjevic K. , Somjen G.
Published: January 2005

1. Ca2+ and Mg2+ have been applied by microiontophoresis, mainly in doses of 20–200 nA, to cortical cells in cats under Dial.

2. Both divalent cations had a similar action, causing a sharp but reversible fall in the electrical excitability of neurones.

3. Ca2+ was slightly more potent than Mg2+; in small doses the two cations had an additive effect.

4. The fall in neuronal excitability was not associated with definite changes in membrane potential or resistance.

5. The amounts of Ca2+ and Mg2+ applied did not cause any obvious alteration in synaptic efficiency.

6. The membrane properties of unresponsive cells (probably neuroglia) were not markedly altered by the divalent ions, except for an occasional increase in membrane resistance.
Neuromuscular transmission in cultures of adult human and rodent skeletal muscle after innervation in vitro by fetal rodent spinal cord
Authors: Crain Stanley M. , Alfei Laura , Peterson Edith R.
Published: January 2005

Electrophysiologic analyses have been carried out on in vitro‐coupled explants of fetal rodent spinal cord and adult skeletal muscle of human as well as rodent origin. The studies demonstrate that characteristic neuromuscular transmission can develop and be maintained in these unusual tissue combinations during long‐term culture.

After coupling periods of 2–7 weeks in vitro, selective stimulation of spinal cord evokes widespread coordinated contractions in the muscle tissue. Simultaneous microelectrode recordings of cord and muscle responses to local cord, or ventral root, stimuli show that muscle action potentials (and contractions) generally occur with latencies of several msec after onset of cord discharges. Similar temporal relations are often seen during spontaneous rhythmic discharges of the coupled cord and muscle tissues. Long series of repetitive discharges, at 2–5 sec intervals, may occur synchronously between these cord and muscle explants, in response to single cord (or dorsal‐root ganglion) stimuli, and they may also appear spontaneously.

d‐Tubocurarine (1–10 μg/ml) selectively and reversibly blocks neuromuscular transmission in these cultures. Eserine accelerates recovery of normal function. Spontaneous repetitive fibrillations of many of the cultured muscle fibers are observed sporadically, and these contractions often continue unabated after block of neuromusclar transmission by d‐tubocurarine. Many of the fibers which show asynchronous fibrillations are probably not innervated (as in denervated muscle in situ). In some cases, however, extracellular as well as intracellular recordings indicate that similar fibrillations may also occur in fibers which are clearly innervated.

Repetitive cord and muscle discharges are greatly augmented after introduction of strychnine. Complex rhythmic oscillatory (ca. 10/sec) afterdischarges generated in strychninized cord explants lead to similarly patterned muscle discharges (and contractions), which may also occur, at, times, in normal medium.
Isolation and characterization of membranes from rat cerebral cortex
Authors: McBride W. J. , Mahler H. R. , Moore W. J. , White F. P.
Published: January 2005

The subcellular fractionation of rat cerebral cortex has been extended to an examination of all fractions in the zones comprising synaptosomes (obtained from unlysed crude mitochondrial fractions [P2]) and synaptosomal membrances (from lysed P2), with emphasis on junctional complexes. The parameters investigated included: (a) ultrastructure, (b) marker enzymes, (c) analytical acrylamide‐gel electropherograms for insoluble proteins, (d) rate of incorporation of labeled 3H‐leucine into constituent proteins in slices, and (e) cytochemical localization of carbohydrate‐containing molecules. The results of these studies have provided the first stage for an analysis of the structure and dynamic chemistry of synaptic systems in the rat brain.
The cholinergic nature of the cercal nerve‐giant fiber synapse in the sixth abdominal ganglion of the American cockroach, Periplaneta americana (L.)
Authors: Shankland D. L. , Rose J. A. , Donniger C.
Published: January 2005

The effects of cholinergic drugs on transmission at the cercal nervegiant fiber synapse in the desheathed sixth abdominal ganglion of the American cockroach, Periplaneta americana (L.) were evaluated.

When due consideration was given to slow diffusion rates of drugs into the ganglion, and to the enzymic hydrolysis of exogenously applied choline esters by endogenous cholinesterase, the synapse was found to respond in ways consistent with cholinergic transmission. Botulinus toxin, magnesium, and hemicholinium‐3, all working presynaptically blocked transmission. Atropine, D‐tubocurarine, and hexamethonium produced non‐depolarizing blockade at concentrations of 10−7 M or 10−6 M. Atropine and d‐tubocurarine also blocked the action of exogenously applied acetylcholine. Postsynaptic responses were obtained from acetylcholine (10−7 M), acetyl ß‐methyl choline (10−8 M), and nicotine (10−8 M).

The results were discussed with respect to criteria which have been proposed for the indentification of transmitters. It was concluded that considering all of the information available on the cercal nerve‐giant fiber synapse, the transmitter is almost certainly Ach.
The relation of cerebral dominance and handedness to visual evoked potentials
Authors: Gott Peggy S. , Boyarsky Louis L.
Published: January 2005

Evoked responses can be characterized with respect to latency and amplitude.

The latency of the evoked response depends upon whether the person is right‐handed or left‐handed. In right‐handed subjects, the left (dominant) hemisphere has a longer latency than the right when used as a direct hemisphere. Similarly, when the so‐called dominant (right) hemisphere of left‐handed subjects is used as the direct hemisphere it shows a longer latency than when the non‐dominant hemisphere is used. This has been interpreted as an indication that a longer processing time is required in cortical or subcortical systems.

Another asymmetry in response occurs with respect to amplitude. While right‐handed persons show no difference in the amplitude of the response between right (direct) and left (direct) hemispheres, this is not so for left‐handed individuals in whom the response of the right (so‐called dominant) hemisphere is larger when used as the direct hemisphere.

The responses from left‐ and right‐handed people were compared to one another. The left (dominant) hemisphere of right‐handed persons has a longer latency than the left (non‐dominant) hemisphere of the left‐handed person. Similarly, the latency of the responses from the right (dominant) hemisphere of the left‐handed subjects is longer than that from the right (non‐dominant) hemisphere of right‐handed subjects.

The amplitude of responses recorded from the right (dominant) hemisphere of left‐handed people appears to be larger in general than those from the right (non‐dominant) hemisphere of right‐handed people, but the data were not statistically significant.