bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calcium‐tension relationships of muscle fibers from patients with periodic paralysis
Authors: Ruff Robert L. 
Published: January 2005

AbstractLateral gastrocnemius muscle biopsies from a 26‐year‐old man with hyperkalemic periodic paralysis and a 23‐year‐old man with hypokalemic periodic paralysis were studied. Both patients came from families in which older relatives had developed a vacuolar myopathy in association with their periodic paralysis. Muscle fibers were chemically skinned, and individual fibers were studied with a low‐compliance strain gauge. The tension generated by fibers was studied in baths with calcium concentrations from 10‐8 mol/L to 2.5 × 10‐5 mol/L. The Ca‐tension relationships and maximal tensions (normalized to fiber cross‐sectional area) of fast and slow twitch fibers were indistinguishable from those found in fibers from 5 normal subjects. The results reinforce earlier findings which suggested that loss of Ca‐induced myofibril contraction was not the cause of paralysis in periodic paralysis.
Conduction block in diabetic neuropathy
Authors: Abu‐Shakra Sawsan R. , Cornblath David R. , Avila Orlando L. , Chaudhry Vinay , Freimer Miriam , Glass Jonathan D. , Reim Johannes W. , Ronnett Gabriele V. 
Published: January 2005

AbstractSymmetric sensorimotor polyneuropathy is a common complication of diabetes. Sensory and motor evoked amplitudes and conduction velocities are reduced. Both demyelination and axon loss have been reported in pathologic studies. Conduction block (CB), a manifestation of segmental demyelination, has not been previously studied in diabetic neuropathy. We determined the prevalence of conduction block in patients with diabetes by analyzing electrodiagnostic data from 24 diabetics. Conduction block was defined as a >20% drop in peak‐to‐peak amplitude, and a <15% change in negative‐peak duration between proximal and distal stimulation sites. A total of 76 nerve segments were studied. The criteria for conduction block were met in only 6 segments in 6 patients. The mean decrease in peak‐to‐peak amplitude between stimulation sites was 28% (range 21% to 40%). We conclude that conduction block over long nerve segments is uncommon in diabetic neuropathy, and, if present, suggests that other causes for neuropathy in diabetic patients should be sought.
Nerve conduction studies in experimental non‐freezing cold injury: II. Generalized nerve cooling by limb immersion
Authors: Kennett Robin P. , Gilliatt Roger W. 
Published: January 2005

AbstractAfter immersion of the hind limb of the rabbit, up to the lower thigh, in a waterbath, at 1°C for 10 to 14 hours under light anesthesia, there was evidence of persistent nerve damage to the tibial nerve, which varied in severity in different animals. Nerve conduction studies, carried out within 24 hours of removal from the bath, showed that in a proportion of the motor and/or afferent fibers, there was conduction failure between the knee and ankle. This was followed, over the next 48 hours, by distal degeneration of the affected fibers. No persistent conduction block was seen. After distal degeneration had occurred, maximal conduction velocity was mildly reduced, suggesting that the fastest‐conducting motor and afferent fibers had been particularly affected. Morphological studies confirmed preferential large myelinated fiber degeneration, the earliest lesions being seen in the leg at the level of the upper calf. Limb edema was not seen after cooling, and there was no histological evidence of muscle necrosis or damage to blood vessels. No abnormalities were seen in 4 control animals after hind limb immersion for 12 hours at temperatures of 30 to 35°C. Possible reasons for the proximal site of myelinated nerve fiber damage during hindlimb cooling are discussed.
Muscular dystrophy with separate clinical phenotypes in a large family
Authors: Udd Bjarne , Kääriänen Helena , Somer Hannu 
Published: January 2005

AbstractThis report describes a large consanguineous family with muscular dystrophy in 23 patients showing intrafamilial variation of clinical expression. One main variant appeared in the first decade with proximal muscle weakness progressing over the next 20 years to wheelchair confinement, and appeared compatible with classical limb‐girdle muscular dystrophy. The other main variant showed onset of distal muscle weakness in lower limbs in the third or fourth decade, progressing very slowly without greater disability throughout the lifetime. Tibial muscle weakness and wasting were clinical landmarks in this variant, but computed tomography of skeletal muscle revealed focal areas of fatty degeneration also in truncal, pelvifemoral, and distal leg muscles in a way not previously reported in distal myopathy. The overall difference in clinical findings between these main variants would suggest 2 separate genetic entities, genealogical data makes a common genetic background possible.
Comparison of vibrotactile thresholds with physical examination and electrophysiological assessment
Authors: Gerr Fredric , Letz Richard , Hershman Dawn , Farraye Joseph , Simpson David 
Published: January 2005

AbstractMeasurement of cutaneous vibrotactile thresholds may be useful for assessment of the functional integrity of the somatosensory system. To validate a rapid method of determining vibrotactile thresholds that uses a commercially available electromechanical device, vibrotactile thresholds were compared with standardized physical examination findings of sensory function and electrophysiological parameters in 79 patients referred to the Mount Sinai Hospital Neurophysiology Laboratory for clinical electrophysiological evaluation. A statistically significant monotonic association between graded physical examination of vibration perception and vibrotactile threshold was observed for all digits tested in the upper and lower extremities. Statistically significant associations were also observed between vibrotactile thresholds and a variety of electrophysiological measures of the median, ulnar, tibial, peroneal, and sural nerves. The strongest associations were observed between great toe vibrotactile thresholds and late response latencies measured in nerves in the lower extremities. Determination of vibrotactile thresholds may be useful in settings where quantitative measures of large fiber nerve function are desirable and electrophysiological study is not feasible.
Interobserver agreement in the assessment of muscle strength and functional abilities in Guillain‐Barré syndrome
Authors: Kleyweg Ruud P. , Van Der Meché Frans G. A. , Schmitz Paul I. M. 
Published: January 2005

AbstractIn studies of Guillain‐Barré syndrome, functional deficit is usually assessed according to a functional scale consisting of several categories. The level of interobserver agreement in this scoring method is not known; furthermore, this method seems to be insensitive when applied to bedridden and artificially ventilated patients. We have developed an additional score (MRC‐sumscore), reflecting muscle strength in general. Both scoring methods, tested in Guillain‐Barré patients, have an almost perfect interobserver agreement. For the functional score k = 0.85, and for the MRC‐sumscore r2 = 0.96. The MRC‐sumscore is easily assessed and more sensitive than the functional score when patients are bedridden or artificially ventilated.
Myopathy with thick filament (myosin) loss following prolonged paralysis with vecuronium during steroid treatment
Authors: Danon Moris J. , Carpenter Stirling 
Published: January 2005

AbstractA 20‐year‐old female hospitalized with status asthmaticus was treated with bronchodilators, antibiotics, and high‐dose corticosteroids, and was paralyzed with vecuronium for 10 days to facilitate mechanical ventilation. When this was discontinued, she was found to have a flaccid quadriplegia with areflexia and 4‐fold elevation in serum creatine kinase. A muscle biopsy showed extensive loss of thick (myosin) myofilaments, sometimes in corelike distribution, with relative preservation of thin (actin) filaments and Z‐discs. Muscle strength returned to normal after 2 months. The pathological lesion in this patient's muscle fibers resemble those in rats treated with high doses of corticosteroids following denervation.
Anconeus muscle: A human muscle preparation suitable for in‐vitro microelectrode studies
Authors: Maselli Ricardo A. , Mass Daniel P. , Distad Barbara J. , Richman David P. 
Published: January 2005

AbstractWe performed in‐vitro microelectrode studies on the anconeus muscle of 14 patients with diseases of neuromuscular transmission. The procedure detected marked abnormalities in all patients studied, and may therefore be a valuable technique for the study of human disorders of neuromuscular transmission.
Estimation of conduction velocity of Aδ fibers in humans
Authors: Kakigi Ryusuke , Endo Chiyoko , Neshige Ryuji , Kuroda Yasuo , Shibasaki Hiroshi 
Published: January 2005

AbstractConduction velocity of Aδ fibers of the human peripheral nerves was measured by using pain‐related somatosensory evoked potentials following CO2 laser stimulation. It was found to be approximately 9 m/s in the forearm as well as in the lower leg. Because conventional conduction study using electric stimulation reflects only functions of large myelinated fibers related to deep proprioceptive and tactile sensations, the present noninvasive and simple, novel method is the only laboratory examination currently available to investigate physiological functions of the small diameter fibers mediating pain‐temperature sensations.
High pancuronium sensitivity of axonal nicotinic‐acetylcholine receptors in humans during organophosphate intoxication
Authors: Besser Roland , Vogt Thomas , Gutmann Ludwig , Wessler Ignaz 
Published: January 2005

AbstractThe effect of low‐dose pancuronium on neuromuscular transmission was studied in 2 patients during the early and late stages of severe organophosphate intoxication. Single evoked compound muscle action potentials (CMAP) were followed by repetitive discharges and a decrement‐increment (D‐l) phenomenon with 10‐, 20‐, and 50‐Hz supramaximal nerve stimulation. Intravenous pancuronium, 1 mg, abolished the D‐l phenomenon, while the repetitive discharges of the CMAP were only partially reduced. It is postulated, that the disappearance of the D‐l phenomenon with persistence of the CMAP repetitive discharges results from blockade of nicotinic‐acetyl‐choline receptors located on the terminal axon responsible for stimulus‐induced antidromic backfiring. This response to a very low dose of pancuronium indicates a high sensitivity of the axonal nicotinic‐acetylcholine receptor to pancuronium in humans, as had been previously postulated from animal experiments.
Abnormalities in the sensory action potential in patients with amyotrophic lateral sclerosis
Authors: Shefner Jeremy M. , Tyler H. Richard , Krarup Christian 
Published: January 2005

AbstractSensory function in patients with amyotrophic lateral sclerosis (ALS) is thought to be normal; however, there is convincing morphologic evidence that sensory systems are affected in addition to motor systems. In this study, compound sensory action potentials were recorded with near nerve electrodes from 18 patients with ALS. Up to 1024 responses were averaged at high gain to determine minimum conduction velocity; that is, the conduction velocity of the slowest conducting component of the sensory action potential. Nine of 18 patients had abnormally reduced minimum conduction velocity, even when peak‐to‐peak amplitude and maximum conduction velocity (calculated from the latency to the initial positive peak) were normal. Only 3 of 18 patients showed abnormalities in peak‐to‐peak amplitude. Thus, subtle abnormalities in the sensory action potential can be detected in many patients with ALS.
Interindividual variability of central delay changes in the soleus H reflex pathway
Authors: Abbruzzese Michele , Reni Lizia , Favale Emilio 
Published: January 2005

AbstractCentral delay (CD) changes in the soleus H reflex pathway, as demonstrated by variations in the time interval between afferent (P1) and efferent (P2) neurographic volleys underlying the reflex response, were assessed in a group of normal subjects, both during the steady state and after homosynaptic spatial summation of afferent impulses. The maximal range of CD changes, regardless of whether “spontaneous” or provoked, showed significant interindividual differences whose size was positively related to the Hmax/Mmax ratio, provided that the extension of the subliminal fringe was suitably normalized. Comparatively similar variations in amplitude of the reflex motoneuronal discharge under different experimental conditions can be associated with different CD changes. Indeed, “spontaneous” CD fluctuations occurring during the steady state were consistently greater than CD reductions provoked by spatial summation, the gap size being negatively related to the Hmax/Mmax ratio.
Single fiber EMG reference values: A collaborative effort
Authors:   Ad Hoc Committee of The AAEM Special Interest Group on Single Fiber EMG, Gilchrist James M. 
Published: January 2005

AbstractSingle fiber electromyography (SFEMG) measurements of fiber density and jitter are used in the diagnosis of a variety of peripheral nervous system disorders. However, the normal values of these measurements for most muscles and age groups are not well documented in the literature. We present a retrospective and prospective multicenter collection of SFEMG jitter and fiber density data from control subjects obtained for the purpose of defining reference values for many muscles and different ages. The data and calculated upper limits for fiber density, individual pair jitter, and mean jitter are presented for each muscle in tabular and graphical format, for different age groups.
The function of large and small nerve fibers in renal failure
Authors: Angus‐Leppan Heather , Burke David 
Published: January 2005

AbstractPrevious clinical and neurophysiological studies of uremic neuropathy have focused almost exclusively on the function of large sensory and motor axons. The sensations of heat and cold depend on the function of unmyelinated afferents and small myelinated afferents, respectively, and these sensations can be quantified using a standardized psychophysical technique. Thermal thresholds were measured in 20 patients with end‐stage renal failure to determine the extent of small afferent fiber involvement and to compare this with the clinical and electrophysiological evidence of large fiber involvement. Whereas abnormalities of standard nerve conduction studies were found in 16 patients, abnormal thermal thresholds were found in only 6 patients. In the nerve conduction studies, the amplitudes of nerve potentials were reduced more than their conduction velocities, consistent with an axonopathy. This study found little evidence of significant dysfunction of small afferent fibers in end‐stage renal failure and, when such changes occurred, they did not correlate with the clinical evidence of polyneuropathy. The functional sparing of axons of small diameter is consistent with the relative sparing of these axons in pathological studies.
Improved inching method for the diagnosis and prognosis of carpal tunnel syndrome
Authors: Imaoka H. , Yorifuji S. , Takahashi M. , Nakamura Y. , Kitaguchi M. , Tarui S. 
Published: January 2005

AbstractA modified sensory “inching” method for the electrodiagnosis of carpal tunnel syndrome (CTS) Is described. The median nerve as stimulated at the cubital portion, with 8 channel recording electrodes placed along the nerve across the carpal tunnel. In most of the CTS cases, there was a conductive abnormality from 3 to 4.5 cm distal to the proximal ending of the flexor retinaculum. Subjects'; values, obtained by subtracting the theoretical latency from the measured latency, which were more than 0.6 ms, could not be improved by conservative therapy. As we could determine from subtle change at the short span of nerve condcution, below the electrodes from the proximal to the affected site of the carpal tunnel, this method provides high sensitivity and specificity for the diagnosis of CTS.
Growth and development of human muscle: A quantitative morphological study of whole vastus lateralis from childhood to adult age
Authors: Lexell Jan , Sjöström Michael , Nordlund Ann‐Sofie , Taylor Charles C. 
Published: January 2005

AbstractThe mechanisms underlying the increase in volume of muscle tissue, and the functional development of muscle fibers from childhood through adolescence to adult age, have been studied. Cross sections of autopsied whole vastus lateralis muscle from 22 previously physically healthy males, 5 to 37 years of age, were prepared enzyme histochemically (myofibrillar ATPase) and examined morphometrically. The data obtained on muscle crosssectional area, size, total number, and proportion of type 1 (slow‐twitch) and type 2 (fast‐twitch) fibers were analyzed using linear regression techniques. The results show that the increase in muscle cross‐sectional area from childhood to adult age is caused by an increase in mean fiber size. This is accompanied by a functional development of the fiber population: the proportion of type 2 fibers increases significantly from the age of 5 (approx. 35%) to the age of 20 (approx. 50%), which, in the absence of any discernible effect on the total number of fibers, is most likely caused by a transformation of type 1 to type 2 fibers.
Comparison of electric and magnetic coil stimulation in the supraclavicular region
Authors: Cros Didier , Gominak Stasha , Shahani Bhagwan , Fang Jianjun , Day Bruce 
Published: January 2005

AbstractWe compared the compound motor action potentials (CMAPs) evoked in the biceps, triceps, and abductor digiti minimi (ADM) muscles by conventional electrical stimulation at Erb's point (EP), and by magnetic coil stimulation of the supraclavicular region in 11 normal subjects. We found that magnetic coil stimulation was less effective than conventional stimulation in activating motor fibers in the brachial plexus in 45% of the recordings analyzed. CMAP amplitudes greater than those obtained with EP electrical stimulation were seen in 16% of recordings with supraclavicular magnetic stimulation, and in 33% of recordings with cervical magnetic stimulation, indicating that EP electrical stimulation is submaximal in a large proportion of cases.
Single motor unit H‐reflex in motor neuron disorders
Authors: Soliven Betty , Maselli Ricardo A. 
Published: January 2005

AbstractThe latency fluctuation of single motor unit potentials (MUPH) in the H‐reflex is greater than the latency fluctuation of MUPs in the direct (MUPM) and recurrent (MUPF) responses. This has been attributed to the variability in the impulse generation at the site of nerve stimulation, and to the variation in the synaptic delay at the anterior horn cell. We studied the latency fluctuation of single motor unit H‐reflex in patients with motor neuron disorders (MND) in comparison with normal subjects. The mean jitter of the H‐reflex was 264.3 ± 17.8 μs (mean ± SEM) in 30 MUPH recorded from 10 patients with ALS, 302.7 ± 25.2 μs in 16 MUPH from 6 patients with chronic motor neuron diseases, as compared with 137.4 ± 7.3 µs in 34 MUPH recorded from 10 normal subjects. This difference, which persisted even after the correction for the latency variation of MUPM, cannot be explained on the basis of an enhanced reciprocal inhibition. Thus, the increased latency fluctuation of the single motor unit H‐reflex in patients with MND may reflect changes in the motoneuron pool excitability that may be secondary to altered intrinsic electrophysiological properties of motoneurons, or to an abnormal temporal and spatial summation of synaptic inputs on motoneurons.
Distal small fiber neuropathy: Results of tests of sweating and autonomic cardiovascular reflexes
Authors: Stewart John D. , Low Phillip A. , Fealey Robert D. 
Published: January 2005

AbstractThe purpose of this study was to evaluate sweating and cardiovascular autonomic function in patients with distal small fiber neuropathy (DSFN). Sweat testing by the quantitative sudomotor axon reflex test was abnormal in 32 of 40 (80%) patients. The thermoregulatory sweat test was abnormal in 18 of 25 (72%) patients; one or both tests were abnormal in 36 of 40 (90%). Minor heart rate abnormalities were present in 11 of 40 (28%) patients. We conclude that, in patients with DSFN: (a) the sympathetic sudomotor fibers are frequently affected, and that evaluation of sweating is a useful diagnostic test; (b) that the autonomic nerves controlling heart rate are less affected.
Wallerian degeneration in human nerves: Serial electrophysiological studies
Authors: Chaudhry Vinay , Cornblath David R. 
Published: January 2005

AbstractAfter nerve transection, the distal stump undergoes Wallerian degeneration (WD). Little information is available concerning sequential changes in nerve conduction measurements during WD in humans. Five patients with nerve injuries were studied temporally. Motor‐evoked amplitudes were reduced by 50% at 3 to 5 days after injury; the response was absent by day 9. Sensory‐evoked amplitudes were reduced by 50% at 7 days after injury; the response was absent by day 11. Sensory and motor nerves with shorter distal stumps showed earlier loss of amplitude than did those with longer distal stumps. Denervation potentials were seen 10 to 14 days after injury. Our results suggest that WD occurs earlier if the distal stump is shorter, and that motor‐evoked responses are affected earlier than sensory‐evoked responses. The time‐lag between the loss of the motor‐evoked response and the appearance of denervation potentials, the latter coinciding with reduction of sensory evoked responses, suggests that failure of neuromuscular transmission precedes axonal loss during WD.
Diagnostic sensitivity of the laboratory tests in myasthenia gravis
Authors: Oh Shin J. , Kim Doo E. , Kuruoglu R. , Bradley Ronald J. , Dwyer Donard 
Published: January 2005

AbstractThe diagnostic sensitivity of three laboratory tests [serum antiacetylcholine receptor antibody (AChR‐ab) assay, the repetitive nerve stimulation (RNS) test, and, the single fiber EMG (SFEMG)] for myasthenia gravis (MG) was compared in 120 patients. In all cases, at least one of the tests was abnormal. SFEMG was the most sensitive test, being abnormal in 92% of cases, followed by the RNS test (77%) and the AChR‐ab assay (73%). SFEMG was abnormal in all cases with negative ACHR‐ab and RNS tests, in 97% of cases with negative AChR‐ab assay, in 89% of cases with negative RNS test, and in 89% of cases with mild MG. We conclude that one of these three tests is abnormal in all cases of MG, and that the SFEMG is most sensitive in the diagnosis of MG.
Improved medium with EGF and BSA for differentiated human skeletal muscle cells
Authors: St. Clair Judy A. , Meyer‐Demarest Sarah D. , Ham Richard G. 
Published: January 2005

AbstractEpidermal growth factor (EGF) and bovine serum albumin (BSA) are both required for serum‐free clonal growth of human muscle satallite cells (HMSC). However, neither inhibits differentiation of HMSC, and when both are added to a minimal serum‐free differentiation medium, they enhance survival and maintenance of human myotubes. A combination of 10 ng/mL EGF and 0.5 mg/mL BSA, added to MCDB 120 plus 10 μg/mL insulin, increasesboth total protein per dish and total creatine kinase activity, and keeps the myotubes in good condition for a longer period of time. The myotubes become cross‐striated and exhibit frequent spontaneous twitching. Substantial amounts of neonatal myosin heavy chain and the MM isozyme of creatine kinase are expressed, together with detectable amounts of adult fast myosin heavy chain. With regular feeding, these cultures can be maintained for at least 3 weeks with no overgrowth by mononucleate cells, and with far less degeneration than with insulin as the only supplement.