bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrosion studies under conditions of thermal desalination. II. The influence of oxygen content, pH value, flow rate and impurities on the corrosion rates of unalloyed and low alloyed steels
Authors: Heitz E. , Manner R.
Published: December 2004

Corrosion rates determined on the basis of weight loss and polarization resistance are considerably lower for a 6% chromium steel than for an unalloyed steel C 15 (DIN 17210), a base‐melt and a 5.5% Ni steel. The results of a 100 hrs test and a short duration parameter studies at various oxygen concentrations show that above 100°C there is a minimum corrosion rate at 10 ppb oxygen. At oxygen concentrations above 20 ppb there is a transition from uniform corrosion to pitting. The dependence of corrosion rate on pH is in accordance with expectations; the same is true with the dependence on flow rate. Sulphides as impurities in sea‐water become corrosion stimulators only below pH 7, but are highly active even in the ppm range. Addition of 1 ppm copper ions gives rise to considerable stimulation, too. The results obtained in this study enable conclusions to be drawn with respect to the operation of sea‐water desalination plant.
A study of acrylic coatings with dibenzoylmethane for the promotion of Corrosion Protection of Carbon Steel under condensing humidity testing conditions
Authors: Kam T. T. , Hon P. K.
Published: December 2004

The physical adhesion between organic coating film and metallic surface can be enhanced by chemical interactions. This effect is achieved in this work by dibenzoylmethane which is added to an acrylic resin solution for the coating of carbon steel surface, as demonstrated by the formation of the iron complex on the metallic surface and the significant increase in corrosion resistance of the coating film in a condensing humidity test.
Einflüsse von Legierungselementen auf die Korrosion und Wasserstoffaufnahme von Eisen in Schwefelsäure – Teil I: Permeation, Diffusion und Löslichkeit von Wasserstoff in binären Eisenlegierungen
Authors: Riecke Ernst , Johnen Brigitte , Grabke Hans Jürgen
Published: December 2004

Die Einflüsse der in Stählen üblichen Begleit‐ und Legierungselemente C, S, P, Mn, Si, Cr, Ni, Sn und Cu auf die Aufnahme und Permeation von Wasserstoff durch Eisen wurden mit Hilfe der elektrochemischen Permeationsmethode an binären Eisenlegierungen untersucht. Zur Beschreibung des Einflusses der Legierungszusätze auf die Wasserstoffaktivität an der Metalloberfläche sowie den Wasserstofftransport im Volumen wurden der Permeationskoeffizient, der Diffusionskoeffizient und die Löslichkeit des Wasserstoffs für Temperaturen zwischen 10 und 80° C bestimmt.

Die stationäre Wasserstoffpermeation wird allein durch Si und Cr stärker gehemmt. Si erniedrigt vor allem die Löslichkeit des Wasserstoffs in Eisen und hemmt weniger die Diffusion. Cr verursacht im Eisengitter Plätze hoher Bindungsenergie (‐ 58 kJ/mol) für Wasserstoff und erniedrigt damit dessen Beweglichkeit. Die Gesamtwasserstoffkonzentration wird durch Cr erhöht. Permeationsmessungen an handelsüblichen Stählen zeigen vor allem den Si‐Einfluß.
Tantalum as a material of construction for the chemical processing industry – A critical survey
Authors: Gramberg U. , Renner M. , Diekmann H.
Published: December 2004

Materials selection is based on safety and economic considerations; the least expensive material securely withstanding service conditions for a required service time is chosen. For the integrity of equipment in the CPI chemical resistance is an essential factor. Of all metallic materials used for CPI equipment, tantalum is second to none regarding chemical inertness, comparing only to resistance properties of the nonmetals glass, fluoropolymers, and graphite. The price of tantalum, however, prohibits its broad application for construction. There are only two ways by which the demand for tantalum in this field can be promoted significantly. First, a major increase in the aggressivity of service conditions in process engineering caused by process development or modification. Second, cost reduction via tantalum price dilution by means of duplex systems application, utilizing the advantages of a less expensive base metal and a thin tantalum lining or coating. The more important systems of this type are discussed and evaluated regarding their potential of development.
Mechanische Verträglichkeit bei Verbundwerkstoffen – Naßkorrosion
Authors: v. Meysenbug C.‐M.
Published: December 2004

Das Auftreten von Naßkorrosion zwischen den Komponenten eines Verbundwerkstoffs setzt voraus, daß beide Komponenten der umgebenden feuchten Atmosphäre oder einer umgebenden Flüssigkeit zugänglich sind. In diesem Fall kann bei jedem metallischen Verbund ‐ faserig, lamellar oder geschichtet ‐ und unabhängig von der mechanischen Verträglichkeit Kontaktkorrosion ausgelöst werden. Entstehen durch Unverträglichkeit (oder durch äußere Einflüsse) Risse, so kann Spaltkorrosion hinzukommen; und bei Eigenspannungen, wie auch bei äußeren Spannungen, kann Spannungsrißkorrosion beobachtet werden, sofern eine der Komponenten dagegen anfällig ist. Austenitische Stahldrähte z. B. neigen zu SpRK und können damit ihren Verstärkungseffekt einbüßen. Auch die anderen Korrosionsarten, die meist zu Lasten des Matrix‐ oder Grundwerkstoffs gehen, mindern in jedem Fall die Eigenschaften des Verbundes.

Für einige Beispiele heute gebräuchlicher Verbundwerkstoffe werden die möglichen Korrosionsarten tabellarisch zusammengestellt.
Langzeit‐ und Dauerschwingfestigkeit des Vergütungsstahls 25CrMo4 bei mehrachsiger Beanspruchung durch drei schwingende Lastspannungen
Authors: Grün P. , Troost Prof. Dr. ‐Ing. A. , Akin O. , Klubberg F.
Published: December 2004

Vorgestellt werden Ergebnisse aus lastkontrollierten Einstufen‐Schwingversuchen an insgesamt 537 ungekerbten Voll‐ und Hohlzylinderproben, die das Festigkeitsverhalten von 25CrMo4 unter einachsig mittelspannungsabhängiger und mehrachsiger Schwingbeanspruchung mit Phasennachlauf zwischen gleichzeitig angelegten Lastspannungen σx, σy, τxy im Bereich der Langzeitfestigkeit und im Übergangsgebiet zur Dauerschwingfestigkeit (σ‐N‐Charakteristiken) belegen. Das „Duktilitätsverhältnis”︁ τw/σw und die „Mittelspannungssensibilität”︁ p = p (σw, σzSch, Rm) sind verhältnismäßig unabhängig vom Amplitudenausschlag und der Anzahl ertragener Schwingspiele. Die allgemein mit steigender Schwingspielzahl niedriger liegende Ermüdungsgrenze wird im Fall kombinierter Belastung mit bis zu einer halben Lastperiode zueinander phasenverschoben schwingenden Normalspannungen σx, σy zunehmend kritischer gegenüber der synchronen Schwingung; der ermittelte Festigkeitsabfall ist im Langzeitbereich ausgeprägter als für die Dauerfestigkeit, dagegen üben Phasenverschiebungen zwischen Wechseltorsion τxy und Normalspannungen keinen deutlichen Einfluß auf die zeit‐ und dauerfest ertragbaren Lastspannungsamplituden aus.
Mechanism of growth of the open circuit insulating Oxide films on valve metals
Authors: Abd El‐Rahman H. A.
Published: December 2004

The kinetics of growth of the open circuit insulating oxide films on Hf, Ta, Nb, Zr and Al were studies in many salt solutions using potential and capacitance measurements. The effect of salt type and concentration, oxygen concentration, temperature and surface pretreatment on the growth kinetics were also investigated. In all cases, the potential and the reciprocal capacitance were found to increase linearly with logarithm of time. It is assumed that the oxide film grows via the solid state mechanism under the influence of highly enough electric field strength to cause the ionic migration. The field is created as a result of the adsorption of the electrolyte anions onto the metal oxide surface. The estimated field strengths (H ≈︁ 106 V cm−1) are in favour with the proposed mechanism. The results showed also that the growth rate constant is a function of the field strength.
Analysis of the clinical course of non‐Jewish, autosomal dominant torsion dystonia
Authors: Burke Robert E. , Brin Mitchell F. , Fahn Stanley , Bressman Susan B. , Moskowitz Carol
Published: January 2005

We have analyzed the clinical course of non‐Jewish, autosomal dominant torsion dystonia in 41 patients among 15 families. The median age of onset was 8 years, with a range of 0.8–57 years. The body regions most frequently affected at the onset were the legs and arms. There was a relationship between age of onset and site of onset; at earlier ages the legs were more frequently affected, whereas at later ages, the arms and cranial structures were more frequently affected. Fifty‐three percent of patients developed generalized dystonia within a median time of 1 year. Two factors strongly associated with the occurrence of generalized dystonia are: early age of onset, and onset in the legs. Our results are similar to those of prior studies of non‐Jewish and Jewish patients with torsion dystonia. Whether there are clinical distinctions between the Jewish and non‐Jewish forms of dystonia, as proposed in the past, must be reinvestigated in patients within the same referral base.
Do enkephalins in basal ganglia mediate a physiological motor rest mechanism?
Authors: de Ceballos M. L. , Baker M. , Rose S. , Jenner P. , Marsden C. D.
Published: January 2005

Thermal injury (30‐s immersion in water at 62°C) of one hind limb of rats caused a gradual withdrawal of the limb from use, such that after 1 week 50% of the animals walked on three legs. At 24 h following thermal lesion and at a time when the lesioned paw was still used for walking there was a reduction in met‐and leu‐enkephalin content in the periaqueductal grey (PAG) and bilateral reduction in leu‐enkephalin content of the globus pallidus, but no change in enkephalin levels in caudate‐putamen. One week following the lesion, animals exhibiting complete withdrawal of the injured limb, showed bilateral reduction of met‐ and leu‐enkephalin content of PAG. Both met‐ and leu‐enkephalin were bilaterally reduced in globus pallidus as was the met‐enkephalin content in caudate‐putamen. In each case the change was more marked in basal ganglia areas contralateral to the lesion. In animals lesioned 1 week previously and which did not use the injured limb, there was no change in the monoamine (or metabolite) content of caudate‐putamen or in the spontaneous or potassium‐evoked release of 3H‐dopamine from striatal slices. Thermal injury did not cause any general change in pain sensitivity and the time of change in pain threshold in the injured limb did not parallel the withdrawal of the affected limb from walking. The results suggest that after a thermal limb lesion, delayed changes in basal ganglia enkephalin content may be important in withdrawing the injured limb from the normal pattern of locomotion. Basal ganglia enkephalins may be involved in a physiological rest mechanism, which allows healing of the affected part.
Generalized chorea due to basal gnglia lacunar infarcts
Authors: Sethi K. D. , Nichols F. T. , Yaghmai F.
Published: January 2005

Although hemichorea is often ascribed to a vascular lesion, generalized chorea of adult onset is often thought to be due to degenerative diseases. We describe a 74‐year‐old woman with generalized chorea that was diagnosed at autopsy as due to multiple lacunar infarcts in the basal ganglia. Generalized chorea in adults may be caused by vascular disease of the basal ganglia.
The autonomic nervous system in Gilles de la Tourette's syndrome
Authors: Goetz Christopher G. , Shannon Kathleen M. , Carroll V. Susan , Tanner Caroline M. , Weingarten Randall
Published: January 2005

Twenty‐three patients with Gilles de la Tourette's syndromes (GTS) underwent nonivasive investigation of autonomic nervous system (ANS) function, as did 23 age‐matched controls. ANS function in GTS patients was no different from that of controls, and patients receiving neuroleptic drugs had the same ANS function as untreated patients. All 23 patients later received clonidine and were retested. The ANS values before administration of clonidine were compared with those while patients were taking clonidine. The only significant change (p <0.01) with clonidine was a reduced resting pulse rate. The combination of clonidine and neuroleptic drugs did not induce significant autonomic changes compared with neuroleptoc therapy alone. These results indicate that the ANS in GTS patients is normal and that the drugs used to abate tics do not produce clinically significant changes in ANS when chronically given. The findings suggest that the pathophysiology and treatment of GTS do not directly involve the nuclei or tracts of autonomic regulation.
Stability of the head: Studies in normal subjects and in patients with labyrinthine disease, head tremor, and dystonia
Authors: Gresty Michael
Published: January 2005

The dynamics of postural control of the head were investigated in normal human subjects and patients with neurological disease. The technique adopted was to measure the head movements provoked by passive, unpredictable oscillations of the trunk in the frequency range 0–6–7 Hz when subjects were required (a) to try to stabilise their head “in space” and (b) to try to make their heads move “en bloc” with the trunk. Head movement responses were characterised by the gain and phase with respect to trunk movement (transfer function) and degree of linear relationship between head and trunk (coherence). The normal transfer function approximated a cascade of two secondorder, underdamped, systems representing the passive inertial, viscous, and elastic properties of the muscle and joints of the head and neck. Stabilisation of the head “in space” produced about 40% reduction in transmission of body movement, was only evident at frequencies <1 Hz and was affected partly by voluntary movements. An alabyrinthine patient could also achieve some spatial stabilisation. The findings indicate a weak role for vestibular‐collic reflexes and emphasise that the primary control of head posture during unpredictable movement is through the tonic visco‐elastic properties of neck muscles that work to stabilise the head on the shoulders. In patients with dystonia of the nekc and essential and cerebellar head tremor, the dystonia could be measured in terms of visco‐elastic constants and damping ratios. The head movement of some tremor patients did not linearly follow the trunk movement, showing that the motion stimulus provoked abnormal phasic muscle activity at frequencies other than those of the tremor. The technique quantifies head control in movement disorders and is sensitive to abnormal function.
Corneal and blink reflexes in Parkinson's disease with “on‐off” fluctuations
Authors: Agostino R. , Berardelli A. , Cruccu G. , Stocchi F. , Manfredi M.
Published: January 2005

In 13 patients with Parkinson's disease and “on‐off” fluctuations and in a control group, the electrically evoked blink (R1 and R2 component) and corneal reflexes (CR), the habituation of the glabellar reflex, and the blink rate were studied. Latency, amplitude, and recovery cycle of R1 was normal. CR latency, but not R2 latency, was significantly shorter in patients than in normal subjects. R2 recovery cycle, but not CR recovery cycle, was facilitated in “off” patients in comparison to normal subjects. CR and R2 duration was longer in “off” than in “on” patients. R2 recovery cycle became similar to that of normal subjects after fluctuation from “off” to “on” period, but CR recovery cycle varied only slightly. The habituation of the glabellar reflex and the blink rate were decreased in “off” patients. These findings indicate that the enhanced excitability of R2 is related to the central dopamine activity levels. The differences between the recovery cycles of CR and R2 may be explained with the smaller number of interneurons subserving CR than R2 circuit. The shorter latency of CR, but not of R2, both in “on” and “off” patients, may suggest that in Parkinson's disease basal ganglia exert a different control of incoming sensory input transmitted via beta and delta fibers.
Tardive myoclonusa
Authors: Little John T. , Jankovic Joseph
Published: January 2005

We describe a 46‐year‐old, schizophrenic woman with late‐onset myoclonus after treatment with antipsychotic drugs. The myoclonic jerking of the neck with synchronous contractions of the face persisted after all the antipsychotic drugs had been discontinued. Tardive myoclonus has not been documented previously.
Analysis of open‐label trials in torsion dystonia using high dosages of anticholinergics and other drugs
Authors: Greene Paul , Shale Heidi , Fahn Stanley
Published: January 2005

We reviewed the records of 358 patients with various forms of focal, segmental, and generalized dystonia who had received pharmacotherapy in a systematic order, beginning with anticholinergics. If no benefit was encountered, we then tested clonazepam, baclofen, and other agents sequentially. In each situation the dosage was gradually increased until benefit or troublesome adverse effects were encountered. In this manner we obtained data on the percentage of patients who showed moderate to marked benefit. Anticholinergics were the most beneficial agent, confirming previous reports. Statistical analysis of this response revealed that benefit from anticholinergics was most likely if treatment was begun within 5 years after the onset of dystonia. From this analysis, it appears that delaying treatment beyond 5 years is likely to result in an unsatisfactory response.
Hemiballism in multiple sclerosis
Authors: Riley David , Lang Anthony E.
Published: January 2005

Hemiballism has rarely been reported in the setting of multiple sclerosis. Review of clinical descriptions cast some doubt on the accuracy of the diagnosis of the movement disorder in several previous cases. We report a patient with definite multiple sclerosis, with videotape documentation of hemiballism, and demonstration of a plaque in the contralateral subthalamic nucleus on a magnetic resonance image.
Movement disorders in multiple sclerosis
Authors: Mao Chi‐Chen , Gancher Stephen T. , Herndon Robert M.
Published: January 2005

Movement disorders other than cerebellar tremor are rare clinical manifestations of multiple sclerosis (MS). Two cases of parkinsonism and a case of chorea associated with MS are reported, and the literature is reviewed.
The first agonist and antagonist burst in patients with an upper motor neuron syndrome
Authors: Fagioli S. , Berardelli A. , Hallett M. , Accornero N. , Manfredi M.
Published: January 2005

Rapid elbow flexion movements were studied in patients with an upper motor neuron syndrome following a stroke. The velocity of movements was slower than normal. The initial bursts of electromyographic (EMG) activity in both the agonist and antagonist muscles were prolonged. As in normal subjects, the first agonist burst increased in duration with larger movements, but it generally remained about 40 ms longer than normal. The size of the first agonist burst also increased with larger movements. A fixed linkage between burst duration and level of motor unit recruitment, together with a deficient corticospinal command, could explain the prolonged burst duration with preserved ability to modulate the burst.
Lower body parkinsonism: Evidence for vascular etiology
Authors: Fitzgerald Patricia M. , Jankovic Joseph
Published: January 2005

We studied 10 patients with marked gait difficulty and no or only minimal upper limb involvement, defined here as lower body parkinsonism (LBP). They were compared to a control group of 100 patients with otherwise typical Parkinson's disease (PD). Both groups were of comparable age, but the mean duration of symptoms was significantly shorter in the LBP group (2.6 ± 1.5 years versus 7.5 ± 4.9 years). Gait disturbance was the initial symptom in 90% of LBP patients, as opposed to 7% of controls. Hypertension was present in 70% of LBP patients, and only 22% responded to levodopa. In contrast, only 21% of controls had a history of hypertension, and 96% improved with levodopa. We conclude that these 10 LBP patients constitute a homogenous group, distinct from typical PD. Besides their disproportionate gait disturbance, they are distinguished from PD patients by more rapid progression, higher incidence of hypertension, and a poor response to levodopa. Ischemic etiology for LBP is supported by abnormal neuroimaging studies.
Hemichorea‐hemiballismus associated with acquired immune deficiency syndrome and cerebral toxoplasmosis
Authors: Sanchez‐Ramos Juan R. , Factor Stewart A. , Weiner William J. , Marquez Jose
Published: January 2005

A young woman had hemichorea‐hemiballismus subsequently found to be secondary to a cerebral toxoplasmosis infection complicating human immunodeficiency virus infection. This patient had the sixth reported case of acquired immune deficiency syndrome (AIDS) with hemichorea‐hemiballismus, and each has been secondary to cerebral toxoplasmosis. The presence of hemichorea‐hemiballismus in a young patient should suggest a diagnosis of AIDS and in particular the diagnosis of secondary cerebral toxoplasmosis. Other movement disorders that occur in AIDS are discussed.
Spasms of amputation stumps: A report of 2 cases
Authors: Marion M. H. , Gledhill R. F. , Thompson P. D.
Published: January 2005

The occurrence of involuntary movements of stumps follwing amputation is described in two patients. Although recognised for over 100 years, this phenomenon has received little attention in the modern literature. The condition appears to represent a variant within the spectrum of movement disorders induced by injury to the peripheral nervous system.
Complex hyperkinesia during recovery from left temporoparietal cortical infarction
Authors: Ferbert A. , Rickert H. B. , Biniek R. , Brückmann H.
Published: January 2005

A 51‐year‐old man with preexistant lacunar infarctions in the basal ganglia and pons developed complex involuntary movements of his right arm 1 day after a purely cortical‐subcortical ischemic infarction in the territory of the left middle cerebral artery sparing the basal ganglia. The movements were stereotyped and repetitive, affecting hand and fingers or proximal arm muscles alternatively or together. Although hyperkinesia after basal ganglia lesion has been described many times in the literature, it has not yet been reported after cortical‐subcortical ischemic infarctions sparing the basal ganglia.
Dystonic tics in patients with Tourette's syndrome
Authors: Jankovic Joseph , Stone Lael
Published: January 2005

Dystonic tics, in contrast to clonic tics, are relatively slow and temporarily sustained twisting, pulling, or squeezing movements producing briefly maintained abnormal postures. Because dystonic tics often present diagnostic difficulties, we studied these motor tics in 156 patients with Tourette's syndrome (TS). In addition to clonic motor and vocal/phonic tics, seen in all patients, 89 (57%) of them exhibited one or more dystonic tics. The most common dystonic tics were oculogyric deviations (43 patients), blepharospasm (23), and dystonic neck movements (11). Blinking (110) and facial twitching (86) were the most common clonic tics. Except for possibly a greater familial occurrence, a higher frequency of previous head trauma, and associated attention deficit disorder, the group of patients with dystonic tics did not significantly differ in any of the major clinical variables from those TS patients without dystonic tics. We conclude that dystonic tics are typical motor manifestations of TS and that patients with these motor tics are not different from those with more typical clonic tics.
Muscle relaxation in Parkinson's disease: A reaction time study
Authors: Grasso M. , Mazzini L. , Schieppati M.
Published: January 2005

We tested the hypothesis that the relaxation reaction time in Parkinson's disease (PD) is delayed, as a sign of disorder in the control of voluntary motoneuron derecruitment. We compared, in the triceps brachii muscle, the reaction times (RTs) of the onset (O‐RT) of electromyographic (EMG) activity during initation of a contraction with the RTs of the termination of EMG tonic activity during full relaxation (R‐RTs). Fourteen patients with idiopathic PD and 10 normal controls were examined. Mean R‐RTs for all controls were 30 ms shorter than mean O‐RTs. Mean R‐RTs for all patients were ∼70 ms longer than mean O‐RTs. In two untreated patients levodopa therapy improved both O‐RT and R‐RT, but the difference between the two was unchanged. There was no correlation between EMG level and R‐RT or between peak force and O‐RT in either controls or patients. O‐RT and R‐RT were correlated with the bradykinesia score. In some patients, bursts of late activity were recorded after the R‐RT; the duration of this activity was correlated with the duration and staging of the disease and with bradykinesia and rigidity scores. The reversed latency of onset and termination of muscle contraction in PD suggests an abnormality in the inhibitory spinal mechanisms, possibly stemming from a defect in the pathways descending to the spinal cord.
Autosomal dominant “spheroid body myopathy”
Authors: Goebel Hans H. , Muller Jans , Gillen H. William , Merritt A. Donald
Published: January 2005

A slowly progressive autosomal dominant neuromuscular disease–termed spheroid body myopathy–is described in four successive generations and documented by muscle biopsies in five patients of two generations. With an onset in adolescence, the disease proceeds to some motor incapacitation, but life span is apparently not shortened. The salient morphologic feature is the presence of spheroid bodies, chiefly occurring in type 1 myofibers. Ultrastructurally, these spheroid bodies are composed of fine filaments but are devoid of organelles; in some cases they resemble cytoplasmic bodies. “Smearing in the l‐band” is a frequent and early finding. At a later age, signs of denervation are also present, both clinically and in muscle biopsies. The clinical and morphologic features justify the designation of this neuromuscular condition as a distinct entity.
F‐wave conduction velocity in the deep peroneal nerve: Charcot‐marie‐tooth disease and dystrophia myotonica
Authors: Panayiotopoulos Chrysostomos P.
Published: January 2005

The F‐wave has been used to estimate the motor nerve conduction velocity (MNCV) along the proximal segment (spinal cord to knee) of the axons of the deep peroneal nerve in patients with Charcot‐Marie‐Tooth disease and those with dystrophia myotonica. A new, modified method has been applied to estimate proximal MNCV in patients in whom F‐waves or M‐responses cannot be obtained from the small muscles of the foot. Terminal latencies and MNCV along the distal nerve segment (knee to ankle) have also been estimated using conventional techniques. The results have been compared with those obtained for control subjects. Proximal MNCV was severely slowed in every patient with Charcot‐Marie‐Tooth disease; the degrees of proximal and distal MNCV decreases were related. In patients with dystrophia myotonica, distal and proximal MNCVs were significantly reduced in comparison with control subjects; the MNCV slowing was not related to the degree of muscle atrophy. This is consistent with the hypothesis that the nerves and muscles are independently affected in dystrophia myotonica. It is concluded that the F‐wave MNCV technique is as useful as, and may be more sensitive than, the conventional MNCV method.
Neonatal experimental autoimmune myasthenia gravis
Authors: Sanders Donald B. , Cobb Edith E. , Winfield John B.
Published: January 2005

Neonatal rats born of and nursed by mothers immunized with Torpedo acetylcholine receptor protein developed a defect of neuromuscular transmission as indicated by reduced miniature endplate potential amplitudes. It is likely that antibodies to the Torpedo receptor protein were passively transferred to the neonates in the milk. With the exception of the route of transfer, this neonatal from of experimental autoimmune myasthenia gravis appears to be similar to its human counterpart, and thus can serve as an experimental model.
Acute muscle necrosis after chronic overdosage of phenformin and fenfluramine
Authors: Palmucci L. , Bertolotto A. , Schiffer D.
Published: January 2005

A case of acute muscle necrosis with probable myoglobinuria is presented. The patient had been taking excessive doses of phenformin and fenfluramine, and a toxic etiology is suggested. Muscle necrosis is tentatively attributed either to the combined effect of these drugs on some underlying biochemical abnormality of muscle or to a defect of oxygen utilization secondary to myoglobin alterations.
Thenar hypoplasia with associated radiologic abnormalities
Authors: Cavanagh N. P. C. , Yates D. A. H. , Sutcliffe J.
Published: January 2005

We report on five patients who presented with unilateral or bilateral hypoplasia of the thenar eminence. X rays of the affected limbs showed varying degrees of malformation and underdevelopment of the thumb phalanges and first metacarpal bone, and of the carpal bones at the base of the thumb, indicating a developmental abnormality. Our electrodiagnostic findings were compatible with this interpretation. We suggest that this condition is part of the clinical spectrum of radial club hand (radial dysplasia) and that when seen in adults, its recognition is important in the differential diagnosis of carpal tunnel syndrome.
Actomyosin ATPase. I. Quantitative measurement of activity in cryostat sections
Authors: Mabuchi K. , Sréter F. A.
Published: January 2005

A method for the quantitative study of the actomyosin ATPase activity (Ca, MG‐ATPase) in thin sections cut in a cryostat is presented. This method is based on the liberation of 32P from [γ32P]ATP or 45Ca phosphate precipitation. The advantage of this method lies in the requirement for only a small muscle sample and the availability of serially cut sections for other assays including Ca uptake by sarcoplasmic reticulum and histochemical tests for oxidative and glycolytic enzymes. The actomyosin ATPase activity for various types of muscles determined by this method showed the same sequence found in isolated protein, that is, fast‐twitch skeletal > slow‐twitch skeletal > cardiac. The Ca, Mg‐ATPase of cryostat sections showed Ca sensitivity. The fact that the sections retained Ca sensitivity at 37°C, in contrast to myofibrils, which have been reported to lose Ca sensitivity at this temperature, indicates that the structural integrity of the contractile and regulatory apparatus is preserved to a higher degree in sections than in isolated myofibrils.
Microanalysis of perineural calcification in diabetic nephropathy
Authors: Kalimo Hannu , Mäki Jouko , Paetau Anders , Haltia Matti
Published: January 2005

Three different microanalytical methods were used to identify calcium deposits in the sciatic nerve perineurium of a 33‐year‐old woman who died after developing nephropathy, retinopathy, and neuropathy as complications of diabetes. Scanning electron microscopic x‐ray microanalysis (SEM‐XMA) enabled localization of calcium and phosphorus elements to the perineurium in whole nerve cross sections. With SEM‐XMA and scanning‐transmission electron microscopic x‐ray microanalysis (STEM‐XMA) of the minute crystallites in the perineurium, the approximate relative amounts of calcium and phosphorus in the deposits were found to correspond to those in calcium hydroxyapatite. Finally, the crystallites were specifically identified by selected area electron diffraction, and were found to be composed mainly of calcium hydroxyapatite.
Neuron specific in vitro cytotoxicity of sera from patients with amyotrophic lateral sclerosis
Authors: Roisen Fred J. , Bartfeld Harry , Donnenfeld Hyman , Baxter Janet
Published: January 2005

Sera from patients with amyotrophic lateral sclerosis (ALS) were assayed for a neuron‐specific cytotoxic effect on long‐term organized cultures of neonatal mouse anterior horn segments. Blind studies show that ALS sera when incorporated into the culture media have a greater degree of antineuronal toxicity than sera from patients with other neurological diseases or from family members of ALS patients.
Regeneration of peripheral nerve through a polyglactin tube
Authors: Molander Hårkan , Olsson Yngve , Engkvist Ove , Bowald Staffan , Eriksson Ingvar
Published: January 2005

Polyglactin 910, a resorbable synthetic material, was used as a mesh‐tube to bridge defects (7 to 9 mm in length) in sectioned rabbit tibial nerve. After absorption of the mesh a new nerve sheath was formed which enclosed numerous minute fascicles of regenerating axons. The polyglactin tube influenced the direction taken by the regenerating axons and guided them into the distal segment. The tube also reduced the formation of neuromas and the growth of scar tissue from surrounding structures.
Exercise effects on recovery of muscle acetylcholinesterase from reduced neuromuscular activity
Authors: Gardiner Phillip F. , Lapointe Mario , Gravel Diane
Published: January 2005

In order to investigate the effects of reduced and subsequently increased neuromuscular activity on muscle acetylcholinesterase (AChE), rats had one hindlimb immobilized with plaster casts for 4 weeks and were killed either at the end of immobilization (group I), after 4 weeks of resumed normal activity following cast removal (group R), or after 4 weeks of resumed activity supplemented with a daily treadmill‐walking task (group E). Immobilization resulted in a decrease in adductor longus muscle weight to 66.4% of control; total muscle end‐plate‐associated AChE was decreased to 51.4%. Total muscle ACh hydrolysis was not significantly affected. Mild daily exercise during recovery increased total muscle end‐plate AChE to control levels after 4 weeks, while in group R the corresponding level was significantly lower (84.4%). Decreased neuromuscular activity has different effects on end‐plate AChE and non‐end‐plate AChE. Mild endurance‐type overload during recovery from immobilization can accelerate recovery of end‐plate AChE activity to normal.
Chronic denervation of rat diaphragm: Selective maintenance of adult fast myosin heavy chains
Authors: Carraro Ugo , Libera Luciano Dalla , Catani Claudia , Danieli‐Betto Daniela
Published: January 2005

After long‐term denervation in mixed rat muscles there is a selective loss of slow myosin. The bidimensional electrophoretic pattern of light chains and the results of preliminary studies on heavy chains have left open the question of whether the nature of the residual fast‐like myosin is of the immature or adult type. We have further investigated chronically denervated myosin by (1) electrophoresis in nondissociating conditions; (2) acidic electrophoresis of the heavy chains; and (3) proteolytic mapping of the heavy chains. These techniques clearly distinguish adult myosins from those present in immature muscles. Using these criteria, myosin from the chronically denervated diaphragm is of an adult type, even though the presence of trace amounts of embryonic myosin cannot be excluded. The contractile properties also indicate that chronically denervated hemidiaphragm is more similar to an adult fast muscle than to an immature muscle. The selective maintenance after long‐term denervation of fast myosin in adult muscle provides good evidence of the independence of the genetic expression of myosin from a direct neural chemotrophic control.
Motor and sensory neurons of the rat sural nerve: A horseradish peroxidase study
Authors: Peyronnard Jean‐Marie , Charron Louise
Published: January 2005

Neurons of origin of the rat sural nerve were labelled with horseradish peroxidase. Dorsal root ganglionic cells were located in the L4 and L5 ganglia, and occasionally at the L6 level. Most of these sensory neurons measured under 35 μm in diameter. In keeping with previous electrophysiological studies suggesting the presence of motor fibers to plantar muscles in the rat sural nerve, motoneurons were identified at the caudal end of the L5 spinal segment, intermingled in the posterior aspect of the ventral horn with posterior tibial motor cells supplying the foot muscles. A quantitative analysis of HRP‐labelled motoneurons revealed no difference between normal (average 67) and deafferented animals (average 70), the values being only marginally lower than counts of motor axons in deafferented sural nerves (average 80).
Antagonism of botulinum toxin paralysis by low temperature
Authors: Lundh Håkan
Published: January 2005

Decreasing the temperature from 37 C to 20 C in vitro reactivates muscle twitch in response to nerve stimulation in a muscle previously paralyzed by botulinum toxin. Transmitter release calculated as quantum content of endplate potentials has an extremely enhanced sensitivity to temperature in botulinum paralysis (Q10 about 45) compared to normal muscle blocked by high magnesium concentration (Q10 about 2). This difference is not caused by increased efficacy of the calcium mechanism of transmitter release in botulinum poisoning at low temperature, as demonstrated by unaltered calcium‐dependence of quantum content at 22 C compared to 35 C for both types of neuromuscular block. The results give exciting clues to the mode of action of botulinum toxin.
Reinnervation in duchenne muscular dystrophy
Authors: Dubrovsky Alberto , Taratuto Ana Lía
Published: January 2005

Motor neuron abnormalities have been implicated in the pathogenesis of Duchenne muscular dystrophy. Evidence concerning the effect of injury on motor neurons of human Duchenne muscular dystrophy (DMD) is lacking. We report a DMD patient having, in addition, an obstetric paresis on his left arm. EMG and muscle histochemistry showed signs of reinnervation superimposed on myopathy in his left arm. This suggests that sprouting is preserved in DMD motor neurons and that muscle fibers retain the capability of accepting reinnervation.
Recombinant DNA strategies in genetic neurological diseases
Authors: Roses Allen D. , Pericak‐Vance Margaret A. , Yamaoka Larry H. , Stubblefield Elton , Stajich Jeffery , Vance Jeffery M. , Roses Marcia J. , Carter Donald B.
Published: January 2005

The application of recombinant DNA techniques applied to the study of genetic neurological diseases will play a major role in the practice of neurology in upcoming years. Strategies are now available to develop useful and relatively simple biochemical diagnostic tests for heterozygous individuals with diseases inherited as autosomal dominant traits. In addition, molecular genetic methods will lead to the delineation of the genomic mutations responsible for these diseases. This review will update the current status of research in several neurological genetic diseases including myotonic muscular dystrophy, Huntington's disease, Charcot‐Marie‐Tooth disease and Duchenne muscular dystrophy (X‐linked). An introduction and overview of the methodology is provided. Specific research strategies including random screening of libraries, chromosome walking, messenger RNA selection, and messenger RNA translation are described. These strategies are designed to provide heterozygote identification, prenatal diagnosis and gestational management, the development of rational therapies, and the understanding of the molecular basis of disease expression.
Presynaptic and postsynaptic actions of procainamide on neuromuscular transmission
Authors: Lee David C. , Kim Yong I. , Liu Humphrey H. , Johns T. R.
Published: January 2005

Procainamide (PA), a cardiac anti‐arrhythmic agent, was applied in vitro to the rat neuromuscular junction and its effect on neuromuscular transmission was investigated using intracellular microelectrode recording techniques. Clinically relevant doses of PA produced a dosedependent decrease in the amplitude of spontaneous miniature endplate potentials (MEPPs) and a marked increase in the half‐decay time without altering MEPP frequency or resting membrane potential. The amplitude of impulse‐evoked end‐plate potentials was also reduced in a similar dose‐dependent manner, with a marked prolongation of the decaying phase. Direct quantal analysis using magnesium‐blocked preparations showed that the drug also caused a reduction in the mean number of acetylcholine quanta released per nerve impulse. This presynaptic inhibitory effect of the drug, however, contributed less to the overall blocking action than did the postsynaptic effect. The junctional effects of the drug were completely reversible, with all affected parameters returning to the control levels after washout of PA with control solution. These direct inhibitory actions on neuromuscular transmission could account for the clinical exacerbations associated with the administration of PA to patients with myasthenia gravis and other neuromuscular diseases.
Increases in myofibrillar ATPase intermediate human skeletal muscle fibers in response to endurance training
Authors: Schantz Peter , Henriksson Jan
Published: January 2005

The response of human muscle triceps brachii (TB) to training, which consisted of skiing with sledges 500 miles over a period of 36 days, has been investigated by means of histochemical fiber typing (myofibrillar ATPase, n = 7). Muscle biopsies were taken in the right TB during pretraining, and in the right as well as in the left TB after training. The percentage of type 2 fibers and intermediate fibers (type 2C and 1B) in the right TB decreased and increased, respectively, by 13%. The fiber type distribution in the left TB after training was very similar to that in the right TB after training. This concordance indicates that the change in fiber type distribution was a result of the training per se, and not related to any eventual effect of the biopsy‐sampling.
Changes in fiber type composition in growing muscle as a result of dynamic exercise and static overload
Authors: Watt P. W. , Goldspink G. , Ward P. S.
Published: January 2005

The effects of dynamic exercise (jumping) and static overload (synergist tenotomy) on rat soleus muscle were investigated during a growing phase in juvenile animals. The relative proportions of slow twitch (type 1), fast twitch (type 2a) and intermediate (type 2c) fibers were determined histochemically. The control animals, as part developmental process, lost type 2a fibers apparently by conversion to type 1 fibers via the type 2c form. Synergist tenotomy enhanced the conversion of type 2a fibers to type 2c fibers as these muscles displayed fewer type 2a fibers than control animals at the same age. In contrast, the dynamic exercise delayed the loss of type 2a fibers from the soleus. When the two exercises were combined the effects on fiber type proportions cancelled each other; this group also had a large number of type 2c fibers. This present study indicates that the activity imposed on a muscle influences the maturational development of the constituent fiber types.
The resting membrane parameters of human intercostal muscle at low, normal, and high extracellular potassium
Authors: Kwieciński Hubert , Lehmann‐Horn Frank , Rüdel Reinhardt
Published: January 2005

Membrane parameters at the respective resting potentials in low, normal, and high extracellular potassium solutions were determined in intercostal muscle fibers from 15 patients with no known neuromuscular disease. In synthetic interstitial fluid (normal potassium concentration 3.5 mmol/liter), we found the following mean values: resting membrane potential RP = ‐−83.3 mV, space constant γLD = 2364 μm, fiber diameter d = 49.3 μm, fiber input resistance Rin = 795 KΩ, specific membrane capacitance Cm = 4.7 μF/cm2, and specific membrane resistance Rm = 5970 Ω·cm2. The specific membrane conductance was gm = 168 m̈S/cm2, 76% of it being chloride conductance, 24% being potassium conductance. The dependence of the membrane parameters on the extracellular potassium concentration followed the predictions by the constant field theory. There was no indication of active chloride transport. The resting membrane conductance decreased with temperature with a Q10 of 1.3. Excitability parameters were nearly independent of temperature between 37 and 27°C.
Drugs in muscular dystrophy of the chicken: Corticosterone ‐21‐acetate
Authors: Entrikin Richard K. , Patterson Gary T. , Wilson Barry W.
Published: January 2005

In a previous series of 22‐day evaluations of 31 compounds, only corticosterone‐21‐acetate (C‐21‐A) increased righting ability of genetically dystrophic chickens to a greater extent than the standard of comparison, methysergide maleate. In the present study, C‐21‐A was subjected to longer‐term trials of up to 48 days, and additional signs of the myopathy were examined. The highest doses of C‐21‐A increased righting ability for the duration of the trials, decreased the typically elevated plasma levels of creatine kinase (CK) activity by more than 80%, and improved morphology of the dystrophic pectoralis major muscle at the light microscopic level. The major adverse effect of C‐21‐A, reduction of body weight, was consistently observed at the relatively high doses needed to increase righting ability. That alone, however, could not account for increased righting ability, and plasma CK activity was decreased even at doses that did not reduce body weight. The results show that C‐21‐A is the most effective compound yet tested in this system and, perhaps more significantly, provides the first evidence that it is possible to identify compounds that improve muscle morphology in a hereditary myopathy using a short‐term, step‐wise system.
Isomyosin distribution in skeletal muscles of normal and myotonic goats
Authors: Martin Anne F. , Bryant Shirley H. , Mandel Frederic
Published: January 2005

Isoforms of myosin were examined in hindleg muscles isolated from normal and myotonic goats. The muscles studied were the soleus, gastrocnemius, gluteus accessorius, semitendinosus, semimembranosus, and adductor. The isomyosins were analyzed by pyrophosphate polyacrylamide gel electrophoresis. The relative proportions of slow and fast myosin isoforms present were determined by densitometric scanning of Coomassie Blue‐stained gels. All muscles contained three fast myosin isoforms and either one or two slow myosin isoforms. In normal goat, the soleus and gastrocnemius, containing 70%–75% slow isomyosins, were representative of slow muscle. The semimembranosus, the semitendinosus, and the adductor, with more than 50% fast myosin, represented a predominantly fast muscle group. The gluteus accessorius, with approximately 45% fast myosin isoforms, was intermediate between the other two groups. In the myotonic goat, a consistent and significant increase in the proportion of fast isomyosins was observed for all the muscles studied. The largest change occurred in the gastrocnemius where the incremental increase in the percentage of fast isomyosins was over 30%. All the other muscles examined had incremental increases in fast isomyosin content which ranged from 16.1% to 22.0%. These results suggest that the abnormal action potential pattern of myotonia leads to a redistribution of the myosin isoforms.
Changes in terminal sprout formation in rat sternocostalis muscle during chronic intoxication with 2,5 hexanedione
Authors: Simonati Alessandro , Cavanagh John B.
Published: January 2005

Qualitative and quantitative morphological studies of the sternocostalis muscle innervation were made on rats chronically intoxicated with 2,5 hexanedione (2,5 HD) using the zinc iodide‐osmium (ZIO) technique. Two distinct phases were seen in the events at the motor endplate. First, the number of motor endplates forming spontaneous terminal sprouts was found to increase linearly with time and, from the third week onward, the sprouts appeared to become progressively elongated. This latter change was associated with the appearance of swollen axons wihtin intramuscular nerve bundles. Second, from the sixth week onward, wallerian degeneration of nerve fibers was seen and terminal sprouts began to make new arborizations on muscle fibers. By the eighth week, this occurred in as many as 66% of the rats, and collateral sprouting was also observed at this time. The occurrence of increased spontaneous terminal sprouting due to altered neuromuscular function is discussed in the light of axonal changes resulting from nerofilament accumulation following 2,5 HD intoxication.