bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of antibodies to identify satellite cells with a light microscope
Authors: Zhang Ming , McLennan Ian S.
Published: January 2005

Satellite cells are essential for the growth and regeneration of skeletal muscles but the study of them has been difficult due to the need to use an electron microscope. This article describes a method which enables satellite cells to be identified with a light microscope. Satellite cells were distinguished from: (1) myonuclei on the basis of whether the nuclei were inside or outside the plasmalemma of a fiber (stained with antidystrophin) and (2) interstitial cells depending on whether they were inside or outside of a fiber's basal lamina (stained with anticollagen IV). Some satellite cells were stained by the antidystrophin which further aided their identification. The question of whether all satellite cells are myogenic has been investigated and discussed. This method will facilitate the study of satellite cells in biopsies of human muscles and the estimation of satellite cell number in laboratory animals. © 1994 John Wiley & Sons, Inc.
Nerve conduction and biopsy correlation in over 100 consecutive patients with suspected polyneuropathy
Authors: Logician Eric L. , Kelly John J. , Adelman Lester S.
Published: January 2005

Neuropathy was classified physiologically and histologically as normal, axonal, demyelinative, or indeterminate using specific motor nerve conduction (NC) and sural sensory nerve biopsy (NB) criteria. Physiological and histological diagnoses were concordant in 63%, and minimally discordant in 14% of patients. The most important discordant patients were 6 with demyelinative neuropathy, 4 by NC, of which 2 were pure motor syndromes, and 2 by NB, both predominantly sensory syndromes. In the 55 patients with predominant axonal degeneration on biopsy, the extent of NC slowing was determined. As compound motor and sensory nerve action potential (CMAP and SNAP) amplitude declined, distal motor latency increased, whereas motor and sensory conduction velocity (CV) did not. Minimum F response latency increased as motor CV decreased, more in lower than upper extremity nerves. We conclude that: (1) except for sensory neuropathy, routine motor NC studies generally suffice in identifying demyelinative neuropathy; (2) NC slowing in axonal neuropathy is usually slight but may result in significantly prolonged distal motor latencies when CMAP amplitude is very low, and prolonged F wave latency when motor CV is slightly low; and (3) The physiologic criteria employed in this study rarely misclassifies neuropathy as demyelinative in patients with predominant axon loss on biopsy. © 1994 John Wiley & Sons, Inc.
Isometric contractile function following nerve grafting: A study of graft storage
Authors: Evans Peter J. , Awerbuck David C. , Mackinnon Susan E. , Wade Judith A. , McKee Nancy H.
Published: January 2005

In order to assess the effects of storage on nerve grafts, the isometric contractile function of the gastrocnemius muscle was assessed 14 months following sciatic nerve autografting in the rat. Three‐centimeter sciatic nerve grafts were stored at either 5°C or 22°C for 6 h, 24 h, or 3 weeks in an organ transplant solution. Muscle mass and maximal force in the fresh control graft group returned to 47% and 36% of normal levels, respectively, which was similar to stored grafts. Storage at 5°C was superior to 22°C and there was no decrement in contractile function in grafts stored up to 3 weeks at 5°C. These findings suggest that the storage of nerve grafts is a feasible technique that might be applied to nerve allografts, thus permitting elective reconstruction of large peripheral nerve gaps. © 1994 John Wiley & Sons, Inc.
Level of independence of motor unit properties from neuromuscular activity
Authors: Pierotti David J. , Roy Roland R. , Hodgson John A. , Edgerton V. Reggie
Published: January 2005

Neuromuscular activity was eliminated in the tibialis anterior muscle of adult cats for 6 months by spinal isolation (Sl), i.e., complete spinal cord transections at T‐12–13 and at L‐7–S‐1, plus bilateral dorsal rhizotomy between the two transection sites. One motor unit from each muscle was isolated using ventral root teasing procedures and physiologically tested. The fibers belonging to each motor unit were visualized in PAS‐staired sections by the loss of glycogen following prolonged repetitive stimulation. Qualitatively, the normal enzymatic interrelationships among fibers identified by myosin heavy chain composition were unchanged by SI. Generally, each motor unit from SI cats were of a single myosin immunohistochemical type. The same physiological motor unit types that typify control muscles were found in SI cats. In Sl compared to control cats, there was approximately a 10% increase in the number of muscle fibers expressing fast myosin. Mean fiber activity levels of ATPase and SDH for a given fiber type (based on MHC antibody reactions) decreased by approximately 10% and 25%, whereas GPD activity increased approximately 35%. It is concluded that differential levels or patterns of activity are not essential to maintain the range of histochemical and physiological motor unit types found in the tibialis anterior of normal adult cats. © 1994 John Wiley & Sons, Inc.
Lymphocyte infiltration following allo‐and xenomyoblast transplantation in mdx mice
Authors: Asselin Isabelle , Vilquin Jean Thomas , Tremblay Jacques P. , Guérette Benoǐt , Roy Raynald
Published: January 2005

Human and mouse (C57BL/10SnJ+/+) myoblasts were injected separately in the muscles of C57BL/10SnJ mdx/mdx mice. Mouse myoblasts (C57BL/10SnJ+/+) were also injected in normal mice (C57BL/10SnJ+/+ and BALB/c +/+). Some muscles that received a xenotransplantation (i.e., human myoblasts) were previously injected with a myotoxin, i.e., notexin. This treatment was not used for the allografts (i.e., mouse myoblasts). Human myoblast injections did not increase the number of dystrophin‐positive cells above the background level due to backmutation. Moreover, the human myoblasts detected with an anti‐HLA antibody decreased rapidly during the 6‐week followup. The injection of normal mouse myoblasts in mdx mice did, however, increase the number of dystrophin‐positive fibers. Moreover, numerous cells expressing mouse MHC class II, macrophages, granulocytes, neutrophils, natural killer cells, and a subset of T lymphocytes were detected by immunohistochemistry in cryostat sections of myoblast injected muscles. These cells were present within 1 week of the myoblast injection in the muscle regions containing injected human or mouse myoblasts, and progressively decreased during the 6‐week follow‐up in the human myoblast transplantation. Lymphocyte infiltration reached a significant level following xeno‐ and alloincompatible transplantations. Antibodies against the human myoblasts and against alloincompatible myoblasts were also detected in the serum of the recipients. These results suggest that humoral and cellular immune reactions are responsible for the poor outcome of myoblast transplantation in mice and could be involved in failure of transplantation in Duchenne muscular dystrophy patients. These results indicate that adequate immunousuppression must be used in these patients.© 1995 John Wiley &Sons, Inc.
Monoclonal antibodies against ICAM‐1 and LFA‐1 prolong nerve allograft survival
Authors: Nakao Yasushi , Mackinnon Susan E. , Hertl M. Catherine , Hunter Daniel A. , Mohanakumar T. , Miyasaka Masayuki
Published: January 2005

In a rat nerve allograft model, specific immunosuppression was approached with monoclonal antibodies (MAbs) against cell‐surface molecules. After engraftment, recipients were treated with antiintercellular adhesion molecule‐1 (ICAM‐1) and antilymphocyte function‐associated antigen‐1 (LFA‐1) MAbs for 14 days. Functional recovery was evaluated biweekly. Electrophysiological and histological assessments were performed at 6 and 16 weeks. Immunologic responsiveness in the recipients was assessed with a cytotoxic T lymphocyte (CTL) assay at 16 weeks and skin grafts at 18 weeks. The untreated allograft group demonstrated complete disruption of fascicular architecture with poor nerve regeneration. The MAb‐treated allografts maintained well‐organized nerve architecture with a dense population of well‐myelinated fibers. These animals showed functional and electrophysiological recovery. Suppression of CTL activity was nerve donor specific and the survival time of nerve donor skin grafts was prolonged, suggesting induction of alloantigen‐specific tolerance. MAb therapy directed against ICAM‐1/LFA‐1 presents a new approach for the management of the peripheral nerve allograft response.© 1995 John Wiley &Sons, Inc.
Immunopathogenesis and treatment of the guillain–barré syndrome—part II
Authors: Hartung Hans‐Peter , Toyka Klaus V. , Pollard John D. , Harvey Graham K.
Published: January 2005

In the second part of our review the role of antecedent infections in the pathogenesis of GBS is discussed. The association with Campylobacter jejuni (C. jejuni) is highlighted and the concept of molecular mimicry, i.e., sharing of epitopes between microbes and peripheral nerve, explained. Alternative mechanisms to relate an infection with the immune‐mediated neuropathy are elaborated. Current therapies of the GBS include plasma exchange, high‐dose intravenous immunoglobulins, and supportive treatment directed to secondary complications. Published therapeutic trials are reviewed and future approaches are outlined. Principles of general care are also summarized.© 1995 John Wiley &Sons, Inc.
Motor unit recruitment pattern during low‐level static and dynamic contractions
Authors: SØGaard Karen
Published: January 2005

Motor unit (MU) recruitment patterns were studied during dynamic and static contractions at workloads corresponding to 10% of maximal voluntary contraction force. The dynamic contraction consisted of a 20% flexion and extension of the elbow performed with a velocity of 10μ/s. Motor unit potential trains were recorded from the branchial biceps muscle of 6 healthy females using a quadripolar needle electrode and a computerized decomposition program. Properties of the identified MUs were derived from concentric needle EMG. A total of 119 MUs were identified during dynamic contractions, 107 MUs during static anisotonic contractions, and 96 MUs during static isotonic contractions. The main result was that MUs recruited during different contractions showed similar properties and may belong to the same part of the motoneuron pool. This indicates that MU recruitment patterns during dynamic contractions may be almost as stereotypical as during static contractions and may even activate the same MUs.© 1995 John Wiley &Sons, Inc.
Motor neuron disease: A primary disorder of corticomotoneurons?
Authors: Pamphlett Roger , Kril Jillian , Hng Tien Ming
Published: January 2005

It has been suggested that the primary site of damage in motor neuron disease (MND) is the cortical motor neuron, with secondary degeneration of spinal motor neurons. To test this hypothesis, we sought to determine if loss of corticomotoneurons in MND precedes spinal motor neuron loss. The density of corticomotoneurons was measured in 18 MND and 9 control cases using 10‐μm horizontal sections of motor cortex in the hand/arm region. The density of spinal motor neurons was measured in 10‐μm transverse sections of the lower cervical spinal cord. Corticomotoneuron and spinal motor neuron densities were decreased in MND cases compared to controls, but in MND cases there was poor correlation (r2 = 0.06) between corticomotoneuron and spinal motor neuron densities. The results indicate that corticomotoneuron and spinal motor neurons are lost at different rates in different MND patients, and that corticomotoneuron loss is unlikely to be a primary event in MND.© 1995 John Wiley &Sons, Inc.
Direct spinal stimulation for intraoperative monitoring during scoliosis surgery
Authors: Phillips Lawrence H. , Blanco John S. , Sussman Michael D.
Published: January 2005

Intraoperative electrophysiological monitoring of the spinal cord has traditionally been done by recording somatosensory evoked potentials (SEP). There is a risk that SEPs can be unaltered when significant injury to the anterior spinal cord has occurred. The purpose of this report is to describe a simple technique for intraoperative spinal cord stimulation which monitors descending pathways in the anterior spinal cord. Stimulation occurs through needle electrodes inserted into spinous processes in the rostral surgical wound, and recordings are made from electrodes in the popliteal spaces. We report our experience in monitoring spinal instrumentation in 45 patients with idiopathic scoliosis and 20 with some form of neurological disease causing scoliosis. The neurogenic motor evoked potentials (NMEP) are stable and easily recorded from the popliteal spaces in the majority of patients. We describe the case of 1 patient with Friedreich's ataxia in whom no SEPs could be recorded, but NMEPs were used successfully for monitoring. We have found that combining traditional SEP monitoring with NMEP recording provides a safe and effective method to monitor the spinal cord during surgical procedures where it is at risk.© 1995 John Wiley &Sons, Inc.
Segmental median nerve conduction measurements discriminate carpal tunnel syndrome from diabetic polyneuropathy
Authors: Hansson Sture
Published: January 2005

Median nerve conduction has been compared in CTS, with or without diabetes, and diabetic polyneuropathy. Approximately 90% of hands were correctly predicted as CTS or diabetic polyneuropathy by a comparison including the median antidromic sensory nerve conduction velocities in the elbow‐to‐wrist segment, wrist‐to‐palm segment, palm‐to‐finger segment, and the amplitude of the sensory nerve action potential. CTS with diabetes could not be distinguished from CTS without diabetes. The association between proximal and distal nerve conduction velocities was similar in CTS and diabetic polyneuropathy. A study in motor fibers showed that the hands could be classified through a combination of M‐wave latency and the more proximal motor nerve conduction velocity measurements. Independent of severity, motor and sensory nerve conduction was influenced to an equal degree in CTS and diabetic polyneuropathy. The hypothesis that both CTS and diabetic polyneuropathy can be associated with neural ischemia is discussed. © 1995 John Wiley & Sons, Inc.
Paradoxical heat sensation in uremic polyneuropathy
Authors: Yosipovitch Gil , Yarnitsky David , Mermelstein Victor , Sprecher Elliot , Reiss Jonathan , Witenberg Clara , Hemli Jeshayachu A. , Boner Geoffrey
Published: January 2005

Sensory aspects of uremic neuropathy were studied in 36 patients using clinical assessment and quantitative sensory tests (QST). The outstanding abnormality in sensory quality was perception of heat in response to low temperature stimuli. This paradoxical heat sensation was found in the foot in 42% (15) of patients, far beyond the normal prevalence of 10%. Paradoxical sensation was positively related to cold hypoesthesia (P = 0.0004) suggesting disinhibition as a possible mechanism. Paradoxical heat sensation also positively related to creatinine level (P = 0.0012). Pruritus was present in 20 patients (56%), intensity not related to any biochemical or clinical parameter. Signs of sensory polyneuropathy (PNP), based on at least two abnormal parameters in the clinical assessment or QST, were found in 39% of patients (14), of whom 11 had paradoxical heat sensation. Thus, in 4 patients (11%), this sensory aberration preceded other signs for PNP. Paradoxical heat sensation seems to be a common and often early expression of the sensory neuropathy in uremia. © 1995 John Wiley & Sons, Inc.
Recovery of sensation and somatosensory evoked potentials following toe‐to‐digit transplantation in man
Authors: Chu Nai‐Shin , Wei Fu‐Chan
Published: January 2005

Recovery of digital nerve function in 21 patients with toe‐to‐digit transplantation was evaluated by clinical sensory tests and somatosensory evoked potentials (SEPs) to median and digital nerve stimulation. The mean interval between injury and surgery was 7 months, and that between surgery and study was 31 months. The transplanted toes achieved a satisfactory but incomplete recovery in temperature (warm and cold), pinprick, touch, vibration, and two‐point discrimination in that order. The overall sensory status of the transplanted toes appeared to be closer to normal toes than to normal fingers. In SEPs from the transplanted side, median N9, N13, and N20 components had normal latency but reduced amplitude, whereas digital N9 component was usually absent, but N13 and N20 components had prolonged latency and reduced amplitude. Transplantation performed within 1 month after injury prevented amplitude reduction in median SEPs and latency prolongation in digital SEPs. The SEP data suggest that timing of surgery was critical in preventing retrograde effect on the median nerve, and that recovery of digital nerve function was incomplete correlating with clinical sensory findings. © 1995 John Wiley & Sons, Inc.
Restoration of conduction in the spinal roots correlates with clinical recovery from experimental autoimmune encephalomyelitis
Authors: Chalk Jonathan B. , McCombe Pamela A. , Pender Michael P.
Published: January 2005

In the Lewis rat, acute experimental autoimmune encephalomyelitis (EAE) induced by inoculation with myelin basic protein (MBP) and adjuvants is characterized by tail and hindlimb weakness that resolves spontaneously after several days. In rats with neurological signs of this form of EAE (MBP‐EAE) we have previously demonstrated demyelination and nerve conduction block in the proximal peripheral nervous system (PNS) and in the central nervous system (CNS). The present study was performed to assess conduction in the PNS and CNS, after recovery from acute MBP‐EAE, using direct recordings from surgically exposed spinal roots and spinal cord dorsal columns. The study revealed that 1–2 weeks after clinical recovery from tail paralysis there was almost complete restoration of conduction in the sacral spinal roots but persistent severe conduction abnormalities in the dorsal columns. Significant restoration of conduction through the dorsal columns occurred over the following 2 weeks. These findings indicate that PNS conduction block due to a demyelinating polyradiculitis is a major cause of the neurological signs of acute MBP‐EAE in the Lewis rat.© 1995 John Wiley & Sons, Inc.
Characteristics of motor unit discharge in subjects with hemiparesis
Authors: Gemperline Judith J. , Allen Sarah , Walk David , Rymer William Z.
Published: January 2005

We studied the discharge rates recruitment characteristics of single motor units in paratic and contralateral arm muscles of 6 hemiparetic subjects. Motor unit activity in bicapes brachii was recorded at different elbow torques, and the activity related both to the mean level of surface electromyographic activity, and to the degree of weakness. In 3 of the 6 subjects, there were significant reductions in mean discharge rate of motor units in the paretic muscle. All 6 subjects showed compression of the range of motoneuron recuitment forces, and a failure to increase motor unit discharge rate during voluntary force increases in paretic muscles. These rate reductions could potentially alter the precise match of motoneuron properties to the mechanical properties of the innerved muscle fibers, and reduce the efficiency of muscle contraction. This reduction could lead, in turn to increased effort, to fatigue, and ultimately to a sense of weaknes for voluntary force generation.© 1995 John Wiley & Sons, Inc.
Dystrophin‐positive fibers in duchenne dystrophy: Origin and correlation to clinical course
Authors: Fanin Marina , Danieli Gian Antonio , Cadaldini Morena , Miorin Marta , Vitiello Libero , Angelini Corrado
Published: January 2005

In 132 DMD muscle biopsies we investigated the presence of dystrophin‐positive fibers and the relationship of dystrophin immunohistochemical pattern to the clinical severity of the disease. Reverted fibers were detected in 37% of patients; their prevalence increased significantly in each biopsy with age of patients. We suggest that reversion occurs in satellite cells, when muscle differentiation is completed. The longitudinal extent of dystrophin‐positive domain spans a maximum length of 900 μm. No correlation was found between the presence of reverted fibers and the clinical severity of DMD, whereas a milder form of Duchenne dystrophy was observed in patients showing a faint reaction in all fibers. The occurrence of reverted fibers is independent of the type of gene mutation; however, a higher proportion of cases with reverted fibers was found among patients with gene duplications.© 1995 John Wiley & Sons, Inc.
Facilitation of magnetic motor evoked potentials during the mixed nerve silent period
Authors: Young Michael S. , Triggs William J. , Gerstle Gabriella
Published: January 2005

We studied motor nueron excitability during the mixed nerve silent period (MNSP) in a hand muscle using magnetic motor evoked potentials (MEPs) and F‐waves. MEPs elicited between the V1 and V2 potentials of the MNSP were much larger than control MEPs elicited at rest, and were even comparable in size to control MEPs occured without shortening of MEP latency, suggesting a supraspinal mechanism. MEPs were facilitated during the MNSP when elicited with a figure‐8‐shaped coil in a posterior–anterior orientation, but not when MEPs of the same size were elicited with the coil held in a lateral–medial orientation. F‐waves elicited during the MNSP were variable between subjects, and not consistently different from control F‐waves elicited at rest. Our findings may reflect increased cortical motor excitability during the MNSP, possibly related to activation of muscle afferents by mixed nerve stimulation. © John Wiley & Sons, Inc.
Manganese toxicity upon overexposure
Authors: Crossgrove Janelle , Zheng Wei
Published: January 2005

Manganese (Mn) is a required element and a metabolic byproduct of the contrast agent mangafodipir trisodium (MnDPDP). The Mn released from MnDPDP is initially sequestered by the liver for first‐pass elimination, which allows an enhanced contrast for diagnostic imaging. The administration of intravenous Mn impacts its homeostatic balance in the human body and can lead to toxicity. Human Mn deficiency has been reported in patients on parenteral nutrition and in micronutrient studies. Mn toxicity has been reported through occupational (e.g. welder) and dietary overexposure and is evidenced primarily in the central nervous system, although lung, cardiac, liver, reproductive and fetal toxicity have been noted. Mn neurotoxicity results from an accumulation of the metal in brain tissue and results in a progressive disorder of the extrapyramidal system which is similar to Parkinson's disease. In order for Mn to distribute from blood into brain tissue, it must cross either the blood–brain barrier (BBB) or the blood–cerebrospinal fluid barrier (BCB). Brain import, with no evidence of export, would lead to brain Mn accumulation and neurotoxicity. The mechanism for the neurodegenerative damage specific to select brain regions is not clearly understood. Disturbances in iron homeostasis and the valence state of Mn have been implicated as key factors in contributing to Mn toxicity. Chelation therapy with EDTA and supplementation with levodopa are the current treatment options, which are mildly and transiently efficacious. In conclusion, repeated administration of Mn, or compounds that readily release Mn, may increase the risk of Mn‐induced toxicity. Copyright © 2004 John Wiley & Sons, Ltd.
Functional mapping of neural pathways in rodent brain in vivo using manganese‐enhanced three‐dimensional magnetic resonance imaging
Authors: Watanabe Takashi , Frahm Jens , Michaelis Thomas
Published: January 2005

This work presents three‐dimensional MRI studies of rodent brain in vivo after focal and systemic administration of MnCl2. Particular emphasis is paid to the morphology and dynamics of Mn2+‐induced MRI signal enhancements, and the physiological mechanisms underlying cerebral Mn2+ uptake and distribution. It turns out that intravitreal and intrahippocampal injections of MnCl2 emerge as useful tools for a delineation of major axonal connections in the intact central nervous system. Subcutaneous administrations may be exploited to highlight regions involved in fundamental brain functions such as the olfactory bulb, inferior colliculus, cerebellum and hippocampal formation. Specific insights into the processes supporting cerebral Mn2+ accumulation may be obtained by intraventricular MnCl2 injection as well as by pharmacologic modulation of, for example, hippocampal function. Taken together, Mn2+‐enhanced MRI opens new ways for mapping functioning pathways in animal brain in vivo with applications ranging from assessments of transgenic animals to follow‐up studies of animal models of human brain disorders. Copyright © 2004 John Wiley & Sons, Ltd.
Anesthetic blocking of nerve membrane conductances by internal and external applications
Authors: Narahashi Toshio , Moore John W. , Poston Robin N.
Published: January 2005

Dibucaine hydrochloride, pentobarbital sodium, tropine p‐tolyl acetate hydrochloride (tertiary form), and tropine p‐tolyl acetate methiodide (quaternary form) reversibly blocked both peak transient and steadystate components of conductance changes from either side of the squid nerve membrane. With external and internal applications of dibucaine and with internal application of the tertiary topine, the steady‐state current declined somewhat, leaving a “hump.” The time to the early peak transient current was unaffected by either external or internal application of dibucaine, but prolonged by either external or internal application of pentobarbital. The curve relating the peak transient conductance to the membrane potential was shifted along the potential axis in the direction of depolarization by external or internal application of pentobarbital. It is suggested that the mechanism of blockage of the peak transient conductance by these anesthetic agents is different from that by tetrodotoxin or by uncharged lipid‐soluble chemicals.
Circadian rhythm of responsiveness in crayfish visual units
Authors: Aréchiga Hugo , Wiersma C. A. G.
Published: January 2005

Metal microelectrodes were implanted in the optic nerve of the crayfish, Procambarus clarki, and the activity of the sustaining fibers (units which react tonically to changes in illumination) was continuously recorded over periods up to 8 weeks. In animals kept in darkness, the response to periodic test light pulses was found to vary in a circadian manner. The duration of the cycles varied between 22 24 hr, with a phase of high responsiveness during the subjective night, which abruptly changed to one of low responsiveness at subjective dawn. The phase, amplitude, and shape of the cycles were modifiable by light pulses. The spontaneous activity of these units in darkness showed a similar fluctuation, and so did the electroretinogram amplitude, the spontaneous motor activity of the animal, as indicated by records from mechanoreceptive and activity fibers (units which are activated, directly or indirectly by body movements), and the motor responsiveness to light. The time course of these cycles suggests that they are driven by a common “clock,” through humoral mechanisms.
The effect of prolonged cortical spreading depression on learning and memory in rats
Authors: Burešová Olga , Bureš Jan
Published: January 2005

Memory impairment evoked by prolonged cortical spreading depression (PCSD) was examined in 387 rats. PCSD was maintained for 5 hrs by repeated applications of 25% KCl to the exposed cortical surface. Behavioral tests were performed 24 or more hours after PCSD. Whereas a single application of 25% KCl does not affect subsequent learning, acquisition of a simple T‐maze avoidance reaction is slower and exploration of a novel environment is impaired during 3–5 days following PCSD. The effect of CSD on the memory depends on the total duration of the depression. While a single KCl application has a negligible amnesic effect, PCSD prevents later retrieval of moderately overlearned (to‐criterion learning on 3 consecutive days) T‐maze habit but does not affect markedly overlearned behavior (to‐criterion learning on 12 consecutive days). Similarly PCSD impairs the exploration of a novel but not of a familiar environment. Even moderately overlearned habits remain unaffected by PCSD applied 7–12 days after completion of learning. The amnesic effects of PCSD are not permanent, retrieval of the impaired experience improves over 7–14 days to control level. Since spontaneous EEG and evoked responses are more or less normal 24 hr after PCSD, it is proposed that PCSD interferes with the metabolic phase of engram formation. The relative significance of the components of the PCSD effect affecting learning and memory is discussed.
Glutamate release from the retina during spreading depression
Authors: Van Harreveld A. , Fifková Eva
Published: January 2005

The retina was charged with 14C labled glutamate in a near isotonic KCl solution containing, in addition to the label, 25 mM unlabeled glutamate. In extracts of retinas thus charged most of the label was present as glutamate, an appreciable amount as glutamine, and some as aspartate, γ‐aminobutyric acid and other, probably non‐aminated, metabolites of glutamate.

The charged retinas, superfused in a chamber, were stimulated either chemically with unlabeled glutamate or KCl solutions, or electrically with direct current. These stimuli caused a transient increase in the transparency of the retina, indicative of spreading depression. Only minute portions of the superfusion solution were collected, and subjected to paper electrophoresis. The radioactivity of the labeled spots was determined with a strip counter. When not stimulated the retina released mostly glutamine, but during and after the various modes of stimulation the release of glutamate increased markedly. Repeated stimulation with short current pulses did not cause a transparency increase and did not enhance the glutamate release. During spontaneous spreading depressions a slight increase in glutamate release was observed. The possibility that glutamate release is the primary mechanism in spreading depression is discussed.
Retinular and eccentric cell morphology in the neural plexus of Limulus lateral eye
Authors: Schwartz E. A.
Published: January 2005

Retinular and eccentric cells of Limulus lateral eye are stained by intracellular iontophoretic injection of Procion M4R. Eccentric cell branching can be divided into multiple neuropile, long lateral branches and distal collaterals. Retinular cells possess only short axon spines. This morphology is discussed in relation to the known physiology of cell interactions.
Characterization of the fast and slow components of axonal transport in retinal ganglion cells
Authors: Karlsson J. O. , Sjöstrand J.
Published: January 2005

The constituent proteins of the fast (110–150 mm/day) and slow (1.5–2 mm/day) components of axonal transport in the retinal ganglion cells of the rabbit were investigated. The fast and slow components were labelled by intraocular injection of (3H)‐ and (14C)‐leucine, respectively.

Subcellular fractionation of the optic nerve and tract and subsequent gel electrophoresis of the fractions showed that most of the soluble proteins moved with the slow phase of axonal transport, whereas only some of the soluble proteins were transported with the rapid phase.

Extraction of the microsomal fraction with triton X‐100 resulted in the solubilization of highly labelled proteins belonging to the rapid phase. These proteins showed a relatively low electrophoretic mobility.
Effect of the convulsant methionine sulfoximine on the in vivo uptake and metabolism of d‐methionine in rat brain
Authors: Ghittoni Nora E. , Sellinger Otto Z.
Published: January 2005

D‐methionine was administered intraperitoneally to rats in tracer (2–2.5 μmoles/kg) and large doses (4.7 mmoles/kg) and the brain levels of total (D + L) methionine, as well as of cysteine (+cystine) and glutathione were determined. The effect of co‐administering the convulsant agent, L‐methionine‐DL‐sulfoximine (MSO) was also examined. The administration of tracer doses of C12‐D‐methionine resulted in a doubling of total brain methionine within 4 hours post‐injection, but only in a moderate increase of the levels of cysteine. When C14‐D‐methionine was used as tracer, the peak increase of the isotopic methionine pool and a peak accumulation of 0.35% of the injected radioactivity were noted in the brain within 1.5 hours. When 4.7 mmoles/kg of D‐methionine were administered, total brain methionine and cysteine increased by 4‐ and 3‐fold respectively, the former peaking at 1.5 hr and the latter at 2.5 hr post‐injection. The administration of MSO retarded the attainment of these peaks. It could also be shown that while about 65% of the total brain methionine existed as the D‐isomer 1.5 hr after its administration, only 46% was still present as the D‐isomer 0.5 hr later. When MSO was administered simultaneously with D‐methionine, the corresponding percentage values stood at 70% at 1.5 and at 2 hr. The results, therefore, suggest that even though D‐methionine reaches the brain largely unchanged, its uptake and its conversion to the natural L‐isomer may be inhibited by MSO under certain conditions and hence its conversion to cysteine retarded.
Serotonin metabolism in the brains of mice sensitive or resistant to audiogenic seizures
Authors: Kellogg Carol
Published: January 2005

Properties involved in the maintenance of the steady‐state level of serotonin were studied in the brains of mice showing a genetically determined susceptibility or resistance to audiogenic seizures. Animals susceptible to sezures appear to possess an inefficient 5‐HT system which stimulates a compensatory increase in neuronal activity resulting in decreased 5‐HT levels and increased 5‐HT turnover. Biochemical mechanisms that could be responsible for such an inefficiency are discussed.
The movement of sulfate and thiosulfate into in vivo choroid plexus
Authors: Pollay Michael , Kaplan Ralph J.
Published: January 2005

The accumulation of sulfate (SO4) and thiosulfate (S2O3) in the choroid plexus, brain, and cerebrospinal fluid (CSF) of the rat was measured at various plasma levels of these anions. Increasing the plasma SO4  or S2O3  concentration levels 40‐ and 580‐fold, respectively, resulted in a linear increase in CSF, brain and choroid plexus concentration of these ions. The relationship between the concentration of these ions in CSF and choroid plexus was also approximately linear over a wide CSF concentration range. In addition, S2O3 did not appear to influence the relation between the concentration of SO4 in choroid plexus and CSF. The results seem to indicate that there is no saturation of the mechanism responsible for maintaining the low SO4 or S2O3 concentration in CSF nor does there appear to be competition between these anions for clearance from the CSF. These findings are in conflict with data supporting the active transport of SO4 and S2O3 from the CSF across the CSF‐blood barrier (choroid plexus).
The flow of mitochondria in chicken sciatic nerve
Authors: Jeffrey P. L. , James K. A. C. , Kidman A. D. , Richards A. M. , Austin L.
Published: January 2005

Mitochondrial flow in chicken sciatic nerve has been followed using [59Fe] as a marker for mitochondrial cytochromes.

Radioactively labelled iron was injected into the ventral horn of the chicken spinal cord in the region of the cell bodies of the motor neurons, whose axons pass into the sciatic nerve. Protein‐bound [59Fe] was found to move at a slow rate (1–4 mm/day) in the sciatic nerve. The total protein bound [59Fe] in the nerve reached a maximum at 9 days and then gradually diminished.

The percentage of label in the mitochondria (expressed both as total and protein bound radioactivity) as compared to the total homogenate of the spinal cord increased up to 14 days and then showed a gradual levelling off.

Subcellular fractionation of both spinal cord and sciatic nerve revealed that the mitochondrial fraction obtained by discontinuous gradient centrifugation had the highest specific activity of the fractions isolated. The major portion of this label is present in cytochromes a and b, localized in the mitochondria.

Colchicine which has been shown to inhibit both rapid and slow axonal protein flow, markedly reduced the amount of protein bound [59Fe] in the sciatic nerve.
Synaptic stimulation of RNA metabolism in the giant neuron of Aplysia californica
Authors: Berry R. W. , Cohen M. J.
Published: January 2005

We have monitored the incorporation of tritiated uridine into RNA by the giant neuron of the Aplysia abdominal ganglion. Synaptic stimulation evoking a mean of 3,000 impulses in the neuron increased incorporation by about 67%. Incorporation was proportional to the number of stimuli given and to the number of synaptically evoked action potentials produced in the stimulated neuron. Stimulation did not alter uridine uptake or the percentage of intracellular label appearing in UTP. The effect of stimulation cannot be accounted for by glial incorporation.
Regeneration of ventral root axons into dorsal roots as shown by increased acetylcholinesterase activity
Authors: Ranish N. , Ochs S. , Barnes C. D.
Published: January 2005

Regeneration of ventral root axons of the lumbar seventh (L7) segment into the dorsal L7 roots on the opposite side of cat spinal cord was shown by changes in the levels of acetylcholinesterase (AChE) and pseudocholinesterase (PsChE). Low levels of AChE and PsChE were found in control dorsal roots, but when regenerating ventral root fibers entered the dorsal roots, there was a doubling of AChE activity within 2 weeks. Growth appears to start some time after the first week; this is in accord with earlier evidence based on axoplasmic flow of isotope labeled protein in this experimental preparation.

The level of AChE activity in the reinnervated dorsal roots increased continually for about 100 days before reaching a plateau at approximately 20 × control levels. The gradual increase and the plateau of AChE activity is in accord with a maturation of the ventral root fibers which had regenerated into the dorsal roots. PsChE in the dorsal roots changes in parallel with AChE in a ratio of 1:10, suggesting that PsChE may in part be localized in the regenerating axons.
The effect of synaptic stimulation on RNA and protein metabolism in the R2 soma of Aplysia
Authors: Wilson David L. , Berry Robert W.
Published: January 2005

Excitatory synaptic stimulation of the R2 neuron in the abdominal ganglion of Aplysia californica causes an increased incorporation of 3Huridine into RNA. However, this could be the result of a change in precursor specific activity rather than an increase in RNA synthesis. We find that at low external uridine concentrations (1.5 μM) there is no increase in 3H‐uridine incorporation correlated with synaptic stimulation. In addition, no change in incorporation of 3H‐leucine into total protein or in the pattern of newly‐synthesized proteins, resolved by electrophoresis on SDS‐polyacrylamide gels, was detected with stimulation. Since the R2 neuron can be stimulated without a detectable change in RNA or protein synthesis, we conclude that the increase in incorporation observed at high external uridine concentrations (100 μM) could be caused by increased specific activity in a precursor pool rather than by an RNA synthesis change.
Slow accumulation of choline acetyltransferase in crushed sciatic nerves of the rat
Authors: Saunders N. R. , Dziegielewska K. , Häggendal C. J. , Dahlström A. B.
Published: January 2005

Choline Acetyltransferase (CHAc) activity has been estimated using a microradiochemical method in short segments of rat sciatic nerve at different times after crushing the nerve once or with a second crush 2 cm distal to the first. Above a single or proximal crush, the CHAc levels rose slowly in the 5 mm immediately above the crush to reach about 1 1/2 times control at 24 hr. Distal to a single crush and between two crushes no change was detected in CH‐Ac‐activity up to 18–24 hr. The results are discussed in relation to the rapid accumulation of acetylcholine (ACH) above a crush, and redistribution between two crushes which have previously been demonstrated in the same preparation. It is concluded that the rate of transport of CHAc is probably much slower than that of ACH, and that their mechanismes of transport are not the same.
The neuronal basis of behavior in Tritonia. IV. The central origin of a fixed action pattern demonstrated in the isolated brain
Authors: Dorsett D. A. , Willows A. O. D. , Hoyle G.
Published: January 2005

The mechanisms which initiate and integrate the patterned sequence of activity in the interacting cell groups responsible for the swimming behavior of Tritonia remain operative after complete isolation of the brain from the periphery. Following isolation, a short electrical stimulus applied to a nerve from the oral veil leads to patterned bursting in the flexion neurons of the pedal ganglia, which is identical to that occurring in the same cells during the swimming escape response.

Direct evidence of cell‐cell interaction in the form of unitary postsynaptic potentials was not obtained, but the close synchronization of burst patterning in both ipsilateral and contralateral synergists infers the existence of positive feed back between many neurons of the group. Alternating bursts of impulses in functional antagonists are associated with reciprocal inhibition between the two networks. As all possibility of proprioceptive feedback has been excluded in the isolated brain, it is evident that the motor output pattern for the escape‐swimming response has been generated by a central mechanism without reference to sensory input, which serves only to trigger the action.
Genetic manipulation of motor output in shaker mutants of Drosophila
Authors: Trout W. E. , Kaplan W. D.
Published: January 2005

Hk1, Hk2, Sh5, and Eag are sex‐linked behavior mutants of Drosophila which shake their legs vigorously when etherized. The shaking rate increases with age to a plateau by five days after eclosion; it is decreased by increasing ether concentrations. Eag is temperature sensitive, shaking vigorously at 30°C but not at all below 20°C. Hk1 and Hk2 have cyclic shaking patterns consisting of three to six periods of shaking per minute. Hk1 stakes more, and has longer shaking periods than Hk2; the heterozygote Hk1/Hk2 is intermediate. When heterozygous with a deletion for the locus, both Hk1 and Hk2 shake more, the pattern of Hk2 resembling that of Hk1. Therefore, these alleles may differ only quantitatively. The shaking pattern of Sh5 is distinctly different, consisting of short bursts of shaking two or three times a second. Flies with both Hk and Sh5 mutations in different combinations can have a pattern which is Hk‐type, Sh5‐type, or both simultaneously, depending upon the geno‐type. The shaking of Hk1 is known to be a consequence of abnormally firing neurons in the thoracic ganglion. Therefore, the interactions between Hk and Sh5 are probably between two different mutant effects upon the motor system, both subject to genetic manipulation.
Levels of glutamate decarboxylase, choline acetyltransferase and acetylcholinesterase in identified motorneurons of the locust
Authors: Emson P. C. , Burrows M. , Fonnum F.
Published: January 2005

Isolated somata of identified motorneurons in the metathoracic ganglion of the locust were analyzed for glutamate decarboxylase (GAD), choline acetyltransferase (ChAc), acetylcholinesterase (AChE), and aromatic amino acid decarboxylase (AAD). Isolated inhibitory motorneuron somata have GAD activity but those of excitatory motorneurons do not. Since this enzyme is responsible for the synthesis of gamma amino butyric acid there is a metabolic basis for these motorneurons to accumulate GABA. In contrast to the specific localization of GAD in inhibitory motorneurons, AChE was found in large amounts in all motorneurons tested. The specific activity of ChAc and AAD in both inhibitory and excitatory motorneurons were similar or lower than the specific activity of the whole ganglion. Degeneration experiments suggest that ChAc is mainly localized in the sensory neurons.
Effects of fluorodeoxyuridine on growth and choline acetyltransferase activity in fetal rat brain cells in surface culture
Authors: Schrier Bruce K. , Shapiro Donald L.
Published: January 2005

Inhibition of DNA synthesis by 5‐fluoro‐2‐deoxyuridine in cultures of rapidly growing fetal rat brain cells resulted in a marked decrease in the development of total activity and a stimulation of specific activity (pmoles\min\μg DNA) of the enzyme choline acetyltransferase, a putative neuronal marker. Similar treatment of higher density, less rapidly dividing cultures of the same age resulted in no change in total activity development, although an increment in specific activity was again found. The findings appeared to be the result of inhibition of DNA synthesis by fluorodeoxyuridine, rather than secondary effects of the drug, and indicate either that the nucleotide analog specifically inhibited choline acetyltransferase gene expression in rapidly growing, but not in stationary cultures, or that cells capable of producing the enzyme activity were able to proliferate in culture. If the latter were true and if cells producing the enzyme were, in fact, neurons, it may be possible to clone untransformed neurons for in‐depth study in a culture system.
Biochemical and cytochemical studies of the development of choline acetyltransferase and acetylcholinesterase in organotypic cultures of chick neural tube
Authors: Kim Seung U. , Oh Tae H. , Wenger Eleanor L.
Published: January 2005

Choline acetyltransferase (ChAc) and acetylcholinesterase (AChE) activities have been studied in organotypic cultures of early chick neural tube. During the first week in culture the ChAc activity remains extremely low at which time it can not be demonstrated histochemically in early neurons. It increases rapidly during the second and third weeks in culture, as demonstrated biochemically and histochemically. AChE activity rises rapidly during the first week, and then more gradually for the remainder of the culture period; it can be demonstrated histochemically in early neurons and well differentiated multipolar neurons throughout this period. In our culture system biochemical differentiation (ChAc and AChE activity) occurs concomitantly with morphological differentiation.