bluuebunny/crossref_metadata_2025_split huggingface dataset:
Establishment and characterization of spontaneously immortalized Schwann cells from murine model of globoid cell leukodystrophy (twitcher)
Authors: Shen Jin‐Song , Watabe Kazuhiko , Meng Xing‐Li , Ida Hiroyuki , Ohashi Toya , Eto Yoshikatsu 
Published: August 2002

AbstractThe twitcher mouse is a murine model of human globoid cell leukodystrophy (GLD; Krabbe disease) caused by a genetic defect in the activity of galactosylceramidase (GALC). An accumulation of cytotoxic metabolite, galactosylsphingosine (psychosine), in myelin forming cells (oligodendrocytes and Schwann cells) of the twitcher mouse as well as patients with GLD has been suggested to cause dysfunction of these cells and subsequent demyelination in the central and peripheral nervous system. To investigate further the cellular pathomechanism of GLD, we established spontaneously immortalized Schwann cell lines from the twitcher mouse. Long‐term cultures of Schwann cells derived from dorsal root ganglia and consecutive peripheral nerves of 3‐week‐old twitcher mice were maintained for 6 months, and spontaneously developed colonies were expanded further and characterized. One of the cell lines, designated TwS1, showed distinct Schwann cell phenotypes, was passaged twice a week and maintained for over 10 months without phenotypic alterations. The TwS1 cells had a nonsense mutation in the GALC genome, and showed markedly reduced GALC activity and elevated psychosine levels. Ultrastructurally, varieties of cytoplasmic inclusions were demonstrated in TwS1 cells. When TwS1 cells were infected with a retrovirus vector encoding GALC, GALC activity was markedly increased and psychosine levels were significantly decreased. These immortalized Schwann cells can be useful in studies on the nervous system lesions in GLD. © 2002 Wiley‐Liss, Inc.
Acute administration of Ginkgo biloba extract (EGb 761) affords neuroprotection against permanent and transient focal cerebral ischemia in Sprague‐Dawley rats
Authors: Lee E‐Jian , Chen Hung‐Yi , Wu Tian‐Shung , Chen Tsung‐Ying , Ayoub Issam A. , Maynard Kenneth I. 
Published: August 2002

AbstractWe examined the neuroprotective action of a standardized extract of Ginkgo biloba leaves (EGb 761) in permanent and transient middle cerebral artery (MCA) occlusion models in Sprague‐Dawley rats. Forty‐four animals were given either EGb 761 (50–200 mg/kg) or vehicle intraperitoneally, 1 hr before permanent MCA occlusion, to evaluate the dose‐response effects. An additional 58 animals received EGb 761 (200 mg/kg) or vehicle, 0.5– 4 hr after permanent MCA occlusion, for establishing the therapeutic window. Delayed treatment was also employed in 110 animals treated with either EGb 761 (100–200 mg/kg) or vehicle at 2–3 hr following transient focal cerebral ischemia induced by MCA occlusion for 2 hr. Neurobehavioral scores were determined 22–24 hr after permanent MCA occlusion and either 3 or 7 days after transient MCA occlusion, and brain infarction volumes were measured upon sacrifice. Local cortical blood flow (LCBF) was serially measured in a subset of animals receiving EGb 761 (100–200 mg/kg) or vehicle, 0.5 hr and 2 hr after permanent and transient MCA occlusion, respectively. Relative to vehicle‐treated controls, rats pretreated with EGb761 (100 and 200 mg/kg) had significantly reduced infarct volumes, by 36% and 49%, respectively, and improved sensory behavior (P < 0.05). Delayed treatment with EGb 761 also significantly reduced brain infarction, by 20–29% and 31%, when given up to 2 and 3 hr following transient and permanent MCA occlusion, respectively, whereas improved neurobehavioral scores were noted up to 2 hr after the onset of MCA occlusion (P < 0.05). LCBF was significantly improved in the ipsilateral cortex following the EGb 761 treatment, whereas a higher dose showed a more sustained effect. In conclusion, EGb 761 protected against transient and permanent focal cerebral ischemia and was effective after a prolonged reperfusion period even when therapy is delayed up to 2 hr. This neuroprotection may be at least partially attributed to the beneficial effects of selectively improved LCBF in the area at risk of infarction. © 2002 Wiley‐Liss, Inc.
Tobacco cembranoids block behavioral sensitization to nicotine and inhibit neuronal acetylcholine receptor function
Authors: Ferchmin P.A. , Lukas R.J. , Hann R.M. , Fryer J.D. , Eaton J.B. , Pagán O.R. , Rodríguez A.D. , Nicolau Y. , Rosado M. , Cortés S. , Eterović V.A. 
Published: August 2002

AbstractCembranoids are cyclic diterpenoids found in tobacco and in marine invertebrates. The present study established that tobacco cembranoids inhibit behavioral sensitization to nicotine in rats and block several types of nicotine acetylcholine receptors (AChRs). 1) At the behavioral level, rat locomotor activity induced by nicotine was significantly increased after seven daily nicotine injections. This sensitization to nicotine was blocked by mecamylamine (1 mg/kg) and by the cembranoids eunicin, eupalmerin acetate (EUAC), and (4R)‐2,7,11‐cembratriene‐4‐6‐diol (4R), each at 6 mg/kg. None of these compounds modified locomotor activity of nonsensitized rats. 2) In cells expressing human AChRs, cembranoids blocked carbamoylcholine‐induced 86Rb+ flux with IC50 in the low micromolar range. The cell lines used were the SH‐EP1‐hα4β2 cell line heterologously expressing human α4β2‐AChR, the SH‐SY5Y neuroblastoma line naturally expressing human ganglionic α3β4‐AChR, and the TE671/RD cell line naturally expressing embryonic muscle α1β1γδ‐AChR. The tobacco cembranoids tested were 4R and its diastereoisomer 4S, and marine cembranoids tested were EUAC and 12,13‐bisepieupalmerin. 3) At the molecular level, tobacco (4R and 4S) and marine (EUAC) cembranoids blocked binding of the noncompetitive inhibitor [3H]tenocyclidine to AChR from Torpedo californica electric organ. IC50 values were in the submicromolar to low‐micromolar range, with 4R displaying an order of magnitude higher potency than its diastereoisomer, 4S. J. Neurosci. Res. 64:18–25, 2001. © 2001 Wiley‐Liss, Inc.
Chemokine antagonist infusion promotes axonal sparing after spinal cord contusion injury in rat
Authors: Ghirnikar R.S. , Lee Y.L. , Eng L.F. 
Published: August 2002

AbstractSpinal cord injury produced by mechanical contusion causes the onset of acute and chronic degradative events. These include blood brain barrier disruption, edema, demyelination, axonal damage and neuronal cell death. Posttraumatic inflammation after spinal cord injury has been implicated in the secondary injury that ultimately leads to neurologic dysfunction. Studies after spinal cord contusion have shown expression of several chemokines early after injury and suggested a role for them in the ordered recruitment of inflammatory cells at the lesion site (McTigue et al. [1998] J. Neurosci. Res. 53:368–376; Lee et al., [2000] Neurochem Int). We have demonstrated previously that infusion of the broad‐spectrum chemokine receptor antagonist (vMIPII) in the contused spinal cord initially attenuates leukocyte infiltration, suppresses' gliotic reaction and reduces neuronal damage after injury. These changes are accompanied by increased expression of bcl‐2, the endogenous apoptosis inhibitor, and reduced neuronal apoptosis (Ghirnikar et al. [2000] J. Neurosci. Res. 59:63–73). We demonstrate that 2 and 4 weeks of vMIPII infusion in the contusion‐injured spinal cord also results in decreased hematogenous infiltration and is accompanied by reduced axonal degeneration in the gray matter. Luxol fast blue and MBP immunoreactivity indicated reduced myelin breakdown in the dorsal and ventral funiculi. Increased neuronal survival in the ventral horns of vMIPIl infused cords was seen along with increased bcl‐2 staining in them. Immunohistochemical identification of fiber phenotypes showed increased presence of calcitonin gene related peptide, choline acetyl transferase and tyrosine hydroxylase positive fibers as well as increased GAP43 staining in treated cords. These results suggest that sustained reduction in posttraumatic cellular infiltration is beneficial for tissue survival. A preliminary report of this study has been published (Eng et al. [2000] J. Neurochem. 74(Suppl):S67B). In contrast to vMIPII, infusion of MCP‐1 (9‐76), a N‐terminal analog of the MCP‐1 chemokine showed only a modest reduction in cellular infiltration at 14 and 21 dpi without significant tissue survival after spinal cord contusion injury. Comparing data on tissue survival obtained with vMIPII and MCP‐1 (9‐76) further validate the importance of the use of broad‐spectrum antagonists in the treatment of spinal cord injury. Controlling the inflammatory reaction and providing a growth permissive environment would enhance regeneration and ultimately lead to neurological recovery after spinal cord injury. J. Neurosci. Res. 64:582–589, 2001. Published 2001 Wiley‐Liss, Inc.
Role of kainate receptor activation and desensitization on the [Ca2+]i changes in cultured rat hippocampal neurons
Authors: Silva Ana P. , Malva João O. , Ambrósio António F. , Salgado António J. , Carvalho Arsélio P. , Carvalho Caetana M. 
Published: August 2002

AbstractWe investigated the role of kainate (KA) receptor activation and desensitization in inducing the increase in the intracellular free Ca2+ concentration ([Ca2+]i) in individual cultured rat hippocampal neurons. The rat hippocampal neurons in the cultures were shown to express kainate receptor subunits, KA2 and GluR6/7, either by immunocytochemistry or by immunoblot analysis. The effect of LY303070, an α‐amino‐3‐hydroxy‐5‐methyl‐isoxazole‐4‐propionate (AMPA) receptor antagonist, on the alterations in the [Ca2+]i caused by kainate showed cell‐to‐cell variability. The [Ca2+]i increase caused by kainate was mostly mediated by the activation of AMPA receptors because LY303070 inhibited the response to kainate in a high percentage of neurons. The response to kainate was potentiated by concanavalin A (Con A), which inhibits kainate receptor desensitization, in 82.1% of the neurons, and this potentiation was not reversed by LY303070 in about 38% of the neurons. Also, upon stimulation of the cells with 4‐methylglutamate (MGA), a selective kainate receptor agonist, in the presence of Con A, it was possible to observe [Ca2+]i changes induced by kainate receptor activation, because LY303070 did not inhibit the response in all neurons analyzed. In toxicity studies, cultured rat hippocampal neurons were exposed to the drugs for 30 min, and the cell viability was evaluated at 24 hr using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The selective activation of kainate receptors with MGA, in the presence of Con A, induced a toxic effect, which was not prevented by LY303070, revealing a contribution of a small subpopulation of neurons expressing kainate receptors that independently mediate cytotoxicity. Taken together, these results indicate that cultured hippocampal neurons express not only AMPA receptors, but also kainate receptors, which can modulate the [Ca2+]i and toxicity. J. Neurosci. Res. 65:378–386, 2001. © 2001 Wiley‐Liss, Inc.
Schwann cells and oligodendrocytes read distinct signals in establishing myelin sheath thickness
Authors: Elder Gregory A. , Friedrich Victor L. , Lazzarini Robert A. 
Published: August 2002

AbstractSchwann cells and oligodendrocytes produce myelin sheaths of widely varying sizes. How these cells determine the size of myelin sheath for a particular axon is incompletely understood. Axonal diameter has long been suspected to be a signal in this process. We have analyzed myelin sheath thickness in L5 lumbar root and spinal cord white matter of a series of mouse mutants with diminished axonal calibers resulting from a deficiency of neurofilaments (NFs). In the PNS, average axonal diameters were reduced by 20–37% in the NF mutants. Remarkably, the average myelin sheath thickness remained unchanged from control values, and regression analysis showed sheaths abnormally thick for a given size of axon. These data show that a genetically induced reduction in axonal caliber does not cause a reduction in myelin sheath thickness in PNS and indicate that Schwann cells read some intrinsic signal on axons that can be uncoupled from axonal diameter. Interestingly, myelin sheaths in the spinal cord of these animals were not abnormally thick, arguing that axonal diameter may contribute directly to the regulation of myelination in the CNS and that oligodendrocytes and Schwann cells use different cues to set myelin sheath thickness. J. Neurosci. Res. 65:493–499, 2001. © 2001 Wiley‐Liss, Inc.
Work status and organizational citizenship behavior: a field study of restaurant employees
Authors: Stamper Christina L. , Dyne Linn Van 
Published: August 2002

AbstractThis survey‐based field study of 257 service employees developed and tested a model of differences in the organizational citizenship behavior of full‐time and part‐time employees based on social exchange theory. Questionnaire data from matched pairs of employees and their supervisors demonstrated that part‐time employees exhibited less helping organizational citizenship behavior than full‐time employees, but there was no difference in their voice behavior. We also predicted that both preferred work status (an individual factor) and organizational culture (a contextual factor) would moderate the relationships between work status and citizenship. For helping, results demonstrated that preferred status mattered more to part‐time workers than to full‐time. For voice, preferred work status was equally important to part‐time and full‐time workers, such that voice was high only when actual status matched preferred status. Contrary to our expectations, work status made more of a difference in both helping and voice in less bureaucratic organizations. We discuss the implications of work status for social exchange relationships, differences in the social exchange costs and benefits of helping compared to voice, and ramifications of our findings for future research. Copyright © 2001 John Wiley & Sons, Ltd.
Why do ‘great minds’ think alike?: antecedents of team member schema agreement
Authors: Rentsch Joan R. , Klimoski Richard J. 
Published: August 2002

AbstractThe primary contribution of the present study, as implied by the title of this paper, was to delineate and to test antecedents of team member schema agreement and their indirect effects on team effectiveness. The study was conducted in a naturalistic setting involving 315 individuals who comprised 41 teams. Team member teamwork schema agreement was assessed using multidimensional scaling to analyse paired comparison ratings. Demography, team experience, team member recruitment, and team size were significantly related to team member schema agreement, which in turn was significantly related to team effectiveness. Several antecedents were related to team effectiveness indirectly through team member teamwork schema agreement. The results have implications for research on cognition in teams. Copyright © 2001 John Wiley & Sons, Ltd.
Situational constraints on the achievement – performance relationship: a service sector study
Authors: Adkins Cheryl L. , Naumann Stefanie E. 
Published: August 2002

AbstractThe present study sought to extend our knowledge of the relationship between work values and job performance. Situational constraints were examined as moderators of the relationship between the value of achievement and performance in a service‐sector field setting. In the present setting, sales promotions removed situational constraints on performance during three of the six time periods examined. In general, average levels of performance were higher, and there was greater variance in performance when situational constraints were removed. Situational constraints moderated the relationship between the value of achievement and objective performance dimensions, although effect sizes were modest. Further, the present study adds to the small group of studies that have found a direct relationship between achievement and performance in a field setting. Copyright © 2001 John Wiley & Sons, Ltd.
Assessing future changes in extreme precipitation over Britain using regional climate model integrations
Authors: Jones P.D. , Reid P.A. 
Published: August 2002

AbstractIn a changing climate it is important to understand how all components of the climate system may change. For many impact sectors, particularly those relating to flooding and water resources, changes in precipitation intensity and amount are much more important than changes in temperature. This study assesses possible changes in extreme precipitation intensities estimated through both quantile and return period analysis over Britain. Results using a regional climate model (with greenhouse gas changes following the IS92a scenario for 2080–2100) indicate dramatic increases in the heaviest precipitation events over Britain. The results provide information to alter design storm intensities to take future climate change into account, for structures/projects that have long life times. Copyright © 2001 Royal Meteorological Society
El Niño–southern oscillation influences on rice production in Sri Lanka
Authors: Zubair Lareef 
Published: August 2002

AbstractDespite advances in the capacity to predict the evolution of the El Niño–southern oscillation (ENSO) phenomenon and advances in understanding the influence of ENSO on rainfall in tropical regions such as Sri Lanka, there has been limited use of climate predictions for agricultural decision‐making. Climatic fluctuations have a profound influence on the cultivation of crops such as rice, which is the staple food in Sri Lanka. Here, the relationship between the sea‐surface temperature‐based ENSO index of NINO3.4, rainfall and the departure of Sri Lankan rice production from long‐term trends, is analysed for the ‘Maha’ (October to March) and ‘Yala’ (April to September) cultivation seasons between 1952 and 1997.During the El Niño phase, the Maha rice production frequently increased (10 out of 15 seasons) and the Yala production frequently decreased (10 out of 14 seasons). Conversely, during the La Niña phase, the Maha production decreased (seven out of ten seasons) and Yala production increased (six out of eight seasons). Floods, state interventions, civil disturbances, fertilizer price hikes and extreme anomalies in the previous season were noted in the majority of seasons in which these ENSO–production linkages were violated.The correlation of the Maha rice production anomaly with the average NINO3.4 from October to December was significant at the 5% level and that with the aggregate October to December rainfall was significant at the 1% level. Yala rice production showed a significant relationship with concurrent NINO3.4 and a strong correlation (r = 0.60) with the previous season's rainfall. Yala cultivation is water constrained, and carryover storage from the previous season is often used to determine the extent of planting.The relationships between ENSO and seasonal rice production and the relationship between Yala rice production and previous Maha rainfall could be used for agricultural management and policy formulation. Copyright © 2002 Royal Meteorological Society.
Cold and warm events over Argentina and their relationship with the ENSO phases: Risk evaluation analysis
Authors: Rusticucci Matilde , Vargas Walter 
Published: August 2002

AbstractThe main purpose of this work is to provide a broad assessment of the influence of the El Niño–southern oscillation (ENSO) on the frequency of extreme temperature events throughout the year in Argentina. The cold and warm events, defined by the persistence of significant anomalies arising from the maximum and minimum temperatures, are more intense in the subtropical latitudes, north of Argentina (northeast for cold events and northwest for warm events), during the coldest months, and in the south (higher latitudes) in the warmest months. The persistence of the air masses is always greater in the north. The warm (cold) events have a preferential region of dissipation in the northwest (northeast) of Argentina, close to the Andes. The effect of the ENSO phases on the probability of occurrences of these events has a large inter‐monthly variability. The different La Niña episodes are more homogeneous in relation to their effects and feasibility for the prediction of extreme temperatures within the region, especially for cold events. During La Niña episodes, all 2 month periods (except August–September) present a higher occurrence probability of very persistent and intense cold events, compared with Neutral months in different regions of the country. Conversely, the different El Niño episodes are more heterogeneous and, therefore, their effects on temperature are more varied and so less predictable. However, El Niño episodes exhibit a stronger signal, which is associated with the tropical air incursions that generate extreme warm events, particularly in winter. These events have a higher occurrence probability in the north and a lower one in the south during the months of June to November. Cold events have a lower occurrence probability in different regions, during the El Niño phase, in the period April to September. In some cases, the ENSO signal is stronger in daily temperature values than in monthly ones over Argentina. Copyright © 2002 Royal Meteorological Society
Effect of dietary lipid sources on odour‐active compounds in muscle of turbot (Psetta maxima)
Authors: Sérot Thierry , Regost Christelle , Prost Carole , Robin Jean , Arzel Jacqueline 
Published: August 2002

AbstractOdour‐active compounds in muscle of turbot (Psetta maxima) fed experimental diets containing fish oil (FO), soybean oil (SO) or linseed oil (LO) were investigated by a gas chromatography/olfactometry technique. Thirty‐one areas associated with odours were detected in muscle extracts. Among the compounds responsible for these odours, 23 were formed by oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐penten‐1‐ol and (E)‐3‐hexen‐1‐ol contribute strongly to the odour of turbot. (E,Z)‐2,6‐Nonadienal, (E)‐2‐pentenal and (E,E)‐1,3‐(Z)‐5‐octatriene seem to contribute strongly to the odour of turbot fed diets containing high levels of n‐3 PUFA (FO and LO groups). Hexanal and decanal show a high detection frequency in turbot fed diets containing vegetable oils. Odorous compounds which are not formed by lipid oxidation (methional, 1‐acetyl pyrazine, 4‐ethyl benzaldehyde and 2‐acetyl‐2‐thiazoline) were not affected by dietary lipid sources.© 2001 Society of Chemical Industry
An emerging tourism planning paradigm? A comparative analysis between town and tourism planning
Authors: Costa Carlos 
Published: August 2002

AbstractThis article examines the roots and the evolution of tourism and town planning theory and practice. It discusses how both fields have interacted with each other, and provides some clues about the way in which tourism and town planning theory and practice are likely to evolve in the future. It is argued that tourism planning theory is still looking for its own identity and ways of evolving in the future. Copyright © 2001 John Wiley & Sons, Ltd.