bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Expression of GABA and Glutamate‐receptor Subunits and Enzymes Involved in GABA Metabolism between Electrophysiologically Identified Hippocampal CA1 Pyramidal Cells and Interneurons
Authors: Telfeian Albert E. , Tseng Henry C. , Baybis Marianna , Crino Peter B. , Dichter Marc A. 
Published: March 2003

Summary:  Purpose: The balance between synaptic excitation and inhibition within the hippocampus is critical for maintaining normal hippocampal function. Even mild reduction in inhibition or enhancement of excitation can produce seizures. Synaptic excitation is produced by pyramidal cells and granule cells, whereas inhibition is produced by a smaller number of interneurons. To understand how two subpopulations of these excitatory and inhibitory neurons are regulated at the molecular level, we analyzed specific mRNA expression profiles for receptors that are significantly involved in synaptic transmission and in the synthesis and storage of the principal inhibitory neurotransmitter, γ‐aminobutyric acid (GABA). Our hypothesis was that differences in gene expression between inhibitory and excitatory neurons in the rat hippocampus might point to specific new targets for seizure pharmacotherapy.Methods: We combined the techniques of (a) whole‐cell patch clamping in rat hippocampal slices, (b) biocytin staining for cell identification, (c) single‐cell mRNA amplification, and (d) small‐scale cDNA microarray analysis to allow us to obtain expression profiles for candidate genes from identified CA1 pyramidal neurons and interneurons. Electrophysiologic and morphologic data and expression profiles were obtained from 12 stratum pyramidale and seven stratum radiatum cells.Results: Presumed inhibitory neurons expressed significantly more GAD65, GAD67, vGAT, GABAA‐receptor α3, and N‐methyl‐d‐aspartate (NMDA)‐receptor IIB mRNA, and presumed excitatory neurons expressed more GABAA‐receptor α1, and NMDA‐receptor I mRNA.Conclusions: Differential expression of candidate neurotransmitter‐receptor subunits distinguished CA1 pyramidal neurons from interneurons. These differences may indicate potential new targets for altering the balance of inhibition and excitation in the treatment of epilepsy.
Mesial Temporal Sclerosis in Acute Childhood Leukemias
Authors: Goyal Monisha , Bangert Barbara A. , Wiznitzer Max 
Published: March 2003

Summary:  Purpose: Although seizures are relatively common in acute childhood leukemias, evolution into epilepsy is rare.Methods: We describe three patients with acute leukemias who received chemotherapy. One patient also received cranial irradiation.Results: All three developed recurrent complex partial seizures after initiation of chemotherapy. Initial neuroimaging performed in two patients was normal. Subsequent neuroimaging in all three revealed mesial temporal sclerosis.Conclusions: The association of mesial temporal sclerosis in acute childhood leukemias has not been previously described and may be secondary to antileukemic treatment and recurrent seizures.
Lateralising Value of Neuropsychological Protocols for Presurgical Assessment of Temporal Lobe Epilepsy
Authors: Akanuma Nozomi , Alarcón Gonzalo , Lum Francis , Kissani Najib , Koutroumanidis Michael , Adachi Naoto , Binnie Colin D. , Polkey Charles E. , Morris Robin G. 
Published: March 2003

Summary:  Purpose: To estimate the value of neuropsychological measurements in determining the side of seizure onset for presurgical assessment in patients with temporal lobe epilepsy. The lateralising value of neuropsychological protocols was evaluated for all patients and in subpopulations depending on surgical outcome with regard to seizure control, speech dominance, neuropathology, and need for intracranial EEG recordings.Methods: A battery of neuropsychological procedures was carried out preoperatively in 125 patients who underwent left (n = 66) or right (n = 59) temporal lobectomies. Binary logistic regression analysis was performed to find sets of variables that allowed the best prediction of the side of seizure onset (assumed to be the operated‐on side).Results: Combinations of noninvasive neuropsychological tests and Wada subscores showed the highest lateralising values: 80.8% for all patients, 79.4% in seizure‐free patients, 86.0% in patients not rendered seizure free, 85.7% in left speech patients, 77.8% in non–left speech patients, 89.3% in patients with mesial temporal sclerosis (MTS), 78.1% in non‐MTS patients, 80.3% in patients who underwent intracranial EEG recordings, and 77.3% in those who did not.Conclusions: The lateralising value (80‐90%) of neuropsychological protocols appears similar to that of other tests widely accepted for lateralisation (ictal and interictal scalp EEG and neuroimaging). Attention should be paid to neuropsychological results, particularly from the Wada test, during presurgical assessment of temporal lobe epilepsy, as they can provide strong support for findings from other lateralising tests, particularly in patients with presumed MTS or in left‐speech patients.
Epileptogenesis After Self‐Sustaining Status Epilepticus
Authors: Mazarati Andrey , Bragin Anatol , Baldwin Roger , Shin Don , Wilson Charles , Sankar Raman , Naylor David , Engel Jerome , Wasterlain Claude G. 
Published: March 2003

Summary:  Purpose: To describe the natural history of chronic epilepsy after experimental self‐sustaining status epilepticus (SSSE) and to correlate patterns of SSSE with ictal, interictal, and plastic changes that characterize chronic epilepsy.Methods: SSSE was induced in adult Wistar rats by 30‐min intermittent electrical stimulation of the perforant path. In some animals, SSSE was treated by short‐term administration of antiepileptic drugs (AEDs). After SSSE, EEG and animal behavior were monitored for ≤1 year. Some animals were killed to study mossy fiber sprouting in the dentate gyrus.Results: Despite the high reproducibility of the electrographic and behavioral manifestations of SSSE, patterns of chronic epilepsy varied considerably among animals in terms of seizure frequency, initial seizure pattern at the onset of chronic epilepsy, and frequency of interictal spikes. Statistically significant correlations were found between spike frequency during SSSE and interictal spike frequency, as well as between the frequency of spontaneous seizures and degree of mossy fiber sprouting. Early treatment of SSSE prevented the occurrence of spontaneous seizures and significantly decreased frequency of interictal spikes. Late treatment of SSSE did not prevent spontaneous seizures, but significantly decreased their frequency, and eventually may lead to remission of epilepsy.Conclusions: SSSE leads after a “silent” period to chronic epilepsy, which is maintained for ≥1 year in the rat. The silence is only behavioral, because EEG paroxysmal activity is seen in every animal. In this model of SSSE, the timing of treatment is a major determinant of outcome. Early treatment reduces the incidence of chronic epilepsy, whereas late treatment only reduces its severity. The possibility that this reduction of the severity of epilepsy may led to spontaneous remissions merits further study.
Seizures Decrease Postnatal Neurogenesis and Granule Cell Development in the Human Fascia tDentata
Authors: Mathern Gary W. , Leiphart James L. , De Vera Adelaine , Adelson P. David , Seki Tatsunori , Neder Luciano , Leite Joao P. 
Published: March 2003

Summary:  Purpose: There is considerable controversy whether childhood seizures damage existing neurons and/or adversely affect neurogenesis and synaptogenesis. This study addressed this question by examining fascia dentata neurogenesis, cell death, and aberrant axon connections in hippocampi from children with extratemporal seizure foci.Methods: Surgically resected (n = 53) and age‐comparable autopsy (n = 22) hippocampi were studied for neuronal densities, polysialic acid (PSA) neural cell adhesion molecule (NCAM) immunoreactivity (IR), TUNEL, and neo‐Timm's histochemistry.Results: Compared with autopsy cases, hippocampi from children with frequent seizures showed (a) decreased fascia dentata granule cell densities; (b) decreased PSA NCAM IR cell densities in the stratum granulosum, infragranular, and hilar regions; (c) no positive TUNEL‐stained cells; and (d) aberrant supragranular mossy fiber axon connections.Conclusions: These results indicate that severe seizures during early childhood are associated with anatomic signs of decreased postnatal granule cell neurogenesis (PSA NCAM IR) and aberrant mossy fiber axon connections (neo‐Timm's) without evidence of seizure‐induced cell death (TUNEL). In humans, these results support the concept that seizures do not damage existing neurons, but adversely affect processes involved with normal postnatal neuronal development such as neurogenesis and axon formation. Such alterations probably negatively affect normal brain development, and/or promote epileptogenesis.
Estrogen Treatment Protects GABAB Inhibition in the Dentate Gyrus of Female Rats after Kainic Acid–Induced Status Epilepticus
Authors: Velíšek Libor , Velíšková Jana 
Published: March 2003

Summary:  Purpose: We used the paired‐pulse inhibition paradigm to determine whether the cell loss in the hilus of the dentate gyrus of female rats after kainic acid (KA)‐induced status epilepticus (SE) is associated with functional changes in the dentate gyrus. Additionally, we determined whether the lost function could be preserved by using estrogen neuroprotection.Methods: Female rats were ovariectomized and treated either with estrogen replacement (four doses of 2 μg of estradiol every 24 h: two doses before SE, two doses after) or oil. SE was induced by I.P. administration of KA (16 mg/kg) and terminated after 5 h with pentobarbital. After 2 days, hippocampal/dentate gyrus slices were prepared. Population spikes were recorded in the granule cell layer as a response to mixed perforant‐path stimulation (10‐ to 1,000‐ms interstimulus intervals). Ratios of the test response to conditioning response were evaluated. γ‐Aminobutyric acid type B (GABAB) receptors were blocked with 400 μM CGP 35348.Results: In slices from oil‐treated rats, SE induced a loss of paired‐pulse inhibition in the dentate gyrus at the interstimulus intervals marking intermediate facilitation and late depression. There was no such loss of paired‐pulse inhibition in estrogen‐treated rats. CGP 35348 was unable to alter paired‐pulse inhibition in slices form oil‐treated rats. In slices from estrogen‐treated rats, CGP decreased paired‐pulse inhibition at 50–150‐ms interstimulus intervals. Comparison of paired‐pulse inhibition in slices from oil‐treated rats with slices from estrogen‐treated rats with CGP 35348 revealed a GABAB‐independent difference at interstimulus intervals >300 ms.Conclusions: Our study demonstrated that there is a complete loss of GABAB receptor–mediated inhibition after KA‐induced SE in the dentate gyrus. Pretreatment with estrogen can save GABAB‐receptor function, probably by neuroprotection of neurons containing the postsynaptic GABAB receptors.
Extracellular Matrix Components are Altered in the Hippocampus, Cortex, and Cerebrospinal Fluid of Patients with Mesial Temporal Lobe Epilepsy
Authors: Perosa S. R. , Porcionatto M. A. , Cukiert A. , Martins J. R. M. , Amado D. , Nader H. B. , Cavalheiro E. A. , Leite J. P. , Naffah‐Mazzacoratti M. G. 
Published: March 2003

Summary:  Purpose: This work studied the profile of glycosaminoglycans (GAGs) in the hippocampus, cortex, and cerebrospinal fluid of patients with temporal lobe epilepsy (TLE).Methods: The GAGs were analyzed by agarose gel electrophoresis, enzymatic degradation, and enzyme‐linked immunosorbent assay (ELISA).Results: The hippocampus of TLE patients showed increased levels of chondroitin sulfate and hyaluronic acid against normal levels of these GAGs in the neocortex and cerebrospinal fluid (CSF).Conclusions: These results suggest that these matrix components could be involved in the pathophysiology of TLE.
Determinants of Ictal Epileptiform Patterns in the Hippocampal Slice
Authors: Rutecki Paul A. , Sayin Umit , Yang Yili , Hadar Eldad 
Published: March 2003

Summary:  Purpose: The transition from an interictal to an ictal pattern of epileptiform activity is a strategic target for antiepileptic drug (AED) action. Both the muscarinic agonist pilocarpine and the selective group I metabotropic glutamate receptor (mGluR) agonist (RS)‐3,5‐dihydroxyphenylglycine (DHPG) produce prolonged synchronous activity in the hippocampal slice that resembles ictal discharges. We evaluated the role of synaptic mechanisms and release of calcium from intracellular stores in the generation of prolonged ictal oscillations.Methods: Pilocarpine (10 μM) in 7.5 mM[K+]o or DHPG (100 μM) in 5 mM[K+]o artificial cerebrospinal fluid (ACSF) were bath applied to hippocampal slices, and extracellular recordings were made from the CA3 region. The pattern of activity was characterized as ictal if prolonged oscillations of discharges occurred at >2 Hz lasting for >3 s. The pattern of epileptiform activity was characterized and compared with the pattern observed after bath application of pharmacologic agents.Results: The AMPA/kainic acid (KA) glutamate receptor blocker DNQX (20 μM) dampened and stopped ictal oscillations; however, antagonism of N‐methyl‐d‐aspartate (NMDA) or γ‐aminobutyric acid (GABAA) receptors had minimal effects on ictal patterns. Ictal discharges were suppressed by dantrolene (30–100 μM), which blocks release of calcium from intracellular stores, or thapsigargin (1–5 μM), which inhibits the adenosine triphosphatase (ATPase) that maintains intracellular calcium stores. The L‐type calcium channel antagonist nifedipine (1 μM) blocked ictal activity produced by pilocarpine or DHPG.Conclusions: Ictal discharges produced by pilocarpine or DHPG depended on intact synaptic transmission mediated by AMPA/KA receptors, release of calcium from intracellular stores, and L‐type calcium channel activation. The results suggest that muscarinic and group I mGluRs activate a positive‐feedback system that creates calcium oscillations and prolonged neuronal synchronization mediated by recurrent excitatory synaptic connections in the CA3 region of the hippocampus.
Involvement of the Neuropeptide Orphanin FQ/Nociceptin in Kainate and Kindling Seizures and Epileptogenesis
Authors: Bregola G. , Zucchini S. , Frigati L. , Candeletti S. , Romualdi P. , Reinscheid R. , Simonato M. 
Published: March 2003

Summary:  Purpose: To investigate the role of orphanin FQ/nociceptin (OFQ/N) in epilepsy, we analyzed (a) proOFQ/N (the OFQ/N precursor) and ORL‐1 (the OFQ/N receptor) messenger RNA (mRNA) levels in the kainate and in the kindling models of epilepsy in the rat; and (b) seizure expression in proOFQ/N knockout mice.Methods: Epilepsy models: kainate and kindling. Northern blot analysis, radioactive in situ hybridization.Results: Increased proOFQ/N mRNA levels were found in the thalamus (reticular nucleus) after kainate administration. In contrast, ORL‐1 gene expression decreased dramatically in the amygdala, hippocampus, thalamus, and cortex after kainate administration. OFQ/N knockout mice displayed reduced susceptibility to kainate‐induced seizures, in that (a) lethality was reduced, (b) latency to generalized seizure onset was significantly prolonged, and (c) behavioral seizure scores were significantly reduced. Furthermore, kindling progression was delayed in OFQ/N–/– mice.Conclusions: These data indicate that limbic seizures are associated with increased OFQ/N release in multiple brain areas, causing downregulation of ORL‐1 receptors and activation of OFQ/N biosynthesis in selected areas, and support the notion that the OFQ/N‐ORL‐1 system may play a facilitatory role in ictogenesis and in epileptogenesis.
Effect on Epileptogenesis of Carbamazepine Treatment During the Silent Period of the Pilocarpine Model of Epilepsy
Authors: Capella H. M. , Lemos T. 
Published: March 2003

Summary:  Purpose: This study addresses the question of epileptogenesis by investigating the effects of carbamazepine (CBZ) on the silent period of the pilocarpine model of epilepsy.Methods: Adult Wistar rats were subjected to status epilepticus (SE) induced by pilocarpine and treated with CBZ or saline, i.p, during 56 days. Latency for the first spontaneous seizure, incidence, frequency, and duration of seizures were monitored for ≤56 days after treatment. Hippocampal histologic analysis was performed.Results: CBZ reduced the frequency and duration of the seizures and the hippocampal damage.Conclusions: CBZ did not abort the epileptogenesis but minimized the expression of seizures and hippocampal damage.
Functional and Morphological Changes in the Hippocampal Neuronal Circuits Associated with Epileptic Seizures
Authors: Maru Eiichi , Kanda Masutaro , Ashida Hiroshi 
Published: March 2003

Summary:  Purpose: We review what is currently known about functional and morphologic plasticity of hippocampal neuronal circuits in animal epilepsy models.Results: Perforant‐path kindling has been shown to enhance excitatory synaptic transmission in the dentate gyrus significantly, and this enhancement has lasted for ≥1 month after kindling. However, in our rapid kindling experiment with an interstimulus interval of 5 min, perforant‐path kindling resulted in behavioral convulsions and prolonged the afterdischarge duration, but dentate synaptic transmission remained depressed during kindling.Conclusions: These results indicate that kindling‐induced synaptic potentiation is not necessary for kindling development. Conversely, epileptic seizures have led to the anomalous sprouting of mossy fibers, a process thought to induce hyperexcitation of granule cells. We conclude that the sprouting of mossy fibers did not play a critical role in kindling, because we observed no significant correlation between the mossy fiber sprouting and kindling development. Epileptic seizures also have been shown to increase γ‐aminobutyric acid (GABA)A receptor–mediated inhibition during interictal periods. Although this strengthening of GABAergic inhibition is likely to be a defensive measure against seizure initiation, some studies have suggested that another type of GABAergic response facilitates seizure activity. The possibility of GABAA receptor–mediated excitation during ictal periods is theoretically examined.
Effects of potato plants expressing the nptII‐gus fusion marker genes on reproduction, longevity, and host‐finding of the peach‐potato aphid, Myzus persicae
Authors: Alla Salah , Cherqui Anas , Kaiser Laure , Azzouz Hichem , Sangwann‐Norreel Brigitte S. , Giordanengo Philippe 
Published: March 2003

AbstractTransgenesis developed in the last 20 years offers new possibilities for crop protection. The transgenic process, however, requires the use of marker fusion genes to select and visualize the transformed tissues. Although the expression products of these marker genes are stably expressed in crops, little attention has been given to assess the eventual risks of these recombinant proteins on phytophage populations. Three independent transgenic potato (Solanum tuberosum) clones from the cultivar Désirée (DG5, DG18, and DG20) carrying the commonly used nptII‐gus gene construct and exhibiting different β‐glucuronidase activity (0.843 ± 0.011, 0.576 ± 0.096, and 0.002 ± 0.000 pmol min−1.mg−1, respectively) were evaluated to determine the impact of the encoded proteins on the behaviour, development, reproduction, and demography of the peach‐potato aphid, Myzus persicae, under laboratory‐controlled light and temperature. Our results revealed that the transgenic event can alter aphid physiology or behaviour. Experiments showed a probiotic effect of one transgenic line, the DG5, resulting in reduced prereproductive period and mortality, and enhanced daily fecundity, which was expressed in a greater population growth potential (rm = 0.205 vs. rm = 0.174 of the control). In contrast, aphids fed with the DG18 line exhibited reduced adult survival and reproductive period but no alteration of their demographic parameters (rm = 0.176). Finally, no physiological alteration was induced in aphids fed on a DG20 diet (rm = 0.170). Behavioural experiments conducted in a 4‐choice olfactometer demonstrated that insects were significantly more attracted by the odour of transgenic DG18 potato plant than that of Désirée non‐transformed plant, spending twice as much time in the DG18 plant odour. The two other transformed clones (DG5 and DG20) were as attractive as the non‐transformed cultivar. It is concluded that the β‐glucuronidase expression in potato plants might be responsible for the probiotic effect measured on the feeding aphids, whereas alteration of the foliage odour would result from a pleiotropic effect.
Distributional dynamics following a technological revolution
Authors: Andolfatto David , Smith Eric 
Published: March 2003

In this paper we explore the link between technological change and the dynamics of employment, production, and the distribution of earnings. Technological change not only advances society's collective capability but also changes the relative productivities of its members. The latter effect establishes the likely winners and losers from advances in productive capabilities, provides a mechanism that can generate cyclical fluctuations in output as well as employment, and determines the evolution of the earnings distribution. Dynamique de la répartition à la suite d'une révolution technologique. Ce mémoire examine le lien entre le changement technologique et la dynamique de l'emploi, de la production et de la répartition des revenus. Le changement technologique n'augmente pas seulement la capacité collective d'une société mais modifie aussi les productivités relatives de ses membres. Ce dernier effet crée des gagnants et des perdants, déclenche un mécanisme qui peut générer des fluctuations cycliques tant dans le niveau de production que dans celui de l'emploi, et détermine l'évolution de la répartition des revenus.
Product differentiation, competition, and international trade
Authors: Bernhofen Daniel M. 
Published: March 2003

In this paper the two workhorse theories of international trade under imperfect competition – Krugman’s taste for variety model and Brander’s strategic intra‐industry trade model – are integrated into a single analytical framework. A quadratic utility function allows for a nesting of these two theories by postulating a consumer taste for variety over differentiated products, where the extent of product differentiation is linked to the intensity of strategic interaction among firms. The model yields intuitive predictions on the effects of the degree of product differentiation on the volume of trade and on the composition of the gains from trade under imperfect competition. JEL classification: F12 Différenciation de produits, concurrence et commerce international. Ce mémoire intègre deux théories connues du commerce international en régime de concurrence imparfaite – le modèle du goût pour la variété de Krugman et celui du commerce intra‐industrie de Brander – en un seul cadre analytique. Une fonction d’utilité quadratique permet d’encadrer ces deux théories en postulant que le consommateur a un goût pour la variété dans une gamme de produits différenciés où le degré de différenciation est reliéà l’intensité de l’interaction stratégique entre les entreprises. Le modèle engendre des prévisions quant aux effets du degré de différenciation des produits sur le volume de commerce international et la composition des gains résultant de ce commerce en régime de concurrence imparfaite.