bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuronal Cell Death in Hippocampus Induced by Homocysteic Acid in Immature Rats
Authors: Langmeier Miloš , Folbergrová Jaroslava , Haugvicová Renata , Pokorný Jaroslav , Mareš Pavel 
Published: March 2003

Summary:  Purpose: To examine the morphologic alterations in the cerebral cortex and hippocampus of immature rats 6 days after the generalized clonic–tonic seizures induced by homocysteic acid (HCA).Methods: Seizures were induced by bilateral intracerebroventricular infusion of HCA (600 nmol per each side) in 12‐day‐old rats. After 6 days, rat pups were transcardially perfused under deep ether anesthesia with heparinized normal saline and subsequently with the fixation solution (4% paraformaldehyde in phosphate buffer, pH 7.4, for light microscopy) or with Karnovsky's solution (4% paraformaldehyde and 2% glutaraldehyde in phosphate buffer, pH 7.4, for electron microscopic analysis). Nissl stain and the DNA‐specific dye bis‐benzimide (Hoechst 33342) were used.Results: No pathologic changes were found in the cerebral cortex, whereas serious alterations occurred in the hippocampus. A total loss of CA3 pyramidal cells was observed, with marked changes in the CA1 region and dentate gyrus. A prominent glial reaction was seen in many regions of the hippocampal formation. A slight dilatation of the cerebral ventricles was noticed in some experimental as well as control animals. In the granule cell layer of the dentate gyrus, neurons with segmented or fragmented nuclei in various stages of degeneration were detected, displaying the features of apoptotic death.Conclusions: These findings demonstrate the vulnerability of the immature rat brain, which most likely reflects both the direct neurotoxic effect of HCA and prolonged seizure activity. The relative contribution of these two factors still remains to be assessed.
Effects of Topiramate in Two Models of Genetically Determined Generalized Epilepsy, the GAERS and the Audiogenic Wistar AS
Authors: Rigoulot Marie‐Aude , Boehrer Any , Nehlig Astrid 
Published: March 2003

Summary:  Purpose: The antiepileptic effects of topiramate (TPM) were assessed in two models of genetically determined generalized epilepsy. The model of nonconvulsive epilepsy used was a model of absence seizures, the GAERS (Genetic Absence Epilepsy Rat from Strasbourg); and the model of convulsive seizures was an audiogenic rat model, the Wistar Audiogenic Sensitive (AS) rat.Methods: GAERS were equipped with four cortical electrodes over the frontoparietal cortex, and the duration of spike‐and‐wave discharges (SWDs) on the EEG was recorded for periods of 20 to 120 or 300 min. In Wistar AS, the occurrence of, latency to, and duration of one or two wild running episodes and tonic seizures were recorded.Results: In the 16 GAERS studied, TPM (10, 30, and 60 mg/kg) dose‐dependently reduced the expression of SWD that almost totally disappeared at the two highest doses between 40 and 120 min. SWD duration returned to control levels by 180 and 280 min after the injection of 30 and 60 mg/kg TPM, respectively. In Wistar AS, 10 mg/kg TPM induced the occurrence of a second running episode not present in control rats, indicative of a decrease in sensitivity of the rats to the stimulus and increased by 330% the latency to the tonic seizure that still occurred in the eight rats studied. At 30 and 60 mg/kg, the latency to wild running increased by 140%; the second running episode was suppressed in six and seven rats, respectively, whereas the tonic seizure occurred only in one of the eight rats studied at these two doses.Conclusions: These results support the broad spectrum of antiepileptic activity of TPM, confirming its efficacy in primary generalized seizures of both tonic–clonic and of the absence type.
Changes in Nonlinear Signal Processing in Rat Hippocampus Associated with Loss of Paired‐Pulse Inhibition or Epileptogenesis
Authors: Naylor David 
Published: March 2003

Summary:  Purpose: To study acute and chronic physiological effects of perforant path stimulation using paired‐pulse and nonlinear signal analysis techniques (Wiener kernel analysis).Methods: Two to 3‐month‐old Wistar rats were implanted with stimulating electrodes in the perforant path and recording electrodes in the granule cell layer. Loss of paired‐pulse inhibition was produced with 2 Hz continuous and 20 Hz (10 s/min) intermittent stimulation for periods of 1–15 min (0.1 ms, 20 v pulses). Some animals received 30–60 min of stimulation, a model for status epilepticus/epileptogenesis. Responses to paired‐pulse or white noise inputs were recorded sequentially.Results: Loss of inhibition with brief 1–3 min of stimulation, measured by increase paired‐pulse ratio (P2/P1 ISI 40 ms) from 0.25 (±0.27) pre‐ to 1.02 (±0.18) post‐stimulation (p < 0.001), lasted 43 (±15) min. For 30–60 min of stimulation, the paired‐pulse ratios were 0.088 (±0.11), 1.59 (±0.036), 0.06 (±0.11), 0.82 (±0.22) for pre‐, immediate post‐, 1 week post‐, and 1 month poststimulation, respectively (p < 0.025). Compared to prestimulation values, Wiener kernel amplitudes for immediate, 1 week, and 1 month poststimulation were 24% (±13%), 72% (±17%), and 31% (±21%), respectively (p < 0.05). Wiener kernels 1 month poststimulation showed response prolongation with increased opportunity for excitatory interactions of inputs (particularly those separated by 4 ms).Conclusions: Brief perforant path stimulation causes sustained loss of inhibition in the dentate, possibly an early event in the transition to status epilepticus. Stimulation for 30–60 min causes chronic changes in paired‐pulse and white noise (Wiener kernel) responses. Transient recovery occurs by 1 week, but later new features appear (including delayed/late inhibition and potential excitatory cross‐talk) that might favor epileptic seizures.
Die Histopathologie der Helicobacter pylori‐Infektion
Authors: Oberhuber G. , Haidenthaler A. 
Published: March 2003

Zusammenfassung:Praktisch jede Besiedelung mit Helicobacter pylori (H. p.) führt zu einer immunologischen Reaktion der gastralen Mukosa in Form einer chronisch aktiven Gastritis. Nach der Houston‐Überarbeitung der Sydney‐Klassifikation müssen vom Pathologen die durch H. p.‐induzierten histologischen Veränderungen (Grad und Aktivität der Gastritis, intestinale Metaplasie, Atrophie und Besiedelungsdichte von H. p.) semiquantitativ angeben werden. Die Ausprägung der Gastritis in Antrum und Korpus wird vor allem durch das Ausmaß der Säureproduktion bestimmt. Aus bisher ungeklärter Ursache kann bei einem Teil der Patienten der histologische Typ der Gastritis abweichen und eine lymphozytäre Gastritis, eine atrophische Gastritis und eine Riesenfaltengastritis entstehen. Nach Eradikation bleibt ein chronisch entzündliches Infiltrat in der Lamina propria noch jahrelang zurück.
Raltitrexed und Oxaliplatin beim kolorektalen Karzinom: In‐vitro‐ und In‐vivo‐Untersuchungen einer synergistisch wirksamen Zytostatikakombination
Authors: Schüll Birgit , Scheithauer W. 
Published: March 2003

Zusammenfassung: Ziel der vorliegenden Untersuchung war die Prüfung der Wirksamkeit der Kombination von Raltitrexed und Oxaliplatin in vitro unter Verwendung von 4 Kolonkarzinomzellinien und in einem Kollektiv von 36 Patienten mit fortgeschrittenem 5‐FU/Leukovorin ± Irinotecan‐refraktärem Kolonkarzinom.

Im präklinischen Teil wurde die Wirksamkeit von Oxaliplatin und Raltitrexed sowie von 5‐FU jeweils allein bzw. in Kombination mittels MTT‐Test (Microculture Tetrazolium Assay) an 4 verschiedenen etablierten humanen Kolorektalkarzinom‐Zellinien überprüft. Im klinischen Teil wurden 36 Patienten mit fortgeschrittenem kolorektalen Karzinom eingeschlossen, die während bzw. binnen 6 Monate nach dem Erhalt einer palliativen First‐line‐Chemotherapie mit 5‐FU/LV ± Irinotecan eine Tumorprogression aufwiesen. Es wurden Oxaliplatin 130 mg/m2 und Raltitrexed 3,0 mg/m2 am Tag 1 alle 3 Wochen für insgesamt 8 Zyklen bzw. bis zum Nachweis einer Progression verabreicht. Bei der verwendeten In‐vitro‐Zytostatikakonzentration fand sich für die experimentelle Kombination von Oxaliplatin und Raltitrexed bei 3/4 der Zellinien ein supraadditiver Effekt. Bei der klinischen Studie wurde eine partielle Krankheitsremission bei 12 der 36 Patienten (33 %) festgestellt und weitere 17 Patienten (47,2 %) hatten eine Krankheitsstabilisierung. Bei nur 7 Patienten (19,5 %) kam es zur einer Progression. Das mediane progressionsfreie Überleben betrug beachtliche 6,5 Monate und nach einer mittleren Nachbeobachtungsdauer von 12 Monaten waren noch 23 Patienten (64 %) am Leben. Die Verträglichkeit dieser durchwegs ambulant realisierten Behandlung schien akzeptabel, nur bei 8/36 Patienten (22 %) wurde eine WHO‐Grad 3 oder 4 Neutropenie festgestellt. Grad 3 nicht‐hämatologische Nebenwirkungen umfaßten periphere sensorische Neuropathie (3 Pat.), Asthenie (1 Pat.), Diarrhoe (2 Pat.) und Erhöhung der Leberfunktionsproben.  Die Daten zeigen, daß die Kombination von Oxaliplatin und Raltitrexed nicht nur in vitro, sondern auch in vivo und zwar bei Patienten, die unter einer vorangegangenen Therapie mit 5‐FU/LV ± Irinotecan bei fortgeschrittenem kolorektalen Karzinom progredient waren, gute antitumorale Wirksamkeit besitzt. Aufgrund des akzeptablen Toxizitätsprofils und des einfachen Applikationsschemas sollte der therapeutische Stellenwert dieser Kombination beim metastasierten kolorektalen Karzinom im Rahmen nachfolgender prospektiv‐randomisierter Studien weiter überprüft werden.
Introduction of parasitoids has maintained a stable population of arrowhead scales at extremely low levels
Authors: Matsumoto Takashi , Itioka Takao , Nishida Takayoshi , Inoue Tamiji 
Published: March 2003

AbstractWe previously reported the drastic decline of the arrowhead scale,Unaspis yanonensisKuwana (Hemiptera: Diaspididae) following the introduction of two parasitoid species,Aphytis yanonensisDeBach et Rosen andCoccobius fulvusCompere et Annecke (Hymenoptera: Aphelinidae), which were used as biological control agents in a Japanese grove of Satsuma mandarin oranges,Citrus unshiuMarc. (Rutaceae). In this study, we examined whether the parasitoids regulated the scale population at lower levels after its initial decline. Specifically, we monitored the population dynamics of the scale and the rates of parasitism by the two parasitoids three times per year for 16 years following the introduction of the wasps. The two parasitoid species maintained aU. yanonensisdensity at 1/200 of the density prior to their introduction. When we excluded the wasps, the scale population grew at a rate that was more than fivefold that of a control (parasitoid‐infested) group. Although the rates of parasitism byC. fulvusfluctuated, they remained at relatively high levels, whereas those ofA. yanonensiswere 0% over the last 6 years. A repeated‐measures ANOVA indicated that scale density remained stable subsequent to its rapid decline. This showed that the parasitoids stabilized the scale population at a lower level than host plant limitations would have dictated, and strongly suggests thatC. fulvusalone regulates the scale population density at an extremely low level. The latter finding contradicts other studies which have suggested that the two parasitoid species complement each other in regulating scale density. We discuss whether a behavioral refuge used by the scale against parasitoids, which we have demonstrated in an earlier study, might contribute to the observed stable host–parasitoid system at low densities.
Trichoteiromanie
Authors: Reich Stefanie , Trüeb Ralph M. 
Published: March 2003

Zusammenfassung Hintergrund: Unter den physikalischen Schädigungen der Haare, die akzidentell, durch kosmetische Maßnahmen oder durch den Patienten selbst verursacht werden, stellt die Trichotillomanie die häufigste selbst induzierte Form dar. Seltener ist die Trichotemnomanie, bei der die Haare vorsätzlich abgeschnitten werden. Für eine weitere Variante des selbstzugefügten Haarverlustes, bei dem es durch Scheuern und Kratzen am Kapillitium zur Pseudoalopezie kommt, schlugen Freyschmidt‐Paul et al. die Bezeichnung Trichoteiromanie vor. Patienten und Methodik: Vier Patienten mit Trichoteiromanie werden klinisch, morphologisch und psychopathologisch weiter charakterisiert. Ergebnisse: Im Unterschied zur Trichotillomanie finden sich bei der Trichoteiromanie histopathologisch keine diagnostisch wegweisenden Veränderungen, und das Trichogramm fällt normal aus. Auffällig sind als weißliche Haarspitzen imponierende, ausgefranste Haarenden, die lichtmikroskopisch pinselartigen Haarbrüchen entsprechen. Bei allen Patienten fanden sich unterschiedliche zugrundeliegende Störungen. In allen Fällen bestand aber eine Skalpdysästhesie, die nicht auf eine spezifische dermatologische Kopfhauterkrankung zurückzuführen war. Schlußfolgerung: Während die Trichotillomanie psychopathologisch als Störung der Impulskontrolle bzw. Zwangsstörung aufgefaßt wird, handelt es sich bei der Trichoteiromanie um eine weniger einheitliche Störung. Die Kooperation mit einem Psychiater ist angezeigt, insofern als die Therapie und Prognose von der zugrundeliegenden psychopathologischen Störung und ihrer spezifischen psychotherapeutischen und pharmakologischen Behandlung abhängen.
Renewable resources and the gains from trade
Authors: Hannesson Rögnvaldur 
Published: March 2003

The Brander‐Taylor small, open‐economy model of trade in a renewable resource and other goods is modified to allow for diminishing returns in the other goods sector. It is shown that opening up for trade may result in steady‐state gains from trade, even when there is open access to the resource and the country does not specialize fully in resource extraction. It is also shown that transition to optimal management, with price‐taking behaviour, may result in a welfare loss. Resources renouvelables et gains en provenance du commerce international. L'auteur modifie le modèle Brander‐Taylor de commerce international d'une ressource renouvelable et d'autres biens dans le cas d'une petite économie ouverte afin de tenir compte des rendements décroissants dans le secteur des autres biens. On montre que I'ouverture au commerce international peut entraîner des gains en provenance de l'échange international en régime permanent, et ce même quand l'accès à la ressource est ouvert et que le pays ne se spécialise pas dans l'extraction de la ressource. On montre que dans la période de transition vers un management optimal, quand il y a ajustement aux prix de marché, il peut y avoir perte de bien‐être.
Evaluating trade reform with many consumers
Authors: Ju Jiandong , Krishna Kala 
Published: March 2003

In this paper we look at the welfare effects of trade reform in the many‐consumers case. We show that Pareto‐improving reforms with lump‐sum taxation or with non‐lump‐sum taxation are possible in the small country case if sufficient conditions for welfare to rise in the single‐consumer case are met. JEL Classification: F0, F1 Evaluation d'une réforme de la politique commerciale quand il y a plusieurs consommateurs. Les auteurs examinent les effets de bien‐être d'une réforme de la politique commerciale quand il y a plusieurs consommateurs. On montre que des réformes améliorant la situation au sens de Pareto sont possibles grâce à des taxes forfaitaires ou non forfaitaires dans le cas de petits pays si on satisfait les conditions nécessaires pour une amélioration du niveau de bien‐être dans le cas d'un seul consommateur.
Monetary aggregates as indicators of economic activity in Canada: empirical evidence
Authors: Siklos Pierre L. , Barton Andrew G. 
Published: March 2003

Empirical evidence linking monetary aggregates to variables such as inflation and economic growth has weakened over the past two decades. In this study we re‐examine these relationships by creating composite monetary aggregates that switch among existing monetary aggregates, using quarterly data over the sample 1971–99. Overall, composite monetary aggregates appear to be useful in explaining or forecasting short‐run movements in GDP growth and inflation. Also, the most successful composite monetary aggregates produce switch dates that overlap with the introduction of financial innovations. These subsequently prompted the Bank of Canada to revise or introduce new monetary aggregates. JEL Classification: E51, E52, C52, C53 Les agrégats monétaires en tant qu'indicateurs de l'activitééconomique: résultats empiriques. Les résultats empiriques jaugeant les liens entre les agrégats monétaires et des variables telles que l'inflation et la croissance économique montrent que ces liens se sont affaiblis au cours des deux dernières décennies. Ce mémoire examine ces relations en créant des agrégats monétaires composites qui se déplacent entre les agrégats usuels selon certains critères statistiques. L'étude utilise des données trimestrielles pour la période 1971–99. Dans l'ensemble, les agrégats monétaires composites semblent plus utiles pour expliquer ou prévoir les mouvements à court terme dans le niveau de croissance du PIB et de l'inflation. De plus, les agrégats monétaires composites qui ont le plus de succès suggèrent des moments de déplacement qui correspondent à des discontinuités marquant la mise en place d'innovations financières. Celles‐ci ont entraîné la Banque du Canada à reviser les agrégats monétaires usuels ou à en suggérer de nouveaux.
Union suppression and certification success
Authors: Riddell Chris 
Published: March 2003

Over the past decade a number of provinces have abandoned the long‐standing Canadian tradition of automatic certification of unions based on card‐signing and instead opted for mandatory representation voting. This trend, however, has developed with little understanding of the effectiveness of management opposition within a voting regime. In this paper the impact of union suppression on union organizing success within the voting regime of British Columbia is examined. We find that union suppression tactics were highly effective with estimates rivalling those found in the United States. Moreover, results from instrumental variable models suggest that OLS estimates may seriously underestimate the true impact of suppression. Effort de suppression du syndicat et succès dans le processus de certification. Au cours de la dernière décennie, un certain nombre de provinces canadiennes ont abandonné la pratique traditionnelle de certification automatique des syndicats sur la base des signatures de cartes d'adhésion au syndicat, et ont choisi de réclamer un scrutin pour déterminer le support des membres potentiels. On ne comprend pas bien l'efficacité de l'action d'opposition des patrons au syndicat dans ce régime de scrutin. Ce mémoire examine l'impact des efforts de suppression des syndicats sur les succès des syndicats dans leurs efforts d'organisation dans le cadre du régime de scrutin en Colombie Britannique. On découvre que ces tactiques ont été très efficaces, tout autant qu'aux Etats‐Unis. De plus, les résultats obtenus à l'aide de modèles de variables instrumentales montrent que ceux qu'on obtient à l'aide de la méthode des moindres carrés ordinaires peuvent sous‐évaluer l'impact des tactiques de suppression de manière significative.
What impact does the choice of formula have on international comparisons?
Authors: Armstrong Keir G. 
Published: March 2003

In this paper an empirical comparison of a number of alternative multilateral index‐number formulae is undertaken. The magnitude of the effect of choosing one formula over another is ascertained using an appropriate cross‐sectional data set constructed under the auspices of the Eurostat‐OECD Purchasing Power Parity Programme. To this end, a new indicator is proposed that facilitates the measurement of the difference between two sets of bloc consumption shares, each computed using a different multilateral comparison method. JEL Classification: C31, C43, C81, E31, F31, O57 Quel impact est‐ce que le choix des formules a sur les comparaisons internationales? Ce mémoire propose une comparaison empirique d'un certain nombre de formules de nombres‐indices multilatéraux. On tente de jauger la magnitude de l'impact du choix d'une formule plutôt qu'une autre en utilisant une base de données transversales appropriée construite sous l'égide du Programme de parité du pouvoir d'achat Eurostat‐OCDE. On propose un nouvel indicateur qui facilite la mesure de la différence entre deux ensembles de patterns de consommation, chacun calculéà l'aide d'une méthode de comparaison multilatérale différente.
Default Reasoning and Generics
Authors: Cohen Ariel 
Published: March 2003

There are numerous logical formalisms capable of drawing conclusions using default rules. Such systems, however, do not normally determine where the default rules come from; i.e., what it is that makes Birds flya good rule, but Birds drive trucksa bad one.Generic sentences such as Birds fly are often used informally to describe default rules. I propose to take this characterization seriously, and claim that a default rule is adequate if the corresponding generic sentence is true. Thus, if we know that Tweety is a bird, we may conclude by default that Tweety flies, just in case Birds fly is a true sentence.In this paper, a quantificational account of the semantics of generic sentences is presented. It is argued that a generic sentence is evaluated not in isolation, but with respect to a set of relevant alternatives. For example, Mammals bear live young is true because among mammals that bear live young, lay eggs, undergo mitosis, or engage in some alternative form of procreation, the majority bear live young. Since male mammals do not procreate in any form, they do not count. Some properties of alternatives are presented, and their interactions with the phenomena of focus and presupposition is investigated.It is shown how this account of generics can be used to characterize adequate default reasoning systems, and several desirable properties of such systems are proved. The problems of the automatic acquisition of rules from natural language are discussed. Because rules are often explicitly expressed as generics, it is argued that the interpretation of generic sentences plays a crucial role in this endeavor, and it is shown how the theory presented here can facilitate such interpretation.
A Guided Tour through some Extensions of the Event Calculus
Authors: Cervesato Iliano , Franceschet Massimo , Montanari Angelo 
Published: March 2003

Kowalski and Sergot's Event Calculus (EC) is a simple temporal formalism that, given a set of event occurrences, derives the maximal validity intervals (MVIs) over which properties initiated or terminated by these events hold. In this paper, we conduct a systematic analysis of EC by which we gain a better understanding of this formalism and determine ways of augmenting its expressive power. The keystone of this endeavor is the definition of an extendible formal specification of its functionalities. This formalization has the effects of casting determination of MVIs as a model checking problem, of setting the ground for studying and comparing the expressiveness and complexity of various extensions of EC, and of establishing a semantic reference against which to verify the soundness and completeness of implementations.We extend the range of queries accepted by EC, which is limited to Boolean combinations of MVI verification or computation requests, to support arbitrary quantification over events and modal queries. We also admit specifications based on preconditions. We demonstrate the added expressive power by encoding a number of diagnosis problems. Moreover, we provide a systematic comparison of the expressiveness and complexity of the various extended event calculi against each other. Finally, we propose a declarative encoding of these enriched event calculi in the logic programming language λProlog and prove the soundness and completeness of the resulting logic programs.