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See detailBrain ethanol concentrations and ethanol discrimination in rats : effects of dose and time
Quertemont, Etienne ULg; Green, Heather L.; Grant, Kathleen A.

in Psychopharmacology (2003), 168(3), 262-270

Rationale. In drug discrimination procedures, the substitution pattern for ethanol of various receptor ligands is dependent upon ethanol training dose, presumably reflecting functionally different ... [more ▼]

Rationale. In drug discrimination procedures, the substitution pattern for ethanol of various receptor ligands is dependent upon ethanol training dose, presumably reflecting functionally different concentrations of ethanol in the brain. The discriminative stimulus effects of ethanol are also time-dependent, although very few studies have investigated the time course of ethanol discriminations. Objectives. The present study investigated the relationship between brain ethanol concentrations (BrEC), as measured by intracranial microdialysis of the nucleus accumbens, and the time course of ethanol discriminative effects. Methods. Two groups of rats were trained to discriminate either 1.0 or 2.0 g/kg ethanol from water following a 30-min post-ethanol interval. Following training, the time course of the discriminative stimulus was assessed using a series of abbreviated testing trials at 20-min intervals for 5 h after the administration of various ethanol doses (0, 0.5, 1.0 and 2.0 g/kg). The rats were then fitted with microdialysis probes and the time course of BrECs were determined under conditions similar to the behavioral assessments. Results. BrECs were significantly above zero at 4 min post-gavage and attained peak concentrations of 16 mmol/l, 24 mmol/l and 42 mmol/l at 9 min, 16 min and 95 min after IG administration of 0.5, 1.0 and 2.0 g/kg ethanol, respectively. BrECs were similar in ethanol-naive and ethanol-trained rats, indicating a lack of pharmacokinetic tolerance under these discrimination procedures. The discriminative stimulus effects of ethanol were dose- and time-dependent, with a threshold concentration of approximately 12 mmol/l achieved at 5 min after 1.0 g/kg ethanol gavage in rats trained to discriminate 1.0 g/kg ethanol. Acute tolerance to the discriminative stimulus effects of ethanol was evident from BrECs 2-5 h post-ethanol gavage. Conclusions. Ethanol given intragastrically results in a rapid increase in BrEC, independent of ethanol exposure history. The discriminative stimulus effects of ethanol trained at 30 min post-gavage reflect a specific range of BrEC, and depend on the training dose. These data suggest that qualitatively different stimulus effects of ethanol reflect both different ranges of BrEC, as well as within dose acute tolerance to the discriminative stimulus effects. [less ▲]

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See detailMythe en geschiedenis. De wereld van Paul de Wispelaere
Spinoy, Erik ULg

Book published by VUBPRESS (2003)

This volume contains the revised papers presented at the Paul de Wispelaere conference (Liège, May 2000).

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See detailIsokinetic profile of javelin throwers and relationship to field tests
Forthomme, Bénédicte ULg; Croisier, Jean-Louis ULg; Forthomme, L. et al

in Vlaams Tijdschrift voor Sport Geneeskunde & Sport Wetenschappen (2003), 95

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See detailFeeding behaviour of weaned pigs fed either pellets or meal: effects of the number of aniamls per feeding place
Laitat, Martine ULg; Vandenheede, Marc ULg; Desiron, Alain et al

in Ferrante, V. (Ed.) Proceedings of the 37th International Congress of the International Society for Applied Ethology (2003)

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See detailHistoire de la littérature belge francophone (1830-2000)
Bertrand, Jean-Pierre ULg; Biron, Michel; Denis, Benoît ULg et al

Book published by Fayard (2003)

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See detailLe cocher de Mithra
Swennen, Philippe ULg

in Religious themes and texts of pre-Islamic Iran and Central Asia (Studies in honour of Professor Gherardo Gnoli on the occasion of his 65th birthday on 6th December 2002) (2003)

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See detailRegulation of hypoxia-inducible factor-1alpha protein level during hypoxic conditions by the phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase 3beta pathway in HepG2 cells.
Mottet, Denis ULg; Dumont, Valery; Deccache, Yann et al

in Journal of Biological Chemistry (2003), 278(33), 31277-85

Hypoxia initiates an intracellular signaling pathway leading to the activation of the transcription factor hypoxia-inducible factor-1 (HIF-1). HIF-1 activity is regulated through different mechanisms ... [more ▼]

Hypoxia initiates an intracellular signaling pathway leading to the activation of the transcription factor hypoxia-inducible factor-1 (HIF-1). HIF-1 activity is regulated through different mechanisms involving stabilization of HIF-1alpha, phosphorylations, modifications of redox conditions, and interactions with coactivators. However, it appears that some of these steps can be cell type-specific. Among them, the involvement of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in the regulation of HIF-1 by hypoxia remains controversial. Here, we investigated the activation state of PI3K/Akt/glycogen synthase kinase 3beta (GSK3beta) in HepG2 cells. Increasing incubation times in hypoxia dramatically decreased both the phosphorylation of Akt and the inhibiting phosphorylation of GSK3beta. The PI3K/Akt pathway was necessary for HIF-1alpha stabilization early during hypoxia. Indeed, its inhibition was sufficient to decrease HIF-1alpha protein level after 5-h incubation in hypoxia. However, longer exposure (16 h) in hypoxia resulted in a decreased HIF-1alpha protein level compared with early exposure (5 h). At that time, Akt was no longer present or active, which resulted in a decrease in the inhibiting phosphorylation of GSK3beta on Ser-9 and hence in an increased GSK3beta activity. GSK3 inhibition reverted the effect of prolonged hypoxia on HIF-1alpha protein level; more stabilized HIF-1alpha was observed as well as increased HIF-1 transcriptional activity. Thus, a prolonged hypoxia activates GSK3beta, which results in decreased HIF-1alpha accumulation. In conclusion, hypoxia induced a biphasic effect on HIF-1alpha stabilization with accumulation in early hypoxia, which depends on an active PI3K/Akt pathway and an inactive GSK3beta, whereas prolonged hypoxia results in the inactivation of Akt and activation of GSK3beta, which then down-regulates the HIF-1 activity through down-regulation of HIF-1alpha accumulation. [less ▲]

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See detailRedefining the role of psr in beta-lactam resistance and cell autolysis of Enterococcus hirae.
Sapunaric, Frédéric ULg; Franssen, Christine; Stefanic, Patrick et al

in Journal of Bacteriology (2003), 185(20), 5925-35

The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the beta-lactam resistance, growth, and cell autolysis of wild-type strain ATCC 9790 and resistant strain ... [more ▼]

The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the beta-lactam resistance, growth, and cell autolysis of wild-type strain ATCC 9790 and resistant strain R40 of Enterococcus hirae was investigated by disruption or substitution of the corresponding pbp5 and psr genes by Campbell-type recombination. The resulting modifications were confirmed by hybridization and PCR. The low susceptibility of E. hirae to beta-lactams was confirmed to be largely dependent on the presence of PBP5. However, against all expectations, inactivation of psr in ATCC 9790 or complementation of R40 cells with psr did not modify the susceptibility to benzylpenicillin or the growth and cell autolysis rates. These results indicated that the psr gene does not seem to be involved in the regulation of PBP5 synthesis and consequently in beta-lactam resistance or in the regulation of cell autolysis in E. hirae. [less ▲]

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See detailInfection parl'herpèsvirus de la chèvre
Thiry, Etienne ULg; Engels, M.

in Lefèvre, P. C.; Blancou, Jean; Chermette, R. (Eds.) Principales maladies infectieuses et parasitaires du bétail, Europe et régions chaudes, généralités, maladies virales (2003)

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See detailLes onychomycoses--echec et mat?
Arrese Estrada, Jorge ULg; Quatresooz, Pascale ULg; Pierard, Claudine ULg et al

in Revue Médicale de Liège (2003), 58(9), 559-62

According to individuals, onychomycoses or their treatments can be held in check. Some of the "promises" sometimes offered by pharmaceutical companies are not fully kept and hopes of cure may remain wild ... [more ▼]

According to individuals, onychomycoses or their treatments can be held in check. Some of the "promises" sometimes offered by pharmaceutical companies are not fully kept and hopes of cure may remain wild. Some special therapeutic strategies should be employed in case of recalcitrant or recurrent onychomycosis. [less ▲]

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See detailSexual interactions in triadic encounters involving paedomorphic and metamorphic Alpine newts Triturus alpestris
Denoël, Mathieu ULg

Poster (2003)

Sexual selection theories suppose that morphologically-contrasting alternative morphs may exhibit different mating tactics. Facultative paedomorphosis in newts is a suitable process to explore this ... [more ▼]

Sexual selection theories suppose that morphologically-contrasting alternative morphs may exhibit different mating tactics. Facultative paedomorphosis in newts is a suitable process to explore this question because it implies the coexistence of two morphs differing by the presence of gills and epigamic traits. The aim of this study was to find out whether paedomorphs (i.e. adult retaining larval traits) and metamorphs use similar behavioural patterns to attract mates in the presence of a rival and whether there are differences in sexual activity and success between alternative morphs. Sexual interactions in triadic encounters were staged and analysed in a standardised experimental design. The two kinds of males did not differ in terms of sexual activity, spermatophore deposition or female responsiveness. Both rival paedomorphic and metamorphic males exhibited sexual interference, but in most encounters, intruders just disturbed the courting pair. Sperm transfer success was lower in triadic encounters than in dyadic encounters. These results illustrate that inter-morph breeding also occurs in the presence of competitors, but that the success rate of the newts is considerably decreased in such competitive situations. Moreover, newts do not use alternative reproductive tactics depending of their status (i.e. paedomorph or metamorph). [less ▲]

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See detailFuguer: ... pour fuir quoi ? Étude sur le profil et le vécu des fugueurs en Belgique
Van de Water, G.; Vettenburg, N.; Glowacz, Fabienne ULg

Book published by Ed. Fondation Roi Baudouin (2003)

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See detailLa Motivation. Comprendre et agir.
Chenu, Florent ULg; Crepin, Françoise ULg; Jehin, Monique ULg

Learning material (2003)

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See detailLarge phosphorus hyperfine coupling as a sensitive tool for studying molecular dynamics : ESR and Molecular Mechanics studies of ring interconversion in cis-2,5-diphosphoryl-2,5-dimethyl-pyrrolidinoxyl radical
Rockenbauer, Antal; Gaudel-Siri, Anouk; Siri, Didier et al

in Journal of Physical Chemistry A (2003), 107(19), 3851-3857

ESR spectra of cis- and trans-â-diphosphorylated pyrrolidine-N-oxyl radicals, c-1 and t-1, were studied in liquid and frozen solution. The expected 1:2:1 triplet (aP (2)) of the 1:1:1 triplet (aN) was ... [more ▼]

ESR spectra of cis- and trans-â-diphosphorylated pyrrolidine-N-oxyl radicals, c-1 and t-1, were studied in liquid and frozen solution. The expected 1:2:1 triplet (aP (2)) of the 1:1:1 triplet (aN) was observed for t-1; however, for c-1, the inner lines of the 1:2:1 triplet showed a dramatic broadening characteristic of chemical exchange between two equivalent conformations. Owing to the large difference in the hyperfine splitting constants (hfsc) of the exchanging phosphorus (¢aP 21 G), the coalescence temperature was unusually high (193 K, in n-pentane), and the potential barrier for ring interconversion (10.5 kJ mol-1) was easily obtained from the temperature dependence of the exchange rate. This value was in very good agreement with the value obtained for an empirical pseudorotational potential (11 kJ mol-1) that was adjusted to fit the temperature dependence of the phosphorus hfsc. For c-1, molecular mechanics calculations gave similar characteristics for the pseudorotational potential and indicated the existence of two identical minima with distorted geometries lying between 3T4 and 3E or 4T3 and E3. For t-1, only the 3T4 conformer was found to be significantly populated. Frozen solution spectra showed that the phosphorus hfsc anisotropy is higher when the C-P bond is pseudoaxial; this result can be explained by a geometry-dependent delocalization of the unpaired electron into the phosphorus 3p orbitals. [less ▲]

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See detailUne méthode générique pour la classification automatique d'images à partir des pixels
Marée, Raphaël ULg; Geurts, Pierre ULg; Wehenkel, Louis ULg

in Revue des Nouvelles Technologies de l'Information (2003), 1

Dans cet article, nous évaluons une approche générique de classification automatique d'images. Elle repose sur une méthode d'apprentissage récente qui construit des ensembles d'arbres de décision par ... [more ▼]

Dans cet article, nous évaluons une approche générique de classification automatique d'images. Elle repose sur une méthode d'apprentissage récente qui construit des ensembles d'arbres de décision par sélection aléatoire des tests directement sur les valeurs basiques des pixels. Nous proposons une variante, également générique, qui réalise une augmentation fictive de la taille des échantillons par extraction et classification de sous-fenêtres des images. Ces deux approches sont évaluées et comparées sur quatre bases de données publiques de problèmes courants: la reconnaissance de chiffres manuscrits, de visages, d'objets 3D et de textures. [less ▲]

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See detailSpinal mechanisms contribute to analgesia produced by epidural sufentanil combined with bupivacaine for postoperative analgesia
Joris, Jean ULg; Jacob, Eric; Sessler, Daniel et al

in Anesthesia and Analgesia (2003), 97

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