Amiodarone biokinetics, the formation of its major oxidative metabolite and neurotoxicity after acute and repeated exposure of brain cell cultures.

The difficulty in mimicking nervous system complexity and cell-cell interactions as well as the lack of kinetics information has limited the use of in vitro neurotoxicity data. Here, we assessed the biokinetic profile as well as the neurotoxicity of Amiodarone after acute and repeated exposure in two advanced rodent brain cell culture models, consisting of both neurons and glial cells organized in 2 or 3 dimensions to mimic the brain histiotypic structure and function. A strategy was applied to evidence the abiotic processes possibly affecting Amiodarone in vitro bioavailability, showing its ability to adsorb to the plastic devices. At clinically relevant Amiodarone concentrations, known to induce neurotoxicity in some patients during therapeutic treatment, a complete uptake was observed in both models in 24h, after single exposure. After repeated treatments, bioaccumulation was observed, especially in the 3D cell model, together with a greater alteration of neurotoxicity markers. After 14days, Amiodarone major oxidative metabolite (mono-N-desethylamiodarone) was detected at limited levels, indicating the presence of active drug metabolism enzymes (i.e. cytochrome P450) in both models. The assessment of biokinetics provides useful information on the relevance of in vitro toxicity data and should be considered in the design of an Integrated Testing Strategy aimed to identify specific neurotoxic alerts, and to improve the neurotoxicity assay predictivity for human acute and repeated exposure.

Spontaneous perforation of gallbladder with intrahepatic biloma formation: sonographic signs and correlation with computed tomography

Spontaneous perforation of gallbladder is a severe and infrequent complication of acute cholecystitis that requires early and accurate diagnosis. Concomitant development of intrahepatic collections is rarely observed in such cases. The present report emphasizes the relevance of imaging studies in this setting, describing the typical sonographic and tomographic findings for the diagnosis of such condition.

Brief report : Academic amotivation in light of the dark side of identity formation

The study intended to determine motivational profiles of first-year undergraduates and aimed their characterization in terms of identity processes. First, a cluster analysis revealed five motivational profiles: combined (i.e., high quantity of motivation, low amotivation); intrinsic (i.e., high intrinsic, low introjected and external regulation, low amotivation); "demotivated" (i.e., very low quantity of motivation and amotivation); extrinsic (i.e., high extrinsic and identified regulation and low intrinsic and amotivation); and "amotivated" (i.e., low intrinsic and identified, very high amotivation). Second, using Lebart's (2000) methodology, the most characteristic identity processes were listed for each motivational cluster. Demotivated and amotivated profiles were refined in terms of adaptive and maladaptive forms of exploration. Notably, exploration in breadth and in depth were underrepresented in demotivated students compared to the total sample; commitment and ruminative exploration were under and overrepresented respectively in amotivated students. Educational and clinical implications are proposedand future research is suggested.

Défenses du thérapeute et niveau de formation : une étude exploratoire

Parmi l'ensemble des variables étudiées par la recherche en psychothérapie, le thérapeute en tant que tel semble être le facteur prédictif le plus robuste du processus et des résultats thérapeutiques. Cependant, on ne dispose que de très peu de données de recherche pour expliquer cet effet. Aucune recherche ne s'est intéressée directement aux défenses des psychothérapeutes aux cours d'une psychothérapie. Cette étude poursuit deux objectifs principaux : (1) Évaluer la fréquence absolue des mécanismes de défense utilisés par le thérapeute durant les séances de thérapies et la fréquence relative des différents mécanismes de défense ; (2) évaluer l'effet de la formation à la psychothérapie sur la fréquence des mécanismes de défense du thérapeute. L'échantillon comprend 12 thérapeutes, divisés en 3 catégories : novices, expérimentés (formation terminée), et experts. La thérapie consiste en une intervention psychodynamique brève (IPB) en 4 séances. Les mécanismes de défense du thérapeute ont été mesurés à l'aide des Echelles d'évaluation des mécanismes de défense »), version française du Defense Mechanism Rating Scales (DMRS, Perry et coll., 2004). Les résultats montrent que tous les thérapeutes utilisent plusieurs mécanismes de défense, correspondant à des niveaux de maturité différents. Par ailleurs, les thérapeutes novices n'utilisent pas plus de mécanismes de défense que les thérapeutes plus formés. Enfin le niveau défensif du thérapeute n'a pas d'effet sur le résultat de l'intervention. Cette étude ouvre un champ de recherche prometteur en validant l'intérêt d'étudier les processus de régulation des affects du thérapeute parfois très intenses qui apparaissent au cours de la psychothérapie.

La formulation de cas dans la formation à la psychothérapie. Enjeux pédagogiques du recours à un support filmique.

Un cas exemplaire, un cas d'école, un beau cas, un cas de figure, un cas extrême, un cas particulier, un cas épineux, un cas limite ... Les modalités de l'étude de cas sont multiples et expriment le fait que tout raisonnement suivi, toute explication, toute théorie bute une fois ou l'autre sur la nécessité d'explorer et d'approfondir les propriétés d'une singularité accessible à l'observation. Publier un ouvrage sur la question du cas unique, c'est participer à ce moment de réflexion sur les méthodes scientifiques en psychologie. C'est aussi oeuvrer à un repositionnement constructif de cette modalité de faire science, en donnant la parole aux auteurs spécialistes de ces questions ou directement concernés par celles-ci à travers leurs recherches ou leurs pratiques.

Role of Aeromonas hydrophila flagella glycosylation in adhesion to Hep-2 cells, biofilm formation and immune stimulation.

Polar flagellin proteins from Aeromonas hydrophila strain AH-3 (serotype O34) were found to be O-glycosylated with a heterogeneous heptasaccharide glycan. Two mutants with altered (light and strong) polar flagella glycosylation still able to produce flagella were previously obtained, as well as mutants lacking the O34-antigen lipopolysaccharide (LPS) but with unaltered polar flagella glycosylation. We compared these mutants, altogether with the wild type strain, in different studies to conclude that polar flagella glycosylation is extremely important for A. hydrophila adhesion to Hep-2 cells and biofilm formation. Furthermore, the polar flagella glycosylation is an important factor for the immune stimulation of IL-8 production via toll receptor 5 (TLR5).

El aprendizaje reflexivo en la formación inicial del profesorado: un modelo para aprender a enseñar matemáticas = Reflective learning in the early formation of teachers: a model to learn to teach maths

In this study we analize the application of the reflective learning during initial formation mathematics teachers. This model is based on the sociocultural theories of the human learning and assumes that the interaction and the contrast make possible the coconstruction and the active reconstruction of knowledge.In order to make the study, it was left from a sample of 29 teaching students. The qualitative analysis allowed to identify factors that facilitate the incorporation of the reflective learning in university teaching, as well as the degree of effectiveness of this model to learn to teach mathematics

Studies on formation of chromium niobates

The precise nature of the reaction between chromium chloride and potassium niobate at specific pH levels 12.0, 10.8 and 7.6 has been studied by means of electrometric techniques involving pH and conductometric titrations. The well defined breaks and inflections in the titration curves provide cogent evidence for the formation and precipitation of chromium ortho-Cr2O3.3Nb2 O5, hexa-4Cr2O3.9Nb2 O5 and meta-Cr2O3.3Nb2 O5 niobates in the vicinity of pH 7.5, 6.8 and 5.6, respectively. Analytical investigations of the precipitates have also been carried out which substantiate the results of the electrometric study.

Origem e implicações dos ácidos carboxílicos na atmosfera

A general overview about the ambient levels of low molecular weight carboxylic acids and their possible emission sources, as well as the implication of them in the atmosphere is presented. Carboxylic acids are considered to be one of the dominant classes of organic compounds found in the atmosphere in a variety of phases, such as in rainwater, snow and ice, on aerosol particles and gas phase. They may be originated from biogenic and anthropogenic direct emissions and by photochemical reaction in situ. Emission sources and formation mechanisms of organic acids in the atmosphere are discussed.

The Role of Canyons in Strata Formation

This paper provides a spatial and temporal multi-scale approach of European submarine canyons. We fi rst present the long-term geologic view of European margins as related to controls on submarine canyon development. Then we discuss the extent to which submarine canyon systems resemble river systems because both essentially form drainage networks. Finally, we deal with the hortest-term, highestresolution scale to get a fl avor of the current functioning and health of modern submarine canyons in the northwestern Mediterranean Sea. Submarine canyons are unique features of the seafl oor whose existence was known by European fi shermen centuries ago, especially for those canyons that have their heads at short distance from shoreline. Popular names given to specifi c canyons in the different languages spoken in European coastal communities refer to the concepts of a"deep" or"trench." In the old times it was also common thinking that submarine canyons where so deep that nobody could measure their depth or even that they had no bottom. Submarine canyons are just one of the seven different types of seafl oor valleys identifi ed by Shepard (1973) in his pioneering morphogenetic classifi cation. Shepard (1973) defined submarine canyons as"steep-walled, sinuous valleys, with V-shaped cross sections, and relief comparable even to the largest of land canyons; tributaries are found in most of the canyons and rock outcrops abound on their walls." Canyons are features typical of continental slopes with their upper reaches and heads cut into the continental shelf.

A synthetic approach to palmerolides via Negishi cross coupling. The challenge of the C15-C16 bond formation

The esterification of fragment C1-C8 (2) with fragment C16-C23 (3) to give iodo derivative 4, followed by a Pd-catalysed coupling with a C9-C15 fragment (7 or 8), may provide a common precursor of most palmerolides. Ligands and reaction conditions were exhaustively examined to perform the C15-C16 bond formation via Negishi reaction. With simple models, pre-activated Pd-Xantphos and Pd-DPEphos complexes were the most efficient catalysts at RT. Zincation of the C9-C15 fragment (8) and cross coupling with 4 required 3 equiv of t-BuLi, 10 mol % of Pd-Xantphos and 60 °C.

Emerging, non-PCV13 serotypes 11A and 35B of Streptococcus pneumoniae show high potential for biofilm formation in vitro

Background: Since the use of pneumococcal conjugate vaccines PCV7 and PCV13 in children became widespread, invasive pneumococcal disease (IPD) has dramatically decreased. Nevertheless, there has been a rise in incidence of Streptococcus pneumoniae non-vaccine serotypes (NVT) colonising the human nasopharynx. Nasopharyngeal colonisation, an essential step in the development of S. pneumoniae-induced IPD, is associated with biofilm formation. Although the capsule is the main pneumococcal virulence factor, the formation of pneumococcal biofilms might, in fact, be limited by the presence of capsular polysaccharide (CPS). Methodology/Principal Findings: We used clinical isolates of 16 emerging, non-PCV13 serotypes as well as isogenic transformants of the same serotypes. The biofilm formation capacity of isogenic transformants expressing CPSs from NVT was evaluated in vitro to ascertain whether this trait can be used to predict the emergence of NVT. Fourteen out of 16 NVT analysed were not good biofilm formers, presumably because of the presence of CPS. In contrast, serotypes 11A and 35B formed >45% of the biofilm produced by the non-encapsulated M11 strain. Conclusions/Significance This study suggest that emerging, NVT serotypes 11A and 35B deserve a close surveillance.