The Neural Correlates of Spatial and Object Working Memory in Elderly and Parkinson’s Disease Subjects

This fMRI study deals with the neural correlates of spatial and objects working memory (SWM and OWM) in elderly subjects (ESs) and idiopathic Parkinson’s disease (IPD). Normal aging and IPD can be associated with a WM decline. In IPD population, some studies reported similar SWM and OWM deficits; others reported a greater SWM than OWM impairment. In the present fMRI research, we investigated whether compensated IPD patients and elderly subjects with comparable performance during the execution of SWM and OWM tasks would present differences in WM-related brain activations. We found that the two groups recruited a prevalent left frontoparietal network when performing the SWM task and a bilateral network during OWM task execution. More specifically, the ESs showed bilateral frontal and subcortical activations in SWM, at difference with the IPD patients who showed a strict left lateralized network, consistent with frontostriatal degeneration in IPD. The overall brain activation in the IPD group was more extended as number of voxels with respect to ESs, suggesting underlying compensatory mechanisms. In conclusion, notwithstanding comparable WM performance, the two groups showed consistencies and differences in the WM activated networks. The latter underline the compensatory processes of normal typical and pathological aging

Cultures d'hybridomes : production d'anticorps monoclonaux, étude de l'apoptose et application à la toxicité de surfactifs

Not availableLa production d'anticorps monoclonaux par des cultures d'hybridomes peut être optimisée en utilisant des milieux sans-sérum ou en effectuant des cultures en masse. Par ailleurs, la production d'anticorps peut être améliorée en maintenant les cultures en vie pendant des temps de plus en plus longs. Ceci nous a donc amené à étudier la mort des cellules par apoptose et nécrose. Trois hybridomes différents (A49, A64 et B146) ont été adaptés à plusieurs types de milieux sans sérum suivant une technique dite d'adaptations lentes. Nous décrivons ensuite un autre type d'adaptations qui ont été réalisées en un temps plus court: adaptations rapides. Nous avons, par ailleurs, comparé trois hybridomes (AFRC MAC 65, HF2 x 653 et OX 19) dans 3 systèmes de culture différents (boites, flacons à agitation et systèmes comportant des tubes à dialyse), en observant leur croissance et l'état du matériel génétique (empreinte digitale et fragmentation de l'ADN). Un certain nombre d'expériences complémentaires ont été réalisées afin de tester les propriétés du système de culture à base de tubes à dialyse: utilisation de différents tubes à dialyse, utilisation de différentes souches cellulaires ; culture dans un milieu sans sérum ; utilisation d'antiprotéases, « scaling up ». Nous avons étudié la mort cellulaire programmée ou apoptose chez les hybridomes à l'aide de techniques diverses: électrophorèse sur gel, observations morphologiques et suivi du cycle cellulaire. L’apoptose a été induite en utilisant des chocs thermiques, des irradiations gamma, privation de sérum et des inhibiteurs de la synthèse des protéines. Nous avons mis en évidence l'existence d'apoptose spontanée chez la plupart des hybridomes étudiés avec une étude plus approfondie concernant les hybridomes A49 et 12H8. Un hétérohybridome résistant à l'apoptose a été étudié plus en détail (hétérohybridome homme-souris HF2 x 653). Finalement nous avons examiné la toxicité de surfactifs non-ioniques a base de noyau beta-lactame en etudiant respectivement l'apoptose et la necrose sur les hybridomes HF2 x 653 et l'hémolyse sur les globules rouges. Nous avons ensuite débattu des éventuels mécanismes d'action provoquant la mort cellulair

The Neural Correlates of Spatial and Object Working Memory in Elderly and Parkinson’s Disease Subjects

This fMRI study deals with the neural correlates of spatial and objects working memory (SWM and OWM) in elderly subjects (ESs) and idiopathic Parkinson’s disease (IPD). Normal aging and IPD can be associated with a WM decline. In IPD population, some studies reported similar SWM and OWM deficits; others reported a greater SWM than OWM impairment. In the present fMRI research, we investigated whether compensated IPD patients and elderly subjects with comparable performance during the execution of SWM and OWM tasks would present differences in WM-related brain activations. We found that the two groups recruited a prevalent left frontoparietal network when performing the SWM task and a bilateral network during OWM task execution. More specifically, the ESs showed bilateral frontal and subcortical activations in SWM, at difference with the IPD patients who showed a strict left lateralized network, consistent with frontostriatal degeneration in IPD. The overall brain activation in the IPD group was more extended as number of voxels with respect to ESs, suggesting underlying compensatory mechanisms. In conclusion, notwithstanding comparable WM performance, the two groups showed consistencies and differences in the WM activated networks. The latter underline the compensatory processes of normal typical and pathological aging

Synthesis and properties of bioactive surfactants containing β-lactam ring

In this paper we report the synthesis of new molecules containing a β-lactam ring, a hydrophobic and a hydrophilic group. Physico-chemical studies demonstrated the surface activity of these new compounds and the formation of molecular organized systems for some of them. Moreover, aggressiveness of those molecules was evidenced by hemolysis tests and cell cultures. A classification was made to distinguish several groups of β-lactams in accordance with their biocompatibility. A tridimensional relation (structure/physico-chemical properties/biological properties) was therefore found out. The selective and significant antibiotic activity of those β-lactams clearly showed that they were not only surfactants but bio-surfactants.Peer reviewe

Bioactive surfactants containing a β-lactam group: Synthesis and properties

Selective activation of 3-hydroxy-2-hydroxymethyl-2-methyl propanamide with P(NMe2)3-CCl4, and subsequent intramolecular cyclisation yields β-lactam derivatives that have both surface and antibiotic activity.Peer reviewe