Beta-Carbolines Induce Apoptotic Death of Cerebellar Granule Neurones in Culture

in Neuroreport (1996), 7(18), 3041-5

Apart from its role in fast inhibitory transmission, only neurotrophic effects have been reported following activation of the GABAA receptor. Here, we show that n-butyl-beta-carboline-3-carboxylate and n ... [more ▼]

Apart from its role in fast inhibitory transmission, only neurotrophic effects have been reported following activation of the GABAA receptor. Here, we show that n-butyl-beta-carboline-3-carboxylate and n-methyl-beta-carboline-3-carboxamide, which are negative allosteric modulators of the GABAA receptor acting at the benzodiazepine site, are neurotoxic for cerebellar granule neurones in culture. The beta-carboline-induced neuronal death is apoptotic since DNA internucleosomal fragmentation was induced and the neurotoxicity could be prevented by inhibitors of mRNA or protein synthesis. As GABA and benzodiazepine ligands (diazepam and Ro 15-1788) protect cerebellar granule cells against beta-carboline-induced toxicity, these data raise the possibility that the interaction between the beta-carbolines and the GABAA receptor is the triggering event leading to neuronal apoptosis. [less ▲]

Growth of Cayley and diluted Cayley trees with two kinds of entities

in Journal of Physics : A Mathematical & General (1996), 29(22), 7089-7104

A kinetic growth model derived from the magnetic Eden model is introduced in order to simulate the growth of hierarchical structures, such as Cayley trees. We only consider the case where two kinds of ... [more ▼]

A kinetic growth model derived from the magnetic Eden model is introduced in order to simulate the growth of hierarchical structures, such as Cayley trees. We only consider the case where two kinds of entities are competing with each other can be further subjected to an external field. The very relevant case in which both kinds of entities have different coordination numbers is introduced here for the first time, and is called the diluted Cayley tree. Physical and geometrical properties of the finite and infinite trees are exactly found and simulated. Finite-size effects are emphasized and illustrated on the global or local magnetization and on the chemical activity. Asymptotic limits are given in each case. The generated patterns can be related to a correlated percolation problem briefly discussed in the appendix. [less ▲]

Current concepts in the prevention, diagnosis and treatment of the cervical whiplash syndrome : Acute cervical central cord syndrome.

Conference (1996, November 15)

Cytokine Production by Human Thymic Epithelial Cells: Control by the Immune Recognition of the Neurohypophysial Self-Antigen

in Regulatory Peptides (1996), 67(1), 39-45

Oxytocin (OT) has been shown to be the dominant peptide of the neurohypophysial family expressed by thymic epithelial and nurse cells (TEC/TNC) in various species. Thymic OT is not secreted but, after ... [more ▼]

Oxytocin (OT) has been shown to be the dominant peptide of the neurohypophysial family expressed by thymic epithelial and nurse cells (TEC/TNC) in various species. Thymic OT is not secreted but, after translocation of a hybrid neurophysin/MHC class I protein, is integrated within the plasma membrane of TEC, thus allowing its presentation to pre-T cells. In order to further demonstrate that thymic OT behaves like a membrane antigen, we assessed the effect of mAbs to OT on cytokine productions by cultures enriched in human TEC. 75-85% pure TEC cultures were prepared from human thymic fragments. Using immunofluorescence and confocal microscopy, ir-OT, ir-interleukin-1 beta (IL-1 beta), ir-interleukin-6 (IL-6) and ir-leukemia inhibitory factor (LIF) could be detected in these TEC cultures. ir-OT was restricted to TEC, while some ir-IL-6 and ir-LIF were also seen in occasional fibroblasts. In basal conditions, ir-IL-6 and ir-LIF (but not ir-OT and ir-IL-1 beta) were detected in the supernatants of human TEC cultures. MAbs to OT induced a marked increase of ir-IL-6 and ir-LIF secretion in TEC cultures. No significant effect was observed using mAbs against vasopressin, mouse immunoglobulins, or control ascitic fluid controls. These data show that OT is fully processed and recognized by specific mAbs at the outer surface of TEC plasma membrane. They further support that thymic OT behaves as the self-antigen of the neurohypophysial family. [less ▲]

Président de la session “Heroic Fantasy”

Diverse speeche and writing (1996)

Evidence of involvement of yeast proliferating cell nuclear antigen in DNA mismatch repair

in Journal of Biological Chemistry (1996), 271(45), 27897-90

Odeurs de stations d'épuration : principaux composés odorants et lutte contre les odeurs

Conference (1996, November 07)

Synthesis and properties of poly[isobornyl methacrylate (IBMA)-b-butadiene (BD)-b-IBMA] copolymers : new thermoplastic elastomers of a large service temperature range

in Macromolecules (1996), 29(16), 7316-7332

Anionic polymerization of isobornyl methacrylate (IBMA) has been studied in THF and toluene in a temperature range from −78 to +40 °C by using (1,1-diphenyl-3,3-dimethylbutyl)lithium (DDBLi) as an ... [more ▼]

Anionic polymerization of isobornyl methacrylate (IBMA) has been studied in THF and toluene in a temperature range from −78 to +40 °C by using (1,1-diphenyl-3,3-dimethylbutyl)lithium (DDBLi) as an initiator in the presence of LiCl or not. Effect of solvent and polymerization temperature on tacticity has been studied. The reactivity of IBMA is comparable to tert-butyl methacrylate (tBMA), and polymers of a very narrow molecular weight distribution (<1.10) have been synthesized at room temperature, in THF, in the presence of LiCl. The Tg of PIBMA is found to vary from 170 to 206 °C with chain tacticity. Poly(isobornyl methacrylate) (PIBMA)−polybutadiene (PBD)−PIBMA triblock copolymers have been synthesized by using the m-diisopropenylbenzene (m-DIB)/tert-butyllithium (t-BuLi) diadduct as an initiator. The PBD midblock has been prepared in a cyclohexane/diethyl ether (100/6, v/v) mixture at room temperature. THF has been added [cyclohexane/diethyl ether/THF (100/6/100, v/v/v)] before the IBMA polymerization takes place at either −78 or +25 °C. Triblock copolymers of a very narrow molecular weight distribution (1.10) have been synthesized even at 25 °C, and no gel formation has been observed. These new triblock copolymers exhibit high tensile strength (30 MPa), high ultimate elongation (1000%), and high upper service temperature (160 °C). [less ▲]

A method to optimize intermediate-passband photometric systems.

in Astronomy and Astrophysics. Supplement Series (1996), 119

A method is proposed to optimize the definition of existing photometric filters in order to minimize passband-matching problems. It is argued that the "improved" systems should generally yield better ... [more ▼]

A method is proposed to optimize the definition of existing photometric filters in order to minimize passband-matching problems. It is argued that the "improved" systems should generally yield better astrophysical parameters than the original ones. Although of a general scope, the method is checked on intermediate-passband filters of the Stroemgren system. [less ▲]

A toy model for life at the "edge of chaos"

in Computers & Graphics (1996), 20(6), 921-923

In this short paper, we illustrate the emergence of complex structures from a simple model of life at the "edge of chaos". The visualization of the generated patterns provides a good way for understanding ... [more ▼]

In this short paper, we illustrate the emergence of complex structures from a simple model of life at the "edge of chaos". The visualization of the generated patterns provides a good way for understanding the self-organized critical dynamics of the model. [less ▲]