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Biomedical subjects

Luc Grandbarbe

Publications and source records attributed to Luc Grandbarbe.

3 recordsLinked to original sources

Tocopherol long chain fatty alcohols decrease the production of TNF-alpha and NO radicals by activated microglial cells.

The synthesis of a series of Tocopherol long chain Fatty Alcohols (TFA) and their biological activities on the modulation of microglial activation are described. Specifically, the 2-(12-hydroxy-dodecyl)-2,5,7,8-tetramethyl-chroman-6-ol, the TFA bearing 12 carbon atoms on the side chain (n=12), shows the most potent inhibition of secretion on nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha) by lipopolysaccharide (LPS)-activated microglia.

Animals↗

Transplantation of neurospheres after granule cell lesions in rats: cognitive improvements despite no long-term immunodetection of grafted cells.

EGF-responsive C17 murine-derived neural stem cells (neurospheres) were grafted into the dentate gyrus of adult male rats after dentate granule cells lesions produced by colchicine injections. Behavioural performance was evaluated over two post-grafting periods, using tests sensitive to hippocampal dysfunctions. The first period began 1 month after grafting and testing conducted in the water maze and the radial maze distinguished working- and reference-memory performance. The second period began 9 months after grafting and learning performance was also evaluated in a Hebb-Williams maze, in addition to both other tests. The lesions induced lasting deficits in all tests. During the first period, the grafts had no effect in either test. Conversely, during the second period, grafted rats showed a weak improvement in the water maze and a significant increase of reference memory performance in the radial maze. In the Hebb-Williams maze, performance of grafted rats was close to normal. Strengthening the idea that dentate gyrus granule cells play an important role in the acquisition of new (perhaps more configural than only spatial) information, our results, moreover, suggest that neurosphere grafts may foster recovery after damage to point-to-point connection systems in the adult brain.

Analysis of Variance↗

Delta-Notch signaling controls the generation of neurons/glia from neural stem cells in a stepwise process.

We examined the role of Notch signaling on the generation of neurons and glia from neural stem cells by using neurospheres that are clonally derived from neural stem cells. Neurospheres prepared from Dll1(lacZ/lacZ) mutant embryos segregate more neurons at the expense of both oligodendrocytes and astrocytes. This mutant phenotype could be rescued when Dll1(lacZ/lacZ) spheres were grown and/or differentiated in the presence of conditioned medium from wild-type neurospheres. Temporal modulation of Notch by soluble forms of ligands indicates that Notch signaling acts in two steps. Initially, it inhibits the neuronal fate while promoting the glial cell fate. In a second step, Notch promotes the differentiation of astrocytes, while inhibiting the differentiation of both neurons and oligodendrocytes.

Animals↗