References of "Moonen, Gustave"
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See detailCytokine Production by Human Thymic Epithelial Cells: Control by the Immune Recognition of the Neurohypophysial Self-Antigen
Martens, Henri ULg; Malgrange, Brigitte ULg; Robert, F. et al

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 ▲]

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See detailProtein Kinase- and Staurosporine-Dependent Induction of Neurite Outgrowth and Plasminogen Activator Activity in Pc12 Cells
Leprince, Pierre ULg; Bonvoisin, Catherine ULg; Rogister, Bernard ULg et al

in Biochemical Pharmacology (1996), 52(9), 1399-405

We analysed how interactions between protein kinase-dependent intracellular signalling pathways were implicated in the control of the production of tissue-type plasminogen activator (tPA) and the ... [more ▼]

We analysed how interactions between protein kinase-dependent intracellular signalling pathways were implicated in the control of the production of tissue-type plasminogen activator (tPA) and the generation of neurite outgrowth by PC12 cells. To that aim, cells were treated with agents that interact with the trk receptor and with protein kinases A and C. Nerve growth factor induced only the formation of large neurites. The release of the protease and the production of short neurite outgrowth were found to be protein-kinase-A-dependent events that could be enhanced by simultaneous activation of protein kinase C with phorbol ester. At high concentration, staurosporine, a nonselective inhibitor of protein kinases, induced the production of short neurites and mimicked the protein-kinase-A-dependent effect on tPA release. Such a response was not observed with K-252a, an analogue of staurosporine devoid of neurite-outgrowth-promoting activity. The responses to protein kinase A stimulation and the addition of staurosporine, although similar, seemed to occur through an activation of distinct, yet interacting, signalling pathways. In conclusion, tPA release and large neurite outgrowth from PC12 cells are controlled by parallel, albeit interacting, pathways, suggesting that these two potentially antagonistic events in PC12 cell differentiation can be modulated in a concerted way or independently of each other, depending on the activity of several protein kinases. [less ▲]

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See detailNt-3 Has a Tropic Effect on Process Outgrowth by Postnatal Auditory Neurones in Vitro
Malgrange, Brigitte ULg; Lefebvre, P. P.; Martin, Didier ULg et al

in Neuroreport (1996), 7(15-17), 2495-9

CONFOCAL analysis of early postnatal auditory neurones in a bicompartmental culture system was used to test for chemoattractant properties of NGF, BDNF and NT-3 on neuronal process outgrowth. NT-3 exerted ... [more ▼]

CONFOCAL analysis of early postnatal auditory neurones in a bicompartmental culture system was used to test for chemoattractant properties of NGF, BDNF and NT-3 on neuronal process outgrowth. NT-3 exerted a strong tropic effect on neuritic outgrowth from auditory neurones in this system. BDNF and NGF did not have any tropic activity that directed processes outgrowth from auditory neurones. However, BDNF was important for the support of neuronal survival in NGF-treated cultures and for neuritogenesis in NT-3-treated cultures. Since NT-3 has been identified as both a survival factor and a chemotropic agent for auditory neurones, it is likely that this neurotrophin will be a useful therapeutic agent in the treatment of damaged cochleae for the recovery of hearing. [less ▲]

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See detailEffects of Schwann Cell Transplantation in a Contusion Model of Rat Spinal Cord Injury
Martin, Didier ULg; Robe, Pierre ULg; Franzen, Rachelle ULg et al

in Journal of Neuroscience Research (1996), 45(5), 588-597

Cultured Schwann cells were transplanted at various delays into a spinal cord contusion injury performed at low thoracic level in adult female rats. The Schwann cells were purified from the dorsal root ... [more ▼]

Cultured Schwann cells were transplanted at various delays into a spinal cord contusion injury performed at low thoracic level in adult female rats. The Schwann cells were purified from the dorsal root ganglia of adult syngeneic animals. the transplants were well tolerated, and the transplanted Schwann cells invaded the injured spinal cord. As quantified using video image analysis, the survival and growth of the transplanted cells were poor when the grafting procedure was performed 3-4 days after injury and very good when performed immediately or 10 days after injury, in which cases post-traumatic micro- and macrocavitation were strongly reduced. In animals grafted immediately after injury but not in animals grafted after 10 days, post-traumatic astrogliosis was much reduced. The Schwann cells transplanted area was invaded by numerous regenerating axons, the vast majority of which were, based on the neurotransmitter (CGRP and SP) profile, originating from dorsal root ganglion. No regeneration of the corticospinal tract as assessed after anterograde tracing or of descending aminergic fibers could be demonstrated. [less ▲]

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See detailNeurotrophic Factors: Past and Future
Moonen, Gustave ULg; Malgrange, Brigitte ULg; Rigo, Jean Michel et al

in Acta Neurologica Belgica (1996), 96(3), 203-18

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See detailPorous biomaterials tailored for cell culture.
Grandfils, Christian ULg; Maquet, V; Ropson, N et al

in Cytotechnology (1996), 21

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See detailIn vitro expression of RC2-labeled antigens as radial glial cells markers in cultures derived from mouse embryonic brain
Leprince, P; Chanas-Sacré, G; Lewin, M et al

Poster (1996)

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See detailIdentification of antigens recognized in the developing mouse brain by the RC2 antibody, a marker of radial glia
Leprince, Pierre ULg; Chanas-Sacre, G.; Wattiez, R. et al

in International Journal of Developmental Neuroscience (1996), 14(Sup. 1), 84

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See detailSurface modification of biomaterials in order to control cell adhesion.
Grandfils, C.; Maquet, V.; Jérôme, R. et al

Conference (1996)

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See detailAlpha-MSH stimulates neurite outgrowth of neonatal rat corticospinal neurons in vitro.
Joosten, E. A.; Verhaagh, S.; Martin, Didier ULg et al

in Brain Research (1996), 736(1-2), 91-8

Peptides related to melanocortin (alpha MSH) and corticotropin (ACTH), collectively termed melanocortins, exert trophic effects on the outgrowth of neurites from peripheral and central nervous system in ... [more ▼]

Peptides related to melanocortin (alpha MSH) and corticotropin (ACTH), collectively termed melanocortins, exert trophic effects on the outgrowth of neurites from peripheral and central nervous system in vitro. Here we study the neurite outgrowth promoting effect of alpha-MSH on corticospinal (CS) neurons in vitro. Corticospinal neurons were identified in cell culture of neonatal rat cortex by immunostaining of cholera toxin subunit B (CTB), retrogradely transported from the cervical parts of the spinal cord. The CTB-immunoreactive neurons represent a small percentage (3-5%) of the total cell population after 72 h in vitro. The axons or dendrites of cortical and CTB-labelled layer V neurons were visualized using antibodies against axon- or dendrite-specific markers and measured using a semi-automatic quantification device. Here we report that alpha-MSH stimulates axonal as well as dendrite outgrowth from both total and CTB-labelled neurons with a bell-shape response curve. Axonal outgrowth of CTB-labelled neurons was dose-dependently stimulated with a maximal effect of 50% at 10(-10) M alpha-MSH. The maximal effect for stimulation of axon outgrowth for the total cortex population was observed at 10(-8) M alpha-MSH. In addition dendrite outgrowth of both total and CTB-labelled neurons is stimulated in a dose-dependent manner with maximal effects (varying between 46 and 48%) at 10(-8) M alpha-MSH. Explanations in the shift for the optimal alpha-MSH concentration for stimulation of axonal outgrowth of CTB-labelled layer V neurons as compared to total cortex neurons are discussed. [less ▲]

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See detailAstroglia-released factor with negative allosteric modulatory properties at the GABA A receptor.
Rigo, Jean-Michel; Belachew, Shibeshih ULg; Coucke, Paul et al

in Biochemical Pharmacology (1996), 52(3), 465-473

We have previously shown, using whole-cell patch-clamp techniques, that astrocytes release a negative allosteric modulator of the gamma-aminobutyric acid type A receptor (GABAA receptor) with beta ... [more ▼]

We have previously shown, using whole-cell patch-clamp techniques, that astrocytes release a negative allosteric modulator of the gamma-aminobutyric acid type A receptor (GABAA receptor) with beta-carboline-like properties, thus, likely to act at the benzodiazepine site. Here, using patch-clamp and binding techniques, we confirm that the low-molecular-weight fraction of astroglia-conditioned medium (ACM lmf) contains a factor(s) that negatively modulates GABAA-receptor function. This factor, like beta-carbolines, enhances the specific binding of [35S]t-butyl bicyclophosphorothionate (TBPS) to adult rat cortical membranes in the presence of GABA. However, it fails to interact with various ligands of the benzodiazepine (BZD) site of the GABAA receptor ([3H]flunitrazepam, [3H]Ro 15-1788 and [3H]Ro 15-4513). The question of the actual binding site of the astroglia-derived factor on the GABAA receptor, thus, remains open and can be addressed only after the purification of the active molecule(s) of ACM Imf has been completed, and a labeled form of the endogenous ligand becomes available. Taken together, however, the data suggest that type 1 astrocytes are able to modulate the effects of the main inhibitory neurotransmission in the central nervous system. [less ▲]

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See detailPreparation of a Macroporous Biodegradable Polylactide Implant for Neuronal Transplantation
Schugens, C.; Grandfils, Christian ULg; Jérôme, Robert ULg et al

in Journal of Biomedical Materials Research (1995), 29(11), 1349-62

This article reports the production of a surgical implant meeting several specific requirements such as biocompatibility, biodegradability, macroporosity, and flexibility. Porosity was controlled by an ... [more ▼]

This article reports the production of a surgical implant meeting several specific requirements such as biocompatibility, biodegradability, macroporosity, and flexibility. Porosity was controlled by an original method consisting of the aggregation of calibrated poly-D,L-lactide microparticles. The size of the interstices between the aggregated microspheres was in a direct relationship to the microsphere diameter. A first approach was based on coating the microspheres with poly(vinyl alcohol) followed by chemically crosslinking the coating layers that were in mutual contact. This method was disregarded because of the acute cytotoxicity of glutaraldehyde used as the crosslinking agent, the absence of macroporosity, and the complete lack of flexibility. A physical technique of aggregation was then tested, which relied on the plasticization of poly-D,L-lactide microspheres with triethylcitrate to the point where microspheres strongly adhered to each other when they were in contact. This method has proved to be straightforward and definitely superior to the chemical approach, particularly with respect to cytotoxicity, control of macroporosity, and flexibility. A polymer support was thus successfully which was biodegradable, macroporous( interconnected pores of 10-100 microns in diameter), and flexible. This potential medical device is presently being used for neuronal transplantation in the central nervous system. [less ▲]

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See detailA model of spinal cord injury: the balloon-compressive model
Martin, Didier ULg; Franzen, R.; Robe, Pierre ULg et al

Conference (1995, September 03)

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See detailPorous biomaterials tailored for cell culture
Grandfils, Christian ULg; Maquet, V; Ropson, N et al

Conference (1995, May 29)

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See detailAstroglia-Released Factor Shows Similar Effects as Benzodiazepine Inverse Agonists
Rigo, Jean-Michel; Belachew, Shibeshih ULg; Lefebvre, P. P. et al

in Journal of Neuroscience Research (1994), 39(4), 364-76

Media conditioned by cultured neonatal cerebral cortex microexplants (CCM) or astrocytes (ACM) contain low molecular weight (< 1,000 Da) substance(s) which inhibits the gamma aminobutyric acid (GABA ... [more ▼]

Media conditioned by cultured neonatal cerebral cortex microexplants (CCM) or astrocytes (ACM) contain low molecular weight (< 1,000 Da) substance(s) which inhibits the gamma aminobutyric acid (GABA)-induced inward current recorded in cerebellar granule cells and hippocampal neurons in culture using the whole-cell patch-clamp technique. This effect is specific for CCM and ACM, as medium conditioned by PC12 cells (PC12CM) does not affect the GABA response of these cells. It is also specific for GABA-induced currents because glutamate-induced currents do not change either in amplitude or in shape in the presence of CCM or ACM. The inhibitory effect on the GABA response in cerebellar granule cells of both ACM and CCM could be suppressed by flumazenil, a specific benzodiazepine (BZD) antagonist and could be mimicked by two BZD inverse agonists. These data thus demonstrate the presence of a BZD inverse agonist-like activity in CCM and ACM. This effect of ACM on different neuronal cell types was heterogenous since no detectable effect could be observed on the GABA-induced current in GABA-responsive dorsal root ganglion (DRG) neurons, presumably reflecting a functional heterogeneity of the GABAA receptors present in these different neuronal subsets. By the release of such an endogenous BZD inverse agonist-like activity, glia cells could possibly modulate GABAA receptor-mediated responses. [less ▲]

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