References of "Leprince, Pierre"
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See detailModulation of Proteolytic Activity During Neuritogenesis in the Pc12 Nerve Cell: Differential Control of Plasminogen Activator and Plasminogen Activator Inhibitor Activities by Nerve Growth Factor and Dibutyryl-Cyclic Amp
Leprince, Pierre ULg; Rogister, Bernard ULg; Delree, P. et al

in Journal of Neurochemistry (1991), 57(2), 665-74

Extracellular proteolysis is considered to be required during neuritic outgrowth to control the adhesiveness between the growing neurite membrane and extracellular matrix proteins. In this work, PC12 ... [more ▼]

Extracellular proteolysis is considered to be required during neuritic outgrowth to control the adhesiveness between the growing neurite membrane and extracellular matrix proteins. In this work, PC12 nerve cells were used to study the modulation of proteolytic activity during neuronal differentiation. PC12 cells were found to contain and release a 70-75-kDa tissue-type plasminogen activator (tPA) and a much less abundant 48-kDa urokinase-type plasminogen activator. A plasminogen activator inhibitor (PAI) activity with molecular sizes of 54 and 58 kDa was also detected in PC12 cell conditioned medium and formed high-molecular-mass complexes with released tPA. Release of PAI activity was dependent on treatment with nerve growth factor (NGF), whereas tPA synthesis and release were under control of a cyclic AMP-dependent mechanism and increased on treatment with dibutyryl-cyclic AMP [(But)2cAMP] or cholera toxin. Simultaneous treatment with NGF and (But)2cAMP resulted in increases of both tPA and PAI release and enhancement of tPA-PAI complex formation. The resulting plasminogen activator activity in conditioned medium was high in (But)2cAMP-treated cultures with short neuritic outgrowth but remained low in NGF- or NGF plus (But)2cAMP-treated cultures, where neurite extension was, respectively, large and very large. These results suggest that excess proteolytic activity may be detrimental to neuritic outgrowth and that not only PAI release but also tPA-PAI complex formation is associated with production of large and stable neuritic outgrowth. This can be understood as an involvement of PAI in the protection against neurite-destabilizing proteolytic activity. [less ▲]

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See detailKainate and Nmda Toxicity for Cultured Developing and Adult Rat Spiral Ganglion Neurons: Further Evidence for a Glutamatergic Excitatory Neurotransmission at the Inner Hair Cell Synapse
Lefèbvre, Philippe ULg; Weber, T.; Leprince, Pierre ULg et al

in Brain Research (1991), 555(1), 75-83

In the inner ear, the excitatory amino acid glutamate is a proposed neurotransmitter acting at the synapse between hair cells and afferent auditory neurons. Using cultures of 5-day-old rat auditory ... [more ▼]

In the inner ear, the excitatory amino acid glutamate is a proposed neurotransmitter acting at the synapse between hair cells and afferent auditory neurons. Using cultures of 5-day-old rat auditory neurons, we show that the afferent auditory neuronal population can be divided, on the basis of its sensitivity to the neuronotoxic effect of glutamate and its analogs, in at least 3 subpopulations, one responding to N-methyl-D-aspartate (NMDA), one responding to kainate and a third minor one unresponsive to NMDA, kainic acid and glutamate. No toxic effect of quisqualate is observed. The use of specific antagonists (kynurenate and 2-amino-5-phosphonovalerate (DAP-5) demonstrates the specificity of the receptors to the excitatory amino acids on the afferent auditory neurons. Afferent auditory neurons from adult rats can also be cultured and in these preparations only the large neurons are sensitive to glutamate, kainate and NMDA while the small neurons are not responsive, suggesting that a glutamatergic neurotransmission occurs only at this synapse between the inner hair cells and the large radial afferent auditory neurons. We also show that, in vitro, the organ of Corti releases, in response to an increased potassium concentration and in the presence of calcium, a toxic activity for the afferent auditory neurons that is antagonized by kynurenate and DAP-5. Pathophysiological implications are discussed. [less ▲]

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See detailGrafts of Syngenic Cultured, Adult Dorsal Root Ganglion-Derived Schwann Cells to the Injured Spinal Cord of Adult Rats: Preliminary Morphological Studies
Martin, Didier ULg; Schoenen, Jean ULg; Delree, P. et al

in Neuroscience Letters (1991), 124(1), 44-8

Highly enriched cultures of Schwann cells were obtained from adult rat dorsal root ganglia and implanted (5 x 10(5) -9 x 10(5) cells) in the spinal cord of syngenic adult rats at the site of an acute ... [more ▼]

Highly enriched cultures of Schwann cells were obtained from adult rat dorsal root ganglia and implanted (5 x 10(5) -9 x 10(5) cells) in the spinal cord of syngenic adult rats at the site of an acute compression lesion produced by a subdural inflatable microballoon. These autografts survived and invaded the host tissue, reducing central cavitation and astrocytic gliosis. They dramatically promoted ingrowth of axons, the majority of which appeared to come from the dorsal roots as judged by their neuropeptide content. Invasion of the transplants by descending, e.g. aminergic fibers, was negligible at survival times of up to 4 months. Nonetheless, autologous Schwann cells, which are readily available in the host, represent a promising material for grafts into the injured spinal cord. [less ▲]

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See detailProtéases et inhibiteurs de protéases : implications multiples dans le développement et le vieillissement cérébral
Leprince, Pierre ULg; Rogister, Bernard ULg; Delrée, Paul et al

in Revue d'Oto-Neuro-Ophtalmologie (1991), 12(13), 30-38

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See detailNeuronotrophic factors involvement in the regeneration of adult afferent auditory neurons.
Lefebvre, P.; Weber, T.; Delrée, P. et al

Conference (1990, November 10)

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See detailEffets de facteurs neuronotrophiques sur la régénération des neurones auditifs adultes in vitro
Lefebvre, Philippe ULg; Weber, T.; Delrée, P. et al

Conference (1990, November)

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See detailPotassium-Induced Release of an Endogenous Toxic Activity for Outer Hair Cells and Auditory Neurons in the Cochlea: A New Pathophysiological Mechanism in Meniere's Disease?
Lefebvre, Philippe ULg; Weber, T.; Rigo, Jean-Michel et al

in Hearing Research (1990), 47(1-2), 83-93

In Meniere's disease, the increase of extracellular potassium concentration in the perilymph is thought to play a key role in determining the progressive loss of cochlear hair cells. In this paper, we ... [more ▼]

In Meniere's disease, the increase of extracellular potassium concentration in the perilymph is thought to play a key role in determining the progressive loss of cochlear hair cells. In this paper, we describe a serum-free culture preparation of hair cells from 5 day-old rat and report the release by the cochlea, in response to an increase of extracellular potassium concentration, of a cytotoxic activity active on hair cells and auditory neurons. The toxic activity is associated with low molecular weight (less than 10,000 Dalton) molecule(s) as revealed by ultrafiltration. Morphological studies performed on the organ of Corti incubated during 24 h in the presence of the cochlea-derived toxic activity (CTA), show that this factor is toxic for hair cells and not for supporting or surrounding cells. The release of CTA occurs both in the spiral ganglion and in the organ of Corti. We suggest that this cochlea-derived toxic activity may play an important role in the pathophysiology of the hearing loss that occurs during the progression of Meniere's disease. [less ▲]

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See detailExperimental modulation of neurotransmitter phenotype in adult dorsal root ganglion neurons.
Schoenen, Jean ULg; Delrée, P.; Jammaer, R. et al

Conference (1990, June 30)

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See detailIn vitro and in vivo modulation of neurotransmitter phenotype in adult dorsal root ganglion neurons.
Schoenen, Jean ULg; Delrée, P.; Jammaer, R. et al

Conference (1990, June 16)

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See detailAutografts of cultured Schwann cell in the injured spinal cord.
Schoenen, Jean ULg; Martin, Didier ULg; Delrée, P. et al

Conference (1990, May 19)

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See detailNeuronotrophic Effect of Developing Otic Vesicle on Cochleo-Vestibular Neurons: Evidence for Nerve Growth Factor Involvement
Lefebvre, Philippe ULg; Leprince, Pierre ULg; Weber, T. et al

in Brain Research (1990), 507(2), 254-60

In the developing inner ear, the existence of a neuronal death and of a peripheral target-derived trophic effect on cochleovestibular neurons has been documented. Using cultures of rat cochleovestibular ... [more ▼]

In the developing inner ear, the existence of a neuronal death and of a peripheral target-derived trophic effect on cochleovestibular neurons has been documented. Using cultures of rat cochleovestibular neurons, we show that the E12 otic vesicle releases a factor promoting the survival and the neuritogenesis of these neurons, and that this effect is mimicked by NGF. The effect of the optic vesicle conditioned medium (OVCM) on cochleovestibular neurons is suppressed by anti-NGF antibodies. OVCM is neuronotrophic for NGF-sensitive sympathetic neurons, an effect that is also suppressed by anti-NGF antibodies, further demonstrating the presence of biologically active nerve growth factor. [less ▲]

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See detailMultiple roles for plasminogen activator system in nervous system development
Leprince, Pierre ULg; Rogister, Bernard ULg; Delrée, Paul et al

in Serine proteases and their serpin inhibitors in the Nervous System (1990)

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