References of "Leprince, Pierre"
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See detailNeuronal Control of Astrocytes Proliferation
Rogister, Bernard ULg; Leprince, Pierre ULg; Martin, Didier ULg et al

in Fedoroff, S.; Juurlink, B. H. J.; Doucette, R. (Eds.) Biology and pathology of astrocyte-neuron interactions (1993)

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See detailSyngeneic Grafting of Adult Rat Drg-Derived Schwann Cells to the Injured Spinal Cord
Martin, Didier ULg; Schoenen, Jean ULg; Delree, P. et al

in Brain Research Bulletin (1993), 30(3-4), 507-14

A subdural inflatable micro-balloon was used to induce closed traumatic contusion to adult rat spinal cord. This spinal cord injury model was associated with reproducible and graded neurological deficits ... [more ▼]

A subdural inflatable micro-balloon was used to induce closed traumatic contusion to adult rat spinal cord. This spinal cord injury model was associated with reproducible and graded neurological deficits and histopathological alterations. At various delays after injury, transplantations of syngeneic adult cultured dorsal root ganglion-derived Schwann cells were performed into the spinal cord lesion. The transplants were well integrated and reduced the microcystic posttraumatic cavitation as well as the gliosis. Schwann cells transplants were invaded by numerous regenerating neurites most of which, based upon their neurotransmitter contents, seem to originate from the dorsal root ganglion. [less ▲]

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See detailIn Vitro and in Vivo Modulation of 5-Hydroxytryptamine-, Thyrotropin-Releasing Hormone- and Calcitonin-Gene Related Peptide-Like Immunoreactivities in Adult Rat Sensory Neurons
Delree, P.; Martin, Didier ULg; Sadzot-Delvaux, Catherine ULg et al

in Neuroscience (1992), 51(2), 401-10

In a previous work we have shown that culturing adult rat dorsal root ganglia neurons modifies their neurotransmitter phenotype in such a way that cultured neurons synthesize transmitters that are not ... [more ▼]

In a previous work we have shown that culturing adult rat dorsal root ganglia neurons modifies their neurotransmitter phenotype in such a way that cultured neurons synthesize transmitters that are not found in situ, while several other transmitters are expressed in a much higher percentage of neurons in culture than in situ [Schoenen J. et al. (1989) J. Neurosci. Res. 22, 473-487]. The aim of the present study was to investigate the origin and the nature of the relevant environmental signals that allow this plasticity to be expressed, focusing on three neurotransmitters: 5-hydroxytryptamine, thyrotropin-releasing hormone and calcitonin-gene related peptide. The main results can be summarized as follows: (1) culturing cells in fetal calf serum or on feeder layers of astrocytes, Schwann cells or fibroblasts partially inhibits the serotoninergic phenotype of dorsal root ganglia neurons; (2) in vivo disconnection of dorsal root ganglia from their spinal targets but not from their peripheral or supraspinal targets induces a significant increase of the percentage of 5-hydroxytryptamine- and thyrotropin-releasing hormone-positive neurons in disconnected ganglia; (3) growth factors such as ciliary neuronotrophic factor or basic fibroblast growth factor but not nerve growth factor repress 5-hydroxytryptamine and calcitonin gene-related peptide immunoreactivity in cultured sensory neurons. In conclusion, neurotransmitter gene expression of adult dorsal root ganglia neurons is controlled by complex influences. Our data suggest that thyrotropin-releasing hormone and 5-hydroxytryptamine gene expression are tonically repressed in vivo by factors originating from the spinal segmental level and that growth factors such as ciliary neurotrophic factor or basic fibroblast growth factor could be potential vectors of this repressing effect. [less ▲]

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See detailExperimental Acute Traumatic Injury of the Adult Rat Spinal Cord by a Subdural Inflatable Balloon: Methodology, Behavioral Analysis, and Histopathology
Martin, Didier ULg; Schoenen, Jean ULg; Delree, P. et al

in Journal of Neuroscience Research (1992), 32(4), 539-50

We describe an experimental model to produce closed traumatic injuries to the spinal cord of adult rats. This model uses an inflatable balloon that is introduced in the dorsal subdural space and moved to ... [more ▼]

We describe an experimental model to produce closed traumatic injuries to the spinal cord of adult rats. This model uses an inflatable balloon that is introduced in the dorsal subdural space and moved to a location rostral to the laminectomy site. The spinal cord trauma can be graded by varying either the duration of compression or the volume of saline used to inflate the balloon. The locomotor deficit of animals with various degrees of injury has been assessed at increasing delays after trauma. The parameters generating transient or definitive deficits of varying intensity were defined. Some injured animals underwent nuclear magnetic resonance imaging. Detailed histopathological studies demonstrated that the extent of the spinal lesion was significantly correlated with the physical parameters of compression and with the severity of the behavioral deficit. [less ▲]

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See detailMécanismes de communication cellulaire dans le système nerveux périphérique en régénération
Leprince, Pierre ULg; Delree, P.; Rogister, Bernard ULg et al

in Revue Médicale de Liège (1992), 47(3), 115-8

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See detailThree-dimensional organ culture systems
Rogister, Bernard ULg; Rigo, Jean-Michel; Lefebvre, Philippe ULg et al

in Boulton, Alan; Baker, Glen; Walz, Wolfgang (Eds.) Practical Cell Culture Techniques (1992)

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See detailPlasticité des neurones sensoriels primaires chez le rat adulte. Etude in vitro et in vivo.
Moonen, Gustave ULg; Delrée, P.; Martin, Didier ULg et al

Conference (1991, November 16)

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See detailIn vitro and in vivo modulation of transmitter phenotype in adult rat DRG neurons.
Moonen, Gustave ULg; Schoenen, Jean ULg; Delrée, P. et al

Conference (1991, August 11)

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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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