References of "Leprince, Pierre"
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See detailIn vitro and in vivo modulation of neurotransmitter phenotype in adult DRG neuron.
Schoenen, Jean ULg; Delrée, P.; Martin, Didier ULg et al

Conference (1990)

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See detailCultured neurons release an inhibitor of astroglia proliferation (astrostatine).
Rogister, Bernard ULg; Leprince, Pierre ULg; Bonhomme, Vincent ULg et al

in Journal of Neuroscience Research (1990), 25(1), 58-70

Using in vitro techniques, we looked for a possible downregulation of rat astroglia proliferation by neuronal cells. We demonstrate that medium conditioned by 7-day-old rat cerebellar granule neurons or ... [more ▼]

Using in vitro techniques, we looked for a possible downregulation of rat astroglia proliferation by neuronal cells. We demonstrate that medium conditioned by 7-day-old rat cerebellar granule neurons or by 16-day-old rat embryo hippocampal neurons strongly inhibits the proliferation of cultured astroglial cells. Two neuronal cell lines, the PC12 rat pheocromocytoma and the neuro 2A (N2A) murine neuroblastoma also release such an activity. This release in N2A-conditioned medium (CM) occurs when the cells are at high density and show a low proliferation rate. This activity is present in media conditioned by neuronal cells, but not in media conditioned by normal astrocytes, by two glioma cell lines, or by one fibroblastic cell line. This proliferation inhibitor addresses normal astrocytes: the proliferation of two glioma cell lines, of a fibroblastic cell line, and of the two neuronal cell lines (PC12, N2A) is not inhibited by N2A CM. Moreover, this activity is directed against type 1 astrocytes, but not against type 2. Using three different assays, we demonstrate that DNA synthesis by astroglial cells is inhibited. N2A CM has no cytotoxic effect on astrocytes and does not modify their overall protein synthesis. Using affinity and gel filtration chromatography, we show that this activity is associated with a protein whose molecular weight ranges between 15 and 20 kDa. The possible relationship between this N2A cell-derived astroglia proliferation inhibitor and other types of potential glial proliferation inhibitors has been investigated. A brain glycoprotein immunologically related to epidermal growth factor receptor (EGFR) was reported to inhibit astroglial cell proliferation in vitro. Using polyclonal and monoclonal antibodies against EGFR, we were unable to immunoprecipitate the astrocyte proliferation inhibitor in N2A CM or to demonstrate by immunoblotting the presence of an EGFR-like immunoreactivity in the N2A CM or in the active chromatographic fractions of N2A CM. Transforming growth factor beta (TGF beta) is a well-known modulator of the proliferation of various cell types and was shown to be present in N2A CM. Using a polyclonal anti-TGF beta antibody that recognizes TGF beta on Western blots of N2A CM, we were unable to immunoprecipitate the astrocyte proliferation inhibitor of N2A CM. It seems thus far that the neuronal astroglia proliferation inhibitor is a new protein for which we propose the name astrostatine. [less ▲]

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See detailEnhanced Release of Plasminogen Activator Inhibitor(S) but Not of Plasminogen Activators by Cultured Rat Glial Cells Treated with Interleukin-1
Rogister, Bernard ULg; Leprince, Pierre ULg; Delree, P. et al

in Glia (1990), 3(4), 252-7

Astroglial cells are known to proliferate during development of the nervous system, as well as during post-traumatic gliosis. We have previously shown that the proliferation of cultured astrocytes can be ... [more ▼]

Astroglial cells are known to proliferate during development of the nervous system, as well as during post-traumatic gliosis. We have previously shown that the proliferation of cultured astrocytes can be stimulated by the urokinase-type (uPA) of plasminogen activator (PA) and that astrocytes are able to release such uPA upon stimulation with basic fibroblast growth factor, which is known to act as a mitogen for these cells. Here we report studies on the effects of human interleukin-1 (IL-1) on the release of PA activity by cultured newborn rat astroglial cells. Whereas there is controversy in the literature as to whether IL-1 stimulates multiplication of astroglial cells, we failed to observe such an effect in our system. We did observe, however, a dose-dependent decrease in PA activity in the supernatant of the IL-1 treated cultures. Further analysis revealed that this apparent decrease in PA release was in fact due to an increased release of plasminogen activator inhibitor (PAI). A similar IL-1 induced increase in PAI release was also found to occur in cultures of transformed astrocytes (human glioma LN18) and in cultured Schwann cells, but not in cultures of neurons or neuronal tumour cells. Since protease inhibitors are known to possess neuritogenic properties, our results suggest that IL-1, by its capacity to induce PAI, may promote neuritogenesis. [less ▲]

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See detailCultured Astroglia Release a Neuronotoxic Activity That Is Not Related to the Excitotoxins
Leprince, Pierre ULg; Lefebvre, Philippe ULg; rigo, Jean-Michel et al

in Brain Research (1989), 502(1), 21-7

Neuronal death after brain injury is thought to be in part the result of the activity of the excitotoxins, a family of excitatory amino acids which are released by neurones. We have also described an ... [more ▼]

Neuronal death after brain injury is thought to be in part the result of the activity of the excitotoxins, a family of excitatory amino acids which are released by neurones. We have also described an astroglial cell-derived neuronotoxic activity of low molecular weight whose release can be induced by depolarizing events such as an increase in extracellular potassium concentration. We study here the relationship between this astroglia-derived neuronotoxic activity present in astroglia-conditioned medium (ACM) and the excitotoxins. Using a colorimetric assay of neuronal survival, we show that the ACM neuronotoxic activity, is able to induce the death of all types of neurones tested, including those which are insensitive to excitotoxins. Furthermore, the ACM neuronotoxic activity does not require for its action the extracellular ionic composition which is needed for the activity of excitotoxins. Finally, the ACM neuronotoxic activity is not blocked by competitive or non-competitive antagonists of the various classes of excitotoxin receptors. Those data demonstrate that the astroglia-derived neuronotoxic activity is not related to the excitotoxins. Still, because astrocytes can also be depolarized by members of the excitotoxin family, the possibility exists that the release of astroglia-derived neuronotoxic activity would follow the rise in extracellular excitatory amino acid concentration during nervous system injury. [less ▲]

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See detailIn vitro and in situ experimental modulation of neurotransmitters, phenotypic expression by adult dorsal root ganglion neurons
Schoenen, J.; Delrée, P.; Martin, Didier ULg et al

Conference (1989, November)

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See detailPlasticity and regeneration of spinal cortex after experimental trauma and autograft of dorsal root ganglion neurons
Schoenen, J.; Delrée, P.; Martin, Didier ULg et al

Conference (1989, November)

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See detailIn Vitro Kinetics of a Newborn Rat Astroglia-Derived Neuronotoxic Activity
Leprince, Pierre ULg; rigo, Jean-Michel; Lefebvre, Philippe ULg et al

in Neuroscience Letters (1989), 102(2-3), 268-72

A low-molecular weight astrocyte-derived neuronotoxic activity (ANTA) was detected, using a colorimetric bioassay of cell survival, by its effect on cultured granule cells. This neuronotoxic activity was ... [more ▼]

A low-molecular weight astrocyte-derived neuronotoxic activity (ANTA) was detected, using a colorimetric bioassay of cell survival, by its effect on cultured granule cells. This neuronotoxic activity was found to be released rapidly from newborn rat astrocytes in culture upon incubation in 50 mM K+-containing growth medium. The release by astrocytes could be induced repetitively by successive incubations in high-K+ medium alternating with incubations in normal medium. Astrocytes were also found to inactivate rapidly isobutanol-extracted ANTA in normal K+-containing growth medium. Kinetic studies showed that ANTA induces a slow (greater than 12 h) degeneration of cultured granule cells. ANTA is shown here to be an intermediate of normal astrocyte metabolism and to display appropriate kinetic characteristics compatible with its proposed role in inducing part of the delayed neuronal loss that occurs after a brain injury (secondary neuronal death). [less ▲]

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See detailPurification and Culture of Adult Rat Dorsal Root Ganglia Neurons
Delree, P.; Leprince, Pierre ULg; Schoenen, Jean ULg et al

in Journal of Neuroscience Research (1989), 23(2), 198-206

To study the trophic requirements of adult rat dorsal root ganglia neurons (DRG) in vitro, we developed a purification procedure that yields highly enriched neuronal cultures. Forty to fifty ganglia are ... [more ▼]

To study the trophic requirements of adult rat dorsal root ganglia neurons (DRG) in vitro, we developed a purification procedure that yields highly enriched neuronal cultures. Forty to fifty ganglia are dissected from the spinal column of an adult rat. After enzymatic and mechanical dissociation of the ganglia, myelin debris are eliminated by centrifugation on a Percoll gradient. The resulting cell suspension is layered onto a nylon mesh with a pore size of 10 microns. Most of the neurons, the diameter of which ranged from 17 microns to greater than 100 microns, are retained on the upper surface of the sieve; most of the non-neuronal cells with a caliber of less than 10 microns after trypsinization go through it. Recovery of neurons is achieved by reversing the mesh onto a Petri dish containing culture medium. Neurons to non-neurons ratio is 1 to 10 in the initial cell suspension and 1 to 1 after separation. When these purified neurons are seeded at a density of 3,000 neurons/cm2 in 6 mm polyornithine-laminin (PORN-LAM) coated wells, neuronal survival (assessed by the ability to extend neurites), measured after 48 hr of culture, is very low (from 0 to 16%). Addition of nerve growth factor (NGF) does not improve neuronal survival. However, when neurons are cultured in the presence of medium conditioned (CM) by astrocytes or Schwann cells, 60-80% of the seeded, dye-excluding neurons survive. So, purified adult DRG neurons require for their short-term survival and regeneration in culture, a trophic support that is present in conditioned medium from PNS or CNS glia.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

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See detailNeurotransmitter Phenotype Plasticity in Cultured Dissociated Adult Rat Dorsal Root Ganglia: An Immunocytochemical Study
Schoenen, Jean ULg; Delree, P.; Leprince, Pierre ULg et al

in Journal of Neuroscience Research (1989), 22(4), 473-87

Culturing sympathetic ganglion neurons in vitro may modify phenotypic expression of some neurotransmitters. For dorsal root ganglia (DRG), contradictory results have been reported; most studies have used ... [more ▼]

Culturing sympathetic ganglion neurons in vitro may modify phenotypic expression of some neurotransmitters. For dorsal root ganglia (DRG), contradictory results have been reported; most studies have used immature material. We have therefore performed a detailed immunocytochemical analysis of the transmitter content of cultured adult rat DRG neurons. To demonstrate possible modifications of neurotransmitter phenotypes, we have compared the results obtained with the same techniques on neurons cultured for 3 days and on freshly dissociated DRG cells. Also, the transmitter profile of cultured neurons was compared with that known from in situ studies. Out of 22 antigens studied, 20 were detected in cultured DRG neurons. All of them were expressed in small and/or intermediate-sized cells. Large neurons only contained CGRP, VIP, NPY, beta-END, ENK, and GABA. The percentage of immunostained neurons varied for the various antisera: less than 10% of cultured neurons were positive for ENK, beta-LPH, beta-END, DYN, VASO, and OXY; 10-30% for SOM, CCK, CAT, and SP; and greater than 30% for NPY, CRF, GLU, NT, VIP, GABA, GRP, CGRP, 5-HT, and TRH. In the latter two groups of transmitters (except CGRP), the proportion of immunoreactive neurons was by far larger in cultured than in freshly dissociated DRG. The most pronounced (greater than 25%) increase in the proportion of positively stained neurons after culturing was observed for the GRP, CRF, TRH, and 5-HT antisera. Serotonin was the only transmitter identified in cultured but not in freshly dissociated cells. These data indicate, on one hand, that various antigens, for example, CAT, GABA, NT, TRH, NPY, beta-LPH, and beta-END, which up to now have not been described in DRG in situ, can be detected immunocytochemically a few hours after dissociation of adult rat DRG. On the other hand, several transmitters, for example, VIP, NPY, SP, GABA, GLU, NT, GRP, CRF, TRH, and 5-HT, are expressed in a significantly higher proportion of cells in cultured than in freshly dissociated preparations. This might reflect a change in the phenotypic expression of transmitters due to the new environment generated by the culture conditions, a hypothesis that can be tested by measuring specific mRNA levels. Moreover, considering the plasticity and multipotentiality of their transmitter phenotype, cultured adult DRG neurons might represent an interesting material for autografts into the injured central nervous system. [less ▲]

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See detailParaplégie traumatique. Mise au point et analyse d'un modèle expérimental.
Martin, Didier ULg; Delrée, P.; Leprince, Pierre ULg et al

Conference (1989, March)

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See detailA Colorimetric Assay for the Simultaneous Measurement of Plasminogen Activators and Plasminogen Activator Inhibitors in Serum-Free Conditioned Media from Cultured Cells
Leprince, Pierre ULg; Rogister, Bernard ULg; Moonen, Gustave ULg

in Analytical Biochemistry (1989), 177(2), 341-6

The coupled photometric assay for plasminogen activator reported by Coleman and Green (1981) Methods in Enzymology (Lorand, L., Ed.), Vol. 80, pp. 408-414, Academic Press, San Diego, CA) has been adapted ... [more ▼]

The coupled photometric assay for plasminogen activator reported by Coleman and Green (1981) Methods in Enzymology (Lorand, L., Ed.), Vol. 80, pp. 408-414, Academic Press, San Diego, CA) has been adapted for use with 96-well plates and an automatic microplates spectrophotometer. The assay allows the discrimination between tissue-type and urokinase-type plasminogen activators in cell culture-conditioned media. It provides a level of detection of these enzymes in the range 10(-17) to 10(-13) mol (determined using purified human plasminogen activators), uses no radioisotopes, and is faster and more economical than similar assays using specific peptide substrates for plasminogen activators. Levels of free plasminogen activator inhibitor activity can be simultaneously measured on the same samples by a simple adaptation of the assay. This method allows an easy treatment of the data by interfacing with a computer and should thus be useful when large numbers of samples are assayed. [less ▲]

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See detailInteractions neurotrophiques dans l'oreille interne en développement ?
Lefebvre, Philippe ULg; Weber, Thierry; Rigo, Jean-Michel et al

in Acta Otolaryngologica Belgica (1989), 43(5), 403-409

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See detailDemonstration of neuronotoxic activity in the cerebrospinal fluid of severe head injured patients
Lefebvre, P. P.; Rigo, J. M.; Leprince, Pierre ULg et al

in Agressologie : Revue Internationale de Physio-Biologie et de Pharmacologie Appliquées aux Effets de l'Agression (1988), 29(4), 241-242

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See detailBrain basic fibroblast growth factor stimulates the release of plasminogen activators by newborn rat cultured astroglial cells
Rogister, Bernard ULg; Leprince, Pierre ULg; Pettmann, B. et al

in Neuroscience Letters (1988), 91(3), 321-326

Basic fibroblast growth factor (bFGF), a growth factor for many cell types including newborn rat astroglial cells, stimulates in a dose-dependent fashion the release of plasminogen activators (PAs) by ... [more ▼]

Basic fibroblast growth factor (bFGF), a growth factor for many cell types including newborn rat astroglial cells, stimulates in a dose-dependent fashion the release of plasminogen activators (PAs) by these cells as measured by the fibrin-overlay method or the Coleman and Green's colorimetric assay. This effect of bFGF on PAs secretion (about 4.5-fold increase at 40 ng/ml bFGF) does not result from an aspecific stimulation of protein secretion by astrocytes and is only partly correlated with the mitogenic activity of bFGF. bFGF was also tested on two clonal glioma cell lines (C6 and LN18). Only one of those cell types (LN18) showed a stimulated PA release in the presence of bFGF. These data are discussed with respect to the putative roles of plasminogen activators in the developing nervous system. [less ▲]

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See detailDevelopmental Neurobiology and the physiopathology of brain injury
Moonen, Gustave ULg; Delrée, Paul; Leprince, Pierre ULg et al

in Stein, Don; Sabel, Bernhard (Eds.) Pharmacological approaches to the treatment of brain and spinal cord injury (1988)

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See detailMise en évidence d'une activité neurotoxique dans le liquide céphalo-rachidien de traumatisés crâniens graves
Lefebvre, Philippe ULg; Rigo, Jean-Michel; Leprince, Pierre ULg et al

in Agressologie : Revue Internationale de Physio-Biologie et de Pharmacologie Appliquées aux Effets de l'Agression (1988), 29(4), 241-242

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See detailPlasminogen activators in developing peripheral nervous system, cellular origin and mitogenic effect.
Baron-Van Evercooren, A.; Leprince, Pierre ULg; Rogister, Bernard ULg et al

in Brain Research (1987), 433(1), 101-8

Newborn rat dorsal root ganglia release two different plasminogen activators (PAs): the urokinase (UK) and the tissue (tPA) type. The former is secreted by neurons while the latter is secreted by Schwann ... [more ▼]

Newborn rat dorsal root ganglia release two different plasminogen activators (PAs): the urokinase (UK) and the tissue (tPA) type. The former is secreted by neurons while the latter is secreted by Schwann cells. tPA release by Schwann cells is modulated by choleratoxin, a known mitogen for these cells. UK but not tPA stimulates in a dose-dependent fashion the proliferation of Schwann cells. This effect is observed in the absence of plasminogen, suggesting that the substrate for PAs in the developing nervous system is not plasminogen. Since UK is secreted by neurons, our data suggest a new mechanism for neuronal control of Schwann cell proliferation. [less ▲]

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See detailPlasminogen activators and laminin in developing nervous system
Moonen, Gustave ULg; Leprince, Pierre ULg; Rogister, Bernard ULg

in Metabolism and Development of the Nervous System (1987)

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See detailPlasminogen activators in brain development
Selak, Ivan ULg; Rogister, Bernard ULg; Lefebvre, Philippe ULg et al

in Advances in the Biosciences (1986), 61

Detailed reference viewed: 11 (3 ULg)