References of "Nollevaux, Geraldine"
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See detailRapport scientifique et technique final du projet HYDRASANTE
Boudry, Christelle ULg; François, Emmanuelle ULg; Nollevaux, Géraldine et al

Report (2013)

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See detailRapport scientifique et technique du projet HYDRASANTE (annee 3)
Boudry, Christelle ULg; François, Emmanuelle ULg; Nollevaux, Géraldine et al

Report (2013)

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See detailDevelopment of a serum-free co-culture of human intestinal epithelium cell-lines (Caco-2/HT29-5M21)
Nollevaux, Géraldine; Deville, Christelle ULg; Elmoualij, Benaïssa ULg et al

in BMC Cell Biology (2006), 7

Background: The absorptive and goblet cells are the main cellular types encountered in the intestine epithelium. The cell lineage Caco-2 is a model commonly used to reproduce the features of the bowel ... [more ▼]

Background: The absorptive and goblet cells are the main cellular types encountered in the intestine epithelium. The cell lineage Caco-2 is a model commonly used to reproduce the features of the bowel epithelium. However, there is a strong debate regarding the value of Caco-2 cell culture to mimick in vivo situation. Indeed, some authors report in Caco-2 a low paracellular permeability and an ease of access of highly diffusible small molecules to the microvilli, due to an almost complete lack of mucus. The HT29-5M21 intestinal cell lineage is a mucin-secreting cellular population. A co-culture system carried out in a serum-free medium and comprising both Caco-2 and HT29-5M21 cells was developed. The systematic use of a co-culture system requires the characterization of the monolayer under a given experimental procedure. Results: In this study, we investigated the activity and localization of the alkaline phosphatase and the expression of IAP and MUC5AC genes to determine a correlation between these markers and the cellular composition of a differentiated monolayer obtained from a mixture of Caco-2 and HT29-5M21 cells. We observed that the culture conditions used ( serum-free medium) did not change the phenotype of each cell type, and produced a reproducible model. The alkaline phosphatase expression characterizing Caco-2 cells was influenced by the presence of HT29-5M21 cells. Conclusion: The culture formed by 75% Caco-2 and 25% HT29-5M21 produce a monolayer containing the two main cell types of human intestinal epithelium and characterized by a reduced permeability to macromolecules. [less ▲]

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See detailIn vitro transport studies of nifedipine nanoparticles across Caco-2/HT29- 5M21 cultures and co-cultures
Hecq, Julien; Nollevaux, Géraldine; Deleers, M. et al

Poster (2006)

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See detailNifedipine nanocrystals: pharmacokinetic evaluation in the rat and permeability studies in Caco-2/HT29-5M21 (co)-cultures
Hecq, Julien; Nollevaux, Géraldine; Deleers, M. et al

in Journal of Drug Delivery Science and Technology (2006), 16(6, NOV-DEC), 437-442

Poorly water-soluble drugs such as nifedipine (NIF) (similar to 20 mu g/mL) offer challenging problems in drug formulation as poor solubility is generally associated with poor dissolution characteristics ... [more ▼]

Poorly water-soluble drugs such as nifedipine (NIF) (similar to 20 mu g/mL) offer challenging problems in drug formulation as poor solubility is generally associated with poor dissolution characteristics and thus with poor oral bioavailability (BCS class H drugs). In order to enhance these characteristics, formulation of NIF as nanocrystals was carried out. NIF nanoparticles (NP) were prepared using high-pressure homogenization (HPH). Solubility and dissolution characteristics have been reported in previous work to be significantly enhanced for NIF NP. Influence of NIF particle size on NIF permeation rate across intestinal cell models (Caco-2 and HT29-5M21 cultures and co-cultures) was investigated in order to complement these promising in vitro data. Apical to basolateral transfer studies were carried out across Caco-2 and HT29-5M21 cultures and co-cultures. Caco-2/HT29-5M21 co-cultures (seeding ratio 3: 1) were evaluated to better represent in vivo intestinal conditions. The influence of chitosan in the NIF NP formulation with regard to in vitro NIF permeation rate was also evaluated. These studies showed that NIF permeation rate across the different in vitro models evaluated can be significantly enhanced (approximate to 6-fold) by formulation of NIF as nanoparticles. No significant difference was observed either in the presence of chitosan in the formulation or between the three cell models evaluated. To complement these observations, preliminary in vivo pharmacokinetic evaluations in Sprague-Dawley rats, in the fed and fasted states, were also carried out for both un-milled NIF and NIF NP. [less ▲]

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See detailModulation of intestinal urea cycle by dietary spermine in suckling rat
Gharbi, Myriam ULg; Powroznik, Brigitte; Mazzucchelli, Gabriel ULg et al

in Biochemical and Biophysical Research Communications (2005), 336(4), 1119-1124

Argininosuccinate synthetase, an ubiquitous enzyme in mammals, catalyses the formation of argininosuccinate, the precursor of arginine. Arginine is recognised as an essential amino acid in foetuses and ... [more ▼]

Argininosuccinate synthetase, an ubiquitous enzyme in mammals, catalyses the formation of argininosuccinate, the precursor of arginine. Arginine is recognised as an essential amino acid in foetuses and neonates, but also as a conditionally essential amino acid in adults. Argininosuccinate synthetase is initially expressed in enterocytes during the developmental period, it disappeared from this organ then appeared in the kidneys. Although the importance of both intestinal and renal argininosuccinate synthetases has been recognised for a long time, nutrients have not yet been identified as inducers of the gene expression. In the context of a proteomic screening of intestinal modifications induced by dietary spermine in suckling rats, we showed that argininosuccinate synthetase and carbamoyl phosphate synthase disappeared from enterocytes after this treatment. The disappearance of argininosuccinate synthetase in small intestine was confirmed by immunodetection. Expression of carbamoyl phosphate synthase and argininosuccinate synthetase coding genes decreased also after spermine administration. Expression of other urea cycle enzyme coding genes was modulated by spermine administration: argininosuccinate lyase decreased and arginase increased. Our results fit with the developmental variation of argininosuccinate synthetase and carbamoyl phosphate synthase. Modulation of the gene expression for several urea cycle enzymes suggests a coordination between all the pathway steps and switch toward polyamine (or proline and glutamate) biosynthesis from ornithine. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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