References of "Willemsen, Philippe"
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See detailPretreatment of adult bone marrow mesenchymal stem cells with cardiomyogenic growth factors and repair of the chronically infarcted myocardium
Bartunek, Joseph; Croissant, J. D.; Wijns, William et al

in American Journal of Physiology - Heart and Circulatory Physiology (2007), 292(2), 1095-1104

The in vivo cardiac differentiation and functional effects of unmodified adult bone marrow mesenchymal stem cells (MSCs) after myocardial infarction (MI) is controversial. We postulated that ex vivo ... [more ▼]

The in vivo cardiac differentiation and functional effects of unmodified adult bone marrow mesenchymal stem cells (MSCs) after myocardial infarction (MI) is controversial. We postulated that ex vivo pretreatment of autologous MSCs using cardiomyogenic growth factors will lead to cardiomyogenic specification and will result in superior biological and functional effects on cardiac regeneration of chronically infarcted myocardium. We used a chronic dog MI model generated by ligation of the coronary artery (n = 30). Autologous dog bone marrow MSCs were isolated, culture expanded, and specified into a cardiac lineage by adding growth factors, including basic FGF, IGF-1, and bone morphogenetic protein-2. Dogs underwent cell injection > 8 wk after the infarction and were randomized into two groups. Group A dogs (n = 20) received MSCs specified with growth factors (147 +/- 96 x 10(6)), and group B (n = 10) received unmodified MSCs (168 +/- 24 x 10(6)). After the growth factor treatment, MSCs stained positive for the early muscle and cardiac markers desmin, antimyocyte enhancer factor-2, and Nkx2-5. In group A dogs, prespecified MSCs colocalized with troponin I and cardiac myosin. At 12 wk, group A dogs showed a significantly larger increase in regional wall thickening of the infarcted territory (from 22 +/- 8 to 32 +/- 6% in group A; P < 0.05 vs. baseline and group B, and from 19 +/- 7 to 21 +/- 7% in group B, respectively) and a decrease in the wall motion score index (from 1.60 +/- 0.05 to 1.35 +/- 0.03 in group A; P < 0.05 vs. baseline and group B, and from 1.58 +/- 0.07 vs. 1.56 +/- 0.08 in group B, respectively). The biological ex vivo cardiomyogenic specification of adult MSCs before their transplantation is feasible and appears to improve their in vivo cardiac differentiation as well as the functional recovery in a dog model of the chronically infarcted myocardium. [less ▲]

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See detailEnhancement of steroid receptor-mediated transcription for the development of highly responsive bioassays
Willemsen, Philippe; Scippo, Marie-Louise ULg; Maghuin-Rogister, Guy ULg et al

in Analytical and Bioanalytical Chemistry (2005), 382(4), 894-905

We have previously generated several transformed human mammary cell lines for the detection of steroid receptor-mediated activities and used these cell lines to detect and characterize steroid hormone ... [more ▼]

We have previously generated several transformed human mammary cell lines for the detection of steroid receptor-mediated activities and used these cell lines to detect and characterize steroid hormone (ant)agonistic compounds. In this report, we describe the specific optimization procedures used to enhance receptor-mediated transcription through the human glucocorticoid, progesterone and androgen receptors, respectively. Sodium arsenite-induced chemical stress leads to a substantial and specific increase in the glucocorticold receptor-mediated transcription, resulting in maximal stimulations of more than 2000-fold by the agonist dexamethasone. Similarly, a combined treatment with forskolin (an activator of adenylate cyclase) and trichostatin A (an inhibitor of histone deacetylases) leads to a synergistic enhancement of progesterone or androgen stimulation, resulting in a maximal induction of more than 200-fold or about 100-fold, respectively. The enhanced responses to specific steroids are mediated by the corresponding nuclear receptor. We show that by using these enhanced transcriptional stimulation protocols, it is possible to detect lower amounts of steroid hormones without substantially affecting the relative biological activities of various agonists. Finally, the application of these enhanced reporter cell assays to real biological samples from meat-producing animals is evaluated, and some validation parameters are presented. [less ▲]

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See detailUse of reporter cell lines for detection of endocrine-disrupter activity
Willemsen, Philippe; Scippo, Marie-Louise ULg; Kausel, G. et al

in Analytical and Bioanalytical Chemistry (2004), 378(3), 655-663

We have studied stable transformed human mammary cell lines with highly inducible steroid receptor-mediated luciferase reporter gene expression. Cells responding specifically to glucocorticoids ... [more ▼]

We have studied stable transformed human mammary cell lines with highly inducible steroid receptor-mediated luciferase reporter gene expression. Cells responding specifically to glucocorticoids, progestagens, androgens, or estrogens are described and characterized. The use of this high-throughput, cell-based assay for analysis of steroid (ant)agonists is reported. Systematic characterization of endocrine-disrupting activity on human receptors and in a human-cell system is interpreted for a selection of xenobiotics. We show that the phytoestrogens apigenin and genistin have progestagenic and androgenic activity, respectively. Finally, application of cell-based assays to the analysis of environmental samples is discussed. [less ▲]

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See detailRecombinant human estrogen, androgen and progesterone receptors for detection of potential endocrine disruptors
Scippo, Marie-Louise ULg; Argiris, Catherine; Van de Weerdt, Cécile ULg et al

in Analytical and Bioanalytical Chemistry (2004), 378(3), 664-669

This work reports the binding capacity of various chemicals (so-called endocrine disruptors) to recombinant human steroid receptors (hERalpha, hPR and hAR). The tested chemicals are organochlorine ... [more ▼]

This work reports the binding capacity of various chemicals (so-called endocrine disruptors) to recombinant human steroid receptors (hERalpha, hPR and hAR). The tested chemicals are organochlorine insecticides (DDT and its metabolites, methoxychlor, aldrin, dieldrin, chlordecone, lindane, trichlorobenzene), estrogenic insecticides (endosulfan, toxaphene, nonachlor), herbicides (alachlor and atrazine), fungicides (benomyl and vinclozolin), industrial chemicals (nonylphenol, bisphenol A, diphenylphtalate), antioxidants (butylated hydroxyanisol) and some phytoestrogens. Except for phytoestrogens, most of the tested chemicals (DDT and its metabolites, aldrin, alpha- and beta-endosulfan, toxaphen, trans-nonachlor) show higher affinities for hPR than for hERalpha, indicating that the interaction with the progesterone receptor could contribute to the endocrine-disrupting effects imputed to these chemicals. We propose to use binding assays using recombinant human steroid receptors as screening tools for the detection of endocrine disruptors in various samples. [less ▲]

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See detailReceptor-based screening assays: New perspectives in anti-doping control
Scippo, Marie-Louise ULg; Willemsen, Philippe; Danyi, Sophie ULg et al

in Chromatographia (2004), 59(Suppl. S), 23-27

The so-called "growth promoters", steroid hormones and beta-agonists, are currently controlled by using hyphenated analytical methods (chromatography coupled to mass spectrometry) or, sometimes for ... [more ▼]

The so-called "growth promoters", steroid hormones and beta-agonists, are currently controlled by using hyphenated analytical methods (chromatography coupled to mass spectrometry) or, sometimes for screening purposes, on immunoassays. These methods are often too specific to allow an effective multianalyte control. To develop more efficient assays, the use of hormonal receptors as detection tools (receptor-based binding assays and cell-based assays) is proposed. Receptor-based assays represent useful tools in screening of hormonal residues in food, but they could also be applied in doping control (to detect "new" hormonal substances). Furthermore, these assays could be used to monitor the human exposure to endocrine disruptors. [less ▲]

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See detailUse of specific bioluminescent cell lines for the detection of steroid hormone (ant)agonists in meat producing animals
Willemsen, Philippe; Scippo, Marie-Louise ULg; Maghuin-Rogister, Guy ULg et al

in Analytica Chimica Acta (2002), 473(1-2), 119-126

We present stable transformed human mammary cell lines displaying highly inducible steroid receptor-mediated luciferase reporter gene expression. The utilization of a cell-based assay for detection of ... [more ▼]

We present stable transformed human mammary cell lines displaying highly inducible steroid receptor-mediated luciferase reporter gene expression. The utilization of a cell-based assay for detection of steroid agonists and antagonists down to 0.3 ng g(-1) is described and its application to the analysis of bovine samples is discussed. In particular, the use of the assays to detect illegal progesterone or androgen treatment has to take into account the presence of natural endogenous hormones. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailDetection of illegal growth promoters in biological samples using receptor binding assays
Scippo, Marie-Louise ULg; Van de Weerdt, Cécile ULg; Willemsen, Philippe et al

in Analytica Chimica Acta (2002), 473(1-2), 135-141

In the European Union (EU), the use of growth-promoting substances in meat production is banned. The control of growth promoters, especially steroid hormones, is presently based on expensive and time ... [more ▼]

In the European Union (EU), the use of growth-promoting substances in meat production is banned. The control of growth promoters, especially steroid hormones, is presently based on expensive and time-consuming chromatographic methods of analysis or, sometimes, for screening purposes, on radio- or enzyme-immunoassays, all of which are often too specific to allow effective multi-analyte control. In order to develop rapid and inexpensive multi-analyte detection tests, we proposed the use of hormonal receptors as detection tools. The system described here (radio-receptor assays) is based on a direct bindin g assay of steroid hormones to their respective receptors. Human receptors to estrogens (hERalpha), androgens (hAR), progestagens (hPR) and glucocorticoids (hGR) have been produced by genetic engineering in bacteria or in eucaryotic cells. Binding analyses revealed that the obtained receptor proteins retained a high affinity for their corresponding native ligand. In addition, competition studies continued that each of the four receptors displays a specificity profile for a series of analogs in agreement with the literature. Finally, the stability of these recombinant receptors is sufficient to allow their use in test kits. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailReceptors as screening tools in the detections of hormones. Applications in the control of meat production
Maghuin-Rogister, Guy ULg; Baise, Etienne ULg; Carpeaux, Rudy et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (1999), 4(1), 21-22

Detailed reference viewed: 41 (11 ULg)