Therapeutic concentrations of cyclosporine A, but not FK506, increase P-glycoprotein expression in endothelial and renal tubule cells

Therapeutic concentrations of cyclosporine A, but not FK506, increase P-glycoprotein expression in endothelial and renal tubule cells.BackgroundThe immunosuppressive drugs cyclosporine A (CsA) and tacrolimus (FK506) are extruded from cells by the multidrug resistance P-glycoprotein (P-gp), an efflux pump for drugs and xenobiotics, which may limit their therapeutic effectiveness and/or incidence of toxic side effects. In the present study, we investigated the effect of therapeutic concentrations of CsA and FK506 on the expression of P-gp in cultured endothelial and proximal tubule cells.MethodsP-gp expression in human arterial endothelial (HAEC) and rat proximal tubule cells (RPTC) was determined by immunoblotting and immunocytochemistry, and correlated with P-gp-mediated transport by measuring the intracellular accumulation of the fluorescent probe calcein.ResultsFollowing incubation of HAEC with therapeutic concentrations of 0.1 to 1.6 μm CsA up to seven days, P-gp expression increased in a time- and concentration-dependent manner, maximally to 291 ± 42% of controls with 0.8 μm CsA for seven days. Similar effects of CsA were observed in RPTC. In contrast, therapeutic concentrations of FK506 (0.01 to 0.2 μm up to 7days) did not change P-gp expression in either cell type, though at higher, supratherapeutic concentrations of FK506 (0.6 to 1.2 μm) P-gp expression was also increased. Immunocytochemistry revealed increased P-gp expression in the plasma membrane of HAEC and RPTC treated with 0.8 μm CsA, which was reflected by a decrease of P-gp-mediated accumulation of calcein in both cell types.ConclusionsThe data suggest that the induction of P-gp expression in HAEC and RPTC at concentrations of CsA or FK506 above 0.5 μm is part of the protective answer of cells to toxic concentrations of the drugs and could therefore interfere with the therapeutic effectiveness of CsA in vivo

Une décision de l’organe de règlement des différends de l’OMC. Quels impacts pour la protection internationale des indications géographiques ?

L’analyse des recommandations de l’Organe de Règlement des Différends de l’Organisation Mondiale du Commerce portant sur le système européen de protection des appellations d’origine et des indications géographiques (pour les produits agroalimentaires hors vins et spiritueux) permet d’esquisser des perspectives d’évolution dans ce domaine pour les prochaines années, tant au niveau européen qu’au niveau multilatéral.The analysis of the recommendations given by the Dispute Settlement Body of the World Trade Organization on the European system of protection for appellations of origin and geographical indications (for agro-food products except wines and spirits) allows us to draw possible scenarios for the future development in this field, both at European and multilateral levels

Cadmium induces Wnt signaling to upregulate proliferation and survival genes in sub-confluent kidney proximal tubule cells

<p>Abstract</p> <p>Background</p> <p>The class 1 carcinogen cadmium (Cd²⁺) disrupts the E-cadherin/β-catenin complex of epithelial adherens junctions (AJs) and causes renal cancer. Deregulation of E-cadherin adhesion and changes in Wnt/β-catenin signaling are known to contribute to carcinogenesis.</p> <p>Results</p> <p>We investigated Wnt signaling after Cd²⁺-induced E-cadherin disruption in sub-confluent cultured kidney proximal tubule cells (PTC). Cd²⁺(25 μM, 3-9 h) caused nuclear translocation of β-catenin and triggered a Wnt response measured by TOPflash reporter assays. Cd²⁺reduced the interaction of β-catenin with AJ components (E-cadherin, α-catenin) and increased binding to the transcription factor TCF4 of the Wnt pathway, which was upregulated and translocated to the nucleus. While Wnt target genes (<it>c-Myc</it>, <it>cyclin D1 </it>and <it>ABCB1</it>) were up-regulated by Cd²⁺, electromobility shift assays showed increased TCF4 binding to <it>cyclin D1 </it>and <it>ABCB1 </it>promoter sequences with Cd²⁺. Overexpression of wild-type and mutant TCF4 confirmed Cd²⁺-induced Wnt signaling. Wnt signaling elicited by Cd²⁺was not observed in confluent non-proliferating cells, which showed increased E-cadherin expression. Overexpression of E-cadherin reduced Wnt signaling, PTC proliferation and Cd²⁺toxicity. Cd²⁺also induced reactive oxygen species dependent expression of the pro-apoptotic ER stress marker and Wnt suppressor CHOP/GADD153 which, however, did not abolish Wnt response and cell viability.</p> <p>Conclusions</p> <p>Cd²⁺induces Wnt signaling in PTC. Hence, Cd²⁺may facilitate carcinogenesis of PTC by promoting Wnt pathway-mediated proliferation and survival of pre-neoplastic cells.</p

A case study in statistical testing of reusable concurrent objects

Abstract. A test strategy is presented which makes use of the information got from OO analysis and design documents to determine the testing levels (unit, integration) and the associated test objectives. It defines solutions for some of the OO testing issues: here, emphasis is put on applications which consist of concurrent objects linked by client-server relationships. Two major concerns have guided the choice of the proposed techniques: component reusability, and nondeterminism induced by asynchronous communication between objects. The strategy is illustrated on a control program for an existing production cell taken from a metal-processing plant in Karlsruhe. The program was developed using the Fusion method and implemented in Ada 95. We used a probabilistic method for generating test inputs, called statistical testing. Test experiments were conducted from the unit to the system levels, and a few errors were detected

The optimisation of stochastic grammars to enable cost-effective probabilistic structural testing

Abstract The effectiveness of statistical testing, a probabilistic structural testing strategy, depends on the characteristics of the probability distribution from which test inputs are sampled. Metaheuristic search has been shown to be a practical method of optimising the characteristics of such distributions. However, the applicability of the existing search-based algorithm is limited by the requirement that the software’s inputs must be a fixed number of ordinal values. In this paper we propose a new algorithm that relaxes this limitation and so permits the derivation of probability distributions for a much wider range of software. The representation used by the new algorithm is based on a stochastic grammar supplemented with two novel features: conditional production weights and the dynamic partitioning of ordinal ranges. We demonstrate empirically that a search algorithm using this representation can optimise probability distributions over complex input domains and thereby enable cost-effective statistical testing, and that the use of both conditional production weights and dynamic partitioning can be beneficial to the search process