Showing papers by "Walter Berger published in 1998"
TL;DR: A bioassay developed for the specific detection of functional P-gp levels and the efficacy of related chemosensitizers (CD-P-gp-assay), based on the flow cytometric measurement of changes in the > or = G2M cell cycle compartment, which shows a significant correlation between cytokinesis-blocking CD doses.
Abstract: The functional contribution of both P-glycoprotein (P-gp) and the multidrug resistance-associated protein (MRP) to multidrug resistance (MDR) in tumor cells is commonly determined by drug cytotoxicity and/or accumulation/efflux tests. We report on a bioassay developed for the specific detection of functional P-gp levels and the efficacy of related chemosensitizers (CD-P-gp-assay). The assay is based on the flow cytometric measurement of changes in the HG2M cell cycle compartment which are due to the induction of polykaryons after exposure of proliferating cells to three defined cytochalasin D (CD) concentrations with and without verapamil. As demonstrated in 13 well-characterized MDR cell models (20 resistant sublines), there is a significant correlation between cytokinesis-blocking CD doses, as well as responsiveness to chemosensitizers and MDR1 gene expression (mRNA and P-gp) allowing discrimination between different levels of P-gpMDR. CD-P-gp-assay specificity was assessed by testing 23 compounds: 19 known as potent inhibitors of P-gp-MDR, some of them, though to a lesser extent, also of MRP-MDR; 1 inhibiting MRP-but not P-gpMDR; 3 inactive in both types of MDR. A modulation of CD activity was confined exclusively to both P-gp-expressing cell lines and P-gp chemosensitizers. CD cytoskeletal activity measured by FACS is a specific and sensitive tool with which to detect functional P-gp and related chemosensitizers. Cytometry 31:187‐198, 1998. r 1998 Wiley-Liss, Inc.
19 citations
TL;DR: The incidence has been increasing steadily during the past three decades (world-wide projected 100,000 cases by the year 2000), however, it seems to slow down during the last few years.
Abstract: the epidermis [2]. Despite intense scientific efforts made, both etiology and causative reasons for the development of MM are still widely unknown. The incidence has been increasing steadily during the past three decades (world-wide projected 100,000 cases by the year 2000), however, it seems to slow down during the last few years (as reported on the 4th World Abteilung Angewandte und Experimentelle Onkologie, Institut für Tumorbiologie – Krebsforschung, Universität Wien
7 citations