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P Viallet

Publications and source records attributed to P Viallet.

64 records · Page 4Linked to original sources
PubMedDate not supplied

pHi and DNA content modifications after ADR treatment in 3T3 fibroblasts. A microfluorimetric approach.

This paper attempts to correlate morphological changes observed after ADR treatment with other cellular parameters. Experiments were carried out on control cells, ADR and cysteamine treated cells and the evaluation of DNA content and the determination of the pHi were studied using microspectrofluorimetry and Numerical Image Analysis. Results show that the DNA content and the pHi are modified significantly in presence of ADR but that no changes are observed when cells are treated with cysteamine alone. Furthermore no correlation could be established between these parameters and the class of cells that does not accumulate BaP. Further investigation will be necessary, first on other parameters such as intracellular Ca++, and second, by following parameters simultaneously on the same cell.

Animals↗
PubMedDate not supplied

MFO activity changes in single living 3T3 fibroblasts treated with adriamycin.

The effects of Adriamycin on 3T3 fibroblasts has been followed by microspectrofluorimetry. MFO activity was monitored by BaP metabolism and three points were studied: long-term ADR treatment, reversibility of this treatment and cysteamine effect on ADR treatment. The appearance of a sub-population that does not accumulate BaP suggests either a greater efflux of BaP or no penetration of the compound after ADR treatment. Moreover drastic morphological changes were observed.

Animals↗
PubMedDate not supplied

Effect of ellipticine on MFO activity in single living 3T3 fibroblasts studied by microspectrofluorimetry.

The MFO activity in intact cells was monitored through microspectrofluorimetry study of BaP metabolization. This approach allowed observation of individual cells in a cell population to represent the studied samples through histograms as a function either of rate constants or of "residual BaP". The inhibitory effect of ellipticine was demonstrated on intact living 3T3 fibroblasts. The role of DMF dissolution and cellular localisation of compounds were also studied.

Alkaloids↗
PubMedDate not supplied

Detection of human leukemia cells with multidrug-resistance phenotype using multilabeling with fluorescent dyes.

Reduced accumulation of multiple drugs is a characteristic of cells overexpressing P-glycoprotein. This phenotype is referred to as multidrug-resistance (MDR). A protocol based on reduced accumulation of fluorescent dyes is proposed for discriminating MDR cells in cell populations. The combination of three fluorescent dyes, Hoechst 33342, rhodamine 123 and Nile red, with different intracellular targets, has been designed to characterize cells with different levels of resistance, using image cytometry. The fluorescence intensity of each dye was quantified in living cells. The protocol was applied to human leukemia cell lines, (K562, K562/ADR, CCRF-CEM, CEM/VLB100, CEM/VM-1). The effect of verapamil on dye accumulation is emphasized.

Antineoplastic Agents↗
PubMedDate not supplied

Discrimination between tumour and normal cells by staining with 3,4,5,6,16,17-hexadehydro-16-(methoxycarbonyl)-19 alpha-methyl-20 alpha-oxayohimbanium: the uracil ring as a target for the specific interaction between RNA(s) and the fluorescent probe.

3,4,5,6,16,17-Hexadehydro-16-(methoxycarbonyl)-19 alpha-methyl-20 alpha-oxayohimbanium (Alstonine) is a fluorescent alcaloid which has been known to stain tumour cells more efficiently than normal ones. In this paper the spectral properties of Alstonine were first investigated and its capability for preferential staining of tumour cells verified in culture using SK-OV-3 cells as tumour cells and Mouse 3T3 fibroblasts as controls. Then interactions between Alstonine and biological macromolecules were investigated to provide the rationale for preferential labelling. Molecular filtration techniques have demonstrated that binding occurs only with RNA molecules. Similar experiments were performed with different isopolynucleotides to find an explanation for that specificity. They provide evidence that binding occurs only in the presence of a uridyl ring. This is consistent with the specificity of the linkage to RNA. As the linkage of Alstonine with RNA did not induce any shift or obvious change in the intensity of its fluorescence spectrum, it is concluded that the binding might involve the side chain of the fluorescent compound.

3T3 Cells↗
PubMedDate not supplied

Multiwavelength videomicrofluorometric study of some human leukemic lymphoblasts: effect of adriamycin on some biological parameter.

The development of multidrug resistance (MDR) in heterogeneous cell sensitive and resistant populations to a variety of clinically important cytotoxic drugs poses a major obstacle to cancer chemotherapy. The MDR phenotype is characterized by a decrease the intracellular drug accumulation and by an overexpression of the MDR1 gene which encodes the membrane protein, P-glycoprotein (Pgp). To evaluate the MDR phenotype, rationale investigations of the cytotoxic processes and effect,s of Adriamycin (ADR) were done to obtain information on individual cells. Such information could be obtained through a multiparametric approach involving multiwavelength microfluorometry and numerical image analysis on single living cells. To achieve this, cells should be simultaneously stained with Hoechst 33342 (nuclear staining), Rhodamine 123 (mitochondria staining) and Nile Red (cell contour delineation). Changes in the biological parameters accessible from R123, Ho33342 and C-SNARF-1/AM (probe used for the pHi measurements) labelling were found more informative than changes in morphological parameters for the discrimination of sensitive and resistant cells. Furthermore, this approach allows the discrimination between two resistant cell lines expressing different mechanisms of resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗