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A Fourcade

Publications and source records attributed to A Fourcade.

At least 37 records · Page 2Linked to original sources
PubMed1982

Comparative uptake of adriamycin and daunorubicin in sensitive and resistant friend leukemia cells measured by flow cytometry.

Based on the fluorescence properties of adriamycin (ADM) and daunorubicin (DNR), uptake in sensitive and resistant Friend leukemia cells (FLC) was studied with the aid of the fluorescence activated cell sorter (FACS II). A quantitative cell by cell fluorescence intensity analysis showed a differential affinity of FLC to ADM and DNR. The cellular uptake of these two drugs was temperature dependent and was not hindered by sodium azide treatment; incorporation into isolated nuclei was not temperature dependent, nor hindered by sodium azide. Friend leukemia cell variants resistant to adriamycin (ADM-RFLC) and to daunorubicin (DNR-RFLC) were developed. The rate of uptake of ADM and DNR across the plasma membrane of these two cell variants was lower than in sensitive cells. Although these cells were crossresistant to both ADM and DNR, the drug-induced fluorescence intensity was distributed differently in the corresponding resistant cell variants. We suggest therefore that resistant is the consequence of changes induced in the plasma membrane components. These changes may differ according to which drug is used.

Animals↗
PubMed1982

Uptake, efflux, and hydrolysis of aclacinomycin A in Friend leukemia cells.

The kinetics of uptake by cells and nuclear incorporation of aclacinomycin A was studied in Friend leukemia cells. It was shown that uptake is a very rapid process. The intracellular concentration is maximum in 10 min and mainly (about 75%) localized in the nucleus. Most of the incorporated drug will disappear from the cell by a two-step mechanism: (a) efflux from the nucleus to the cytoplasm; and (b) deglycosidation at C-7 to the alkavinone form in the cytoplasmic fraction. The cellular uptake was temperature dependent but was not prevented by sodium azide treatment. We assumed, therefore, that it is related to the composition and to the dynamic structure of the cell surface membrane. Nuclear outward transport and deglycosidation were inhibited by sodium azide and low temperatures; this suggests that they are regulated by an active transport process and by an enzymatic activity, respectively.

Aclarubicin↗
PubMed1981

The effect of hexamethylene-bis-acetamide on multiparameter analysis of Friend leukemia cells.

Friend leukemia cells were induced to differentiate by hexamethylene-bis-acetamide (HMBA). The relationship between cell growth cell volume distribution, fluorescence intensity and fluorescence anisotropy of the membrane probe 1,6 diphenyl 1,3,5 hexatriene (DPH) was analyzed in differentiated and undifferentiated cells with the aid of the fluorescence activated cell sorter (FACS II). The induction of a differentiated state was associated with a decrease in cell volume and an increase of fluorescence anisotrophy. The inhibition of this induction by dexamethasone prevented the decrease of cell volume without affecting the increase of fluorescence anisotropy. We conclude therefore that the high degree of anisotropy is not correlated to the differentiated state nor with the volume of the cells.

Acetamides↗
PubMed1980

Membrane dynamics of Friend leukaemic cells. I. Changes associated with cell growth.

The relationship between membrane dynamics and cellular growth of Friend leukaemic cells (FLC) was studied by fluorescence polarization (P) using diphenyl hexatriene (DPH). The P-value changes as a function of the state of the cells being maximum in the growing state. The P-value is also influenced by serum concentration and this effect appears to be a passive process.

Animals↗
PubMed1980

Membrane dynamics of Friend leukaemic cells. II. Changes associated with cell differentiation.

In a previous study, using fluorescence polarization (P) with diphenyl hexatriene (DPH), it was shown that growing and resting cells have different P-values. This property has now been used to investigate the membrane action of dimethylsulfoxide (DMSO) and hexamethylene bisacetamide (HMBA), two inducers of Friend leukaemic cell (FLC) differentiation. Both an inducible cell line (FLC) and a resistant variant cell line (RFLC), had the same characteristics regarding P-values. During the differentiation process in the FLC cell line, further changes in P-values were observed. In the resistant cell line, these changes in P-value were not seen. This suggests that these inducers of differentiation are acting at the cell membrane.

Acetamides↗
PubMed1980

[Changing relative proportions of apolipoproteins of VLDL in chronic male alcoholics (author's transl)].

Apoproteins of very low density lipoproteins of plasma from male chronic alcoholics and healthy men serving as controls were investigated. VLDL were delipidated using diethyl ether-ethanol and were separated by polyacrylamide gel electrophoresis. The average relative concentration of apo Cll, Clll1 and Clll2 are investigated. The proportion of apo Cll is reduced, and that of apo Clll increased (particularly Clll1) in male chronic alcoholics compared to the normal and the ratio of apo Clll1 to apo cll was significantly increased. The Cll/Clll1 + Clll2 ratio is highly significantly reduced in patients. Changes in apo Clll1/Cll ratio in relation to hypertriglyceridaemia are envisaged. Furthermore apo Cll is believed to activate and apo Clll to inhibit lipoprotein lipase activity "in vitro".

Adult↗
PubMed1975

Binding studies of NADPH to NADP-specific L-glutamate dehydrogenase from Saccharomyces cerevisiae.

Optical characteristics of enzyme-reduced coenzyme complexes of yeast NADP-specific glutamate dehydrogenase have been investigated in the presence and absence of product (L-glutamate) and in the presence or absence of phosphate. The phosphate effect, pointed out in a previous work, is found again: inorganic phosphate (Pi) destabilizes the binary complex (E - NADPH), the dissociation constant of which is equal to 14 muM, a value much higher than that determined in Tris-HCl buffer: Kd = 0.9 muM. Concerning the role of phosphate some assumptions are drawn up with respect to a similar behaviour of Pi toward yeast glutamate dehydrogenase and ADP toward the beef liver enzyme. In the same way, L-glutamate induces a stabilization of the binary complex; this latter effect is unchanged in the presence of phosphate, yet it is less marked than in the case of beef liver glutamate dehydrogenase. Protein fluorescence, nucleotide fluorescence and circular dichroism measurements allowed the determination of three identical and independent NADPH binding sites per hexameric active unit. In analogy with beef liver enzyme, it seems that yeast glutamate dehydrogenase is a good model to study anticooperativity in ligand binding.

Binding Sites↗
PubMed1974

Transfection of chicken embryo cells with DNA extracted from avian virus-producing neoplastic cells.

DNA isolated from avian virus-producing leukemic myeloblasts induced the production of viruses, but not morphological transformation, in cultivated chicken fibroblasts. The recovered virus had the same biological characteristics as the original avian myeloblastosis virus (AMV) and produced myeloblastosis and nephroblastomas when injected into chickens. Neutralization experiments with chicken anti-AMV-BAI strain A sera showed an antigenic community between the DNA-transfected virus and the original virus. Virus induced in fibroblasts after treatment with DNA from a viral nephroblastic nephroblastoma line only gave nephroblastoma when injected into chicken. Treatment of chicken embryo cells with DNA extracted from normal chicken embryos did not induce viral production.

Animals↗