Raphael Jacquot

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Human K562 leukemia cells have been induced to differentiate along the erythroid lineage by aclacinomycin (ACM), an anthracyclic antitumor drug. During differentiation over 3 days in culture, the expression and the nature of erythropoietin (EPO) receptors have been analyzed using 125I-labeled bioactive recombinant human EPO. Aclacinomycin at 20 nM, the(More)
Commercially available 125I-labeled erythropoietin, obtained by genetic engineering from a human gene, was used to characterize receptors for this hormone on the cell surface of rat erythroid progenitor cells. A low number of high affinity binding sites (487 +/- 32 sites/cell, Kd = 167 +/- 14 pm) were found. Nonerythroid cells and erythrocytes did not(More)
Murine erythroleukaemia cells represent erythroid precursors blocked near the CFU-E or proerythroblast stage. In contrast to their non-leukaemic equivalents, neither their proliferation nor their differentiation seems to be affected by erythropoietin. However, we show in this paper that both uncommitted and committed, benzidine-positive, cells bind(More)
The number of haematopoietic cells per unit of volume decreases after day 18 and falls rapidly until day 21. On day 21 it is reduced by three quarters as compared to the day 17 value. Maternal laparotomy causes, in the 24 h period following the operation, an anticipated and accelerated decrease. This effect is prevented by previous adrenalectomy. After(More)
Erythropoietic activity of foetal rat femoral marrow was examined during the last four days of intra-uterine life. Insignificant at day 18, it develops slowly thereafter until birth. In the non-suckled neonate (not older than two hours), it appears notably enhanced. In order to test the potential of the foetal marrow to develop precocious or increased(More)
Erythroid progenitor cells were obtained from rat fetal liver by immunolysis of the whole erythroid population with an antiserum directed against adult rat erythrocytes, followed by separation on a density gradient. Immediately after their isolation, these cells contained only minute amounts of globin mRNAs and their heme synthesis was negligible. In the(More)
The human leukemic cell line K 562 can be induced to differentiate along the erythroid lineage by various chemical compounds and particularly by the anthracyclic antitumor drug, adriamycin (ADR). In this study, we show that, in the presence of a subtoxic concentration of ADR (30 nM), the appearance of hemoglobin-producing K 562 cells is associated with a(More)