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  • 1
    ISSN: 1432-0584
    Keywords: Retinoic acid ; Bone marrow ; Progenitors ; CD 34 ; Hematopoiesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of both 13-cis-and all-trans retinoic acid (RA) on colony formation of normal bone marrow (BM) progenitors were investigated in semi-solid (methylcellulose) assays, using either isolated CD 34+ cells or BM mononuclear cells. Single cell liquid cultures were performed to further discriminate between direct and indirect effects. RA action results in significant decrease of colony forming units (CFUs). This effect is more pronounced starting from CD 34+ progenitors than starting from total BM. This overall decrease in CFUs is due to selective inhibition of CFU-M (macrophage) and erythroid colonies (BFU-E). At the single cell level the CFU-M inhibition is confirmed with — in addition — a significant inhibition of CFU-GM (granulocyte-macrophage) and a marked stimulation of CFU-G(granulocyte)s. Both retinoids exert the above-mentioned effects. All-trans RA, however, is effective at a tenfold lower concentration (10−7 M) than 13-cis RA (10−6 M). Results on CD 34+ BM fractions (substantially reduced in accessory cells) demonstrate that the described effects can probably be attributed to the direct action of RA on these progenitors; single progenitor (CD 34+) cell liquid cultures further prove this point.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0584
    Keywords: Keywords Haematopoiesis ; sIL-6R/IL-6 complex ; CD34+CD38 ; Pre-CFU ; gp130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  It has previously been shown that gp130 and c-kit signalling synergize for the ex vivo expansion of human cord blood (CB) CD34+ haematopoietic progenitor cells. We were interested in evaluating this synergy within an ontogenetically different haematopoietic tissue [i.e. adult bone marrow (BM)] and on a more primitive progenitor subset (i.e. CD34+CD38– cells), which are highly enriched for pre-colony forming unit (CFU) cells. These cells were plated out in a primary liquid culture supplemented with either interleukin (IL)-6+stem cell factor (SCF), IL-6+SCF+soluble IL-6 receptor (sIL-6R), IL-6+SCF+sIL-6R+IL-3+IL-1 or SCF+IL-3+IL-6+IL-1. Cell counting after liquid culture revealed an absolute expansion of 2.2-, 4.1-, 89.5- and 65.7-fold compared with initial cell input for the four-cytokine combinations, respectively. The secondary read-out assay revealed that this cell expansion in the liquid culture also resulted in CFU generation, with absolute cloning efficiencies of 0.002, 0.024, 12.13 and 7.73 (per cell initially present) for the respective cytokine combinations. These results indicate that gp130 and c-kit signalling alone (i.e. using IL-6+SCF+sIL-6R), in terms of both cell number and CFU generation, insufficiently stimulate primitive adult BM CD34+CD38– haematopoietic cells in order to reach a CFU generation comparable with that obtained after multifactor stimulation. Adding sIL-6R to the multifactor stimulation and compared with this multifactor stimulation, a 1.7-fold synergy in terms of cell expansion and a 3.0-fold synergy in terms of CFU generation are obtained. The sIL-6R/IL-6 complex thus has a narrower spectrum of action on primitive adult BM CD34+CD38– cells than on CB CD34+ cells.
    Type of Medium: Electronic Resource
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