In this work we intended to determine whether p53 and/or retinoblastoma (Rb) tumor suppressor genes are involved at specific stages in the process of in vitro human peripheral stem cell hematopoiesis. Mononuclear peripheral blood cells were depleted of adherent cells and T lymphocytes (A-T-PMCs). Cells were then cultured in semisolid medium, under conditions that favor the growth of specific pr...

The bone marrow stromal cell population is comprised of fibroblasts, endothellal cells, fat cells and “reticular cells.” The characteristics and the regulatory role in hematopolesis of each of these cell types are unknown. A liquid culture system has been used to clone and to characterize human bone marrow fibroblast colony-forming cells (CFU-F). The linear relationship between the number of ce...

Murine bone marrow Lin-, Ly6A/E+ cells have been fractionated on the basis of rhodamine123 retention into Rh123med/hi and Rh123lo subpopulations. These populations have different responses to hemopoietic growth factors with respect to in vitro colony formation. Cells from either fraction were not stimulated by only granulocyte-colony-stimulating factor (G-CSF), granulocyte/macrophage colony-sti...

Incubation of human peripheral blood lymphocytes with bone marrow cells resulted in significant inhibition of colony formation by committed myeloid and erythroid cells. Using positively selected homogeneous natural killer (NK) cell preparations and lymphocyte subpopulations depleted of or enriched for NK cells, we definitively characterize as NK cells the cells in normal peripheral blood that a...

Spleen colony formation after transplantation of bone marrow cells into irradiated mice has been used as an assay for hematopoietic stem cells (CFU-S), but has serious limitations intrinsic to an in vivo assay. In this report we describe experiments using an in vitro clonogenic assay that is especially suitable for studies of stem cell regulation as defined growth factors and normal untreated b...

To determine the mechanism(s) by which interleukin-I (IL-I) promotes granulopoiesis in vivo, we examined the effect of in vivo administration of IL-la on colony-stimulating factor (CSF) receptor expression on bone marrow cells (BMCs) and whether this directly correlated with progenitor cell responsiveness. Administration of IL-la to mice induced the upregulation of both granulocyte-macrophage-C...

The effect of the protein kinase C (PKC) inhibitor staurosporine (ST) on the chemosensitivity of normal (colony-forming unit granulocyte-macrophage [CFU-GM]) and leukemic (acute myeloid leukemia-CFU [AML-CFU]) myeloid progenitors to daunorubicin (DNR) was evaluated. Primary colony inhibition assays allowed us to characterize two distinct groups of AML, a DNR-resistant group (patients no. 1 thro...

Hematopoietic progenitor cells (HPC) can be mobilized from CSFR–deficient mice after cyclophosphamide administration. This defect was not due to a failure to regenerate HPC the bone marrow into the peripheral circulation in response to a number of stimuli including hematopoietic growth facfollowing cyclophosphamide administration as the number of CFU-C in the bone marrow of G-CSFR–deficient mic...

We evaluated the potential role of photoradiation therapy with a benzoporphyrin derivative, monoacid ring A (BPD-MA), and dihematoporphyrin ether (DHE), for the ex vivo purging of residual tumor cells from autologous bone marrow (BM) grafts. BPD-MA and DHE photosensitizing activity was tested against two human large-cell lymphoma cell lines and colony-forming unit-leukemia (CFU-L) derived from ...