We found that human bone marrow cells formed mononuclear phagocyte clusters and colonies in liquid culture with or without conditioned medium. In this study, we prepared media from human spleen or bone marrow cells in several different conditions and assessed their colony-stimulating activities as well as the sensitivities of human spleen or bone marrow colony-forming cells to these conditioned...

The hemopoietic cells from anemic mice of genotype WW are less able by 200-fold to take part in colony formationin the spleen than cells from the normal littermates of genotype ww. The genetic defect shows itself in the colony-forming cells, since cells from normal littermate mice formcolonies in the spleens of unirradiated mice of genotype WW. Use of animals of genotype WVVWT as recipients imp...

Granulocyte and macrophage precursors (GM-CFU-C-), which differentiate in vitro without added granulocyte and macrophage colony stimulating factor (GM-CSF), can be detected in the hematopoietic organs of mice infected with myeloproliferative sarcoma virus (MPSV). Retransplantation experiments have shown that the GM-CFU-C- are incapable of autonomous growth and depend on a factor present in medi...

The mechanism of neutropenia in Felty's Syndrome (FS) was tested. The suppressor capacity of mononuclear cells from patients with FS on normal bone marrow granulopoiesis was tested by the in vitro colony forming unit in culture assay. Peripheral blood, bone marrow, and spleen cells from FS patients with marked neutropenia (less than 1,000 neutrophils/mm3) suppressed the colony forming unit in c...

The colony-forming unit culture (CFU-C) in the thin-layer agar colony technique is considered to be representative for hemo-poietic stem cells (HSC), according to our studies in mouse and monkey bone marrow. Using this in vitro assay as a guide, stem cell concentrates were prepared from monkey and human bone marrow by repeated density gradient centnfugation. The number of CFU-C could be enriche...

In a study of the components of antiserum prepared (in S I M / M c K mice) against formalinized Friend leukemic cell suspensions, the spleen focus assay method was employed for measuring the kinetics of virus neutralization, and the spleen colony method was used to monitor the loss of tumor colonyforming ability during the cytotoxic reaction. Repeated absorption of Friend antiserum with resuspe...

Constitutive activation of FMS-like tyrosine kinase 3 (FLT3) by internal tandem duplication (ITD) mutations is one of the most common molecular alterations known in acute myeloid leukemia (AML). To investigate the role FLT3/ITD mutations play in the development of leukemia, we generated a FLT3/ITD knock-in mouse model by inserting an ITD mutation into the juxtamembrane domain of murine Flt3. FL...

The viability of cryopreserved mouse fresh and postmortem bone marrow cells was studied using methylcellulose clonal cell culture assay and the murine spleen colony technique. This study clearly indicates the presence of pluripotent hemopoietic stem cells in cryopreserved murine postmortem bone marrow cells. The viability of granulocytic precursors in both fresh and postmortem bone marrow cells...

Long-term murine bone marrow cultures were used to support the growth and development of hematopoietic cells. After hematopoiesis was established. the cultures were infected with a recombinant murine amphotropic virus carrying the avian sarcoma virus src gene and the CFU-S kinetics were examined. The CFU-S from the srcinfected cultures displayed a reduced seeding efficiency in the standard sple...