Human umbilical cord blood cells from 26 were formed in these cultures per 2 x newborn infants and peripheral blood cells i0 nucleated cells plated. The peripheral from 18 adults were cultured in vitro by blood cell cultures from adults gave rise to using the agar-gel method of human 0-1 1 colonies, with a mean of 3, per 2 x hemopoietic cell culture. An increased i0 nucleated cells plated. The ...

BACKGROUND The small Rho GTPases Rac1 and Rac2 have both overlapping and distinct roles in actin organization, cell survival, and proliferation in various hematopoietic cell lineages. The role of these Rac GTPases in erythropoiesis has not yet been fully elucidated. DESIGN AND METHODS Cre-recombinase-induced deletion of Rac1 genomic sequence was accomplished on a Rac2-null genetic background,...

In semisolid agar cultures containing mercaptoethanol, cells from the spleen, lymph nodes, marrow, peritoneal cavity, thoracic duct, and blood of normal mice generated clusters and colonies of up to 3,000 cells. Colony numbers and growth were markedly enhanced by the addition of sheep red cells. The frequency of colony-forming cells in the spleen or lymph nodes was 0.5-2.0%, and cluster forming...

Granulocyte colony-stimulating factor (G-CSF) stimulates the proliferation and restricted differentiation of hematopoietic progenitors into neutrophils. To clarify the effects of G-CSF on hematopoietic progenitors, we generated transgenic (Tg) mice that had ubiquitous expression of the human G-CSF receptor (hG-CSFR). In clonal cultures of bone marrow and spleen cells obtained from these mice, h...

ultrasonography is a useful procedure in evaluation of spleen size in different clinical conditions. in this study, we used it to evaluate spleen size in patients with various heptologic, hematologic and autoimmune diseases. to express spleen size, a spleen index (si), the product of the transverse diameter and its perpendiculr diameter measured on the maximum-sectional image of the spleen, was...

The mechanism of spleen colony formation in nonirradiated mice was investigated. When the spleen cells of C57BL mice immunized against CBA-T6T6 mice were injected into the nonirradiated BT6F1 (C57BL X CBA-T6T6) hybrid mice, the number of hematopoietic stem cells (CFU-S of C57BL mouse origin that settled in the spleen of the BT6F1 mice continued to decrease in the first 9 days and then started t...

Mouse stromal cell lines (MSS lines) have been established from the spleens of newborn mice in culture at a low serum concentration. These MSS lines support the proliferation and differentiation of the erythroid progenitor cells from mouse fetal livers and bone marrow in a semisolid medium in the presence of erythropoietin. Larger colonies of over 1,000 benzidine-positive erythroid cells were d...

Murine bone marrow and adherence-separated spleen cells cultured on hydrophobic, gas-permeable Teflon foils (petriperm dishes) can be shown to synthesize and secrete erythropoietin (Epo) and colony-stimulating activity (CSA) simultaneously into the surrounding medium. The Epo activity in the supernatants of primary cultures as measured by the fetal liver erythroid colony-forming technique, from...

Mice were irradiated repetitively at 6 wk intervals. The proliferative capacity of the hematopoietic stem cell compartment was studied after each irradiation and compared to that of age-matched controls which had been irradiated only once. Hematopoietic proliferation capacity was measured by determining the number of spleen colonies, splenic iron uptake, spleen weight, and volume of packed red ...