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Biomedical subjects

A Strife

Publications and source records attributed to A Strife.

52 records · Page 3Linked to original sources

Enrichment of hematopoietic progenitor cells (CFUC and BFUE) from human peripheral blood.

Granulocytic (CFUC) and erythroid (BFUE) progenitor cells have been rapidly purified from human peripheral blood approximately 140 fold by combining centrifugation on a density cushion and immunoadherence cell separation methods. An initial light density (d less than 1.071 g/cm3) mononuclear cell fraction, enriched for progenitor cells, was obtained by centrifugation of whole blood on a modified Ficoll-Hypaque density cushion. Cultures of the light-density cells gave cloning efficiencies (defined as the percentage of total cells plated) of 0.008% and 0.015% for CFUC and BFUE respectively. Further purification was achieved by negative selection whereby selective populations of immunocompetent cells were removed. Thus, B cells and monocytes (as well as up to 50% high affinity Fc receptor bearing cells) were simultaneously depleted by immunoadherence to plastic petri dishes coated with rabbit anti-human IgG. Leu-3a positive (helper) and Leu-2a positive (suppressor) T cells were then simultaneously depleted by an indirect "panning" method, whereby the T cell subsets were coated with the corresponding murine monoclonal antibodies prior to their removal by immunoadherence to plastic petri dishes coated with goat anti-mouse IgG. The final cell fraction, which contained approximately 2% of the initial light density cells were highly enriched for CFUC and BFUE, having cloning efficiencies of 0.37% (+/- 0.30) and 0.27% (+/- 0.24) respectively. Overall, the purification procedure used in the present study is relatively rapid, simple and reproducible. As such, it should provide a viable and convenient alternative approach to previously published methods for purifying hematopoietic progenitor cells from human peripheral blood.

Animals↗

Subpopulations of human peripheral blood cells: analysis of granulocytic progenitor cells by flow cytometry and immunologic surface markers.

Normal human peripheral blood cells were separated into different populations based upon isopycnic sedimentation, E rosetting, and EAC rosetting. Each population was characterized according to morphology, surface markers, granulocytic colony formation in semi-solid media, and stainable RNA content by acridine orange (AO) flow cytometry. These techniques enrich for a population of cells that is characterized by a lymphoid morphology, a high granulocytic-macrophage progenitor cell cloning efficiency, a lack of surface markers, and a high stainable RNA content not found in the other two populations of peripheral blood lymphocytes (T cells and B cells). The stainable RNA content serves as a new metabolic marker for the population of cells in which the preponderance of granulocytic progenitor cells reside.

B-Lymphocytes↗

Cell kill kinetics with hydroxyurea.

The effects of various concentrations of hydroxyurea (HU) on a human lymphoid cell line in exponential growth phase have been studied using a combination of methods, including determination of the total and viable cell counts; the cells relative DNA content, measured in a flow microfluorimeter after staining with a fluorescent Feulgen technique; the mitotic index; and the percentage of cells incorporating thymidine-3H (TdR-3H) during brief and continuous exposure to the isotope both in the presence and absence of colcemid. A significant redistribution of the cells in the various phases of the cell cycle occurred during the first 24 hr of continuous treatment with 10(-3) M and 10(-2) M HU as follows: (1) division of cells in G2; (2) depletion of mid and late S phase cells due to early cell death; (3) movement of most G1 cells at a normal rate into early S phase where they accumulate; and (4) arrest of the remaining cells in G1, which represented the surviving population after treatment for 96 hr or longer. After removal of the drug, the cell fraction blocked in early S phase progressed semisynchronously through S, but many of the cells were unable to complete division. Their capacity to recover depended on the drug concentration and duration of exposure, but in general the cellular injury caused by HU was more reversible than that caused by "equivalent" concentrations of arabinosylcytosine.

Cell Count↗