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Biomedical subjects

B Clarkson

Publications and source records attributed to B Clarkson.

At least 127 records · Page 7Linked to original sources
PubMed1978

Prophylactic heparin therapy in acute promyelocytic leukemia.

Twenty-four patients with acute promyelocytic leukemia were reviewed. Group I, treated between July 1970 and September 1973, received arabinosylcytosine and 6-thioguanine, and there was one complete remission, with 4/7 dying during induction with intracerebral hemorrhages, and 2/7 dying within one month. Group II, treated between May 1974 and March 1975, received daunomycin and arabinosylcytosine without heparin and 2/8 went into remission, with 6/8 dying during induction, 5 with intracerebral hemorrhages. Group III, treated between March 1975 and November 1976, received the identical chemotherapy as group II but with the addition of prophylactic heparin and there were 7/9 complete remissions, with 2/9 dying with intracerebral hemorrhages. In Group III there was an increased incidence of remission induction when compared to Group II (p less than .05) or when compared to Groups I and II combined (p less than .05). There was also a decreased incidence of fatal hemorrhage in Group III. This suggests that prophylactic heparin is useful during remission induction in acute promyelocytic leukemia.

Adolescent↗
PubMed1977

Cell marker analysis in acute monocytic leukemias.

Leukemic cells from nine cases of acute monocytic leukemia (AMoL) were characterized by multiple differentiation markers. Cells in most cases were phagocytic, carried an Fc receptor, and stained positively for alpha-naphthyl acetate esterase but negatively for naphthol AS-D chloroacetate esterase. However, subtle differences in marker expression were observed which suggested different degrees of leukemic cellular maturation or activation. Cell marker analysis proved to be a useful adjunct to conventional morphology in confirming the diagnosis and the recognition of the neoplastic cells in AMoL, and may ultimately provide insight into the functional state of these cells.

Esterases↗
PubMed1976

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↗
PubMed1976

Physical-chemical characterization of living cells by laser-flow microfluorometry.

A rapid method for the laser-flow microfluorometry determination of nucleic-acid content per cell is presented. A frequency distribution of fluorescence is obtained from suspensions of living cells treated with ethidium bromide directly in their own medium (or calcium-magnesium-free Hanks' balanced solution). For a fixed number of cells, a frequency distribution of fluorescence is obtained as a function of the amount of ethidium bromide progressively added to the suspension until staturation. At any ratio of added dye per unit of DNA, histograms generated from cells stained with this method give results similar to those generated after fixation and staining by the Feulgen technique, both in terms of cell-cycle phases and ploidy-level determination. The present technique requires a minimal amount of material, is instantaneous, and is conducted directly on living cells. Furthermore, dye concentration-dependence studies of mean fluorescence per cell allow determination of association constant and binding process (primary and secondary) between the intact cell and ethidium bromide. Cells which have the same amount of DNA but vary in the amount of RNA and/or chromatin conformation (like G0 and G1) can then be distinguished.

Animals↗