Sister chromatid exchanges in human lymphocytes treated in vitro with cadmium in G(0) and S phase of their cell cycles

Sister chromatid exchanges (SCEs) were analyzed in human phytohemagglutinin-activated peripheral lymphocyte cultures exposed to varying concentrations (10(-7)-10(-3) M) of cadmium chloride in vitro at two different stages of the cell cycle, G(0) and early S phase. When cadmium chloride was administered at the G(0) phase, no increase in the SCEs were observed for the doses 10(-6) and 10(-5) M. Concentrations equal to or larger than 10(-4) M cadmium chloride were lethal to human lymphocytes in our experimental conditions. A highly statistically significant increase was observed in the SCE frequency with increasing cadmium chloride concentration (10(-7)-10(-4)) when cadmium was administered at the early S phase, which was 24 h after culture initiation. The increase in SCE frequency was higher when the cultures were terminated at 54 h: compared to termination at 72 h. In order to examine the effects of cadmium administered at the S phase on SCE frequency in different individuals, 10(-5) M concentration was used and the cultures were terminated at 54 h after culture initiation. A 2- to 3-fold increase in the SCE frequency was observed in all six individuals examined. A progressive decrease in the proliferative index was also observed by increasing cadmium chloride concentration. These results demonstrate that the genotoxicity of cadmium chloride may be changed depending on the stage of the cell cycle in human lymphocytes. This may be one of the reasons of contradictory findings in the literature. (C) 1998 Elsevier Science B.V

DNA single-strand breakage in rat lung, liver and kidney after single and combined treatments of nickel and cadmium

Single-strand breaks were observed in rat lung and kidney after acute treatment of animals with CdCl2 (4 mg/kg body weight) injected intraperitoneally and NiCl2 (44.4 mg/kg body weight) injected subcutaneously. In the rat liver, no single-strand breakage was evident with those doses in single and combined metal treatments. The most susceptible tissue in rats to cadmium or nickel chloride treatment was the lung tissue. The single-strand breaks were higher in cadmium treatment than in nickel treatment in the rat lung. Also the response to cadmium treatment was obtained earlier than nickel. Rat kidney was also responsive to cadmium treatment. However, the response, although statistically significant, was much lower than the one obtained in rat lung. The combined treatment, which was done by administrating cadmium prior to nickel administration, reduced the number of single-strand breaks significantly and reversed them to control values in rat lung and kidney. This study confirms that cadmium and nickel create single-strand breaks when administered alone in the rat lung. This effect, which was seen in the single metal treatments, was reduced in the combined treatments. (C) 1997 Elsevier Science B.V

PURIFICATION AND CHARACTERIZATION OF 2 FORMS OF SOLUBLE NADH CYTOCHROME-B5 REDUCTASES FROM HUMAN ERYTHROCYTES

1. Two forms of soluble NADH cytochrome b5 reductase were purified from human erythrocytes. Two distinct fractions both having the NADH cytochrome b5 reductase activity eluted from the second DEAE-cellulose column were further purified by ultrafiltration and 5'-ADP-agarose affinity chromatography