Fig. 2.

In vitro effect of As and Cd on the apoptosis and necrosis of normal human MNC. (a, b) Kinetics analysis of the effect of As and Cd on the apoptosis of MNC. Cells were exposed to NaAsO₂, CdCl₂ or culture medium alone for the indicated periods of time and then the percentage of cells undergoing apoptosis was determined by propidium iodide staining, as described in Material and methods. Results correspond to one representative experiment out of three performed. (a) ▴, As (15 μm); ▪, Cd (100 μm); •, medium alone. (b) ▿, As (5·0 μm); ▾, As (2·5 μm); ○, As (1·0 μm); •, medium alone. (c, d) Effect of As and Cd on MNC viability. Peripheral blood MNC were incubated in the presence of the indicated concentrations of Cd (c) and As (d) for 48 h and then the number of viable and necrotic cells was determined by trypan blue staining and direct microscope counting. In cell cultures run in parallel, the percentage of apoptotic cells was determined as in (a). Results correspond to the arithmetic mean and s.d. of five independent experiments. (c, d) •, Viable cells; □, apoptotic cells; ▵, necrotic cells.