Fig. 1.

DNA damage in AC16 cells exposed to 50 Hz MF. Levels of DNA damage were evaluated by the alkaline comet assay following 1 h continuous (A–D) or 75 min intermittent (E–H) exposure, expressed as tail DNA %, tail length, tail moment and comet length. Negative control (control) represents unstressed cells kept under normal culture conditions. The positive control (positive) used negative control cells exposed to ice-cold 2 µM hydrogen peroxide for 5 min. Each bar shows the mean±s.e.m. of three independent experiments. A minimum of 50 cells were collected from each replica of a sample, using the mean values of the medians of the two replicas for comparison (**P<0.01 versus control). Because the CASPLab program was set to measuring the tail length with an initial value of 3 μm and a minimum increment of 1 μm. The non-normal distribution of comet made the median of several groups 3 μm.