Profiles of concentrations of arsenic species in PB plasma collected during the remission induction therapy. Blood samples were collected before the treatment start (day -1), and 3, 7, 10, 14, 17, 21, 28, 42, 56 days after the start of administration. The concentrations of arsenic species in plasma were determined with HPLC/ICP-MS as described in "Patient and Methods." A merged representative chromatogram obtained from the analyses of a plasma sample collected on day 14 and the same plasma sample spiked with As(V), As(III), MA(V), DMA(V), and AB is shown in Figure 3(A). The signal peaks are as follows: As(V) (1), As(III) (2), MA(V) (3), DMA(V) (4), and AB (5). The concentrations of arsenic species calculated from these chromatograms are shown in Figure 3(B). (●): As(V); (■): As(III); (▲): MA(V); (♦): DMA(V); (O): AB.