Impairment of liver function upon treatment with 4D5MOCB-ETA. Impairment of liver function upon treatment with 4D5MOCB-ETA. C57BL/6 mice were treated every other day with escalating doses of 4D5MOCB-ETA. Two groups received 5-μg (250 μg·kg−1) or 10-μg (500 μg·kg−1) doses for three cycles, whereas another group was treated twice with 20 μg (1000 μg·kg−1). Twenty-four h after the last challenge, the activities of plasma transaminases were determined and compared with mice treated with PBS (0 μg·kg−1). The transaminase activities of mice treated with a single lethal dose of wild-type ETA (85 μg·kg−1), as described by Schümann et al. (47) , are also shown. Data are expressed as the mean ± SD (n = 3). Claudio Di Paolo et al. Clin Cancer Res 2003;9:2837-2848 ©2003 by American Association for Cancer Research