Optimization of chemotherapy delivery for immunodeficient mice. (A) Weights of representative mice exposed to chemotherapy (A, cytarabine; D, doxorubicin; DA, combined cytarabine and doxorubicin; IP, intraperitoneal delivery; IV, intravenous delivery). Cytarabine was given on days 1 to 5 and doxorubicin on days 1 to 3 only. (B) Whole livers were isolated from mice 28 days after initiation of drug injections. (C) Survival of mice was monitored for 30 days after exposure to different doses of cytarabine and doxorubicin. DA indicates 1.5 mg/kg doxorubicin and 50 mg/kg cytarabine. DA 2× is 3.0 mg/kg doxorubicin and 100 mg/kg cytarabine. The first number of 5+3 or 3+2 is the number of daily doses of cytarabine, and the second indicates the same for doxorubicin. A consistent volume was injected at each dose (10 microliters per gram of body weight) by preparing appropriate stock solutions. (D) Survival of mice receiving the optimized maximum-tolerated doses of D+A chemotherapy following the indicated sublethal doses of whole-body irradiation.