2.2 Animals and General Procedures

All procedures and protocols used in the described in vivo studies were reviewed and approved by the Institutional Animal Care and Use Committee of Lawrence Berkeley National Laboratory and were performed in AAALAC accredited facilities. The animals used were young adult (86 ± 6 days old for delayed treatment experiment and 90 ± 3 days old for prophylactic treatment experiment) female (30.7 ± 4.0 g for delayed treatment experiment and 30.8 ± 1.6 g for prophylactic treatment experiment) Swiss-Webster mice (Simonsen Laboratories, Gilroy, CA, USA). Gross body and tissue compositions, plasma, extracellular fluid, and red cell volumes of the whole body, major tissues and organs of these mice (intact or bled 25 to 40% of their total blood volume) have been determined previously [23]. Mice were kept under a 12-hour light cycle with controlled temperature (18–22°C) and relative humidity (30–70%), and were given water and food ad libitum. Each group of mice was housed together in a plastic stock cage lined with a 0.5 cm layer of highly absorbent low-ash pelleted cellulose bedding (ALPHA-dri®) for separation of urine and feces. Intravenous (iv) injections into a warmed lateral tail vein, intraperitoneal (ip) injections, oral administrations (po, through gastric intubation) and euthanasia were performed under isoflurane anesthesia. Treatment dose volumes were adjusted based on the weight of the mouse, with a 0.5 mL volume corresponding to a 35 g mouse. To probe the effect of delayed treatment, groups of five mice were injected iv with a single dose of ²³⁸Pu-citrate, and ligand or control saline solutions were administered ip once at the following post-contamination treatment times: 1 h, 5 h, 16 h, 24 h, 3 d, 7 d. Excreta were collected daily for 7 days. Animals were euthanized 7 days after treatment. To probe the effect of prophylactic treatment, groups of five mice were first administered ligand or control saline solutions ip or po once at the following pre-contamination treatment times: −1 h, −6 h, −16 h, −24 h, −30 h, −40 h, −48 h. Mice were then injected iv with a single dose of ²³⁸Pu-citrate and excreta were collected daily for 3 days. Animals were euthanized 3 days (72 h) after contamination. Mice were euthanized by cervical dislocation over their respective cage to collect the urine expelled at death, and immediately wrapped in plastic and frozen for later dissection.