1. Department of Therapeutic Radiology-Radiation Oncology, University of Minnesota, Minneapolis, MN 55455, USA.
2. Centralized Immunoconjugate Reference Laboratory of the Childrens Cancer Group, University of Minnesota, Minneapolis, MN 55455, USA.
3. Pharmaceutical Department, St. Jude Children's Research Hospital, Memphis, TN 38101, USA.
4. Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
5. Signal Transduction Laboratory, Department of Molecular Biology, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543, USA.