1. Department of Urologic Surgery, University of Minnesota Medical School, Minneapolis, MN 55455.
2. Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555-1019.
3. Department of Microbiology and Immunology, Infectious Disease and Toxicology Optical Imaging Center, University of Texas Medical Branch, Galveston, TX 77555-1019.