1. VA Northern California Health Care System, Mather, CA 95655, USA
2. Department of Surgical & Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
3. Department of Urological Surgery, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
4. Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
5. Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA