1. Institut für Pharmakologie, Toxikologie und Pharmazie
2. Medizinische Kleintierklinik; Ludwig-Maximilians-Universität München; Munich Germany
3. Department of Clinical Sciences; College of Veterinary Medicine; North Carolina State University; Raleigh NC 27606 USA
4. Department of Pathology; School of Veterinary Medicine; Tuskegee University; Tuskegee AL 36088 USA