1. Cogenics, A Division of Clinical Data, Morrisville, North Carolina 27560, USA
2. Environmental Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
3. National Center for Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
4. Integrated Laboratory Systems, Inc., Research Triangle Park, North Carolina 27709, USA
5. Experimental Pathology Laboratories, Inc., Research Triangle Park, NC 27709,USA