1. INRA Laboratory 54189, Department of Biochemistry, Ecole Nationale Veterinaire de Lyon, 69752 Charbonnieres Cedex, France
2. Hazleton-IFT, BP No. 118, 69210 St Germain sur l'Arbresle, France
3. Pathology and Toxicology Research Service, Upjohn Company, Kalamazoo, Michigan 49001, USA