1. Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center, ND8.136B, Dallas, Texas 75390-9041, United States
2. Department of Chemistry, McGill University, Montreal, Quebec H3A 2K6, Canada
3. Isis Pharmaceuticals, 1896 Rutherford Road, Carlsbad, California 92008, United States
4. SIGMA Custom Products, Genopole Campus 1, 5 Rue Desbruères, 91030 Evry Cedex, France
5. Glen Research Corporation, 22825 Davis Drive, Sterling, Virginia 20164, United States
6. Department of Bioorganic Chemistry, Uppsala University, Biomedical Center, Box 581, S-751 23 Uppsala, Sweden