1. Departments of Internal Medicine and
2. Division of Research and Education, Scott & White Hospital and The Texas A&M University System Health Science Center, College of Medicine and
3. Third Department of Internal Medicine, Tohoku University School of Medicine, Aobaku, Sendai, Japan 980-8574; and
4. Division of Gastroenterology, University of Rome, La Sapienza, Rome, Italy 00100
5. Medical Physiology,
6. Central Texas Veterans Health Care System, Temple, Texas 76504;