1. Presence of major illnesses: renal (serum creatinine greater than 1.6), hepatic (AST/ALT greater than 3 times upper limit of normal range used in Clinical Center assays), gastrointestinal, most endocrinologic (e.g. Cushing syndrome, hyper- or hyothyroidism), hematological problems or pulmonary disorders (other than asthma not requiring continuous medication or sleep-apnea related disorders);