- Clinically significant laboratory screening test (LST) results on hematology, chemistry, or urine analysis as defined by the FDA Neuropharmacology Division guidelines. Elevation of liver enzymes (SGOT), serum glutamic pyruvic transaminase (SGPT), blood urea nitrogen (BUN), or lactate dehydrogenase (LDH) — up to ×4 above the normal range — will be allowed unless there is evidence of hepatocellular disease or failure. In addition, we will test for hematocrit as more than 300 ml of blood will be taken during study 1. Hematocrit levels must be > 41% for males and > 38% for females.