Se-Methyl-Seleno-L- Cysteine (MSC) in Treating Healthy Patients

PRIMARY OBJECTIVES: I. To evaluate the toxicity of MSC, given to healthy adult males as a single oral dose. SECONDARY OBJECTIVES: I. To characterize the pharmacokinetics of single oral doses of MSC in healthy adult male volunteers. II. To evaluate the baseline selenium content of toenail clippings in healthy adult males. OUTLINE: This is a multicenter, randomized, placebo controlled, double blind, dose escalation study. Participants are randomized to 1 of 2 arms. Arm I: Participants receive oral placebo on day 1. Arm II: Participants receive oral Se-methyl-seleno-l-cysteine (MSC) on day 1. Cohorts of 5 participants receive escalating doses of MSC until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 5 or 2 of 10 patients experience dose-limiting toxicity. Participants undergo blood, urine, and toenail clipping collection for pharmacokinetic and correlative studies. Samples are analyzed for plasma protein levels of selenium for proteomic and gene expression, molecular fingerprinting by mass spectrometry, and RNA by gene array analysis. After completion of study treatment, participants are followed at 7-14 days and at 30 days.