- Laboratory values that will define normal renal and hepatic function, as well as criteria for exclusion of metabolic bone disease are consistent with those established by the University of Michigan Health System (UMHS). Normal clinical values will be used to help assure the health of all subjects in this trial. Potential subjects whose laboratory values fall outside the UMHS normal ranges and are considered clinically significant will be required to have medical clearance from their primary care provider prior to participation. Potential subjects presenting with clinically insignificant laboratory abnormalities will not require medical clearance and will be considered for inclusion in the study