Group 1: Placebo losartan and placebo N-acetylcysteine Group 2: Losartan (25mg/dose) and placebo N-acetylcysteine Group 3: N-acetylcysteine (50 mg/kg/dose) and placebo losartan Recruitment. They will recruit and study 24 (n=8 per group) elderly men and women representative of the ethnic makeup of the United States (see Targeted/Planned Enrollment). The investigators will screen 48 people to achieve a total of 24 completed studies Subjects will be recruited through the Sealy Center on Aging Volunteer Registry at the University of Texas Medical Branch (UTMB). This registry provides a contact point for more than 600 older volunteers. Recruitment coordinators within the Center are trained to telephone screen individuals for past medical history, current health status and medications to determine if they will "fit" into a particular study. Recruitment and study coordinators will then arrange to meet the volunteer at the Clinical Research Center (CRC) to discuss the study and review the consent form. If consented, volunteers are screened and deemed eligible if they meet all inclusion criteria.