Nitrite Infusion Studies

Exclusion Criteria

• •Subjects with a history or evidence of present or past hypertension (blood pressure greater than 140/90 mmHg), hypercholesterolemia (LDL cholesterol greater than 160 mg/dL), or diabetes mellitus (fasting blood glucose greater than 126 mg/dL)
• •Subjects who have a history of smoking within two years
• •Subjects who have a history of cardiovascular disease, peripheral vascular disease, coagulopathy, or any other disease predisposing to vasculitis or Raynaud's phenomenon.
• •Individuals with a future cardiovascular risk greater than 1 % in the next 10 years will be excluded from the study. Risk will be calculated using the Framingham risk calculator published on the web site: http://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=prof.
• •Subjects with red blood cell G6PD deficiency (levels below the lower limits of normal).
• •Subjects with known cytochrome B5 deficiency will not participate in this study.
• •Subjects with a history of reaction to a medication or other substance characterized by dyspnea and cyanosis will not participate in this study.
• •Subjects with a baseline methemoglobin level greater than 1.9% will not receive nitrite infusions.
• •Lactating females will not participate since nitrite crosses into breast milk and could cause methemoglobinemia in the infant.
• •No volunteer subject will be allowed to take any medication (oral contraceptive agents are allowed), vitamin supplements that contain arginine, herbal preparations, nutriceuticals or other "alternative therapies" for at least one month prior to study and will not be allowed to take aspirin for one week prior to study
• •Subjects with a blood pressure of less than 90/60 mmHg or a MAP (mean arterial blood pressure) of less than 70 on the study day will be excluded from the protocol.
• •Due to exposure of high doses of ascorbic acid in this protocol calcium oxalate stone formers, patients on dialysis or with serious kidney disease, and patients with hemochromatosis and other iron overload diseases will be excluded.