The current proposal, will elucidate the role of oxidant stress (OS) on arterial function as measured by flow mediated vasodilation. In addition, the investigators will address the hypothesis, that a pro-oxidant might have different degrees of effects on different biological targets, by performing quantitative assessment of the effects of OS on lipids, proteins and DNA.

Inclusion Criteria:

• Chronic smokers (of between 4 and 20 years duration) and non-smokers will be recruited to the GCRC. Smokers will be allocated to a "light" group, smoking 4-10 cigarettes per day and a "heavy" smoking group who smoke 11-20 cigarettes per day.
• Non-smokers will be defined as those with a life time consumption of no more than 20 cigarettes, do not live or work in a smoky atmosphere.
• All individuals will have a normal history and clinical examination, including a normal EKG, urinalysis and serum chemistry, haemogram and negative urinary pregnancy test.

Exclusion Criteria:

• previously suffered an acute major cardiovascular event
• those with a chronic disease
• those taking chronic medication
• those with a history of alcoholism or substance abuse
• Ex-smokers
• Subjects, who have less than or equal to 60% platelet aggregation in response to arachidonic acid

Chronic smokers (of between 4 and 20 years duration) and non-smokers will be recruited. Smokers will be allocated to a "light" group, smoking 4-10 cigarettes per day and a "heavy" smoking group who smoke 11-20 cigarettes per day. Non-smokers will be defined as those with a life time consumption of no more than 20 cigarettes, do not live or work in a smoky atmosphere. All individuals will have a normal history and clinical examination, including a normal EKG, urinalysis and serum chemistry, haemogram and negative urinary pregnancy test.