NO has a wide range of physiologic and pathophysiologic effects on the immune, nervous, cardiovascular, endocrine and other systems.55 It is a lipidand water-soluble radical gas that can react in water with oxygen and its reactive intermediates to form other radicals which contribute to the cytotoxic activity of macrophages.56 NO is synthesized from L-arginine, oxygen and NADPH by NO synthase (NOS