Use of Aspirin to Prevent Thrombosis

Because aspirin binds irreversibly with cyclooxygenase it inhibits the enzyme in platelets for their entire lifespan, since platelets are unable to 

Reactive Oxygen Species, Oxygen-Free Radicals, Lipid Peroxides, and Their Interaction with Arachidonic Acid Metabolism 

In many of the pathological conditions of the brain in which eicosanoid production is increased, it has been found or speculated that there is production of oxygen-free radicals, and that lipid peroxidation occurs. The chemistry of these species is considered briefly, since their effects on brain structure and function may be additive to those of eicosanoids. Moreover both interact with the arachidonic acid cascade and can modify eicosanoid production. 

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