Fluorescent image of normal and stenotic human aortic valves taken using confocal microscopy

Levels of oxidative stress in a normal human aortic valve (left) and in the calcified region of a stenotic aortic valve excised at the time of valve replacement surgery (right). Increased oxidative stress is indicated by the intense red fluorescence, located almost exclusively in the calcified and pericalcific regions of the stenotic aortic valves.