New increase in superoxide production in neurons/glia and blood vessel cells was found on D30, accompanied with increased [H.sub.2][O.sub.2] production in the internal elastic membrane. Also, the blue autofluorescence of the internal elastic membrane was the most intensive in the whole development.
It has also shown that there is a correlation between the absence of elastic fibers and the presence of discontinuities in the internal elastic membrane. This enhances the development of intimal hyperplasia and graft occlusion (van Son et al, 2006).
The internal elastic membrane responsible for the thinning of the artery wall is either reduced in size or absent causing the media to retract to the junction of the aneurysm neck with the parent blood vessel.
The subendothelial layer of the intima in arteries and arterioles contains a sheetlike layer or lamella of fenestrated elastic material called the internal elastic membrane. Fenestrations enable substances to diffuse readily through the layer and reach cells deep within the wall of the vessel.
Intramural hematoma is defined as an accumulation of blood within the medial space displacing the internal elastic membrane inward and the external elastic membrane outward, with or without identifiable entry or exit points .