Quantitative ultrastructural analysis of perifibrous lipid and its association with elastin in nonatherosclerotic human aorta.

Age-related changes in human macular Bruch's membrane as seen by quick-freeze/deep-etch

“…This may be analogous to the early pathogenesis of an arteriosclerosis that demonstrates LDL depositions in the elastic lamina of the vascular intima (Kramsch and Hollander, 1973;Guyton et al, 1985;Bocan et al, 1988;Podet et al, 1991;Bobryshev and Lord, 1999;Wang et al, 2001). It has been postulated that LDLs can interact with elastin fibrils via hydrophobic amino acids (Bobryshev and Lord, 1999) or by interactions between the oxidized LDL and calcium ion binding elastin fibrils (Wang et al, 2001).…”

Ultrastructural Localization of Secretory Type II Phospholipase A 2 in Atherosclerotic and Nonatherosclerotic Regions of Human Arteries

“…40 Earlier EM and EM-immunogold labeling studies by other groups have reported the presence of apoB lipoproteins in the ECM, colocalized with chondroitin sulfate proteoglycans and along collagen fibers in the arterial intima. [41][42][43][44] This entrapment of apoB lipoproteins in the ECM may provide the opportunity for further structural, hydrolytic, and oxidative modifications of the lipoproteins, with consequences for the cells in the arterial wall. 45 There is indirect evidence that one modification that occurs rapidly, once apoB-100 lipoproteins are in the arterial intima, is the hydrolysis of PC by PLA 2 -like activity [46][47][48] Lyso-P, a product of hydrolysis of PC by PLA 2 , is found in atherosclerotic lesions, and the PC to lyso-PC ratio in these lesions is lower than that in comparable control tissue.…”

Metabolism of LDL in mast cells recovering from degranulation. Description of a novel intracellular pathway leading to proteolytic modification of the lipoprotein.

“…To preserve the lipid structures, the cell pellets were postfixed with successive treatments of osmium tetroxide, thiocarbohydrazine, and osmium tetroxide as described previously. 31 The samples were dehydrated and embedded in LX-112 embedding medium (Ladd Research Industries). Ultramicrotome sections were stained with uranyl acetate and lead citrate and viewed with a JEOL JEM-100CX transmission electron microscope at the Department of Electron Microscopy, University of Helsinki.…”

“…These large LDL particles were identical in appearance to those formed when LDL was incubated with isolated granule remnants ( Figure 4C). When exposed to successive treatments with osmium tetroxide, thiocarbohydrazine, and osmium tetroxide, 31 these modified LDL particles were encircled by the black rims typical of lipid droplets. The above results demonstrate that the LDL taken up from the extracellular space by the granule remnants is subsequently converted to large lipid droplets within the granule compartment of the stimulated mast cells.…”