Anionic sites in articular cartilage revealed by polyethyleneimine staining

High-Throughput Turbidimetric Screening for Heparin-Neutralizing Agents and Low-Molecular-Weight Heparin Mimetics

“…PEI is reported to have GAG-binding property, and utilized as an HS proteoglycan-mediated DNA transfection agent 15) and a GAG stain for histology. 16) The heparin-inhibiting property of compound 1 was similar to that of PEI (Fig. 7).…”

“…We thus compared the heparin-neutralizing activity of 1 with that of PEI, which is a polyamine known to interact with heparin/HS proteoglycans, 15,16) by the collagen fibril formation assay (Fig. 7).…”

Voxel-based reproducibility of T2 relaxation time in patellar cartilage at 1.5 T with a new validated 3D rigid registration algorithm

“…The regionally differing orientations of the collagen fibers in the articular cartilage thus lead to increasing T2 from the bone-cartilage interface (BCI) to the articular surface (AS) [3][4][5][6]10,12,14]. In the presence of degenerative changes in the collagen-proteoglycan matrix, T2 relaxation time is markedly increased [15][16][17], probably as a consequence of the lower water confinement in damaged cartilage [15,18].…”

Methodology

“…The loss of anionic molecules during fixation and decalcification can largely be avoided by the cationic-dye stabilization method, which relies on addition to the fixative of cationic substances such as the cationic dyes alcian blue, acridine orange, cupromeronic blue, polyethyleneimine, ruthenium hexammine trichloride, ruthenium red, safranin O, or toluidine blue O (Shepard and Mitchell 1976a, b;Takagi 1990;Shepard 1992;Engfeldt et al 1994;Király et al 1996;Ueda et al 1997Ueda et al , 2001Leng et al 1998). The cationic-dye method gives an ultrastructural pattern comparable with that which can be obtained using high pressure freezing, freeze substitution and low temperature embedding (Engfeldt et al 1994).…”