Collagen grafting

Furthermore, soluble collagen grafted with polyacrylamide formed fibrils on heating to 37 °C at neutral pH, but unlike the native collagen, these fibrils did not redissolve on cooling to 2°C (8). These results indicate that the redispersion property of soluble collagen is impaired, probably by attachment of the polyacrylamide side chains to the collagen molecule. 

Figure 7.76 Development of human osteoblasts on the surfaces of as-HVOF-sprayed (a), alkali treated (b) and collagen grafted (c) HAp/Ti02 coatings. Fluorescence staining shows that in live cells the non-fluorescent calcein-AM is converted to a...

Tong, X.J., Hirai, K., Shimada, H., Mizutani, Y., Izumi, T., Toda, N., Yu, R, 1994. Sciatic nerve regeneration navigated by laminin-fibronectin double coated biodegradable collagen grafts in rats. Brain Res. 663, 155-162. 

Huynh, T. et al., Remodehng of an acellular collagen graft into a physiologically responsive neovessel. Nat Biotechnol, 1999.17(11) 1083-86. 

Figure 1. Kinetics of skin wound contraction in the presence of polymeric grafts which undergo enzymatic degradation at two different rates, R = 17 enzyme units (e.u.) and R = 231 e.u. The variation in R was achieved by controlling the duration of cross-linking of the collagen-graft-glycosaminoglycan in aqueous glutaraldehyde.

Hydroxyapatite constitutes -65% of human bone by weight. There is another 18% collagen fiber which makes the bone flexible and more durable. Then, there is -10% genetic tissue (mostly living bone cells). This tissue carries the genetic code of the person or animal and unless it is in a denatured form, which also kills the bone, it is likely to be rejected in the body as a bone graft. Therefore, it is impossible to successfully implant living bone even from closely related donors. The remainder of bone is composed of capillaries, nerves, and so on. 

Figure 26. Reconstruction of the tunica intima on the inner surface of a clinically used polyethylene terephtalate vascular prosthesis. A non-modified inner surface of the prosthesis, B immobilization of defined assemblies of protein molecules (e.g., collagenfiarninin or collagen+fibrin) on the inner surface of the graft, C immunofluorescence of von Willebrand factor, a marker of the identity a differentiation of vascular endothelial cells, in human saphenous vein endothelial cells in cultures on the inner surface of a prosthesis coated with collagen and larninin, D detail of a layer of endothelial cells growing on a layer of collagen and fibrin. Note well developed talin-containing focal adhesion plaques. A, B conventional optical microscope, C, D confocal microscope Leica DM 2500 [30,31].

When collagen-GAG matrices which can significantly delay the onset of wound contraction are seeded with a minimum density of easily separable skin cells (basal cells) from the same animal, and the cell-seeded matrices are then grafted, wound healing is affected in an even more profound way In this case,... 

Fig. 9. Variation of half-life of skin wound with the average pore diameter of collagen-GAG matrices used as grafts for full-thickness skin wounds in the guinea pig. The vertical broken lines at about 20 and 120 pm mark the limits of matrix activity. Outside these approximate limits the wound half-life rapidly drops to the level of the ungrafted wound. The horizontal scale is logarithmic [79]...

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