A Basic Research of Small Caliber Vascular Xenografts with Antithrombogenicity

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[Immunogenicity] To evaluate the effects of polyepoxy compounds (PC) on the immunogenicity of biomaterials, DDY mice were immunized with homogenates of glutaraldehyde(GA), glycerol polyglycidyl ether(GPE), and untreated dog (donor) arteries. Using their sera, donor peripheral lymphocytes were stained with FITC labeled anti-mouse IgG antibodies and analyzed with cytofluorometry. This experiment revealed that GPE reduced the immunogenicity of arteries to the same level as GA. To investigate the relationship between reaction time and immunogenicity, dog arteries were cross-linked with GPE for 1, 12, and 48 hourg. Using these treated arteries, the immunogenicity was detected. This experiment indicated thatcross-linking with GPE for 48 hours seemed to be the best treatment.[Mechanical properties] To evaluate the relationship between the reaction time and mechanical properties, dog arteries treated with GPE forl, 12, and 48 hours. A stress-strain (S-S) curve of each sample was recorded. From … More the S-S curve, the maximum stressforce of each sample was calculated and flexibility was compared using finite deformation theory. The results of this experiment showed that GPE made the arteries stronger and harder in proportion of reaction time. Bovine arteries were treated with GPE and GA for 48 hours to compare their effects on the mechanical properties.This experiment revealed that arteries treated with GPE for 48 hours were about 3 times as flexible as those treated with GA for 48 hours, despite a similar strength.[Antithrombogenicity] Protanine sulfate was used to increase heparin binding covalently to arteries with PC. Protamine sulfate solution was poured into dog arteries. Then the arteries were dipped into a PC solution to cross-link the protanine sulfate within the matrix of the arteries. Finally, these arteries were dipped into heparin solution. By this method, heparin was ionically bound to the inner side of the arteries. 80 dog arteries treated with this method were implanted to 40 dogs and 77 of 80 grafts remained patent. However, It takes more than 10 hours to heparinize the arteries. Therefore, we introduced a new method using GA instead of PC. Since it takes only 15 minutes to heparinaze the arteries using this method, we applied this new method to heparinize arteries after TEA clinically and met good results. Less