Browsing by Author "Rao, SB"

Now showing 1 - 3 of 3
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    Sterilization of chitosan: Implications
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 1995)
    Chitosan, a biopolysaccharide having structural characteristics similar to glycosaminoglycans, seems to be an ideal non-toxic and bioabsorbable biopolymer. This study highlights the effects of some physical and chemical methods of sterilization on chitosan films, in retaining the original tensile strength besides the efficacy of sterility and degree of hemolysis of the finished films.
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    Structural studies on bovine bioprosthetic tissues and their in vivo calcification: Prevention via drug delivery
    (BIOMATERIALS, 1996)
    Cardiovascular calcification, the formation of calcium phosphate deposits in cardiovascular tissue, is a common end-stage phenomenon affecting a wide variety of bioprostheses. To study the process of calcification in tissue prosthetics, glutaraldehyde-treated bovine pericardium, dura mater and fascialata were implanted subcutaneously in rats and retrieved 21 days later and thereby morphological findings were correlated with biochemically determined levels of calcium. Transmission electron microscopy showed that calcification primarily involved the surface of collagen fibrils and the interfibrillar spaces. The deposition of calcium was higher with dura and fascia prostheses compared to pericardium. However, the release of Fe3+ ions from chitosan matrix had substantially inhibited the deposits of calcium in all implanted tissues. It seems that the structural and anatomical features of the tissue is one of the important factors for tissue-associated calcification. It is also confirmed that glutaraldehyde-preserved pericardium is the most suitable material for the development of cardiac prosthesis, with an appropriate drug combination therapy for prevention of pathological calcification.
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    Use of chitosan as a biomaterial: Studies on its safety and hemostatic potential
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 1997)
    Chitosan, a mucopolysaccharide of marine origin, was studied for its safety and hemostatic potential. Its surface was treated with glutaraldehyde, carbodiimide, and plasma glow discharge to elicit effects of enzyme degradation. Of the seven enzymes used, leucine amino peptidase caused maximum degradation. Autoclaving appeared to be an ideal sterilizing method as it caused least decrease in tensile strength and effected a negligible rate of hemolysis. Sterilizing with glutaraldehyde with a physiologic pH retained the maximum tensile strength of chitosan. In vivo toxicity tests indicated that it is nontoxic, and the sterilized films were free of pyrogen. Coagulation and hemagglutination tests showed that the hemostatic mechanism of chitosan seems to be independent of the classical coagulation cascade and appears to be an interaction between the cell membrane of erythrocytes and chitosan. (C) 1997 John Wiley & Sons, Inc.