The use of glutaraldehyde (GTA) for cross-linking biological tissue implants has a number of undesirable side effects, including cytotoxicity and induction of calcification. In an attempt to find an improved cross-linking agent for tissue implants, we have evaluated a number of cross-linking procedures shown previously to be effective with pure collagen or collagenous substrates, including GTA, succinic anhydride, cyanamide, 1-ethyl-3-(dimethylaminopropyl)carbodi-imide, dimethyl suberimidate, ascorbate-copper, glucose-lysine and acyl azide treatments. Apart from GTA, only acyl azide treatment significantly cross-linked human dermis, the degree of cross-linking being better than that seen after treatment of dermis with 1 mM GTA. Acyl azide treatment of thicker vascular tissue (porcine aorta) also resulted in a significantly cross-linked tissue. Preliminary cytotoxicity studies suggested that acyl azide treatment was not toxic, and, therefore, coupled with its cross-linking ability, this treatment is worthy of further investigation and may prove to be an alternative to GTA for the treatment of bioprostheses.
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Chem Asian J
December 2024
National Institute of Pharmaceutical Education and Research, Medicinal Chemistry, Sector 67, 160062, S. A. S. Nagar, INDIA.
Ru(II)-Catalyzed "On Water" direct aryl C(sp2)-H amidation of 2-arylbenzo[d]-thiazole/oxazole with acyl azide is reported under silver-free condition. Deuterium scrambling experiments suggested reversible C-H activation catalyzed by active cationic ruthenium species. The organic solvents such as DCE, DMF, DMSO, MeCN, dioxane, and PhMe were not conducive for the C-H amidation except for PhCl in which case, however, inferior yield (31%) was obtained.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz1, 45470, Mülheim an der Ruhr, Germany.
J Org Chem
September 2024
Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
,-Dimethylformamide was reacted with hexamethyldisilazane to generate an ,-dimethylformimidamide intermediate; thereafter, a reaction with acetophenones/β-diketones was induced to form enaminones. The one-pot synthetic protocol described in this paper can be applied to synthesize 1,4-disubstituted 1,2,3-triazoles and 1,4,5-trisubstituted 1,2,3-triazoles, in which organic azides are used as substrates under optimized conditions. Furthermore, this protocol uses readily available materials, is nearly free of solvent, can be applied to gram-scale operations, and leads to the formation of structurally diverse products with favorable yields.
View Article and Find Full Text PDFJ Am Chem Soc
July 2024
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Lihu Avenue 1800, Wuxi, Jiangsu 214122, P.R. China.
bacteria are becoming increasingly resistant against multiple antibiotics. Therefore, the development of vaccines to prevent infections with these bacteria is an urgent medical need. While the immunological activity of lipopolysaccharide O-antigens in is well-known, the specific protective epitopes remain unidentified.
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