Avidin [Biotin]

Oxidized form of avidin, named AvidinOX, provides stable fixation of biotinylated molecules in tissues thus representing a breakthrough in topical treatment of cancer. AvidinOX proved to be a stable receptor for radiolabeled biotin, biotinylated antibodies and cells. In order to expand applicability of the AvidinOX-based delivery platform, in the present study we investigated the possibility to hold biotinylated chemotherapeutics in AvidinOX-treated sites. A novel biotinylated gimatecan-derived camptothecin, coded ST8161AA1, was injected at suboptimal doses into human tumors xenografted in mice alone or pre-complexed to AvidinOX. Significantly higher growth inhibition was observed when the drug was anchored to AvidinOX suggesting the potential utility of this delivery modality for the local treatment of inoperable tumors.

This study aimed to examine the structure of the buzzard's Buteo buteo) small intestine and liver, and the localization of catalase in those organs. Crossman's modified triple stain and Periodic Acid Schiff (PAS) stain were applied to the samples for histological examination. To detect catalase localization in the tissues, the avidin-biotin-peroxidase complex (ABC) technique was used. It was observed that the general histological structure of the buzzard's small intestine and liver was similar to that of other avian species. Catalase immunoreactivity in the lamina propria and subrnucosa in the small intestine were also observed, as well as catalase irnmunoreactivity in the hepatocyte cytoplasm in the liver. Some areas in the small intestine and liver had catalase immunoreactivity, which means that an antioxidant defence occurs in those areas.