Different virulence of porcine and porcine-like bovine rotavirus strains with genetically nearly identical genomes in piglets and calves.

Direct interspecies transmissions of group A rotaviruses (RVA) have been reported under natural conditions. However, the pathogenicity of RVA has never been directly compared in homologous and heterologous hosts. The bovine RVA/Cow-tc/KOR/K5/2004/G5P[7] strain, which was shown to possess a typical porcine-like genotype constellation similar to that of the G5P[7] prototype RVA/Pig-tc/USA/OSU/1977/G5P9[7] strain, was examined for its pathogenicity and compared with the porcine G5P[7] RVA/Pig-tc/KOR/K71/2006/G5P[7] strain possessing the same genotype constellation. The bovine K5 strain induced diarrhea and histopathological changes in the small intestine of piglets and calves, whereas the porcine K71 strain caused diarrhea and histopathological changes in the small intestine of piglets, but not in calves. Furthermore, the bovine K5 strain showed extra-intestinal tropisms in both piglets and calves, whereas the porcine K71 strain had extra-intestinal tropisms in piglets, but not in calves. Therefore, we performed comparative genomic analysis of the K71 and K5 RVA strains to determine whether specific mutations could be associated with these distinct clinical and pathological phenotypes. Full-length sequencing analyses for the 11 genomic segments for K71 and K5 revealed that these strains were genetically nearly identical to each other. Two nucleotide mutations were found in the 5' untranslated region (UTR) of NSP5 and the 3' UTR of NSP3, and eight amino acid mutations in VP1-VP4 and NSP2. Some of these mutations may be critical molecular determinants for RVA virulence and/or pathogenicity.

Effects of crosslinked dextran in hydroxylpropyl methylcellulose on soft tissue augmentation in rats.

This study compared crosslinked dextrans in hydroxylpropyl methycellulose (DiHMs, pH 5 or 7) with polymethylmethacrylate in bovine collagen (PMMA) and hyaluronic acid (HA) fillers on soft tissue augmentation and safety in rats. HA tended to maintain its size throughout the experimental period but was moveable and friable because of a lack of thick fibroconnective tissue formation. Although, PMMA induced moderately thick fibroconnective tissue formation, its size was decreased markedly from 3-week postimplantation (PI) and became the smallest at 24-month PI. DiHM (pH 7) elicited strong fibrous encapsulation around the filler. Its size decreased slowly but was still considerably maintained at 24-month PI. In contrast, the rate of the DiHM (pH 5) size decrease was slower than that of PMMA, faster DiHM (pH 7), but comparable to HA. Immunohistochemically, types I and III collagens were deposited inside and outside DiHMs (pH 5 and 7). DiHMs (pH 5 and 7), PMMA, and HA showed no adverse reactions. These results suggest that DiHM (pH 7) assures efficacy and safety and is a good candidate for soft tissue augmentation in both humans and animals.