The antimicrobial effects of silver (Ag) ion or salts are well known, but the effects of Ag nanoparticles on microorganisms and antimicrobial mechanism have not been revealed clearly. Stable Ag nanoparticles were prepared and their shape and size distribution characterized by particle characterizer and transmission electron microscopic study. The antimicrobial activity of Ag nanoparticles was investigated against yeast, Escherichia coli, and Staphylococcus aureus. In these tests, Muller Hinton agar plates were used and Ag nanoparticles of various concentrations were supplemented in liquid systems. As results, yeast and E. coli were inhibited at the low concentration of Ag nanoparticles, whereas the growth-inhibitory effects on S. aureus were mild. The free-radical generation effect of Ag nanoparticles on microbial growth inhibition was investigated by electron spin resonance spectroscopy. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.

A 2-year-old intact female Golden Retriever presented due to rapidly progressing depression, ascites, dysuria, abdominal pain, and severe vaginal bleeding. At necropsy, the retroperitoneal space was expanded by multiple coalescing neoplastic nodules and the uterine wall was thickened with poorly defined neoplastic infiltrates. The urinary bladder was markedly thickened due to botryoid nodules exhibiting exophytic growth into the lumen. Metastases to lung, liver, kidney, and abdominal and thoracic lymph nodes were also noted. Microscopically, the genital tract and retroperitoneal masses were consistent with the alveolar subtype of rhabdomysarcoma, while the urinary bladder mass had characteristics of the embryonal subtype. Immunohistochemically, the neoplastic cells in all these tissue sites were intensely positive for desmin, sacromeric actin, and vimentin, while they were uniformly negative for cytokeratin and smooth muscle actin. Phosphotungstic acid hematoxylin stain revealed cross-striations in the cytoplasm of scattered neoplastic cells. Based on the gross findings, histopathology, and immunohistochemistry, genitourinary rhabdomyosarcoma with multisystemic metastases was made.

Blood, saliva, and nail samples were collected from 54 dogs and 151 cats and analyzed for the presence of Bartonella henselae with a novel nested polymerase chain reaction (PCR) method. Bartonella (B.) henselae was detected in feral cat blood (41.8%), saliva (44.1%), and nail (42.7%) samples. B. henselae was also detected in pet cat blood (33.3%), saliva (43.5%), and nail (29.5%) samples and in pet dog blood (16.6%), saliva (18.5%), and nail (29.6%) samples. Nine samples were infected with B. clarridgeiae and 2 were co-infected with B. henselae and B. clarridgeiae of blood samples of dogs. This report is the first to investigate the prevalence of B. henselae and B. clarridgeiae in dogs and cats in Korea, and suggests that dogs and cats may serve as potential Bartonella reservoirs.

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