It is challenging to diagnose metastatic tumors whose cellular morphology is different from the primary. We characterized canine primary pulmonary adenocarcinoma (PAC) and its xenografted tumors by histological and immunohistochemical analyses for critical diagnostic and cancer stem cell (CSC) markers. To generate a tumor xenograft model, we subsequently transplanted the tissue pieces from the PAC into athymic nude mice. Immunohistochemical examination was performed for diagnostic (TTF-1, Napsin A, and SP-A) and CSC markers (CD44 and CD133). The use of CSC markers together with diagnostic markers can improve the detection and diagnosis of canine primary and metastatic adenocarcinomas.

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Background: Escherichia coli infections have been causing post-weaning diarrhea (PWD) and edema disease (ED) for many years in the porcine industry. In animals, it is classified into pathotypes and serotypes, according to virulence factors. Serotyping is performed for O, K, H, and F antigens, which are important for discriminating pathogenicity and epidemiology. Furthermore, E. coli strains that produce F18 fimbriae are major sources of ED and PWD associated with Shiga-toxin producing E. coli (STEC) expressing F18ab, and enterotoxigenic E. coli (ETEC) expressing F18ac, respectively. Aim: To investigate the pathogenicity potential and infection characteristics of an experimental infection and confirm the pathological features of the Korean STEC/ETEC strains F18ab and F18ac in piglets. Methods: Three-week-old pigs were randomized into three experimental groups: infected G1 (F18ab), infected G2 (F18ac), and G3 (control). General health status was monitored daily, and pathological changes were evaluated. Results: Diarrhea occurred in all infected piglets. Pathological changes were only observed in the small intestine and regional lymph nodes. In G1, mucosal necrosis, inflammatory cell infiltration with hemorrhagic lesions, and apoptotic cell death in the tunica media of arterioles in the small intestine were observed. In contrast, the mucosa and epithelium appeared almost intact, with no abnormal vessel lesions in G2. Conclusions: Both strains which isolated from pigs in Korea could be infected and did not spread from the alimentary tract to other organs. The pathological features were quite different among the F18 subtypes. The F18ab strain was more virulent than F18ac, and virulence characteristics of the F18ac strain were more similar to ETEC than to STEC.

Intratympanic administration for the delivery of steroids has been extensively studied but limited because of low permeability of the drug through the row window membrane. Here, to effectively deliver poorly soluble triamcinolone acetonide (TA), microemulsions (ME) were prepared from Capmul MCM (oil), Cremophor RH40 (surfactant), and tetraglycol (cosurfactant) based on solubility studies, emulsifying ability test, and pseudoternary phase diagrams. Microemulsion gel (MEG) was prepared by mixing TA-ME with a poloxamer hydrogel base. The physicochemical properties of ME and MEG formulations were characterized, and the toxicity and oto-protective effectiveness were evaluated in vitro and in vivo. The ME-3 formulation showed a small droplet size (16.5 ± 0.2 nm), narrow PDI (0.067 ± 0.041), and enhanced TA solubility (2619.7 ± 57.6 μg/g). The optimized MEG demonstrated temperature-dependent gelation with a gelation time of 208 ± 10 sec at 37 °C. Slow degradation of the gel matrix sustained release of TA from MEG compared to the ME formulation. Both TA-ME and TA-MEG were found to be nontoxic to NIH3T3 cells at the test concentrations (0 to 5 µg/mL), and biocompatible after intratympanic administration to mice. The incorporation of ME into thermosensitive hydrogels prolonged retention of TA at the site of administration until 6 days. As a consequence, the enhanced drug absorption into the cochlea in TA-MEG group (approximately 2 times higher than other groups) protected hair cells, spiral ganglion neurons, and stria vascular cells from cisplatin-induced damage. Therefore, this injectable TA-loaded MEG is an effective and safe vehicle for the sustained delivery of triamcinolone acetonide into the inner ear.