The microbial ecology in mastitis involves the interactions between bacteria and the mammary gland environment. Poor mastitis control, for which understanding these microbial relationships is crucial, increases the risk of mastitis and co-infections. The aim of this study was to determine the pathogenesis and bacterial ecology of murine mammary glands following intramammary infection (IMI) with S. aureus (AU), S. agalactiae (SA), and four isolates of selected non-aureus staphylococci (NAS), as well as co-infections of AU or SA with NAS. Selected NAS demonstrated resistance to growth inhibition after co-culture with AU and SA and were proven to be protective in vitro against AU and SA. Both single infections and co-infections of AU, SA, two selected isolates of S. hominis (NAS1 and NAS2), and two selected isolates of S. chromogens (NAS3 and NAS4) were injected into the murine mammary glands at 105 CFU/mL. After 72 h of inoculation, the results showed that AU, AU–NAS2, and AU–NAS3 expressed severe inflammation with clinical signs of mastitis. The persistence of AU was found for AU, NAS3, and AU–NAS3, whereas the persistence of SA was found for SA–NAS1, SA–NAS3, and SA–NAS, although single SA could not persist. Interestingly, NAS2 in both the single- and co-IMIs with AU or SA resulted in a spontaneous cure 72 h after the IMI. In conclusion, some NAS have beneficial results because they can eliminate S. aureus and S. agalactiae, but some NAS have negative effects because they can support persistent S. agalactiae infection. These results may be used to explain both the advantages and disadvantages of NAS on farms with poor mastitis control. In addition, the beneficial S. hominis may initiate natural live antibiotics and reduce antibiotic resistance problems.

Melanoma-associated antigen-A (MAGE-A), a family of cancer/testis antigens, has been recognized as a potential target molecule for cancer immunotherapy. However, there has been very little information available with regard to this antigen in dogs. This study aimed to investigate the expression of MAGE-A in canine mammary gland tumors (CMTs) using immunohistochemistry and immunoblotting with human monoclonal MAGE-A antibody 6C1. The present study has provided evidence of cross-reactivity of the canine MAGE-A expression with the human MAGE-A antibody in CMTs. The MAGE-A antigens were expressed in moderate- and high-grade malignant CMTs (22.22%, 2/9), but no expression was observed in benign CMTs. The immunohistochemical staining of canine MAGE antigen in CMT cells showed nuclear and nuclear–cytoplasmic expression patterns that may be involved with the mitotic cell division of tumor cells. Molecular weights of the canine MAGE-A antigen presented in this study were approximately 42–62 kDa, which were close to those of other previous studies involving humans and dogs. The findings on this protein in CMTs could supply valuable oncological knowledge for the development of novel diagnostic, prognostic and immunotherapeutic tumor markers in veterinary medicine.

Multifocal hepatic lesions in dogs arise from various benign and malignant liver diseases. Diagnosing these lesions is challenging because clinical signs, hematological data, and serum biochemistry are not definitive indicators. Ultrasound is utilized as a diagnostic imaging tool to evaluate liver parenchyma and detect hepatic lesions. This study aims to investigate the predictive factors that differentiate between benign and malignant multifocal hepatic lesions by examining ultrasound characteristics, blood tests, and serum biochemistry. In total, 43 dogs with multifocal hepatic lesions were included in this study. All dogs were classified into benign hepatic diseases (n = 32) and malignant haptic diseases (n = 11). For all dogs, their liver characteristics, lesion characteristics, and hepatobiliary ultrasound score by ultrasound were evaluated and we collected individual clinicopathological data for analysis. The findings of the univariate analysis revealed significant differences in four hematological and blood chemical parameters (hematocrit, white blood cell count, aspartate transaminase (AST), and alkaline phosphatase (ALP)) and six ultrasonographic parameters (liver parenchymal echogenicity, lesion homogeneity, lesion echogenicity, maximum lesion dimension, average lesion dimension, and hepatobiliary ultrasound score). Using multivariate analysis, only two parameters, hepatobiliary ultrasound score and lesion homogeneity, showed significant differences (p-value < 0.001 and p-value = 0.011, respectively). Additionally, these parameters demonstrated high accuracy in predicting malignant multifocal liver lesions, with accuracy rates of 97.67% and 93.02%, respectively. Therefore, the hepatobiliary ultrasound score and lesion homogeneity are considered effective parameters for screening malignant multifocal liver lesions in dogs.

Glypican-3 (GPC-3) and alpha-fetoprotein (AFP) are considered powerful biomarkers for human hepatocellular carcinoma (HCC). The elevation of GPC-3 and AFP gene expression is commonly found in individual HCC patients. The detection of these biomarkers can be achieved with the examination of blood or tissue samples. Moreover, mRNA expressing GPC-3 and AFP are evaluated for detecting HCC in patients. In veterinary practice, data on GPC-3 and AFP of gene expression remain limited. Therefore, this study aims to evaluate the GPC-3 and AFP gene expression in dogs with HCC compared with other hepatic diseases. Twenty dogs were divided into two groups: HCC (n=6), and non-HCC (n=6). The liver tissue and plasma samples of each group were examined for GPC-3 and AFP gene expression by qPCR. The results showed a no statistical difference in the expression levels of GPC-3 gene in liver and plasma samples of dogs with HCC compared with non-HCC dogs. However, there was a positive correlation between the expression of GPC-3 gene and levels of aspartate transaminase (AST) in the HCC group (p-value = 0.002, R = 0.967). Moreover, the sensitivity, specificity, and accuracy of GPC-3 gene expression were higher than AFP gene expression in the HCC group. Therefore, this study conveys the expression of GPC-3 gene and AFP gene, suggesting a potential association with the development of HCC in dogs. The findings, particularly regarding the GPC-3 gene, could contribute to improved diagnostic methods in the future.