Xenobiotic metabolism in oral tissues, especially in the tongue, has never been reported. In the present study, the metabolic activation/detoxification ability of promutagens in the tongue and the expression levels of related enzymes were investigated. Quantitative PCR analysis of rat tongue demonstrated constitutive messenger RNA (mRNA) expression of numerous drug-metabolizing enzymes. In particular, we detected mRNA, protein expression, and enzymatic activity of cytochrome P450 (CYP)1A1 in the tongue tissue. Metabolic activation of promutagens in the tongue was estimated using benzo[a]pyrene or heterocyclic amines (HCAs), found in cooked meat and tobacco products. Metabolic activation levels of HCAs in the tongue were comparable to those in the liver. In contrast, the expression levels of glutathione-S-transferase (GST) and uridine diphosphate-glucuronosyltransferase (UGT) in the tongue were considerably lower compared with those in the liver, and as a result, the mutagenic activity in the tongue was not decreased by GST- or UGT-dependent conjugation. Treatment of rats with sudan III, a typical inducer of CYP1A1, resulted in markedly increased CYP1A1 mRNA, protein expressions, and CYP1A-dependent enzymatic and mutagenic activities. In addition, CYP1A1 mRNA expression in carcinoma cells (SAS) was induced by sudan III exposure. In conclusion, mutagenic activation of xenobiotics and an increased risk of cancer in the tongue were observed in this study. Furthermore, ingestion of drug-metabolizing enzyme inducers has the potential to increase the metabolic activation in the tongue tissue and increase the risk of biomolecular attack by promutagens.
A urinary bladder tumour was diagnosed in a two-year-old female Maltese with haematuria and pollakiuria on the basis of ultrasonography and pneumocystography findings. The mass was resected, and the bladder was preserved at surgery. Histological and immunohistochemical examination confirmed the tumour to be a rhabdomyosarcoma, which has rarely been reported in small breeds of dog. There was no recurrence of the tumour at the original site in the urinary bladder two months later, when the dog died due to metastasis to the liver. This is believed to be the first report of bladder rhabdomyosarcoma in a Maltese.
A three-year-old male crossbred dog was presented with multiple cutaneous nodules on the dorsum. Unilateral testicular enlargement ensued. Histopathological examination of testicular tissue and the skin lesions revealed a malignant seminoma. Despite the initiation of adjuvant chemotherapy, the dog died three months later due to systemic metastases of the seminoma to the skin, scrotum, eyes, liver, kidney and peritoneum.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.