ABSTRACT
Methicillin-Resistant Staphylococcus aureus (MRSA) represents one of the major causes of nosocomial infections, leading to high mortality. Surfaces in clinics, as well as the attending uniform and the hands of the dental doctor can be MRSA reservoirs. Having this in mind, the purpose of this study was to evaluate the presence of Methicillin-Sensitive Staphylococcus aureus (MSSA) and MRSA on dental medicine equipment surfaces. 354 Samples were collected from six equipment surfaces in six attendance areas before and after patient consultation and cultured in a selective medium. Polymerase Chain Reaction (PCR) was used to confirm the identity of bacterial strains as MRSA or MSSA. Data analysis was performed with chi-square tests with Bonferroni correction. It was observed 55.6% of uncontaminated samples. Contamination was: 17.5% MRSA (5.9% of samples collected before patient attendance and 11.6% after); 39.3% MSSA (14.1% collected before and 25.2% after). The prevalence of MRSA and MSSA was significantly higher after patient care. Integrated Clinic represented the most contaminated attendance area (MRSA - 41.7%, MSSA - 51.2%), the chair arm rest was the most contaminated surface for MRSA (29.7%) and the dental spittoon the most contaminated surface for MSSA (23.5%). Although a low level of contamination was observed, dental clinics, through patients possibly carrying bacteria, may be reservoirs for MRSA and MSSA transmission, and might contribute to potential nosocomial infections.
ABSTRACT
Thyroid cancer therapy is based on surgery followed by radioiodine treatment. The incorporation of radioiodine by cancer cells is mediated by sodium iodide symporter (NIS) (codified by the SLC5A5 gene), that is functional only when targeted to the cell membrane. We aimed to evaluate if NIS expression in thyroid primary tumors would be helpful in predicting tumor behavior, response to therapy and prognosis. NIS expression was addressed by qPCR and immunohistochemistry. In order to validate our data, we also studied SLC5A5 expression on 378 primary papillary thyroid carcinomas from The Cancer Genome Atlas (TCGA) database. In our series, SLC5A5 expression was lower in carcinomas with vascular invasion and with extrathyroidal extension and in those harboring BRAFV600E mutation. Analysis of SLC5A5 expression from TCGA database confirmed our results. Furthermore, it showed that larger tumors, with locoregional recurrences and/or distant metastases or harboring RAS, BRAF and/or TERT promoter (TERTp) mutations presented significantly less SLC5A5 expression. Regarding immunohistochemistry, 12/211 of the cases demonstrated NIS in the membrane of tumor cells, those cases showed variable outcomes concerning therapy success, prognosis and all but one were wild type for BRAF, NRAS and TERTp mutations. SLC5A5 mRNA lower expression is associated with features of aggressiveness and with key genetic alterations involving BRAF, RAS and TERTp. Mutations in these genes seem to decrease protein expression and its targeting to the cell membrane. SLC5A5 mRNA expression is more informative than NIS immunohistochemical expression regarding tumor aggressiveness and prognostic features.
ABSTRACT
BACKGROUND: Activation of the mTOR pathway has been observed in thyroid cancer, but the biologic consequences regarding tumor behavior and patient prognosis remain poorly explored. METHODS: We aimed to evaluate the associations of the mTOR pathway with clinicopathologic and molecular features and prognosis through the immunocharacterization of pmTOR and pS6 expression (as readouts of the pathway) in a series of 191 papillary thyroid carcinomas. RESULTS: pmTOR expression was associated with distant metastases (P = .05) and persistence of disease (P = .05). Cases with greater expression of pmTOR were submitted to more 131I treatments (r[102] = 0.2; P = .02) and a greater cumulative dose of radioactive iodine (r[100] = 0.3; P = .01). Positive pmTOR expression showed to be an independent risk factor for distant metastases (odds ratio = 18.2; 95% confidence interval 2.1-157.9; P = .01). In contrast, pS6 expression was associated with absence of extrathyroid extension (P = .001), well-defined tumor margins (P = .05), and wild-type BRAF status (P = .01). There was no correlation between the expression of pmTOR and pS6 expression (r[140] = 0.1; P = .3). CONCLUSION: pmTOR expression is an indicator of aggressive, metastatic papillary thyroid carcinoma, being possibly implicated in refractoriness to therapy, while pS6 expression is associated with less aggressive pathologic features. Further studies are needed to understand better the biologic consequences of activation of the mTOR pathway in the behavior of thyroid cancer, namely the contribution of other pmTOR downstream effectors.
