We tested some resin-based composites used in dentistry for their estrogenic activity. A sealant based on bisphenol-A diglycidylether methacrylate (bis-GMA) increased cell yields, progesterone receptor expression, and pS2 secretion in human estrogen-target, serum-sensitive MCF7 breast cancer cells. Estrogenicity was due to bisphenol-A and bisphenol-A dimethacrylate, monomers found in the base paste of the dental sealant and identified by mass spectrometry. Samples of saliva from 18 subjects treated with 50 mg of a bis-GMA-based sealant applied on their molars were collected 1 hr before and after treatment. Bisphenol-A (range 90-931 micrograms) was identified only in saliva collected during a 1-hr period after treatment. The use of bis-GMA-based resins in dentistry, and particularly the use of sealants in children, appears to contribute to human exposure to xenoestrogens.ImagesFigure 1. AFigure 1. BFigure 2.Figure 3. AFigure 3. BFigure 4. AFigure 4. BFigure 5. AFigure 5. BFigure 6. AFigure 6. BFigure 7. AFigure 7. BFigure 8.Figure 9.Figure 10.
We present data showing that some foods preserved in lacquer-coated cans and the liquid in them may acquire estrogenic activity. Hormonal activity was measured using the E-screen bioassay. The biological activity of vegetables packed in cans was a result of plastic monomers used in manufacturing the containers. The plastic monomer bisphenol-A, identified by mass spectrometry, was found as a contaminant not only in the liquid of the preserved vegetables but also in water autoclaved in the cans. The amount of bisphenol-A in the extracts accounted for all the hormonal activity measured. Although the presence of other xenoestrogens cannot be ruled out, it is apparent that all estrogenic activity in these cans was due to bisphenol-A leached from the lacquer coating. The use of plastic in food-packaging materials may require closer scrutiny to determine whether epoxy resins and polycarbonates contribute to human exposure to xenoestrogens.ImagesFigure 1.Figure 2. AFigure 2. BFigure 3. AFigure 3. BFigure 4.Figure 5. AFigure 5. BFigure 6.
The development of reliable gene expression profiling technology is having an increasing impact on our understanding of lung cancer biology. Our study aimed to determine any correlation between the phenotypic heterogeneity and genetic diversity of lung cancer. Microarray analysis was performed on a set of 46 tumor samples and 45 paired nontumor samples of nonsmall cell lung cancer (NSCLC) samples to establish gene signatures in primary adenocarcinomas and squamous-cell carcinomas, determine differentially expressed gene sequences at different stages of the disease and identify sequences with biological significance for tumor progression. After the microarray analysis, the expression level of 92 selected genes was validated by qPCR and the robust Bonferroni test in an independent set of 70 samples composed of 48 tumor samples and 22 nontumor samples. Gene sequences were differentially expressed as a function of tumor type, stage and differentiation grade. High upregulation was observed for KRT15 and PKP1, which may be good markers to distinguish squamous-cell carcinoma samples. High downregulation was observed for DSG3 in stage IA adenocarcinomas.Lung cancer is the leading cause of cancer death in the United States 1 and worldwide. The two major forms of lung cancer are nonsmall cell lung cancer (NSCLC %85% of all lung cancers) and small-cell lung cancer (SCLC %15%). NSCLC can be divided into three major histological subtypes: squamous-cell carcinoma, adenocarcinoma and large-cell lung cancer. Smoking causes all types of lung cancer but is most strongly linked with SCLC and squamous-cell carcinoma, while adenocarcinoma is the most frequent type in patients who have never smoked.2-5 Patients with early-stage NSCLC who undergo curative resection still have a substantial risk of developing metastases. The 5-year survival rates for patients with Stage IA and IB NSCLC are only 67 and 57%, respectively.
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.