1.
In vitro cytotoxicity of silver nanoparticles and zinc oxide nanoparticles to human epithelial colorectal adenocarcinoma (Caco-2) cells.
Song, Y, Guan, R, Lyu, F, Kang, T, Wu, Y, Chen, X
Mutation research. 2014;:113-8
Abstract
With the increasing applications of silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) in foods and cosmetics, the concerns about the potential toxicities to human have been raised. The aims of this study are to observe the cytotoxicity of Ag NPs and ZnO NPs to human epithelial colorectal adenocarcinoma (Caco-2) cells in vitro, and to discover the toxicity mechanism of nanoparticles on Caco-2 cells. Caco-2 cells were exposed to 10, 25, 50, 100, 200μg/mL of Ag NPs and ZnO NPs (90nm). AO/EB double staining was used to characterize the morphology of the treated cells. The cell counting kit-8 (CCK-8) assay was used to detect the proliferation of the cells. Reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione (GSH) assay were used to explore the oxidative damage of Caco-2 cells. The results showed that Ag NPs and ZnO NPs (0-200μg/mL) had highly significant effect on the Caco-2 cells activity. ZnO NPs exerted higher cytotoxicity than Ag NPs in the same concentration range. ZnO NPs have dose-depended toxicity. The LD50 of ZnO NPs in Caco-2 cells is 0.431mg/L. Significant depletion of SOD level, variation in GSH level and release of ROS in cells treated by ZnO NPs were observed, which suggests that cytotoxicity of ZnO NPs in intestine cells might be mediated through cellular oxidative stress. While Caco-2 cells treated with Ag NPs at all experimental concentrations showed no cellular oxidative damage. Moreover, the cells' antioxidant capacity increased, and reached the highest level when the concentration of Ag NPs was 50μg/mL. Therefore, it can be concluded that Ag NPs are safer antibacterial material in food packaging materials than ZnO NPs.
2.
Screening for oesophageal cancer.
Yang, S, Wu, S, Huang, Y, Shao, Y, Chen, XY, Xian, L, Zheng, J, Wen, Y, Chen, X, Li, H, et al
The Cochrane database of systematic reviews. 2012;:CD007883
Abstract
BACKGROUND Oesophageal cancer is a global heath problem. The prognosis for advanced oesophageal cancer is generally unfavourable, but early-stage asymptomatic oesophageal cancer is basically curable and could achieve better survival rates. The two most commonly used tests are cytologic examination and endoscopy with mucosal iodine staining. The efficacy of the screening tests is controversial, and the true benefit and efficacy of screening remains uncertain because of the potential lead-time and length-time biases. This review was conducted to examine the evidence for the efficacy of screening for oesophageal cancer (squamous cell carcinoma and adenocarcinoma). OBJECTIVES To determine the efficacy of early screening, using endoscopy with iodine staining or cytologic examination, in reducing mortality from oesophageal cancer in asymptomatic individuals from high-risk and general populations. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 8), The Cochrane Library (2012, Issue 8), MEDLINE (1950 to August 2012), EMBASE (1980 to August 2012), Allied and Complementary Medicine (AMED) (1985 to August 2012), Chinese Biomedical Database (CBM) (January 1975 to August 2012), VIP Database (January 1989 to August 2012), China National Knowledge Infrastructure (CNKI) (January 1979 to August 2012), and the Internet. We also searched reference lists, conference proceedings, and databases of ongoing trials. There was no restriction on language or publication status in the search for trials. SELECTION CRITERIA We included only randomised controlled trials (RCT) of screening versus no screening for oesophageal cancer. Randomisation of groups or clusters of individuals was acceptable. DATA COLLECTION AND ANALYSIS Two review authors independently scanned the titles and abstracts from the initial search for potential trials for inclusion. We did not find any trials that met the inclusion criteria. MAIN RESULTS The electronic search identified 3482 studies. Two authors independently reviewed the references. The reports of 18 studies were retrieved for further investigation. None met the eligibility criteria for a RCT investigation of the effects of screening versus no screening for oesophageal cancer. AUTHORS' CONCLUSIONS There were no RCTs that determined the efficacy of screening for oesophageal cancer. Non-RCTs showed a high incidence and the reported better survival after screening could be caused by selection bias, lead-time and length-time biases. RCTs are needed to determine the efficacy of screening for oesophageal cancer.