Search

The southern China coast areas are often invaded by typhoons, probably causing the redistribution of heavy metals in sediments. The knowledge of the influence of typhoons on the redistribution of heavy metals along the coasts is limited. The sea-floor sediments from the Leizhou Peninsula (LP) coast, southern China, were sampled to test the spatial distribution of the heavy metal before and after typhoons Barijat and Mangkhut in 2018. Results indicated that the coast suffered from varying levels of As contamination, while only minor enrichments were found in a few locations for other heavy metals. The pollution level on the western LP coast seemed to be higher than on the eastern coast. All heavy metals were mainly provided by terrigenous materials from the natural processes and were less affected by grain sizes. After the typhoon landings, more oxidation conditions promoted the deposits of As and the adsorption of Mo by MnO 2 ., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Accumulative evidence suggests that low folate intake is associated with increased risk of breast cancer. Polymorphisms in genes involved in folate metabolism may influence DNA methylation, nucleotide synthesis, and thus individual susceptibility to cancer. Thymidylate synthase (TYMS) is a key enzyme that participates in folate metabolism and catalyzes the conversion of dUMP to dTMP in the process of DNA synthesis. Two potentially functional polymorphisms [a 28-bp tandem repeat in the TYMS 5'-untranslated enhanced region (TSER) and a 6-bp deletion/insertion in the TYMS 3'-untranslated region (TS 3'-UTR)] were suggested to be correlated with alteration of thymidylate synthase expression and associated with cancer risk., Methods: To test the hypothesis that polymorphisms of the TYMS gene are associated with risk of breast cancer, we genotyped these two polymorphisms in a case-control study of 432 incident cases with invasive breast cancer and 473 cancer-free controls in a Chinese population., Results: We found that the distribution of TS3'-UTR (1494del6) genotype frequencies were significantly different between the cases and controls (P = 0.026). Compared with the TS3'-UTR del6/del6 wild-type genotype, a significantly reduced risk was associated with the ins6/ins6 homozygous variant genotype (adjusted OR = 0.58, 95% CI = 0.35-0.97) but not the del6/ins6 genotype (OR = 1.09, 95% CI = 0.82-1.46). Furthermore, breast cancer risks associated with the TS3'-UTR del6/del6 genotype were more evident in older women, postmenopausal subjects, individuals with a younger age at first-live birth and individuals with an older age at menarche. However, there was no evidence for an association between the TSER polymorphism and breast cancer risks., Conclusion: These findings suggest that the TS3'-UTR del6 polymorphism may play a role in the etiology of breast cancer. Further larger population-based studies as well as functional evaluation of the variants are warranted to confirm our findings.