Susceptibility of Aedes albopictus and Aedes aegypti to three imported Chikungunya virus strains, including the E1/226V variant in Taiwan.

BACKGROUND/PURPOSE: An E1/226V variant Chikungunya virus (CHIKV) efficiently transmitted by Aedes albopictus to humans poses a significant threat to public health for those areas with the presence of Aedes albopictus, including Taiwan. METHODS: We infected three imported CHIKV isolates including the E1/226V variant with Ae. albopictus and Aedes aegypti in the laboratory to understand the disease risk. Viral RNA was measured by real time reverse transcription polymerase chain reaction. RESULTS: The viral susceptibility varied by virus strain and mosquito species and strain. The Asian virus strain started to replicate at 5-6 days post infection (dpi) with the maximum virus yield, ranging from 10(3.63) to 10(3.87) at 5-10 dpi in both species. The variant CHIKV Central/East/South African (CESA) virus genotype replicated earlier at 1 dpi with the maximum virus yield ranging from 10(5.63) to 10(6.52) at 3-6 dpi in Ae. albopictus females while the nonvariant virus strain replicated at 1-2 dpi with the maximum virus yield ranging from 10(5.51) to 10(6.27) at 6-12 dpi. In Ae. aegypti, these viruses replicated at 1-2 dpi, with maximum yields at 4-5 dpi (range from 10(5.38) to 10(5.62)). CONCLUSION: We concluded that the risk of CHIKV in Taiwan is high in all distribution areas of Ae. aegypti and Ae. albopictus for the CESA genotype and that the E1/226V variant virus strain presents an even higher risk.

The XRCC1 399Gln polymorphism and the frequency of p53 mutations in Taiwanese oral squamous cell carcinomas.

DNA repair gene polymorphisms have been implicated as susceptibility factors in cancer development. It is possible that DNA repair polymorphisms may also influence the risk of gene mutation. The 399Gln polymorphism in the DNA repair gene XRCC1 has been indicated to have a contributive role in DNA adduct formation, sister chromatid exchange, and an increased risk of cancer development. Two hundred thirty-seven male oral squamous cell carcinomas (OSCCs) were included in a study to investigate the role of the XRCC1 194Trp, 280His, and 399Gln polymorphisms on p53 gene mutation. PCR-single-strand conformation polymorphism and DNA sequencing were used to analyze the conserved regions of the p53 gene (exons 5-9). The XRCC1 genotype was determined by PCR-RFLP. Nineteen (8.02%) of the 237 OSCCs had a Gln/Gln genotype. One hundred six (43.88%) of the 237 OSCCs showed p53 gene mutations at exons 5-9. The OSCC patients with a Gln/Gln genotype exhibited a significantly higher frequency of p53 mutation than those with an Arg/Gln and an Arg/Arg genotype. After adjustment for age, cigarette smoking, areca quid chewing, and alcohol drinking, the Gln/Gln genotype still showed an independent association with the frequency of p53 mutation (odd ratio, 4.50; 95% confidence interval, 1.52-13.36). The findings support the hypothesis that XRCC1 Arg399Gln amino acid change may alter the phenotype of the XRCC1 protein, resulting in a DNA repair deficiency. This study also suggests an important role for the XRCC1 399Gln polymorphism in p53 gene mutation in Taiwanese OSCCs.

Safrole-DNA adducts in human peripheral blood--an association with areca quid chewing and CYP2E1 polymorphisms.

It has been recently demonstrated that safrole (4-allyl-1,2-methylenedioxybenzene)-DNA adducts are present in oral cancer tissue from patients who have chewed areca quid (AQ) containing high concentration of safrole. In this study, the presence of safrole-DNA adducts in peripheral white blood cells from 88 subjects with a known AQ chewing history and 161 matched controls were studied with the aim of identifying the adducts as a biomarker for safrole exposure. This study also analyzed the correlation between the level of safrole-DNA adducts and polymorphism of the CYP2E1 gene, alone and in combination with the GST M1 and GST T1-deletion polymorphisms. The results demonstrated the presence of safrole-DNA adducts in 83 (94.32%) of the DNA samples from subjects with current AQ chewing history and 21 (13.04%) of the control samples without known AQ chewing habit ( [Formula: see text] ). Individuals with at least one CYP2E1 c2 allele had a significant higher frequency of safrole-DNA adducts (odds ratio (OR), 4.00; 95% confidence interval (CI), 1.03-15.53) than those with the CYP2E1 c1c1 genotype while chewing less than 20 areca quids per day. In conclusion, this study demonstrates the presence of safrole-DNA adducts in peripheral blood lymphocytes (PBL), and the presence of these safrole-DNA adducts is correlated with AQ chewing. In addition, the CYP2E1 would seem to play an important role in the modulation of safrole-DNA adduct formation.