High quality diet attenuated the positive association between polychlorinated biphenyls and premature mortality among middle-aged and older adults.

OBJECTIVE: Polychlorinated biphenyls (PCBs) have been reported to be a risk factor for premature death, while a high diet quality is thought to lower mortality risk. We aimed to examine whether PCBs were associated with higher all-cause and cause-specific mortality risk and whether such associations could be modified by the diet quality among US middle-aged and older adults. METHODS: Included were 1259 participants aged 40 years or older from the 1999-2004 National Health and Nutrition Examination surveys. Exposure to PCBs was assessed in non-fasting serum samples, and mortality status was ascertained through December 31, 2019 using the public-use, linked mortality files. Diet quality was assessed using the Healthy Eating Index-2015 based on 24-h dietary recalls. Cox proportional hazard regression was applied to assess the associations of different PCB congener groups with mortality and the modifying effect by the diet quality. RESULTS: During a median follow-up of 17.75 years, 419 deaths occurred, including 131 from cardiovascular disease (CVD) and 102 from cancer. Serum concentrations of dioxin-like PCBs and non-dioxin-like PCBs were significantly associated with all-cause mortality, with hazard ratios (HRs) of 1.84 (95% confidence interval [CI], 1.10, 2.99) and 1.82 (1.09, 3.03) for extreme-tertile comparisons. A significant interaction was noted between dioxin-like PCBs and diet quality (P for interaction: 0.012), with a substantially more pronounced association among participants with a low diet quality (HR, 3.47; 95% CI: 1.29, 9.32), compared to those with a high diet quality (HR, 0.98; 95% CI: 0.40, 2.43). A similar weaker association was observed for total PCBs in participants with a high diet quality (P for interaction: 0.032). However, effect modifications by diet quality were not noted for the associations between different PCB groups and CVD mortality. CONCLUSIONS: While our findings need to be validated in other populations and mechanistic studies, they may suggest that a high quality diet could potentially attenuate the harmful effects of chronic PCB exposure.

Current Helicobacter pylori Infection Is Associated with Early Liver Injury: A Cross-Sectional Study in the General Population.

Early prevention of liver injury by controlling risk factors deserves concern because of the heavy liver disease burden. Helicobacter pylori (HP) infection affects half of the world's population and the relationship between it and early liver damage is unclear. This study focuses on assessing the correlation between them in the general population to provide clues to prevent liver disease. A total of 12,931 individuals underwent liver function and imaging tests as well as 13C/14C-urea breath tests. Results showed that the detection rate of HP was 35.9%, and the HP-positive group had a higher rate of liver injury (47.0% versus 44.5%, P = 0.007). Specifically, Fibrosis-4 (FIB-4) and alpha-fetoprotein levels in the HP-positive group were higher whereas the serum albumin level was lower. HP infection would raise the percentage of elevated aspartate aminotransferase (AST; 2.5% versus 1.7%, P = 0.006), elevated FIB-4 (20.2% versus 17.9%, P = 0.002), and abnormal liver imaging (31.0% versus 29.3%, P = 0.048). Most of these results remained stable after covariate adjustment but, for liver injury and liver imaging, the conclusions only held in young people (ORliver injury, odds ratio of liver injury, 1.127, P = 0.040; ORAST, 1.33, P = 0.034; ORFIB-4, 1.145, P = 0.032; ORimaging, 1.149, P = 0.043). Overall, HP infection might be associated with early liver injury, particularly in youth, suggesting that people with early liver injury should pay more attention to HP infection to prevent the occurrence of severe liver diseases.

Effects of Guangzhou seasonal climate change on the development of Aedes albopictus and its susceptibility to DENV-2.

The susceptibility of Asian tiger mosquitoes to DENV-2 in different seasons was observed in simulated field environments as a reference to design dengue fever control strategies in Guangzhou. The life table experiments of mosquitoes in four seasons were carried out in the field. The susceptibility of Ae. albopictus to dengue virus was observed in both environments in Guangzhou in summer and winter. Ae. albopictus was infected with dengue virus by oral feeding. On day 7 and 14 after infection, the viral load in the head, ovary, and midgut of the mosquito was detected using real-time fluorescent quantitative PCR. Immune-associated gene expression in infected mosquitoes was performed using quantitative real-time reverse transcriptase PCR. The hatching rate and pupation rate of Ae. albopictus larvae in different seasons differed significantly. The winter hatching rate of larvae was lower than that in summer, and the incubation time was longer than in summer. In the winter field environment, Ae. albopictus still underwent basic growth and development processes. Mosquitoes in the simulated field environment were more susceptible to DENV-2 than those in the simulated laboratory environment. In the midgut, viral RNA levels on day 7 in summer were higher than those on day 7 in winter (F = 14.459, P = 0.01); ovarian viral RNA levels on day 7 in summer were higher than those on day 7 in winter (F = 8.656, P < 0.001), but there was no significant difference in the viral load at other time points (P > 0.05). Dicer-2 mRNA expression on day 7 in winter was 4.071 times than that on day 7 in summer: the viral load and Dicer-2 expression correlated moderately. Ae. albopictus could still develop and transmit dengue virus in winter in Guangzhou. Mosquitoes under simulated field conditions were more susceptible to DENV-2 than those under simulated laboratory conditions.

Semi-field life-table studies of Aedes albopictus (Diptera: Culicidae) in Guangzhou, China.

BACKGROUND: Aedes albopictus is a major vector for several tropical infectious diseases. Characterization of Ae. albopictus development under natural conditions is crucial for monitoring vector population expansion, dengue virus transmission, and disease outbreak preparedness. METHODS: This study employed mosquito traits as a proxy to understanding life-table traits in mosquitoes using a semi-field study. Ae. albopictus larval and adult life-table experiments were conducted using microcosms under semi-field conditions in Guangzhou. Stage-specific development times and survivorship rates were determined and compared under semi-field conditions in different seasons from early summer (June) to winter (January), to determine the lower temperature limit for larval development and adult survivorship and reproductivity. RESULTS: The average egg- hatching rate was 60.1%, with the highest recorded in October (77.1%; mid-autumn). The larval development time was on average 13.2 days (range, 8.5-24.1 days), with the shortest time observed in September(8.7 days; early autumn) and longest in November (22.8 days). The pupation rates of Ae. albopictus larvae were on average 88.9% (range, 81.6-93.4%); they were stable from June to September but decreased from October to November. The adult emergence rates were on average 82.5% (range, 76.8-87.9%) and decreased from July to November. The median survival time of Ae. albopictus adults was on average 7.4 (range, 4.5-9.8), with the shortest time recorded in September. The average lifetime egg mass under semi-field conditions was 37.84 eggs/female. The larvae could develop into adults at temperatures as low as 12.3°C, and the adults could survive for 30.0 days at 16.3°C and still produce eggs. Overall, correlation analysis found that mean temperature and relative humidity were variables significantly affecting larval development and adult survivorship. CONCLUSION: Ae. albopictus larvae could develop and emerge and the adults could survive and produce eggs in early winter in Guangzhou. The major impact of changes in ambient temperature, relative humidity, and light intensity was on the egg hatching rates, adult survival time, and egg mass production, rather than on pupation or adult emergence rates.

[Determination of methamphetamine in human blood using microwave extraction-gas chromatography].

A method was developed for the determination of methamphetamine (MAM) in human blood using microwave extraction-gas chromatography (GC). To improve the extraction efficiency, experimental parameters on the extraction, including such as extraction solvent and its amount, pH value of blood sample, extraction time and temperature were investigated. Comparing with conventional liquid-liquid extraction method, the microwave extraction showed better efficiency under the optimal conditions. The optimal conditions were as follows: the pH of blood sample at 13, ethyl acetate as extraction solvent, extraction at 30 degrees C for 8 min. The average recovery of MAM with this extraction method was 81.4%, and the relative standard deviation was 6.4%. The limit of detection was 220 microg/L for MAM in the blood. Using this method, MAM need not be derivatized and can be separated from the matrix. The results indicate that the developed method is rapid, accurate and sensitive, and can be used for the determination of MAM in blood samples.