ApoE transiently regulates hippocampus amyloid-beta deposition to stable learning and memory ability in adult rats exposed in sevoflurane.

Objective: Post-operative cognitive dysfunction (POCD) is a common central nervous system complication after surgery. Inhaled anesthetic sevoflurane is thought to have harmful effects on the developing and aged nerves, but its effects on adults' nervous system are less studied and the mechanism is not clear. Methods: Male adult rats were divided into control group and sevoflurane group. Rats from sevoflurane group were received 3.2% sevoflurane + carrier gas (1 L/min O2+1 L/min air) for 2 h, while control group received carrier gas for 2 h. Each group was subsequently divided into 3 subgroups according to the Day 1, Day 3, Day 7 after sevoflurane anesthesia. Morris Water Maze, amyloid-beita (Abeta) and apolipoprotein E (ApoE) mRNA in hippocampus were analyzed. Then, adult ApoE-/- rats were also divided into control group and sevoflurane group. Each group was divided into 3 subgroups according to Day 1, Day 3 and Day 7. Abeta mRNA and protein expression in hippocampus were analyzed. Results: Compared with the control group, hippocampal Abeta mRNA and protein expression in rats from sevoflurane group significantly increased in hippocampus on Day 7, while ApoE mRNA and protein expression increased on Day 1 and Day 3. There was no difference in times of crossing platforms, time during platform, times across platform quadrant and time percent during platform quadrant between each group. Compared with the control group, hippocampal Abeta and ApoE-/- rats in sevoflurane group did not change. Conclusion: ApoE modulates hippocampal Abeta deposition and stabilizes learning and memory ability in adult rats after sevoflurane exposure, but this effect is not constant.

[Pollution characterization and source apportionment of polybrominated diphenyl ethers in autumn air of Xi'an].

Air samples in gas and particle phases were collected using a high volume active sampler from August to October in 2008 at Xi'an for evaluating the pollution level of polybrominated diphenyl ethers (PBDEs). Lower brominated PBDEs and BDE-209 were analyzed via GC-MS and GC/ECD, respectively. The total concentrations (gas plus particle phases) of 12 PBDEs were ranged from 37.43 to 620.30 pg/m3, with an average of 216.28 pg/m3, while tri- to hexa-brominated congeners (Sigma11 PBDEs) ranged from 16.32 to 86. 49 pg/m3, BDE-209 ranged from 16. 34 to 576.01 pg/m3. Tri- to tetra-brominated congeners existed mainly in gas phase, tetra- to hexa-brominated congeners were predominated in particle phase, and BDE-209 was detected only in particle phase. The proportion of PBDEs in particle phase increased with bromine number. Gas-particle partition coefficient of PBDEs was well correlated with sub-cooled liquid vapor pressure, and the partitioning of PBDEs between gas and particle phases were close to equilibrium. Correlation analysis indicated that all the PBDEs have good coefficients except BDE-85. Source analysis indicated that PBDEs in the atmosphere of Xi'an were mainly from the Penta-BDE and Deca-BDE contamination.

[Pollution characterizations and source apportionment of polycyclic aromatic hydrocarbons in air during domestic heating season of Xi'an].

TSP samples and gas phase air samples were collected by an improved high volume active air sampler during domestic heating season in Xi'an, and the concentrations of polycyclic aromatic hydrocarbons (PAHs) were analyzed via GC-MS. The results showed that average concentrations of sigma 16 PAHs in TSP and gas phase were (108.15 +/- 41.44) ng/m3, (260.14 +/- 99.84) ng/m3, respectively. Two and three ring PAHs dominated in the gas phase, while more than four ring PAHs were mainly adsorbed on the particle phase. Good correlation was found between gas-particle partition coefficient and the respective sub-cooled vapor pressures of PAHs. A significant correlation was also found between partition coefficient and temperature, and the regression equation was put forward by stepwise linear regression method. Ratio analysis illustrated that coal burning and vehicle exhaust were the main source of PAHs in Xi' an. Contribution of each source was calculated by factor analysis and multiple linear regression. Partial correlation analysis was applied to study the relationship between air pollution indexes and some representative PAHs of individual factors, which indicated some PAH had same source to SO2 and NO2.