ABSTRACT
ObjectiveTo investigate the effects of oxidized low density lipoprotein (oxLDL) on autophagy and its effect on Akt/mTOR/p70S6K signaling pathway in human umbilical vein endothelial cells (HUVECs).MethodsThe cultured HUVECs were divided into either an oxLDL or a control group, and treated with 100 μg/ml oxLDL and equal volume phosphate buffer solution respectively.The cells were collected after 6 h and 12 h.Transmission electron microscopy was used to observe the autophagosome.Real-time fluorescence quantitative polymerase chain reaction was used to detect expression levels of microtubule associated protein 1 light chain 3 (LC3) and p62 mRNA.Western blot was used to detect the expression levels of LC3, p62, P-Akt/Akt, P-mTOR/mTOR, and p-p70S6K/p70S6K.Results Compared with the control group, the number of intracellular autophagosome increased obviously (P<0.05), LC3 mRNA and protein expression levels increased significantly (all P<0.05), and p62 mRNA and protein expression levels decreased significantly (all P<0.05) in the oxLDL group.In addition, the phosphorylated protein expression levels of Akt, mTOR and p70S6K in the oxLDL group were significantly decreased than those in the control group (all P<0.01).However, total protein levels of Akt, mTOR, and p70S6K were not significantly different between the oxLDL group and the control group.Conclusion oxLDL may induce the autophagy of HUVECs via inhibiting the Akt/mTOR/p70S6K signaling pathway.
ABSTRACT
<p><b>OBJECTIVE</b>To establish a method for the determination of N-butylbenzene in the workplace atmosphere by gas chromatography.</p><p><b>METHODS</b>N-butylbenzene in the workplace atmosphere was collected by activated charcoal tube, desorbed using carbon disulfide, and determined by capillary column gas chromatography.</p><p><b>RESULTS</b>The method showed a linear relationship within the range of 0∼100 µg/ml. The regression equation was y = 0.870x-0.014, with the correlation coefficient r being 0.999 9. The limit of detection was 0.32 µg/ml. The minimum detectable concentration was 0.21 mg/m³ (with sampled air volume of 1.5 L). The average spike recovery rate was 97.8%∼102.6%. The within-run precision was 3.06% and the between-run precision was 3.64%. The rate of average desorption was 99.6%. The breakthrough volume was 6.34 mg. The sampling efficiency was 100%. The samples could be stored for at least 7 days at room temperature.</p><p><b>CONCLUSION</b>All parameters of the method meet the requirements of GBZ/T 210.4-2008 "Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace" and can be applied for the determination of N-butylbenzene in workplace atmosphere.</p>
Subject(s)
Air , Air Pollutants, Occupational , Benzene Derivatives , Chromatography, Gas , Methods , Linear Models , WorkplaceABSTRACT
<p><b>OBJECTIVE</b>To establish the method of high-performance liquid chromatography (HPLC) for the determination of N-isopropylaniline in workplace air.</p><p><b>METHODS</b>N-isopropylaniline in the air was collected by silicone tube, and was then dissolved by acetonitrile and determined by HPLC-UV detector.</p><p><b>RESULTS</b>There was a linear relationship within the range of 0.0-100.0 µg/ml with the method, and the regression equation was y=22 863x+10 665(r=0.999 9); the detection limit was 0.005 µg/ml, and the minimum detectable concentration was 1.7x10(-3) mg/m3 (3.0 L sampling volume); the average recoveries of standard addition were 96.2%-101.3%. The within-run precision was 2.31%-2.99%, and the between-run precision was 3.21%-4.55%. The average desorption efficiency was 97.6%, the breakthrough volume was more than 8.12 mg, the sampling efficiency waE 100%, and the samples could be stored for at least 7 days at room temperature.</p><p><b>CONCLUSION</b>The indicators ol the method all meet the requirements of GBZ/T 210.4-2008 (Determination methods of air chemicals in workplace), and can be used for the determination of N-isopropylaniline in workplace air.</p>