Objective: To explore the trichloroethylene-induced alteration of methylation on the promoter region of SET and related mechanisms in hepatic L-02 cells. Methods: L-02 cells were treated with different concentrations of TCE(0 mmol/L, 1 mmol/L, 2 mmol/L, 4 mmol/L, 8 mmol/L) for 24 h. The genomic DNA were then extracted and modified by bisulfite sodium. The DNA methylation was then analyzed using bisulfite sequencing PCR (BSP). Results: The overall methylation on promoter region of SET was decreased along with the increased concentrations of TCE in hepatic L-02 cells. Moreover, 73 CpG islands were found abnormally altered, among which 9 were predicted in transcriptional factor binding regions. Conclusion The decreased levels of CpG islands in the transcriptional factor binding region may contribute to the elevation of SET in TCE-induced hepatotoxicity.

Objective: To develop a new solid sorbent tube for capturing glycidyl methacrylate (GMA) in workplace air, and establish a complete set of method. Methods: GMA in workplace air was captured by the new solid sorbent tube filled with carbon aerogel adsorbent, desorbed with solution of 50% (V/V) dimethylformamide-carbon disulfide, separated through capillary chromatographic column, and then analyzed by gas chromatography-flame ionization detector. Results: The linear range of GMA was 0.38-604.80 mg/L, and the related coefficient was 0.999 82. The within-run and the between-run precision were 1.11%-2.80% and 2.53%-4.84% respectively. The average desorption efficiency was 93.20%-94.97%. The minimum quantification concentration and The minimum quantification concentration were 0.02 and 0.07 mg/m³ respectively (3.00 L sample) . Samples could be stored for at least 8 days at room temperature. Conclusion The newly developed solid sorbent tube and its complete set of gas chromatography method is simple, and has high sensitivity and precision, so it can be used for sampling and quantitative detection of GMA in workplace air.

Objective: To further explore TCE-induced hepatotoxicity and its mechanisms by identification of trichloroethylene (TCE) induced abnormal histone methylation in human liver cells. Methods: L-02 cells were treated with 0 and 8 mmol/L TCE for 24 h. Histones were extracted by acid. Liquid chromatography electrospray ionization tandem mass spectrometry (ESI-LC-MS/MS) were used to identify and quantify TCE related histone methylations. TCE induced abnormal methylation of H3K79 me2 and H3K79 me3 were validated by Western blot analysis. The further analysis of the function of histone abnormal methylation modifications were done by single cell gel electrophoresis (SCGE) and Western blot analysis of p53 and ɤH2AX. Results: After treatment with TCE for 24 h in L-02 cells, the 36 TCE related histone methylation sites in 28 peptide segments were identified by MS. After treatment with TCE in concentrations of 0 and 8.0 mmol/L in L-02 cells for 24 h, the relative expression level of histone H3K79 me3 were 1.00±0.06, 0.70±0.09 (t=15.01, P=0.015); the relative expression level of histone H3K79 me2 were 1.00±0.05, 0.74±0.07 (t=16.69, P=0.018); the Olive Tail Moment about DNA damage were 1.46±0.28, 3.12± 0.68 (t=15.22, P=0.018); the relative expression levels of p53 were 1.00±0.04, 1.24±0.04 (t=18.71, P= 0.012); and the relative expression levels of ɤH2AX were 1.00 ± 0.03, 1.56 ± 0.11 (t=8.32, P=0 045). Conclusion TCE can induce changes in the relative expression level of H3K79 me2 and H3K79 me3 in L-02 cell, and induce DNA damage, suggesting that TCE may induce changes in the relative expression level of H3K79 me2 and H3K79 me3 by DNA damage.

Objective:To develop a new solid sorbent tube for simultaneously capturing ethylene oxide (EO) , propylene oxide (PO) and epichlorohydrin (ECH) in air, and establish a complete set of method.Methods:In June 2018, EO, PO and ECH in air were captured by the new solid sorbent tube filled with carbon aerogel adsorbent, desorbed with solution of 5% ( V/V) methanol-methylene chloride, separated through capillary chromatographic column, and then analyzed by gas chromatography-flame ionization detector. Results:The linear ranges of EO, PO and ECH were 0.24-960.00, 0.60-2384.00 and 0.12-472.40 mg/L respectively, and the related coefficients were between 0.99995-0.99997. The relative standard deviations ( RSD) within the group were 1.66%-4.09%, 1.36%-4.43%, and 1.99%-5.65%, respectively, and the RSD between the group were 2.69%-4.95%, 2.77%-5.30%, and 3.27%-6.67%, respectively. The average desorption efficiencies were 88.25%-94.50%, 98.17%-98.60%, and 97.79%-101.04%, respectively. The samples could be stored at 4 ℃ refrigerator for at least 27 days. Conclusion:The newly developed solid sorbent tube filled with carbon aerogel adsorbent and its complete set of gas chromatography method could be used for sampling and quantitative detection of EO, PO and ECH in workplace air.

Objective:To develop a new solid sorbent tube for simultaneously capturing ethylene oxide (EO) , propylene oxide (PO) and epichlorohydrin (ECH) in air, and establish a complete set of method.Methods:In June 2018, EO, PO and ECH in air were captured by the new solid sorbent tube filled with carbon aerogel adsorbent, desorbed with solution of 5% ( V/V) methanol-methylene chloride, separated through capillary chromatographic column, and then analyzed by gas chromatography-flame ionization detector. Results:The linear ranges of EO, PO and ECH were 0.24-960.00, 0.60-2384.00 and 0.12-472.40 mg/L respectively, and the related coefficients were between 0.99995-0.99997. The relative standard deviations ( RSD) within the group were 1.66%-4.09%, 1.36%-4.43%, and 1.99%-5.65%, respectively, and the RSD between the group were 2.69%-4.95%, 2.77%-5.30%, and 3.27%-6.67%, respectively. The average desorption efficiencies were 88.25%-94.50%, 98.17%-98.60%, and 97.79%-101.04%, respectively. The samples could be stored at 4 ℃ refrigerator for at least 27 days. Conclusion:The newly developed solid sorbent tube filled with carbon aerogel adsorbent and its complete set of gas chromatography method could be used for sampling and quantitative detection of EO, PO and ECH in workplace air.

Objective:To understand the epidemiological and etiological characteristics of hand-foot-mouth disease (HFMD) in the Nanshan District of Shenzhen City from 2019 to 2022 and to provide a scientific basis for HFMD prevention in the area.Methods:Epidemiological data on HFMD in Shenzhen Nanshan District from 2019 to 2022 in the China Information System for Disease Control and Prevention were analyzed using descriptive research methods.Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to analyze the etiology characteristics of clinical specimens from HFMD patients. The VP1 gene of the dominant pathogen coxsackievirus A6 (CV-A6) was amplified and sequenced. SepMan Pro of DNASTAR software was used for sequence assembly and MegAlign was used for nucleotide homology analysis.Results:A total of 13 195 HFMD cases were reported in Shenzhen Nanshan District from 2019 to 2022, with an average annual incidence rate of 186.18/100, 000. Summer and autumn are the main onset seasons and children under 7 years old were the main population, accounting for 93.1%. The male-to-female ratio is 1.44∶1. A total of 451 clinical HFMD specimens were detected in the laboratory, including 403 positive (87.36%) and 48 negative (10.64%). The main pathogens were CV-A6 (63.03%), coxsackievirus A16 (CV-A16) (27.79%), coxsackievirus A4 (CV-A4) (4.71%), coxsackievirus A10 (CV-A10) (1.99%), Echovirus 11 (Echo-11) (0.25%), and uncertain type accounted for 2.23%, with no detection for enterovirus71 (EV71) type. The nucleotide homology of the 13 CV-A6 strains ranged from 94.0%?99.6%, and the nucleotide homology with the prototype strain Gdula ranged 84.1%?85.8%. The results of phylogenetic tree showed that all 13 CV-A6 strains in Nanshan District were of the D3a genotype.Conclusions:FHFMD in Nanshan District of Shenzhen City in 2019-2022 shows obvious differences in population and time distribution. Therefore, it is necessary to strengthen publicity and education on HFMD prevention and control in the summer and fall seasons and among key populations. CV-A6 and CV-A16 are the dominant strains of HFMD in Nanshan District, Shenzhen in recent years, so the monitoring of the dominant strains should be improved.

OBJECTIVE: To establish a methodology for simultaneous detection of chloromethyl methyl ether( CMME) and bis-chloromethyl ether( BCME) in workplace air by gas chromatography. METHODS: CMME and BCME in workplace air were collected with absorption solution which was also derivatization solution. The derivative products were extracted using n-hexane alkaline medium. The extracts were separated by capillary column and detected with electron capture detector.The quantification was performed by use of standard curves. RESULTS: The linearity ranges of CMME and BCME were2. 00-80. 00 and 1. 32-52. 80 ng,respectively. The correlation coefficients were both 0. 999 93. The minimum detectable concentrations were both 0. 030 μg / m3 and the minimum quantification concentrations were both 0. 100 μg / m3( 7. 50 L sample). The recovery rates were 99. 35%-101. 00% and 97. 99%-101. 70% respectively. The within-run relative standard deviations( RSD) were 2. 73%-4. 46% and 2. 61%-3. 82% respectively,and the between-run RSD were3. 10%-5. 50% and 3. 89%-5. 38% respectively. The sampling efficiencies were 92. 43%-96. 25% and 91. 43%-94. 03%respectively. The samples were stable at room temperature for at least 15 days. CONCLUSION: This method is suitable for simultaneous detection of CMME and BCME in workplace air.

OBJECTIVE: To establish a method for detecting thiocyanate in human urine by high performance liquid chromatography( HPLC) with 2,3,4,5,6-pentafluorobenzyl bromide as precolumn derivatization reagent.METHODS: Thiocyanate in human urine was derived with 2,3,4,5,6-pentafluorobenzyl bromide, and separated by poroshell 120EC-C18 column with acetonitrile:deionized water( 60:40,V/V) as mobile phase.detected by HPLC,Liquid chromatography-UV detector was used for determination.The wavelength was 212.00 nm.RESULTS: Good linearity was obtained in the range of 0.05-10.32 mg/L with the correlation coefficient of 0.999.The detection limit was 6.31 μg/L and the minimum detection concentration was 63.10 μg/L( 0.1 mL urine).The recovery rate was 95.1%-102.9%.The within-run relative standard deviation( RSD) and the between-run RSD were 0.9%-1.0% and 0.9%-2.1%,respectively.The urine samples could be stored at 4 ℃ for 7 days.CONCLUSION: This method has high sensitivity,good specificity and sample preparation,which can be used for detecting urine thiocyanate in occupational population.

OBJECTIVE: To establish a detecting method for sulfur dioxide in workplace air by molecular sieve solid adsorption tube sampling and ion chromatography. METHODS: Air samples were collected by molecular sieve solid adsorption tubes,desorbed by distilled water,oxidized by hydrogen peroxide in weak base system,separated by anion exchange chromatography and detected by conductivity detector. RESULTS: The good linearity range of sulfur dioxide was0. 10-16. 00 mg/L,and the correlation coefficient was 0. 999 8. The detection limit was 0. 02 mg/L,the minimum detectable concentration was 0. 01 mg/m3. The average desorption efficiency was 96. 53%-99. 35%. The within-run and between-run relative standard deviations were 1. 73%-3. 65% and 1. 80%-4. 46% respectively. The samples could be stored at room temperature for at least 14 days. CONCLUSION: This method is suitable for detecting sulfur dioxide in workplace air.

OBJECTIVE: To explore the feasibility of simultaneous detection of 45 kinds of common organic compounds in workplace air by solvent desorption-gas chromatography method.METHODS: A total of 45 kinds of common organic compounds such as benzene,1,2-dichloroeyhane,n-hexane and trichloroethylene in workplace air were collected with activated carbon tube and desorbed with carbon disulfide,separated by capillary chromatographic column,and detected with flame ionization detector.RESULTS: There was good linear relationship in the selected range.The correlation coefficients was 0.999 92-0.999 99.The detection limit was 0.03-0.30 mg/L and the minimum detectable concentration range was 0.01-0.20 mg/m~3( sample volume was 3.00 L).The average desorption efficiencies was 75.4%-105.7%.The within-run and between-run relative standard deviations were 0.4%-6.7% and 1.8%-7.9%,respectively.The sampling efficiency was 91.9%-100.0%.CONCLUSION: The method is simple,high sensitivity and good precision,which can be used for simultaneous detection of 45 kinds of common coexisting organic compounds in workplace air.