Meta-analysis on the contents of trace elements in workers with occupational exposure to lead / 中华劳动卫生职业病杂志

Objective: To quantitatively evaluate the content differences of trace elements in workers with occupational exposure to lead. Methods: In January 2021, relevant literatures on the contents of trace elements in workers with occupational exposure to lead published from 1990 to 2020 were searched through CNKI, Wanfang, VIP, PubMed, web of science and Embase. Screened and extracted the literatures, and evaluated the quality of the included literatures with Newcastle Ottawa Scale. Meta analysis was performed with Review Manager 5.3 software, and standardized mean difference (SMD) and its 95% confidence interval were used as effect indicators. Results: A total of 20 literatures were included, and the quality scores were 5-7. The results of Meta-analysis showed that compared with the control group, the contents of blood zinc (SMD=-1.01, 95%CI: -1.53, -0.49) , hair zinc (SMD=-0.17, 95%CI: -0.33, -0.01) , hair copper (SMD=-0.50, 95%CI: -1.01, 0) , hair iron (SMD=-3.91, 95%CI: -5.80, -2.03) and hair manganese (SMD=-1.09, 95%CI: -2.02, -0.15) in occupational lead exposure group were significantly lower (P<0.05) . Compared with the control group, the content of cobalt in hair of occupational lead exposure group (SMD=1.41, 95%CI: 0.72, 2.10) was higher, and the difference was statistically significant (P<0.05) . There was no significant difference in the contents of blood chromium, blood copper, blood iron, blood manganese, blood selenium and hair nickel between the two groups (P>0.05) . Conclusion: Workers with occupational exposure to lead have abnormal trace elements.

Determination of methyl isobutyl ketone in urine by headspace coupled with gas chromatography-mass spectrometry / 中华劳动卫生职业病杂志

Objective: To establish a method for the determination of methyl isobutyl ketone (MIBK) in urine samples by headspace-gas chromatography-mass spectrometry. Methods: Automatic headspace sampling technique was adopted to optimize the headspace conditions (headspace bottle heating temperature and equilibration time) and gas chromatographic conditions. A total of 5 ml samples were taken and added with 3.0 g ammonium sulfate into a 20 ml headspace bottle. After heated at 60 ℃ for 30 mins, gas from the upper part of headspace bottle was injected into gas chromatography with an injection volume of 100 μl. The target was separated by HP-5MS UI (30 m×0.25 mm×0.25 μm) capillary column and then detected by mass spectrometry detector. The retention time and external standard method were used for qualitative and quantitative analysis of MIBK in samples, respectively. Results: The standard curve of MIBK showed significant linearity between 20.0-1 000.0 μg/L. The standard curve was y=62.9x-652.5, and the correlation coefficient r=0.9998. The detection limit of MIBK was 5.0 μg/L and the quantification limit of MIBK was 16.0 μg/L. The average recovery rate was 95.3%~100.2% at three spiked concentrations of low (50.0 μg/L) , medium (200.0 μg/L) and high (500.0 μg/L) . The intra-day and inter-day precisions were 1.7%~3.8% (n=6) and 1.2%~4.0% (n=6) respectively. This method was stable for the determination of MIBK, and the urine could be kept 14 d at -20 ℃ without significantly loss. Conclusion: This method is proved to be simple, practical and highly sensitive. It can satisfy the request for the determination of urine samples of workers exposed to MIBK.

Effects of ER Stress and PUMA on 5-FU-induced Liver Cell Injury and Apoptosis / 中山大学学报(医学科学版)

@#【Objective】To investigate the role of ER stress and PUMA in 5-FU-induced liver cells injury and apoptosis.【Methods】We established 5-FU-induced liver injury models by intraperitoneally injecting the isodose 5-FU to 10 PUMA knockout mice(PUMA-KO)and 20 PUMA Wild type mice(PUMA-WT). Meanwhile,10 WT mice were intraperitoneally injected with 4-Phenylbutyric acid,the ER stress inhibitor. In the control group,10 KO mice and 20 WT mice were given the same amount of normal saline.After the modeling,serum and liver tissues of the mice were collected to assess the degree of liver pathological injury,measure the expression levels of ALT and AST in serum,and detect the expression levels of PUMA and GRP78 in liver tissues. The changes of these indicators in different treatment groups were observed and compared.【Results】Compared with the WT control group,serum ALT and AST levels were significantly increased in the 5-FU group,H&E staining showed punctate focal necrosis,accompanied by hemorrhage and inflammation. TUNEL staining showed apoptotic cells were markedly added(Z = 3.78,P < 0.001),and expressions of PUMA and GRP78 were obviously augmented,suggesting that both PUMA and ER stress were involved in 5-FU-induced liver cells injury and apoptosis. Then,in the 4-PBA group,we found that the expression levels of GRP78 and PUMA were down-regulated,and apoptosis of liver cells was reduced under the same dose of 5-FU(χ~2= 32.99,Z = 3.78,P <0.001),further confirming that both PUMA and ER stress were involved in this process. Subsequently,it was found that,when induced by the same dose of 5-FU,cleaved caspase-3 staining showed that the liver apoptosis signal of the PUMA knockout mice was lower than the WT mice(χ~2= 33.99,Z = 3.78,P < 0.001),but the difference in the expression of GRP78 between the two groups was not statistically significant. In summary,the expression of PUMA was reduced and the apoptosis of liver cells was attenuated after the inhibition of ER stress;PUMA knockdown could not influence the activation of ER stress but alleviated apoptosis of liver cells.【Conclusions】PUMA mediates ER stress-up-regulated liver cells apoptosis in 5-FU-induced Chemotherapeutic liver injury.