Research on the formulation and revision of standard limits for antimony,boron and vanadium in the "Standards for Drinking Water Quality (GB5749-2022)" in China / 中华预防医学杂志

China is rich in antimony, boron, and vanadium mineral resources, which have been detected in environmental water bodies and drinking water. During the revision process of the "Standards for Drinking Water Quality (GB5749-2006)", research and evaluation are focused on three indicators: antimony, boron and vanadium. Vanadium is added and the limit value of boron is adjusted. This study reviews and discusses the technical contents related to the revision of the antimony, boron and vanadium, including the environmental presence levels, exposure status, health effects, and the revision of the standard limits of these three indicators. Suggestions are also made for the implementation of this standard.

Recommendations for public health protection against flood disaster / 中华预防医学杂志

Flood disaster is one of the most serious natural disasters in the world, and it could pose an inestimable impact on the affected people. Based on existing laws, regulations, and emergency manuals in China, extensive literature review, epidemiological and related protection evidence, and expert consultation, this study analyzed different health risk factors of flood disaster and proposed a multi-stage, multi-population, and multi-phase comprehensive protection measures for the public in the perspective of pre-event prevention, in-event intervention and post-event rescue strategy, which could provide a scientific basis for improving the level of public health protection against the flood disaster and corresponding health outcomes.

Determination of volatile nitrosamines in urine through gas chromatography-mass spectrometry / 中华预防医学杂志

<p><b>OBJECTIVE</b>To establish a detection method based on gas chromatography-mass spectrometry (GC-MS) for concentrations of volatile nitrosamine compounds in urine, and apply it to the test of real samples.</p><p><b>METHODS</b>Target compounds dichloromethane in urine samples was extracted with dichloromethane through liquid-liquid extraction, then the dichloromethane extract was filtrated, evaporated with nitrogen at 40°C to dryness, and the volume was set with 0.2 ml dichloromethane. Analysis of nine volatile nitroso-compounds were performed with GC-MS under selected ion monitoring mode, external reference method was used for quantification, and the detection limit, repeatability and sensitivity were evaluated. In addition, nine volatile nitroso-compounds of 92 urine samples in a town of Anhui province were measured.</p><p><b>RESULTS</b>A good linear range of 2 - 200 ng/ml (with correlation coefficient 0.9985 - 0.9999) were obtained for the above mentioned nine kinds of analyte, and the lowest examination concentration was 0.05 - 0.50 ng/ml. The addition standard recoveries were 68%-102% with the RSD of 0.4% - 5.5% (n = 3). The detection limits were 0.001 - 0.013 ng/ml urine. The detection rate of N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR), N-nitrosopiperidine (NPIP), N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiphenylamine (NDPhA) were 71% (65), 74% (68), 65% (60), 80% (73), 92% (85), 78% (72), 76% (70), 87% (80), 98% (90), respectively, with the results (0.27 ± 0.12), (0.75 ± 0.29), (0.06 ± 0.02), (0.16 ± 0.07), (23.66 ± 5.18), (1.01 ± 0.35), (0.38 ± 0.11), (2.47 ± 0.52) and (15.13 ± 3.48) nmol/g creatinine.</p><p><b>CONCLUSIONS</b>A gas chromatography-mass spectrometry detect method was developed for low level volatile nitrosamines in urine samples.</p>

Effects of benzene and selenium on telomerase in mouse lymphocytes in vivo / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the effects of benzene and selenium on telomerase in mouse lymphocytes in vivo and evaluate telomerase activity as an early marker of benzene effects on lymphocytes.</p><p><b>METHODS</b>Male Kunming mice were divided randomly into 8 groups, including negative control group, reagent control group, 100 mg/kg benzene group, 200 mg/kg benzene group, 400 mg/kg benzene group, 200 mg/kg benzene + 0.75 mg/kg selenium group, 200 mg/kg benzene + 1.50 mg/kg selenium group and 200 mg/kg benzene + 3.00 mg/kg selenium group, 5 mice in each group. The mice in different groups were treated with different methods, once daily for 5 days. After 48 hours of the final exposure, lymphocytes were separated and the telomerase activities were detected with TRAPELISA.</p><p><b>RESULTS</b>Compared with negative and reagent control groups, the telomerase activity was increased after treatment with different dose of benzene and at the dose of 100 mg/kg benzene group it was significantly increased (P < 0.01). At the dose of 200 mg/kg benzene + 0.75 mg/kg selenium group, it was significantly increased (P < 0.01). Compared with the counterpart treated with 200 mg/kg benzene group, the expression of telomerase was increased at the different concentrations after treatment with benzene combined with selenium and it was significantly increased at the dose of 200 mg/kg benzene + 0.75 mg/kg selenium group (P < 0.05).</p><p><b>CONCLUSION</b>Increased telomerase activity in lymphocytes stimulated by benzene at different concentrations indicates activation and proliferation of these lymphocytes of mice in vivo. Telomerase activity is probably a sensitive early marker of lymphocyte proliferation by benzene. Selenium can upregulate the telomerase activity.</p>

Detection of interaction of binding affinity of aromatic hydrocarbon receptor to the specific DNA by exonuclease protection polymerase chain reaction assay / 中华预防医学杂志

<p><b>OBJECTIVE</b>To establish an exonuclease protection mediated polymerase chain reaction (PCR) assay for the non-radioactive, sensitive detection of the binding of protein and DNA.</p><p><b>METHODS</b>The 1 pmol/L-10 nmol/L 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) dissolved in dimethyl sulphoxide (DMSO), was added into 100 microl SD rat hepatic cytosol in vitro, which contained different amount of aromatic hydrocarbon receptors (AhR) and relative proteins, and ligand-AhR-DRE complex were formed in addition to 1 fmol/L-100 nmol/L DNAs probes containing the sequence of DRE. With the digestion of Exonuclease III and S1 nuclease, free DNAs were digested to oligonucleotide and binding DNA remained due to protein (AhR) protection and be amplified by PCR. The results of PCRs were shown by loading on 2% agarose electrophoresis. DMSO was used as negative control and blank control was set up.</p><p><b>RESULTS</b>Target DNA (285 bp) could be observed in the ligand groups, but not in the control group. The minimal amount of receptor was 2.5 fmol/L and the minimal amount of DNA probes was 2 fmol.</p><p><b>CONCLUSIONS</b>Exonuclease protection mediated PCR assay should be a good non-radioactive tool to quantify the interaction of protein and DNA with high sensitivity and simplicity.</p>

Significance of p53 gene mutation and P53 protein expression abnormality on the prognosis of esophageal cancer: a meta-analysis study / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the prognostic significance of p53 mutation and P53 protein expression abnormality among esophageal cancer.</p><p><b>METHODS</b>The results of 27 random controlled trials from 1990 to 2003 were analyzed by meta-analysis method. The overall positive rate of p53 was 52.9% among the cumulative 2174 cases. Relative hazard (RH) was applied to evaluate the risk of disease and all data were analyzed by Dersimonian-Laird method.</p><p><b>RESULTS</b>The analysis for homogeneity (q statistics test) showed that all eligible studies were with heterogeneity (q = 59.88, P < 0.005). The combined RH was 2.07 and 95% confidence interval was 1.58-2.70.</p><p><b>CONCLUSION</b>Findings showed that p53 was a poor prognosis biomarker for esophageal cancer gene diagnosis but might benefit to the strategy of treatment.</p>

Expression of cyclooxygenase-2 in esophageal squamous cell carcinogenesis / 中华预防医学杂志

<p><b>OBJECTIVES</b>To investigate the expression of cyclooxygenase-2 (cox-2) protein in normal squamous epithelium, squamous dysplasia and squamous cell carcinoma of the esophagus, and to elucidate the role of cox-2 in esophageal carcinogenesis.</p><p><b>METHODS</b>Biopsy specimens of atypical esophageal dysplasia (n = 47) and surgical resection of squamous cell carcinoma (n = 86) were compared with normal esophageal specimens (n = 42) and the expression of cox-2 in those specimens was analyzed by immunohistochemistry and western blotting.</p><p><b>RESULTS</b>A significant elevated cox-2 expression was shown in atypical esophageal squamous dysplasia and squamous cell carcinoma, as compared to that in normal esophageal squamous epithelium, with immunohistochemical stain scores of 2.67 +/- 1.77, 2.19 +/- 1.79 and 0.71 +/- 0.46, respectively. Results of western blotting analysis confirmed those obtained by immunohistochemistry. Cox-2 expression significantly correlated with proliferation activity assessed by proliferating cell nuclear antigen index in dysplastic and carcinomous lesions, respectively, and no such correlation could be found in normal esophageal mucosa. Elevated cox-2 expression was not associated with clinical-pathological features of esophageal squamous carcinoma, including age, gender, tumor size, histological grade, lymph node metastasis and clinical stage.</p><p><b>CONCLUSION</b>Elevated expression of cox-2 in atypical squamous dysplasia and squamous cell carcinoma of the esophagus, which correlated with cell proliferation activity, indicated that cox-2 may be involved in the early stage of squamous carcinogenesis of the esophagus, and may be a target of prevention and treatment for esophageal squamous cell carcinoma.</p>

Expression of telomerase reverse transcriptase in premalignant esophageal squamous dysplasia / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the relationship of human telomerase reverse transcriptase (hTRT) and malignant transformation of esophageal dysplasia.</p><p><b>METHODS</b>Telomerase activity and hTRT expression in esophageal dysplasia (n = 47), squamous cell carcinoma (n = 29) and normal esophagus (n = 11) were detected by telomeric repeat amplification protocol (TRAP) and in situ hybridization, respectively.</p><p><b>RESULTS</b>Telomerase activity was detected in none of the 11 cases of normal esophageal tissues (0%) but in 21 of 47 cases (44.7%) of dysplasia, and in 25 of 29 cases (86.2%) of esophageal squamous cell carcinoma. There were statistically significant differences among the telomerase activity in normal esophagus, esophageal dysplasia, and in squamous cell carcinoma (chi(2) = 5.89, P < 0.05; chi(2) = 11.35, P < 0.01). hTRT mRNA was expressed in none of the 11 cases of normal esophageal tissues (0%) but in 23 of 47 cases (48.9%) of dysplasia, and in 24 of 29 cases (82.8%) of esophageal squamous cell carcinoma. There were statistically significant differences among the expression of hTRT mRNA in normal esophagus, esophageal dysplasia, and in squamous cell carcinoma (chi(2) = 6.99, P < 0.01; chi(2) = 7.32, P < 0.01). Significant correlation was found between the telomerase activity and the expression of hTRT mRNA (chi(2) = 57.91, P < 0.001).</p><p><b>CONCLUSION</b>The mRNA expression of hTRT which paralleled to telomerase activity implied that there was a crucial role to play in regulating the activation of telomerase, and was closely related to the malignant transformation of esophageal dysplasia. hTRT might serve as a new, valuable biomarker to detect esophageal squamous cell carcinoma.</p>

Antisense ERCC1 RNA decreases the repair capability of damaged DNA in lung cancer cells induced by benzoapyrene / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of ERCC1 gene on the repair capability of damaged DNA in lung cancer A549 cells induced by benzo[a]pyrene.</p><p><b>METHODS</b>Recombinant plasmid expressing ERCC1 antisense RNA was constructed and transfected into A549 cells by Lipofectin reagent. The stable-transfected cell colonies were selected by hygromycin. Cell viability was determined by the MTT assay. The level of ERCC1 mRNA was measured by Northern Blot analysis. Single cell gel electrophoresis assay was applied to determine the cellular DNA damage and fifty cells for each group were counted.</p><p><b>RESULTS</b>Seven positive colonies expressing ERCC1 antisense RNA were screened. There was no growth rate difference between the antisense-transfected cells and the parental cells. The endogenous mRNA level in transfected colonies decreased in varied degrees, i.e. 12% approximately 86% of that of the parental cells in Northern Blot assay. After 24 h treatment of 10 micro mol/l benzo[a]pyrene, the repair capability for DNA damage in transfected colonies was reduced to 29% approximately 71% of that of the parental cells. Also, a statistically significant correlation was observed between expression of ERCC1 mRNA and repair capability (r = 0.84).</p><p><b>CONCLUSION</b>Antisense ERCC1 RNA decreased the repair capability for damaged DNA in lung cancer cells induced by benzo[a]pyrene.</p>

Improvement of chemically-activated luciferase gene expression bioassay for detection of dioxin-like chemicals / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To improve the chemically-activated luciferase expression (CALUX) bioassay for detection of dioxin-like chemicals (DLCs) based on the toxicity mechanisms of DLCs.</p><p><b>METHODS</b>A recombinant vector was constructed and used to transfect human hepatoma (HepG2). The expression of this vector was 10-100 folds higher than that of pGL2 used in previous experiments. The transfected cells showed aromatic hydrocarbon receptor (AhR)-meditated luciferase gene expression. The reliability of luciferase induction in this cell line as a reporter of AhR-mediated toxicity was evaluated, the optimal detection time was examined and a comparison was made by using the commonly used ethoxyresoufin-O-deethylase (EROD) activity induction assay.</p><p><b>RESULTS</b>The results suggested that the luciferase activity in recombinant cells was peaked at about 4 h and then decreased to a stable activity by 14 h after TCDD treatment. The detection limit of this cell line was 0.11 pmol/L, or 10-fold lower than in previous studies, with a linear range from 1 to 100 pmol/L, related coefficient of 0.997, and the coefficient of variability (CV) of 15-30%.</p><p><b>CONCLUSION</b>The luciferase induction is 30-fold more sensitive than EROD induction, the detection time is 68 h shorter and the detection procedure is also simpler.</p>