Construction of a recombinant plasmid of BC022687 and identification of its expression and localization in CHO cells / 中华男科学杂志

<p><b>OBJECTIVE</b>To construct a mammalian expression plasmid of the BC022687 gene and investigate the expression and localization of the fusion protein in Chinese hamster ovary (CHO) cells.</p><p><b>METHODS</b>The BC022687 coding sequence was amplified by polymerase chain reaction (PCR) and subcloned into the pEGFP-C1 vector carrying the gene of green fluorescence protein (GFP). After the target region was sequenced, the recombinant plasmid was transfected into CHO cells, and its expression in the CHO cells was determined by Western blot. The localization of GFP-tagged BC022687 in the CHO cells was observed by laser scanning confocal microscopy.</p><p><b>RESULTS</b>BC022687 was successfully cloned into the mammalian expression vector pEGFP-C1, with the restriction fragment length of 950 bp. The expression of the fusion protein was confirmed, with the relative molecular weight of 64 000. The GFP-tagged BC022687 protein was mainly localized in the cytoplasm, and also presented in the centrioles in the transfected CHO cells.</p><p><b>CONCLUSION</b>The successful construction of the plasmid expressing BC022687 in CHO cells has laid a foundation for further studies on the role of this protein in ciliogenesis.</p>

A cross-sectional study about the effects of residential exposure to power transmission line on human nervous system symptoms and hematology / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the possible effects on nervous system and health condition under the exposure to electromagnetic field.</p><p><b>METHODS</b>Take the resident around the power transmission line as the objects and were divided into 3 groups by the distance from the power transmission line 20 m, 100 m and 500 m, respectively. Some living conditions and health conditions were recorded by face-to-face the questionnaire survey, and Hematological indices of each groups were examined including IgG, IgM, leukocyte formulae, erythrocyte, hemoglobin and platelet.</p><p><b>RESULTS</b>There was no significant difference in each group, according exposure of daily life, such as drinking and smoking (P > 0.05). Compared with the each distance groups, it was presented significant difference between the distance from the power transmission line and the incidence of headache or dizziness, insomnia and easy weary and so on (P < 0.05). In hematology aspect, with the horizontal distance from the power transmission line decreasing, PLT level of residents was reductive and the difference was statistically significant (P < 0.001), whereas leukocyte formulae, erythrocyte, hemoglobin, IgG and IgM had no significant difference among each group (P < 0.05).</p><p><b>CONCLUSION</b>Closely exposure to electromagnetic field may induce headache and so on and decrease the level of PLT.</p>

Establishment of biological limit value of urinary S-phenylmercapturic acid for occupational exposure to benzene / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish the biological exposure limit values of urinary S-phenylmercapturic acid (SPMA) for assessing occupational exposure to benzene.</p><p><b>METHODS</b>Study participants were selected from 55 workers of benzene exposures below 32.5 mg/m(3). The concentration of personal exposure to benzene was measured by gas chromatography and sampled with personal sampler. The urine samples were collected at the end of work shift and individual internal exposure level was evaluated by determination of SPMA in urine by HPLC/MS method. Comparison of external and internal exposure was assessed by the relative internal exposure (RIE) index.</p><p><b>RESULTS</b>The benzene exposure level ranged from 0.71 to 32.17 mg/m(3) (geometric mean 6.98 mg/m(3), median 7.50 mg/m(3)). The urinary SPMA at the end of the work shift were significantly correlated with benzene exposure, (microg/g Cr) = -8.625 + 18.367X (mg/m(3)), r = 0.8035, (P < 0.01). According to the occupational exposure limit for benzene in China and calculation of regression equation, the expected value of urinary SPMA was 101.58 microg/g Cr. Mean level of biotransformation of per mg/m(3) benzene to urinary SPMA was 18.23 microg/g Cr and the metabolic efficiencies of benzene transformation to urinary SPMA decreased with benzene exposure increased.</p><p><b>CONCLUSION</b>Based on abroad documents and data, biological limit value for occupational exposure to benzene in China is recommended as follows: 100 microg/g Cr (47 micromol/mol Cr) for SPMA in the urine at the end of shift.</p>

Effect of NS-398 on cyclooxygenase-2 expression and proliferation of HepG2 cells / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate anticancer effect and molecular mechanism of N-[(Cyclohexyloxy)-4-nitrophenyl] methanesulfonamide on HepG2 cells in vitro.</p><p><b>METHODS</b>HepG2 cells were treated with various concentrations (100, 200, 300, 400 micromol/L) of NS-398 [selective for cyclooxygenase 2 (COX-2) inhibition]. Cell growth was measured by MTT method, DNA fragmentation gel analysis was used to analyze the apoptosis cells, DNA ploidy and apoptotic cell percentage were examined by flow cytometry (FCM). PGE2 concentration was measured by radioimmunoassay method. The expressions of COX-2 were also examined by Western blot analysis.</p><p><b>RESULTS</b>NS-398 inhibited HepG2 cell proliferation and induced apoptosis in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased and quiescent G1 phase was accumulated with NS-398 concentration increasing. The IC50 of 24 hours was 300 micromol/L. The release of PGE2 was significantly reduced in HepG2 cells with the values of NS-398 being (0.70 +/- 0.02), (0.48 +/- 0.02), (0.29 +/- 0.01) and (0.18 +/- 0.01) respectively, as compared with control group (0.03 +/- 0.01). NS-398 could inhibit the activity and expression of COX-2, with higher concentration, it can significantly down-regulate the expression of COX-2 (t = 3.736, 1.623, 1.810, 2.587, P < 0.01).</p><p><b>CONCLUSION</b>NS-398 might significantly inhibit the proliferation of HepG2 cells and induce apoptosis. The mechanisms were related with the accumulation of quiescent G1 phase and the inhibition of COX-2 activity.</p>

High-performance liquid chromatographic determination of urinary trans, trans-muconic acid excreted by workers occupationally exposed to benzene / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the relationship between trans, trans-muconic acid (ttMA) as benzene metabolite of occupational workers and benzene concentration in air.</p><p><b>METHODS</b>A rapid and sensitive high-performance liquid chromatography was developed to determine the level of urinary ttMA. ttMA was extrated from urinary samples in liquid-liquid phase a ODS (2) (5u) column (phi 4.6 mm x 150 mm) and detected at wavelength 264 nm in a UV detector using vanillic acid as an internal standard. The mobile phase was acetaticacid/tetrahydrofuran/methanol/water (v/v, 1:2:10:87). The method was validated with 56 urine samples collected from occupationally benzene-exposed individuals.</p><p><b>RESULTS</b>A correlation coefficient (r = 0.9963) was found for ttMA ranging 0.10-10.00 microg/mL. The limit of detection was 0.10 microg/mL. The recovery and reproducibility were generally over 90%. There was a positive correlation between ttMA and benzene level in air. The equation was Y = 0.859 + 0.108C (before work, r = 0.6200) or Y = 1.980 + 0.179C (after work, r = 0.7930).</p><p><b>CONCLUSION</b>This method can be used to determine and control the level of urinary ttMA in those who are occupationally exposed to benzene.</p>