Evaluation of teaching effect of opening experiments on occupational health and occupational medicine / 中华医学教育探索杂志

Objective:To carry out opening experiments on occupational health and occupational medicine for students majoring in preventive medicine, reform the experimental teaching mode, and explore the teaching methods to improve students' professional quality and scientific research ability.Methods:Opening experiments were carried out in the experimental course of occupational health and occupational medicine for students of preventive medicine major. A total of 147 students majoring in preventive medicine of Batch 2016 were classified as the control group, and the routine confirmatory experiment was carried out in the group; 176 students majoring in preventive medicine of Batch 2017 were classified as the experimental group, and this group carried out opening experiment. The evaluation was made from three aspects: comprehensive evaluation results, teacher self-evaluation and student satisfaction survey. SPSS 22.0 software was used for analysis and comparison by independent-samples t-test and Chi-square test. Results:The theoretical scores of the experimental group and the control group students were (84.37±10.45) vs. (81.44±9.22) ( t=2.68, P=0.008), and the experimental skills scores were (93.66±3.89) vs. (88.41±5.67) ( t=9.51, P<0.001). Questionnaire investigation showed that the students in the opening experimental group were more satisfied with the courses arrangement ( χ2=8.31, P=0.004), group cooperation ( χ2=21.10, P<0.001), assessment form ( χ2 =7.92, P=0.005), improvement of the writing ability of scientific research papers ( χ2 =17.56, P<0.001), improvement of practical skills ( χ2=11.70, P=0.001), logical thinking, language organization and expression ability ( χ2=10.33, P=0.001). They considered the opening experiment was helpful to cultivate innovative thinking and ability, but it had limited effect on the cultivation of employment advantages. And the students considered the opening experiments of setting up professional courses was sufficient and necessary. Conclusion:Carrying out opening experiments for students majoring in preventive medicine is helpful to improve students' professional quality and cultivate their practical ability and scientific research ability.

The mechanism of HBV infection of human trophoblast cell / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To observe the changes of human trophoblast cells after infected with hepatitis B virus.</p><p><b>METHODS</b>HBV positive serum was used to infect human trophoblast cells in vitro. HBsAg in cell culture medium were detected by ELISA method and HBV DNA in cell culture medium and cells were detected by PCR method. HBV fluorescence polymerase chain reaction diagnose kit were used to detect the HBV DNA concentration. Ultra structure of trophoblast cells were observed with transmission electron microscopy (TEM).</p><p><b>RESULTS</b>HBsAg could be detected in infection group by ELISA. Infection group cell culture medium and infection group cells were HBV DNA positive. HBV DNA concentrations in HBV infection cell culture medium in 0, 12, 36, 60, 84 h after extensively PBS washed were < 10(3), 3 x 10(4), 6 x 10(5), 5 x 10(5), 3 x 10(5) copies/mL. HBV infected trophoblast cells were found many forms of endosomes, some of which contents virus like particle.</p><p><b>CONCLUSION</b>HBV might take advantage of clathrin-mediated endocytosis to enter trophoblast cell, which might lead to cell infection or across the cell bar by transcytosis.</p>

A follow-up study on the efficacy of hepatitis B immunoglobulin combining hepatitis B vaccine in infants born to HBsAg positive mothers / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the efficacy of hepatitis B immunoglobulin (HBIG) combining hepatitis B vaccine in high risk infants born to HBsAg positive mothers through a follow-up study program.</p><p><b>METHODS</b>184 infants (4 twin pairs) born to HBsAg carrier mothers who were consecutively recruited from December 2002 to August 2004 were followed. Major HBV serologic markers in all infants were detected by enzyme-linked immunosorbent assay (ELISA) when they were at birth, at 7th, at 24th and at 36th months.</p><p><b>RESULTS</b>7 of the 184 infants were HBsAg positive at birth, making the transplacental intrauterine infection rate of HBV as 3.80% (7/184). 125 infants were followed up at 7th months and 108 infants were followed up at 24th and 36th months. Only 2 of the 7 infants born to HBsAg-positive and HBeAg-positive mothers were persistently sera positive for HBsAg, making the chronic infection rate of HBV as 28.57%. The other 140 infants were HBsAg negative during t he follow-up period. The rate o f detectable anti-HBs i ninfants was 7.02% at birth. After infants were immunized by HBIG combining hepatitis B vaccine, the anti-HBs-positive rate reached 92% at 7th months, and gradually descended thereafter. 72.04% of the infants at 24th and 60% at 36th months showed detectable levels of anti-HBs. There was significant correlation between the produce of anti-HBs in infants and HBsAg-positive at birth while HBsAg-positive and HBeAg-positive in mothers did not relate to the produce of anti-HBs in their infants. Of 39 infants born to HBsAg-positive and HBeAg-positive mothers, 25 showed detectable levels of HBeAg. During the follow-up peirod, HBeAg was still detectable in 2 infants who were also HBsAg positive and the others all became HBeAg-negative but no infant became HBeAg-positive.</p><p><b>CONCLUSION</b>The efficacy of HBIG combining hepatitis B vaccine in high risk infants was fine.</p>

A retrospective study on the association of sexual behavior during pregnancy with intrauterine infection of hepatitis B virus / 中华流行病学杂志

<p><b>OBJECTIVE</b>Case-control study was employed to explore the association of sexual behavior during pregnancy and hepatitis B virus (HBV) intrauterine infection.</p><p><b>METHODS</b>212 HBsAg positive pregnant women were consecutively collected and investigated as objects. Those neonates detected for HBsAg with S/N value > or = 5 by Abbott reagents in periphery sera were selected as cases, others as controls. Information on sexual behavior during pregnancy, maternal HBeAg status and other factors was collected, and were analyzed with univariate analysis, multivariate logistic regression analysis, etc, to explore the association of factors with HBV intrauterine infection.</p><p><b>RESULTS</b>Ten of the 214 neonates were validated as occurrence of HBV intrauterine infection. Sexual behavior in the second trimester during pregnancy, with odd ratios 9.15 (95% CI: 1.10 - 76.28), as well as maternal positivity for HBeAg and HBV DNA, was significantly associated with HBV intrauterine infection, and sequently affirmed by multiple logistic regression analysis. The strength of association increased with frequency of sexual behavior. Interaction analysis suggested that there was synergistic interaction between maternal positivity of HBeAg and sexual behavior in the second trimester.</p><p><b>CONCLUSION</b>Sexual behavior was a newly discovered risk factor for HBV intrauterine infection, which need to be estimated in future studies. Inhibition of virus replication and moderate control of sexual behavior would be helpful to prevent HBV intrauterine infection.</p>

In vitro infection of human hepatoma (Hep G2) cell line by hepatitis B virus positive serum / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To establish a culture system of HBV positive serum infected Hep G2 cells in vitro.</p><p><b>METHODS</b>Hep G2 cells were seeded into six-well cluster dishes, at 1 x 10(-6) cells per well and incubated with 3 ml 10% fetal calf serum/ Dulbecco's modified Eagle's medium (10% FCS/DMEM) at 37 degrees in 5% CO2 air. At 24 h after plating, infection group Hep G2 cells were cultured with 0.5 ml HBV positive serum, in control group HBV negative serum was used, 24 h later the inoculums was removed. The cells were then extensively washed with 0.01 mol/L phosphate-buffered saline (PBS). After washing with PBS, 4 ml 2% FCS/DMEM were added to each well and the medium was collected every 12 h. ELISA method was used to detect HBsAg in culture medium. HBV DNA in cells and culture medium was detected by PCR.</p><p><b>RESULTS</b>In infection group, HBsAg could be detected from cell culture medium from 12 h (after PBS washed) to 84 h. HBV DNA could be detected by PCR in culture medium and cells.</p><p><b>CONCLUSION</b>Infection of Hep G2 cells by HBV positive serum is feasible.</p>