Objective To observe the transport of hepatitis B virus (HBV)-infected peripheral blood mononuclear cells (PBMC)through placental barrier set up by choriocarcinoma trophoblast cells (Bewo cells),and to explore the biological role of PBMC as a carrier for HBV transport.Methods Bewo cells and PBMC were cultured and their proliferation and activity were detected by cell counting kit (CCK)-8.One hundred μL serum containing 5 ×10 6 copy/mL HBV DNA was used to infect PBMC,and cells infected with HBV were labeled by fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE).A co-culture model of Bewo cells and HBV-infected PBMC was set up by transwell chamber. The migration of HBV-infected PBMC was detected by flow cytometry.Realtime fluorescence quantitative polymerase chain reaction method was used to detect HBV DNA contents of PBMC under transwell chamber.Results PBMC and Bewo cells proliferated at around 24 h and entered into growth stagnation at around 120 h.The contents of PBMC labeled by green fluorescent at 0,12,24 and 48 h during co-culture under chamber were (0.445 ±0.021)%,(21 .180 ± 4.653 )%,(34.830 ± 7.156 )% and (64.185 ± 3.161)%,respectively.The amount of PBMC marked green fluorescence increased over prolonged incubation time (F =68.983,P =0.001 ).PBMC HBV DNA contents at 24 and 48 h of co-culture under chamber were (1.925±0.431)×103 copy/mL and (2.565 ±0.361)×103 copy/mL,respectively,indicating that PBMC under chamber were infected with HBV.Conclusions PBMC may be a target for HBV infection in extrahepatic tissues.Placental trophoblastic barrier built by transwell chambers may provide new ideas to investigate HBV transmission across the placenta in vitro .

Objective To study the relationship between placenta HBsAg in HBsAg positive pregnant women and serum hepatitis B virus (HBV) markers,HBV DNA levels in newborns.Methods Placenta HBsAg was detected by immunohistochemical affinity hormone-biotin complex (ABC) method in 155 HBsAg positive pregnant women.Serum HBV markers in newborns were detected by enzyme-linked immunosorbent assay (ELISA).Serum HBV DNA levels of newborns were detected by real-time fluorescence quantitative polymerase chain reaction (PCR).The positive rates were compared using x2 test.Results HBsAg was expressed with different levels in various types of cells of placenta in 155 pregnant women.The total placenta HBsAg positive rate was 37.4％ (58/155),and those in decidual cells,trophoblastic cells,villous mesenchymal cells and villous capillary endothelial cells were 37.4％ (58/155),25.8％ (40/155),18.7％ (29/155) and 7.1％ (11/155),respectively.The HBsAg positive rates of placenta gradually decreased from decidual cells of the maternal surface to villous capillary endothelial cells of the fetal surface (tendency x2 =43.01,P=0.00).The positivity of placenta HBsAg was associated with both HBsAg and HBeAg in newborns (x2 =4.88,P＜0.05 and x2 =3.86,P＜0.05,respectively),while that was not associated withanti-HBe and anti-HBc in newborns (x2 =3.36,P＞0.05 and x2 =0.00,P＞ 0.05,respectively).The risk of HBsAg positive in newborns was higher when HBsAg was positive in villous capillary endothelial cells and villous mesenchymal cells (OR=5.31,95 ％CI=1.38-20.40 and OR=3.33,95％CI=1.16-9.52,respectively).The risk of HBeAg positive in newborns was higher when HBsAg was positive in trophoblastic cells and villous mesenchymal cells (OR=3.04,95 ％CI=1.45-6.39 and OR=3.05,95 ％ CI=1.32-7.03,respectively).However,placenta HBsAg positive was not associated with HBV DNA positive in newborns (x2 =0.09,P＞0.05).Conclusion The risk of neonatal HBV serological markers positive is higher when the HBsAg positive placental cells are closer to fetal surface,which indicates that HBsAg enters fetal blood circulation by means of cell transferring layer by layer.

Objective To study the relationships between serum hepatitis B virus (HBV) DNA level in chronic HBV infected mothers, free maternal DNA in newborns' peripheral blood and HBV infection of newborns. Methods Free maternal DNA in newborns' peripheral blood was amplified by allele-specific polymerase chain reaction (As-PCR) and heminested polymerase chain reaction (heminPCR). Serum HBV DNA of pregnant women were detected by fluorescence quantitative real-time PCR. The relationships between mothers' serum HBV DNA level, mother-to-fetus DNA transfer and newborns HBV infection were analyzed by SPSS 13. 0 software. Results Thirty-six pairs of motherfetus informative cases were selected and free maternal DNA in the peripheral blood was detected in 26newborns (72. 2%). Statistical analysis indicated that mother-to-fetus DNA transfer was not related with HBsAg, HBV DNA DOsitive in newborns (Fisher exact Drobabilities were 0. 278 and 1.000,respectively; both P > 0. 05), while it was related with HBV infection in the peripheral bloodmononuclear cell (PBMC) of newborns (Fisher exact probability was 0. 026, P<0. 05). Freematernal DNA transfer was not related with mother HBV DNA level (X2 = 2. 097, P>0. 05). Therisk of HBV DNA positive in newborns increased with mother serum HBV DNA increasing ( total X= 62. 21, P<0. 05; tendency X2 =58. 46, P<0. 05). There was no relationship between motherserum HBV DNA level and PBMC HBV DNA positive in newborns (total X2 =4. 82, P>0. 05).Conclusions DNA transfer from HBV infected mother to fetus is related with PBMC HBV infection innewborns, which could be a risk factor of HBV infection in newborns. The risk of serum HBV DNApositive in newborns increases with mother serum HBV DNA level increasing.

Objective To understand the status quo of medical students' integrity in examinations and to explore the influencing factors. Methods 2013-2015 undergraduate students from Clinical Medi-cine, Preventive Medicine and other professional subjects were included in Shanxi Medical University. A total of 221 questionnaires were issued for each grade by stratified random sampling. The database was built with EpiData 3.1. All statical analyses were performed with SPSS software (version 22.0) by means of chi-square test and binary logistic regression. Results Among the 600 medical students, 16.5% of the students had cheating. A statistically significant difference was observed in the cheating rate among the medical stu-dents in terms of gender, grade, academic performance, medical knowledge, memory, family factors, and invigilators' attitude (P<0.05). Litter pressure from the family, the teacher's proctoring is rigorous invigilation, and top scores were the protective factors for medical students' cheating in exams. Conclusion Through the analysis of the influencing factors for the medical students' integrity in examinations, corresponding measures are formulated to provide reference for relevant medical personnel in various medical colleges and universities.

Objective:To explore the effect of team positive psychological intervention on psychological state and coping style of nurses after being impacted by life events.Methods:From September 2020 to January 2021, 84 nurses who had suffered life events in Shanxi Provincial People's Hospital were selected by the convenient sampling method. According to the enrollment time, they were divided into the experimental group ( n=42) and the control group ( n=42) . The nurses in the control group were not give external intervention measures, while nurses in the experimental group adopted team positive psychological intervention. After 6 weeks of intervention, the Chinese version of Psychological Resilience Scale, Symptom Checklist 90 (SCL-90) and Simple Coping Style Questionnaire were used to compare changes in the psychological resilience level, mental health level and coping style of nurses in the two groups. Results:After intervention, the scores of toughness, strength and optimism dimensions and the total scores of Psychological Resilience Scale in the experimental group were significantly higher than those in the control group, and the differences were statistically significant ( P<0.05) . The total score of SCL-90 in the experimental group was significantly lower than that in the control group, and the difference was statistically significant ( P<0.05) . The score of positive coping dimension of nurses in experimental group was significantly higher than that in control group, and the score of negative coping dimension was significantly lower than that in control group, and the differences were statistically significant ( P<0.05) . Conclusions:Team positive psychological intervention can improve psychological resilience and mental health level of nurses who are impacted by life events. At the same time, it can also encourage them to adopt active coping methods to face problems, which is conducive to improving quality of nursing.

Objective:To explore the association between statins and colorectal cancer and provide evidence for the prevention of colorectal cancer.Methods:Literatures about statins and colorectal cancer published from January 2000 to January 2020 were retrieved from CNKI, Wanfang data, PubMed and Cochrane Library database. The literatures which met the inclusion criteria were collected, and the Newcastle-Ottawa Scale and Jadad score were used to assess the studies. Meta-analysis was performed with statistical software Revman 5.0 and Stata 12.1.Results:A total of 31 studies, involving more than 1.62 million subjects, were included in the analysis. The case-control study ( RR=0.93, 95% CI: 0.88-0.98), the cohort study ( RR=0.75, 95% CI: 0.63-0.88) and the randomized controlled trial ( RR=0.79, 95% CI: 0.65-0.97) showed moderate protective effect of statins. Using statin <5 years ( RR=0.86, 95% CI: 0.76-0.96), average daily dosage ≥34 mg ( RR=0.81, 95% CI: 0.66-0.98) and lipid-soluble statins ( RR=0.86, 95% CI: 0.74-0.99) also had preventive effect on colorectal cancer; while lovastatin ( RR=1.07, 95% CI: 1.00-1.14) increased the risk of colorectal cancer. Conclusion:Statins have protective effect on colorectal cancer.

Background The incidence rate of missed abortion is increasing year by year, but the etiology has not been fully elucidated. Adverse pregnancy history and exposure to polycyclic aromatic hydrocarbons (PAHs) may increase the risk of missed abortion. Objective To investigate the interaction between adverse pregnancy history and PAHs exposure on missed abortion in early pregnancy, and to provide evidence for the etiologic research of missed abortion. Methods A total of 114 pregnant women diagnosed with missed abortion in the Department of Obstetrics of the First Hospital of Shanxi Medical University from March to December 2019 were selected as the case group, and 139 pregnant women who visited the same hospital for voluntary induced abortion in the same period as the control group, to collect basic information and medical information of abortion, stillbirth, intrauterine growth retardation, and other adverse pregnancy history. Abortion villus tissues were collected to detect PAH-DNA adducts levels, stratified by pregnancy and adverse pregnancy history and grouped by quartile method: Q₁ (< 404.61 ng·L⁻¹), Q₂ (404.61−453.75 ng·L⁻¹), Q₃ (453.76−506.72 ng·L⁻¹), and Q₄ (≥506.73 ng·L⁻¹). SPSS 25.0 statistical software was used for χ² test and multiple logistic regression, and additive and multiplicative models were used to investigate the interaction between adverse pregnancy history and PAH-DNA adducts level on missed abortion. The PAH-DNA adducts were grouped by tertiles and quartiles, and P₃₃, P₅₀, P₆₇ and P₇₅ were used as data cut points for sensitivity analysis. Results The proportion of adverse pregnancy history in the case group (32.46%) was higher than that in the control group (12.23%) (P < 0.001). Among 160 subjects with≥2 pregnancies, the proportion of adverse pregnancy history in the case group (57.81%) was higher than that in the control group (17.71%) (P < 0.001). The results of χ² test stratified by pregnancy for different PAH-DNA adducts levels between the two groups showed that the PAH-DNA adducts level was associated with missed abortion in subjects with≥2 pregnancies (χ²=10.14, P=0.017). Being further stratified by adverse pregnancy history, the PAH-DNA adducts level in subjects with no adverse pregnancy history was associated with missed abortion (χ²=9.70, P=0.021). The results of logistic regression analysis showed that adverse pregnancy history (OR=5.88, 95%CI: 2.79−12.39) and PAH-DNA adducts (OR=3.01, 95%CI: 1.22−7.40) increased the risk of missed abortion, but no interaction between them was found. The relative excess risk of interaction (RERI), the attributable percentage of interaction (AP), and the synergy index (SI) and its 95%CI were 0.60 (95%CI: −0.58−1.77), 0.74 (95%CI: −0.83−2.30), and 0.20 (95%CI: 0.01−5.43), respectively. Conclusions Adverse pregnancy history and PAH-DNA adducts in pregnant women may increase the risk of missed abortion. The effect of the interaction between them on the occurrence of missed abortion is not supported by the current study.