Aim To discover the change of synaptic plasticity by supplementing DHA during development period in rats. Method We divided Wistar rats into two groups: fish oil group and control group. The fish oil rats were supplemented with fish oil(5?10~3 ml?g-1 body weight) by gavage daily. The control rat was supplemented with NS of the same dose. 90 days later, each rat was hippocampus of anaesthetized and LTP and LTD were recorded at hippocampus of the same rat. Result Compared to the control group, DHA group presented an obvious increase in PS LTP, while no changes were found in EPSP LTP. On the other hand,DHA group demonstrated an obvious canceling effect on both EPSP and PS LTD. Conclusion There exist effects on synaptic plasticity after supplement with DHA. It may be one of the factors that DHA improves learning and memory.

Objective To observe the concentration changes of plasma cortisol ( Cor ) and adrenocorticotropic hormone( ACTH) in preterm infants with respiratory failure receiving ventilation treatment. Methods The 30 preterm in-fants with respiratory failure requiring mechanical ventilation were selected as the preterm group with respiratory failure, and 32 full term infants with respiratory failure in need of mechanical ventilation were selected as the term infant group with respiratory failure, and 52 preterm infants( preterm control group) and 17 full term infants( term control group) were selected as controls. All the cases were chosen from Neonatal Intensive Care Unit of Anhui Province Children′s Hospital during January to December 2014. The levels of plasma Cor and ACTH were measured and analyzed. Results (1) Cor level:on the 3rd day, the level of plasma Cor in the preterm group with respiratory failure was lower than that in the term group with respiratory failure[262. 50(162. 00-332. 50) nmol/L vs 531. 00(244. 75-644. 00) nmol/L], and higher than those in the preterm control group[199. 50(49. 05-388. 95) nmol/L] and term control group[120. 00(43. 90-191. 00) nmol/L], the differences were statistically significant(all P<0. 05). On the 7th day, the level of plasma Cor in the preterm group with respiratory failure was lower than that in the term group with respiratory failure[128. 00(65. 85-244. 00) nmol/L vs 222. 00 (131. 50-377. 85) nmol/L], the difference was statistically significant(P<0. 05). (2) ACTH level:on the 3rd day, the level of ACTH in the preterm group with respiratory failure was higher than those in the other groups[38. 20(25. 18-76. 65) pmol/L vs 24. 60(19. 03-38. 20) pmol/L vs 22. 30(14. 40-40. 60) pmol/L vs 24. 20(13. 90-45. 65) pmol/L], the differences were statistically significant(P<0. 05). On the 7th day, the concentration of ACTH in the preterm group with respiratory failure was lower than those in the term group with respiratory failure[16. 55(12. 78-31. 80) pmol/L vs 29. 85(18. 23-54. 65) pmol/L], and there were statistical differences(P<0. 05). Conclusions The newborns with respiratory failure were in criti-cal stress, the level of plasma Cor in the preterm infants with respiratory failure was lower than that of the term infants with respiratory failure, while the level of ACTH in the former was higher than that in the latter. And when the stress disap-peared, both of the plasma Cor and ACTH recovered to the normal level.

Objective: To explore the associations of aggressive behavior with self-esteem with suicide risk in college students. Methods: A total of 4 154 college students in Suzhou, Hefei and Ma’anshan were enrolled in our study by multistage cluster sampling method during October to December 2017. Demographic characteristics, suicide risk, aggression and self-esteem of participants were evaluated by Suicidal Behaviors Questionnaire-Revised (SBQ-R), Buss & Perry Aggression Questionnaire-Chinese Version (AQ-CV) and Rosenberg Self-esteem Questionnaire separately. Aggression and self-esteem were divided into three levels, high (> P 75 ), medium ( P 25 - P 75 ) and low (< P 25 ) level, according to the percentile of the questionnaire score. Multivariate logistic regression model was used to examine the associations of aggression and self-esteem with suicide risk, and to explore gender difference. Results: The gender differences were found in suicide risk, aggressive behavior and self-esteem( χ 2=80.21, 26.47, 26.51 , P <0.01). More girls reported suicide ideation, suicide plan and suicide attempt compared to girls( χ 2=33.03, 25.11, 15.71 , P <0.01). Compared with boys, the detection rate of suicide ideation, suicide plan and suicide attempt of girls were higher( P <0.01). The high aggressive behavior and low self-esteem was correlated with increased risk of suicide, and the interaction effects of aggressive behavior and self-esteem on suicide risk was found. The students with high aggressive behavior and low self-esteem had a higher suicide risk, the multiple adjusted odds ratio was 19.39 (95% CI =11.10-33.87). Gender difference was not found in the associations of aggressive behavior and self-esteem with suicide risk ( P >0.05). Conclusion Aggressive behavior and self-esteem are correlated with suicide risk in college students.

Objective: To investigate the relationship between childhood abuse and recent negative life events with suicidal ideation and attempt, and to provide reference for prevention and control of suicidal behaviors in middle school students. Methods: Stratified cluster sampling method was used to select 7 986 middle school students from Shenzhen, Nanchang and Shenyang as participants. Questionnaire survey was conducted to collect information on demographic indicators, childhood abuse, negative life events, suicidal ideation and suicide attempt, etc. Logistic regression was used to analyze the relationship between childhood abuse experience and negative life events with suicidal ideation and suicide attempt. Results: The prevalence of suicidal ideation and suicide attempt was 22.9% and 4.7%. After adjusted for confounding variables, with the increase of childhood abuse and negative life events, suicidal ideation and attempt in middle school students showed an increasing trend(P<0.05). Compared those with low level of childhood abuse and negative life events, students with high childhood abuse and high negative life events had a higher suicidal ideation and suicide attempt risk, the multiple adjusted odds ratio was 10.43 and 19.75(P<0.05). Conclusion Childhood abuse and negative life events are important risk factors affecting suicidal ideation and attempt in middle school students. Strategies to reduce childhood abuse and negative life events should be an integral component of targeted mental health interventions.

Objective:To investigate the efficacy of a SARS-CoV-2 recombinant protein vaccine as a booster dose.Methods:A new immunogen, namely RBD-sc-trimer, was designed by tandem repeating of single receptor binding domain (RBD) of SARS-CoV-2 spike (S) protein to mimic the trimeric form of RBD presented by the virus. The RBD-sc-trimer protein was expressed as a His-tagged fusion protein using a baculovirus expression system and purified by nickel affinity column. The purified protein was identified by Western blot. Its in vitro binding activity to human angiotensin converting enzyme 2 (hACE2) was analyzed by ELISA. The immunogenicity of RBD-sc-trimer as well as RBD proteins of other forms including RBD dimer (RBD-Fc), RBD monomer (RBD) and S protein trimer (S trimer) as a booster dose was evaluated in BALB/c mice. Results:In terms of both binding and neutralizing antibodies against SARS-CoV-2, RBD-sc-trimer showed an immunogenicity that was superior to that of RBD-Fc and RBD and close to the level of S trimer. The antibody response induced by RBD-sc-trimer was characterized as Th1-biased. Moreover, it displayed a stronger cross-neutralization activity against SARS-CoV-2 Beta, Delta and Omicron variants. The titer of neutralizing antibody against Omicron induced by RBD-sc-trimer only decreased by 9.1 folds relative to the prototype strain, while the antibody response induced by RBD-Fc and S trimer decreased by 68.4 and 70.8 folds, respectively.Conclusions:The recombinant protein, RBD-sc-trimer, which was capable of eliciting stronger humoral response in mice as a booster dose and showed the superiority in raising cross-reactive antibodies against SARS-CoV-2 variants over non-trimeric RBD forms, should be considered as an optimal immunogen for the development of more effective SARS-CoV-2 vaccines.

Objective: The aim of this study was to describe the distribution of neck-shoulder symptoms among middle school students, and to explore its influence factors. Methods: A cross-sectional survey was conducted on 24 middle schools in Shenyang, Zhengzhou and Shenzhen by purposive sampling method. In each middle school, 3 to 4 classes were selected from each grade all the students in the selected class would be recruited to the survey to investigate the demographic characteristics, neck-shoulder symptoms, physical exercise time, academic stress, screen behavior, sedentary behavior and other information by questionnaire. A total of 10 566 questionnaires were issued and 10 270 valid questionnaires were withdrawn. The prevalence of neck-shoulder symptoms among students were compared by different characteristics. Logistic regression models were applied to examine influencing factors associated with neck-shoulder symptoms. Results: The prevalence of neck-shoulder symptoms among middle school students was 19.2% (1 968/10 270), while it was 22.6% (1 137/5 039) among girls and 15.9% (831/5 231) among boys; the difference showed statistical significance (P<0.001). The prevalence of neck-shoulder symptoms was separately 13.3% (253/1 901) in seventh grade, 16.8% (326/1 942) in eighth grade, 18.5% (299/1 617) in ninth grade, 21.8% (417/1 915) in sophomore, 21.4% (345/1 611) in junior, 25.5% (328/1 284) in senior; the difference showed statistical significance (P<0.001). The multivariate logistic regression analysis showed that in the last 3 months, students who always playing mobile phone ≥40 min continuously (OR=4.66, 95%CI: 3.95-5.49), watching TV ≥40 min continuously (OR=4.01, 95%CI: 3.39-4.73), using computer ≥40 min continuously (OR=3.61, 95%CI: 3.09-4.23), doing homework ≥60 min continuously (OR=3.25, 95%CI: 2.79-3.79), the average daily sitting time ≥10 h (OR=4.95, 95%CI: 4.25-5.77), and always sitting ≥90 min continuously (OR=5.18, 95%CI: 4.42-6.06) were risk factors of neck-shoulder symptoms. Conclusion The prevalence of neck-shoulder symptoms was high among middle school students in China, especially girls in senior grades. Long time, high frequency video behaviors and sedentary behaviors were related to the occurrence of neck-shoulder symptoms among middle school students.

Objective: To compare the efficacy and safety of endoscopic submucosal dissection(ESD) and surgery in the treatment of early gastric cancer. Methods: Clinical data of patients with early gastric cancer who received ESD or surgery in Beijing Friendship Hospital from June 2012 to May 2018 were collected. Complete resection rate, complication incidence, hospital stay and expenses between the two groups were compared. Results: There was no significant difference between two groups in complete resection rate[95.7%(245/256) VS 99.0%(97/98), P=0.191], or the complication incidence [5.9%(15/256) VS 8.2%(8/98), P=0.471]. Hospital stay was shorter in the ESD group than that in the surgery group(11.5±3.7 d VS 19.4±13.0 d, P=0.000). Expenses were less in the ESD group than those in the surgery group (27 383.1±10 143.0 yuan VS 78 004.3±79 027.8 yuan, P=0.000). Conclusion The efficacy and safety of ESD are comparable with surgery in the treatment of early gastric cancer, but ESD is superior to surgery in hospital stay and expenses.

Objective: To investigate the risk factors of operation time of endoscopic submucosal dissection (ESD) for superficial gastric lesions. Methods: Clinicopathologic data of 193 patients (195 lesions) diagnosed with early gastric cancer preoperatively who received ESD in Beijing Friendship Hospital from January 2015 to December 2017 were retrospectively collected, including basic information (age, gender, body mass index, comorbidities), lesion characteristics (size, location, morphology), the operators′ experience of ESD, operation time, and postoperative pathology, etc. Univariate analysis was performed to find the risk factors of ESD operation time, and logistic regression analysis was performed on the factors with statistical differences in univariate analysis to find the independent risk factors of ESD operation time over 120 min. Results: The mean age of the patients was 63.34±9.11 years. The median time of ESD operation was 120.00 (95.00, 165.00) min and the median size of the lesions was 1.50 (1.00, 2.38) cm. Early gastric cancer was diagnosed by postoperative pathology in 164 lesions (84.10%), among which 162 lesions (98.78%) achieved en bloc resection, and 148 lesions (90.24%) achieved curative resection. The gender (P=0.018), location(P<0.001) and size (r=0.209, P=0.007) were risk factors of the operation time by univariate analysis, while age, body mass index, American Society of Anesthesiologists (ASA) grade, roughness of lesion surface, presence or absence of white moss and ulcer, depth of lesion invasion, operative period, gross shape of lesion, degree of differentiation, and experience of operator were not associated with operation time (all P>0.05). Multivariate analysis showed that the lesion located in cardia/fundus of stomach (OR=5.656, 95%CI: 2.291-13.964, P<0.001), body of stomach (OR=2.667, 95%CI: 1.048-6.785, P=0.040) and >2 cm in size (OR=2.761, 95%CI: 1.229-6.205, P=0.014) were independent risk factors for the operation time longer than 120 min. Conclusion Lesions located in the cardia/fundus, body of stomach and >2 cm in size are independent risk factors for long operation time of ESD.