Objective To analyze the biomechanical characteristics of the landing movements of com-petitive aerobics athletes,compare the laterality between their dominant and non-dominant limbs,and to explore the primary factors influencing landing stability.Methods Taking 26 female aerobics athletes in universities as the research objects,their kinematics and kinetics data of double-leg vertical land-ing with the height of 40 cm were simultaneously recorded.A comparison was made between the two limbs in terms of joint angles at initial contact,range of motion(ROM)of joint,ground reaction force(GRF),load-rate,the displacement and envelope area of the center of pressure(COP).The symmetry index(SI),reflecting laterality,was computed,and a multiple stepwise regression analysis was conduct-ed to examine the correlation between parameter asymmetry and COP envelope area.Results Compared with the non-dominant limbs,the dominant limbs had significantly greater knee external rotation and hip abduction angle at initial contact(P<0.05),significantly greater ROM of the ankle and hip flexion-extension and hip adduction-abduction,and smaller ROM of ankle rotation during landing(P<0.05).Moreover,the peak knee extension moment of the dominant limbs was significantly higher than the non-dominant limbs(P<0.01).The SI of vertical load rate and peak knee extension moment were signif-icantly positively correlated with the COP envelope area(P<0.05).In addition,the SI of vertical load rate,peak knee extension moment and knee rotation angle could explain 83.6%of the difference in the COP envelope area.Conclusion There is laterality between the dominant and non-dominant limb of competitive aerobics athletes during landing:the greater laterality of the load rate and peak knee ex-tension moment,the worse the landing stability.Furthermore,the SI of vertical load rate,peak knee extension moment,and knee rotation angle can be used as predictors of the landing stability.

Objective: To investigate the change in intestinal flora in Mongolian students with anxiety,so as to provide basis for exploring the relationship between flora and secretion expression in vivo. Methods: The Self rating Anxiety Scale(SAS)was used to assess anxiety in medical college students; then a semi structured interview was administered. Fecal samples that met the inclusion criteria were collected and divided into anxiety (SAS score≥50) and control groups (no anxiety, SAS score<50) according to the standard score of SAS. Samples provided by Mongolian female students were selected from each group. The total bacterial DNA was extracted from the fecal samples for PCR amplification and NovaSeq 2x250bp high throughput sequencing was performed for the V3- V4 region of 16S rDNA gene to obtain the biological information of the intestinal flora. The intergroup OTU, structural diversity, significant difference, and LEfSe analyses were performed with information mining of the literature think tanks. Results: Anxiety existed in 23.86% of the Mongolian students,and 16.96% of the Han people. A Chi square test showed no significant difference in detection of anxiety between Mongolian and Han college students ( P =0.07). Analysis of the alpha diversity index showed that the Shannon index, Simpson index, Chao1 index, and Observed species did not differed significantly between the two groups( t =8.0， 9.0 ，6.0，6.5). The difference in abundance of some bacteria was significant at the Class, Order, Family, and Genus levels between the two groups( t =-2.26-2.57，-5.08-3.58，-2.65-2.09， P <0.05). Conclusion The alpha diversity index showed that there was no significant difference in the abundance and diversity of intestinal flora between the two groups. While there were significant differences at different classification levels, the results suggest that the structure of intestinal flora can change in students with anxiety.

Objective:To explore the association between weight change from age 20 to middle age and diabetes risk.Methods:A total of 10 104 residents over 40 years old were recruited in Guangzhou. The final analysis data set is a cohort of 6 272 patients from the REACTION study. Quartile of weight changes from age 20 to middle-age was used as an independent variable to explore its association with newly diagnosed diabetes. Simple and multivariable logistic regression analysis were used to calculate OR and 95% CI. Results:The prevalence of newly diagnosed diabetes in study cohort was 15.7%. Weight changes from age 20 to middle-age was significantly higher in diabetes group( P<0.001). Logistic regression analysis found in general population and overweight people [24.0≤body mass index(BMI)<28.0 kg/m 2], after adjusting for gender, age, educational level, family history of diabetes, drinking, SBP, waist circumference, cholesterol, high-density lipoprotein-cholesterol(HDL-C), TG, ALT, AST, the risk of diabetes increased in line with the magnitude of weight change( P=0.081). While in group of lean, normal and obese adult, no significant association has been found. Conclusion:The risk of diabetes increased with weight change in general population and overweight people, indicating that weight change in adults after age of 20 was positively associated with diabetes. It is suggested the importance of weight management in the prevention of dialetes.

[Abstract] Objective: Elevated levels of soluble PD-L1 (sPD-L1) are associated with worse prognosis of renal cell carcinoma and multiple myeloma. However, the regulatory roles and functions of sPD-L1 in advanced melanoma are not fully understood. This study was designed to evaluate the association between circulating sPD-L1 concentrations and prognosis of patients with advanced acral or mucosal melanoma. Methods: A total of 102 untreated patients with advanced acral and mucosal melanoma admitted to Peking University Cancer Hospital between January 2012 and December 2015 were enrolled in this study. In the meanwhile, peripheral blood samples were obtained from 40 healthy donors. Circulating sPD-L1 concentrations were determined using an enzyme-linked immunosorbent assay. Results: The advanced melanoma cohort included 58 acral melanoma patients and 44 mucosal melanoma patients. The pre-treatment concentration of sPD-L1 (2.91±2.23 ng/ml) in plasma of patients group was elevated as compared with that in healthy donors (0.59 ng/ml). The concentration of sPD-L1 in serum was significantly upregulated in 39/102 (38.2%) patients and significantly associated with increased LDH level (P=0.021) and number of Tregs (P=0.017). The overall survival rates of patients with high or low concentrations of sPD-L1 were statistically different (8.5 months [high level] vs 11.6 months [low level], P=0.022). Conclusion: sPD-L1 concentration is elevated in patients with advanced acral or mucosal melanoma, which may play an important role in predicting prognosis.

[Abstract] Objective: To explore the expression patterns of melanoma lineage antigens and nuclear antigen Ki-67 and their correlations with survival in melanoma patients. Methods: A retrospective analysis was conducted to analyze the pathological data of melanoma patients treated at the Department of Melanoma, Peking University Cancer Hospital from February 2008 to August 2020, mainly including the expression patterns of melanoma lineage antigens (S-100, HMB-45, Melan-A) and Ki-67, demographics, clinical features and survival. The correlation between expression patterns of melanoma lineage antigens, Ki-67 and melanoma-specific survival (MSS) was analyzed. Results: In total, 603 patients were included in this study. The median follow-up time was 47.4 months. The positive rates of S-100, HMB, and Melan-A were 92.8%, 92.1% and 90.0%, respectively. The percentages of patients with melanoma lineage antigen scores (S-100, HMB-45 and Melan-A was scored each, as 1 when positive and 0 when negative) of 0, 1, 2, and 3 were 0.5%, 5.0%, 15.6%, and 78.8%, respectively. The percentages of patients with Ki-67 scores of 0, 1, 2, and 3 were 43.0%, 36.3%, 16.3%, and 4.5%, respectively. Ki-67 was highly expressed in mucosal and progressive melanomas. In a multivariate analysis, Ki-67 expression was an independent prognostic factor for poorer MSS (HR=1.506, 95%CI: 1.248-1.818, P<0.001) as the incidence of MSS event increased by 50% per 25% increase in Ki-67 expression, whereas there was no statistical correlation between melanoma lineage antigen expression and MSS (HR=0.991, 95%CI: 0.759-1.293, P=0.94). Conclusion: High expressions melanoma lineage antigens are ubiquitous in melanoma tissues, and Ki-67 is an independent prognostic factor for MSS.

[摘 要] 目的：本研究旨在评估白蛋白紫杉醇+卡铂联合抗血管生成药物（nab-paclitaxel, carboplatin, antiangiogenic drug, NCA）方案用于既往治疗失败的晚期黑色素瘤患者的疗效和安全性。方法：收集2012年4月1日至2019年5月31日在北京大学肿瘤医院肾癌黑色素瘤科住院的黑色素瘤患者，回顾性分析NCA方案在既往治疗失败后的不可切除Ⅲ c期和Ⅳ期黑色素瘤患者中的疗效和安全性。主要终点指标为无进展生存期（PFS），次要指标为客观缓解率（ORR）、总生存期（OS）、疾病控制率（DCR）和不良反应。根据使用的抗血管药物分为恩度治疗组（n=73）和贝伐珠单抗治疗组（n=103），采用倾向性评分匹配以均衡不同抗血管生成药物组间基线变量的差异。结果：共计176例患者被纳入本项分析中。所有患者中位年龄51岁（范围为18~78岁）。Ⅳ期患者占97%，50%的患者LDH水平高于正常值，28%的患者存在肝转移。既往治疗线数占比分别为1线57%、2线33%、3~4线10%。所有患者的中位PFS为3.8个月（95%CI：3.0~4.6），中位OS为10.5个月（95%CI： 8.9~12.1）。2例患者获得完全缓解，9例患者获得部分缓解，全组的ORR为6%，DCR达70%。恩度治疗组和贝伐珠单抗治疗组的中位PFS分别为4.7个月（95%CI：3.5~5.9）和3.4个月（95%CI：3.0~4.6），两组中位OS分别为12.2个月（95% CI：11.1~13.2）和9.1个月（95%CI： 7.8~10.4）。对所有患者的年龄、性别、既往治疗线数和LDH水平进行倾向性评分匹配，贝伐珠单抗和恩度治疗组间PFS和OS差异无统计学意义。常见的不良反应包括脱发、周围神经病变、中性粒细胞减少、疲劳和恶心。26名（15%）患者由于不良反应停止了治疗。结论：白蛋白紫杉醇+卡铂联合抗血管生成药物对既往治疗失败的晚期黑色素瘤患者具有一定的疗效，不良反应可耐受。

Objective: To explore effect of intensive intervention for improving the referral rate of children with visual refractive disorders, and to provide a reference for myopia prevention and control of children and adolescents. Methods: A total of 4 464 preschool children were selected from Zhuanqiao county, Minghang district in Shanghai for the eyesight investigation during April to June in 2019. Stratified random cluster sampling method was used to divide 1 724 children into intervention group and (896) control group (828) depending on the type of kindergartens. The intervention group was provied with an intensive intervention, including children s vision health assessment, parental self management guidance for children s eye care, and community based eye care services, while the control group carried out routine intervention measures. Results: In 2019, the incidence of visual and primary refractive screen abnormalities in preschoolers of Zhuanqiao community was 38.62%. The incidence of naked eye vision abnormalities was 4.40%, the incidence of myopia risk group, hyperopia risk group and astigmatism risk group was 37.10%, 2.20%, and 6.10 %, respectively. After the intervention, the referral rate of the intervention group (68.75%) was significantly higher than that of the control group (17.15%)( χ 2=465.09, P <0.01). The differences between two groups were statistically significant in choosing the hospital for treatment ( χ 2=10.01, 51.51, 15.40, 27.79, 19.96, 24.24, P <0.01). Conclusion The vision and refractive status of preschoolers worths further attention. Intensive intervention can improve the referral rate for children with screened vision abnormalities, which facilitates the prevention and early diagnosis of vision problems among preschoolers.

Objective:To explore the prognostic value of PD-L1 expression level in patients with metastatic renal cell carcinoma (mRCC).Methods:The clinicopathological and survival data of patients with mRCC in our hospital from Jan 2014 to Apr 2016 were retrospectively analyzed including 46 males and 15 females. The median age of these patients was 56 years(range: 29-75 years), with 41 patients ≤60 years and 20 patients >60 years. The baseline data before the systemic therapy showed 36 patients(59.0%)had 1 metastatic organ and 25 patients (41.0%) had equal or more than 2 organs to be metastasized. Among them, 17 patients(27.9%)had lung metastasis and 54 patients(88.5%)had liver metastasis. Abnormal baseline LDH occurred in 4 patients and 52 patients had normal LDH. Favorite and intermediate risk patients categorized by MSKCC risk stratification accounted for 59.6%(34 patients)and 40.4%(23 patients), respectively. Six patients(9.8%)experienced distant metastasis at initial diagnosis, with 4 of them undergoing primary site resection, and the other 55 patients undergoing radical nephrectomy. PD-L1 expression was detected by the immunohistochemical staining method. PD-L1 staining rate ≥1% detected on the tumor cell membrane was defined as positive expression. The correlation between PD-L1 expression and clinicopathological characteristics were compared. Kaplan-Meier method and log-rank test were used to compare the differences about DFS and OS under different factors. Cox proportional hazards regression model is used for multivariable analysis of survival data.Results:The detailed pathological types of the 61 patients with renal cell carcinoma were classified as 53 clear cell carcinomas, 3 papillary carcinomas, 1 collecting duct carcinoma, 2 translocation renal cell carcinomas and 2 being unclassified. There were 4, 20, 19 and 9 patients categorized as WHO/ISUP nuclear grade 1, 2, 3 and 4, and 26, 12, 20 and 2 patients were categorized as T 1, T 2, T 3 and T 4 stage, respectively. Five patients had regional lymph node metastasis(N+), and the other 56 patients had no regional lymph node metastasis(N-). The numbers of patients categorized as stage Ⅰ, Ⅱ, Ⅲ and Ⅳ diseases according to TNM staging system were 20, 11, 21 and 8, respectively. The total PD-L1 positive rate was 24.6%(15/61). The corresponding PD-L1 expression rate of patients with WHO/ISUP nuclear grade 1-4 were 0(0 patient), 5.0%(1 patient), 31.6%(6 patients)and 44.4%(4 patients), respectively; With the increasing WHO/ISUP nuclear grade, the positive rate of PD-L1 gradually escalated with a linear correlation ( P=0.006). The PD-L1 expression of the normal and abnormal LDH group were 19.2%(10 patients)and 75.0%(3 patients), respectively, with significant difference( P=0.035). Univariate analysis of disease-free survival time(DFS)showed that the prognostic factors include PD-L1( P=0.045), age group( P=0.014), WHO/ISUP nuclear grade( P<0.001), T stage( P=0.015), N stage( P=0.026)and TNM stage( P=0.005). However multivariate analysis only suggested WHO/ISUP nuclear grade as the independent prognostic factors for DFS( HR=1.8, 95% CI 1.1-2.9, P=0.018). Either in univariate or multivariate analysis, PD-L1 was not a prognostic factor for overall survival (OS)of mRCC patients(univariate analysis: P=0.154; multivariate analysis: P=0.902). The independent prognostic factors of OS include WHO/ISUP nuclear grade( HR=3.0, 95% CI 1.1-8.0, P=0.033)and MSKCC risk stratification( HR=5.9, 95% CI 1.2-29.7, P=0.03). Conclusions:This study showed that the higher the WHO/ISUP nuclear grade of patients with mRCC, the higher the positive rate of PD-L1. PD-L1 expression was not the independent prognostic factor for DFS or OS of mRCC.

Objective:To evaluate the role of hippocampal histone deacetylases (HDACs) in perioperative neurocognitive disorders (PND) and the relationship with postsynaptic dense protein 95 (PSD95) in rats.Methods:Sixty clean-grade healthy male Sprague-Dawley rats, aged 10-14 weeks, weighing 250-280 g, were divided into 3 groups ( n=20 each) using a random number table method: control group (group C), surgery group (group S) and HDAC inhibitor MS-275 group (group MS-275). Exploratory laparotomy was performed under 3% sevoflurane anesthesia in group S. MS-275 10 mg/kg was intraperitoneally injected at 0.5 h before exploratory laparotomy in group MS-275.Morris water maze tests were performed on 1 day before surgery and 1, 3 and 7 days after surgery.Ten rats were sacrificed on 1 day after surgery, and hippocampal tissues were obtained for determination of the expression of HDAC1-3 and PSD95 protein and mRNA by Western blot and real-time polymerase chain reaction, respectively.The density of hippocampal neurons was determined by the Nissl staining. Results:Compared with group C, the postoperative escape latency was significantly prolonged, the number of crossing the original platform was decreased, the density of hippocampal neurons was decreased, the expression of HDAC2 protein and mRNA was up-regulated, and the expression of PSD95 protein and mRNA was down-regulated in group S ( P<0.05 or 0.01). Compared with group S, the postoperative escape latency was significantly shortened, the number of crossing the original platform was increased, the density of hippocampal neurons was increased, the expression of HDAC2 protein and mRNA was down-regulated, and the expression of PSD95 protein and mRNA was up-regulated in group MS-275 ( P<0.05 or 0.01). There was no significant difference in the expression of HDAC1 and HDAC3 protein and mRNA among the three groups ( P>0.05). Conclusion:HDAC2 is involved in the pathophysiological mechanism of PND by down-regulating the expression of PSD95 in rats.

Objective To certify that Chlamydia can spread from the genital tract to the gastrointestinal tract for long-lasting colonization.Methods Totally,120 female C57BL/6J mice aged 5-6 weeks were divided into 4 experimental groups to be inoculated with purified Chlamydia muridarum (C.muridarum) elementary bodies in the vagina (n =35),gastric area (n =30),anus and rectum (n =30),retro-orbital venous plexus (n =5) respectively.Moreover,corresponding negative groups inoculated with sucrose phosphate glutamate buffer (n =5) were set up for each experimental group.On days 3,7,and every 7 days,vaginal and rectal discharges were collected with swabs from the mice,and the number of live C muridarum orgnisms in exfoliated cells infected with C muridarum in the swabs was determined.Indirect immunofluorescence assay and quantitative PCR (qPCR) were performed to determine the number of live chlamydial organisms and the copy number of chlamydial genomes in the mouse genital tract (vagina,uterus,oviduct and ovary),gastrointestinal tract (stomach,small intestine,cecum,colon,rectum)and parenteral tissues (heart,liver,spleen,lung,kidney) on days 7,14,28,56 and 105 after the inoculation.The number of live chlamydial organisms and copy number of chlamydial genomes were transformed logarithmically with a base of 10.The degree of hydrosalpinx and inflammation in the genital tract,and histopathological changes of the gastrointestinal tract were observed.The infectivity and virulence of C.muridarum in the genital tract and gastrointestinal tract were evaluated in the intragastric inoculation group and intra-anal and intrarectal inoculation group on days 28 and 56 after the inoculation.Blood samples were obtained from the mouse caudal vein in the retro-orbital venous plexus inoculation group on days 3,5,7,10 and 14 after the inoculation,the number of live chlamydial organisms and the copy number of chlamydial genomes in the blood samples were determined,and chlamydial infectivity in the genital tract and gastrointestinal tract was evaluated on day 56.Results On day 7 after the inoculation in the vagina,both C.muridarum live organisms and genomes were detected in the genital tract,gastrointestinal tract and parenteral tissues of all the mice.The largest common logarithm of the number of C.muridarum inclusion forming units (IFU) was observed in the vagina (6.26 ± 0.56),with the common logarithm of the copy number of chlamydial genomes in the vagina being 7.30 ± 0.23,and the common logarithms of the number of Chlamydia IFU and genomic copy were 2.60 ± 1.95 and 4.87 ± 0.09 respectively in the rectum.On day 28,no live Chlamydia was detected in the heart,lung or other parenteral tissues,while live Chlamydia could be found in the genital tract and gastrointestinal tract.The common logarithms of the number of Chlamydia IFU and genomic copy were 3.47 ± 1.06 and 5.80 ± 1.49 respectively in the vagina,and 4.00 ±0.35 and 5.14 ± 0.81 respectively in the rectum.On day 56,live Chlamydia could only be detected in the gastrointestinal tract.On day 105,live Chlamydia and its genomes could be still detected in the gastrointestinal tract,and the common logarithms of the number of Chlamydia IFU and genomic copy could be up to 2.60 ± 0.65 and 4.29 ± 0.57 respectively in the rectum.On days 28 and 56 after the inoculation,both live Chlamydia and its genomes could be detected in the gastrointestinal tract of all the mice in the intragastric inoculation group and intra-anal and intrarectal inoculation group.Chlamydia could survive in the blood for about 14 days in the retro-orbital venous plexus inoculation group,and live Chlamydia was detected in anal-rectal swabs in all the mice on day 14.On day 56 after the intravaginal inoculation with C.muridarum,severe hydrosalpinx,chronic inflammation and oviduct dilation occurred in the genital tract of 5 mice,but there was no obvious infiltration of inflammatory cells in the gastrointestinal tract,and inflammatory pathological changes were not observed in the gastrointestinal tract of mice after inoculation with Chlamydia through other routes either.Conclusion The infection with Chlamydia in the genital tract can lead to systemic dissemination,and Chlamydia can be spread to the gastrointestinal tract,and colonize and survive in the gastrointestinal tract for a long time.