convalescents, and to screen for broad-spectrum neutralizing antibodies against the SARS-CoV-2 RBD. Methods Using biotinylated RBD as a molecular probe, flow cytometry was employed to perform single-cell sorting of B cells from peripheral blood mononuclear cells (PBMCs) of convalescents. The obtained B cells were lysed and subjected to reverse transcription, followed by nested PCR amplification of the heavy and light chains of antibodies was conducted using random primers. The amplified products were cloned into corresponding expression vectors, and the respective matched heavy-light chain plasmids were co-transfected into 293F cells for expression. Monoclonal antibodies were then purified using Protein A column chromatography. Neutralization experiments were conducted with the wild-type (WT) pseudovirus, and antibodies with IC50<0.1 μg/mL were selected for further testing of neutralizing breadth and potency against the wild-type (WT), Beta variant (B.1.351), Delta variant (B.1.617.2), and currently prevalent pseudovirus strains (XBB, BA.5, BF.7). Results A total of 21 RBD-specific monoclonal B cells were obtained from two recovered patients, resulting in the isolation of 13 pairs of antibody light/heavy chains. Nine antibodies were successfully expressed, with P1-A1, P1-B6, and P1-B9 exhibiting IC50 values below 0.1 μg/mL against the pseudovirus of the wild-type strain (WT). Specifically, P1-B6 effectively neutralized the wild-type strain (WT), Beta variant (B.1.351), and Delta variant (B.1.617.2), with IC50 values reaching 0.01 μg/mL. P1-B9 demonstrated effective neutralization against the wild-type strain (WT), Beta variant (B.1.351), Delta variant (B.1.617.2), and Gamma variant (P.1) pseudoviruses, with IC50 values of 0.42 μg/mL, 0.63 μg/mL, 0.28 μg/mL, and 2.50 μg/mL, respectively. Additionally, P1-B6 exhibited good neutralization against BA.5 and BF.7 pseudoviruses, with IC50 values of 0.06 μg/mL and 0.09 μg/mL, respectively. Conclusions Infection with the SARS-CoV-2 WT strain can induce the generation of neutralizing antibodies with broad-spectrum activity. Generating these broadly neutralizing antibodies does not require an excessively high somatic hypermutation. The obtained antibodies can be used as candidates for SARS-CoV-2 diagnosis and prevention.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective:To focus on the physical activity strategy to maintain the activity ability of the elderly in the community, comprehensively retrieve and integrate the best evidence, form practical suggestions with the goal of the transformation and practice of evidence, so as to provide scientific, reliable and up-to-date basis for the implementation of relevant evidence.Methods:According to the 6S pyramid model, the British Medical Journal (BMJ) Best Practice, UpToDate, DynaMed, World Health Organization, Chinese Medical Association, National Institute for Health and Care Excellence, Scottish Intercollegiate Guidelines Network, New Zealand Guidelines Group, PubMed, SinoMed and other databases were retrieved layer by layer from top to bottom. This study obtained all articles of evidence-based knowledge base resources, clinical practice guidelines, expert consensus, systematic review and other types related to physical activity strategies to maintain the activity ability of the elderly in the community from January 1, 2017 to March 1, 2022. According to the inclusion and exclusion criteria of the article, 2 to 4 researchers conducted independent methodological quality evaluation on different types of article according to the tool requirements, extracted and summarized the best evidence, and formed practical suggestions.Results:A total of 14 articles were included, including 2 evidence-based decision-making, 6 guidelines, 1 expert consensus, 3 systematic reviews, and 2 overviews of systematic review. Seven dimensions such as "overall advice, health benefits, diversified sports training, aerobic training, balance training, muscle strengthening/resistance training, flexibility training" and 22 best pieces of evidence were extracted and summarized, and practical suggestions were formed.Conclusions:Medical and nursing staff should adopt evidence-based methodological practical suggestions to provide management guidance and consultation for the maintenance of physical activity ability of the elderly in the community, so as to help the elderly to maintain physical activity ability and gain health benefits.

Objective:To establish an in vivo model of acute radiation esophagitis in Wistar rats based on a small animal precision radiotherapy platform (SARRP). Methods:Thirty-six Wistar rats were randomly divided into control group, 40, 60 and 75 Gy groups. Based on MRI images, the esophageal target area of rats was outlined and the radiotherapy plan was formulated. The rats were respectively irradiated with 0, 8, 12 and 15 Gy per day for 5 consecutive days. The changes of body weight, food intake, esophageal pathology and magnetic resonance imaging were observed.Results:The body weight of rats in 75 Gy group decreased significantly on the 6th day after irradiation (IR) ( P<0.05). The esophageal tissue of rats in each IR group was thicker than that in control ( F = 14.20, P < 0.05). HE staining showed that the formation rate of radiation-induced esophagitis in 40 Gy and 60 Gy groups were 4/5 and 5/5, respectively, mainly mild. In 75 Gy group, the incidence of radiation-induced esophagitis approached to 5/5, of which 3/5 was severe at 9 d post-IR. The pathological injury scores [ M( Q1, Q3)] of rats in each group were 0, 1.0 (0.5, 2.5), 1.0 (1.0, 2.5) and 4.0 (1.5, 6.0) on the 9th day after IR. There was significant difference between the 75 Gy group and the control group ( H=12.69, P<0.05). After dynamic monitoring of neck MRI images, it was found that the esophageal signal of rats in each IR group increased and widened at 9 d post-irradiation. Conclusions:The animal model of acute radiation-induced esophagitis in rats was successfully established based on a small animal precision radiotherapy platform combined with MRI. 75 Gy was the best irradiation dose and the 9th day was the best observation time point.

【Objective】 To conduct a retrospective study of the population characteristics, efficacy and influencing factors of rheumatoid arthritis (RA) patients who received iguratimod (IGU) treatment for at least 6 months from July 2015 to October 2020 and had more than 3 follow-up records. 【Methods】 In this study, 105 patients with RA were enrolled, and all the patients received IGU treatment for at least 6 months and were followed up three times. We observed their clinical manifestations before and after treatment, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), disease activity index (DAS28), rheumatoid factor (RF), anticyclic citrullinated peptide (ACPA), immunoglobulins (IgG, IgA, and IgM), lymphocyte subsets, and observed and recorded adverse reactions. 【Results】 The course of disease and the positive rate of ACPA were significantly lower in IGU group than in the group of IGU combined with (MTX) treatment (P<0.05). The DAS28-ESR of the patients in IGU group was significantly lower than that in the IGU+MTX treatment group and IGU+leflunomide (LEF) treatment group (P<0.05). After 6 months of continuous treatment, visual analogue scale/score (VAS), CRP and DAS28 (ESR/CRP) in IGU group were significantly reduced. As the treatment time was extended to one year, the above indicators further improved, and the number of joint swelling (SW) and the number of joint tenderness (TEN) also significantly improved. After one year’s continuous treatment, the incidence of adverse reactions in IGU group was 32.3%(10/31). 【Conclusion】 For RA patients with early onset, short-course, and antibody-negative, IGU is an effective therapeutic drug and a treatment option for RA patients with interstitial lung disease. IGU is well tolerated and is also an effective and a safe combination therapy option.

Objective: To analyze the effect of epigallocatechin-3-gallate (EGCG) in radiation induced esophagitis of model rabbit. Methods: Thirty male New Zealand rabbits were randomly divided into EGCG group, saline group, blank group. The rabbits in EGCG and saline groups were irradiated with 6 MV X-rays. The blank group did not receive radiation. After irradiation, rabbits were given with 440 μmol/L EGCG or saline three times a day in continuous 5 days. The scores of pathological changes of esophagus were observed by optical microscope.The serum levels of interleukine-1 beta (IL-1β), interleukine-6 (IL-6), transforming growth factor-β (TGF-β) and tumor necrosis factor-α (TNF-α) were detected by enzyme linked immunosorbent assay. The expression levels of 67KD laminin receptor (67LR) was detected by immunohistochemistry. Results: After treatment, the scores of pathological changes of esophagus in blank group, saline group, EGCG group were 0, 3.9±1.10 and 2.80±0.92, respectively. At different time points after drug treatment, the levels of serum inflammatory factors among three groups were significantly different (F=23.66-236.32, P<0.05). The expressions of 67LR in esophageal tissue of 3 groups were also significantly different (F=585.38, P<0.05). Conclusions EGCG reduced radiation-induced esophagitis in rabbits by decreasing the levels of serum inflammatory factors, which may be related to the expression of 67LR protein.

Objective: To explore the relationship between the vitamin D levels and lipid metabolism during second trimester. Methods: A total of 1 875 pregnant women who were in the second trimester and had antenatal care in 3 hospitals in Hefei of Anhui province from March 2015 to February 2018 were included. Baseline questionnaire survey was performed, and fasting venous blood samples were collected from the pregnant women to detect serum 25(OH)D, cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) levels. Cubic non-linear model and linear regression model were used to analyze the linear relationship between vitamin D levels and lipid metabolism indicators in the second trimester. Results: The vitamin D deficiency rate was 75.3% (1 412/1 875) in the pregnant women. The mean levels of lipid metabolism indicators TC, TG, HDL-C and LDL-C were (233.22±38.87), (226.24±83.88), (79.04±12.77), and (109.54±25.95) mg/dl respectively. Multivariate linear regression model results showed, compared with Q5 of the 25(OH)D, the TC and TG levels of Q1-Q4 groups significantly increased, and the LDL-C of Q1 and Q2 groups significantly increased. The highest difference between TC, TG and LDL-C was observed in Q1 group. (TC: β=16.88, 95%CI: 10.50-23.26; TG: β=34.92, 95%CI: 21.32-48.53; LDL-C: β=9.06, 95%CI: 4.77-13.35). No significant differences in HDL-C level among the 5 groups were observed. When stratified with vitamin D deficiency the results showed that, when 25(OH)D was <50 nmol/L, TC, TG and LDL-C levels decreased by 3.53 (95%CI: 1.30-5.75), 7.42 (95%CI: 2.41 to 12.44) and 2.08 mg/dl (95%CI: 0.60-3.57) along with a 10 nmol/L increase of 25(OH)D, the difference was statistically significant, and when 25(OH)D was ≥50 nmol/L, no significant correlation was found between 25(OH)D level and TC, TG and LDL-C levels. No significant relationship between 25(OH)D level and HDL-C level was observed regardless of vitamin D deficiency. Conclusions There was a nonlinear relationship between vitamin D levels and lipid metabolism indicators in the second trimester. There was a significant negative correlation between 25(OH)D level and lipid metabolism indicators only in the deficiency of vitamin D.

Objective: To construct Bayes discriminant function for clinical classification of common and severe Japanese encephalitis (JE) cases, and to identify cases accurately with quantitative indicators. Methods: Samples of confirmed common and severe JE cases reported by the epidemic surveillance system of Gansu Provincial Center for Disease Control and Prevention from 2005 to 2017 were collected. Non-conditional logistic regression analysis and Bayes stepwise discriminant analysis were used to screen meaningful clinical indicators, so as to construct and evaluate Bayes discriminant function. Results: There were 256 common JE cases and 257 severe JE cases. There were no significant differences in sex, age and occupation distributions between the two groups (P>0.05) and there was significant difference in case fatality rate (P<0.05). Non-conditional logistic regression analysis and Bayes stepwise discriminant analysis, combined with using related literature, to screen 11 clinical indicators for the construction of Bayes discriminant function. Interactive validation showed that the sensitivity of discriminant function was 71.48% (95%CI: 65.53%-76.93%) and the specificity was 73.93% (95%CI: 68.11%-79.19%). The area under ROC curve was 0.761 (95%CI: 0.720-0.803) and the total accuracy rate was 72.71%. Conclusion Bayes discriminant function can be used to identify common and severe JE cases more accurately, which is helpful for the reasonable treatment and good prognosis of JE patients.

From March 2015 to February 2018, 4 728 women aged 18 to 45 years old with single-pregnancy at the gestational age of 13 to 27 weeks in Hefei were recruited to analyze the trend of vitamin D status. The average levels of serum 25(OH)D in 2015, 2016 and 2017 were (43.22±18.41) nmol/L, (39.3±15.1) nmol/L and (36.6±17.0) nmol/L, and the prevalence of vitamin D deficiency were 69.5%, 77.6% and 81.4%, respectively. Compared with 2015, the levels of serum 25(OH)D in pregnant women in 2016 and 2017 decreased by 5.23 (95%CI: 4.10-6.35) nmol/L and 7.98 (95%CI: 6.77-9.19) nmol/L. The OR (95%CI) values for the risk of vitamin D deficiency were 1.88 (95%CI: 1.57-2.24) and 2.41 (95%CI: 1.98-2.93).

Objective To explore the relationship between different statuses of vitamin D and parathyroid hormone (PTH) during pregnancy with glucose metabolism and the risk of gestational diabetes mellitus (GDM). Methods A total of 4138 pregnant women who had antenatal care in 3 hospitals of Hefei from March 2015 to December 2017 were recruited during 21-24 weeks. Baseline questionnaires were performed and serum 25-hydroxyvitamin D [25(OH) D] and PTH levels were measured in fasting venous blood. Glucose tolerance tests were performed during 24 to 28 weeks. Multivariate linear regression model and multivariate logistic regression model were applied to analyze the differences of glucose metabolism index and GDM risk among pregnant women at different statusesof25(OH)DandPTH.Results Theaveragelevelof25(OH)Dinthesecondtrimesterwas(39.8±16.6) nmol/L, with the median PTH 10.7 (6.9, 16.7) ng/L and the detection rate of GDM 20.4％. Covariance analysis showed no statistically significant association of vitamin D and PTH levels with glucose metabolism indexes. Pregnant women with high PTH and vitamin D deficiency had higher 1h postprandial plasma glucose ( 1hPG) , the area under the glucose curve ( AUCglu ) levels, and GDM risk compared with pregnant women with middle/lower PTH and vitamin D deficiency ( control group, all P<0.05) , and higher PTH accompanied with vitamin D non-deficiency ( Group 2, all P<0.05) . However, significant changes in glucose metabolism indicators and GDM risk were not observed in low-level PTH-pregnant women with vitamin D deficiency ( group 1) and group 2 pregnant women compared with control group. Conclusion There is an interaction between vitamin D/PTH levels and glucose metabolism during pregnancy. Vitamin D deficiency with elevated PTH level is associated with abnormal glucose metabolism.