ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.

OBJECTIVE To evaluate the efficacy， safety and economics of the centrally procured generic versus original esomeprazole in the treatment of acute non-variceal upper gastrointestinal bleeding （ANVUGIB）. METHODS A retrospective collection of real-world clinical data was conducted for ANVUGIB patients who received treatment at Shenzhen People’s Hospital and University of Hong Kong-Shenzhen Hospital from January 2018 to March 2024. Patients were divided into imported original drug group （original drug group， 221 cases） and centrally procured generic drug group （generic drug group， 75 cases） according to the types of drug used. Propensity score matching （PSM） was performed at a ratio of 3∶1 to compare the clinical efficacy， safety and economics between the two groups. RESULTS Totally 241 patients were included after PSM， with 170 in the original drug group and 71 in the generic drug group. There were no significant differences between the two groups in terms of rebleeding rate， rate of second endoscopic intervention， blood transfusion rate， length of hospital stay， mortality due to gastrointestinal bleeding， 30-day readmission due to rebleeding， and overall survival rate （P＞0.05）. The incidence of adverse events among all patients in both groups also showed no statistically significant difference （P＞0.05）； furthermore， the adverse events reported by the respective hospitals to the National Center for ADR Monitoring were comparable between the two groups. After PSM， the median total drug cost and high-dose esomeprazole cost in the generic drug group were significantly lower than those in the original drug group， while the median nursing fee and bed fee were significantly higher than those in the original drug group （P＜0.05）. There was no statistically significant difference between the two groups in terms of median total hospitalization expenses， total treatment costs， laboratory fees， examination fees， material costs， or consultation fees （P＞0.05）. CONCLUSIONS The clinical efficacy and safety of centrally procured generic esomeprazole in the treatment of ANVUGIB are comparable to those of the original drug， and it is more economical.

Aim To design and synthesize a series of phenylacetamide derivatives with different substituted phenylacetic acid as raw materials,and to investigate the protective effects of the compound on the damage of pancreatic β cells induced by palmitate acid(PA).Methods Min6 cells were cultured and divided into B blank control group,PA treatment group and PA+compounds group.The viability of Min6 cells was de-tected by CCK-8.The protein expressions of TXNIP and NLRP3 were observed by Western blot.MDA con-tent and SOD activity were detected by MDA and SOD kit.The insulin secretion of Min6 islet cells was meas-ured with insulin ELISA kit.Results A total of 10 phenylacetamide derivatives were designed and synthe-sized.Their structures were confirmed by 1H NMR and ESI-MS.Pharmacological activity study showed that most of the compounds had protective effects on islet βcells,among which LY-6 and LY-8 had stronger pro-tective effects than PA model group,with the cell via-bility of 61.4％,and LY-6 had the highest cell activi-ty,reaching to 104.9％.Compared with PA group,the protein expression of TXNIP and NLRP3 decreased in LY-6 and LY-8 groups,MDA content decreased and SOD activity increased,and insulin secretion of Min6 cell increased.Conclusions LY-6 and LY-8 inhibit TXNIP expression and decrease the activation of NL-RP3 inflammasome,and decrease the production of MDA and increase SOD activity,and thus reducing is-let β cells apoptosis and increasing insulin secretion.Therefore,the compound LY-6 could serve as a poten-tial anti-diabetic new chemical entity.

Aim To investigate the role and mecha-nism of CXC chemokine receptor 3(CXCR3)in hepa-toblastoma(HB).Methods The expression of CX-CR3 was detected by immunohistochemical and West-ern blot in 16 cases of HB tissue and adjacent normal liver tissue.The HB cells(Huh-6 and HepT1)were transfected with Con-shRNA,CXCR3-shRNA1,and CXCR3-shRNA2,respectively,and then divided into the Con-shRNA group,CXCR3-shRNA1 group,and CXCR3-shRNA2 group.Cell proliferation was detected by CCK-8 assay and EdU staining.Cell migration and invasion were detected by scratch and Transwell as-says.The expressions of β-catenin,c-Myc,cyclin D1,MMP-7 and MMP-9 were detected by Western blot.The tumor formation and tumor volume in each group were assessed using nude mouse xenograft tumor model,while the expressions of MMP-9 and Ki67 in tumor tissue were examined by immunohistochemistry.Results The expression of CXCR3 was up-regulated in HB tissue(P＜0.01).Compared to the Con-shR-NA group,the viability,proliferation,migration and invasion of Huh-6 and HepT1 cells in the CXCR3-shR-NA1 and CXCR3-shRNA2 groups were reduced(P＜0.01),the expressions of the Wnt/β-catenin signaling pathway related proteins were attenuated(P＜0.01),the tumor grew slowly and the volume was significantly reduced(P＜0.01),and the expressions of MMP-9 and Ki67 in tumor tissue decreased(P＜0.01).Con-clusions Downregulation of CXCR3 hinders the pro-liferation and migration of HB cells,potentially as-cribed to the attenuation of Wnt/β-catenin signaling regulation.

OBJECTIVE To establish a mouse model of diabetes mellitus(DM)combined with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection to investigate the important pathophysiological changes in the development of DM combined with SARS-CoV-2 infection.METHODS Wild-type(WT)mice and transgenic mice expressing the human angiotensin-converting enzyme 2 receptor driven by the cytokeratin-18 gene promoter(K18-hACE2)were randomly divided into the control group,DM group,SARS-CoV-2 spike protein(S)infection group and DM combined with S protein infection group,with 10 to 12 mice in each group.All the mice were induced by 10 weeks of high-fat diet combined with 40 mg·kg-1 streptozotocin(STZ)for 3 days by ip,except those in the control group or S protein infection group.The control group was given the same volume of 0.1 mol·L-1 sodium citrate buffer.Mice in the S protein infection group and DM+S protein infection group were additionally given 50 μL mixture of 15 μg SARS-CoV-2 spike protein and 1 g·L-1 polyinosinic-polycytidylic acid(poly[I:C])via intranasal drops,while the control group was given an equal volume of sterile water.The glucose tolerance level and pancreatic islet β cell function of mice were evaluated via oral glucose tolerance test at the 6th week of high-fat feeding and 1 week after the administration of STZ by ip.From the 6th week of high-fat feeding to 2 weeks after the administration of STZ,the random blood glucose and fasting blood glucose of mice were measured by a blood glucose meter.Blood samples were taken from subman-dibular veins of 3 mice in each group at 24,48 and 120 h after S protein infection,and lung tissues were taken after euthanization.The pathological changes of lungs of DM mice before and after S protein infection were observed by HE staining.Except for the DM group,blood samples were collected before S protein infection and at 6,24,48,72 and 120 h after infection.The levels of plasma interleukin 1β(IL-1β),IL-2,IL-6,IL-10,IL-17,interferon gamma-induced protein 10(IP-10),interferon γ(IFN-γ),tumor necrosis factor α(TNF-α),monocyte chemotactic protein-1(MCP-1)and granulocyte-colony stimulating factor(G-CSF)were detected by Luminex.The plasma levels of heparan sulfate(HS)were measured by enzyme-linked immunosorbent assay.The levels of cytokines and HS were correlated with the degree of pathological damage by Spearman correlation analysis.RESULTS STZ and high-fat diet could induce DM-like expression in mice,and the random blood glucose(P<0.01)and fasting blood glucose(P<0.05)after 1 week in the hACE2-DM group were significantly higher than in the WT-DM group,and the degree of islet function damage in hACE2-DM mice was significantly higher than that of WT-DM mice(P<0.05).Compared with the DM group,the DM+S group showed more severe pulmonary pathological changes after S protein infection,accompanied by a large number of inflammatory infiltrations and thickening of lung interstitial.Compared with the control group,the levels of pro-inflammatory cytokines G-CSF,IL-6 and IP-10 in the plasma of the WT-S group were significantly increased at 6 h after S pro-tein infection(P<0.01),and those of pro-inflammatory cytokine IL-17 and anti-inflammatory cytokine IL-10 were significantly increased at 24 h after S protein infection(P<0.05).Compared with the control group,the plasma levels of pro-inflammatory cytokines IL-1β,IL-6,TNF-α,MCP-1,G-CSF and IP-10 in the hACE2-S group were significantly increased at 6 h after S protein infection(P<0.05,P<0.01).IL-17 was significantly increased at 24 h and 6 h after S protein infection in the WT-DM+S group and hACE2-DM+S group,respectively(P<0.01,P<0.05).In the hACE2-DM+S group,IFN-γ and IL-1β were signifi-cantly increased in delay to 48 h(P<0.05,P<0.01),and MCP-1 was significantly increased in delay to 72h(P<0.05).Compared with the control group,the level of HS in the plasma of the WT-S group increased significantly(P<0.05,P<0.01)at 6 h and 24 h after S protein infection,but began to decrease at 48 h.At the same time,compared with the WT-S group,the HS level in the WT-DM+S group was slightly increased at 6 h after infection and decreased at 24 h.Compared with the control group,the HS level in the hACE2-S group was significantly increased at 24 h(P<0.01),as was the case with the WT-S group 24 h,48 h and 120 h after S protein infection.At 6 h,24 h and 48 h after S protein infection,the plasma HS level of the hACE2-DM+S group was significantly increased(P<0.01,P<0.05),and the duration of the increase was longer than in the hACE2-S group.Moreover,the levels of IL-1β,IL-10,MCP-1,IP-10,G-CSF and HS in plasma were positively correlated with the degree of lung dam-age in the DM+S group.CONCLUSION In this study,the mouse model of diabetes combined with SARS-CoV-2 spike protein infection has mimicked part of the pathophysiological features of clinical patients,mainly manifested as blunted immune response and elevated HS levels with longer duration to infection alone.IL-1β,IL-10,MCP-1,IP-10,G-CSF and HS may keep track of the course of disease in patients with diabetes combined with SARS-CoV-2 infection.

Objective To investigate the role and mechanism of miR-519d in brain metastasis(BM)of non-small cell lung cancer(NSCLC).Methods RT-PCR was used to detect the expression of miR-519d in normal lung tissues adjacent to cancer,NSCLC lung tissues,NSCLC brain tissues in NSCLC patients with or without BM,human NSCLC cell lines(SK-MES-1,NCI-H226,NCI-H1299,and NCL-H820),normal human bronchial epithelial cells(HBECs),human brain microvascular endothelial cells(HBMECs),and normal human astrocytes(NHA).NSCLC cell line NCI-H1299 was transfected with either miR-519d overexpression lentivirus(OE-miR-519d-LV)or empty vector lentivirus(NC-LV),and set as the OE-miR-519d-LV group and the NC-LV group;cells co-transfected with OE-miR-519d-LV and pcDNA3.1-HER3 were designated as the OE-miR-519d-LV+pcDNA3.1-HER3 group.The cells of the OE-miR-519d-LV group and the NC-LV group were injected intracardially into nude mice to establish an animal model of NSCLC with BM,and the mice were divided into the Ctrl group and the miR-519d group based on the injected cells.Bioluminescence imaging was used to observe NCI-H1299 cell metastasis in the brain of mice.The CCK-8 assay was used to determine the proliferation of NCI-H1299 cells in the OE-miR-519d-LV group and the NC-LV group.An in vitro blood-brain barrier(BBB)model was established using HBMECs and NHA-coated Transwell chambers,and the transendothelial migration ability of NCI-H1299 cells was detected.Western blot was used to detect the expression of epithelial-mesenchymal transition(EMT)-related proteins of MMP-2,MMP-9,E-cadherin,N-cadherin,and Vimentin in each group.Bioinformatics analysis was used to identify the potential binding sites between miR-519d and HER3,and their targeted regulatory relationship was validated by dual-luciferase gene reporter assays.Results Compared with the normal lung tissues adjacent to cancer,miR-519d expression was reduced in the NSCLC lung tissues and NSCLC brain tissues(P<0.05);miR-519d expression was lower in NSCLC brain tissues compared with the NSCLC lung tissues(P<0.05).Compared with HBECs,miR-519d expression was reduced in NSCLC cell lines(P<0.05),with lower levels in NCI-H1299,NCI-H226,and NCL-H820 cells compared with SK-MES-1 cells(P<0.05).Nude mice in the miR-519d group had a lower incidence of BM and longer survival compared with those in the Ctrl group,with statistically significant differences(P<0.05).Compared with the NC-LV group,NCI-H1299 cells in the OE-miR-519d-LV group showed decreases in the proliferation viability,transendo-thelial migration ability,and protein expression of MMP-2,MMP-9,N-cadherin,and Vimentin(P<0.05),and an increase in the protein expression of E-cadherin(P<0.05).miR-519d had a targeted regulatory effect on HER3 protein expression.Compared with the OE-miR-519d-LV group,the migration ability of cells in the OE-miR-519d-LV+pcDNA3.1-HRE3 group was increased(P<0.05),the protein expression of MMP-2,MMP-9,N-cadherin and Vimentin was increased(P<0.05),and the expression of E-cadherin was decreased(P<0.05).Conclusion miR-519d expression is reduced in NSCLC with BM,and its upregulation can inhibit the BM of NSCLC by targeting HER3.

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 investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.

Objective To examine the changing antimicrobial resistance profile of Enterobacter spp.isolates in 53 hospitals across China from 2015 t0 2021.Methods The clinical isolates of Enterobacter spp.were collected from 53 hospitals across China during 2015-2021 and tested for antimicrobial susceptibility using Kirby-Bauer method or automated testing systems according to the CHINET unified protocol.The results were interpreted according to the breakpoints issued by the Clinical & Laboratory Standards Institute(CLSI)in 2021(M100 31st edition)and analyzed with WHONET 5.6 software.Results A total of 37 966 Enterobacter strains were isolated from 2015 to 2021.The proportion of Enterobacter isolates among all clinical isolates showed a fluctuating trend over the 7-year period,overall 2.5％in all clinical isolates amd 5.7％in Enterobacterale strains.The most frequently isolated Enterobacter species was Enterobacter cloacae,accounting for 93.7％(35 571/37 966).The strains were mainly isolated from respiratory specimens(44.4±4.6)％,followed by secretions/pus(16.4±2.3)％and urine(16.0±0.9)％.The strains from respiratory samples decreased slightly,while those from sterile body fluids increased over the 7-year period.The Enterobacter strains were mainly isolated from inpatients(92.9％),and only(7.1±0.8)％of the strains were isolated from outpatients and emergency patients.The patients in surgical wards contributed the highest number of isolates(24.4±2.9)％compared to the inpatients in any other departement.Overall,≤ 7.9％of the E.cloacae strains were resistant to amikacin,tigecycline,polymyxin B,imipenem or meropenem,while ≤5.6％of the Enterobacter asburiae strains were resistant to these antimicrobial agents.E.asburiae showed higher resistance rate to polymyxin B than E.cloacae(19.7％vs 3.9％).Overall,≤8.1％of the Enterobacter gergoviae strains were resistant to tigecycline,amikacin,meropenem,or imipenem,while 10.5％of these strains were resistant to polycolistin B.The overall prevalence of carbapenem-resistant Enterobacter was 10.0％over the 7-year period,but showing an upward trend.The resistance profiles of Enterobacter isolates varied with the department from which they were isolated and whether the patient is an adult or a child.The prevalence of carbapenem-resistant E.cloacae was the highest in the E.cloacae isolates from ICU patients.Conclusions The results of the CHINET Antimicrobial Resistance Surveillance Program indicate that the proportion of Enterobacter strains in all clinical isolates fluctuates slightly over the 7-year period from 2015 to 2021.The Enterobacter strains showed increasing resistance to multiple antimicrobial drugs,especially carbapenems over the 7-year period.