Aim To construct a model of vascular endothelial cell(EC)-specific gene knockout mice of tumor necrosis factor receptor-associated factor 2(Traf2)by using Cre-loxP technolo-gy,thus to provide basis for the research of vascular dysfunction-related diseases related to the regulation of vascular EC activity through TRAF2.Methods The Cre-loxP system was used to construct a mouse model with EC-specific knockout of Traf2 gene(Traf2flox/flox Tek-iCre+).The mouse genotype was identi-fied through PCR and gel electrophoresis.Primary vascular ECs were isolated from the mice using flow cytometry.The knockout efficiency of Traf2 in vascular ECs was validated by Western blot and immunofluorescence.The pathological changes in blood ves-sels and major organs of the mice were examined using hematox-ylin-eosin(HE)staining.The tube-forming ability of primary vascular EC was assessed using Matrigel tube formation.Results The knockout mice met the required genetic criteria.Flow cy-tometry results demonstrated the successful isolation of primary vascular EC,and TRAF2 expression in vascular EC of knockout mice was significantly reduced(P＜0.01).Histological results showed that TRAF2 expression in the vessel of knockout mice decreased,and the morphology had no significant changes in their blood vessels and major organs.The Matrigel tube forma-tion demonstrated that the tube-forming ability of primary vascu-lar EC from knockout mice was reduced.Conclusion Traf2 specific knockout mouse model in vascular ECs is successfully constructed,providing a reliable animal model for research into the regulatory mechanisms of TRAF2 on vascular ECs in vascular dysfunction related diseases.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective To study the clinical characteristics,imaging findings,pathological features,treatment methods,and prognosis of nasopharyngeal carcinoma in children.Methods The clinical data of 6 children(<18 years)with nasopharyngeal carcinoma admitted to the Department of Pediatrics,Beijing Tongren Hospital from March 2021 to February 2025 were retrospectively reviewed,and outcomes were followed up.Results All 6 patients were male.Age at onset ranged from 11 to 15 years,with a median of 12.5 years.The interval from onset to diagnosis was 1-6 months.The main clinical symptoms were cervical mass(4 cases,67%)and headache(3 cases,50%);some patients also had nasal congestion and rhinorrhea,epistaxis,or limited mouth opening.TNM staging was stage III in 4 cases and stage IVa in 2 cases.All patients had non-keratinizing undifferentiated nasopharyngeal carcinoma on pathology.Treatments included radiotherapy,chemotherapy,surgery,targeted therapy,and immunotherapy.By July 1,2025,after comprehensive treatment,5 patients(83%)achieved complete remission,and 1 patient(17%)experienced recurrence and progression and died.Conclusions Comprehensive treatment based on combined radiotherapy and chemotherapy is the mainstay for childhood nasopharyngeal carcinoma,overall prognosis is favorable,and long-term follow-up is required.Molecular targeted therapy and immunotherapy are expected to improve the prognosis of advanced nasopharyngeal carcinoma and require further research for validation.

Objective To investigate the effectiveness of new-generation snapshot freeze(NG SSF)technology for improving image quality of coronary CT angiography(CCTA)in patients with different heart rate(HR).Methods CCTA data of 164 patients obtained with a 256-row CT scanner and voltages of 80,100 and 120 kV,respectively,in one cardiac cycle were retrospectively analyzed.Smart electrocardiogram(ECG)gating technology was used to calculate patient's HR and choose automatic exposure phase.For these with HR≤65 beats/min(low HR group),the exposure time window was set between 70%—80%R-R interval,for 65 beats/min＜HR≤85 beats/min(medium HR group)was set between 40%—80%R-R interval,while for those HR＞85 beats/min(high HR group)was set between 40%—60%R-R interval.Standard reconstruction(STD),the first-generation snapshot freeze(SSF1)and NG SSF were performed to reconstruct CCTA images,respectively.Subjective scoring of each segment of right coronary artery(RCA),left anterior descending(LAD)and left circumflex artery(LCX)shown on CCTA were performed based on Likert scale.Results In low HR group,the scores of middle and distal segments of LAD and all segments of RCA and LCX on NG SSF CCTA were significantly higher than on STD,and of middle segment of RCA and distal segment of LAD were both higher than on SSF1(all P＜0.05).In medium HR group,the scores of all branches on NG SSF CCTA were significantly higher than on STD or SSF1 CCTA(all P＜0.05).In high HR group,the scores of coronary branches showed on NG SSF CCTA were all significantly higher than on STD CCTA,while of the proximal and distal segments of RCA,middle and distal segments of LAD and all segments of LCX were significantly higher than on SSF1 CCTA(all P＜0.05).Conclusion NG SSF could effectively enhance image quality of prospective ECG-gated CCTA in patients with varying HR.

Aim To construct a model of vascular endothelial cell(EC)-specific gene knockout mice of tumor necrosis factor receptor-associated factor 2(Traf2)by using Cre-loxP technolo-gy,thus to provide basis for the research of vascular dysfunction-related diseases related to the regulation of vascular EC activity through TRAF2.Methods The Cre-loxP system was used to construct a mouse model with EC-specific knockout of Traf2 gene(Traf2flox/flox Tek-iCre+).The mouse genotype was identi-fied through PCR and gel electrophoresis.Primary vascular ECs were isolated from the mice using flow cytometry.The knockout efficiency of Traf2 in vascular ECs was validated by Western blot and immunofluorescence.The pathological changes in blood ves-sels and major organs of the mice were examined using hematox-ylin-eosin(HE)staining.The tube-forming ability of primary vascular EC was assessed using Matrigel tube formation.Results The knockout mice met the required genetic criteria.Flow cy-tometry results demonstrated the successful isolation of primary vascular EC,and TRAF2 expression in vascular EC of knockout mice was significantly reduced(P＜0.01).Histological results showed that TRAF2 expression in the vessel of knockout mice decreased,and the morphology had no significant changes in their blood vessels and major organs.The Matrigel tube forma-tion demonstrated that the tube-forming ability of primary vascu-lar EC from knockout mice was reduced.Conclusion Traf2 specific knockout mouse model in vascular ECs is successfully constructed,providing a reliable animal model for research into the regulatory mechanisms of TRAF2 on vascular ECs in vascular dysfunction related diseases.

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.

Objective To find and select stable and specific identification indexes in chest CT images,to establish mathematical models and provide a systematic and scientific identification method.Methods Medical imaging analysis and processing technology were applied to compare the image indexes such as lung apical shadow,double lung texture,trachea,sternum,thoracic morphology,liver,spleen,interlobular fissure morphology,first rib,aorta and thoracic vertebrae morphology of 600 serial chest CT scans of of the same adults at different periods and 600 scans of different adults.Consistency test(Kappa analysis)was applied to determine the consistency of different identification indexes,and to screen out the image identification indexes that were not easily affected by subjective factors and had high consistency;the cumulative exclusion probability method was applied to calculate the combined identification ability of the observation indexes,and select optimal indexes to establish the identification index system.Results Five indexes-left lung texture,right lung texture,interlobular fissure of the liver,first rib on the left side,and first rib on the right side demonstrated high consistency across age groups and minimal subjective interference.A combination of any three indexes achieved＞99.99％discrimination probability for homologous versus non-homologous sources identification.Conclusion The independent or combined use of the indexes of left lung texture,right lung texture,interlobular fissure of the liver,first rib on the left side,and first rib on the right side enables individual identification in adult chest CT under different imaging conditions.

At present,the laboratory medicine industry in China has developed rapidly,with various new technologies and methods emerge one after another. However,the current training process of laboratory medicine technology professionals still follows a training model that emphasizes theyory over practice,and the quality of training personnel is far from the requirments of the current development of the laboratory medicine industry in China. In order to effectively alleviate the current situation of the shortage of practical high-quality laboratory medicine talents,it is urgent to reform the teaching of laboratory medicine. The author of this paper puts forward the "Four-in-one" personnel training mode which is suitable for the development of laboratory medicine in China. It is proposed to explore a new teaching mode on the basis of the existing one,giving full play to the students' initiative and innovation,and providing new ideas for training high-quality laboratory medicine professionals.