BACKGROUND:The guinea pig is considered to be the most useful spontaneous model for evaluating primary osteoarthritis in humans because of its similar knee joint structure and close histopathologic features to those of humans. OBJECTIVE:To investigate the pathological process of spontaneous knee osteoarthritis in guinea pigs by analyzing the histopathology of the total knee joint of guinea pigs aged 1 to 18 months. METHODS:Eight healthy female Hartley guinea pigs in each age group of 1,6,10,14,16,and 18 months old were selected.The quadriceps femoris was taken for hematoxylin-eosin staining,and the total knee joint was stained with hematoxylin-eosin and toluidine blue.The histopathology of the cartilage,subchondral bone,synovium,meniscus,and muscles were observed under light microscope.Mankin's score and synovitis score were compared,and the correlation analysis was conducted. RESULTS AND CONCLUSION:As the guinea pig age increased,the Mankin's score increased(P<0.05),and the pathological score of synovitis also gradually increased(P<0.05),and there was a significant positive correlation between the two(r=0.641,P<0.001).The incidence rate of subchondral bone marrow lesion in 18-month-old guinea pigs was 50%,and the incidence of meniscus injury was 37.5%.In addition,osteophyte and narrowing of the joint space were observed,and only a few guinea pigs had inflammation in the quadriceps femoris.To conclude,guinea pigs develop significant cartilage defects,synovial inflammation,subchondral bone lesions,meniscus injury,osteophyte formation,and joint space narrowing as they age,all of which are similar to the pathological processes of primary knee osteoarthritis in humans,making it an ideal model of spontaneous knee osteoarthritis.

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.

This study was aimed at exploring novel auxiliary diagnostic biomarkers for brucellosis and their potential miR-NA-mRNA regulatory networks.High-throughput sequencing was used to compare miRNA expression differences in serum ex-osomes between patients with brucellosis and healthy controls.Subsequently,RT-qPCR was used to validate the expression of significantly upregulated exosomal miRNAs.The diagnostic value of these miRNAs was assessed with ROC curves,and bioin-formatics analyses were performed to investigate the potential roles of the miRNAs in brucellosis infection.The ROC curve a-nalysis indicated that the area under the curve for exosomal hsa-miR-11400(P＜0.05),hsa-miR-199a-5p(P＜0.05),and hsa-miR-148a-5p(P＜0.05)was 0.79,0.81,and 0.74,respectively.A total of 465 differentially expressed miRNAs and their tar-get genes were predicted,including 25 immune-related target genes,most of which were closely associated with cancer-related proteoglycans,NF-kappa B signaling pathways,and IL-17 signaling pathways.The constructed differentially expressed gene network indicated that the immune genes PLXNA2,IL17RA,PRKCA,CD22,ACVR1B,and CBL might be regulated by hsa-miR-199a-5p and hsa-miR-148a-5p.These findings suggest that exosomal miRNAs might serve as auxiliary diagnostic indicators for brucellosis.Our exosomal miRNA-mRNA regulatory network provides new insights into the pathogenesis and treatment of brucellosis.

Based on the target recognition ability of split aptamer and intelligent analytical capability of molecular logic gate,in this work,two split aptamers were integrated into"AND"logic gate to construct a novel ortho-nucleic acid fluorescence sensor for simultaneous detection of thrombin and myoglobin.When there was one target,the response of the signal was only a single fluorescence output signal,which was used as an evaluation standard for early low-risk judgment.When two targets coexisted,the split aptamer bound to the target to form a ternary complex and led to the head and tail ortho-nucleic acid effect respectively,and triggered the G4 chain to enhance the fluorescence signal of thioflavin T and the fluorescence signal quenching of Cyanine 3,which could be used as an evaluation criterion for early high-risk judgement.Under the optimal conditions,the linear range for detection of thrombin was 3-200 nmol/L,with a correlation coefficient of 0.9931 and a detection limit of 0.97 nmol/L,and the linear range for detection of myoglobin was 6-400 nmol/L,with a correlation coefficient of 0.9933,and a detection limit of 2.14 nmol/L.The method was applied to simultaneous determination of thrombin and myoglobin in clinical serum samples,and the recoveries were 85.4%-118.3%and 85.8%-119.9%,respectively,with relative standard deviations of less than 6.5%.Compared with the standard method,the relative error range was from-8.8%to 5.6%.In addition,the logical diagnosis results of 4 serum samples were high-risk of acute myocardial infarction in 2 cases and low-risk in 2 cases.The ″AND″ logic gate ortho-nucleic acid fluorescence sensing method showed many advantages such as high selectivity,rapidity,accuracy and simultaneous detection,which offered important reference for early diagnosis of acute myocardial infarction,and also provided a general detection design strategy and platform for simultaneous detection of biomarkers.

The construction of first-class universities and disciplines is a major strategic initiative of the Communist Party of China Central Committee and the State Council,and an important task for building a world-class higher education powerhouse.Forensic medicine was officially listed as a first-level discipline under the medical category in 2022,presenting unprecedented historical opportunities for the development of forensic medicine.Facing this significant strategic opportunity,this paper sorts out the disciplinary system of forensic medicine,carries out forward-looking planning for the develop-ment of the discipline,and looks forward to the development vision of the discipline:(1)Establish an organically connected three-stage forensic medicine talent training system to cultivate applied and innovative talents that meet the needs of China's socialist modernization construction;(2)Establish a unified standardized forensic practice qualification examination system,organically connect talent training with professional qualification examination,and optimize the professional development path of forensic medicine;(3)Widely intersect,integrate and transform forensic medicine with other multiple disciplines,expand and enrich the second-and third-level disciplinary systems of forensic medicine,and build a world-class forensic medicine discipline with Chinese characteristics.

Objective:To explore the correlation between the intensity of net ultrafiltration in continuous renal replacement therapy (CRRT) and the survival prognosis in critically ill patients with acute kidney injury (AKI), and provide evidence-based references for establishing optimal net ultrafiltration target during CRRT.Methods:This was a retrospective observational study. Demographic and clinical data of critically ill AKI patients who received CRRT in the Intensive Care Unit of West China Hospital, Sichuan University from May 2021 to September 2023 were collected. Net ultrafiltration was defined as the hourly fluid clearance volume in the 72 hours prior of CRRT. This variable was converted into a categorical variable, including low net ultrafiltration <1.01 ml·kg -1·h -1, moderate net ultrafiltration 1.01-1.38 ml·kg -1·h -1 and high net ultrafiltration >1.38 ml·kg -1·h -1, and the differences of baseline characteristics and clinical treatment conditions among the three groups were compared. Kaplan-Meier survival curve and log-rank test were used to compare the survival conditions among the three groups in patients at 28 days and 60 days after CRRT. Logistic regression analysis method was used to analyze the related factors of mortality in patients 28 days and 60 days after CRRT. Results:This study included a total of 661 critically ill AKI patients who underwent CRRT for more than 72 hours. The age was 56.00 (43.00, 68.00) years, and 488 patients (73.83%) were males. The net ultrafiltration rate was 1.36 (0.94, 1.89) ml·kg -1·h -1. Among them, 188 patients (28.44%) were in the low net ultrafiltration group, 152 patients (23.00%) were in the medium net ultrafiltration group, and 321 patients (48.56%) were in the high net ultrafiltration group. There were statistically significant differences among the three groups in terms of gender distribution ( χ2=17.81, P<0.001), body mass index ( H=32.37, P<0.001), urine volume 24 hours before admission ( H=9.41, P=0.009), fluid overload ( H=6.02, P=0.049), platelets ( H=13.49, P=0.001), pro-B type natriuretic peptide ( H=14.18, P<0.001), serum creatinine ( H=9.66, P=0.008), lactate ( H=9.83, P=0.007), AKI stage distribution ( χ2=15.51, P=0.004), admission indication ( P<0.001), total CRRT duration ( H=8.45, P=0.015), ultrafiltration ( H=456.10, P<0.001), net ultrafiltration ( H=561.20, P<0.001), and vasoactive-inotropic score at 72 hours of CRRT treatment ( H=10.42, P=0.005). Kaplan-Meier survival analysis showed that there were statistically significant differences in the 28-day (Log-rank test, χ2=10.89, P=0.004) and 60-day (Log-rank test, χ2=8.55, P=0.014) survival rates among the three groups in patients after CRRT. Multivariate logistic regression analysis showed age ( OR=1.03, 95% CI 1.02-1.04, P<0.001), mean arterial pressure ( OR=0.98, 95% CI 0.97-1.00, P=0.011), bilirubin ( OR=3.02,95% CI 1.39-5.59, P=0.006), 72-hour vasoactive-inotropic score ( OR=1.01, 95% CI 1.00-1.02, P=0.004), low net ultrafiltration group (medium net ultrafiltration group as a reference, OR=1.66, 95% CI 1.02-2.72, P=0.042), and high net ultrafiltration group (medium net ultrafiltration group as a reference, OR=1.78, 95% CI 1.14-2.78, P=0.011) were independent correlated factors of 28-day mortality after CRRT. Age ( OR=1.02，95% CI 1.01-1.04， P<0.001), mean arterial pressure ( OR=0.98，95% CI 0.97-1.00， P=0.016), fluid overload ( OR=1.10, 95% CI 1.02-1.19, P=0.012), bilirubin ( OR=4.96，95% CI 1.00-17.80， P=0.013), 72-hour vasoactive-inotropic score ( OR=1.02，95% CI 1.01-1.03， P=0.003), and high net ultrafiltration group (medium net ultrafiltration group as a reference, OR=1.91，95% CI 1.22-3.00， P=0.005) were independent correlated factors of 60-day mortality after CRRT. Conclusions:During the first 72 hours of CRRT, net ultrafiltration > 1.38 ml·kg -1·h -1 and net ultrafiltration < 1.01 ml·kg -1·h -1 are associated with a higher mortality rate at 28 days or 60 days after CRRT. Net ultrafiltration of 1.01-1.38 ml·kg -1·h -1 may be a relatively safe range.

Objective:To investigate the clinical features, pathologic characteristics, treatment and prognosis of primary mediastinal large B-cell lymphoma (PMBCL) in children.Methods:Clinical data including clinical manifestations, treatment, clinical efficacy of 8 cases of childhood PMBCL treated in Beijing Children′s Hospital, Capital Medical University from March 2017 to February 2024 were collected retrospectively, the clinical characteristics and prognosis of them were summarized.Results:Among the 8 children, there were 5 males and 3 females. The age at the time of initial diagnosis was 11.0 (10.3, 13.5) years. The first clinical symptoms were cough (8 cases) and stridor (6 cases). The lesions most often involved the mediastinum (8 cases), lungs (5 cases, hilum more often), pericardium (5 cases), and pleura (4 cases). Extra thoracic invasion was present in 4 cases, 7 cases had huge tumor lesions and 7 cases were phase Ⅲ clinical stage. Except for 1 case who underwent surgical resection of the tumor, the remaining 7 cases were treated with DA-EPOCH+R (dose adjusted-etoposide+prednisone+vincristine+cyclo-phosphamide+doxorubicin+rituximab) chemotherapy. The follow-up time was 25.0 (10.5, 43.3) months, with 7 cases in complete and partial metabolism response, 1 case had disease progression. All 8 cases survived.Conclusions:PMBCL is most common in school-age boys and most of them present with huge mediastinal tumor focus. PMBCL expresses B-cell spectrum antigens and weakly expresses CD30.The application of DA-EPOCH+R is effective in the treatment of PMBCL in children.

Objective:To evaluate the clinical characteristics, pathology, treatment and prognosis of blastic plasmacytoid dendritic cell neoplasm (BPDCN) in children.Methods:Clinical data (including gender, age of disease onset, affected sites, treatment, timing of allogeneic hematopoietic stem cell transplantation (allo-HSCT), etc.) of 7 children with BPDCN who were admitted to Beijing Children′s Hospital, Capital Medical University from December 2018 to December 2023 were analyzed retrospectively. Clinical outcomes were also assessed, with patients followed up until December 2024.Results:Among 7 patients, there were 3 males and 4 females. Age at disease onset ranged from 3.2 to 12.9 years. Initial presentations included subcutaneous nodules in 5 cases, rash in 1 case, and ankle pain in 1 case. Extra-cutaneous involvement was seen in the bone marrow, lymph nodes, and central nervous system. Six patients received induction chemotherapy using a modified lymphoblastic lymphoma regimen, 1 patient received the high-risk protocol for pediatric lymphoblastic lymphoma/leukemia and salvage therapy regimens. Allo-HSCT was performed soon after chemotherapy remission. The time to bridge allo-HSCT was 3.5 to 6.5 months. The follow-up time was 1.6 to 6.0 years. Six patients were in disease-free survival, while 1 patient survived with disease after recurrence following transplantation.Conclusions:BPDCN is rare in children and presents diverse clinical manifestations, with skin involvement being the predominant feature. Early allo-HSCT following complete remission with chemotherapy can improve prognosis.

Objective To investigate the effects of Bushen Shengjing Tiaohe Qixue Prescription on rats with diminished ovarian reserve(DOR)based on Wnt/β-catenin signaling pathway.Methods Totally 60 8-week-old SD female rats were randomly divided into control group,model group,estradiol valerate group and TCM low-,medium-and high-dosage groups,with 10 rats in each group.Except for the control group,the rats in the other groups were given a single intraperitoneal injection of cyclophosphamide 75 mg/kg to replicate the DOR rat model.From the next day of modeling,the corresponding drugs was administered for medication groups by gavage for 3 weeks.The general conditions of the rats were observed,ELISA was used to detect the contents of serum follicle-stimulating hormone(FSH),luteinizing hormone(LH),estradiol(E2),anti-mullerian hormone(AMH)and inhibin B(INHB),HE staining was used to observe the morphologic changes in ovarian tissue,Western blot was used to detect GSK3β,β-catenin,CyclinD1 and c-MYC protein expressions in ovarian tissues,immunohistochemical staining was used to observe β-catenin expression in ovarian tissue,RT-qPCR was used to detect Wnt1,Wnt2,Wnt4,GSK3β,β-catenin,CyclinD1 and c-MYC mRNA expression in ovarian tissue,transmission electron microscopy was used to observe ultrapathologic structure of ovarian granulosa cells.Results Compared with the control group,the rats in the model group had reduced intake of food and water,slow or even reduced body mass gain,and disturbed estrous cycle,the serum contents of FSH and LH increased(P<0.01),the contents of E2,AMH and INHB decreased(P<0.01);the number of follicles of all levels in ovarian tissue was reduced,and there was increased number of atretic follicles with disturbed arrangement of the granulosa cells;the expression of GSK3β protein in ovarian tissue increased(P<0.01),the expression of β-catenin,CyclinD1 and c-MYC protein decreased(P<0.05,P<0.01),and β-catenin positive expression decreased(P<0.01),the expression of Wnt1,Wnt2,Wnt4,β-catenin,CyclinD1 and c-MYC mRNA in ovarian tissue decreased(P<0.01),GSK3β mRNA expression was increased(P<0,01);organelles such as mitochondria and nuclei of ovarian granulosa cells were highly swollen and partially lysed.Compared with the model group,the rats in the administered group all had different degrees of body mass increase,partial restoration of the motility cycle,serum FSH and LH contents decreased,and serum E2,AMH and INHB contents increased(P<0.01,P<0.05);the number of follicles at all levels in ovarian tissue increased to varying degrees,and the atretic follicles were reduced;the expression of GSK3β protein in ovarian tissue decreased,β-catenin,CyclinD1 and c-MYC protein expressions increased,β-catenin positive expression increased,the expression of Wnt1,Wnt2,Wnt4,β-catenin,CyclinD1 and c-MYC mRNA in ovarian tissue increased,and GSK3β mRNA expression decreased,with statistical significance in estradiol valerate group and TCM high-dosage group(P<0.05,P<0.01);mitochondria,endoplasmic reticulum and other organelles of ovarian granulosa cells were mildly to moderately swollen.Conclusion Bushen Shengjing Tiaohe Qixue Prescription can improve ovarian function and regulate serum sex hormone levels in DOR model rats,and its mechanism might be related to the activation of Wnt/β-catenin signaling pathway.