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 explore clinical effect of precast curvature internal fixation with Kirschner needle in treating forearm fracture in children.Methods From October 2019 to December 2022,32 children with forearm fractures were treated with precast curvature internal fixation with Kirkler's needles,including 25 males and 7 females,aged from 3 to 15 years old with an average of(8.0±0.5)years old,18 patients on the left side and 14 on the right side,24 patients with double fractures of radial and ulna,3 patients with Monteggia fractures,and 4 patients with Galeazzi fractures,and 1 patient with radial neck frac-ture of crooked cap.Operation time,intraoperative blood loss,C-arm fluoroscopy,fracture healing time and complications were recorded,and disabilities of arm,shoulder and hand(DASH)scale and Grace-Eversman forearm double fracture evaluation system were used to evaluate clinical efficacy of precast curvature internal fixation with Kirschner's needle for forearm fracture in children.Resluts All 32 patients were followed up for 2 to 12 months with an average of(7.16±2.51)months.Intraoperative blood loss was(20.68±5.50)ml,C-arm fluoroscopy was(5.80±2.50),and operation time was(24.34±5.10)min,fracture healing time was(8.82±1.62)weeks.Two patients occurred complications,including postoperative rupture of extensor pollicis longus tendon in 1 patient and obvious displacement of fracture caused by rotation of prefabricated curvature Kirschler needle on bone marrow cavity in 1 patient.DASH scores ranged from 0 to 16 scores with an average of(8.32±1.50)scores.According to Grace-Eversman double fracture evaluation system,28 patients got excellent result,2 good and 2 fair.Conclusion The treatment of forearm fracture with Kirschner's needle prefabricated curvature internal fixation has advantages of less trauma,less bleeding,good reduction,stable fixation,fast fracture healing and good functional recovery.

Osteoporosis is an important cause of internal fixation loosening after spinal surgery.Cement-augmented pedicle screw instru-mentation(CAPSI)technique is the most widely used technique in clinical practice to improve the stability of pedicle screw,mainly applied in osteoporosis and revision surgery,which included conventional solid pedicles crews and fenestrated/cannulated pedicle screws technique.CAPSI technique may cause cement leakage and pulmonary embolism,and there is no consensus on its indications or technical points.Therefore,this article reviews the research progress of CAPSI,in order to provide relevant reference for clinical practice.

Objective To explore the value of artificial intelligence federated learning system based on chest X-ray films for pathogen diagnosis of community-acquired pneumonia(CAP)in children.Methods Totally 900 cases of CAP children from 2 hospitals were retrospectively enrolled,including bacterial,viral and mycoplasma CAP(each n=300),and chest posteroanterior X-ray films were collected.Meanwhile,chest posteroanterior X-ray films of 5856 children from the publicly available dataset GWCMCx were collected,including 4273 CAP images and 1583 healthy chest images.All above 6756 images were divided into training set(n=5359)and validation set(n=1397)at the ratio of 8∶2.Then a pathogen diagnosis model of children CAP was established based on attention mechanism.Binary and ternary diagnostic algorithms were designed,and federated deployment training was performed.The efficacy of this system for pathogen diagnosis of children CAP was analyzed and compared with DenseNet model.Results Based on all data,the accuracy of the obtained artificial intelligence federated learning system model for diagnosing children CAP was 97.00%,with the area under the curve(AUC)of 0.990.Based on hospital data,the AUC of this system using single imaging data and clinical-imaging data for pathogen diagnosis of children CAP was 0.858 and 0.836,respectively,both better than that of DenseNet model(0.740,both P＜0.05).Conclusion The artificial intelligence federated learning system based on chest X-ray films could be used for pathogen diagnosis of children CAP.

Ketamine,an antagonist of the glutamate N-methyl-D-aspartate(NMDA)receptor,is cur-rently one of the most widely abused psychoactive substances.Prolonged abuse can result in damages to various systems in the body,making it crucial to investigate the regulatory mechanism of ketamine addic-tion and screening related biomarkers.In this study,zebrafish embryos/larvae were initially exposed a-cutely to ketamine.Then,a ketamine addiction model was established in 6-month-old zebrafish through conditioned place preference(CPP)experiments.The zebrafish brain transcriptome was analyzed using RNA-seq,while qPCR and Western blotting were employed to detect the expression of key genes.Results revealed significant reductions in the spontaneous tail coiling,embryo hatching rate,and survival rate of zebrafish embryos in the ketamine-treated group compared to the control group.The distance moved also decreased significantly,from 1904.2 mm in the control group to 319.0 mm in the high dose of ketamine group(300 μmol/L).Conditional positional preference experiments demonstrated that the control ze-brafish did not exhibit significant changes in activity in the CPP tank.In contrast,the ketamine-treated group increased their activity time in the light zone of the tank from 385.2 s before training to 706.4 s af-ter training,representing a 26.8％increase(***P＜0.001).This suggests a preference for ketamine stimulation in zebrafish.KEGG analysis indicated enrichment of differentially expressed genes in the neu-roactive ligand-receptor interaction pathway in the ketamine-treated samples.GSEA analysis further re-veals a significant upregulation of the glutamatergic synapse pathway(NES=1.5).In addition,compared with the control group,the mRNA levels of Grin2b and Gria2 in the ketamine group increased by 4.6 and 1.4 times,respectively,while the protein levels increased by 2.0 and 1.4 times,respectively.These findings suggest that ketamine can induce addiction in zebrafish,potentially through upregulation of the glutamatergic synaptic pathway.

Objective:To investigate the toxic effect of chlorambucil combined with ibrutinib on mantle cell lymphoma(MCL)cell line Jeko-1 and its related mechanism.Methods:The MCL cell line Jeko-1 was incubated with different concentrations of chlorambucil or ibrutinib or the combination of the two drugs,respectively.CCK-8 assay was used to detect the proliferation of the cells,and Western blot was used to measure the protein expression levels of BCL-2,caspase-3,PI3K,AKT and P-AKT.Results:After Jeko-1 cells were treated with chlorambucil(3.125,6.25,12.5,25,50 μmol/L)and ibrutinib(3.125,6.25,12.5,25,50 μmol/L)alone for 24,48,72h respectively,the cell proliferation was inhibited in a time-and dose-dependent manner.Moreover,the two drugs were applied in combination at low doses(single drug inhibition rate＜50％),and the results showed that the combination of two drugs had a more significant inhibitory effect(all P＜0.05).Compared with the control group,the apoptosis rate of the single drug group of chlorambucil(3.125,6.25,12.5,25,50 μmol/L)and ibutinib(3.125,6.25,12.5,25,50 μmol/L)was increased in a dose-dependent manner.The combination of the two drugs at low concentrations(3.125,6.25,12.5 μmol/L)could significantly increase the apoptosis rate compared with the corresponding concentration of single drug groups(all P＜0.05).Compared with control group,the protein expression levels of caspase-3 in Jeko-l cells were upregulated,while the protein expression levels of BCL-2,PI3K,and p-AKT/AKT were downregulated after treatment with chlorambucil or ibrutinib alone.The combination of the two drugs could produce a synergistic effect on the expressions of the above-mentioned proteins,and the differences between the combination group and the single drug groups were statistically significant(all P＜0.05).Conclusion:Chlorambucil and ibrutinib can promote the apoptosis of MCL cell line Jeko-1,and combined application of the two drugs shows a synergistic effect,the mechanism may be associated with the AKT-related signaling pathways.

Objective:To explore and stimulate the pathway mechanism for doctors from core hospitals,which are the high-quality medical resources in loose medical alliances,to sink to the grassroots level on their own initiative and continue to participate in the co-operation,so as to provide useful references for improving the effectiveness of cooperation within medical alliances.Methods:The fuzzy set Qualitative Comparative Analysis(fsQCA)method was used to investigate 205 doctors in the core hospitals of a loose medical alliance in District X of City B.This investigation was grounded in relationship commitment theory,motivation theory,social exchange theory,and cooperation reinforcement theory.Results:The level of relationship commitment of doctors in the core hospitals to proactively participate in cooperation was influenced by multiple factors,including doctors'perception of job significance,opportunity cost perception,organizational support,and teamwork experience.This resulted in the formation of three concurrent driving mechanism pathways:merger-driven effect,experience-enhancing effect,and altruistic trigger effect.Among these factors,the perception of work significance was a necessary condition,and cooperative experience played an important role in doctors'continuous participation.Conclusion:The level of relational commitment of doctors to participate in cooperative efforts is driven by a combination of various factors,with different incentive mechanisms exhibiting heterogeneity within loose medical alliances.Designing appropriate incentive and support strategies tailored to specific contexts can effectively drive the proactive downward flow of high-quality medical resources from core hospitals within loose medical alliances.

Objectives:To assess the clinical characteristics and lead extraction in patients with venous occlusion related to infection of cardiovascular implantable electronic devices. Methods:Clinical data of 405 patients(147 men,mean age[62.4±13.2]years)who underwent lead extraction from January 2020 to January 2024 in Peking University People's Hospital were reviewed.Contrast venography of the access vein was retrospectively analyzed.The patients were divided into venous occlusion group(n=119)and non-venous occlusion group(n=286)according to the presence or absence of venous occlusion.The clinical characteristics and lead extraction of patients in two groups were analyzed. Results:Occlusion of the access vein occurred in 119 patients(29.4%).The subclavian vein was occluded in 48 cases(40.3%),brachiocephalic vein was occluded in 37 cases(31.1%),axillary vein was occluded in 30 cases(25.2%),superior vena cava was occluded in 4 cases(3.4%).There were no significant differences between venous occlusion group and non-venous occlusion group in terms of age,sex,device type,number of leads,or anticoagulation therapy(all P>0.05).Time from implant of the initial leads was significantly longer in the venous occlusion group than in the non-venous occlusion group([10.4±3.8]years vs.[5.9±4.1]years,P=0.042).Clinical extraction success rate and complications were similar between the venous occlusion group and the non-venous occlusion group(both P>0.05).Procedural duration and fluoroscopy exposure time were significantly lower in non-venous occlusion group than in the venous occlusion group(both P<0.05).Patients in the venous occlusion group required more advanced tools(such as laser sheaths,evolution sheaths,and needle's eye snares)for lead extraction compared to patients in the non-venous occlusion group(84.0%vs.67.1%,P=0.001). Conclusions:The incidence of venous occlusion related to infection of cardiovascular implantable electronic devices is 29.4%.Time from implant of the initial leads is significantly longer and lead extraction is more difficult in patients with venous occlusion,and requires more advanced tools and more time to achieve the successful lead extraction.

The research status of the actuation technology of wearable exoskeletons was introduced.Kinds of actuation technologies and actuators were analyzed in terms of advantage,disadvantage and applicable scenario.It's pointed out the actuation technology of wearable exoskeletons should be oriented to high-performance micro-motors,new actuators,actuation modularity and intellectualization.[Chinese Medical Equipment Journal,2024,45(4):104-110]

Further evidence is needed to explore the impact of high-altitude environments on the neurologic function of neonates.Non-invasive techniques such as cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography can provide data on cerebral oxygenation and brain electrical activity.This study will conduct multiple cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography monitoring sessions at various time points within the first 3 days postpartum for healthy full-term neonates at different altitudes.The obtained data on cerebral oxygenation and brain electrical activity will be compared between different altitudes,and corresponding reference ranges will be established.The study involves 6 participating centers in the Chinese High Altitude Neonatal Medicine Alliance,with altitude gradients divided into 4 categories:800 m,1 900 m,2 400 m,and 3 500 m,with an anticipated sample size of 170 neonates per altitude gradient.This multicenter prospective cohort study aims to provide evidence supporting the impact of high-altitude environments on early brain function and metabolism in neonates.[Chinese Journal of Contemporary Pediatrics,2024,26(4):403-409]