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 establish 30-day of age transcutaneous bilirubin (TcB) reference curves for healthy neonates, and to investigate regional variations in bilirubin dynamics.Methods:A multicenter retrospective cohort study was conducted. A total of 220 950 healthy neonates born at a gestational age of 35-<42 weeks, with a birth weight ≥2 000 g, who did not receive phototherapy within 60 h after birth were recruited. All of them underwent remote TcB monitoring using the Bilibaby remote jaundice monitoring system between August 1 st, 2020 and December 31 st, 2024 in 426 hospitals. TcB data were collected within the period from birth to 30-day of age. The P40, P75, and P95 of TcB values were calculated, and dynamic TcB curves for 30-day of age were constructed. Patterns of bilirubin change, rates of change, and transition outcomes were described. Regional comparisons between South and North were conducted using linear mixed-effects models for TcB trajectories and Pearson′s chi-square test for outcome differences. Results:A total of 220 950 neonates were included, of whom 101 711 (46.03%) were female. Gestational age at birth was (38.75±1.12) weeks, and birth weight was (3 272±417) g. TcB levels increased rapidly within 3-day of age, peaked at 4-6-day of age, with peak values at P40, P75, and P95 of 200.6, 239.7 and 275.4 μmol/L (11.8, 14.1 and 16.2 mg/dl), respectively. TcB levels gradually declined thereafter and stabilized after 13-day of age, with values at P40, P75, and P95 fluctuating between 147.9-159.8, 190.4-200.6, and 231.2-239.7 μmol/L (8.7-9.4, 11.2-11.8, 13.6-14.1 mg/dl), respectively. Notably, among neonates categorized as low-or low-intermediate-risk within 3-day of age, 6 700 (12.76%) progressed to intermediate-high or high risk between 4 and 30 days of age. Before 13-day of age, TcB levels in the southern regions were consistently higher than those in the northern regions ( P=0.039); from 14 to 30 days of age, the overall TcB levels had no statistically difference, but the temporal changes in TcB still showed regional differences (degrees of freedom=3, all interaction P<0.05). Among neonates classified as low-or low-intermediate risk within 3-day of age, 25 326 were from southern regions, of whom 4 254 (16.80%) progressed to intermediate-high or high risk between 4 and 30 days of age. In northern regions, 27 193 neonates were classified as low-or low-intermediate risk within 3-day of age, among whom 2 446 (8.99%) progressed to intermediate-high or high risk. The risk progression between the 2 regions had statistically difference ( χ2=716.49, P<0.001). Conclusions:A TcB percentile curve for neonates within 30-day of age was established, revealing that both the overall TcB level and its temporal trend were higher in southern than in northern newborns. These findings provide baseline data to support continuous management of neonatal jaundice.

Objectives:To evaluate the performance of AVEIR VR single chamber leadless pacemaker(AVEIR VR)in the real world in China and the predictive factors of pacing threshold to assess the feasibility of AVEIRTM VR implantation in the domestic population.Methods:All patients who underwent AVEIR VR implantation by experienced operators from Peking University People's Hospital in multiple domestic hospitals from June 2024 to October 2024 were consecutively included,and their baseline characteristics,procedural data(including pacemaker electrical measurements at various stages),and follow-up results were observed,recorded,and statistically analyzed.Results:This study included 20 patients who met the indication for pacemaker implantation and underwent AVEIR VR implantation.Their mean age was(71.40±13.37)years,body mass index(BMI)was(23.05±3.71)kg/m2,body surface area(BSA)was(1.70±0.16)m2,all 20 patients were successfully implanted with pacemakers,there were no major complications(newly occurred pericardial effusion during the perioperative period,cardiac tamponade,poor pacemaker function,pacemaker dislocation/perforation,tricuspid valve injury,myocardial infarction,stroke,pulmonary embolism,and clinical death).One patient developed new frequent ventricular premature contractions after pacemaker release.The pacing threshold(PCT)at one week after implantation was correlated with PCT in tether mode(r=0.650,P=0.009)and PCT in release phase(r=0.596,P=0.019),but not with the sensing and impedance in each phase.Conclusions:This preliminary exploration study show that AVEIRTM VR implantation demonstrates satisfactory performance among real world patients in China,especially in elderly and low weight populations,confirming its safety.

Objective:To evaluate the clinical feasibility of subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation following transvenous lead extraction (TLE).Methods:This was a retrospective study. Consecutive patients who underwent S-ICD implantation at Peking University People′s Hospital between June 2015 and October 2023 were enrolled. Patients were divided into the TLE group and the newly implanted group based on whether they received TLE prior to S-ICD implantation. Baseline characteristics, S-ICD indication, defibrillation threshold test results, complications, and postoperative follow-up data were collected and compared between the two groups.Results:A total of 27 patients were included, aged (49.2±14.2) years, including 19 males. There were 12 patients in the TLE group and 15 in the newly implanted group. Compared with the TLE group, patients in the newly implanted group were younger ((43.3±13.7) years vs. (55.6±12.0) years, P=0.013). The main S-ICD indication in the TLE group was high infection risk (9/12), whereas in the newly implanted group it was younger age (11/15). All patients underwent successful S-ICD implantation, with 18 patients completing defibrillation threshold testing (all successful). Additionally, the TLE group had longer follow-up duration than the newly implanted group (42 (19, 60) months vs. 12 (3, 28) months, P=0.001). No complications or deaths occurred during follow-up, with normal device function in both groups. A total of 17 ventricular tachycardia or fibrillation events were recorded, of which 7 met defibrillation criteria and all received effective therapy. Conclusion:S-ICD demonstrates safety and efficacy as a therapeutic option for patients after TLE, with comparable device functionality and follow-up outcomes to patients with newly implanted S-ICD.

Aim To investigate the regulatory mecha-nisms of donepezil on the expression and enzymatic ac-tivity of cytochrome P450 3A4(CYP3A4),elucidate the synergistic impact of hypoxia on CYP3A4 function,and reveal its potential association with drug-induced cardiotoxicity,particularly QT interval prolongation.Methods Western blot,co-immunoprecipitation,and gene knockdown techniques were employed to evaluate the effects of donepezil and hypoxia on CYP3A4 pro-tein expression.CYP3A4 enzymatic activity was as-sessed using an in vitro incubation system with rat liver microsomes combined with high-performance liquid chromatography(HPLC),and the half-maximal inhib-itory concentration(IC50)was determined.Results Donepezil(10 μmol·L-1)and hypoxia reduced CYP3A4 protein expression to 31.75％and 45.90％of the control levels,respectively.Both interventions activated the gp78-mediated ubiquitin-proteasome path-way,significantly increasing CYP3A4 ubiquitination levels by 2.1-fold compared to the control group,thereby promoting proteasomal degradation.Donepezil inhibited CYP3A4 enzyme activity with an IC50 of 83.4μmol·L-1,and hypoxia synergistically enhanced this inhibitory effect,reducing the IC50 to 20.79 μmol·L-1.Conclusion Donepezil downregulates CYP3A4 function through dual mechanisms involving ubiquitin-mediated proteasomal degradation and direct enzymatic inhibition.Hypoxia potentiates this effect,leading to impaired metabolism of CYP3A4 substrate drugs,ele-vated plasma drug concentrations(1.6-2.3-fold in-crease compared to normal metabolic conditions),and an increased risk of QT interval prolongation and other forms of cardiotoxicity.

Objective:To observe the analgesic effect of esketamine combined with ultrasound-guided sciatic nerve block on elderly patients with lower limb fractures and its impact on vital signs and sleep quality.Methods:92 elderly patients with lower limb fractures who were admitted to our hospital from August 2022 to August 2024 were divided into control group(injection of ropivacaine,n=46)and observation group(injection of esketamine combined with ropivacaine,n=46)by using random number table method.The Visual analogue pain score(VAS)in resting and active states,mean arterial pressure(MAP),heart rate(HR),interleukin-6(IL-6),tumor necrosis factor-α(TNF-α),cortisol(Cor),norepinephrine(NE)levels,pittsburgh sleep quality index(PSQI)between two groups were compared,and the occurrence of adverse reactions in both groups were observed.Results:Compared with the control group at 12 h and 24 h after surgery,the observation group had lower VAS scores in resting and active states(P＜0.05).Compared with the control group in tracheal extubation and 5 min after tracheal extubation,the observation group had lower HR and MAP(P＜0.05).Compared with the control group at 1 d and 3 d after surgery,the observation group had lower IL-6,Cor,NE,TNF-α and PSQI score(P＜0.05).There was no statistically significant difference in the total incidence of adverse reactions between the two groups(P＞0.05).Conclusion:Ultrasound-guided sciatic nerve block combined with esketamine on elderly patients with lower limb fractures,which has a good analgesic effect,can effectively reduce inflammatory stress response,maintain stable vital signs,improve sleep quality,and have good safety.

Objective To develop a predictive model for postoperative mortality risk in patients with acute aortic dissection(AAD)using the Extreme Gradient Boosting(XGBoost)algorithm combined with Shapley Additive Explanation(SHAP),and to establish a prediction website to serve as a diagnostic and therapeutic support platform for clinicians and patients.Methods A retrospective cohort study design was adopted.Data from 782 AAD patients who underwent surgical treatment at the Fourth Hospital of Hebei Medical University from January 2013 to December 2023 were collected,including basic information and initial serum biomarker test results.Patients were randomly divided into training and test sets at a 7:3 ratio.An external validation set consisting of 313 AAD patients admitted to the Second Hospital of Hebei Medical University from January 2020 to December 2023 was also established for further model validation.Variables were screened using LASSO regression,and an XGBoost machine learning model was constructed and interpreted using SHAP.The predictive performance of the model was evaluated using receiver operating characteristic(ROC)curve analysis.Using the Shiny package,the XGBoost model was deployed to shinyapps.io to create a prediction website for postoperative mortality risk in AAD patients.One patient was selected by simple random sampling from the test set and the external validation set respectively for the prediction example on the Shiny webpage.Results The XGBoost model demonstrated high predictive performance for postoperative mortality in AAD patients,with area under the ROC curve(AUC)values of 0.928(95%CI 0.901-0.956)in the training set,0.919(95%CI 0.891-0.949)in the test set,and 0.941(95%CI 0.915-0.967)in the external validation set.SHAP values indicated the following order of variable importance in the model(from highest to lowest):"lactate dehydrogenase""blood chlorine""multiple organ injury""carbon dioxide combining power""prothrombin time""α-hydroxybutyric acid""creatine kinase isoenzyme""Stanford classification""combined use of bedside blood purification""gender""acute kidney injury""gastrointestinal bleeding""brain injury"and"shock".A risk prediction website for adverse postoperative outcomes in AAD patients was developed using XGBoost-SHAP method(https://dun-dunxiaolu.shinyapps.io/document/)and validated with examples.One randomly selected patient from each of the test and external validation sets was applied:the predicted mortality risk value for patient 1(who died postoperatively)was 0.9539,and that for patient 2(who survived postoperatively)was 0.0206.Conclusions The XGBoost-SHAP model demonstrates high accuracy in predicting postoperative mortality risk for AAD patients.The online prediction tool established based on this model enhances the identification efficiency of high-risk postoperative mortality patients.

Objective To initially explore the possibility of applying the fluorescence micro-optical sectioning tomography(fMOST)high-resolution 3D reconstruction system to the morphological study of the intestinal nervous system and to preliminarily establish a method for studying the morphology of the intestinal nervous system using this system.Methods fMOST high-resolution 3D reconstruction system was used to study the intestinal nervous system of C57BL/6 mice in detail.Based on this method,a new morphological method of the visceral nervous system of small animal models was explored at the single-cell level.Results Compared with the large intestine,the small intestine lacked the typical myenteric plexus(Auerbach),deep mucosal plexus(Henley),and submucosal superficial plexus(Meissner).Conclusion The result of this paper provide a clearer and systematic display of the anatomical structure of the enteric nervous system in C57BL/6 mice,and further clarify the similarities and differences between the enteric nervous system of mice and human,and provide a theoretical basis for its rational application in the study of digestive system diseases.The morphological study of fMOST high-resolution 3D reconstruction system is not limited to the central nervous system,but can be extended to the morphological study of multiple visceral nervous systems.

Andrographolide sulfonate (AS) is a sulfonated derivative of andrographolide extracted from Andrographis paniculata (Burm.f.) Nees, and has been approved for several decades in China. The present study aimed to investigate the novel therapeutic application and possible mechanisms of AS in the treatment of rheumatoid arthritis. Results indicated that administration of AS by injection or gavage significantly reduced the paw swelling, improved body weights, and attenuated pathological changes in joints of rats with adjuvant-induced arthritis. Additionally, the levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1β in the serum and ankle joints were reduced. Bioinformatics analysis, along with the spleen index and measurements of IL-17 and IL-10 levels, suggested a potential relationship between AS and Th17 cells under arthritic conditions. In vitro, AS was shown to block Th17 cell differentiation, as evidenced by the reduced percentages of CD4⁺ IL-17A⁺ T cells and decreased expression levels of RORγt, IL-17A, IL-17F, IL-21, and IL-22, without affecting the cell viability and apoptosis. This effect was attributed to the limited glycolysis, as indicated by metabolomics analysis, reduced glucose uptake, and pH measurements. Further investigation revealed that AS might bind to hexokinase2 (HK2) to down-regulate the protein levels of HK2 but not glyceraldehyde-3-phosphate dehydrogenase (GAPDH) or pyruvate kinase M2 (PKM2), and overexpression of HK2 reversed the inhibition of AS on Th17 cell differentiation. Furthermore, AS impaired the activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signals in vivo and in vitro, which was abolished by the addition of lactate. In conclusion, AS significantly improved adjuvant-induced arthritis (AIA) in rats by inhibiting glycolysis-mediated activation of PI3K/AKT to restrain Th17 cell differentiation.
Animals ; Th17 Cells/immunology* ; Diterpenes/pharmacology* ; Arthritis, Rheumatoid/metabolism* ; Proto-Oncogene Proteins c-akt/immunology* ; Glycolysis/drug effects* ; Cell Differentiation/drug effects* ; Phosphatidylinositol 3-Kinases/genetics* ; Rats ; Male ; Rats, Sprague-Dawley ; Humans ; Andrographis paniculata/chemistry* ; Arthritis, Experimental/drug therapy* ; Interleukin-17/immunology* ; Signal Transduction/drug effects*