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.

The Model for End-Stage Liver Disease （MELD） score is currently used to prioritize liver allocation for cirrhotic patients awaiting liver transplantation in the world. With the application of MELD score in transplantation for patients with severe conditions， several models have been proposed to refine and improve MELD score. MELD score has also been used for the management of non-transplantation patients with chronic liver disease. This article briefly reviews the background of these models and believes that the original intention of MELD is to determine the priority of organ allocation for liver transplantation. The expanded application of MELD score beyond liver transplantation assessment should be performed with reference to clinical practice， and different MELD models should be selected rationally based on individual conditions， in order to help patients achieve optimal prognosis assessment， intervention measures， and benefits.

We investigated the prevalence and spatial distribution characteristics of T.gondii infection in cats in China,to provide a scientific basis for the prevention and con-trol of T.gondii.We searched PubMed,CNKI,Wanfang Da-tabase,and Baidu Academic Database to retrieve studies on the seroprevalence of T.gondii in domestic cats published by December 31,2023,in China,to investigate the spatial loca-tion and expression of T.gondii infection in China by using Geographical Information Systems(GIS).SPSS 26.0 software was used for statistical analysis.A total of 86 eligible studies published between 1984 and 2023 were included in this study,covering 28 provincial administrative regions and involving 20 722 cats.The ArcGIS classification results indicated that the overall positivity rate of T.gondii in domestic cats was 14.78％(3 080/20 836,95％CI:14.07％-15.03％).No epidemiological study of T.gondii infection in cats has been reported in Tibet,Tianjin,Hainan,Hong Kong,Ma-cao,or Taiwan.The prevalence of T.gondii infection in cats was highest in Shanxi Province(60％,54/90,95％CI:49.82％-70.18％),followed by Hebei Province(57.33％,43/75,95％CI:46.07％-68.59％),Henan Province(45.53％,173/380,95％CI:46.07％-68.59％),and Yunnan Province(43.64％,24/55,95％CI:30.49％-56.79％).The lowest seroprevalence of T.gondii antibody was found in Jiangxi Province(2.47％,2/81,95％CI:-0.90％-5.90％).Furthermore,the seropreva-lence of T.gondii in cats in northern China was 14.12％(2 044/14 491 95％CI:12.34％-15.90％),whereas that in southern China was 16.30％(1 036/6 355 95％CI:15.40％-17.20％).Significant differences were observed between them(x2=16.60,P＜0.05).The temporal distribution results indicated a decrease in the overall seroprevalence of T.gondii in cats in China from 1984 to 2023.Our findings suggested that T.gondii in cats is widespread in China,with a stable epidemic cycle,and the rates of Toxoplasma positivity vary greatly among regions.The increasing prevalence of pet cats in China,and the close rela-tionship between these cats and humans,may pose substantial exposure risks to a large susceptible population.Therefore,the association between cat ownership and T.gondii infection in humans,and how to decrease human environmental contamination through cat exposure to T.gondii and T.gondii oocysts,requires further investigation.

Objective:To analyze the equity of Traditional Chinese medicine(TCM)human resource allocation across 31 provinces in China and explore its influencing pathways,aiming to provide scientific reference for optimizing the allocation of TCM human resources.Methods:The Health Resource Density Index(HRDI)was employed to measure the equity of TCM human resource allocation in China,and the fuzzy-set qualitative comparative analysis(fsQCA)was utilized to explore the configurational pathways influencing this equity.Results:Based on the data from 2021,the HRDI of TCM human resources in China exhibited significant regional disparities,manifesting as a distribution pattern of"high in the east and low in the west."Three pathways promoting high equity were identified:the internal-external balance-driven pathway(H1),the economy-demand co-driven pathway(H2),and the government-led driving pathway(H3).Meanwhile,three pathways leading to low equity were also recognized:the economy-demand constraint pathway(L1)and the internal-external constraint pathways(L2、L3).Conclusion:There are notable regional disparities in the equity of TCM human resource allocation in China,with multiple factors jointly influencing this equity,among which population density serves as a core factor.In subsequent efforts to enhance equity,it is advisable to consider optimizing the synergies among multiple factors and implementing precise policies for different regions to promote efficient allocation and balanced development of TCM human resources.

BACKGROUND: Hepatocytes are an attractive cell source in hepatic tissue engineering because they are the primary cells of the liver, maintaining liver homeostasis through their intrinsic function. Due to the increasing demand for liver donors, a wide range of methods are being studied to obtain functionally active hepatocytes. iPSCs are one of the alternative cell sources, which shows great promise as a tool for generating hepatocytes. METHODS: This study determined whether factors associated with iPSCs contributed to variation in hepatocyte-like cells derived from iPSCs. The factors of concern for the iPSCs included the culture system, the source of iPSCs, and cell seeding density for initiating the differentiation. RESULTS: Our results found iPSC-dependent variances among differentiated hepatocyte-like cells. The matrix used in culturing iPSCs significantly impacts cell morphologies, characteristics, and the expression of pluripotent genes, such as OCT4 and SOX2, varied in iPSCs derived from different sources. These characteristics, in turn, play a consequential role in determining the functional activity of the iPSC-derived hepatocyte-like cells. In addition, cell seeding density was observed to be an essential factor for the efficient generation of iPSC-derived hepatocyte-like cells, with 2- 4 * 10 cells/cm of seeding density resulting in good morphology and functionality. CONCLUSION This study provides the baseline of effective differentiation protocols for iPSC-derived hepatocyte-like cells with the appropriate conditions, including cell culture media, iPSC source, and the seeding density of iPSCs.

Wnt/β-catenin is a signaling pathway associated with embryonic development, organ formation, cancer, and fibrosis. Its activation can repair kidney damage during acute kidney injury (AKI) and accelerate the occurrence of renal fibrosis after chronic kidney disease (CKD). Interestingly, p53 has also been found as a key modulator in AKI and CKD in recent years. Meantime, some studies have found crosstalk between Wnt/β-catenin signaling pathways and p53, but more evidence is required on whether they have synergistic effects in renal disease progression. This article reviews the role and therapeutic targets of Wnt/β-catenin and p53 in AKI and CKD and proposes for the first time that Wnt/β-catenin and p53 have a synergistic effect in the treatment of renal injury.

Objective:To examine the application of a novel pedagogical approach multidimensional supportive psychological intervention(MSPI)in the clinical practice teaching of andrological nursing care.Methods:Using the Hamilton Depression Scale(HAMD),we assessed the psychology of 100 nursing interns about to enter clinical practice in the Department of Andrology from De-cember 2021 to December 2022.We equally randomized the subjects into an experimental and a control group,the former receiving MSPI and the latter trained on the conventional teaching model without any psychological support intervention.Results:Compared with the baseline,the HAMD scores were significantly decreased in the experimental group after intervention(12.4±2.1 vs 8.9±2.4,P＜0.01),but increased in the controls(13.1±1.8 vs 14.7±1.9,P＜0.01);the skill scores dramatically increased in the experimental group(82.6±4.7 vs 91.2±2.4,P＜0.01),but decreased in the control group after intervention(81.0±3.5 vs 80.4±2.7,P=0.28).Conclusion:MSPI can significantly enhance the learning enthusiasm of nursing students in a short period,re-duce their psychological stress and improve teaching outcomes.This approach,combining psychology with teaching,can also strength-en the mental resilience of nursing students and better confront them with future professional challenges.

AIM To optimize the extraction process for Jigen Standard Decoction,and to establish its quality standard.METHODS With soaking time,water addition and first decoction time as influencing factors,comprehensive score for 3,6'-disinapoyl sucrose content and yield rate as an evaluation index,the extraction process was optimized by response surface method on the basis of single factor test.The content and transfer rate of 3,6'-dimustayl sucrose were determined,after which HPLC characteristic chromatograms were established,cluster analysis,principal component analysis and orthogonal partial least squares discriminant analysis were performed.RESULTS The optimal conditions were determined to be 60 min for soaking time,(12+11)times for water addition,and(47+20)min for decoction time,the comprehensive score was 97.98.Fifteen batches of standard decoctions demonstrated the average yield rate and transfer rate of 14.182％and 20.468％,respectively,whose characteristic chromatograms existed six common peaks with the similarities of more than 0.9(except for S4,S8).Various batches of standard decoctions were clustered into two types,three principal components displayed the acumulative variance contribution rate of 91.4％,peaks 2,6 were quality markers.CONCLUSION This precise,stable and reproducible method can be used for the preparation and quality control of Jigen Standard Decoction.

Objective:To analyze the correlation among human retinol binding protein 4(RBP4),miR-1-3p,re-combinant human vitamin D binding protein(VDBP)and severity of ST-segment elevation myocardial infarction(STEMI)based on SYNTAX score and their diagnostic value for it.Methods:A total of 162 STEMI patients admit-ted to our hospital for treatment from January 2020 to June 2021 were selected as STEMI group,and another 67 healthy subjects who received physical examination in our hospital simultaneously were selected as healthy control group.According to SYNTAX score,STEMI group was further divided into low risk group(n=68,＜22 points),medium risk group(n=53,23 points≤SYNTAX score≤32 points)and high risk group(n=41,＞33 points).Lev-els of RBP4,VDBP and miR-1-3p expression were compared among above groups.Diagnostic value of single and combined detection of above indexes for severity of STEMI were analyzed.Correlation between SYNTAX score and above indexes were analyzed in STEMI patients.Results:Compared with healthy control group,there were signifi-cant rise in levels of RBP4[(47.18±5.24)μg/L vs.(81.40±6.11)μg/L]and VDBP[(2.36±0.75)μg/ml vs.(3.55±1.04)μg/ml],and significant reduction in miR-1-3p expression[(1.18±0.13)vs.(0.72±0.07)]in STEMI group,P＜0.001 all.Compared with low risk group,there were significant rise in levels of RBP4[(69.97±2.98)μg/L vs.(85.23±3.76)μg/L vs.(95.41±3.16)μg/L]and VDBP[(3.19±0.50)μg/ml vs.(3.55±0.52)μg/ml vs.(4.16±0.64)μg/ml],and significant reduction in miR-1-3p expression[(0.80±0.05)vs.(0.70±0.04)vs.(0.61±0.03)]in medium risk group and high risk group,and levels of RBP4 and VDBP in high risk group were significantly higher than those of medium risk group,miR-1-3p expression in high risk group was significantly lower than that of medium risk group(P＜0.001 all).ROC analysis indicated that area under the curve(AUC)of combined detection of above indexes was 0.892,which was significantly higher than each single detection(Z=4.787,3.078,2.495,P＜0.05 or＜0.01).Spearman correlation analysis indicated that STEMI severity was significant positively correlated with levels of RBP4 and VDBP(r=0.849,0.776,P＜0.001 both),and significant inversely correla-ted with miR-1-3p expression(r=-0.790,P＜0.001).Conclusion:Levels of RBP4 and VDBP,and miR-1-3p ex-pression can reflect severity of STEMI patients.Triple combined detection possesses high diagnostic efficacy for disease se-verity,which can be used as clinical important indexes for assessing patient's condition.

Objective To design a novel oxygenator to solve the existing problems of extracorporeal membrane oxygenation(ECMO)machine in high transmembrane pressure difference,low efficiency of blood oxygen exchange and susceptibility to thrombosis.Methods The main body of the oxygenator vascular access flow field was gifted with a flat cylindrical shape.The topology of the vascular access was modeled in three dimensions,and the whole flow field was cut into a blood inlet section,an inlet buffer,a heat exchange zone,a blood oxygen exchange zone,an outlet buffer and a blood outlet section.The oxygenator was compared with Quadrox oxygenator by means of ANSYS FLUENT-based simulation and prototype experiments.Results Simulation calculations showed the oxygenator designed was comparable to the clinically used ones in general,and gained advantages in transmembrane pressure difference,blood oxygen exchange and flow uniformity.Experimental results indicated that the oxygenator behaved better than Quadrox oxygenator in transmembrane pressure difference and blood oxygen exchange.Conclusion The oxygenator has advantages in transmem-brane pressure difference,temperature change,blood oxygen ex-change and low probability of thrombosis.[Chinese Medical Equipment Journal,2024,45(3):23-28]