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 analyze the RHD genotyping and sequencing results of RhD serology negative samples in the clinic, and to further explore the laboratory methods for RhD detection, in order to provide a basis for clinical precision blood transfusion. METHODS: A total of 27 200 whole blood samples were screened for RhD blood group antigen using microcolumn gel card method.Serologic RhD-negative confirmation tests were performed on blood samples that were negative for RhD on initial screening using three different clonal strains of IgG anti-D reagents. The 10 exons of the RHD gene on chromosome 1 were also analyzed by PCR-SSP to determine RHD genotyping.When the PCR-SSP method did not yield definitive results, the RHD gene of the sample was analyzed by the third-generation sequencing. RESULTS: The results of the initial screening test by the microcolumn gel card method showed that 136 of the 27 200 samples were RhD-negative, of which 86 underwent RhD-negative confirmation testing and RHD genotyping, 88.37% (76/86 cases) of the RhD-negative confirmation test results were negative for the three anti-D reagents, and the results of RHD genotyping showed that 67.44% (58/86 cases) of the cases had a complete deletion of 10 exons, and the remaining 28 cases were RHD*711delC (1 case), RHD*D-CE(1-9)-D (1 case), RHD*D-CE(2-9-)D (2 cases), RHD*D-CE(3-9)-D (4 cases), RHD*DEL1 (c.1227G >A) mutation (16 cases), RHD*weak partial 15(845G >A) mutation (3 cases), and a mutation of c.165C >T base was found in 1 sample by three-generation sequencing. CONCLUSION RHD genotype testing of samples that are serologically negative for RhD antigen shows that some of the samples have RHD gene variants, not all of which are total deletions of RHD, suggesting that there are some limitations of the serologic method for RhD detection. Due to the polymorphism of the RHD gene structure, different RhD variants present different serologic features, which need to be further detected in combination with molecular biology testing, especially for the identification of Asian-type DELs, which is important for clinical precision blood transfusion.
Humans ; Rh-Hr Blood-Group System/genetics* ; Genotype ; Polymerase Chain Reaction ; Exons ; Blood Grouping and Crossmatching

Objective To investigate the effect and mechanism of lycium barbarum polysaccharide(LBP)on hepatocyte injury induced by homocysteine(Hcy).Methods Normal C3H/An mouse hepatocytes(NCTC 1469)were cultured in vitro and treated with different concentrations of Hcy(0,50,100,200,500 μmol/L).The optimal concentrations of Hcy-treated NCTC 1469 cells were detected by MTT assay.When the cells reached the logarithmic growth stage,the conditions were set up as follows:(1)control group(cultured with DMEM medium supplemented with 10%horse serum)and Hcy group(treated with 100 μmol/L Hcy solution for 48 h),and the cells were collected.Cell viability staining was used to detect apoptosis,aspartate aminotransferase(AST)/alanine aminotransferase(ALT)activity detection kit was used to detect AST and ALT activities,RT-qPCR was used to detect the expression levels of YAP1,DNMT1,DNMT3a and DNMT3b mRAN,and Western blotting was used to detect the expression of YAP1 protein,nested methylation specific PCR(nMS-PCR)was used to detect DNA methylation rates in the YAP1 promoter region.(2)Control group,LBP group,Hcy group and Hcy+LBP group.LBP group was treated with 4 mg/ml LBP solution for 2 h,Hcy group and Hcy+LBP group were treated with 100 μmol/L Hcy solution for 48 h,and Hcy+LBP group was treated with 4 mg/ml LBP solution at 46 h,and the cells were collected.The expression levels of YAP1,DNMT1,DNMT3a and DNMT3b mRAN were detected by RT-qPCR;the expression of YAP1,Bax and Bcl-2 proteins was detected by Western blotting;AST/ALT activity detection kit was used to detect AST and ALT activities.Prediction of DNA methylation CpG islands in YAP1 promoter region by bioinformatics.Results NCTC 1469 cells were treated with 100 μmol/L Hcy according to the results of MTT assay.Compared with control group,the apoptosis rate of Hcy group increased(P<0.01),the activities of ALT and AST increased(P<0.001),the mRAN and protein expression levels of YAP1 decreased(P<0.001),and the methylation rate of YAP1 promoter region increased(P<0.01),the mRNA expression levels of DNMT1,DNMT3a and DNMT3b increased(P<0.01 or P<0.001).Compared with Hcy group,the mRNA expression levels of DNMT1,DNMT3a and DNMT3b in the Hcy+LBP group decreased(P<0.001),the mRAN and protein expression levels of YAP1 significantly increased(P<0.01 or P<0.001).In addition,in the Hcy+LBP group,cells showed significantly elevated of Bcl-2 protein(P<0.001),but decreased Bax protein(P<0.001),and decreased activities of ALT and AST(P<0.001).Conclusions The decrease of YAP1 expression may be the key process of Hcy induced injury of NCTC 1469 cells,and the methylation of the YAP1 promoter region may be the molecular mechanism of Hcy induced YAP1 expression change.LBP may improve NCTC 1469 cell damage induced by Hcy by positively regulating YAP1 expression.

By using thioflavin T(ThT)as displacement-based fluorescent probes,three kinds of aptasensors were constructed for rapid detection of three kinds of small molecules such as ochratoxin A(OTA),aflatoxin B1(AFB1)and adenosine.In the absence of target molecule,ThT bound with the aptamer to form an aptamer-ThT complex and exhibited a significant fluorescence response.Upon the addition of target molecule,because of the higher affinity between target and aptamer than that between ThT and the aptamer,ThT was displaced by the target molecule from the aptamer-ThT complex,resulting in weakened fluorescence signal.Based on this principle,the target molecule could be detected quantitatively.Further study through circular dichroism spectra showed that there was no significant change in the conformation of the aptamer after addition of ThT or target molecules.The stoichiometric ratios of ThT to OTAapt,AFB1apt and Adeapt measured through the method of equimolar continuous variation was 1∶1,1∶1 and 2∶1,respectively,and their dissociation constants were all larger than those between the target molecule and its aptamer.Therefore,the principle of this detection method was the displacement of fluorescent probe(ThT)in aptamer-ThT complex by target molecule,resulting in decrease of fluorescence intensity.Under optimal experimental conditions,the limits of detection(LODs)were 0.8 nmol/L for OTA,1.3 nmol/L for AFB1,and 0.10 μmol/L for adenosine,respectively.This method was label-free,simple to operate,with low cost,good selectivity and high sensitivity.The developed assay kit based on this method could be used for actual sample detection.

Objective To investigate the relationship of miRNA gene polymorphisms with blood pressure(BP)responses to the sodium and potassium diet intervention.Methods In 2004,we recruited 514 participants from 124 families in seven villages of Baoji,Shaanxi Province,China.All subjects were given a three-day normal diet,followed by a seven-day low-salt diet,a seven-day high-salt diet,and finally a seven-day high-salt and potassium supplementation.A total of 19 miRNA single nucleotide polymorphisms(SNPs)were selected for analysis.Results Throughout the sodium-potassium dietary intervention,the BP of the subjects fluctuated across all phases,showing a decrease during the low-salt period and an increase during the high-salt period,followed by a reduction in BP subsequent to potassium supplementation during the high-salt diet.MiR-210-3p SNP rs 12364149 was significantly associated with systolic BP(SBP),diastolic BP(DBP)and mean arterial pressure(MAP)responses to low-salt diet.MiR-4638-3p SNP rs6601178 was significantly associated with SBP while miR-26b-3p SNP rs115254818 was significantly associated with MAP responses to low-salt intervention.In addition,miR-26b-3p SNP rs115254818 was significantly correlated with SBP,DBP and MAP responses to high-salt intervention.MiR-1307-5p SNPs rs1 1191676 and rs2292807 were associated with SBP and MAP responses to high-salt diet.MiR-4638-3p SNP rs6601178,miR-210-3p SNP rs12364149,miR-382-5p SNP rs4906032 and rs4143957 were significantly associated with SBP response to high-salt diet.In addition,miR-26b-3p SNP rs115254818 was significantly associated with SBP,DBP and MAP responses to potassium supplementation.MiR-1307-5p SNPs rs11191676,rs2292807,and miR-19a-3p SNP rs4284505 were significantly associated with SBP responses to high-salt and potassium supplementation.Conclusion miRNA gene polymorphisms are associated with BP response to sodium and potassium,suggesting that miRNA genes may be involved in the pathophysiological process of salt sensitivity and potassium sensitivity.

Objective: To study the effect and regulatory mechanism of secreted proteins from PSC on pancreatic ductal adenocarcinoma cells(PANC-1). Methods: Conditioned medium(CM) from pancreatic stellate cells(PSC) was collected through an indirect co-culture method, and PANC-1 cells were cultured separately with CM for 0, 2, and 24 h. The proliferation phenotype of PANC-1 cells under different stimulation periods was detected using the CCK-8 assay. Proteomic analysis was performed to analyze the changes in protein levels of PANC-1 cells, and the most significant protein changes were validated using Western blot. Results: Compared with the control group, the proliferation rate of PANC-1 cells increased after being stimulated by PSC derived CM; The results of proteomic analysis showed that the protein expression of metabolic pathways in PANC-1 cells increased continuously after being cultured in PSC CM for 0, 2, and 24 h. Western blot analysis confirmed an increasing trend of PIK3C2A in PANC-1 cells, indicating that the CM from PSC might promote the proliferation of PANC-1 cells by upregulating the expression of PIK3C2A. Conclusion The CM of PSC may promote the proliferation of PANC-1 cells by upregulating the expression of PIK3C2A, which improves the understanding of the mechanism of interaction between PSCs and pancreatic cancer cells in the tumor microenvironment.

AIM To study the protective effects and mechanism of pueraria isoflavones on myocardial injury in ovariectomized rats.METHODS Thirty-six rats were randomly divided into the sham operation group,the model group,the estradiol valerate group(0.1 mg/kg)and the low,medium and high dose pueraria isoflavones groups(55,110,220 mg/kg).In contrast to the rats of the sham operation group having their small pieces of adipose tissue removal around the ovaries,rats of the other groups had their bilateral ovaries excised,followed by the 16-week corresponding oral drug administration 2 weeks later at a once daily frequency for,6 days a week.At the end of the 16th week,the rats had their hemodynamics[systolic pressure(SBP),diastolic pressure(DBP),mean pressure(MBP),left ventricular systolic pressure(LVSP),left ventricular diastolic pressure(LVMP),and the maximum rate of increase and decrease of left ventricular pressure during isovolumic contraction(±dp/dtmax)]detected by PowerLab;their cardiac pathological changes observed by HE staining;their levels of creatine kinase(CK),lactate dehydrogenase(LDH),total cholesterol(TC),triglyceride(TG),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C)and glucose(Glu)in plasma detected by biochemical analyzer;their myocardial level of adenosine triphosphate(ATP)detected by colorimetry;their mRNA expressions of glucose transporter 4(GLUT4),lactate dehydrogenase A(LDHA),carnitine palmitoyl transferase-1(CPT-1α),acyl coenzyme A carboxylase(ACC),liver kinase B1(LKB1),adenylate-activated protein kinase(AMPK)and peroxisome proliferator-activated receptor γ coactivator factor 1α(PGC-1α)detected by RT-qPCR;and their myocardial expressions of energy metabolism related proteins LKB1,p-AMPK/AMPK and PGC-1α detected by Western blot.RESULTS Compared with the model group,the pueraria isoflavones groups displayed decreased levels of SBP,DBP,MBP,LVSP,LVMP(P＜0.05,P＜0.01);increased-dp/dtmax(P＜0.05,P＜0.01);improved myocardial fibrinolysis,gap widening and inflammatory infiltration caused by ovariectomy;decreased activities of LDH and CK(P＜0.05);increased myocardial ATP level(P＜0.05,P＜0.01);decreased levels of TC,TG,LDL-C and Glu(P＜0.05,P＜0.01);increased HDL-C level(P＜0.05,P＜0.01);increased myocardial mRNA expressions of GLUT4,LDHA,CPT-1α,ACC,LKB1,AMPK and PGC-1α(P＜0.05,P＜0.01);and increased protein expressions of myocardial LKB1,p-AMPK/AMPK and PGC-1α(P＜0.05,P＜0.01).CONCLUSION Pueraria isoflavones are protective to myocardial injury in ovariectomized rats,and the mechanism may lie in the improvement of energy metabolism-related myocardial proteins via LKB1/AMPK/PGC-1α signaling pathway.

Objective:After initially establishing a health performance evaluation index system for county health alliance,this study aimed to calculate the weight coefficients of various indicators and dimensions through the entropy weight method,which provided an evaluation orientation for county health alliance to achieve health-centered sustainable development.Methods:Based on existing research,the entropy weight method was used to standardize and calculate the weights of 27 indicators from five sample regions.Results:The weight coefficients for the three dimensions of construction structure,organizational process,and health outcomes are 0.261,0.301,and 0.439,respectively.In the construction structure dimension,the weight coefficients for inside-county medical utilization rate(0.105)and the proportion of outpatient and emergency visits in primary healthcare institutions inside-county(0.048)are relatively high.In the organizational process dimension,the weight coefficients for standardized management service rates for hypertension at the primary health care(0.062)and diabetes control rates(0.050)are relatively high.In the health outcome dimension,the weight coefficients for the low birth weight rate(0.072)and life expectancy(0.051)are relatively high.Conclusions:The weight coefficients of the health performance evaluation indicators for county health alliance calculated based on the entropy weight method highlighted the important role of health outcomes,as well as objectively reflect the contribution of each evaluation index to the health performance of the county health alliance.