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:Conduct an in-depth investigation into the current status and development needs of infectious disease clinical testing at medical institutions at all levels across the country.Methods:A cross-sectional survey was carried out from January 5, 2023, to June 1, 2023, using a web-based questionnaire distributed to healthcare organizations at all levels nationwide. A total of 3 462 questionnaires were collected, and after quality control and a no-return random sampling process, 2 778 questionnaires were included in the analysis. The research covered basic information about medical institutions, the current emergency response capacity of infectious disease laboratories, the status of the implementation of statutory infectious diseases, the demand for infectious disease testing programs, and the reasons for any lack of implementation. Additionally, the study further analyzed the participation rates of medical institutions at all levels, laboratory accreditation, the presence of infectious disease testing departments, and the testing rates for major infectious diseases.Results:Among the 2 778 questionnaires, the proportions of tertiary, secondary, and primary hospitals were 39.13% (1 087/2 778), 53.20% (1 478/2 778) and 4.46% (124/2 778), respectively. The proportion of specialized infectious disease medical institutions was 8.89% (247/2 778). The proportion of medical institutions with laboratory accreditation was 12.92% (359/2 778). The proportion of clinical laboratory performing infectious disease testing was 98.56% (2 738/2 778). Among the infectious disease pathogens included in the analysis, the implementation rates of testing related to hepatitis B virus, hepatitis C virus, 2019-nCoV, human immunodeficiency virus, and syphilis spirochete were 97.62% (2 712/2 778), 94.85% (2 635/2 778), 93.27% (2 591/2 778), 96.33% (2 676/2 778) and 96.22% (2 673/2 778), respectively. In the research on the demand for clinical infectious disease pathogen testing, the demand for testing of Brucella spp. bacteria and Mycobacterium tuberculosis was 25.50% (90/353) and 8.22% (29/353), respectively. The main factors that did not meet the demand for clinical infectious disease testing were the lack of space in the laboratory to carry out the tests, insufficient manpower, and the absence of a fee schedule, accounting for 44.10% (1 225/2 778), 42.55% (1 182/2 778) and 36.00% (1 000/2 778), respectively.Conclusions:Clinical testing for infectious diseases in our country is mainly carried out in the laboratories of tertiary and secondary medical institutions, which can adequately meet the laboratory testing needs for common infectious diseases. However, there are situations such as limited infectious disease testing projects and insufficient spatial, human, and material resources. Improvements in laboratory construction and methodology can be made according to the actual conditions of each region.

Objective:Conduct an in-depth investigation into the current status and development needs of infectious disease clinical testing at medical institutions at all levels across the country.Methods:A cross-sectional survey was carried out from January 5, 2023, to June 1, 2023, using a web-based questionnaire distributed to healthcare organizations at all levels nationwide. A total of 3 462 questionnaires were collected, and after quality control and a no-return random sampling process, 2 778 questionnaires were included in the analysis. The research covered basic information about medical institutions, the current emergency response capacity of infectious disease laboratories, the status of the implementation of statutory infectious diseases, the demand for infectious disease testing programs, and the reasons for any lack of implementation. Additionally, the study further analyzed the participation rates of medical institutions at all levels, laboratory accreditation, the presence of infectious disease testing departments, and the testing rates for major infectious diseases.Results:Among the 2 778 questionnaires, the proportions of tertiary, secondary, and primary hospitals were 39.13% (1 087/2 778), 53.20% (1 478/2 778) and 4.46% (124/2 778), respectively. The proportion of specialized infectious disease medical institutions was 8.89% (247/2 778). The proportion of medical institutions with laboratory accreditation was 12.92% (359/2 778). The proportion of clinical laboratory performing infectious disease testing was 98.56% (2 738/2 778). Among the infectious disease pathogens included in the analysis, the implementation rates of testing related to hepatitis B virus, hepatitis C virus, 2019-nCoV, human immunodeficiency virus, and syphilis spirochete were 97.62% (2 712/2 778), 94.85% (2 635/2 778), 93.27% (2 591/2 778), 96.33% (2 676/2 778) and 96.22% (2 673/2 778), respectively. In the research on the demand for clinical infectious disease pathogen testing, the demand for testing of Brucella spp. bacteria and Mycobacterium tuberculosis was 25.50% (90/353) and 8.22% (29/353), respectively. The main factors that did not meet the demand for clinical infectious disease testing were the lack of space in the laboratory to carry out the tests, insufficient manpower, and the absence of a fee schedule, accounting for 44.10% (1 225/2 778), 42.55% (1 182/2 778) and 36.00% (1 000/2 778), respectively.Conclusions:Clinical testing for infectious diseases in our country is mainly carried out in the laboratories of tertiary and secondary medical institutions, which can adequately meet the laboratory testing needs for common infectious diseases. However, there are situations such as limited infectious disease testing projects and insufficient spatial, human, and material resources. Improvements in laboratory construction and methodology can be made according to the actual conditions of each region.

Objective To investigate the relationship between high DNA stainability(HDS)and routine semen parameters.Methods Semen samples were collected from 396 men of childbearing age who were admitted to our department.Correlations of HDS with routine semen parameters and age were analyzed.Multiple linear regression analysis was performed to identify the routine semen parameters that had the greatest influence on HDS.The correlation of HDS and DNA fragmentation index(DFI)with routine semen parameters and age in 244 patients with teratozoospermia was analyzed.The 244 patients were divided into extremely severe,severe,moderate,and mild teratozoospermia groups,and differences in HDS,DFI,and routine semen parameters were compared among the four groups.Results HDS was negatively correlated with total sperm count,sperm concentration,sperm progressive motility,and normal sperm morphology rate(NSMR)(P<0.01).After adjusting for potential confounders,including total sperm count,sperm concentration,sperm progressive motility,NSMR,and DFI,NSMR had the most significant negative effect on HDS(P<0.05).In the 244 patients with teratozoospermia,HDS was negatively correlated with NSMR(P<0.01)and positively correlated with the percentage of sperm head and tail abnormalities(P<0.05),while DFI was positively correlated with the percentage of sperm tail abnormalities(P<0.01).There was a significant difference in the percentage of sperm head abnormalities among the four teratozoospermia groups.The more severe the malfor-mation,the higher the percentage of sperm head abnormalities was(P<0.001).HDS in the extremely severe teratozoospermia group was significantly higher than that in the mild and moderate teratozoospermia groups(P<0.05).No significant differences in DFI were found among the four groups(P>0.05).Conclusion HDS was closely correlated with routine semen parameters and was a crucial biomarker for assessing sperm quality,particularly the extent of sperm head abnormalities.

Objective To propose a low-dose CT image denoising method based on an improved Corediff model to recover the detailed features of the image and enhance the image quality.Methods An RS-Corediff model was established by modifying the key component U-Net network of the Corediff model.Firstly,the residual module was introduced in the network input stage for feature extraction;secondly,a new downsampling module was designed in the U-Net network encoder,which learned the semantic information of the feature map by convolution and maintained the learning state during the downsampling process so as to fully extract the image features;thirdly,the feature splicing processing was used to further enhance the learning effect during the upsampling process of the U-Net network decoder;finally,the convolutional kernel size was modified to adjust the sensory field during the convolutional process of the whole U-Net network structure so as to obtain rich features.The RS-Corediff model was compared with the residual encoder-decoder convolutional neural network(RED-CNN)model and the Corediff model on the public dataset AAPM 2016 in order to verify its effectiveness for low-dose CT image denoising.Results The RS-Corediff model gained advantages over the RED-CNN and Corediff models with a peak signal-to-noise ratio(PSNR)of 41.269 8,structural similarity(SSIM)of 0.953 4 and root mean square error(RMSE)of 17.568 7.Conclusion The proposed method effectively preserves the texture and details of low-dose CT images during the denoising process to improve the overall quality of the images.[Chinese Medical Equipment Journal,2025,46(5):9-13]

Objective To investigate the relationship between high DNA stainability(HDS)and routine semen parameters.Methods Semen samples were collected from 396 men of childbearing age who were admitted to our department.Correlations of HDS with routine semen parameters and age were analyzed.Multiple linear regression analysis was performed to identify the routine semen parameters that had the greatest influence on HDS.The correlation of HDS and DNA fragmentation index(DFI)with routine semen parameters and age in 244 patients with teratozoospermia was analyzed.The 244 patients were divided into extremely severe,severe,moderate,and mild teratozoospermia groups,and differences in HDS,DFI,and routine semen parameters were compared among the four groups.Results HDS was negatively correlated with total sperm count,sperm concentration,sperm progressive motility,and normal sperm morphology rate(NSMR)(P<0.01).After adjusting for potential confounders,including total sperm count,sperm concentration,sperm progressive motility,NSMR,and DFI,NSMR had the most significant negative effect on HDS(P<0.05).In the 244 patients with teratozoospermia,HDS was negatively correlated with NSMR(P<0.01)and positively correlated with the percentage of sperm head and tail abnormalities(P<0.05),while DFI was positively correlated with the percentage of sperm tail abnormalities(P<0.01).There was a significant difference in the percentage of sperm head abnormalities among the four teratozoospermia groups.The more severe the malfor-mation,the higher the percentage of sperm head abnormalities was(P<0.001).HDS in the extremely severe teratozoospermia group was significantly higher than that in the mild and moderate teratozoospermia groups(P<0.05).No significant differences in DFI were found among the four groups(P>0.05).Conclusion HDS was closely correlated with routine semen parameters and was a crucial biomarker for assessing sperm quality,particularly the extent of sperm head abnormalities.

Objective To propose a low-dose CT image denoising method based on an improved Corediff model to recover the detailed features of the image and enhance the image quality.Methods An RS-Corediff model was established by modifying the key component U-Net network of the Corediff model.Firstly,the residual module was introduced in the network input stage for feature extraction;secondly,a new downsampling module was designed in the U-Net network encoder,which learned the semantic information of the feature map by convolution and maintained the learning state during the downsampling process so as to fully extract the image features;thirdly,the feature splicing processing was used to further enhance the learning effect during the upsampling process of the U-Net network decoder;finally,the convolutional kernel size was modified to adjust the sensory field during the convolutional process of the whole U-Net network structure so as to obtain rich features.The RS-Corediff model was compared with the residual encoder-decoder convolutional neural network(RED-CNN)model and the Corediff model on the public dataset AAPM 2016 in order to verify its effectiveness for low-dose CT image denoising.Results The RS-Corediff model gained advantages over the RED-CNN and Corediff models with a peak signal-to-noise ratio(PSNR)of 41.269 8,structural similarity(SSIM)of 0.953 4 and root mean square error(RMSE)of 17.568 7.Conclusion The proposed method effectively preserves the texture and details of low-dose CT images during the denoising process to improve the overall quality of the images.[Chinese Medical Equipment Journal,2025,46(5):9-13]

Thrombosis is a key factor that increases the mortality rate of COVID-19 patients and causes long COVID sequelae. Guanxinning Tablet (GXNT), which is composed of Salvia miltiorrhiza and Ligusticum Chuanxiong, has significant antithrombotic activity, but the similarities and differences between its anti-conventional thrombus and microthrombus induced by COVID-19 remain unclear. In this paper, the main active components, potential targets and mechanisms of GXNT in the treatment of thrombus and microthrombus caused by COVID-19 were preliminarily revealed by using anti-platelet experiments in vitro, network pharmacology analysis, molecular docking technology and molecular biology experiments. The results of platelet aggregation and adhesion experiments in vitro showed that GXNT had significant anti-platelet aggregation and adhesion activities in a dose-dependent manner. Using network pharmacology analysis, it was revealed that salvianolic acid B, tanshinone IIA, caffeic acid and ligustrazine in GXNT could resist thrombus and microthrombus caused by COVID-19 through key targets as the high mobility group box 1 protein (HMGB1), tumor necrosis factor (TNF), interleukin 6 (IL6) and AKT serine/threonine kinase 1 (AKT1). HMGB1 signaling pathway is one of its key common mechanisms. Western blot also indicated that GXNT significantly inhibited the expression of HMGB1 protein in platelets. In summary, this paper explores the similarities and differences between the mechanism of GXNT against conventional thrombus and microthrombus caused by COVID-19 and provides drug reference and theoretical basis for clinical prevention and treatment of long COVID sequelae. The animal experiment has been approved by the Experimental Animal Ethics Committee of Tianjin University of Traditional Chinese Medicine (No. TCM-LAEC2023187g1549).

Objective To explore the protective mechanism of icariin on neuronal oxidative damage,providing a basic pharmacological basis for the treatment of cognitive impairment.Methods Glutamate was used to induce oxidative stress injury in HT22 cells.HT22 cells were divided into control group(normal cultured cells),model group(glutamate injury model)and experimental-L,-M,-H groups(5,10 and 20 μmol·L-1 icariin pretreatment for modeling,respectively).Cell proliferation was detected by cell counting kit-8(CCK-8)method;cytotoxicity was detected by lactate dehydrogenase(LDH)method;reactive oxygen species(ROS)levels were detected by flow cytometry;superoxide dismutase(SOD)levels were detected by biochemical kits;the expression levels of Kelch-like epichlorohydrin-related protein-1(Keap1),nuclear factor E2-related factor 2(Nrf2)were detected by Western blotting;the corresponding mRNA expression was detected by real-time fluorescence quantification polymerose chain reaction.Results The cell viability of control group,model group and experimental-L,-M,-H groups were(100.00±1.31)％,(66.38±2.44)％,(72.07±4.95)％,(82.41±3.57)％and(87.97±4.98)％;LDH release were(0.48±0.52)％,(18.82±2.09)％,(15.32±1.17)％,(10.37±1.39)％and(6.51±0.87)％;ROS level were(14.23±1.13)％,(41.74±1.60)％,(35.69±1.08)％,(33.28±1.69)％and(30.32±2.03)％;SOD levels were(54.84±1.17),(37.95±1.13),(48.02±1.28),(50.56±1.34)and(52.55±1.04)U·mg-1;Keap1 protein levels were 0.36±0.01,0.52±0.03,0.46±0.04,0.39±0.09 and 0.35±0.12;Nrf2 protein levels were 0.29±0.02,0.13±0.08,0.18±0.03,0.21±0.11 and 0.26±0.04;catalase(CAT)mRNA levels were 1.01±0.08,0.81±0.06,0.90±0.04,1.05±0.15 and 1.33±0.26;SOD mRNA levels were 1.09±0.12,0.83±0.03,0.86±0.08,0.94±0.08 and 1.09±0.16.Among the above indicators,the differences between the model group and the control group were statistically significant(all P＜0.01);the differences between the experimental-M,-H groups and the model group were statistically significant(P＜0.01,P＜0.05).Conclusion Icariin may activate the Keap1/Nrf2/antioxidant response element(ARE)signaling pathway,regulate the expression of related proteins,and reduce the level of ROS to effectively alleviate oxidative stress injury in neuronal cells.

Based on the views of FAN's Eight Dynamic-Static Sequential Methods,Professor FAN Guan-Jie believes that the obesity has the pathological factor of blood stasis in addition to qi deficiency and phlegm-damp.The compatibility of blood-activating and stasis-removing drugs for the treatment of obesity is accorded to the progression of the disease.In the clinic,Crataegi Fructus associated medicinal cluster of activating blood and removing stasis is usually recommended.The medicinal cluster is with Crataegi Fructus as the chief medicinal,and is compatible with drug pairs of Salviae Miltiorrhizae Radix et Rhizoma-Carthami Flos and Moutan Cortex-Paeoniae Radix Rubra.Crataegi Fructus associated medicinal cluster is able to treat qi and blood simultaneously,mainly aimed at removing blood stasis,supplemented by nourishing blood,promoting qi and blood movement,and invigorating spleen and stomach,which has the features of simultaneous dispersing and astringency,and proper combination of static therapy and dynamic therapy,and is suitable for obese patients with blood stasis obstruction in the vessels.