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 the construction of α-1,3-galactosyltransferase (GGTA1) gene-knockout (GTKO) Diannan miniature pigs and the kidney xenotransplantation from pigs to rhesus macaques, and to assess the effectiveness of GTKO pigs. Methods The GTKO Diannan miniature pigs were constructed using the CRISPR/Cas9 gene-editing system and somatic cell cloning technology. The phenotype of GTKO pigs was verified through polymerase chain reaction, Sanger sequencing and immunofluorescence staining. Flow cytometry was used to detect antigen-antibody (IgM) binding and complement-dependent cytotoxicity. Kidney xenotransplantation was performed from GTKO pigs to rhesus macaques. The humoral immunity, cellular immunity, coagulation and physiological indicators of the recipient monkeys were monitored. The function and pathological changes of the transplanted kidneys were analyzed using ultrasonography, hematoxylin-eosin staining, immunohistochemical staining and immunofluorescence staining. Results Single-guide RNA (sgRNA) targeting exon 4 of the GGTA1 gene in Diannan miniature pigs was designed. The pGL3-GGTA1-sgRNA1-GFP vector was transfected into fetal fibroblasts of Diannan miniature pigs. After puromycin selection, two cell clones, C59# and C89#, were identified as GGTA1 gene-knockout clones. These clones were expanded to form cell lines, which were used as donor cells for somatic cell nuclear transfer. The reconstructed embryos were transferred into the oviducts of trihybrid surrogate sows, resulting in 13 fetal pigs. Among them, fetuses F04 and F11 exhibited biallelic mutations in the GGTA1 gene, and F04 had a normal karyotype. Using this GTKO fetal pig for recloning and transferring the reconstructed embryos into the oviducts of trihybrid surrogate sows, seven surviving piglets were obtained, all of which did not express α-Gal epitope. The binding of IgM from the serum of rhesus monkey 20# to GTKO pig PBMC was reduced, and the survival rate of GTKO pig PBMC in the complement-dependent cytotoxicity assay was higher than that of wild-type pig. GTKO pig kidneys were harvested and perfused until completely white. After the left kidney of the recipient monkey was removed, the pig kidney was heterotopically transplanted. Following vascular anastomosis and blood flow restoration, the pig kidney rapidly turned pink without hyperacute rejection (HAR). Urine appeared in the ureter 6 minutes later, indicating successful kidney transplantation. The right kidney of the recipient was then removed. Seven days after transplantation, the transplanted kidney had good blood flow, the recipient monkey's serum creatinine level was stable, and serum potassium and cystatin C levels were effectively controlled, although they increased 10 days after transplantation. Seven days after transplantation, the levels of white blood cells, lymphocytes, monocytes and eosinophils in the recipient monkey increased, while platelet count and fibrinogen levels decreased. The activated partial thromboplastin time, thrombin time and prothrombin time remained relatively stable but later showed an upward trend. The recipient monkey survived for 10 days. At autopsy, the transplanted kidney was found to be congested, swollen and necrotic, with a small amount of IgG deposition in the renal tissue, and a large amount of IgM, complement C3c and C4d deposition, as well as CD68⁺ macrophage infiltration. Conclusions The kidneys of GTKO Diannan miniature pigs may maintain normal renal function for a certain period in rhesus macaques and effectively overcome HAR, confirming the effectiveness of GTKO pigs for xenotransplantation.

【Objective】 To investigate the association between genetic variations in the glucagon-like peptide-1 receptor (GLP-1R) gene and BP responses to sodium and potassium intake. 【Methods】 A total of 514 subjects from 124 families were recruited in Meixian County, Shaanxi Province, in 2004, resulting in the establishment of a "salt-sensitive hypertension study cohort" . The subjects followed a dietary regimen which involved a normal diet for 3 days, a low-salt diet for 7 days, a high-salt diet for 7 days, and a high-salt potassium-supplemented diet for 7 days. BP measurement was conducted at different intervention periods, and peripheral blood samples were collected. Additionally, eight single nucleotide polymorphisms (SNPs) of the GLP-1R gene were genotyped using the MassARRAY detection platform. 【Results】 The GLP-1R gene SNP rs9462472 exhibited a significant association with systolic BP, diastolic BP, and mean arterial pressure response to high-salt intervention. Similarly, SNP rs2268637 showed a significant association with systolic BP response to high-salt intervention. Furthermore, SNP rs2268637 was significantly associated with systolic BP and mean arterial pressure responses to high-salt plus potassium supplementation intervention. 【Conclusion】 Our findings indicate a significant association of genetic variations in the GLP-1R gene with BP responses to sodium and potassium intake. This suggests that the GLP-1R gene plays a role in the regulation of BP salt sensitivity and potassium sensitivity.

Surgical operation is the main treatment of oral and maxillofacial tumors.Dysphagia is a common postoperative complication.Swal-lowing disorder can not only lead to mis-aspiration,malnutrition,aspiration pneumonia and other serious consequences,but also may cause psychological problems and social communication barriers,affecting the quality of life of the patients.At present,there is no systematic evalua-tion and rehabilitation management plan for the problem of swallowing disorder after oral and maxillofacial tumor surgery in China.Combining the characteristics of postoperative swallowing disorder in patients with oral and maxillofacial tumors,summarizing the clinical experience of ex-perts in the field of tumor and rehabilitation,reviewing and summarizing relevant literature at home and abroad,and through joint discussion and modification,a group of national experts reached this consensus including the core contents of the screening of swallowing disorders,the phased assessment of prognosis and complications,and the implementation plan of comprehensive management such as nutrition management,respiratory management,swallowing function recovery,psychology and nursing during rehabilitation treatment,in order to improve the evalua-tion and rehabilitation of swallowing disorder after oral and maxillofacial tumor surgery in clinic.

The detection principle of microfluidic microfluidic technology was introduced.The current research status of microfluidic platform-based SARS-CoV-2 nucleic acid detection technologies were reviewed such as reverse transcription quantitative real-time polymerase chain reaction(RT-qPCR),digital PCR,isothermal amplification and clustered regularly interspaced palindromic repeats/CRISPR-associated protein.The deficiencies of microfluidic platform-based SARS-CoV-2 nucleic acid detection were analyzed.It's pointed out microfluidic platform-based SARS-CoV-2 nucleic acid detection had to be optimized and validated clinically in specialty,sensitivity,detection limit,reproducibility,informatization,quality control and reagent cost.[Chinese Medical Equipment Journal,2024,45(1):101-107]

Intermittent theta burst stimulation (iTBS), a time-saving and cost-effective repetitive transcranial magnetic stimulation regime, has been shown to improve cognition in patients with Alzheimer's disease (AD). However, the specific mechanism underlying iTBS-induced cognitive enhancement remains unknown. Previous studies suggested that mitochondrial functions are modulated by magnetic stimulation. Here, we showed that iTBS upregulates the expression of iron-sulfur cluster assembly 1 (ISCA1, an essential regulatory factor for mitochondrial respiration) in the brain of APP/PS1 mice. In vivo and in vitro studies revealed that iTBS modulates mitochondrial iron-sulfur cluster assembly to facilitate mitochondrial respiration and function, which is required for ISCA1. Moreover, iTBS rescues cognitive decline and attenuates AD-type pathologies in APP/PS1 mice. The present study uncovers a novel mechanism by which iTBS modulates mitochondrial respiration and function via ISCA1-mediated iron-sulfur cluster assembly to alleviate cognitive impairments and pathologies in AD. We provide the mechanistic target of iTBS that warrants its therapeutic potential for AD patients.
Humans ; Mice ; Animals ; Transcranial Magnetic Stimulation ; Alzheimer Disease/therapy* ; Cognitive Dysfunction/therapy* ; Cognition ; Sulfur ; Iron ; Iron-Sulfur Proteins ; Mitochondrial Proteins

Background::Pancreatic ductal adenocarcinoma (PDAC) is one of the main types of malignant tumor of the digestive system, and patient prognosis is affected by difficulties in early diagnosis, poor treatment response, and a high postoperative recurrence rate. Carbohydrate antigen 19-9 (CA19-9) has been widely used as a biomarker for the diagnosis and postoperative follow-up of PDAC patients. Nevertheless, the production mechanism and potential role of CA19-9 in PDAC progression have not yet been elucidated.Methods::We performed single-cell RNA sequencing on six samples pathologically diagnosed as PDAC (three CA19-9-positive and three CA19-9-negative PDAC samples) and two paracarcinoma samples. We also downloaded and integrated PDAC samples (each from three CA19-9-positive and CA19-9-negative patients) from an online database. The dynamics of the proportion and potential function of each cell type were verified through immunofluorescence. Moreover, we built an in vitro coculture cellular model to confirm the potential function of CA19-9. Results::Three subtypes of cancer cells with a high ability to produce CA19-9 were identified by the markers TOP2A, AQP5, and MUC5AC. CA19-9 production bypass was discovered on antigen-presenting cancer-associated fibroblasts (apCAFs). Importantly, the proportion of immature ficolin-1 positive (FCN1+) macrophages was high in the CA19-9-negative group, and the proportion of mature M2-like macrophages was high in the CA19-9-positive group. High proportions of these two macrophage subtypes were associated with an unfavourable clinical prognosis. Further experiments indicated that CA19-9 could facilitate the transformation of M0 macrophages into M2 macrophages in the tumor microenvironment. Conclusions::Our study described CA19-9 production at single-cell resolution and the dynamics of the immune atlas in CA19-9-positive and CA19-9-negative PDAC. CA19-9 could promote M2 polarization of macrophage in the pancreatic tumor microenvironment.

The main chemical components of Allii Macrostemonis Bulbus and components in serum were analyzed and identified rapidly and precisely by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS)technique in this study.The compounds were identified based on the relative molecular mass,fragmentation ions,and retention time of chromatographic peaks.A total of 36 kinds of chemical components were identified from Allii Macrostemonis Bulbus,including 28 kinds of saponins,3 kinds of amino acids,2 kinds of flavonoids,one kind of organosulfur compound,one kind of nucleoside,and one kind of hormone-lipid compound.In addition,8 kinds of compounds of Allii Macrostemonis Bulbus were identified from the serum.Based on the intersection compounds of which detected in serum and screened out by TCMSP platform database,by using targeted network pharmacology and molecular docking technology,a"drug-component-target-pathway"association network was constructed.Naringenin,quercetin,macrostemonoside E and 25(R)-26-O-β-D-glucopyranosyl-22-hydroxy-5β-furostan-3-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranoside were screened as the main active constituents of Allii Macrostemonis Bulbus in the treatment of hyperlipidemia.In addition,adenosine 5′-monophosphate-activated protein kinase(AMPK),tumor necrosis factor(TNF),vascular endothelial growth factor A(VEGFA)and matrix metallopeptidase 9(MMP9)were the key action targets for Allii Macrostemonis Bulbus in the treatment of hyperlipidemia.Molecular docking was performed using the main pharmacodynamic components and key action targets.The results indicated that all the four active components showed strongly bound to AMPK.This suggested that the regulation of lipid metabolism might be the key mechanism of Allii Macrostemonis Bulbus in antihyperlipidemic effect.This study provided a data reference for the research on the pharmacodynamic components of Allii Macrostemonis Bulbus,and provided a basis for the improvement of quality standard of Allii Macrostemonis Bulbus.

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:The classification model of prognosis of elderly cancer patients in rural areas of Shaanxi province was constructed based on machine learning algorithm, and its effectiveness was verified, providing reference for early prognosis recognition and intervention treatment.Methods:Using a multicenter, cross-sectional survey method and convenience sampling method, 597 elderly cancer patients in rural areas hospitalized in 9 different medical institutions (Shaanxi Cancer Hospital and its member units of specialty alliance) in Shaanxi Province from July to August 2022 were selected as the research objects, and a variable database of "basic information", "self-care ability", "symptoms", "comprehensive needs" and "quality of life" of elderly cancer patients in rural areas was established. Machine learning and statistical analysis were carried out to explore the important prognostic characteristics of elderly cancer patients in rural areas, and a prognostic classification model for elderly cancer patients in rural areas was constructed and verified.Results:The 597 valid questionnaires were ultimately collected.Among the 597 elderly cancer patients in rural areas, 207 were males and 390 were females, aged (69.56 ± 8.84) years. The results of cluster exploration showed that the prognosis of elderly cancer patients in rural areas was divided into three categories: good, medium and poor. The areas under the working characteristic curves of the subjects in good, medium and poor were 0.84, 0.79 and 0.69, respectively. The results of characteristic exploration showed that 10 indicators of "whether accompanied by metastasis", "distress", "sadness", "numbness", "eating", "walking", "fatigue", "forgetfulness", "fun of life" and "relationship with others" were important characteristic indicators of prognosis evaluation of elderly cancer patients in rural areas. There were statistically significant differences among the 10 important characteristic indicators in the three categories of prognosis of rural elderly cancer patients ( χ2=21.07, H values were 18.51-144.38, all P<0.01). There were statistically significant differences in the three categories of "comprehensive needs", "quality of life", "self-care ability" and "symptoms" ( H values were 519.40, 40.80, 103.69, all P<0.01). Conclusions:The construction and verification of a prognostic classification model for elderly cancer patients in rural areas based on machine learning algorithm can effectively explore the important characteristic indicators and prognostic classification of elderly cancer patients in rural areas, and provide basis and guidance for clinical medical staff to make individualized plans.