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.

BACKGROUND:Ferroptosis is a mode of programmed cell death distinct from apoptosis,necrosis,and other novel cellular deaths,which occurs mainly due to accumulated lipid peroxidation.Ferroptosis has been shown to be involved in the pathological process following subarachnoid hemorrhage.Baicalein,serving as an adept sequestered of iron,evinces its prowess by quelling lipid peroxidative cascades.Nonetheless,the enigma lingers as to whether baicalein possesses the capacity to ameliorate neuronal ferroptosis,elicited in the wake of early brain injury after subarachnoid hemorrhage. OBJECTIVE:To investigate the effect and mechanism of baicalein on neuronal ferroptosis after subarachnoid hemorrhage. METHODS:Primary neuronal cells were extracted from C57BL/6L fetal mice at 16-17 days of gestation.Hemoglobin was used to stimulate primary neuronal cells to simulate an in vitro subarachnoid hemorrhage model.The viability of primary neuronal cells treated with baicalein at concentrations of 5,15,25,50,and 100 μmol/L for 24 hours was detected by CCK-8 assay to determine the optimal concentration of baicalein.Primary neuronal cells were divided into control group,hemoglobin group,and hemoglobin+baicalein group.The levels of reactive oxygen species and malondialdehyde in cells were detected by kits.The mRNA expressions of ferroptosis-related markers PTGS2,SLC7A11,and glutathione peroxidase 4 were detected by RT-PCR.The primary neuronal cells were further divided into control group,SLC7A11 inhibitor Erastin group,hemoglobin group,hemoglobin+baicalein group,and hemoglobin+baicalein+Erastin group.The expression of the ferroptosis related markers SLC7A11 and glutathione peroxidase 4 was detected by western blot assay. RESULTS AND CONCLUSION:(1)Baicalein(25 μmol/L)was selected as the following experimental concentration.(2)Compared with the hemoglobin group,the level of malondialdehyde and the level of reactive oxygen species were significantly decreased(P<0.05)in the hemoglobin+baicalein group.(3)Compared with the hemoglobin group,the mRNA expression of PTGS2 significantly decreased,and the mRNA expression of SLC7A11 and glutathione peroxidase 4 significantly increased(P<0.000 1)in the hemoglobin+baicalein group.(4)SLC7A11 inhibitor Erastin could reverse the baicalin-improved ferroptosis effect to a certain extent(P<0.05).(5)The results showed that baicalein could alleviate the ferroptosis of neuronal cells after subarachnoid hemorrhage through the SLC7A11/GPX4 pathway.

Objective To determine the acetylation level of nucleophosmin(NPM)in female breast cancer and to discuss its function through mutation of modified lysine sites.To construct positive and negative NPM mutants on its acetylated lysine sites and to express them in breast cancer cells.Methods Acetylation level and acetylated lysine sites of NPM in three breast cancer tissues and para-carcinoma tissues were detected by acetylome technology;NPM mutants were constructed by site-directed mutagenesis PCR,specific PCR products were digested by DpnI and transformed into Escherichia coli(E.coli)to obtain specific plasmids for mutants;The accuracy of mutants were verified by double restriction enzyme digestion and sequencing;The mutants were expressed in BT-549 cells by transient transfection and verified by RT-PCR method.Protein expression and acetylation level of NPM were validated by Western blotting;Function of NPM acetylation was analyzed by proteomic detection and bioinformatic analysis.Results The 27th and 32nd lysine of NPM were highly acetylated in breast cancer tissues,which were 2.76 and 2.22 times higher than those in adjacent normal tissues,respectively;The NPM mutants showed the same molecular weight as that of wild type NPM and contained expected mutation sites;Corresponding NPM mRNA levels of BT-549 cells transfected with NPM mutants were significantly increased.With the increase of wild type NPM expression level,NPM acetylation level increased,while decreased after 27th lysine underwent negative mutation.NPM acetylation can significantly change the expression levels of 101 proteins in BT-549 cells,which are enriched in regulation of cellular macromolecule biosynthesis,DNA-template transcription,RNA biosynthesis and RNA metabolism process.Conclusion NPM is highly acetylated in breast cancer and can play a key role in cellular macromolecule biosynthesis,DNA-templated transcription,RNA biosynthesis and RNA metabolism process.

Objective This study aimed to investigate the effect of stage Ⅰ comprehensive cardiac rehabili-tation in patients with acute ST elevation myocardial infarction(STEMI)after emergency percutaneous coronary intervention(PCI).Methods A total of 72 patients with acute ST-segment elevation myocardial infarction combined with PCI admitted to the Department of Cardiovascular Medicine of Beijing Electric Power Hospital of State Grid Corporation from June 2021 to June 2022,which were selected as the research objectsand divided into control group and observation group randomly(36 cases in each group).The control group was treated with routine nursing and health education,and the observation group with stage Ⅰ comprehensive cardiac rehabilitation,including initial assessment(cardiovascular comprehensive assessment),exercise training(exercise training and breathing train-ing),daily activity suggestions and health education,discharge assessment(six-minute walking test and Barthel index assessment).The score of Barthel index(BI)at discharge,the 6-minute walking test distance(6MWD)at discharge,the incidence of major adverse cardiovascular event(MACE)during hospitalization and within one month of discharge,and the length of stay were compared between the two groups.Results After intervention,the six-minute walking test distance(6MWD)and Barthel index(BI)score in the observation group were better than those in the control group,the difference was statistically significant(P<0.05).The incidence of major adverse cardiovascular events(MACE)during hospitalization and one month after discharge was lower in the observation group than in the control group,and the difference was statistically significant(P<0.05).The length of hospital-ization in observation group was lower than that in control groupbut there was no statistical difference(P>0.05).Conclusion The application of phase Ⅰ comprehensive cardiac rehabilitation training in patients with acute ST-segment elevation myocardial infarction combined with emergency PCI could improve the patients'exercise ability,improve their ability of daily activity,reduce the incidence of major adverse cardiovascular events(MACE)in the early stage of the disease,facilitate the patients to return to their families and society as soon as possible,and improve their quality of life.It has high clinical application value.

Objective To observe the effectiveness of fluorescence labeling-based assay bundle intervention in the prevention and control of multidrug-resistant organism(MDRO)infection.Methods Patients who were detected MDRO in a hospital from January to December 2022 were selected as the research subjects.MDRO monitoring data and implementation status of prevention and control measures were collected.Fluorescence labeling assay was adopted to monitor the cleaning and disinfection effectiveness of the surrounding object surface of the bed units.Based on the bundled prevention and control measures as well as management mode of the pre-intervention group,the post-intervention group implemented enhanced rectification measures for the problems found by the pre-interven-tion group.Changes in relevant indicators between January-June 2022(before intervention)and July-December 2022(after intervention)were compared.Results There were 136 MDRO-infected patients in the pre-intervention group,208 MDRO strains were detected and 10 healthcare-associated infection(HAI)occurred.There were 128 MDRO-infected patients in the post-intervention group,198 MDRO strains were detected and 9 HAI occurred.Af-ter intervention,the total detection rates of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-re-sistant Acinetobacter baumannii(CRAB),and total MDRO from patients decreased significantly compared to before intervention(all P＜0.05).After intervention,the detection rates of MRSA,carbapenem-resistant Pseudomonas aeruginosa(CRPA),CRAB,and total MDRO from the surrounding object surface were all lower than those before intervention(all P＜0.05).The detection rate of MDRO from surrounding object surface before intervention was 34.52％,which showed a decreased trend after intervention(P＜0.05).The clearance rate of fluorescent labeled markers before intervention was 41.84％,which showed an upward trend after implementing intervention measures(from July to December),and increased to 85.00％at the end of intervention(November-December).The comp-liance rates of issuing isolation medical orders,placing isolation labels,using medical supplies exclusively,and cor-rectly handling medical waste after intervention have all increased compared to before intervention(all P＜0.05).Conclusion Adopting fluorescence labeling-based assay bundle intervention can effectively improve the effectiveness of MDRO infection prevention and control.

"MS/MS spectrum to structure"plays a critical role in the confirmative identification of complicated matrices and is currently regarded as an extremely challenging endeavor.MS/MS information provides vital clues to structural identification.In this study,a strategy was proposed to facilitate unambiguous identification through matching MS3 with MS2 spectra.Initially,MS3 spectra of the featured ions(c-and y-type ions)generated by the decomposition of ester functional group in esters and the MS2 spectrum of the structural unit([M-H]-)were all captured on the Qtrap-MS platform equipped with two tandem-in-space collision cells,including the second quadrupole cell(q2)and linear ion trap(LIT)chambers(actually the third quadrupole unit).Subsequently,the MS/MS spectrum matching between MS3 spectra of the ester compound and MS2 spectra of the structural unit(s)were achieved.As a result,the findings corresponding to MS3 and MS2 spectra matching were summarized.Finally,based on HR-MS/MS information of total salvianolic acid derivatives(TSA),36 kinds of compounds were preliminarily identified through matching with literature information and database retrieval.The applicability of MS3 and MS2 spectra matching strategy was further justified by the confirmative identification of phenolic acid compounds(Rosmarinic acid and salvianolic acid B)in TSA.Above all,MS3 and MS2 spectra matching strategy was quite meaningful towards advancing"MS/MS spectrum to structure"analysis through recognizing and identifying featured fragment ions,and also provided inspiration and new insights for the structural characterization.

BACKGROUND:The pituitary gland is an important endocrine organ in the body.Certain diseases can cause damage to the pituitary gland,such as pituitary adenoma and abnormal hormone secretion.Pituitary stem cells,due to their self-renewal and multi-directional differentiation potential,are expected to become a new therapeutic approach for repairing damaged pituitary glands. OBJECTIVE:To isolate and culture pituitary stem cells using the suspension cell ball culture method and identify their proliferation and differentiation ability. METHODS:Pituitary stem cells were isolated and cultured from the pituitary gland of newborn New Zealand white rabbits using the suspension cell ball culture method,and their morphological characteristics were observed.Immunofluorescence cytochemistry was used to detect the expression of pituitary stem cell markers SOX2 and Nestin.EdU labeling method was utilized to detect the proliferative ability of pituitary stem cells.After adherent and induced differentiation,the hormone levels in the culture medium were detected by ELISA. RESULTS AND CONCLUSION:Pituitary stem cell spheres could be successfully isolated by the suspension cell ball culture method,with strong proliferative ability.Positive expression of stem cell-specific markers SOX2 and Nestin was found in the cultured cells.After induction and differentiation,adrenocorticotropic hormone,thyroid hormone,growth hormone,luteinizing hormone,follicle-stimulating hormone,and prolactin levels significantly increased in the medium(P<0.001),with strong differentiation ability.

ObjectiveDetection and quantification of RNA synthesis in cells is a widely used technique for monitoring cell viability, health, and metabolic rate.After exposure to environmental stimuli, both the internal reference gene and target gene would be degraded. As a result, it is imperative to consider the accurate capture of nascent RNA and the detection of transcriptional levels of RNA following environmental stimulation. This study aims to create a Click Chemistry method that utilizes its property to capture nascent RNA from total RNA that was stimulated by the environment. MethodsThe new RNA was labeled with 5-ethyluridine (5-EU) instead of uracil, and the azido-biotin medium ligand was connected to the magnetic sphere using a combination of “Click Chemistry” and magnetic bead screening. Then the new RNA was captured and the transcription rate of 16S rRNA was detected by fluorescence molecular beacon (M.B.) and quantitative reverse transcription PCR (qRT-PCR). ResultsThe bacterial nascent RNA captured by “Click Chemistry” screening can be used as a reverse transcription template to form cDNA. Combined with the fluorescent molecular beacon M.B.1, the synthesis rate of rRNA at 37℃ is 1.2 times higher than that at 15℃. The 16S rRNA gene and cspI gene can be detected by fluorescent quantitative PCR,it was found that the measured relative gene expression changes were significantly enhanced at 25℃ and 16℃ when analyzed with nascent RNA rather than total RNA, enabling accurate detection of RNA transcription rates. ConclusionCompared to other article reported experimental methods that utilize screening magnetic columns, the technical scheme employed in this study is more suitable for bacteria, and the operation steps are simple and easy to implement, making it an effective RNA capture method for researchers.

ObjectiveSodium hyaluronate (HA) was used as the research object to modify it with phenolic acid in order to obtain the molecular structure with better antioxidant activity or even new activity. MethodsIn this study, 5 kinds of phenolic acid-sodium hyaluronate was prepared by free radical-mediated grafting method, and the grafts with the highest grafting degree were selected to optimize the synthesis conditions. Then, grafts structure and physicochemical properties were analyzed. The grafts were characterized by IR, UV, ¹H NMR, FESEM and TGA spectra. The in vitro antioxidant capacity of grafts was determined by the scavenging ability of DPPH·, ABTS⁺· and O^2-·. ResultsAmong 5 kinds of phenolic acid-sodium hyaluronate, the grafting rate of ferulic acid-sodium hyaluronate copolymer (FA-HA) was highest , which was chosen as experimental sample in the following tests. Firstly, the reaction conditions were investigated and the highest grafting rate was (16.59±0.31) mg/g at the optimal preparation conditions. Then, FA-HA structure and physicochemical properties were analyzed. Data from UV, IR, ¹H NMR analyses, TGA showed that FA were successfully grafted to HA. Compared with HA, the results of gel permeation chrematography (GPC) showed that the molecular mass distribution ofFA-HA copolymer decreased from 34.4 to 31.5 ku, but the uniformity of molecular distribution was improved. FESEM results showed that the structure of copolymer exhibited a closely connected lamellar structure with a relatively smooth surface. TGA results showed that thermal stability of FA-HA had a little decline. The antioxidant performance in vitro results showed that, during 0.25-10 g/L, FA-HA can eliminate (83.76±4.86)% DPPH·, (76.95±5.06)% ABTS⁺· and (83.08±2.51)% O^2-· respectively at 10 g/L. which were higher than that of native HA and FA. ConclusionFA and HA were successfully grafted together by free radical grafting, and the grafted FA-HA had better antioxidant activity in vitro, which provided a theoretical basis for further research and development of phenolic acid-HA grafts.

In order to study the compounds from Glechoma longituba (Nakai) Kupr. and explore the substance bases of its dissipating blood stasis, MCI, silica gel, Sephadex LH-20, ODS column chromatography and preparative thin layer chromatography were used to isolate and purify the compounds. The structures were identified by MS, 1D NMR, and 2D NMR spectra analysis, etc. Eight triterpenoids were isolated from dichloromethane fraction of ethanol extract from G. longituba and identified as 2α,3α,16β-trihydroxy-13α,27-cyclours-11-en-28-oic acid (1), 28-norurs-12-ene-3β,17β-diol (2), 28-norolean-12-ene-3β,17β-diol (3), oleanonic acid (4), 3β,13β-dihydroxyurs-11-en-28-oic acid (5), uvaol (6), oleanolic acid (7), ursolic acid (8). Compound 1 is a new hexacyclic triterpene with 13α,27-cyclopropane structure, named euscaphic acid H; compounds 2 and 3 were isolated from Lamiaceae for the first time while compounds 4 and 5 were isolated from this genus. The in vitro anticoagulant activity of triterpenoids was evaluated by four coagulation indexes (activated partial thromboplastin time, APTT; thrombin time, TT; prothrombin time, PT; fibrinogen, FIB). Among them, compounds 1 and 6 showed obvious anticoagulant effects.