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.

Bufalin(BF)has a significant anti-tumor effect, but its clinical application is severely restricted by its high toxicity and poor water solubility. In this study, Scrophularia ningpoensis polysaccharide(SNP)and ursodeoxycholic acid(UDCA) were synthesized into an SNP-UDCA conjugate. BF was encapsulated to prepare BF/SNP-UDCA nanoparticles(NPs). The amphiphilic compound SNP-UDCA was synthesized via the one-step method, and its structure was characterized by Fourier-transform infrared spectroscopy(FT-IR)and proton nuclear magnetic resonance(~1H-NMR). The preparation process of BF/SNP-UDCA NPs was optimized through single-factor investigations. The encapsulation efficiency and drug-loading capacity of BF/SNP-UDCA NPs were determined by high-performance liquid chromatography(HPLC). The molecular form of BF/SNP-UDCA NPs was characterized by using a transmission electron microscope, X-ray diffraction(XRD), and differential scanning calorimeter(DSC). Additionally, the stability of BF/SNP-UDCA NPs was evaluated. The release behavior of BF/SNP-UDCA NPs at different pH values was determined by dialysis. The in vitro anti-tumor effect of BF/SNP-UDCA NPs was evaluated by MTT cytotoxicity assay, flow cytometry for apoptosis, and cellular uptake. The in vitro liver targeting was evaluated by measuring cellular uptake by laser confocal microscopy. The results demonstrated that the SNP-UDCA conjugate was successfully synthesized through an esterification reaction between SNP and UDCA. The preparation process of BF/SNP-UDCA NPs was as follows: the feed ratio of SNP-UDCA to BF was 2∶1, the ultrasonic time was 30 minutes, and the stirring time was two hours. The prepared BF/SNP-UDCA NPs were spherical in shape, with a particle size of(252.74±6.05)nm, an encapsulation efficiency of 65.00%±2.51%, and a drug-loading capacity of 6.80%±0.44%. The XRD and DSC results indicated that BF was encapsulated within the NPs and existed in a molecular or amorphous state. The short-term stability of BF/SNP-UDCA NPs and stability in DMEM medium are good, and their in vitro release behavior followed the first-order equation and was pH-dependent according to the in vitro experiment. Compared with BF, BF/SNP-UDCA NPs at the same concentration showed significantly stronger cytotoxicity and apoptotic effects on HepG2 cells(P<0.05, P<0.01). The uptake of coumarin 6(C6)/SNP-UDCA NPs in HepG2 cells was time-dependent and higher than that in HeLa cells at the same concentration of C6/SNP-UDCA NPs. Moreover, after treatment with SNP, the uptake of C6/SNP-UDCA NPs in HepG2 cells decreased. In conclusion, the preparation process of BF/SNP-UDCA NPs was simple and feasible. BF/SNP-UDCA NPs could enhance the targeting ability and inhibitory effect of BF on liver cancer cells. This study will provide a foundation for liver-targeting nanoformulations of BF.
Bufanolides/pharmacology* ; Nanoparticles/chemistry* ; Humans ; Drug Carriers/chemistry* ; Ursodeoxycholic Acid/chemistry* ; Antineoplastic Agents/pharmacology* ; Polysaccharides/chemistry* ; Scrophularia/chemistry* ; Liver Neoplasms/physiopathology* ; Hep G2 Cells

Objective Currently, there is no commercially available quantitative detection kit for the main Felis domestic allergen (Fel d 1) in China. To establish a rapid detection method for Fel d 1, this study aims to prepare monoclonal antibodies against Fel d 1 protein. Methods The codon preference of Escherichia coli was utilized to optimize and synthesize the Fel d 1 gene. The prokaryotic expression plasmid pET-28a-Fel d 1 was constructed and used to express and purify the recombinant Fel d 1 protein. Subsequently, the recombinant protein was immunized into BALB/c mice and monoclonal antibodies (mAbs) were prepared by the hybridoma technique. An indirect ELISA was established using the recombinant Fel d 1 as the coating antigen, and hybridoma cell lines were screened for positive clones. The specificity and antigenic epitopes of the mAbs were confirmed by Western blot analysis. Finally, the selected hybridoma cells were injected into the peritoneal cavities of BALB/c mice for large-scale monoclonal antibody production. Results The recombinant plasmid pET-28a-Fel d 1 was successfully constructed, and soluble Fel d 1 protein was obtained after optimizing the expression conditions. Western blot and antibody titer assays confirmed the successful isolation of two hybridoma cell lines, 7D11 and 5H4, which stably secreted mAbs specific to Fel d 1. Antibody characterization revealed that the 5H4 mAb was of the IgG2a subtype and could recognize the amino acid region 105-163 of Fel d 1, while the 7D11 mAb was the IgG1 subtype and could recognize the amino acid region 1-59. Conclusion The high-purity recombinant Fel d 1 protein produced in this study provides a promising alternative for clinical immunotherapy of cat allergies. Furthermore, the monoclonal antibody prepared in this experiment lays a material foundation for the in-depth study of the biological function of Fel d 1 and the development of ELISA detection.
Animals ; Antibodies, Monoclonal/biosynthesis* ; Mice, Inbred BALB C ; Cats ; Mice ; Allergens/genetics* ; Glycoproteins/genetics* ; Enzyme-Linked Immunosorbent Assay ; Hybridomas/immunology* ; Recombinant Proteins/genetics* ; Female ; Antibody Specificity

OBJECTIVES: To investigate the effects of quercetin on cuproptosis and L-type calcium currents in the myocardium of diabetic rats. METHODS: Forty SD rats were randomized into control group and diabetic model groups. The rat models of diabetes mellitus (DM) induced by high-fat and high-sugar diet combined with streptozotocin (STZ) injection were further divided into DM model group, quercetin treatment group, and empagliflozin treatment group (n=10). Blood glucose and body weight were measured every other week, and cardiac function of the rats was evaluated using echocardiography. HE staining, Sirius red staining, and wheat germ agglutinin (WGA) analysis were used to observe the changes in myocardial histomorphology, and serum copper levels and myocardial FDX1 expression were detected. In cultured rat cardiomyocyte H9c2 cells with high-glucose exposure, the effects of quercetin and elesclomol, alone or in combination, on intracellular CK-MB and LDH levels and FDX1 expression were assessed, and the changes in L-type calcium currents were analyzed using patch-clamp technique. RESULTS: The diabetic rats exhibited elevated blood glucose, reduced body weight, impaired left ventricular function, increased serum copper levels and myocardial FDX1 expression, decreased L-type calcium currents, and prolonged action potential duration. Quercetin and empagliflozin treatment significantly lowered blood glucose, improved body weight, and restored cardiac function of the diabetic rats, and compared with empagliflozin, quercetin more effectively reduced serum copper levels, downregulated FDX1 expression, and enhanced myocardial L-type calcium currents in diabetic rats. In H9c2 cells, high glucose exposure significantly increased myocardial expressions of FDX1, CK-MB and LDH, which were effectively lowered by quercetin treatment; Elesclomol further elevated FDX1, CK-MB and LDH levels in the exposed cells, and these changes were not significantly affected by the application of quercetin. CONCLUSIONS Quercetin ameliorates myocardial injury in diabetic rats possibly by suppressing myocardial cuproptosis signaling and restoring L-type calcium channel activity.
Animals ; Quercetin/pharmacology* ; Calcium Channels, L-Type/metabolism* ; Diabetes Mellitus, Experimental/metabolism* ; Rats, Sprague-Dawley ; Rats ; Myocytes, Cardiac/drug effects* ; Myocardium/pathology* ; Male

This study aimed to comprehensively examine the association of gallstones, cholecystectomy, and cancer risk. Multivariable logistic regressions were performed to estimate the observational associations of gallstones and cholecystectomy with cancer risk, using data from a nationwide cohort involving 239 799 participants. General and gender-specific two-sample Mendelian randomization (MR) analysis was further conducted to assess the causalities of the observed associations. Observationally, a history of gallstones without cholecystectomy was associated with a high risk of stomach cancer (adjusted odds ratio (aOR)=2.54, 95% confidence interval (CI) 1.50-4.28), liver and bile duct cancer (aOR=2.46, 95% CI 1.17-5.16), kidney cancer (aOR=2.04, 95% CI 1.05-3.94), and bladder cancer (aOR=2.23, 95% CI 1.01-5.13) in the general population, as well as cervical cancer (aOR=1.69, 95% CI 1.12-2.56) in women. Moreover, cholecystectomy was associated with high odds of stomach cancer (aOR=2.41, 95% CI 1.29-4.49), colorectal cancer (aOR=1.83, 95% CI 1.18-2.85), and cancer of liver and bile duct (aOR=2.58, 95% CI 1.11-6.02). MR analysis only supported the causal effect of gallstones on stomach, liver and bile duct, kidney, and bladder cancer. This study added evidence to the causal effect of gallstones on stomach, liver and bile duct, kidney, and bladder cancer, highlighting the importance of cancer screening in individuals with gallstones.
Humans ; Mendelian Randomization Analysis ; Gallstones/complications* ; Female ; Male ; Cholecystectomy/statistics & numerical data* ; Middle Aged ; Risk Factors ; Aged ; Adult ; Neoplasms/etiology* ; Stomach Neoplasms/epidemiology*

OBJECTIVE: To investigate the predictive value of oxygenation index (PaO₂/FiO₂) at intensive care unit (ICU) admission on 30-day mortality in patients with sepsis. METHODS: A retrospective study was conducted. Patients with sepsis who were hospitalized in the ICU of the Affiliated Hospital of Jining Medical University from April 2015 to October 2023 were enrolled. The demographic information, comorbidities, sites of infection, vital signs and laboratory test indicators at the time of admission to the ICU, disease severity scores within 24 hours of admission to the ICU, treatment process and prognostic indicators were collected. According to the PaO₂/FiO₂ at ICU admission, patients were divided into Q1 group (PaO₂/FiO₂ of 4.1-16.4 cmHg, 1 cmHg ≈ 1.33 kPa), Q2 group (PaO₂/FiO₂ of 16.5-22.6 cmHg), Q3 group (PaO₂/FiO₂ of 22.7-32.9 cmHg), and Q4 group (PaO₂/FiO₂ of 33.0-94.8 cmHg). Differences in the indicators across the four groups were compared. Multifactorial Cox regression analysis was used to assess the relationship between PaO₂/FiO₂ and 30-day mortality of patients with sepsis. The predictive value of PaO₂/FiO₂, sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation II (APACHE II) on 30-day prognosis of patients with sepsis was analyzed by receiver operator characteristic curve (ROC curve). RESULTS: A total of 1 711 patients with sepsis were enrolled, including 428 patients in Q1 group, 424 patients in Q2 group, 425 patients in Q3 group, and 434 patients in Q4 group. 622 patients died at 30-day, the overall 30-day mortality was 36.35%. There were statistically significant differences in age, body mass index (BMI), history of smoking, history of alcohol consumption, admission heart rate, respiratory rate, APACHE II score, SOFA score, Glasgow coma score (GCS), site of infection, Combined chronic obstructive pulmonary disease (COPD), blood lactic acid (Lac), prothrombin time (PT), albumin (Alb), total bilirubin (TBil), pH, proportion of mechanical ventilation, duration of mechanical ventilation, proportion of vasoactive medication used, and maximal concentration, length of ICU stay, hospital stay, incidence of acute kidney injury, in-hospital mortality, 30-day mortality among the four groups. Multivariate Cox regression analysis showed that after adjusting for confounding factors, for every 1 cmHg increase in PaO₂/FiO₂ at ICU admission, the 30-day mortality risk decreased by 2% [hazard ratio (HR) = 0.98, 95% confidence interval (95%CI) was 0.98-0.99, P < 0.001]. The 30-day mortality risk in the Q4 group was reduced compared with the Q1 group by 41% (HR = 0.59, 95%CI was 0.46-0.76, P < 0.001). The fitted curve showed that a curvilinear relationship between PaO₂/FiO₂ and 30-day mortality after adjustment for confounders. In the inflection point analysis, for every 1 cmHg increase in PaO₂/FiO₂ at PaO₂/FiO₂ < 28.55 cmHg, the risk of 30-day death in sepsis patients was reduced by 5% (HR = 0.95, 95%CI was 0.94-0.97, P < 0.001); when PaO₂/FiO₂ ≥ 28.55 cmHg, there was no statistically significant association between PaO2/FiO2 and the increase in the risk of 30-day death in sepsis (HR = 1.01, 95%CI was 0.99-1.02, P = 0.512). ROC curve analysis showed that the area under the curve (AUC) for the prediction of 30-day mortality by admission PaO₂/FiO₂ in ICU sepsis patients was 0.650, which was lower than the predictive ability of the SOFA score (AUC = 0.698) and APACHE II score (AUC = 0.723). CONCLUSION In patients with sepsis, PaO₂/FiO₂ at ICU admission is strongly associated with 30-day mortality risk, alerting healthcare professionals to pay attention to patients with low PaO₂/FiO₂ for timely interventions.
Humans ; Sepsis/mortality* ; Intensive Care Units ; Retrospective Studies ; Prognosis ; Hospital Mortality ; Oxygen ; Male ; Predictive Value of Tests ; Female ; Middle Aged ; Aged

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Background/Aims: Low educational attainment is a well-established risk factor for nonalcoholic fatty liver disease (NAFLD) in developed areas. However, the association between educational attainment and the risk of NAFLD is less clear in China. Methods: A cross-sectional study including over 200,000 Chinese adults across mainland China was conducted. Information on education level and lifestyle factors were obtained through standard questionnaires, while NAFLD and advanced fibrosis were diagnosed using validated formulas. Outcomes included the risk of NAFLD in the general population and high probability of fibrosis among patients with NAFLD. Logistic regression analysis was employed to estimate the risk of NAFLD and fibrosis across education levels. A causal mediation model was used to explore the potential mediators. Results: Comparing with those receiving primary school education, the multi-adjusted odds ratios (95% confidence intervals) for NAFLD were 1.28 (1.16 to 1.41) for men and 0.94 (0.89 to 0.99) for women with college education after accounting for body mass index. When considering waist circumference, the odds ratios (95% CIs) were 0.94 (0.86 to 1.04) for men and 0.88 (0.80 to 0.97) for women, respectively. The proportions mediated by general and central obesity were 51.00% and 68.04% for men, while for women the proportions were 48.58% and 32.58%, respectively. Furthermore, NAFLD patients with lower educational attainment showed an incremental increased risk of advanced fibrosis in both genders. Conclusions In China, a low education level was associated with a higher risk of prevalent NAFLD in women, as well as high probability of fibrosis in both genders.