A prokaryotic expression vector for the mutant diphtheria toxin CRM197 was constructed and expressed in Esch-erichia coli cells.Anti-CRM197 antibody concentrations were detected in serum samples of healthy volunteers.The crm 197 gene was codon-optimized in E.coli and cloned into the plasmid pET28a(+)under optimized expression conditions.CRM197 was purified using Ni-NTA spin columns and ion exchange chromatography,and confirmed by western blot analysis.The puri-fied CRM197 was used to detect specific anti-CRM197 antibody levels in serum samples of different age groups.The results showed that soluble codon-optimized CRM197 was successfully expressed under optimized expression conditions.The purity of CRM197 was more than 95％,as determined with Ni-NTA spin columns and ion exchange chromatography,consistent with the single specific bands obtained by western blot analysis and detection of serum levels of the anti-CRM197 antibody.Collec-tively,these results confirmed that the proposed expression strategy achieved high-yield production of soluble CRM197,al-though high levels in human serum may affect evaluation of immune interactions with glycan-CRM197 conjugates for applica-tion as a diagnostic antigen.The diphtheria mutant toxin CRM197 is used in many conjugate vaccines.The synthetic crm 197 gene with codon optimization in pET28a was transformed into E.coli Origami B(DE3)cells.CRM197 was induced by isopro-pyl β-d-1-thiogalactopyranoside and high level accumulation of soluble CRM197 was purified using Ni-NTA spin columns and ion exchange chromatography.The purity of the final prepara-tion reached 95％.CRM197 was used to detect the concentra-tions of the anti-CRM197 antibody in serum samples of healthy volunteers of different ages.The proposed expression strategy yielded high production of CRM197,which could interfere with evaluations of induced immune interactions by glycan-CRM197 conjugates and prohibit application as a diagnostic antigen.

Objective:To explore the relationship between blood urea nitrogen to creatinine ratio and frailty in the elderly aged ≥65 years in 8 longevity areas in China.Methods:Participants were recruited from the Healthy Aging and Biomarkers Cohort Study. Based on baseline information about blood urea nitrogen and risk for frailty obtained at follow-up of the participants, blood urea nitrogen to creatinine ratio was classified according to quintiles, Cox proportional hazard regression models were used to analyze the association between blood urea nitrogen to creatinine ratio and frailty.Results:A total of 1 562 participants aged (81.0±17.0) years were included, in whom 814 (52.1%) were men, and 258 frailty events occurred during a mean follow-up of (3.73±1.43) years. Cox proportional hazards model showed that after adjusting for relevant confounders, compared with the participants in the lowest quintile group ( Q1), the risk for frailty decreased by 36%, 44%, and 40% in the participants in the third quintile group ( Q3), the fourth quintile group ( Q4) and the highest quintile group ( Q5) respectively [hazard ratio ( HR)=0.64, 95% CI: 0.43-0.94; HR=0.56, 95% CI: 0.38-0.84; HR=0.60, 95% CI: 0.41-0.88]. The risk for frailty decreased by 20% for every unit standard deviation increase in blood urea nitrogen to creatinine ratio ( HR=0.80, 95% CI: 0.70-0.91). Moreover, blood urea nitrogen to creatinine ratio and the risk for frailty showed a nearly linear dose-response relationship. Conclusions:The increase in blood urea nitrogen to creatinine ratio was associated with higher risk for frailty. Maintaining high blood urea nitrogen to creatinine ratio is important for the prevention of frailty in the elderly.

Humans ; Asthma/drug therapy* ; Biological Therapy

Objective: The docking and superantigen activity sites of staphylococcal enterotoxin-like W (SElW) and T cell receptor (TCR) were predicted, and its SElW was cloned, expressed and purified. Methods: AlphaFold was used to predict the 3D structure of SElW protein monomers, and the protein models were evaluated with the help of the SAVES online server from ERRAT, Ramachandran plot, and Verify_3D. The ZDOCK server simulates the docking conformation of SElW and TCR, and the amino acid sequences of SElW and other serotype enterotoxins were aligned. The primers were designed to amplify selw, and the fragment was recombined into the pMD18-T vector and sequenced. Then recombinant plasmid pMD18-T was digested with BamHⅠand Hind Ⅲ. The target fragment was recombined into the expression plasmid pET-28a(+). After identification of the recombinant plasmid, the protein expression was induced by isopropyl-beta-D- thiogalactopyranoside. The SElW expressed in the supernatant was purified by affinity chromatography and quantified by the BCA method. Results: The predicted three-dimensional structure showed that the SElW protein was composed of two domains, the amino-terminal and the carboxy-terminal. The amino-terminal domain was composed of 3 α-helices and 6 β-sheets, and the carboxy-terminal domain included 2 α-helices and 7 antiparallel β-sheets composition. The overall quality factor score of the SElW protein model was 98.08, with 93.24% of the amino acids having a Verify_3D score ≥0.2 and no amino acids located in disallowed regions. The docking conformation with the highest score (1 521.328) was selected as the analysis object, and the 19 hydrogen bonds between the corresponding amino acid residues of SElW and TCR were analyzed by PyMOL. Combined with sequence alignment and the published data, this study predicted and found five important superantigen active sites, namely Y18, N19, W55, C88, and C98. The highly purified soluble recombinant protein SElW was obtained with cloning, expression, and protein purification. Conclusions: The study found five superantigen active sites in SElW protein that need special attention and successfully constructed and expressed the SElW protein, which laid the foundation for further exploration of the immune recognition mechanism of SElW.
Humans ; Enterotoxins/genetics* ; Superantigens/genetics* ; Catalytic Domain ; Selenoprotein W/metabolism* ; Receptors, Antigen, T-Cell

Objective:To establish and validate an LC-MS/MS method for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in cerebrospinal fluid. Additionally, the consistency between this method and three mainstream detection methods was evaluated.Methods:This study involved method establishment, validation, and consistency evaluation. The N15 labeled β-amyloid protein was used as the internal standard. Extraction was performed using Waters MCX 96-wells solid phase extraction plate, and the eluent was collected to QuanRecovery MaxPeak 700 μl plate. At the positive ion mode, the multi-reaction ion monitoring mode based on electric spray ionization is chosen for the determination of CSF Aβ 1-42, Aβ 1-40, and Aβ 1-38. Referring to the CLSI C62-A and EP-15A3 guidelines, the method is evaluated and verified, including quantitation of limit (LOQ), linearity, recovery, precision, and accuracy. In addition, a total of 57 clinical residual CSF samples were collected and the concentrations of Aβ 1-42 and Aβ 1-40 were determined based on manual INNOTEST ELISA assay and Lumipulse G and Roche Elecsys fully automated biochemical analyzers. The comparison analysis and deviation evaluation were conducted by passing-bablok and Bland Altman methods.Results:The analysis time of this method is 8 min, and the LOQ of Aβ 1-42, Aβ1-40 and Aβ1-38 is 0.1 ng/ml, 0.5 ng/ml, and 0.1 ng/ml, respectively, and the linear range can meet the needs of clinical detection. Respectively, the recovery is 86.2%-93.8%, 100.9%-103.9% and 103.3%-107.1%; the total imprecision is 4.7%-7.4%, 3.5%-4.6% and 5.2%-10.9%. The measured values of Aβ 1-42 certified reference materials are all within the allowable uncertainty requirements. Moreover, the carryover rate of three analytes was all≤0.11%. In addition, the correlations of Aβ 1-42 and Aβ1-40 in CSF between this LC-MS/MS method and the INNOTEST ELISA method, Lumipulse G and Roche Elecsys fully automated biochemical analyzers were all deemed good, with correlation coefficient (r) ranging from 0.920 to 0.970. However, the measured values between the four methods were remarkably different.Conclusion:We established and validated a robust method based on LC-MS/MS technology for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in CSF. The method is accurate, simple, and suitable for clinical measurements. However, despite good correlations, there were substantial differences in the measurement results of Aβ 1-42 and Aβ 1-40 among different analytical platforms, indicating the need for further promotion of harmonization and standardization processes for AD classic biomarkers.

ObjectiveTo investigate the therapeutic effect of rhubarb decoction （RD） retention enema on a rat model of minimal hepatic encephalopathy （MHE） and its mechanism of action based on bile acid （BA） metabolomics. MethodsA total of 55 male Sprague－Dawley rats were randomly divided into blank group （NC group with 10 rats）， hepatic encephalopathy group （HE group with 15 rats）， MHE group with 15 rats， and MHE+rhubarb decoction treatment group （MHEY group with 15 rats）. Intraperitoneal injection of carbon tetrachloride （CCl₄） and thioacetamide （TAA） was performed to establish a rat model of MHE or HE， and the rats were sacrificed after 2 weeks of administration. The serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， alkaline phosphatase （ALP）， total bilirubin （TBil）， and total bile acid （TBA） and the concentration of blood ammonia were measured； the colonic contents were collected to measure pH value； liver and brain tissue samples were collected， and HE staining was used to observe the histopathological changes of the liver； the bile was collected， and liquid chromatography－mass spectrometry was used to perform BA－targeted metabolomics analysis. Continuous data were expressed as mean±standard deviation； a one－way analysis of variance was used for comparison between multiple groups， and the least significant difference t－test was used for further comparison between two groups. ResultsCompared with the NC group， the HE group and the MHE group had a significant increase in searching platform latency （after modelling and after administration） and a significant reduction in the number of platform crossings （all P<0.05）； compared with the MHE group， the MHEY group had a significant reduction in searching platform latency （after administration） and a significant increase in the number of platform crossings， and the HE group had a significant increase in searching platform latency and a significant reduction in the number of platform crossings （all P<0.05）. Compared with the NC group， the HE group and the MHE group had significant increases in AST， ALT， ALP， TBil， TBA， blood ammonia， and colon pH value （all P<0.05）； compared with the MHE group， the MHEY group had significant reductions in AST， ALT， ALP， TBil， TBA， blood ammonia， and colon pH value （all P<0.05）， and the HE group had significant increases in AST， ALT， ALP， TBil， TBA， blood ammonia， and colon pH value （all P<0.05）. The MHE group had significantly lower TBA， primary BA， and secondary BA than the NC group （all P<0.05）； compared with the MHE group， the HE group had significantly lower TBA and primary BA （all P<0.05）， and the MHEY group had significantly higher TBA and primary BA （all P<0.05）. Compared with the NC group， the MHE group had significant reductions in GCDCA， GUDCA， GHDCA， TCDCA， TUDCA， GLCA， and TLCA （all P<0.05） and significant increases in γ－MCA， THCA， 7－KDCA， AlloLCA， and α－MCA （all P<0.05）， and compared with the MHE group， the MHEY group had significant increases in THDCA， TMCA， TCDCA， TUDCA， and TLCA （all P<0.05）. ConclusionRD retention enema can improve liver injury and cognitive function in a rat model of MHE induced by CCl₄ and TAA by regulating the enterohepatic circulation of BA， possibly by increasing the synthesis of taurine－binding BA.

Humans ; Diabetes Mellitus, Type 2/epidemiology* ; Air Pollution/adverse effects* ; Air Pollutants/toxicity* ; Risk Assessment ; Particulate Matter ; Environmental Exposure

OBJECTIVE: Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research. In this report, two distinguished phenotypic isolates (CJ1Z, flhA mutant strain, lawn; CJ2S, flhA complemented strain, normal colony) appeared during laboratory passages for NCTC11168. METHODS: Phenotypic assessments, including motility plates, transmission electron microscopy, biofilm formation assay, autoagglutination assay, and genome re-sequencing for these two isolates (CJ1Z, flhA mutant strain; CJ2S, flhA complemented strain) were carried out in this study. RESULTS: Transmission electron microscopy revealed that the flagellum was lost in CJ1Z. Phenotypic assessments and genome sequencing of the two isolates were performed in this study. The capacity for biofilm formation, colony auto-agglutination, and isolate motility was reduced in the mutant CJ1Z. Comparative genomic analysis indicated a unique native nucleotide insertion in flhA (nt, 2154) that caused the I719Y and I720Y mutations and early truncation in flhA. CONCLUSION FlhA has been found to influence the expression of flagella in C. jejuni. To the best of our knowledge, this is the first study to describe the function of the C-terminal of this protein.
Campylobacter jejuni/genetics* ; Bacterial Proteins/metabolism* ; Mutation ; Biological Variation, Population

Objective: To understand the use of psychoactive substances and its related factors in men who have sex with men (MSM) in Tianjin. Methods: A cross-sectional survey was conducted in MSM recruited in Tianjin by snowball sampling from September 2017 to December 2020, the information about their social demographic information, use of psychoactive substances and behavioral characteristics were collected, meanwhile the blood samples were taken from them for HIV/syphilis detections. Multivariate logistic regression was used to explore related factors about psychoactive substances use. Results: A total of 9 218 MSM were included in the study, in whom 43.5% (4 013/9 218) had ever used psychoactive substances, including 92.6% (3 718/4 013)who used Rush and 17.2% (692/4 013) who used multi substances. Multivariate analysis showed that, the OR of psychoactive substances use in MSM who were in Han ethnic group was 0.68 (95%CI:0.51-0.91) compared with those who were in minor ethnic group; the OR of psychoactive substances use in MSM who were married or cohabited, divorced or widowed were 0.65 (95%CI: 0.57-0.71), 0.80 (95%CI: 0.65-0.97) respectively compared with those who were unmarried; the OR of psychoactive substances use in MSM who had the first homosexual sex at age of ≥30 years was 0.57 (95%CI: 0.44-0.74) compared with those who had the first homosexual sex at age of <30 years; the OR of psychoactive substances use in local MSM in Tianjin was 1.12 (95%CI: 1.03-1.23) compared with those who were not local residents in Tianjin; the OR of psychoactive substances use in MSM with education level of college or above was 1.29 (95%CI: 1.12-1.49) compared with those with education level of junior middle school or below; the OR of psychoactive substances use in MSM who had anal sex in the past six months was 1.93 (95%CI: 1.34-2.77) compared with those who had no anal sex; the OR of psychoactive substances use in MSM who had >2 homosexual partners in the last week was 1.62 (95%CI: 1.41-1.87) compared with those who had ≤2 homosexual partners; the OR of psychoactive substances use in MSM who had homosexual commercial sex in the past six months was 1.99 (95%CI: 1.62-2.45) compared with those who had no homosexual commercial sex; the OR of psychoactive substances use in MSM who had sexually transmitted diseases in the last year was 2.39 (95%CI: 1.82-3.12) compared with those who had no sexually transmitted diseases and the OR of psychoactive substances use in MSM who received peer education services in the last year was 1.63 (95%CI: 1.50-1.78) compared with those who received no peer education services. Conclusion: The prevalence of psychoactive substances use is high in MSM in Tianjin, and there are many influencing factors. It is necessary to conduct targeted interventions according to the influencing factors.
Adult ; China/epidemiology* ; Cross-Sectional Studies ; HIV Infections/epidemiology* ; Homosexuality, Male ; Humans ; Male ; Prevalence ; Risk Factors ; Sex Work ; Sexual Behavior ; Sexual and Gender Minorities ; Surveys and Questionnaires ; Syphilis/epidemiology*

The high incidence of cardiovascular diseases is a serious threat to human health, and endovascular surgery has become the standard treatment for most interventional cardiovascular diseases. The robotassisted endovascular surgery system further enhances surgeons' ability to perform minimally invasive endovascular procedures in interventional cardiology. This study presents a new robotic technique for coronary intervention from the perspective of clinical application. Aiming at clinical application scenarios, this scheme proposed an intuitive guide wire catheter mechanism design, which accurately and perfectly simulates the doctor's hand movements, realizes the positive and negative direction translation of the guide wire catheter, accurate torque control of the guide wire rotation and locking. The results of animal test showed that the R-One^TM has a high degree of dexterity, accuracy and stability,and meets the clinical needs.
Animals ; Cardiovascular Diseases ; Catheterization ; Equipment Design ; Robotic Surgical Procedures ; Robotics