Immobilized enzyme-based enzyme electrode biosensors, characterized by high sensitivity and efficiency, strong specificity, and compact size, demonstrate broad application prospects in life science research, disease diagnosis and monitoring, etc. Immobilization of enzyme is a critical step in determining the performance (stability, sensitivity, and reproducibility) of the biosensors. Random immobilization (physical adsorption, covalent cross-linking, etc.) can easily bring about problems, such as decreased enzyme activity and relatively unstable immobilization. Whereas, directional immobilization utilizing amino acid residue mutation, affinity peptide fusion, or nucleotide-specific binding to restrict the orientation of the enzymes provides new possibilities to solve the problems caused by random immobilization. In this paper, the principles, advantages and disadvantages and the application progress of enzyme electrode biosensors of different directional immobilization strategies for enzyme molecular sensing elements by specific amino acids (lysine, histidine, cysteine, unnatural amino acid) with functional groups introduced based on site-specific mutation, affinity peptides (gold binding peptides, carbon binding peptides, carbohydrate binding domains) fused through genetic engineering, and specific binding between nucleotides and target enzymes (proteins) were reviewed, and the application fields, advantages and limitations of various immobilized enzyme interface characterization techniques were discussed, hoping to provide theoretical and technical guidance for the creation of high-performance enzyme sensing elements and the manufacture of enzyme electrode sensors.

Objective To investigate the association of triglyceride-glucose index(TyG)with non-alcoholic fatty liver disease(NAFLD)and its diagnostic value for NAFLD in non-obese individuals.Methods We retrospectively collected the data of non-obese individuals(BMI<25 kg/m2)undergoing routine health examination at Second Affiliated Hospital of Xi'an Jiaotong University between May,2020 and December,2023,who all received abdominal ultrasound examination for NAFLD screening.The nonlinear relationship between TyG and non-obese NAFLD was explored using restricted cubic splines(RCS),and LASSO regression was used for variable screening;the correlation between TyG and NAFLD risk was analyzed using multivariate logistic regression.The diagnostic value of TyG for non-obese NAFLD was assessed using receiver-operating characteristic(ROC)curves and sensitivity analysis.Results A total of 3723 non-obese subjects were enrolled in this study,including 432(11.6%)patients with NAFLD.Compared with the healthy individuals,the patients with NAFLD had significant elevations of systolic and diastolic blood pressures,total cholesterol,triglycerides,LDL-C,blood uric acid,fasting blood glucose,and TyG index and a decreased HDL-C level(P<0.05).Multivariate logistic regression revealed that for each one-unit increase of TyG,the risk of non-obese NAFLD increased by 2.2 folds(OR=3.22,95%CI:2.53-4.12,P<0.001).Compared with a TyG index in the lowest quartile Q1,a TyG index in the Q2,Q3 and Q4 quartiles was associated with an increased risk of NAFLD by 1.52 folds(OR=2.52,95%CI:1.20-5.95),3.56 folds(OR=4.56,95%CI:2.28-10.46),and 8.66-folds(OR=9.66,95%CI:4.83-22.18),respectively.The RCS curve demonstrated a significant linear correlation between TyG index and non-obese NALFD risk(P for nonlinear=0.019).For diagnosing non-obese NALFD,TyG index had an area under ROC curve of 0.819 with a sensitivity of 78.0%and a specificity of 71.2%.Conclusion An increase of TyG index is correlated with increased risks of NAFLD in non-obese individuals and can serve as an indicator for screening early NAFLD in healthy individuals.

Objective To investigate the effects of Erhuang Quzhi Granules combined with Silibinin Capsules on fatty liver index,inflammatory factors and autophagy-related gene levels in patients with nonalcoholic fatty liver disease(NAFLD).Methods A total of 126 patients with NAFLD of phlegm blended with blood stasis type were randomly divided into control group and observation group,with 63 cases in each group.The control group was treated with oral use of Silibinin Capsules,and the observation group was treated with oral use of Erhuang Quzhi Granules on the basis of treatment for the control group.The course of treatment lasted for 3 months.Before and after treatment,the two groups were observed in the changes of fatty liver index,and the levels of inflammatory factors of interleukin 6(IL-6)and tumor necrosis factor alpha(TNF-α),liver function and blood lipid indicators of alanine aminotransferase(ALT),aspartate aminotransferase(AST),γ-glutamyl transpeptidase(GGT),total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C),and autophagy-related genes of autophagy-related gene 7(ATG7)and myosin-like BCL2 binding protein(Beclin 1).After treatment,the clinical efficacy and safety of the two groups were evaluated.Results(1)After 3 months of treatment,the total effective rate of the observation group was 90.48％(57/63),and that of the control group was 71.43％(45/63).The intergroup comparison(tested by chi-square test)showed that the efficacy of the observation group was significantly superior to that of the control group(P＜0.01).(2)After treatment,the fatty liver index of the two groups was significantly decreased compared with that before treatment(P＜0.05),and the decrease of fatty liver index in the observation group was significantly superior to that in the control group(P＜0.01).(3)After treatment,the serum levels of inflammatory factors of IL-6 and TNF-α in the two groups were significantly lower than those before treatment(P＜0.05),and the decrease of serum IL-6 and TNF-α levels in the observation group was significantly superior to that in the control group(P＜0.05).(4)AAfter treatment,the serum levels of liver function indicators of ALT,AST and GGT in the two groups were significantly lower than those before treatment(P＜0.05),and the decrease of serum ALT,AST and GGT levels in the observation group was significantly superior to that in the control group(P＜0.05).(5)After treatment,the serum levels of blood lipids of TG,TC and LDL-C in the two groups were significantly lower than those before treatment(P＜0.05),and the serum HDL-C level was significantly higher than that before treatment(P＜0.05).The decrease of serum TG,TC and LDL-C levels and the increase of serum HDL-C level in the observation group were significantly superior to those in the control group(P＜0.05).(6)After treatment,the serum levels of autophagy-related genes of ATG7 and Beclin 1 in the two groups were significantly higher than those before treatment(P＜0.05),and the increase of serum ATG7 and Beclin 1 levels in the observation group was significantly superior to that in the control group(P＜0.05).(7)During the medication,no liver or kidney function damage or serious adverse reactions were found in the two groups.Conclusion Erhuang Quzhi Granules combined with Silibinin Capsules are effective for the treatment of NAFLD patients with phlegm blended with blood stasis type,which is helpful to relieve the symptoms of fatty liver,reduce the levels of inflammatory factors,improve liver function and blood lipid levels,and regulate the expression of autophagy-related genes.

Aim To explore the improvement effect of Bazi Bushen capsule on thymic degeneration in SAMP6 mice and the possible mechanism.Methods Twenty 12 week old male SAMP6 mice were randomly divided into the model group(SAMP6)and the Bazi Busheng capsule treatment group(SAMP6+BZBS).Ten SAMR1 mice were assigned to a homologous control group(SAMR1).The SAMP6+BZBS group was oral-ly administered Bazi Bushen capsule suspension(2.8 g·kg-1)daily,while the other two groups were orally administered an equal amount of distilled water.After nine weeks of administration,the morphology of the thymus in each group was observed and the thymus in-dex was calculated;HE staining was used to observe the structural changes of thymus tissue;SA-β-gal stai-ning was used to detect thymic aging;flow cytometry was used to detect the proportion of thymic CD3+T cells in each group;Western blot was used to detect the levels of p16,Bax,Bcl-2,and cleaved caspase-3 proteins in thymus;immunofluorescence was applied to detect the proportion of cortical thymic epithelial cells in each group;ELISA was employed to detect IL-7 lev-els in thymus.Results Compared with the SAMP6 group,the thymic index of the SAMP6+BZBS group significantly increased(P＜0.05);the disordered thy-mic structure was significantly improved;the positive proportion of SA-β-gal staining significantly decreased(P＜0.01);the proportion of CD3+T cells apparently increased(P＜0.05);the level of p16 protein signifi-cantly decreased(P＜0.05);the level of Bcl-2 pro-tein significantly increased(P＜0.05),while the lev-el of cleaved caspase-3 protein markedly decreased(P＜0.05);the proportion of cortical thymic epithelial cells evidently increased;the level of IL-7 significantly increased(P＜0.01).Conclusions Bazi Bushen capsule can delay thymic degeneration,inhibit cell ap-optosis in thymus and promote thymic cell development in SAMP6 mice,which may be related to increasing the proportion of cortical thymic epithelial cells and promoting IL-7 secretion.

Objective To investigate the changing distribution and antibiotic resistance profiles of clinical isolates of Staphylococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Staphylococcus according to the unified protocol of CHINET(China Antimicrobial Surveillance Network)using disk diffusion method and commercial automated systems.The CHINET antimicrobial resistance surveillance data from 2015 to 2021 were interpreted according to the 2021 CLSI breakpoints and analyzed using WHONET 5.6.Results During the period from 2015 to 2021,a total of 204,771 nonduplicate strains of Staphylococcus were isolated,including 136,731(66.8％)strains of Staphylococcus aureus and 68,040(33.2％)strains of coagulase-negative Staphylococcus(CNS).The proportions of S.aureus isolates and CNS isolates did not show significant change.S.aureus strains were mainly isolated from respiratory specimens(38.9±5.1)％,wound,pus and secretions(33.6±4.2)％,and blood(11.9±1.5)％.The CNS strains were predominantly isolated from blood(73.6±4.2)％,cerebrospinal fluid(12.1±2.5)％,and pleural effusion and ascites(8.4±2.1)％.S.aureus strains were mainly isolated from the patients in ICU(17.0±7.3)％,outpatient and emergency(11.6±1.7)％,and department of surgery(11.2±0.9)％,whereas CNS strains were primarily isolated from the patients in ICU(32.2±9.7)％,outpatient and emergency(12.8±4.7)％,and department of internal medicine(11.2±1.9)％.The prevalence of methicillin-resistant strains was 32.9％in S.aureus(MRSA)and 74.1％in CNS(MRCNS).Over the 7-year period,the prevalence of MRSA decreased from 42.1％to 29.2％,and the prevalence of MRCNS decreased from 82.1％to 68.2％.MRSA showed higher resistance rates to all the antimicrobial agents tested except trimethoprim-sulfamethoxazole than methicillin-susceptible S.aureus(MSSA).Over the 7-year period,MRSA strains showed decreasing resistance rates to gentamicin,rifampicin,and levofloxacin,MRCNS showed decreasing resistance rates to gentamicin,erythromycin,rifampicin,and trimethoprim-sulfamethoxazole,but increasing resistance rate to levofloxacin.No vancomycin-resistant strains were detected.The prevalence of linezolid-resistant MRCNS increased from 0.2％to 2.3％over the 7-year period.Conclusions Staphylococcus remains the major pathogen among gram-positive bacteria.MRSA and MRCNS were still the principal antibiotic-resistant gram-positive bacteria.No S.aureus isolates were found resistant to vancomycin or linezolid,but linezolid-resistant strains have been detected in MRCNS isolates,which is an issue of concern.

Objective To investigate the role and mechanism of epithelial-mesenchymal transition(EMT)in a rat model of bronchopulmonary dysplasia(BPD).Methods The experiment consisted of two parts.(1)Forty-eight preterm rats were randomly divided into a normoxia group and a hyperoxia group,with 24 rats in each group.The hyperoxia group was exposed to 85%oxygen to establish a BPD model,while the normoxia group was kept in room air at normal pressure.Lung tissue samples were collected on days 1,4,7,and 14 of the experiment.(2)Rat type II alveolar epithelial cells(RLE-6TN)were randomly divided into a normoxia group(cultured in air)and a hyperoxia group(cultured in 95%oxygen),and cell samples were collected 12,24,and 48 hours after hyperoxia exposure.Hematoxylin-eosin staining was used to observe alveolarization in preterm rat lungs,and immunofluorescence was used to detect the co-localization of surfactant protein C(SPC)and α-smooth muscle actin(α-SMA)in preterm rat lung tissue and RLE-6TN cells.Quantitative real-time polymerase chain reaction and protein immunoblotting were used to detect the expression levels of EMT-related mRNA and proteins in preterm rat lung tissue and RLE-6TN cells.Results(1)Compared with the normoxia group,the hyperoxia group showed blocked alveolarization and simplified alveolar structure after 7 days of hyperoxia exposure.Co-localization of SPC and α-SMA was observed in lung tissue,with decreased SPC expression and increased α-SMA expression in the hyperoxia group at 7 and 14 days of hyperoxia exposure compared to the normoxia group.In the hyperoxia group,the mRNA and protein levels of TGF-β1,α-SMA,and N-cadherin were increased,while the mRNA and protein levels of SPC and E-cadherin were decreased at 7 and 14 days of hyperoxia exposure compared to the normoxia group(P<0.05).(2)SPC and α-SMA was observed in RLE-6TN cells,with decreased SPC expression and increased α-SMA expression in the hyperoxia group at 24 and 48 hours of hyperoxia exposure compared to the normoxia group.Compared to the normoxia group,the mRNA and protein levels of SPC and E-cadherin in the hyperoxia group were decreased,while the mRNA and protein levels of TGF-β1,α-SMA,and E-cadherin in the hyperoxia group increased at 48 hours of hyperoxia exposure(P<0.05).Conclusions EMT disrupts the tight connections between alveolar epithelial cells in a preterm rat model of BPD,leading to simplified alveolar structure and abnormal development,and is involved in the development of BPD.

Objective To explore the association between visceral adiposity index(VAI)and nonalcoholic fatty liver disease(NAFLD)in lean population and the predictive value of VAI.Methods A total of 2 576 healthy subjects,body mass index(BMI)＜24 kg/m2,from The Second Affiliated Hospital of Xi'an Jiaotong University from June 2020 to May 2021 were randomly included and divided into lean NAFLD(n=213)and healthy control group(n=2 363).According to the VAI quartiles,they were divided into Q1-Q4 groups from low to high.The differences in biochemical parameters and the prevalence of NAFLD were compared among groups.The correlation between VAI and lean NAFLD was analyzed with restricted cubic spline(RCS),and the predictive value of VAI was explored by Logistic regression and receiver operating characteristic(ROC)curve.Results A total of 2 576 participants were included,and the prevalence of lean NAFLD was 8.3％(213 cases).The mean age,male ratio,BMI and waist circumference(WC)from group Q1 to group Q4 were significantly increased in a dose-response relationship(all P＜0.001).Compared with those in group Q1,systolic blood pressure,diastolic blood pressure,white blood cell count,hemoglobin concentration,alanine aminotransferase,aspartate aminotransferase,γ-glutamyl transpeptidase,alkaline phosphatase,total cholesterol,triglyceride,low-density lipoprotein cholesterol,blood uric acid,and fasting blood glucose levels in groups Q2 to Q4 were significantly increased,while direct bilirubin and high-density lipoprotein cholesterol levels were gradually decreased(both P＜0.001).The prevalence rate of NAFLD in groups Q1-Q4 was 0.6％,3.3％,7.0％and 22.2％,respectively(P＜0.001).RCS showed that the risk of NAFLD in lean population rose significantly with the increase of VAI(P＜0.001),and there was a nonlinear relationship between them(P for nonlinear＜0.001).Logistic regression showed that after adjusting other confounding factors,the risk of lean NAFLD in groups Q2,Q3 and Q4 was still 2.926 times(95％CI:0.971-8.811),3.435 times(95％CI:1.154-10.230),and 5.920 times(95％CI:1.873-18.719)that Q1 group.ROC curve showed that VAI had a good predictive value for lean NAFLD,with area under the curve of 0.815,critical value of 1.532,diagnostic sensitivity of 77.9％and specificity of 72.8％,which were better than BMI and WC.Conclusion VAI is significantly associated with the risk of NAFLD in lean population,and thus has a good predictive value.It can be used for early screening and diagnosis of lean NAFLD.

Objective To investigate the risk factors for diabetic ketoacidosis(DKA)in children/adolescents with type 1 diabetes mellitus(T1DM)and to establish a model for predicting the risk of DKA.Methods A retrospective analysis was performed on 217 children/adolescents with T1DM who were admitted to General Hospital of Ningxia Medical University from January 2018 to December 2021.Among the 217 children/adolescents,169 cases with DKA were included as the DKA group and 48 cases without DKA were included as the non-DKA group.The risk factors for DKA in the children/adolescents with T1DM were analyzed,and a nomogram model was established for predicting the risk of DKA in children/adolescents with T1DM.Results For the 217 children/adolescents with T1DM,the incidence rate of DKA was 77.9%(169/217).The multivariate logistic regression analysis showed that high levels of random blood glucose,hemoglobin A1c(HbA1c),blood ketone body,and triglyceride on admission were closely associated with the development of DKA in the children/adolescents with T1DM(OR=1.156,3.203×1015,20.131,and 9.519 respectively;P<0.05).The nomogram prediction model had a C-statistic of 0.95,with a mean absolute error of 0.004 between the risk of DKA predicted by the nomogram model and the actual risk of DKA,indicating that the model had a good overall prediction ability.Conclusions High levels of random blood glucose,HbA1c,blood ketone body,and triglyceride on admission are closely associated with the development of DKA in children/adolescents with T1DM,and targeted intervention measures should be developed to reduce the risk of DKA.

Objective To investigate the association of triglyceride-glucose index(TyG)with non-alcoholic fatty liver disease(NAFLD)and its diagnostic value for NAFLD in non-obese individuals.Methods We retrospectively collected the data of non-obese individuals(BMI<25 kg/m2)undergoing routine health examination at Second Affiliated Hospital of Xi'an Jiaotong University between May,2020 and December,2023,who all received abdominal ultrasound examination for NAFLD screening.The nonlinear relationship between TyG and non-obese NAFLD was explored using restricted cubic splines(RCS),and LASSO regression was used for variable screening;the correlation between TyG and NAFLD risk was analyzed using multivariate logistic regression.The diagnostic value of TyG for non-obese NAFLD was assessed using receiver-operating characteristic(ROC)curves and sensitivity analysis.Results A total of 3723 non-obese subjects were enrolled in this study,including 432(11.6%)patients with NAFLD.Compared with the healthy individuals,the patients with NAFLD had significant elevations of systolic and diastolic blood pressures,total cholesterol,triglycerides,LDL-C,blood uric acid,fasting blood glucose,and TyG index and a decreased HDL-C level(P<0.05).Multivariate logistic regression revealed that for each one-unit increase of TyG,the risk of non-obese NAFLD increased by 2.2 folds(OR=3.22,95%CI:2.53-4.12,P<0.001).Compared with a TyG index in the lowest quartile Q1,a TyG index in the Q2,Q3 and Q4 quartiles was associated with an increased risk of NAFLD by 1.52 folds(OR=2.52,95%CI:1.20-5.95),3.56 folds(OR=4.56,95%CI:2.28-10.46),and 8.66-folds(OR=9.66,95%CI:4.83-22.18),respectively.The RCS curve demonstrated a significant linear correlation between TyG index and non-obese NALFD risk(P for nonlinear=0.019).For diagnosing non-obese NALFD,TyG index had an area under ROC curve of 0.819 with a sensitivity of 78.0%and a specificity of 71.2%.Conclusion An increase of TyG index is correlated with increased risks of NAFLD in non-obese individuals and can serve as an indicator for screening early NAFLD in healthy individuals.

AIM To study the Chemical constituents from Rhinacanthus nasutus(L.)Kurz and their in vitro antitumor and lipid-lowering activities.METHODS The ethyl acetate fraction from R.nasutus was isolated and purified by normal phase,reverse phase silica gel column and semi-preparative HPLC,then the structures of obtained compounds were identified by physicochemical properties and spectral data.The in vitro anti-tumor activity was determined by MTT assay,and the in vitro lipid-lowering activity was evaluated by oleic acid-induced HepG2 high-fat cell model.RESULTS Twenty compounds were isolated and identified as rhinacanthin A(1),rhinacanthin B(2),rhinacanthin C(3),rhinacanthin D(4),rhinacanthin E(5),rhinacanthin M(6),rhinacanthin N(7),rhinacanthin Q(8),rhinacanthin T(9),rhinacanthone(10),β-sitosterol(11),gallic acid(12),vanillic acid(13),syringic acid(14),lapachol(15),umbelliferone(16),sambucunlin A(17),17α,21-dihydroxy-1,4-pregnadiene-3,11,20-trione,21-acetate(18),1,8-dihydroxyanthraquinone(19),2,6-dimethoxy-1,4-benzoquinone(20).Compounds 3 and 7 inhibited the proliferation of HepG2,Hela,A549 and H22 tumor cells with IC50 values of(0.66±0.17)-(3.22±0.49)μmol/L in a time-and concentration-dependent manner.Compounds 3,7 and 9 had a lipid clearance rate of more than 50%in oleic acid-induced HepG2 high-fat cells.CONCLUSION Compounds 16-20 are isolated from this plant for the first time.Compounds 3 and 7 have good in vitro anti-tumor activities,and 3,7,9 have good in vitro lipid-lowering activities.