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 protective effect of dexmedetomidine(Dex)pretreatment on myocardial ischemia-reperfusion mice and the effect of Nod-like receptor protein 3(NLRP3)inflammatory signaling pathway.Methods C57BL/6J mice were randomly divided into sham group(only threading without ligation),model group(recovery after ligation of left anterior descending coronary artery),positive group(modeling after intraperitoneal injection of 1 mg·kg-1 trimetazidine),Dex group(modeling after intraperitoneal injection of 20 μg·kg-1 dexmedetomidine),MCC950 group(modeling after intraperitoneal injection of 10 mg·kg-1 NLRP3 inhibitor MCC950),12 mice in each group.Cardiac function indexes were detected at 24 h after reperfusion,the expression level of related proteins in myocardial tissue was detected by Western blot,enzyme-linked immunosorbent assay(ELISA)was used to detect the expression level of serum factor,myocardial antioxidant index was detected by kit method,and apoptosis was detected by Tunel method.Results The NLRP3 protein expression levels of sham group,model group,positive group,Dex group and MCC950 group were 0.31±0.05,1.06±0.07,0.52±0.05,0.65±0.07 and 0.39±0.04,respectively;the expression levels of apoptosis-associated granuloid protein(ASC)were 0.27±0.08,0.88±0.09,0.46±0.05,0.59±0.07 and 0.34±0.04,respectively;CK-MB levels were(25.64±2.94),(102.08±7.04),(49.61±7.70),(60.86±5.24)and(63.24±5.38)U·L-1,respectively;IL-6 levels were(104.78±10.73),(231.54±15.56),(158.20±16.54),(165.10±14.77)and(141.17±14.08)pg·mL-1,respectively;Tunel positive cell rates were(4.34±0.16)％,(25.98±1.58)％,(8.74±0.93)％,(11.06±1.07)％and(9.19±0.88)％,respectively.Sham group were compared with model group;Dex group and MCC950 group were compared with model group,the above indexes were statistically significant(all P＜0.05).Conclusion Dexmedetomidine preconditioning may prevent ischemia-reperfusion myocardial injury by inhibiting NLRP3/ASC/caspase-1 inflammatory pathway,inflammatory response and myocardial cell apoptosis.

The occurrence of benign prostate hyperplasia(BPH)was related to disrupted sex steroid hormones,and metformin(Met)had a clinical response to sex steroid hormone-related gynaecological disease.How-ever,whether Met exerts an antiproliferative effect on BPH via sex steroid hormones remains unclear.Here,our clinical study showed that along with prostatic epithelial cell(PEC)proliferation,sex steroid hormones were dysregulated in the serum and prostate of BPH patients.As the major contributor to dysregulated sex steroid hormones,elevated dihydrotestosterone(DHT)had a significant positive rela-tionship with the clinical characteristics of BPH patients.Activation of adenosine 5'-monophosphate(AMP)-activated protein kinase(AMPK)by Met restored dysregulated sex steroid hormone homeostasis and exerted antiproliferative effects against DHT-induced proliferation by inhibiting the formation of androgen receptor(AR)-mediated Yes-associated protein(YAP1)-TEA domain transcription factor(TEAD4)heterodimers.Met's anti-proliferative effects were blocked by AMPK inhibitor or YAP1 over-expression in DHT-cultured BPH-1 cells.Our findings indicated that Met would be a promising clinical therapeutic approach for BPH by inhibiting dysregulated steroid hormone-induced PEC proliferation.

The incidence of intrahepatic cholangiocarcinoma (ICC) continues to rise, and there are no effective drugs to treat it. The immune microenvironment plays an important role in the development of ICC and is currently a research hotspot. Icaritin (ICA) is an innovative traditional Chinese medicine for the treatment of advanced hepatocellular carcinoma. It is considered to have potential immunoregulatory and anti-tumor effects, which is potentially consistent with the understanding of "Fuzheng" in the treatment of tumor in traditional Chinese medicine. However, whether ICA can be used to treat ICC has not been reported. Therefore, in this study, sgp19/kRas, an in situ ICC mouse model with intact immune system, was selected to evaluate the efficacy of ICA in the treatment of ICC in vivo for the first time, and the effects of ICA on the tumor immune microenvironment of ICC mice were analyzed by flow cytometry. This experiment was approved by the Experimental Animal Ethics Committee of Capital Medical University (approval number: AEEI-2023-138). In this study, sgp19/kRas ICC mouse model was treated with oral gavage of 100 mg·kg^-1 ICA. We found that ICA significantly inhibited tumor growth and tumor cell proliferation in the sgp19/kRas ICC mouse model after 3 weeks of treatment. Flow cytometry analysis indicated that ICA treatment markedly reduced the proportion of M2 macrophages and increased the number of CD3⁺CD4⁺ T cells. In vitro experiments demonstrated that ICA promoted macrophage polarization towards the M1 phenotype while inhibiting polarization towards the M2 phenotype. Furthermore, transcriptomic analysis suggested that ICA enhanced Toll-like receptor 9 (TLR9) expression, influencing macrophage nitric oxide metabolism synthesis pathways and receptor-related activities, thereby regulating macrophage polarization. In summary, this study demonstrates that ICA treatment significantly delays tumor progression in sgp19/kRas ICC mouse models. Mechanistically, ICA may achieve its anti-ICC effects by upregulating TLR9 receptor expression levels, promoting macrophage polarization towards the M1 phenotype, and altering the tumor immune microenvironment.

Objective:To evaluate the efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with secondary acute myeloid leukemia (sAML) .Methods:In this multicenter, retrospective clinical study, adult patients aged ≥18 years who underwent allo-HSCT for sAML at four centers of the Zhejiang Hematopoietic Stem Cell Transplantation Collaborative Group from January 2014 to November 2022 were included, and the efficacy and prognostic factors of allo-HSCT were analyzed.Results:A total of 95 patients were enrolled; 66 (69.5%) had myelodysplastic syndrome-acute myeloid leukemia (MDS-AML) , 4 (4.2%) had MDS/MPN-AML, and 25 (26.3%) had therapy-related AML (tAML) . The 3-year CIR, LFS, and overall survival (OS) rates were 18.6% (95% CI 10.2%-27.0%) , 70.6% (95% CI 60.8%-80.4%) , and 73.3% (95% CI 63.9%-82.7%) , respectively. The 3-year CIRs of the M-AML group (including MDS-AML and MDS/MPN-AML) and the tAML group were 20.0% and 16.4%, respectively ( P=0.430) . The 3-year LFSs were 68.3% and 75.4%, respectively ( P=0.176) . The 3-year OS rates were 69.7% and 75.4%, respectively ( P=0.233) . The 3-year CIRs of the groups with and without TP53 mutations were 60.0% and 13.7%, respectively ( P=0.003) ; the 3-year LFSs were 20.0% and 76.5%, respectively ( P=0.002) ; and the 3-year OS rates were 40.0% and 77.6%, respectively ( P=0.002) . According to European LeukmiaNet 2022 (ELN2022) risk stratification, the 3-year CIRs of patients in the low-, intermediate-, and high-risk groups were 8.3%, 17.8%, and 22.6%, respectively ( P=0.639) . The three-year LFSs were 91.7%, 69.5%, and 65.6%, respectively ( P=0.268) . The 3-year OS rates were 91.7%, 71.4%, and 70.1%, respectively ( P=0.314) . Multivariate analysis revealed that advanced disease at allo-HSCT and TP53 mutations were independent risk factors for CIR, LFS, and OS. Conclusion:There was no significant difference in the prognosis of patients who underwent allo-HSCT among the MDS-AML, MDS/MPN-AML, and tAML groups. Advanced disease at transplantation and TP53 mutations were poor prognostic factors. ELN2022 risk stratification had limited value for predicting the prognosis of patients with sAML following allo-HSCT.

Objective To investigate the short-term efficacy and safety of chemotherapy induced by nimotuzumab(NTZ)combined with TP regimen and sequential concurrent chemoradiotherapy in patients with epidermal growth factor receptor positive(EGFR-positive)locally advanced nasopharyngeal carcinoma.Methods A total of 48 patients with stage Ⅲ to Ⅳ A nasopharyngeal carcinoma in Guizhou Provincial People's Hospital from January 2020 to December 2022 were prospectively enrolled,and were randomized into two groups:NTP(NTZ+docetaxel/albumin-paclitaxel+cisplatin)group and TP(Docetaxel/albumin-paclitaxel+cisplatin)group(24 cases per group)by random number table method.After 2 or 3 cycles of induction chemotherapy in NTP group,NTZ was sequentially used in combination with cisplatin for concurrent chemoradiotherapy.Immunohistochemistry was used to detect the EGFR expression level,exploring EGFR expression intensity and the therapeutic effect of NTZ in NTP group patients.Meanwhile,short-term efficacy,withdrawal rate and toxic side effects were compared between the two groups after induction chemotherapy.Results In NTP group,the positive expression rate of EGFR was 100％,and EGFR expression intensity significantly correlated with the efficacy of NTZ-combined induction therapy(P<0.05).After induction chemotherapy,the objective response rate(ORR)of cervical lymph nodes in NTP group was significantly higher than that in TP group(75％vs.45.8％,P=0.039).The primary lesion ORR and overall(primary lesion and cervical lymph node)ORR showed no significant difference between the two groups(P>0.05).Comparison of adverse reactions between the two groups during induction therapy:leukopenia and gastrointestinal reaction in NTP group were lower than those in TP group(P<0.05),but rash was higher than those in TP group(P<0.05).There was no significant difference in liver function,hemoglobin and thrombocytopenia between two groups(P>0.05).Conclusions EGFR expression intensity varies in nasopharyngeal carcinoma tissues,with higher levels indicating greater clinical benefit of combined induction therapy with NTZ.NTZ combined with TP induction regimen demonstrates good short-term efficacy and safety for cervical lymph nodes in patients with locally advanced nasopharyngeal carcinoma.

Objective To study the in vitro expression of three phenylalanine hydroxylase(PAH)mutants(p.R243Q,p.R241C,and p.Y356X)and determine their pathogenicity.Methods Bioinformatics techniques were used to predict the impact of PAH mutants on the structure and function of PAH protein.Corresponding mutant plasmids of PAH were constructed and expressed in HEK293T cells.Quantitative reverse transcription polymerase chain reaction was used to measure the mRNA expression levels of the three PAH mutants,and their protein levels were assessed using Western blot and enzyme-linked immunosorbent assay.Results Bioinformatics analysis predicted that all three mutants were pathogenic.The mRNA expression levels of the p.R243Q and p.R241C mutants in HEK293T cells were similar to the mRNA expression level of the wild-type control(P>0.05),while the mRNA expression level of the p.Y356X mutant significantly decreased(P<0.05).The PAH protein expression levels of all three mutants were significantly reduced compared to the wild-type control(P<0.05).The extracellular concentration of PAH protein was reduced in the p.R241C and p.Y356X mutants compared to the wild-type control(P<0.05),while there was no significant difference between the p.R243Q mutant and the wild type control(P>0.05).Conclusions p.R243Q,p.R241C and p.Y356X mutants lead to reduced expression levels of PAH protein in eukaryotic cells,with p.R241C and p.Y356X mutants also affecting the function of PAH protein.These three PAH mutants are to be pathogenic.[Chinese Journal of Contemporary Pediatrics,2024,26(2):188-193]

Objective To evaluate the effect of delayed cleaning on the cleaning and disinfection quality of gastro-scopes after pre-treatment with different solutions.Methods According to the factorial design table,combination of the pre-treatment cleaning solutions(factor A)(including multi-enzyme cleaning solution[A1],clean water[A2])and delayed cleaning durations(factor B)(including 0 minutes after pre-treatment[B1],30 minutes after pre-treat-ment[B2],1 hour after pre-treatment[B3],and 3 hours after pre-treatment[B4])yielded eight groups(A1B1,A1B2,A1B3,A1B4,A2B1,A2B2,A2B3,A2B4).According to the usage order of gastroscopes,96 gastroscopes used in the digestive endoscopy center of a tertiary first-class hospital from May to September,2023 were randomly assigned to each group by random number table method,with 12 gastroscopes in each group.Specimens were taken at four time points:after pre-treatment,before cleaning,after cleaning,and after disinfection.Due to instant clea-ning,no specimen before cleaning were taken from A1B1 and A2B1 groups,thus only 3 specimens were taken from these two groups each.Four specimens were taken from gastroscopes in the rest groups,resulting in 360 specimens in total.The internal condition of the biopsy cavity was observed through a cavity detector during each delayed cleaning period after pre-treatment,and specimens were taken at the subsequent reprocessing processes of the gas-troscopes.The microbial conditions of the gastroscopes after pre-treatment,before cleaning,after cleaning,and af-ter disinfection were compared.Results After pre-treatment with multi-enzyme cleaning solution and clean water,there was no statistically significant difference in microbiological detection result(P＞0.05).The biopsy cavity re-mained moist during the delayed cleaning period.There was no statistically significant difference in the microbial de-tection results of factors A and B before and after delayed cleaning as well as after disinfection(all P＞0.05).There was no interaction effect between factor A and B.The distribution of bacterial colonies and disinfection qualified rate of gastroscopes after pre-treatment with two cleaning solutions were also not statistically different(both P＞0.05).Conclusion Delayed cleaning for 30 minutes,1 hour,and 3 hours after pre-treatment does not affect the cleaning and disinfection quality of gastroscopes.When clinical demand is urgent,immediate cleaning should be carried out.However,a certain buffering time(no longer than 3 hours)before cleaning is acceptable,when cleaning and disin-fection workload is heavy and timely cleaning cannot be carried out.

Objective:To investigate the effect of genetic polymorphism of MTHFR C677T (rs1801133) on methotrexate (MTX) related toxicity in pediatric mature B-cell lymphoma patients. Methods:Fifty-eight intermediate and high risk patients under 18 years of age with mature B-cell lymphoma who received 5 g/m2 MTX (24 h intravenous infusion) in Sun Yat-sen University Cancer Center from August 2014 to December 2021 were included,and their toxicity of high-dose MTX (HD-MTX) were monitored and analyzed. Results:Among the 58 pediatric patients,the number of CC,CT,and TT genotypes for MTHFR C677T was 33,19 and 6,respectively. A total of 101 courses of HD-MTX therapy were counted,of which plasma MTX level>0.2 μmol/L at 48 h post-MTX infusion were observed in 35 courses,≤0.2 μmol/L in 66 courses. Inter-group comparison showed that plasma MTX level>0.2 μmol/L at 48 h post-MTX infusion increased the risk of developing oral mucositis (P<0.05). Compared with wild-type (CC genotype),patients in the mutant group (CT+TT genotype) were more likely to develop myelosuppression,manifested as anemia,leucopenia,neutropenia and thrombocytopenia. However,plasma MTX level at 48 h was not associated with MTHFR C677T gene polymorphism. Conclusion:The risk of developing oral mucositis in children with mature B-cell lymphoma is associated with plasma MTX concentration. Polymorphism of MTHFR C677T gene is not related to plasma MTX concentration in children with mature B-cell lymphoma,but is related to grade Ⅲ to Ⅳ hematological toxicity.

Objective:To study the molecular mechanism of functional defect of protein C (PC) caused by point mutations of human protein C gene (PROC) N355S,G392E and T314A. Methods:The wild-type and mutant plasmids (PCWT,PCN355S,PCG392E,PCT314A) of PROC gene were constructed and transiently transfected into HEK293 cells. The expression of mutant proteins in vitro were tested. The mRNA level changes of wild-type and mutant PC after 24 h of transfection were detected by real-time PCR. Western blot and ELISA were used to detect the changes of intracellular and extracellular protein levels of wild-type and mutant PC. The supernatant of cells transfected for 24-48 h was concentrated by ultrafiltration. The protein in the concentrated solution was quantified,and PC activation and enzyme kinetics tests were performed. Clustal Omega multiple sequence alignment was used to analyze the conservation of amino acid mutation sites. The effect of mutation on PC protein structure was analyzed by PyMOL software. Results:The relative expression abundances of PROC mRNA in PCN355S,PCG392E and PCT314A groups were 1.14±0.46,0.96±0.08 and 1.08±0.17,respectively,and there were no significant differences compared with 1.02±0.24 in PCWT group (P>0.05). Western blot analysis of the lysates of transfected cells showed that the content of PCT314A recombinant protein slightly decreased and the band became relatively lighter. The ELISA results of the concentrated cell culture supernatants showed that the PC:Ag levels of PCN355S and PCG392E were 98.8％±2.4％ and 101.4％±3.1％,respectively,with no significant differences compared with PCWT,while PCT314A decreased compared with PCWT (PC:Ag:88.6％±3.2％) (P<0.05). The results of enzyme kinetics test showed that APCN355S (Km=338.3±43.2,Vmax=2.015±0.12),APCG392E (Km=292.2±28.4,Vmax=1.893±0.07) and APCT314A (Km=299.5±24.6,Vmax=1.775±0.06) showed an increase in Km and a decrease in Vmax compared with APCWT (Km=238.2±4.58,Vmax=3.205±0.06). Multiple sequence alignment suggested that the three mutations be highly conservative in different species. The structural model suggested that the amino acid substitutions of N355S,G392E and T314A mutations collide with the surrounding amino acid groups,causing distortion of the surrounding structure,which may have adverse effects on the folding and biological function of PC. Conclusion:The N355S,G392E and T314A mutations in the PROC gene cause functional defects in PC by weakening the binding between PC and substrate. These three mutations have caused serious spatial collisions in the protein structure,affecting the folding of PC and the reactivity of active sites.