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.

Background As one of the key populations in the prevention and treatment of iodine deficiency disorders, it is important to continuously monitor the iodine nutritional level of school-age children. The current reference interval for thyroid volume in China is based on age only, without taking into account differences in individual developmental levels, and the distribution of thyroid volume may vary regionally due to economic, demographic, and environmental factors. The current reference cut-off points for thyroid volume proposed by the World Health Organization are not based on the Chinese population. Objective To understand the iodine nutritional status and distribution of thyroid volume (Tvol) among children aged 8-10 years in Huangpu District, Shanghai, China, to identify impact factors of Tvol, and to propose a reference range upper limit for local thyroid health surveillance, so as to provide a basis for goiter control and prevention. Methods Six hundred children aged 8-10 years in Huangpu District were recruited in 2017, 2020, and 2023, and body height, weight, thyroid volume, urinary iodine, and iodine content of household edible salt were determined. A multilevel model was constructed using population density and area as regional variables, and age, body surface area (BSA), and body mass index (BMI) as potential impact factors for at the individual level, to assess their effects on thyroid volume. Quantile regression of thyroid volume was performed, and the 98th percentile (P₉₈) of thyroid volume was predicted based on age and BSA. Results The iodized salt coverage in the households of surveyed children in 2017, 2020, and 2023 was 72.0%, 57.0%, and 48.0%, respectively, and the iodized salt coverage decreased by year (χ²=24.31, P<0.001). The urinary iodine level of children in 2017 was higher than that in 2020 and 2023 (χ²=18.77, P<0.001). The Tvol medians of children in 2017, 2020, and 2023 were 2.29, 2.49, and 2.97 mL, respectively, and the Tvol increased by year (χ²=60.04, P<0.001). The proportion of goiter was higher in children in 2023 than in 2017 and 2020 (χ²=6.57, P<0.05). Sex differences were not statistically significant for urinary iodine levels, thyroid volume, and goiter. The median Tvol was 2.26, 2.58, and 2.76 mL in children of 8, 9, and 10 years old respectively, and the Tvol increased with age (χ²=49.02, P <0.001). Tvol was positively correlated with age, BSA, and BMI with correlation coefficients of 0.2846, 0.3723, and 0.2950, respectively. The final quantile regression model showed that the strongest effect of BSA was associated with the 98th percentile of Tvol. Multilevel models considering population density or area as regional variables failed to achieve convergence. Conclusion To establish the upper limit of the reference interval for thyroid volume of healthy children in Huangpu District, the effects of age and BSA should be considered at the individual level, and the upper limit of the normal interval for goiter screening is suggested to be the 98th percentile value of BSA at the same age. In addition, the adaptability of population density and regional area as indicators of regional aggregation of thyroid volume distribution still needs to be further explored.

Objective To investigate the impact of COVID-19 infection on the early clinical outcomes of patients undergoing valve replacement. Methods Perioperative data of patients who underwent single valve replacement at the Second Affiliated Hospital of Chinese People's Liberation Army Medical University from January to February 2023 were consecutively collected. Based on COVID-19 infection status, patients were divided into a COVID-19 group and a non-COVID-19 group. The perioperative data were compared between the two groups. Results A total of 136 patients were included, comprising 53 males and 83 females, with a mean age of (53.4±10.2) years. There were 32 patients receiving aortic valve replacements, 102 mitral valve replacements, and 2 tricuspid valve replacements. The COVID-19 group comprised 70 patients, and the non-COVID-19 group included 66 patients. No statistical difference was observed in the incidence of postoperative complications between the two groups [9.09% (6/66) vs. 11.43% (8/70), P=0.654]. However, the COVID-19 group had longer postoperative mechanical ventilation duration [1 201.00 (1 003.75, 1 347.75) min vs. 913.50 (465.50, 1 251.00) min, P=0.001] and ICU stay [3 (2, 3) days vs. 2 (2, 3) days, P<0.001] compared to the non-COVID-19 group. Additionally, troponin I [4.76 (2.55, 7.93) ng/mL vs. 2.66 (1.19, 5.65) ng/mL, P=0.001] and brain natriuretic peptide [608.50 (249.75, 1 150.00) pg/mL vs. 192.00 (100.93, 314.75) pg/mL, P<0.001] levels were significantly higher in the COVID-19 group. Conclusion For patients with single valve disease undergoing elective surgery, short-term outcomes after recovery from COVID-19 infection are favorable, with no significant increase in in-hospital mortality or postoperative complication rates.

Aim To explore the effect of Danggui Shaoyao San on edema in rats with nephrotic syndrome and the underlying mechanism.Methods Rats were randomly divided into control group,model group,Danggui Shaoyao San group(17.2 g·kg-1·d-1),losartan group(30 mg·kg-1·d-1)and tolvaptan group(3 mg·kg-1·d-1).The rat model of nephrot-ic syndrome was established by tail vein injection of adriamycin.After four weeks of treatment,the levels of renal function and 24 h urinary protein were detected.The distribution of aquaporin 2(AQP2)and pS256-AQP2 in renal tissue was detected by immunohisto-chemistry.The levels of plasma arginine vasopressin(AVP)and angiotensin Ⅱ(Ang Ⅱ)were measured by radioimmunoassay.The expressions of renal AQP2,pS256-AQP2,angiotensin type 1 receptor(AT1R),arginine vasopressin receptor 2(V2R)protein and mRNA were measured by Western blot and RT-PCR,respectively.Results The three drugs could improve renal function,reduce proteinuria,decrease plasma AVP and Ang Ⅱ levels,and down-regulate AQP2 and pS256-AQP2 protein and mRNA expression in model rats.Danggui Shaoyao San and tolvaptan were more ef-fective than losartan in reducing plasma AVP levels.Conclusions Danggui Shaoyao San may regulate the expression of AQP2 by reducing the levels of AVP and Ang Ⅱ,and improve the edema of nephrotic syndrome rats.

Aim To study the regulatory effect of poly-datin on D-galactose-induced aging model mice.Methods Fifty-six ICR mice(half male and half fe-male)were divided into normal group,model group,positive group,low,medium and high polydatin treat-ment groups.Aging model was established by subcuta-neous injection of D-galactose(500 mg·kg-1)into the back of neck every day.During the modeling peri-od,the positive group was given donepezil hydrochlo-ride tablets(0.75 mg·kg-1)by gavage,the treat-ment group was given polydatin(40,70,100 mg·kg1)by gavage,and the normal group was given the same amount of normal saline.The learning and cogni-tive ability of mice was evaluated by nesting experi-ment,new object recognition experiment and Morris water maze experiment.The heart,liver,spleen,kid-ney and thymus of mice were taken to calculate the or-gan index.The pathological changes of whole brain tis-sue in mice were observed by hematoxylin-eosin(HE)staining.The levels of T-SOD,MDA,GSH-Px and AchE in serum and whole brain tissue of mice were de-tected by ELISA.The protein expression levels of Keap1,Nrf2 and HO-1 in hippocampus of mice were detected by Western blot.Results Compared with the model group,the nesting ability,the ability to recog-nize new objects and the ability to find platforms under-water of the mice in the positive group and the low,medium and high dose groups of polydatin were im-proved.The organ index increased.The neuronal dam-age in the cerebral cortex and hippocampus was signifi-cantly ameliorated.The activities of T-SOD and GSH-Px in serum and brain tissue increased and the activi-ties of MDA and AchE decreased.The expression lev-els of Nrf2 and HO-1 protein in hippocampus in-creased,and the expression level of Keap1 protein de-creased.Conclusions Polydatin can ameliorate the learning and cognitive impairment in D-galactose-in-duced aging model mice,and its mechanism may be related to the Keap1/Nrf2/HO-1 pathway.

Aim To investigate the protective effect of total flavonoids of Dracocephalum moldavica(TFDM)on atherosclerosis in rats and the inflammation of mouse macrophage RAW264.7 aggravated by trimeth-ylamine N-oxide(TMAO)and its possible mecha-nism.Methods The AS model of SD rats was estab-lished by high-fat diet feeding combined with intraper-itoneal injection of vitamin D3.The rats were divided into control group,model group,simvastatin group(15 mg·kg-1)and TFDM group(60,30,15 mg·kg-1).Biochemical method was used to detect the levels of se-rum total cholesterol(TC),triglyceride(TG)and low density lipoprotein cholesterol(LDL-C).HE staining was used to detect the pathological changes of aortic tissue.ELISA kit was used to detect the expression of TMAO,IL-1β,IL-6 in serum and TNF-α in liver tis-sue.Western blot was used to detect the expression of JAK,STAT and TNF-α protein in aorta.In addition,RAW264.7 macrophages were cultured in vitro,and LPS+TMAO was used to establish a macrophage in-flammation model,which was intervened by TFDM(100,50,25 mg·L-1).CCK-8 was used to determine cell viability and proliferation,and RT-qPCR was used to detect the expression of TNF-α,IL-6,JAK and STAT mRNA in cells.Results TFDM could significantly down-regulate the levels of serum TC,TG,LDL-C,ser-um TMAO,IL-1β,IL-6 and liver TNF-α,reduce aortic plaque deposition,and down-regulate the protein ex-pression of TNF-α,JAK and STAT in aorta.In addi-tion,TFDM intervention can significantly down-regulate the expression of TNF-α,IL-6,JAK,STAT mRNA and the expression of JAK,STAT protein.Conclusion TFDM can reduce the content of TMAO in serum,in-hibit JAK/STAT inflammatory signaling pathway and slow down the occurrence of inflammation,playing an anti-AS role.

In recent decades,the prevalence of diabetes has been increasing year by year,and a series of complications caused by diabetes include diabetic cardiomyopathy,retinopathy,nephropa-thy,osteoporosis and neuropathy.The pathogenesis of these com-plications is still very unclear,and there is an urgent need for some therapeutic drugs to meet the clinical needs.In this re-view,we summarize the pathogenesis of various diabetic compli-cations in the past five years,the markers that have received more attention and the main therapeutic drugs,in order to pro-vide references for the drug research and development of diabetic complications.

Mitral valve prolapse is one of the common causes of mitral regurgitation.Mitral valve prolapse complicated with leaflet cleft is rare in clinical practice,which most often undergo surgical mitral valve repair or mitral valve replacement.We report a case of mitral valve prolapse with posterior leaflet cleft treated by transcatheter edge-to-edge mitral valve repair,in order to provide a model for similar cases.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective:To observe the clinical efficacy and safety of hypomethylating agent therapy in chronic myelomonocytic leukemia(CMML).Methods:From February 2014 to June 2021,the clinical data,efficacy,survival time and safety of CMML patients diagnosed in the Second Hospital of Hebei Medical University and treated with hypomethylating agent therapy were retrospectively analyzed.Results:A total of 25 CMML patients received hypomethylating agent therapy,including 18 cases treated with decitabine(DEC)and 7 cases treated with azacytidine(AZA)as the basic treatment.Among them,20 patients responded,and 7 patients got complete remission(CR).All patients with CR were treated with DEC as the basic treatment.Five cases of CR occurred in the first 4 courses of treatment.After a median follow-up of 16.4(9.4-20.5)months,4 patients with CR progressed to acute myeloid leukemia(AML).The median overall survival(OS)time of 25 CMML patients was 17.4 months(95％CI:12.437-22.363).According to MD Anderson prognostic scoring system(MDAPS),CMML-specific prognostic scoring system(CPSS),CPSS molecular(CPSS-mol),Mayo molecular model(MMM),risk stratification of patients was performed,and the difference only between different risk stratification of MDAPS and survival time was statistically significant.Common adverse reactions of hypomethylating agent therapy in CMML patients included infection,gastrointestinal reaction,hematological toxicity,skin allergy and liver function damage.All patients'symptoms were improved after corresponding treatment.Conclusion:Hypomethylating agent therapy is effective and safe for CMML patients.CR mostly occurs in the first 4 courses of treatment,and hypomethylating agent therapy combined with low-dose chemotherapy can be used for patients who do not respond.Hypomethylating agent therapy can delay the disease,but can't prevent progression.