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 establish a general method for the simultaneous determination of hydroxyphenyl esters and quaternary ammonium bacteriostatic agents in eye drops.Methods:The chromatographic analysis was per-formed on an Agilent C18 column(4.6 mm ×250 mm,5 μm)with 1％triethylamine solution(pH adjusted to 5.0 with phosphoric acid)as mobile phase A and methanol as mobile phase B.Gradient elution was performed at col-umn temperature of 40 ℃.The detection wavelength was 214 nm,the flow rate was 1 mL·min-1,and the injec-tion volume was 20 μL.Results:Methylparaben,ethylparaben,propylparaben,butylparaben,benzalkonium chlo-ride and benzalkonium bromide were 0.11-559.0,0.10-513.0,0.10-258.8,0.11-270.5,1.07-537.0 and 1.03-512.8 μg·mL-1,respectively.The linear range was good(r＞0.999).The average recoveries of meth-ylparaben,benzalkonium bromide and benzalkonium chloride were 104.7％(RSD=1.3％),102.6％(RSD=1.1％)and 100.9％(RSD=1.1％),respectively.The contents of bacteriostatic agent in 100 batches of eye drops from 36 varieties of 12 enterprises were determined,and the accurate results were obtained.Conclusion:This meth-od provides a reference for the content quality control and safety evaluation of bacteriostatic agents in eye drops.

Objective To explore the clinical efficacy of double beam double tunnel enhanced reconstruction technique in the treatment of knee anterior cruciate ligament(ACL)training injuries.Methods Twenty-nine cases of ACL injury of knee joint from January 2021 to December 2021 were retrospectively analyzed.All the cases were underwent ligament reconstruc-tion surgery.Cases were grouped by surgical technique:there were 14 patients in conventional reconstruction group,including 13 males and 1 female,aged from 22 to 31 years old with an average of(27.07±7.28)years old,autogenous hamstring tendon was used for ligament reconstruction.There were 15 patients in the enhanced reconstruction group,including 13 males and 2 females,aged from 25 to 34 years old with an average of(29.06±4.23)years old,double tunnel ligament reconstruction,the autogenous hamstring muscle was used as the anteromedial bundle,and the posterolateral bundle was replaced by a high-strength line.The difference between knee tibial anterior distance,Lysholm score,International Knee Literature Committee(IKDC)subjective score,Tegner motor level score and visual analog scale(VAS)at 6th and 12th months after the surgery,limb symmetry index(LSI)were recorded at the last follow-up and surgery-related adverse effects during follow-up.Results All patients were followed up,ranged from 13 to 15 months with an average of(13.7±0.8)months.There were no serious adverse reactions related to surgery during the period.There was no statistical difference between the preoperative general data and the observation index of the two groups(P＞0.05).The difference in tibial anterior distance at 6 and 12 months in the enhanced re-construction group(1.45±0.62)mm and(1.74±0.78)mm which were lower those that in the conventional reconstruction group(2.42±0.60)mm and(2.51±0.63)mm(P＜0.05).There was no significant difference in postoperative Lysholm score,Tegner motor level score,IKDC score,VAS,and limb symmetry index at the last follow-up(P＞0.05).Conclusion The enhanced recon-struction technique can more effectively maintain the stability of the knee joint and has no significant effect on the postoperative knee joint function compared with the traditional ligament reconstruction technique.The short-term curative effect is satisfac-tory,and it is suitable for the group with high sports demand.

Objective To explore the effectiveness and safety of percutaneous coronary artery shock wave balloon angioplasty(IVL)under the guidance of intravascular ultrasound(IVUS)for the treatment of severe calcification lesions in the left main artery(LM).Methods A total of 26 patients with severe LM(mouth,body,bifurcation)calcification admitted to Jiangnan University Affiliated Hospital from October 2022 to April 2024 were included,with an average age of 72.0(61.8,75.4)years.Under the guidance of IVUS,IVL was used for pre-treatment of calcified lesions,followed by percutaneous coronary intervention(PCI)with stent/drug balloon implantation.All patients were evaluated using IVUS before and after the use of IVL and after PCI.And compare the IVUS intracavity related data before and after treatment[plaque burden(PB)、minimum lumen area(MLA)、minimum lumen diameter(MLD)]and calcification fracture number,minimum stent area(MSA),stent expansion coefficient(expansion,EXP),etc.Results There were 26 patients(2 with opening lesions,7 with body lesions,and 17 with bifurcation lesions at the end of the main trunk),including 7 with stable angina pectoris(SAP),10 with unstable angina(UA),4 with acute ST-segment elevation myocardial infarction(STEMI),and 5 with non ST-segment elevation myocardial infarction(NSTEMI).The PB at the most severe site of calcification decreased by 79.50(76.00,83.75)％compared to 80.00(76.00,83.75)％after IVL(P=0.001),MLA increased by 3.39(3.14,3.68)mm2 compared to 3.38(3.14,3.67)mm2 after IVL(P=0.039),MLD increased by 3.21(3.07,3.30)mm compared to 3.20(3.07,3.30)mm after IVL(P=0.024),and there was 100％calcification rupture(1/2 cases,2/9 cases,≥3/15 cases).The stent/drug ball was successfully implanted 100％,with EXP of(89.15±4.42)％and an MSA of 7.20(6.46,7.45)mm2.No adverse events such as death,angina or recurrent myocardial infarction occurred during the 3 months follow-up after surgery.Conclusions After evaluation by IVUS and pre-treatment with IVL,PCI was successfully completed for severe calcification lesions in LM,and IVL can be used as an option for the treatment of severe calcification in LM.

Objective:To investigate the neuroprotective effect of hesperidin combined with enriched environment on ferroptosis in collagenase-induced intracerebral hemorrhage(ICH) mouse model as well as the ferroptosis mechanism.Methods:ICH model was established by injecting collagenase Ⅶ into caudate putamen nucleus. Ninty C57BL/6J mice were randomly divided into 6 groups according to a random number table: sham group, intracerebral hemorrhage group, enriched environment group, hesperidin group, enriched environment and hesperidin group (combination group), and combination group + Nrf2 specific inhibitor ML385 (inhibitor group), with 15 mice in each group. The mice in inhibitor group, intracerebral hemorrhage group, enriched environment group, hesperidin group and combination group were injected with 0.5 μL collagenase type Ⅶ solution (0.075 U/μL, dissolved with 0.9% NaCl solutin) for ICH modeling, and the mice in sham group were injected with 0.9% normal saline. The hesperidin group, combination group, and inhibitor group were given hesperidin solution (dissolved in 0.5% carboxymethyl cellulose sodium) by gavage within 6 hours after the modeling surgery. The sham group, intracerebral hemorrhage group, and enriched environment group were given equal volumes of 0.5% carboxymethyl cellulose sodium solution by gavage. The inhibitor group was intraperitoneally injected with Nrf2 specific inhibitor ML385 (30 mg/kg, dissolved in 5% DMSO), while the other groups were intraperitoneally injected with an equal volume of 5% DMSO. Both gastric perfusion and intraperitoneal injection were completed within 6 hours after the end of modeling operation, once a day for 14 days. After the postoperative recovery of the mice, the enriched environment group, combination group, and inhibitor group were placed in enriched environment cages, while the sham group, intracerebral hemorrhage group, and hesperidin group were placed in regular cages. After all intervention were completed, all mice were evaluated using the modified neurological severity score (mNSS). Then the mice were subjected to brain water content detection, Prussian blue staining, ELISA detection of changes in malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione peroxidase 4 (Gpx4), PCR and Western blot detection of nuclear factor E2 related factor 2 (Nrf2) and Gpx4 at the mRNA level and protein level. The GraphPad Prism 9 software was used for statistical analysis. ANOVA was used for multi-group comparison, and Tukey test was used for multiple comparisons.Results:(1) There was a statistically significant difference in mNSS scores among the 6 groups ( F=66.35, P<0.001). The mNSS score of the intracerebral hemorrhage group(8.00±1.46) was higher than that of the sham group(0.86±0.83)( P<0.05). The mNSS scores of the enriched environment group (6.47±1.13) and hesperidin group (6.13±1.25) were lower than that of the intracerebral hemorrhage group, but higher than that of the combination group (4.53±1.30)(all P<0.05). (2) There was a statistically significant difference in the percentage of brain water content among the 6 groups ( F=33.29, P<0.001). The percentage of brain water content in the intracerebral hemorrhage group was higher than that in the sham group.The percentage of brain water content in the enriched environment group and hesperidin group were lower than that in the intracerebral hemorrhage group, but higher than that in the combination group (all P<0.05). (3) The result of Prussian blue staining showed that iron deposition in the intracerebral hemorrhage group was higher than that in the sham group, while the iron depositions in the enriched environment group and hesperidin groups were lower than that in the intracerebral hemorrhage group, but higher than that in the combination group(all P<0.05). (4) There were statistically significant differences in the expression levels of Nrf2 and Gpx4 mRNA and protein among the 6 groups ( F=27.73, 31.24, 26.79, 13.79, all P<0.001). The mRNA and protein levels of Nrf2 and Gpx4 in the combination group were higher than those in the enriched environment group, hesperidin group, but higher than those in the inhibitor group(all P<0.05). (5) The results of ELISA showed that the levels of MDA, Gpx4, ROS, and SOD in the brain tissues of 6 groups were statistically significant ( F=111.20, 21.53, 29.45, 22.75, all P<0.001). Among them, the MDA and ROS in the combination group ((14.05±0.57) nmol/mL, (75.46±3.40) ng/mL) were lower than those in the enriched environment group ((18.17±2.51) nmol/mL, (97.23±3.43) ng/mL), hesperidin group ((17.24±0.68) nmol/mL, (90.02±9.46) ng/mL) and the inhibitor group ((17.08±0.64) nmol/mL, (101.07±3.38) ng/mL), while Gpx4 and SOD ((340.40±31.21) pg/mL, (62.55±2.81) ng/mL) were higher than those in the enriched environment group ((267.81±27.17) pg/mL, (50.47±8.38) ng/mL), hesperidin group ((271.55±34.36) pg/mL, (50.55±8.19) ng/mL) and the inhibitor group ((235.65±72.54)pg/mL, (52.67±3.56)ng/mL)(all P<0.05). Conclusion:Enriched environment and hesperidin can inhibit ferroptosis after ICH by activating the Nrf2/GPX4 pathway, exerting neuroprotective effects on ICH mouse models, and the combined treatment of the enriched environment and hesperidin has a more significant effect.

Objective:To establish a rapid quantitative PCR (qPCR) technique for Mycobacterium marinum skin infections, and to analyze its clinical diagnostic efficiency. Methods:DNA was extracted from Mycobacterium marinum colonies and serially diluted (10 -1 to 10 -8). Twelve pairs of previously reported primers and probes, as well as 6 pairs of newly designed primers and probes in this study, were used for qPCR amplification to identify the most sensitive primers and probes for the detection of Mycobacterium marinum. Skin lesion tissues were collected from 72 patients with confirmed Mycobacterium marinum infections (experimental group) and 68 with other mycobacterial infections (control group) at Shandong Provincial Hospital for Skin Diseases & Shandong Provincial Institute of Dermatology and Venereology, Shandong First Medical University & Shandong Academy of Medical Sciences in 2021. These skin tissues were subjected to qPCR amplification, interferon-gamma release assay (IGRA), acid-fast staining, and tissue culture to evaluate the diagnostic efficacy. Results:The newly designed primers and probes targeting the mycobacterial enhanced infection locus 2 (Mel2) demonstrated the highest sensitivity, with a detection limit of 0.86 copies/μl (cycle threshold value = 37) ; the qPCR amplification with the Mel2 primers/probes did not yield positive results when used for the detection of other mycobacteria (including Mycobacterium leprae and Staphylococcus spp) . Among the 72 patients in the experimental group, 44 were positive for qPCR with a sensitivity of 61.1% (95% CI: 49.6% - 71.5%), and 47 were positive for culture with a sensitivity of 65.2% (95% CI: 53.8% - 75.3%) ; all the 68 controls were negative for both qPCR and culture, with their specificities both being 100%. Among 65 patients subjected to IGRA, 31 were positive with a sensitivity of 47.7% (95% CI: 36.0% - 59.6%), while 16 out of 25 controls were negative for IGRA with a specificity of 64.0% (95% CI: 44.5% - 79.8%). Among 58 patients subjected to acid-fast staining, 37 were positive with a sensitivity of 63.8% (95% CI: 50.9% - 74.9%), and 52 out of 66 controls were negative for acid-fast staining with a specificity of 78.8% (95% CI: 67.5% - 86.9%). The combination of qPCR and culture resulted in a sensitivity of 93% and a specificity of 100% for the detection of Mycobacterium marinum. Conclusion:In this study, a highly sensitive qPCR assay was developed for the detection of Mycobacterium marinum, and its combination with culture could further improve the detection sensitivity.

Objective To design a portable intelligent cleaner for medical lumen instruments to enhance cleaning efficiency.Methods The portable intelligent cleaner had a box-body shape and a shell made of 304 stainless steel,which was composed of a circuit control board,a micro pump,lithium batteries,a charging interface,a rinse tube and connectors.The circuit control board used a STM32G030C8T6 integraged circuit,which was equipped with a countdown digital tube to display the time left for cleaning;the micro pump and lithium batteries were placed at the inner wall of the box bottom,the charging interface and water inlet/outlet inteface were put on the outside of the front wall of the box bottom,the water inlet/outlet interface was connected with a silicon rinse tube linked to an adapter at its distal end,and the adapters with different calibers were compatible with sizes of medical lumen instruments.Totally 9 672 pieces of lumen instruments received by some hospital's disinfection supply center from May to October 2021 were divided into 2 groups with the convenience sampling method,with 4 836 pieces in each group.The odd-numbered instruments were enrolled into a control group and cleaned with an ultrasonic cleaner and a lumen brush,and the even-numbered instruments were included into an experimental group and cleaned conventionally after pretreatment by the intelligent cleaner.The two groups were compared in terms of eaning efficiency and satisfaction.Results Testing by visual inspection,magnifying glass with light source and white stripe method showed that the experimental group behaved better than the control group in the cleaning qualification rate,whose satisfaction rate(100％)was also higher than that of the control group(86.53％),with all the differences being statistically significant(P＜0.05).Conclusion The portable cleaner with easy operation enhances the cleaning quality and efficiency for medical lumen instruments.[Chinese Medical Equipment Journal,2024,45(10):114-117]

Objective:To analyze the clinical characteristics and all-cause mortality influencing factors of patients with Keshan disease.Methods:Clinical data of patients with Keshan disease from Keshan disease areas in Sichuan Province and Yunnan Province were collected and retrospectively analyzed for clinical characteristics and survival status during regular follow-up. According to the survival status of patients, the survey subjects were divided into a survival group and a death group. All-cause mortality (referring to the death caused by various reasons throughout the follow-up period) was used as the study endpoint. Kaplan-Meier (K-M) survival curve analysis and log-rank χ 2 test were performed, univariate and multivariate Cox regression analysis were used for all-cause mortality factor analysis. Results:A total of 176 patients with Keshan disease were collected, including 92 cases in Sichuan Province and 84 cases in Yunnan Province. Among all the patients, there were 105 males, accounting for 59.66%, and 71 females, accounting for 40.34%. The age was (53.89 ± 13.19) years old. Thirty-five cases died from all causes, with a mortality rate of 19.89%. There were significant differences in age ( t = 2.09, P = 0.038), New York Heart Association (NYHA) cardiac function grading (χ 2 = 14.62, P < 0.001) and ventricular premature contraction (χ 2 = 6.82, P = 0.009) between the survival group and the death group. K-M survival curve analysis showed that patients with Keshan disease complicated by premature ventricular contraction and high NYHA cardiac function grading (Ⅲ and Ⅳ) had higher all-cause mortality (log-rank χ 2 = 8.72, 22.49, P < 0.05). Univariate Cox regression analysis showed that NYHA cardiac function grading and ventricular premature contraction ( HR = 3.09, 2.71, P < 0.05) were predictive influencing factors for all-cause mortality in patients with Keshan disease. Multivariate Cox regression analysis showed that NYHA cardiac function grading ( HR = 6.57, P = 0.002) and ventricular premature contraction ( HR = 2.98, P = 0.050) were independent factors for all-cause mortality in patients with Keshan disease. Conclusions:Among 176 patients with Keshan disease, the number of patients with poor cardiac function (NYHA cardiac function grading Ⅲ and Ⅳ) and arrhythmia is high. NYHA cardiac function grading and ventricular premature contractions are independent influencing factors for all-cause mortality in patients with Keshan disease.

Objective To analyze the risk factors and survival status of Epstein-Barr virus(EBV)infection in pa-tients with aplastic anemia(AA)after haploid allogeneic hematopoietic stem cell transplantation(Haplo-HSCT).Methods Clinical data of 78 AA patients who underwent Haplo-HSCT in the hematology department of a hospital from January 1,2019 to October 31,2022 were analyzed retrospectively.The occurrence and onset time of EBV viremia,EBV-related diseases(EBV diseases),and post-transplant lymphoproliferative disorders(PTLD)were ob-served,risk factors and survival status were analyzed.Results Among the 78 patients,38 were males and 40 were females,with a median age of 33(9-56)years old;53 patients experienced EBV reactivation,with a total inci-dence of 67.9％,and the median time for EBV reactivation was 33(13,416)days after transplantation.Among pa-tients with EBV reactivation,49 cases(62.8％)were simple EBV viremia,2 cases(2.6％)were possible EBV di-seases,and 2 cases(2.6％)were already confirmed EBV diseases(PTLD).Univariate analysis showed that age 1＜40 years old at the time of transplantation,umbilical cord blood infusion,occurrence of acute graft-versus-host disease(aGVHD)after transplantation,and concurrent cytomegalovirus(CMV)infection were independent risk fac-tors for EBV reactivation in AA patients after Haplo-HSCT.Multivariate analysis showed that concurrent CMV in-fection was an independent risk factor for EBV reactivation in A A patients after Haplo-HSCT(P=0.048).Ritu-ximab intervention before stem cell reinfusion was a factor affecting the duration of EBV reactivation(P＜0.05).The mortality of EBV viremia,EBV diseases,and PTLD alone were 8.2％,50.0％,and 100％,respectively.The 2-year overall survival rate of patients with and without EBV reactivation were 85.3％,and 90.7％,respectively,difference was not statistically significant(P=0.897).However,patients treated with rituximab had 2-year lower survival rate than those who did not use it,with a statistically significant difference(P=0.046).Conclusion EBV reactivation is one of the serious complications in AA patients after Haplo-HSCT,which affects the prognosis and survival of patients.

Objective To compare the contents of alkaloid in Aconiti Kusnezoffii Radix with different degrees of processing and their effects on electrocardiogram and vagus nerve action potential in SD rats;To establish a toxicity evaluation method for Aconiti Kusnezoffii Radix and its processed products.Methods HPLC was used to determine the contents of six alkaloid components,including benzoyl neoaconitine,benzoyl aconitine,benzoyl subeaconitine,neoaconitine,subeaconitine and aconitine in Aconiti Kusnezoffii Radix and Aconiti Kusnezoffii Radix Cocta of soaking and boiled for 30 minutes,boiled for 4 h without soaking,soaking and boiled for 4 h,and soaking and boiled for 8 h.SD rats were subjected to sublingual drainage with Aconiti Kusnezoffii Radix and four types of processed products.The vagus nerve action potential and electrocardiogram of rats before and after administration were recorded,and the correlation analysis between alkaloid content and vagus nerve action potential and heart rate was conducted.Results The contents of alkaloid of the four processed products showed that the content of diester alkaloids was soaking and boiled for 30 min>boiled for 4 h without soaking>soaking and boiled for 4 h>soaking and boiled for 8 h;monoester alkaloid content:boiled for 4 h without soaking>soaking and boiled for 30 min>soaking and boiled for 4 h>soaking and boiled for 8 h.After the administration of each sample,compared with the basal discharge,the vagus nerve discharge of rats with different processed products was changed by sublingual administration,heart rate increased,the degree of arrhythmia increased,and it varied with the degree of processing;the results of correlation analysis showed that there was a significant correlation between the nerve discharge area and the contents of diester alkaloids and total alkaloids.Conclusion The action potential of the vagus nerve and electrocardiogram of rats after sublingual drainage administration can reflect the degree of numbness in the tongue,which can provide reference for the study of tongue sensation of Aconiti Kusnezoffii Radix.