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.

ObjectiveThis study aimed to investigate the effects of 4-week high-intensity interval training (HIIT) on synaptic plasticity in the prefrontal cortex (PFC) of rats exposed to chronic unpredictable mild stress (CUMS), and to explore its potential mechanisms. MethodsA total of 48 male Sprague-Dawley rats were randomly divided into 4 groups: control (C), model (M), control plus HIIT (HC), and model plus HIIT (HM). Rats in groups M and HM underwent 8 weeks of CUMS to establish depression-like behaviors, while groups HC and HM received HIIT intervention beginning from the 5th week for 4 consecutive weeks. The HIIT protocol consisted of repeated intervals of 3 min at high speed (85%-90% maximal training speed, S_max) alternated with one minute at low speed (50%-55% S_max), with 3 to 5 sets per session, conducted 5 d per week. Behavioral assessments and tail-vein blood lactate levels were measured at the end of the 4th and 8th weeks. After the intervention, rat PFC tissues were collected for Golgi staining to analyze synaptic morphology. Enzyme-linked immunosorbent assays (ELISA) were employed to detect brain-derived neurotrophic factor (BDNF), monocarboxylate transporter 1 (MCT1), lactate, and glutamate levels in the PFC, as well as serotonin (5-HT) levels in serum. Additionally, Western blot analysis was conducted to quantify the expression of synaptic plasticity-related proteins, including c-Fos, activity-regulated cytoskeleton-associated protein (Arc), and N-methyl-D-aspartate receptor 1 (NMDAR1). ResultsCompared to the control group (C), the CUMS-exposed rats (group M) exhibited significant reductions in sucrose preference rates, number of grid crossings, frequency of upright postures, and entries into and duration spent in open arms of the elevated plus maze, indicating marked depressive-like behaviors. Additionally, the group M showed significantly reduced dendritic spine density in the PFC, along with elevated levels of c-Fos, Arc, NMDAR1 protein expression, and increased concentrations of lactate and glutamate. Conversely, BDNF and MCT1 contents in the PFC and 5-HT levels in serum were significantly decreased. Following HIIT intervention, rats in the group HM displayed considerable improvement in behavioral indicators compared with the group M, accompanied by significant elevations in PFC MCT1 and lactate concentrations. Furthermore, HIIT notably normalized the expression levels of c-Fos, Arc, NMDAR1, as well as glutamate and BDNF contents in the PFC. Synaptic spine density also exhibited significant recovery. ConclusionFour weeks of HIIT intervention may alleviate depressive-like behaviors in CUMS rats by increasing lactate levels and reducing glutamate concentration in the PFC, thereby downregulating the overexpression of NMDAR, attenuating excitotoxicity, and enhancing synaptic plasticity.

Eighteen compounds were isolated from the methanol extract of the fruits of Litsea cubeba by silica gel, ODS, Sephadex LH-20 column chromatography, semi-preparative RP-HPLC, chiral HPLC and recrystallization. Their structures were elucidated by spectroscopic analyses and by comparison with reported spectroscopic data and physicochemical properties, and the absolute configurations of the enantiomers were established by experimental and calculated electronic circular dichroism spectra. These compounds were identified as (+)-(R)-4-hydroxypiperitenone (1a), (-)-(S)-4-hydroxypiperitenone (1b), (3S,4S,6R)-3,6-dihydroxy-1-menthene (2), (4S,5R)-4-hydroxy-5-isopropyl-2-methylcyclohex-2-en-1-one (3), (R)-6-hydroxy-3-(2-hydroxypropan-2-yl)-6-methylcyclohex-2-enone (4), (4S,6R)-4-hydroxy-6-isopropyl-3-methylcyclohex-2-enone (5), (1R,3S,4R)-3-hydroxy isopulegol (6), subamone (7), (6S)-3,7-dimethyl-7-hydroxy-2(Z)-octen-6-olide (8), (6S)-6,7-dihydroxy-3,7-dimethyloct-2(Z)-enoate (9), holostylactone (10), sesamin (11), dimethylmatairesinol (12), p-hydroxybenzoylcarbinol (13), syringaldehyde (14), p-hydroxybenzaldehyde (15), 4-hydroxy-3-methoxybenzaldehyde (16), 5,4ʹ-dihydroxy-7-methoxyflavone (17). Among them, compounds 1a and 1b were a pair of new monoterpenoid enantiomers, 8 and 9 were new natural products, 2-7, 10, 11 and 17 were isolated from Litsea genus for the first time. The in vitro anti-inflammatory effects of compounds 1-17 were evaluated using lipopolysaccharide-stimulated RAW264.7 cells, the results showed that compound 14 exhibited significant anti-inflammatory activity with NO inhibitory rate of 66.27% at a concentration of 40 μmol·L^-1.

Objective:To understand the whole genome and genetic evolution characteristics of the first epidemic influenza A (H3N2) viruses in Wuxi from 2022-2023.Methods:Real time fluorescence quantitative RT-PCR method was used to perform typing on respiratory samples of influenza cases. Virus isolation was performed on samples with positive nucleic acid of subtype A H3N2 influenza virus detected. After cell culture, nucleic acid was extracted from strains with red blood cell agglutination test (HA) ≥ 1∶8, whole genome sequence was amplified, library was constructed, and computer sequencing was performed using MiSeq sequencer. Using NC_007366.1 as reference strain, the data were analyzed using CLC Genomics Workbench (Version 23) software. The phylogenetic tree was constructed using MEGA 7.0 software, and the N-glycosylation sites were predicted by NetNGlyc 1.0 Server software.Results:The nucleotide homology and amino acid homology among 35 strains of influenza A H3N2 virus from 2022 to 2023 were 96.4%-100% and 95.2%-100%, respectively. The 16 epidemic strains in 2022 belong to the 3C.2a1b.2a.1a evolutionary branch, while the 19 epidemic strains in 2023 belong to the 3C.2a1b.2a.2a.3a.1 evolutionary branch. There are 7 differences in the nucleotide sequence of the HA gene between the 2022 epidemic strain and the corresponding vaccine strain, sharing 15 mutation sites; There are 28 differences in the nucleotide sequence of the HA gene between the 2023 epidemic strain and the corresponding vaccine strain, sharing 17 mutation sites. The HA genes of 35 epidemic strains all lack N-glycosylation site 61: NSS, while in 2023, the HA genes of 19 epidemic strains added N-glycosylation site 110: NSS.Conclusions:The HA and NA genes of influenza A H3N2 virus in 2022 and 2023 belong to two evolutionary branches, respectively, and both show specific amino acid site changes compared to the corresponding vaccine strains. The antigen matching between the 2022 epidemic strain and the vaccine strain is relatively good, while there is a risk of low antigen matching between the 2023 epidemic strain and the vaccine strain.

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 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 evaluate the efficacy of modified femoral neck osteotomy(mFNO)in the surgical treatment of patients with ankylosing spondylitis(AS)and severe spinal kyphosis combined with hip flexion contracture.Methods:A retrospective analysis was conducted on 61 AS patients(103 hips)with spinal kyphosis and hip flexion contracture who underwent pedicle subtraction osteotomy(PSO)and total hip arthroplasty(THA)from January 1,2019 to November 15,2023.Data on mFNO operation time,blood loss,preoperative and postoperative values of the angle of the trunk and lower limb(ATL),hip passive range of motion(ROM),visual analogue scale(VAS),and incidence of in-hospital compli-cations were recorded.Statistical analysis was performed using paired-samples t test.P＜0.05 was con-sidered statistically significant.Results:The study ultimately included 10 cases,9 males and 1 female,with an average age of(41.30±9.03)years.These patients underwent surgery for a total of 52 times,including 19 hips both receiving mFNO and THA,and 14 times PSO.The average operation time for nine bilateral mFNO was(133.11±34.81)min,with blood loss of(433.33±187.10)mL.A unilateral mFNO took 60 min with 200 mL of blood loss.The preoperative ATL of 19 hips was 40.37°±13.66°,and the postoperative ATL value was 88.47°±12.46°(P＜0.05).The preoperative VAS score was 0,while the postoperative VAS score was 5.95±1.51(P＜0.05).The preoperative hip extension ROM was 37.37°±18.13°,while the postoperative hip extension ROM was-4.95°±21.24°(P＜0.05).Hip flexion ROM improved from 37.37°±18.13° to 50.79°±20.36° after FNO(P＜0.05).There were three cases of in-hospital complications(3/52,5.67％):One case of postoperative atelectasis fol-lowing PSO(1/52,1.92％),one greater trochanter fracture identified during THA(1/52,1.92％),and one early dislocation post-THA(1/52,1.92％).Conclusion:mFNO significantly improves the ATL in AS patients with severe spinal kyphosis combined with hip flexion contracture,facilitating PSO and THA surgeries.

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 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 investigate the neuroprotective effect and potential mechanism of rehabilitation training combined with citicoline on cerebral hemorrhage model in mice based on Keap1/Nrf2/ARE signaling pathway.Methods The C57BL/6 male mice were randomly divided into sham operation group(sham operation treatment),model group(right caudate putamen hemorrhage model induced by type Ⅶcollagenase),choline group(model+choline 64 mg·kg-1),rehabilitation training group(rehabilitation training)and combined group(model+rehabilitation training+choline 64 mg·kg-1).The study observed the modified neurological severity score(mNSS)in mice with cerebral hemorrhage;colorimetric assays were used to detect the expression of malondialdehyde(MDA),superoxide dismutase(SOD)and catalase(CAT)in brain tissues;protein imprinting and reverse transcription-quantitative polymerase chain reaction were employed to assess the expression of Kelch-like ECH-associated protein 1(Keap1),nuclear factor erythroid 2-related factor 2(Nrf2)/antioxidant response element(ARE),heme oxygenase-1(HO-1),quinone oxidoreductase 1(NQ01)proteins and mRNA in brain tissues.Results The mNSS scores of sham operation group,model group,citicoline group,rehabilitation training group and combined group were 0,1.56±0.73,1.00±0.00,0.78±0.44 and 0.67±0.50;the MDA contents were(6.93±0.92),(22.97±0.77),(19.26±1.73),(13.21±0.78)and(7.25±0.97)nmol·mgprot-1;the relative expression of Keap1 protein were 0.79±0.03,1.02±0.04,0.95±0.10,0.90±0.09 and 0.86±0.05;the relative expression levels of Nrf2 protein were 0.94±0.12,0.71±0.08,0.90±0.07,0.98±0.12 and 1.33±0.25.There were significant differences in the above indexes between the model group and the sham operation group(P＜0.05,P＜0.01);there were significant differences between the citicoline group and the rehabilitation training group,the model group(P＜0.05,P＜0.01);there were significant differences between the combined group and the citicoline group,the rehabilitation training group except for protein expression of Keap1(all P＜0.01).Conclusion Rehabilitation training and citicoline can reduce the symptoms of neurological deficits in mice with cerebral hemorrhage.The mechanism way be that they can activate the Keap1/Nrf2/ARE signaling pathway to exert anti-oxidative stress,and the combined effect is the best.