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.

ObjectiveTo explore the role and potential mechanism of circulating glutamate in enhancing insulin sensitivity by aerobic exercise. This research may provide a novel strategy for preventing metabolic diseases through precise exercise interventions. MethodsTo investigate the effects of elevated circulating glutamate on insulin sensitivity and its potential mechanisms, 18 male C57BL/6 mice aged 6 to 8 weeks were randomly divided into 3 groups: a control group (C), a group receiving 500 mg/kg glutamate supplementation (M), and a group receiving 1 000 mg/kg glutamate supplementation (H). The intervention lasted for 12 weeks, with treatments administered 6 d per week. Following the intervention, an insulin tolerance test (ITT) and a glucose tolerance test (GTT) were conducted. Circulating glutamate levels were measured using a commercial kit, and the activity of the skeletal muscle InsR/IRS1/PI3K/AKT signaling pathway was analyzed via Western blot. To further investigate the role of circulating glutamate in enhancing insulin sensitivity through aerobic exercise, 30 male C57BL/6 mice were randomly assigned to 3 groups: a control group (CS), an exercise intervention group (ES), and an exercise combined with glutamate supplementation group (EG). The ES group underwent treadmill-based aerobic exercise, while the EG group received glutamate supplementation at a dosage of 1 000 mg/kg in addition to aerobic exercise. The intervention lasted for 10 weeks, with sessions occurring 6 d per week, and the same procedures were followed afterward. To further elucidate the mechanism by which glutamate modulates the InsR/IRS1/PI3K/AKT signaling pathway, C2C12 myotubes were initially subjected to graded glutamate treatment (0, 0.5, 1, 3, 5, 10 mmol/L) to determine the optimal concentration for cellular intervention. Subsequently, the cells were divided into 3 groups: a control group (C), a glutamate intervention group (G), and a glutamate combined with MK801 (an NMDA receptor antagonist) intervention group (GK). The G group was treated with 5 mmol/L glutamate, while the GK group received 50 μmol/L MK801 in addition to 5 mmol/L glutamate. After 24 h of intervention, the activity of the InsR/IRS1/PI3K/AKT signaling pathway was analyzed using Western blot. ResultsCompared to the mice in group C, the circulating glutamate levels, the area under curve (AUC) of ITT, and the AUC of GTT in the mice of group H were significantly increased. Additionally, the expression levels of p-InsRβ, IRS1, p-AKT, and p-mTOR proteins in skeletal muscle were significantly downregulated. Compared to the mice in group CS, the circulating glutamate levels, the AUC of ITT, and the AUC of GTT in the mice of group ES were significantly reduced. Additionally, the expression levels of p-InsRβ, IRS1, p-AKT, and p-mTOR proteins in skeletal muscle of group ES mice were significantly upregulated. There were no significant changes observed in the mice of group EG. Compared to the cells in group 0 mmol/L, the expression levels of p-InsRβ, p-IRS1, p-PI3K, and p-AKT proteins in cells of group 5 mmol/L were significantly downregulated. Compared to the cells in group C, the expression levels of p-InsRβ, p-IRS1, p-PI3K, and p-AKT proteins in the cells of group G were significantly downregulated. No significant changes were observed in the cells of group GK. ConclusionLong-term aerobic exercise can improve insulin sensitivity by lowering circulating levels of glutamate. This effect may be associated with the upregulation of the InsR/IRS1/AKT signaling pathway activity in skeletal muscle. Furthermore, glutamate can weaken the activity of the InsR/IRS1/PI3K/AKT signaling pathway in skeletal muscle, potentially by binding to NMDAR expressed in skeletal muscle.

Major depressive disorder(MDD)is a prevalent con-dition associated with substantial impairment and low remission rates.Traditional antidepressants demonstrate delayed effects,low cure rate,and inadequate therapeutic effectiveness for man-aging treatment-resistant depression(TRD).Several studies have shown that ketamine,a non-selective N-methyl-D-aspartate receptor(NMDAR)antagonist,can produce rapid and sustained antidepressant effects.Ketamine has demonstrated efficacy for reducing suicidality in TRD patients.However,the pharmaco-logical mechanism for ketamine's antidepressant effects remains incompletely understood.Previous research suggests that the an-tidepressant effects of ketamine may involve the monoaminergic,glutamatergic and dopaminergic systems.This paper provides an overview of the pharmacological mechanism for ketamine's anti-depressant effects and discuss the potential directions for future research.

Glutamate,norepinephrine,and their receptors com-prise the glutamatergic and norepinephrine systems,which mu-tually affect each other and play essential roles in mediating vari-ous neuropsychiatric diseases.This paper reviews the functions of N-methyl-D-aspartate receptor(NMDA-R)and α2-adrenergic receptor(α2-AR)and their functional crosstalk at the molecular level in brain in common neuropsychiatric diseases,which would benefit our understanding of neuropathophysiology of psychiatric diseases,drug development and optimization of clinical neuro-psychopharmacology.

Objective To explore the risk factors related to afterload mismatch(AM)after transcatheter mitral valve repair(MitraClip).Methods This was a retrospective cohort study.48 patients hospitalized in the Department of Cardiovascular Medicine,the First Affiliated Hospital of Sun Yat-sen University from December 2021 to December 2023,who underwent MitraClip due to severe mitral regurgitation(MR)were included.Preoperative clinical data,laboratory tests,and preoperative and postoperative color Doppler echocardiographic examination results of surgical patients were collected.AM was defined as the left ventricular ejection fraction(LVEF)decreased by 15％or more after surgery compared with the one before(dLVEF≤-15％).Patients were divided into AM group and non-AM group according to whether afterload mismatch occurred.Univariate and multivariate logistic regression were used to analyze the risk factors of postoperative AM.Results Among 48 patients who underwent MitraClip,14 of them(29.2％)developed afterload-mismatched.For those without AM,their overall LVEF was improved after the operation;for patients in both AM group and non-AM group,their overall left ventricular end-diastolic diameter(LVEDd),left ventricular end-diastolic diameter volume index(LVEDVi)was reduced compared with the preoperative ones.Univariate regression analysis showed that C-reactive protein levels(OR 1.98,95％CI 1.02-3.83),platelets(OR 2.22,95％CI 1.08-4.53),systemic immune inflammation index(OR 1.96,95％CI 1.03-3.71)were associated with an increased risk of AM in patients undergoing MitraClip(all P＜0.05),while those with larger right atrial diameter(OR 0.35,95％CI 0.13-0.93)or moderate to severe tricuspid regurgitation(OR 0.19,95％CI 0.05-0.81)were less likely to develop into AM(both P＜0.05),which is still satisfied after adjustment.Conclusions For patients who underwent MitraClip,C-reactive protein levels,platelets and systemic immune inflammation index(SII)are associated with an increased risk of afterload mismatched,while those with larger right atrial diameter or moderate to severe tricuspid regurgitation were less likely to develop into AM.

Objective:To investigate the relationship and clinical significance of circulating tu-mor DNA(ctDNA)methylation with postoperative recurrence of thyroid cancer.Method:5 pa-tients with recurrent thyroid cancer in our hospital from March 2021 to April 2022 were selected as the observation group,and 2 healthy volunteers were selected as the control group.The level of ctDNA methylation in peripheral blood of the two groups was detected by Illumina high-throughput sequencing system.Gene ontology(GO)function analysis and Kyoto gene and genome encyclope-dia(KEGG)signal pathway analysis were carried out on the methylation region genes with signifi-cant differences through the DAVID gene function analysis platform.Result:There were 7787 dif-ferential ctDNA methylation sites between the two groups.2914(37.4％)were hypermethylation sites and 4873(62.6％)were low methylation sites.GO functional analysis showed that differentially methylated genes were enriched in molecular functions such as DNA-binding transcriptional acti-vation,cell-substrate adhesion,glycoprotein complex and other cellular components.KEGG path-way analysis showed that differentially methylated genes were enriched in thyroid carcinoma signal pathway,cell adhesion molecules,RAP1 signal pathway,RAS signal pathway,MAPK signal path-way and so on.Conclusion:ctDNA methylation may be involved in cancer recurrence in postop-erative patients with thyroid cancer.Monitoring the level of ctDNA methylation in peripheral blood may be an effective method to indicate the recurrence or metastasis of thyroid cancer and guide clinical diagnosis and treatment.

Objective:To investigate the effect of spouse smoking cessation(SSC)on the pregnancy outcome of the patients with polycystic ovary syndrome(PCOS)based on a secondary analysis of the results of a large randomized clinical trial.Methods:Basedon the inclusion and exclusion criteria,this secondary analysis included 861 female participants in the Trial of Acu-puncture Combined with Clomiphene for PCOS from 2011 to 2015.According to the smoking status of their husbands,we divided the subjects into a smoking group(n=345),a non-smoking group(n=387),and a smoking cessation group(n=129),collected their general demographics,anthropometric indexes,laboratory results and pregnancy outcomes,compared them among the three groups,and analyzed the relationship of SSC with the pregnancy outcomes of the PCOS patients.Results:The levels of total testos-terone(T)and low-density lipoprotein cholesterol(LDL-C)in the smoking cessation group were similar to those in the non-smoking group,but significantly lower than those in the smoking group(P=0.014 and P=0.011).The contents of fasting insulin,total cho-lesterol,and apolipoprotein B exhibited statistically significant differences among the three groups(P=0.029,P=0.018 and P=0.024),dramatically lower in the smoking cessation and non-smoking groups than in the smoking group,but similar between the for-mer two.The ovulation rate of the smoking cessation group was similar to that of the non-smoking group,remarkably higher than that of the smoking group(P=0.038).No statistically significant differences were observed in other indicators among the three groups(P＞0.05).Multivariate logistic regression analysis showed that SSC during pregnancy preparation was a protective factor for ovulation in the PCOS patients(OR=1.74,95％CI:1.04-2.92,P=0.035).Conclusion:SSC can improve androgen and glucolipid me-tabolisms of infertile patients with PCOS,and thereby significantly increase the ovulation rate.It is of positive significance to encourage SSC clinically for improving the pregnancy outcomes of infertile women with PCOS.

The advantages of fluorescence detection of uric acid were introduced compared to the traditional detection methods.The preparation process,detection principle and performance of organic,inorganic and organic-inorganic hybrid fluorescent probes were reviewed.The advantages and disadvantages of kinds of fluorescent probes were analyzed when used for uric acid detection,and the futural directions were pointed out for related research.[Chinese Medical Equipment Journal,2024,45(6):93-104]

Objective To investigate the incidence rate,clinical characteristics,and prognosis of neonatal stroke in Shenzhen,China.Methods Led by Shenzhen Children's Hospital,the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022.The incidence,clinical characteristics,treatment,and prognosis of neonatal stroke in Shenzhen were analyzed.Results The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137,1/6 060,and 1/7 704,respectively.Ischemic stroke accounted for 75％(27/36);boys accounted for 64％(23/36).Among the 36 neonates,31(86％)had disease onset within 3 days after birth,and 19(53％)had convulsion as the initial presentation.Cerebral MRI showed that 22 neonates(61％)had left cerebral infarction and 13(36％)had basal ganglia infarction.Magnetic resonance angiography was performed for 12 neonates,among whom 9(75％)had involvement of the middle cerebral artery.Electroencephalography was performed for 29 neonates,with sharp waves in 21 neonates(72％)and seizures in 10 neonates(34％).Symptomatic/supportive treatment varied across different hospitals.Neonatal Behavioral Neurological Assessment was performed for 12 neonates(33％,12/36),with a mean score of(32±4)points.The prognosis of 27 neonates was followed up to around 12 months of age,with 44％(12/27)of the neonates having a good prognosis.Conclusions Ischemic stroke is the main type of neonatal stroke,often with convulsions as the initial presentation,involvement of the middle cerebral artery,sharp waves on electroencephalography,and a relatively low neurodevelopment score.Symptomatic/supportive treatment is the main treatment method,and some neonates tend to have a poor prognosis.

The correlations of global/local properties of brain networks with gambling behavioral scales in depression are explored.The task-state brain functional magnetic resonance imaging data of 24 patients with gambling behavior and depression and 24 healthy controls are analyzed,and preprocessed by SPM software.Graph theory analysis method is used to establish the functional brain networks in which local and global properties are calculated.Two sets of local attribute index including node degree and node efficiency are used to make edge analysis in different depression groups(major,moderate and mild depression groups,with 8 patients in each group)and healthy control group,and the changes in global properties are also discussed.Additionally,the correlations of scoring scale related to gambling behavior with 3 criteria on the global properties(small world attribute,global efficiency and local efficiency)are analyzed.The two-sample t-tests on depression groups and healthy control group confirm the significant connections among brain regions(P＜0.05),and reveal the significant negative correlations between the global brain network attribute indexes and different behavioral scales,which fully verifies the correlation between gambling behavior and depression,and provides the basis for further exploring correlation between the individual behavior attribute and depression,thereby assisting clinical diagnosis and treatment of depression patients.