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.

ObjectiveNeuroinflammation plays a crucial role in both the onset and progression of ischemic stroke, exerting a significant impact on the recovery of the central nervous system. Excessive neuroinflammation can lead to secondary neuronal damage, further exacerbating brain injury and impairing functional recovery. As a result, effectively modulating and reducing neuroinflammation in the brain has become a key therapeutic strategy for improving outcomes in ischemic stroke patients. Among various approaches, targeting immune regulation to control inflammation has gained increasing attention. This study aims to investigate the role of in vitro induced regulatory T cells (Treg cells) in suppressing neuroinflammation after ischemic stroke, as well as their potential therapeutic effects. By exploring the mechanisms through which Tregs exert their immunomodulatory functions, this research is expected to provide new insights into stroke treatment strategies. MethodsNaive CD4⁺ T cells were isolated from mouse spleens using a negative selection method to ensure high purity, and then they were induced in vitro to differentiate into Treg cells by adding specific cytokines. The anti-inflammatory effects and therapeutic potential of Treg cells transplantation in a mouse model of ischemic stroke was evaluated. In the middle cerebral artery occlusion (MCAO) model, after Treg cells transplantation, their ability to successfully migrate to the infarcted brain region and their impact on neuroinflammation levels were examined. To further investigate the role of Treg cells in stroke recovery, the changes in cytokine expression and their effects on immune cell interactions was analyzed. Additionally, infarct size and behavioral scores were measured to assess the neuroprotective effects of Treg cells. By integrating multiple indicators, the comprehensive evaluation of potential benefits of Treg cells in the treatment of ischemic stroke was performed. ResultsTreg cells significantly regulated the expression levels of both pro-inflammatory and anti-inflammatory cytokines in vitro and in vivo, effectively balancing the immune response and suppressing excessive inflammation. Additionally, Treg cells inhibited the activation and activity of inflammatory cells, thereby reducing neuroinflammation. In the MCAO mouse model, Treg cells were observed to accumulate in the infarcted brain region, where they significantly reduced the infarct size, demonstrating their neuroprotective effects. Furthermore, Treg cell therapy notably improved behavioral scores, suggesting its role in promoting functional recovery, and increased the survival rate of ischemic stroke mice, highlighting its potential as a promising therapeutic strategy for stroke treatment. ConclusionIn vitro induced Treg cells can effectively suppress neuroinflammation caused by ischemic stroke, demonstrating promising clinical application potential. By regulating the balance between pro-inflammatory and anti-inflammatory cytokines, Treg cells can inhibit immune responses in the nervous system, thereby reducing neuronal damage. Additionally, they can modulate the immune microenvironment, suppress the activation of inflammatory cells, and promote tissue repair. The therapeutic effects of Treg cells also include enhancing post-stroke recovery, improving behavioral outcomes, and increasing the survival rate of ischemic stroke mice. With their ability to suppress neuroinflammation, Treg cell therapy provides a novel and effective strategy for the treatment of ischemic stroke, offering broad application prospects in clinical immunotherapy and regenerative medicine.

Background The mental health status of prison officers is crucial to the efficiency, security, and stability of a prison, and it is essential to pay attention to the factors that influence their mental health. Objective To understand the mental health status of prison officers, and analyze how nature exposure affects their mental health problems and a potential mediating role of mental fatigue. Methods A cross-sectional survey was carried out from May to June 2022 among 1392 prison officers from eight prisons in a province, and a total of 1284 valid questionnaires were recovered. The Nature Exposure Scale, Mental Fatigue Scale, and Depression-Anxiety-Stress Scale were used to assess nature exposure, mental fatigue, and mental health indicators among prison officers, and to explore the effect of nature exposure on mental health problems and a potential mediating role of mental fatigue. Results The recruited prison officers showed high levels of depression, anxiety, and stress. The prevalence rates of depression, anxiety, and stress were 59.11% (759/1284), 60.67% (779/1284),and 43.93% (564/1284), respectively. The results of correlation analysis revealed that nature exposure was negatively related with mental fatigue and mental health indicators (depression, anxiety, and stress) (r_s=−0.242, −0.308, −0.235, −0.254, P<0.01), while mental fatigue was positively correlated with mental health indicators (depression, anxiety, and stress) (r_s=0.546, 0.533, 0.536, P<0.01). The PROCESS macro results showed that the level of nature exposure among prison officers negatively associated with depression, anxiety, and stress (β=−0.180, −0.104, −0.123), and mental fatigue played a mediating role, with indirect effects of −0.200, −0.192, and −0.199, respectively. Conclusion The levels of depression, anxiety, and stress of prison officers are higher than those of other occupations. Nature exposure negatively associates with depression, anxiety, and stress, that is, it may directly alleviate the mental health problems of prison officers; and it may also alleviate mental health problems by relieving mental fatigue.

ObjectiveTo investigate the safety and efficacy of endoscopic ultrasound-guided tissue adhesive injection with the assistance of metal clips in the treatment of cirrhotic patients with gastric varices and gastric-renal shunt （GRS）. MethodsThe patients who attended Beijing Ditan Hospital， Capital Medical University， due to liver cirrhosis and gastric varices from February to June 2023 were enrolled， and all patients were confirmed to have GRS and received endoscopic ultrasound-guided tissue adhesive injection with the assistance of metal clips. The primary evaluation index was alleviation or disappearance of varicose veins after surgery， and the secondary evaluation indices were surgical completion and complications. ResultsA total of 11 patients were enrolled in this study， among whom there were 7 male patients and 4 female patients， with a median age of 55 years. Of all patients， 1 had Child class A liver function， 7 had Child class B liver function， and 3 had Child class C liver function. The maximum （median） diameter of the shunt was 8 mm， and the minimum （median） diameter of the shunt was 4 mm. The median blood flow velocity of the target vessel was 11 cm/s before treatment and 5 cm/s after occlusion with metal clips. The median amount of tissue adhesive injected was 2 mL， and the amount of lauromacrogol used was 1 mL. Disappearance of blood flow signals was observed in all patients after surgery （100%）， and the success rate of surgery was 100%. No patient experienced rebleeding after follow-up for 6 weeks. Gastroscopy at 1 month after surgery showed that gastric varices were eradicated or almost disappeared in 9 patients and were alleviated in 2 patients. ConclusionEndoscopic ultrasound-guided tissue adhesive injection with the assistance of metal clips is a feasible， safe， and effective treatment method for cirrhotic patients with gastric varices and GRS.

Tropane alkaloids (TAs) are a class of anticholinergic drugs widely used in clinical practice and mainly extracted from plant, among which Atopa belladonna is the main commercial drug source. It is of great industrial value to obtain TAs in large quantities by plant metabolic engineering. In TAs pathway, cytochrome oxidase CYP82M3 catalyze the synthesis of tropinone and then tropinone reductase I (TRI) compete with TRII for tropinone to form tropine leading to the TAs synthesis (drainage). In this study, based on the "increasing flow and drainage" metabolic engineering strategy, two genes, namely HnCYP82M3 and DsTRI from Hyoscyamus niger and Datura stramonium, respectively, were overexpressed in the hair roots of A. belladonna, with a view to promote the TAs accumulation. The HnCYP82M3 gene was cloned from the root of H. niger, and it encoded amino acid with 91.7% sequence identity with AbCYP82M3 from A. belladonna. Overexpression of HnCYP82M3 alone did not affect the content of TAs in hair roots of A. belladonna, indicating that CYP82M3 was not a key enzyme in TAs biosynthesis. Simultaneous overexpression of HnCYP82M3 and DsTRI greatly promoted the accumulation of the three TAs, and the contents of hyoscyamine, anisodamine and scopolamine were 4.97 times, 2.83 times and 2.19 times that of the control, respectively, and the increase amplitude was greater than that of single overexpression of DsTRI. This study showed that the "increasing flow and drainage" strategy of enzyme genes co-expression at branch points was a promising metabolic engineering method to effectively improve the biosynthesis of TAs in A. belladonna, and laid a theoretical and technical foundation for the large-scale industrial acquisition of TAs.

BACKGROUND:Clinical treatment for colon cancer mainly includes fluorouracil,irinotecan and oxaliplatin-based therapy.Studies have shown that membrane transport proteins such as ATP-binding cassette transport protein of G2(ABCG2)mediate the transport of these drugs.However,when patients develop resistance to these chemotherapeutic drugs,the high expression of ABCG2 leads to a significant decrease in the therapeutic effect and raises the problem of drug resistance in colon cancer.New drugs and treatments are urgently needed to improve the efficacy.Lycium barbarum polysaccharide has a wide range of biological activities.It can be used as anti-tumor drug to overcome the damage to normal cells in the process of chemotherapy and radiotherapy in tumor patients. OBJECTIVE:To explore the reversal effect of Lycium barbarum polysaccharide in combination with oxaliplatin on colon cancer drug-resistant cells through in vitro experiments to investigate the possible molecular mechanism of Lycium barbarum polysaccharide reversal on colon cancer drug-resistant cells. METHODS:Colon cancer cell line HCT116 and oxaliplatin-resistant cell line HCT116-OXR were selected for in vitro experiments.The optimal intervention concentration and intervention time of Lycium barbarum polysaccharide and oxaliplatin were determined by CCK8 assay of cell proliferation.Samples were further divided into the HCT116 control group,HCT116-OXR blank treatment group,Lycium barbarum polysaccharide group(2.5 mg/mL Lycium barbarum polysaccharide),and oxaliplatin group(10 μmol/L oxaliplatin),and Lycium barbarum polysaccharide + oxaliplatin group(2.5 mg/mL Lycium barbarum polysaccharide +10 μmol/L oxaliplatin).Cell apoptosis was detected by flow cytometry.The protein expression levels of phosphomannose isomerase(PMI)and ABCG2 were detected by immunofluorescence and western blot assay.Phosphatidylinositol3-kinase(PI3K),protein kinase B(AKT),B-cell lymphoma 2(Bcl-2)and BCL2-Associated X(Bax)were detected by western blot assay. RESULTS AND CONCLUSION:(1)HCT116-OXR was more sensitive to Lycium barbarum polysaccharide compared to HCT116(P<0.05).(2)Compared with the HCT116-OXR blank group,Lycium barbarum polysaccharide + oxaliplatin could promote apoptosis of HCT116-OXR cells(P<0.05).The protein expression of Bcl-2 was significantly down-regulated(P<0.05);the protein expression of Bax was significantly up-regulated(P<0.05);the protein expression of ABCG2,PMI,PI3K and AKT was significantly down-regulated(P<0.05).(3)These results indicate that Lycium barbarum polysaccharide reverses drug resistance in colon cancer by inhibiting PMI/PI3K/AKT signaling pathway,which lays the foundation for studying the molecular mechanism of Lycium barbarum polysaccharide's sensitizing chemotherapeutic effects.

Objective To investigate the relieving effects of knockdown of long non-coding RNA(lncRNA)taurine up-regulated gene 1 (TUG1) on inhibiting nucleotide binding oligomerization domain like receptor protein 1 (NLRP1) inflammasome and the progression of Alzheimer’ s disease. Methods Wild-type (WT group, 10 mice) or amyloid precursor protein (APP) / presenilin-1 (PS1) transgenic mice (30 mice) with a genetic background of C57 / BL6 aged 9-10 weeks were used in this study. APP / PS1 transgenic mice were randomly divided into model group, model+lncRNA TUG1 short hairpin RNA (shRNA) group and model + shRNA non target (NT) group (n = 10) . Blood samples, cerebral cortex tissues, primary microglial cells and primary astrocytes were collected from mice 12 weeks of age on day 1 (3-month-old) and 32 weeks of age on day 1 (8-month-old), with 5 mice per group at each time point. Real-time PCR analysis was used to detect the expression levels of lncRNA TUG1 and macrophage migration inhibitory factor (MIF) mRNA in cerebral cortex tissues and primary microglial cells, and C1r and C1s mRNA levels in primary astrocytes of 3-month-old and 8-month-old mice in the above 4 groups, respectively. ELISA was used to determine the MIF in plasma samples of the above 4 groups of mice. Primary microglia and astrocytes from the cerebral cortex of 3-month-old and 8-month-old mice were co-cultured. CCK-8 method was used to determine the proliferation ability of the above cells. Western blotting was used to determine the expression levels of MIF, pro interleukin-1β (pro-IL-1β), apoptosis associated speck-like protein containing a caspase recrult domain(ASC), Caspase-1 (p20), Caspase-1 (full), NLRP1 and NLRP3 in cerebral cortex tissues of 3-month-old and 8-month-old mice. Immunofluorescent staining was used to determine amyloid beta(Aβ) in cerebral cortex of 8-month-old mice. Results At the age of 3-month-old and 8-month-old, compared with the WT group, the relative expression level of lncRNA TUG1 and MIF in cerebral cortex tissues and primary microglia of model group mice was significantly up-regulated, with primary microglial cells and astrocytes proliferation ability enhanced (P<0. 05) . Compared with the model group, the relative expression level of lncRNA TUG1 and MIF cerebral cortex tissues and primary microglia of model + lncRNA TUG1 shRNA group were significantly down-regulated, with primary microglial cells and astrocytes proliferation ability decreased (P<0. 05) . Compared with the WT group, MIF factor in the peripheral plasma of model group increased significantly, with pro-IL-1β,ASC,Caspase-1 (p20),Caspase-1 (full), NLRP1 and NLRP3 expression level up-regulated in the model group mice cerebral cortex tissues, with increased Aβ immunofluorescent indensity (P<0. 05) . Compared with the model group, MIF factor in the peripheral plasma, and pro-IL-1β, ASC, Caspase-1 (p20), Caspase-1 (full) and NLRP1 expression in the model + lncRNA TUG1 shRNA group mice cerebral cortex tissues were down-regulated, and Aβ immunofluorescent indensity decreased (P<0. 05), while NLRP3 expression level were not changed (P>0. 05) . There was no significant difference between the model group and the model+shRNA NT group mice of all the above factors (P>0. 05) . Conclusion In APP / PS1 transgenic mice, up-regulation of lncRNA TUG1 and MIF are positively associated with the activation of NLRP1 inflammasome in mice cerebral cortex tissues and primary microglia. Knock-down of lncRNA TUG1 can ameliorate the progression of Alzheimer’ s disease.

Exposure to ionizing radiation intervenes in genomic stability and gene expression,resulting in the disruption of normal metabolic processes in cells and organs by causing complex biolog-ical responses.Altered genomic variations,gene expression and metabolite concentrations in blood or tissue samples reflect systemic radiation damage.With the application of new techniques and exten-sive study on the mechanisms for ionizing radiation damage,related indicators such as chromosomal variation,gene expression,lipid and metabolism are being recognized and promise to be the markers for early diagnosis and prognosis of radiation exposure.Therefore,this article reviews recent progress in and potential applications of biomarkers related to ionizing radiation injury.

Purpose To demonstrate the advantages of non-contrast-enhanced whole-heart coronary magnetic resonance angiography(NCE-CMRA)in evaluating coronary arteries by comparing ultrasonography(US),and to explore the clinical value of NCE-CMRA in the diagnosis of coronary artery lesions of Kawasaki disease(KD)in children.Materials and Methods NCE-CMRA and US imaging data of 41 children with KD from June 2017 to June 2021 who were diagnosed clinically in Lanzhou University Second Hospital were analyzed retrospectively.The display ability of US and NCE-CMRA in coronary arteries were compared.At the same time,the imaging characteristics of NCE-CMRA were analyzed,and the imaging characteristics such as the range and degree of coronary artery lesions displayed by NCE-CMRA were summarized.Results The overall segment display rate of NCE-CMRA in 41 children with KD was 75.6%;the overall segment display rate of US was 46.3%,with statistical difference between the two techniques(χ2=59.04,P<0.001).Regarding the display of the middle and distal segments of coronary arteries,NCE-CMRA had a clear imaging advantage over US(χ2=57.98 and 161.47,P<0.001).In all cases,25 patients(200 segments)had coronary artery lesions,and 94 segments of coronary artery showed different degrees of dilatation,including 8 segments(8.6%)of giant coronary artery aneurysm,35 segments(37.2%)of medium coronary artery aneurysm,and 51 segments(54.2%)of small coronary artery aneurysm or coronary artery dilation.Conclusion NCE-CMRA technology can objectively and accurately display coronary artery in children,and it can specifically evaluate the degree of damage caused by KD.It has important clinical significance in the diagnosis and evaluation of coronary artery lesions in children with KD.

Objective:To discuss the inhibitory effect of diosmetin(DIO)on the ferroptosis induced by the glutathione peroxidase(GSH-Px)inhibitor(1S,3R)-RSL3(RSL3)in spermatocytes GC-2 of the mice,and to clarify the mechanism.Methods:The GC-2 cells were divided into control group,RSL3 group,RSL3+0.8 nmol·L-1 DIO group,RSL3+4.0 nmol·L-1 DIO group,RSL3+20.0 nmol·L-1 DIO group,and RSL3+ferroptosis inhibitor Ferrostain-1(Fer-1)group(200 nmol·L-1 Fer-1).The cells were treated with 0,1,5,10,50,100,500,and 1 000 nmol·L-1 RSL3 solutions,and 0,0.5,0.1,1.0,5.0,10.0,and 50.0 μmol·L-1 DIO solutions,respectively.Additionally,the GC-2 cells were divided into blank group,model group,and treatment group.The GC-2 cells in treatment group were further divided into 0.8,4.0,and 20.0 nmol·L-1 DIO groups,as well as RSL3+0.8 nmol·L-1 DIO group,RSL3+4.0 nmol·L-1 DIO group,and RSL3+20.0 nmol·L-1 DIO group.MTT method was used to detect the survival rates of the GC-2 cells in various groups.The GC-2 cells were treated with 100 nmol·L-1 RSL3 for 0,6,12,24,36,and 48 h;Western blotting method was used to detect the expression levels of ferroptosis-related proteins in the GC-2 cells in various groups;kits were used to detect the activities of superoxide dismutase(SOD),levels of malondialdehyde(MDA),and ratios of glutathione(GSH)to glutathione disulfide(GSSG)in the GC-2 cells in various groups;immunofluorescence method was used to detect the fluorescence intensities of acyl-CoA synthetase long-chain family member 4(ACSL4)protein in the GC-2 cells in various groups.Results:The MTT method results showed that compared with 0 nmol·L-1 RSL3 group,the survival rates of the GC-2 cells in 50,100,500,and 1 000 nmol·L-1 RSL3 groups were significantly decreased(P<0.01);compared with 0 μmol·L-1 DIO group,the survival rates of the GC-2 cells in 0.5,1.0,5.0,10.0,and 50.0 μmol·L-1 DIO groups were significantly decreased(P<0.01),and 100 nmol·L-1 RSL3 with DIO concentration<0.1 μmol·L-1 were selected for the subsequent experiments.Compared with blank group,the survival rates of the GC-2 cells in model group was significantly decreased(P<0.01);compared with model group,the survival rates of the GC-2 cells in RSL3+20.0 nmol·L-1 DIO group was significantly increased(P<0.01).The Western blotting results showed that compared with 0 h,the expression level of GPX4 protein in the GC-2 cells was significantly decreased after treated with RSL3 for 6 h(P<0.01),and the expression level of HO-1 protein was significantly increased after treated with RSL3 for 12 h(P<0.05);after treated with RSL3 for 12 h,the expression levels of GPX4 and FTH1 proteins were significantly decreased(P<0.05 or P<0.01);after treated with RSL3 for 24 h,the expression levels of GPX4 and HO-1 proteins were significantly decreased(P<0.05 or P<0.01);after treated with RSL3 for 36 and 48 h,the expression levels of HO-1 protein were significantly decreased(P<0.01).Therefore,100 nmol·L-1 RSL3 and for 12 h were selected as the experimental condition for the subsequent experiments.Compared with control group,the MDA level in the GC-2 cells in RSL3 group was significantly increased(P<0.01),and the SOD activity and GSH/GSSG ratio were significantly decreased(P<0.05).Compared with RSL3 group,the SOD activities in the cells in RSL3+0.8 nmol·L-1 DIO group,RSL3+4.0 nmol·L-1 DIO group,RSL3+20.0 nmol·L-1 DIO group,and RSL3+Fer-1 group were significantly increased(P<0.05 or P<0.01).The MDA levels in the cells in RSL3+20.0 nmol·L-1 DIO group and RSL3+Fer-1 group were significantly decreased(P<0.05 or P<0.01),and the GSH/GSSG ratio in the cells in RSL3+4.0 nmol·L-1 DIO group,RSL3+20.0 nmol·L-1 DIO group,and RSL3+Fer-1 group were significantly increased(P<0.05 or P<0.01).The immunofluorescence observation results showed that compared with control group,the fluorescence intensity of ACSL4 protein in the GC-2 cells in RSL3 group was significantly increased;compared with RSL3 group,the fluorescence intensities of ACSL4 protein in the cells in RSL3+0.8 nmol·L-1 DIO group,RSL3+4.0 nmol·L-1 DIO group,RSL3+20.0 nmol·L-1 DIO group,and RSL3+Fer-1 group were significantly decreased.The Western blotting results showed that compared with control group,the expression level of HO-1 protein in the cells in RSL3 group was increased(P<0.05),and the expression levels of GPX4 and FTH1 proteins were significantly decreased(P<0.05 or P<0.01);compared with RSL3 group,the expression levels of HO-1 protein in the cells in RSL3+0.8 nmol·L-1 DIO group,RSL3+4.0 nmol·L-1 DIO group,RSL3+20.0 nmol·L-1 DIO group,and RSL3+Fer-1 group were significantly decreased(P<0.05 or P<0.01),and the expression levels of GPX4 and FTH1 proteins were significantly increased(P<0.05 or P<0.01).Conclusion:DIO can alleviate the RSL3-induced ferroptosis in the GC-2 spermatocytes of the mice,and its mechanism may be related to the inhibition of HO-1 protein expression and the upregulation of expressions of GPX4 and FTH1 proteins.