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 investigate the clinical features of patients with acute-on-chronic liver failure （ACLF）， and to construct a risk scoring table that can accurately predict the prognosis of patients in the early stage. MethodsA retrospective analysis was performed for the clinical data of 502 patients with ACLF who were admitted to Tangdu Hospital， Air Force Medical University， from January 1， 2010 to December 31， 2020 （training set）， and the influencing factors for 28-day mortality rate were identified. The 69 ACLF patients who were admitted to Tangdu Hospital， Air Force Medical University， from January 1 to December 31， 2021 were enrolled as the validation set. The independent-samples t test or the Mann-Whitney U test was used for comparison of continuous data between two groups， and the chi-square test or the Fisher’s exact test was used for comparison of categorical data between two groups. A univariate Cox regression analysis was used to obtain the early warning indicators associated with the 28-day prognosis of ACLF patients， and variance inflation factors were used to assess multicollinearity among predictors； a multivariate Cox regression analysis was used to construct a risk model for ACLF prognosis （mortality）. A risk scoring table for ACLF prognosis （mortality） was developed based on regression coefficients （β） from the model equation and weight assignments in the nomogram. Internal validation and comparison were performed for the risk model for ACLF prognosis （mortality）， the scoring table for ACLF prognosis （mortality）， and other scoring models （Child-Turcotte-Pugh ［CTP］ score， Model for End-Stage Liver Disease ［MELD］ score， MELD combined with serum sodium concentration ［MELD-Na］ score， and integrated MELD ［iMELD］ score） in the training set， while external validation and comprehensive evaluation of the scoring table and the other scoring models were performed in the validation set. The Nagelkerke’s R² test and the Hosmer-Lemeshow test were used to assess the degree of fitting of the risk model for ACLF prognosis （mortality）， the scoring table for ACLF prognosis （mortality）， and other scoring models， and fitting curves were plotted. C-index was used to assess the discriminatory ability of the scoring table for ACLF prognosis （mortality） and the other scoring models， and the Z-test was used for comparison of C-index between different models. The decision curve analysis was used to compare the clinical benefits of the scoring table for ACLF prognosis （mortality） and the other scoring models. ResultsThe multivariate Cox regression analysis showed that age （hazard ratio ［HR］=1.027， 95% confidence interval ［CI］： 1.015 — 1.039， P<0.001）， hepatic encephalopathy grade （grade 1： HR=2.928， 95%CI： 1.463 — 5.858， P=0.002； grade 2： HR=3.811， 95%CI： 2.078 — 6.988， P<0.001； grade 3： HR=3.916， 95%CI： 1.917 — 8.001， P<0.001； grade 4： HR=6.966， 95%CI： 4.559 — 10.644， P<0.001）， an increase in total bilirubin （TBil） by ≥17.1 μmol/L per day （HR=1.771， 95%CI： 1.248 — 2.513， P=0.001）， creatinine （HR=1.005， 95%CI： 1.004 — 1.006， P<0.001）， neutrophil count （HR=1.092， 95%CI： 1.060 — 1.126， P<0.001）， and international normalized ratio （HR=1.298， 95%CI： 1.187 — 1.418， P<0.001） were independent risk factors associated with the 28-day mortality rate of ACLF patients， and a risk scoring table was constructed for ACLF prognosis （mortality）. The Nagelkerke’s R² test showed that the risk scoring table for ACLF prognosis （mortality） had an R² value of 0.599 in the training set and 0.722 in the validation set， which were higher than the R² values of CTP， MELD， MELD-Na， and iMELD scores. The Hosmer-Lemeshow test showed that the risk scoring table for ACLF prognosis （mortality） had a P value of 0.280 in the training set and 0.788 in the validation set. The C-index analysis showed that the scoring table had a higher C-index than the other scoring models in the validation set （all P<0.001）， as well as a higher C-index than CTP score in the training set （P<0.001）. The decision curve analysis showed that the risk scoring table for ACLF prognosis （mortality） had higher clinical net benefits than the other scoring models. ConclusionCompared with other scoring models currently used in clinical practice， the novel risk scoring table for ACLF prognosis （mortality） constructed based on the six predictive factors of age， hepatic encephalopathy grade， an increase in TBil by ≥17.1 μmol/L per day， creatinine， neutrophil count， and international normalized ratio has a relatively high value in predicting the 28-day prognosis of ACLF patients.

Objective:To investigate the effect of bone marrow mesenchymal stem cells(BMSCs)on the proliferation and collagen expression levels of L929 cells,and to clarify its related mechanism.Methods:The BMSCs were extracted from the 4-week-old C57BL/6 mice.The phenotypes of BMSCs were identified by immunofluorescence staining.The L929 cells were divided into control group(L929 cells),co-culture group(L929 cells and BMSCs),inhibitor of Janus kinase(JAK)WP1066 group(WP1066-treated L929 cells and BMSCs),and dimethyl sulfoxide(DMSO)group(DMSO-treated L929 cells and BMSCs).Cell counting kit-8(CCK-8)assay was used to detect the proliferation activities of the L929 cells in various groups at different time points;Western blotting method was used to detect the expression levels of type Ⅰ collagen(Col Ⅰ)and type Ⅲ collagen(Col Ⅲ)in the L929 cells in various groups;immunofluorescence staining was used to detect the expressions of Col Ⅰ and Col Ⅲ proteins in the L929 cells in various groups.Results:The fluorescence assay results of surface antigen(SA)showed that the surface markers CD29+,CD45-,CD90+and CD105+were found in the BMSCs.The CCK-8 assay results showed that compared with control group,the proliferation activities of the L929 cells in co-culture group and DMSO group were significantly increased(P＜0.01);compared with co-culture group,the proliferation activity of the L929 cells in WP1066 group was significantly decreased(P＜0.01).The Western blotting method results showed that compared with control group,the expression levels of Col Ⅰ and Col Ⅲ proteins in the L929 cells in co-culture group and DMSO group were significantly increased(P＜0.01);compared with co-culture group,the expression levels of Col Ⅰ and Col Ⅲ proteins in the L929 cells in WP1066 group were significantly decreased(P＜0.01);compared with DMSO group,the expression levels of Col Ⅰ and Col Ⅲ proteins in the L929 cells in WP1066 group were significantly decreased(P＜0.01).The immunofluorescence staining results showed that compared with control group,the fluorescence intensities of Col Ⅰ and Col Ⅲ proteins in the L929 cells in co-culture group and DMSO group were significantly increased(P＜0.01);compared with co-culture group,the fluorescence intensities of Col Ⅰ and Col Ⅲ in the L929 cells in WP1066 group were significantly decreased(P＜0.01);compared with DMSO group,the fluorescence intensities of Col Ⅰ and Col Ⅲ in the L929 cells in WP1066 group were significantly decreased(P＜0.01).Conclusion:MSCs can promote the proliferation and collagen production of the L929 cells of the mice through the JAK2/signal transducer and activator of transcription 3(STAT3)signaling pathway.

Sarin(GB)is a typical representative of nerve agents with high toxicity,and very low amount can cause death.GB can cause water and atmospheric environment poisoning,so the detection of GB in water and air is of great significance.In this work,a colorimetric sensor array(CSA)based on GB inhibition of cholinesterase activity was constructed to detect GB with high selectivity.A 4×4 colorimetric array was constructed using acetylcholinesterase(AChE),butyryl cholinesterase(BuChE)and the corresponding substrate acetylthiocholine iodide(S-ACh),butyryl thiocholine iodide(S-BCh),acetylcholine chloride(ACh),butyryl choline chloride(BCh)and 2,6-dichloroindophenol ethyl ester(DCIE).The linear curve of the sensor was Y=131.3×lgC+271.6(R2=0.997),where Y was the array response Euclidean distance,C was the concentration of GB(mg/L),the linear range was 0.03?0.32 mg/L,and the detection limit was 27.6 μg/L.The method could effectively distinguish chemical warfare agents(CWA)such as VX,Soman(GD),mustard gas(HD),Louie reagent(L),and had high anti-interference ability,sensitivity and good repeatability.It was successfully applied to the detection of GB in simulated water and simulated air samples,and the sample recovery rate was 97.2% ?100.9%.This method would be potentially applied to the field rapid detection of nerve agents.

Widespread utilization of glyphosate has led to environmental residues,posing potential threats to ecological systems and human health.Traditional methods for detection of glyphosate are limited by specialized equipment and operational techniques,resulting in inefficient responses.Therefore,it is urgent to develop a convenient,sensitive and accurate detection method for detection of glyphosate.Herein,a new naphthalenesulfonamide-based"Turn-on"fluorescent probe was synthesized using 2-chloroaniline and dansyl chloride as raw materials through a one-step process,which showed a good linear relationship between the glyphosate concentration in concentration range of 0.003-70 μmol/L and the fluorescence intensity(R2=0.995),with a detection limit of 2.73 nmol/L(S/N=3).Analytical techniques such as nuclear magnetic resonance(NMR)spectroscopy and high-resolution mass spectrometry(HRMS)were used to investigate the interaction mechanism between the fluorescent probe and glyphosate.The results indicated that a nucleophilic substitution reaction occurred between the probe and the secondary amine(—NH—)of glyphosate,inducing a photoinduced electron transfer(PET)effect which enhanced the fluorescence intensity by 11.2 times.The probe showed good anti-interference ability towards coexisting metal ions,anions and pesticides in water.When applied to determination of glyphosate in the samples such as tap water,river water(Xiangxi River Reservoir),soil,soybeans,and corn,the spiking recoveries ranged from 94.7％to 109.9％,demonstrating the high accuracy and broad applicability of this detection method.A portable test strip based on this fluorescent probe was developed for rapid semi-quantitative analysis of glyphosate.The developed method was rapid,sensitive,and portable,providing theoretical and technical support for on-site measurement of environmental contaminants.

Combined seawater Hf and Nd isotope compositions have been applied as reliable tracers of water mass mixing and weathering input changes.The establishment of standardized synchronous extraction methods for Fe-Mn oxyhydroxide in sediments,which serve as effective carriers for isotopic signals of ancient seawater,is a prerequisite and key for paleoceanography research.The research material of this study was the surface sediments of the Western Arctic Ocean obtained from China's 7th Arctic Scientific Expedition,and a reliable simultaneous Nd-Hf isotope extraction method in Fe-Mn oxyhydroxide fraction was established through systematic optimization of pretreatment procedures and key extraction parameters.This research focused on analyzing the effects of pretreatment(Milli-Q water pre-wash)and key extraction parameters(leaching time,solution/solid ratios,concentration of EDTA-2Na,and concentration of mixed solution of hydroxyamine hydrochloride(HH)and acetic acid(HAc))on element extraction efficiency and isotopic composition.The experimental results indicated that the Milli-Q water pre-wash was not necessary,Fe-Mn oxyhydroxide extraction could be directly performed.Nd extraction amount in Fe-Mn oxyhydroxide fraction was not sensitive to changes in extraction conditions,while the Hf extraction amount was significantly affected by leaching time,solution/solid ratios and concentration of EDTA-2Na.The optimal conditions for synchronously extracting Nd-Hf isotopes were as follows:adding 20 mL of a mixed solution of 0.005 mol/L HH+1.5%HAc+0.03 mol/L EDTA-2Na per gram of sample,and reaction at room temperature for 3 h under shaking.Through systematic verification of 87Sr/86Sr ratio,εNd value,εHf value,Al/Nd ratio and Al/Hf ratio,it was confirmed that this method could effectively avoid interferences from residual components and accurately obtain Nd-Hf isotope signals of ancient seawater preserved in sediments.The standardized method established in this work provided reliable technical support for reconstructing water mass mixing between the Arctic,North Atlantic,and North Pacific Oceans and riverine input histories.It also provided important reference for the extraction methods of Nd and Hf isotopes from marine sources in sediments from other sea areas around the world.

Objective To investigate the effects of Chaihuang Qingyi Huoxue Granules on multiple organ damage induced by caerulein combined with lipopolysaccharide in mice with severe acute pancreatitis(SAP).Methods Twenty-four C57BL/6J mice were randomly divided into three groups:control(n=8),SAP(n=8)and Chaihuang Qingyi Huoxue Granules(CHQY group,n=8).Mice in SAP and CHQY groups were intraperitoneally injected with caerulein(50 μg/kg)at hourly intervals for 7 consecutive times,followed by an immediate intraperitoneal injection of lipopolysaccharide(10 mg/kg).Mice in control group received an equal volume of normal saline.After the successful establishment of the model,CHQY group mice were administered Chaihuang Qingyi Huoxue Granules[3.185 g/(kg·d)]via gavage,while control and SAP group mice received an equal volume of normal saline.Twenty-four hours post-modeling,mice were anesthetized,and serum was collected and separated for analysis of the activities of amylase(AMY),lipase(LPS),aspartate transaminase(AST),alanine transaminase(ALT)and the contents of creatinine(CREA)and urea(UREA)using an automatic biochemical analyzer.Serum levels of interleukin(IL)-1β,IL-6,IL-8,IL-18,and tumor necrosis factor-α(TNF-α)were measured by ELISA.Tissue samples from pancreas,lung,liver,kidney,and small intestine were collected for histopathological examination using hematoxylin-eosin(HE)staining and scored.The expression of nuclear factor-κB p65(NF-κB p65)was detected in all tissues by immunohistochemistry.Results Compared with control group,the activities of AMY,LPS,AST and ALT,and the contents of CREA,UREA,IL-1β,IL-6,IL-8,IL-18,and TNF-α were increased(P<0.05).Pathological injuries in the pancreas,lung,liver,kidney,and small intestine was significant,with increased pathological scores and a higher proportion of NF-κB p65 positive cells(P<0.05).Compared with SAP group,the activities of AMY,LPS,AST,ALT,and the contents of CREA,UREA,IL-1β,IL-6,IL-8,IL-18,and TNF-α in the serum of CHQY group were decreased(P<0.05).Pathological injuries in the pancreas,lung,liver,kidney and small intestine were reduced,with lower pathological scores and a decreased proportion of NF-κB p65 positive cells(P<0.05).Conclusion Chaihuang Qingyi Huoxue Granules have a certain therapeutic effect on SAP model mice,which may be related to reducing inflammation response and improving multiple organ damage such as the pancreas,lung,liver,kidney and small intestine.

Objective To investigate the risk factors for pneumonia complicating infectious mononucleosis(IM)in adults and construct a nomogram prediction model.Methods A retrospective analysis was conducted on 198 IM patients admitted to the Second Affiliated Hospital of Air Force Medical University from January 2015 to December 2021.Patients were divided into pneumonia group(n=52)and non-pneumonia group(n=146)based on whether pulmonary infection occurred during hospitalization.The baseline data(age,gender,place of onset,etc.),clinical manifestations(maximum body temperature,lymph node enlargement,splenomegaly,etc.),and inflammatory indicators[white blood cell count(WBC),C-reactive protein(CRP),etc.]were compared between the two groups.Kaplan-Meier curves were plotted to analyze the key indicators affecting the hospital stay of IM patients.Multivariate logistic regression was used to analyze the independent risk factors for pneumonia complicating IM in adults and construct a nomogram prediction model based on the identified risk factors.The predictive efficacy of the model was evaluated using the receiver operating characteristic(ROC)curve and the consistency of the model was assessed using the calibration curve.The fit of the model was evaluated using the Hosmer-Lemeshow test.Additionally,the sensitivity,specificity,and accuracy of the model were assessed using confusion matrix.Results Compared with non-pneumonia group,the pneumonia group had a significantly higher proportion of patients from rural areas,with body mass index(BMI)≥24 kg/m2,smoking history,hepatomegaly,fever duration of≥7 d,as well as increased total hospitalization costs and average daily hospitalization costs,and prolonged hospital stay(P<0.05).The proportion of patients with a history of antibiotic use was lower in the pneumonia group(P<0.05).Kaplan-Meier survival analysis showed that patients from rural areas,with BMI≥24 kg/m2,smoking history,no prophylactic use of antibiotics,fever duration≥7 d,and hepatomegaly had significantly prolonged hospital stays(P<0.05).Multivariate logistic regression analysis revealed that living in a rural area(OR=4.089,P<0.05),hepatomegaly(OR=4.082,P<0.05),and elevated WBC(OR=1.205,P<0.05)were independent risk factors for pneumonia complicating IM in adults,while the prophylactic use of antibiotics(OR=0.142,P<0.05)was an independent protective factor.The area under the ROC curve of the constructed nomogram prediction model was 0.827(95%CI 0.762-0.892),and the slope of the calibration curve was close to 1,and the Hosmer-Lemeshow test showed χ2=5.299,P=0.725,indicating good consistency and fit of the prediction model.The results of the confusion matrix assessment showed that the sensitivity of the model was 0.669(0.624-0.773),the specificity was 0.827(0.724-0.930),and the accuracy was 0.732(0.665-0.793).Conclusion The nomogram prediction model based on place of onset,hepatomegaly,the prophylactic use of antibiotics and WBC has excellent fit and discrimination,providing an effective quantitative tool for prognosis assessment of IM.

The discovery of hemoglobin variants with low oxygen affinity,diagnostic methods,prognosis of carriers,and developments in analyzing hemoglobin oxygen-carrying and-releasing abilities are reviewed in this article in order to draw the attention of related clinical departments and to provide references for optimizing the process of diagnosis and treatment.Hemoglobin variants with low oxygen affinity originate from gene mutations encoding hemoglobin and autosomal dominant inheritance.The diagnosis should be combined with clinical manifestations and family history and differentiated from methemoglobinemia.A decrease in pulse oxygen saturation(SpO2)is often the first abnormality observed in asymptomatic carriers of hemoglobin variants with low oxygen affinity.Laboratory examinations include arterial blood gas analysis,hemoglobin oxygen affinity testing,protein analysis and gene sequencing.Most carriers do not require specific treatment and have a good prognosis,who should avoid acute hypoxic injuries induced by strenuous exercise,emotional stress,or high temperature.Moreover,health practitioners should pay attention to their responses to anesthetics,agents that induce oxidative stress,drugs that increase hemoglobin oxygen affinity,and prostacyclins.Hemoglobin oxygen-carrying and-releasing analysis is a promising tool to identify carriers of hemoglobin variants with low oxygen affinity because it does not involve unnecessary or invasive examinations and is of significant values for clinical diagnosis and treatment.

This study aims to explore whether Naoxintong Capsules improve multiple cerebral infarctions and myocardial injury via promoting angiogenesis, thereby exerting a simultaneous treatment effect on both the brain and heart. Male SD rats were randomly divided into six groups: sham-operated group, model group, high-dose, medium-dose, and low-dose groups of Naoxintong Capsules(440, 220, and 110 mg·kg~(-1)), and nimodipine group(10.8 mg·kg~(-1)). Rat models of multiple cerebral infarctions were established by injecting autologous thrombus, and samples were collected and tested seven days after modeling. Evaluations included multiple cerebral infarction model assessments, neurological function scores, grip strength tests, and rotarod tests, so as to evaluate neuromotor functions. Morphological structures of brain and heart tissue were observed using hematoxylin-eosin(HE) staining, Nissl staining, and Masson staining. Network pharmacology was employed to screen the mechanisms of Naoxintong Capsules in improving multiple cerebral infarctions and myocardial injury. Neuronal and myocardial cell ultrastructures were observed using transmission electron microscopy. Apoptosis rate in brain neuronal cells was detected by TdT-mediated dUTP nick end labeling(TUNEL) staining, and reactive oxygen species(ROS) levels in myocardial cells were measured. Immunofluorescence was used to detect the expression of platelet endothelial cell adhesion molecule-1(CD31), antigen identified by monoclonal antibody Ki67(Ki67), hematopoietic progenitor cell antigen CD34(CD34), and hypoxia inducible factor-1α(HIF-1α) in brain and myocardial tissue. Western blot, and real-time quantitative polymerase chain reaction(RT-qPCR) were used to detect the expression of HIF-1α, vascular endothelial growth factor(VEGF), vascular endothelial growth factor receptor 2(VEGFR2), sarcoma(Src), basic fibroblast growth factor(bFGF), angiopoietin-1(Ang-1), and TEK receptor tyrosine kinase(Tie-2). Compared with the model group, the medium-dose group of Naoxintong Capsules showed significantly lower neurological function scores, increased grip strength, and prolonged time on the rotarod. Pathological damage in brain and heart tissue was reduced, with increased and more orderly arranged mitochondria in neurons and cardiomyocytes. Apoptosis in brain neuronal cells was decreased, and ROS levels in cardiomyocytes were reduced. The microvascular density and endothelial cells of new blood vessels in brain and heart tissue increased, with increased overlapping regions of CD31 and Ki67 expression. The relative protein and mRNA expression levels of HIF-1α, VEGF, VEGFR2, Src, Ang-1, Tie-2, and bFGF were elevated in brain tissue and myocardial tissue. Naoxintong Capsules may improve multiple cerebral infarctions and myocardial injury by mediating HIF-1α/VEGF expression to promote angiogenesis.
Animals ; Male ; Drugs, Chinese Herbal/administration & dosage* ; Rats, Sprague-Dawley ; Rats ; Cerebral Infarction/genetics* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Vascular Endothelial Growth Factor A/genetics* ; Capsules ; Signal Transduction/drug effects* ; Humans ; Brain/metabolism* ; Myocardium/metabolism* ; Apoptosis/drug effects*