In the central nervous system (CNS), the myelin sheath, a specialized membrane structure that wraps around axons, is formed by oligodendrocytes through a highly coordinated spatiotemporal developmental program. The process begins with the directed differentiation of neural precursor cells into oligodendrocyte precursor cells (OPCs), followed by their migration, proliferation, differentiation, and maturation, ultimately leading to the formation of a multi-segmental myelin sheath structure. Recent single-cell sequencing research has revealed that this process involves the temporal regulation of over 200 key genes, with a regulatory network composed of transcription factors such as Sox10 and Olig2 playing a central role. The primary function of the myelin sheath is to accelerate nerve signal transmission and protect nerve fibers from damage. Its insulating properties not only increase nerve conduction speed by 50-100 times but also ensure the long-term functional integrity of the nervous system by maintaining axonal metabolic homeostasis and providing mechanical protection. The pathological effects of myelin sheath injury exhibit a cascade amplification pattern: acute demyelination leads to action potential conduction block, while chronic lesions may cause axonal damage and neuronal death in severe or long-term cases, ultimately resulting in irreversible neurological dysfunction with neurodegenerative characteristics. Multiple sclerosis (MS) is a neurodegenerative disease characterized by chronic inflammatory demyelination of the CNS. Clinically, the distribution of lesions in MS exhibits spatial heterogeneity, which is closely related to differences in the regenerative capacity of oligodendrocytes within the local microenvironment. Emerging evidence suggests that astrocytes form a dynamic “neural-immune-metabolic interface” and play a multidimensional regulatory role in myelin development and regeneration by forming heterogeneous populations composed of different subtypes. During embryonic development, astrocytes induce the targeted differentiation of OPCs in the ventricular region through the Wnt/β-catenin pathway. In the mature stage, they secrete platelet-derived growth factor AA (PDGF-AA) to establish a chemical gradient that guides the precise migration of OPCs along axonal bundles. Notably, astrocytes also provide crucial metabolic support by supplying energy substrates for high-energy myelin formation through the lactate shuttle mechanism. In addition, astrocytes play a dual role in myelin regulation. During the acute injury phase, reactive astrocytes establish a triple defense system within 72 h: upregulating glial fibrillary acidic protein (GFAP) to form scars that isolate lesions, activating the JAK-STAT3 regeneration pathway in oligodendrocytes via leukemia inhibitory factor (LIF), and releasing tumor necrosis factor-stimulated gene-6 (TSG-6) to inhibit excessive microglial activation. However, in chronic neurodegenerative diseases, the phenotypic transformation of astrocytes contributes to microenvironmental deterioration. The secretion of chondroitin sulfate proteoglycans (CSPGs) inhibits OPC migration via the RhoA/ROCK pathway, while the persistent release of reactive oxygen species (ROS) leads to mitochondrial dysfunction and the upregulation of complement C3-mediated synaptic pruning. This article reviews the mechanisms by which astrocytes regulate the development and regeneration of myelin sheaths in the CNS, with a focus on analyzing the multifaceted roles of astrocytes in this process. It emphasizes that astrocytes serve as central hubs in maintaining myelin homeostasis by establishing a metabolic microenvironment and signaling network, aiming to provide new therapeutic strategies for neurodegenerative diseases such as multiple sclerosis.

Objective To establish a rapid screening method for 34 emerging contaminants in surface water by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry(UHPLC-Q-TOF-MS).Methods The pretreatment conditions of solid phase extraction(SPE)were op-timized by orthogonal experimental design and the surface water samples were concentrated and ex-tracted by Oasis? HLB and Oasis? MCX SPE columns in series.The extracts were separated by Kine-tex? EVO C18 column,with gradient elution of 0.1%formic acid aqueous solution and 0.1%formic acid methanol solution.Q-TOF-MS'fullscan'and'targeted MS/MS'modes were used to detect 34 emerging contaminants and to establish a database with 34 emerging contaminants precursor ion,prod-uct ion and retention times.Results The 34 emerging contaminants exhibited good linearity in the con-centration range respectively and the correlation coefficients(r)were higher than 0.97.The limit of de-tection was 0.2-10 ng/L and the recoveries were 81.2%-119.2%.The intra-day precision was 0.78%-18.70%.The method was applied to analyze multiple surface water samples and 6 emerging contaminants were detected,with a concentration range of 1.93-157.71 ng/L.Conclusion The method is simple and rapid for screening various emerging contaminants at the trace level in surface water.

To explore the absorption mechanism of APS-Ⅱ in vivo by establishing M cell model. First, Astragalus polysaccharides (APS) was divided into two different molecular weight polysaccharides APS-I ( > 2 000 kDa) and APS-II (10 kDa) by ultrafiltration, and APS-II (10 kDa) was prepared and fluorescently labeled. Meanwhile, M cell model was constructed by Caco-2 cells and Raji cells. The M cell model was treated with transport inhibitors to explore the transport of APS-Ⅱ on M cells. The results show that FITC has been successfully labeled to the end of APS-Ⅱ, and the M cell model was successfully constructed, which found that APS-Ⅱ could be transported by M cells, and four transport inhibitors of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), genistein, dynasore and nocodazole indicated that APS-II may enter cells through clathrin and caveolin-mediated endocytosis.

Thrombosis is a key factor that increases the mortality rate of COVID-19 patients and causes long COVID sequelae. Guanxinning Tablet (GXNT), which is composed of Salvia miltiorrhiza and Ligusticum Chuanxiong, has significant antithrombotic activity, but the similarities and differences between its anti-conventional thrombus and microthrombus induced by COVID-19 remain unclear. In this paper, the main active components, potential targets and mechanisms of GXNT in the treatment of thrombus and microthrombus caused by COVID-19 were preliminarily revealed by using anti-platelet experiments in vitro, network pharmacology analysis, molecular docking technology and molecular biology experiments. The results of platelet aggregation and adhesion experiments in vitro showed that GXNT had significant anti-platelet aggregation and adhesion activities in a dose-dependent manner. Using network pharmacology analysis, it was revealed that salvianolic acid B, tanshinone IIA, caffeic acid and ligustrazine in GXNT could resist thrombus and microthrombus caused by COVID-19 through key targets as the high mobility group box 1 protein (HMGB1), tumor necrosis factor (TNF), interleukin 6 (IL6) and AKT serine/threonine kinase 1 (AKT1). HMGB1 signaling pathway is one of its key common mechanisms. Western blot also indicated that GXNT significantly inhibited the expression of HMGB1 protein in platelets. In summary, this paper explores the similarities and differences between the mechanism of GXNT against conventional thrombus and microthrombus caused by COVID-19 and provides drug reference and theoretical basis for clinical prevention and treatment of long COVID sequelae. The animal experiment has been approved by the Experimental Animal Ethics Committee of Tianjin University of Traditional Chinese Medicine (No. TCM-LAEC2023187g1549).

Objective To explore the effects of long non-coding RNA(lncRNA)HEM2M overexpression on liver injury in mice with non-alcoholic fatty liver disease(NAFLD).Methods Wild-type C57BL/6(WT)mice and myeloid cell-specific HEM2M knock-in(MYKI)mice were fed normal(ND)or high-fat diet(HFD)for 12 weeks.After intraperitoneal glucose tolerance and insulin tolerance tests,the mice were euthanized for detection of liver function indicators in the serum and liver tissue.HE staining and F4/80 immunohistochemical staining were used to examine liver pathologies,and the levels of IL-6,IL-1β,and TNF-α in the liver tissues were determined with ELISA.The mRNA expressions of HEM2M and the markers of M1 macrophages(TNF-α,iNOS,and IL-6)and M2 macrophages(Arg-1,YM-1,and IL-10)were detected using qRT-PCR,and the protein expressions of P-AKT,T-AKT,NLRC4,caspase-1 and GSDMD were assayed using immunoblotting.Caspase-1 activity in the liver tissues was determined with colorimetric measurement and immunofluorescence assay.Results Compared with HFD-fed WT mice,MYKI mice with HFD feeding showed milder liver function damage(P<0.01),alleviated hepatic steatosis,and reduced liver macrophage infiltration,glucose tolerance impairment and insulin resistance(P<0.01).The levels of IL-6,IL-1β,and TNF-α and mRNA expressions of M1 type macrophage markers were significantly decreased(P<0.01)and those of M2 type markers increased(P<0.01)in the liver tissues of HFD-fed MYKI mice,which also showed reduced NLRC4 inflammasome activity,caspase-1 activation,and GSDMD-N protein expression compared with their WT counterparts(P<0.05).Conclusion Overexpression of HEM2M reduces the production of hepatic inflammatory factors,improves insulin resistance and inhibits hepatic NLRC4 inflammasome activation,which leads to reduced hepatic pyroptosis and liver injury in NAFLD mice.

Objective To explore the effects of long non-coding RNA(lncRNA)HEM2M overexpression on liver injury in mice with non-alcoholic fatty liver disease(NAFLD).Methods Wild-type C57BL/6(WT)mice and myeloid cell-specific HEM2M knock-in(MYKI)mice were fed normal(ND)or high-fat diet(HFD)for 12 weeks.After intraperitoneal glucose tolerance and insulin tolerance tests,the mice were euthanized for detection of liver function indicators in the serum and liver tissue.HE staining and F4/80 immunohistochemical staining were used to examine liver pathologies,and the levels of IL-6,IL-1β,and TNF-α in the liver tissues were determined with ELISA.The mRNA expressions of HEM2M and the markers of M1 macrophages(TNF-α,iNOS,and IL-6)and M2 macrophages(Arg-1,YM-1,and IL-10)were detected using qRT-PCR,and the protein expressions of P-AKT,T-AKT,NLRC4,caspase-1 and GSDMD were assayed using immunoblotting.Caspase-1 activity in the liver tissues was determined with colorimetric measurement and immunofluorescence assay.Results Compared with HFD-fed WT mice,MYKI mice with HFD feeding showed milder liver function damage(P<0.01),alleviated hepatic steatosis,and reduced liver macrophage infiltration,glucose tolerance impairment and insulin resistance(P<0.01).The levels of IL-6,IL-1β,and TNF-α and mRNA expressions of M1 type macrophage markers were significantly decreased(P<0.01)and those of M2 type markers increased(P<0.01)in the liver tissues of HFD-fed MYKI mice,which also showed reduced NLRC4 inflammasome activity,caspase-1 activation,and GSDMD-N protein expression compared with their WT counterparts(P<0.05).Conclusion Overexpression of HEM2M reduces the production of hepatic inflammatory factors,improves insulin resistance and inhibits hepatic NLRC4 inflammasome activation,which leads to reduced hepatic pyroptosis and liver injury in NAFLD mice.

Objective To investigate the value of conventional radiological features and CT radiomics model to differentiate pleo-morphic adenoma(PA)from basal cell adenoma(BCA).Methods The imaging data of 97 cases of PA and 40 cases of BCA were analyzed.All patients were divided into a training set(95 cases)and a validation set(42 cases)at a ratio of 7∶3.Radiomics features were extracted and selected from CT enhancement(venous phase)imagings,and a radiomics model was established.Conventional radiological fea-tures were analyzed and a radiological model was established.The DeLong test was used to compare the differences between the two models,and the superior model was combined with clinical data to establish a joint model and plot a nomogram.Results The area under the curve(AUC)of the radiological model training set and validation set were 0.631[95％confidence interval(CI)0.546-0.716]and 0.661(95％CI 0.545-0.776),respectively.The AUC of the radiomics model training set and validation set were 0.903(95％CI 0.837-0.969)and 0.866(95％CI 0.751-0.973),respectively.The DeLong test showed that the radiomics model was superior to the radiological model(P＜0.05).The diagnostic efficacy of the joint model was further improved,with higher clinical benefits.Conclusion The CT radiomics model is superior to the conventional radiological model,and the joint model can accurately identify distinguish PA from BCA,aiding in clinical decision-making.

Objective To evaluate the types and imaging features of early and late complications after liver transplantation.Methods A retro-spective analysis was conducted on the complications imaging data from 124 patients after liver transplantation.The CT and MRI characteristics of these complications was analyzed,categorized based on their occurrence time and type.Results The postoperative complications in the total 124 patients included vascular complication in 85 patients,biliary complication in 78 patients,and parenchy-mal complication in 21 patients.Additionally,the simple and complex complications were exhibited in 43 and 81 patients.Early vas-cular complication accounted for 69.8％,especially 21 cases(91.3％)were with early hepatic artery thrombosis.Bile leakage in 9 cases occurred in the early postoperative period,whereas biliary stenosis in 43 cases and biliary stones in 23 cases were observed in the late postoperative period.All ischemic infarction in 13 cases occurred in the early postoperative period.Among the 10 cases of liver abscess,8 cases were secondary to ischemic necrosis of liver parenchyma,and other 2 cases were secondary to suppurative cholangitis.Addi-tionally,6 cases of liver tumor recurrence were all detected in the late postoperative period.Conclusion The types of complications occurring after liver transplantation vary over time,and CT and MRI can be used to detect and evaluate postoperative complications.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.