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 investigate the status of population dynamics and distribution changes of Aedes aegypti in Guangdong Province.Methods Continuous monitoring was conducted from May 2018 to July 2024 in Wushi Town and Qishui Town,Leizhou City,Zhanjiang City,Guangdong Province.Additionally,a survey of the distribution of Ae.aegypti along the Leizhou Peninsula coast was carried out.Results The density of Ae.aegypti in Zhanjiang showed a gradual decline from 2018 to 2024.The last detection of adult Ae.aegypti in Wushi Town was in September 2021,and the last larva was found in October 2023.No Ae.aegypti was detected in Qishui Town during surveys from 2021 to 2024.A survey of 18 coastal villages in the Leizhou Peninsula revealed no detections of Ae.aegypti.Conclusions This study provides a basis for understanding the distribution and population density fluctuations of Ae.aegypti,assessing its invasion risk,and scientifically conducting relevant prevention and control efforts.

Objective To understand the current situation of healthcare-associated infection(HAI)in China,pro-vide data support and decision-making basis for formulating scientific and effective strategies for HAI prevention and control.Methods A nationwide cross-sectional survey on HAI was conducted among various types and levels of medical institutions in China according to a unified protocol of bedside surveys and case investigations.Results In 2024,a total of 5 736 medical institutions and 2 751 765 patients were surveyed.Among them,34 889 HAI cases were identified,with a prevalence rate of 1.27％.The number of HAI episodes was 38 032,and case prevalence rate was 1.38％.The prevalence rate of HAI in medical institutions in different regions of China ranged from 0.66％to 2.35％.Among medical institutions of different scales,those with a bed capacity of ≥900 had the high-est incidence of HAI,reaching 1.65％.The most common infection site was the lower respiratory tract(44.66％),followed by the urinary tract(12.94％),surgical site(9.32％),upper respiratory tract(7.02％),and bloodstream infection(5.78％).The top 3 departments with the highest HAI rates were the general intensive care unit(10.02％),department of neurosurgery(5.51％),and department(group)of hematology(5.34％).A total of 23 238 strains of HAI pathogens were detected,with 10 714 strains(46.10％)from lower respiratory tract speci-mens.The top 5 detected strains were Klebsiella pneumoniae(14.76％),Pseudomonas aeruginosa(13.33％),Escherichia coli(12.79％),Acinetobacter baumannii(9.23％),and Staphylococcus aureus(7.88％).231 944 pa-tients underwent class Ⅰ incision surgery were monitored,with 1 647 cases experienced surgical site infection,and the prevalence rate of surgical site infection was 0.71％.The number of patients who should undergo pathogen de-tection(patients receiving therapeutic and therapeutic combined prophylactic antimicrobial agents)was 715 179,while the actual number was 480 492,with a pathogen detection rate of 67.18％.425 225 patients received patho-genic detection before treatment,with a detection rate of 59.46％.Conclusion The overall HAI prevalence in Chi-na is lower,showing disparities among medical institutions of different regions and scales.Therefore,precise imple-mentation of measures is necessary for HAI prevention and control,with a focus on high-risk institutions and high-risk departments,key areas,and critical procedures.All levels of medical institutions should continuously reduce the incidence of HAI by strengthening monitoring,standardizing the use of antimicrobial agents,and reinforcing basic HAI prevention and control measures.

Objective To understand the current situation of healthcare-associated infection(HAI)in China,pro-vide data support and decision-making basis for formulating scientific and effective strategies for HAI prevention and control.Methods A nationwide cross-sectional survey on HAI was conducted among various types and levels of medical institutions in China according to a unified protocol of bedside surveys and case investigations.Results In 2024,a total of 5 736 medical institutions and 2 751 765 patients were surveyed.Among them,34 889 HAI cases were identified,with a prevalence rate of 1.27％.The number of HAI episodes was 38 032,and case prevalence rate was 1.38％.The prevalence rate of HAI in medical institutions in different regions of China ranged from 0.66％to 2.35％.Among medical institutions of different scales,those with a bed capacity of ≥900 had the high-est incidence of HAI,reaching 1.65％.The most common infection site was the lower respiratory tract(44.66％),followed by the urinary tract(12.94％),surgical site(9.32％),upper respiratory tract(7.02％),and bloodstream infection(5.78％).The top 3 departments with the highest HAI rates were the general intensive care unit(10.02％),department of neurosurgery(5.51％),and department(group)of hematology(5.34％).A total of 23 238 strains of HAI pathogens were detected,with 10 714 strains(46.10％)from lower respiratory tract speci-mens.The top 5 detected strains were Klebsiella pneumoniae(14.76％),Pseudomonas aeruginosa(13.33％),Escherichia coli(12.79％),Acinetobacter baumannii(9.23％),and Staphylococcus aureus(7.88％).231 944 pa-tients underwent class Ⅰ incision surgery were monitored,with 1 647 cases experienced surgical site infection,and the prevalence rate of surgical site infection was 0.71％.The number of patients who should undergo pathogen de-tection(patients receiving therapeutic and therapeutic combined prophylactic antimicrobial agents)was 715 179,while the actual number was 480 492,with a pathogen detection rate of 67.18％.425 225 patients received patho-genic detection before treatment,with a detection rate of 59.46％.Conclusion The overall HAI prevalence in Chi-na is lower,showing disparities among medical institutions of different regions and scales.Therefore,precise imple-mentation of measures is necessary for HAI prevention and control,with a focus on high-risk institutions and high-risk departments,key areas,and critical procedures.All levels of medical institutions should continuously reduce the incidence of HAI by strengthening monitoring,standardizing the use of antimicrobial agents,and reinforcing basic HAI prevention and control measures.

Objective To evaluate the characteristics of different antigen-specific T cell immune responses to severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)after inoculation with 2 doses of SARS-CoV-2 inactivated vaccine for 12 months.Methods Fifteen healthy adults were enrolled in this study and blood samples collected at 12 months after receiving two doses of SARS-CoV-2 inactivated vaccine.The level and phenotypic characteristics of SARS-CoV-2 antigen-specific T lymphocytes were detected by activation-induced markers(AIM)based on polychromatic flow cytometry.Results After 12 months of inoculation with 2 doses of SARS-CoV-2 inactivated vaccine,more than 90%of adults had detectable Spike and Non-spike antigen-specific CD4+ T cells immune responses(Spike:14/15,P=0.0001;Non-spike:15/15,P<0.0001).80%of adults had detectable Spike and Non-spike antigen-specific CD8+ T cells immune responses(Spike:12/15,P=0.0463;Non-spike:12/15,P=0.0806).Antigen-specific CD4+ T cells induced by SARS-CoV-2 inactivated vaccination after 12 months were composed of predominantly central memory(CM)and effector memory 1(EM1)cells.On the other hand,in terms of helper subsets,antigen-specific CD4+ T cells mainly showed T helper 1/17(Th1/17)and T helper 2(Th2)phenotypes.Conclusions SARS-CoV-2 inactivated vaccination generates durable and extensive antigen-specific CD4+ T cell memory responses,which may be the key factor for the low proportion of severe coronavirus disease 2019(COVID-19)infection in China.

Objective:To investigate the clinical efficacy and safety of ferric derisomaltose injection versus iron sucrose injection in the treatment of iron deficiency anemia (IDA) .Methods:A total of 120 patients with iron deficiency anemia admitted from June 2021 to March 2023 were given intravenous iron supplementation with ferric derisomaltose to assess the efficacy and safety of hemoglobin (HGB) elevation before and after treatment. Simultaneously, the clinical effects of iron supplementation with iron sucrose were compared to those of inpatient patients during the same period.Results:Baseline values were comparable in both groups. Within 12 weeks of treatment, the elevated HGB level in the ferric derisomaltose group was higher than that of the iron sucrose group, with a statistical difference at all time points, and the proportion of HGB increased over 20 g/L in the patients treated for 4 weeks was higher (98.7%, 75.9% ). During the treatment with ferric derisomaltose and iron sucrose, the proportion of mild adverse reactions in the ferric derisomaltose group was slightly lower than that of the iron sucrose group, and neither group experienced any serious adverse reactions. The patients responded well to the infusion treatment, with no reports of pain or pigmentation at the injection site.Conclusion:The treatment of IDA patients with ferric derisomaltose has a satisfactory curative effect, with the advantages of rapidity, accuracy, and safety. Therefore, it is worthy of widespread clinical use.

Objective:This study aimed at investigating the efficacy and safety of eltrombopag in the treatment of adult primary immune thrombocytopenia (ITP) and evaluated the factors influencing its efficacy and side effects.Methods:A total of 198 patients with adult ITP who were admitted to Tianjin Medical University General Hospital between January 2018 and March 2022 were retrospectively analyzed. The efficacy of each starting dose of eltrombopag was evaluated, and adverse events were analyzed. The factors influencing efficacy were investigated, including sex, age, adult ITP type, platelet antibodies, and combined drug treatments.Results:Of the 198 patients, 70 males and 128 females with a median age of 45 years (18-88 years) were included; 130 (65.7%) had newly diagnosed adult ITP, 25 (12.6%) had persistent adult ITP, and 43 (21.7%) had chronic adult ITP. The bleeding event scores at baseline were assessed; 84.3% had scores of<4 and 15.7% had scores of ≥4. The eltrombopag response rate (initial response) at 6 weeks was 78.8% (complete response [CR]: 49.0%; CR1: 14.6%; CR2: 15.2%). The median response time to eltrombopag was 7 (7, 14) days. The initial response rates to 25, 50, and 75 mg eltrombopag were 74.1%, 85.9%, and 60.0%, respectively ( P=0.031). The initial response rate to the 50 mg dose was significantly higher than that of the 25-mg and 75-mg doses. Two patients received 100 mg as the starting dose, and their initial response was 0. Regarding dose adjustment, 70.7% of the patients remained on the starting dose, 8.6% underwent dose adjustment to 50 mg, and 6.1% underwent dose adjustment to 75 mg. Another two patients underwent dose adjustment to 100 mg. After dose adjustment, the persistent response rates were 83.6%, 85.3%, and 85.7% for the 25-, 50-, and 75-mg doses, respectively, with no significant difference. After dose adjustment, the sustained efficacy rate for the 100-mg dose (4 patients) was 100.0%. After 6 weeks of treatment with eltrombopag, the overall bleeding score of patients with ITP decreased. The number of patients with a score of ≥4 decreased to 0, the number of patients with a score of<4 decreased, and there was no significant change in the number of patients with a score of 1-2. The most common adverse event associated with eltrombopag was impaired liver function (7.7%). No thrombosis events or other adverse events were observed. ITP type and number of megakaryocytes significantly affected the initial response to eltrombopag. The initial response rates to eltrombopag for newly diagnosed adult ITP, persistent adult ITP, and chronic adult ITP were 85.3%, 56.0%, and 76.2%, respectively ( P=0.003). For megakaryocytes, the initial response rates were 61.8%, 87.1%, and 84.3% ( P=0.009) for the decreased, normal, and increased megakaryocyte groups, respectively. Conclusion:Eltrombopag, as a second-line or higher treatment for adult ITP, has a rapid onset of action and good safety. The initial response rate is significantly higher with a dose of 50 mg than with a dose of 25 mg. Patients with newly diagnosed ITP and those with normal or increased megakaryocyte numbers have a higher initial response rate to eltrombopag.

Objective:To analyze the distribution and drug resistance of pathogens of bacterial bloodstream infection in patients with hematological diseases in the Department of Hematology of Tianjin Medical University General Hospital, and to provide etiological data for clinical empirical anti-infection treatment.Methods:A retrospective analysis was conducted on the general clinical information, pathogenic bacteria and drug susceptibility test results of patients with hematological diseases diagnosed with bacterial bloodstream infection by menstrual blood culture in our center from January 2016 to December 2022.Results:Patients included 498 inpatients, with a total of 639 bacterial strains. Among the patients, 86.9% patients had malignancies, and 76.7% had agranulocytosis. Symptoms of concurrent infections, including those of the respiratory tract, oral mucosa, skin and soft tissues, and abdominal sources were observed in 68.3% patients. Gram-negative bacteria (G -) accounted for 79.0% of the isolated bacteria, and gram-positive bacteria (G +) accounted for 21.0%. The top five isolated pathogens were Klebsiella pneumoniae (22.5%), Escherichia coli (20.8%), Pseudomonas aeruginosa (15.0%), Enterococcus faecium (5.5%), and Stenotrophomonas maltophilum (5.0%). Escherichia coli exhibited a decreasing trend of resistance to quinolones, cephalosporins, and carbapenems. Klebsiella pneumoniae exhibited increasing rates of resistance to quinolones and cephalosporins between 2016 and 2018, but the rated decreased after 2019. The resistance rate to carbapenems exhibited by Pseudomonas aeruginosa was approximately 20%. Carbapenem-resistant strains of Pseudomonas aeruginosa strains were first detected in 2017, with a peak resistance rate of 35.7%, detected in 2019. A 60.0% resistance rate to methicillin was observed in methicillin-resistant coagulase-negative staphylococci (MRCNS), and one case of linezolid-resistant MRCNS was detected. Conclusions:Pathogenic bacteria of bacterial bloodstream infections were widely distributed in our center, and precautions are warranted against carbapenem resistant P. aeruginosa and Klebsiella pneumoniae.

Objective To explore the clinical efficacy and safety of one-stage posterior lesion removal and internal spinal fixation in patients with lumbar Brucellosis spondylitis.Methods The clinical data of 24 patients admitted from October 2017 to October 2022 were retrospectively analyzed,2 patients were lost to follow-up at 10 months after surgery,at the final 22 cases were included in the study,including 13 males and 9 females with an average age of(52.00±6.89)years old,were treated with one-stage posterior lesion removal and internal spinal fixation.The operation time,intraoperative bleeding,follow-up time,ery-throcyte sedimentation rate(ESR)and C-reactive protein(CRP)before and after operation were recorded.The pain visual ana-logue scale(VAS),Oswestry disability index(ODI),the Japanese Orthopaedic Association(JOA)score for neurofunction,American Spinal Injury Association(ASIA)spinal cord injury grade and modified MacNab criteria were ussed to evaluate the efficacy.Results All patients were followed up from 12 to 30 months with an average of(17.41±4.45)months.The operation time was 70 to 155 min with an average of(1 16.59±24.32)min;the intraoperative bleeding volume was 120 to 520 ml with an average of(275.00±97.53)ml.CRP and ESR levels decreased more significantly at 1 week and at the final follow-up than pre-operative levels(P＜0.05).VAS,JOA score and ODI at 1 week and at the latest follow-up were more significantly improved than preoperative results(P＜0.05).There was no significant difference between ASIA preoperative and 1 week after operation(P＞0.05),and a significant difference between preoperative and last follow-up(P＜0.05).In the final follow-up,21 patients had ex-cellent efficacy,1 patient had fair,and there was no recurrence during the follow-up.Conclusion One-stage transpedicular le-sion removal and internal spinal fixation,with few incisions and short operation time,helps the recovery of neurological func-tion,and the prognosis meets the clinical requirements,which can effectively control Brucella spondylitis.