OBJECTIVE To investigate the impact of vesicular stomatitis virus envelope glycopro-tein-G(VSV-G)modification on the mucosal immune efficacy of antigen-loaded engineered exosome vaccines.METHODS In vitro experiments:Dendritic cells(DCs)were divided into three groups:cell-control(treated with culture medium),receptor binding domain(RBD)(transfected with plasmid RBD),and RBD+VSV-G(co-transfected with plasmids RBD and VSV-G).Expression levels of RBD and VSV-G were assessed using Western blotting,flow cytometry,and immunofluorescence.Exosomes were extracted via ultracentrifugation,whose morphology,size distribution,and marker proteins were analyzed using transmission electron microscopy,nanoparticle tracking analysis,and Western blotting that confirmed the expressions of RBD and VSV-G in the exosomes.In vivo experiments:① Female BALB/c mice were divided into the control group Mock exosomes(Mock-Exo)(derived from the supernatant of cell-control),RBD decorated exosomes(RBD-Exo)(derived from the RBD cell supernatant),and RBD and VSV-G decorated exosomes(RBD+VSV-G-Exo)(derived from RBD+VSV-G cell supernatant).Follow-ing intranasal immunization with the respective vaccines,the nasal retention effects were evaluated using in vivo imaging.Flow cytometry was used to assess the ability to recruit immune cells to the nasal tissue.Serum RBD-specific immunoglobulin G(IgG)and mucosal immunoglobulin A(IgA)(bronchoal-veolar lavage fluid/nasal wash)were quantified at 7 and 21 d post-immunization by enzyme-linked immuno-sorbent assay.Body weight changes were monitored and key serum biochemical parameters along with histopathological damage to major organs were analyzed following immunization.② Female BALB/c mice were divided into the Mock-Exo group(intranasally inoculated with Mock-Exo),RBD+VSV-G-Exo group(intranasally inoculated with RBD+VSV-G-Exo),and RBD+VSV-G-Exo(im)group(intramus-cularly injected with RBD+VSV-G-Exo).RESULTS In vitro experiments:RBD and VSV-G were successfully expressed in cells,with positive rates of RBD+and VSV-G+cells at 64.4%and 31.2%,respectively.The extracted exosomes exhibited regular morphology and qualified purity,with a particle size of approximately 138 nm and successfully loaded RBD and VSV-G proteins.In vivo experiments:Compared to Mock-Exo and RBD-Exo,RBD+VSV-G-Exo prolonged nasal retention time to 96 h and markedly increased the numbers of CD49B+natural killer cells,CD11c+dendritic cells,and F4/80+macrophages in nasal tissues.RBD+VSV-G-Exo induced robust RBD-specific immune responses,with serum IgG titers,BALF IgA titers,and nasal wash IgA titers reaching 1∶5 215,1∶2 560,1∶1 114,respec-tively.In contrast,no RBD-specific IgA antibody titers were detected in the BALF and nasal wash of mice treated with RBD+VSV-G-Exo(im).Mice showed stable body weight gain during 30 d post-immu-nization.Major serum biochemical indices were within normal reference ranges,and no obvious patho-logical changes were observed in major organs or olfactory bulbs 7 d after immunization.CONCLU-SION VSV-G modification extends the retention time of engineered exosome vaccines in nasal tissues,enhance their ability to recruit immune cells,and induce a high-level antigen-specific respiratory mucosal immune response.

OBJECTIVE To investigate the impact of lysosomal associated membrane protein 2b(Lamp2b)modification on the mucosal immune efficacy of engineered exosome-based vaccines.METHODS In vitro experiments:The murine dendritic cell line DC2.4 was transfected with a plasmid encoding the Lamp2b-RBD fusion protein.Real-time quantitative PCR and Western blotting were employed to assess Lamp2b-RBD expressions,flow cytometry was used to evaluate the proportion of Lamp2b-RBD-positive cells,and immunofluorescence staining was performed to determine their membrane localization.Exosomes were isolated via ultracentrifugation,and their morphology and particle size distribution were examined using transmission electron microscopy and nanoparticle tracking analysis.Western blotting was applied to confirm exosomal marker proteins[cluster of differentiation 9(CD9),CD63,ALG-2-interacting protein X(Alix),and Golgi marker GM130]and Lamp2b-RBD expression.In vivo experiments:① Female BALB/c mice were divided into the Lamp2b-RBD-Exo group and the lipid nanoparticle(LNP)group,and administered intratracheally for mucosal immunization.Pulmonary reten-tion was assessed by immunofluorescence staining.② Female BALB/c mice were divided into three groups:placebo group(PBS group),Lamp2b-RBD-Exo intratracheal administration group,and Lamp2b-RBD-Exo intramuscular injection group(im).Immunizations were performed on days 0 and 14,and on days 7 and 21.The titers of RBD-specific immunoglobulin G(IgG)in serum and RBD-specific IgA and IgG antibodies in bronchoalveolar lavage fluid were determined by enzyme-linked immunosor-bent assay(ELISA).RESULTS In vitro experiments:Lamp2b-RBD-positive cells accounted for 71.16％.Lamp2b-RBD mRNA levels were upregulated 1 979-fold compared with controls,with Lamp2b-RBD proteins localized on the cell membrane.Purified engineered exosomes displayed regular morphology,expressed CD9,CD63,and Alix but not GM130,had an average diameter of approximately 124 nm,and carried 3 009 pg of RBD protein per 1×109 exosomes.In vivo experiments:At 4 h after administra-tion,fluorescence signals were observed in the lung tissues of both the Lamp2b-RBD-Exo and LNPs groups.At 24 h,the fluorescence signal in the LNPs group shifted to the liver,while in the Lamp2b-RBD-Exo group,the fluorescence expanded from the trachea to the bronchioles and lung tissue,showing significantly better distribution and retention capacity than the LNPs group.Seven days after immuniza-tion,both the Lamp2b-RBD-Exo and Lamp2b-RBD-Exo(im)groups induced RBD-specific IgG antibody titers.At 21 days after immunization,Lamp2b-RBD-Exo elicited a higher level of RBD-specific immune response,with serum IgG titers reaching 1∶8 100 and bronchoalveolar lavage fluid(BALF)IgA titers reaching 1∶300.No RBD-specific IgA antibody titers were detected in the BALF of the Lamp2b-RBD-Exo(im)group.CONCLUSION Lamp2b-RBD modification enables efficient RBD protein loading and enhances pulmonary retention of engineered exosomes,thereby inducing potent antigen-specific mucosal immune responses.

Objective To explore the challenges faced by online appointment nurses during nasogastric intubation and to provide a reference for improvement of the quality and safety of the services provided by online appointment nursing.Methods A purposive sampling was employed to select 13 online appointment nurses from our hospital who had previously provided home nasogastric intubation services for patients.Semi-structured interviews were conducted with the online appointment nurses.The results acquired from the interviews were analysed using Colaizzi's method.Results Two themes were identified.Theme 1 covered the increased risks of nasogastric intubation due to the patients themselves and home environment,which included 4 sub-themes of difficulties in identification and response due to complex conditions of patient,high risk of a sudden asphyxia with poor resuscitation facility,psychological stress from unfamiliar home environment,and more challenges in risk identification due to limited conditions for performing home-based intubation procedures;Theme 2 covered the coping strategies of online-scheduled nurses,which included the improvement of knowledge and skills in emergency nursing to improve comfidence and judge ability of intubation,the strengthening of nurse-patient communication to build a trust and cooperation,the conduct of thorough assessment to ensure procedural safety,and the use of alternative tools and collaboration with family members.Conclusion Online appointment nurses face challenges and risks from both of the procedures and patients themselves during home based nasogastric intubation.Hospitals and relevant management should actively implement corresponding strategies,provide training and guidance for online appointment nurses,develop relevant regulations,and improve the management mechanisms of the internet platform to ensure the safety of home based nasogastric intubation for online appointment nurses and improve the quality of the"Internet Plus Nursing Services."

Objective: To explore the active components, key targets, and mechanism of action of turnip in alleviating pulmonary fibrosis(PF) based on network pharmacology and animal experiments. Methods: The active components and targets of Brassica rapa L. were screened using the traditional Chinese medicine systems pharmacology database and analysis platform database, and PF-related targets were obtained from disease databases such as online mendelian inheritance of man(OMIM) and DrugBank. The intersection targets were used to construct a protein-protein interaction(PPI) network to identify core targets, followed by gene oncology(GO)/Kyoto encyclopedia of genes and genomes(KEGG) pathway enrichment analysis. In the animal experiments, a bleomycin-induced PF mouse model was established. Pathological changes in lung tissue were evaluated using HE and Masson staining. qRT-PCR was used to detect the mRNA expression of tumor necrosis factor-α(TNF-α), phosphatidylinositol 3-kinase(PI3K), and akstrain transforming 1(AKT1), and immunofluorescence staining was used to measure the protein expression of TNF-α, PI3K, and AKT1. Results: The 68 active components identified in Brassica rapa L. may regulate PI3K-Akt signaling pathway by acting on 89 potential targets such as TNF-α and AKT1. The results of animal experiments showed that polysaccharide of Brassica rapa L.(BRPs) could significantly reduce the degree of bleomycin induced pulmonary fibrosis in mice; HE and Masson staining of lung tissue showed that compared with the model group, the damage of alveolar structure, the infiltration of inflammatory cells and the deposition of collagen fibers in the BRPs treatment group were significantly reduced. Further mechanism studies showed that BRPs could significantly down-regulate the mRNA and protein expression levels of TNF-α, PI3K and AKT1 in lung tissue of pulmonary fibrosis mice. Conclusion Brassica rapa L. can synergistically alleviate pulmonary fibrosis through “multi-component, multi-target and multi-channel” approach; BRPs is one of the main active components, and plays an anti-fibrosis role by inhibiting TNF-α/PI3K Akt signaling pathway.

Objective To explore the challenges faced by online appointment nurses during nasogastric intubation and to provide a reference for improvement of the quality and safety of the services provided by online appointment nursing.Methods A purposive sampling was employed to select 13 online appointment nurses from our hospital who had previously provided home nasogastric intubation services for patients.Semi-structured interviews were conducted with the online appointment nurses.The results acquired from the interviews were analysed using Colaizzi's method.Results Two themes were identified.Theme 1 covered the increased risks of nasogastric intubation due to the patients themselves and home environment,which included 4 sub-themes of difficulties in identification and response due to complex conditions of patient,high risk of a sudden asphyxia with poor resuscitation facility,psychological stress from unfamiliar home environment,and more challenges in risk identification due to limited conditions for performing home-based intubation procedures;Theme 2 covered the coping strategies of online-scheduled nurses,which included the improvement of knowledge and skills in emergency nursing to improve comfidence and judge ability of intubation,the strengthening of nurse-patient communication to build a trust and cooperation,the conduct of thorough assessment to ensure procedural safety,and the use of alternative tools and collaboration with family members.Conclusion Online appointment nurses face challenges and risks from both of the procedures and patients themselves during home based nasogastric intubation.Hospitals and relevant management should actively implement corresponding strategies,provide training and guidance for online appointment nurses,develop relevant regulations,and improve the management mechanisms of the internet platform to ensure the safety of home based nasogastric intubation for online appointment nurses and improve the quality of the"Internet Plus Nursing Services."

OBJECTIVE To study the prevention and control strategies for carbapenem-resistant Acinetobacter bau-mannii(CRAB)infection through inves-tigating an outbreak of CRAB infection in an intensive care unit(ICU),and provide a scientific basis for the prevention and control of such hospital-acquired infections.METHODS Epide-miological investigations were conducted on patients with CRAB infection in the ICU of a hospital from Jul.7 to Jul.29,2023,and microbial sampling,identification and drug sensitivity testing were conducted on suspected con-taminated environments and items.Targeted prevention and control measures were taken to control the outbreak.RESULTS Within a short period,8 patients in this hospital developed CRAB hospital-acquired infection,among whom,the drug resistance profiles of CRAB isolated from the specimens of 7 patients in bed A4,A14,B18,B19,B20,B21 and B22 were consistent.Through environmental hygiene monitoring,CRAB isolated from patient clothing,isolation gowns and medical staff uniforms matched the drug resistance profiles of the seven patient iso-lates.After taking targeted measures,no new CRAB infection cases occurred in Oct.,and CRAB was no longer i-solated from the environment and medical fabrics.CONCLUSIONS The suspected outbreak of CRAB infection may be related to the inadequate management and contamination of medical fabrics.Therefore,in addition to strictly implementing the routine prevention and control measures for multidrug-resistant bacteria,it is also crucial to strengthen the standardized management of medical fabrics for the prevention and control of hospital-acquired in-fections and outbreaks.

OBJECTIVE To investigate the impact of lysosomal associated membrane protein 2b(Lamp2b)modification on the mucosal immune efficacy of engineered exosome-based vaccines.METHODS In vitro experiments:The murine dendritic cell line DC2.4 was transfected with a plasmid encoding the Lamp2b-RBD fusion protein.Real-time quantitative PCR and Western blotting were employed to assess Lamp2b-RBD expressions,flow cytometry was used to evaluate the proportion of Lamp2b-RBD-positive cells,and immunofluorescence staining was performed to determine their membrane localization.Exosomes were isolated via ultracentrifugation,and their morphology and particle size distribution were examined using transmission electron microscopy and nanoparticle tracking analysis.Western blotting was applied to confirm exosomal marker proteins[cluster of differentiation 9(CD9),CD63,ALG-2-interacting protein X(Alix),and Golgi marker GM130]and Lamp2b-RBD expression.In vivo experiments:① Female BALB/c mice were divided into the Lamp2b-RBD-Exo group and the lipid nanoparticle(LNP)group,and administered intratracheally for mucosal immunization.Pulmonary reten-tion was assessed by immunofluorescence staining.② Female BALB/c mice were divided into three groups:placebo group(PBS group),Lamp2b-RBD-Exo intratracheal administration group,and Lamp2b-RBD-Exo intramuscular injection group(im).Immunizations were performed on days 0 and 14,and on days 7 and 21.The titers of RBD-specific immunoglobulin G(IgG)in serum and RBD-specific IgA and IgG antibodies in bronchoalveolar lavage fluid were determined by enzyme-linked immunosor-bent assay(ELISA).RESULTS In vitro experiments:Lamp2b-RBD-positive cells accounted for 71.16％.Lamp2b-RBD mRNA levels were upregulated 1 979-fold compared with controls,with Lamp2b-RBD proteins localized on the cell membrane.Purified engineered exosomes displayed regular morphology,expressed CD9,CD63,and Alix but not GM130,had an average diameter of approximately 124 nm,and carried 3 009 pg of RBD protein per 1×109 exosomes.In vivo experiments:At 4 h after administra-tion,fluorescence signals were observed in the lung tissues of both the Lamp2b-RBD-Exo and LNPs groups.At 24 h,the fluorescence signal in the LNPs group shifted to the liver,while in the Lamp2b-RBD-Exo group,the fluorescence expanded from the trachea to the bronchioles and lung tissue,showing significantly better distribution and retention capacity than the LNPs group.Seven days after immuniza-tion,both the Lamp2b-RBD-Exo and Lamp2b-RBD-Exo(im)groups induced RBD-specific IgG antibody titers.At 21 days after immunization,Lamp2b-RBD-Exo elicited a higher level of RBD-specific immune response,with serum IgG titers reaching 1∶8 100 and bronchoalveolar lavage fluid(BALF)IgA titers reaching 1∶300.No RBD-specific IgA antibody titers were detected in the BALF of the Lamp2b-RBD-Exo(im)group.CONCLUSION Lamp2b-RBD modification enables efficient RBD protein loading and enhances pulmonary retention of engineered exosomes,thereby inducing potent antigen-specific mucosal immune responses.

OBJECTIVE To investigate the impact of vesicular stomatitis virus envelope glycopro-tein-G(VSV-G)modification on the mucosal immune efficacy of antigen-loaded engineered exosome vaccines.METHODS In vitro experiments:Dendritic cells(DCs)were divided into three groups:cell-control(treated with culture medium),receptor binding domain(RBD)(transfected with plasmid RBD),and RBD+VSV-G(co-transfected with plasmids RBD and VSV-G).Expression levels of RBD and VSV-G were assessed using Western blotting,flow cytometry,and immunofluorescence.Exosomes were extracted via ultracentrifugation,whose morphology,size distribution,and marker proteins were analyzed using transmission electron microscopy,nanoparticle tracking analysis,and Western blotting that confirmed the expressions of RBD and VSV-G in the exosomes.In vivo experiments:① Female BALB/c mice were divided into the control group Mock exosomes(Mock-Exo)(derived from the supernatant of cell-control),RBD decorated exosomes(RBD-Exo)(derived from the RBD cell supernatant),and RBD and VSV-G decorated exosomes(RBD+VSV-G-Exo)(derived from RBD+VSV-G cell supernatant).Follow-ing intranasal immunization with the respective vaccines,the nasal retention effects were evaluated using in vivo imaging.Flow cytometry was used to assess the ability to recruit immune cells to the nasal tissue.Serum RBD-specific immunoglobulin G(IgG)and mucosal immunoglobulin A(IgA)(bronchoal-veolar lavage fluid/nasal wash)were quantified at 7 and 21 d post-immunization by enzyme-linked immuno-sorbent assay.Body weight changes were monitored and key serum biochemical parameters along with histopathological damage to major organs were analyzed following immunization.② Female BALB/c mice were divided into the Mock-Exo group(intranasally inoculated with Mock-Exo),RBD+VSV-G-Exo group(intranasally inoculated with RBD+VSV-G-Exo),and RBD+VSV-G-Exo(im)group(intramus-cularly injected with RBD+VSV-G-Exo).RESULTS In vitro experiments:RBD and VSV-G were successfully expressed in cells,with positive rates of RBD+and VSV-G+cells at 64.4%and 31.2%,respectively.The extracted exosomes exhibited regular morphology and qualified purity,with a particle size of approximately 138 nm and successfully loaded RBD and VSV-G proteins.In vivo experiments:Compared to Mock-Exo and RBD-Exo,RBD+VSV-G-Exo prolonged nasal retention time to 96 h and markedly increased the numbers of CD49B+natural killer cells,CD11c+dendritic cells,and F4/80+macrophages in nasal tissues.RBD+VSV-G-Exo induced robust RBD-specific immune responses,with serum IgG titers,BALF IgA titers,and nasal wash IgA titers reaching 1∶5 215,1∶2 560,1∶1 114,respec-tively.In contrast,no RBD-specific IgA antibody titers were detected in the BALF and nasal wash of mice treated with RBD+VSV-G-Exo(im).Mice showed stable body weight gain during 30 d post-immu-nization.Major serum biochemical indices were within normal reference ranges,and no obvious patho-logical changes were observed in major organs or olfactory bulbs 7 d after immunization.CONCLU-SION VSV-G modification extends the retention time of engineered exosome vaccines in nasal tissues,enhance their ability to recruit immune cells,and induce a high-level antigen-specific respiratory mucosal immune response.

OBJECTIVE To study the prevention and control strategies for carbapenem-resistant Acinetobacter bau-mannii(CRAB)infection through inves-tigating an outbreak of CRAB infection in an intensive care unit(ICU),and provide a scientific basis for the prevention and control of such hospital-acquired infections.METHODS Epide-miological investigations were conducted on patients with CRAB infection in the ICU of a hospital from Jul.7 to Jul.29,2023,and microbial sampling,identification and drug sensitivity testing were conducted on suspected con-taminated environments and items.Targeted prevention and control measures were taken to control the outbreak.RESULTS Within a short period,8 patients in this hospital developed CRAB hospital-acquired infection,among whom,the drug resistance profiles of CRAB isolated from the specimens of 7 patients in bed A4,A14,B18,B19,B20,B21 and B22 were consistent.Through environmental hygiene monitoring,CRAB isolated from patient clothing,isolation gowns and medical staff uniforms matched the drug resistance profiles of the seven patient iso-lates.After taking targeted measures,no new CRAB infection cases occurred in Oct.,and CRAB was no longer i-solated from the environment and medical fabrics.CONCLUSIONS The suspected outbreak of CRAB infection may be related to the inadequate management and contamination of medical fabrics.Therefore,in addition to strictly implementing the routine prevention and control measures for multidrug-resistant bacteria,it is also crucial to strengthen the standardized management of medical fabrics for the prevention and control of hospital-acquired in-fections and outbreaks.

Objective:To explore the genetic etiology of a fetus with cryptophthalmos detected by prenatal ultrasonography.Methods:A fetus undergoing induced labor at 32nd gestational week due to absence of bilateral eye fissures detected by prenatal ultrasonography in January 2017 was selected as the study subject. Umbilical cord blood sample from the fetus and peripheral blood samples from its parents were collected for the extraction of genomic DNA. Pathogenic variants were screened through whole exome sequencing (WES) and verified by Sanger sequencing. Pathogenicity of candidate variants was verified by bioinformatic analysis and protein structure simulation. Based on the results of genetic testing, prenatal diagnosis was provided to the couple upon their subsequent pregnancy.Results:The couple had four adverse pregnancies previously. The aborted fetus was the fifth, with fused bilateral upper and lower eyelids, poorly developed eyeballs, adhesion of the cornea with the upper eyelid, low-set ears, and abnormal plantar creases, and was diagnosed with cryptophthalmos. WES and Sanger sequencing revealed that the fetus has harbored compound heterozygous variants of the FREM2 gene, namely c. 4537G>A (p.D1513N) and c.7292C>T (p.T2431M). Both variants were unreported associated with cryptophthalmos previously. Protein structure simulation showed that they may lead to loss of hydrogen bonds in the protein product. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be likely pathogenic (PM1_Supporting+ PM2_Supporting+ PM5+ PP3+ PP4; PM2_Supporting+ PM3+ PP3+ PP4). The mother was performed prenatal diagnosis in her sixth pregnancy based on the variants detected in this family, and delivered a daughter with normal phenotype. Conclusion:The FREM2: c. 4537G>A and c. 7292C>T compound heterozygous variants probably underlay the pathogenesis of cryptophthalmos in this fetus. Above finding has enriched the mutational spectrum of the FREM2 gene.