Community-acquired pneumonia （CAP） refers to an infectious inflammation of the lung parenchyma （including the alveolar wall，that is，the broad pulmonary interstitium） acquired outside the hospital. Its common pathogens include streptococcus pneumoniae，respiratory viruses， mycoplasma pneumoniae， and so on. The related factors for the occurrence and development of CAP include patient characteristics （immune function，mucus production and clearance function，coagulation function，physical condition， and comorbidity） and pathogen characteristics （susceptibility，virulence，and antibiotic resistance）. The pathogenesis of CAP lies in immune deficiency，pathogen invasion，inflammatory response disorder，mucus production and clearance disorder， coagulation disorder， and so on. The pathogenesis of CAP in traditional Chinese medicine can be described as "vital Qi deficiency and toxic stasis". Vital Qi deficiency （lack of immunity） is the potential pathogenesis of the disease and easy to be invaded by external pathogens （respiratory pathogens）. Toxic stasis （inflammatory disorder，mucus production and clearance disorder，and coagulation dysfunction） is the key pathogenic factor. Vital Qi deficiency and toxic stasis are intermingled in a state of deficiency and excess，which suggests that the treatment of CAP lies in strengthening vital Qi and eliminating pathogenic factors. This involves strengthening vital Qi in the whole process to consolidate body resistance and nourish promordial Qi. It also involves clearing heat，eliminating phlegm，removing dampness，and dispelling stasis to dispel pathogenic toxins based on the syndrome differentiation. Its action mechanism is to regulate immune and inflammatory responses，resist pathogens，and improve mucus production and clearance， as well as coagulation disorders. Starting from the key pathogenesis of CAP，"vital Qi deficiency and toxic stasis"， this paper discussed the pathogenesis of CAP and summarized the action mechanism of vital Qi strengthening for detoxification in its treatment. It is intended to complement the theoretical system by identifying "vital Qi deficiency and toxic stasis" as the key pathogenesis underlying CAP and the scientific connotation of treating CAP with vital Qi strengthening for detoxification，thereby providing insights for its clinical application.

The purpose of this study was to investigate the effect of medium-chain fatty acids(MC-FAs)caprylic acid(C8∶0)on lipid metabolism of calf hepatocytes.Primary calf hepatocytes were extracted and cultured,and 1.2 mmol/L nonesterified fatty acids(NEFAs)were added to the hep-atocytes to construct a model of hepatic lipid deposition in primary calf hepatocytes,Five process-ing groups have been set up:Control group(Ctrl),NEFA added group(NEFA),C8∶0 1.2 mmol/L treatment group(C8∶0 1.2),NEFA+C8∶0 0.2 mmol/L treatment group(NEFA+C8∶00.2),C8∶0 0.2 mmol/L treatment group(C8∶0 0.2).Stimulate calf liver cells for 12 hours,and the levels of triglyceride(TG),lipid oxidation(MDA),hydrogen peroxide(H2O2)and total SOD activity were detected by biochemical kit,and FAS,a protein related to lipid synthesis,was detec-ted by Western blot.The results showed that compared with the control group,the concentrations of TG,MDA and H2O2 in NEFA group increased significantly(P＜0.01),and the activity of SOD decreased significantly(P＜0.05).The protein expression levels of FAS,ACC1,DGAT2 and SREBP-1C were significantly up-regulated(P＜0.01),while the expression level of CPT1A was significantly down-regulated(P＜0.01).Compared with the NEFA group,the protein expression levels of SREBP-1C and DGAT2 in the NEFA+C8∶0(concentration 0.2 mmol/L)group de-creased significantly(P＜0.05),and the protein expression level of fatty acid β-oxidation related molecule CPT1A was slightly higher than that in the NEFA group,but there was no statistical sig-nificance(P＞0.05),and the MDA level in hepatocytes decreased significantly(P＜0.05).In a word,the results of this study show that C8∶0 has antioxidant effect,which can effectively reduce the liver injury caused by oxidative stress,regulate the expression of liver fat gene,and then pro-tect liver injury.

OBJECTIVE To understand the molecular epidemiological characteristics,antimicrobial sensitivity and resistance mechanisms of Clostridioides difficile in Xi'an region,and provide data support for the prevention and control of C.difficile infection and the rational clinical use of antibiotics.METHODS A total of 87 strains of C.difficile,which were successfully isolated from stool samples collected from 6 hospitals from Oct.2018 to Dec.2022,were tested for virulence genes,population structure and genetic diversity were detected by Multilocus sequence typing(MLST)and Ribotyping(RT)methods,the drug sensitivity was detected by Etest,additionally,amino acid variations in the quinolone resistance-determining regions GyrA and GyrB were detected.RESULTS There were 41 strains(62.12％)with the genotype A+B+CDT—,23 strains(34.85％)with the genotype A-B+CDT—,and 2 strains(3.03％)with the genotype A+B+CDT+.MLST was divided into 25 ST types,and the main types were ST3,ST42 and ST39.There were 37 RT types,mainly were RT012,RT106 and RT001.All strains were sensitive to vancomycin and metronidazole,and the resistance rates to ciprofloxacin,levofloxacin and moxifloxacin were 90.80％,28.73％and 21.84％,respectively.GyrA contains two amino acid variations at Thr82-Ile and Asp205-Glu,and GyrB contains 6 amino acid variations.CONCLUSIONS The predominant toxin-producing strain of C.difficile in Xi'an is of A+B+CDT-genotype and the primary molecular types are ST54/RT012,ST42/RT106,ST3/RT001 and ST37/RT017.No strains resistant to vancomycin or metronidazole are detected.Amino acid variations in GyrA or GyrB of C.difficile are associated with quinolone resistance.To ef-fectively prevent the outbreak of C.difficile infection,it is crucial to enhance molecular epidemiology studies and strengthen antimicrobial resistance surveillance efforts.

BACKGROUND:Oligodendrocyte precursor cells are seed cells for the treatment of white matter damage diseases.Establishing an efficient and stable in vitro differentiation method is an important prerequisite for clinical translational research.OBJECTIVE:To investigate the effect of fibronectin on biological characteristics such as proliferation,migration,and differentiation of oligodendrocyte precursor cells derived from human neural stem cells.METHODS:Human neural stem cells cultured in suspension were digested into single cells using Accutase.The expression of specific markers Nestin,Sox2,Vimentin,CD133,and Musashi was detected by flow cytometry.The single cells of human neural stem cells were resuspended in oligodendrocyte precursor cell medium and seeded in six-well plates coated with different concentrations of fibronectin(0,1,2.5,5,and 10 μg/mL).Accutase digestion was performed after 7 days of culture.Cells were counted by trypan staining.Fibronectin-coated group with the strongest amplification ability and the oligodendrocyte precursor cells without fibronectin-coated group were selected for further tests.The migration ability of the two groups of cells was detected by Transwell.Flow cytometry was used to detect the expression of Olig2,Sox10,and PDGFR-α.Oligodendrocyte precursor cells were induced to differentiate into oligodendrocytes for 3 weeks,and the expression of Galc in differentiated cells was detected by immunofluorescence staining.RESULTS AND CONCLUSION:(1)H uman neural stem cells grew in suspension spheres.Flow cytometry showed that human neural stem cells highly expressed Nestin,Sox2,Vimentin,CD133,and Musashi.(2)The cell bodies of oligodendrocyte precursor cells induced by human neural stem cells were round or oval,with strong refractive nature and bipolar or tertiary protrusions.Compared with the 0 μg/mL fibronectin coating group,there was a significant difference in the amplification ability of oligodendrocyte precursor cells in the 2.5,5,and 10 μg/mL fibronectin coating groups(P＜0.05).The amplification ability of oligodendrocyte precursor cells was the strongest when the fibronectin concentration was 10 μg/mL.(3)Flow cytometry results showed that the oligodendrocyte precursor cell markers 0Iig2,Sox10,and PDGFR-α were highly expressed in the 0 and 10 μg/mL fibronectin coating groups,and there was no significant difference between the two groups(P＞0.05).(4)Transwell chamber assay results showed that compared with the 0 μg/mL fibronectin-coated group,the migration ability of oligodendrocyte precursor cells in the 10 μg/mL fibronectin-coated group was increased(P＜0.01).(5)After 3 weeks of differentiation into oligodendrocytes,oligodendrocyte precursor cells showed complex morphology with multiple branches,grids or membrane sheets.Immunofluorescence staining results showed that there was no statistical difference in the Galc positive rate of oligodendrocytes between the two groups(P＞0.05).These findings indicate that when the concentration of fibronectin coated well plate is 10 μg/mL,the proliferation and migration of oligodendrocyte precursor cells are the strongest,but it does not affect the expression of oligodendrocyte precursor cells-specific markers Olig2,Sox10,and PDGFR-α and their differentiation into oligodendrocytes.

Objective:Conventional myeloid cell staining methodologies were employed to stain splenocytes and peripheral blood cells by fixation and permeabilization and non-fixation and permeabilization methods,respectively,and effects of staining were compared following flow cytometry detection.Methods:Peripheral blood and spleen of three 8-week-old C57 male mice were divided into fixation and permeabilization group and non-fixation and permeabilization group for staining,and flow cytometry was used to detect mean fluorescence intensity(MFI)of each fluorescent antibody and proportion of positive cells.Results:In mouse peripheral blood samples,MFI of 7-AAD-PerCP-Cyanine5.5 and CD147-PE were lower in fixation and permeabilization group than non-fixation and permeabilization group,MFI of F4/80-FITC,MHC Class Ⅱ(I-A/I-E)-APC-R700,Ly-6c-APC-Cy7,CD206-BV421,CD45-BV510,CD11b-BV605,CD11c-BV650 and CD86-BV786 were higher than non-fixation and permeabilization group.Proportions of each immune cell in fixation and permeabilization group and non-fixation and permeabilization group were highly similar.In mouse spleen samples,MFI of antibodies in fixation and permeabilization group were higher than those in non-fixation and permeabilization group,with exception of CD147-PE,which had a lower MFI than non-fixation and permeabilization group;proportions of dendritic cells and Mon/Ly-6clow cells were lower than non-fixation and permeabilization group,whereas proportions of rest myeloid subpopula-tions were higher than non-fixation and permeabilization group.Conclusion:Fixation and permeabilization in peripheral blood cells can improve antibody MFI,but it has little effect on proportion of positive cells.Fixation and permeabilization can enhance antibody MFI in splenocytes,while effect on proportion of each positive cell is more significant.It is advised that when designing staining strate-gies,researchers attempt to choose alternative cell surface antigens for assay or optimize protocols through required pre-experiments in order to acquire stable and dependable results.

Objective:The genotoxicity risk of graphene artificial nerve sheath conduit was systematically evaluated to provide scientific evidence for their clinical safety and to establish methodological references for the genotoxicity assessment of nanomaterial medical devices.Methods:The potential effects of graphene artificial nerve sheath conduit on genetic and chromosomal endpoints were analyzed by integrating bacterial reverse mutation assays,in vitro chromosome aberration assays,mouse lymphoma cell TK gene mutation tests,and mammalian erythrocyte Pig-a gene mutation assays.Results:In the bacterial reverse mutation assay,all plates showed good background growth.There was no significant difference in the average number of revertant colonies between the test group and the negative control group,with a ratio around 1.0.In the in vitro chromosome aberration assay,the chromosomal aberration rate in the test group was less than 5％,showing no significant increase compared to the negative control group.In the mouse lymphoma cell TK gene mutation assay,the mutation frequency in the test group was less than twice that of the negative control group,with no significant difference.In the mammalian erythrocyte Pig-a gene mutation assay,the mutation frequencies of erythrocytes and reticulocytes in the test group were both less than 3× 10-6,showing no significant difference compared to the negative control group.Conclusions:Graphene artificial nerve sheath conduit exhibited no detectable genotoxicity under the tested conditions,the research results can provide reference and guidance for the genotoxicity evaluation of nanomaterial medical devices.

AIM:We investigated the survival,migration and differentiation abilities of human oligodendro-cyte precursor cells(hOPC)in the brains of mice with vascular dementia(VaD),the effects of hOPC on cerebral white matter,and the underlying mechanisms.METHODS:Mouse VaD model was constructed using the bilateral common ca-rotid artery stenosis method,and the mice were randomly divided into sham,VaD and hOPC groups.Eight weeks after model establishment,the mice in VaD and hOPC groups received equal volume of vehicle(PBS)and hOPC solution,re-spectively,through the corpus callosum.Survival,migration and differentiation of hOPC in the brain were observed by im-munofluorescence staining at 4 and 12 weeks after transplantation.Twelve weeks after transplantation,the effects of hOPC on mouse brain white matter were detected by immunofluorescence staining of myelin basic protein(MBP),myelin-associ-ated glycoprotein(MAG),neurofilament protein 200(NF200)and non-phosphorylated neurofilament H(using monoclo-nal antibody SMI32),and by water maze experiments.Paracrine signaling by hOPC was explored using immunofluores-cence staining for vascular endothelial growth factor(VEGF).RESULTS:The hOPC survived in the brains of VaD mice for 12 weeks,migrated to damaged white matter areas,and partially differentiated into mature oligodendrocytes(approxi-mately 64%).Twelve weeks after transplantation,hOPC significantly increased the fluorescence intensity of MBP,MAG,and NF200(P<0.05 or P<0.01)and decreased the fluorescence intensity of SMI32(P<0.01).The VEGF expression in hOPC-treated mice was significantly higher than that in sham and VaD groups(P<0.01).The difference in water maze test performance between hOPC and sham groups was not statistically significant(P>0.05).The mice in hOPC group had a shorter latency than those in VaD group(P<0.05 or P<0.01),and performed more platform crossings than those in VaD group(P<0.05).CONCLUSION:The hOPC can survive,migrate and differentiate in the brains of VaD mice,attenuate cerebral white matter lesions,and improve cognitive function.These improvements may be attributed to cell replacement and paracrine effects.

Objective:An in vivo mammalian hepatocyte Unscheduled DNA Synthesis(UDS)test was used to evaluate the genotoxicity of Cross-linked Sodium Hyaluronate Gel and Bone Repair Materials,providing experimental evidence for establishing a UDS testing method for medical devices and materials.Methods:0.9％sodium chloride injection and cottonseed oil were used as the solvent for test materials and negative control,respectively.N-dimethylnitrosamine(NDMA)was used as the positive control for the early sampling times,and 2-acetylaminofluorene(2-AAF)was used as the positive control for the late sampling times.SD rats were administered a single dose for toxic exposure,and liver tissues were collected at 4 h and 16 h,respectively.Hepatocytes were isolated using collagenase perfusion.After labeling with 5-ethynyl-2'-deoxyuridine(EdU),and the net average fluorescence intensity(NAFI)of cell nuclei and nucleoplasm was measured by fluorescence microscope.Data from 50 cells were used to analyze the DNA repair level.Results:Compared with the negative control groups,the positive control groups(NDMA and 2-AAF)showed highly statistically significant differences in NAFI(P＜0.01),indicating successful induction of DNA damage.There was no statistically significant differences between the cross-linked sodium hyaluronate gel groups,bone repair material groups and the negative control group(P＞0.05),suggesting that these materials did not significantly induce DNA damage under the experimental conditions.Conclusion:This study first applied EdU labeling technology to the in vivo hepatic UDS assay,achieving non-radioactive labeling through click chemistry reactions.Under the conditions of this study,cross-linked sodium hyaluronate gel and bone repair materials did not exhibit genotoxicity.In the follow-up,the sample range can be expanded and the observation period can be prolonged to further improve the genotoxicity evaluation system of medical devices.

BACKGROUND:Oligodendrocyte precursor cells are seed cells for the treatment of white matter damage diseases.Establishing an efficient and stable in vitro differentiation method is an important prerequisite for clinical translational research.OBJECTIVE:To investigate the effect of fibronectin on biological characteristics such as proliferation,migration,and differentiation of oligodendrocyte precursor cells derived from human neural stem cells.METHODS:Human neural stem cells cultured in suspension were digested into single cells using Accutase.The expression of specific markers Nestin,Sox2,Vimentin,CD133,and Musashi was detected by flow cytometry.The single cells of human neural stem cells were resuspended in oligodendrocyte precursor cell medium and seeded in six-well plates coated with different concentrations of fibronectin(0,1,2.5,5,and 10 μg/mL).Accutase digestion was performed after 7 days of culture.Cells were counted by trypan staining.Fibronectin-coated group with the strongest amplification ability and the oligodendrocyte precursor cells without fibronectin-coated group were selected for further tests.The migration ability of the two groups of cells was detected by Transwell.Flow cytometry was used to detect the expression of Olig2,Sox10,and PDGFR-α.Oligodendrocyte precursor cells were induced to differentiate into oligodendrocytes for 3 weeks,and the expression of Galc in differentiated cells was detected by immunofluorescence staining.RESULTS AND CONCLUSION:(1)H uman neural stem cells grew in suspension spheres.Flow cytometry showed that human neural stem cells highly expressed Nestin,Sox2,Vimentin,CD133,and Musashi.(2)The cell bodies of oligodendrocyte precursor cells induced by human neural stem cells were round or oval,with strong refractive nature and bipolar or tertiary protrusions.Compared with the 0 μg/mL fibronectin coating group,there was a significant difference in the amplification ability of oligodendrocyte precursor cells in the 2.5,5,and 10 μg/mL fibronectin coating groups(P＜0.05).The amplification ability of oligodendrocyte precursor cells was the strongest when the fibronectin concentration was 10 μg/mL.(3)Flow cytometry results showed that the oligodendrocyte precursor cell markers 0Iig2,Sox10,and PDGFR-α were highly expressed in the 0 and 10 μg/mL fibronectin coating groups,and there was no significant difference between the two groups(P＞0.05).(4)Transwell chamber assay results showed that compared with the 0 μg/mL fibronectin-coated group,the migration ability of oligodendrocyte precursor cells in the 10 μg/mL fibronectin-coated group was increased(P＜0.01).(5)After 3 weeks of differentiation into oligodendrocytes,oligodendrocyte precursor cells showed complex morphology with multiple branches,grids or membrane sheets.Immunofluorescence staining results showed that there was no statistical difference in the Galc positive rate of oligodendrocytes between the two groups(P＞0.05).These findings indicate that when the concentration of fibronectin coated well plate is 10 μg/mL,the proliferation and migration of oligodendrocyte precursor cells are the strongest,but it does not affect the expression of oligodendrocyte precursor cells-specific markers Olig2,Sox10,and PDGFR-α and their differentiation into oligodendrocytes.

Objective:An in vivo mammalian hepatocyte Unscheduled DNA Synthesis(UDS)test was used to evaluate the genotoxicity of Cross-linked Sodium Hyaluronate Gel and Bone Repair Materials,providing experimental evidence for establishing a UDS testing method for medical devices and materials.Methods:0.9％sodium chloride injection and cottonseed oil were used as the solvent for test materials and negative control,respectively.N-dimethylnitrosamine(NDMA)was used as the positive control for the early sampling times,and 2-acetylaminofluorene(2-AAF)was used as the positive control for the late sampling times.SD rats were administered a single dose for toxic exposure,and liver tissues were collected at 4 h and 16 h,respectively.Hepatocytes were isolated using collagenase perfusion.After labeling with 5-ethynyl-2'-deoxyuridine(EdU),and the net average fluorescence intensity(NAFI)of cell nuclei and nucleoplasm was measured by fluorescence microscope.Data from 50 cells were used to analyze the DNA repair level.Results:Compared with the negative control groups,the positive control groups(NDMA and 2-AAF)showed highly statistically significant differences in NAFI(P＜0.01),indicating successful induction of DNA damage.There was no statistically significant differences between the cross-linked sodium hyaluronate gel groups,bone repair material groups and the negative control group(P＞0.05),suggesting that these materials did not significantly induce DNA damage under the experimental conditions.Conclusion:This study first applied EdU labeling technology to the in vivo hepatic UDS assay,achieving non-radioactive labeling through click chemistry reactions.Under the conditions of this study,cross-linked sodium hyaluronate gel and bone repair materials did not exhibit genotoxicity.In the follow-up,the sample range can be expanded and the observation period can be prolonged to further improve the genotoxicity evaluation system of medical devices.