The purpose of this study was to investigate the regulatory effects of biofilm associated non-coding small RNA(sRNA)00085 on the survival and environmental fitness of Listeria monocytogenes.Homologous recombination technology was used to construct a deletion mutant strain(△sRNA 00085)and a complementary strain(C △sRNA 00085)of the sRNA00085 target gene.The differences in biological characteristics were compared among the standard strain,△sRNA 00085,and C△sRNA 00085.The deletion of sRNA00085 led to a significant decrease in biofilm formation capacity and sensitivity to several antibiotics,including penicillin,piperacillin,doxycycline,tetracycline,vancomycin,and cotrimoxazole.However,only the minimum inhibitory concentration(MIC)of tetracycline exhibited a significant decrease in △sRNA00085.Meanwhile,the decreased biofilm formation and antibiotic resistance of the sRNA00085 mutant were restored in the C△sRNA00085 strain.Furthermore,we investigated the transcription levels of tetracycline resistance-related genes in L.monocytogenes.Down-regu-lated transcription of the tetS gene but no significant difference in transcription of the tetA gene were observed in △sRNA 00085 compared with the standard strain and C△sRNA00085.Moreover,the elimination of sRNA00085 did not affect bacterial growth ability or sensitivity to disinfectants.These findings highlight that sRNA00085 plays an important role in the environ-mental adaptability of L.monocytogenes by affecting bacterial biofilm formation and resistance.

Objective:To observe the clinical efficacy and safety of hypomethylating agent therapy in chronic myelomonocytic leukemia(CMML).Methods:From February 2014 to June 2021,the clinical data,efficacy,survival time and safety of CMML patients diagnosed in the Second Hospital of Hebei Medical University and treated with hypomethylating agent therapy were retrospectively analyzed.Results:A total of 25 CMML patients received hypomethylating agent therapy,including 18 cases treated with decitabine(DEC)and 7 cases treated with azacytidine(AZA)as the basic treatment.Among them,20 patients responded,and 7 patients got complete remission(CR).All patients with CR were treated with DEC as the basic treatment.Five cases of CR occurred in the first 4 courses of treatment.After a median follow-up of 16.4(9.4-20.5)months,4 patients with CR progressed to acute myeloid leukemia(AML).The median overall survival(OS)time of 25 CMML patients was 17.4 months(95％CI:12.437-22.363).According to MD Anderson prognostic scoring system(MDAPS),CMML-specific prognostic scoring system(CPSS),CPSS molecular(CPSS-mol),Mayo molecular model(MMM),risk stratification of patients was performed,and the difference only between different risk stratification of MDAPS and survival time was statistically significant.Common adverse reactions of hypomethylating agent therapy in CMML patients included infection,gastrointestinal reaction,hematological toxicity,skin allergy and liver function damage.All patients'symptoms were improved after corresponding treatment.Conclusion:Hypomethylating agent therapy is effective and safe for CMML patients.CR mostly occurs in the first 4 courses of treatment,and hypomethylating agent therapy combined with low-dose chemotherapy can be used for patients who do not respond.Hypomethylating agent therapy can delay the disease,but can't prevent progression.

Objective: The therapeutic benefits of exosomes obtained from mesenchymal stem cells (MSCs) in acute spinal cord injury (SCI) have been demonstrated in recent years, but the precise mechanisms remain unknown. In this study, the efficacy and mechanisms of MSC-derived exosomes (MSC-Exo) in acute SCI were investigated. Methods: By utilizing a BV2 ferroptosis cellular model and an SCI rat model, we investigated the effects of MSC-Exo on iron death related indicators and NF-E2 related factor 2 (Nrf2)/GTP cyclolase I (GCH1)/5,6,7,8-tetrahydrobiopterin (BH4) signaling axis, as well as their therapeutic effects on SCI rats. Results: The results revealed that MSC-Exo effectively inhibited the production of ferrous iron, lipid peroxidation products malonaldehyde and reactive oxygen species, and ferroptosis-promoting factor prostaglandin-endoperoxide synthase 2. Concurrently, they upregulated ferroptosis suppressors FTH-1 (ferritin heavy chain 1), SLC7A11 (solute carrier family 7 member 11), FSP1 (ferroptosis suppressor protein 1), and GPX4 (glutathione peroxidase 4), contributing to enhanced neurological recovery in SCI rats. Further analysis showed the Nrf2/GTP/BH4 signaling pathway’s critical role in suppressing ferroptosis. Additionally, MSC-Exo was found to inhibit lipopolysaccharide-induced ferroptosis in BV2 cells and SCI rats by activating the Nrf2/GCH1/BH4 axis. Conclusion In summary, the study demonstrates that MSC-Exo mitigates microglial cell ferroptosis via the Nrf2/GCH1/BH4 axis, showing potential for preserving and restoring neurological function post-SCI.

AIM To investigate the protective effects of Didang Decoction-containing serum on rat glomerular endothelial cells(RGECs)following high glucose injury.METHODS Rats were given distilled water or Didang Decoction by gavage to prepare the blank serum or Didang Decoction-containing serum.CCK8 method was used to screen the glucose concentration for the modeling and serum concentration of the drug.The RGECs were divided into the blank group,the model group,Didang Decoction group(10%Didang Decoction medicated serum),Dapagliflozin group(normal serum+2 μmol/L Dapagliflozin)and Didang Decoction+Dapagliflozin group(10%Didang Decoction medicated serum+2 μmol/L Dapagliflozin).24 hrs after the drug treatment,the RGECs had their mRNA and protein expressions of Nrf2,HO-1 and NQO-1 detected by RT-qPCR method and Western blot method;their Nrf2 fluorescence expression detected by immunofluorescence method;and their SOD activity and MDA level detected by colorimetric method.RESULTS Compared with the blank group,the model group displayed decreased mRNA and protein expressions of Nrf2,HO-1 and NQO-1 as well as the activity of SOD(P＜0.01),and increased MDA level(P＜0.01).Compared with the model group,the groups intervened with the drugs showed increased mRNA and protein expressions of Nrf2,HO-1 and NQO-1 as well as the activity of SOD(P＜0.05,P＜0.01),and decreased MDA level(P＜0.01).CONCLUSION Didang Decoction-containing serum can protect RGECs from high glucose injury through activating the Nrf2 signaling pathway.

Objective:To preliminarily investigate the applicability of a poliovirus pseudovirus-based neutralization assay in evaluating the immunogenicity of recombinant poliovirus vaccines and their in vivo potency in rats. Methods:Serum samples from rats immunized with recombinant poliovirus vaccines were tested using both the pseudovirus neutralization assay and the live-virus neutralization assay with Sabin strain. The consistency and correlation of the two methods were analyzed using the Kappa test and Spearman′s rank correlation.Results:For the neutralizing antibodies against typeⅠ, Ⅱ, and Ⅲ polioviruses, the Kappa values for consistency analysis of the two methods were 0.914, 1.000, and 0.751, respectively ( P<0.001), and the correlation coefficients ( R values) were 0.833, 0.927, and 0.859, respectively ( P<0.001). Conclusions:The test results of the two methods are consistent and show a good correlation, indicating that the pseudovirus neutralization assay can be applied to evaluating the immunogenicity of poliovirus vaccines and also can be used in rat potency tests.

Objective: The therapeutic benefits of exosomes obtained from mesenchymal stem cells (MSCs) in acute spinal cord injury (SCI) have been demonstrated in recent years, but the precise mechanisms remain unknown. In this study, the efficacy and mechanisms of MSC-derived exosomes (MSC-Exo) in acute SCI were investigated. Methods: By utilizing a BV2 ferroptosis cellular model and an SCI rat model, we investigated the effects of MSC-Exo on iron death related indicators and NF-E2 related factor 2 (Nrf2)/GTP cyclolase I (GCH1)/5,6,7,8-tetrahydrobiopterin (BH4) signaling axis, as well as their therapeutic effects on SCI rats. Results: The results revealed that MSC-Exo effectively inhibited the production of ferrous iron, lipid peroxidation products malonaldehyde and reactive oxygen species, and ferroptosis-promoting factor prostaglandin-endoperoxide synthase 2. Concurrently, they upregulated ferroptosis suppressors FTH-1 (ferritin heavy chain 1), SLC7A11 (solute carrier family 7 member 11), FSP1 (ferroptosis suppressor protein 1), and GPX4 (glutathione peroxidase 4), contributing to enhanced neurological recovery in SCI rats. Further analysis showed the Nrf2/GTP/BH4 signaling pathway’s critical role in suppressing ferroptosis. Additionally, MSC-Exo was found to inhibit lipopolysaccharide-induced ferroptosis in BV2 cells and SCI rats by activating the Nrf2/GCH1/BH4 axis. Conclusion In summary, the study demonstrates that MSC-Exo mitigates microglial cell ferroptosis via the Nrf2/GCH1/BH4 axis, showing potential for preserving and restoring neurological function post-SCI.

Objective: The therapeutic benefits of exosomes obtained from mesenchymal stem cells (MSCs) in acute spinal cord injury (SCI) have been demonstrated in recent years, but the precise mechanisms remain unknown. In this study, the efficacy and mechanisms of MSC-derived exosomes (MSC-Exo) in acute SCI were investigated. Methods: By utilizing a BV2 ferroptosis cellular model and an SCI rat model, we investigated the effects of MSC-Exo on iron death related indicators and NF-E2 related factor 2 (Nrf2)/GTP cyclolase I (GCH1)/5,6,7,8-tetrahydrobiopterin (BH4) signaling axis, as well as their therapeutic effects on SCI rats. Results: The results revealed that MSC-Exo effectively inhibited the production of ferrous iron, lipid peroxidation products malonaldehyde and reactive oxygen species, and ferroptosis-promoting factor prostaglandin-endoperoxide synthase 2. Concurrently, they upregulated ferroptosis suppressors FTH-1 (ferritin heavy chain 1), SLC7A11 (solute carrier family 7 member 11), FSP1 (ferroptosis suppressor protein 1), and GPX4 (glutathione peroxidase 4), contributing to enhanced neurological recovery in SCI rats. Further analysis showed the Nrf2/GTP/BH4 signaling pathway’s critical role in suppressing ferroptosis. Additionally, MSC-Exo was found to inhibit lipopolysaccharide-induced ferroptosis in BV2 cells and SCI rats by activating the Nrf2/GCH1/BH4 axis. Conclusion In summary, the study demonstrates that MSC-Exo mitigates microglial cell ferroptosis via the Nrf2/GCH1/BH4 axis, showing potential for preserving and restoring neurological function post-SCI.

Objective:To investigate the effect and associated mechanism of tumor tissue-infiltrating NK cells after receiving radiotherapy for hepatocellular carcinoma (HCC).Methods:A HCC tumor-bearing mouse model was constructed using human hepatocellular carcinoma cell line (SK-Hep-1) and divided into four groups: control, radiotherapy, NK cell clearance, and NK clearance combined with radiotherapy. Tumor growth condition was simultaneously recorded. The NK cell ratio in peripheral blood and the NK cell intratumoral infiltration condition were detected by flow cytometry and immunohistochemistry. Lentiviral-constructed SK-Hep-1 cells was used to detect the effect of radiotherapy on the regulation of CXCL10 and NK cell chemotaxis following EZH2 overexpression. SK-Hep-1 cells were irradiated in vitro and in vivo. The expression levels of EZH2 and CXCL10 mRNA and protein in the two groups of cell lines and mouse tumor tissues were detected by reverse transcription polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), western blotting (WB), and immunohistochemistry. The chemotaxis and blocking experiments were used to validate the chemotaxis effect of CXCL10 on NK cells. The independent sample t-test was used to compare the groups. P<0.05 was considered statistically significant. Results:The HCC tumor-bearing mouse model experiment showed that HCC tumor growth was most remarkable in the NK clearance combined with the radiotherapy group compared to the radiotherapy group ( P<0.05). Compared with the control group, the number of NK cells in the peripheral blood of nude mice in the radiotherapy group was significantly reduced, while the NK cell intratumoral infiltration was significantly increased ( P<0.05). Flow cytometry and immunohistochemistry showed invitro and invivo expressional alterations. The average expression levels of EZH2 mRNA and protein in hepatocellular carcinoma cell lines and tumor tissues were decreased in the radiotherapy group than the control group and mouse tumor tissues ( P<0.05), while the mRNA and protein expression levels of CXCL10 increased ( P<0.05). The cell supernatant following radiotherapy enhanced NK cell chemotaxis but inhibited CXCL10 neutralization. EZH2 overexpression validated that radiotherapy up-regulated CXCL10 mRNA and down-regulated protein expression levels in in vitro and in vivo experiments ( P<0.05). The chemotactic effect on NK cells was significantly weakened with EZH2 overexpression following radiotherapy. Conclusion:NK cells, as immune effector cells, are directly involved in radiotherapy- activated anti-HCC immunity. Importantly, radiotherapy inhibits EZH2 expression in hepatocellular carcinoma, thereby upregulating CXCL10 expression and enhancing intratumoral NK cell invasion.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Objective To describe the changing trend and related factors of prevalence rates of healthcare-associa-ted infection(HAI)in a tertiary hospital in the past 10 years,and analyze the influencing factors for HAI.Methods A cross-sectional survey on HAI was conducted for 10 consecutive years from 2013 to 2022(one day was selected as the survey day each year),data were collected.The distribution and related factors of prevalence rates of HAI were analyzed by trend-x2 test and Pearson correlation coefficient.Multivariate logistic regression and multilayer percep-tron(MLP)models were constructed to analyze the independent effect and significance of factors.Results From 2013 to 2022,the prevalence rates of HAI ranged from 4.66％to 8.07％in this hospital,showing a linear upward trend.The proportions of ICU patients and utilization rate of central venous catheters within 2 days before the sur-vey showed linear upward trends,while the proportion of patients with urinary catheters within 2 days before the survey and proportion of patients undergoing surgery within 30 days before the survey decreased.The MLP model revealed that the top 3 important factors for HAI were length of hospital stay＞10 days,admission in ICU,and in-dwelling central venous catheters within 2 days before the survey.Multivariate logistic regression model indicated that length of hospital stay＞10 days,indwelling central venous catheters or urinary catheters within 2 days before the survey,surgery within 30 days before the survey,and admission in ICU were independent influencing factors for HAI.Conclusion The incidence of HAI in this hospital presents a linear increase in recent 10 years,the causes should be further analyzed and the direction of intervention should be determined through targeted surveillance.Adopting trend test statistical analysis method,logistic regression,MLP multi-factor model can further explore the data value of HAI prevalence survey.