OBJECTIVE To investigate the serotypes and antimicrobial resistance rate of clinically isolated Salmonel-la in a children's hospital in Suzhou,and to provide reference for the treatment of salmonellosis.METHOD Totally 177 strains of Salmonella isolated from Children's Hospital of Wujiang District from Jan.2021 to Dec.2023 were collected,and the results of serotypes and drug sensitivity of Salmonella were analyzed.RESULTS The male to fe-male isolation rate of Salmonella was 1.39∶1,with a median age of children infection at 1.3(0.8,2.3)years.The highest number of Salmonella strains were isolated in the month of Jun.,followed by Jul.,Aug.,Sep.,Oct.and May,collectively accounting for 82.49％of all isolates.Acute gastroenteritis was manifested in 142 cases(80.22％),with respiratory tract infections in 38 cases(21.47％)and septicemia in 7 cases(3.95％).The differ-ence in detection rates across the three years was not statistically significant(P=0.806).Salmonella Typhimuri-um was the predominant serotype,representing 54.24％of all isolates.The antimicrobial drug with the highest rate of resistance in Salmonella was ampicillin(71.35％,122/171),followed by sulfamethoxazole/metronidazole(43.60％,75/172),and ampicillin/sulbactam(30.23％,52/172),and no imipenem resistant strains were found.29.07％(50/172)of strains showed multidrug resistance.CONCLUSIONS Boys under three years of age are sus-ceptible to Salmonella infections in summer and fall in this region,with Salmonella Typhimurium being the pre-dominant serotype.Clinical attention should be paid to the characteristics of Salmonella infection and drug resist-ance,as well as the early diagnosis and rational use of antimicrobial drugs.

Objective·To investigate the changes in transcriptome and chromatin accessibility during the differentiation of human embryonic stem cells(hESCs)into neural progenitor cells(NPCs)using in vitro differentiation models and high-throughput multi-omics sequencing technologies.Methods·hESCs were first induced to differentiate into NPCs in vitro using the embryoid body formation method,and cells at both stages were collected.The cell phenotypes were identified by reverse transcription-quantitative real-time PCR(RT-qPCR)and immunofluorescence(IF)staining.Transcriptome sequencing(RNA-seq)was conducted to detect and analyze the differentially expressed genes(DEGs)between hESCs and NPCs.The assay for transposase-accessible chromatin with high-throughput sequencing(ATAC-seq)was employed to assess chromatin accessibility changes between hESCs and NPCs.Motif enrichment analysis was performed on differentially accessible chromatin regions to discover potential regulatory transcription factors.Finally,an integrated analysis of RNA-seq and ATAC-seq data and the protein-protein interaction(PPI)network were performed to identify key genes and regulatory pathways involved in the early stages of neural differentiation in vitro.Results·Both RT-qPCR and IF results indicated that the expression levels of pluripotency markers(NANOG and POU5F1)were high at the hESC stage but significantly decreased at the NPC stage,while early neural differentiation markers(PAX6,SOX1,and NES)were minimally expressed at the hESC stage but markedly upregulated at the NPC stage.RNA-seq analysis revealed that compared to the hESC stage,there were 5 597 genes upregulated and 3 654 genes downregulated at the NPC stage.Gene function enrichment analysis showed that the upregulated genes at the NPC stage were enriched in the functions related to neural development.ATAC-seq analysis demonstrated a total of 27 491 genomic regions had significant changes in chromatin accessibility during the differentiation from hESC to NPC,with 12 381 regions showing increased accessibility and 15 110 regions showing decreased accessibility.Motif enrichment analysis revealed that transcription factor genes such as DLX1 and LHX2 might play an important role in the differentiation process from hESCs into NPCs.Integrated analysis of RNA-seq and ATAC-seq data revealed that overlapping genes with high expression at the NPC stage were mainly enriched in axon guidance,forebrain development,and neuron migration.After neural differentiation,the expression levels of CTNND2 and LHX2 genes increased,and the chromatin accessibility of related genomic regions also increased.PPI network analysis indentified candidate downstream genes including PRKACA,CDH2,and ERBB4.Conclusion·The in vitro differentiation model of hESCs combined with high-throughput multi-omics sequencing technologies can be used to depict the changes in transcriptome and chromatin accessibility during the differentiation of hESCs into NPCs.In this process,the expression levels of genes related to axon guidance,forebrain development,and neuronal migration pathways increase and related chromatin accessibility is enhanced.

Objective·To investigate the changes in transcriptome and chromatin accessibility during the differentiation of human embryonic stem cells(hESCs)into neural progenitor cells(NPCs)using in vitro differentiation models and high-throughput multi-omics sequencing technologies.Methods·hESCs were first induced to differentiate into NPCs in vitro using the embryoid body formation method,and cells at both stages were collected.The cell phenotypes were identified by reverse transcription-quantitative real-time PCR(RT-qPCR)and immunofluorescence(IF)staining.Transcriptome sequencing(RNA-seq)was conducted to detect and analyze the differentially expressed genes(DEGs)between hESCs and NPCs.The assay for transposase-accessible chromatin with high-throughput sequencing(ATAC-seq)was employed to assess chromatin accessibility changes between hESCs and NPCs.Motif enrichment analysis was performed on differentially accessible chromatin regions to discover potential regulatory transcription factors.Finally,an integrated analysis of RNA-seq and ATAC-seq data and the protein-protein interaction(PPI)network were performed to identify key genes and regulatory pathways involved in the early stages of neural differentiation in vitro.Results·Both RT-qPCR and IF results indicated that the expression levels of pluripotency markers(NANOG and POU5F1)were high at the hESC stage but significantly decreased at the NPC stage,while early neural differentiation markers(PAX6,SOX1,and NES)were minimally expressed at the hESC stage but markedly upregulated at the NPC stage.RNA-seq analysis revealed that compared to the hESC stage,there were 5 597 genes upregulated and 3 654 genes downregulated at the NPC stage.Gene function enrichment analysis showed that the upregulated genes at the NPC stage were enriched in the functions related to neural development.ATAC-seq analysis demonstrated a total of 27 491 genomic regions had significant changes in chromatin accessibility during the differentiation from hESC to NPC,with 12 381 regions showing increased accessibility and 15 110 regions showing decreased accessibility.Motif enrichment analysis revealed that transcription factor genes such as DLX1 and LHX2 might play an important role in the differentiation process from hESCs into NPCs.Integrated analysis of RNA-seq and ATAC-seq data revealed that overlapping genes with high expression at the NPC stage were mainly enriched in axon guidance,forebrain development,and neuron migration.After neural differentiation,the expression levels of CTNND2 and LHX2 genes increased,and the chromatin accessibility of related genomic regions also increased.PPI network analysis indentified candidate downstream genes including PRKACA,CDH2,and ERBB4.Conclusion·The in vitro differentiation model of hESCs combined with high-throughput multi-omics sequencing technologies can be used to depict the changes in transcriptome and chromatin accessibility during the differentiation of hESCs into NPCs.In this process,the expression levels of genes related to axon guidance,forebrain development,and neuronal migration pathways increase and related chromatin accessibility is enhanced.

OBJECTIVE To investigate the serotypes and antimicrobial resistance rate of clinically isolated Salmonel-la in a children's hospital in Suzhou,and to provide reference for the treatment of salmonellosis.METHOD Totally 177 strains of Salmonella isolated from Children's Hospital of Wujiang District from Jan.2021 to Dec.2023 were collected,and the results of serotypes and drug sensitivity of Salmonella were analyzed.RESULTS The male to fe-male isolation rate of Salmonella was 1.39∶1,with a median age of children infection at 1.3(0.8,2.3)years.The highest number of Salmonella strains were isolated in the month of Jun.,followed by Jul.,Aug.,Sep.,Oct.and May,collectively accounting for 82.49％of all isolates.Acute gastroenteritis was manifested in 142 cases(80.22％),with respiratory tract infections in 38 cases(21.47％)and septicemia in 7 cases(3.95％).The differ-ence in detection rates across the three years was not statistically significant(P=0.806).Salmonella Typhimuri-um was the predominant serotype,representing 54.24％of all isolates.The antimicrobial drug with the highest rate of resistance in Salmonella was ampicillin(71.35％,122/171),followed by sulfamethoxazole/metronidazole(43.60％,75/172),and ampicillin/sulbactam(30.23％,52/172),and no imipenem resistant strains were found.29.07％(50/172)of strains showed multidrug resistance.CONCLUSIONS Boys under three years of age are sus-ceptible to Salmonella infections in summer and fall in this region,with Salmonella Typhimurium being the pre-dominant serotype.Clinical attention should be paid to the characteristics of Salmonella infection and drug resist-ance,as well as the early diagnosis and rational use of antimicrobial drugs.

Clinical trials are an important method for evaluating the safety and efficacy of in vitro diagnostic reagents, and are a key basis for product registration review and approval. In order to strengthen the management of clinical trials of in vitro diagnostic reagents, the National Medical Products Administration and relevant departments have formulated a series of regulations at the regulatory level, and require applicants and clinical trial institutions to establish a quality management system for clinical trials of in vitro diagnostic reagents. Medical laboratory is the main department and implementer of in vitro diagnostic reagent clinical trials in medical institutions. In recent years, with the rapid development of the in vitro diagnostic industry, the clinical trial projects of in vitro diagnostic reagents conducted by medical laboratory have been increasing day by day. However, there are currently few discussions on the clinical trial of in vitro diagnostic reagents from the perspective of researchers. Therefore, this article summarizes the characteristics of clinical trials of in vitro diagnostic reagents, analyzes the problems and difficulties in conducting clinical trials of in vitro diagnostic reagents in current medical laboratories, and introduces the laboratory′s experience in management; to provide reference for medical testing laboratories that have not yet conducted or have already conducted clinical trials of in vitro diagnostic reagents, in order to improve the quality and efficiency of clinical trials.

Clinical trials are an important method for evaluating the safety and efficacy of in vitro diagnostic reagents, and are a key basis for product registration review and approval. In order to strengthen the management of clinical trials of in vitro diagnostic reagents, the National Medical Products Administration and relevant departments have formulated a series of regulations at the regulatory level, and require applicants and clinical trial institutions to establish a quality management system for clinical trials of in vitro diagnostic reagents. Medical laboratory is the main department and implementer of in vitro diagnostic reagent clinical trials in medical institutions. In recent years, with the rapid development of the in vitro diagnostic industry, the clinical trial projects of in vitro diagnostic reagents conducted by medical laboratory have been increasing day by day. However, there are currently few discussions on the clinical trial of in vitro diagnostic reagents from the perspective of researchers. Therefore, this article summarizes the characteristics of clinical trials of in vitro diagnostic reagents, analyzes the problems and difficulties in conducting clinical trials of in vitro diagnostic reagents in current medical laboratories, and introduces the laboratory′s experience in management; to provide reference for medical testing laboratories that have not yet conducted or have already conducted clinical trials of in vitro diagnostic reagents, in order to improve the quality and efficiency of clinical trials.

Objective To investigate the basic information of human immunodeficiency virus/acquired immune deficiency syndrome(HIV/AIDS)patients who infected with Epstein-Barr virus(EBV)or human Cytomegalovirus(HCMV),collect the relevant clinical immunological data and analyze the influencing factors.Method A total of 1 093 HIV/AIDS patients treated in the First Hospital of Changsha from January to December 2022 and underwent EBV and HCMV screening were collected.Flow cytometry was used to detect the CD4+T lymphocytes.Fluorescence quantitative PCR was applied for HIV-RNA,EBV-DNA,and HCMV-DNA testing.Statistical analysis was carried out by using SPSS 27.0,and logistic regression was used to analyze the risk factors of HIV/AIDS patients complicated with viral infection.Results Among 1 093 HIV/AIDS patients,the positive rates of EBV-DNA and HCMV-DNA were 48.22%(527/1 093)and 19.03%(208/1 093),respectively.As the number of CD4+T lymphocytes increased,the positive rates of EBV-DNA and HCMV-DNA decreased,and the differences was statistically significant(χ2=39.50,143.0,all P<0.001).As the level of HIV-RNA increased,the positive rates of EBV-DNA and HCMV-DNA increased,and the differences were statistically significant(χ2=46.18,124.3,all P<0.001).The patients receiving antiretroviral therapy(ART)significantly decreased the positive rates of EBV-DNA and HCMV-DNA(χ2=30.60,96.59,all P<0.001).There was a significant negative correlation between the number of CD4+T lymphocytes and the level of HIV-RNA(r=-0.49,P<0.001).Logistic regression analysis showed that the CD4+T lymphocyte count<200/μl(OR=1.46,95%CI:1.02～2.08,P=0.037),HIV-RNA load>200 copies/ml(OR=1.70,95%CI:1.18～2.44,P=0.004)and the age>30 years old(OR=2.15,95%CI:1.44～3.19,P<0.001)were risk factors for HIV/AIDS patients infected with EBV.Without regularly receiving ART(OR=1.83,95%CI:1.10～3.02,P=0.019),HIV-RNA load>200 copies/ml(OR=2.56,95%CI:1.50～4.35,P<0.001)and the CD4+T lymphocyte count<200/μl(OR=4.61,95%CI:2.57～8.28,P<0.001)were risk factors for HCMV infection in HIV/AIDS patients.Conclusion To reduce the possibility of opportunistic infection in HIV/AIDS patients,the surveillance of EBV and HCMV and regular ART should be strengthened,especially when the number of CD4+T lymphocytes decreases(<200/μl),the level of HIV RNA increases(>200 copies/ml)or the age>30 years old.

Objective:High-throughput screening to obtain small molecular compounds against Gram-negative bacilli by targeting BamA outer membrane protein.Methods:The sybyl-X2.1 software was used to perform high-throughput virtual screening of small molecular compounds in Chemdiv compound library based on the molecular docking. The top 150 hits by high-throughput screening were re-screened through in vitro biological experiments. The top 4 small molecules with obvious antibacterial activity were selected for in-depth molecular docking analysis, and the small molecule 8308-0401 with the highest docking score was selected for further experiments. The antibacterial effect of 8308-0401 combined with rifampicin was tested by checkerboard assay. Finally, the affinity between 8308-0401 and BamA was tested by plasma surface resonance assay. Results:The docking score of the top 150 hits calculated by high-throughput virtual screening had a mean value of 5.63. In vitro biological experiments showed that small molecules 8308-0401, 8365-1335, C066-2507 and L582-0346 exhibited strong antibacterial activity. Among those molecules, 8308-0401 showed the highest molecular docking score, and synergistic antibacterial activity against both types of strains and clinical isolates when combined with rifampicin. 8308-0401 has a strong affinity to BamA with binding a constant of 182 μmol/L. Conclusion:The small molecule 8308-0401 exerts antibacterial activity against Gram negative bacilli by targeting the outer membrane protein BamA.

Objective:To investigate the clinical characteristics and possible causes of transient spontaneous remission of childhood acute leukemia.Methods:The data of 3 children with acute leukemia who had transient spontaneous remission before standardized chemotherapy in Sun Yat-sen Memorial Hospital of Sun Yat-sen University in July 2018, May 2019 and October 2020 were collected. Moreover, the related influencing factors of spontaneous remission in leukemia were discussed by review of the literature.Results:All 3 children had fever at the onset of the disease, and they achieved transient spontaneous remission after anti-infection therapy. Case 1 obtained partial remission after the initial diagnosis of acute B lymphocytic leukemia (B-ALL), leukemia gene test showed E2A-PBX1 fusion, and relapsed after 12 days. Case 2 obtained spontaneous remission after the initial diagnosis of B-ALL, leukemia gene test showed p16 gene deletion and NRAS and EP300 genes mutation, and relapsed after 20 days. Case 3 obtained spontaneous remission after the initial diagnosis of acute monocytic leukemia, leukemia gene test showed MLL-ENL fusion and NRAS gene mutation, and relapsed after 30 days. A review of the literature showed that the main influencing factors of spontaneous remission in leukemia were Down syndrome, infection and blood transfusion. Other influencing factors included leukemia-related genes, termination of pregnancy and application of drugs.Conclusions:Transient spontaneous remission of childhood acute leukemia is rare in clinical practice, and the possible mechanism is related to infection-induced immune abnormalities. It is recommended that leukemia patients with spontaneous remission should be closely monitored for minimal residual disease.

Objective:To analyze the clinical effect of hyaluronidase injection through the facial artery in the treatment of vascular embolism such as skin ulceration and necrosis after cosmetic injection.Methods:Hyaluronidase was injected through facial artery in 13 patients who were diagnosed with vascular embolism after facial injection from January 2019 to May 2020. The facial artery was punctured with 22-gauge arterial blood collection needle or 19/23-gauge disposable venous infusion needle. The angle between the needle body and the skin varies depending on the patients’ weight, ranged 30°-45°. The needle was advanced slowly and pushed forward by 2-3 mm when blood backflow appeared in the needle core. After confirming the successful puncture of the facial artery, 0.5-1.5 ml hyaluronidase was slowly injected into the facial artery. The time of skin relaxation, tenderness relief, ulcer healing and wound recovery were observed. The pigmentation was observed and the Vancouver Scar Scale (VSS) was used to score the scars after 3-12 months.Results:A toal of 13 patients with vascular complications of hyaluronidase filler were retrospectively reviewed. The patients were 18-45-year-old(mean age, 35 years) and received hyaluronidase filler at private clinics. There were 12 women and 1 man. The time from onset to visit was 14 h to 4 d, with an average time of 2.5 d. Hyaluronidase was most commonly injected into the nasolabial folds (54%, 7 of 13). The second-ranked area is the nasalroot (23%, 3 of 13). These patients had skin swelling, necrosis, ecchymosis or black scabs during or after hyaluronidase injection. Some patients showed skin lesions combined with oral ulcer. After percutaneous facial arterial hyaluronidase injection, the local skin tissue injuries of the 13 patients were improved in time. The time of skin relaxation was (0.77±0.25) d, the time of tenderness relief was (1.23±0.64) d, the time of ulcer healing was (3.14±0.64) d and the time of wound recovery was (5.85±0.86) d. Patients were followed up for 3-12 months, with an average of 7 months. One patient had slight scar (VSS score of 1), two patients had only mild pigmentation (VSS score of 0), and the other ten patients had no scar and pigmentation (VSS score of 0).Conclusions:It is effective to improve local microcirculation and reduce skin tissue injury after percutaneous facial artery hyaluronidase injection in the treatment of skin injury caused by facial filler injection.