OBJECTIVE To evaluate the value of matrix-assisted laser desorption ionization time-of-flight-mass spectrometry(MALDI-TOF MS)in direct identification of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae positive for blood culture.METHODS The blood culture bottles that were positive for E.coli or K.pneumoniae were collected from the patients with bloodstream infection who were treated in Zhongshan Hospi-tal,Fudan University from Jul.2021 to Jun.2023.The isolates were collected by using a gel-contact clotting tube,then the tested strains were respectively mixed with 4 μg/ml of imipenem,4 μg/ml of meropenem and 2 μg/ml of ertapenem for coculture and were incubated at 35 ℃ for 4 and 5 hours,finally,the strains were i-dentified by using the mass spectrum.The minimum inhibitory concentrations(MICs)of the three types of drugs were tested by microbroth dilution method and were set as the golden standards for the test.RESULTS Totally 31 strains of E.coli and 28 strains of K.pneumoniae that were positive in blood culture bottles were collected,both of the effective rates of controlled growth of the E.coli strains were 100.00％after the incuba-tion for 4 and 5 hours,and the effective rates of controlled growth of the K.pneumoniae strains were 9 6.43％and 100.00％after the incubation for 4 and hours,respectively.The sensitivity,specificity,positive predictive value and negative predictive value of the K.pneumoniae strains against the three types of drugs were 100.00％after the incubation for 5 hours.The specificity and positive predictive value of the E.coli strains against imipenem,meropenem and ertapenem were 100.00％after the incubation for 5 hours;the sensitivities were 73.58％,78.93％and 78.93％,respectively;the negative predictive values were 70.60％,75.00％and 75.00％,respectively.CONCLUSIONS MALDI-TOF MS is rapid and accurate for direct identification of the carbapenem-resistant E.coli and K.pneumoniae strains positive in blood culture bottles,and the accuracy reaches at 100.00％for the test of drug-resistant K.pneumoniae strains after the incubation for 5 hours.The method may provide evidence for clinical treatment of bloodstream infections induced by carbapenem-resistant Enterobacteriaceae.

OBJECTIVE To evaluate the value of matrix-assisted laser desorption ionization time-of-flight-mass spectrometry(MALDI-TOF MS)in direct identification of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae positive for blood culture.METHODS The blood culture bottles that were positive for E.coli or K.pneumoniae were collected from the patients with bloodstream infection who were treated in Zhongshan Hospi-tal,Fudan University from Jul.2021 to Jun.2023.The isolates were collected by using a gel-contact clotting tube,then the tested strains were respectively mixed with 4 μg/ml of imipenem,4 μg/ml of meropenem and 2 μg/ml of ertapenem for coculture and were incubated at 35 ℃ for 4 and 5 hours,finally,the strains were i-dentified by using the mass spectrum.The minimum inhibitory concentrations(MICs)of the three types of drugs were tested by microbroth dilution method and were set as the golden standards for the test.RESULTS Totally 31 strains of E.coli and 28 strains of K.pneumoniae that were positive in blood culture bottles were collected,both of the effective rates of controlled growth of the E.coli strains were 100.00％after the incuba-tion for 4 and 5 hours,and the effective rates of controlled growth of the K.pneumoniae strains were 9 6.43％and 100.00％after the incubation for 4 and hours,respectively.The sensitivity,specificity,positive predictive value and negative predictive value of the K.pneumoniae strains against the three types of drugs were 100.00％after the incubation for 5 hours.The specificity and positive predictive value of the E.coli strains against imipenem,meropenem and ertapenem were 100.00％after the incubation for 5 hours;the sensitivities were 73.58％,78.93％and 78.93％,respectively;the negative predictive values were 70.60％,75.00％and 75.00％,respectively.CONCLUSIONS MALDI-TOF MS is rapid and accurate for direct identification of the carbapenem-resistant E.coli and K.pneumoniae strains positive in blood culture bottles,and the accuracy reaches at 100.00％for the test of drug-resistant K.pneumoniae strains after the incubation for 5 hours.The method may provide evidence for clinical treatment of bloodstream infections induced by carbapenem-resistant Enterobacteriaceae.

Objective To investigate the effect of overexpression of LncRNA MEG3 on proliferation,migration and cisplatin sensitivity of hepatoma cells HepG2 and LM3 and explore the underlying and mechanism.Methods The expression of MEG3 in healthy individuals and patients with hepatocellular carcinoma(HCC)was analyzed by online bioinformatics analysis,and Real-time fluorescence quantitative PCR(qRT-PCR)was used to detect MEG3 expression in different HCC cell lines.A MEG3-overexpresing plasmid was transfected in HepG2 and LM3 cells,and the changes in cell proliferation and migration were examined using CCK8 assay and scratch assay.CCK8 assay was used to determine the inhibitory rate of cisplatin on the transfected cells.A reactive oxygen species(ROS)fluorescence probe(DCFH-DA)and malondialdehyde(MDA)kit were used to assess the changes in ROS production and MDA level in the cells.Western blotting was performed to detect the expression levels of ferroptosis-related proteins glutathione peroxidase 4(GPX4)and ferritin heavy chain 1(FTH1).Results The expression of MEG3 was significantly lower in HCC cells than in LO2 cells,which was consistent with the results of bioinformatic analysis(P<0.05).Overexpression of MEG3 in the HCC cell lines significantly suppressed cell proliferation and migration(P<0.05),increased the cell inhibition rate of cisplatin(P<0.05),enhanced cellular ROS production and increased MDA levels in the cells(P<0.05).MEG3 overexpression significantly decreased the expressions of GPX4 and FTH1 in the HCC cell lines.Conclusion The expression of MEG3 is decreased in HCC cells,and its overexpression inhibits proliferation and migration and enhances cisplatin sensitivity of HCC cells by promoting ferroptosis of the cells.

Objective:To understand the molecular characteristics of the mutant strain of polymerase basic protein 2 (PB2) gene of influenza A (H1N1pdm) in Guangdong province, and to explore its specific molecular sites, so as to provide scientific basis for the prevention and control of influenza virus.Methods:Throat swab samples were collected from 2 cases infected with PB2 gene variant strains for virus isolation, and 23 influenza virus strains were selected from Guangdong province for sequencing analysis. The reference sequences and vaccine strain sequences provided by GISAID were used to perform evolutionary analysis on hemagglutinin (HA) and PB2 genes. Virus strain antigen analysis and neuraminidase (NA) inhibition test were carried out. PB2 protein model was constructed and polymerase activity was analyzed.Results:H399N amino acid mutation occurred in the HA gene of PB2-D701N and PB2-A271S variant strains, both of which belonged to the branch of 6B.1A.5a.2a. They belonged to the same big branch and different small branches as the vaccine strain A/Victoria/4897/2022, and they are all vaccine-like strains. In the three-dimensional structure, the mutations of PB2-D701N and PB2-A271S change charge and hydrophobicity.Conclusions:PB2-D701 and A271 were highly conserved, and PB2 mutant strains were not the dominant strains. The PB2 mutant had high antigenicity with the vaccine. The PB2 mutant strain is sensitive to NA inhibitors. The three-dimensional model predicted that PB2-D701N mutation could enhance virulence and affect transmissibility of influenza virus, while PB2-A271S mutation could affect polymerase activity and polymerase complex synthesis of influenza virus.

Objective To investigate the effect of overexpression of LncRNA MEG3 on proliferation,migration and cisplatin sensitivity of hepatoma cells HepG2 and LM3 and explore the underlying and mechanism.Methods The expression of MEG3 in healthy individuals and patients with hepatocellular carcinoma(HCC)was analyzed by online bioinformatics analysis,and Real-time fluorescence quantitative PCR(qRT-PCR)was used to detect MEG3 expression in different HCC cell lines.A MEG3-overexpresing plasmid was transfected in HepG2 and LM3 cells,and the changes in cell proliferation and migration were examined using CCK8 assay and scratch assay.CCK8 assay was used to determine the inhibitory rate of cisplatin on the transfected cells.A reactive oxygen species(ROS)fluorescence probe(DCFH-DA)and malondialdehyde(MDA)kit were used to assess the changes in ROS production and MDA level in the cells.Western blotting was performed to detect the expression levels of ferroptosis-related proteins glutathione peroxidase 4(GPX4)and ferritin heavy chain 1(FTH1).Results The expression of MEG3 was significantly lower in HCC cells than in LO2 cells,which was consistent with the results of bioinformatic analysis(P<0.05).Overexpression of MEG3 in the HCC cell lines significantly suppressed cell proliferation and migration(P<0.05),increased the cell inhibition rate of cisplatin(P<0.05),enhanced cellular ROS production and increased MDA levels in the cells(P<0.05).MEG3 overexpression significantly decreased the expressions of GPX4 and FTH1 in the HCC cell lines.Conclusion The expression of MEG3 is decreased in HCC cells,and its overexpression inhibits proliferation and migration and enhances cisplatin sensitivity of HCC cells by promoting ferroptosis of the cells.

Objective To investigate the correlation between serum miR-27b-3p and N-terminal propeptide of type Ⅰ procollagen (PINP) and C-terminal telopeptide of type Ⅰ collagen 1 (CTX-1) in postmenopausal women. Methods Forty-nine patients with postmenopausal osteoporosis treated in the Second Affiliated Hospital,Zhejiang Chinese Medical University from February 2022 to February 2023 were selected as study objects. They were divided into osteoporosis (OP) group (T≤-2.5SD,26 cases) and osteopenia (OPn) group (-2.5SD

Objective To investigate the correlation between serum miR-27b-3p and N-terminal propeptide of type Ⅰ procollagen (PINP) and C-terminal telopeptide of type Ⅰ collagen 1 (CTX-1) in postmenopausal women. Methods Forty-nine patients with postmenopausal osteoporosis treated in the Second Affiliated Hospital,Zhejiang Chinese Medical University from February 2022 to February 2023 were selected as study objects. They were divided into osteoporosis (OP) group (T≤-2.5SD,26 cases) and osteopenia (OPn) group (-2.5SD

OBJECTIVE: To investigate the effects of overexpression of long noncoding RNA (lncRNA) MEG3 on the proliferation and invasion of glioblastoma U251 cells by suppressing the expression of hypoxia inducible factor 1 METHODS: The expression of lncRNA MEG3 and HIF1 RESULTS: The expression of MEG3 was significantly lower and HIF1 CONCLUSIONS MEG3 overexpression inhibits the proliferation and invasion of U251 cells through suppressing the expression of HIF1
Apoptosis ; Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Gene Expression Regulation, Neoplastic ; Glioblastoma/genetics* ; Humans ; MicroRNAs ; RNA, Long Noncoding/genetics*

Objective:To understand the etiology of a confirmed case of Coronavirus Disease 2019 (COVID-19).Methods:The pharyngeal swabs, serum and nasal swabs of a case of COVID-19 were inoculated into Vero-E6 cell tubes for virus isolation. The cytopathic effect (CPE) were observed daily. Collecting cell’s isolation when CPE was over 75%, after repeated freezing and thawing for 3 times, the supernatant was centrifugally taken, and the images of the virus were obtained by transmission electron microscopic observation, and the nucleic acid of the virus was extracted, second generation sequencing and sequence evolution analysis were used to identify and type the virus strains.Results:One strain of 2019 novel coronavirus (2019-nCoV) was successfully isolated from the nasal swab of this case of COVID-19, and one strain of herpes simplex virus type 1 (HSV-1) was also successfully isolated from the throat swab of the same case.Conclusions:COVID-19 cases have the possibility of co-infection with 2019-nCoV and HSV-1.