Objective:This study aimed to explore the molecular mechanisms of the maladaptation of H3N2 influenza virus in chicken embryos, provide a theoretical basis for the restoration of H3N2 influenza vaccine production in chicken embryos.Methods:Samples of respiratory secretions from patients with influenza-like symptoms (Influenza-like Illness, ILI) caused by H3N2 influenza virus were inoculated into chicken embryos and Madin-Darby Canine Kidney cells (MDCK), respectively. After isolating the virus, hemagglutination experiments were conducted to detect hemagglutination titers and hemagglutination inhibition experiments were used to compare antigenic differences; further, whole-genome sequencing of H3N2 influenza virus was performed using second-generation high-throughput gene sequencing (Next Generation High-Throughput Gene Sequencing, NGS), and key amino acid sites of mutations were identified through sequence alignment; combined with sialic acid receptor binding experiments, the differences in the binding of wild-type and mutant receptor binding sites (RBS) to sialic acid receptors were compared; finally, molecular docking and molecular dynamics simulation method were used to explore the specific molecular mechanisms of how mutation sites affect the differences in the affinity of the RBS pocket for sialic acid receptors.Results:The hemagglutination assay result indicated that both chicken embryos and MDCK cells could isolate the influenza virus, and the hemagglutination inhibition test showed that no antigenic differences were produced in the isolated strains. NGS analysis revealed that the H3N2 virus underwent an F195Y mutation in the (RBS) region of the hemagglutinin (HA) protein after adaptation through chicken embryo passages. Receptor-binding experiments demonstrated that the F195Y mutation enhanced the virus′s binding ability to α2, 3-linked sialic acid glycan (Neu5Acα2-3Galβ1-4GlcNAcβ-PAA, 3′SLN), while the mutation did not affect the affinity of the RBS pocket for α2, 6-linked sialic acid glycan (Neu5Acα2-6Galβ1-4GlcNAcβ-PAA, 6′SLN). Molecular docking and molecular dynamics simulation result indicate that the F195Y mutation, by replacing a hydrophobic amino acid with a hydrophilic one, leads to a significant decrease in the structure of the RBS pocket, enhancing the binding stability of the H3N2 influenza virus with α2, 3-sln. This is specifically manifested by an increase in binding time and an increase in the number of hydrogen bonds at the RBS site with the receptor. Furthermore, the F195Y mutation does not alter the binding of the virus to other receptors.Conclusions:The F195Y mutation in the RBS pocket of H3N2 influenza virus is a key site affecting the viral chicken embryo inadaptability.

Objective:This study aimed to explore the molecular mechanisms of the maladaptation of H3N2 influenza virus in chicken embryos, provide a theoretical basis for the restoration of H3N2 influenza vaccine production in chicken embryos.Methods:Samples of respiratory secretions from patients with influenza-like symptoms (Influenza-like Illness, ILI) caused by H3N2 influenza virus were inoculated into chicken embryos and Madin-Darby Canine Kidney cells (MDCK), respectively. After isolating the virus, hemagglutination experiments were conducted to detect hemagglutination titers and hemagglutination inhibition experiments were used to compare antigenic differences; further, whole-genome sequencing of H3N2 influenza virus was performed using second-generation high-throughput gene sequencing (Next Generation High-Throughput Gene Sequencing, NGS), and key amino acid sites of mutations were identified through sequence alignment; combined with sialic acid receptor binding experiments, the differences in the binding of wild-type and mutant receptor binding sites (RBS) to sialic acid receptors were compared; finally, molecular docking and molecular dynamics simulation method were used to explore the specific molecular mechanisms of how mutation sites affect the differences in the affinity of the RBS pocket for sialic acid receptors.Results:The hemagglutination assay result indicated that both chicken embryos and MDCK cells could isolate the influenza virus, and the hemagglutination inhibition test showed that no antigenic differences were produced in the isolated strains. NGS analysis revealed that the H3N2 virus underwent an F195Y mutation in the (RBS) region of the hemagglutinin (HA) protein after adaptation through chicken embryo passages. Receptor-binding experiments demonstrated that the F195Y mutation enhanced the virus′s binding ability to α2, 3-linked sialic acid glycan (Neu5Acα2-3Galβ1-4GlcNAcβ-PAA, 3′SLN), while the mutation did not affect the affinity of the RBS pocket for α2, 6-linked sialic acid glycan (Neu5Acα2-6Galβ1-4GlcNAcβ-PAA, 6′SLN). Molecular docking and molecular dynamics simulation result indicate that the F195Y mutation, by replacing a hydrophobic amino acid with a hydrophilic one, leads to a significant decrease in the structure of the RBS pocket, enhancing the binding stability of the H3N2 influenza virus with α2, 3-sln. This is specifically manifested by an increase in binding time and an increase in the number of hydrogen bonds at the RBS site with the receptor. Furthermore, the F195Y mutation does not alter the binding of the virus to other receptors.Conclusions:The F195Y mutation in the RBS pocket of H3N2 influenza virus is a key site affecting the viral chicken embryo inadaptability.

Objective:To explore the clinical effect of azacitidine combined with CAG regimen on the treatment of relapsed/refractory acute myeloid leukemia (AML).Methods:The data of 50 patients with relapsed/refractory AML (non-acute promyelocytic leukemia) in Jining No. 1 People's Hospital from September 2018 to September 2019 was retrospectively analyzed, and the patients were divided into the control group and the test group according to the different treatment drugs. The control group (28 cases) was treated with CAG regimen alone, and the test group (22 cases) was treated with azacitidine combined with CAG regimen. The total effective rate and adverse reactions of the two groups were observed after 1 course of treatment.Results:After one course of treatment, the total clinical effective rate in the test group was 86% (19/22), and the rate in the control group was 71% (20/28), there was a statistically significant difference between the two groups (χ 2 = 5.273, P < 0.05). There were no significant differences in the incidence of adverse reactions such as fever, pulmonary infection, vomiting, and thrombocytopenia between the two groups (all P > 0.05). Conclusion:Azacitidine combined with CAG regimen in the treatment of relapsed/refractory AML can improve the clinical efficacy without increasing the adverse reactions.

Objective:To explore the clinical characteristics and establish a corresponding prognostic scoring model in patients with early-stage clinical features of hepatitis B-induced acute-on-chronic liver failure (HBV-ACLF).Methods:Clinical characteristics of 725 cases with hepatitis B-related acute-on-chronic hepatic dysfunction (HBV-ACHD) were retrospectively analyzed using Chinese group on the study of severe hepatitis B (COSSH). The independent risk factors associated with 90-day prognosis to establish a prognostic scoring model was analyzed by multivariate Cox regression, and was validated by 500 internal and 390 external HBV-ACHD patients.Results:Among 725 cases with HBV-ACHD, 76.8% were male, 96.8% had cirrhosis base,66.5% had complications of ascites, 4.1% had coagulation failure in respect to organ failure, and 9.2% had 90-day mortality rate. Multivariate Cox regression analysis showed that TBil, WBC and ALP were the best predictors of 90-day mortality rate in HBV-ACHD patients. The established scoring model was COSS-HACHADs = 0.75 × ln(WBC) + 0.57 × ln(TBil)-0.94 × ln(ALP) +10. The area under the receiver operating characteristic curve (AUROC) of subjects was significantly higher than MELD, MELD-Na, CTP and CLIF-C ADs( P < 0.05). An analysis of 500 and 390 cases of internal random selection group and external group had similar verified results. Conclusion:HBV-ACHD patients are a group of people with decompensated cirrhosis combined with small number of organ failure, and the 90-day mortality rate is 9.2%. COSSH-ACHDs have a higher predictive effect on HBV-ACHD patients' 90-day prognosis, and thus provide evidence-based medicine for early clinical diagnosis and treatment.

Objective To understand the direct economic burden of healthcare-associated infection(HAI)due to multidrug-resistant organisms(MDROs).Methods Computer retrieval of CNKI,Wanfang,VIP,PubMed,Sci-enceDirect,and Cochrane databases on literatures about economic burden of MDRO HAI at home and abroad were performed,the retrieval time was from database establishment to December 2015,systematic evaluation of the liter-atures was obtained.Results According to the inclusion and exclusion criteria,as well as through Newcastle-Otta-wa Scale (NOS)for evaluating the literatures,19 literatures were included.In 12 studies about methicillin-resistant Staphylococcusaureus infection,the direct economic cost varied from $916.61 to $62908.00;in 4 studies about MDRO Acinetobacterbaumannii infection,the direct economic cost varied from$4644.00 to $98575.00.Direct economic cost due to extended-spectrumβ-lactamases-producing Enterobacteriaceae was $2824.14-$30093.00. Conclusion MDRO HAI will increase economic cost of both hospitals and patients,prevention and control measures should be taken .

Objective To investigate the value of hs-CRP in the assessment of risk stratification,coronary artery disease severity and prognosis for patients undergoing PCI with coronary heart disease.Methods A total of 150 coronary heart disease patients were recruited in the study,who had undergone PCI,and before that all the patients had undergone coronary angiography,and the levels of hs-CRP,TG,LDL-C,HDL-C,NT-proBNP and hs-cTnT were measured.Patients were divided into three groups according to the serum concentration of hs-CRP.Gemini score was used to determine the degree of stenosis.After PCI,patients were followed up for 6 months,the major cardiovascular events(MACE)were recorded.The relationships between hs-CRP and other coronary risk factors,Gemini score,vasculopathy count,MACE events were analyzed.Results The serum concentrations of hs-CRP and HDL-C, hs-cTnT were significantly correlated(r=-0.17,0.42,P <0.05).The level of hs-CRP had increasing tendency with the increase of Gensini score,and the serum concentration of hs-CRP in severe vascular lesions group was significantly higher than both mild vascular lesions group and moderate vascular lesions group(P <0.05).The serum concentration of hs-CRP in single-vessel disease patients,double-vessel disease patients and multi-vessel disease patients were (4.64±5.39),(9.86±8.75),(14.93±10.34)mg/L, there was significant difference among them(P <0.05 ).The correlation coefficients of hs-CRP and Gemini score was 0.21 (P <0.05),while hs-CRP and vasculopathy count was 0.18(P <0.05).The incidence of MACE in three groups were 18.52%,43.75%and 58.66%,which were statistically significantly difference(χ2 =13.42,P =0.001).Logistic regression showed that hs-CRP was an independent risk factor for MACE(OR =2.05,95%CI :1.24 -3.39,P =0.005).Conclusion Hs-CRP is an independent risk factor for coronary heart disease in patients with MACE after PCI,and hs-CRP was correlated with PCI patient′s vascular disease. Hs-CRP can be used as an indicator in the assessment of patient′s condition,PCI risk stratification and prognosis.

OBJECTIVETo study the in vitro antibacterial activity of meropenem combined with doxycycline, ciprofloxacin, sulbactam or cefoperazone/sulbactam against clinically isolated extensively drug-resistant Acinetobacter baumannii (XDRAB).

METHODSUsing a checker board synergy design, the minimal inhibitory concentration (MIC) of antibiotics against 50 isolates of XDRAB was determined by broth microdilution antifungal susceptibility test. The fractional inhibitory concentration (FIC) index was calculated to determine the combined effect of the antibiotics.

RESULTSMeropenem showed significantly reduced MIC50 and enhanced antimicrobial activities when combined with doxycycline, sulbactam or cefoperazone/sulbactam. The FIC results suggested that the main actions of doxycycline, sulbactam, and cefoperazone/sulbactam were synergistic (38%, 26%, and 10%, respectively) and addictive (62%, 74%, and 90%, respectively) without indifferent or antagonistic effects. The main actions of meropenem combined with ciprofloxacin were additive (56%) and indifference (44%) with synergistic and antagonistic effects.

CONCLUSIONMeropenem combined with doxycycline, sulbactam or cefoperazone/sulbactam shows excellent activity against clinical isolates of XDRAB.

Acinetobacter baumannii ; drug effects ; Anti-Bacterial Agents ; pharmacology ; Drug Combinations ; Drug Synergism ; Microbial Sensitivity Tests ; Thienamycins ; pharmacology

Objective To study the in vitro antibacterial activity of meropenem combined with doxycycline, ciprofloxacin, sulbactam or cefoperazone/sulbactam against clinically isolated extensively drug-resistant Acinetobacter baumannii (XDRAB). Methods Using a checker board synergy design, the minimal inhibitory concentration (MIC) of antibiotics against 50 isolates of XDRAB was determined by broth microdilution antifungal susceptibility test. The fractional inhibitory concentration (FIC) index was calculated to determine the combined effect of the antibiotics. Results Meropenem showed significantly reduced MIC50 and enhanced antimicrobial activities when combined with doxycycline, sulbactam or cefoperazone/sulbactam. The FIC results suggested that the main actions of doxycycline, sulbactam, and cefoperazone/sulbactam were synergistic (38%, 26%, and 10%, respectively) and addictive (62%, 74%, and 90%, respectively) without indifferent or antagonistic effects. The main actions of meropenem combined with ciprofloxacin were additive (56%) and indifference (44%) with synergistic and antagonistic effects. Conclusion Meropenem combined with doxycycline, sulbactam or cefoperazone/sulbactam shows excellent activity against clinical isolates of XDRAB.

Objective To study the in vitro antibacterial activity of meropenem combined with doxycycline, ciprofloxacin, sulbactam or cefoperazone/sulbactam against clinically isolated extensively drug-resistant Acinetobacter baumannii (XDRAB). Methods Using a checker board synergy design, the minimal inhibitory concentration (MIC) of antibiotics against 50 isolates of XDRAB was determined by broth microdilution antifungal susceptibility test. The fractional inhibitory concentration (FIC) index was calculated to determine the combined effect of the antibiotics. Results Meropenem showed significantly reduced MIC50 and enhanced antimicrobial activities when combined with doxycycline, sulbactam or cefoperazone/sulbactam. The FIC results suggested that the main actions of doxycycline, sulbactam, and cefoperazone/sulbactam were synergistic (38%, 26%, and 10%, respectively) and addictive (62%, 74%, and 90%, respectively) without indifferent or antagonistic effects. The main actions of meropenem combined with ciprofloxacin were additive (56%) and indifference (44%) with synergistic and antagonistic effects. Conclusion Meropenem combined with doxycycline, sulbactam or cefoperazone/sulbactam shows excellent activity against clinical isolates of XDRAB.

OBJECTIVETo evaluate the sensitivity and specificity of nested PCR combined with pyrosequencing in the detection of HBV drug-resistance gene.

METHODSRtM204I (ATT) mutant and rtM204 (ATG) nonmutant plasmids mixed at different ratios were detected for mutations using nested-PCR combined with pyrosequencing, and the results were compared with those by conventional PCR pyrosequencing to analyze the linearity and consistency of the two methods. Clinical specimens with different viral loads were examined for drug-resistant mutations using nested PCR pyrosequencing and nested PCR combined with dideoxy sequencing (Sanger) for comparison of the detection sensitivity and specificity.

RESULTSThe fitting curves demonstrated good linearity of both conventional PCR pyrosequencing and nested PCR pyrosequencing (R(2)>0.99, P<0.05). Nested PCR showed a better consistency with the predicted value than conventional PCR, and was superior to conventional PCR for detection of samples containing 90% mutant plasmid. In the detection of clinical specimens, Sanger sequencing had a significantly lower sensitivity than nested PCR pyrosequencing (92% vs 100%, P<0.01). The detection sensitivity of Sanger sequencing varied with the viral loads, especially in samples with low viral copies (HBV DNA ≤3log10 copies/ml), where the sensitivity was 78%, significantly lower than that of pyrosequencing (100%, P<0.01). Neither of the two methods yielded positive results for the negative control samples, suggesting their good specificity.

CONCLUSIONCompared with nested PCR and Sanger sequencing method, nested PCR pyrosequencing has a higher sensitivity especially in clinical specimens with low viral copies, which can be important for early detection of HBV mutant strains and hence more effective clinical management.

Adolescent ; Adult ; Aged ; DNA, Viral ; genetics ; Drug Resistance, Viral ; genetics ; Female ; Hepatitis B virus ; drug effects ; genetics ; isolation & purification ; Humans ; Male ; Middle Aged ; Phosphoric Acids ; Plasmids ; Polymerase Chain Reaction ; Reagent Kits, Diagnostic ; Sensitivity and Specificity ; Young Adult