ObjectiveTo understand the seropositivity of neutralizing antibodies (NAb) and low-level NAb against SARS-CoV-2 infection in the community residents, and to explore the impact of COVID-19 vaccination and SARS-CoV-2 infection on the levels of NAb in human serum. MethodsOn the ground of surveillance cohort for acute infectious diseases in community populations in Shanghai, a proportional stratified sampling method was used to enroll the subjects at a 20% proportion for each age group (0‒14, 15‒24, 25‒59, and ≥60 years old). Blood samples collection and serum SARS-CoV-2 NAb concentration testing were conducted from March to April 2023. Low-level NAb were defined as below the 25^th percentile of NAb. ResultsA total of 2 230 participants were included, the positive rate of NAb was 97.58%, and the proportion of low-level NAb was 25.02% (558/2 230). Multivariate logistic regression analysis indicated that age, infection history and vaccination status were correlated with low-level NAb (all P<0.05). Individuals aged 60 years and above had the highest risk of low-level NAb. There was a statistically significant interaction between booster vaccination and one single infection (aOR=0.38, 95%CI: 0.19‒0.77). Compared to individuals without vaccination, among individuals infected with SARS-CoV-2 once, both primary immunization (aOR=0.23, 95%CI: 0.16‒0.35) and booster immunization (aOR=0.12, 95%CI: 0.08‒0.17) significantly reduced the risk of low-level NAb; among individuals without infections, only booster immunization (aOR=0.28, 95%CI: 0.14‒0.52) showed a negative correlation with the risk of low-level NAb. ConclusionsThe population aged 60 and above had the highest risk of low-level NAb. Regardless of infection history, a booster immunization could reduce the risk of low-level NAb. It is recommended that eligible individuals , especially the elderly, should get vaccinated in a timely manner to exert the protective role of NAb.

Objective·To observe the effects of gingipain extract on the biological characteristics of oral squamous cell carcinoma cell HN6.Methods·The HN6 cell line was selected,cultivated,and divided into different groups based on the protein concentration of gingipain extract from Porphyromonas gingivalis:control group,3.125 μg/mL group,6.25 μg/mL group,12.5 μg/mL group,25 μg/mL group,50 μg/mL group,and 100 μg/mL group.After 24 and 48 h of cultivation,CCK-8 assay was used to detect the effects of gingipain extract on HN6 cell proliferation activity.Subsequent experiments were divided into control group,25 μg/mL group and 50 μg/mL group.Flow cytometry was used to examine the effects of gingipain extract on cell cycle.Scratch assay and Transwell assay were performed to evaluate cell migration and invasion ability.Real-time PCR(RT-PCR)and Western blotting were used to measure the expression of E-cadherin and N-cadherin proteins and genes in cells.Results·Stimulated with gingipain extract for 24 h,the HN6 cells showed significantly increased proliferation activity in the 25 μg/mL(P=0.025),50 μg/mL(P=0.000),and 100 μg/mL(P=0.049)groups compared to the control group.After 48 h,proliferation activity was significantly higher in the 6.25 μg/mL(P=0.024),12.5 μg/mL(P=0.006),25 μg/mL(P=0.000),50 μg/mL(P=0.000),and 100 μg/mL(P=0.000)groups compared to the control group.Cell cycle analysis revealed that,after 24 h of gingipain stimulation,the proportion of HN6 cells in the G1 phase decreased,while the proportion in the S+G2 phase significantly increased compared to the control group(25 μg/mL group:P=0.024;50 μg/mL group:P=0.001).Compared to the control group,the scratch assay demonstrated a significant increase in the percentage of scratch closure as the concentration of gingipain extract increased(P=0.001).Compared to the control group,the Transwell invasion assay showed a significant increase in the number of cells passing through the bottom of the chamber as the concentration of gingipain extract increased.RT-PCR and Western blotting results indicated that as the concentration of gingipain extract increased,the expression levels of N-cadherin mRNA and protein in HN6 cells significantly increased,while the expression levels of E-cadherin mRNA and protein significantly decreased compared to the control group.Conclusion·Gingipain extract could promote proliferation,migration,and invasion of oral squamous cell carcinoma HN6 cells.

Objective To clarify the influencing factors of defensive medicine and provide ideas for preventing and re-solving defensive medicine.Methods Literature related to defensive medicine was searched,personnel related to de-fensive medicine were interviewed,and literature and interview data were coded with the method of grounded theo-ry,and related concepts and categories were summarized.Results After three levels of coding,52 initial concepts,23 initial categories,7 sub-categories and 3 main categories were sorted out,and the correlation among influencing factors was analyzed to build a three-dimensional model of"doctor-patient relationship-institutional system-social environment"influencing factors and their mechanism of action.Conclusion The influencing factors of defensive medi-cine mainly include doctor-patient relationship,institutional system and social environment.The three factors have an impact on defensive medicine through different mechanisms of action,which provides qualitative evidence for comprehensive analysis of factors in related studies of defensive medicine.

Objective By exploring the conditional configuration effect of negative defensive medicine behavior,the formation mechanism and causal path of negative defensive medicine are explained,and systematic suggestions are provided for negative defensive medicine behavior,so as to improve the rational utilization of health resources.Methods NCA and fsQCA are used to conduct configuration analysis on factors influencing passive defensive medical behavior,output the conditional configuration,and further analyze the configuration effects among the influencing factors.Results The antecedent conditions of negative defensive medicine include systemic mechanisms,institutional norms,social culture,doctor-patient relationships,and self-efficacy.Ultimately,two paths contributing to passive defensive medical behavior emerge:environment conduction type and efficiency-environment joint conduction type,their consistency is 0.830.Conclusion To reduce the negative defensive medical behavior,it should pay atten-tion to improving the institutional environment and improving doctors'self-efficacy,establish a fair and reasonable external institutional environment,create an honest and harmonious cultural atmosphere,strengthen the training of doctors'professional ability and improve the doctor-patient relationship,so as to improve the rational use of health resources.

Objective To clarify the influencing factors of defensive medicine and provide ideas for preventing and re-solving defensive medicine.Methods Literature related to defensive medicine was searched,personnel related to de-fensive medicine were interviewed,and literature and interview data were coded with the method of grounded theo-ry,and related concepts and categories were summarized.Results After three levels of coding,52 initial concepts,23 initial categories,7 sub-categories and 3 main categories were sorted out,and the correlation among influencing factors was analyzed to build a three-dimensional model of"doctor-patient relationship-institutional system-social environment"influencing factors and their mechanism of action.Conclusion The influencing factors of defensive medi-cine mainly include doctor-patient relationship,institutional system and social environment.The three factors have an impact on defensive medicine through different mechanisms of action,which provides qualitative evidence for comprehensive analysis of factors in related studies of defensive medicine.

Objective By exploring the conditional configuration effect of negative defensive medicine behavior,the formation mechanism and causal path of negative defensive medicine are explained,and systematic suggestions are provided for negative defensive medicine behavior,so as to improve the rational utilization of health resources.Methods NCA and fsQCA are used to conduct configuration analysis on factors influencing passive defensive medical behavior,output the conditional configuration,and further analyze the configuration effects among the influencing factors.Results The antecedent conditions of negative defensive medicine include systemic mechanisms,institutional norms,social culture,doctor-patient relationships,and self-efficacy.Ultimately,two paths contributing to passive defensive medical behavior emerge:environment conduction type and efficiency-environment joint conduction type,their consistency is 0.830.Conclusion To reduce the negative defensive medical behavior,it should pay atten-tion to improving the institutional environment and improving doctors'self-efficacy,establish a fair and reasonable external institutional environment,create an honest and harmonious cultural atmosphere,strengthen the training of doctors'professional ability and improve the doctor-patient relationship,so as to improve the rational use of health resources.

Objective To clarify the influencing factors of defensive medicine and provide ideas for preventing and re-solving defensive medicine.Methods Literature related to defensive medicine was searched,personnel related to de-fensive medicine were interviewed,and literature and interview data were coded with the method of grounded theo-ry,and related concepts and categories were summarized.Results After three levels of coding,52 initial concepts,23 initial categories,7 sub-categories and 3 main categories were sorted out,and the correlation among influencing factors was analyzed to build a three-dimensional model of"doctor-patient relationship-institutional system-social environment"influencing factors and their mechanism of action.Conclusion The influencing factors of defensive medi-cine mainly include doctor-patient relationship,institutional system and social environment.The three factors have an impact on defensive medicine through different mechanisms of action,which provides qualitative evidence for comprehensive analysis of factors in related studies of defensive medicine.

Objective By exploring the conditional configuration effect of negative defensive medicine behavior,the formation mechanism and causal path of negative defensive medicine are explained,and systematic suggestions are provided for negative defensive medicine behavior,so as to improve the rational utilization of health resources.Methods NCA and fsQCA are used to conduct configuration analysis on factors influencing passive defensive medical behavior,output the conditional configuration,and further analyze the configuration effects among the influencing factors.Results The antecedent conditions of negative defensive medicine include systemic mechanisms,institutional norms,social culture,doctor-patient relationships,and self-efficacy.Ultimately,two paths contributing to passive defensive medical behavior emerge:environment conduction type and efficiency-environment joint conduction type,their consistency is 0.830.Conclusion To reduce the negative defensive medical behavior,it should pay atten-tion to improving the institutional environment and improving doctors'self-efficacy,establish a fair and reasonable external institutional environment,create an honest and harmonious cultural atmosphere,strengthen the training of doctors'professional ability and improve the doctor-patient relationship,so as to improve the rational use of health resources.

Objective To clarify the influencing factors of defensive medicine and provide ideas for preventing and re-solving defensive medicine.Methods Literature related to defensive medicine was searched,personnel related to de-fensive medicine were interviewed,and literature and interview data were coded with the method of grounded theo-ry,and related concepts and categories were summarized.Results After three levels of coding,52 initial concepts,23 initial categories,7 sub-categories and 3 main categories were sorted out,and the correlation among influencing factors was analyzed to build a three-dimensional model of"doctor-patient relationship-institutional system-social environment"influencing factors and their mechanism of action.Conclusion The influencing factors of defensive medi-cine mainly include doctor-patient relationship,institutional system and social environment.The three factors have an impact on defensive medicine through different mechanisms of action,which provides qualitative evidence for comprehensive analysis of factors in related studies of defensive medicine.

Objective By exploring the conditional configuration effect of negative defensive medicine behavior,the formation mechanism and causal path of negative defensive medicine are explained,and systematic suggestions are provided for negative defensive medicine behavior,so as to improve the rational utilization of health resources.Methods NCA and fsQCA are used to conduct configuration analysis on factors influencing passive defensive medical behavior,output the conditional configuration,and further analyze the configuration effects among the influencing factors.Results The antecedent conditions of negative defensive medicine include systemic mechanisms,institutional norms,social culture,doctor-patient relationships,and self-efficacy.Ultimately,two paths contributing to passive defensive medical behavior emerge:environment conduction type and efficiency-environment joint conduction type,their consistency is 0.830.Conclusion To reduce the negative defensive medical behavior,it should pay atten-tion to improving the institutional environment and improving doctors'self-efficacy,establish a fair and reasonable external institutional environment,create an honest and harmonious cultural atmosphere,strengthen the training of doctors'professional ability and improve the doctor-patient relationship,so as to improve the rational use of health resources.