OBJECTIVE To study the mechanisms of quinolones resistance in Escherichia coli.METHODS Forty E.coli clinical isolates were randomly collected from clinical specimens at the Tianjin First Central Hospital from Mar 2004 to Dec 2005.Then we detected the susceptibility to antibiotics in 40 clinical isolates of E.coli by MICs and K-B disk diffusion method.In order to investigate the mutations in the target genes,we amplified the QRDR of gyrA and parC by PCR.Later we analyzed the PCR products by single strand conformation polymorphism analysis(SSCP).In the meantime,the PCR products of marOR region were sequenced to detect the possible gene changes which contributed to the increasing expression of MarA and then lead to the Mar phenotype.RESULTS The alterations in gyrA were found in all quinolones-resistante strains.Asp87→Asn and Ala84→Pro were found besides the common amino acid alteration.The alterations in parC were found in thirty-six strains resistant to quinolones.There were no parC alterations in ECO24 which was nalidixic acid-resistant and ofloxacin/gatifloxacin-susceptible.ECO11 Which was resistant to quinolones only had no gene changes in marOR region.Six gene changes in marOR region were found in ECO5 which was resistant to mutiple antibodies.The alteration in 1879 bp changed the terminator.CONCLUSIONS The alterations in gyrA and parC are responsible for the resistant phenotypes in E.coli.That is,the alterations in the gyrA are primarily responsible for resistance to quinolones,and the alterations in the parC may play a complemental role in enhancing resistance to fluoroquinolones.Moreover,the randomly collected strains resistant to quinolones,have found some mutations in marOR.It may be play certain roles in multiple antibiotic resistance of E.coli.

Oxygen is a mandatory for all aerobic organisms. Oxygen-containing free radicals are produced when oxygen is not completely reduced to water in energy-producing oxidation reaction.The radicals may also transform into other reactive compounds through electron transfer and all the compounds with similar functions are referred as reactive oxygen species(ROS).Increased ROS is known to cause damage to proteins,DNA and lipids.Much evidence showed that changes in partial oxygen pressure,hormone,cytokine and chemical stimulation could increase ROS,and ROS,acting as signaling molecules,mediates cell functions.Hypoxia-inducing factor(HIF),a key transcriptional factor for most hypoxia-inducible genes,is a heterodimer consisting of 2 subunits.Recent study found that ROS plays an important role in HIF activity regulation under hypoxic and non-hypoxic conditions.This paper reviews the production of ROS and its role in the regulation of HIF activity.

BackgroundDue to the COVID-19 pandemic， both teenagers' studies and personal life are critically affected， which has resulted in a variety of mental health problems. In this regard， scholars at home and abroad have carried out a large number of research concerning adolescent mental health， of which there still exists a lack of systematic combing and review. ObjectiveTo understand the status and development trend of research on adolescent mental health during the COVID-19 pandemic at home and abroad， and to grasp the current research hotspots and trends in this field， so as to provide references for relevant research and practice in the post-epidemic era. MethodsOn October 30， 2022， we searched through China Knowledge Network Infrastructure （CNKI） and Web of Science database， and the publishing time of articles to be retrieved was limited between December 1， 2019 and October 30， 2022. Excel and CiteSpace were used to perform visual analysis on these articles in terms of number， author， institution， country and keywords of the articles. ResultsA total of 7 608 articles were included. At home and abroad， the number of papers related to adolescent mental health generally increased at first and then decreased under the pandemic situation. Compared with foreign countries， the connection and cooperation among domestic scholars and institutions was not close enough. The top three countries in the number of English literature published were the United States， Britain and China， and those in intermediary center were Tunis， Cameroon and Anguilla. The parent-child relationship and mental health of teenagers during were much concerned by scholars both at home and abroad. With the passage of time， researchers at home and abroad had shifted their focus from only negative factors to positive factors. ConclusionChinese scholars or institutions need to strengthen more domestic and international exchanges and cooperation. Scholars from different countries can carry out cross-cultural study on research topics of common concern， and continue to explore the positive psychological changes of teenagers in the post-epidemic era.［Funded by National Social Science Foundation 2020 Education Youth Project of 13th Five-Year Plan （number， CHA200259）］

Objective This report aims to assess the exposure risk of aflatoxin B1 in edible vegetable oil in Guangxi.Methods By using margin of exposure (MOE),the report analyzes the dietary exposure of aflatoxin B1 in edible vegetable oil with the data from contamination survey and dietary intake survey.Results For the vegetable oil sample,the content of aflatoxin B1 was between 0.50-320.00 μg/kg.The detection rate of peanut oil was 78.08％ (114/146) which was higher than other vegetable oil,and the exceeding rate was 31.51％ (46/146).For peanut oil,the average content was 30.80 μg/kg,the dietary exposure of the population was 17.30 ng/kg BW,and the MOE was 18.For the prepackaged peanut oil samples,the average content of aflatoxin B1 was 6.33 μg/kg,which was below the limit.While for the bulk peanut oil,the average content of AFB1 was 41.50 μg/kg,which was more than 1.08 times of the limit,and the dietary exposure was 25.59 ng/kg BW.The MOE of bulk peanut oil was 12,1/8 of the prepackaged peanut oil.Conclusion Food safety regulators should pay more attention to bulk peanut oil products,the priority in the risk management measures.At the same time,related department should also promote healthy education for the residents.

Objective: To analyze the ear, nose, and throat exam of some freshmen in the military college entrance examination in Shandong Province in 2020 and to facilitate adolescent targeted health promotion. Methods: The 1 411 freshmen participating in the military college entrance examination in Jinan, Zibo and Weifang of Shandong Province were included. The ear, nose, and throat exam were performed by professionals using electric otoscope, 5 meter whispering test, and front rhinoscope. Results: Nasal septal deviation and hypertrophy of inferior turbinate accounted for the highest proportion. Among 489 cases of nasal septum deviation, the detection rate of Jinan (15.97%) was significantly lower than that of Weifang (43.60%) and Zibo (46.53%) ( χ 2=63.32， P <0.05). For deviation of nasal septum, the detection rate in students with urban residence (31.53%) was significantly lower than that of rural students (39.03%) ( χ 2=4.11， P <0.05). Seventy two cases of inferior turbinate hyperplasia were detected, and the detection rate in Jinan (2.99%) was significantly lower than that in Weifang (6.51%) and Zibo (6.04%) ( χ 2=6.63， P <0.05). The detection rate of tonsil hypertrophy was significantly lower in boys (4.63%), students from urban area (3.94%), compared with that of girls(9.56%) and rural students (6.70%) ( χ 2=5.35，4.86， P <0.05). In pharyngeal examination, tonsil hyperplasia was the most common condition of enlarged tonsils ( n =214), which was significantly higher in Jinan(22.36%) than that of Weifang (11.71 %) and Zibo (10.74%) ( χ 2=22.39， P <0.05), and was significantly lower in boys (14.38%) and rural students (12.40%) than that in girls (22.79%) and urban students (17.24%) ( χ 2=4.70，4.65， P <0.05). Conclusion Nasal septum deviation and tonsil hypertrophy are the most prevalent upper airway diseases among freshmen participating in the military college entrance examination. Prevention and treatment of nasopharynx diseases should be emphasized.

Background Regional differences in economic development, natural environment, health care level, and social structure may lead to differences in the provincial distribution of the health status of the elderly population. Objective To explore the provincial distribution characteristics, regional differences, and influencing factors of the self-assessed health of the elderly population, with the aim of providing a policy basis for improving the health of the elderly population and promoting healthy aging according to local conditions. Methods Using 31 provinces (municipalities and autonomous regions) in China as the basicstudy unit and based on the method of Wagstaff, the self-rated health data of the elderly population (aged 60 years and above) in each province from the 2010 and 2020 national censuses and the 2015 1% National Population Sample Survey were converted into ill-health scores as a measure of self-assessed health, and higher scores represented worse health status perception. Global Moran's I was used to evaluate spatial autocorrelation, range [−1, 1], with a value of 1 as a perfect clustered pattern. Local Moran's I was used to evaluate the tendency of local autocorrelation, and high-high aggregation/low-low aggregation indicated that both target province and its neighboring provinces showed higher/lower ill-health scores. Spatial econometric models were selected by Lagrange multiplier test and Hausman test to explore influencing factors of the self-assessed health of the elderly population. Results In 2010, 2015, and 2020, the national ill-health scores of the elderly population were 1.831, 1.873, and 1.547, respectively, and the corresponding Global Moran's I statistics were 0.347, 0.482, and 0.511, respectively (P<0.01), indicating that the ill-health scores of the elderly population showed a significant spatial positive autocorrelation, and the degree of spatial aggregation was increasing gradually. From 2010 to 2020, the high-high aggregation of ill-health scores among the elderly population was concentrated in the inland northwest, while the low-low aggregation was concentrated in the southeast coast, gradually showing a "southeast-central-northwest" stepped incremental pattern of differentiation. The Lagrange multiplier test and Hausman test suggested that the fixed-effects spatial lagged model was a better choice, and the regression model showed a spatial autocorrelation in the ill-health scores of the elderly population, with an autocorrelation coefficient of 0.3969 (P<0.001); the ill-health scores of the elderly population were negatively correlated with the natural logarithms of gross regional product per capita, and the number of beds in health care facilities per 1000 population, with regression coefficients of −0.8297 and −0.0454 (P<0.05) respectively, and positively correlated with the annual average concentration of PM_2.5, illiteracy rate, and the number of health technicians per 1000 population, with regression coefficients of 0.0033, 0.0297, and 0.0765 (P<0.05), respectively. Conclusion From 2010 to 2020, the overall self-assessed health level of China's elderly population showed an upward trend and a spatial positive autocorrelation, with better self-assessed health in the southeast coast and poorer ratings in the northwestern inland. Additionally, there was a gradual decline in self-assessed health of the elderly population from the southeast to the central regions and further to the northwest in terms of spatial distribution. Economic development level, environmental pollution, health resource allocation, and education level are important factors influencing the self-assessed health of the elderly population.

Rolling circle amplification is a rapid, sensitive and isothermal single-stranded DNA amplification technique that can be used with staining or probes to amplify the detection signal. This technology has been widely used in biological detection and other aspects. The present paper introduces how to design rolling circle amplification, summarize its application in the detection of pathogens, nucleic acid tumor markers, proteins, biological small biomolecules, and viruses in recent years and prospects for future development.
DNA, Single-Stranded ; Nucleic Acid Amplification Techniques

Objective: To explore the synergistic effect of silibinin combined with crizotinib on anaplastic lymphoma kinase positive (ALK+ ) non-small cell lung cancer (NSCLC) cells and its mechanism. Methods: H2228 and H3122 cells were treated with silibinin, crizotinib alone or in combination. Cell proliferation was measured by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and colony formation assay. Migration or invasion ability was tested by wound healing assay or transwell assay, respectively. Expressions of E-Cadherin and vimentin protein were examined by immunofluorescence staining. The protein expressions of ALK, p-ALK, E-Cadherin and Vimentin were detected by western blotting.The anti-cancer effect of silibinin combined with crizotinib in vivo was determined by subcutaneously injecting 2×10⁶ H2228 cells into immunodeficient nude mice. Results: The result of MTT assay showed that the cell viability of H2228 or H3122 treated with 100 μmol/L silibinin was (88.38±4.10)% or (72.27±3.62)%, respectively, marginally decreased compared with that of the control. The 50% inhibitory concentration (IC₅₀) of H2228 cells treated with crizotinib alone or combined with 100 μmol/L silibinin was (917.10±7.75) nmol/L or (238.73±7.67) nmol/L, respectively. The IC₅₀ of H3122 cells treated with crizotinib alone or combined with 100 μmol/L silibinin was (472.50±15.70) nmol/L or (206.10±12.01) nmol/L, respectively. The IC_50s of H2228 and H3122 cells were significantly decreased by combined treatment of crizotinib and silibinin compared to crizotinib treatment alone (P<0.01). When compared with the control group, colony forming ratios of H2228 cells were (83.34±2.72)% in 100 μmol/L silibinin treatment group, (69.42±3.06)% in 400 nmol/L crizotinib treatment group and (27.32±1.42)% in combined treatment group. When compared with the control group, colony forming ratios of H3122 cells were (84.45±5.67)% in 100 μmol/L silibinin treatment group, (45.02±5.83)% in 400 nmol/L crizotinib treatment group and (17.43±3.83)% in combined treatment group. Silibinin combined with crizotinib treatment significantly inhibited the colony formation ability of H2228 and H3122 cells (P<0.01). Migration and invasion results showed that combined treatment of crizotinib and silibinin markedly inhibited the migration and invasion ability of H2228 cells (P<0.01). Western blot results indicated that treated with silibinin alone or in combination of crozitinib for 48 hours, the protein level of E-cadherin in H2228 cells was upregulated, while the expressions of p-ALK and vimentin were downregulated, without obvious alteration of ALK protein expression. In the xenograft model, the mean tumor weight was (9.40±2.58)g in crizotinib treatment group and (4.58±1.07)g in the combined treatment group. The inhibitory effect of tumor growth in vivo of combined treatment was significantly superior to that of crizotinib treatment alone (P<0.05). Conclusion Silibinin enhances the inhibitory effect of crizotinib on ALK positive NSCLC cells, which may be associated with suppression of ALK activity and mesenchymal-epithelial transition.