Objective:To analyze the epidemic trend of influenza-like illness（ILI）cases，etiological detection results，and the evolution of the hemagglutinin（HA）gene of the predominant strains in Hanzhong City，Shaanxi Province during the 2018-2024 influenza seasons.Methods:ILI sentinel surveillance data and network laboratory test results during the 2018-2024 influenza seasons in Hanzhong City，Shaanxi Province were collected for descriptive analysis. The HA gene sequences of 25 predominant strains were obtained through whole-genome deep sequencing method，and then compared with the vaccine strains recommended by the World Health Organization in the same period to analyze the evolution of the virus.Results:A total of 37 770 cases of ILI were reported in Hanzhong City during the 2018-2024 influenza seasons，and the proportion of total ILI cases（ILI%）was 2.87%（37 770/1 316 009）. The epidemic trend of ILI showed an obvious epidemic peak in winter and spring（from December of the current year to March of the following year）. The specimens with the highest positive rate were of type A（H3N2）（39.12%，365/933），and the predominant epidemic strains in each influenza season alternated among A（H1N1）pdm09（in the 2018-2019 and 2022-2023 influenza seasons），A（H3N2）（in the 2019-2020 and 2023-2024 influenza seasons）and B（Victoria）（in the 2021-2022 influenza season）. The phylogenetic relationship gradually became more distant over time across different influenza seasons. Among them，the epidemic strains of A（H1N1）pdm09 belonged to the 6B.1 clade，and the evolution mainly occurred in the Sa and Sb regions of the HA epitope. Meanwhile，the epidemic strains of A（H3N2）belonged to the 3C clade，and the evolution mainly took place in the A，B and C regions of the HA epitope. The strains of the B（Victoria）lineage belonged to the V1a.3a.2 clade，and the evolution mainly occurred in the 120-loop，150-loop，and 190-helix regions of the HA epitope.Conclusions:The influenza epidemic in Hanzhong City has obvious seasonality，and the amino acids of the epidemic strains have shown a certain degree of variation over the years. In future prevention and control work，influenza surveillance should be continuously strengthened，and the change trend of the predominant circulating strains should be closely monitored.

Objective·To observe the impact of hip synovitis on the long-term outcomes of free vascularized fibular grafting(FVFG)for osteonecrosis of femoral head(ONFH).Methods·Between October 2001 and December 2013,370 patients diagnosed with ONFH(556 hips)underwent FVFG.Preoperative synovitis was assessed using magnetic resonance imaging(MRI)and quantified with the Hip Inflammation MRI Scoring System(HIMRISS).Patients were divided into no synovitis group,moderate synovitis group,and severe synovitis group.Harris hip scores and the incidence of total hip arthroplasty were collected with an average follow-up duration of 90.5 months(range:5-215 months).Hip survival failure(defined as a Harris hip score lower than 80 at the final follow-up or the occurrence of total hip arthroplasty)was calculated.Multivariable Cox regression analysis was adopted to compare the influence of different degrees of synovial inflammation on long-term prognosis.Results·The proportion of hip survival failure was 28.0％in patients without synovitis and 28.5％in those with moderate synovitis,whereas it was significantly higher(60.4％)in patients with severe synovitis.The results of multivariable Cox regression analysis showed that severe synovitis was an independent risk factor for poor prognosis(HR 2.06,95％CI 1.21-3.53)after adjusting for age,gender,education level,marital status,ONFH type,affected side of ONFH,smoking history,baseline Harris hip score and other hip MRI-based covariates(collapse,bone marrow edema,and degeneration).Conclusion·Severe synovitis in patients with ONFH significantly increases the failure rate of hip preservation after FVFG,and the severity of synovitis should be considered in surgical decision-making.

Objective:To compare the pregnancy outcomes of surviving fetuses in monochorionic diam-niotic(MCDA)twin pregnancies after selective feticide or spontaneous single intrauterine fetal demise(sIUFD),and to explore the influencing factors of prognosis.Methods:A total of 219 cases of intra-uterine death of one fetus in MCDA twin pregnancies admitted to Peking University Third Hospital from September 2010 to August 2021 were collected.According to the mode of fetal death,they were divided into the spontaneous sIUFD group(120 cases)and the selective feticide group(99 cases).Data on the maternal conditions during pregnancy,the situation of the intrauterine-dead fetus,and pregnancy out-comes were collected for retrospective case-analysis.Results:The live-birth rates of surviving fetuses in the spontaneous sIUFD group and the selective feticide group were 85.0％and 81.8％respectively,and the total perinatal survival rates of surviving fetuses were 73.3％and 81.8％respectively,and there were no statistically significant differences.Compared with the spontaneous sIUFD group,the selective feticide group had a greater gestational week at delivery,and lower rate of preterm birth before 37 weeks,neonatal asphyxia,and early neonatal mortality.Using the gestational week at delivery as the outcome variable,Cox regression analysis showed that the mode of fetal death was not a risk factor affecting the gestational week at delivery of the surviving fetus,while gestational hypertension and the gestational week of fetal death were independent risk factors affecting the gestational week at delivery of the surviving fetus.Using preterm birth before 37 weeks,intrauterine death of the surviving fetus,and abnormal neonatal cranial ultrasound as outcome variables respectively,unconditional logistic regression analysis showed that the mode of fetal death,the gestational week of fetal death,the position of the dead fetus,and fetal complications were independent risk factors affecting the outcomes of the above-mentioned survi-ving fetuses.According to the results of the univariate analysis,the above risk factors were included in the multivariate regression analysis,and the results were the same as those of the univariate analysis.Conclusion:For MCDA twin pregnancy patients with severe twin-related complications,the prognosis of surviving fetuses after selective feticide is better.The proactive intrauterine intervention and treatment are of great significance for improving the prognosis of surviving fetuses.

Objective:To compare the pregnancy outcomes of surviving fetuses in monochorionic diam-niotic(MCDA)twin pregnancies after selective feticide or spontaneous single intrauterine fetal demise(sIUFD),and to explore the influencing factors of prognosis.Methods:A total of 219 cases of intra-uterine death of one fetus in MCDA twin pregnancies admitted to Peking University Third Hospital from September 2010 to August 2021 were collected.According to the mode of fetal death,they were divided into the spontaneous sIUFD group(120 cases)and the selective feticide group(99 cases).Data on the maternal conditions during pregnancy,the situation of the intrauterine-dead fetus,and pregnancy out-comes were collected for retrospective case-analysis.Results:The live-birth rates of surviving fetuses in the spontaneous sIUFD group and the selective feticide group were 85.0％and 81.8％respectively,and the total perinatal survival rates of surviving fetuses were 73.3％and 81.8％respectively,and there were no statistically significant differences.Compared with the spontaneous sIUFD group,the selective feticide group had a greater gestational week at delivery,and lower rate of preterm birth before 37 weeks,neonatal asphyxia,and early neonatal mortality.Using the gestational week at delivery as the outcome variable,Cox regression analysis showed that the mode of fetal death was not a risk factor affecting the gestational week at delivery of the surviving fetus,while gestational hypertension and the gestational week of fetal death were independent risk factors affecting the gestational week at delivery of the surviving fetus.Using preterm birth before 37 weeks,intrauterine death of the surviving fetus,and abnormal neonatal cranial ultrasound as outcome variables respectively,unconditional logistic regression analysis showed that the mode of fetal death,the gestational week of fetal death,the position of the dead fetus,and fetal complications were independent risk factors affecting the outcomes of the above-mentioned survi-ving fetuses.According to the results of the univariate analysis,the above risk factors were included in the multivariate regression analysis,and the results were the same as those of the univariate analysis.Conclusion:For MCDA twin pregnancy patients with severe twin-related complications,the prognosis of surviving fetuses after selective feticide is better.The proactive intrauterine intervention and treatment are of great significance for improving the prognosis of surviving fetuses.

Objective·To observe the impact of hip synovitis on the long-term outcomes of free vascularized fibular grafting(FVFG)for osteonecrosis of femoral head(ONFH).Methods·Between October 2001 and December 2013,370 patients diagnosed with ONFH(556 hips)underwent FVFG.Preoperative synovitis was assessed using magnetic resonance imaging(MRI)and quantified with the Hip Inflammation MRI Scoring System(HIMRISS).Patients were divided into no synovitis group,moderate synovitis group,and severe synovitis group.Harris hip scores and the incidence of total hip arthroplasty were collected with an average follow-up duration of 90.5 months(range:5-215 months).Hip survival failure(defined as a Harris hip score lower than 80 at the final follow-up or the occurrence of total hip arthroplasty)was calculated.Multivariable Cox regression analysis was adopted to compare the influence of different degrees of synovial inflammation on long-term prognosis.Results·The proportion of hip survival failure was 28.0％in patients without synovitis and 28.5％in those with moderate synovitis,whereas it was significantly higher(60.4％)in patients with severe synovitis.The results of multivariable Cox regression analysis showed that severe synovitis was an independent risk factor for poor prognosis(HR 2.06,95％CI 1.21-3.53)after adjusting for age,gender,education level,marital status,ONFH type,affected side of ONFH,smoking history,baseline Harris hip score and other hip MRI-based covariates(collapse,bone marrow edema,and degeneration).Conclusion·Severe synovitis in patients with ONFH significantly increases the failure rate of hip preservation after FVFG,and the severity of synovitis should be considered in surgical decision-making.

Objective:To analyze the epidemic trend of influenza-like illness（ILI）cases，etiological detection results，and the evolution of the hemagglutinin（HA）gene of the predominant strains in Hanzhong City，Shaanxi Province during the 2018-2024 influenza seasons.Methods:ILI sentinel surveillance data and network laboratory test results during the 2018-2024 influenza seasons in Hanzhong City，Shaanxi Province were collected for descriptive analysis. The HA gene sequences of 25 predominant strains were obtained through whole-genome deep sequencing method，and then compared with the vaccine strains recommended by the World Health Organization in the same period to analyze the evolution of the virus.Results:A total of 37 770 cases of ILI were reported in Hanzhong City during the 2018-2024 influenza seasons，and the proportion of total ILI cases（ILI%）was 2.87%（37 770/1 316 009）. The epidemic trend of ILI showed an obvious epidemic peak in winter and spring（from December of the current year to March of the following year）. The specimens with the highest positive rate were of type A（H3N2）（39.12%，365/933），and the predominant epidemic strains in each influenza season alternated among A（H1N1）pdm09（in the 2018-2019 and 2022-2023 influenza seasons），A（H3N2）（in the 2019-2020 and 2023-2024 influenza seasons）and B（Victoria）（in the 2021-2022 influenza season）. The phylogenetic relationship gradually became more distant over time across different influenza seasons. Among them，the epidemic strains of A（H1N1）pdm09 belonged to the 6B.1 clade，and the evolution mainly occurred in the Sa and Sb regions of the HA epitope. Meanwhile，the epidemic strains of A（H3N2）belonged to the 3C clade，and the evolution mainly took place in the A，B and C regions of the HA epitope. The strains of the B（Victoria）lineage belonged to the V1a.3a.2 clade，and the evolution mainly occurred in the 120-loop，150-loop，and 190-helix regions of the HA epitope.Conclusions:The influenza epidemic in Hanzhong City has obvious seasonality，and the amino acids of the epidemic strains have shown a certain degree of variation over the years. In future prevention and control work，influenza surveillance should be continuously strengthened，and the change trend of the predominant circulating strains should be closely monitored.

Objective:To establish an environmental management strategy for the prevention of ventilator-associated pneumonia from the perspective of etiological characteristics and to verify its application effect.Methods:Based on a sampling survey, this study constructed preventive management strategies for ventilator-associated pneumonia by blocking pathogen characteristics from the perspective of both colonization and infection management in patients. From July 2021 to June 2023, a non-synchronous randomized controlled study was conducted, including a control group of 59 cases and an experimental group of 57 cases from ICU of Tianjin Teda Hospital, all of them were mechanically ventilated patients. The effectiveness of the strategy was confirmed.Results:In the control group, there were 35 males and 24 females, with an average age of (46.97 ± 18.84) years. In the experimental group, there were 39 males and 18 females, with an average age of (47.49 ± 13.85) years. During the study period, there were 9 cases of ventilator-associated pneumonia (VAP) in the control group and 2 cases in the experimental group, the difference between the two groups was statistically significant (exact odds ratio=0.031). The duration of mechanical ventilation in the experimental group (122.41 ± 18.36) h, which was shorter than that in the control group (187.62 ± 18.05) h, and the difference was statistically significant ( t=19.28, P<0.05). The length of ICU stay in the experimental group was (8.38 ± 0.79) d, in the control group was (10.99 ± 1.10) d, the difference between them was statistically significant ( t=14.66, P<0.05). On the 7th day, there were 7 cases of positive pathogenic bacteria in sputum culture in the experimental group, which was significantly different from the 29 cases in the control group ( χ2=16.73, P<0.05). Conclusions:The vector management strategy for preventing ventilator-associated pneumonia by blocking etiological characteristics can reduce the incidence of VAP, shorten the duration of mechanical ventilation and ICU stay, and reduce the pathogen load in the sputum of mechanically ventilated patients on the 7th day.

Objective: To monitor the prevelance of Neisseria meningitidis among healthy children and adolescents aged 3-18 in Anhui Province, so as to provide support for epidemic cerebrospinal meningitis prevention and control. Methods: From September to October in 2021 and 2022, 4 033 healthy children and adolescents aged 3-18 were selected by stratified random sampling from Anhui Province, including areas north of the Yangtze River (Bozhou, Fuyang, Bengbu, Huainan, Chuzhou, Hefei) and areas south of the Yangtze River (Wuhu, Maanshan, Tongling, Anqing, Chizhou, Xuancheng) and the secretions of children and adolescents were collected from the posterior pharyngeal wall above the uvula, and the strains were identified by bacterial culture and nucleic acid detection. McNemar test and Kappa consistency test were used for statistical analysis. Chisquare test and Chisquare trend test were used to compare the rates. Results: The carrier rates of Neisseria meningitidis were 0.47% and 1.07%, respectively. The sensitivity of nucleic acid detection was higher. Among the detected bacteria, group B accounted for the largest proportion of 76.74%. It was followed by group C (4.65%), group Y (4.65%), group W 135 (2.33%) and group X (2.33%). The bacteria bearing rate of male students was higher than that of female students (χ2=11.44); with the increase of age, the bacteria bearing rate of children and adolescents showed an increasing trend (χ2trend=42.69); the bacterial bearing rate of children and adolescents in the north of the Yangtze River was higher than that in the south of the Yangtze River (χ2=23.19); the bacteria bearing rate of children and adolescents without immune history was higher than that with immune history (χ2=11.02)(P<0.01). Conclusions Neisseria meningitidis group B has become an epidemic strain in Anhui Province, and senior children and adolescents have become the key population of epidemic prevention and control. It is necessary to continue to do a good job in the surveillance of epidemic cerebrospinal meningitis disease and focuse on group B disease cases, so as to prevent the occurrence of cluster outbreaks in schools.

OBJECTIVE To study the protective effect and possible mechanism of soybean isoflavones against threatened miscarriage rats. METHODS Female mice were selected to promote estrus and mate with male mice. After pregnancy， they were randomly divided into normal group （purified water， i.g.， n＝10）， model group （purified water， i.g.， n＝9）， positive control drug group （progesterone 4 mg/kg， i.m.， n＝9）， low-， medium- and high-dose soybean isoflavone groups （25， 50 and 100 mg/kg， i.g.， n＝10）. Except for the normal group， the rest were given mifepristone+misoprostol on the 8th day of pregnancy to establish threatened miscarriage model， and then given purified water or drugs， once a day， on days 1-7 and 9-12 of pregnancy， respectively. At 14 days of pregnancy， the rates of fetal protection were counted. Serum levels of β-human chorionic gonadotrophin （β-HCG） and progesterone （P） in rats were detected. Pathological and morphological changes in rat placenta and decidua tissues were observed， and the apoptosis indexes of cells were detected； mRNA and protein expressions of factor of apoptosis related （Fas）， factor of apoptosis related ligand （FasL）， proliferating cell nuclear antigen （PCNA） and heparin binding epidermal growth factor （HB-EGF） were determined in placenta tissues， and mRNA and protein expressions of Fas， PCNA and HB-EGF in decidua tissues were detected. RESULTS In the model group， the placental tissues of rats were hyperemia and dilatation， with fewer and irregular blood vessels； severe stromal edema，inflammatory cell infiltration and iron-choledrin depositionwere observed. Compared with model group， the fetal survival rates， serum levels of β-HCG and P， the expressions of PCNA and HB-EGF mRNA and proteins in the placenta and decidua tissue of soybean isoflavone groups increased significantly （P＜ 0.05）， while pathological changes were improved significantly； cell apoptosis index in the placenta and decidua tissue， the expressions of Fas， FasL mRNA and proteins in the placenta and Fas mRNA and protein in the decidua tissue decreased significantly （P＜0.05）. The effect of soybean isoflavones was dose-dependent （P＜0.05）. CONCLUSIONS Soybean isoflavone has protective effect on threatened miscarriage， the mechanism of which is related to down-regulating the expressions of Fas and FasL mRNA and protein at the maternal-fetal interface， and up-regulating the expressions of mRNA and protein of PCNA and HB- EGF.

Objective:To analyze the epidemiological characteristics and pathogen spectrum of influenza outbreaks in Shaanxi Province from 2014 to 2023 and provide basis reference for strengthening regional influenza prevention and control.Methods:The data were collected from the Public Health Emergency Management Information System of the China Disease Prevention and Control Information System and the China Influenza Surveillance Information System. On-site epidemiological investigation information and etiological test results of influenza network laboratories reported in Shaanxi Province during 2014-2023 were collected, and descriptive analysis was conducted on the time, region, and location distribution of influenza outbreaks. SPSS 25.0 software was used for statistical analysis.Results:A total of 386 influenza outbreaks were reported in Shaanxi from 2014 to 2023, with a total attack rate of 1.81% (14 880/821 001). The epidemic peaks mainly occurred in winter and spring (November to March of the following year), and there was an alternating pattern of epidemic peaks in different years (the early peak was in December, and the late peak was in March of the following year). The epidemic areas were mainly concentrated in the Qinba Mountains of southern Shaanxi (209, 54.15%) and Guanzhong Plain (173, 44.82%). The epidemic places were mainly distributed in primary schools (239, 61.92%), and the differences of epidemic areas and places were statistically significant (all P<0.001). Influenza A(H3N2) viruses were the predominant pathogen in the outbreak (849, 57.76%), and influenza A(H3N2), B (Victoria) lineage and A(H1N1)pdm09 virus alternately dominated the epidemic peak in different years. Conclusions:The peak of influenza outbreaks in Shaanxi Province was winter and spring during 2014-2023. Primary schools in the Qinba Mountains of southern Shaanxi and Guanzhong Plain should be targeted for prevention and control. In the prevention and control programs, close attention should be paid to the changing trend of dominant strains. Effective intervention measures should be targeted to the high-incidence areas and seasons.