ObjectiveTo optimize the technical parameters of mouse embryo transfer (including oviduct opening method, pseudopregnant recipient body weight, number of embryos transferred per recipient, and unilateral vs. bilateral oviduct transfer), improve the efficiency of embryo transfer (the pregnancy rate of recipient female mice after embryo transfer is used as the evaluation index), and improve the utilization rate of high-quality embryo germplasm resources (the birth rate of mice after embryo transfer is used as the evaluation index). Methods560 SPF-grade ICR mice and 440 C57BL/6J mice were used as experimental animals. 2-cell embryos were obtained through in vitro fertilization. A single-factor controlled variable method was used to systematically investigate the effects of four factors, including oviduct opening method, pseudopregnant recipient body weight, number of embryos transferred per recipient, and unilateral vs. bilateral oviduct transfer, on the pregnancy rate and birth rate of mouse embryo transfer. ResultsThe pregnancy rate of recipients with an opening made in the oviduct using a 26G syringe needle reached 90%, which was significantly higher than the 43% in the group with oviduct openings cut by Vannas scissors (P<0.05). Pseudopregnant recipients weighing 29-35 g exhibited optimal embryo transfer outcomes, with a pregnancy rate of 90% and a birth rate of 44%, and no pups were crushed by the recipient mothers. The highest birth rate of 42% was observed in the group receiving 16-25 embryos per recipient. Transferring 26-35 embryos per recipient achieved a 90% pregnancy rate and maximized embryo utilization efficiency. However, transfer efficiency decreased significantly when more than 35 embryos were transferred. Transfer of 24-26 embryos per recipient balanced relatively high pregnancy and birth rates. Bilateral oviduct transfer of mouse embryos yielded slightly higher pregnancy and birth rates than unilateral transfer, but the difference was not statistically significant (P>0.05). ConclusionSelecting pseudopregnant recipient female mice weighing 29-35 g, using a 26G syringe needle to make an opening in the oviduct, and controlling the number of transferred embryos at 24-26 per recipient can effectively improve the success rate of embryo transfer and achieve efficient utilization of high-quality embryo germplasm resources.

The aim of this study is to investigate the immune effect of H9 subtype avian influenza virus(AIV)NP protein on mice and lay the foundation for the development of avian influenza vi-rus(AIV)vaccine.The H9N2 virus NP gene amplification product was cloned into the pET-32a expression vector,and the protein expression was verified by SDS-PAGE and Western blot,and the immune effect was evaluated by measuring the secretion of supernatant multicytokines in mouse splenocytes culture.The results showed that the total length of the coding region sequence of NP gene was 1 497 bp,NP recombinant proteins exist in both soluble and insoluble protein forms,and the specific bands were visible in Western blot.After immunizing mice,serum produces IgG-bind-ing antibodies with antibody titers of 1∶40 000.Compared with the control group,IL-2,IL-5 and IL-13 were significantly increased(P＜0.001),and the secretion of IL-6 was significantly increased compared with the control group.IL-4 and IL-12 p70 secretions were elevated compared with con-trols,but there was no significant difference.Compared with the control group,the secretions of IL-1β,IL-18,GM-CMF,TNF-α and IFN-γ were inhibited,but the difference was not significant(P＞0.05).The results showed that NP recombinant protein is a good immunogen,laying a foundation for in-depth research on influenza vaccine.

Background: Chicken anemia virus (CAV) causes chicken infectious anemia, which results in immunosuppression; the virus has spread widely in chicken flocks in China. Objectives: The aim of this study was to understand recent CAV genetic evolution in chicken flocks in Guangxi Province, southern China. Methods: In total, 350 liver samples were collected from eight commercial broiler chicken farms in Guangxi Province in southern China from 2018 to 2020. CAV was detected by conventional PCR, and twenty CAV complete genomes were amplified and used for the phylogenetic analysis and recombination analysis. Results: The overall CAV-positive rate was 17.1%. The genetic analysis revealed that 84 CAVs were distributed in groups A, B, C (subgroups C1-C3) and D. In total, 30 of 47 Chinese CAV sequences from 2005-2020 belong to subgroup C3, including 15 CAVs from this study. There were some specific mutation sites among the intergenotypes in the VP1 protein. The amino acids at position 394Q in the VP1 protein of 20 CAV strains were consistent with the characteristics of a highly pathogenic strain. GX1904B was a putative recombinant. Conclusions Subgroup C3 was the dominant genotype in Guangxi Province from 2018–2020.The 20 CAV strains in this study might be virulent according to the amino acid residue analysis. These data help improve our understanding of the epidemiological trends of CAV in southern China.

Objective:To investigate the awareness rate of " 1+ 1+ 1" contracted residents in the outer suburbs of Shanghai on the extended prescription policy of the family doctor contract service, and to analyze the influencing factors.Methods:From March to May, 2021, the cluster random sampling method was used to select one community health service center in Fengxian district, Shanghai, and a smart voice telephone assistant survey was conducted among the contracted residents aged 18 and above in the area, to understand their awareness of the extended prescription policy. χ2 Test was used for single factor analysis on the influence of different factors on the policy awareness of the contracted residents, while a multivariate analysis was performed by binary logistic regression, presenting P<0.05 as statistically significant. Results:A total of 13 495 " 1+ 1+ 1" contracted residents were surveyed via phone calls. Their awareness rate of extended prescription policy was 67.5% (9 115/13 495), while those with higher awareness rates were patients with ≥2 chronic diseases (92.3%), patients with 1 chronic disease (88.5%) and those aged 81 and above (88.4%). Logistic regression analysis showed that age, marital status, the number of chronic diseases and signing duration were all independent factors influencing the awareness of extended prescription policy (all P<0.05), while whether the residents were key population groups presented no significant influence on the awareness of extended prescription policy ( P=0.431). Conclusions:The awareness rate of " 1+ 1+ 1" contracted residents in the outer suburbs of Shanghai to the extended prescription policy needs to be further improved and publicity should also be strengthened to extend the policy benefit coverage.

Objective:To explore the clinical characteristics of patients infected with 2019 novel coronavirus (2019-nCoV) Omicron variant in Zhuhai City.Methods:A retrospective study was conducted to compare the clinical characteristics of patients infected with 2019-nCoV Omicron variant (Omicron variant group, 39 cases) from January 13 to January 25, 2022, and those infected with 2019-nCoV non-Omicron variant (non-Omicron variant group, 98 cases) from January 17 to February 17, 2020, in the Fifth Affiliated Hospital of Sun Yat-sen University. Statistic methods were used by Mann-Whitney U test, chi-square test and Fisher exact probability test. Results:Among adults, the age of 21 patients in Omicron variant group was younger than that of 93 patients in non-Omicron variant group (34.0(26.0, 40.5) years vs 50.0(36.0, 62.0) years, Z=-3.81, P<0.001). Patients with underlying diseases in Omicron variant group were fewer than those in non-Omicron variant group (4.8%(1/21) vs 31.2%(29/93), χ2=6.17, P=0.013). The clinical classification of the Omicron variant group was mainly mild (71.4%(15/21)) or common type (28.6%(6/21)), while the non-Omicron variant group was dominated with common type (57.0%(53/93)) and severe type (23.7%(22/93)), and the clinical classification of the two groups had statistically difference ( χ2=31.79, P<0.001). The time of positive nucleic acid in Omicron variant group was longer than that in non-Omicron variant group (14.0(10.5, 16.5) d vs 8.5(4.0, 12.0) d, Z=-3.56, P<0.001). The proportion of pneumonia in Omicron variant group was less than that in non-Omicron variant group (28.6%(6/21) vs 86.0%(80/93), χ2=30.52, P<0.001). Differences were all statistically significant. There was no significant difference of the clinical characteristics in pediatric patients, but the proportion of children infected with 2019-nCoV Omicron variant was significantly higher than that infected with 2019-nCoV non-Omicron variant (46.2%(18/39) vs 5.1%(5/98), χ2=33.65, P<0.001). Conclusions:Adults infected with 2019-nCoV Omicron variant in Zhuhai City present with milder clinical symptoms, less proportion of pneumonia, but the time of positive nucleic acid is longer. The clinical characteristics of children infected with 2019-nCoV Omicron variant are not specific, while the proportion of children infected with 2019-nCoV Omicron variant is significantly higher.

Objective:To analyze the clinical characteristics of patients infected with 2019-nCoV Omicron variants BA.1 and BA.2 in Zhuhai city.Methods:A retrospective study was conducted to compare clinical characteristics of patients infected with 2019-nCoV Omicron variants BA.1 and BA.2, who were admitted in the Fifth Affiliated Hospital of Sun Yat-sen University during January 13 to March 8 2022. The Mann-Whitney U-test or Kruskal-Wallis H test was used for quantitative data, and the χ2 test or Fisher’s exact test was used for qualitative data. Results:Among 122 patients infected with the Omicron variant, there was 79 adults (BA.1 23 cases, BA.2 56 cases) and 43 children (BA.1 19 cases, BA.2 24 cases). In adults, patients infected with BA.2 sub-variant had a higher baseline viral loads at admission than BA.1 infected patients [7.64(6.92, 8.55) lg copies/mL vs. 6.64(6.04, 7.34) lg copies/mL; Z=-3.022, P=0.003]; compared to BA.1 patients, BA.2 patients had a higher proportion of mild and asymptomatic cases and a lower proportion of common infection cases ( χ2=8.052, P=0.012); the proportion of patients with pneumonia imaging changes in BA.1 patients was higher than that in BA.2 infected patients [(6/23, 26.1%) vs. (2/56, 3.6%); χ2=6.776, P=0.009). In children, the rate of fever in BA.2 group was higher than that in BA.1 group [(16/24, 66.7%) vs. ( 5/19, 26.3%); χ2=6.910, P=0.009); the proportion of patients with reduced lymphocyte counts in BA.2 group was higher than that in BA.1 group [(17/24, 70.8%) vs.(1/19, 5.3%); χ2=18.734, P<0.001). Compared with adult cases, children with BA.2 sub-variant infection had higher fever rate [(16/24, 66.7%) vs. (19/56, 33.9%); χ2=7.317, P=0.007). The viral loads of daily nasal swabs in BA.2 infected patients increased first and then decreased in both adults and children, with a greater decrease than BA.1 during the first two weeks. Conclusions:Compare with 2019-nCoV Omicron variant BA.1, BA.2 has a higher baseline viral loads in adults, which means much more contagious in the early stages. But the viral load drops faster in BA.2 infected patients. In children, BA.2 patients are more likely to have fever and reduced lymphocyte counts, which indicates that the prevention and control of 2019-nCoV Omicron sub-variant BA.2 is more difficult.

Objective:To investigate the intention of medical students to be vaccinated against COVID-19 and to analyze the influencing factors.Methods:A self-filled electronic questionnaire survey was conducted among medical students from a medical school in Shanghai randomly selected from June 21 to 29, 2021. The questionnaire contained items of basic information, intention for COVID-19 vaccination, awareness of COVID-19 prevention measures and awareness of COVID-19 vaccine. Logistic regression was used to analyze the influencing factors.Results:The average age of the 966 respondents was (20.4±2.9) years, and 63.6% (614/966) of them were female;23.7% (229/966) of them had family members or relatives who had participated in anti-pandemic work or volunteer service;90.6% (875/966) of the respondents expressed they were very willing or willing to be vaccinated against COVID-19. The majority of the respondents thought that “COVID-19 infection is very serious” (94.3%, 911/966), “good protection can effectively prevent COVID-19 infection” (92.4%, 893/966), and “they can fully implement all kinds of protection measures” (73.5%, 710/966). About half of the respondents (51.8%, 501/966) knew about the adverse reactions and contraindications of COVID-19 vaccine. The low protected capability (47.4%, 458/966), short duration of protection (50.6%, 489/966), and many side effects (48.7%, 470/966) were the major concerns about COVID-19 vaccine. Logistic regression analysis showed that people thought that “COVID-19 infection is very serious” ( OR=5.30, 95 %CI:2.60-10.81, P<0.001), thought that “good protection can effectively prevent COVID-19 infection” ( OR=2.46, 95 %CI:1.26-4.81, P=0.009), thought that “they can fully implement all kinds of protection measures” ( OR=2.55, 95 %CI:1.53-4.25, P<0.001) were more willing to receive COVID-19 vaccination. While those concerned about vaccine quality did the opposite ( OR=0.29, 95 %CI:0.13-0.65, P=0.003). Conclusions:Medical students have a high intention of vaccination against COVID-19. The vaccine-related knowledge quality should be emphasized in future publicity to further enhance the intention of COVID-19 vaccination.

Objective: To understand the status quo and differences of the rights and interests of primary medical staff in a community, and to provide targeted suggestions for improving the rights of such staff. Methods: From October to November 2018, a questionnaire survey was conducted on all the medical staff of 8 community health service centers in a district of Shanghai, and 562 valid samples were obtained. Results: The primary medical staff had the highest demands for " pay rise" (4.783±0.598), " paid vacation" (4.569±0.873)and " additional reserve fund" (4.553±0.963); the lowest demands were placed on " education-based promotion" (3.797±1.382), " refresher training" (3.801±1.314), and " opinion feedback mechanism" (4.018±1.223). At the same time, the rights and interests of these staff in different occupational categories were significantly different(P<0.05)in " daily reimbursement" , " housing subsidy" , " refresher training" and " opinion feedback mechanism" . Conclusions The salary demands of the primary medical staff are the most obvious, and there are differences in the demands of medical staff in different occupational categories. It is suggested to establish a more reasonable salary system and pay attention to the differentiated appeals of different medical personnel.

Objective Under the linkage reform of family doctor service and medical insurance payment ,to study the family doctors′ career cognitive and expectations in order to improve the endogenous power of the family doctor system development ,and push forward the reform with sustainable effects .Methods All the family doctors in Changning were surveyed. There were 154 family doctors surveyed in the first phase of 2013 ,and 143 in the second phase of 2016 .The data were subject to descriptive statistics .Results About 80％ of the family doctors had a clear understanding of the family doctor system in 2016 ,with the proportion of family doctors clearly understanding their duties risen from 55.26％ (84/152)in 2013 to 61.27％ (87/142)in 2016 .Self-assessment of their work value and professional reputation were more positive significantly .70％ of them believed their social status as above average. The proportion of family doctors who were very confident/confident" in the development of community health services and family doctor system increased from 31.72％ (46/145) to 47.20％ (59/125)and from 31.72％ (46/145)to 52.42％ (65/124)respectively .Conclusions The occupational cognition and career expectations of family doctors in Changning district have been significantly improved ,which can guide their behavior towards reform objectives and propel the family doctor system progress smoothly .

Objective To evaluate the motivation effect of family doctors′ contracting service and health insurance compensation mechanism from the perspective of income change and income satisfaction of family doctors .Methods The situation about salary compensation plan reform and the change of income level and structure were learnt from interviews on the management personnel and questionnaire surveys of family doctors in 2013 and 2016 .The data were subject to descriptive statistics .Results The proportion of family doctors earning between 8000 and 10000 yuan in 2016 rose to 67.16％ (90/134 ) from 18.18％ (26/143 ) in 2013.11.72％ (15/128 ) of family doctors′contracting service fee amounted to over 50％ of their income. The number of family doctors who were dissatisfied with their income has fallen by 28.52％ .There were still 51.90％ (68/131)of the family doctors who were not satisfied with their income and 24.64％ (34/138)of them held the incentives of performance appraisal as a failure .Conclusions The income of family doctors has been greatly increased in the last three years.Contracting service fee plays a key role in motivating these doctors , but three risks also need to be prevented in the process of further reform .