In order to investigate the role of sRNA OxyS in the pathogenicity of Salmonella typhi-murium infection,the OxyS gene deletion strain ATCC25241 △OxyS and the back-complemented strain ATCC25241 △OxyS/OxyS of Salmonella typhimurium ATCC25241 were constructed by using λRed homologous recombination technique.We investigated the effect of OxyS deletion on the biological characteristics and pathogenicity of Salmonella typhimurium ATCC25241.The re-sults showed that the deletion of OxyS did not affect the growth rate,the ability of biofilm forma-tion,and the ability of adhesion,invasion and intracellular survival of Salmonella typhimurium,but significantly reduced the motility of Salmonella typhimurium as well as its ability to survive in alkaline and oxidative environments.The results of mouse infection test showed that OxyS dele-tion caused a significant decrease in the virulence of Salmonella typhimurium in mice,and toxicity is reduced obviously.The qPCR results also showed that OxyS deletion could lead to changes in the transcript levels of a number of virulence-related genes of Salmonella typhimurium such as pipB,orf245,csgA,invH,tatA,sipA,sipB,and so on.The above results indicate that OxyS gene affects the biological characteristics and pathogenicity of Salmonella typhimurium and is an important virulence regulator of Salmonella typhimurium.

In order to establish a serological method for the detection of bovine respiratory syncytial virus,the prokaryotic expression of four proteins of BRSV,G,F,P,and M was carried out,and the most suitable coating antigen was screened to establish an indirect ELISA detection method.The results showed that the four recombinant proteins of BRSV,rG,rF,rP and rM were successfully expressed.The results of checkerboard screening showed that the P/N value of rG protein was the largest,which was determined to be the best coating antigen established by indirect ELISA meth-od.The optimal reaction conditions for indirect ELISA were as follows:the mass concentration of rG protein coating was 1 mg/L,37℃ for 2 h;3％BSA 37℃ block for 1 h;Serum was diluted 1∶50 and incubated at 37℃ for 1h;Secondary antibody 1∶5 000 dilution,37℃ for 30min;The color development conditions of the substrate were 37℃ for 15 min;Thirty negative sera were selected,and the cut-off value was determined to be 0.63 by the established indirect ELISA method.The re-sults of the specificity test showed that the indirect ELISA method established in this test only recognized BRSV-positive serum,and did not react with IBRV,BCoV,and BPIV3-positive serum.The results of repeatability test showed that the method had good repeatability,and the coefficient of variation within and between batches was less than 10％.The results of the sensitivity test showed that the BRSV-positive serum was still positive when diluted to 1∶8 192.The indirect ELISA method established in this experiment was used to detect 100 clinical serum samples at the same time,and the total coincidence rate of the two reached 90.48％,the positive coincidence rate was 93.42％,and the negative coincidence rate was 82.75％.The indirect ELISA established in this test can be used for the detection of bovine respiratory syncytial virus in clinical practice.

Background and purpose:Internal mammary sentinel lymph node biopsy(IMSLNB)is a minimally invasive diagnostic technique for regional lymph nodes in breast cancer,which can provide accurate lymph staging and guide adjuvant treatment decision,but its clinical application has been controversial.The purpose of this study was to investigate the prognosis of IMSLNB in early breast cancer.Methods:In this study,a retrospective cohort of 7 949 patients with breast cancer from January 1,2016 to December 31,2021 was analyzed.After applying propensity score matching,the patients were divided into IMSLNB group and no-IMSLNB group,and the regional recurrence-free survival(RRFS),local recurrence-free survival(LRFS),distant metastasis-free survival(DMFS),disease-free survival(DFS)and overall survival(OS)of the two groups were compared.This study was approved by the Clinical Research Ethics Committee of the Affiliated Tumor Hospital of Shandong First Medical University(approval number:SDTHEC20130324).Results:A total of 990 patients were included in the final analysis(330 in the IMSLNB group and 660 in the no-IMSLNB group).IMSLN metastasis was found in 54 patients in the IMSLNB group,including 47 patients with axillary lymph node(ALN)metastasis and 7 patients with IMSLN metastasis only.The IMSLN transfer rate was 16.4%.The median follow-up of 41 months showed that the IMSLNB group demonstrated better 3-year DFS[98.4%vs 94.2%,hazard ratio(HR)=0.509;95%CI:0.312-0.828,P=0.007]and 5-year DFS(92.5%vs 87.3%,HR=0.214,95%CI:0.206-0.222,P=0.011)compared with no-IMSLNB group.However,no significant differences were observed in 3-year OS(99.1%vs 99.4%,HR=0.618,95%CI:0.231-1.655,P=0.338)or 5-year OS(98.5%vs 99.1%,HR=0.52,95%CI:0.51-0.53,P=0.392)between the two groups.The 3-year RRFS in the IMSLNB group was better compared with the no-IMSLNB group(99.09%vs 97.73%,HR=0.066;95%CI:0.061-0.071,P=0.048),while no significant differences were observed in 3-year LRFS(99.70%vs 98.19%,HR=0.209;95%CI:0.201-0.217,P=0.130)or DMFS(95.76%vs 96.06%,HR=0.865,95%CI:0.858-0.872,P=0.820)between the two groups.The exploratory subgroup analysis of DFS revealed that patients in the following subgroups could significantly benefit from IM-SLNB(P＜0.05):diagnosis age(≤50 years),premenopausal status,BMI(≤24),lymphovascular invasion(LVI,present),tumor location(lateral),molecular subtype[hormone receptor positive(HR+)/human epidermal growth factor receptor 2 negative(HER2-)],histological type(invasive ductal carcinoma),and axillary lymph node status(positive).Conclusion:IMSLNB can provide more accurate regional lymph node staging for early breast cancer,help optimize adjuvant radiotherapy strategies,and improve patients'DFS and RRFS.It can be promoted as a minimally invasive staging technique for regional lymph nodes.

Objective To evaluate the efficacy of arthroscopic double row suture technique combined with knotless suture bridge technique in repairing medium and large rotator cuff tears.Methods 92 medium and large rotator cuff tears patients from January 2018 to October 2022 were randomly divided into two groups with 46 cases in each group.The observation group was administrated with arthroscopic double row suture combined with knotless suture bridge technique,while the control group was treated with arthroscopic single row suture combined with knotless suture bridge technique.The two groups were compared before and 3,6,and 12 months after surgery in terms of intermediate,medial and lateral T2 values of supraspinatus tendons,shoulder joint range of motion,and the scores on related scales[Constant-Murley scale,University of California,Los Angeles(UCLA)shoulder joint grading system,visual analogue scale(VAS)score],as well as the acromion-humeral head distance(A-H distance).And the joint stiffness and rotator cuff tears were collected from the two groups within 12 months after the operation.Results At 3,6 and 12 months after surgery,the intermediate,medial and lateral T2 values of supraspinatus tendons in both groups were gradually decreased,and were significantly lower than those before surgery,the differences were statistically significant(P<0.05),and the intermediate,medial and lateral T2 values of supraspinatus tendons at each time point in the observation group were significantly lower than those in the control group,the differences were statistically significant(P<0.05);At 3,6,and 12 months after surgery,the anterior flexion range of motion,lateral rotation range of motion,and A-H head distance of both groups were seeing a gradual increase,and the values were significantly higher than those before the treatment,the differences were statistically significant(P<0.05).The anterior flexion range of motion,lateral rotation range of motion and A-H head distance at each time point in the observation group were significantly greater than those in the control group,the differences were statistically significant(P<0.05);At 3,6,and 12 months after surgery,the Constant-Murley and UCLA scales of both groups were seeing a gradual increase,and the values were significantly higher than those before the treatment,the differences were statistically significant(P<0.05),and The Constant-Murley and UCLA scales of the observation group at each time point were significantly higher than those of the control group,the differences were statistically significant(P<0.05);At 3,6,and 12 months after surgery,the VAS score in both groups was lower than that before operation,the difference was statistically significant(P<0.05),the VAS score of the observation group at 3 months after surgery was significantly lower than that of the control group,the difference was statistically significant(P<0.05);12 months after surgery,the incidence of joint stiffness and rotator cuff retear in observation group were 2.17%and 0.00%,significantly lower than those in control group(17.39%and 13.04%),the differences were statistically significant(P<0.05).Conclusion The application of arthroscopic double row suture combined with knotless suture bridge technique can effectively promote postoperative rotator cuff tissue healing,improve the range of motion,function of the shoulder joint and A-H head distance,relieve shoulder pain and greatly reduce the occurrence of postoperative rotator cuff tear and joint stiffness compared with arthroscopic single row suture combined with knotless suture bridge technique.It is worthy clinical application.

Objective To evaluate the efficacy of arthroscopic double row suture technique combined with knotless suture bridge technique in repairing medium and large rotator cuff tears.Methods 92 medium and large rotator cuff tears patients from January 2018 to October 2022 were randomly divided into two groups with 46 cases in each group.The observation group was administrated with arthroscopic double row suture combined with knotless suture bridge technique,while the control group was treated with arthroscopic single row suture combined with knotless suture bridge technique.The two groups were compared before and 3,6,and 12 months after surgery in terms of intermediate,medial and lateral T2 values of supraspinatus tendons,shoulder joint range of motion,and the scores on related scales[Constant-Murley scale,University of California,Los Angeles(UCLA)shoulder joint grading system,visual analogue scale(VAS)score],as well as the acromion-humeral head distance(A-H distance).And the joint stiffness and rotator cuff tears were collected from the two groups within 12 months after the operation.Results At 3,6 and 12 months after surgery,the intermediate,medial and lateral T2 values of supraspinatus tendons in both groups were gradually decreased,and were significantly lower than those before surgery,the differences were statistically significant(P<0.05),and the intermediate,medial and lateral T2 values of supraspinatus tendons at each time point in the observation group were significantly lower than those in the control group,the differences were statistically significant(P<0.05);At 3,6,and 12 months after surgery,the anterior flexion range of motion,lateral rotation range of motion,and A-H head distance of both groups were seeing a gradual increase,and the values were significantly higher than those before the treatment,the differences were statistically significant(P<0.05).The anterior flexion range of motion,lateral rotation range of motion and A-H head distance at each time point in the observation group were significantly greater than those in the control group,the differences were statistically significant(P<0.05);At 3,6,and 12 months after surgery,the Constant-Murley and UCLA scales of both groups were seeing a gradual increase,and the values were significantly higher than those before the treatment,the differences were statistically significant(P<0.05),and The Constant-Murley and UCLA scales of the observation group at each time point were significantly higher than those of the control group,the differences were statistically significant(P<0.05);At 3,6,and 12 months after surgery,the VAS score in both groups was lower than that before operation,the difference was statistically significant(P<0.05),the VAS score of the observation group at 3 months after surgery was significantly lower than that of the control group,the difference was statistically significant(P<0.05);12 months after surgery,the incidence of joint stiffness and rotator cuff retear in observation group were 2.17%and 0.00%,significantly lower than those in control group(17.39%and 13.04%),the differences were statistically significant(P<0.05).Conclusion The application of arthroscopic double row suture combined with knotless suture bridge technique can effectively promote postoperative rotator cuff tissue healing,improve the range of motion,function of the shoulder joint and A-H head distance,relieve shoulder pain and greatly reduce the occurrence of postoperative rotator cuff tear and joint stiffness compared with arthroscopic single row suture combined with knotless suture bridge technique.It is worthy clinical application.

Background and purpose:Internal mammary sentinel lymph node biopsy(IMSLNB)is a minimally invasive diagnostic technique for regional lymph nodes in breast cancer,which can provide accurate lymph staging and guide adjuvant treatment decision,but its clinical application has been controversial.The purpose of this study was to investigate the prognosis of IMSLNB in early breast cancer.Methods:In this study,a retrospective cohort of 7 949 patients with breast cancer from January 1,2016 to December 31,2021 was analyzed.After applying propensity score matching,the patients were divided into IMSLNB group and no-IMSLNB group,and the regional recurrence-free survival(RRFS),local recurrence-free survival(LRFS),distant metastasis-free survival(DMFS),disease-free survival(DFS)and overall survival(OS)of the two groups were compared.This study was approved by the Clinical Research Ethics Committee of the Affiliated Tumor Hospital of Shandong First Medical University(approval number:SDTHEC20130324).Results:A total of 990 patients were included in the final analysis(330 in the IMSLNB group and 660 in the no-IMSLNB group).IMSLN metastasis was found in 54 patients in the IMSLNB group,including 47 patients with axillary lymph node(ALN)metastasis and 7 patients with IMSLN metastasis only.The IMSLN transfer rate was 16.4%.The median follow-up of 41 months showed that the IMSLNB group demonstrated better 3-year DFS[98.4%vs 94.2%,hazard ratio(HR)=0.509;95%CI:0.312-0.828,P=0.007]and 5-year DFS(92.5%vs 87.3%,HR=0.214,95%CI:0.206-0.222,P=0.011)compared with no-IMSLNB group.However,no significant differences were observed in 3-year OS(99.1%vs 99.4%,HR=0.618,95%CI:0.231-1.655,P=0.338)or 5-year OS(98.5%vs 99.1%,HR=0.52,95%CI:0.51-0.53,P=0.392)between the two groups.The 3-year RRFS in the IMSLNB group was better compared with the no-IMSLNB group(99.09%vs 97.73%,HR=0.066;95%CI:0.061-0.071,P=0.048),while no significant differences were observed in 3-year LRFS(99.70%vs 98.19%,HR=0.209;95%CI:0.201-0.217,P=0.130)or DMFS(95.76%vs 96.06%,HR=0.865,95%CI:0.858-0.872,P=0.820)between the two groups.The exploratory subgroup analysis of DFS revealed that patients in the following subgroups could significantly benefit from IM-SLNB(P＜0.05):diagnosis age(≤50 years),premenopausal status,BMI(≤24),lymphovascular invasion(LVI,present),tumor location(lateral),molecular subtype[hormone receptor positive(HR+)/human epidermal growth factor receptor 2 negative(HER2-)],histological type(invasive ductal carcinoma),and axillary lymph node status(positive).Conclusion:IMSLNB can provide more accurate regional lymph node staging for early breast cancer,help optimize adjuvant radiotherapy strategies,and improve patients'DFS and RRFS.It can be promoted as a minimally invasive staging technique for regional lymph nodes.

Objective:To investigate the current situation and correlation between mental health and stressors of new professional master's degree graduates in clinical medicine, and to provide empirical support for improving student mental health.Methods:An online questionnaire survey was conducted among 3 587 fresh graduate students with master's degree in clinical medicine from 65 training institutions in China. SPSS 26.0 was used to compare and analyze the measurement data. Descriptive statistics were used to analyze the mental health using Symptom Checklist-90 (SCL-90) and the current status of stressors. The influence factors and correlation between mental health and stressors were analyzed by means of differentiation analysis and correlation analysis.Results:The SCL-90 overall mean score as well as the scores of obsessive-compulsive symptoms, interpersonal sensitivity, depression, terror, anxious, psychoticism, and hostility of new professional master's degree graduates in clinical medicine were all higher than the national norm ( P<0.05). Among the participants, 58.21% (2 088/3 587) exhibited varying degrees of symptoms listed in the SCL-90. Students from families with low per capita income and low parental education level have more prominent psychological problems. The top three stressors perceived were job seeking, research tasks, and self-ability. Students with positive SCL-90 symptoms reported significantly higher perceived stress in all three stressor dimensions compared to their symptom-negative counterparts ( P<0.001), indicating a significant correlation between mental health status and stressors. Conclusions:The mental health status of new professional master's degree graduates in clinical medicine is concerning and warrants focused attention from educational authorities, academic institutions, and families.

Objective:To understand the graduation destination of newly graduated medical master's students in China and analyze their employment status.Methods:A questionnaire survey was conducted on 15 942 medical master's students who graduated in 2023. Descriptive analysis, χ2 test, and Kruskal-Wallis rank-sum test were used to understand the current situation and differences in the graduation destinations, employment units, job positions, and starting salaries of different types of medical master's graduates. Results:The employment rate of medical master's graduates was 58.21% (9 280/15 942). In terms of graduation destinations, male graduates, professional degree holders, graduates from non-"Double First-Class" universities, and nursing majors had a high proportion of confirmed employment units. Male graduates, academic degree holders, graduates from "Double First-Class" universities, and basic medical science majors had a high proportion pursuing further studies domestically. In terms of employment, the highest proportion of medical master's graduates worked in hospitals (84.92%, 6 495/7 648) and the lowest proportion worked in primary-level medical and healthcare institutions (1.02%, 78/7 648). The majority (78.07%, 5 971/7 648) held professional technical positions. Starting salaries were relatively low and ranged between 3 001 and 5 000 yuan/month, accounting for 30.99% (2 370/7 648).Conclusions:The employment rate of medical master's graduates is low, with concentrated employment units and job positions, and there is a lack of talents in primary medical institutions. Colleges and universities and education management departments should adopt policy-driven approaches to support key demographic groups and encourage employment in primary healthcare. Training programs should be timely adjusted in response to market demands and focus on cultivating the comprehensive quality and job competence of medical master's graduates. Additionally, student-centered approaches should be used to strengthen the employment guidance and career planning services.

In order to establish a serological method for the detection of bovine parainfluenza virus type 3(BPIV3),the prokaryotic expression and purification of BPIV3 HN,NP,F,and P proteins were carried out,and the optimal protein-coated antigen was screened,and an indirect ELISA de-tection method was established.The results showed that the four recombinant proteins of BPIV3,rHN,rNP,rF,and rP were expressed,and the checkerboard titration results showed that rHN pro-tein had the highest P/N value as the coating protein,so it was used for the subsequent method es-tablishment.The optimal reaction conditions for indirect ELISA were found to be:the mass con-centration of the antigen coating was 0.5 mg/L,37 ℃ 1.5 h,5％skim milk,overnight blocking at 4 ℃,serum dilution at 1∶50,incubation at 37 ℃ 1 h,secondary antibody dilution at 1∶10 000 and incubation at 37℃ 0.5 h,substrate reaction conditions were 37℃ for 12 min.The results of speci-ficity experiments showed that the established method could specifically identify BPIV3 antibody-positive serum with a sensitivity of 1∶800,and the coefficient of variation in the detection of intra-and inter-assay repeatability was less than 10％,and the overall coincidence rate of the same batch of samples detected with the SVANOVIR kit was 92.22％.This method was used to detect 192 se-rum samples in Hebei Province,and the positive rate of BPIV3 antibody in serum was 66.15％.The indirect ELISA detection method of BP1V3 antibody constructed in this study is suitable for large-scale clinical serological investigations,and provides valuable data support for the research and de-velopment of BPIV3 antigen and antibody detection kits in China.

Human Respiratory Stem Cells (RSCs) play a crucial role in the maintenance, repair and regeneration of the respiratory system. As a novel therapeutic method, stem cell therapy is a popular research direction in the medical field. And with the in-depth research on the mechanism of pneumonia caused by respiratory infections in recent years, the use of RSCs to explore pneumonia caused by respiratory infections and its therapeutic strategies has become a hot topic. In this paper, we firstly outlined the types of RSCs, summarized the mechanism of pneumonia caused by respiratory tract infections, discussed the advantages of RSCs application and the progress of culture differentiation, and elaborated the therapeutic exploration of RSCs in pneumonia caused by respiratory tract infections.