BACKGROUND:Neuregulin 1 has been shown to be characterized in cell proliferation,differentiation,and vascular growth.Human amniotic mesenchymal stem cells are important seed cells in the field of tissue engineering,and have been shown to be involved in tissue repair and regeneration. OBJECTIVE:To construct human amniotic mesenchymal stem cells overexpressing neuregulin 1 and investigate their proliferation and migration abilities,as well as their effects on wound healing. METHODS:(1)Human amniotic mesenchymal stem cells were in vitro isolated and cultured and identified.(2)A lentivirus overexpressing neuregulin 1 was constructed.Human amniotic mesenchymal stem cells were divided into empty group,neuregulin 1 group,and control group,and transfected with empty lentivirus and lentivirus overexpressing neuregulin 1,or not transfected,respectively.(3)Edu assay was used to detect the proliferation ability of the cells of each group,and Transwell assay was used to detect the migration ability of the cells.(4)The C57 BL/6 mouse trauma models were constructed and randomly divided into control group,empty group,neuregulin 1 group,with 8 mice in each group.Human amniotic mesenchymal stem cells transfected with empty lentivirus or lentivirus overexpressing neuregulin-1 were uniformly injected with 1 mL at multiple local wound sites.The control group was injected with an equal amount of saline.(5)The healing of the trauma was observed at 1,7,and 14 days after model establishment.Histological changes of the healing of the trauma were observed by hematoxylin-eosin staining.The expression of CD31 on the trauma was observed by immunohistochemistry. RESULTS AND CONCLUSION:(1)Human amniotic mesenchymal stem cells overexpressing neuregulin-1 were successfully constructed.The mRNA and protein expression of intracellular neuregulin 1 was significantly up-regulated compared with the empty group(P<0.05).(2)The overexpression of neuregulin 1 promoted the migratory ability(P<0.01)and proliferative ability of human amniotic mesenchymal stem cells(P<0.05).(3)Human amniotic mesenchymal stem cells overexpressing neuregulin 1 promoted wound healing in mice(P<0.05)and wound angiogenesis(P<0.05).The results showed that overexpression of neuregulin 1 resulted in an increase in the proliferative and migratory capacities of human amniotic mesenchymal stem cells,significantly promoting wound healing and angiogenesis.

BACKGROUND:At present,there is still controversy in clinical practice about the choice of internal fixation of Pauwels type Ⅲ femoral neck fracture,and the selection of internal fixation that provides stable fixation strength is the key basis for achieving Pauwels type Ⅲ fracture fixation. OBJECTIVE:The three-dimensional finite element analysis method was used to test the difference in biomechanical strength of three types of internal fixation in Pauwels type Ⅲ femoral neck fracture,which provided a reference for its clinical treatment. METHODS:Using the CT data of the left femur of a healthy male volunteer,a complete femur and its cancellous bone were reconstructed in Mimics software,and Geomagic studio software was used for reverse modeling.Cannulated compression screw,dynamic hip screw,and femoral neck system were created in UG-NX software.Three kinds of internal fixation models were assembled on the femur model,and Pauwels type Ⅲ femoral neck fracture was simulated by Hypermesh software.Finally,Abaqus software was used to carry out finite element experimental analysis to analyze and compare the stress distribution,stress peak,strain,and displacement distribution caused by fixed femoral neck fracture of different internal fixation systems. RESULTS AND CONCLUSION:(1)The stress of the proximal femur bone mass was mainly distributed in the area below the femoral neck near the fracture end,with the highest stress peak in the dynamic hip screw group and the smallest in the femoral neck system group.(2)The stress distribution of the internal fixation device was mainly concentrated on the screw surface near the fracture line,with the highest stress peak in the femoral neck system group and the smallest in the dynamic hip screw group.(3)The main strain field of the proximal femur bone mass was distributed in the upper surface area where the bone and screw contacted,and the yield strain was the smallest in the femoral neck system group and the largest in the cannulated compression screw group.(4)The main strain field of the internal fixation device model was distributed on the upper surface of the femoral neck screw,with the yield strain being the smallest in the femoral neck system group and the largest in the cannulated compression screw group.(5)The displacement distribution values of femur,proximal bone mass,distal bone block,internal fixation device and internal fixation with the femur as a whole in the three femoral neck fracture internal fixation models decreased gradually from proximal to distal,and the peak displacement of the femoral neck system group was the largest and the lowest in the dynamic hip screw group.(6)The results showed that when the Pauwels type Ⅲ femoral neck fracture was fixed,the stress distribution of femoral neck system was more uniform,the mechanical conduction characteristics were better,and it was subjected to lower yield strain,higher stress and higher displacement.It has relatively better biomechanical stability and can provide a superior mechanical environment for fracture healing.

Objective:To investigate the potential risk factors of the tumor abnormal protein (TAP) in papillary thyroid carcinoma (PTC) and analyze the clinical significance of TAP.Methods:The clinical data of 792 patients who underwent thyroid surgery in the thyroid surgery department of the First Affiliated Hospital of Zhengzhou University from Jun. 2018 to Jun. 2019 was collected, of whom 564 were PTC patients and 228 were benign thyroid tumor patients. Patients were divided into two groups by postoperative pathology: PTC group and thyroid benign tumor group. The potential risk factors the TAP in PTC were analyzed by univariate and multivariate Logistic regression analysis, and then the diagnostic value of TAP for PTC was assessed by ROC curve analysis.Results:Multivariate analysis showed that tumor maximum diameter (≥1.0 cm) ( OR:1.555; 95% CI: 1.031~2.344, P=0.035) and multifocal tumor ( OR:1.789; 95% CI: 1.098~2.916, P=0.019) were risk factors for elevation of TAP. Gender, age, body weight, extracapsular extension of cancer, invasive growth of cancer, Hashimoto's thyroiditis, central lymph node metastasis, lateral lymph node metastasis, and BrafV600E mutation were not associated with TAP ( P>0.05) . TAP in patients with PTC was significantly higher than that in patients with benign thyroid tumors[ (122.36±49.37) μm 2 vs (105.04±40.61) μm 2, P<0.001]. The sensitivity and specificity of TAP in diagnosing PTC were 78.90% and 40.35%, respectively. Conclusions:Tumor maximum diameter (≥1.0 cm) and multifocal tumor in PTC were risk factors for elevation of TAP. TAP has certain clinical value in differentiating PTC and thyroid benign tumor, which could be used as an auxiliary indicator.

Objective To set up a standardized examination system for clinical internship at the de-partment level, and to evaluate the system using educational measurement method. Methods All the 327 clinical five-year and eight-year intern trainees who took clinical internship in the spinal orthopedics de-partment of a teaching hospital from July 1, 2014 to June 30, 2016 were selected as the research subjects. All the subjects took the standardized examination, educational and measurement methods such as general descriptive analysis, project relevance analysis and grader consistency analysis were executed to assess the content validity of the system, the relevance of the project and the consistency of the scorers. Statistical calculation was executed by SPSS 23.0 software. Results The average score of all 312 trainees included was controlled at (80.07±4.67), the lowest score was 70.01, and the highest score was 90.01, which reflected that the overall difficulty was moderate, the difference was reasonable and the scores were evenly distributed. To the theory, skills, medical records, teachers' score and the reward plus, normalized regression coeffi-cients were 0.479, 0.473, 0.118, 0.135 and 0.364 respectively, which were in good agreement with the scores of each item in the total score. To the theory, skills and teacher evaluation, the analysis of variance of the total score showed that the P values were both ≥0.05 with no significant difference between the groups, so the consistency of the scorers were satisfactory. The P values of variance analysis of the two items of the medical record and bonus points were 0.000 and 0.002 respectively, with significant differences among the groups, the scorers were less consistent. Conclusion The standardized examination system can meet the requirements of comprehensive, full-scale, quantitative and stable feedback teaching effect. The system of internship practice examination must be able to withstand continuous implementation and repeated correc-tion over many years, so as to ensure the teaching quality.

ObjectiveTo investigate the genetic polymorphisms of 21 short tandem repeat(STR)loci (D3S1358, D13S317, D7S820, D16S539, Penta E, D2S441, TPOX, TH01, D2S1338, CSF1PO, Penta D, D10S1248, D19S433, vWA, D21S11, D18S51, D6S1043, D8S1179, D5S818, D12S391 and FGA). Methods A total of 560 blood samples were collected from unrelated healthy individuals of Han population in Hunan Province. Chelex-100 extraction method was applied to the extraction of genomic DNA, and an AGCU EX22 Kit and 9700 STR amplification was used in amplification reactions. The products were separated and analyzed on 310 Genetic Analyzer.ResultsA total of 248 alleles were observed, the al-lelic frequencies ranging from 0.001 to 0.518. Observation of genotype distributions for each locus showed no deviations from Hardy-Weinberg equilibrium exceptPentaE(P=0.023). The combined pow-er of discrimination, combined power of exclusion, and combined matching probability of the 21 STR loci were approximately 0.999 999 999 999 999 999 999 999 8, 0.999 999 998, and 1.36×10-25, respectively. ConclusionThe 21 STR loci show high polymorphisms in the Han population, which can provide valu-able data and a theoretical basis for forensic individual identification and paternity testing.

Clinical tutor system is a unique exploration and practice with characteristics of our school,which has been carried out in the process of clinical course learning and clinical practice among eight-year-program clinical majors.Through analyzing and summarizing the implementation among 2005 and 2006 grade students,we found that the clinical tutor played an active role in cultivating students' clinical thoughts and personal ethics and in improving clinical ability and scientific ability.However,some problem were existed in tutors themselves-specialized major,busy,unclear cultivation objective,etc.Therefore,further improvement of the system was needed in order to better meet the needs of the eight-year-program medical talent training and to provide related references.

Objective To measure the in vitro antibacterial activity of tigecycline against carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex.Methods The isolated strains of carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex were collected in our hospital from December 2013 to February 2014.The MIC test strip was a-dopted to measure the MIC value of tigecycline.The break point adopted the judgment criteria published by FDA.Results All 61 strains of carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex had extremely high drug resistant rate to the commonly used antimicrobial agents.The sensitive rate of tigecycline was 80.3%,intermediation was 19.7% and no re-sistant strain was found in this study.MIC50 and MIC90 were 2 μg/mL and 3 μg/mL respectively.Conclusion Tigecycline has bet-ter in vitro antibacterial activity to the carbapenems-resistant Acinetobacter calcoacetcus-Acinetobacter baumannii complex isolated in our hospital.

The authors of this paper confirm the goal, factors and principles in arrangement of clinical practice, design a transplacement algorithm to solve the model, and after estimating the capacity to interns of affiliated hospital, make the schedule by that algorithm so as to relieve the relative short supply of good clinical education resourses.

A questionnaire survey was conducted among undergraduate international students to investigate the effects of stomatology teaching.The effects of stomatology teaching had been proved to be fair, while some shortcomings had also emerged. In further teaching adjustments have to be made to teaching plans and teachers' Enghsh abilities are expected to be improved.

In order to investigate the application of standard score in the examination of eight-year program's clinical practice and to keep consistency of learning level among groups, we translate the original scores into standard scores and discuss the results and how to define the excellent grade so that the scores may have more comparability.