This article analyzes the characteristics and current status of orthopedic surgery teaching, as well as the advantages of mixed reality technology. We explore the application of mixed reality technology in the clinical surgery teaching of orthopedics from the perspective of different diseases in orthopedics. Additionally, we analyze its limitations in teaching practice, providing reference for the practical application of mixed reality technology in clinical teaching of orthopedics.

Objective:To study the current status of longitudinal extrauterine growth restriction (EUGR) in extremely preterm infants (EPIs) and to develop a prediction model based on clinical data from multiple NICUs.Methods:From January 2017 to December 2018, EPIs admitted to 32 NICUs in North China were retrospectively studied. Their general conditions, nutritional support, complications during hospitalization and weight changes were reviewed. Weight loss between birth and discharge > 1SD was defined as longitudinal EUGR. The EPIs were assigned into longitudinal EUGR group and non-EUGR group and their nutritional support and weight changes were compared. The EPIs were randomly assigned into the training dataset and the validation dataset with a ratio of 7∶3. Univariate Cox regression analysis and multiple regression analysis were used in the training dataset to select the independent predictive factors. The best-fitting Nomogram model predicting longitudinal EUGR was established based on Akaike Information Criterion. The model was evaluated for discrimination efficacy, calibration and clinical decision curve analysis.Results:A total of 436 EPIs were included in this study, with a mean gestational age of (26.9±0.9) weeks and a birth weight of (989±171) g. The incidence of longitudinal EUGR was 82.3%(359/436). Seven variables (birth weight Z-score, weight loss, weight growth velocity, the proportion of breast milk ≥75% within 3 d before discharge, invasive mechanical ventilation ≥7 d, maternal antenatal corticosteroids use and bronchopulmonary dysplasia) were selected to establish the prediction model. The area under the receiver operating characteristic curve of the training dataset and the validation dataset were 0.870 (95% CI 0.820-0.920) and 0.879 (95% CI 0.815-0.942), suggesting good discrimination efficacy. The calibration curve indicated a good fit of the model ( P>0.05). The decision curve analysis showed positive net benefits at all thresholds. Conclusions:Currently, EPIs have a high incidence of longitudinal EUGR. The prediction model is helpful for early identification and intervention for EPIs with higher risks of longitudinal EUGR. It is necessary to expand the sample size and conduct prospective studies to optimize and validate the prediction model in the future.

Background::Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer associated with poor prognosis and limited treatment options. The androgen receptor (AR) has emerged as a potential therapeutic target for luminal androgen receptor (LAR) TNBC. However, multiple studies have claimed that anti-androgen therapy for AR-positive TNBC only has limited clinical benefits. This study aimed to investigate the role of AR in TNBC and its detailed mechanism.Methods::Immunohistochemistry and TNBC tissue sections were applied to investigate AR and nectin cell adhesion molecule 4 (NECTIN4) expression in TNBC tissues. Then, in vitro and in vivo assays were used to explore the function of AR and estrogen receptor beta (ERβ) in TNBC. Chromatin immunoprecipitation sequencing (ChIP-seq), co-immunoprecipitation (co-IP), molecular docking method, and luciferase reporter assay were performed to identify key molecules that affect the function of AR. Results::Based on the TNBC tissue array analysis, we revealed that ERβ and AR were positive in 21.92% (32/146) and 24.66% (36/146) of 146 TNBC samples, respectively, and about 13.70% (20/146) of TNBC patients were ERβ positive and AR positive. We further demonstrated the pro-tumoral effects of AR on TNBC cells, however, the oncogenic biology was significantly suppressed when ERβ transfection in LAR TNBC cell lines but not in AR-negative TNBC. Mechanistically, we identified that NECTIN4 promoter –42 bp to –28 bp was an AR response element, and that ERβ interacted with AR thus impeding the AR-mediated NECTIN4 transcription which promoted epithelial–mesenchymal transition in tumor progression. Conclusions::This study suggests that ERβ functions as a suppressor mediating the effect of AR in TNBC prognosis and cell proliferation. Therefore, our current research facilitates a better understanding of the role and mechanisms of AR in TNBC carcinogenesis.

Objective: To evaluate the effect of 3DBody software assisted problem-based learning (PBL) teaching in orthopedic teaching. Methods: Undergraduates of clinical medicine from grade 2013 who had internship in our hospital were divided into experimental group and control group. Undergraduates in the experimental group were taught by 3DBody software assisted PBL teaching, with designed questions and the method of using 3DBody software handing to students before class. While undergraduates in the control group were taught by traditional teaching, with the use of textbooks and multimedia courseware. Examination scores of theory and probation were compared between the two groups. Questionnaires were used to evaluate the subjective perception of different teaching method among the participants in each group. Results: Scores of theoretical examination in the experimental group (84.6±5.9) were higher than those in the control group (73.2±6.1); scores of probation examination in the experimental group (17.7±2.1) were significantly higher than those in the control group (12.7±1.9); the degree of satisfaction in the experimental group (9.2±0.8) was significantly higher than that in the control group (7.2±1.3); all differences were statistically significant (P<0.05). Conclusion 3DBody software assisted PBL teaching can significantly improve the effectiveness of orthopedic teaching and enhance students' learning initiative and interest, which is worth promoting.

Objective Analysis of the effect and the mechanism of adenovirus with down regulation of matrix metalloproteinase inhibitor 1 (TIMP-1) achieved targeting by ultrasound microbubbles combined with ultrasound irradiation for liver fibrosis in rats. Methods Recombinant adenovirus-mediated with down regulation of TIMP-1 gene was constructed and a mixture of recombinant adenovirus and ultrasound contrast agent was prepared.The rat liver fibrosis model was established and divided into 5 groups : model group; adenovirus group (recombinant adenovirus); adenovirus microbubble group (mixture of recombinant adenovirus and ultrasound contrast agent); experimental group (ultrasound irradiation + mixture of recombinant adenovirus and ultrasound contrast agent); ultrasound adenovirus group (ultrasound irradiation + recombinant adenovirus). The rats were sacrificed after 24 hours and liver sections were prepared. The expression of EGFP in each group was observed and the transfection rate was analyzed. The liver slices were stained by Masson to judge the stage of liver fibrosis. ANOVA analysis was used to compare the levels of alanine aminotransferase (ALT) , aspartate aminotransferase (AST) , bydroxyproline (Hyp) , hyaluronic acid (HA) , type IV collagen (CIV) and laminin (LN) in each group. The relative expression levels of TIMP-1 and matrix metalloproteinase 13 (MMP-13) in each group were detected by Western blot. Results The transfection rate of the experimental group was higher than that of the adenovirus group (q = 3.418) , the adenovirus microbubble group (q = 3.756) and the ultrasonic adenovirus group (q = 5.502) , and the difference was statistically significant (P < 0.05); Pathological examination showed that the degree of fibrosis in the experimental group and the grade of liver fibrosis were lower than the other groups (P < 0.01). The activities of ALT, AST, HA, LN, CIV and Hyp in the experimental group were lower than those in the other 4 groups.Western blot showed that the level of TIMP-1 protein expression was highest while the level of MMP-13 protein expression was lowest in the experimental group than those in the other groups. Conclusion Adenovirus with down regulation of TIMP-1 achieved targeting by ultrasound microbubbles combined with ultrasound irradiation can inhibit the activity of TIMP-1 and improve the degree of liver fibrosis. Gene therapy is an potential therapeutic method in the application of treating liver fibrosis.

Objective To investigate the effects of disulfiram combined with copper (DSF /Cu) on proliferation and migration of brain metastases from lung cancer. Methods The cell were divided into blank control group, valproate group (1.0 mmol·L-1 of valproate) , DSF /Cu (1,2,3,4,5 mg /0.17 mg) . Brain metastases from lung adenocarcinoma were incubated 72 hours.The changes of proliferative ability of cancer cells were detected by CCK-8 method, the effect of DSF /Cu on the migration ability of cancer cells was detected by Transwell chamber, and the degree of apoptosis of cancer cells was detected by Annexus V-PI double staining method. Results The ability of proliferation was significantly inhibited, the ability of migration was significantly reduced,and the rate of cell apoptosis was significantly increased in each dose group of brain metastases from lung adenocarcinoma compared with the blank control group. With the increase of DSF /Cu dose, its ability to inhibit the proliferation and migration of metastases cancer cells and induce apoptosis of metastases cancer cells has increased gradually. Conclusion DSF /Cu can inhibit the proliferation and migration of brain metastases from lung adenocarcinoma and induce apoptosis. DSF is expected to be a new method of the combined treatment of brain metastases cancer.

Objective To evaluate the combination use of thyroid fine needle aspiration biopsy (FNAB)and V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E gene mutation testing in differentiating benign from malignant thyroid nodules.Methods A total of 64 patients with pathologically-proved thyroid nodules were included in this study.The clinical data,including preoperative ultrasound-guided thyroid FNAB and BRAF V600E gene mutation detection,were retrospectively analyzed.Taking postoperative histopathological results as diagnostic gold standard for the thyroid nodule,the diagnostic values of simple FNAB,simple BRAF V600E gene mutation testing,and combination use of FNAB and BRAF V600E gene mutation detection were separately assessed.Results In the 62 patients a total of 64 nodules were detected (2 patients having bilateral nodules) and treated with surgery.Of the 64 nodules,BRAF V600E mutation was detected in 44 nodules,and 43 nodules were proved to be thyroid papillary carcinoma by postoperative pathological examination.Among the 44 nodules showing BRAF V600E mutation,FNAB made malignant diagnosis in 28,benign diagnosis in 6,and uncertain diagnosis in 10.Of the 20 nodules showing no BRAF V600E mutation,FNAB made malignant diagnosis in 5,benign diagnosis in 3,and uncertain diagnosis in 12.The postoperative pathological examination confirmed that 14 lesions were thyroid papillary carcinoma,4lesions were nodular goiter,one lesion was subacute thyroiditis,and one lesion was thyroid adenoma.Among the 57 thyroid papillary carcinomas,BRAF V600E mutation was detected in 43,with the mutation rate being 75.4％.Compared with the gold standard based on pathological diagnosis,the sensitivity,specificity,positive predictive value,negative predictive value,correct diagnosis rate of FNAB for judging benign or malignant thyroid nodules were 78.9％,85.7％,97.8％,33.3％ and 79.7％ respectively,which of BRAF V600E gene mutation detection for judging benign or malignant thyroid nodules were 75.4％,85.7％,97.7％,30.0％ and 76.6％ respectively,and which of FNAB plus BRAF V600E gene mutation detection for judging benign or malignant thyroid nodules were 94.7％,71.4％,96.4％,62.5％ and 92.2％ respectively.By using McNemar paired data x2 test to compare FNAB with combination use of FNAB plus BRAF V600E gene mutation detection in diagnosing thyroid nodules,the results indicated that statistically significant deference in differentiating benign from malignant thyroid nodules existed between the two methods (P＜0.001).Conclusion For the qualitative diagnosis of thyroid nodules which nature cannot be determined by simple FNAB,FNAB combined with BRAF V600E gene mutation detection can improve the diagnostic accuracy for benign and malignant thyroid nodules.

Objective To explore the efficacy of radiofrequency ablation (RFA) and ethanol ablation(EA) for treating partially cystic thyroid nodules.Methods One hundred and twenty-four patients with a single partially cystic thyroid nodules which caused pressure symptoms or cosmetic problems were treated with RFA (n =42),EA (n =39) or RFA + EA(n =43).The inactivation rate of the nodule,tumor volume reduction rate,symptom scores (0-10) and complications were evaluated before and after treatment.Results The mean inactivation rate of RFA,EA and RFA + EA groups was (87.50 ± 5.77) ％,(57.00 ± 6.12) ％,(90.03 ± 5.39) ％,respectively.The inactivation rate of the nodule was negatively related to the volume of the solid part of the nodule.As to nodules with the volume ranging from 30 to 45 ml,the inactivation rate of RFA group was lower than RFA + EA group.Nodule volume reduction ratio (percentage) at 12-month follow-up was 90.45％ for RFA group,69.88％ for EA group,and 93.28％ for RFA + EA group.Regarding mean volume reduction,there were no difference between RFA + EA and RFA group (P ＞0.05),while there were significant differences between RFA + EA and EA group (P ＜0.05),also RFA and EA group (P ＜0.05).The patients in EA subgroup with cystic part percentage less than 50％ had a unsatisfying outcome (the volume reduction ratio less than 50％),while there were no differences(P ＞0.05) on the volume reduction ratio of nodule based on cystic part percentage between RFA group and RFA + EA group.The rate of the complication was 7.14％,2.56％,2.33％,respectively.Conclusions Ultrasound-guided percutaneous aspiration combined with RF ablation yielded better results than EA ablation.But due to ethanol ablation being less expensive and simpler to perform than RFA,ethanol ablation should be the first line treatment technique for benign thyroid nodules with cystic part percentage more than 50％,while radiofrequency ablation as first-line treatment for benign thyroid nodules with cystic part percentage less than 50％.

OBJECTIVETo explore the relationship between the collision parameters of vehicle and the pedestrian thorax injury by establishing the chest simulation models in car-pedestrian collision at different velocities and angles.

METHODS87 cases of vehicle-to-pedestrian accidents, with detailed injury information and determined vehicle impact parameters, were included. The severity of injury was scaled in line with the Abbreviated Injury Scale (AIS). The chest biomechanical response parameters and change characteristics were obtained by using Hyperworks and LS-DYNA computing. Simulation analysis was applied to compare the characteristics of injuries.

RESULTSWhen impact velocities at 25, 40 and 55 km/h, respectively, 1) the maximum values of thorax velocity criterion (VC) were for 0.29, 0.83 and 2.58 m/s; and at the same collision velocity, the thorax VC from the impact on pedestrian's front was successively greater than on his back and on his side; 2) the maximum values of peak stress on ribs were 154, 177 and 209 MPa; and at the same velocity, peak stress values on ribs from the impact on pedestrian's side were greater than on his front and his back.

CONCLUSIONThere is a positive correlation between the severity and risk of thorax injury and the collision velocity and angle of car-thorax crashes. At the same velocity, it is of greater damage risk when the soft tissue of thorax under a front impact; and there is also a greater risk of ribs fracture under a side impact of the thorax. This result is of vital significance for diagnosis and protection of thorax collision injuries.

Accidents, Traffic ; Adult ; Aged ; Biomechanical Phenomena ; Female ; Finite Element Analysis ; Humans ; Male ; Middle Aged ; Pedestrians ; Stress, Mechanical ; Thoracic Injuries ; etiology ; Trauma Severity Indices

OBJECTIVETo study the biomechanical mechanism of head injuries beaten with sticks, which is common in the battery or assaultive cases.

METHODSIn this study, the Hybrid-III anthropomorphic test device and finite element model (FEM) of the total human model for safety (THUMS) head were used to determine the biomechanical response of head while being beaten with different sticks. Total eight Hybrid-III tests and four finite element simulations were conducted. The contact force, resultant acceleration of head center of gravity, intracranial pressure and von Mises stress were calculated to determine the different biomechanical behavior of head with beaten by different sticks.

RESULTSIn Hybrid-III tests, the stick in each group demonstrated the similar kinematic behavior under the same loading condition. The peak values of the resultant acceleration for thick iron stick group, thin iron stick group, thick wooden stick group and thin wooden stick group were 203.4 g, 221.1 g, 170.5 g and 122.2 g respectively. In finite element simulations, positive intracranial pressure was initially observed in the frontal comparing with negative intracranial pressure in the contra-coup site. Subsequently the intracranial pressure in the coup site was decreasing toward negative value while the contra-coup intracranial pressure increasing toward positive values.

CONCLUSIONSThe results illustrated that the stiffer and larger the stick was, the higher the von Mises stress, contact force and intracranial pressure were. We believed that the results in the Hybrid-III tests and THUMS head simulations for brain injury beaten with sticks could be reliable and useful for better understanding the injury mechanism.

Biomechanical Phenomena ; Brain Injuries ; etiology ; Finite Element Analysis ; Humans ; Intracranial Pressure ; Manikins