Tissue engineering can regenerate damaged tissues and restore the biological functions by cell or tissue reconstruction,and is becoming a promising method for trachea replacement.Seed cells,cell growth factors and tracheal scaffolds are the three major elements of tissue engineering trachea,as a result researchers have paid a lot of attention to find ideal seed cells.Mesenchymal stem cells (MSCs) are a kind of stem cells with high self-renewal ability and muhi-directional differentiation potential.MSCs are widely distributed in bone marrow,umbilical cord,adipose tissue,myocardial tissue,brain,muscle and skin,and can differentiate into a variety of cells,including osteocytes,chondrocytes,adipocytes and neurocytes.MSCs have the characteristics of high proliferation ability,wide differentiation range and immunomodulatory function,which can be used to repair damaged tissue.These advantages make the MSCs an ideal candidate of seed cells for tissue engineering trachea.This review mainly summarized the application of MSCs in tissue engineering trachea.

Objective To prepare 3D printed tracheal graft and investigate its cellular biocompatibility and biomechanical properties.Methods Bone marrow was isolated from tibial plateau of young New Zealand white rabbit,and bone mesenchymal stem cells (BMSCs) were obtained by whole bone marrow culture method and adherent purification method.Biomechanical test was performed for 3D printed trachea graft.After co-cultured of 3D printed trachea graft and BMSCs,cell morphology was observed and the proliferation index of the cells on 3D printed trachea graft was quantified using sulforhodamine B (SRB) assay.Results 3D printed trachea graft showed excellent biomechanical properties.Cell morphology was normal and cells grew well after co-culture with 3D printed trachea graft.The SRB assay indicated good proliferation of BMSCs on 3D printed trachea graft.Conclusions 3D printed trachea graft shows favorable cellular biocompatibility and biomechanical properties,and therefore can be used as a scaffold material for tissue-engineered trachea.

Objective To study the effect of methylprednisolone therapy assisted by direct current field to treat spinal rord injury.Methods In order to make up for the defect that the direct current field could tiol reduce or remove spinal-cord edema,methylprednisolone was used 2 hours after spinal-cord injury.24 Chinese dogs wore randomly divided into two groups.Their spinal cords were made completely injured with Allen method.In Group A the electric stimulator was put into the body directly 6 hours after the spinal cord injury,while in Group B a large dose of rneuiylprednisolone was first injected 2 hours after thf spinal cord injury and then the electric stimulator was put into the body 6 hours after the spinal cord injury.In both groups the nerve function,cortical somatosensory evoked potential and three kinds uf morphometric changes were observed at 1,2,and 3 months after the injury.Results All the indexes mentioned above in Group B were much better than those in Group A.The differences between the two groups were statistically significant.Conclusion The direct current field can promote spinul curd regeneration effectively.A large dose of methylprednisolone assisted by direct current field has synergislic effects in treatment of spinal cord injury,especially in accelerating neurological functional recovery.

In recent years,the incidence of lung cancer,high mortality,become one of the main diseases that threaten human health and life.Preoperative staging of non-small cell lung cancer,especially mediastinal lymph node staging is the key to determine whether surgery and judge tne prognosis of patients.Therefore,how to achieve accurate staging of mediastinal lymph node before surgery is a clinical problem to be solved urgently.The traditional methods of preoperative staging of mediastinal lymph nodes include imaging,minimally invasive biopsy and surgery.In recent years,the development of relevant serum tumor markers,serum miRNAs and clinical prediction models provide some new references for the preoperative diagnosis and assessment of mediastinal lymph node metastasis.This paper reviews the methods of preoperative diagnosis of mediastinal lymph node metastasis of non-small cell lung cancer in recent years,and summarizes and analyzes the advantages and disadvantages of various methods.

In recent years,the detection rate of early lung cancer with microscopic lesions such as ground-glass nodules and sub-centimeter nodules (≤ 1 cm) has been significantly higher.For such lesions,early surgical intervention can effectively prolong the survival time of patients.But in the actual operation of these small lesions difficult to detect,which brought great difficulties to surgery.At present,clinically for such small lesions,usually in the preoperative CT-guided puncture positioning based on the implementation of surgical resection.This method of location there are trauma,complications and other shortcomings,so how to more precise positioning and labeling of lung lesions is a clinical problem to be solved urgently.In this paper,the localization and localization of lung lesions in recent years are reviewed,and the advantages and disadvantages of various methods and materials are summarized and analyzed.

Objective To prepare 3D printed porous tracheal graft fabricated by PCL and to select the appropriate pore size and surface modification techniques,in order to explore its effect on cell behavior.Methods The PCL porous tracheal graft was prepared by 3D printing technology and biomechanical properties of the graft were measured by means of longitudinal tension,radial compression and three-point bending test.The porous grafts were surface-modified through hydrolysis,amination and nanocrystallization treatment and then characterized by energy dispersive spectroscopy(EDS).The effect of different pore sizes and surface modifications on the cell proliferation behavior was evaluated by CCK-8 and scanning electron microscopy (SEM).Results The 3 D printed porous tracheal graft had similar morphology with the native tracheas(P ＞ 0.05) and better biomechanical properties(P ＜0.05).It was more suitable for cell adhesion and proliferation when the pore size is 200 μm (P ＜ 0.05).Compared to hydrolysis and amination,nanocrystallization treatment successfully improved the cytotropism of the 3D printed tracheal graft(P ＜ 0.05).Conclusion 3 D printed porous tracheal graft shows favorable biomechanical properties.The appropriate pore size of the 3D printed porous tracheal graft is 200 μm and the appropriate surface modification techniques is nanocrystallization.

Objective    To investigate the prevalence and related factors of primary palmar hyperhidrosis in adolescents in Yangzhou. Methods    On-site questionnaire survey was performed on students selected by cluster random sampling from the two colleges and two high or middle schools, with each class as a unit. Data were collected through the questionnaire to make the diagnosis and severity grading. Results    A total of 3 487 copies of the questionnaire were distributed in the survey and 3 299 were finished, among which 3 083 were effective with an effective rate of 88.41%. Among them, 1 358 respondents were males and 1 725 were females; 933 were middle school students, 809 high school students, and the remaining 1 341 college students. According to the diagnostic criteria, 104 respondents were diagnosed with palmar hyperhidrosis with an overall prevalence of 3.37%. There were 60 (4.41%) males and 44 (2.55%) females. Although the prevalence of palmar hyperhidrosis in males was higher than that of females (χ2=8.130，P<0.05), severe palmar hyperhidrosis was more often to be observed in females than in males, and females were also more likely to have hyperhidrosis in other parts of the body. In addition, the age of the first onset of the disease was mainly 10 to 20 years old and 36.54% of the patients had a family history. Conclusion    The prevalence of palmar hyperhidrosis in adolescents in Yangzhou was 3.37%, and there is a significant difference in the gender. The palmar hyperhidros is often accompanied by hyperhidrosis symptoms of other parts of body, and the disease shows an obvious genetic predisposition.