BACKGROUND:For the replacement treatment of long-segment tracheal defects,although tissue engineering research has made some progress in recent years,it is still not perfect,and one of the biggest difficulties is that the hemodynamic reconstruction of the tracheal replacement cannot be achieved rapidly. OBJECTIVE:To preliminarily explore the potential of polycaprolactone scaffolds modified with exosome-loaded hydrogels to construct a rapidly vascularized tracheal substitute. METHODS:Exosomes were extracted from bone marrow mesenchymal stem cells of SD rats.After preparation of hyaluronic acid methacrylate solution,the exosome solution was mixed with hyaluronic acid methacrylate solution at a volume ratio of 1:1.Hyaluronic acid methacrylate hydrogels loaded with exosomes were prepared under ultraviolet irradiation for 5 minutes.The degradation of exosome-unloaded hydrogels and the controlled release of exosome-loaded hydrogels were detected.Polycaprolactone scaffolds were prepared by 3D printing.The pure hyaluronic acid methacrylate solution and the exosome-loaded hyaluronic acid methacrylate solution were respectively added to the surface of the scaffold.Hydrogel-modified scaffolds and exosome-modified scaffolds were obtained after ultraviolet irradiation.Thirty SD rats were randomly divided into three groups with 10 rats in each group and subcutaneously implanted with simple scaffolds,hydrogel-modified scaffolds and exosome-modified scaffolds,respectively.At 30 days after surgery,the scaffolds and surrounding tissues of each group were removed.Neovascularization was observed by hematoxylin-eosin staining and Masson staining and the expression of CD31 was detected by immunofluorescence. RESULTS AND CONCLUSION:(1)As time went by,the hydrogel degraded gradually,and the exosomes enclosed in the hydrogel were gradually released,which could be sustained for more than 30 days.The exosome release rate was faster than the degradation rate of the hydrogel itself,and nearly 20%of the exosomes were still not released after 30 days of soaking.(2)Under a scanning electron microscope,the surface of the simple polycaprolactone scaffold was rough.After hydrogel modification,a layer of gel was covered between the pores of the scaffold,and the scaffold surface became smooth and dense.(3)After 30 days of subcutaneous embedding,hematoxylin-eosin staining and Masson staining showed that more neovascularization was observed inside the scaffolds of the exosome-modified scaffold group compared with the hydrogel-modified scaffold group.The hydrogels on the scaffolds of the two groups were not completely degraded.Immunofluorescence staining showed that CD31 expression in the exosome-modified scaffold group was higher than that in the hydrogel-modified scaffold group(P<0.000 1).(4)These results indicate that hyaluronic acid methacrylate hydrogels can be used as controlled-release carriers for exosomes.The 3D-printed polycaprolactone scaffold modified by hyaluronic acid methacrylate hydrogel loaded with exosomes has good biocompatibility and has the potential to promote the formation of neovascularization.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cell Culture Techniques ; methods ; Child ; Female ; Humans ; Induced Pluripotent Stem Cells ; cytology ; metabolism ; Male ; Middle Aged

Virtual reality (VR) is a technology that interacts computer-generated three-dimensional scenes with the user′s senses and has been gradually applied in the real medical field. Since the first time of successful attempt in 3D laparoscopic gastrointestinal surgery VR living video broadcast in 2016, the authors have experienced the exploration of the application of this technology (2016-2017) as well as the in-depth research phase (2018-2019). Nowadays, the VR application in our center has entered into the application practice phase (2020 to present). With the technology iteration and more and more application experience acquisition, our current VR application mainly focuses on two practice settings, including the clinical teaching scenarios for early exposure to acute appendicitis for medical undergraduate students and the preoperative communication to give pati-ents an early sense of the process in the operating theatre, and has achieved good application results. With continuous breakthroughs and innovations in software and hardware, we believe that more clinical VR scenarios and the course audience will be expanded to a wider group. The integration of some new hotspots such as Meta-Universe and ChatGPT will make up for the shortcomings in VR content scenarios and interactivity, and its application prospects are infinite.

Objective:To analyze and summarize the implementation effect of basic essential surgical training (BEST) course of laparoscopic skills over the past 10 years and the practical experience in updating course content and models.Methods:The pre-class assessment questionnaires, basic laparoscopic operation assessment results, and post-class assessment questionnaires of the students who participated in the BEST course of laparoscopic skills were collected. According to the period of the course construction, the students were divided into two groups, namely students who used the course of single training system in the early stage (traditional group) and students who used the course integrating a variety of training systems after the course model was updated in the later stage (test group). The two groups were compared for the scores of track circle moving, tunnel crossing, and high and low columns, as well as their subjective evaluation of course setting and implementation effect. The t-test, Wilcoxon test, or chi-square test was conducted according to the data type using SPSS 13.0. Results:The time for 150 traditional group students to complete track circle moving, tunnel crossing, and high and low columns was 1.08 min (0.81 min, 1.60 min), 2.20 min (1.60 min, 3.27 min), and 4.86 min (3.28 min, 6.36 min), respectively, while the time for 75 test group students to complete the three operations was 1.27 min (0.87 min, 1.83 min), 2.57 min (1.58 min, 4.07 min), and 4.35 min (2.90 min, 6.42 min), respectively, with no significant difference between the two groups ( P>0.05). In terms of students' subjective evaluation of the course, a higher percentage of the test group students were satisfied with classroom environment, teaching method arrangement, training equipment, training opportunities, helping clinical work, and meeting pre-class expectations than those in the traditional group. Conclusion:The constantly updated BEST course can ensure the training quality of trainees and obtain their higher satisfaction. The benefits of this course in clinical practice can be further verified through long-term follow-up of these trainees.

With the continuous development of society and economic activities, ambient air pollution has become an important global environmental and public health issue, and its significant adverse effects on human health have attracted increasing attention. Previous studies have shown a significant association between air pollution exposure and cardiovascular events including cardiac arrest. Although the association between air pollution exposure and risk of cardiac arrest has been identified by several studies, the results remain inconsistent and the pathogenic mechanism is not yet clear. To date, most studies focused on the impact of air pollution exposure on the onset of cardiac arrest, while few studies explored the risk of death from cardiac arrest. Here we reviewed studies investigating the association between short-term exposure to air pollution and risk of cardiac arrest.