Recently, the integrated medical curriculum with main line of organ system and with core of disease has played an important role in medical educational reform. During the teaching reform of ultrasonic imaging in the First Affiliated Hospital of Chongqing Medical University, there existed some main problems: simply considering the "integration" as "combination"; unreasonable arrangement of ultrasonic courses; different emphasis on teaching goals between the traditional and integrated teaching; deficient ultrasonic knowledge of clinical teachers, etc.. To solve those problems, teachers participated in the reform must take some measures: firstly, totally understand the spirit of integrated medical reform, and the goal of reform which is improving the clinical ability and quality of medical students but not the pure teaching of medical knowledge; secondly , adjust the curriculum establishment and content of ultrasonic imaging;thirdly, fully utilize the Picture Archiving and Communication System (PACS) system to complement the problem of deficient ultrasonic knowledge of clinical teachers.

Objective:To develop an efficient and rapid method for the isolation and cultivation of human scalp dermal papilla cells from small specimens.Methods:Hair-bearing skin specimens measuring 0.5 cm × 0.5 cm -0.5 cm × 1 cm in size were obtained from the scalp of 3 patients with pigmented nevus and 6 with sebaceous nevus during surgery in Department of Dermatology, the First Hospital Affiliated to Army Medical University from September 2018 to January 2019. The subcutaneous fat layer containing hair follicles was cut out of the specimens, and hair follicles were sorted with ophthalmic forceps, which were subsequently digested with 0.6% dispase Ⅱ for 30 minutes, then with 0.2% collagenase Ⅳ at 37 ℃ for 30 - 60 minutes, and were centrifuged to obtain hair papillae. Morphological observation was performed on the isolated hair papillae, and dermal papilla cells were cultured, passaged and identified.Results:Under the microscope, the hair papillae isolated by two-step enzyme digestion of small scalp specimens were intact, and showed an inverted pear-like shape, and residual dermal sheaths could be observed around some hair papillae. However, no hair papilla was isolated by one-step enzyme digestion. With the two-step enzyme digestion method, the hair papilla separation rate was 60.8% ± 2.1%, the adherence rate of the dermal papilla cells at 72 hours was 86.6% ± 3.9%, the time for cells to emigrate out of hair papillae was 0.5 - 3.0 days, the total operation duration was 2.0 - 3.0 hours, and the actual operation duration after subtraction of digestion duration was 1.0 - 1.5 hours. The dermal papilla cells isolated by the two-step enzyme digestion method could grow in an aggregative pattern in early stage, but grew in a non-aggregative pattern after 8 passages.Conclusion:The two-step enzyme digestion of small specimens is a simple and efficient method for isolating human scalp dermal papilla cells.

Objective To investigate an efficient rapid method for the isolation and cultivation of human axillary dermal papilla cells.Methods Skin specimens with hair follicles were obtained from the axillary area of patients who received bromhidrosis surgery in the Department of Dermatology of the First Affiliated Hospital to Army Medical University from October 2015 to May 2016.The axillary dermal papilla cells were isolated by two-step enzyme digestion method,one-step digestion method and micro-dissection method separately.Then,axillary dermal papilla cells were cultured and identified.Differences in the operative procedure,separation efficiency and adhesion efficiency of dermal papilla cells,cell emigration duration,total operation duration and actual operation duration were compared among the above 3 methods.Results Compared with the one-step digestion method and micro-dissection method,the two-step enzyme digestion method showed simpler operative procedure,more than 30％ separation rate and 96％ adhesion rate of dermal papilla cells after 1 week.Moreover,the cell emigration duration was shortened by 3-4 days by the two-step enzyme digestion method.The two-step enzyme digestion method also showed longer total operation duration,but shorter actual operation duration compared with the one-step digestion method and micro-dissection method,as well as lower contamination rate compared with the micro-dissection method.Cultured axillary dermal papilla cells grew in an aggregative pattern in the early stage,but grew in a nonaggregative pattern after 6 passages.Immunofluorescence assay showed positive staining for laminin and collagen Ⅳ in axillary dermal papilla cells.Conclusion The modified two-step enzyme digestion method is a kind of simple,efficient and rapid method for the isolation of human axillary dermal papilla cells,and axillary dermal papilla cells can be harvested through this method by using a few specimens.

Objective:To investigate the application value of WeChat-based problem-based learning teaching method combined with micro-classroom in the teaching of contrast-enhanced gastrointestinal ultrasound imaging for residents in standardized residency training.Methods:A total of 40 trainees who underwent the standardized residency training in the Department of Ultrasound, The First Affiliated Hospital of Chongqing Medical University from January 2019 to June 2021 were selected as the research objects. They were randomly divided into the experimental group (WeChat-based PBL teaching method combined with micro-classroom) and the control group (traditional teaching method). The teaching content was the diagnosis of gastrointestinal ultrasound imaging. After the theoretical learning and practice, assessments of contrast-enhanced gastrointestinal ultrasound imaging including theory and operating practice were performed to all students. SPSS 22.0 was used for t test and rank sum test.Results:After training, the theoretical test scores of the experimental group were higher than those of the control group [(93.09±2.31) vs. (90.63±2.26)], and the difference was statistically significant ( P<0.05). However, there was no significant difference between the two groups in the number distribution of students at all levels of operational practice ( P>0.05). Conclusion:The WeChat-based PBL teaching method combined with micro-classroom is beneficial to improve students' knowledge of contrast-enhanced gastrointestinal ultrasound imaging, and is worth being popularized and applied in clinical teaching.