ABSTRACT
Objective To set up a living mice colonoscopy platform to establish an orthotopic model of colorectal cancer in mice under direct vision,and to observe its biological behavior such as metastasis.Methods Eighteen-week-old male C57/BL mice were anesthetized,and the intestinal lumen of the mice was examined by a self-developed living mice colonoscopy and Olympus URF-P5 ureteroscopy,respectively.The imaging effects of the two methods were compared.Human colon cancer HT-29 cells were injected into the colonic mucosa of BALB/c-nu mice under direct vision.The colonoscopy was performed on the 3rd,7th and 15th day after the injection to observe the tumor formation in the intestinal lumen.The mice were sacrificed when the body weight decreased significantly or cachexia appeared,and then the abdominal cavity was examined including the tumor formation and metastasis.Results The self-developed living mice colonoscopy platform can provide clear vision of enteric cavity,and no mice died in the colonoscopy examination.In vivo subcutaneous injection of HT-29 cells in mice was performed with a perforation rate of 15％,a mortality rate of 33.3％,a tumor formation rate of 62.5％,an abdominal metastasis rate of 60％,a liver metastasis rate of 25％,and an abdominal wall transfer rate of 25％.Conclusion The self-developed mice colonoscopy platform can be used for the study of colorectum in living mice.The imaging effect is no less than that of Olympus URF-P5 ureteroscopy.In addition,an orthotopic colorectal cancer model can be established by this platform combing with submucosal injection technology.
ABSTRACT
BACKGROUND: It can to a certain extent prevent complications during root canal preparation and improve the success rate of root canal therapy by understanding root canal anatomical configuration and bending degree.OBJECTIVE: To investigate the root canal curvature of permanent anterior teeth from Han Chinese people in Shandong province.METHODS: A total of 208 anterior teeth were collected and examined by indirect digital X-ray radiography both from labiolingual and mesiodistal directions,according to Schneider method,the data obtained were analyzed.RESULTS AND CONCLUSION: Most root canals of anterior teeth from Shandong province were typeⅠ,and more than half were curved. The most curvature happened in the apical third. The highest rate of canal curvature occurred in maxillary canines. Except the central incisors,the S-shaped canal was observed on the rest teeth. The radius of mandibular anteriors was obvious longer in labiolingual directions than that in mesiodistal directions. Root canal curvatures of anterior teeth from Shandong province are complex and have a higher bending rate.