Objective : To observe the clearance of smear layer on the root canal wall in different action time by scanning electron microscope (SEM), and to determine the optimal amount of time using sonically activated irrigation to wash root canal in clinic. Methods: Fifty-six ex vivo human anterior teeth with single straight root canal were selected. After routine mechanical preparation, they were divided into two experimental groups according to different irrigating agents: saline group and EDTA group. Each group was assisted by VDW sonic activation EDDY. The saline group was divided into three subgroups according to the irrigating time: 5 s, 30 s and 50 s; EDTA group was divided into six subgroups according to the irrigating time: 5 s, 10 s, 20 s, 30 s, 40 s and 50 s. The control group did not undergo root canal irrigation. After irrigation, the root was cut longitudinally. The smear layer of crown, middle and apical of root canal wall was observed by SEM. Results: After irrigating for 30 seconds, there was a significant difference between the normal saline group and the control group and the 5 second group (P<0.05), and there was no difference in the middle and apical part (P>0.05). After 50 seconds, there was a significant difference in the score of the smear layer between the apical area and the other groups (P<0.05). After irrigating for 5 seconds or 10 seconds in EDTA group, there was a significant difference between the scores of the crown and middle area of the root canal and the control group (P<0.05), and there was no significant difference in the apical area (P>0.05). There was a significant difference between the 20-40 second group and the first two groups (P<0.05). There was a significant difference between the 50 second group and the other groups (P<0.05). Comparing the cleaning effect on the smear layer after 50 seconds of irrigating between the two experimental groups, the whole root canal showed significant statistical difference (P<0.05). Conclusion The EDTA-assisted sonic activated device used for 50 seconds has the best cleaning effect.

To compare the performance of ArcCheck and film verification for volumetric intensity modulated arc therapy (VMAT) in the treatment of nasopharyngeal carcinoma, and to study the feasibility of ArcCheck in VMAT dosimetric verification. Five patients of nasopharyngeal carcinoma treated with VMAT were enrolled in this study. Dose verification was carried out by ArcCheck and film respectively. The result showed that there were no significant differences between ArcCheck and film verification. ArcCheck software can obtain three dimensional dose distribution directly with simple operation. It is convenient for ArcCheck to be used for VMAT dosimetric verification.
Carcinoma ; Humans ; Nasopharyngeal Neoplasms ; radiotherapy ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; Software

Objective To investigate the predictive factors for central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma(PTMC).Methods A retrospective study including 2511 cases of PTMC admitted from Jan.2013 to Jan.2016 were enrolled in our study.Chi-square test was used in univariate analysis.Logistic regression analysis was applied for multivariate analysis.The relation between age,sex,tumor size,multifocality,thyroidal extension,nodular goiter and central lymph node metastasis is analyzed.Results Univariate analysis showed that age,sex,tumor size,multifocality,thyroidal extension and nodular goiter had statistical significance.Age less than 45(P＜0.001,x2=17.442);Male gender(P＜0.001,x2=17.029);Tumor size less than 5 mm (P＜0.001,x2=70.164.);Extrathyroid extension factor (P＜0.001,x2=63.197);Nodular hyperplasia factor (P=0.017,x2=5.611).Multivariate analysis showed there was a significant relationship between multifocality and the central lymph node positivity.The odds ratio (OR) was 1.587 in patients with tumor foci ≥2(P＜0.001).While OR increased sharply near to 3 in patients withtumor foci ≥3(OR=2.730).Tumor size(OR=1.926);Extrathyroid extension(OR=1.606).Conclusions Multifocalty,tumor size and thyroidal extension are the main predicative factors for central lymph node metastasis in PTMC.Among them,tumor foci ≥ 3 is an important predictor.Besides the conventional factors such as tumor size,thyroidal extension etc,multifocalty should also be taken into consideration.

【Objective】 To explore the establishment methods of transgenic human umbilical cord mesenchymal stem cells (hUC-MSCs) overexpressing tumor necrosis factor(TNF)-related apoptosis-inducing ligand (TRAIL) based on the transposons, and attempt to apply it on the nude mice mode with glioma. 【Methods】 PiggyBac transposon system specially designed by us was used to prepare non-targeting and Her2-targeting hUC-MSCs that can stably express TRAIL through puromycin screening. The glioma cells expressing firefly luciferase (U87MG-LUC) were injected into the skull of the immunodeficient mice (BALB/c-nu/nu) with 1×10⁶ cells per mouse. After 7 days of injection, the mice transplanted with U87MG were detected with a small animal living imager to determine the size and location of the tumors in skull. Then we injected the glioma-transplantation nude mouse with two kinds of transgenic hUC-MSCs expressing TRAIL (named as untarget-TRAIL and target-TRAIL, respectively), or the non-transgenic hUC-MSCs (all 1×10⁶ cells per mouse) or PBS (named as WT-MSCs and PBS for negative control) respectively, and then monitored the changes of tumor signals by a small animal living imager every week for 3~4 weeks. 【Results】 After six passages to expand the cells, the both transgenic cell lines can stably express TRAIL gene. Their ratio of green fluorescent protein (GFP) positive cells can reach 93%-97%, and the positive ratio of their MSC-specific surface markers still maintained normal (CD34⁺, CD45⁺, and HLA-DR⁺ all <0.1%, CD90>99%, CD73>88%, and CD105 >60%). The median survival time (d) of U87MG-transplanted nude mice in the groups of untarget-TRAIL, target-TRAIL, WT-MSCs, and PBS was 41 vs 39 vs 24 vs 23(P<0.05). 【Conclusion】 The transgenic hUC-MSCs overexpressing TRAIL gene can significantly prolong the survival time of nude mice with brain glioma.