Objective To evaluate the characteristics of abdominal aorta wall motion in different stages of rats atherosclerosis with velocity vector imaging (VVI) technique. Methods Twenty-four healthy SD rats were on high-fat feeding after one week ordinary diet. Abdominal aortic intima-media thickness (IMT), end-systolic blood vessel diameter (Ds), peak systolic velocity (Vs), resistance index (RI), pulsatility index (PI) were measured before and at the end of 8th and 12nd week. Artery wall peak velocity (V_(max)), maximum tangential strain (S_(max)) and the maximum tangential strain rate (SR_(max)) were caculated with VVI. Results Abdominal aortic intima was rough and a small amount of foam cells were found under the light microscope at the end of 8 weeks of high-fat feeding. The values of Smax and SRmax measured at the end of 8th week of high-fat feeding decreased significantly than those of before high-fat feeding (P<0.05). At the end of 12nd week, abdominal aortic intimal was thicker and atherosclerotic plaque appeared somewhere. There were significant differences in artery IMT, Ds, Vs, RI, PI between before and the end of 2nd week of high-fat feeding (P<0.05);the values of V_(max), S_(max), SR_(max) decreased significantly than those of before and at the end of 8th week of high-fat feeding (P<0.05). Conclusion VVI can quantitatively evaluate the vessel wall elasticity in different stage of arteriosclerosis rats.

Objective:To observe and analyze the application effect and value of problem based learning (PBL) combined with team-based learning(TBL) in the teaching of New Drug Clinical Research. Methods:Postgraduate students were randomly divided in-to two groups(n=20):"PBL+ TBL" group and lecture based learning(LBL) group. After the end of the teaching,the teaching ef-fectiveness survey and theory test of the groups were performed,and the results were compared. Results:The combined teaching meth-od (PBL+TBL) could stimulate learning enthusiasm, improve learning efficiency, and enhance the abilities of self-study, literature retrieval and analyzing and solving problems. Totally 90% of students thought the new teaching method had good application value in clinical teaching. Furthermore,the excellent rate of the theory test scores in the combined teaching group was better than that in the traditional teaching group (P<0.05). Conclusion: PBL combined with TBL can overcome the disadvantages of traditional teaching method,which provides higher interest,improved ability of self-study as well as higher teaching quality of medical students. The meth-od is worthy of promotion in postgraduate teaching.

Objective: To access the effect of maternal cell contamination (MCC) on the detection of copy number variation (CNV) by chromosome microarray analysis (CMA) in prenatal diagnostic samples. Methods: Amniotic fluid DNA samples were collected from Department of Prenatal Diagnosis (Screening) Centre of Hangzhou Women′s Hospital from December 2016 to August 2018. Copy number variations (CNVs) were identified in these DNA samples by CMA and normal female genomic DNA was added to simulate different proportions of maternal cells contamination. The simulated samples were tested using an Agilent microarray chromosome chip 180K CGH (Agilent 180K CGH) and the results were analyzed by Agilent CytoGenomics software. Results: The results showed that duplications of CNV could not be detected at>38.4% MCC. Deletions of CNV could not be detected at>41.3% of MCC. With the increase of MCC ratio, the detection rate of CNV decreased gradually. The array and software allowed detection of longer copy-number variations at higher levels of maternal cell contamination than shorter copy-number variations. For the same size CNV, the detection ability of the deleted CNV was slightly higher than that of duplication. In the male sample, the observable shift of the X/Y chromosome ratio at>10% MCC can be detected by the microarray. Conclusions When the MCC is higher than a particular ratio, it can affect the CMA detection of CNV. Based on the Agilent 180K CGH detection results for MCC mimics and the CNV detection specificity principle, the MCC threshold of the Agilent 180K CGH is set to 30% in view of conservative principles.