Objective To observe the influence of N-myc downstream-regulated gene 2 (NDRG2) on the growth and invasive ability of human colon cancer cell line SW620,and to explore its mechanism.Methods pcDNA3.1-NDRG2 and siRNA-NDRG2 were transfected transiently respectively into SW620 by Lipofectamine TM 2000,untreated cells as the control group.Western blotting was used to investigate the expression of NDRG2 and matrix metalloproteinase-2 (MMP-2).Matrigel invasion assay was used to study the invasive abilities of SW620 cells in all groups.The growth curve was determined through 3-(4,5-dimethyl-2-thiazoly)-2,5-diphenyl-2H-tetrazolium bromide method.Result After transfecting pcDNA3.1-NDRG2 into the SW620 cells,the protein level of NDRG2 increased and the expression of MMP-2 declined markedly.After transfecting siRNA-NDRG2 into the SW620 cells,the protein level of NDRG2 declined and the expression of MMP-2 increased markedly.In addition,compared with the control group (75.80 ± 4.82),the numbers of transmembrane cells in pcDNA3.1 group (56.20 ± 7.40) and in siRNA group (94.20 ± 9.23) were significantly different (t =13.102,P =0.000;t =11.820,P =0.000).The growth curve showed that:compared with the control group (0.67 ±0.01),the absorbance of the fifth day after transfection in pcDNA3.1 group (0.46 ±0.01) and in siRNA group (0.91 ± 0.02) were different significantly (t =9.561,P =0.000;t =10.922,P =0.000).Conclusion NDRG2 can reduce the invasion and proliferation ability of colon cancer cell SW620,and its mechanism may be related to the down-regulation of MMP-2 expression.

Objective To observe if subclinical lesion exists during and after tibia lengthening and investigate the repair mechanism of the nerve. MethodsTwenty-three cases(with 42 tibia) were lengthened by traction with the velocity of 1mm/d. The somatosensory evoked potentials (SEP) induced by stimulation of tibial nerve were recorded before operation and 2,3 months and 2 years after operation. The tibia was lengthened for a total of 4～10cm. ResultsAll cases had no significant symptoms except for 1 case with mild symptoms of nerve lesion when his tibia was lengthened for 9.5cm. However, the subclinical lesion was found by SEP record in all the cases, and this lesion could be repaired mostly in 3 months and completely recovered in 2 years. ConclusionThe peripheral nerves have good adaptability to tibia lengthening with a velocity of 1mm/d and the tibia could be lengthened to a great extend as long as there were no clinical symptoms manifestated.

AIM: The effects of BDM on isolated rat heart in cold cardioplegia were studied METHODS: Rat heart were subjected to cold cardioplegia at 4℃ for 8, 18 and 24 h Then each heart was perfused (90 cm H 2O) in Langendorff model at 37℃ for 40 min In the high K + group( n =24) the hearts were preserved in St Thomas cardioplegic solution, in BDM group( n =24) hearts were preserved in K-H solution with BDM 30 mmoL/L RESULTS: After 18 h, heart rate and the coronary flow in BDM group were significantly higher than in high K + group( P

AIM: To study the effect of thyroid hormone on the expressional change of myosin heavy chain(MHC) gene in cardiomyocyte induced by angiotensinⅡ(AngⅡ) and its potential mechanism. METHODS: Cardiac myocyte was cultured according to the method of Simpson. 10 -8 mol/L T_3 and 10 -7 mol/L AngⅡ were added to the culture medium,respectively or synchronously. After 48 h,the expression of ? and ?-MHC mRNA in myocytes were detected by RT-PCR. The protein kinase C activation were detected by PepTag non-radioactive PKC assay. The incorporation of -Leucine and -thymine to test the protein and DNA synthesis in myocytes were also performed. RESULTS: AngⅡalone increased the incorporation of -Leucine of myocytes while it had no effect on the incorporation of -thy mine. The expression of ?-MHC mRNA was increased and the expression of ?-MHC mRNA was decreased significantly at the condition of AngⅡ. The enhanced PKC activation was induced by AngⅡalso. When AngⅡand T_3 were added to the culture medium synchronously,though the incorporation of -leucine and -thymine were not changed compared with AngⅡ treated alone. The ?-MHC mRNA expression was increased and the ?-MHC mRNA expression was decreased significantly. The PKC activation of the myocytes also was decreased. CONCLUSIONS: T_3 inhibited the expressional change of myosin heavy chain gene in cardiac myocytes induced by AngⅡ. The effect of T_3 on the change of PKC activation in cardiac myocytes may be one of its mechanisms.

Objective To study the optimal laparoscopic procedure and its indication for remove of common bile duct stone. Methods Analysis was made on the clmical data of 124 cases of laparoscopic choledocholithotomy and T tube drainage in our center.Results 82 patients underwent the improved laparoscopic procedure, alternation to open operation in 4 cases (4.9%),and the mean operating time was (80?30) min. While 42 patients were operated with traditional laparoscopic method,changing to open operation in 6 cases (14.3%),and the mean operating time was (170?40) min . The improved method could shorten the operation time and reduce the open operation rate significantly than traditional method did (P