ObjectiveTo summarize the research and manufacturing ideas of precise positioning instrument and its feasibility and safety in the minimally invasive percutaneous nephrolithotripsy.Methods The precise positioning instrument was preliminarily made by integrating ruler with protractor.Fifty cases of kidney stones or upper ureteral stones were recruited in the study.There were 32 males and 18 females with mean age of 47 years (21 -75 years).Of them,6 cases had open surgery history and 31 cases had different degrees of hydronephrosis.The distance from the mid-point of renal pelvis to the plane of the dorsal surface and the distance from the incident point of the mid-point of pelvis on the dorsal surface to spinous process were measured by ruler on the preoperative CT images.According to the measured results,the point,angle,direction and depth of needle were calculated by geometric formula,and then fix position puncture and percutaneous puncture channel expansion were completed by precise positioning instrument and calibrated by Carm X-ray machine.ResultsThe puncture channels were established successfully in all of the 50 cases.Forty-six cases were punctured successfully by just one try,and the success rate of one puncture only was 92.0％.C-arm was used in none of the cases during the channel establishing process.Each patient was Xrayed 1 -3 times,and the average was 1.4 times.Targeting deflection or renal pelvis injury occurred in none of these cases.ConclusionThe application of the homemade precise positioning instrument is a safe and quick method for the establishment of puncture channel during percutaneous nephrolithotripsy,meanwhile the surgeons can reduce the exposure to radiation.

Objective To investigate the effects of D-limonene on the proliferation and ras P21 expression in human bladder carcinoma EJ cell.Methods The cell proliferation was measured by XTT assay.The expression of ras mRNA was detected by real-time PCR,and the expression of its protein product was analyzed by Western Blot.Results The proliferation of EJ cell was inhibited by exposure to 2 mmol/L and 4 mmol/L D-limonene for 48h.The optical density (A) was 0.801±0.016 and 0.148±0.008,respectively.There were significant differences between the experimental groups and the control group (1.2181±0.031,P<0.05).The expressions of ras P21 and its protein product of EJ cell were decreased obviously when exposure to 1 mmol/L of D-limonene for 48h.The expres-sions were significantly different compared with the control group(P<0.05).Conclusions D-limo-nene could inhibit human bladder carcinoma EJ cell proliferation,which is in a dose-dependant man-ner.In a lower dose (<1 mmol/L),D-limonene can decrease the expression of ras mRNA and its protein product.