In order to study the relationship between Staphylococcal nuclease(SNase) and diabetes mellitus,genetic engineering bacteria E.coli BL21/pET28a-His-SNase was constructed,the expression of soluble extracellular protein SNase was induced and the a preliminary research was made on it.An expression vector pET28a-His-SNase plasmid containing the His-SNase gene was constructed and transformed into E.coli BL21 (DE3) competent cells.The protein was induced by lactose and purified by ultrasound destruction and Ni-affinity chromatography,respectively.It was then analyzed by SDS-PAGE and Western blot.The enzymatic properties for SNase has been preliminary studied as well.Results indicated that the purity of the correctly expressed fusion protein HisSNase was over 85％.SNase showed good activity within a wide range of pH and good heat resistance.This experiment might be a foundation work for the further study on the relationship between SNase and with diabetes.

Objective To investigate the clinical efficacy and safety of preoperative hypofractionated and conventionally-fractionated chemoradiotherapy for thoracic esophageal cancer. Methods A total of 86 patients with thoracic esophageal cancer receiving chemoradiotherpy in Sichuan Cancer Hospital between 2002 and 2011 were enrolled and randomized into the preoperative hypofractionated chemoradiotherapy group ( group A, n=41, 30 Gy in 10 fractions for 2 weeks ) and conventionally-fractionated chemoradiotherapy group ( group B, n=45, 40 Gy in 20 fractions for 4 weeks ) . Surgery was performed at 2-6 weeks after chemoradiotherapy. The probability of patients' survival was estimated by Kaplan-Meier method and analyzed by log-rank test. Results In groups A and B, the pathological downstaging rates were 68％ and 56％( P=0. 270) , the R0 resection rates were 95％ and 89％( P=0. 437) and the pCR rates of 32％ and 24％( P=0. 480).The 1-,3-and 5-year overall survival (OS) rates were 78％ and 69％,44％ and 44％,29％ and 33％(P=0. 114,0. 223,0. 289), and the progression-free survival (PFS) rates were 71％ and 62％,39％ and 38％,24％ and 29％(P=0. 211,0. 689,0. 331), respectively. The incidence rate of chemoradiothery-and surgery-related adverse events did not differ between two groups (P=0. 089-0. 872).The average length of hospital stay, radiotherapy cost and preoperative treatment costs in group A were significantly less compared with those in group B (P=0. 000,0. 000,0. 000). Conclusions Both preoperative hypofractionated and conventionally-fractionated chemoradiotherapy can be used as the regimen of preoperative chemoradiotherapy in patients with resectable thoracic esophageal carcinoma. Compared with conventionally-fractionated chemoradiotherapy, preoperative hypofractionated chemoradiotherapy has shorter treatment cycle, shorter length of hospital stay and lower radiotherapy cost, which is more easily accepted by patients.