Preoperative colonoscopy through the colonic stent in patients with colorectal cancer obstruction

AIM:To evaluate the feasibility of a preoperative colonoscopy through a self-expendable metallic stent(SEMS)and to identify the factors that affect complete colonoscopy.METHODS:A total of 48 patients who had SEMS placement because of acute malignant colonic obstruction underwent preoperative colonoscopy.After effective SEMS placement,patients who showed complete resolution of radiological findings and clinical signs of acute colon obstruction underwent a standard bowel preparation.Preoperative colonoscopy was then performed using a standard colonoscope.If the passage of colonoscope was not feasible gastroscope was used.After colonoscopy,cecal intubation time,grade of bowel preparation,tumor location,stent location,presence of synchronous polyps or cancer,damage to colonoscopy and bleeding,and stent migration after colonoscopy were recorded.RESULTS:Complete evaluation with colonoscope was possible in 30 patients(62.5%).In this group,adenoma was detected in 13 patients(43.3%).The factors that affected complete colonoscopy were also analyzed:Tumor location at an angle;stent placement at an angle;and stent expansion diameter,which affected complete colonoscopy significantly.However in multivariate analysis,stent expansion diameter was the only significant factor that affected complete colonoscopy.Complete evaluation using additional gastroscope was feasible in 42 patients(87.5%).CONCLUSION:Preoperative colonoscopy through the colonic stent using only conventional colonoscope was unfavorable.The narrow expansion diameter of the stent may predict unfavorable outcome.In such a case,using small caliber scope should be considered and may expect successful outcome.

Evaluation of non-ampullary duodenal polyps: Comparison of non-neoplastic and neoplastic lesions

AIM: To evaluate duodenal polyps, divided into nonneoplastic and neoplastic lesions. In addition, the clinical characteristics of duodenal hyperplastic polyps are determined. METHODS: We analyzed medical records of 50 114 consecutive patients submitted to for first diagnostic esophago-gastroduodenoscopy between January 2004 and December 2009. We excluded lesions on the ampulla of Vater and submucosal tumors. We studied 510 cases that were diagnosed endoscopically with duodenal polyps and enrolled a total of 221 cases that had undergone tissue biopsy. We analyzed the differences between non-neoplastic and neoplastic lesions, and determined the clinical features of duodenal hyperplastic polyps. RESULTS: Non-neoplastic lesions were found in 196 patients and neoplastic lesions in 25 patients. On uni-variate analysis, there were significant differences in shape, location, and size. Polyps more than 10 mm in diameter or polyps in the second portion had independent risk factors for being neoplastic lesions, as identified by multivariate analysis. In 23 cases of hyperplastic polyps (79.3%), they were accompanied by gastroduodenal pathology, which was possibly associated with Helicobacter pylori . CONCLUSION: Polyps of more than 10 mm or polyps in the second portion of the duodenum should be evaluated by histological examination.

Effects of Polymeric Stabilizers on the Synthesis of Gold Nanoparticles

Gold nanoparticles （AuNPs） stabilized with sodium alginate （SA）, glycol chitosan （GC）, polyvinyl alcohol （PVA）, and polyethyleneimine （PEI） were synthesized in aqueous solutions at room temperature. Different sizes and size distributions of AuNPs were obtained according to the polymeric stabilizers. The mean particle diameters of AuNPs synthesized with GC and PVA as stabilizers were about 5.1 and 5.3 nm, respectively, while those of AuNPs stabilized with SA and PEI were 8.4 and 10.8 nm, respectively. When SA was used, relatively large particles aggregated to form large clusters. In the case of GC, a number of small particles built up large clusters. When PVA was used, the size and the number of nanoperticles were estimated small with a low weight content of Au. For this reason, the PVA-stabilized AuNPs formed clusters with a small hydrodynamic size. The AuNPs synthesized in the aqueous solution of PEI without a reducing agent, sodium borohydride, were uniform in size and formed the smallest nanoclusters （67.4 nm）. In this case, the highest Au content was obtained. Sufficiently grown nanoparticles with a high Au content and a limited hydrodynamic size are considered to be suitable for a variety of applications.