Oxidative stress and nitric oxide in rats with alcohol-induced acute pancreatitis

AIM: Oxygen free radical mediated tissue damage is well established in pathogenesis of acute pancreatitis (AP).Whether nitric oxide (NO) plays a deleterious or a protective role is unknown. In alcohol-induced AP, we studied NO, lipooxidative damage and glutathione in pancreas, lung and circulation.METHODS: AP was induced in rats (n = 25) by injection of ethyl alcohol into the common biliary duct. A sham laparatomy was performed in controls (n = 15). After 24 h the animals were killed, blood and tissue sampling were done.RESULTS: Histopathologic evidence confirmed the development of AP. Marked changes were observed in the pulmonary tissue. Compared with controls, the AP group displayed higher values for NO metabolites in pancreas and lungs, and thiobarbituric acid reactive substances in circulation. Glutathione was lower in pancreas and in circulation. Glutathione and NO were positively correlated in pancreas and lungs of controls but negatively correlated in circulation of experimental group. In the experimental group, plasma thiobarbituric acid reactive substances were negatively correlated with pancreas thiobarbituric acid reactive substances but positively correlated with pancreas NO.CONCLUSION: NO increases in both pancreas and lungs in AP and NO contributes to the pathogenesis of AP under oxidative stress.

Colorectal stenting for palliation and as a bridge to surgery:A 5-year follow-up study

AIM: To evaluate the long-term effectiveness of colonic stents in colorectal tumors causing large bowel obstruction.METHODS: We retrospectively analyzed data from 49 patients with colorectal cancer who had undergone colorectal stent placement between January 2008 and January 2013. Patients' symptoms,characteristics and clinicopathological data were obtained by reviewing medical records. The obstruction was diagnosed clinically and radiologically. Histopathological diagnosis was achieved endoscopically. Technical success rate(TSR)was defined as the ratio of patients with correctly placed SEMS upon stent deployment across the entire stricture length to total number of patients. Clinical success rate(CSR) was defined as the ratio of patients with technical success and successful maintenance of stent function before elective surgery(regardless of number of SEMS deployed) to total number of patients. The surgical success rate(SSR) of colorectal stent as a bridge to surgery was defined as the ratio of patients with successful surgical procedures. Unsuccessful surgical outcomes were defined as being due to insufficient colonic decompression. The technical,clinical,surgical success rates and complications after stenting were assessed.RESULTS: The median age of patients was 64(36 to 89). 44.9% of patients were male and 55.1% were female. Eighteen patients had the obstruction located in the rectum,15 patients in the rectosigmoid region,10 patients in the sigmoid region,and 6 patients had a tumor causing obstruction in the proximal colon. Each patient was categorized pathologically as stage 2(32.7%,16 patients) or stage 3(42.9%,21 patients) and 12 patients(24.4%) had metastatic disease. None of the patients received chemotherapy before stenting. Stenting was undertaken in 37 patients as a bridge to surgery,and in 12 patients stents were used for palliation. Median time to surgery after stenting was 30 ± 91.9 d. All surgery was completed in one single operation and thus no colostomy with stoma was needed. The median overall survival rate of patients with stage 2-3 colorectal cancer was 53.1 mo and stage 4 was 37.1 mo(P = 0.04). Metastatic colorectal patients who were treated palliatively with stents had backbone chemotherapy with oxaliplatin and/or irinotecan-based regimens plus antiangiogenic therapies,especially bevacizumab. Resolution of the obstruction and clinical improvement was achieved in all patients. The technical,clinical and surgical success rates were 95.9%,100% and 94.6%,respectively.CONCLUSION: The efficacy and safety of colonic stents was demonstrated both as a bridge to surgery and for palliative decompression. In addition,results emphasize the importance of the skills of the endoscopist in colonic stenting.