Chemiluminescence assay of mucosal reactive oxygen species in gastric cancer, ulcer and antral mucosa.

BACKGROUND/AIMS: Reactive oxygen species (ROS) have been implicated in inflammatory and cancerous illness, including that of the gastrointestinal tract. The oxidative damage incurred during human gastric ulcer or cancer mucosa may be related to acumination of ROS. In this study, we aimed to demonstrate oxidative stress of gastric ulcer and cancer mucosa compared to gastric antral mucosa. PATIENTS: Thirty-four patients with gastric ulcer and gastric cancer were enrolled in this study. Gastric mucosa specimens, taken from upper GI endoscopic biopsy, from the lesion (ulcer or cancer) and antrum were sent for the activity of O2- or H2O2 determined by chemiluminescence assay. Protein concentrations in the tissue homogenates were determined by Bio-Red protein assay. The production of O2- or H2O2 per unit of protein was calculated by dividing the tissue CL level by the protein content of a tissue. RESULTS: The oxidative stress metabolites O2- and H2O2 of mucosa were evaluated by chemiluminescence assay in gastric lesions (27 ulcers and 7 cancers) and gastric antrum. Gastric lesion showed significantly increased O2- than antral mucosa (18.77 +/- 45.18 (counts/sec x microg), 95% CI 3.01, 34.53 vs. 3.58 +/- 6.89 (counts/sec x microg), 95% CI 1.18, 5.98, p < 0.05). There was also significantly greater expression of H2O2 in gastric lesion than gastric antral mucosa (76.06 +/- 148.36 (counts/sec x microg), 95% CI 24.30, 127.83 vs. 912.41 +/- 20.22 (counts/sec x microg), 95% CI 5.35, 19.46, p = 0.008). Differences of mucosal O2- and H2O2 between gastric ulcer and cancer were not significant. There was significant correlation of O2- and H2O2 generation in gastric lesion mucosa. CONCLUSIONS: Oxidative stress is now thought to make a significant contribution to inflammatory disease and malignancy. The reason that overproduction of free radicals is a feature of such a broad spectrum of diseases derived from the fact that oxidative metabolism is a necessary part of every cell's metabolism. In this study, we demonstrated increased ROS production in gastric ulceration and cancer compared with gastric antral mucosa.

Factors associated with failure of initial endoscopic hemoclip hemostasis for upper gastrointestinal bleeding.

BACKGROUND: Endoscopic hemoclip is widely used for the management of bleeding peptic ulcers. The major difficulty in clinical application of the hemoclip is deployment to the lesion during initial hemostasis. The aim of this study was to define factors associated with the failure of endoscopic hemoclip for initial hemostasis of upper GI bleeding. PATIENTS AND METHODS: From January to December 2003, we prospectively studied 77 randomized patients with clinical evidence of upper GI bleeding due to either active bleeding or a visible vessel identified by upper GI endoscopy in our emergency department. RESULTS: Among the 77 patients, 13 (16.9%) failed treatment (Group 1) and 64 (83.1%) were successfully (Group 2) treated by endoscopic hemoclip for lesions related to upper GI bleeding. There were no differences due to gender, blood pressure, initial heart rate, and hemoglobulin before or after endoscopic treatment, platelet count, serum creatinine, and albumin between groups. The mean age of Group 1 was higher than that of Group 2 (73.31+/-9.38 years vs. 65.41+/-16.45 years, respectively; P=0.083). Most patients who did not achieve initial hemostasis by endoscopic hemoclip had upper GI lesions over the gastric antrum and duodenal bulb. Among the 13 patients who failed to achieve endoscopic hemoclip initial hemostasis, four lesions were located over the posterior wall of the antrum, and four lesions over the lesser curvature side of the duodenal bulb. CONCLUSION: Endoscopic hemoclip is an effective hemostatic method for upper GI bleeding. Age, gastric antrum, and duodenal bulb lesions may be associated with the failure of initial hemostasis by endoscopic hemoclip.