Objective To compare the levels of four factors between gastric mucosa of Han and Tibetan patients with chronic gastritis residing in districts at the same altitude in Qinghai Province.Methods Levels of malonic aldehyde ( MDA) , superoxide dismutase (SOD) , nitric oxide ( NO) and xanthine oxidase (XOD) in gastric mucosa of Han and Tibetan patients with chronic gastritis resident in same altitude districts were examined, and a comparative study was performed.Results Levels of MDA and SOD were significantly higher in gastric mucosa of Han patients (2 2699 ± 1.58906 nmol/mgprot and 134.6313 ±48.35329 U/mgport, respectively) than those of the Tibetan (1.7095 ± 1.19474 nmol/mgprot and 109.5056 ± 28.26794 U/mgport, respectively) (P <0.05) , which indicated there were differences in metabolism of oxygen free radicals and antioxi-dant free radicals between 2 ethnics.However, there were no differences in NO and XOD levels between two ethnical groups, which suggested no ethnical difference in metabolism of the two factors.Conclusion There is ethnical difference in MDA and SOD metabolism in gastric mucosa of Han and Tibetan patients with chronic gastritis from same altitude district, which is presumably due to the different tolerance to the hypoxia at high altitude.

Objective To evaluate the detection of serum pepsinogen (PG) in screening of gastric cancer. Methods (1) To calculate the detection rate of gastric cancer in PG Positive patients from northeastern, noah-western and northern China. (2) To determine the PG positive rate in patients with chronic superficial and atrophic gastritis. (3) To calculate the detection rate of gastric cancer, H. pylori infection and esophageal cancer in PG positive patients from gastric cancer high risk areas. Results (1) The detection rate of gastric cancer in PC, positive patients from Changchun (northeastern China), Xihing (northwestern China) and Beijing ( northern China) was 22. 58%, 25. 2% and 0, respectively. The sensitivity of PG to seeen gastric cancer in Changchun and Xihing was 50. 9% and 35.6%, and the specificity was 82. 56% and 85.69%, respectively. (2) Only 25% of patients with chronic atrophic gastritis were PG positive. (3) The serum PG level was measured in 2346 cases from gastric cancer high risk areas, and PG positive rate was 27.02% (634/2346), in which 496 patients (76. 65%, 496/634) received endoscopy, and gastric cancer was detected in 10 (2. 02%, 10/496), including 9 cases of early gastric caner. The prevalence of gastric cancer was 0. 43% in common population and 1.58% in PG positive population. The infection rate of H. pylori was 70. 73% in 2346 subjects and 2 cases of esophageal cancer, including 1 case of early cancer was diagnosed. Conclusion Serum PG level cannot be used as a marker for gastric cancer or atrophic gastritis, while it may be of value for gastric cancer screening in high risk areas.