Objective:To explore the results of different methods for managing multivariate missing data. Methods: Case deletion, simple imputation and multiple imputation were compared when used for analyzing the clinical data of 925 liver cancer patients with medium multivariate missing data. Results: There were differences among the 3 methods. When ?=0.05, the risk factors influencing patients' survival time were clinical staging,history of hepatic cirrhosis, portal vein tumor thrombas, and levels of g-GT and WBC with multiple imputation, and were TNM staging, lipiodol dose, AST and ALP with case deletion. The 3 more factors of simple imputation were TNM staging, ALP and AFP compared with multiple imputation. Conclusion: Simple imputation is superior to case deletion in management of multivariate missing data but tends to make standard error smaller and P value lower. Multiple imputation is more reasonable and scientific than the other 2 methods.

Objective: To investigate the effect of the acid inhibitor-Lansoprazole on the distribution of Helicobacter pylori (H.pylori) in stomach. Methods: Biopsy specimens were taken from the duodenal ulcer patients who underwent gastroscopy before and after the treatment of Lansoprazole. The biopsy specimens were taken from the lesser curvature of the antrum and the greater curvature of the corpus respectively. H&E and Warthin-Starry staining were used for detecting the changing of active gastritis and the positive rate of H.pylori. Results: (1)The positive rates of H.pylori before treatment, 4 weeks after treatment and 3 months after treatment, in the lesser curvature of the antrum were 93.02%, 58.14%, and 86.05%, respectively. The positive rate and density of H.pylori 4 weeks after treatment were greatly decreased compared with those before treatment (P