6Tsuda M, Karita M, Morshed MG, et al. A urease-negative mutant of helicobacter pylori constructed by allelic exchage mutagenesis lacks the ability to colonize the nude mouse stomach[ J ]. Infect Immun, 1994,62: 3586.
7El-Zimaity HM, Graham DY. Evaluation of gastric mucosal biospy site and number for identification of helicobacter pylori or intestinal metaplasia: role of the Sydney System[J]. Hum Pathol, 1999,30:72.
8Rektoschek M, Weeks D, Sachs G, et al. Influence of pH on metabolism and urease activity of helicobacter pylori [ J ]. Crastroenterology, 1998,115: 628.
9Marshall B J, Warren JR, Francis GJ, et al. Rapid urease test in the management of campylobacter pylori-associated gastritis [ J ]. Am J Gastroenterol,1987,82:200.