| Helicobacter pylori (H.pylori)organisms are gram-negative bacteria infected the gastric mucosa of 20-80% of human population throughout the world. Most infected persons are asymptomatic ,only a few develop serious gastroduodenal diseases. It is a major caustive agent of duodenal ulcer and chronic gastritis, and it is possibly related with the devolopment of gastric cancinoma. Thus, it attracts a lot of investigators focusing on the further and wider study of H.pylori. However, many fields regarding the pathogenesis, transmission and management of the disease are not yet well-understood. For example, whether oral cavity is one of the colonizing enviroment of H.pylori;why there are great difference in clinical outcome after infection of H.pylori; how to distinguish between recrudescence from reinfection after H.pylori eradication. So we examined the usefulness of 16sRNA and vacA gene to simutaneously amplify H.pylori in saliva and gastric tissues, and compared its specificity and sensitivity with conventional detection approach of H.pylori ( the rapid urease test and Warthin-Starry test. Using the specific primers amplifying and differentiating the typeS1 and typeS2 signal sequences, it was predicted that 259-and 289-bp products would be PCR-amplified products from typeSi and typeS2 strains, respectively. Each strain only yield a PCR product of one of the two. The former size derived from the signal sequences of Tox+60190 expressing cytotoxin, named vacA1; the latter size oringinated from the signal sequences of Tox" Tx30a unexpressing cytotoxin, called vacA2. In addition, PCR-SSCP analysis were performed with PCR products of vacA, it was predicted to differeniate various H.pylori strains and explore specific subtypes of H.pylori strains for their association with clinical... |
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