| Research Abstract |
To examine association of Helicobacter pylori infection with the occurrence of gastroduodenal diseases, isolation of H.phlori from patients with the diseases was carried out. Isolation rates of H.pylori from the patients with gastric ulcer, duodenal ulcer and atrophic gastritis were 83,85 and 75%, respectively. In contrast, those from the patients with acute superficial gastritis and submucosal tumour were 25 and 33%, respectively. Sensitivity, specificity, positive^- and negative^-predictive values of rapid urease test of biopsy specimens to cultivation method were 76,85,91 and 63%, respectively, indicating that the rapid urease test is an useful screening test. By quantitative culture, it was shown that 5,000 - 10,000 CFU of H.phlori were required for positive reaction in the urease test.
Nearly half strains of H.phlori produce cytotoxin (CT) which induces vacuolation in cultured cells. It was demonstrated that CT was heat-labile at 70ﾟC and proteinous toxin with molecular weight of more than 20kDa. After precipitation of CT with 50% ammonium sulphate, purification of CT was tried using Sephacryl S300, phenylsuperose, Q Sepharose FF and Mono Q columns. However, highly purified CT was not obtained by these procedures. Positive rates for detection of CT using RK-13 (rabbit kidney), FL (human amnion), Vero (monkey kidney), BHK-21 (hamster kidney) and HeLa (human uterine cancer) cells were 73,61,27,27 and 21%, respectively, indicating that RK-13 cell line is a good indicator.
Adherence activity of H.phlori strains to human gastric cancer (MKN45, KATO III) cells and human intestine (Int-407) cells was analyzed by flowcytometer. Average adherence rates of H.pylori straius to MKN 45, KATO III and Int-407 cells were 76.6,42.7 and 15.1%, respectively. These results suggest that H.pylori has an affinity to gastric cells, particularly MKN 45 cells, rather than instinal cells. No significant correlation between adherence activity of and CT production by H.pylori was observed.
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