Fragmentation of CagA Reduces Hummingbird Phenotype Induction by Helicobactor pylori.

Infection with Helicobacter pylori (H. pylori) has been linked to various gastro-intestinal diseases; nevertheless it remains to be clarified why only a minority of infected individuals develop illness. Studies from the West have indicated that the cagA gene and the associated EPIYA genotype of H. pylori is closely linked to the development of severe gastritis and gastric carcinoma; however, as yet no consistent correlation has been found among the bacteria from East Asia. In addition to genotype variation, the CagA protein undergoes fragmentation; however, the functional significance of fragmentation with respect to H. pylori infection remains unknown. In this study, we isolated 594 H. pylori colonies from 99 patients and examined the fragmentation patterns of CagA protein using immunoblotting. By analyzing the ability of the isolates to induce the host cell morphological transition to the highly invasive hummingbird phenotype, we demonstrated that H. pylori colonies with substantial CagA fragmentation are less potent in terms of causing this morphological transition. Our results uncovered a functional role for CagA fragmentation with respect to H. pylori-induced hummingbird phenotype formation and these findings suggest the possibility that the post-translational processing of CagA may be involved in H. pylori infection pathogenesis.

Mutagenicity study of butachlor and its metabolites using Salmonella typhimurium.

Butachlor is the most commonly used herbicide in Taiwan and many other countries. It has been reported to be an indirect mutagen and carcinogen in various in vitro assay systems. Previous investigation has also demonstrated that butachlor stimulates cell proliferation, transforms normal embryonic cells, and induces stomach tumors in Spraque-Dawley rats. However, the mechanism of butachlor carcinogenicity is still not clear. In order to clarify the toxicologic and carcinogenic properties of butachlor, we proposed a metabolic pathway, and synthesized the authentic metabolites by chemical methods. In addition, we tested the mutagenicity of butachlor and these metabolites on Salmonella typhimurium. The results indicate that butachlor might manifest its carcinogenicity via the mutagenicity of its metabolic products. Although the molecular mechanism of butachlor-induced cellular toxicity is still not clear, it is likely that the cellular transformation ability of butachlor is partly associated with its mutagenicity.

Aberrant expressions of annexin A10 short isoform, osteopontin and alpha-fetoprotein at chromosome 4q cooperatively contribute to progression and poor prognosis of hepatocellular carcinoma.

Chromosome 4q exhibits high frequency of allelic loss in hepatocellular carcinoma (HCC). This study aimed to elucidate the interaction of the frequent aberrant mRNA expression of alpha-fetoprotein (AFP), osteopontin (OPN) and a novel short isoform of annexin A10 (ANXA10S) at 4q in the tumor progression among 294 patients who received surgical resection of unifocal primary HCC. AFP overexpression, OPN overexpression and ANXA10S down-regulation correlated with high-grade and high-stage tumors, early tumor recurrence (all P<0.0001), and lower 10-year survival (all P=0.000001). The AFP overexpression correlated with OPN overexpression (P=0.0026) and ANXA10S down-regulation (P=0.00001), while OPN overexpression correlated with ANXA10S down-regulation (P=0.00001). Pair-wise combinations revealed interactive effects between these genetic variants for tumor grade, tumor stage and early recurrence (all P<0.0001). HCCs with more genetic aberrations had more frequent high tumor grade, portal vein invasion (stage IIIB-IV) and early recurrence (all P<0.0001). The 10-year survival rate for HCCs with all three genetic alterations was the lowest (7%), followed by those with two (22%) or one event (29%), and the highest for those without these changes (43%), P=0.000001. The prognostic stratification using these molecular factors was similar to that of histopathological staging. These three genetic alterations also helped to identify different subgroups of patients of stage II HCC but with different prognosis (P=0.015). In conclusion, the aberrant expressions of AFP, OPN and ANXA10S cooperatively contribute to tumor progression and poor prognosis, and are useful for molecular staging of HCC and the subclassification of stage II HCC without vascular invasion.

Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers.

AIM: Helicobacter pylori (H pylori) has been linked to chronic gastritis, peptic ulcers, gastric cancer and MALT-lymphoma. Conventional invasive tests are less sensitive than non-invasive tests in diagnosing H pylori infection in patients with bleeding peptic ulcers. Polymerase chain reaction is a sensitive and accurate method for diagnosing H pylori infection. The aim of this study was to evaluate the diagnostic role of mucosal polymerase chain reaction for H pylori infection in patients with bleeding peptic ulcers. METHODS: In patients with bleeding, non-bleeding peptic ulcers and chronic gastritis, we checked rapid urease test, histology, bacterial culture and mucosal polymerase chain reaction for detecting H pylori infection. Positive H pylori infection was defined as positive culture or both a positive histology and a positive rapid urease test. For mucosal polymerase chain reaction of H pylori, we checked vacA (s1a, s1b, s1c, s2, m1, m1T, m2), iceA1, iceA2 and cag A. RESULTS: Between October 2000 and April 2002, 88 patients with bleeding peptic ulcers (males/females: 60/28, gastric ulcers/duodenal ulcers: 55/33), 81 patients with non-bleeding peptic ulcers (males/females: 54/27, gastric ulcers/duodenal ulcers: 45/36) and 37 patients with chronic gastritis (males/females: 24/13) were enrolled in this study. In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, 45 patients (51%), 71 patients (88%) and 20 patients (54%) respectively were found to have positive H pylori infection (P<0.001). In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, polymerase chain reaction for H pylori infection was positive in 54 patients (61%), 70 patients (86%) and 20 patients (54%) respectively (P<0.001). The sensitivity, positive predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori infection were significantly lower in patients with bleeding peptic ulcers (84%, 79% and 81%) than in patients with non-bleeding peptic ulcers (99%, 99% and 98%) (P<0.001, P<0.01 and P<0.001 respectively). The sensitivity, negative predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori were significantly lower in patients with bleeding peptic ulcers (84%, 83% and 81%) than in patients with chronic gastritis (100%, 100% and 100%) (P = 0.02, P = 0.02 and P = 0.001). CONCLUSION: Mucosal polymerase chain reaction for detecting H pylori infection is not reliable in patients with bleeding peptic ulcers.

Helicobacter pylori stool antigen test in patients with bleeding peptic ulcers.

BACKGROUND: Helicobacter pylori has been linked to chronic gastritis, peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Invasive tests are less sensitive than noninvasive tests in diagnosing H. pylori infection in patients with bleeding peptic ulcers. The H. pylori stool antigen test has been useful in diagnosing H. pylori in patients with peptic ulcers before and after eradication of H. pylori. The aim of this study was to evaluate the H. pylori stool antigen test in patients with bleeding peptic ulcers. METHODS: Patients with bleeding and nonbleeding peptic ulcers underwent a rapid urease test, histology, bacterial culture and H. pylori stool antigen test. Positive H. pylori infection was defined as a positive culture or both a positive histology and a positive rapid urease test. Helicobacter pylori stool antigen was assessed with a commercial kit (Diagnostec H. pylori antigen EIA Kit, Hong Kong). RESULTS: Between October 2000 and April 2002, 93 patients with bleeding peptic ulcers (men/women: 78/15, gastric ulcer/duodenal ulcer: 58/35) and 59 patients with nonbleeding peptic ulcers (men/women: 47/12, gastric ulcer/duodenal ulcer: 30/29) were enrolled in this study. Forty-seven (50.5%) patients with bleeding peptic ulcers and 30 (50.8%) patients with nonbleeding peptic ulcers, were found to be infected with H. pylori (p > .1). Helicobacter pylori stool antigen tests were positive in 54 (58.1%) and 30 (50.8%) patients with bleeding peptic ulcers and nonbleeding peptic ulcers, respectively (p > .1). The sensitivity (82% vs. 93%), specificity (68% vs. 93%), positive predictive value (74% vs. 93%), negative predictive value (77% vs. 93%) and diagnostic accuracy (75% vs. 93%) were all lower in patients with bleeding vs. nonbleeding peptic ulcers. The specificity, positive predictive value, and diagnostic accuracy of the H. pylori stool antigen test in patients with bleeding peptic ulcers were significantly lower than those in patients with nonbleeding peptic ulcers (p = .01, p = .02 and p = .003, respectively). CONCLUSION: The H. pylori stool antigen test is not reliable for diagnosing H. pylori infection in patients with bleeding peptic ulcers.

Helicobacter pylori cagA, iceA and vacA genotypes in patients with gastric cancer in Taiwan.

AIM: Helicobacter pylori (H pylori ) has been linked to chronic gastritis, peptic ulcer, gastric cancer and MALT-lymphoma. The link of genotypes of H pylori to gastric cancer remains controversial. The aim of this study was to investigate the H pylori vacA alleles, cagA and iceA in patients with gastric cancer in Taiwan. METHODS: Patients with gastric cancer, peptic ulcer and chronic gastritis were enrolled in this study. We obtained biopsy specimens from the stomach at least 2 cm away from the tumor margin in patients with gastric cancer, and from the antrum of stomach in patients with peptic ulcer or chronic gastritis. DNA extraction and polymerase chain reaction were used to detect the presence or absence of cagA and to assess the polymorphism of vacA and iceA. RESULTS: A total of 168 patients (gastric ulcer: 77, duodenal ulcer: 66, and chronic gastritis: 25) were found to have positive PCR results of the biopsy specimens from patients with peptic ulcer and chronic gastritis. We found positive cagA (139/168, 83%), m2 (84/168, 50%) and iceA1 (125/168, 74%) strains in the majority of patients. In patients with gastric cancer, the vacA s1a and s1c subtypes were less commonly found than those in non-cancer patients (35/66 vs 127/168, P = 0.0001 for s1a and 13/66 vs 93/168, P<0.0001 for s1c). In the middle region, the m1T strain in patients with gastric cancer was more than that of non-cancer patients (23/66 vs 33/168, P = 0.02). CONCLUSION: In Taiwan, H pylori with positive vacA s1a, cagA and iceA1 strains are found in the majority of patients with gastric cancer or non-cancer patients. In patients with gastric cancer, the vacA s1a and s1c subtypes are less and m1T is more than in patients with peptic ulcer and chronic gastritis.

Genotypes of Helicobacter pylori in patients with peptic ulcer bleeding.

AIM: Helicobacter pylori causes chronic gastritis, peptic ulcer, gastric cancer and MALT-lymphoma. Different genotypes of Helicobacter pylori are confirmed from diverse geographic areas. Its association with bleeding peptic ulcer remains controversial. The aim of this study was to investigate the Helicobacter pylori vacA alleles, cagA and iceA in patients with bleeding peptic ulcer. METHODS: We enrolled patients with bleeding, non-bleeding peptic ulcers and chronic gastritis. Biopsy specimens were obtained from the antrum of the stomach for rapid urease test, bacterial culture and PCR assay. DNA extraction and polymerase chain reaction were used to detect the presence or absence of cagA and to assess the polymorphism of vacA and iceA. RESULTS: A total of 168 patients (60.4%) (25 patients with chronic gastritis, 26 patients with bleeding gastric ulcer, 51 patients with non-bleeding gastric ulcer, 26 patients with bleeding duodenal ulcer, and 40 patients with non-bleeding duodenal ulcer) were found to have positive PCR results between January 2001 and December 2002. Concerning genotypes, we found cagA (139/278, 50%), vacA s1a (127/278, 45.7%), and ice A1 (125/278, 45%) predominated in all studied patients. In patients with bleeding peptic ulcers, vacA s1a and m1T were fewer than those in patients with non-bleeding peptic ulcers (37/106 vs 69/135, P=0.017, and 4/106 vs 21/135, P =0.002). CONCLUSION: In patients with peptic ulcers, H pylori vacA s1a and m1T prevent bleeding complication.

Overexpression of osteopontin is associated with intrahepatic metastasis, early recurrence, and poorer prognosis of surgically resected hepatocellular carcinoma.

BACKGROUND: Intrahepatic metastasis via portal vein spread is an important feature and a crucial unfavorable prognostic factor of hepatocellular carcinoma (HCC). To identify the molecular factors for tumor progression, the authors used differential display (DD) to analyze aberrant gene expression in HCC. The goal of the current study was to elucidate the clinicopathologic and prognostic significance of osteopontin (OPN) in HCC progression. METHODS: OPN mRNA levels, which were increased preferentially in HCC in a DD assay and verified with Northern blotting, were measured in 240 surgically removed, unifocal, primary HCCs using the reverse transcription-polymerase chain reaction at the exponential phase. OPN mRNA expression was correlated with clinicopathologic features, particularly portal vein invasion, early tumor recurrence, and prognosis. RESULTS: Osteopontin mRNA was overexpressed in 133 tumors (55%). The OPN overexpression was associated closely with alpha-fetoprotein elevation (P = 0.001), p53 mutation (P = 0.021), larger tumors (P = 0.002), high-grade HCC (P < 0.001), late-stage HCC (P < 0.001), early tumor recurrence and/or metastasis (P = 0.003), and a lower 10-year survival rate (P = 0.00013). Multivariate analysis revealed that tumor stage and early tumor recurrence were crucial prognostic factors. In early-stage HCC, which has no vascular invasion and a lower early tumor recurrence than late-stage HCC, OPN mRNA overexpression predicted a higher early recurrence rate (P = 0.003). CONCLUSIONS: OPN mRNA overexpression was correlated closely with high-grade, late-stage, and early tumor recurrence, which lead to poorer prognosis. Osteopontin overexpression might serve as an unfavorable prognostic factor and a useful marker for predicting early recurrence in early-stage HCC.