The genotypes of 78 strains of Helicobacter pylori from Calcutta, India (55 from ulcer patients and 23 from more-benign infections), were studied, with a focus on putative virulence genes and neutral DNA markers that were likely to be phylogenetically informative. PCR tests indicated that 80 to 90% of Calcutta strains carried the cag pathogenicity island (PAI) and potentially toxigenic vacAs1 a...

Helicobacter pylori is one of the most diverse bacterial species that chronically infects more than 70% of Indian population. Interestingly, data showing microdiversity of the H. pylori strains within a particular gastric niche remained scarce. To understand the extent of genetic diversity among H. pylori strains within a given host, 30 patients with gastro-duodenal problems were subjected to e...

AIM Helicobacter pylori (H pylori) is associated with increased gastric inflammatory and epithelial expression of macrophage migration inhibitory factor (MIF) and gastric epithelial cell proliferation. This study aimed at determining whether H pylori directly stimulates release of MIF in monocytes, whether the cag pathogenicity island (PAI) is involved for this function, and whether MIF stimula...

Helicobacter pylori infection is associated with altered gastric epithelial cell turnover. To evaluate the role of oxidative stress in cell death, gastric epithelial cells were exposed to various strains of H. pylori, inflammatory cytokines, and hydrogen peroxide in the absence or presence of antioxidant agents. Increased intracellular reactive oxygen species (ROS) were detected using a redox-s...

The duodenal ulcer promoting (dupA) gene, located in the plasticity region of Helicobacter pylori, is associated with duodenal ulcer development. dupA was predicted to form a type IV secretory system (T4SS) with vir genes around dupA (dupA cluster). We investigated the prevalence of dupA and dupA clusters and clarified associations between the dupA cluster status and clinical outcomes in the U....

Acute Helicobacter pylori infection of gastric epithelial cells and human gastric biopsies represses H,K-ATPase α subunit (HKα) gene expression and inhibits acid secretion, causing transient hypochlorhydria and supporting gastric H. pylori colonization. Infection by H. pylori strains deficient in the cag pathogenicity island (cag PAI) genes cagL, cagE, or cagM, which do not transfer CagA into h...

To extend our knowledge of host-cell targets of Helicobacter pylori, we characterized the interaction between H. pylori and human T84 epithelial cell polarized monolayers. Transcriptional analysis by use of human microarrays and a panel of isogenic H. pylori mutants revealed distinct responses to infection. Of the 670 genes whose expression changed, most (92%) required the cag pathogenicity isl...

background: helicobacter pylori strains have two classical virulence genes, the cytotoxinassociated a ( caga ) gene and the vacuolating cytotoxin a ( vaca ) gene, which are located in the cag pathogenicity island ( cag pai). serum immunoglobulin g (igg) antibodies to h. pylori , especially, the caga antigen may be a reliable marker for selection of dyspeptic patients for upper endoscopy. method...

Infection with Helicobacter pylori (H. pylori) increases stomach cancer risk. Helicobacter pylori strains with the cag pathogenicity island (PAI) induce more severe inflammation in the gastric epithelium and are more strongly associated with stomach cancer risk than strains lacking the PAI. We examined whether the prevalence of somatic p53 mutation in gastric adenocarcinoma differed between sub...