The Genetic Diversity of Helicobacter pylori Virulence Genes Is Not Associated with Gastric Atrophy Progression

Atrophy of the gastric mucosa is a precursor of intestinal-type gastric cancer, and Helicobacter pylori infection causes atrophic gastritis. The aim of this study was to determine whether the genetic diversity of H. pylori virulence genes is associated with the development and progression of gastric atrophy in humans. We isolated and cultured H. pylori strains from patients with gastric ulcer and duodenal ulcer accompanied by atrophic gastritis in background mucosa. H. pylori strains were stored at －80℃ prior to the experiments being carried out. We analyzed iceA, babA, vacA, cagA, and cagE genes by PCR. The cagA gene was analyzed through sequencing of the C-terminal region containing the EPIYA motif, which is related to tyrosine phosphorylation. Severe atrophy was observed in patients with gastric ulcer. The major phenotype of the vacA gene was s1c/m1 (93ｵ). The cagA gene was detected in all strains. The cagE gene was not detected in 2 and 5 strains from the mild cases and severe cases, respectively. The major cagA EPIYA motif, which is amino acids repeat in the C terminus, was the A-B-D type (44 of 58 strains). The virulence genes were not statistically associated with the severity of atrophy in the background gastric mucosa in humans. Not only identification of bacterial virulence factors but also studies of the host response will be necessary to investigate the progression of gastric atrophy and subsequent cancer development in humans

Establishment and Evaluation of a New Chemiluminescent Enzyme Immunoassay for Carcinoembryonic Antigen Adapted to the Fully Automated ACCESS® System

Peer Reviewe

Synthesis and Characterization of Comb-Shaped Ring Polystyrenes

A series of comb-shaped ring polystyrene samples, RC, composed of a common ring backbone and multiple linear branches with three different lengths were successfully prepared. First, a highly purified ring backbone was synthesized by anionic polymerizations followed by multistep size exclusion chromatography (SEC) and interaction chromatography (IC) fractionations. Second, this backbone was reacted with an excess molar amount of anionic living linear branch chains. Through the coupling reactions, the targeted RC samples were successfully obtained with high grafting efficiency without causing any side reactions. Their chain dimensions in THF were investigated by SEC-MALS measurements, and they were evaluated by estimating the shrinking factor <i>g</i>^1/2 (= <i>R</i>_g,comb/<i>R</i>_g,linear). All RC samples prepared in this study exhibited smaller <i>R</i>_g and <i>g</i>^1/2 values than those of the corresponding linear combs, LC. Moreover, combs with short branches exhibited an evidently larger <i>g</i>^1/2 than the Gaussian chains due to the intramolecular excluded volume effects, being originated from the local high segment density in the vicinity of the branch points. In contrast, <i>g</i>^1/2 for combs having long branches agreed reasonably well with the values based on the Gaussian approximation. This result suggests that the intramolecular excluded volume effect is weakened with increasing branch chain length, and consequently the comb behaves like a star polymer. Thus, characteristic chain dimensions of comb-shaped ring samples have been clarified, which strongly depend on the branch chain length and the backbone architecture