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Yukinao Yamazaki

Publications and source records attributed to Yukinao Yamazaki.

8 recordsLinked to original sources
PubMed2004

Association between diversity in the Src homology 2 domain--containing tyrosine phosphatase binding site of Helicobacter pylori CagA protein and gastric atrophy and cancer.

We investigated the relationship between the diversity of Helicobacter pylori CagA protein and clinical outcome. The cagA gene was sequenced in 115 clinical isolates. The binding affinity of CagA to Src homology 2 domain-containing tyrosine phosphatase (SHP-2) was examined by in vitro infection. Two major CagA subtypes were observed--the East Asian and the Western type. The grades of inflammation, activity of gastritis, and atrophy were significantly higher in patients with gastritis infected with the East Asian CagA-positive strain than in patients with gastritis infected with cagA-negative or Western CagA-positive strains. All strains isolated from patients with gastric cancer were East Asian CagA positive. East Asian CagA exhibited stronger SHP-2-binding activity than did Western CagA. These findings suggest that infection with East Asian CagA-positive H. pylori is associated with atrophic gastritis and gastric cancer and that persistent active inflammation induced by the East Asian CagA-positive strain may play a role in the pathogenesis of disease.

Amino Acid Sequence↗
PubMed2004

Distinct diversity of the cag pathogenicity island among Helicobacter pylori strains in Japan.

The severity of Helicobacter pylori-related disease is correlated with the presence of a cag pathogenicity island (PAI). Genetic diversity within the cag PAI may have a modifying effect on the pathogenic potential of the infecting strain. We analyzed the complete cag PAI sequences of 11 representative Japanese strains according to their vacA genotypes and clinical effects and examined the relationship between the diversity of the cag PAI and clinical features. The cag PAI genes were divided into two major groups, a Western and a Japanese group, by phylogenetic analysis based on the entire cag PAI sequences. The predominant Japanese strains formed a Japanese cluster which was different from the cluster formed by Western strains. The diversity of the cag PAI was associated with the vacA and cagA genotypes. All strains with the s1c vacA genotype were in the Japanese cluster. In addition, all strains with the East Asian-type cagA genotype were also in the Japanese cluster. Patients infected with the Japanese-cluster strain had high-grade gastric mucosal atrophy. These results suggest that a distinct diversity of the cag PAI of H. pylori is present among Japanese strains and that this diversity may be involved in the development of atrophic gastritis and may increase the risk for gastric cancer.

Antigens, Bacterial↗
PubMed2003

Effects of percutaneous endoscopic gastrostomy tube placement on gastric antral motility and gastric emptying.

BACKGROUND: Percutaneous endoscopic gastrostomy (PEG) is the preferred method for providing enteral nutritional support in patients with dysphagia. We examined gastric antral myoelectrical activity and gastric emptying before and after PEG tube placement to evaluate the effects of PEG on gastric motility. METHODS: PEG was performed in 41 patients; 21 fed by total parenteral nutrition (TPN) and 20 who received nasogastric tube feeding (NGF). Antral myoelectrical activity and gastric emptying were examined before and 4 weeks after PEG tube placement. RESULTS: The percentage of normal-range electrogastrograms (EGGs) was significantly lower in the TPN group than in the NGF group in both the pre- and postprandial periods before PEG tube placement. Enteral feeding after PEG tube placement improved gastric motility in the patients with TPN. The percentage of normal-range EGGs increased significantly after PEG tube placement in both the pre- and postprandial periods, and plasma concentrations of paracetamol increased significantly after PEG tube placement in patients with TPN. A total of 7.3% of the patients developed the complication of gastroesophageal reflux (GER) after PEG tube placement. Gastric myoelectrical activity and gastric emptying were improved in these patients with GER after PEG tube placement. In contrast, the prevalence of esophageal hiatus hernia was significantly higher in patients with GER after PEG tube placement than in patients without GER after PEG tube placement. CONCLUSIONS: Prolonged TPN with bowel rest induces physiological dysfunction of gastric motility. Enteral nutrition is the preferable physiological nutritional route. GER after PEG tube placement is not related to gastric motility. Esophageal hiatus hernia seems to be a major risk factor for GER complications after PEG tube placement. Percutaneous endoscopic gastrostomy (PEG) is the preferred method for providing enteral nutritional support in patients with dysphagia. We examined gastric antral myoelectrical activity and gastric emptying before and after PEG tube placement to evaluate the effects of PEG on gastric motility.

Acetaminophen↗
PubMed2002

Correlation between variation of the 3' region of the cagA gene in Helicobacter pylori and disease outcome in Japan.

Genetic diversity within the cag pathogenicity island (PAI) of Helicobacter pylori may have a modifying effect on the pathogenic potential of the infecting strain. The genetic structure of the cag PAI was examined in Japanese isolates. The composition and nucleotide sequences of the cag PAI were quite similar among strains; however, diversity between 2 cag genes (virB10 and cagA) was observed. The variety in the number of repetition of the 5-amino acid sequence R1 (EPIYA) in the 3' region of the cagA gene was identified. The frequencies of the genotypes that contained >4 R1 sequences were significantly higher in atrophic gastritis-causing strains than in duodenal ulcer-causing strains. One-third of strains with >4 R1 sequences were gastric cancer-causing strains. Although the cag PAI is conserved in H. pylori isolates in Japan, H. pylori infection with the cagA genotype with >4 R1 sequences may correlate with the pathogenesis of atrophic gastritis and gastric cancer.

Amino Acid Sequence↗
PubMed2002

[Plaunotol].

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2-Pyridinylmethylsulfinylbenzimidazoles↗