نتایج جستجو برای: vaca c

تعداد نتایج: 1057856  

2016
Charlotte G Sinnett Darren P Letley Geetha L Narayanan Sapna R Patel Nawfal R Hussein Abed M Zaitoun Karen Robinson John C Atherton

AIMS Helicobacter pylori infection is the major cause of peptic ulceration and gastric cancer, and an important virulence determinant is its vacuolating cytotoxin vacA. Previously, we have described allelic variation in vacA which determines toxin activity and disease risk. Here we aimed to quantify vacA mRNA expression in the human stomach, define its genetic determinants and assess how well i...

Journal: :Cancer research 2003
Timothy L Cover Uma S Krishna Dawn A Israel Richard M Peek

Chronic gastritis induced by Helicobacter pylori is a strong risk factor for the development of distal gastric adenocarcinoma. A specific host response to H. pylori that may contribute to gastric carcinogenesis is epithelial cell apoptosis. The aim of this study was to investigate the capacity of H. pylori vacuolating toxin (VacA) to induce gastric epithelial cell apoptosis. When cocultured wit...

2013
Kaneo Satoh Toshiya Hirayama Katsuhiro Takano Katsue Suzuki-Inoue Tadashi Sato Masato Ohta Junko Nakagomi Yukio Ozaki

Platelets were activated under the infection with H. pylori in human and mice. We investigated the role of VacA, an exotoxin released by H. pylori in this context. Acid-activated VacA, but not heated VacA, induced platelet CD62P expression. However, VacA reacted with none of the alleged VacA receptors present on platelet membranes. We therefore analyzed VacA associated proteins obtained through...

2017
Mark S. McClain Amber C. Beckett Timothy L. Cover

Helicobacter pylori VacA is a channel-forming toxin unrelated to other known bacterial toxins. Most H. pylori strains contain a vacA gene, but there is marked variation among strains in VacA toxin activity. This variation is attributable to strain-specific variations in VacA amino acid sequences, as well as variations in the levels of VacA transcription and secretion. In this review, we discuss...

Journal: :The Biochemical journal 2004
Nicholas A Geisse Timothy L Cover Robert M Henderson J Michael Edwardson

The Helicobacter pylori vacuolating toxin VacA causes several effects on mammalian cells in vitro, including intracellular vacuolation, formation of pores in the plasma membrane and apoptosis. When added to cells, VacA becomes associated with detergent-resistant membranes, indicating that it binds preferentially to lipid rafts. In the present study, we have used atomic force microscopy to exami...

Journal: :Turkish journal of medical sciences 2014
Ceren Erdoğdu Zeynep Saribaş Yakut Akyön Yilmaz

AIM The cagA and vacA profiles and their association with clinical findings show a distinct geographical distribution. In the present study, we aimed to determine the cagA status and vacA allelic subtypes in strains isolated from a university hospital in Ankara and to evaluate their associations with histopathological and endoscopic findings. MATERIALS AND METHODS A total of 120 H. pylori str...

2016
Ciara Utsch Rainer Haas

Vacuolating cytotoxin A (VacA) is a secreted pore-forming toxin and one of the major virulence factors of Helicobacter pylori (H. pylori), which actively supports the persistence and survival of the bacteria in the special ecological niche of the human stomach. H. pylori genomes harbor different allelic forms of the vacA gene, which translate into functionally distinct VacA toxin types. VacA in...

Journal: :Journal of clinical microbiology 2012
Rui M Ferreira Jose C Machado Darren Letley John C Atherton Maria L Pardo Carlos A Gonzalez Fatima Carneiro Ceu Figueiredo

The present report describes a novel method for genotyping the virulence-associated vacA intermediate (i) region of Helicobacter pylori in archive material. vacA i-region genotypes as determined by the novel method were completely concordant with those of sequence analysis and with those of functional vacuolation activity. The method was further validated directly in gastric biopsy specimens of...

Journal: :Infection and immunity 2008
Susan E Ivie Mark S McClain Victor J Torres Holly M Scott Algood D Borden Lacy Rong Yang Steven R Blanke Timothy L Cover

Helicobacter pylori VacA is a secreted pore-forming toxin that is comprised of two domains, designated p33 and p55. The p55 domain has an important role in the binding of VacA to eukaryotic cell surfaces. A total of 111 residues at the amino terminus of p55 (residues 312 to 422) are essential for the intracellular activity of VacA, which suggests that this region may constitute a subdomain with...

Journal: :Clinical and diagnostic laboratory immunology 1999
G I Perez-Perez R M Peek J C Atherton M J Blaser T L Cover

Several different families of vacuolating toxin (vacA) alleles are present in Helicobacter pylori, and they encode products with differing functional activities. H. pylori strains containing certain types of vacA alleles have been associated with an increased risk for peptic ulcer disease. In this study, we tested serum samples and gastric juice from 19 H. pylori-negative and 39 H. pylori-posit...

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