| 1. |
- Linden, Sara K., et al.
(författare)
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Four modes of adhesion are used during Helicobacter pylori binding to human mucins in the oral and gastric niches
- 2008
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 13:2, s. 81-93
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Tidskriftsartikel (refereegranskat)abstract
- Background: Helicobacter pylori causes peptic ulcer disease and gastric cancer, and the oral cavity is likely to serve as a reservoir for this pathogen. We investigated the binding of H. pylori to the mucins covering the mucosal surfaces in the niches along the oral to gastric infection route and during gastric disease and modeled the outcome of these interactions. Materials and Methods: A panel of seven H. pylori strains with defined binding properties was used to identify binding to human mucins from saliva, gastric juice, cardia, corpus, and antrum of healthy stomachs and of stomachs affected by gastritis at pH 7.4 and 3.0 using a microtiter-based method. Results: H. pylori binding to mucins differed substantially with the anatomic site, mucin type, pH, gastritis status, and H. pylori strain all having effect on binding. Mucins from saliva and gastric juice displayed the most diverse binding patterns, involving four modes of H. pylori adhesion and the MUC5B, MUC7, and MUC5AC mucins as well as the salivary agglutinin. Binding occurred via the blood-group antigen-binding adhesin (BabA), the sialic acid-binding adhesin (SabA), a charge/low pH-dependent mechanism, and a novel saliva-binding adhesin. In the healthy gastric mucus layer only BabA and acid/charge affect binding to the mucins, whereas in gastritis, the BabA/Le(b)-dependent binding to MUC5AC remained, and SabA and low pH binding increased. Conclusions: The four H. pylori adhesion modes binding to mucins are likely to play different roles during colonization of the oral to gastric niches and during long-term infection.
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| 4. |
- Garcia-Amado, M. Alexandra, et al.
(författare)
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Non-pylori Helicobacteraceae in the upper digestive tract of asymptomatic venezuelan subjects: Detection of helicobacter cetorum-like and candidatus Wolinella africanus-like DNA
- 2007
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 12:5, s. 553-558
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Tidskriftsartikel (refereegranskat)abstract
- Background: The spectrum of human non-pylori Helicobacter infections is expanding, with species such as H. heilmannii and H. felis occasionally being associated with gastritis. However, the existence of non-pylori Helicobacter colonization in asymptomatic subjects has not been evaluated. The aim of this study was to investigate whether Helicobacter species other than pylori are present in the upper digestive tract of asymptomatic human subjects. Materials and methods: A Helicobacteraceae-specific semi-nested polymerase chain reaction (PCR) assay was used to detect Helicobacter-like organisms in the upper digestive tract of 91 Venezuelan volunteers (aged 18-68 years, 41 females, 50 males). Species were identified by denaturing gradient gel electrophoresis analysis and sequencing of the PCR products. Results: We detected DNA sharing 99-100% sequence identity in over 300-400 bp with the 16S rRNA genes of H. pylori, H. cetorum, and Candidatus Wolinella africanus in 76%, 16%, and 15% of the subjects, respectively. Multiple colonization was documented in 10% of the subjects: H. cetorum and Candidatus W. africanus (4%), H. pylori and Candidatus W. africanus (4%), and H. pylori and H. cetorum (2%). Conclusions: Our results suggest that non-pylori Helicobacteraceae colonization is relatively common in the Venezuelan asymptomatic population. This is the first report documenting the presence of H. cetorum DNA in the human upper digestive tract, and the second report of the recently discovered Candidatus W. africanus.
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| 6. |
- Hynes, Sean, et al.
(författare)
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Comparative chemical and biological characterization of the lipopolysaccharides of gastric and enterohepatic helicobacters
- 2004
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 9:4, s. 313-323
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Tidskriftsartikel (refereegranskat)abstract
- Background. The lipopolysaccharide of Helicobacter pylori plays an important role in colonization and pathogenicity. The present study sought to compare structural and biological features of lipopolysaccharides from gastric and enterohepatic Helicobacter spp. not previously characterized.Materials and methods. Purified lipopolysaccharides from four gastric Helicobacter spp. (H. pylori, Helicobacter felis, Helicobacter bizzozeronii and Helicobacter mustelae) and four enterohepatic Helicobacter spp. (Helicobacter hepaticus, Helicobacter bilis, Helicobacter sp. flexispira and Helicobacter pullorum) were structurally characterized using electrophoretic, serological and chemical methods.Results. Structural insights into all three moieties of the lipopolysaccharides, i.e. lipid A, core and O-polysaccharide chains, were gained. All species expressed lipopolysaccharides bearing an O-polysaccharide chain, but H. mustelae and H. hepaticus produced truncated semirough lipopolysaccharides. However, in contrast to lipopolysaccharides of H. pylori and H. mustelae, no blood group mimicry was detected in the other Helicobacter spp. examined. Intra-species, but not interspecies, fatty acid profiles of lipopolysaccharides were identical within the genus. Although shared lipopolysaccharide-core epitopes with H. pylori occurred, differing structural characteristics were noted in this lipopolysaccharide region of some Helicobacter spp. The lipopolysaccharides of the gastric helicobacters, H. bizzozeronii and H. mustelae, had relative Limulus amoebocyte lysate activities which clustered around that of H. pylori lipopolysaccharide, whereas H. bilis, Helicobacter sp. flexispira and H. hepaticus formed a cluster with approximately 100010,000-fold lower activities. H. pullorum lipopolysaccharide had the highest relative Limulus amoebocyte lysate activity of all the helicobacter lipopolysaccharides (10-fold higher than that of H. pylori lipopolysaccharide), and all the lipopolysaccharides of enterohepatic Helicobacter spp. were capable of inducing nuclear factor-Kappa B(NF-B) activation.Conclusions. The collective results demonstrate the structural heterogeneity and pathogenic potential of lipopolysaccharides of the Helicobacter genus as a group and these differences in lipopolysaccharides may be indicative of adaptation of the bacteria to different ecological niches.
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| 7. |
- Nilsson, Hans-Olof, et al.
(författare)
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Helicobacter pylori and Extragastric Diseases - Other Helicobacters.
- 2005
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 10 Suppl 1:s1, s. 54-65
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Forskningsöversikt (refereegranskat)abstract
- The involvement of Helicobacter pylori in the pathogenesis of extragastric diseases continues to be an interesting topic in the field of Helicobacter-related pathology. Although conflicting findings have been reported for most of the disorders, a role of H. pylori seems to be important especially for the development of cardiovascular and hematologic disorders. Previously isolated human and animal Helicobacter sp. flexispira and "Helicobacter heilmannii" strains have been validated using polyphasic taxonomy. A novel enterohepatic Helicobacter has been isolated from mastomys and mice, adding to the list of helicobacters that colonize the liver. Genetic targets that may aid the classification of novel Helicobacter species have emerged. Animal models of Helicobacter-induced gastric and hepatobiliary diseases have offered insights to the mechanisms associated with premalignant transformation.
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| 8. |
- Oona, M, et al.
(författare)
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Helicobacter pylori infection in children in Estonia: Decreasing seroprevalence during the 11-year period of profound socioeconomic changes
- 2004
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 9:3, s. 233-241
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Tidskriftsartikel (refereegranskat)abstract
- Background. The prevalence of Helicobacter pylori infection is inversely associated with socioeconomic conditions in childhood. In Estonia, a high prevalence of H. pylori infection has been observed among children born in 1987 and earlier. Since 1991, after the dissolution of the USSR, profound social and economic changes have taken place in the country. The aim of the study was to evaluate changes in the seroprevalence of H. pylori infection among children in the period 1991-2002. Materials and Methods. The hospital-based study population consisted of two groups of children enrolled in 1991 (n = 425) and 2002 (n = 296) according to the same inclusion criteria. The immunoglobulin G antibodies to the cell surface proteins of H. pylori were determined by enzyme-linked immunosorbent assay, and the sera with the borderline results were analyzed by immunoblot analysis. Multiple regression analysis was used to determine the associations between H. pylori seropositivity and different variables such as demographic characteristics, diagnoses and year of enrolment. Results. The only two variables linked independently to H. pylori serostatus were age and year of enrolment: the adjusted odds of being H. pylori seropositive were 1.92 [95% confidence interval (CI) 1.33-2.76] times higher for the children enrolled in 1991 compared with the children enrolled in 2002. The age-standardized seroprevalence rate was 42.2% (95% CI 37.4-47.0%) for the group of 1991 and 28.1% (95% CI 23.1-33.6%) for the group of 2002. Conclusion. The prevalence of H. pylori infection among children has significantly decreased during the 11-year period of profound socioeconomic changes in Estonia.
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| 9. |
- Simán, Henrik, et al.
(författare)
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Helicobacter pylori infection is associated with a decreased risk of developing oesophageal neoplasms
- 2001
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 6:4, s. 310-316
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Tidskriftsartikel (refereegranskat)abstract
- Background. The role of Helicobacter pylori infection in the development of oesophageal malignancies was investigated through a multivariate conditional logistic regression analysis in a nested case-control study. Methods. Blood samples and a questionnaire on smoking and alcohol habits were collected from a cohort of 32,906 city residents during a health-screening programme between 1974 and 1992. Forty-four cases of oesophageal cancer and 149 matched controls were selected. The mean interval between screening and cancer diagnosis was 11.9 years. H. pylori seropositivity was determined by an enzyme-linked immunosorbant assay measuring IgG. Occupation was included in the statistical analysis as an indicator of socio-economic status. Results. Helicobacter pylori seropositivity was present in 10 of the cases (22.7%) and 67 of the controls (45.0%). In a multivariate model, vith adjustment for occupation, tobacco and alcohol consumption, the odds ratio for developing in oesophageal malignancy when infected with H. pylori was 0.29 (95% confidence interval (CI): 0.12-0.67). Current smokers had an odds ratio of 17.3 (95% Cl: 3.0-99.4) and the odds ratio for ex-smokers was 5.9 (95% CI: 1.15-29.9). High alcohol consumption was no longer significantly, associated with oesophageal neoplasms after tobacco smoking was included into the model, odds ratio 1.22 (95% CI: 0.46-3.2). The protective effect of H. pylori was more pronounced for oesophageal adenocarcinoma (seven cases, odds ratio 0.16, 95% Cl: 0.00-1.06) than for squamous-cell carcinoma (29 cases, odds ratio 0.41, 95% Cl: 0.14-1.2). Conclusions. Helicobacter pylori infection is associated with a decreased risk of developing an oesophageal malignancy. Current smokers and ex-smokers have instead a definite increased risk of oesophageal neoplasms.
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| 10. |
- Tolia, Vasundhara, et al.
(författare)
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Detection of Helicobacter ganmani-Like 16S rDNA in Pediatric Liver Tissue
- 2004
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 9:5, s. 460-468
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Tidskriftsartikel (refereegranskat)abstract
- Background. To determine the presence of Helicobacter species in the liver biopsy specimens from children with various chronic liver diseases as data in adult literature suggests a possible role of these bacteria in their pathogenesis.Materials and methods. Paraffin sections of 61 liver biopsies of pediatric patients with miscellaneous diseases and autopsy liver tissue from 10 control subjects with no evidence of preexisting liver disease were examined for the presence of Helicobacter species by a genus-specific seminested polymerase chain reaction (PCR) assay. PCRproducts of positive samples were further characterized by denaturing gradient gel electrophoresis (DGGE) and DNA-sequence analysis. Based on those results, a seminested PCR assay for H. ganmani was developed and applied to the samples.Results. On analysis, 40/61 patient samples were positive in the genus-specific Helicobacter PCR and 4/10 from the control group. The nucleotide sequences of 16S rDNA fragments were 99100 similar to mainly Helicobacter sp. liver and H. ganmani. PCR-products similar to H. canis and H. bilis were also found. The 16S rDNAs of control specimens showed similarity to Helicobacter sp. liver. In the H. ganmani-specific PCR analysis 19 patients, but none of the controls, were positive.Conclusions. Amplified Helicobacter 16S rDNAs were related to Helicobacter sp. liver or H. ganmani in liver biopsy specimens of pediatric patients. The possible significance of Helicobacter species in pediatric liver diseases needs to be evaluated further in prospective studies.
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