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1.
BMC Microbiol ; 11: 61, 2011 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-21435255

RESUMEN

BACKGROUND: Helicobacter pylori infection is one of the most common infections worldwide and is associated with gastric cancer and peptic ulcer. Bacterial virulence factors such as CagA have been shown to increase the risk of both diseases. Studies have suggested a causal role for CagA EPIYA polymorphisms in gastric carcinogenesis, and it has been shown to be geographically diverse. We studied associations between H. pylori CagA EPIYA patterns and gastric cancer and duodenal ulcer, in an ethnically admixed Western population from Brazil. CagA EPIYA was determined by PCR and confirmed by sequencing. A total of 436 patients were included, being 188 with gastric cancer, 112 with duodenal ulcer and 136 with gastritis. RESULTS: The number of EPIYA C segments was significantly associated with the increased risk of gastric carcinoma (OR=3.08, 95% CI=1.74 to 5.45, p<10-3) even after adjustment for age and gender. Higher number of EPIYA C segments was also associated with gastric atrophy (p=0.04) and intestinal metaplasia (p=0.007). Furthermore, patients infected by cagA strains possessing more than one EPIYA C segment showed decreased serum levels of pepsinogen I in comparison with those infected by strains containing one or less EPIYA C repeat. Otherwise, the number of EPIYA C segments did not associate with duodenal ulcer. CONCLUSIONS: Our results demonstrate that infection with H. pylori strains harbouring more than one CagA EPIYA C motif was clearly associated with gastric cancer, but not with duodenal ulcer.Higher number of EPIYA C segments was also associated with gastric precancerous lesions as demonstrated by histological gastric atrophic and metaplastic changes and decreased serum levels of pepsinogen I.


Asunto(s)
Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Úlcera Duodenal/epidemiología , Infecciones por Helicobacter/complicaciones , Helicobacter pylori/genética , Helicobacter pylori/patogenicidad , Neoplasias Gástricas/epidemiología , Adulto , Anciano , Antígenos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Brasil/epidemiología , ADN Bacteriano/química , ADN Bacteriano/genética , Úlcera Duodenal/microbiología , Infecciones por Helicobacter/microbiología , Humanos , Persona de Mediana Edad , Fosforilación , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Análisis de Secuencia de ADN , Neoplasias Gástricas/microbiología
2.
Int J Med Microbiol ; 301(3): 225-8, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21050811

RESUMEN

The dupA of Helicobacter pylori has been suggested as a virulence marker associated with the development of duodenal ulcer disease. However, the studies performed in different geographical areas have shown that there are variations in the prevalence of dupA and its association with H. pylori clinical outcomes. Our group did not observe associations between the presence of dupA and H. pylori clinical outcomes in Brazil. On the other hand, we observed 2 mutations in the sequence of dupA that lead to stop codons: a deletion of an adenine at position 1311 and an insertion of an adenine at position 1426 of the gene. Our aim was to evaluate associations of the presence of dupA with duodenal ulcer and gastric cancer, considering dupA-positive only those H. pylori strains that do not have the mutations in the gene sequence. We also evaluated the effect of infection with a strain carrying an intact dupA on the gastric mucosa histology and IL-8 gastric levels. Colonization with strains that had the intact dupA was negatively associated with gastric carcinoma (p=0.001, OR=0.32, 95% CI=0.16-0.66). The presence of dupA was also associated with an increased degree of antral mucosa inflammation (p=0.01) and with decreased corpus atrophy (p<0.01) as well as with increased gastric mucosa IL-8 levels (p=0.04). In conclusion, the infection with a H. pylori strain containing the dupA without the stop codon polymorphisms is associated with a lower risk of development of gastric carcinoma in Brazilian subjects.


Asunto(s)
Úlcera Duodenal/epidemiología , Infecciones por Helicobacter/complicaciones , Helicobacter pylori/patogenicidad , Polimorfismo Genético , Neoplasias Gástricas/epidemiología , Factores de Virulencia/genética , Adulto , Anciano , Brasil/epidemiología , Úlcera Duodenal/microbiología , Femenino , Mucosa Gástrica/patología , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Helicobacter pylori/genética , Humanos , Interleucina-8/metabolismo , Masculino , Persona de Mediana Edad , Neoplasias Gástricas/microbiología
3.
Mem Inst Oswaldo Cruz ; 105(5): 657-60, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20835612

RESUMEN

Helicobacter pylori infection is associated with peptic ulcer and gastric carcinoma. The oral cavity may be a reservoir for H. pylori; however, the results of studies on this subject are controversial. We employed single-step and nested polymerase chain reactions (PCR) to detect the presence of the vacA, ureA and 16S rDNA genes of H. pylori in the stomach, saliva and dental plaque of 30 subjects. The results were confirmed by sequencing. Nested 16S rDNA and ureA amplification was achieved in 80% of gastric, 30% of saliva and 20% of dental plaque specimens. Sequencing of 10, seven and four 16S rDNA products from stomach, saliva and dental plaque, respectively, showed > 99% identity with H. pylori. Sequencing of the other four oral cavity PCR products showed similarity with Campylobacter and Wolinella species. Additionally, the vacA genotype identified in the samples of different sites was the same within a given subject.H. pylori may be found in the oral cavity of patients with gastric infection, thus it could be a source of transmission. However, results obtained with detection methods based only on PCR should be interpreted with caution because other microorganisms that are phylogenetically very close to H. pylori are also present in the mouth.


Asunto(s)
Placa Dental/microbiología , Dispepsia/microbiología , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/aislamiento & purificación , Saliva/microbiología , Estómago/microbiología , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Biopsia , ADN Bacteriano/genética , ADN Ribosómico/genética , Femenino , Infecciones por Helicobacter/transmisión , Helicobacter pylori/genética , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa/métodos , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
4.
Mem. Inst. Oswaldo Cruz ; 105(5): 657-660, Aug. 2010. tab
Artículo en Inglés | LILACS | ID: lil-557225

RESUMEN

Helicobacter pylori infection is associated with peptic ulcer and gastric carcinoma. The oral cavity may be a reservoir for H. pylori; however, the results of studies on this subject are controversial. We employed single-step and nested polymerase chain reactions (PCR) to detect the presence of the vacA, ureA and 16S rDNA genes of H. pylori in the stomach, saliva and dental plaque of 30 subjects. The results were confirmed by sequencing. Nested 16S rDNA and ureA amplification was achieved in 80 percent of gastric, 30 percent of saliva and 20 percent of dental plaque specimens. Sequencing of 10, seven and four 16S rDNA products from stomach, saliva and dental plaque, respectively, showed > 99 percent identity with H. pylori. Sequencing of the other four oral cavity PCR products showed similarity with Campylobacter and Wolinella species. Additionally, the vacA genotype identified in the samples of different sites was the same within a given subject.H. pylori may be found in the oral cavity of patients with gastric infection, thus it could be a source of transmission. However, results obtained with detection methods based only on PCR should be interpreted with caution because other microorganisms that are phylogenetically very close to H. pylori are also present in the mouth.


Asunto(s)
Femenino , Humanos , Masculino , Persona de Mediana Edad , Placa Dental , Dispepsia , Infecciones por Helicobacter , Helicobacter pylori , Saliva , Estómago , Biopsia , Proteínas Bacterianas , Proteínas Bacterianas , ADN Bacteriano , ADN Ribosómico , Infecciones por Helicobacter/transmisión , Helicobacter pylori , Reacción en Cadena de la Polimerasa/métodos , Análisis de Secuencia de ADN
5.
Microbes Infect ; 11(12): 980-7, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19638314

RESUMEN

We evaluated whether polymorphisms in genes coding molecules linked to the innate and adaptive immune response are associated with susceptibility to Helicobacter pylori infection. IL1B-511C-->T, IL1B-31T-->C, IL1RN allele 2, IL2-330T-->G, TNFA-307G-->A, TLR2Arg677Trp, TLR2Arg753Gln, TLR4Asp299Gly, and TLR5(392STOP) polymorphisms were determined in 541 blood donors. IL2-330T-->G allele carriers had a decreased H. pylori infection risk (OR=0.63, 95% CI=0.43-0.93) after adjustment for demographic and environmental factors. Hence, we investigated whether the polymorphism is functional by evaluating IL-2 serum concentration in 150 blood donors and 100 children. IL-2 pro-inflammatory and anti-inflammatory properties were indirectly investigated by determining serum IFN-gamma and IL-10/TGF-beta levels. The polymorphism was associated with increased mean IL-2 levels in H. pylori-positive adults (2.65 pg/mL vs. 7.78 pg/mL) and children (4.19 pg/mL vs. 8.03 pg/mL). Increased IL-2 was associated with pro-inflammatory activity in adults (IFN-gamma=18.61 pg/mL vs. 25.71 pg/mL), and with anti-inflammatory activity in children (IL-10=6.99 vs. 14.17 pg/mL, TGF-beta=45.88 vs. 93.44 pg/mL) (p<10(-3) for all). In conclusion, in the context of H. pylori infection, IL2-330 T-->G polymorphism is functional and is associated with decreased risk of infection in adults.


Asunto(s)
Infecciones por Helicobacter/genética , Helicobacter pylori/inmunología , Interleucina-2/genética , Mutación Puntual , Polimorfismo Genético , Adulto , Donantes de Sangre , Niño , Preescolar , Femenino , Frecuencia de los Genes , Humanos , Inmunidad Innata , Interferón gamma/sangre , Interleucina-10/sangre , Interleucina-2/sangre , Interleucina-2/inmunología , Masculino , Análisis de Secuencia de ADN
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