Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serology has been used worldwide to detect Helicobacter pylori infection. Using an immunoblot assay with an antigen from strain ATCC 43579, we sought to determine the antibodies which were good markers of colonization and the antibody patterns associated with ulcers or atrophy. Out of 98 dyspeptic patients, 41 were colonized by H. pylori, based on a positive culture or on positive results of both a urease test and direct examination. These 41 patients were seropositive by an enzyme immunoassay, and 12 of them had ulcers and 29 had evidence of atrophy. Fifty-seven of the 98 patients were noncolonized. Twenty-five of the 57 had evidence of gastric atrophy, and 10 were seropositive; 5 of these 10 had ulcers. By Western blot analysis, 12 antibodies were significantly more frequent in sera from colonized patients, and they produced immunoreactive bands at 125, 87, 74, 66, 54, 48, 46, 42, 35, 30, 16 and 14 kDa. The presence of at least one band at 54, 35, or 42 kDa was the best marker of infection (sensitivity, 95%; specificity, 82%). In the group of colonized patients, none of the antibody patterns were correlated to gastric atrophy. Conversely, the presence of a band at 125, 87, or 35 kDa was statistically associated with the presence of an ulcer. The simultaneous presence of bands at 87 and 35 kDa predicted the risk of ulcers with 83% sensitivity and 69% specificity. By using CagA-positive and VacA-positive strains and CagA-negative and VacA-negative isogenic mutants, the antigens corresponding to the bands at 125 and 87 kDa were shown to be CagA and VacA, respectively. On the other hand, the 35-kDa antigen is a novel uncharacterized component of H. pylori. These results may help to optimize the composition of antigenic preparations for serologic detection of H. pylori colonization. Immunoblot assay would be useful for screening patients at high risk of ulcers.
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PMID:Use of immunoblot assay to define serum antibody patterns associated with Helicobacter pylori infection and with H. pylori-related ulcers. 954 11

Several studies have demonstrated that enzyme-linked immunosorbent assay is not a sensitive and specific method to diagnose Helicobacter pylori infection in children, especially in the younger ones. Since serum immune response can also be determined by immunoblotting and it permits the detection of antibodies to virulence factors such as CagA and VacA, we evaluated the accuracy of a commercial immunoblotting test to diagnose H. pylori infection and to assess the humoral immune response to different H. pylori antigens in 122 children who underwent upper gastrointestinal endoscopy. The presence of H. pylori was determined in antral biopsy specimens by culture, preformed urease test, and histological analysis. H. pylori was identified by microbiological and histopathological methods in 66 children (including all of the 21 who had duodenal ulcer). Antibodies to H. pylori were detected in 63 infected children and in 8 noninfected ones. The sensitivity, specificity, and positive and negative predictive values of the immunoblotting test were 95.5, 85.7, 88.7, and 94.1%, respectively. The number of immunoreactive bands increased with age (P = 0.003), and the bands of 35 kDa (P = 0.013); 89 kDa, the VacA antigen (P = 0.001); and 116 kDa, the CagA antigen (P = 0.00004) were more frequently observed in older children. The frequency of the bands of 89 kDa (P = 0.001) and 116 kDa (P = 0.03) was higher in children with duodenal ulcer than in H. pylori-positive children without the disease. In conclusion, the immunoblotting test appears to be useful for the diagnosis of H. pylori infection in children, even in the younger ones.
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PMID:Immunoblot analysis of humoral immune response to Helicobacter pylori in children with and without duodenal ulcer. 1079 98