Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.5 (urease)
 7,257 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to evaluate the diagnostic accuracy of serologic tests and to verify whether specific IgG antibody can be used in the diagnosis of Helicobacter pylori infection in children without endoscopy. Serologic and endoscopic examinations were performed in 310 children (1 month-15 years) with gastrointestinal symptoms. Serologic outcomes were compared with the results of rapid urease test, histologic examination, and culture. The prevalence of H. pylori infection was 21.0% and the seropositivity of H. pylori was 24.2% in these symptomatic children. Serologic examination for diagnosis of H. pylori showed a sensitivity of 94.9% and a specificity of 92.4%, diagnostic reliability equal to the rapid urease test and histologic examination in children. The serum IgG test is a useful tool for the diagnosis of H. pylori infection, especially in children.
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PMID:The role of serology in the diagnosis of Helicobacter pylori infection in children. 758 16

We examined the effects of lansoprazole and famotidine on gastric basic fibroblast growth factor (bFGF) levels and ulcer healing in patients with gastric ulcer. Sixteen patients with active gastric ulcer were divided into two groups and received treatment with lansoprazole 30 mg/day or famotidine 40 mg/day. They were examined endoscopically at 2, 4, and 8 weeks to measure gastric bFGF levels at the ulcer margin and to assess ulcer healing. Helicobacter pylori infection was determined by a rapid urease test. The two groups were comparable with regard to age, male:female ratio, H. pylori infection rates, and bFGF levels. During treatment, bFGF levels did not change significantly in the famotidine group, whereas they increased by a factor of 2.2 to 2.6 in the lansoprazole group. Cumulative healing rates were also significantly lower in the famotidine group than in the lansoprazole group. These results indicate that lansoprazole increases tissue bFGF levels and promotes gastric ulcer healing in humans.
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PMID:Gastric ulcer healing and basic fibroblast growth factor: effects of lansoprazole and famotidine. 759 20

Helicobacter pylori infection is characterized by an inflammatory response in the gastric epithelium, the intensity of which appears to be type-strain specific. Infections caused by Type 1 H. pylori organisms, i.e., those expressing VacA (the cytotoxin) and CagA (the cytotoxin-associated protein), are associated with a strong polymorph mucosal infiltration in vivo, and with increased secretion of interleukin-8 by epithelial cells. The inflammatory potential of Type II strains (non-cytotoxic, VacA- and CagA-negative) is probably less pronounced. The small urease subunit, porins, and other substances produced by H. pylori show neutrophil chemotactic activities in vitro. These bacterial components promote the adhesion of polymorphs to endothelial cells and stimulate polymorphs to generate oxygen reactive metabolites. This can severely damage the gastroduodenal mucosa.
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PMID:Progress in defining the inflammatory cascade. 760 Jan 33

Helicobacter pylori is an important etiologic agent of gastroduodenal disease. In common with other organisms, H. pylori bacteria express heat shock proteins that share homologies with the GroES-GroEL class of proteins from Escherichia coli. We have assessed the heat shock proteins of H. pylori as potential protective antigens in a murine model of gastric Helicobacter infection. Orogastric immunization of mice with recombinant H. pylori GroES- and GroEL-like proteins protected 80% (n = 20) and 70% (n = 10) of animals, respectively, from a challenge dose of 10(4) Helicobacter felis bacteria (compared to control mice, P = 0.0042 and P = 0.0904, respectively). All mice (n = 19) that were immunized with a dual antigen preparation, consisting of H. pylori GroES-like protein and the B subunit of H. pylori urease, were protected against infection. This represented a level of protection equivalent to that provided by a sonicated Helicobacter extract (P = 0.955). Antibodies directed against the recombinant H. pylori antigens were predominantly of the IgG1 class, suggesting that a type 2 T-helper cell response was involved in protection. This work reports a protein belonging to the GroES class of heat shock proteins that was shown to induce protective immunity. In conclusion, GroES-like and urease B-subunit proteins have been identified as potential components of a future H. pylori subunit vaccine.
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PMID:The GroES homolog of Helicobacter pylori confers protective immunity against mucosal infection in mice. 760 21

Helicobacter mustelae infects the ferret stomach and provides an opportunity to study pathogenic determinants of a Helicobacter species in its natural host. We constructed an isogenic urease-negative mutant of H. mustelae which produced no detectable urease and showed a reduced acid tolerance. This mutant provides an opportunity to further evaluate the role of urease in the pathogenesis of Helicobacter infection.
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PMID:Construction and characterization of an isogenic urease-negative mutant of Helicobacter mustelae. 764 13

Helicobacter pylori infection is associated with gastric mucosal damage and the infiltration of neutrophils. Myeloperoxidase from neutrophils produces hypochlorous acid, which yields monochloramine in the presence of ammonia produced by urease enzyme of Helicobacter pylori. The target cells of gastric mucosal damage are gastric mucosal cells and endothelial cells. We therefore tested the hypothesis that ammonium, hypochlorous acid, and monochloramine damage the target cells. We studied the in vitro cytotoxic effects of ammonium chloride, sodium hypochlorite, monochloramine, and activated neutrophils on the target cells. Cytotoxicity was measured by a 51Cr-release assay. Ammonium chloride, sodium hypochlorite, and monochloramine were toxic to labeled cells in a concentration dependent manner. The toxicity of these agents was in the order monochloramine > sodium hypochlorite >> ammonium chloride. Incubation of labeled cells with activated neutrophils, Helicobacter pylori, and urea resulted in cytolysis. These cytotoxicities were significantly inhibited by the scavenger of hypochlorous acid, taurine. Monochloramine is more toxic to the target cells than ammonium chloride. Although ammonium chloride at neutral pH by itself has little direct damaging effect on the gastric mucosa, it is damaging to the gastric mucosa through a reaction with hypochlorous acid, suggesting that it plays a role in Helicobacter pylori-associated gastric damage.
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PMID:Mechanism of Helicobacter pylori-associated gastric mucosal injury. 778 56

Recently many reports have shown a strong association between Helicobacter pylori infection in the stomach and recurrent peptic ulcer. Moreover, prospective cohort serological studies showed that H. pylori infected individuals have significantly increased rate of gastric cancer in the USA. H. pylori is a gram-negative spiral organism which has urease activity and produces ammonia and CO2 from urea, and nestles in the gastric pits and overlaying mucus gel layer. Many diagnostic methods of H. pylori infection are available; ie bacterial culture, 13C-urea breath test, histology, serum IgG antibody against H. pylori. We developed a new method, ie tissue IgA antibody against H. pylori and detection of H. pylori DNA in the gastric juice by PCR method. Triple therapies with metronidazole, bismuth compounds, and amoxicillin or tetracyclin are difficult to use in Japan because of their sever side effects. Thus, new methods with proton pump inhibitor (PPI) and amoxicillin have been introduced. We treated 14 patients of whom were H. pylori positive-active peptic ulcer with 30 mg/day of lansoprazole, a new PPI, plus 1,500 mg/day of amoxicillin for 2 weeks and 8 (57%) patients were eradicated. Gastric carcinogenesis are multi-steps and multifactorials process. Hypothetical sequence of intestinal type of gastric cancer is that superficial gastritis-->atrophic gastritis-->intestinal metaplasia-->dysplasia-->gastric cancer and H. pylori infection may play a role in the early stage of the sequence. We examined mucosal IgA antibody against H. pylori in chronic gastritis and intestinal metaplasia detected by the Tes-Tape method in 25 resected specimens after gastrectomy for gastric cancer. Positivity rates of tissue H. pylori IgA antibody were lower in the mucosa of intestinal metaplasia than in non-metaplastic gastric mucosa and were negative in carcinoma. Causal relationship between H. pylori infection and gastric cancer is not proven and factors other than H. pylori infection are also important in the gastric carcinogenesis. Finally we introduce 2 reports: (1) NIH Consensus Conference: Helicobacter pylori in peptic ulcer disease (JAMA. 1994; 272: 65-69). The consensus panel concluded that 1. ulcer patients with H. pylori infection require treatment with antimicrobial agents in addition to antisecretory drugs whether on first presentation with the illness or on recurrence; 2. the value of treating nonulcerative dyspepsia patients with H. pylori infection remains to be determined; and 3. the interesting relationship between H. pylori infection and gastric cancer requires further exploration. (2) World Health Organization: Working Group Meeting (Reported in World Congress of Gastroenterology, Los Angeles, 1994). H. pylori plays a causal role in the chain of events leading to cancer of the stomach. Group I: definite carcinogen.
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PMID:[Helicobacter pylori in peptic ulcer and gastric cancer]. 785 88

Diagnosis and successful eradication of Helicobacter pylori infection has been shown to be significantly related to symptom improvement in patients affected by chronic gastritis, duodenal and gastric ulcer. There is, therefore, an increasing need for the development of new, easy to use, reliable and non-invasive techniques to detect this organism. One such test is Flex-Sure (SmithKline Diagnostics Inc., United States), a new, rapid immunochromatographic test which requires a drop of the patient's serum to be placed on the absorbent pad of a strip. If specific antibodies to H. pylori are present a red colour line appears. The present study compared Flex-Sure with a homologous quantitative immunoenzymatic test (HM-CAP, EPI, US) using the same antigen (high molecular weight protein), the second generation GAP test (Bio-Rad, USA), a rapid urease test, culture and histology in a cohort of dyspeptic patients. We produced a semiquantitative visual scale with which to perform this comparison. Our results show that Flex-Sure possesses a sensitivity of 96.1%, a specificity of 73.9%, an overall accuracy of 78.8%, a positive predictive value of 72% and a negative predictive value of 91.6%. It showed a highly significant correlation with histological and cultural results (P < 0.001), and with the other serological tests (P < 0.0001). Based on our data we conclude that Flex-Sure may yield quick (within 4 min), simply readable, qualitative, and according to our colourimetric scale, even semiquantitative results. Furthermore, it does not require any sample dilution, any particular equipment, or any specialized training for the operator.
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PMID:Serodiagnosis of Helicobacter pylori: evaluation of a rapid, miniaturized immunochromatographic test. 785 77

Urease is an important virulence factor for gastric Helicobacter spp. To elucidate the efficacy of individual urease subunits to act as mucosal immunogens, the genes encoding the respective urease subunits (UreA and UreB) of Helicobacter pylori and Helicobacter felis were cloned in an expression vector (pMAL) and expressed in Escherichia coli cells as translational fusion proteins. The recombinant UreA and UreB proteins were purified by affinity and anion-exchange chromatography techniques and had predicted molecular masses of approximately 68 and 103 kDa, respectively. Western blotting (immunoblotting) studies indicated that the urease components of the fusion proteins were strongly immunogenic and were specifically recognized by polyclonal rabbit anti-Helicobacter sp. sera. The fusion proteins (50 micrograms) were used, in combination with a mucosal adjuvant (cholera toxin), to orogastrically immunize mice against H. felis infection. Gastric tissues from H. felis-challenged mice were assessed by the biopsy urease test and by histology. In mice immunized with recombinant H. felis UreB, 60% of animals (n = 7) were histologically negative for H. felis bacteria after challenge at 17 weeks. This compared with 25% (n = 8) for mice immunized with the heterologous H. pylori UreB antigen. Neither the homologous nor the heterologous UreA subunit elicited protective responses against H. felis infection in mice. The study demonstrated that a recombinant subunit antigen could induce an immunoprotective response against gastric Helicobacter infection.
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PMID:Recombinant antigens prepared from the urease subunits of Helicobacter spp.: evidence of protection in a mouse model of gastric infection. 792 78

A method for measurements of blood antigen-binding lymphocytes sensitized to Helicobacter antigens is suggested. Use of this method together with urease test will improve Helicobacter infection detection rate by 22%.
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PMID:[A complex method of detection of Helicobacter pylori in patients with duodenal ulcer]. 795 11


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