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)

The role of Helicobacter pylori in gastric carcinogenesis is a subject of an increasing interest. In this report we describe a prospective study on the resected stomachs to establish the prevalence of H. pylori in different types of gastric carcinoma. The material consisted of 62 consecutive patients operated on stomach adenocarcinomas Fifty six percent of the patients were intestinal type, 34%--diffuse type and 10%--mixed type. The presence of H. pylori was studied in specimens from surgically removed stomachs. The conformation of the bacterial infection was done by means of rapid urease test, microbiological culture, Warthin-Starry and immunohistochemical staining. The overall prevalence of H. pylori infection was 69% (43/62). There was a statistically significant difference in the infection rates between the types of carcinoma--75% in the intestinal type and 62% in the diffuse type. The most sensitive was immunohistochemical staining. The bacterial colonies were cumulated far from the tumor tissue. In cardiac cancer the most intense of infection was an antrum and lower part of gastric body. In opposite; in antrum and pylorus cancer the scope of colonisation increased in fundus and subcardiac region with statistical signification. We could not detect H. pylori in the tumor tissue itself as in the normal mucosa of the stomach. In gastric antrum the most intense colonisation was detected on mucosal atrophy, but in the upper part of the stomach--on the mucosal metaplasia.
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PMID:Topography of Helicobacter pylori infection in gastric cancer patients. 944 64

Genetic diversity in Helicobacter pylori strains may affect the function and antigenicity of virulence factors associated with bacterial infection and, ultimately, disease outcome. In this study, DNA diversity of H. pylori isolates was examined by analysis of vacA genotypes and by restriction fragment length polymorphism (RFLP) analysis of H. pylori-associated genes (vacA, cagA,flaA, ureAB, and ureCD). Thirty-seven H. pylori isolates from 26 patients were successfully classified into distinct vacA allelic genotypes. The signal sequence allele sl (31 of 37) predominated over the s2 allele (6 of 37) and was significantly associated with the occurrence (past or present) of gastric ulcers. A novel midregion allele, designated as m3, has been identified in two H. pylori isolates which could not be typed with midregion allele m1- or m2-specific primers. Additionally, significant nucleotide diversity yielding different amino acid sequences was demonstrated by DNA sequencing of vacA fragments from clinical isolates of H. pylori. Furthermore, RFLP analysis of 45 H. pylori isolates (including 15 paired isolates) obtained from antrum and corpus biopsy specimens from 30 individual patients showed remarkably high interhost diversity (one patient, one H. pylori strain) and intrahost identity in gene sequences coding for VacA, CagA, flagellin, and urease. Only in a single patient was a minor genotypic variation at different anatomic sites within the stomach identified. These data warrant the detailed analysis of the effect of genetic diversity on the function and antigenicity of H. pylori-associated virulence factors.
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PMID:vacA genotypes and genetic diversity in clinical isolates of Helicobacter pylori. 952 Nov 35

Many diagnostic tests are available to establish Helicobacter pylori infection status. Most of the tests are accurate though none works perfectly, and no gold standard for diagnosis exists. Newly developed serum immunoassay kits can substitute for laboratory-based enzyme-linked immunosorbent assays, but whole blood immunoassays do not yet demonstrate adequate performance characteristics. Serologic diagnosis of H. pylori remains the most cost-effective option and should be utilized to establish initial infection in the majority of cases. If rapid urease testing is performed at endoscopy, negative results can be confirmed with a subsequent serologic test in those patients with a high probability of infection. Obtaining additional gastric tissue at endoscopy to evaluate for bacterial infection is reasonable if specimens are being taken for a mucosal defect. Confirmation of bacterial eradication cannot be justified for all post-treatment patients at present due to the expense. It is important to test for cure in those patients with complicated ulcer disease and those with recurrent symptoms after therapy.
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PMID:Accuracy and economics of Helicobacter pylori diagnosis. 1037 52

Hardly any other bacterial infection can be diagnosed with a similar variety of non-invasive and invasive tests as infection with H. pylori. Efficacy and specificity of well-proven tests such as urease test in biopsy specimens, histology, culture, and 13C breath test have been uniformly evidenced in numerous studies. Novel tests include molecular microbiological procedures, providing new opportunities for rapid detection of virulence factors and resistance genes, as well as antigen detection in feces. Though some open questions still need to be clarified, the latter test will gain major importance in the future. With the availability of the breath test and antigen detection in stool the need for the use of serological tests has been reduced, all the more so as the majority of the available quick tests have been shown to be of inadequate reliability. Well defined indications for the treatment of H. pylori infections are a major prerequisite for a reasonable use of this diagnostic armory.
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PMID:[Diagnosis of Helicobacter pylori infections]. 1098 79

Helicobacter pylori is one of the most common causes of chronic bacterial infection in humans, and it is associated with many diseases of the upper gastrointestinal tract. The 13C urea breath test (13C-UBT) is a simple, non-invasive and global test for Helicobacter pylori detection. The test reflects the hydrolysis of 13C-labelled urea by Helicobacter pylori urease. The 13C-UBT is the gold standard test for Helicobacter pylori infection. Since the original description (in 1987) several modifications of 13C-UBT have been published to simplify and optimise the test. However, neither Standardised European Protocol nor Standard US Protocol were accepted. This paper gives the methodology of the 13C-UBT based on eur own study and on the review of the literature.
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PMID:[Diagnosis of Helicobacter pylori with the 13C-labeled urea breath test: study methodology]. 1126 17

Urease has been suggested to be essential for colonization and pathogenesis of Helicobacter pylori infection. In the present study, we evaluated the effects of urease inhibitors [acetohydroxamic acid (AHA) and flurofamide (FFA)] on H. pylori-induced gastritis in Mongolian gerbils. Animals were orally inoculated with H. pylori, and given urease inhibitors in their diet throughout the experimental period of six weeks or four weeks, starting from two weeks after H. pylori inoculation. With the administration of AHA at doses of 100, 500, and 2500 ppm throughout the experimental period, H. pylori-induced gastritis in animals was decreased in a dose-dependent manner, significantly so at 2500 ppm. Suppression of gastric lesions was also evident in animals administered 2500 ppm AHA after the H. pylori infection. Bacterial infection rates were reduced to 40-50% of the control value of 100%, by the highest dose of AHA. The potent urease inhibitor, FFA, also caused marked amelioration of H. pylori-associated gastritis on administration at 100 ppm throughout the six-week experimental period or for four weeks after H. pylori infection. Animals treated with FFA had few visible gastric lesions, and the proportion infected with H. pylori was reduced to less than 10%. Since antibiotic-resistant strains of H. pylori have become a serious problem, nonantibiotic urease inhibitors may be very useful to control H. pylori-associated gastroduodenal disease.
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PMID:Marked reduction of Helicobacter pylori-induced gastritis by urease inhibitors, acetohydroxamic acid and flurofamide, in Mongolian gerbils. 1145 54

Since Marshall's discovery before 20 years, Helicobacter pylori (H. pylori) infection is reportedly to be associated with a variety of clinical outcomes including peptic ulcer disease and gastric cancer. The first step of the H. pylori colonization might be its adhesion to the surface epithelial cells, which evokes gastric inflammatory events initiated by neutrophil recruitment from the microcirculation. Mongolian gerbil is one of the suitable animal models for H. pylori infection, which exerts gastric ulcer and cancer with its bacterial infection. In H. pylori-colonized gerbils, extensive levels of microvascular leukocyte adhesion and migration into the parenchymal side and significant levels of inflammatory cell infiltration are encountered. Bacterial urease not only neutralizes gastric luminal acid, but also plays as an adhesion factor to the surface epithelium. Recently, such an adhesion to the epithelium is reported to be important for bacterial type IV secretory system, which intermediates Cag A injection into the epithelial cells. Then, multiple chemokine and cytokine networks are activated and mucosal inflammatory lesion formation would be completed. In the long-term colonization of H. pylori, gastric mucosal cell turnover would be modified due to persistent inflammation and then such deregulation of cell turnover might link to the precancerous lesion formation.
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PMID:Gastric mucosal response to Helicobacter pylori. 1252 36

Helicobacter pylori is one of the most common chronic bacterial infection in humans linked to acid peptic diseases, gastric carcinomas and lymphomas. The bacilli produces large amounts of urease and this property has formed the basis of detection of H. pylori by the Christensen's urease test. Where endoscopy is not clinically indicated, serology may be used to establish the diagnosis. This study was undertaken to diagnose H. pylori with the help of Christensen's urease test on endoscopic biopsy specimens & correlated with the detection in Sera, of IgG antibodies against H. pylori, by ELISA technique. The study was conducted on 100 patients suffering from acid peptic disorders out of which 40 (40%) tested positive for H. pylori both by urease and serology. Christensen's urease and ELISA were found to have sensitivities of 85.7% & 90.9% and specificities of 96% and 87.5% respectively. Christensen's urease was taken as a standard method of diagnosis and its correlation with ELISA worked out to (+1) which meant there was a strong positive association between both the tests. Hence either test could be used for primary diagnosis of H. pylori instead of histopathological study and/or culture of H. pylori.
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PMID:Role of ELISA in H. pylori detection and its correlation with urease test. 1502 27

Diagnosis and treatment of stomach ulcer associated with helicoid-bacterial infection and with hemorrhage are discussed in the paper. The many-year observations show that the risk of relapsing hemorrhage is high in patients with the above diagnosis. Eradication of the causative agent by using the modern therapeutic schemes cuts significantly the rate of such relapses. The most effective method of monitoring the infection and eradication results is suggested, i.e. urease test combined with microbiological diagnosis involving the method of polymerase chain reaction.
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PMID:[Diagnosis and treatment of Helicobacter infections in patients with stomach ulcer associated with hemorrhage]. 1532 56

Primary gastric lymphoma, an uncommon gastric tumor caused by infection with Helicobacter pylori, is rarely associated with gastric amyloidosis. Chronic bacterial infection is known to cause amyloidosis. We report a 53-year-old man who had an antral and duodenal mass with narrowing and ulceration on endoscopy and CT scan; endoscopic biopsy revealed gastric amyloidosis. Rapid urease test and serology for H. pylori were positive. Histology of resected specimen of distal stomach revealed primary gastric lymphoma, amyloid deposits and spiral organisms suggestive of H. pylori. Rectal biopsy was negative for amyloid. He remained well on follow-up after surgery and eradication of H. pylori.
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PMID:Primary gastric lymphoma and Helicobacter pylori infection with gastric amyloidosis. 1676 51


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