Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Helicobacter pylori is prevalent worldwide, especially in developing countries, and is associated with several upper gastrointestinal diseases. Since it is present in over 90% of duodenal ulcer patients, empirical eradication in these patients is often recommended. In gastric ulcer patients, eradication is indicated only after the infection is confirmed. Testing for H. pylori infection should be carried out in patients with peptic ulcer hemorrhage, because eradication has been shown to reduce recurrent bleeding. Both H. pylori and NSAIDs are risk factors for peptic ulceration, and it is reasonable to screen for and eradicate H. pylori infection in peptic ulcer patients taking NSAIDs. H. pylori is a group I carcinogen for gastric adenocarcinoma, and should be eradicated for the primary prevention of this cancer. Eradication of this organism has been reported to result in regression of early low-grade mucosa-associated lymphoid tissue lymphoma. The role of H. pylori infection in the causation of gastroesophageal reflux and non-ulcer dyspepsia is not clearly established. Several tests are available for the diagnosis of H. pylori infection. These include invasive tests, such as histology, culture and urease test, and non-invasive tests, such as serology, urea breath test and stool antigen test. The choice of test is determined by clinical indication, pretest probability of infection, as well as the availability, cost, sensitivity and specificity of the test. H. pylori eradication therapy using proton pump inhibitor with clarithromycin and amoxycillin for 7 days has a success rate of 85-90%. Improved living standard and sanitation are vital in the control of H. pylori transmission and infection. Future development may include the use of vaccines against H. pylori, and therapies specifically targeting cagA strains of the bacteria.
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PMID:Eradication of Helicobacter pylori in clinical situations. 1559 83

The discovery of Helicobacter pylori has changed our understanding of the pathophysiology of peptic ulcer disease. An estimated one billion people harbour the organism worldwide but the highest prevalence is found in developing countries with up to 80% of people infected. The most favoured modes of transmission are faeco-oral and oral-oral. The mechanisms of H pylori-induced gastroduodenal disease include the provocation of local inflammatory reaction with the release of toxic cytokines, elevation of gastrin concentration and cytotoxic epithelial injury from the activity of urease and other enzymes produced by the bacterium. However, a large proportion of infected persons have no disease or are asymptomatic thereby suggesting that there may be other factors apart from H pylori infection necessary for ulcer formation. The simple finger prick test, a variant of serology and the newly developed ELISA-based Faecal Antigen Test hold the ace for large-scale epidemiological studies. The eradication of H pylori is now a very important goal of treatment of gastric and duodenal ulcers. Most H pylori eradication regimens combine anti-secretory agent, usually a proton pump inhibitor or H2-receptor antagonist and two antibiotics (usually, Clarithromycin and Amoxycillin or Metronidazole). Emergence of antibiotic resistance is worrisome but a quadruple therapy that incorporates bismuth may be used if the triple therapy fails.
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PMID:Helicobacter pylori and the pathogenesis of gastroduodenal disease: Implications for the management of peptic ulcer disease. 1638 Jul 42

The discovery of Helicobacter pylori (H. pylori) provided a possibility to cure effectively patients with peptic ulcers. Recent studies have shown varying susceptibility of H. pylori strains to antibiotics and increasing resistance to some of the recommended drugs. The purpose of the present study was to evaluate the efficacy of the currently recommended eradication schemes and to assess the increasing resistance of H. pylori strains to recommended antibiotics. Furthermore, the effect of probiotics (Lacidofil) on the efficacy of first-line treatment with amoxicillin and clarithromycin was analyzed. The study population consisted of 641 patients: 192 received amoxicillin with clarithromycin and proton pump inhibitor (PPI), 241 - tetracycline, tinidazole, bismuth and PPI, 53 - amoxicillin with clarithromycin and PPI supplemented with Lacidofil. The efficacy of eradication treatment was evaluated by the (13)C-urease breath test. The microbiological examination included 111 samples of H. pylori. The present study demonstrated low efficacy of the tetracycline, tinidazole, bismuth and PPI scheme i.e. 71.4%, moderate efficacy of the amoxicillin with clarithromycin and PPI scheme i.e. 85.9%, whereas the supplementation with Lacidofil significantly increased the efficacy of eradication to 94.3%. The microbiological examination revealed a relatively high level of primary resistance to clarithromycin (22.2%) and a high level to metronidazole (46.7%), with no resistance to amoxicillin. However, the most important finding is the high level of secondary resistance to clarithromycin and metronidazole (more than 66% in both cases). The present findings suggest the need for modification of the recommended eradication schemes.
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PMID:Efficacy of Helicobacter pylori eradication taking into account its resistance to antibiotics. 1703 11

This study investigated the influence of urease-positive non-Helicobacter pylori bacteria on the results of a urea breath test (UBT) to evaluate the diagnostic utility of a UBT using film-coated [(13)C]urea tablets. The UBT was performed in 102 patients treated with a proton pump inhibitor and antibiotics for the eradication of H. pylori. Urease-producing bacteria other than H. pylori were isolated and identified from the oral cavity and stomach. In 4/102 patients, the UBT gave false-positive results. These false-positive results were found to be caused by the presence of urease-positive bacteria in the oral cavity and stomach. Five bacterial species with urease activity (Proteus mirabilis, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae and Staphylococcus aureus) were subsequently isolated from the oral cavity and/or stomach. As there was no correlation between the in vitro urease activity of urease-positive non-H. pylori bacteria and the UBT value, and all of the patients with a false-positive UBT result were suffering from atrophic gastritis, it is possible that the false-positive results in the UBT were a result of colonization of urease-positive bacteria and gastric hypochlorhydric conditions. Thus, for the diagnosis of H. pylori infection using a UBT, the influence of stomach bacteria must be considered when interpreting the results.
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PMID:Urease-positive bacteria in the stomach induce a false-positive reaction in a urea breath test for diagnosis of Helicobacter pylori infection. 1856 38

This study was conducted to determine the prevalence of Helicobacter pylori (H. pylori) and its associated factors among patients with peptic ulcer disease in Taiping Hospital. Consecutive peptic ulcer disease patients who had undergone esophagogastro-duodenoscopy were included. The H. pylori status was assessed by the rapid urease test. We excluded those who had active bleeding, a perforated peptic ulcer, severe vomiting, a history of gastric surgery, peptic ulcer disease or renal or liver diseases, carcinoma of the stomach, and recent use of antibiotics or proton pump inhibitors. Socio-demography, H. pylori status, medication history and other relevant clinical data were collected from case notes. A total of 416 subjects were selected, 49.7% were positive and 50.3% were negative for H. pylori infection. There were significant associations between H. pylori and age, ethnicity, smoking status and NSAID usage. However, there were no significant relationships between H. pylori status and gender or type of peptic ulcer. Multiple logistic regression showed that other ethnicities than Malays and smokers had a higher risk of H. pylori. Our prevalence rate was low and the identified risk factors were consistent with previous studies. Ethnic differences may be related to genetic and sociocultural behaviors. Quitting smoking may benefit peptic ulcer patients with H. pylori infection.
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PMID:Helicobacter pylori infection in peptic ulcer disease: the importance of smoking and ethnicity. 1861 53

The Helicobacter pylori (Hp) infection is common. However, only 10-20% of infected individuals require antibacterial treatment. The main indications to such treatment are peptic ulcer disease, atrophic gastritis, dyspeptic symptoms, previous surgical procedure for gastric cancer, family history of gastric cancer and low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The treatment may also be undertaken at the patient's request. To detect the infection the urease test (when the patient has indications for gastroscopy), the urea breath test or serologic test are most commonly used. A standard treatment of Hp infection consists of a 7-day administration of one of the proton pump inhibitors and 2 out of 3 antibiotics such as amoxicillin, clarithromycin and metronidazole. After failure of the first-line treatment, the recommended second choice treatment is a quadruple treatment regimen consisting of bismuth salts, tetracycline, metronidazole and proton pump inhibitor. European guidelines (Maastricht III) allow the use of the quadruple treatment regimen already as the first choice treatment and therapy prolongation up to 14 days. Ineffectiveness of the second-line treatment is an indication for antimicrobial susceptibility testing. New antibiotics used for Hp eradication are levofloxacin and rifabutin. Eradication treatment should be obligatorily assessed with the use of the urease or breath test only in patients with peptic ulcer bleeding. The current guidelines do not envisage an active search for Hp infection in an asymptomatic population and treating people infected with this bacterium, for gastric cancer prevention.
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PMID:Clinical aspects of Helicobacter pylori infection. 1871 38

Helicobacter pylori is an important pathogen worldwide. Accurate diagnosis and appropriate therapy is important in clinical practice. Invasive tests that accurately identify current infection include the biopsy urease test and histology. The best noninvasive tests for diagnosis include the urea breath test and stool antigen testing. Proton pump inhibitor therapy can lead to false-negative H. pylori test results, and treatment should be stopped for 1-2 weeks prior to testing if possible. In the setting of bleeding peptic ulcer disease, urea breath testing is recommended to rule out a false-negative biopsy test result if needed. The current recommendations for when to test for H. pylori vary around the world. Well-accepted indications include active and past ulcer disease, and gastric-mucosa associated lymphoid tissue lymphoma. There is no universal agreement regarding whether all patients with functional dyspepsia should be tested and treated, although this is an evidence-based recommendation. There is also evidence that H. pylori eradication prevents peptic ulcer disease in those starting NSAIDs long term. Primary treatment remains triple therapy with 10-14 days probably being superior to shorter courses of therapy. Quadruple therapy is recommended if standard triple therapy fails. Salvage therapies with levofloxacin, rifabutin or furazolidone have been identified. Novel approaches to treatment include sequential therapy and use of adjuvants.
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PMID:Helicobacter pylori: testing and treatment. 1907 36

We report the case of a patient with gastroesophageal reflux disease who developed gastric atrophy and intestinal metaplasia (IM) while on 20-year treatment with proton pump inhibitors. This is perhaps the first report in human beings. A 74-year-old man, who presented with heartburn, showed abnormally high gastric pH (average 6.57) on 24-hour dual channel pH-metry even after discontinuing acid suppressive drugs for one month. No significant esophageal acid exposure was noted, which may be related to an impairment of the acid secreting capacity of the stomach (percentage time esophageal pH<4 during 24-h period 0.3%). Upper gastrointestinal endoscopy was normal except for the prominent submucosal vessels in the body and fundus suggesting gastric atrophy. Histopathological examination of multiple biopsies from the body and antrum of stomach showed signs of gastric atrophy and IM. Rapid urease test and histopathology of gastric biopsies were negative for Helicobacter pylori. Anti-H.pylori IgG ELISA however, was positive. Patient was asked to stop all anti-secretory drugs and only prokinetics were prescribed following which his symptoms markedly improved. On follow-up, in April 2007, he developed symptoms of peripheral neuropathy; serum vitamin 812 level was low. He responded to parenteral vitamin 812 therapy. 24-h dual channel pH-metry repeated after one and a half years showed persistently high gastric pH (average pH 6.76). The patient remained well after discontinuing proton pump inhibitors and continuing prokinetics and vitamin B12 injections.
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PMID:Gastric atrophy and intestinal metaplasia in a patient on long-term proton pump inhibitor therapy. 1911 12

The main conclusions drawn from the presentations related to Helicobacter pylori at Digestive Diseases Week 2008 are summarized. Several strains of H. pylori frequently infect the same patient, and consequently samples for culture should be obtained from the gastric antrum and body. The test-and-treat strategy in dyspepsia is as effective as empirical antisecretory therapy and is probably cheaper. The benefit of eradication therapy in patients with uninvestigated dyspepsia, although small, seems to be lasting. Eradication in the general population seems to reduce the development of dyspeptic symptoms in the long term and consequently could be cost-effective. The prevalence of H. pylori infection in peptic ulcer is decreasing and the frequency of idiopathic ulcers is increasing. Patients with H. pylori-negative bleeding ulcers have a high probability of hemorrhagic recurrence and should therefore receive maintenance antisecretory therapy. H. pylori eradication reduces the incidence of gastric adenocarcinoma, which could warrant a screening and treatment strategy for this infection in the general population in high risk areas. H. pylori infection should be eradicated in patients undergoing endoscopic mucosal resection for early gastric cancer. To prevent the development of gastric cancer, eradication therapy should be administered early, before gastric atrophy develops. H. pylori-negative and H. pylori-positive gastric lymphomas have an equally favorable prognosis. New diagnostic techniques have been developed: the ultra-rapid urease test, a simpler 14C-urea breath test, and an ELISA method for rapid bacterial susceptibility determination. In patients with gastrointestinal bleeding, the 13C-urea breath test performed immediately after emergency gastroscopy allows early diagnosis of infection. Eradication regimens with double doses of proton pump inhibitors are more effective than those with standard doses. "Sequential" therapy is more effective and cheaper than classical triple-drug therapy, although the superiority of administering therapy sequentially rather than concomitantly has not been established. In penicillin-allergic patients, a combination with levofloxacin and clarithromycin is a promising alternative in rescue therapy. Second-line rescue therapy with levofloxacin is effective and is also simpler and better tolerated than quadruple-drug therapy. The rate of quinolone resistance is increasing as a result of the widespread use of these antibiotics. Third-line treatment with levofloxacin is also a promising alternative. Even after the failure of three previous treatments, a fourth empirical rescue therapy (with levofloxacin or rifabutin) can be effective in more than half of patients. The annual recurrence rate of H. pylori infection is approximately 3% in developed countries and is higher than 10% in developing countries.
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PMID:[Helicobacter pylori-related diseases: dyspepsia, ulcer and gastric cancer]. 1943 62

Helicobacter pylori is associated with various gastroduodenal diseases such as peptic ulcer, functional dyspepsia, MALT lymphoma and distal gastric cancer. Diagnosis of H. pylori can be established by non-invasive ((13C)urea breath test, stool antigen test, serology) and invasive (histology, rapid urease test, culture) tests. In adults, culture and susceptibility testing should or must be performed after failing of first-line therapy in case of a control endoscopy and before third-line therapy, respectively. Peptic ulcer and gastric MALT lymphoma represent obligatory indications for eradication therapy. Other potential indications are functional dyspepsia, prevention of gastric cancer in individuals being at risk, and before starting treatment with traditional non-steroid antiphlogistics. First-line therapy is performed with a 7-days combination of proton pump inhibitor with clarithromycin and amoxicillin or metronidazole. In second-line therapy levofloxacin and rifabutin are good rescue antibiotics.
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PMID:[Helicobacter pylori]. 1960 71


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