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

A 53-year-old woman was diagnosed as having idiopathic thrombocytopenic purpura (ITP) in 1990, and treated with prednisolone and splenectomy, which did not result in remission. In November 2000, gastrointestinal endoscopy showed superficial gastritis, and Helicobacter pylori infection was revealed by the rapid urease test and histologic examination. After eradication of Helicobacter pylori by amoxicillin, clarithromycin and lansoprazole, the patient's platelet count was increased from 24 x 10(9)/l to 134 x 10(9)/l and platelet-associated IgG (PAIgG) was decreased from 695 ng/10(7) cells to 33 ng/10(7) cells. This case suggests that eradication of Helicobacter pylori may be useful for treating some patients with refractory ITP.
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PMID:[Successful treatment of refractory idiopathic thrombocytopenic purpura by eradication of Helicobacter pylori]. 1182 23

Helicobacter pylori (H. pylori) is a spiral shaped bacterium that resides in the stomach mucosa. Isolation of H. pylori from the stomach mucosa changed the erstwhile widely held belief that the stomach contains no bacteria and is actually sterile. Once H. pylori is safely ensconced in the mucus, it is able to neutralize the acid in the stomach by elaborating an enzyme called urease. Urease converts urea, of which there is an abundant supply in the stomach (derived from saliva and the gastric juice), into bicarbonate and ammonia, which are strong bases. These bases form a cloud of acid-neutralizing chemicals in the vicinity of the organisms, protecting them from the acid in the stomach. This urea hydrolysis reaction is utilized for the diagnosis of H. pylori infection in the urea breath test (UBT) and the rapid urease test (RUT). In Japan, both invasive tests, such as bacterial culture, histopathology and RUT, and non-invasive tests such as UBT and serology are conducted for the diagnosis of H. pylori infection. For confirming the results of eradication therapy, UBT is considered to be the most sensitive and specific. In order to treat H. pylori infection, a new one-week triple therapy regimen (lansoprazole or omeprazole + amoxicillin + clarithromycin) has been approved for use in patients with peptic ulcer disease in Japan. As for H. pylori eradication in the case of other diseases in which the bacterium has been implicated (e.g., chronic atrophic gastritis, gastric MALT lymphoma, gastric cancer, non-ulcer dyspepsia, chronic urticaria, idiopathic thrombocytopenic purpura (ITP)), further basic and clinical investigation is required.
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PMID:Current consensus on the diagnosis and treatment of H. pylori-associated gastroduodenal disease. 1452 49

The relationship between Helicobacter pylori (H. pylori) and gastric diseases (e.g. peptic ulcer, MALT lymphoma, and stomach cancer) has been widely accepted. Recent studies have also suggested an association between H. pylori infection and idiopathic thrombocytopenic purpura (ITP). In this study, an H. pylori eradication treatment was administered to 20 ITP patients and elucidated for its effectiveness. Among those 20 patients, H. pylori infection was confirmed in 17 (85%) through a C14 urea breath test, a rapid urease test, or a culture examination of a biopsied sample obtained by gastrointestinal endoscopy. Although the other 3 were negative to H. pylori, the H. pylori eradication treatment was also attempted because no other effective treatments had been established at the time of this study. In the H. pylori eradication treatment, lansoprazole (LPZ) 60 mg bid, amoxicillin (AMPC) 1500 mg bid, and clarithromycin (CAM) 400 mg bid were given to each patient for 7 days. For 4 cases, CAM was replaced with metronidazole (MNZ) 750 mg bid. The patients whose H. pylori infection was not eradicated after the first treatment received the re-eradication treatment with LPZ 60 mg bid, AMPC 1500 mg bid, and MNZ 750 mg bid for 7 days. After the treatments, the success of eradicating H. pylori was confirmed in all 17 H. pylori positive patients. In addition, platelet recovery was obtained in 11/20 patients (55%), which included 2 H. pylori negative patients and 2 patients whose H. pylori eradication was not successful after the first treatment. No relationship was found between the eradication effectiveness and the following clinical parameters: age, gender, previous therapies, disease duration, presence of anti-nucleus antibody, endoscopic atrophic change in the stomach, or kinds of antibiotics used for the treatment. These results support the efficacy of an H. pylori eradication treatment for ITP patients. A noteworthy result of this study was that an increase of platelet count was observed not only in H. pylori positive ITP patients, but also in 2 out of 3 H. pylori negative ITP patients after H. pylori eradication. Further studies are required to elucidate the efficacy of H. pylori eradication therapy in the patients negative for H. pylori.
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PMID:[Evaluation of the efficacy of an Helicobacter pylori eradication treatment for idiopathic thrombocytopenic purpura patients]. 1557 Aug 69

Besides various gastroduodenal diseases, Helicobacter pylori infection may be involved in autoimmune disorders like rheumatoid arthritis (RA) or idiopathic thrombocytopenic purpura. Such autoimmune disorders are often associated with autoreactive antibodies produced by B-1 cells, a subpopulation of B lymphocytes. These B-1 cells are mainly located in the pleural cavity or mucosal compartment. The existence of H. pylori urease-specific immunoglobulin A (IgA)-producing B cells in the mucosal compartment and of their specific IgM in the sera of acutely infected volunteers suggests the possibility that urease stimulates mucosal innate immune responses. Here, we show for the first time that purified H. pylori urease predominantly stimulates the B-1-cell population rather than B-2 cells, which produce antigen-specific conventional antibodies among splenic B220(+) B cells. The fact that such stimulation of B-1 cells was not affected by the addition of polymyxin B indicates that the effect of purified H. pylori urease was not due to the contamination with bacterial lipopolysaccharide. Furthermore, the production of various B-1-cell-related autoreactive antibodies such as IgM-type rheumatoid factor, anti-single-stranded DNA antibody, and anti-phosphatidyl choline antibody was observed when the splenic B cells were stimulated with purified H. pylori urease in vitro. These findings suggest that H. pylori components, urease in particular, may be among the environmental triggers that initiate various autoimmune diseases via producing autoreactive antibodies through the activation of B-1 cells. The findings shown here offer important new insights into the pathogenesis of autoimmune disorders related to H. pylori infection.
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PMID:Implications for induction of autoimmunity via activation of B-1 cells by Helicobacter pylori urease. 1636 78

A 58-year-old man with cough and bloody sputum was admitted because of right lung tumor and thrombocytopenia. Idiopathic thrombocytopenic purpura (ITP) was diagnosed. For treatment of ITP, he was treated with platelet transfusions, intravenous gamma-globulin and oral prednisolone. However, the platelet count did not completely improved. Since a relationship between ITP and Helicobacter pylori (HP) infection has been reported, and result of urease test was positive, the patient was treated by HP eradication therapy. After the eradication therapy, the platelet count improved to the normal range. The diagnosis of squamous cell carcinoma of the lung was confirmed by a cervical lymph node biopsy. As a result of improvement in platelet count, we were able to perform the chemotherapy of lung cancer.
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PMID:[A case of lung cancer with idiopathic thrombocytopenic purpura effectively treated for Helicobacter pylori]. 1818 49

Helicobacter pylori (H. pylori) infection causes gastro-duodenal diseases and a wide variety of non gastrointestinal tract conditions, such as idiopathic thrombocytopenic purpura (ITP). Many reports have provided robust evidence for understanding the pathogenesis of H. pylori. However, its cell division process is little known. H. pylori exhibits marked genetic diversity to survive under various stress conditions, leading to the emergence of a variety of clones with novel characteristics. In this report, we briefly summarize our results. H. pylori urease is essential to live in a low-pH environment. Bacterial motility and urea taxisis are also important features for persistent infection. The urease is controlled in response to the pH via post translational regulation. Genetic rearrangement occurs during persistent infection of an individual's stomach, which results in the appearance of a variety of new strains with novel characteristics. The cdrA (cell division-related gene A)--dysfunctional strain had acquired such novel characteristics: increased viability, long-term survival, and tolerance to antibiotics. Furthermore, colonization by a cdrA-dysfunctional strain results in decreased IL-8 production and, hence, attenuates the host's immunity to cause persistent infection. Among the factors involved in the bacterium-host interaction and pathogenesis, we describe the H. pylori CagA, BabA, SabA, and SOD. We discovered two H. pylori phages, including a new type of spherical phage, which cannot be classified into any existing virus category. The phages probably contribute to the evolution and pathogenesis of H. pylori. Eradication therapy covered by health insurance was approved for H. pylori-associated ITP. We reported an extra mechanism, the immunocomplex model (platelets, bacterial molecules, and anti H. pylori antibodies), in the development of H. pylori associated ITP. On the other hand, increased cases of unsuccessful eradication therapy are due to the increased occurrence of drug-resistant H. pylori. Non-antibiotic substances with anti-H. pylori activity are attracting much attention.
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PMID:[Molecular-pathological analysis of Helicobacter pylori-associated disorders and clinical laboratory testing]. 2505 58