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)

A visual, enzyme-linked immunosorbent assay using urease (ELISA-U) as the enzyme marker was adapted for rapid detection of antibody against Plasmodium falciparum. Flat-bottom, 96-well microtiter plates were coated with P. falciparum soluble antigen obtained by saponin and NP-40 treatment of parasite cultures. Antibody was detected by successive incubations with test sera, urease-conjugated rabbit-human antibody, and urease substrate. Reactive sera developed a definite and easily visualized purple color. Sera from patients with single infections of P. vivax or P. ovale were unreactive. No cross-reactivity was noted with sera from patients with rheumatoid arthritis, filariasis, amebiasis, schistosomiasis, dengue, scrub typhus, leptospirosis, or toxoplasmosis. The procedure can be performed at room temperature and completed within 1 hr. The sensitivity of the assay is comparable to that of the indirect fluorescent antibody test at all but the lowest dilutions tested.
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PMID:The ELISA-U: an enzyme-linked immunosorbent assay using urease as the enzyme marker for rapid detection of Plasmodium falciparum antibody in human serum. 305 27

Non-steroidal anti-inflammatory drugs (NSAIDs) and Helicobacter (H pylori) are both associated with an increased risk of peptic ulceration and gastropathy. It is not known, however, if there is an interaction between these two agents, and thus whether or not screening for H pylori before NSAID treatment is of value. The aim of this study was to find out if H pylori potentiates the damaging effects of NSAIDs. Fifty two patients with rheumatoid arthritis requiring longterm NSAID treatment were studied. Dyspeptic symptoms were assessed according to a standardised questionnaire. Gastroscopy was performed after a one week washout period during which NSAIDs were discontinued. Gastric and duodenal mucosal damage was graded endoscopically. H pylori was identified by biopsy urease test and by histological tests. Investigations were repeated after one month's treatment with an NSAID. Patients with H pylori infection (n = 26) had a higher dyspeptic symptom score (p < 0.05). One patient with duodenal ulcer (H pylori +ve) and two with endoscopic gastritis (both H pylori +ve) were excluded from further study. Forty two subjects completed the study. After treatment there was a rise in the gastric damage score both in the H pylori +ve (p = 0.06) and the H pylori -ve (p < 0.005) groups. There was no difference in the extent of increase in grade or the final grade at the end of the treatment period between the H pylori +ve and -ve patients. It is concluded that H pylori infection is associated with increased dyspeptic symptoms in patients receiving NSAIDs but that it does not potentiate NSAID gastropathy.
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PMID:Prevalence of Helicobacter pylori infection and its effect on symptoms and non-steroidal anti-inflammatory drug induced gastrointestinal damage in patients with rheumatoid arthritis. 828 54

Cross-reactivity or molecular mimicry may be one of the underlying mechanisms involved in the etiopathogenesis of rheumatoid arthritis (RA). Antiserum against the RA susceptibility sequence EQKRAA was shown to bind to a similar peptide ESRRAL present in the hemolysin of the gram-negative bacterium Proteus mirabilis, and an anti-ESRRAL serum reacted with EQKRAA. There was no reactivity with either anti-EQKRAA or anti-ESRRAL to a peptide containing the EDERAA sequence which is present in HLA-DRB1*0402, an allele not associated with RA. Furthermore, the EQKRAA and ESRRAL antisera bound to a mouse fibroblast transfectant cell line (Dap.3) expressing HLA-DRB1*0401 but not to DRB1*0402. However, peptide sequences structurally related to the RA susceptibility motif LEIEKDFTTYGEE (P. mirabilis urease), VEIRAEGNRFTY (collagen type II) and DELSPETSPYVKE (collagen type XI) did not bind significantly to cell lines expressing HLA-DRB1*0401 or HLA-DRB1*0402 compared to the control peptide YASGASGASGAS. It is suggested here that molecular mimicry between HLA alleles associated with RA and P. mirabilis may be relevant in the etiopathogenesis of the disease.
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PMID:Cross-reactivity between the rheumatoid arthritis-associated motif EQKRAA and structurally related sequences found in Proteus mirabilis. 1033 79

A 62-year-old Japanese woman with RA received an eradication therapy against Helicobacter pylori in November 1999. Eight weeks later, successful eradication was confirmed by negative results for rapid urease test, pathologic findings, and a fall in anti-H. pylori IgG antibody titer. During the course, parameters for RA activity were exacerbated: C-reactive protein 1.1-4.2 mg/dL, rheumatoid arthritis precipitation antigen 2560-5120 dils., erythrocyte sedimentation rate 52-123 mm/h, and complements CH50 50 to over 60 U/mL. Lansbury index increased from 70% to 105%. Two more weeks later, the patient noticed right shoulder pain. She also complained of bilateral gonalgia two months later, and physical examination revealed increased fluid in the knee joints. Prednisolone was required to control the disease activity. The results of this case suggested that RA patients might experience a deleterious effect on the disease activity following H. pylori eradication possibly through disruption of the established oral tolerance against stress protein such as mycobacterial heat shock protein 65.
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PMID:Exacerbation of rheumatoid arthritis following Helicobacter pylori eradication: disruption of established oral tolerance against heat shock protein? 1553 8

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 74-year-old woman presented with painful ulcerative nodules on the left forearm. She had received systemic steroid therapy for rheumatoid arthritis for several years. On physical examination, there were four hemorrhagic ulcerative nodules with a linear distribution on the left forearm (Fig. 1A). These nodules had developed over the course of 2 months, and the number of lesions had increased despite systemic antibiotic therapy. There was no sign of systemic dissemination of the disease. Biopsy of a nodule demonstrated suppurative granulomatous infiltration (Fig. 1B); the hyphae stained positive with periodic acid-Schiff (data is not shown) and Gomori-methenamine silver stains in the dermis (Fig. 1C). The biopsy specimen was cultured in Sabouraud's dextrose agar supplemented with cycloheximide with incubation at 26 degrees C. A yeast-like creamy colony grew in 1 week. The colony became yellowish gray in color and the surface folded radially after 4 weeks of incubation (Fig. 2A). Microscopic examination revealed arthroconidia and blastoconidia (Fig. 2B), and urease activity was positive. The fungus was identified as Trichosporon beigelii by yeast biochemical card (YBC, Biomerieux Vitek, Inc., Hazelwood, MO, USA). The sequences of rDNA obtained from the colony were amplified using polymerase chain reaction (PCR) primer, analyzing the sequences of the 5.8S and 28S rDNA regions for the genetic identification of the Trichosporon species. The sequences of the PCR product matched the corresponding sequences of the T. inkin strain with 99% accuracy (Fig. 2C). The patient was given oral itraconazole for 8 weeks with good clinical results.
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PMID:Trichosporon inkin subcutaneous infection in a rheumatoid arthritis patient. 1734 85

Rheumatoid arthritis is a crippling and disabling joint disease affecting over 20 million people. It occurs predominantly in women and smokers, and affects the HLA-DR1/4 individuals who carry the "shared epitope" of amino acids EQRRAA. The cause of this disease was investigated by the methods of the philosopher of science Karl Popper who suggested that scientific research should be based on bold conjectures and critical refutations. The "Popper sequences" generate new facts which then change or alter the original problem. The new facts must then be explained by any new theory. Using the "molecular mimicry" model, it was found that Proteus bacteria possess an amino acid sequence ESRRAL in haemolysin which resembles the, shared epitope, and another sequence in urease which resembles type XI collagen. Antibodies to Proteus bacteria have been found in 14 different countries. It would appear that rheumatoid arthritis is caused by an upper urinary tract infection by Proteus bacteria. Anti-Proteus therapy should be assessed in the management of this disease separately or in conjunction with existing modalities of therapy.
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PMID:Rheumatoid arthritis is caused by Proteus: the molecular mimicry theory and Karl Popper. 1948 74

Rheumatoid arthritis (RA) is a crippling joint disease affecting over 20 million people worldwide. The cause of RA is most probably linked to the triad of microbial trigger, genetic association and autoimmunity and can be explained using the philosophical method of Karl Popper or Popperian sequences. Ten "Popper sequences" have been identified which point to the urinary microbe Proteus mirabilis as the cause of RA: Popper sequence 1 establishes that HLA-DR4 lymphocytes injected into a rabbit evoke specific antibodies against Proteus bacteria. Popper sequence 2 establishes that antibodies to Proteus bacteria are present in RA patients from 14 different countries. Popper sequence 3 establishes that antibodies to Proteus bacteria in RA patients are disease specific since no such antibodies are found in other conditions. Popper sequence 4 establishes that when RA patients have high titres of antibodies to Proteus such bacteria are found in urinary cultures. Popper sequence 5 establishes that only Proteus bacteria and no other microbes evoke significantly elevated antibodies in RA patients. Popper sequence 6 establishes that the "shared epitope" EQR(K)RAA shows "molecular mimicry" with the sequence ESRRAL found in Proteus haemolysin. Popper sequence 7 establishes that Proteus urease contains a sequence IRRET which has "molecular mimicry" with LRREI found in collagen XI of hyaline cartilage. Popper sequence 8 establishes that sera obtained from RA patients have cytopathic properties against sheep red cells coated with the cross-reacting EQR(K)RAA and LRREI self-antigen peptides. Popper sequence 9 establishes that Proteus sequences in haemolysin and urease as well as the self antigens, HLA-DR1/4 and collagen XI, each contain an arginine doublet, thereby providing a substrate for peptidyl arginine deiminase (PAD) to give rise to citrulline, which is the main antigenic component of CCP, antibodies to which are found in early cases of RA. Popper sequence 10 establishes that antibodies to Proteus come not only from sequences crossreacting to self antigens but also from non-crossreacting sequences, thereby indicating that active RA patients have been exposed to infection by Proteus. The ten Popper sequences establish that RA is most probably caused by Proteus upper urinary tract infections, which can possibly be treated with anti-Proteus therapy.
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PMID:Rheumatoid arthritis, Proteus, anti-CCP antibodies and Karl Popper. 1989 6

Rheumatoid arthritis (RA) is a chronic disease with an autoimmunological background. RA is mostly characterized by systemic inflammation and injuries of synovial joints. There is a hypothesis that bacterial infections may be connected with development of the disease. It has been suggested that molecular mimicry between bacterial and human antigens may be one of possible mechanisms of RA development. One of potential antigens involved in this mechanism is urease - enzyme with high structural conservatism, occurring in pathogenic and commensal bacteria. We found that the level of antibodies against peptide mimicking urease "flap" region is significantly higher in sera from patients with rheumatoid arthritis in comparison with volunteer blood donor sera. We also observed that antibodies present in RA sera may bind not only specific peptide antigens but also peptides with a slightly different structure.
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PMID:Detection of antibodies against synthetic peptides mimicking ureases fragments in sera of rheumatoid arthritis patients. 2258 80

Urease is a virulence factor found in various pathogenic bacteria. It is essential in colonization of a host organism and in maintenance of bacterial cells in tissues. Due to its enzymatic activity, urease has a toxic effect on human cells. The presence of ureolytic activity is an important marker of a number of bacterial infections. Urease is also an immunogenic protein and is recognized by antibodies present in human sera. The presence of such antibodies is connected with progress of several long-lasting diseases, like rheumatoid arthritis, atherosclerosis or urinary tract infections. In bacterial ureases, motives with a sequence and/or structure similar to human proteins may occur. This phenomenon, known as molecular mimicry, leads to the appearance of autoantibodies, which take part in host molecules destruction. Detection of antibodies- binding motives (epitopes) in bacterial proteins is a complex process. However, organic chemistry tools, such as synthetic peptide libraries, are helpful in both, epitope mapping as well as in serologic investigations. In this review, we present a synthetic report on a molecular organization of bacterial ureases - genetic as well as structural. We characterize methods used in detecting urease and ureolytic activity, including techniques applied in disease diagnostic processes and in chemical synthesis of urease epitopes. The review also provides a summary of knowledge about a toxic effect of bacterial ureases on human body and about occurrence of anti-urease antibodies in long-lasting diseases.
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PMID:Bacterial urease and its role in long-lasting human diseases. 2330 65


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