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:3.5.1.5 (urease)
7,257 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The polymerase chain reaction was used for the detection of Helicobacter pylori from subgingival plaque in 336 periodontitis patients. A pair of primers derived from the H. pylori urease gene A served to amplify a targeted 411-bp fragment of genomic DNA. This technique permitted the detection of as few as 60 H. pylori cells. Paper point samples from 3 deep periodontal pockets per patient were immersed in 1 ml of phosphate-buffered saline or distilled water, DNA was solubilized by detergent/protease method, 3.7 microliters or 37 microliters of lysate supernatant was used as template, and the amplification product was analyzed in 1% agarose gel containing ethidium bromide. Each experiment included purified DNA and cell lysate of H. pylori as positive controls. The presence of bacteria in the sample was verified by a primer pair common to prokaryote 16S rRNA. The present study did not reveal the specific polymerase chain reaction amplification product characteristic of H. pylori. We conclude that periodontal pockets do not constitute a natural reservoir for H. pylori.
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PMID:Absence of Helicobacter pylori in subgingival samples determined by polymerase chain reaction. 780 77

One hundred and two consecutive patients undergoing upper gastrointestinal endoscopy were tested for H. pylori by a rapid urease test, using antral biopsy specimens. There were 60 men (mean age 54 yrs) and 42 women (mean age 49 yrs). Fifty-six patients (55%) were positive for H. pylori. Of male patients, 36 (60%) and of female patients, 20 (48%) tested positive. Sixty-eight per cent of patients with antral gastritis, 65% with duodenal ulcer and 60% with gastric ulcer had H. pylori. Thirty-nine patients (70%) positive for H. pylori were from major urban areas, and 17 (30%) were from rural areas of Jamaica. In patients without H. pylori, 61% and 39% were from urban and rural areas, respectively. Forty-four patients (79%) with H. pylori and 40 (87%) without H. pylori had piped water in their homes. Ninety-three per cent of all patients had electricity and 88% had refrigeration. There was no difference between patients positive or negative for H. pylori with regard to the use of alcohol, marijuana or tobacco. There was also no difference between both groups in exposure to domestic animals in the home environment. H. pylori is associated with antral gastritis and peptic ulcer disease in Jamaican patients. There are no specific environmental or social factors that seem to predispose to infection.
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PMID:Helicobacter pylori in patients undergoing upper endoscopy in Jamaica. 781 42

Sixty-six fungal species in addition to two species varieties belonging to 31 genera were isolated during the current study from water closet (WC) sewage samples (39 species and two varieties in 20 genera) and WC air (53 species and two varieties in 25 genera). There were more fungi in the WC air than in sewage. The most prevalent fungi in WC sewage and air were members of the genera Aspergillus, Cladosporium and Penicillium. Acremonium, Alternaria, Emericella, Mycosphaerella and Pleospora were dominant only in WC air. Some species of these genera are considered to be true or opportunistic pathogens. The pollution level due to the bacterial flora either in the air or in the sewage of WCs was relatively higher than that of the fungal flora. Testing the capability to produce urease, nearly all fungal isolates (65 out of 67) and bacteria tested (35 out of 36) proved to be good urease producers.
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PMID:Mycoflora inhabiting water closet environments. 793 94

Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer disease. Further definition is needed of the factors that determine whether infected individuals remain asymptomatic, or ultimately develop ulceration of the mucosa or transformation to malignancy. To explore the possibility that host response to H. pylori may play a role in the outcome of this infection, we have examined humoral and cellular recognition of several H. pylori proteins by seropositive and seronegative persons. A complex mixture of water-extractable cell proteins, which did not include lipopolysaccharide (LPS), was recognized by serum antibodies only in seropositive or infected individuals. IgG from seropositive subjects also bound to urease and to a heat shock protein (hsp)60 that is homologous to the 65-kD mycobacterial heat shock protein, while sera from uninfected individuals were negative. Although antibody responses to these antigens were restricted to seropositive subjects, T cell recognition of the same proteins was found in both seropositive and seronegative subjects. The water extract of H. pylori stimulated peripheral blood mononuclear cells (PBMC) from all subjects, while purified proteins activated lymphocytes of only some seropositive and seronegative subjects. PBMC that were activated by the H. pylori hsp60 did not respond to the autologous human p60 heat shock protein. These results demonstrate that, in contrast to antibody responses, T cell recognition of H. pylori proteins may occur in non-infected persons. In addition, the data suggest that in these subjects, peripheral lymphocytes that are activated by bacterial heat shock proteins do not mediate tissue damage by recognition of human heat shock homologues.
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PMID:Humoral and cellular immune recognition of Helicobacter pylori proteins are not concordant. 803 9

In a prospective case controlled study, we evaluated the adverse effects of long-term fluoride ingestion on the gastrointestinal tract. Ten patients with otosclerosis who were receiving sodium fluoride 30 mg/day for a period of 3-12 months, and 10 age- and sex-matched healthy volunteers were included. They were all evaluated clinically and subjected to a real time ultrasound examination, upper gastrointestinal endoscopy, and biopsies from the gastric antrum and duodenum. The biopsies were subjected to a rapid urease test as well as light and electron microscopic examinations. Ionic fluoride was estimated in the serum, urine, and drinking water using an ION 85 Ion Analyzer. Seven subjects (70%) ingesting fluoride had abdominal pain, vomiting, and nausea. Petechiae, erosions, and erythema were seen on endoscopy in all the subjects, but not in the controls. Histological examination of the gastric antral biopsy showed chronic atrophic gastritis in all the subjects but in only one (10%) healthy volunteer. Scanning electron microscopic examination showed "cracked-clay" appearance, scanty microvilli, surface abrasions, and desquamated epithelium in the subjects ingesting fluoride, but not in the controls. We conclude that long-term fluoride ingestion is associated with a high incidence of dyspeptic symptoms as well as histological and electron microscopic abnormalities.
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PMID:Toxic effects of chronic fluoride ingestion on the upper gastrointestinal tract. 803 13

Texel wethers (68 +/- 2.5 kg BW) fitted with catheters in the ruminal veins and a mesenteric artery, blood flow probes on ruminal arteries, and a ruminal cannula were fed 500 g of orchardgrass hay every 12 h. During the last third of the feeding cycle, intraruminal injections were performed to evaluate the effect of urease activity, osmolality, and concentrations of NH3, butyrate, and CO2 in the rumen on urea and NH3 fluxes across the rumen wall. At pH 6.7, NH3 absorption increased with NH3 and butyrate concentrations in the rumen, and to a lesser extent with CO2 concentration. The increase in ruminal blood flow associated with CO2 and butyrate increase was always greater than the increase in NH3 absorption. Increasing ruminal osmolality slightly decreased NH3 absorption. Ruminal NH3 concentration and ruminal blood flow seemed to be the main determinant of NH3 absorption. Decreasing urease activity in the rumen decreased urea net transfer. The net transfer of urea to the rumen was stimulated by CO2. High concentrations of NH3 (330 mg of N/L) and butyrate (25 mM) in the rumen decreased urea net uptake, whereas osmolality (up to 420 mOsmol/L) did not affect it. Modifications in ruminal blood flow or water net movement across the ruminal wall did not seem to account for the effect of CO2, NH3, and butyrate on urea net uptake.
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PMID:Net transfer of urea and ammonia across the ruminal wall of sheep. 822 81

The urease of Helicobacter pylori is an important antigen and appears critical for colonization and virulence. Several studies have indicated a superficial localization for the H. pylori urease, and the purpose of this study was to determine the effects of cations on the release and stability of urease activity from H. pylori cells. Incubation of partially purified H. pylori urease in water containing 1, 5, or 10 mM Ca2+, Mg2+, K+, Na+, EDTA, or EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] had little effect on activity. In contrast, 1 mM Fe3+, Cu2+, Co2+, or Zn2+ substantially (> 80%) inhibited activity, and 10 mM Fe2+, Mn2+, and Ni2+ inhibited about 30% of the activity. Addition of Ca2+ or Mg2+ markedly decreased extraction of urease from intact H. pylori cells by water, but 1 mM Na+, K+, EGTA, or EDTA each had minimal effects on release, suggesting that divalent cations have a role in attachment of urease to H. pylori cells. The stability of enzymatic activity at 4 degrees C was enhanced by addition of glycerol or 2-mercaptoethanol; however, even after loss of activity, full antigenicity for human serum was retained.
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PMID:Effects of cations on Helicobacter pylori urease activity, release, and stability. 826 43

The in vitro effect of urea and hydrolysis of urea by urease on mucus H+ permeability is reported here. The effective DHCl values indicate a strong pH dependence for H+ diffusion in both water and mucus layers, with no apparent trend at concentrations between 1 and 50 mM urea. However, the estimated DHCl at near-neutral and alkaline pH are 4- to 10-fold lower through mucus than through aqueous films. Moreover, the pKa values of HCO3- and NH3 (generated by urease action on urea) had a profound effect on measured DHCl. These in vitro studies suggest that a high local concentration of NH3 and HCO3- within the mucus layer, generated by the action of Helicobacter pylori urease on endogenous intragastric urea, could greatly accelerate proton flux to the surface epithelium by operation of a buffer shuttle. This results in enhanced H+ permeability, particularly at pKa values of HCO3- and NH3, and in extreme circumstances it may result in gastric ulcer formation.
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PMID:An in vitro study of enhanced H+ diffusion by urease action on urea. Implications for Helicobacter pylori-associated peptic ulceration. 826 22

We analyzed 11 H. pylori isolates from humans using the artificial chromogenic substrate paranitrophenylphosphorylcholine to detect phospholipase C (PLC) activity. The range of PLC in sonicates was 8.8-92.3 (Mean 56.9 +/- 6.5) nmol of substrate hydrolysed min-1 mg-1 protein; the amount of activity was not associated with urease or cytotoxin levels. Addition of sorbitol or glycerol enhanced PLC activity of H. pylori sonicate and purified PLC from C. perfringens (PLC1) but not purified PLC from B. cereus (PLC3). H. pylori sonicates had little acid phosphatase and no detectable alkaline phosphatase activity, and H. pylori PLC showed markedly different biochemical characteristics from either phosphatase. In total, these studies indicate that activity measured in H. pylori sonicate by PLC assay is due to PLC and not phosphatase activity. The temperature optimum for PLC activity of H. pylori sonicate was 56 degrees C and for PLC 1 was 65 degrees C. For H. pylori PLC and PLC1, optimal activity occurred at pH 8. Despite multiple similarities between H. pylori PLC and PLC1, known PLC inhibitors show different interactions with each enzyme. Although PLC activity is present in many subcellular constituents of H. pylori, including culture supernatants and water extracts, highest specific activity is associated with a membrane-enriched fraction.
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PMID:Identification and characterization of Helicobacter pylori phospholipase C activity. 828 Sep 31

To evaluate the sensitivity of a polymerase chain reaction (PCR) assay using nested primers in detecting Helicobacter pylori, gastric tissue biopsy specimens were collected on endoscopy from 17 patients with a duodenal ulcer. DNA was extracted by phenol/chloroform treatment or boiling in water, and then subjected to a nested PCR using two primer pairs from the urease gene of Helicobacter pylori. Fourteen of the 17 patients were positive for Helicobacter pylori using DNA samples extracted by either method. The PCR results correlated well with the results of an enzyme immunoassay to detect IgG antibody. However, there were two culture negative patients. The three PCR negative patients were both culture negative and serologically negative. DNA from 9 of the 14 patients was randomly selected and subjected to semiquantification by serial dilutions, and then PCR. The results showed that phenol/chloroform extraction yielded 10-1000 times more DNA than the boiling method. It is concluded that the PCR assay is a rapid and sensitive method for detecting Helicobacter pylori, and that phenol/chloroform extraction is superior to simple boiling in obtaining DNA samples for PCR.
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PMID:Detection of Helicobacter pylori in gastric biopsy tissue by polymerase chain reaction. 835 5


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