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)

Acid urease was purified to an electrophoretically homogeneous state, and the molecular weight was estimated to be 220,000. The enzyme consisted of three kinds of subunits, designated alpha, beta and gamma, with molecular weights of 67,000, 16,800 and 8600, respectively, in a (alpha 1 beta 2 gamma 1)2 structure. The isoelectric point of the enzyme was 4.8. The nickel content was found to be 1.9 atoms of nickel per alpha 1 beta 2 gamma 1 unit. The amino acid profile was different from those of known bacterial neutral ureases. The enzyme was most active at pH 2 and around 65 degrees C. It was stable between pH 3 and 9, and below 50 degrees C. The Km for urea was 2.7 mM at pH 2. The enzyme activity was inhibited by Ag+, Hg2+, Cu2+, p-chloromercuribenzoate and acetohydroxamate. The enzyme was separated into three subunits by reverse phase HPLC. The amino terminal amino acid sequences of the subunits alpha, beta and gamma were Ser-Phe-Asp-Met-, Met-Val-Pro-Gly- and Met-Arg-Leu-Thr-, respectively.
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PMID:Purification and characterization of acid urease from Lactobacillus fermentum. 136 38

To determine whether omeprazole eradicates Helicobacter pylori infection of the gastric antrum, six adolescents and one adult with H. pylori colonization of the antrum were entered into a clinical, open trial of medical therapy. Histologic evidence of antral gastritis and three complementary methods to document H. pylori colonization of the stomach (silver stain, urease testing, and culture of antrum) were obtained before and after an 8-week course of omeprazole. In vitro susceptibility to omeprazole and restriction endonuclease analysis were performed on H. pylori isolates obtained from patients before and after omeprazole therapy. Each of the seven patients treated with omeprazole had continued active inflammation in the antrum and one or more features indicative of persisting H. pylori colonization. Minimum inhibitory concentrations and DNA fingerprints of H. pylori isolated after therapy were identical to those of the pre-treatment bacterial isolates in each of the four subjects examined. We conclude that omeprazole therapy alone did not eradicate H. pylori infection of the human antrum. Continued bacterial colonization was not related to either acquired bacterial resistance to the drug or reinfection of the stomach with a different H. pylori strain.
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PMID:Omeprazole therapy for Helicobacter pylori infection. 147 17

Gastric biopsies were obtained from 125 subjects to compare detection of Helicobacter pylori by culture, a rapid urease test and histopathologic examination using haematoxylin-eosin, Gram, Giemsa, Warthin-Starry silver and acridine orange stains. Helicobacter pylori was isolated from 39 specimens. Acridine orange and Giemsa were the most sensitive stains, detecting 85% and 79% of positive specimens respectively. All stains showed high specificity (97-100%). The sensitivity and specificity of the rapid urease test was 62% and 100% respectively. These stains or the rapid urease test may be useful for rapid detection of Helicobacter pylori in gastric biopsies.
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PMID:Comparison of four stains and a urease test for rapid detection of Helicobacter pylori in gastric biopsies. 169 73

Catheter-associated urinary tract infections (UTIc) remain the most common nosocomial infection. Although usually benign, UTIc cause bacteremia in 2-4% of patients and have been associated with a case fatality rate three times as high as nonbacteriuric patients. Risk factors for UTIc identified in multivariate analyses include increasing duration of use, female sex, absence of systemic antibiotics, and disconnection of the catheter-collecting tube junction. Recent studies suggest that most episodes of low colony count bacteriuria (10(2)-10(4) cfu/ml) rapidly progress to high (greater than or equal to 10(5)/ml) colony counts within 24-48 hours. In persons with long-term catheterization, bacteriuria inevitably develops and the infecting strains change frequently. In this setting, Proteus and Morganella species produce catheter encrustations and persistent bacteriuria. Routes of bacterial entry have been well defined and differ by gender, with the periurethral route predominating in women and the intraluminal route in men. Growth of bacteria in biofilms on the inner surface of catheters promotes encrustation and may protect bacteria from antimicrobial agents. Bacterial virulence factors have not been well characterized in UTIc, but fimbrial adhesins have been associated with bacterial persistence in the catheterized urinary tract, and urease production has been associated with stone formation and catheter encrustation. Recent efforts to prevent UTIc have focused mainly on preventing bacterial entry to the urinary tract or eradicating bacteriuria after its onset and have been largely unsuccessful. Systemic antimicrobials, sealed tubing and catheter junctions, silver ion-coated catheters, and antiseptics in the collecting bag have all been efficacious in one or more controlled trials. Failure to stratify patients by major risk factors, especially gender, antimicrobial exposure, and catheter duration, makes interpretation of many trials difficult. Further research in the areas of innovative catheter system design, bacterial-host epithelial cell interaction, and targeted antimicrobial prophylaxis seem the most likely approaches to controlling UTIc in the future.
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PMID:Catheter-associated urinary tract infections: epidemiology, pathogenesis, and prevention. 192 94

Helicobacter pylori (formerly Campylobacter pylori) has been recently described as a gastritis-associated bacterium. We examined endoscopic biopsies of 100 patients with dyspepsia and found H. pylori in the gastric antrum of 34 (34%) by either culture, urease tests and/or histology. Thirty-one out of 41 patients (75.6%) confirmed to have chronic active gastritis histologically had H. pylori in their gastric antrum compared to 3 out of 59 patients (5.1%) with dyspepsia but normal histology (p less than 0.01). Histological examination, using gram stain and the Warthin-Starry Silver stain, detected 29 of the 34 positive cases (85.3%); urease test, 26 cases (76.5%) and culture, 22 cases (64.7%). A combination of histological examination and urease test increased the detection rate to 97.1%. Therefore we felt that for the detection of H. pylori in endoscopic biopsies, culture, which is time consuming and expensive, is not necessary in routine diagnosis as it did not improve the diagnostic rate over a combination of histology and urease test. A comparative study on three media (blood agar, chocolate agar and Skirrow's agar) used in the isolation of the organism showed that non-selective blood agar and chocolate agar were superior to Skirrow's agar. The strains isolated appeared to be homogeneous in their morphological and biochemical characteristics.
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PMID:Detection of Helicobacter pylori from endoscopic biopsies and the biochemical characteristics of these isolates. 210 69

Fifty unselected patients undergoing routine esophagogastroduodenoscopy were evaluated for infection with Campylobacter pyloris (CP). Antral specimens were cultured, and biopsies from the antrum and the body of the stomach were examined histologically. Specimens of antral brushings were analyzed with Gram stain, and urease testing was performed on gastric aspirates, antral brushings, and antral biopsy homogenates. Twenty-seven (54%) patients were CP-positive by silver stain and/or culture of mucosal biopsies. The simplest and fastest diagnostic methods was Gram stain of antral brushing, which was 93% sensitive and 100% specific. CP-negative patients were more likely to have normal histology in antrum and body tissues, while CP-positive patients usually exhibited superficial or chronic gastritis (p less than 0.01). Using ELISA technique, 67% of all patients and 89% of CP-positive patients had serum antibodies against sonicated CP organisms. We conclude that evidence of gastric CP infection is common, is associated with inflammatory changes of the gastric mucosa, is suggested by finding antibodies to CP in serum, and can be accurately and rapidly diagnosed by staining of endoscopically derived cytology and biopsy specimens.
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PMID:Evaluation of methods for identification of Campylobacter pyloris infection. 229 95

A selective method for staining urease activity bands in nondenaturing polyacrylamide gels is described. It is based on the deposition of silver at the urease bands after incubation of gels in the presence of urea and photographic developers. Its highly sensitivity (up to 0.015 enzyme units, corresponding to 5 ng of purified urease) is based on both the silver deposition enhancement methodology and the developers used. The selectivity of the procedure is based on the local pH increase catalytically produced by the enzyme in the presence of urea. The densitometric scan of the enzyme bands gives a linear response at least in the range 0.015-0.300 urease units. This selective staining method is about 2.5 times more sensitive than the standard silver staining of proteins, in terms of detectable urease amount.
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PMID:Selective silver staining of urease activity in polyacrylamide gels. 247 57

Campylobacter pylori infection was sought in 382 consecutive patients referred for upper gastrointestinal endoscopy. Five antral biopsy specimens were taken from each patient: one was inserted into a CLO-test to detect the urease activity of C pylori, two were sent for histological analysis where multiple sections were stained by the Warthin-Starry silver method, and two were sent for microbiological evaluation by Gram stain and culture. A patient was deemed to be infected when C pylori was cultured or seen in either the histological sections or the Gram stain of the biopsy smear. One hundred and seventy four (46%) patients were infected. Culture, Gram stain, histological examination and the CLO-test showed sensitivities of 92%, 87%, 93% and 90%, respectively. In 27 (15%) infected patients an uneven distribution of C pylori was seen between samples in the biopsy pair sent for histology. Examination of multiple sections stained with Warthin-Starry silver was more sensitive at detecting infection (93%) than examination of multiple sections from only one biopsy specimen (84%). Fifty seven of 80 patients, biopsied a median seven days (range 5 to 55) after completing colloidal bismuth subcitrate treatment, were still infected with C pylori. There was no decrease in the sensitivities of the above tests to detect infection after treatment. It is concluded that at least two antral biopsy specimens should be examined when attempting to diagnose C pylori infection by histological methods.
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PMID:Campylobacter pylori infection in biopsy specimens of gastric antrum: laboratory diagnosis and estimation of sampling error. 247 79

The occurrence of Campylobacter pylori (CP) was studied in 180 patients referred for endoscopy. The bacterium was detected by culture, histology (Warthin-Starry staining) and urease test of antral biopsy samples. Patient groups were formed according to endoscopic diagnoses, clinical symptoms and antral mucosal histology. 50 CP positive patients with chronic antral gastritis were treated by bismuth subsalicylate (2,4 g/day) for 3 weeks. Positivity by culture and/or silver-stained histology proved to be the most reliable way for detecting CP. CP was proved in about 30% in patients with normal gastroduodenum (13/42) or with stump gastritis (4/15), in 75% with endoscopic antral gastritis (51/68) and in 89% with duodenal ulcer (49/55). A close relationship between CP and histological chronic antral gastritis could be demonstrated. No causal link between CP positive chronic active antral gastritis and non-ulcer dyspepsia could be verified. The decrease in histological activity of chronic gastritis and in dyspeptic complaints after bismuth salt therapy was found to be independent of CP elimination. The results of control investigations following a therapy-free interval of 7-10 days speak in favour of CP recolonialisation within a relativelly short period. It can be concluded that, despite the undeniable relationship between CP and chronic antral gastritis and duodenal ulcer, further studies are necessary to clarify the clinical relevance of the CP infection.
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PMID:[Has Campylobacter pylori infection any clinical relevance? Methodologic, epidemiologic and clinical studies]. 268 46

The high endogenous urease activity of Campylobacter pylori was exploited in a non-invasive test for the presence of this organism in the stomach. When 13C-urea was administered orally after a test meal, urea-derived 13CO2 appeared in the respiratory CO2 of infected individuals at a constant rate for greater than 100 min. The test was validated in 26 individuals who underwent both the 13C-urea breath test and endoscopic biopsy of the antral mucosa for culture and histological examination. Each positive breath test proved to be correlated with a positive culture or Warthin-Starry silver stain of a mucosal biopsy specimen, or both.
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PMID:Campylobacter pylori detected noninvasively by the 13C-urea breath test. 288 91


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