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)

We found spiral bacteria (non-Helicobacter pylori, SB) in gastric biopsies of 5 patients corresponding to an incidence of 0.3%. The bacteria were found on the surface of the gastric mucosa and in part tightly packed within the crypts. Contrary to Helicobacter pylori, most of them had no direct contact to the surface and crypt epithelium. They are distinctly coiled, 3.6-5.5 microns in length and on average 0.5 microns thick. Ultrastructural studies revealed sheathed flagella at each pole. In one case the bacteria displayed periplasmic fibrils in pairs as also described in cultures of SB from cats' stomachs. In all 5 cases there was histological evidence of inflammation of the gastric mucosa, i.e. one acute diffuse gastritis, one case of granulomatous and three of slight to medium grade chronic gastritis. Biopsies of 2 patients showed a positive urease reaction in the CLO test. Morphologically very similar SB occur as commensals in the stomachs of various animals, in particular dogs and cats. We investigated the stomachs of four dogs and four cats and found all to be infested with SB. The bacteria were found not only on the surface of the mucosa and in crypts, but within the glands of the corpus and antrum and often also within parietal (oxyntic) cells. Yet despite bacterial colonization there was no evidence of gastritis in dogs. However, all of the cats' stomachs showed slight to medium grade chronic gastritis. Cultivation of SB has not been successful so far, with the exception of cats' stomachs. Since the germs have been defined only morphologically, the question as to how close the relationship is among SB of various origins must for the time being remain unanswered. Furthermore, species-specific pathogenicity and the possibility of contagion from animal to man has not yet been clarified.
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PMID:[Gastritis associated with Gastrospirillum hominis--a zoonosis?]. 201 19

A population of non ulcer dyspepsia outpatients with a normal gastroscopy was assessed. Clinical complaints, the type of the gastritis, its activity and bacterial density were evaluated. Helicobacter pylori (HP) was sought by histology, urease test and culture, on 3 distinct locations. HP was found in 62 p. cent of the patients, always in association with gastritis. Urease test and histology had the same sensitivity in the detection of HP. A randomized double blind study with amoxicillin vs placebo was carried out in 23 patients. At the end of 4 week treatment, a gastroscopy with biopsies was performed. The amoxicillin treated patients were significantly cured or improved. HP was undetectable or the bacterial density was decreased in this group. After amoxicillin, urease test was more sensitive than histology. HP might be involved in the pathophysiology of non ulcer dyspepsia in patients where HP was found.
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PMID:[Dyspepsia and Helicobacter (Campylobacter) pylori. Results of a randomized therapeutic trial using amoxicillin versus placebos]. 202 80

Helicobacter mustelae has been cultured from the stomachs of ferrets with chronic gastritis; the lesions in the stomach have many of the same histological features seen in H. pylori gastritis in humans. To determine whether H. mustelae-negative ferrets with normal gastric mucosa were susceptible to colonization and whether gastritis developed after infection, four H. mustelae-negative ferrets treated with cimetidine were inoculated orally on two successive days with 3 ml (1.5 x 10(8) CFU) of H. mustelae; eight age-matched H. mustelae-negative ferrets served as controls. All four ferrets became colonized; H. mustelae persisted through week 24 of the study, as determined by positive gastric culture, tissue urease, and Warthin-Starry staining of gastric tissue. Superficial gastritis developed in the oxyntic gastric mucosa, and a full-thickness gastritis, composed primarily of lymphocytes and plasma cells plus small numbers of neutrophils and eosinophils, was present in the antrum. The inflammation was accompanied by an elevation of immunoglobulin G antibody to H. mustelae. At 4 weeks post-inoculation, the four infected (experimental) ferrets developed an elevated gastric pH (4.0 to 5.2) for 2 weeks. The eight control ferrets did not have gastritis; H. mustelae could not be demonstrated in gastric tissue via culture, nor was there an immune response to the bacteria. In ferrets, H. mustelae readily colonizes the stomach and produces a gastritis, a significant immune response, and, like H. pylori infection in humans, a transient elevated gastric pH after Helicobacter infection.
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PMID:Helicobacter mustelae-induced gastritis and elevated gastric pH in the ferret (Mustela putorius furo). 203 49

The authors evaluated the use of direct Gram-stained smears, 1- and 24-hour urease broth tests, histologic examination, and culture to detect Helicobacter pylori in 100 gastric biopsy specimens from 97 patients with epigastric symptoms. Twenty-six patients had positive cultures and 27 had H. pylori identifiable in hematoxylin and eosin-stained sections. The gastric biopsy specimens from the 29 patients with culture and/or histologic findings positive for H. pylori showed active gastritis in 27 cases (93%), compared with 26 cases (37%) without H. pylori (P less than 0.0001). Chronic gastritis was present in 25 cases (86%) with H. pylori and 40 cases (56%) without H. pylori (P less than 0.01). Twenty patients had positive Gram-stained smears. Fifteen patients had positive 1-hour urease tests, and 3 had delayed positive 24-hour urease tests. There were no false-positive Gram's stain results, three false-positive 24-hour urease tests, two false-negative histologic results, and three false-negative cultures (one inadvertently incubated anaerobically). The sensitivities of the methods were as follows: 62% for the 24-hour urease test, 69% for direct Gram's stain, 90% for culture, and 93% for histologic examination. The authors conclude that the urease test used in this study has low sensitivity and limited specificity; that the direct Gram-stained smear is a useful, highly specific, rapid screening test; and that the lengthier methods of culture and histologic examination have comparably high sensitivity for the definitive diagnosis of H. pylori gastritis.
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PMID:Evaluation of diagnostic methods for Helicobacter pylori gastritis. 204 84

Gastric urease was studied isotopically in 230 patients with biopsy-proven normal mucosa or chronic gastritis, including 59 patients with ulcer disease. Carbon-14-urea was given in 25 ml of water without substrate carrier or nutrient-dense meal, and breath samples were collected over a 60-min period. The amount of 14CO2 excreted at 10 min was independent of the rate of gastric emptying and was not quantitatively influenced by the buccal urease activity. The 10-min 14CO2 values discriminated well between Helicobacter pylori positive and negative patients (94% sensitivity, 89% specificity) and correlated with the number of organisms assessed by histology. The test was a good predictor of chronic gastritis (95% sensitivity and 96% specificity), and a quantitative relationship was observed between 14CO2 values and the severity and activity of the gastritis. In H. pylori positive patients, breath 14CO2 was found to be similar in patients with and without ulcer disease, suggesting that the number of bacteria is not a determining factor for the onset of ulceration.
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PMID:Quantification of Helicobacter pylori infection in gastritis and ulcer disease using a simple and rapid carbon-14-urea breath test. 204 33

A mutant strain of Helicobacter pylori with weak urease activity was created by using N-methyl-N'-nitro-N-nitrosoguanidine. The urease activity of the mutant (0.036 +/- 0.009 nmol of urea per micrograms of bacterial protein per min) was 0.4% of that of the parental strain (8.20 +/- 2.30 nmol of urea per micrograms of bacterial protein per min). The mutant was otherwise indistinguishable from the parental strain. Both demonstrated prominent catalase and oxidase activities, and both produced vacuolating cytotoxin. Restriction endonuclease and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns and ultrastructure were identical for the two strains. The mutant was fully motile, as evaluated by spreading in soft agar and by direct microscopic examination. Growth rate and colony size and morphology were identical for the mutant and parental strains. Seventeen gnotobiotic piglets were challenged with either the mutant or the parental strain and sacrificed 3 or 21 days after challenge. Gastric tissue was examined histologically and cultured for H. pylori. Of seven piglets challenged with the parental strain, all became infected. H. pylori was not recovered from any of 10 piglets challenged with the urease-negative strain. Lymphofollicular gastritis was present in all seven piglets challenged with the parental strain but in none of the piglets challenged with the urease-negative strain. These results suggest that prominent urease activity is essential for colonization by H. pylori.
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PMID:Essential role of urease in pathogenesis of gastritis induced by Helicobacter pylori in gnotobiotic piglets. 205 Apr 11

The presence of Helicobacter pylori and the gastric mucosa histology were investigated in 15 children and 15 adults with duodenal ulcer. The microorganism was isolated from antral and oxyntic mucosa in 100% of patients, both adults and children. The results of Gram stain and preformed urease test were compared with those of culture and there was no difference in sensitivity among the tests. Antral chronic gastritis was observed in all patients. However, children presented oxyntic gastritis more frequently than adults. It was also observed that the endoscopic aspects were different in the two groups of patients. The results here observed strongly support the idea that, as well as in adults, H. pylori is the causative agent of the gastritis seen in children with duodenal ulceration. On the other hand, the histological findings of oxyntic mucosa of children with duodenal ulcer were different from those of adults.
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PMID:Differences in distribution and severity of Helicobacter pylori gastritis in children and adults with duodenal ulcer disease. 205 Dec 69

Helicobacter pylori seeks gastric mucosa, whether found in the stomach, duodenum, or Barrett's esophagus. Definitive diagnosis can be secured by appropriate stains of mucosal biopsies and culture, but the rapid urease test, breath isotope studies, and serologic testing are also useful. The frequency of colonization increases with advancing age, but infection occurs earlier in underdeveloped countries. Although the reservoir is uncertain, water or food transmission seems likely. There is sufficient evidence to assign an etiologic role to the bacteria in the causation of type B antral gastritis. H. pylori is found in areas of gastric metaplasia within the duodenum and is associated with duodenitis. Although acute infection leads to hypochlorhydria, chronic colonization has little effect on acid secretion. Studies have thus far failed to establish a convincing relationship between H. pylori and nonulcer dyspepsia, although the bacteria may play a role in selected patients. H. pylori is found in association with most idiopathic gastric and duodenal ulcers, but it is unclear as to whether the bacteria plays a causative or permissive role. The organism has a predilection for intercellular spaces and the mucous layer, thus affording relative isolation from luminally active antibiotics. Monotherapy with bismuth preparations transiently eliminates the bacteria, but recolonization is rapid, probably due to regrowth of sequestered organisms. A combination of metronidazole, bismuth, and tetracycline (or amoxicillin) affords the best eradication rate, but the potential side effects of this program should be considered. The present therapy of duodenal ulcer disease is effective and without significant risk. Treatment of H. pylori should be reserved for those patients who relapse on adequate maintenance therapy. If a safe and effective antibiotic becomes available, more frequent testing and earlier treatment intervention may become more attractive. H. pylori is probably an "innocent bystander" for most patients, but the bacteria may sufficiently impair the defenses of the antral and duodenal mucosa to facilitate the development and relapse of ulcer disease in subsets of patients.
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PMID:Helicobacter pylori: aggressor or innocent bystander? 207 88

In 862 unselected gastroscopies we could confirm the high percentage of campylobacter pylori infection in the antral gastric mucosa strongly associated with chronic superficial gastritis and active inflammatory signs. Significant correlation with age concerned the normal findings only. In patients with duodenal ulcers we found in 91% gastritis and in 88% campylobacter pylori in antral mucosa. A small group with duodenal ulcers was campylobacter pylori-negative as well as without gastritis signs. Comparing the antrum and corpus gastric mucosa (250 pat.) the antral mucosa was representative for the whole stomach in view of gastritis and campylobacter pylori test, sufficiently for practical use. Between the test methods (culture, urease, microscopy) we favoured the microscopic test.
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PMID:[Detection of Campylobacter pylori in gastric mucosa--relation to gastroscopy findings and degree of gastritis]. 209 69

Helicobacter pylori are commonly found colonizing the gastric mucosa of different populations. Its presence may be important in the pathogenesis of gastritis and peptic ulcer disease. The detection rates vary widely depending upon the diagnostic methods applied. In this study, multiple gastric biopsies were taken from the fundal and antral mucosa of 25 patients during endoscopy. In one patient, the procedure was repeated about two months after the initial biopsy. A total of 52 sets of specimens were obtained. One sample from each site was used to make imprint smear and tissue section. The other sample was used for microbiological culture and rapid urease test. An association between histological confirmed chronic gastritis (both active and inactive) and the morphological diagnosis of H. pylori by tissue sections was found in all of the 26 cases (52 specimens). There was an excellent concordance (96.2%) between the morphological diagnosis of H. pylori in the Gram-stained imprint smears and the tissue sections. There was a good concordance (86.5%) between the histology and the bacterial culture. Interestingly, a different species of gastric campylobacter-like organism with similar morphological appearance was also cultivated. The results of rapid urease test are unsatisfactory because urease was detected in less than 10% of culture-positive biopsies after 1 hour and 71.1% after 24 hours. In summary, culture and histology are complementary to each other. The combination of both is the "gold standard" for confirming the presence of H. pylori. As for rapid diagnosis, the Gram-stained imprint smears are shown to give satisfactory results.
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PMID:Comparison of four different methods for detection of Helicobacter pylori from gastric biopsies. 209 2


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