Mycobacterial aetiology of sarcoidosis.
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Base Sequence↗
Biomedical subjects
D Y Graham
Publications and source records attributed to D Y Graham.
Effect of treatment of Helicobacter pylori infection on the long-term recurrence of gastric or duodenal ulcer. A randomized, controlled study.
OBJECTIVE: To determine the effect of treating Helicobacter pylori infection on the recurrence of gastric and duodenal ulcer disease. DESIGN: Follow-up of up to 2 years in patients with healed ulcers who had participated in randomized, controlled trials. SETTING: A Veterans Affairs hospital. PARTICIPANTS: A total of 109 patients infected with H. pylori who had a recently healed duodenal (83 patients) or gastric ulcer (26 patients) as confirmed by endoscopy. INTERVENTION: Patients received ranitidine, 300 mg, or ranitidine plus triple therapy. Triple therapy consisted of tetracycline, 2 g; metronidazole, 750 mg; and bismuth subsalicylate, 5 or 8 tablets (151 mg bismuth per tablet) and was administered for the first 2 weeks of treatment; ranitidine therapy was continued until the ulcer had healed or 16 weeks had elapsed. After ulcer healing, no maintenance antiulcer therapy was given. MEASUREMENTS: Endoscopy to assess ulcer recurrence was done at 3-month intervals or when a patient developed symptoms, for a maximum of 2 years. RESULTS: The probability of recurrence for patients who received triple therapy plus ranitidine was significantly lower than that for patients who received ranitidine alone: for patients with duodenal ulcer, 12% (95% CI, 1% to 24%) compared with 95% (CI, 84% to 100%); for patients with gastric ulcer, 13% (CI, 4% to 31%) compared with 74% (44% to 100%). Fifty percent of patients who received ranitidine alone for healing of duodenal or gastric ulcer had a relapse within 12 weeks of healing. Ulcer recurrence in the triple therapy group was related to the failure to eradicate H. pylori and to the use of nonsteroidal anti-inflammatory drugs. CONCLUSIONS: Eradication of H. pylori infection markedly changes the natural history of peptic ulcer in patients with duodenal or gastric ulcer. Most peptic ulcers associated with H. pylori infection are curable.
Adult↗
Treatment of nonsteroidal antiinflammatory drug-induced gastric ulcers with misoprostol. A double-blind multicenter study.
One hundred sixty-two patients chronically ingesting ibuprofen, piroxicam, or naproxen for osteoarthritis, who had abdominal pain and an endoscopically proven gastric ulcer were evaluated for eight weeks in a randomized, double-blind trial comparing misoprostol (200 micrograms four times daily with meals and at bedtime) (N = 77) with placebo (N = 85). Patients discontinued their usual daily dose of antiarthritic medication throughout the study period, and an endoscopy was performed at four weeks and eight weeks (if necessary) to assess ulcer healing. Gastric ulcers were defined as circumscribed breaks in the gastric mucosa of 0.3 cm in diameter or greater. Misoprostol therapy significantly accelerated the rate of gastric ulcer healing compared to placebo (P = 0.033). The cumulative percent healed after four and eight weeks of therapy for misoprostol versus placebo were: 83% vs 61% at four weeks and 96% vs 90% at eight weeks (P = 0.0028 and P = 0.0977, respectively by lifetable analysis). Relief of abdominal pain did not differ significantly between the treatment groups. Misoprostol significantly accelerates the healing of ibuprofen-, piroxicam-, or naproxen-induced gastric ulcers.
Anti-Inflammatory Agents, Non-Steroidal↗
Helicobacter pylori in Hispanics: comparison with blacks and whites of similar age and socioeconomic class.
Helicobacter pylori infection is twice as frequent in blacks as in whites. It has been postulated that the apparent increase in susceptibility to H. pylori infection in blacks might have a genetic basis. A case-control seroepidemiologic study of H. pylori prevalence was performed in 108 healthy Hispanic volunteers. Eighty-nine Hispanics were matched (1:1:1) with blacks and whites for age and socioeconomic status. There was an inverse correlation between H. pylori infection and educational level that remained after logistic regression analysis adjusting for age and sex. The adjusted prevalence of H. pylori infection was almost identical in Hispanics and blacks and significantly higher than in whites. Because Hispanics do not constitute a race, the increased prevalence of H. pylori in Hispanics and blacks is unlikely to be genetic. It is speculated that the unrecognized bias is a reflection of a generation cohort phenomenon related to the generational distance from very low socioeconomic status, i.e., the prevalence of H. pylori in Hispanics and blacks is currently lower than that of their parents but higher than that of the white population, which has experienced higher socioeconomic status for several generations.
Adult↗
Selection of the chimpanzee over the baboon as a model for Helicobacter pylori infection.
Baboons (Papio sp.) and chimpanzees (Pan troglodytes) were screened for the presence of Helicobacter pylori. The gastric mucosae of the baboons were colonized by large spiral bacteria. However, a group of adult chimpanzees were identified that were free of spiral gastric bacteria, with five animals being recruited into an H. pylori challenge study. These animals were inoculated orogastrically with one of four strains of H. pylori and followed for up to 26 weeks. H. pylori was established in one of these animals during a primary challenge and in two other animals on secondary challenge. It was shown that the chimpanzee can be infected with H. pylori and that the inflammatory response in these animals mimics that seen in humans. Infection was marked by an antibody response to H. pylori-specific antigens in two animals. It was observed that H. pylori antibody-negative chimpanzees had no apparent infection by H. pylori or related bacteria. Thus serological screening of chimpanzees can be used to identify candidate animals for further evaluation.
Animals↗
Factors influencing the eradication of Helicobacter pylori with triple therapy.
Helicobacter pylori infection has been associated with gastritis, duodenal ulcer, gastric ulcer, and the epidemic form of gastric carcinoma. Eradication of H. pylori infection has proven to be difficult. Recently, combinations of antimicrobial drugs have been shown to eradicate greater than 50% of infections; however, the results have proven variable, and the factors influencing effectiveness of therapy are unclear. In the present study, the effectiveness of a triple therapy for eradication of H. pylori infection was evaluated. Triple therapy consisted of 2 g tetracycline, 750 mg metronidazole, and five or eight tablets of bismuth subsalicylate daily in 93 patients (70 with duodenal ulcer, 17 with gastric ulcer, and 6 with simple H. pylori gastritis). Combinations of a sensitive urea breath test, serology, culture, and histology were used to confirm the presence of infection, eradication, or relapse. Eradication was defined as inability to show H. pylori greater than or equal to 1 month after ending therapy. The overall eradication rate was 87%. The factors evaluated for their effect on predicting eradication included age, gender, type of disease, duration of therapy, amount of bismuth subsalicylate [five or eight Pepto-Bismol tablets daily (Procter & Gamble, Cincinnati, OH)], and compliance with the prescribed medications. Stepwise regression showed that compliance was the most important factor predicting success; the success rate was 96% for patients who took greater than 60% of the prescribed medications and 69% for patients who took less. For those taking greater than 60% of the prescribed therapy, the eradication rates were similar (a) for patients receiving therapy for 14 days or when tetracycline and bismuth subsalicylate were taken for an additional 14 days; (b) for patients with duodenal ulcer, gastric ulcer, and simple H. pylori gastritis; and (c) whether five or eight bismuth subsalicylate tablets were taken. It is concluded that triple therapy is effective for eradication of H. pylori and that future studies need to take compliance into account for comparisons between regimens.
Adult↗
Relationship of Helicobacter pylori to serum pepsinogens in an asymptomatic Japanese population.
A seroepidemiologic study of the prevalence of Helicobacter pylori infection in Japan was performed, and the relationship between serum pepsinogen I and II levels (markers of gastritis and gastric atrophy) and H. pylori infection was investigated. Four hundred and eighteen asymptomatic children and adults were studied. The prevalence of anti-H. pylori immunoglobulin G antibody increased with age. For persons born after 1950, the frequency of H. pylori infection increased at approximately 1% per year; for those born before 1950 the prevalence was high (70%-80%) and relatively constant. Serum pepsinogen I and II levels were significantly higher in H. pylori-infected volunteers than in H. pylori-uninfected volunteers [51.6 +/- 3 vs. 42.9 +/- 2 ng/mL (P less than 0.05) for pepsinogen I; 16.0 +/- 1 vs. 7.5 +/- 0.8 ng/mL (P less than 0.001) for pepsinogen II]. The ratio of pepsinogen I to pepsinogen II was significantly lower in H. pylori-infected volunteers (3.5 +/- 0.2) than in uninfected volunteers (6.3 +/- 0.3; P less than 0.001). The apparent decrease in prevalence of H. pylori accompanying the Westernization of Japan may eventually be accompanied by a reduction in the frequency of atrophic gastritis, the precursor lesion of the epidemic form of gastric carcinoma, and ultimately result in a decrease in the incidence of gastric carcinoma in Japan.
Adolescent↗
Manometry in classic and vigorous achalasia.
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Esophageal Achalasia↗
Adherence and internalization of Helicobacter pylori by HEp-2 cells.
Helicobacter pylori colonizes the mucous layer of the stomach and the surface of gastric mucous cells. Although H. pylori is not generally thought of as invasive, it has been observed in the lamina propria and within vacuoles in the cytoplasm of epithelial cells. The authors report that isolates of H. pylori can enter into the cytoplasm of tissue culture epithelial cell lines such as HEp-2 cells. Intracellular uptake of H. pylori by HEp-2 cells is rapid and appears to require both the N-acetylneuraminyllactose-binding adhesin and another factor present only in living bacteria. Uptake of H. pylori was inhibited by ammonium chloride and chloroquine at concentrations that did not effect either adherence or bacterial viability. Dansylcadaverine, an inhibitor of receptor clustering and internalization, also inhibited uptake but not adherence of H. pylori. Uptake was completely inhibited when H. pylori and HEp-2 cells were incubated at 4 degrees C under conditions that did not effect bacterial adherence. Cytochalasin B, an inhibitor of phagocytosis, did not inhibit uptake. It is concluded that H. pylori is internalized either by receptor-mediated endocytosis or by a closely related pathway.
Adrenal Glands↗
Short report: cefprozil for the eradication of Helicobacter pylori infection.
Helicobacter pylori infection has proven to be extraordinarily difficult to eradicate. Antimicrobial monotherapies have been particularly disappointing, with most eradication rates in the range of 0 to 15%. We evaluated cefprozil (250 mg q.d.s. for 14 days) in 12 H. pylori-infected subjects. The 13C-urea breath test was used to evaluate effectiveness of therapy. Eradication was defined as a negative urea breath test 4 to 6 weeks after the end of treatment. Suppression of H. pylori was demonstrated in 4 of 12 (33%) by a negative urea breath test two days after start of treatment. H. pylori infection was not eradicated in any subject (0%). Adverse events were intermittent and mild. Cefprozil does not appear to offer promise as monotherapy for the eradication of H. pylori.
Adult↗
Review article: urease, gastric ammonium/ammonia, and Helicobacter pylori--the past, the present, and recommendations for future research.
The presence of ammonium in gastric contents was described in 1852; urease activity in the stomach was identified 70 years later. The discovery of gastric urease resulted in intense research activity to discover its origin, function, and relation to the gastric levels of ammonium and urea. Interest in urease waned in the 1960s as most pertinent questions appeared to have been addressed and there was strong evidence that gastric urease was not a property of the stomach but was of microbial origin. Identification of Helicobacter pylori as the source of urease in the stomach in the last decade has resulted in a rebirth of interest in gastric urease and its products. There is little actual evidence to support a role for toxicity of ammonia in relation to H. pylori and the bulk of the evidence suggests that the products of urease activity are not toxic and may even be beneficial. The purpose of this review is to examine the older literature and to examine new findings in the perspective of what is already known and to suggest areas remaining to be examined. We ask, 'What is old, what is new, and what needs to be done?'
Ammonia↗
Urease-associated heat shock protein of Helicobacter pylori.
Helicobacter pylori urease is an extracellular, cell-bound enzyme with a molecular weight of approximately 600,000 (600K enzyme) comprising six 66K and six 31K subunits. A 62K protein is closely associated with the H. pylori urease, both in crude preparations and after gel filtration; this protein can be removed from the urease by ion-exchange chromatography without inactivating the enzyme. We purified this urease-associated protein and determined its N-terminal amino acid sequence. The sequence is 80% homologous (identical plus conserved amino acid residues) to the Escherichia coli GroEL heat shock protein (HSP), 75% homologous to the human homolog, and 84% homologous to the HSP homolog found in species of Chlamydia. Thus, the 62K urease-associated protein of H. pylori belongs to the HSP60 family of stress proteins known as chaperonins. Evidently this protein, HSP62, participates in the extracellular assembly and/or protection of the urease against inactivation in the hostile environment of the stomach.
Amino Acid Sequence↗
Detection of Norwalk virus in stool by polymerase chain reaction.
A method of reverse transcription (RT) and polymerase chain reaction (PCR) for the detection of Norwalk virus in human stools was developed. A cationic detergent, cetyltrimethylammonium bromide, was found to effectively remove from stool extracts factors that inhibit the RT-PCR assay. The specificities of the tests were shown by hybridization of the amplified DNA with Norwalk virus-specific cDNA probes and a consistent correlation between virus detection in stools and infection of volunteers. RT-PCR detected virus in stool samples diluted 10(-4) and was about 100 times more sensitive than dot blot hybridization. In serial stool samples collected before and at different times after inoculation of 10 volunteers with Norwalk virus, 37 of 55 were positive by RT-PCR, but only 27 were positive by dot blot hybridization (chi 2 = 22.96; P less than 0.001). Further application of this method should allow detection of Norwalk virus in food or environmental samples such as shellfish and shellfish waters.
Adult↗
Reverse transcription and polymerase chain reaction amplification of rRNA for detection of Helicobacter species.
Sequence data on Helicobacter pylori 16S rRNA were used to select two 22-base oligonucleotide primers for use in a polymerase chain reaction (PCR) for detection of H. pylori. H. pylori cells were treated with lysis buffer, boiled, and chloroform extracted. Reverse transcription of rRNA was followed by PCR amplification (RT-PCR) of the synthesized cDNA and 16S rRNA gene. The amplified PCR products were analyzed by agarose gel electrophoresis and Southern blotting. Using ethidium bromide-stained agarose gels, we were able to detect the expected 500-bp DNA fragment from as few as two H. pylori organisms per reaction. The specificity of the RT-PCR assay was tested with 27 clinical isolates and related reference strains; although the number of bacterial cells used per reaction was 10(5)-fold greater than the number of H. pylori organisms used, amplification was detected only with bacteria in the same genus, H. cinaedi and H. mustelae. Ten H. pylori organisms per biopsy specimen were detected on agarose gels when organisms were added to samples prepared from a processed colon biopsy sample. RT-PCR results were consistent with urea breath test and culture results in 14 of 15 gastric biopsy specimens; the specificity was 100%. RT-PCR of rRNA from H. pylori increased the sensitivity of pathogen detection at least 25- to 50-fold compared with that of previous PCR assays. This low level of detection by RT-PCR assay may prove to be well suited for verifying eradication following therapy.
Base Sequence↗
Expression, self-assembly, and antigenicity of the Norwalk virus capsid protein.
Norwalk virus capsid protein was produced by expression of the second and third open reading frames of the Norwalk virus genome, using a cell-free translation system and baculovirus recombinants. Analysis of the expressed products showed that the second open reading frame encodes a protein with an apparent molecular weight of 58,000 (58K protein) and that this protein self-assembles to form empty viruslike particles similar to native capsids in size and appearance. The antigenicity of these particles was demonstrated by immunoprecipitation and enzyme-linked immunosorbent assays of paired serum samples from volunteers who developed illness following Norwalk virus challenge. These particles also induced high levels of Norwalk virus-specific serum antibody in laboratory animals following parenteral inoculation. A minor 34K protein was also found in infected insect cells. Amino acid sequence analysis of the N terminus of the 34K protein indicated that the 34K protein was a cleavage product of the 58K protein. The availability of large amounts of recombinant Norwalk virus particles will allow the development of rapid, sensitive, and reliable tests for the diagnosis of Norwalk virus infection as well as the implementation of structural studies.
Antibody Formation↗
Polymerase chain reaction detection of Mycobacterium paratuberculosis and Mycobacterium avium subsp silvaticum in long term cultures from Crohn's disease and control tissues.
Thirty one cultures were established in MG3 medium from the intestinal tissues of 29 patients, including 18 with Crohn's disease, five with ulcerative colitis, and six non-inflammatory bowel disease controls. All cultures grew either acid fast bacilli or uncharacterized spheroplasts. Pellets from these cultures were coded and assayed blind for M paratuberculosis and M avium subsp silvaticum using IS900- and IS902-PCR (polymerase chain reaction) assays, respectively. IS900 and IS902 are multicopy DNA insertion elements specific for these two organisms. Six Crohn's disease cultures and a single non-inflammatory bowel disease control were positive for M paratuberculosis. A further six cultures were positive for M avium subsp silvaticum, of which two each were from Crohn's disease, ulcerative colitis, and non-inflammatory bowel disease controls. The intensity of the IS900-PCR signals indicated very low numbers of M paratuberculosis organisms and bore no relation to visible spheroplastic or bacillary mycobacterial growth. The results suggest that M paratuberculosis isolated from man exists in a form which hardly replicates if at all when cultured in MG3 medium in vitro, and are consistent with the involvement of this known animal enteric pathogen in a proportion of chronic enteritis in man.
Base Sequence↗
Gastric adaptation to nonsteroidal anti-inflammatory drugs in man.
Adaptation describes the phenomenon in which visible gastric mucosal injury lessens or resolves completely despite continued administration of an injurious substance such as aspirin. Adaptation occurs in man although the mechanism remains unclear. Recent evidence suggests increased cell proliferation and correction of nonsteroidal anti-inflammatory drug induced reduction in gastric blood flow as possibly being important. Gastric erosions and ulcers in chronic nonsteroidal anti-inflammatory drug users represent failed adaptation. Gastric erosions and ulcers in chronic nonsteroidal anti-inflammatory drug users represent failed adaptation. The factors responsible for failure of adaptation are unknown but one clue is that there appears to be a dose-response effect relating anti-inflammatory dose and effectiveness of adaptation (i.e., adaptation is delayed, or less effective, when higher anti-inflammatory doses are administered). Gastric adaptation can be enhanced by co-therapy with synthetic prostaglandins but not with sucralfate or H2-receptor antagonists.
Adaptation, Physiological↗
Bile acid therapy for Helicobacter pylori.
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Bile Acids and Salts↗