Gastroenterology today and tomorrow.
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Forecasting↗
Biomedical subjects
D Y Graham
Publications and source records attributed to D Y Graham.
Effect of triple therapy (antibiotics plus bismuth) on duodenal ulcer healing. A randomized controlled trial.
OBJECTIVE: To determine whether antimicrobial therapy for Helicobacter pylori infection accelerates the healing of duodenal ulcers. DESIGN: Single-blind, randomized, controlled trial. SETTING: Veterans Affairs hospital. PARTICIPANTS: One hundred and five patients with endoscopically verified duodenal ulcers. INTERVENTION: Patients received either ranitidine, 300 mg/d, or ranitidine, 300 mg/d, plus "triple therapy" (2 g/d of tetracycline, 750 mg/d of metronidazole, and 5 or 8 bismuth subsalicylate tablets per day). Triple therapy was administered for only the first 2 weeks of ulcer treatment. MEASUREMENTS: Videoendoscopic assessment of ulcer status was done until ulcer healing was complete. Evaluations were done after 2, 4, 8, 12, and 16 weeks of therapy. MAIN RESULTS: Ulcer healing was more rapid in patients receiving ranitidine plus triple therapy than in patients receiving ranitidine alone (P less than 0.01). The cumulative percentages of patients with healed ulcers in the group receiving ranitidine plus triple therapy and in the group receiving ranitidine alone were as follows: 37% and 18% after week 2; 74% and 53% after week 4; 84% and 68% after week 8; 96% and 80% after week 12; and 98% and 84% after week 16. CONCLUSION: Combined therapy with anti-H. pylori agents and ranitidine was superior to ranitidine alone for duodenal ulcer healing. Our results indicate that H. pylori plays a role in duodenal ulcer disease.
Adult↗
Misoprostol compared with sucralfate in the prevention of nonsteroidal anti-inflammatory drug-induced gastric ulcer. A randomized, controlled trial.
OBJECTIVES: To compare the efficacy and frequency of adverse experiences of misoprostol and sucralfate in the prevention of gastric ulcers in patients receiving nonsteroidal anti-inflammatory drug (NSAID) therapy. DESIGN: A prospective, randomized, single-blind, multicenter trial. PATIENTS: Patients with osteoarthritis receiving treatment with ibuprofen, piroxicam, or naproxen and experiencing abdominal pain were eligible. INTERVENTIONS: Patients who were expected to receive at least 3 months of NSAID therapy and who did not have a gastric ulcer at the time of the initial screening endoscopy were randomized to receive misoprostol, 200 micrograms four times a day, or sucralfate, 1 g four times a day. A gastric ulcer was defined as a lesion of the gastric mucosa 0.3 cm or greater in diameter. Patients were followed clinically, and repeat endoscopies were performed after 4, 8, and 12 weeks. MAIN MEASUREMENT: The development of a gastric ulcer, which was regarded as a prophylaxis failure. RESULTS: Two hundred fifty-three patients were evaluable for efficacy analysis. A gastric ulcer developed in 2 of the 122 (1.6%, 95% CI, 0.3% to 6.4%) patients on misoprostol, compared with 21 of 131 patients on sucralfate (16%, CI, 10.4% to 23.7%). The difference in ulcer rates was 14.4% (CI, 10.4% to 19.5%; P less than 0.001). CONCLUSION: In patients receiving chronic NSAID therapy for osteoarthritis, treatment with misoprostol for 3 months was associated with a significantly lower frequency of gastric ulcer formation, compared with treatment with sucralfate (P less than 0.001).
Adult↗
Water source as risk factor for Helicobacter pylori infection in Peruvian children. Gastrointestinal Physiology Working Group.
Helicobacter pylori infection is widespread among Peruvian adults by the age of 30, but the age at which children become infected, the prevalence of disease, and the role of socioeconomic status in the epidemiology of infection are not known. We used the 13C-urea breath test to study the prevalence of infection in 407 Peruvian children from Lima, aged 2 months to 12 years, from families of low and high socioeconomic status. Peruvian children acquire H pylori early in life and the number of infected individuals increases rapidly with age; overall prevalence was 48%. H pylori infection was independent of sex, but was highly correlated with socioeconomic status; prevalence of infection was higher among children from low-income families than among those from high-income families (56% vs 32%, p = 0.001). Children whose homes had external water sources were three times more likely to be infected than were those whose homes had internal water sources. Among families with internal water sources, there was no difference in H pylori infection associated with income. Children from high-income families whose homes were supplied with municipal water were 12 times more likely to be infected than were those from high-income families whose water supply came from community wells. The findings show that the prevalence of H pylori infection is high among young Peruvian children and that the municipal water supply seems to be an important source of infection among Lima children from families of both low and high socioeconomic status.
Age Factors↗
Seroepidemiology of Helicobacter pylori infection in India. Comparison of developing and developed countries.
Helicobacter pylori (previously Campylobacter pylori) is now accepted as the major cause of type B gastritis and thus what is known about the epidemiology of type B gastritis can reasonably be transferred to H. pylori. We used a specific ELISA for anti-H. pylori IgG to study the prevalence of H. pylori infection in a population of lower socioeconomic class from Hyderabad, India. The results from India were compared to studies from other parts of the world. Two hundred thirty-eight individuals ages 3 to 70 participated. The frequency of H. pylori infection increased with age (P less than 0.01) and was greater than 80% by age 20. H. pylori infection was present in 79% of the population studied; there was no gender-related difference in prevalence of H. pylori infection. IgG antibody against hepatitis A (HAV) was rapidly acquired in Hyderabad; in a subset of 58 children between the ages of 3 and 21 tested, the frequency of anti-HAV was 98.2%. The prevalence of H. pylori infection increases with age in both developed and developing countries. The high age-specific prevalence of H. pylori infection in developing countries is probably a reflection of the lower socioeconomic level of those areas.
Developing Countries↗
Antimony electrodes for in vivo pH monitoring.
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Antimony↗
Investigations on etiology of Crohn's disease. Humoral immune response to stress (heat shock) proteins.
Many investigators have tried to prove a relationship between Crohn's disease and Mycobacteria. Recent evidence suggests that some autoimmune diseases may be initiated through "molecular mimicry" between mycobacterial stress protein antigens and their human homologs. We investigated whether antibody to stress proteins was more frequent in patients with Crohn's disease than controls. We used ATP binding to separate stress proteins (heat-shock-induced, de novo-synthesized, and constitutively expressed ATP-binding proteins) from crude extracts obtained from Mycobacteria and from an SV40-transformed human epithelial cell line that expresses a heat-shock protein, hsp73, as a complex with SV40 T antigen. We used immunoblots to compare sera from 34 patients with Crohn's disease, 14 with ulcerative colitis, and 14 with duodenal or gastric ulcers (noninflammatory bowel disease control patients). We found no statistically significant pattern or frequency of antibodies against single proteins or a combination of mycobacterial or human stress proteins. These observations do not support the hypothesis that a humoral immune response to stress proteins of Mycobacteria is important in the pathogenesis of Crohn's disease.
Antibody Formation↗
Helicobacter pylori and Zollinger-Ellison syndrome.
Helicobacter pylori (previously Campylobacter pylori) is almost invariably associated with chronic duodenal ulcer disease. The relationship between H. pylori infection and duodenal ulcer in Zollinger-Ellison syndrome is unknown. We investigated the frequency of H. pylori infection in Zollinger-Ellison syndrome and also what effect H. pylori infection had on gastric function in patients with Zollinger-Ellison syndrome. H. pylori infection was diagnosed based on a specific serologic (ELISA) assay based on high-molecular-weight cell-associated proteins of H. pylori. We studied 20 patients with Zollinger-Ellison syndrome; 15 men and 5 women ranging in age from 24 to 71 years, median age 51. Six Zollinger-Ellison syndrome patients had H. pylori infection compared to 100 consecutive patients with chronic recurrent duodenal ulcer disease (P less than 0.05). Pretreatment basal acid output in Zollinger-Ellison syndrome patients ranged from 7.9 to 95.0 mmol/hr, median 35.2. Pentagastrin-stimulated maximal acid output ranged from 8.5 to 132 mmol/hr; median 52.7. Acid secretion was lower in the H. pylori-infected patients than the uninfected patients (BAO 24.5 +/- 6.5 vs 45.4 +/- 6.6, and MAO 44.3 +/- 11.8 vs 67.9 +/- 10.7, for H. pylori infected vs uninfected patients, respectively). The difference in BAO was statistically significant (P less than 0.05). The present results indicate that H. pylori is not a major contributing factor in duodenal ulcer associated with Zollinger-Ellison syndrome. The association of a reduced BAO with H. pylori suggests that these findings may be related.
Adult↗
Epidemiology of Helicobacter pylori in an asymptomatic population in the United States. Effect of age, race, and socioeconomic status.
A causative role is now accepted for Helicobacter (formerly Campylobacter) pylori in type B gastritis, and evidence is accumulating that H. pylori infection plays a major contributory role in peptic ulcer disease. Preliminary studies have reported that the prevalence of H. pylori infection increases with age, but detailed information on the prevalence of the bacteria in any defined population and on the factors that may influence the pattern of distribution remains scanty. In the present study, a sensitive enzyme-linked immunosorbent assay and a [13C] urea breath test were used to investigate the prevalence of H. pylori infection among 485 healthy asymptomatic volunteers between the ages of 15 and 80 residing in the Houston metropolitan area. H. pylori infection was present in 52%. The prevalence of H. pylori infection increased rapidly with age at 1%/yr for the overall population. The frequency of H. pylori infection was higher in blacks (70%) than whites (34%) (P less than 0.001); this difference remained after adjustments were made for age, gender, educational level, income, and use of tobacco or alcohol. H. pylori infection was independent of gender but was closely correlated with socioeconomic class. There were significant inverse correlations between age-adjusted frequency of H. pylori infection and income and between educational level and H. pylori infection. There was no association between H. pylori infection and consumption of alcohol or nonsteroidal antiinflammatory drug use or smoking. Having pets was associated with a lower frequency of H. pylori infection, but this was highly associated with higher socioeconomic status. The mode(s) of transmission of H. pylori is unknown, but the social patterns of H. pylori infection are consistent with fecal-oral transmission as one important pathway. Socioeconomic factors seem to determine the age of acquisition.
Adolescent↗
Helicobacter pylori-associated exaggerated gastrin release in duodenal ulcer patients. The effect of bombesin infusion and urea ingestion.
Recent studies have shown that the exaggerated meal-stimulated gastrin release in patients with duodenal ulcer abates after eradication of Helicobacter pylori infection. Bombesin-stimulated gastrin release was compared in 11 H. pylori-infected patients with chronic duodenal ulcer and 8 uninfected healthy volunteers both before and after therapy to eradicate H. pylori. Bombesin infusion significantly increased the gastrin release both in control subjects and in patients with duodenal ulcer. Antimicrobial therapy (bismuth, tetracycline, and metronidazole) to eradicate the H. pylori infection was associated with a significant reduction in bombesin-stimulated gastrin release in patients with duodenal ulcer (from 116.9 +/- 19 pg/mL to 69.5 +/- 7 pg/mL following 50 pmol.kg-1.h-1 bombesin; and from 158 +/- 29 to 83.4 +/- 10 following 200 pmol.kg-1.h-1 bombesin: P = 0.01 for each). Antimicrobial therapy had no effect on gastrin release in uninfected volunteers, thus excluding a nonspecific effect of antimicrobial therapy on antral G-cell function. Serum gastrin was also not increased by feeding 500 mg of urea to 5 H. pylori-infected volunteers. This suggests that access of hydrogen ion to the pH-sensitive sites governing gastrin release by mucosal ammonia produced by H. pylori urease is not a critical factor. These data suggest that exaggerated gastrin release present in patients with duodenal ulcer disease is secondary to H. pylori infection.
Adult↗
Long-term nonsteroidal antiinflammatory drug use and Helicobacter pylori infection.
This study investigates whether patients who take nonsteroidal antiinflammatory drugs are more likely to have Helicobacter pylori gastritis than age-matched individuals who do not take nonsteroidal antiinflammatory drugs, and whether patients who take nonsteroidal antiinflammatory drugs who are also infected with H. pylori are more likely to have dyspepsia, mucosal damage, or ulcers than those who are not infected. Two studies were performed, one serological and the other endoscopic, both in arthritis patients receiving nonsteroidal antiinflammatory drugs chronically. The presence of H. pylori was identified with a sensitive enzyme-linked immunosorbent assay test. One hundred eighty-three patients participated in the serological study and 75 patients in the endoscopic study. The frequency of H. pylori infection increased with age, independent of nonsteroidal antiinflammatory drug use; the age-adjusted frequency of H. pylori infection in arthritis patients paralleled that of 351 asymptomatic individuals without arthritis. The frequency of H. pylori infection increased from 30.7% in age group 21-30 years to 73.4% in age group 61-75 years. Nonsteroidal antiinflammatory drug-induced mucosal injury, either hemorrhages or erosions, was more frequent in those without H. pylori infection than with infection (61% vs. 32% for hemorrhages and 57% vs. 34% for erosions for those without and with H. pylori infection; only the difference in the frequency of hemorrhages was significant, P less than 0.05). No difference was observed in the presence of dyspeptic symptoms between those with and without H. pylori infection. These data suggest that nonsteroidal antiinflammatory drug-induced damage to the gastroduodenal mucosa does not increase the susceptibility to H. pylori infection.
Adult↗
Pathogenesis and treatment of rotavirus diarrhea.
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Animals↗
Iron represses the expression of CFA/I fimbriae of enterotoxigenic E. coli.
Experiments were designed to study the effect of iron on the expression of CFA/I fimbriae by enterotoxigenic E. coli (ETEC). Addition of 0.05 mM ferrous sulfate to growth media decreased CFA/I antigen and fimbrial production by the CFA/I-positive ETEC strain H-10407 as measured by quantitative ELISA and hemagglutination assay. The repressive effect was reversed by the addition of the iron chelators, sodium citrate or dipyridyl. With a CFA/I subunit gene promoter-lacZ fusion, it was found that the activity of the subunit gene promoter was significantly higher in the presence of iron chelators than in medium containing iron in the fur+ strain DHB24. This difference was not observed in the fur mutant strain SBC24, suggesting that the global E. coli metalloregulatory protein Fur (ferric uptake regulation) is involved in the repression. The repressor may bind to the promoter of the CFA/I subunit gene since several potential Fur-binding sites were identified in the promoter area.
Antigens, Bacterial↗
Characterization of the Helicobacter pylori urease and purification of its subunits.
Helicobacter pylori (formerly Campylobacter pylori) is the causative agent of gastritis in man. Helicobacter pylori cells contain a large amount of an extremely active urease (E.C.3.5.1.5). This enzyme is suspected to be a virulence factor since the ammonium ion produced from urea may be responsible for tissue injury and/or survival of H. pylori in the gastric environment. Helicobacter pylori urease, native relative molecular mass approximately 600,000, was purified by agarose gel filtration and ion exchange chromatography. DEAE-purified urease is highly active and has a Km of 0.48 mM for urea. The enzyme has a pI of 5.93 and is active from pH 4.0 to 10.0, with an optimum at pH 8.0. The purified urease contains nickel and is composed of two protein subunits, with relative molecular masses of 66,000 and 31,000. The subunits were separated and purified and the first 30 N-terminal amino acid residues were determined. A remarkably close relationship was found between both H. pylori urease subunits and jack bean (Canavalia ensiformis) urease, the subunit of which is a single 840 amino acid polypeptide. This subunit is also largely identical to the high molecular mass subunits of the ureases of Klebsiella aerogenes and Proteus mirabilis, evidence that these four ureases are derived from a common ancestral protein.
Amino Acid Sequence↗
Unidirectional water absorption as a measure of intestinal surface area in rats.
Methods to measure expeditiously the anatomic and functional mucosal surface area of the small intestine are needed. We postulated that passive, unidirectional water flux would assess the anatomic mucosal surface area and that the increase in unidirectional flux that occurs in the presence of glucose would correlate with functional surface area. These hypotheses were tested in control and methotrexate-treated rats. A single-pass perfusion technique was used in vivo. Methotrexate treatment reduced anatomic and functional surface area (p less than 0.05) as measured by computerized planimetry, wet mucosal weight, sucrase activity, and sucrase activity normalized to mucosal DNA content. A formula to predict anatomic surface area was derived from control animal data. The best model used passive, unidirectional water flux as the independent variable, but this model overestimated mucosal surface area in the methotrexate-treated animals (p less than 0.01). Mean unidirectional water flux increased by 45% (p less than 0.01) in controls during glucose perfusion, but did not increase in methotrexate-treated animals (p greater than 0.37). Thus, unidirectional water flux cannot be used as a universally applicable method to assess the anatomic mucosal surface area, but glucose-enhanced unidirectional water flux should be evaluated further as an indirect measure of functional surface area.
Animals↗
Helicobacter pylori catalase.
Helicobacter pylori is the major aetiological agent of gastroduodenitis in humans. Due to the potential importance of catalase in the growth and survival of Helicobacter pylori on the surface of inflamed mucosae, we have characterized catalase from H. pylori as a prelude to further studies on the function of the enzyme in vivo. The catalase activity of H. pylori was significantly affected by the presence of blood, serum or erythrocytes in the growth medium: the greatest activity was expressed when the bacterium was grown on medium containing serum. H. pylori catalase is a tetramer with a subunit Mr of 50,000. The enzyme had a pI of 9.0-9.3, was active over a broad pH range and was stable at 56 degrees C. It was non-competitively inhibited by sodium azide, and had no detectable peroxidase activity. The Km for the purified catalase was measured as 43 +/- 3 mM-H2O2 and the V as 60 +/- 3 mmol H2O2 min-1 (mg protein)-1. The native catalase has absorption maxima at 280 nm and 405 nm with further minor shoulders or peaks at 510 nm, 535 nm and 625 nm, consistent with the presence of an iron-porphyrin prosthetic group.
Azides↗
Serologic and mucosal immune response to rotavirus infection in the rabbit model.
We examined the humoral immune response to rotavirus infection in specific pathogen-free rabbits inoculated and challenged orally with rabbit Ala rotavirus (7.5 x 10(5) to 1 x 10(7) PFU). The humoral immune response in both serologic and mucosal samples was monitored by using total antibody enzyme-linked immunosorbent assays (ELISAs), isotype-specific ELISAs, and plaque reduction neutralization assays. Following a primary infection, all rabbits shed virus and serologic and mucosal antibody responses were initially detected by 1 week postinoculation. Intestinal immunoglobulin M was detected by 3 days postinoculation, and secretory immunoglobulin A was detected by 6 days postinoculation. Following challenge, rabbits were protected (no detectable virus shedding) from infection. An anamnestic immune response was observed only with mucosal neutralizing antibodies, and all serologic and mucosal immune responses persisted at high levels until at least 175 days postchallenge (204 days postinoculation). Detection of neutralization responses was influenced by the virus strain used in the neutralization assay; all inoculated rabbits developed detectable serum and intestinal neutralizing antibodies against the infecting (Ala) virus strain. Neutralization activity in both serum and mucosal samples was generally, but not exclusively, homotypic (VP7 serotype 3) after both primary and challenge inoculations with Ala virus. Heterotypic serum neutralization activity was observed with serotype 8 (9 of 12 rabbits) and 9 (12 of 12 rabbits) viruses and may be based on reactivity with the outer capsid protein VP4 or on a shared epitope in the C region of VP7. Comparisons of heterologous (serotype 3) and heterotypic neutralizing responses in mucosal and serologic samples revealed that 43% (21 of 49) of the responses were discordant. In 19 of 49 (39%) of these cases, a heterotypic serologic response was seen in the absence of a heterotypic mucosal response, but in 2 of 49 (4%) instances, a heterotypic mucosal response was seen in the absence of a concomitant serologic response. These results provide insight into factors which may affect detection of heterotypic responses.
Animals↗
Transmission of Helicobacter pylori infection. Studies in families of healthy individuals.
Helicobacter pylori is accepted as the commonest cause of type-B gastritis. Detailed information about the mode of transmission remains scanty. We investigated the frequency of H. pylori infection within families, defined as consisting of a husband and wife with at least one biologic child, all living in the same household. Inclusion criteria required that both the parents and the children had been born in the United States, had used no antibiotic or bismuth for the previous 2 months, had no recent major illness or surgical operation, and had no symptoms referable to the upper gastrointestinal tract. H. pylori infection was identified with a 13C-urea breath test and an enzyme-linked immunosorbent assay for anti-H. pylori IgG. Forty-one families (151 healthy individuals) were enrolled. Before the results of the H. pylori tests were known, one parent was selected as the index subject. H. pylori infection clustered; that is, 68% of spouses of H. pylori-infected index subjects were also H. pylori-infected, compared with 9% of spouses of H. pylori-negative index subjects (p less than 0.0001). The children of infected index parents were also more likely to be infected than children of uninfected index parents--40% versus 3%, respectively (p less than 0.0001)--and the results in the children were independent of whether the father or the mother was the index subject. Clustering of H. pylori infection within families suggests person-to-person transmission or common source exposure. The high frequency of H. pylori infection in spouses suggests that genetic factors are less important than living conditions for transmission of H. pylori infection.
Adolescent↗