Unique features ofHelicobacter pylori disease in children

In a six-year period, 41 children had endoscopically documented duodenal ulcer disease or primaryH. pylori antral gastritis without duodenal ulcer. Of 37 children withH. pylori gastritis, group 1 comprised 23 patients with duodenal ulcer disease and group 2 had 14 patients without ulcers (primaryH. pylori gastritis). Group 3 comprised four children with duodenal ulcer disease andH. pylori-negative antral biopsies. During the study period, all primary chronic ulcer disease was duodenal; no primary chronic gastric ulcer was present. Two distinct types of duodenal ulcer disease were identified; the majority (85%) was always associated with significant activeH. pylori antral gastritis (group 1). The minority (15%) had virtually absent gastritis and noH. pylori (group 3). Native Indian children were represented in group 1 quite out of proportion to the referral population and had the most severe disease. While it is established that a higher prevalence of asymptomaticH. pylori infection exists in non-Caucasians, this appears to be the first demonstration of a higher prevalence of symptomatic ulcer disease in non-Caucasian children or adults. Caucasian children tended to have primaryH. pylori gastritis (group 2) or duodenal ulcer withoutH. pylori (group 3). Antral nodularity was found to be an important specific endoscopic sign, unique to those children withH. pylori disease. It has not been described in adultH. pylori disease. Non-Caucasian children, especially Native Indians, in British Columbia have more prevalent and more severeH. pylori disease than Caucasians. Endoscopy with gastric antral biopsies is necessary to distinguish different types of duodenal ulcer disease and to diagnose primaryH. pylori gastritis.     

DNA-DNA hybridization demonstrates apparent genetic differences betweenHelicobacter pylori from patients with duodenal ulcer and asymptomatic gastritis

We asked whether different clinical outcomes ofHelicobacter pylori infection might be a reflection of genetic differences in infecting organisms. Using DNA-DNA hybridization we examined whether hybridization levels groupedH. pylori isolates corresponding to the type of disease (gastric ulcer, duodenal ulcer, asymptomatic gastritis) from which they were recovered. Target DNAs were prepared fromH. pylori strains cultured from gastric biopsy specimens of 25 patients; 5 with gastric ulcers, 9 with duodenal ulcers, and 11 from asymptomatic volunteers endoscopically proven not to have peptic ulcer disease. DNA-DNA hybridization was performed with whole genomic probes made from an isolate from each of the three disease categories. Using a DNA probe from an isolate from a duodenal ulcer patient, we found that isolates from patients with duodenal ulcer and nonulcer gastritis yielded significant differences in levels of hybridization. The levels of hybridization of DNA fromH. pylori isolates from duodenal ulcer patients, gastric ulcer patients and nonulcer gastritis controls were 85.5%±7%, 83%±3%, and 78.3%±5%, respectively (mean±sd), and the difference between the hybridization levels obtained with duodenal ulcer and nonulcer control target DNAs was statistically significant (P=0.025). These data suggest that the outcome of infection (eg, ulcer or no ulcer) may be due to virulence factors encoded by genomic DNA. If such differences exist, it should be possible to produce probes that would identify the ulcer virulence gene(s) and clearly distinguish between ulcerogenic and nonulcerogenic strains ofH. pylori.This work was supported by Veterans Affairs; by grant DK 39919 from the National Institute of Diabetes and Digestive and Kidney Diseases and by the generous support of Hilda Schwartz.     

Gastric emptying andHelicobacter pylori infection in duodenal ulcer disease

The pathogenetic link betweenHelicobacter pylori gastritis and duodenal ulcer is still unknown. Fast gastric emptying of liquids might be important in the pathogenesis of gastric metaplasia of the duodenum and duodenal ulcer through an increased exposure of the duodenum to gastric acid. InH. pylori-infected subjects, an abnormal gastric emptying could affect urea breath test results and correlate with the histological gastritis. This study was performed to evaluate the gastric emptying of liquids in duodenal ulcer patients withH. pylori infection and the possible relation between the bacterial load, gastric emptying, and urea breath test results. Seventeen duodenal ulcer patients withH. pylori gastritis and 15 healthy volunteers were studied by a combined [¹⁴C]octanoic acid and [¹³C]urea breath test to evaluate gastric emptying rate andH. pylori status simultaneously. Endoscopy with antral biopsies was performed in all duodenal ulcer patients. Duodenal ulcer patients withH. pylori infection have a normal liquid gastric emptying that is unrelated with the histological severity of gastritis. The urea breath test results and the gastric emptying parameters do not correlate with histology. A significant correlation between the gastric emptying and the urea hydrolysis rate is found. It is concluded thatH. pylori infection in duodenal ulcer patients is not associated with abnormally fast liquid gastric emptying, and this finding should be taken into account when a causal link betweenH. pylori infection and duodenal ulcer disease is searched for. The correlation between gastric emptying and urea hydrolysis rate explains why no conclusions on intragastric bacterial load can be drawn from the urea breath test results.This study was presented in part as an oral communication at the Annual Meeting of the American Gastroenterological Association, May 1994, New Orleans, and published in abstract form inGastroenterology 106:A160, 1994.     

No Protective Role of Helicobacter pylori in the Pathogenesis of Reflux Esophagitis in Patients with Duodenal or Benign Gastric Ulcer in Korea

Little is known about the relationship between H. pylori infection and reflux esophagitis. To evaluate whether or not H. pylori plays a protective role in the pathogenesis of reflux esophagitis, the prevalence rates of reflux esophagitis depending on H. pylori status in consecutively diagnosed duodenal ulcer or benign gastric ulcer patients were evaluated. In addition, the incidence rates of reflux esophagitis depending on H. pylori status were evaluated for those patients who received follow-up endoscopy at least 6 months after eradication treatment. The prevalence rates of reflux esophagitis were 8.0% (2 patients) in the 25 H. pylori-negative duodenal ulcer group patients and 6.5% (36 patients) in the 555 H. pylori-positive duodenal ulcer group patients, and there was no statistical difference. Similarly, that of gastric ulcer patients was 9.4% (32 patients) in the 340 H. pylori-positive group patients, slightly higher than that in the 41 H. pylori-negative group patients 4.9% (2 patients), but without statistical significance. After eradication treatment the reflux esophagitis incidence rates were 2.5% (2 patients) in the 81 H. pylori-eradicated duodenal ulcer group patients and 7.7% (3 patients) in the 39 noneradicated duodenal ulcer group patients, and there was no statistical difference. Similarly, those of gastric ulcer patients were 6.8% (3 patients) in the 44 H. pylori-eradicated and 8.7% (2 patients) in the 23 noneradicated group patients again without statistical difference. These results suggest that H. pylori does not play a protective role in the pathogenesis of reflux esophagitis in patients with duodenal or gastric ulcer in Korea.     

Helicobacter pylori cagA Status and Peptic Ulcer Disease in Iran

Helicobacter pylori contributes to the development of peptic ulcers and atrophic gastritis. Furthermore, H. pylori strains carrying the cagA gene are more virulent than cagA -negative strains and are associated with the development of gastric adenocarcinoma. The cagA gene is a putative H. pylori virulence factor of unknown function. The aim of this study was to determine the prevalence of the cagA gene among H. pylori isolates and its relationship with peptic ulcer disease in 128 Iranian patients. A total of 107 (83.6%) samples were positive, including 40 (95%) of the 42 patients with duodenal ulcer, 43 (86%) of the 50 patients with gastric ulcer, and 24 (66.6%) of the 36 patients with gastritis. cagA was present in 32 (80%) of 40 strains from duodenal ulcer patients, 33 (77%) of 43 strains from gastric ulcer patients, and 11 (46%) of 24 from gastritis patients. We also attempted to investigate the subtypes of 3′ region of cagA gene in H. pylori strains isolated from Iranian patients and their relation to H. pylori-associated gastroduodenal diseases. The PCR product of cagA positive strains obtained with primer set CAG1/CAG2 differed in size, varying from 642 to 651 bp (subtype A) in 33 isolates to 756 bp (subtype B/D) in 13 isolates. This does not support the view that subtypes of the 3′ region of cagA gene in H. pylori isolated from Iran correlate with the clinical outcomes of H. pylori, but colonization with cagA positive strains was significantly higher among duodenal ulcer than gastritis patients in Iran.     

Nodular Gastritis: An Endoscopic Indicator of <Emphasis Type="Italic">Helicobacter Pylori</Emphasis> Infection

We prospectively assessed the relationship between nodular gastritis and Helicobacter pylori infection. Of 1409 adults who underwent endoscopy for persistent dyspepsia between June 2004 and August 2005, 41 (2.9%) patients were diagnosed with nodular gastritis (11 [27%] men and 30 [73%] women). The mean age was 45.9 years. A control group of 65 patients without nodular gastritis was also evaluated. The prevalence of H. pylori infection was higher in patients with nodular gastritis than in controls (38/41 [93%] vs. 33/65 [51%]). Of 21 patients treated to eradicate H. pylori, the nodular gastritis pattern resolved or improved in 16 patients on subsequent endoscopy. This study suggests that a nodular pattern of the gastric mucosa on endocscopy is a good indicator for H. pylori infection in adults, with the high positive predictive value of 92.7%.     

Helicobacter pylori in duodenal ulcer patients with idiopathic gastric acid hypersecretion

Thirty-three consecutive patients with idiopathic gastric acid hypersecretion (defined as a basal acid output >10.0 meq/hr with a normal fasting serum gastrin level and negative secretin stimulation test) who were being treated for duodenal ulcer disease and other acid-peptic disorders were evaluated for the presence ofHelicobacter pylori by means of a rapid urease test. Fourteen patients had duodenal ulcer and 19 had other acid-peptic disorders (gastroesophageal reflux in 14, including six with Barrett's esophagus; four with nonulcer dyspepsia; and one with erosive gastritis).Helicobacter pylori was present in 12 of the 14 ulcer patients (86%) compared to only two of the 19 nonulcer patients (11%) (P<0.0001). The distribution of basal acid output for patients with duodenal ulcer was similar to that for nonulcer patients, and no significant difference in the mean basal acid output was found amongHelicobacter pylori-positive compared toHelicobacter pylori-negative patients. Seven of the duodenal ulcer patients with a basal acid output greater than 15.0 meq/hr wereHelicobacter pylori-positive, suggesting that the organism can withstand even extreme levels of gastric acidity. In conclusion, this study demonstrates that the prevalence ofHelicobacter pylori infection in patients with duodenal ulcer disease associated with idiopathic gastric acid hypersecretion is not different from a majority of ulcer patients with normal acid secretory profiles and offers additional evidence that extreme levels of gastric acid are not bactericidal for the organism.     

Zollinger-Ellison syndrome

SinceHelicobacter pylori infects the gastric mucosa in most patients with chronic duodenal ulcer, infection with this organism has been implicated in the pathogenesis of this common disease. We postulated that ifH. pylori is pathogenic in the usual type of duodenal ulcer, it should be less common when duodenal ulcer has another, specific etiology, such as Zollinger-Ellison syndrome. Gastric mucosa was compared from 18 patients with proven Zollinger-Ellison syndrome (17 of whom had had duodenal ulcer disease) and 18 controls with chronic duodenal ulcer without such a diagnosis. All subjects, who were matched for age and sex, had undergone elective gastric resections. Gastric tissues were stained by hematoxylin-eosin and Giemsa and were reviewed by an experienced pathologist who was unaware of the diagnosis. The frequency ofH. pylori in patients with Zollinger-Ellison syndrome (8/18) was lower than in controls with duodenal ulcer (16/18;P<0.02). Moreover, chronic antral gastritis scores were higher in patients with duodenal ulcer (P<0.01). In Zollinger-Ellison syndrome, peak acid output was lower in patients positive (median 22 meq/30 min) compared to those negative forH. pylori (median 32 meq/30 min;P<0.02) but serum gastrin was correspondingly lower in patients positive forH. pylori (P<0.05).H. pylori infection appears to be more frequent when duodenal ulceration is not associated with another etiology, such as acid hypersecretion in Zollinger-Ellison syndrome.H. pylori infection in Zollinger-Ellison syndrome may also be associated with decreased gastric acid secretion.Supported in part by grant DK34988 from the National Institutes of Health, U.S. Public Health Service.This work was presented in part at the American College of Gastroenterology Annual Meeting, New Orleans, October 1989, and published in abstract form in theAmerican Journal of Gastroenterology (84:1159, 1989).     

High acid secretion may protect the gastric mucosa from injury caused by ammonia produced by Helicobacter pylori in duodenal ulcer patients

The aim of the present study was to investigate the mechanism by which gastric atrophy does not tend to occur in patients with duodenal ulcer despite frequent Helicobacter pylori infection. This investigation was performed in 60 patients with duodenal ulcer and 63 age-matched gastritis patients. Endoscopic findings in the antrum and corpus were classified as normal, atrophic and superficial changes. Biopsy specimens were taken from the antrum and corpus. Ninety per cent of patients with duodenal ulcer and 63.5% of patients with gastritis had H. pylori infection (P<0.01). The incidence of normal findings in duodenal patients was 30% in antral regions and 50% in the corpus (P<0.05). Atrophic change was observed in 21.7% of patients in the antrum and 3.3% of patients in the corpus (P<0.01). The grade of inflammation in duodenal ulcer specimens was significantly higher in the antrum than in the corpus (P<0.01). >H. pylori density was significantly higher in the antrum than in the corpus in ulcer patients (P<0.01). No significant difference in endoscopic findings, >H. pylori density or the grade of inflammation was found between the antrum and corpus in patients with gastritis. The mean intragastric ammonia concentration was 10.3 mg/dL in duodenal ulcer patients and 6.2 mg/dL in gastritis patients (P<0.01). The mean pH was 3.5 and 4.6 in ulcer and gastritis specimens, respectively (P<0.01). Our data suggest that gastric mucosa injury is less frequently associated with duodenal ulcers than with gastritis due to the low >H. pylori density in the corpus and to the higher acid output that neutralizes the ammonia produced by H. pylori.     

A Follow-up Study on the Effect of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> Eradication on the Severity of Gastric Histology

Helicobacter pylori genetic diversity and geographic distribution affect the severity of gastric histology; while eradication heals gastritis, the improvement of atrophy and intestinal metaplasia (IM) is still controversial. We investigated whether H. pylori infection and genotypes (cagA–vacA) influence the histological changes and whether eradication resolves these changes. Twenty-one patients (11 duodenal ulcer, 2 gastric ulcer, 8 gastritis) received treatment. Biopsies for CLO, PCR, histology, and culture were collected before and at 1 and 12 months after treatment, and serum samples at 0, 1, 2, 6, and 12 months. H. pylori eradication was achieved in 71% of the patients. Histological scores for H. pylori densities were significantly higher in the antrum and incisura angularis. Scores for mononuclear cell and neutrophil infiltration were significantly higher in regions with a high H. pylori density and improved progressively after eradication. Eight patients with atrophy including five with IM showed no significant changes 12 months after eradication. The cagA gene, detected in 13 (62%), the vacA-s1a gene, in 20 (95%), and the vacA-m1 gene, in 12 (57%) of 21 patients were significantly associated with duodenal ulcer. A gradual decline in antibody titer reached an average of 67% 12 months after eradication. H. pylori infection and the associated genotypes (cagA of Western type) affect the severity of the gastric histology (mild forms of atrophy and IM) and the disease outcome. Eradication of H. pyloriresulted in healing of gastritis, but with no significant improvement in atrophy or IM.     

Has Peptic Ulcer Disease Changed During the Past Ten Years in Korea? A Prospective Multi-center Study

Background The incidence of H. pylori-negative, idiopathic peptic ulcer disease (IPUD) seems to be increasing with the changing trends of PUD and H. pylori infection in some developed countries. Aim To investigate the changing trend of PUD and the prevalence of H. pylori infection during the last decade and the prevalence of IPUD in Korea. Methods We prospectively evaluated H. pylori infection and the characteristics of PUD in 895 patients with newly diagnosed PUD from September 2004 to February 2005. Results The H. pylori infection rate in PUD was 72.0% and the proportion of IPUD was 22.2%. The proportion of gastric ulcer (GU) has significantly increased (47.8% vs. 44.3%) and the proportion of duodenal ulcer (DU) has significantly decreased (38.9% vs. 44.9%) compared with ten years ago. The changing trend in the prevalence of H. pylori infection in GU and DU showed an increase in GU (66.1% vs. 73.1%, P = 0.014) and a decrease in DU (79.3% vs. 68.1%, P = 0.001). Conclusion Compared with our results of ten years ago, there has been a significant change in the distribution of PUD and in the prevalence of H. pylori infection in GU and DU. Patients with IPUD are not uncommon in Korea.     

History of Helicobacter pylori,duodenal ulcer,gastric ulcer and gastric cancer

Helicobacter pylori(H.pylori)infection underlies gastric ulcer disease,gastric cancer and duodenal ulcer disease.The disease expression reflects the pattern and extent of gastritis/gastric atrophy(i.e.,duodenal ulcer with non-atrophic and gastric ulcer and gastric cancer with atrophic gastritis).Gastric and duodenal ulcers and gastric cancer have been known for thousands of years.Ulcers are generally non-fatal and until the 20th century were difficult to diagnose.However,the presence and pattern of gastritis in past civilizations can be deduced based on the diseases present.It has been suggested that gastric ulcer and duodenal ulcer both arose or became more frequent in Europe in the 19th century.Here,we show that gastric cancer and gastric ulcer were present throughout the 17th to 19th centuries consistent with atrophic gastritis being the predominant pattern,as it proved to be when it could be examined directly in the late 19th century.The environment before the 20th century favored acquisition of H.pylori infection and atrophic gastritis(e.g.,poor sanitation and standards of living,seasonal diets poor in fresh fruits and vegetables,especially in winter,vitamin deficiencies,and frequent febrile infections in childhood).The latter part of the 19th century saw improvements in standards of living,sanitation,and diets with a corresponding decrease in rate of development of atrophic gastritis allowing duodenal ulcers to become more prominent.In the early 20th century physician’s believed they could diagnose ulcers clinically and that the diagnosis required hospitalization for"surgical disease"or for"Sippy"diets.We show that while H.pylori remained common and virulent in Europe and the United States,environmental changes resulted in changes of the pattern of gastritis producing a change in the manifestations of H.pylori infections and subsequently to a rapid decline in transmission and a rapid decline in all H.pylori-related diseases.     

Helicobacter pylori Infection in a Randomly Selected Population,Healthy Volunteers,and Patients with Gastric Ulcer and Gastric Adenocarcinoma: A Seroprevalence Study in Taiwan

To investigate the association of Helicobacter pylori and gastric ulcer and adenocarcinoma, IgG antibodies against H. pylori were examined in 823 randomly selected subjects, 92 healthy volunteers, 117 patients with gastric ulcer, and 148 with gastric adenocarcinomas in Taiwan, where the prevalence of gastric adenocarcinoma is high. The seropositivity of this population in Taiwan was 54.4%. Gastric ulcer patients had a higher seropositivity (83.8%) than healthy volunteers (62.0%) and gastric adenocarcinoma patients (62.2%) (P< 0.001). Gender difference, blood type, and habit of smoking were not associated with the seroprevalence in any study groups. Gastric ulcer coexistent with duodenal ulcer had a higher seropositivity (94.7%) (P < 0.05). The seropositivity of H. pylori in gastric adenocarcinoma patients was higher than in healthy volunteers only in younger age and was not associated with histologic type, invasion, and location of major tumors. The results reemphasize the association of H. pylori infection with gastric ulcer but not with gastric adenocarcinoma in Taiwan.     

Review: Eradication of Helicobacter pylori. Problems and recommendations

The successful isolation of Helicobacter pylori from the stomachs of patients with gastritis and peptic ulcer has revolutionized our concepts of the pathogenesis of gastritis, peptic ulcer, gastric cancer and gastric B cell lymphoma. Eradication of H. pylori heals gastritis and H. pylori-related peptic ulcer. After a successful cure of H. pylori infection, virtually no recurrence of duodenal ulcer is seen. However, treatment to cure the infection has proved difficult. Numerous clinical trials have been attempted, but as yet no ideal regimen has been identified. Monotherapies have many drawbacks and should be avoided. Dual therapies combining a proton pump inhibitor (PPI) and an antimicrobial agent provide higher eradication rates than those involving two antimicrobial agents. Bismuth-based triple therapies are more effective than dual therapies in eradicating H. pylori infection. However, poor compliance and frequent adverse effects have made these combinations less favourable in clinical practice. Proton pump inhibitor-based triple therapies have shown more consistent and higher eradication rates with a short duration of treatment, good patient compliance, fewer side effects, prompt symptom relief and fast ulcer healing. Results from PPI-based quadruple therapies are promising; however, large multicentre clinical trials are needed to confirm the effect and the complex regimen again may compromise compliance outside of the clinical trial setting. Eradication of H. pylori infection is cost-effective in the long-term management of peptic ulcer disease compared with maintenance therapy with antisecretory drugs.     

Treatment of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in Pediatrics

Opinion statement Helicobacter pylori (H. pylori) is among the most common bacterial infections in humans. In 1982, H. pylori was discovered by Marshal and Warren, demonstrating an association between H. pylori and ulcer disease. H. pylori is a gram-negative, S-shaped rod that produces enzymes like urease, catalase and oxidase. The mechanism of acquisition and transmission of H. pylori is unclear, although the most likely mode of transmission is fecaloral and oral-oral. The mode of transmission is supported by studies that demonstrate viable H. pylori organisms can be cultured from the stool or vomitus of infected patients. Risk factors such as minimal education and low socio-economic status during childhood affect the prevalence. Children infected with H. pylori develop histologic chronic active gastritis despite the fact that they are generally asymptomatic. A small percentage of these children will go on to develop peptic ulcer disease, and even gastric cancer. In contrast, the association of abdominal pain and H. pylori infection remains controversial. In the year 2000, the North American Society of Pediatric Gastroenterology guidelines on H. pylori reported that there is no evidence demonstrating a link between H. pyloriassociated gastritis and abdominal pain, except in rare cases in which gastric or duodenal ulcer disease is present. Currently, treatment with a combination of two antimicrobial agents in conjunction with a proton pump inhibitor (PPI) continues to be recommended for the treatment of H. pylori associated peptic ulcer disease.     

Circadian Gastric Acidity and Helicobacter pylori Infection in Patients with Chronic Pancreatitis

A high prevalence of duodenal ulcer has been reported in patients with chronic pancreatitis. Data from previous studies on gastric acid secretion in these patients have provided conflicting results, and the potential role of H. pylori infection has been poorly investigated. The aim of this study was to assess the circadian pattern of gastric acidity and the prevalence of H. pylori infection in a group of patients suffering from this disease. Thirty-five patients with chronic pancreatitis ascertained by means of pancreatic calcifications or ductal alterations revealed by ERCP were recruited for this prospective study. They underwent 24-hr gastric pH-metry with glass minielectrodes positioned in the gastric corpus, and their profile of gastric acidity was compared with that of 35 healthy subjects, matched for age and sex. H. pylori infection was diagnosed by means of serology. There was no statistical difference (P = NS) in gastric pH of circadian, nocturnal, daytime, and postprandial periods between healthy subjects and patients with chronic pancreatitis. The prevalence of H. pylori infection was rather low (31%) in our patients and similar to that of a comparable control population (37%) in our geographical area. In conclusion, our study shows that patients with chronic pancreatitis have a circadian pattern of gastric acidity similar to that of normal subjects. Moreover, the prevalence of H. pylori infection is low in this population. These findings greatly differentiate the ulcer diathesis in chronic pancreatitis from that of patients with ordinary duodenal ulcer and suggest that other factors are implicated in the ulcerogenic process.     

Relationship between the diversity of the cagA gene of Helicobacter pylori and gastric cancer in Okinawa, Japan

Background Helicobacter pylori CagA protein is considered to be one of the virulence factors associated with gastric cancer. CagA is injected into gastric epithelial cells, undergoes tyrosine phosphorylation, and binds to Src homology 2 domain-containing protein-tyrosine phosphatase (SHP-2). Two major subtypes of CagA have been observed in the SHP-2-binding site, the Western and East Asian types. The East Asian-type CagA binds to SHP-2 more strongly than the Western-type CagA. The diversity of CagA, which collectively determines the binding affinity of CagA to SHP-2, may be an important variable in determining the clinical outcome of infection by different H. pylori strains. Methods We investigated the relationship between the diversity of CagA and clinical outcome in Okinawa, Japan. A total 24 strains, 13 gastric cancer strains and 11 duodenal ulcer strains, were studied. We sequenced full-length cagA genes and analyzed the phylogenetic relationships between Okinawa isolates and previously characterized Western H. pylori strains. Results All isolates examined were cagA positive. The prevalence of East Asian CagA-positive strains was significantly higher in patients with gastric cancer (84.6%) than in patients with duodenal ulcer (27.3%) (χ-squared = 8.06, P = 0.011). The phylogenetic analysis showed that all gastric cancer strains with East Asian-type CagA were in the East Asian cluster, and that most duodenal ulcer strains were in the Western cluster. Conclusions The origins of H. pylori isolates are different between gastric cancer strains and duodenal ulcer strains, and East Asian CagA-positive H. pylori infection is associated with gastric cancer. The strain diversity observed in Okinawa may affect the difference in the prevalence of disease associated with H. pylori infection in Japan.     

New approaches to helicobacter pylori infection in children

Helicobacter pylori infection is usually acquired during childhood, and evidence-based guidelines regarding diagnosis and treatment of infected children have been recently published. Diseases associated with H. pylori infection are gastritis, duodenal ulcers, mucosal-associated lymphoid-type (MALT) lymphoma, and gastric adenocarcinoma. The association of specific symptoms with H. pylori infection in children and adults (ie, recurrent abdominal pain and nonulcer dyspepsia) remains controversial. Additionally, the role of H. pylor in gastroesophageal reflux disease or in extra-gastrointestinal diseases (ie, coronary artery disease) lacks sufficient evidence to demonstrate causality. The diagnosis of H. pylori-associated diseases in children can reliably be made through gastroduodenal endoscopy with biopsies. Clinical trials are underway for the validation of noninvasive diagnostic tests for the H. pylori-infected child, and current guidelines recommend eradication therapy for infected children with duodenal and gastric ulcer, gastric lymphoma, and atrophic gastritis with intestinal metaplasia. The natural history of childhood H. pylori infection is poorly described. Moreover, rational approaches to the prevention and control of childhood H. pylori infection are critically needed, requiring characterization of the determinants for acquisition and persistence and the disease outcomes following eradication.     

Prevalence of Helicobacter pylori infection in duodenal ulcer and gastro‐duodenal ulcer diseases in Taiwan

Background and Aim: The prevalence of Helicobacter pylori‐negative duodenal ulcer (DU) is increasing in Western countries but is rare in Japan. We aimed to examine the prevalence of H. pylori infection and the characteristics in DU and gastro‐duodenal ulcer (GDU) diseases in Taiwan. Study: All patients with an endoscopic diagnosis of DU or GDU from September 2003 to May 2004 at Taipei Veterans General Hospital were included. Rapid urease test was done for all patients, while urea breath test was carried out on those with negative rapid urease tests. A patient was considered infected if either test was positive. Results: The prevalence of H. pylori was 88.7% (555/626) in DU and 90.5% (95/105) in GDU patients. There was no difference in sex and prevalence of H. pylori between the two groups but age was higher in the GDU patients (60.1 ± 15.5 vs. 55.4 ± 15.5, P = 0.005). Of H. pylori‐negative DU patients, 28.2% (20/71) reported using non‐steroidal anti‐inflammatory drugs (NSAIDs)/aspirin, which were used by all 10 H. pylori‐negative GDU patients (100%) (P < 0.001). There was no difference in sex and age between H. pylori‐positive and negative DU patients. The prevalence rate of H. pylori in DU was not statistically different among outpatients, inpatients, and physical check‐up subjects (86.8% vs. 93.3% vs. 90.7%, P = 0.163). Conclusion: The prevalence of H. pylori infection in DU appears to be decreasing in Taiwan. Thus, eradication therapy without confirming the presence of H. pylori in DU patients cannot be recommended. NSAIDs/aspirin is the major risk factor for H. pylori‐negative DU patients, especially those with co‐morbid gastric ulcer.     

Effect of Helicobacter pylori Eradication on 24-Hour Gastric pH and Duodenal Gastric Metaplasia

Published data on the regression of the extent of duodenal gastric metaplasia (DGM) after the eradication of Helicobacter pylori infection and the normalization of the organism-induced alterations in gastric physiology are scanty and controversial. Therefore, we decided to assess the circadian pattern of gastric acidity and the degree of DGM before and one year after H. pylori eradication in a group of duodenal ulcer patients. Fifteen consecutive H. pylori-positive patients with endoscopically proven duodenal ulcer were recruited for this study. The diagnosis of H. pylori infection was based on CLO-test and histology, and DGM was assessed on four bulb biopsies taken before and one year after H. pylori eradication. At the same time, gastric pH was measured by 24-hr continuous intraluminal recording. H. pylori eradication was ascertained by means of concomitant negative CLO-test and histology performed both four weeks after the end of the eradicating treatment and at the one-year endoscopic control. After successful cure, all patients discontinued any antiulcer medication. The mean 24-hr gastric pH was 1.7 ± 0.4 before and 1.6 ± 0.4 after one year of H. pylori eradication (P = 0.75). DGM improved in three cases, worsened in four cases, and was unchanged in eight cases at the one-year control (P = 0.87). No correlation was found between 24-hr gastric pH and DGM (P = NS) both at baseline and one year after eradication. Our results show that neither circadian gastric acidity nor DGM change significantly one year after H. pylori eradication in duodenal ulcer patients. Thus, the disappearance of H. pylori infection does not determine any increase in gastric pH and any reversal of gastric-type epithelium in the duodenum.