Interaction of Helicobacter pylori Infection and Nonsteroidal Anti‐Inflammatory Drugs in Gastric and Duodenal Ulcers

Background: Gastric (GU) and duodenal ulcers (DU) are in most instances either induced by Helicobacter pylori infection or by nonsteroidal anti‐inflammatory drugs (NSAIDs). Whether eradication of H. pylori is beneficial in NSAID users for preventing NSAID induced GU and DU has been the focus of different studies. Materials and Methods: Mechanisms shared by both H. pylori and NSAIDs for the induction of GU and DU were reviewed and randomized controlled trials on H. pylori eradication for prevention and healing of GU and DU in patients requiring NSAID therapy were identified by a PubMed search. Results: Key factors in the induction of GU and DU for both H. pylori and NSAIDs are a decrease in pH, imbalance between apoptosis and proliferation, reduction in mucosal blood flow, and recruitment of polymorphonucleates in distinct compartments. For primary ulcer prevention, H. pylori eradication before starting an NSAID therapy reduces the risk of NSAID induced GU and virtually abolishes the risk of DU. H. pylori eradication alone is not sufficient for secondary prevention of NSAID induced GU and DU. H. pylori infection appears to further increase the protective effects of proton‐pump inhibitors (PPI) to reduce the risk of ulcer relapse. H. pylori eradication does not influence the healing of both GU and DU if NSAID intake is discontinued. Conclusions: Duodenal ulcer is more closely related to H. pylori infection than GU in NSAID users. H. pylori eradication is recommended for primary prevention of GU and DU in patients requiring NSAID therapy. PPI therapy is mandatory for secondary prevention of gastroduodenal ulcers, and appears to further reduce the risk of ulcer relapse in the presence of H. pylori.     

Decreased Prevalence of Helicobacter pylori Infection in Gastroesophageal Reflux Disease

Background.   An increased incidence of reflux esophagitis has been reported after eradication of H. pylori in patients with duodenal ulcer. To determine if H. pylori is associated with lower rates of esophagitis, we studied the prevalence of H. pylori infection in patients with and without reflux esophagitis and a subgroup of patients with concomitant peptic ulcer disease.
Methods.   Patients who underwent esophagogastroduodenoscopy and had diagnostic testing for H. pylori over a 30-month period were studied. H. pylori infection was determined by rapid urease testing, gastric histopathology, or serology. Reflux esophagitis was determined by endoscopic and/or histologic criteria.
Results.   Of 514 patients, 39.5% had H. pylori infection and 22.2% had reflux esophagitis. The prevalence of H. pylori infection in patients with reflux esophagitis was 30.7%, compared with 42.0% in patients without esophagitis ( p = 0.039). The odds ratio for esophagitis risk with H. pylori infection was 0.61 (95% CI, 0.39–0.95). Neither patient age nor gender affected H. pylori prevalence. In patients with duodenal ulcer, H. pylori was present in 36.4% of patients with esophagitis and in 69.2% of patients without esophagitis ( p = 0.018). The odds ratio for esophagitis with H. pylori infection in these patients was 0.25 (95% CI, 0.09–0.73).
Conclusions.   Our study demonstrates that H. pylori infection is significantly less prevalent in patients with reflux esophagitis and may protect against its development. In duodenal ulcer patients, this effect was more dramatic. Further study is required to confirm these findings and elucidate mechanisms underlying possible beneficial effects of H. pylori.     

Characteristics of Helicobacter pylori-induced gastritis and the effect of H. pylori eradication in patients with chronic idiopathic thrombocytopenic purpura

BACKGROUND: The association between Helicobacter pylori infection and idiopathic thrombocytopenic purpura (ITP) has been reported widely. We investigated the prevalence of H. pylori infection, its virulence profile and the effectiveness of its eradication in patients with ITP. MATERIALS AND METHODS: Twenty patients with ITP, 20 with peptic ulcer (10 gastric ulcer (GU), 10 duodenal ulcer (DU)) and 20 with NUD were studied. The virulence profile of the strains was assessed by genotyping for cagA, vacA, iceA, and hpyIIIR/hrgA and by assaying for IL-8 and DNA fragmentation after incubation with AGS cells. Infected patients and two uninfected ITP patients received triple therapy and platelets were counted before and 1 month, 6 months, 1 year, and 2 years after eradication therapy. RESULTS: H. pylori infection was found in 17 ITP (85%), 20 ulcer (100%) and 13 NUD (65%) patients. Biopsies and strains were collected from five ITP, 20 ulcer and 13 NUD patients. The ITP patients had a pangastritis or corpus-predominant gastritis pattern. All H. pylori isolates, from ITP, ulcer and NUD patients, were cagA(+) and vacA s1/m1, and did not differ in levels of IL-8 induction or DNA fragmentation. Fifteen ITP (88%) and 17 ulcer (85%) patients had successful eradication of H. pylori. Ten of these 15 (67%) H. pylori-eradicated ITP patients had platelet recovery. There was no significant change in platelet count in the two ITP patients in whom eradication failed or in the two originally H. pylori-uninfected ITP patients, or in the treated ulcer patients. Age at onset of ITP was the main determinant of platelet recovery: 100% of patients diagnosed after the age of 60 recovered compared with only 22% of those diagnosed before 50. CONCLUSIONS: H. pylori-infected ITP patients have a corpus-predominant pattern of gastritis but the virulence profile of their strains does not differ from that of ulcer or NUD patients. Eradication of H. pylori infection is a good therapeutic option for some patients with chronic ITP, especially for those who develop ITP in older age.     

Effect of Helicobacter pylori Eradication on Incidence of Gastric Cancer in Human and Animal Models: Underlying Biochemical and Molecular Events

Background:  Gastric cancer remains one of the most common cancers worldwide. A strong association exists between Helicobacter pylori infection and the risk of developing noncardia gastric cancer. H. pylori eradication by antibiotic treatment is regarded as a primary chemoprevention strategy to reduce gastric cancer incidence.
Aim:  To analyze the efficacy of H. pylori eradication in preventing gastric cancer in human and animal models, and to discuss whether biochemical, genetic, and epigenetic changes associated with H. pylori infection are reversible after curing the infection.
Results:  Several intervention trials have indicated that in some patients, H. pylori eradication leads to regression and prevents the progression of precancerous lesions. The eradication therapy reduces gastric cancer incidence in patients without any precancerous lesions at the baseline and is most effective before the development of atrophic gastritis. A few recent intervention studies in Japan have demonstrated significant prophylactic effects of eradication therapy on the development of gastric cancer, suggesting the use of eradication therapy in high-risk populations as a gastric cancer reduction strategy. However, gastric cancer may still develop despite successful eradication therapy. Studies in animal models have confirmed the use of eradication therapy at an early point of infection to prevent gastric cancer development.
Conclusion:  H. pylori eradication may not completely abolish the risk of gastric cancer. However, eradication therapy may be used in high-risk populations to reduce gastric cancer incidence. It can reverse many biochemical, genetic, and epigenetic changes that H. pylori infection induces in the stomach.     

Genetic Variation in a4GnT in Relation to Helicobacter pylori Serology and Gastric Cancer Risk

Background:  Helicobacter pylori, a known risk factor of gastric cancer, rarely colonize the deeper portion of normal gastric glands, where the mucus is rich in α-1,4-linked N -acetylglucosamine capped O -glycans, that strongly inhibit H. pylori growth in vitro .
Materials and methods:  We investigated the association between genetic variation in the O -glycan transferase encoding gene ( a4GnT ) and H. pylori infection and gastric cancer risk using a Polish population-based case–control study (273 gastric cancer patients and 377 controls).
Results:  A haplotype at the rs2622694–rs397266 locus was associated with H. pylori infection, with the A-A haplotype associated with a higher risk compared with the most frequent G-G haplotype (odds ratio 2.30; 95% confidence interval 1.35–3.92). The association remained significant after correction for multiple tests (global p value: nominal 0.002, empirical 0.045). Neither this haplotype nor the tagSNPs were associated with overall gastric cancer risk.
Conclusion:  a4GnT genetic variation may be relevant to H. pylori infection, but not to gastric cancer risk.     

Helicobacter pylori Reinfection in Brazilian Patients with Peptic Ulcer Disease: A 5-Year Follow-Up

Background:  The Helicobacter pylori reinfection seems to be higher in developing countries, than in developed ones. The aim of the study was to determine the annual recurrence rate of H. pylori , in Brazilian patients with peptic ulcer disease, in a 5-year follow-up.
Methods:  Patients, with peptic ulcer disease diagnosed by upper digestive endoscopy (UDE) and H. pylori infection verified by histological analysis, rapid urease test, polymerase chain reaction, and urea breath test (UBT), were treated for bacterial eradication. The cure of the infection was verified using the same tests, 3 months after. Clinical evaluation and UBT were performed after sixth and ninth month. After 1 year of follow-up, UBT and UDE were repeated. Up to the fifth year, patients were assessed twice a year and an UBT was performed annually. The patients included and all the reinfected were tested for 15 different genes of the H. pylori .
Results:  One hundred and forty-seven patients were followed: 19 for 1 year, eight for 2 years, four for 3 years, five for 4 years, and 98 for 5 years, totaling 557 patients/years. Recurrence did not occur in the first year. In the second year, two patients were reinfected; in the third, four patients; in the fourth, three patients; and in the fifth, one patient. The total of reinfected patients was 10. The annual reinfection rate was 1.8%.
Conclusion:  Brazil presents a low prevalence of H. pylori reinfection, similar to the developed countries.     

CagA and VacA: Virulence Factors of Helicobacter pylori in Thai patients with Gastroduodenal Diseases

Background. The aim of this study was to assess the seroprevalence of cytotoxin-associated gene A ( cag A) and vacuolating cytotoxin gene A ( vac A) of Helicobacter pylori in selected Thai populations with specific gastroduodenal diseases.
Materials and Methods. The immunoblot assay was used to detect serum antibodies against CagA and VacA obtained from the following patients: 87 cases of nonulcer dyspepsia (NUD), 61 cases of duodenal ulcer (DU), 49 cases of gastric ulcer (GU), and 10 cases of gastric cancer (GC).
Results. Serum antibodies to CagA were detected in 75.4% of all patients (70.1% of NUD, 78.7% of DU, 77.6% of GU, and 90% of GC). Although the prevalence of CagA seropositivity in GC patients was higher than in the other three groups, the difference was not statistically significant ( p > .05).
Conclusions. The high seroprevalence of the CagA-positive H. pylori strain in patients with peptic ulcer, GC, and NUD indicates that this strain is common in Thai patients with gastroduodenal diseases. Furthermore, phenotypic classification of H. pylori into type 1 (CagA-positive, VacA-positive) and type 2 (CagA-negative, VacA-negative) is not a useful marker for screening patients with severe forms of gastroduodenal diseases.     

Helicobacter pylori Infection, Gastritis, and the Temperature of Choice for Hot Drinks

Background. The role of the temperature of the diet as a potential etiological factor for gastritis or peptic ulcer disease has been postulated since the beginning of the century. Animal studies have demonstrated damage to gastric mucosa caused by hot water at 60 to 80°C. In the pre- Helicobacter pylori era it was reported that the majority of ulcer patients preferred hot drinks. It also was reported that the temperature of choice for drinks increased with severity of histological grade of gastritis. We evaluated the association between the preferred temperature of hot drinks and the presence of H. pylori infection.
Methods. We tested the temperature of choice for hot drinking liquids among 12 H. pylori -negative and 43 H. pylori -positive volunteers. We also compared the effect of H. pylori therapy on hot drink temperature preference and, in 32 individuals, whether there was a relation between temperature and the degree of gastric atrophy.
Results. There was no difference in the preferred temperature for hot drinks between those volunteers with and without H. pylori infection (63.4°± 6°C compared to 61.3°± 7°C, respectively) (mean ± 1 SD, p =.3) There was no change in preferred temperature after successful therapy of the H. pylori infection compared to unsuccessful H. pylori therapy, nor was there a correlation between the preferred temperature and the presence, absence, or degree of gastric atrophy ( r ² < 0.001).
Conclusion. The temperature of preference for hot drinks was not influenced by H. pylori infection or by the presence of atrophic gastritis.     

Curing Helicobacter pylori infection in patients with duodenal ulcer does not provoke gastroesophageal reflux disease

Background. It has been suggested that the incidence of gastroesophageal reflux disease (GERD) increases after successful eradication of Helicobacter pylori infection. We present data on development of GERD from a controlled study of H. pylori eradication in 165 duodenal ulcer patients.
Methods. Patients (mean age, 55 years; 102 men; current smokers; n = 74) were randomly assigned 2 : 1 to receive omeprazole, 40 mg twice daily, in combination with either amoxicillin, 750 mg twice daily, or placebo. Endoscopy and dyspeptic symptoms, including heartburn, were assessed at inclusion and at 6, 12, and 24 months after treatment. In addition, symptoms were assessed at 18 months. Patients with erosive esophagitis or reflux symptoms requiring treatment at inclusion were not included in the study.
Results. Fifty-one of 145 (35%) evaluable patients developed heartburn, and 13 of 145 (9%) developed esophagitis during follow-up. The life-table analysis of the cumulated risk of developing heartburn showed that patients whose H. pylori infection was eradicated had a significantly lower risk for developing heartburn than those with persistent H. pylori infection. The groups did not show any difference in cumulative risk of developing esophagitis.
Conclusion. Our data show that successful eradication of H. pylori infection does not increase the incidence of GERD in duodenal ulcer patients.     

Antigenic Mimicry Between Helicobacter pylori and Gastric Mucosa: Failure to Implicate Heat-Shock Protein Hsp60 Using Immunoelectron Microscopy

Background. Helicobacter pylori infection induces autoantibodies that cross-react with human gastric mucosa from infected individuals. Candidates for the antigens responsible for molecular mimicry causing autoreactivity include the heat-shock protein HspB (Hsp60, sometimes called Hsp54) or Lewis x and Lewis y carbohydrate antigens.
Objective. Our goal was to investigate the involvement of HspB (Hsp60) in autoreactivity between H. pylori and gastric biopsy tissue.
Materials and Methods. Immunoelectron microscopy was used to study cross-reactivity among biopsy tissues from a patient with gastritis, gastric ulcer, and duodenal ulcer and his own serum as well as reactivity with serum raised against HspB from H. pylori and monoclonal antibodies against Lewis antigens.
Results. The patient serum reacted with gastric mucosa, and the antibodies involved were predominantly IgG. Antibody raised to H. pylori HspB (Hsp60) reacted only with H. pylori cells but not with gastric mucosal tissue. In contrast, monoclonal antibodies specific for Lewis x and Lewis y antigens reacted with both H. pylori and human gastric epithelial tissue.
Conclusions. Hsp60 (Hsp54) is unlikely to be involved in autoreactivity seen in individuals infected with H. pylori. In contrast, we could not rule out the role of Lewis x and Lewis y carbohydrate antigens, expressed as a component of H. pylori lipopolysaccharides, in molecular mimicry and autoantibody production.     

Effect of Helicobacter pylori eradication on peptic ulcer disease complicated with outlet obstruction

Background. At present, the prevalence of Helicobacter pylori ( H. pylori ) in complicated peptic ulcer and the effect of H. pylori eradication on complicated peptic ulcer have not been fully established. In this study, we report the prevalence of H. pylori in peptic ulcer patients complicated with gastric outlet obstruction, effectiveness of oral eradication therapy on these patients, and their long-term follow up.
Patients and Methods. Ten consecutive patients presenting with clinically and endoscopically significant obstructed peptic ulcers were included in this study. During each endoscopy, seven gastric biopsy specimens were obtained and analyzed for H. pylori colonization.
Results. The antral mucosal biopsy specimens were positive for H. pylori in nine patients. H. pylori infection was eradicated and complete ulcer healing was observed in all patients. The mean follow-up period was 14 (7–24) months. One patient had duodenal perforation and underwent surgical intervention following medical treatment, despite the eradication of H. pylori. Ulcer recurrence was noted in two (22.2%) of nine patients, and in one of them the recurrent ulcer was complicated with obstruction (11.1%). The mean time to ulcer recurrence was 17 months (range, 10–24 months). The biopsies and CLOtests were H. pylori negative at the time of ulcer or erosion recurrence in two patients.
Conclusion. We suggest that H. pylori eradication may improve the resolution in obstructive ulcer cases with colonization.     

An Alternative Non-Macrolide, Non-Imidazole Treatment Regimen for Curing Helicobacter pylori and Duodenal Ulcers: Ranitidine Bismuth Citrate Plus Amoxicillin

Background. Because patients who fail to be cured of H. pylori infection following macrolide or imidazole therapy are difficult to treat, there is a clear need for a reasonably effective and simple second-line treatment regimen. The purpose of these two studies was to evaluate the efficacy of ranitidine bismuth citrate (RBC) plus amoxicillin for the cure of H. pylori infection and for healing duodenal ulcers and preventing ulcer relapse.
Materials and Methods. Two identically designed randomized, double-blind, double-dummy studies were conducted in patients with an H. pylori -associated duodenal ulcer. Patients were treated with either RBC 400 mg bid for 4 weeks plus amoxicillin 500 mg qid for 2 weeks, RBC 400 mg bid for 4 weeks and placebo qid for 2 weeks, placebo bid for 4 weeks and amoxicillin 500 mg qid for 2 weeks, or placebo bid for 4 weeks and placebo qid for 2 weeks. Patients with healed ulcers after 4 weeks of treatment were eligible for entry into a 24-week observation phase for the assessment of H. pylori status (culture, histology, and CLOtest^TM) and ulcer relapse.
Results. A total of 229 patients with confirmed H. pylori infection at baseline were evaluated. Of these, 132 whose ulcers had healed entered the 24-week posttreatment observation phase. The combination of RBC plus amoxicillin resulted in higher H. pylori cure rates (55%) and higher duodenal ulcer healing (74%) than did either treatment alone. All treatments were well tolerated.
Conclusions. The combination of ranitidine bismuth citrate plus amoxicillin cures H. pylori infection in more than half of the patients treated. This treatment regimen shows promise as the basis for future non-macrolide, non-imidazole triple therapy regimens for curing H. pylori infection. Such regimens may be appropriate second-line treatment for patients who are resistant to or who are unable to tolerate macrolide- or imidazole-containing therapies.     

Double-Blind, Multicenter Evaluation of Lansoprazole and Amoxicillin Dual Therapy for the Cure of Helicobacter pylori Infection

Background Treatment with amoxicillin plus omeprazole results in disappointing cure rates of Helicobacter pylori infection. The minimal inhibitory concentration of lansoprazole for H. pylori in vitro is lower than that for omeprazole, prompting interest in treatment with amoxicillin plus lansoprazole.
Materials and Methods. H. pylori -infected patients with endoscopically documented duodenal ulcer either currently or within the past year were randomized to 14 days of (1) lansoprazole, 30 mg bid, plus amoxicillin, 1 gm tid; (2) lansoprazole, 30 mg tid, plus amoxicillin, 1 gm tid; (3) lansoprazole, 30 mg tid alone; or (4) amoxicillin, 1 gm tid alone. Endoscopy was done at enrollment and at 4 to 6 weeks after completion of treatment or for recurrent symptoms. H. pylori status was assessed by culture and histology. Ulcer prevalence was evaluated at follow-up endoscopy.
Results. Two hundred sixty-two patients met enrollment criteria and were treated. By per-protocol analysis, H. pylori infection was cured in 57% of those treated with lansoprazole twice daily plus amoxicillin and in 67% of those treated with lansoprazole three times daily plus amoxicillin, compared with 0% treated with lansoprazole alone or amoxicillin alone ( p < .001 for dual therapy versus either monotherapy). Amoxicillin resistance was not observed. At follow-up endoscopy, ulcer prevalence was 17% in patients treated with lansoprazole twice daily plus amoxicillin, 23% in those treated with lansoprazole three times daily plus amoxicillin, 33% in those treated with lansoprazole alone, and 35% in those treated with amoxicillin alone ( p = .024; lansoprazole twice daily plus amoxicillin versus amoxicillin alone).
Conclusions. Treatment with amoxicillin plus lansoprazole, 30 mg tid, led to cure of H. pylori infection in 67% of patients with active or recently healed duodenal ulcer.     

Helicobacter pylori and Non-malignant Diseases

It is well known that Helicobacter pylori infection is associated with many nonmalignant disorders such as gastritis, peptic ulcer, gastroesophageal reflux disease (GERD), gastric polyp, nonsteroidal anti-inflammatory drug (NSAID)/aspirin-induced gastric injury, and functional dyspepsia. In 2008, interesting articles on the association of H. pylori infection with these disorders were presented, some of which intended to reveal the mechanisms of inter-individual differences in response to H. pylori infection, and have demonstrated that genetic differences in host and bacterial factors as well as environmental factors account for these differences. A decline in the occurrence of peptic ulcer related to H. pylori was confirmed. An inverse relationship between H. pylori infection and GERD was also confirmed but the impact of gastric atrophy on the prevention of GERD remained debatable. For NSAID-induced gastric injury, eradication of H. pylori infection has been recommended. During this year, eradication of H. pylori infection was recommended for patients treated with antiplatelet therapy as well as aspirin and NSAID. It was also reported that for patients with functional dyspepsia, eradication of H. pylori offers a modest but significant benefit.     

Negative association between Helicobacter pylori infection and reflux esophagitis in older patients: case-control study in Japan

Background. Recent studies have clarified a close association between H. pylori infection and gastritis, peptic ulcer disease, and gastric cancer, but there is little information concerning the relationship between H. pylori infection and reflux esophagitis (RE). We investigated the relationship between H. pylori , RE, and corpus gastritis.
Subjects and Methods. Ninety-five patients with RE and 190 sex- and age-matched asymptomatic healthy controls demonstrating no localized lesions in the upper GI tract were studied and evaluated for H. pylori infection, histologic gastritis, serum gastrin, and pepsinogens (PGs).
Results. H. pylori infection was significantly lower in RE patients than in asymptomatic controls (41% vs. 76%, p < .01). Histologic gastritis of both the antrum and corpus was significantly less frequent (antrum; p < .01, corpus; p < .01), and serum levels of PGI and the PG I/II ratio were significantly higher in RE patients than in controls (PGI; p < .05, PG I/II ratio; p < .01). When the subjects were divided into two age groups (59 years of age and younger and 60 years of age and older), a significant difference was found only among patients over 60 years of age (29% vs. 85%, p < .01). Among subjects in this age group, gastritis in both the antrum and corpus were significantly milder in RE patients than in controls. Although the prevalence of H. pylori infection was similar between the two groups of patients under 59 years of age, corpus gastritis was significantly milder in patients than in controls ( p < .05).
Conclusions. A significantly low prevalence of H. pylori infection was found in RE patients over 60 years of age but not in those under 59 in comparison with sex- and age-matched controls. The relative lack of corpus gastritis might play a role in the pathogenesis of RE in our population through preservation of the acid secretion area.     

Helicobacter pylori infection as a cause of gastritis,duodenal ulcer,gastric cancer and nonulcer dyspepsia: a systematic overview.

OBJECTIVE: To evaluate current evidence for a causal relation between Helicobacter pylori infection and gastritis, duodenal ulcer, gastric cancer and nonulcer dyspepsia. DATA SOURCES: A MEDLINE search for articles published in English between January 1983 and December 1992 with the use of MeSH terms Helicobacter pylori, gastritis, duodenal ulcer, gastric cancer, dyspepsia and clinical trial; abstracts were excluded. Six journals and Current Contents were searched manually for pertinent articles published in that time frame. STUDY SELECTION: Original studies with at least 25 patients, case reports and reviews that examined the relation between H. pylori and the four gastrointestinal disorders; 350 articles were on gastritis, 122 on duodenal ulcer, 44 on gastric cancer and 96 on nonulcer dyspepsia. DATA EXTRACTION: The quality of the studies was rated independently on a four-point scale. The strength of the evidence was assessed using a six-point scale for each of the eight established guidelines for determining a causal relation. DATA SYNTHESIS: There was conclusive evidence of a causal relation between H. pylori infection and histologic gastritis. Koch''s postulates for the identification of a microorganism as the causative agent of a disease were fulfilled for H. pylori as a causative agent of gastritis. There was strong evidence that H. pylori is the main cause of duodenal ulcers not induced by nonsteroidal anti-inflammatory drugs, but all of Koch''s postulates were not fulfilled. There was moderate epidemiologic evidence of an association between chronic H. pylori infection and gastric cancer. There was a lack of convincing evidence of a causal association between H. pylori and nonulcer dyspepsia. CONCLUSIONS: The evidence supports a strong causal relation between H. pylori infection and gastritis and duodenal ulcer and a moderate relation between such infection and gastric cancer. Further studies are needed to clarify the role of H. pylori in these disorders. Thus far, there is no evidence of a causal relation between H. pylori and nonulcer dyspepsia.     

Helicobacter and Gastric Malignancies

Individuals infected with Helicobacter pylori , a stomach colonizing bacteria, have an increased risk of developing gastric malignancies. The risk for developing cancer relates to the physiologic and histologic changes that H. pylori infection induces in the stomach. In the last year numerous studies have been conducted in order to characterize the association between H. pylori infection and gastric cancer. These studies range from epidemiologic approaches aiming at the identification of environmental, host genetic, and bacterial factors associated with risk of gastric cancer, to molecular and cell biology approaches aiming at understanding the interaction between H. pylori and the transforming epithelial cell. In this review an account of the last year's research activity on the relationship between H. pylori and gastric cancer will be given.     

Similarities and gradients in growth unit branching patterns during ontogeny in "Fuji" apple trees: a stochastic approach

This study aims to explore and model the changes in growth unit (GU) branching patterns during tree ontogeny. The question was addressed in apple trees cv. "Fuji", by analysing the relative impact of GU length and within-tree position. The development of two 6-year-old trees was recorded over 6 years. The fate of axillary buds along each GU was represented as a sequence of symbols corresponding to five types of lateral growth: latent buds, short, medium, long, and floral lateral GUs. Based on an exploratory analysis of data and a priori hypotheses, a hidden semi-Markov chain was estimated from all of these GU sequences. This model was composed of six transient states representing successive branching zones along the GUs. The accuracy of this global model was a posteriori assessed by fitting the characteristic distributions computed from model parameters to the corresponding empirical characteristic distributions extracted from the observed sequences. The observed sequences were then grouped hierarchically according to the GU length, year of growth, and branching order. Comparing model parameters between these sub-groups revealed similarities between GUs. These similarities were based on particular branching zones whose composition and relative position within the GUs remained invariant across the subgroups: the latent zones, floral zone, and short-lateral zone. The probability of occurrence of the floral zone varied with the year, showing the alternate fruiting of "Fuji". It is shown that, during tree ontogeny, as GU length decreases, branching patterns tend to progressively simplify due to the disappearance of the most central zones and a progressive reduction in the length of the floral zone.     

Effect of Helicobacter pylori eradication on extent of duodenal gastric metaplasia and grade of gastritis

The extent of the regression of duodenal gastric metaplasia (DGM) after the eradication of Helicobacter pylori infection is controversial. Therefore, we decided to assess the degree of DGM before, sex weeks and one year after H. pylori eradication. 105 consecutive Helicobacter pylori positive patients with endoscopically proven duodenal ulcer, with DGM and Helicobacter pylori infection were recruited for this study. The diagnosis of Helicobacter pylori infection was based on CLO-test and histology, and DGM was assessed on four bulb biopsies taken before, sex weeks and one year after Helicobacter pylori eradication. Histological assessment of Helicobacter pylori associated gastritis was performed according to the Sydney classification. Follow up study on 98 patients before, six weeks and one year after the eradication of Helicobacter pylori showed that the mean extent of DGM did not change significantly after eradication and did not differ when compared with 14 patients with persisting infection. Our results show that the inflammatory process related to Helicobacter pylori does not play the main role in the development of DGM.