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PubMedDate not supplied

Helicobacter pylori and pre-neoplastic and neoplastic gastric lesions.

The spiral bacterium Helicobacter pylori has gained increasing interest as an important gastroduodenal pathogen since its isolation from the gastric mucosa. The presence of Helicobacter pylori in the human stomach is closely associated with chronic gastric inflammatory disease and growing evidence suggests an aetiologic role of this organism in peptic disease. Moreover, epidemiological and histological studies suggest that Helicobacter pylori may be a risk factor for gastric carcinoma and primary gastric lymphoma. Evidence supporting the role of Helicobacter pylori in the pathogenesis of pre-cancerous lesions are reviewed here.

Helicobacter pylori↗
PubMedDate not supplied

Validation of a new serologic test for the detection of Helicobacter pylori.

In order to determine normal ranges for positive and negative titres using a new commercially available second generation serologic ELISA test for the detection of Helicobacter pylori IgG antibodies (Malakit by Biolab, Limal, Belgium) we investigated 560 asymptomatic pregnant women aged 20 to 44. 128 patients (22.9%) had a positive titre for Helicobacter pylori. Although we were able to observe an increase of the number of seropositive subjects with advancing age, a significant increase in titre with age, both for positive and negative titres, could not be demonstrated. Although there was a much higher prevalence of Helicobacter pylori seropositivity in patients with a non-caucasian ethnic background, we did not observe a significant difference in cut-off limit between the different ethnic populations. In all seropositive patients a control serology and 13C-urea breath test were performed 4 to 6 months later. In 124 patients (96.9%) both control examinations were positive. The positivity of the 13C-urea breath test suggests an existent Helicobacter pylori infection in these (symptom-free) women. 13C-urea breath tests were also performed in 100 randomly selected seronegative women and were all negative, as well. Since 13C-urea breath tests were positive in seropositive subjects and negative in seronegative women, we validated the manufacturer's previously established cut-off values, based on only 37 adult patients, in a much larger population.

Adult↗
PubMed1993

[Mucinase activity of Helicobacter pylori: application of simplified mucinase test].

We conducted the simplified mucinase tests about Helicobacters (Helicobacter pylori, Helicobacter felis and Helicobacter mustelae) and Campylobacter jejuni, positive controls were Pseudomonas maltophilia and Pseudomonas cepacia. H. pylori, H. felis and C. jejuni showed low resolution activities for hog gastric mucin, however H. mustelae had no detectable the activities. This enzymatic activity varies considerably by cultural condition of H. pylori, therefore it is difficult to compare the activity about each strain. This simplified mucinase test proved that H. pylori has some adverse effect on gastric mucin.

Animals↗
PubMed1996

[Prospective study of erradication of Helicobacter pylori in patients with duodenal ulcer: analysis of antral and gastric body biopsies].

Omeprazole may not eradicate Helicobacter pylori from the stomach but rather displace it from the antrum to the stomach body. This fact could interfere with colonization studies in patients receiving the drug. The aim of this study was to assess the presence of Helicobacter pylori, defined as a positive urease test, culture or microscopical examination, in antral and gastric body biopsies in patients receiving treatment with omeprazole. Sixty four paired antral and gastric body biopsies obtained at the end of a 28 day course of omeprazole, 62 obtained four months later, 40 obtained eight months later and 23 obtained 12 months later were analyzed. There was a 92% concordance between antral and gastric body biopsies for the presence of Helicobacter pylori. However, nine of the samples obtained at 28 days (14%) were negative for H pylori in the antrum but positive in the gastric body. It is concluded that for early assessment of Helicobacter pylori eradication after omeprazole treatment, paired biopsies of antrum and gastric body are needed.

Duodenal Ulcer↗
PubMed1997

[Isolation of Helicobacter pylori: necessity of control of transport conditions].

The aim of the study was the influence of transport conditions of antrum biopsies on the diagnostis of Helicobacter pylori infection by mean of bacteriological methods. We compare bacteriological to anatomopathological methods of Helicobacter pylori infection during two periods which differed by the transport conditions for antrum biopsies. During the first period (P1), 57 specimens were carried to the laboratory at room temperature and physiological serum immersion was inconstant. During the second period (P2), 56 specimens were all correctly immerged into 5 ml of physiological serum, in a 15 mm diameter tube which was vertically maintained in ice. Anatomopathological methods were considered as the reference method for the diagnostic of Helicobacter pylori infection. The sensibility of bacteriological culture was increased from 59% (P1) to 84% (P2) (p < 0.05) when specificity was unchanged. Furthermore sensibility of bacteriological direct examination was increased from 41% (P1) to 61% (P2). Complete biopsy immersion and ice transport of samples appear as necessary conditions for the optimal diagnostic of Helicobacter infections by mean of bacteriological methods.

Bacteriological Techniques↗
PubMed1997

[Helicobacter infections of man and of domestic carnivores: comparative data].

The role of Helicobacter pylori in generating of the chronic gastritis and in the maintaining of the gastroduodenal ulcerous disease, has been a major medical discovery of these past years in human gastroenterology. More recently in Man, studies have showed that the gastric tumours (adenocarcinoma, lymphoma) are epidemiologically associated with the H. pylori infection. Although the H. pylori infection is the one of the most frequent in the word, the epidemiologic and ecologic aspects of this infections are still not very well known. Thanks to phylogenic studies using the new molecular biology techniques and to fundamental experimental studies, we know more about helicobacteria in domestic carnivores as well as their morphologic characteristic, their taxonomia and more importantly details concerning their ecological niche. Few clinical studies have been made to this day, but the ones that have been undertaken are interesting in confirming the extensive prevalence of Helicobacter infections in domestic carnivores and in underlining their role in the genesis of the inflammatory gastropathies observed in these species. Recent observations have demonstrated the ubiquitous character of these helicobacteria by showing their presence in the stomach of man, dogs and cats. This ubiquitous character has led some scientists to consider the potential zoonotic risk of the human infection by Helicobacter heilmannii, felis or pylori. Finally, the Helicobacter infection of animals seems to be an interesting model not only in the study of the affections caused by these bacteria, but also in the elaboration of a future vaccine against the H. pylori infection in man.

Animals↗
PubMed1996

Helicobacter pylori in recently-diagnosed versus chronic duodenal ulcer.

Helicobacter pylori is one of the main causes of type B gastritis and is frequently found in the gastric antrum or in areas of gastric metaplasia in duodenal ulcer patients. The aim of this study was to evaluate Helicobacter pylori and gastric metaplasia prevalence in duodenal ulcer patients within their first diagnosed episode compared to those with chronic ulcer disease. Eighty three patients were prospectively studied in a 2-year period, they were divided into 3 groups: Group I, control, included 29 patients; Group II, 17 patients, included patients with first diagnosed duodenal ulcer episode; and Group III, 37 patients, with chronic ulcer disease. Helicobacter pylori prevalence in duodenum was significatively lower in Group II versus Group III and controls (67.5%, 0% and 3.2% respectively) (p < 0.001). In the antrum Hp prevalence was also lower in Group II compared to Group III and I (41%, 78.3% and 24.1%) with a significative difference (p < 0.001). Gastric metaplasia was significantly higher in Group III versus Group II and controls. These results suggest that Helicobacter pylori plays an important but not exclusive role in the pathogenesis of these disease together with other factors.

Adult↗
PubMed1998

Use of a [13C]urea breath test for detection of gastric infection with Helicobacter spp in dogs.

OBJECTIVE: To evaluate a [13C]urea breath and blood test (UBBT) for detection of gastric infections with Helicobacter spp in dogs. ANIMALS: 8 Beagles with, and 3 Beagles without, gastric Helicobacter spp infection. PROCEDURE: The UBBT was evaluated in dogs of known infection status before and after treatment with amoxicillin, metronidazole, and famotidine (AMF). A standard dose of [13C]urea (4 mg/kg of body weight) was given, and breath and blood samples were obtained at 0, 20, 40, and 60 minutes after administration. Effect of AMF treatment on breath and blood 13CO2 values, gastric urease activity (GUA), and gastric spiral organisms (GSO) was evaluated 3 to 4 and 28 to 29 days after 14 days of AMF treatment. RESULTS: Breath and blood 13CO2 values were higher in infected dogs than uninfected dogs. Endogenous 13CO2 production was minimal. Breath and blood 13CO2 values varied by 10 and 13%, respectively, between test periods. There was a correlation (R2 = 0.985) between breath and blood 13CO2 values. In 6 of 8 infected dogs, these values were decreased 3 days after completion of AMF administration and biopsy specimens lacked GSO and GUA . For these 6 dogs, breath and blood 13CO2 values were variable 28 days after completion of AMF treatment, and were associated with recurrence of GSO in 6 dogs and GUA in 4 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study indicate that UBBT may provide a noninvasive procedure for detection of gastric infections with Helicobacter spp in dogs. Treatment with amoxicillin, metronidazole, and famotidine may not be effective in eradicating gastric infections with Helicobacter spp in dogs.

Amoxicillin↗
PubMed2005

Mast cells are critical mediators of vaccine-induced Helicobacter clearance in the mouse model.

BACKGROUND & AIMS: Despite the proven ability of immunization to prevent Helicobacter infection in mouse models, the precise mechanism of protection has remained elusive. METHODS: We explored the cellular events associated with Helicobacter clearance from the stomach following vaccination by flow cytometry analysis and histological and molecular studies. RESULTS: Kinetic studies showed that the infection is undetectable in vaccinated mice at day 5 postbacterial challenge. Flow cytometry analysis showed that the percentages of mast cells (CD3 - CD117 + ) increased in the lymphoid cells isolated from the stomach at day 4 postchallenge in urease + cholera toxin (CT)-vaccinated mice in comparison with mice administered with CT alone (9.4% +/- 4.4% and 3.1% +/- 1%, respectively, for vaccinated and CT administered, n = 5; P < .01). Quantitative PCR analysis showed an increased messenger RNA (mRNA) expression of the mast cell proteases 1 and 2 at day 5 postchallenge in the stomach of vaccinated mice. In contrast to wild-type mice, mast cell-deficient mice (W/W v mice) were not protected from H felis colonization after vaccination. Indeed only 1 out of 12 vaccinated W/W v mice showed a negative urease test. Remarkably, vaccinated W/W v mice reconstituted with cultured bone marrow-derived mast cells recovered the ability to clear the infection after vaccination (8 out of 10 mast cell-reconstituted mice showed negative urease tests [ P < .006 as compared with wild-type mice]). CONCLUSIONS: These experiments show that mast cells are, unexpectedly, critical mediators of anti- Helicobacter vaccination.

Administration, Intranasal↗
PubMed1999

Qualitative and quantitative analysis of the local and systemic antibody response in mice and humans with Helicobacter immunity and infection.

Immunization can prevent or cure an otherwise chronic gastric Helicobacter infection in several different animal models. The goal of the present study was to compare the titers and specificities of local and systemic antibody responses generated by Helicobacter infection and immunization. Protective immunization results in levels of specific gastric antibody significantly lower than induced by infection. However, antibodies from protectively immunized mice preferentially recognize immunodominant proteins of 10-22 and 30 kDa. Immunoblot analysis of infected mice and humans demonstrated that the serum IgA, but not serum IgG, binding profiles yield an accurate profile of the antigenic specificity of the host's gastric IgA. Therefore, serum IgA may be useful in evaluating the immunodominant antigens at the gastric mucosa of infected persons and possibly in determining the immunogenicity of orally applied Helicobacter vaccines.

Adult↗
PubMed2001

Protective anti-Helicobacter immunity is induced with aluminum hydroxide or complete Freund's adjuvant by systemic immunization.

To determine whether systemic immunization against Helicobacter pylori could be achieved with an adjuvant approved for human use, the efficacy of vaccination with Helicobacter antigen in combination with aluminum hydroxide (AlOH) was evaluated in a murine model of Helicobacter infection. Immunization with antigen and AlOH induced interleukin-5-secreting, antigen-specific T cells, and immunization with antigen and complete Freund's adjuvant induced interferon-gamma-secreting, antigen-specific T cells, as determined by ELISPOT assay. Both immune responses conferred protection after challenge with either H. pylori or H. felis, as confirmed by the complete absence of any bacteria, as assessed by both histology and culture of gastric biopsy samples. Protection was antibody independent, as demonstrated with antibody-deficient muMT mice (immunoglobulin-gene knockout mice), and CD4(+) spleen T cells from immunized mice were sufficient to transfer protective immunity to otherwise immunodeficient rag1(-/-) recipients. These results suggest an alternative and potentially more expeditious strategy for development of a human-use H. pylori vaccine.

Adoptive Transfer↗
PubMed2006

Helicobacter and digestive malignancies.

Important new data were published during the past year on the relationship of Helicobacter infection and gastric neoplasias. In the pathogenesis of gastric cancer, a thrilling new hypothesis was put forward based on animal experiments. Helicobacter infection induces gastric mucosal damage and bone marrow-derived cells (mobilized into peripheral blood and attracted to the inflamed mucosa) replace the areas of damaged gastric tissue and turn into neoplastic proliferation. Several studies focused on mechanisms related to the development of gastric malignancy in infected individuals with particular attention to inflammatory cytokine gene polymorphisms. Some new evidence is also reported to suggest that Helicobacter infection increases the risk of neoplasias outside the stomach in the liver and colon.

Animals↗
PubMed1994

Lack of protection against gastric Helicobacter infection following immunisation with jack bean urease: the rejection of a novel hypothesis.

The common mucosal immune system was stimulated by oral immunisation with jack bean urease and the adjuvant cholera toxin. A high level of local antibody and serum antibody was induced in mice following hyperimmunisation with this combination. No cross-reacting antibody was found against either Helicobacter pylori or Helicobacter felis. No protection was observed against oral challenge of immunised mice with living H. felis thus disproving the interesting hypothesis of Pallen and Clayton that plant urease might induce a protective immunity against helicobacter infection.

Animals↗
PubMed2002

Putative effect of Helicobacter pylori and gastritis on gastric acid secretion in cat.

Helicobacter pylori may increase or inhibit gastric acid. We studied acid variations and plasma gastrin in cats harboring Helicobacter felis, harboring H. pylori, or free of gastric pathogens with reference to thioperamide (H(3) receptor antagonist) and SR-27417A (PAF receptor antagonist). In cats harboring H. felis, gastric mucosa were histologically normal. After H. felis eradication, pentagastrin-stimulated acid secretion was increased (40%) compared with the situation before eradication. Thioperamide abolished this inhibitory effect of H. felis, whereas SR-27417A did not. Basal and meal-stimulated plasma gastrin levels were not affected by eradication therapy. Acid secretion was inhibited (-80%) in week 3, increased from weeks 5 to 9, and remained constant for up to 42 weeks after H. pylori infection. SR-27417A had no effect on acid secretion before week 8 but inhibited it thereafter, and thioperamide increased it (20%) only before week 7 in those cats. Helicobacter inhibits gastric acid via an H(3) receptor pathway. Inflammatory mediators are thus involved in adaptation to the inhibitory effects of H. pylori on acid secretion.

Animals↗
PubMed2006

Who ate whom? Adaptive Helicobacter genomic changes that accompanied a host jump from early humans to large felines.

Helicobacter pylori infection of humans is so old that its population genetic structure reflects that of ancient human migrations. A closely related species, Helicobacter acinonychis, is specific for large felines, including cheetahs, lions, and tigers, whereas hosts more closely related to humans harbor more distantly related Helicobacter species. This observation suggests a jump between host species. But who ate whom and when did it happen? In order to resolve this question, we determined the genomic sequence of H. acinonychis strain Sheeba and compared it to genomes from H. pylori. The conserved core genes between the genomes are so similar that the host jump probably occurred within the last 200,000 (range 50,000-400,000) years. However, the Sheeba genome also possesses unique features that indicate the direction of the host jump, namely from early humans to cats. Sheeba possesses an unusually large number of highly fragmented genes, many encoding outer membrane proteins, which may have been destroyed in order to bypass deleterious responses from the feline host immune system. In addition, the few Sheeba-specific genes that were found include a cluster of genes encoding sialylation of the bacterial cell surface carbohydrates, which were imported by horizontal genetic exchange and might also help to evade host immune defenses. These results provide a genomic basis for elucidating molecular events that allow bacteria to adapt to novel animal hosts.

Animals↗
PubMed2003

Colonic spirochetosis of colony-raised rhesus macaques associated with Brachyspira and Helicobacter.

Colonic spirochetosis is an inflammatory bowel disease that affects a broad range of hosts, including human and non-human primates. The disease in humans and non-human primates is characterized by intimate attachment of the anaerobic spirochetes Brachyspira aalborgi and B. pilosicoli, and some unclassified flagellated microbes along the apical membrane of colonic enterocytes. Although the presence of spiral-shaped bacteria with single polar flagella and blunted ends in colonic spirochetosis is well established, the identities of many of these organisms is still unknown. Recently, Helicobacter species with a morphology similar to the flagellated bacteria present in colonic spirochetosis have been cultured from intestinal specimens obtained from rhesus macaques, some with idiopathic colitis. The purpose of the present study was to determine whether or not the flagellated bacteria seen in the colons of rhesus macaques with colonic spirochetosis are Helicobacter. The presence of flagellated bacteria alone (n=2) or together with spirochetes (n=1) in formalin-fixed and paraffin-embedded colons of three rhesus macaques with the naturally occurring disease was demonstrated by immunohistochemical staining and ultrastructural examination. Total DNA extracted from affected and control intestinal specimens was amplified by polymerase chain reaction (PCR) using Helicobacter 16S rRNA gene-specific primers. Comparative nucleotide sequence analysis of PCR products cloned from positive reactions indicated that two distinct Helicobacter genomospecies were present either alone or in combination with Brachyspira in the colons of rhesus macaques with microscopic lesions indicative of colonic spirochetosis.

Journal Article↗
PubMed1991

Revision of Campylobacter, Helicobacter, and Wolinella taxonomy: emendation of generic descriptions and proposal of Arcobacter gen. nov.

Hybridization experiments were carried out between DNAs from more than 70 strains of Campylobacter spp. and related taxa and either 3H-labeled 23S rRNAs from reference strains belonging to Campylobacter fetus, Campylobacter concisus, Campylobacter sputorum, Campylobacter coli, and Campylobacter nitrofigilis, an unnamed Campylobacter sp. strain, and a Wolinella succinogenes strain or 3H- or 14C-labeled 23S rRNAs from 13 gram-negative reference strains. An immunotyping analysis of 130 antigens versus 34 antisera of campylobacters and related taxa was also performed. We found that all of the named campylobacters and related taxa belong to the same phylogenetic group, which we name rRNA superfamily VI and which is far removed from the gram-negative bacteria allocated to the five rRNA superfamilies sensu De Ley. There is a high degree of heterogeneity within this rRNA superfamily. Organisms belonging to rRNA superfamily VI should be reclassified in several genera. We propose that the emended genus Campylobacter should be limited to Campylobacter fetus, Campylobacter hyointestinalis, Campylobacter concisus, Campylobacter mucosalis, Campylobacter sputorum, Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and "Campylobacter upsaliensis." Wolinella curva and Wolinella recta are transferred to the genus Campylobacter as Campylobacter curvus comb. nov. and Campylobacter rectus comb. nov., respectively. Bacteroides gracilis and Bacteroides ureolyticus are generically misnamed and are closely related to the genus Campylobacter. Campylobacter nitrofigilis, Campylobacter cryaerophila, and an unnamed Campylobacter sp. strain constitute a new genus, for which the name Arcobacter is proposed; this genus contains two species, Arcobacter nitrofigilis comb. nov. (type species) and Arcobacter cryaerophilus comb. nov. Wolinella succinogenes so far is the only species of the genus Wolinella. The genus Helicobacter is also emended; Campylobacter cinaedi and Campylobacter fennelliae are included in this genus as Helicobacter cinaedi comb. nov. and Helicobacter fennelliae comb. nov., respectively. The genus "Flexispira," with "Flexispira rappini" as the only species, is closely related to the genus Helicobacter. The free-living, sulfur-reducing campylobacters do not belong to any of these genera; they probably constitute a distinct genus within rRNA superfamily VI.

Bacterial Typing Techniques↗
PubMed2002

Detection of Helicobacter pylori using nested polymerase chain reaction and rapid urease test in gastric biopsy samples.

BACKGROUND/AIMS: The purpose of this study was to compare nested polymerase chain reaction and rapid urease test findings in the diagnosis of Helicobacter pylori infection. METHODS: Two gastric biopsy specimens were obtained from each of 64 patients and polymerase chain reaction and rapid urease test were performed. DNA extraction was followed by amplification with two primer pairs from the urease A gene of Helicobacter pylori genome. RESULTS: Fourty two patients (65.6%) had a positive rapid urease test result while 22 (34.4%) had a negative result for Helicobacter pylori. Sixty of 64 patients (93.8 %) had a positive result with the nested polymerase chain reaction method. Four patients with negative nested polymerase chain reaction results also had negative rapid urease test results. All of the eighteen patients with rapid urease test-negative results were positive with nested polymerase chain reaction. The number of nested polymerase chain reaction-positive patients (93.8%) was significantly higher than rapid urease test-positive (65.6%) and first round polymerase chain reaction-positive (53.1%) patients (P<0.001). CONCLUSIONS: Our results indicate that the nested polymerase chain reaction is more specific and sensitive than the rapid urease test for detecting Helicobacter pylori in gastric biopsy samples.

Journal Article↗