Binding of the Helicobacter pylori vacuolating cytotoxin to target cells

The vacuolating cytotoxin of Helicobacter pylori, VacA, enters the cytoplasm of target cells and causes vacuolar degeneration by interfering with late stages of endocytosis. By using indirect immunofluorescence and flow cytometry, we have demonstrated that VacA binds to specific high-affinity cell surface receptors and that this interaction is necessary for cell intoxication.     

From bench to bedside and back--report on the European Helicobacter pylori Study Group Xth International Workshop on Gastroduodenal Pathology and Helicobacter pylori

The Xth International Workshop on Gastroduodenal Pathology and Helicobacter pylori was held in Lisbon, Portugal, from September 12 to 14, 1997. State-of-the-art reviews and research findings were presented to over 2000 participants. This review focuses on important new developments and serves as a rapid communication of clinically relevant material.     

Prospects for the development of a vaccine against Helicobacter pylori

Over 50% of the world population is chronically infected by the gastric pathogen, Helicobacter pylori, which is responsible for most peptic ulcer disease and is closely associated with adenocarcinoma of the stomach. Current therapies for peptic ulcer disease include antibiotic eradication of H. pylori infection. While effective, the high cost, difficulty of patient compliance with the treatment regimens, and risks of selection for resistant strains make these therapies impractical on a large scale. Studies of the pathogenesis of H. pylori have led to the identification of bacterial antigens as candidates for inclusion in novel vaccines against this disease. Both prophylactic and therapeutic vaccination have been demonstrated in animal models of Helicobacter infection. Preclinical evaluations of several antigens are at present under way and trials of vaccination in humans are planned.     

Guidelines for the treatment of Helicobacter pylori in the pediatric population

Several factors including long-term eradication of the organism, cost, compliance, and adverse event profile should be considered for treating H. pylori infection in pediatric patients. Triple therapy with bismuth, tetracycline, and metronidazole is considered the gold standard for adult patients; however, tetracyclines are not recommended in children younger than 8 years due to the potential for tooth discoloration and alterations in bone growth. Dual and shorter duration of therapy should be evaluated in children with H. pylori. The new dual therapy omeprazole/clarithromycin regimens approved by the Food and Drug Administration for adults may be considered as an alternative for children when concerns include the use of salicylates or allergy to beta-lactams. Although the dosage of omeprazole in pediatric patients has not been established (no pediatric formulation exists), clarithromycin is available for use in pediatric patients. However, these drugs cannot be recommended for children with H. pylori until additional studies in this population are available. Based on the available data, aminopenicillin/bismuth or aminopenicillin/tinidazole combinations appear to be effective in eradicating H. pylori in children. Amoxicillin 50 mg/kg/d plus bismuth subsalicylate (< 10 y, 262 mg; > 10 y, 525 mg qid) or bismuth subcitrate (< 12 y, 120 mg; > 12 y, 240 mg bid) can be used for 6 weeks. The bismuth dosages represented above were those used in various studies. It should be realized, however, that a definitive dosage of bismuth subsalicylate for children in the treatment of H. pylori has not been established. The adult dosage of bismuth subsalicylate for the eradication of H. pylori is the same as that used for prophylaxis in diarrhea (525 mg qid). When dosage of this agent is unknown (particularly for the treatment of very young children), the use of established dosages for prophylaxis in diarrhea may be considered for treating H. pylori. Additionally, bismuth subsalicylate should be used with caution in children with suspected viral infections (i.e., to prevent Reye's syndrome) or those receiving concurrent therapy with interacting drugs. If available, tinidazole 20 mg/kg/d can be used with amoxicillin 50 mg/kg/d for 6 weeks to treat children infected with H. pylori.     

Touch cytology. A reliable and cost-effective method for diagnosis of Helicobacter pylori infection

A variety of reliable methods are available for detecting Helicobacter pylori (Hp) during upper gastrointestinal endoscopy. We evaluated the clinical utility and cost-effectiveness of rapid urease test (RUT), touch cytology (TC), and histology (H). Two hundred thirty-eight consecutive patients (178 without previous medical treatment and 60 formerly treated with anti-Hp therapy) were tested for Hp infection by RUT, TC, and H (H&E stain). The infection status for each patient was established by a concordance of two test results. The time to carry out the three tests and their cost were also calculated. Sensitivity of TC (100%) was significantly higher than that of RUT (86.8%; P < 0.001), but not than that of H (94.9%). RUT was significantly more specific than H (100% vs 95.6%; P < 0.05), but not than TC (96.4%). Hp infection was more frequent in the patients with chronic active gastritis than in those with chronic nonactive gastritis (P < 0.001). No Hp infection was detected in absence of chronic antral inflammation. RUT resulted the cheapest method and H the most expensive; TC is faster and cheaper than H. When additional information about the severity of mucosal damage or the presence of cell atypias is not necessary, histologic examination can be omitted, and a cost-effective strategy for assessing Hp status might consist in taking two antral biopsies, the former for performing RUT and the latter for preparing a slide by TC, which should be stained and examined only when the RUT result is negative.     

Helicobacter pylori colonization of Barrett's esophagus and its progression to cancer

Helicobacter pylori (HP) plays a crucial role in gastric carcinogenesis. Few studies have looked at the relationship between HP and Barrett's esophagus/cancer. To further investigate this, a study comparing the prevalence of HP and increasing grades of dysplasia was undertaken. Biopsies from 19 malignant and 94 benign cases of Barrett's esophagus were analysed histologically for the presence of HP. 34% of non-dysplastic Barrett's epithelium was colonized with HP compared with only 17% of dysplastic/malignant cases (P = 0.04). No relationship was found between HP status and: (i) length of Barrett's esophagus; (ii) the presence of ulcers or strictures; and (iii) previous anti-reflux surgery. HP colonization of Barrett's esophagus is not uncommon. We found that HP has a negative correlation with increasing dysplasia which is analogous to gastric carcinogenesis. This finding should be investigated in prospective studies to elucidate its role in Barrett's adenocarcinoma.     

Parietal cells in the duodenal bulb and their relation to Helicobacter pylori infection

AIM: To investigate the prevalence, and relation to Helicobacter pylori, of parietal cells in the duodenal bulb using a monoclonal antibody directed against H+,K(+)-ATPase (HK12.18). METHODS: Twenty six patients with duodenal ulcer disease and 16 healthy controls were studied. H pylori status was determined by gastric histology and culture and by the 13C-urea breath test. Four biopsy specimens were taken from the duodenal bulb and stained with HK12.18. The presence/absence and number of parietal cells in the duodenal bulb were assessed blindly by a histopathologist. RESULTS: The overall prevalence of parietal cells in the duodenal bulb was 31% (13/42) and was similar in patients with duodenal ulcer and in controls, and in H pylori positive and negative subjects. The median (range) number of parietal cells in the duodenal bulb was 7.5 (4-20) parietal cells/subject, and was similar in all four groups. CONCLUSIONS: The prevalence of parietal cells in the duodenal bulb (31%) is notably higher than previously reported in endoscopic studies, and is in keeping with reports from studies on necropsy/operative specimens. There was no difference in the prevalence or number of parietal cells in the duodenal bulb between patients with duodenal ulcer and controls, regardless of H pylori status. These findings suggest that parietal cells in the duodenal bulb do not contribute to the pathogenesis of duodenal ulcer.     

Antral gastritis in chronic alcoholism. Role of cirrhosis and Helicobacter pylori

OBJECTIVES: Antral gastritis is frequent in alcoholics. The role of H. pylori in the pathogenesis of gastritis in these patients is not well known. The aim of our study was to study the role of H. pylori and cirrhosis in the pathogenesis of antral gastritis in alcoholic patients. METHODS: Seventy-nine patients were included in the study. All underwent upper gastrointestinal tract endoscopy with antral biopsies, independently of the presence of abdominal pain, and had serological examination for H. pylori antibodies. RESULTS: Cirrhosis and gastritis were present in 50 and 40 patients respectively, H. pylori serological assay and histological identification of the bacterium were positive in 35 (44%) and 19 (24%) patients respectively. Discrepancy between the 2 tests were observed more frequently in cirrhotic patients. A positive serology with a negative histologic examination for H. pylori was present for 18 cirrhotic and 4 noncirrhotic patients (p < 0.05). A gastritis without evidence of H. pylori was more frequent in cirrhotic than in noncirrhotic patients. H. pylori was histologically present in 11 of 29 cirrhotic patients and in 8 of the 11 noncirrhotic patients with a gastritis (p < 0.05). CONCLUSIONS: Discrepancies between histological examination and H. pylori serology in patients with cirrhosis might be due to the inhospitable environment for H. pylori in case of portal hypertension; the positive serology could be in relation with a past infection.     

Helicobacter pylori infections in children in the tropical zone. Endoscopic and histological aspects

AIMS: To assess the endoscopic and histological aspects of Helicobacter pylori (H. pylori) infection in children in a prospective study. PATIENTS AND METHODS: One hundred and four children (6 months-15 years old), with digestive symptoms admitted to the Pediatric Department of the National Hospital of Ouagadougou between February Ist and October 31 1996, underwent upper digestive endoscopy with fundic and antral biopsies for histological and bacteriological analysis. RESULTS: Endoscopy was normal in 80 cases (77%). No lesion was specific of H. pylori infection. Nodular gastritis was observed in 3% of the cases only. Duodenal ulcers were seen in 3 children (3%). 83% of the children had chronic antral gastritis, associates with H. pylori in 95% of the cases. The lesions were follicular gastritis (45%), mild atrophic gastritis (38.5%) and lymphocytic gastritis (1%). Follicular gastritis was more pronounced in the antrum than in the fundus. CONCLUSION: The high prevalence of early H. pylori infection and chronic gastritis in children contrasts with the rarity of gastric cancer in black Africa. Protective factors or peculiar strains should be searched for.     

Helicobacter pylori infection, gastritis, and the temperature of choice for hot drinks

A 44-year-old male presented with a solitary cerebellopontine angle (CPA) metastasis from lung cancer. His initial symptoms were vertigo and hearing loss beginning 5 months after the diagnosis of the primary cancer. Two months later, right facial paresis developed. His neurological deterioration was rapid. Magnetic resonance (MR) imaging with enhancement disclosed the CPA tumor. The tumor was partially removed through the retroauricular retromastoid approach. Histological examination of the specimen revealed adenocarcinoma. The characteristic rapidly progressive symptoms and MR imaging with enhancement are the most sensitive and essential examinations for this lesion.     

Prevalence of primary Helicobacter pylori resistance to metronidazole and clarithromycin in The Netherlands

The minimum inhibitory concentrations of metronidazole and clarithromycin were determined for 780 Helicobacter pylori strains collected in 1994 and 1995 from three different regions in The Netherlands. The overall prevalence of primary metronidazole resistance was 17%, with resistance found more frequently in women (24%) than in men (13%). There was no significant difference between the levels of resistance in the three regions. Primary clarithromycin resistance was rare (1%) and relatively infrequent as compared to that found in other countries. Four of the six strains resistant to clarithromycin were also resistant to metronidazole.     

Marshall McLuhan and the psychology of television.

Describes the origins and development of M. McLuhan's (e.g., 1964, 1973) central ideas about TV's effects on the human mind and clarifies how he reached theoretical positions that were often diametrically opposed to psychological views of TV. Psychological influences on McLuhan's work and reasons why McLuhan was not well understood by psychologists are explored. Social-psychological and learning theory-based studies of TV effects had little impact on McLuhan's thinking; rather he was heavily influenced by earlier concepts from the fields of sensation and perception. McLuhan combined these concepts with his views on the nature of art, which were influenced by the Symbolists and the "new criticism" movement within English literature, and with the historical insights of H. Innis (1950) to elaborate his unique views of the effects of media. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)