Helicobacter pylori infection: independent risk indicator of gastric adenocarcinoma

Helicobacter pylori infection and gastric juice vitamin C levels. Impact of eradication

H. pylori has recently been recognized as a novel risk factor of gastric cancer, but its precise role in gastric carcinogenesis is as yet unknown. The aim of the present study was to assess the relationship between H. pylori infection and vitamin C levels in gastric juice and also to examine whether eradication of H. pylori could have any impact on these levels. Gastric juice and plasma vitamin C levels were measured in 88 dyspeptic patients who had an upper gastrointestinal endoscopy. In the subgroup of H. pylori-positive patients, eradication was attempted with triple therapy. This subgroup was studied on two occasions, ie, before and after treatment. There were 58 H. pylori-positive and 30 -negative patients. Gastric juice vitamin C levels in H. pylori-positive patients were statistically lower (P < 0.001) than the levels in the H. pylori-negative patients. Triple therapy achieved eradication in 45 patients (77.6%) of the 58 H. pylori-positive patients. Before H. pylori was eradicated in these 45 patients gastric juice vitamin C levels were significantly (P < 0.001) lower than those after eradication, the latter being no different than the group of 30 H. pylori-negative patients. There was a significant (P < 0.001) improvement of gastritis after eradication, which paralleled the elevation of gastric juice vitamin C levels. No difference was noted in plasma vitamin C levels between H. pylori-negative and -positive patients or in the latter before and after H. pylori treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of four new prokaryotic bacterioferritins, from Helicobacter pylori, Anabaena variabilis, Bacillus subtilis and Treponema pallidum, by analysis of gene sequences

The nucleotide (nt) sequence of the Helicobacter pylori (Hp) napA gene, encoding neutrophil-activating protein A (HPNAP) was determined. Alignment of this sequence with those of known bacterioferritins (Bfr) revealed sequence homology and conservation of a 7-amino-acid (aa) motif constituting the ferroxidase (Frx) center of Bfr in the HPNAP. The N-terminal aa sequence deduced from the iron-regulated mrgC gene of Bacillus subtilis [Chen et al., J. Bacteriol. 175 (1993) 5428-5437] is highly similar to that of HPNAP and contains five Frx center aa residues. The deduced aa sequences for proteins of unknown function in Treponema pallidum [Walfield et al., Infect. Immun. 57 (1989) 633-635] and in the cyanobacterium Anabaena variabilis [Sato, GenBank accession No. JU0384 (1991)] identify these two proteins as Bfr. Although the DNA-binding protein from starved cells of Escherichia coli [Almiron et al., Genes Dev. 6 (1992) 2646-2654] is clearly a HPNAP/Bfr homologue, a significant part of its Frx center is missing. It is unlikely that the intracellular function of HPNAP is related to its ability to activate neutrophils.

Triple therapy with ranitidine, clarithromycin, and metronidazole in the treatment of Helicobacter pylori

BACKGROUND

To determine whether a triple therapy regimen for the treatment of Helicobacter pylori infection, consisting of ranitidine 300 mg q.i.d., clarithromycin 500 mg t.i.d., and metronidazole 500 mg t.i.d. would provide a safe and effective treatment regimen, we performed an open prospective study in 20 consecutive patients with proven H. pylori-associated non-ulcer dyspepsia or peptic ulcer disease.

METHODS

The percentage of patients in whom eradication of H. pylori succeeded was determined. A semiquantitative assessment of histology was performed, and the results were analysed using Wilcoxon's matched-pairs ranks tests; side effects were noted and graded.

RESULTS

Eradication was achieved in 19 of 20 patients, i.e. in 95% (confidence interval 85-100%). Eradication of the bacterium led to a significant improvement in semiquantitative histology scores; active antral inflammation decreased from (mean +/- SEM) 1.84 +/- 0.19 to 0.21 +/- 0.16 (p = 0.0004) and chronic antral inflammation from 2.47 +/- 0.14 to 1.16 +/- 0.14 (p = 0.0002); active gastric body inflammation decreased from 0.95 +/- 0.19 to 0.00 +/- 0.00 (p = 0.0015) and chronic inflammation from 1.68 +/- 0.17 to 0.32 +/- 0.11 (p = 0.0007). Side effects occurred in 45% of patients, but in over half of these patients only mild side effects occurred. Severe side effects did not occur, none of the patients discontinued the triple therapy.

CONCLUSIONS

Triple therapy with ranitidine, clarithromycin, and metronidazole provides a safe and effective treatment of H. pylori infection, resulting in a high eradication rate, and in significant decrease in semiquantitative histology scores. Further prospective studies are warranted.

Helicobacter pylori: the new bug on the (paraffin) block

A nameless spirillar organism in search of a disease only a few years ago, Helicobacter pylori has seen its fortunes suddenly reversed. After a rapid succession of name changes and some acrimonious disputes across continents, in less than a decade H. pylori has been catapulted to the centre stage of gastroenterological and microbiological research and has topped the most-wanted list of the pharmaceutical industry. The discovery of H. pylori has provided the momentum for the formation of the group that eventually created the Sydney System. Today, H. pylori is increasingly recognized as one of the most prevalent human pathogens worldwide. Its causal association with chronic active gastritis is undisputed and its role in the pathogenesis of peptide ulcer disease, although still poorly understood, is universally accepted. Furthermore, possible connections between chronic H. pylori infection and gastric carcinoma and primary gastric lymphoma are now being explored with increasing alacrity. With a few notable exceptions, pathologists have remained passive spectators of these exciting discoveries and have allowed gastroenterologists and microbiologists to set the pace in the quest for the determinants of gastritis, peptic ulcer and gastric cancer. This article is intended to outline some of the accepted facts on the development, progression, and pathology of H. pylori gastritis and to pose questions about this elusive infection. The authors hope that it might also contribute to stimulate further research, particularly on those aspects that are eminently suited to be addressed by pathologists.

Adenocarcinoma of the esophagus and esophagogastric junction in white men in the United States: alcohol, tobacco, and socioeconomic factors

In the United States, the incidence of adenocarcinoma of the esophagus, including the esophagogastric (EG) junction, has been increasing rapidly over the past two decades. Except for an association with Barrett's esophagus, little is known about the etiology of these cancers. A population-based case-control interview study of 174 White men with adenocarcinoma of the esophagus and 750 controls living in three areas of the United States offered the opportunity to investigate the relationship of these cancers with smoking, alcohol drinking, socioeconomic factors, and history of ulcer. There were significantly elevated risks for men who smoked cigarettes (odds ratio [OR] = 2.1) or drank liquor (OR = 1.6). For both cigarette smoking and liquor drinking, there were significant dose gradients with amount consumed. No reduction in risk was observed following smoking cessation. Subjects who switched from nonfilter to filter cigarettes experienced half the risk of those who only smoked nonfilter cigarettes. Inverse risk gradients were seen with increasing recent annual income, with the highest risk (OR = 3.4) for the lowest category. The risk for a history of ulcer (OR = 1.7), especially of the duodenum (OR = 2.2), was also significantly elevated. These data suggest that tobacco and alcohol may be etiologic factors for adenocarcinoma of the esophagus and EG junction, but these factors do not appear to explain the rapid rise in incidence of these tumors. The associations with low social class and history of ulcer need to be explored in greater detail along with other factors that may account for the temporal trends in esophageal adenocarcinomas.

Diet, Helicobacter pylori infection, food preservation and gastric cancer risk: are there new roles for preventative factors?

Risks for gastric cancer in relation to diet and other environmental factors are receiving renewed attention. New developments include the emerging relationship between Helicobacter pylori infection and an increased risk for gastric cancer, and positive results of chemoprevention trials in decreasing gastric cancer risk with the use of beta-carotene and vitamin E supplements. Factors that may enhance risk include consumption of nitrites, nitrates, alcohol, and highly salted, pickled, fermented, or smoked foods. Other environmental factors which may promote cancer are H. pylori infection, inappropriate food storage, metal and cement dust exposure, and cigarette smoking. High intakes of fruits and vegetables or of antioxidants, such as beta-carotene, vitamin E, and vitamin C may decrease risk.

Helicobacter pylori epidemiology in relation to peptic ulcer and gastric cancer in south and north China

Peptic ulcer disease is twice as common in people living in South China when compared with those in North China. However, the gastric cancer rate in North China is three times that of South China. The overall Helicobacter pylori prevalence rate is similar in North and South China populations and it is higher than Caucasians living in Western societies. However, there is a significantly higher prevalence of H. pylori seropositivity among those who live in the high gastric cancer areas of China. On the other hand, there is no significant difference in the H. pylori positive rate in the peptic ulcer disease patients between the two regions of China. Other permissive/associated co-factors in the development of peptic ulcer disease or gastric cancer remain unknown at this stage.