A prospective study of atrophic gastritis and stomach cancer risk

Inhibitory actions of luteolin on the growth and arylamine N-acetyltransferase activity in strains of Helicobacter pylori from ulcer patients

Helicobacter pylori is now recognized as an important cause of type B gastritis, which is strongly associated with gastric and duodenal ulcer disease. H. pylori may be a causative factor in patients with gastric cancer. The growth inhibition and N-acetylation of 2-Aminofluorene (AF) or P-aminobenzoic acid (PABA) by arylamine N-acetyltransferase (NAT) in H. pylori were inhibited by luteolin, a component in herbal medicine. The growth inhibition was based on the changes of optical density (OD) by using a spectrophotometer. The N-acetylation of AF or PABA by NAT from H. pylori were assayed by the amounts of acetylated and non-acetylated AF or PABA in cytosols and intact bacteria of H. pylori by using HPLC. An inhibition of growth on H. pylori demonstrated that luteolin elicited a dose-dependent growth inhibition in the H. pylori cultures. Cytosols and suspensions of H. pylori with or without specific concentrations of luteolin co-treatment showed different percentages of AF or PABA acetylation. The data indicated that there was decreased NAT activity associated with increased levels of luteolin in H. pylori cytosols and suspensions. Using standard steady-state kinetic analysis, it was demonstrated that luteolin was a possible uncompetitive inhibitor to NAT enzyme in H. pylori. This report is the first demonstration to show that luteolin can inhibit H. pylori growth and NAT activity.

Effects of polyunsaturated fatty acids on atrophic gastritis in a Japanese population

In the present study, 92 people were found to have atrophic gastritis (AG) according to depressed serum levels of pepsinogen I and pepsinogen II in a screening involving 208 Japanese people, participating in a group health check. Serum levels of n-3 polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), were higher in AG than in non-AG individuals, while those of gamma-linolenic acid (GLA) were significantly lower in AG individuals. The odds ratios for high serum DHA and GLA levels in AG subjects were 2.20 (95% C.I.: 1.10-4.39) and 0.34 (95% C.I.: 0.17-0.68), respectively. The above results suggested that GLA plays a role in reducing the incidence of AG, whereas DHA may increase a risk of AG.

Synergistic interaction between Helicobacter pylori gastritis and diet in gastric cancer

Infection with Helicobacter pylori increases the risk of gastric cancer. One possible mechanism is the higher likelihood of malignant transformation due to inflammatory responses in the epithelium. An alternative explanation is that these inflammatory responses induce chronic gastritis associated with decreased acidity in the stomach, which in turn increases the endogenous formation of carcinogenic N-nitroso compounds. Inflammatory responses seem to trigger two different causal pathways: one for the diffuse type of gastric cancer and the other for the intestinal type. The striking geographic variability in intestinal gastric cancer can be explained by the synergistic interaction between H. pylori infection and dietary factors, such as intake of salt and ascorbic acid. Screening and eradication of this organism, together with appropriate dietary modifications, offer promise in countries with a high prevalence of H. pylori infection and high risk of gastric cancer, but the safety of such interventions needs to be ensured.

Severity of chronic atrophic gastritis and subsequent gastric cancer occurrence: a 10-year prospective cohort study in Japan

Chronic atrophic gastritis is regarded as a predisposing factor for gastric cancer associated with Helicobacter pylori infection, and its severity is suggested to be a key influence on gastric cancer risk. Our purpose was to elucidate chronological change in cumulative risk of gastric cancer occurrence with various degrees of chronic atrophic gastritis by long-term follow-up. A total of 5373 subjects without cancer or resected stomachs who underwent gastroscopic examination and completed a life-style questionnaire between 1985-1989 were prospectively followed until December 1999. Relative risks of gastric cancer associated with baseline endoscopic findings were estimated using hazard ratios and their 95% confidence intervals with the Cox proportional hazard model, adjusting for gender, age and gastric cancer family history. After an average of 10 years of follow-up, 117 gastric cancer cases were identified. The risk was greatest among the subjects with moderate atrophy at baseline (hazard ratio: 2.22) and 4-6 years of follow-up (hazard ratio: 4.6-5.0). After this time point, risk attenuation with the length of follow-up period was observed. Our study gives the supportive evidence to the hypothesis that incomplete chronic atrophic gastritis and the processes occurring in atrophy are associated with development of gastric cancer.

Trend toward a reduced prevalence of Helicobacter pylori infection, chronic gastritis, and gastric cancer in Japan

It is speculated that declines in H. pylori infection and gastritis over the past few decades may lead to a decline in gastric cancer in Japan, supplemented by excellent procedures for the early detection of gastric cancer. Because H. pylori infection rarely is acquired in adult life, once it is eradicated, reinfection would not be expected in adult patients. It seems likely that adequate treatment of H. pylori infection would provide long-term protection against gastric cancer.

Gastric mucosal inflammation and epithelial cell turnover are associated with gastric cancer in patients with Helicobacter pylori infection

BACKGROUND

Infection with a virulent Helicobacter pylori strain is associated with gastric mucosal damage and the increased risk of gastric cancer.

AIMS

To examine the characteristics of host gastric mucosal responses in patients with gastric cancer, histological grade of gastritis, gastric epithelial apoptosis, and proliferation were studied.

METHODS

Thirty two patients with early gastric cancer and 32 sex and age matched controls were studied. All subjects were infected with a virulent H pylori strain (vacA s1/m1, cagA positive genotype). Biopsy specimens were taken from the antrum and the corpus of the stomach. The grade of gastritis was assessed according to the updated Sydney system. Apoptotic cells were detected using terminal uridine deoxynucleotidyl nick end labelling, and epithelial cell proliferation was determined by means of the Ki-67 labelling index.

RESULTS

In patients with gastric cancer, significantly higher grades were observed when glandular atrophy (p < 0.05) and intestinal metaplasia (p < 0.01) were present in the antrum, and when mononuclear cell infiltration was present in the corpus (p < 0.05). The numbers of apoptotic cells were increased in patients with cancer (p < 0.05) and the apoptotic index correlated significantly with the grade of glandular atrophy. Epithelial cell proliferation was more likely to be increased in mucosa where intestinal metaplasia was present.

CONCLUSIONS

Infection with H pylori causes increased gastric epithelial apoptosis, resulting in more severe glandular atrophy in patients with gastric cancer. Increased damage of gastric epithelial DNA and the presence of more severe atrophic gastritis might contribute to the development of gastric cancer.

Relationship between serologically diagnosed chronic atrophic gastritis, Helicobacter pylori, and environmental factors in Japanese men

BACKGROUND

Whereas chronic atrophic gastritis is known to be an intermediate stage in gastric carcinogenesis, information is sparse about factors associated with this precancerous lesion except for Helicobacter pylori.

METHODS

In a cross-sectional study of 566 men aged 50-55 years in the Japan Self-Defense Forces, we examined the relation of H. pylori infection, smoking, alcohol use, and dietary factors to the prevalence of chronic atrophic gastritis as determined by serum pepsinogen I and pepsinogen II (I/II ratio < 3.0. and pepsinogen I < 70 ng/ml). Chronic atrophic gastritis was classified as severe when the pepsinogen I/II ratio was < 2.0, and as moderate otherwise.

RESULTS

The overall prevalence of chronic atrophic gastritis was 35.7% (202 of 566). The seropositivity of H. pylori was associated with a 10-fold increase in the risk of chronic atrophic gastritis, and the association was much stronger for moderate atrophic gastritis. Neither cigarette smoking nor alcohol consumption was related to the overall risk of chronic atrophic gastritis. Consumption of vegetables and fruits was each unrelated to chronic atrophic gastritis whether examined as a whole or separately for moderate and severe atrophic gastritis. Green tea was related to decreased risk of severe atrophic gastritis, although not statistically significant, whereas garlic consumption showed no protective association.

CONCLUSIONS

The findings corroborate that H. pylori infection has an important role in the development of chronic atrophic gastritis in middle-aged Japanese men. Green tea consumption may be protective against the advance of atrophic gastritis. Vegetables, fruits, or garlic had no protective effect against the development of atrophic gastritis in the study.

Effects of three-month oral supplementation of beta-carotene and vitamin C on serum concentrations of carotenoids and vitamins in middle-aged subjects: a pilot study for a randomized controlled trial to prevent gastric cancer in high-risk Japanese population

Prior to a randomized controlled trial to prevent gastric cancer by oral supplementation of beta-carotene and vitamin C in a high-risk Japanese population, we examined the serum response to three-month oral supplementation of beta-carotene (0, 3, 30 mg / day) and vitamin C (0, 50, 1000 mg / day) by a three-by-three factorial design using 54 subjects (age range = 40 - 69 years). Serum concentrations of carotenoids, alpha-tocopherol, and ascorbic acid were examined at baseline, and one, two, and three-month points. Both serum beta-carotene and ascorbic acid were significantly higher in high-dose groups than in each placebo group during the supplementation. The serum beta-carotene increased gradually (597 - 830% increase) during the study, whereas the serum ascorbic acid reached nearly a steady-state at the one-month point and remained stable thereafter (88 - 95% increase). No statistically significant interaction between beta-carotene and vitamin C supplementations was observed either for serum beta-carotene or for serum ascorbic acid. Among carotenoids and alpha-tocopherol examined, serum lycopene in the high-dose beta-carotene group was significantly higher than in the placebo group at all points. No unfavorable change in carotenoids and alpha-tocopherol was observed in any group.

Garlic and onions: their effect on eicosanoid metabolism and its clinical relevance

Garlic (Allium sativum) and onion (Allium cepa) are among the oldest of all cultivated plants. Additionally, both plants have been used as medicinal agents for thousands of years. Both garlic and onion have been shown to have applications as antimicrobial, antithrombotic, antitumor, hypolipidaemic, antiarthritic and hypoglycemic agents. In recent years, extensive research has focussed on the beneficial and medicinal properties of garlic and onions. In particular, the use of these agents in the treatment and prevention of cardiovascular disease and cancer is an area of considerable investigation and interest.

Evolution of precancerous lesions in a rural Chinese population at high risk of gastric cancer

The pathogenesis of gastric cancer (GC), particularly of the intestinal type, is thought to involve a multistep and multifactorial process. Our objective was to determine the rates of transition from early to advanced gastric lesions in a population in Linqu County, China, where the GC rates are among the highest in the world. An endoscopic screening survey was launched in 1989-1990 among 3,399 residents aged 34-64 years with precancerous lesions diagnosed from biopsies taken from 7 standard locations in the stomach and from any suspicious sites. The cohort was subsequently followed, with endoscopic and histopathologic examinations conducted in 1994. Logistic regression analysis was used to estimate odds ratios (ORs) of progression to advanced lesions of various levels of severity as a function of age, sex and baseline pathology. The rates of progression were higher among older subjects, among men and among subjects with more extensive gastric lesions. 34 incident GCs were identified during the follow-up period. The ORs of GC, adjusted for age and sex, varied from 17.1, for those with baseline diagnoses of superficial intestinal metaplasia (IM), to 29.3, for those with deep IM or mild dysplasia (DYS) or IM with glandular atrophy and neck hyperplasia, to 104.2, for those with moderate or severe DYS, as compared with subjects with superficial gastritis (SG) or chronic atrophic gastritis (CAG) at baseline. Our prospective study of a high-risk population revealed sharp increases in the risk of GC and advanced precursor lesions according to the severity of lesions diagnosed at the start of follow-up. Int. J. Cancer, 83:615-619, 1999. Published 1999 Wiley-Liss, Inc.

Most gastric cancer occurs on the distal side of the endoscopic atrophic border

BACKGROUND

The endoscopic atrophic border indicates the extent of atrophic gastritis. The aims of this study were to examine the relation of intestinal and diffuse types of gastric cancer to the atrophic border and to study the pathologic condition of the atrophic border.

METHODS

In 83 patients with gastric cancer the extent of atrophic gastritis was assessed macroscopically. In 46 patients gastric biopsy specimens were also taken, to compare the histologic features of gastritis proximal and distal to the atrophic border.

RESULTS

Eighty-five per cent of gastric cancers (including 93% of intestinal type) occurred on the distal side of the atrophic border. Early diffuse gastric cancer arose closer to the atrophic border than intestinal-type cancer and was more likely to be sited proximal to it. Histologically, the grade of polymorphonuclear cell infiltration (inflammatory activity) and Helicobacter pylori density were significantly greater on the proximal side (P < 0.05), whereas the grades of glandular atrophy and intestinal metaplasia were significantly greater distally (P < 0.001).

CONCLUSIONS

The atrophic border delineates the area of atrophic gastritis and intestinal metaplasia, and it is within the distal part of the stomach that gastric cancer occurs most frequently. Endoscopists should observe the distal side particularly carefully to identify early gastric cancer. The relationship of the two histologic types of cancer to areas of intestinal metaplasia and 'active' inflammation may have implications for the pathogenesis of cancer and, if so, for the potential protective effect of H. pylori eradication.

Helicobacter pylori infection on the risk of stomach cancer and chronic atrophic gastritis

Helicobacter pylori infection is associated with gastric adenocarcinoma. However, the mechanisms of this interaction are still unclear. This study was conducted to explore the effects of H. pylori infection on early and late stage gastric carcinogenesis. This study included 134 patients with adenocarcinoma of the stomach (ACS), 67 patients with chronic atrophic gastritis (CAG), and 65 normal controls recruited at Memorial Sloan-Kettering Cancer Center (MSKCC) from November 1, 1992 to November 1, 1994. Epidemiologic data were collected by a modified National Cancer Institute Health Habits History Questionnaire. H. pylori infection was diagnosed by pathological evaluation. Risk factors were analyzed using logistic regression. The odds ratio (OR) associated with H. pylori infection was 10.4 [95% confidence interval (CI): 2.6-41.6] for CAG and 11.2 (95% CI: 2.5-50.3) for gastric cancer in comparison with normal controls, with adjustment for pack-years of smoking, alcohol drinking, body mass index, total caloric intake, dietary fat and fiber intake, and Barrett's esophagus. But H. pylori infection was not associated with risk of stomach cancer when patients with stomach cancer were compared with patients with CAG (OR = 0.6, 95% CI: 0.3-1.3) after controlling for potential confounding variables. This association was persistent when only patients with both gastric cancer and chronic gastritis were considered as cases and patients with CAG were considered as controls (OR = 0.7, 95% CI: 0.3-2.0) in the multivariate analysis. Our results suggest that H. pylori infection may be involved in the early stage of development of CAG, but not in the development of stomach cancer from CAG, and indicate that strategies for prevention of stomach cancer should target the early stage to eliminate H. pylori infection in high-risk populations.

The effects of vitamin E on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acetyltransferase (NAT) activities with 2-aminofluorene (2-AF) and p-aminobenzoic acid (PABA) were determined in the bacterium Helicobacter pylori. Cytosols or suspensions of H. pylori, with or without specific concentrations of vitamin E co-treatment, showed different percentages of 2-AF acetylation. The data indicated that there was increased NAT activity associated with increased levels of vitamin E in H. pylori cytosols and intact bacteria. For the cytosol and intact bacteria examinations, the apparent values of Km and Vmax were increased when vitamin E was added to the reaction mixtures for 2-AF and PABA acetylation, respectively. This report is the first demonstration to show that antioxidant agents (vitamin E) can promote H. pylori N-acetyltransferase activity.

Inhibitory actions of sulindac on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acetyltransferase (NAT) activity in Helicobacter pylori was inhibited by sulindac, a drug proposed for cancer prevention. The NAT activity was determined using an acetyl CoA recycling assay and HPLC. Inhibition of growth studies from H. pylori demonstrated that sulindac elicited a dose-dependent bactericidal effect in H. pylori cultures, that is, the greater the concentration of sulindac, the greater the inhibition of growth of H. pylori. The IC(50) value was 4mm for inhibition growth of H. pylori. Cytosols or suspensions of H. pylori with and without selected concentrations of sulindac co-treatment showed different percentages of 2-aminofluorene and p-aminobenzoic acid acetylation. The data indicated that there was decreased NAT activity associated with increased sulindac in H. pylori cytosols and intact cells (IC(50) values were 4mm). For the cytosol and intact bacteria examinations, the apparent values of K(m) and V(max) were decreased after co-treatment with 4mm sulindac. This report is the first demonstration of sulindac inhibition of arylamine NAT activity and sulindac inhibition of growth in the bacterium H. pylori.

Tea polyphenol intake and changes in serum pepsinogen levels

Following a phase I study, a phase II study was conducted to evaluate the effects of two different doses of tea polyphenols on serum pepsinogen levels. Subjects were patients aged 40 to 69 years who had undergone gastroscopy between 1995 and 1997 at Aichi Cancer Center Hospital, and had been found to have no disease requiring medication. Those with pepsinogen I < 70 ng/ml and pepsinogen I/II ratio < 6 were included in this study. Capsules containing 100 mg of tea polyphenols were administered for 1 year: 1 capsule per day for 101 patients (42 males and 59 females), and 6 capsules (equivalent to 10 cups) per day for 83 patients (30 males and 53 females). The enrollment of the 1 capsule group preceded that of the 6 capsule group, in which re-participation was allowed. Blood samples were obtained 1 year after participation from 86 participants of the 1 capsule group and 77 participants (43 new participants and 34 re-participants) of the 6 capsule group. The compliance in polyphenol capsule intake ranged from 11.4 to 105.7% (87.6% on average) of the scheduled amount for the 1 capsule group and 3.2 to 112.3% (77.8% on average) for the 6 capsule group. No serious polyphenol-related adverse effects were reported. The difference in pepsinogen I between before and after 1 year intake of the polyphenol was 3.1 ng/ml for the 43 participants of the 6 capsule group, but 3.5 ng/ml for the 1 capsule group. The mean pepsinogen I/II ratio for the 43 participants increased from 2.37 by 0.08. This increase was not larger than that for the 1 capsule group (from 2.61 by 0.11). Among 34 participants in both interventions, no significant increase in pepsinogen I and I/II ratio for the 6 capsule intervention was observed. This result suggests that additional polyphenol intake for 1 year in Japanese does not improve pepsinogen levels, which are considered to reflect stomach atrophy, a high-risk condition for stomach cancer.

Effects of garlic compounds diallyl sulfide and diallyl disulfide on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acctyltransferase (NAT) activities with p-aminobenzoic acid (PABA) and 2-aminofluorene (2-AF) were determined in the bacterium Helicobacter pylori collected from peptic ulcer patients. Two assay systems were performed, one with cellular cytosols, the other with intact cell suspensions. Cytosols or suspensions of H. pylori with or without specific concentrations of diallyl sulfide (DAS) or diallyl disulfide (DADS) co-treatment showed different percentages of 2-AF and PABA acetylation. The data indicated that there was decreased NAT activity associated with increased levels of DAS or DADS in H. pylori cytosols and suspensions. Viability studies on H. pylori demonstrated that DAS or DADS elicited dose-dependent bactericide affects on H. pylori cultures. The data also indicated that DAS and DADS decreased the apparent values of K(m) and Vmax of NAT enzyme from H. pylori in both systems examined. This report is the first demonstration that garlic components can affect H. pylori growth and NAT activity.

Inhibitory actions of glycyrrhizic acid on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acetyltransferase (NAT) activities with 2-aminofluorene (2-AF) and p-aminobenzoic acid (PABA) as substrates were determined in Helicobacter pylori, collected from patients with peptic ulcers. The NAT activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. Inhibition of growth studies from H. pylori demonstrated that glycyrrhizic acid elicited dose-dependent bactericidal effect in H. pylori cultures, i.e.; the greater the concentration of glycyrrhizic acid, the greater the inhibition of growth of H. pylori. Cytosols or suspensions of H. pylori with and without selected concentrations of glycyrrhizic acid co-treatment showed different percentages of 2-AF and PABA acetylation. The data indicated that there was decreased NAT activity associated with increased glycyrrhizic acid in H. pylori cytosols and intact cells. For the cytosol and intact bacteria examinations, the apparent values of Km and Vmax were decreased after co-treated with 80 M glycyrrhizic acid. This report is the first demonstration of glycyrrhizic acid inhibition of arylamine NAT activity and glycyrrhizic acid inhibition of growth in the bacterium H. pylori.

Correlation of ratio of serum pepsinogen I and II with prevalence of gastric cancer and adenoma in Japanese subjects

OBJECTIVE

Gastric cancer (GC) and adenoma (GA) are reported to be related to atrophic gastritis, in which the serum pepsinogen (PG) I level and the PGI/PGII ratio (I/II ratio) are reduced. To verify that the finding of a low PG level increases the risk for GC and GA, we investigated the correlation between low PG levels and the prevalence of GC and GA in individuals.

METHODS

The 2,039 subjects (734 Japanese men, mean age 68.5 yr, and 1,305 women, mean age 66.7 yr), selected from among 10,996 local residents who underwent health check-ups based on reductions in their serum PG levels, underwent upper gastrointestinal endoscopy.

RESULTS

Gastrointestinal endoscopy detected 21 GCs and 15 GAs. The prevalence of GC was higher than that in the residents without low serum PG. The percentage of early stage of GC (90%) was significantly higher than that of GC detected in unscreened residents (56.9%). The prevalence of GC in men was closely and significantly correlated with the I/II ratio (r = 0.935, p = 0.0063), whereas there was less correlation with age (r = 0.842, p = 0.0734). The prevalence of GA was also closely and significantly correlated with the I/II ratio in men (r = 0.881, p = 0.0203), but not with age (r = 0.163, p = 0.7928). In women the prevalence of GC (r = 0.744, p = 0.090) and GA (r = 0.678, p = 0.1392) did not correlate as strongly with the I/II ratio, although the highest prevalence was seen in the group with the lowest I/II ratio.

CONCLUSION

Our study verified that a low I/II ratio signifies a high risk for GC and GA and that measuring serum PG levels can be used as a screening method for GC and GA.

Lifestyle and anti-Helicobacter pylori immunoglobulin G antibody among outpatients

Since eradication of Helicobacter pylori (H. pylori) is thought to be a preventive measure against stomach cancer, several studies have examined factors associated with the infection. This paper reports the association of the infection with lifestyle factors observed in a hospital-based case-control study. Cases were 140 anti-H. pylori IgG antibody-positive outpatients (75 males and 65 females). Controls were 52 antibody-negative outpatients (22 males and 30 females). Both groups had undergone gastroscopy at Aichi Cancer Center Hospital between February 1995 and February 1997, and lifestyle data collected on the first visit were linked to calculate odds ratios. A strong association was observed with smoking among males; age-adjusted odds ratio (OR) = 7.85, 95% confidence interval (CI), 2.03-30.4. Rice breakfast (OR = 3.74; 95% CI, 1.30-10.8) and soybean paste soup (every day vs. occasionally, OR = 5.24; 95% CI, 1.80-15.2) were also associated with antibody positivity in males, but not in females. In females, pickled Chinese cabbage (> or = 1/week vs. < or = 3/month, OR = 2.82; 95% CI, 1.06-7.48) and lettuce (> or = 1/week vs. < or = 3/month, OR = 2.90; 95% CI, 1.09-7.76) were significantly associated with positivity. Multivariate analysis gave similar estimates for the above factors. Although the association between smoking and H. pylori infection has not been detected in past studies of a general population, except one recent one, this study on outpatients suggested a possible association. Smoking may work as a cofactor disturbing incidental eradication of H. pylori by antibacterial agents administered for other reasons.

Inhibitory actions of emodin on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acetyltransferase (NAT) activities with p-aminobenzoic acid and 2-aminofluorene were determined in Helicobacter pylori, a gram-negative rod bacteria collected from peptic ulcer patients. The NAT activity was determined using a acetyl CoA recycling assay and HPLC. Cytosols or suspensions of H. pylori with and without selected concentrations of emodin co-treatment showed different percentages of 2-aminofluorene and p-aminobenzoic acid acetylation. The data indicate that there were decreased NAT activity associated with increased emodin in H. pylori cytosols. As 400 microns of emodin can obviously inhibit NAT activity both in vitro and in vivo (inhibition rate 90% and 93% for 2-aminofluorene and p-aminobenzoic acid in vitro, and 90% and 92%, respectively, for both substrate in vivo). For in vitro examination, the apparent values of Km and Vmax were 3.12 +/- 0.38 mM and 15.20 +/- 3.16 nmol/min/mg protein for 2-aminofluorene, and 0.56 +/- 0.12 mM and 0.74 +/- 0.09 nmol/min mg protein for p-aminobenzoic acid. However, when emodin was added to the reaction mixtures, the values of apparent Km and Vmax were 2.40 +/- 0.32 mM and 10.62 +/- 0.04 nmol/min/mg protein for 2-aminofluorene, and 0.23 +/- 0.02 mM and 0.62 +/- 0.08 nmol/min/mg protein for p-aminobenzoic acid. For in vivo examination, the apparent Km and Vmax were 0.82 +/- 0.18 mM and 0.92 +/- 0.21 nmol/min/10 x 10(10) colony forming units (CFU) for 2-aminofluorene, and 0.78 +/- 0.14 mM and 0.52 +/- 0.06 nmol/min/ 10 x 10(10) (CFU) for p-aminobenzoic acid. However, when emodin was added to the reaction mixtures, the values of apparent Km and Vmax were 0.50 +/- 0.08 mM and 0.62 +/- 0.22 nmol/min/ 10 x 10(10) (CFU) for 2-aminofluorene, and 0.52 +/- 0.21 mM and 0.26 +/- 0.04 nmol/min/ 10 x 10(10) (CFU) for p-aminobenzoic acid. This report is the first finding of emodin inhibition of arylamine N-acetyltransferase activity in a strain of H. pylori.

Gastric cancer distal to the cardia--prevention or cure?

Adenocarcinoma of the stomach distal to the cardia remains one of the most common cancers in the world. The interest in the aetiology of this disease has been rekindled because of recent epidemiological and molecular studies linking this cancer to H. pylori and certain dietary factors. The authors provide an updated review of the aetiology of gastric cancer. This review seeks to summarize the disease, to propose pathways of carcinogenesis and to suggest ways in which the "traditional" risk factors may be interpreted on the basis of evolving knowledge.

Cancer, cigarette smoking and premature death in Europe: a review including the Recommendations of European Cancer Experts Consensus Meeting, Helsinki, October 1996

Cigarette smoking has been clearly and unambiguously identified as a direct cause of cancers of the oral cavity, oesophagus, stomach, pancreas, larynx, lung, bladder, kidney and leukaemia, especially acute myeloid leukaemia. Additionally, cigarette smoking is a direct cause of ischaemic heart disease (the commonest cause of death in western countries), respiratory heart disease, aortic aneurysm, chronic obstructive lung disease, stroke, pneumonia and cirrhosis and cancer of the liver. Cigarette smoking can kill in 24 different ways and, although smoking protects against several fatal and non-fatal conditions, the adverse effect of smoking on health is largely negative. In developed countries as a whole, tobacco is responsible for 24% of all male deaths and 7% of all female deaths: these figures rise to over 40% in men in some countries of central and eastern Europe and to 17% in women in the United States. The average loss of life of smokers is 8 years. Among United Kingdom doctors followed for 40 years, overall death rates in middle age were about three times higher among doctors who smoked cigarettes as among doctors who had never smoked regularly. About half of all regular cigarette smokers will eventually be killed by their habit. The important information is that it is never too late to stop smoking: among United Kingdom doctors who stopped smoking, even in middle age, there was a substantial improvement in life expectancy. World-wide, smoking is killing three million people each year and this figure is increasing. In most countries the worst is yet to come, since by the time the young smokers of today reach middle or old age there will be about 10 million deaths/year from tobacco. Approximately 500 million individuals alive today can expect to be killed by tobacco, 250 million of these deaths will occur in middle age. Tobacco is already the biggest cause of adult death in developed countries. Over the next few decades tobacco could well become the biggest cause of adult death in the world. For men in developed countries, the full effects of smoking can already be seen. Tobacco now causes one-third of all male deaths in middle age (plus one fifth in old age). Tobacco is a cause of about half of all male cancer deaths in middle age (plus one-third in old age). Of those who start smoking in their teenage years and keep on smoking, about half will be killed by tobacco. Half of these deaths will be in middle age (35-69) and each will lose an average of 20-25 years of non-smoker life expectancy. In non-smokers in many countries, cancer mortality is decreasing slowly and total mortality rapidly. The war against cancer is being won slowly: the effects of cigarette smoking are holding back this victory. Lung cancer now kills more women in the United States each year than breast cancer. For women in developed countries, the peak of the tobacco epidemic has not yet arrived. Tobacco now causes almost one-third of all deaths in women in middle age in the United States. Although it has only 5% of the world's female population, the United States has 50% of the world's deaths from smoking in women. Tobacco smoking is a major cause of premature death. Throughout Europe, in 1990 tobacco smoking caused three quarters of a million deaths in middle age (between 35 and 69). In the Member States of the European Union in 1990 there were over one quarter of a million deaths in middle age directly caused by tobacco smoking: there were 219700 in men and 31900 in women. There were many more deaths caused by tobacco at older ages. In countries of central and eastern Europe, including the former USSR, there were 441200 deaths in middle age in men and 42100 deaths in women. There is a need for urgent action to help contain this important and unnecessary loss of life. In formulating Recommendations, the European Cancer Experts Consensus Committee recognised that Tobacco Control depends on various parts of society and not only on the individual.

A randomized controlled trial for chemoprevention of gastric cancer in high-risk Japanese population; study design, feasibility and protocol modification

We have initiated a population-based, double-blind, randomized controlled trial to examine the effects of supplementation of beta-carotene and vitamin C on the incidence of gastric cancer. The subjects were participants in an annual health screening program conducted by four municipalities in Akita prefecture, one of the regions with the highest mortality from gastric cancer in Japan. We measured their serum levels of pepsinogens (PGs) I and II, and asked persons diagnosed with chronic atrophic gastritis (defined as PG I < 70 ng/ml and PG I/PG II ratio < 3.0) to take diet supplements containing 0 or 15 mg/day beta-carotene and 50 or 500 mg/day vitamin C for 5 years. During the first year of recruitment conducted in one village from June through September, 1995, 52% (635/1214) of screening participants had chronic atrophic gastritis and 73% (439/602) of eligible persons responded. However, in response to a National Cancer Institute press report released on January 18, 1996, indicating that two beta-carotene trials had shown no benefit and potential harm from the supplement, we discontinued the beta-carotene and continued with the trial using only vitamin C. Of 397 participants remaining at this point, 77% (305) consented to stay in the study. The results indicate that a randomized controlled trial for cancer prevention is feasible in the Japanese asymptomatic population.

Evidence for arylamine N-acetyltransferase activity in the bacterium Helicobacter pylori

N-Acetyltransferase activities with p-aminobenzoic acid and 2-aminofluorene were determined in Helicobacter pylori from gastroduodenal disease patients. The N-acetyltransferase activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. The N-acetyltransferase activities from a number of Helicobacter pylori samples were found to be 0.91 +/- 0.12 nmole/min/mg protein for the acetylation of 2-aminofluorene and 0.75 +/- 0.22 nmole/min/mg protein for the acetylation of p-aminobenzoic acid. The apparent K(m) and V(max) values obtained were 1.10 +/- 0.08 mM and 2.34 +/- 0.14 nmol/min/mg protein for 2-aminofluorene, and 0.92 +/- 0.09 mM and 2.08 +/- 0.16 nmol/min/mg protein for p-aminobenzoic acid. The optimal pH value for the enzyme activity was 6.0 for both substrates tested. The optimal temperature for enzyme activity was 37 degrees C for both substrates. The N-acetyltransferase activity was inhibited by iodacetamide: at 0.25 mM iodacetamide, activity was reduced 50% and 1.0 mM iodacetamide inhibited activity more than 90%. Among a series of divalent cations and salts, Cu2+ and Zn2+ were demonstrated to be the most potent inhibitors. Among the protease inhibitors, only ethylenediaminetetraacetic acid significantly protected N-acetyltransferase. Iodoacetic acid, in contrast to the other agents, markedly inhibited N-acetyltransferase. This is the first demonstration of acetyl CoA:arylamine N-acetyltransferase activity in Helicobacter pylori.

Vegetables, fruit, and cancer prevention: a review

In this review of the scientific literature on the relationship between vegetable and fruit consumption and risk of cancer, results from 206 human epidemiologic studies and 22 animal studies are summarized. The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon. The types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables, followed by allium vegetables, carrots, green vegetables, cruciferous vegetables, and tomatoes. Substances present in vegetables and fruit that may help protect against cancer, and their mechanisms, are also briefly reviewed; these include dithiolthiones, isothiocyanates, indole-3-carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, vitamin C, D-limonene, lutein, folic acid, beta carotene, lycopene, selenium, vitamin E, flavonoids, and dietary fiber. Current US vegetable and fruit intake, which averages about 3.4 servings per day, is discussed, as are possible noncancer-related effects of increased vegetable and fruit consumption, including benefits against cardiovascular disease, diabetes, stroke, obesity, diverticulosis, and cataracts. Suggestions for dietitians to use in counseling persons toward increasing vegetable and fruit intake are presented.

Mutagenicity of 24-hour duplicate of Japanese diet

In order to elucidate the genotoxicological characteristics of the Japanese diet, the mutagenicity of 24-h duplicate of the diet samples were investigated. The mutagenicity of blue rayon extract was examined in the Ames Salmonella/microsome assay. Thirty-two (91.4%) of 35 samples revealed mutagenicity toward Salmonella typhimurium TA98 in the presence of S9 mix. The mutagenic activities showed significant correlations with the consumption rates of broiled fish (r = 0.517, p = 0.0021) and broiled meat (r = 0.494, p = 0.0036). In other test conditions, 6 (17.1%), 5 (14.3%) and 8 (22.9%) samples were mutagenic to Salmonella typhimurium TA98 without S9 mix, TA100 with S9 mix and TA100 without S9 mix, respectively. Findings in the present study suggest that high consumption of broiled fish and broiled meat are important as the source of mutagens/carcinogens in the Japanese diet. In the present study, however, biological inference of these findings could not be made in relation to the occurrence of cancers, especially of the gastric cancer, which is the most prevalent form of cancer in Japan.

A pilot study for a randomized controlled trial to prevent gastric cancer in high-risk Japanese population: study design and feasibility evaluation

Observational epidemiological studies suggest that some nutrients reduce the risk of gastric cancer and that individuals with atrophic gastritis are at high risk of developing gastric cancer. One possible measure for gastric cancer prevention is therefore nutritional supplementation for the high risk group. Before recommending this strategy for the general public, however, a randomized controlled trial (RCT) is necessary. To evaluate the feasibility of an RCT, the authors conducted a pilot study using recipients of a health check-up program in a general hospital in Japan. The subjects who were asked to participate in the trial had been diagnosed as having atrophic gastritis on the basis of serum pepsinogen I < 70 ng/ml and the ratio of pepsinogen I to II < 3.0. They were requested to ingest double-blinded capsules containing different levels of vitamin C and beta-carotene every day. Out of the 219 subjects (118 males, 101 females) who were eligible for the study and had the required pepsinogen measurement, 90 (41%) met the criteria for atrophic gastritis. Among them, 55 (61%) (35 males, 20 females) gave their informed consent to participate in the RCT. Fifty-four participants completed a 3-month course of supplementation, and all of them agreed to a 5-year supplementation period. The authors concluded that an RCT using double-blinded nutritional supplements and targeting apparently healthy individuals is feasible in an intervention study for cancer prevention in Japan.

Protective factor against progression from atrophic gastritis to gastric cancer--data from a cohort study in Japan

To investigate the association between atrophic gastritis and gastric cancer and to identify the risk and protective factors for the progression of atrophic gastritis to cancer, we conducted a prospective study on 5,373 subjects with neither cancer nor resected stomach who underwent gastroscopic examination and completed a life-style questionnaire. After an average of 6 years of follow-up, 69 gastric-cancer cases were identified, 65 from the subjects without atrophic gastritis and 4 from the subjects without atrophic gastritis. The presence of atrophic gastritis increased the risk of gastric cancer 2.19-fold, the risk trend increasing with the degree and the extension of atrophy [relative risk (RR) 1.60 for mild atrophy and 2.85 for moderate and severe atrophy]. Among the subjects with atrophic gastritis, family history of gastric cancer (RR 2.27) and a preference for spicy food (RR 1.84) increased the risk and self-administered meal controls, such as portion reduction (RR 0.44) reduction of salty food (RR 0.56) and the change to the consumption of easily digested food (RR 0.57) decreased the risk of gastric cancer. The results of this study suggest that atrophic gastritis increases the risk of gastric cancer but that dietary modification prevents the progression from atrophic gastritis to gastric cancer, regardless of pre-cancerous lesions.

Epidemiologic data on alcoholic beverage consumption and risk of cancer

Recent epidemiologic data confirm the results of earlier studies in supporting that alcoholic beverage consumption is a cause of cancer of the mouth, pharynx, larynx, esophagus, and liver. The effect of a specified level of alcohol intake on absolute risk of cancers of the head, neck, and esophagus depends on the presence of other risk factors, especially smoking. Whether alcoholic beverage consumption is a cause of cancer of the breast or large bowel is unclear. Alcohol intake appears not to increase risk of cancer of the lung, bladder, prostate, stomach, ovary, endometrium, or of melanoma. Indirect epidemiologic evidence suggests that alcohol may be a weak causal factor for pancreatic cancer. Although heavy alcohol consumption increases risk of cancer of the head, neck, esophagus, and liver, whether moderate alcohol consumption increases risk at these sites is unclear.

Sensitivity and specificity of mass screening for gastric cancer using the measurment of serum pepsinogens

The aim of this study was to estimate the validity of mass screening for gastric cancer using serum pepsinogens (PG test). The study subjects were 4876 workers aged from 40 to 61 years old. Sera were obtained at the time of the health checkup and serum pepsinogen levels (PG I and PG II) were measured at the same time. PG I < 50 ng/ml and PG I/PG II ratio < 3.0 were adopted as the criteria for a positive result for the PG test. PG test-positive subjects were examined, in principle, by endoscopy. Furthermore, all subjects were followed up for a year to check for occurrence of gastric cancer. Among the total subjects, 911 (18.7%) were positive for the PG test and 650 (71.4%) among the positive subjects underwent further examinations, which revealed 11 cases of gastric cancer. Seven gastric cancer cases were diagnosed during the follow-up period within one year after the PG test. When the results of one years's follow-up from the time of screening were defined as the gold standard, the sensitivity and specificity of the PG test were estimated at 66.7% and 81.5%, respectively. The authors conclude that the validity of the PG test as a mass screening method may be comparable to that of X-ray screening, if optimum criteria of a positive test are selected.

Seroepidemiology of gastritis in Japanese and Dutch working populations: evidence for the development of atrophic gastritis that is not related to Helicobacter pylori

Serological markers of gastritis, like pepsinogen A, pepsinogen C, gastrin, and Helicobacter pylori antibodies, can be used to explore the state of the gastric mucosa in populations with contrasting cancer risks. A decreasing pepsinogen A:C ratio and an increasing serum gastrin are known to reflect an increasing severity of atrophic corpus gastritis, which is a precursor of gastric cancer. In 723 subjects (without gastroduodenal surgery) from Japanese (n = 225) and Dutch (n = 498) working populations, which had a similar composition of age (mean 48 years), sex (male to female ratio 6:1), and type of occupation, fasting serum samples were analysed for IgG antibodies to H pylori, pepsinogen A, pepsinogen C, and gastrin in the same laboratory. H pylori infection was significantly more prevalent in the Japanese than in the Dutch (74.7% and 31.3%); as was a very low pepsinogen A, indicative of severe mucosal atrophy (4.4% and 1.6%). Among subjects with and without severe mucosal atrophy the H pylori seropositivity rate was similar. Between the Japanese and the Dutch there were significant differences in mean gastrin (31.8 and 13.4 pmol/l) and pepsinogen A:C ratio (1.7 and 2.9). These intercountry differences were as great for H pylori negative subjects (gastrin: 23.7 and 10.3 pmol/l, pepsinogen A:C ratio: 2.4 and 3.2) as for H pylori positive subjects (gastrin: 34.6 and 20.1 pmol/l, pepsinogen A:C ratio: 1.5 and 2.5). The intercountry difference in gastrin nearly disappeared after stratification into categories of pepsinogen A:C ratio. In conclusion, the intercountry differences in pepsinogen A:C ratio and gastrin reflect a higher prevalence of mild and severe mucosal atrophy of the corpus in the Japanese than in the Dutch, both among H pylori positive and negative subjects. Thus, these findings suggest that in the Japanese the development of atrophic gastritis is in part unrelated to H pylori.

Alcohol consumption and risk of cancer in humans: an overview

Recent epidemiologic data continue to support alcoholic beverage consumption as a cause of cancer of the mouth, pharynx, larynx, esophagus, and liver. The effect of a given alcohol intake on absolute risk of these cancers depends on the prevalence of other risk factors. Whether alcoholic beverage consumption is a cause of cancer of the breast or large bowel is unclear. Alcohol intake appears not to increase risk of cancer of the lung, bladder, prostate, stomach, ovary, endometrium, or of melanoma. Indirect epidemiologic evidence suggests that alcohol may be a weak causal factor for pancreatic cancer. Additional research is needed to determine whether middle-aged women who drink moderately may experience a slight increase in longevity if they decrease alcohol intake. A number of biologically plausible mechanisms exist by which alcohol may cause cancer.

Detection of serum IgG antibody against Helicobacter pylori from childhood in a Japanese population

Epidemiological evidence has shown that seropositivity for Helicobacter pylori in the stomach is positively correlated with the incidence of gastric cancer. In this study, we investigated serum IgG antibody against H. pylori in asymptomatic Japanese subjects by an enzyme-linked immunoassay (ELISA) method (Serion, Wuerzburg, Germany). We noted two characteristics: (1) Seropositivity was seen in 41% of individuals aged less than 1 year, and in 9% of those aged 1-2 years, indicating the possibility that IgG antibody in infancy is derived from the mother. (2) Seropositivity was seen in 35% of individuals aged 15-19 years compared to 70% in those aged 20-24 years, indicating the spread of H. pylori infection with age.

Intestinal metaplasia of the stomach. A status report

Intestinal metaplasia in the stomach increases the risk of gastric cancer, and the increased risk is proportional to the extent of the metaplasia. This risk could be generated by one or more mechanisms: (1) the metaplastic tissue is an early step in a multistep induction process; (2) the metaplastic tissue is an epigenetic change that raises the pH of gastric juice by replacing oxyntic mucosa, favoring the growth of a bacteria capable of generating endogenous mutagens; and/or (3) the metaplasia is only a marker for chronic gastritis due to H. pylori infection or pernicious anemia. With the last mechanism, the inflammatory response favors intramural mutagenesis that might result in metaplasia or neoplasia as independent events. Finding gene rearrangements common to both metaplastic and neoplastic tissue may establish a direct link between them, but too few have been identified to account for the large number of stomach cancers that develop in high risk populations. Histochemical and immunochemical stains that identify enzymes or mucosubstances may suggest that metaplastic epithelial cells resemble small or large intestinal cells, but they are distinctly different from both. Moreover, these stains do not indicate whether a given cytologic change is genetic or epigenetic; therefore, they cannot be used to define the relationship between metaplasia and neoplasia. It is unnecessary for practicing physicians to await resolution of this question. It can be assumed that any person with extensive metaplasia is at high risk for gastric cancer and should be subject to periodic screening. The extent of the metaplastic process is probably more important than the metaplastic subtype.

Does high gastric cancer risk associated with low serum ferritin level reflect achlorhydria? An examination via cross-sectional study

With respect to the inverse association of serum ferritin level (SFL) with the risk of gastric cancer (GC) observed in some recent epidemiologic studies, possible mediation by achlorhydria as well as atrophic gastritis (AG), both of which are strongly associated with GC risk at not only the individual but also the population level, was examined in a cross-sectional study of 634 men aged 40 to 49 years randomly selected from 5 populations in Okinawa, Iwate, Nagano, Akita and Tokyo. AG and achlorhydria were serologically diagnosed based on the criteria of pepsinogen (Pep) I level < 70 ng/ml and Pep I/Pep II ratio < 3.0, as described previously, and a serum gastrin level of over 140 pg/ml, respectively. In the results, while the mean SFL for all the subjects differed significantly by area, similar areal differences in SFL were also found even when only the non-AG cases were considered. However, both of the above differences were eliminated with the exception of those between Okinawa and each of the other 4 areas, when adjustments were made for medical histories of diabetes mellitus, ulcers and liver disease, body mass index and gamma-glutamyltranspeptidase level. Therefore, no correlation among the 5 areas was observed between the adjusted areal mean SFLs and GC mortality in either case.(ABSTRACT TRUNCATED AT 250 WORDS)