Effect of rice and salty rice diets on the structure of mouse stomach

Newly proposed quantitative criteria can assess chronic atrophic gastritis via probe-based confocal laser endomicroscopy (pCLE): a pilot study

Background and study aims  Probe-based confocal laser endomicroscopy (pCLE) can provide high magnification to evaluate chronic atrophic gastritis (CAG), but the current pCLE criteria are qualitative and prone to variability. We aimed to propose a quantitative CAG criterion based on pCLE to distinguish non-atrophic gastritis (NAG) from CAG. Patients and methods  This observational, exploratory pilot study included patients with NAG and CAG evaluated via esophagogastroduodenoscopy, pCLE, and histology. We measured the gastric glands density, gastric gland area, and inter-glandular distance during pCLE. Results  Thirty-nine patients (30/39 with CAG) were included. In total, 194 glands were measured by pCLE, and 18301 were measured by histology, with a median of five glands per NAG patient and 4.5 per CAG patient; pCLE moderately correlate with histology (rho = 0.307; P  = 0.087). A gland area of 1890-9105 µm ² and an inter-glandular distance of 12 to 72 µm based on the values observed in the NAG patients were considered normal. The proposed pCLE-based CAG criteria were as follows: a) glands density < 5; b) gland area < 1/16 the pCLE field area (< 1890 µm ² ) or > 1/4 the pCLE field area (> 9105 µm ² ); or c) inter-glandular distance < 12 or > 72 µm; CAG was diagnosed by the presence of at least one criterion. The proposed criteria discriminated CAG with a ranged sensitivity of 76.9 % to 92.3 %, a negative predictive value of 66.6 % to 80.0 %, and 69.6 % to 73.9% accuracy. Conclusions  The proposed pCLE criteria offer an accurate quantitative measurement of CAG with high sensitivity and excellent interobserver agreement. Larger studies are needed to validate the proposed criteria.

Dietary Factors and Gastric Intestinal Metaplasia Risk Among US Veterans

BACKGROUND

Studies on diet and gastric intestinal metaplasia (GIM) risk are lacking in US populations.

AIM

To determine the associations of dietary factors and risk of GIM among a US population with typical American diet.

METHODS

We analyzed data from a cross-sectional study of veterans attending primary care and endoscopy clinics at the Houston VA Medical Center. Patients completed a 110-item Block Food Frequency Questionnaire then underwent upper endoscopy with gastric mapping biopsies. We compared cases defined by GIM on ≥ 1 non-cardia gastric biopsy to controls without GIM. Associations of dietary factors and GIM were estimated using logistic regression models as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Among 423 GIM cases and 1796 controls, cases were older (62.1 vs. 59.9 years) and more likely to be male (97.2% vs. 90.8%) and non-White (58.6% vs. 39.0%). GIM cases had lower fat intake (percent kcal from fat tertile 1: 43.6% vs. 33.4%) and higher carbohydrate intake (percent kcal from carbohydrate T3: 41.8% vs. 33.3%) than controls. Adjusting for age, gender, race, smoking, and Helicobacter pylori, percent kcal from carbohydrates (T3 vs. T1: OR 1.35, 95% CI 1.08-1.67), fruit intake (T3 vs. T1: OR 1.28, 95% CI 1.02-1.61), and fiber intake (T3 vs. T1: OR 1.37, 95% CI 1.04-1.80) were associated with GIM. In subgroup analyses, these associations were primarily seen in non-White patients.

CONCLUSIONS

Few dietary factors, including high carbohydrate intake, are associated with increased risk of GIM in US populations, independent of H. pylori or smoking.

Recapitulating Human Gastric Cancer Pathogenesis: Experimental Models of Gastric Cancer

This review focuses on the various experimental models to study gastric cancer pathogenesis, with the role of genetically engineered mouse models (GEMMs) used as the major examples. We review differences in human stomach anatomy compared to the stomachs of the experimental models, including the mouse and invertebrate models such as Drosophila and C. elegans. The contribution of major signaling pathways, e.g., Notch, Hedgehog, AKT/PI3K is discussed in the context of their potential contribution to foregut tumorigenesis. We critically examine the rationale behind specific GEMMs, chemical carcinogens, dietary promoters, Helicobacter infection, and direct mutagenesis of relevant oncogenes and tumor suppressor that have been developed to study gastric cancer pathogenesis. Despite species differences, more efficient and effective models to test specific genes and pathways disrupted in human gastric carcinogenesis have yet to emerge. As we better understand these species differences, "humanized" versions of mouse models will more closely approximate human gastric cancer pathogenesis. Towards that end, epigenetic marks on chromatin, the gut microbiota, and ways of manipulating the immune system will likely move center stage, permitting greater overlap between rodent and human cancer phenotypes thus providing a unified progression model.

No Correlation of Inflammation With Colonization of Helicobacter pylori in the Stomach of Mice Fed High-salt Diet

Background:

Previous studies on Helicobacter pylori infection in mice have contributed to better understanding of the pathogenesis of chronic gastritis and gastric carcinoma. The aim of this study was to evaluate H. pylori colonization and subsequent inflammatory responses in the stomachs of C57BL/6 mice depending on inoculation number and the presence of high-salt diet.

Methods:

Eighty-four female mice with 4 weeks age were used in this study. The infected mice were gavaged with H. pylori strain Sydney-1 (SS1), and the uninfected mice were dosed with vehicle. In each of these groups, half of the mice were fed ona basal diet (0.25% salt) and the other half were fed on a high-salt diet (7.5% salt). The infected mice were inoculated 4 or 5 times, and infection status and degree of inflammation were checked by culture and histopathology, respectively, after 4 weeks. Gastric mucosal myeloperoxidase and tumor necrosis factor-alpha were measured by ELISA.

Results:

The overall infection rate was 95.2%; the infection rate after 5 inoculations (100%) was greater than that after 4 inoculations (91.3%). However, no differences in the degree of inflammation were found between 2 groups. The bacterial density was also significantly increased in mice that were on the high-salt diet and had been inoculated 5 times, respectively. Mean neutrophil infiltration in the infected group was 1.7±0.6 (1, minimal; 2, mild; 3, moderate; 4, marked). However, the high-salt diet was not increase the inflammatory grade in the infected group. Gastric mucosal myeloperoxidase and tumor necrosis factor-alpha levels did not increased by the high-salt diet and increased the number of inoculation.

Conclusions:

In spite of well colonization of H. pylori in the stomachs of C57BL/6 mice, the degree of subsequent inflammation was irrelevant to high-salt diet and frequent (5 times) inoculations.

Dietary factors modulate Helicobacter-associated gastric cancer in rodent models

Since its discovery in 1982, the global importance of Helicobacter pylori-induced disease, particularly in developing countries, remains high. The use of rodent models, particularly mice, and the unanticipated usefulness of the gerbil to study H. pylori pathogenesis have been used extensively to study the interactions of the host, the pathogen, and the environmental conditions influencing the outcome of persistent H. pylori infection. Dietary factors in humans are increasingly recognized as being important factors in modulating progression and severity of H. pylori-induced gastric cancer. Studies using rodent models to verify and help explain mechanisms whereby various dietary ingredients impact disease outcome should continue to be extremely productive.

Gastric cancer and salt preference: a population-based cohort study in Korea

BACKGROUND

Although the incidence of gastric cancer is declining, it remains the most common cancer in Korea. There have been discrepancies in epidemiologic studies regarding a causal relation between highly salted food and the risk of gastric cancer.

OBJECTIVE

The aim of this study was to assess the effect of salt preference on the incidence of gastric cancer in Korean adults through a population-based, prospective cohort study.

DESIGN

Participants were Korean government employees, school faculty members, and their unemployed dependents, aged 30-80 y, who underwent health examinations between 1996 and 1997. In 2003, information on the gastric cancer incidence in these participants was obtained during the 6-7-y follow-up period. The final data analysis included 2,248,129 study subjects. The hazard ratio (HR) and 95% CI of the HR were estimated by using the Cox proportional hazards regression model.

RESULTS

The age-standardized incidence rates per 100,000 person-years for the overall total population, men only, and women only were 97.64, 136.03, and 52.90, respectively. The Cox proportional hazards regression model, with adjustment for possible confounding factors, showed evidence of an increased risk of gastric cancer with salt preference. The HRs were 1.10 (95% CI: 1.04, 1.16) and 1.10 (95% CI: 1.03, 1.17) for the overall total population and men only, respectively.

CONCLUSION

The current findings suggest that salt preference has a marginal positive association with a risk of gastric cancer.

Review article: How useful are the rodent animal models of gastric adenocarcinoma?

Gastric cancer is the second most common cause of cancer-related mortality world-wide. In most cases, it develops via the pre-malignant stages of atrophic gastritis, intestinal metaplasia and dysplasia, following Helicobacter pylori infection of susceptible individuals. A number of rodent models have recently provided valuable insights into the host, bacterial and environmental factors involved in gastric carcinogenesis. Wild-type rodents do not develop gastric adenocarcinoma, but early studies showed that the disease could be induced in several rodent species by chemical carcinogens. More recently, it has been demonstrated that gastric adenocarcinoma can be induced in Mongolian gerbils by H. pylori infection and in C57BL/6 mice by long-term H. felis infection. These models have allowed the importance of Helicobacter virulence genes, host factors, such as gender, strain and immune response, and environmental factors, such as dietary salt, to be explored. A number of transgenic mice with alterations in various pathways, including the immune response, gastrin biosynthesis, parietal cell development, growth factors and tumour suppressors, have also provided models of various stages of gastric carcinogenesis. One model that has proved to be particularly valuable is the hypergastrinaemic INS-GAS mouse, in which gastric carcinoma develops spontaneously in old animals, but the process is greatly accelerated by Helicobacter infection.

Gastric cancer: who is at risk?

Gastric cancer is a multifactorial disease. Helicobacter pylori infection, host genetic factors and dietetic factors play an important role in the development of gastric cancer. Individuals with a positive family history of gastric cancer and/or pro-inflammatory polymorphisms of the interleukin-1 and tumor necrosis factor A genes infected by H. pylori virulent strains (cagA-, vacA s1-, vacA m1- and babA2-positive) have the highest risk of gastric cancer development. Diets rich in salted and smoked food and poor in fresh fruit and vegetables favor gastric carcinogenesis. Genetic combined with bacterial and host genotyping may allow for the identification of patients at high risk of gastric cancer who can benefit from preventive eradication therapy.

Inhibition of vacuolation toxin activity of Helicobacter pylori by iodine, nitrite and potentiation by sodium chloride, sterigmatocystin and fluoride

The toxin VacA produced by Helicobacter pylori is an important determinant of virulence. VacA causes vacuolation of cultured cells such as HeLa cells. Iodine, nitrite, sodium chloride, thiocyanate and fungus toxin sterigmatocystin are universally present in nature and could possibly be related to carcinogenesis of the stomach. The present study was designed to examine the effects of the above-mentioned compound on VacA-induced vacuolation of HeLa cells, which was quantitated using the neutral red uptake assay. VacA-induced vacuolation was inhibited by BafA1 and NPPB. Formation of large vacuoles was inhibited in the presence of iodine, nitrite, but enhanced by sodium chloride, thiocyanate, fluoride and sterigmatocystin. Our results indicate that VacA toxin may interact with other gastric cancer risk factors present naturally in the environment, and suggest that those compounds may modulate the development of gastric cancer induced by H. pylori.

Stomach cancer incidence in Brazil: an ecologic study with selected risk factors

Contrary to many industrialized countries in which a sharp decline in stomach cancer incidence has been observed, Brazil still shows intermediate to high incidence rates. An ecologic analysis was performed to explore variables possibly associated with the development of stomach cancer. Cluster analysis, principal component analysis, and factor analysis were carried out with population data, including the following: stomach cancer incidence rates in the early 1990s obtained from population-based cancer registries in Porto Alegre, Campinas, Fortaleza, Belém, and Goiânia; and data from a Brazilian national survey on family expenditures (several diet consumption items and availability of home refrigerators) carried out in 1974-75. The results suggested that past availability of a home refrigerator, i.e. food preservation, may have played an important role in currently observed differences in stomach cancer incidence among the various populations studied in Brazil. Differences in living standards among populations in these cities also appear to have played an important role in the observed incidence differences.

Evaluation of the aetiological role of dietary salt exposure in gastric and other cancers in humans

The findings in laboratory and epidemiological studies relevant to the assessment of salt for carcinogenic potential are reviewed. Associations between the high consumption of certain highly salted foodstuffs, particularly in some oriental countries, and increased risk of cancer of the stomach do not incriminate salt per se. Some highly spiced foods contain potent genotoxic carcinogens, irrespective of whether they also contain salt. There is evidence in laboratory animals that high concentrations of salt may increase the incidence of gastric cancer caused by such carcinogens. This may well be attributable to a marked and sustained regenerative response in the gastric mucosa of laboratory animals chronically exposed to the cytotoxicity of hyperosmolar concentrations of salt, such a mitogenic response favouring the progression towards neoplasia. However, there is no laboratory evidence whatsoever to indicate that salt per se is a carcinogen for any site in the body; neither is there any reliable epidemiological evidence to indicate that dietary salt affects the incidence of gastric or other cancers. A particular problem in the interpretation of epidemiological studies is that the consumption of diets containing highly salted, spicy foods is often associated with low intakes of fruit and green vegetables, which contain cancer-protective antioxidants. In Western countries the incidence of cancer of the stomach has been falling for some 50 years. The consensus view is that this fall is attributable to improved food hygiene and increasingly available facilities for refrigeration. There are no grounds for supposing that the fall is attributable to a decreasing intake of salt. A high dietary salt intake does not necessarily entail exposure to salt in concentrations high enough to damage the gastric mucosa. The typical Western diet would not be expected to provide such high salt concentrations. It is concluded that there are no grounds for believing that a reduction in the average daily salt intake in the Western diet would have any effect on the risk of developing any form of cancer.

Câncer de estômago: fatores de risco

Há cinqüenta anos o câncer de estômago vem perdendo a importância em termos de morbi-mortalidade em países considerados de primeiro mundo. Isso não ocorre no Brasil. Os principais fatores de risco evidenciados a partir de estudos epidemiológicos em várias populações do mundo e associados a essa neoplasia são alguns padrões de dieta. Com a descoberta do papel carcinogênico das nitrosaminas e do potencial anti-oxidante da vitamina C, algumas das associações entre câncer gástrico e padrões de dieta passaram a ser parcialmente entendidas. Com a descrição da Helicobacter pylori em 1983 e as evidências da relação dessa bactéria com certos processos patológicos do estômago, alguns precursores do câncer gástrico, novos elementos foram agregados ao processo fisiopatológico dessa entidade. O conhecimento hoje adquirido sobre a fisiopatologia do câncer gástrico, mesmo que parcial, fornece perspectivas estimulantes para prevenção e diagnóstico precoce.

Epidemiology of precancerous gastric lesions

Research over the past several decades has revealed that the major subtype of gastric cancer (intestinal gastric cancer) is an end result of a multistage transformation of the gastric mucosa over many years and that this process is mainly determined by environmental factors. Epidemiologic studies on precancerous gastric lesions, including a large population-based study of the natural history and aetiology of precancerous gastric lesions conducted in Shandong, China, are reviewed.

Comparison of the anatomic distribution of stomach cancer and precancerous gastric lesions

The anatomic distribution of precancerous gastric lesions among 3,400 residents in Linqu, Shandong Province of China, was compared with the anatomic distribution of stomach cancer (SC) among 959 patients in Tokyo, Japan. The incidence of SC is high in both areas, and locations within the stomach of the precancerous and malignant lesions were classified using similar criteria. Chronic atrophic gastritis (CAG) affected 98% of the population in Linqu, with intestinal metaplasia (IM) the most severe diagnosis in 33% and dysplasia (DYS) in 20%. Neither the SC nor precancerous lesions were uniformly distributed in the stomach. Among the DYS 3% were along the greater curvature of the body, 15% along the lesser curvature of the body, 25% in the angulus, 22% along the lesser curvature of the antrum, and 34% elsewhere in the antrum. Among the SC the corresponding percentages were 2, 16, 28, 25 and 29. The similarity to the SC distribution increased gradually from CAG to IM to DYS, providing further evidence for the multistage progression of precancerous gastric lesions.

Diet modification and gastric cancer prevention

The relative strengths of the etiologic factors identified for gastric cancer are discussed. On the basis of available scientific data, it is recommended that dietary prevention of gastric cancer be based on attempts to reduce the ingestion of foods with a high content of salt and to increase the intake of fresh fruits and vegetables. Other identified etiologic factors offer promise and are being investigated but do not yet justify recommendation to the general public.

Dietary risk factors in intestinal and diffuse types of stomach cancer: a multicenter case-control study in Poland

A hospital-based, multicenter, case-control study has been performed in Poland covering 741 incident stomach-cancer cases (520 males and 221 females) and the same number of controls. All stomach-cancer diagnoses were evaluated for histologic type according to the Lauren criteria. Fifty-one percent were of the intestinal type, 35 percent of the diffuse type, and 8.5 percent of the mixed type. The frequency of consumption of individual food items and several food groups was analyzed and the association of various foods with stomach cancer risk was evaluated after controlling for sex, age, occupation, education, and residency. Increased consumption of sausages was related significantly to gastric cancer risk, whereas increased consumption of cheese products, nonwhite bread, vegetables, and fruit was associated with decreased risk. A particularly strong decrease in risk was associated with consumption of radishes and onions. When consumption of fruits and vegetables, sausages, nonwhite bread, and cheese were introduced simultaneously in a multivariate model, independent effects were found only for fruit and vegetables, sausages, and nonwhite bread. The use of table salt, the frequency of eating hot meals, and an irregular eating pattern were also associated with increased risk, while additional consumption of fruit between meals showed reduced risk. If a reduction in vegetable and fruit consumption took place after marriage, an increased risk for stomach cancer was found, whereas augmented consumption of these food items after marriage decreased the risk. Separate risk models were calculated for stomach cancer of the intestinal and diffuse types, but both histologic varieties showed the same pattern of associations with dietary risk factors.

The epidemiology of gastric cancer

The etiology of gastric carcinoma, especially its "epidemic" or "intestinal" type is reviewed. The prevailing etiologic hypothesis, based on the selective targeting of etiologic agents in different points of the chain of causation, is described. Support for the hypothesis is updated, based on descriptive and analytical epidemiologic studies as well as on recently obtained laboratory and experimental evidence. Primary and secondary prevention measures are briefly discussed.

Epidemiological research in stomach cancer: progress over the last ten years

In this paper the progress of epidemiological research in stomach cancer during 1980-1990 is reviewed in respect to regional variation, etiology, and formation of carcinogens. The evaluation of 4 cohort and 16 case-control studies revealed a consistently inverse relationship of stomach cancer risk with raw vegetables, fruit, and wholemeal bread consumption and with vitamin C and carotene intake. Milk, cooked vegetables and vitamins A and E were not consistently found to be related to stomach cancer risk. Positive associations of increasing consumption with stomach cancer risk were occasionally found for processed or particularly prepared meat and fish, and for nitrite. Dietary nitrate intake did not appear to be related to stomach cancer risk in these studies. This latter observation is also supported by metabolic studies in high- and low-risk areas for stomach cancer. Consistently among studies, increased risk for stomach cancer was also found for later availability of refrigeration facilities in the household, non-centralized water supply (especially well water), and high salt intake. Prospective studies agreed in an increased risk for stomach cancer for cigarette smoking, but not for alcohol drinking, whereas case-control studies showed divergent results on these factors. Recent metabolic studies in high- and low-risk areas for stomach cancer or in groups with precursor lesions, with the N-nitrosoproline test as a marker for endogenous nitrosation, revealed inconsistent results. Higher nitrite concentration and increased pH in stomach juice were found to be associated with precursor conditions for stomach cancer. It is still not clear whether intake of preformed carcinogens or endogenous formation in the stomach with or without the inclusion of nitrite is the most important source of tumor-initiating or -promoting substances. Preservation or preparation of meat and fish may play an important role in this process, and vitamin C may be an inhibiting substance.

Risk factors of gastric precancerous lesions in a high-risk Colombian population. I. Salt

A case-control study for stomach cancer was conducted in a high-risk population in Nariño, Colombia to determine the risk of gastric precancerous lesions associated with salt intake measured by sodium-to-creatinine ratio of a single urine sample. Gastric biopsies and urine samples were collected from 263 individuals. Urinary sodium-to-creatinine ratios were studied in relation to histological data from the biopsies. Significantly high odds ratios for precancerous lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia) were associated with higher sodium-to-creatinine ratios. Adjusted odds ratios (OR) of 2.50 for chronic atrophic gastritis and 7.24 for dysplasia were found. The association with intestinal metaplasia was weaker and not significant (OR = 1.57). Furthermore, an excess risk associated with adding salt to food at the table was found among patients with precancerous lesions (OR = 1.80). These findings support the two-step involvement of salt in the process of gastric precancerous lesions.

A case-control study of gastric cancer and diet in Italy

A case-control study was conducted in high- and low-risk areas of Italy to evaluate reasons for the striking geographic variation in gastric cancer (GC) mortality within the country. Personal interviews with 1,016 histologically confirmed GC cases and 1,159 population controls of similar age and sex revealed that the patients were more often of lower social class and resident in rural areas and more frequently reported a familial history of gastric (but not other) cancer. After adjusting for these effects, case-control differences were found for several dietary variables, assessed by asking about the usual frequency of consumption of 146 food items and beverages. A significant trend of increasing GC risk was found with increasing consumption of traditional soups, meat, salted/dried fish and a combination of cold cuts and seasoned cheeses. The habit of adding salt and the preference for salty foods were associated with elevated GC risk, while more frequently storing foods in the refrigerator, the availability of a freezer and use of frozen foods lowered risk. Reduced GC risk were associated with increasing intake of raw vegetables, fresh fruit and citrus fruits. Lowered risk was also related to consumption of spices, olive oil and garlic. Neither cigarette smoking nor alcoholic beverage drinking were significantly related to GC risk. The case-control differences tended to be consistent across geographic areas, despite marked regional variations in intake levels of certain foods. The high-risk areas tended to show higher consumption of food associated with elevated risk (traditional soups, cold cuts) and lower consumption of foods associated with reduced risks (raw vegetables, citrus fruits, garlic). Our findings indicate that dietary factors contribute to the regional variation of stomach cancer occurrence in Italy, and offer clues for further etiologic and prevention research.

Interaction between N-methyl-N'-nitro-N-nitrosoguanidine and 2 steroid hormones in the glandular stomach of mouse. I. Acceleration of hydrocortisone turnover by use of a salt-rich diet and the carcinogen

The present study has investigated the question of whether or not hydrocortisone as a gene regulator plays a role in the expression of carcinogenic and cocarcinogenic actions of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and NaCl at the gastric epithelium. The interaction of local hydrocortisone, MNNG and NaCl was studied in vitro and in vivo using Swiss/ICR mice of both sexes. MNNG inhibited specific hydrocortisone binding with the cytoplasmic receptor from the glandular stomach of mouse. The intake of both excess NaCl and MNNG induced an increase in hydrocortisone turnover in the glandular stomach of mouse. Likewise, administration of either excess NaCl or MNNG increased the activity of ornithine decarboxylase in the glandular stomach of mouse. Long-term use of a salt-rich diet and MNNG drink induced an irreversible reduction in water consumption without affecting NaCl consumption, a dissociation of the hydrocortisone effect. The aforementioned MNNG effect on water turnover was more marked in female than in male mice. It is suggested that NaCl and MNNG produce a state of corticosteroid stimulation and androgen depression at the glandular stomach epithelium of mouse--a reproduction of the hormonal markers of gastric cancer.

Interaction between N-methyl-N'-nitro-N-nitrosoguanidine and 2 steroid hormones in the glandular stomach of mouse. II. Retardation of local dihydrotestosterone turnover by use of a rice-rich diet and the carcinogen

We investigated the question of whether or not N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a gastrocarcinogen with a structural resemblance to the antiandrogenic gastrosuppressant cimetidine, had a similar antiandrogenic activity in the glandular stomach of mouse. Possible influence of a rice-rich diet on the interaction of androgen with the same tissue was also studied in relation to its gastrosuppressive effect. The results obtained were as follows: 1) excess MNNG non-competitively inhibited the specific binding of 3H-dihydrotestosterone (DHT) with the cytoplasmic receptor of the glandular stomach of mouse; 2) the MNNG intake slowed down local 3H-DHT turnover in the glandular stomach of mouse; 3) evidence was presented to indicate that MNNG action was antiandrogenic in nature; 4) a rice-rich diet, exerting a weight-decreasing influence on the glandular stomach, also slowed down the 3H-DHT turnover in the same tissue. It was indicated that both MNNG and a rice-rich diet produced a state of androgen depression in the glandular stomach of mouse by slowing down the turnover of local androgen and/or competing with local androgen for its receptor in the target tissue. The significance of the results was discussed in relation to the etiology of gastric cancer.

Effect of a rice-rich diet on the therapeutic efficacy of cyclophosphamide with special reference to the enhancement of transplantation immunity

The present study investigated the problem of whether the therapeutic efficacy of cyclophosphamide in the in vivo Ehrlich ascites tumor system can be improved by adjuvant use of hydrocortisone or of dietary hydrocortisone mobilizers. In the chemotherapy experiment, female ICR mice each received an inoculum of 1 x 10(6) cells of Ehrlich ascites tumor ip followed by 2 ip injections of cyclophosphamide 36 and 37 hr later (2.4 mg/mouse for the 1st injection, and 1.0 mg/mouse for the 2nd injection). The effects of both cyclophosphamide and adjuvant treatments were assessed in terms of either survival rate or cure rate in the 1-month experiment. The results obtained were as follows. 1) Prolonged use of hydrocortisone as an adjuvant can improve the survival of cyclophosphamide-treated mice. 2) Adjuvant use of a rice-rich diet for maintenance increased the rates of both survival and cure in the cyclophosphamide-treated mice. 3) The same maintenance of mice on a rice-rich diet increased transplantation immunity on the one hand, and induced a set of steroidal changes including hydrocortisone excess on the other hand. 4) Evidence is presented to indicate that the beneficial influence of a rice-rich diet on the drug effect is related to an increase of transplantation immunity in the host, and that there could be a causal relationship between hormonal and immunological changes in rice-saturated mice.

Hormonal status of gastric cancer. I. Effect of rice and salty rice diets on the constitution of urinary steroids in mice

We investigated the effect of rice and salty rice diets on the physical growth and on the constitution of urinary steroids in Swiss/ICR mice. The following three kinds of diets were employed in the feeding experiment: 1) standard diet; 2) rice diet; and 3) salty rice diet. Long-term maintenance of mice on both rice and salty rice diets led to a relative increase of tetrahydrocortisol associated with a concomitant decrease of androgen, progestin, and cholesterol in urine. Evidence was presented to indicate that the activity of endogenous hydrocortisone in mice could be augmented by an increased intake of sodium chloride alone; there was also evidence that the glandular stomach of a young mouse drinking physiological saline is highly sensitive to a suppressive action of hydrocortisone. We concluded that the two experimental diets produced a state of catabolic glucocorticoid excess combined with a deficiency of anabolic androgen and progestin. Mineralocorticoid status was not examined. In the salty rice diet, a markedly lower weight gain was observed, whereas in the rice diet, in general, no significant weight changes were observed.

Hormonal status of gastric cancer. II. Abnormal constitution of urinary steroids in gastric cancer patients

We undertook a case-control study regarding the excretions of 14 urinary steroids in gastric cancer (GC) patients. The results are as follows: the levels of androgens, progestins, and two corticosteroids were, relative to tetrahydrocortisol, significantly depressed in GC patients of both sexes compared with the corresponding normal controls. The deviation profile of urinary steroids was not affected by radical gastrectomy. Evidence indicated that observed changes of GC urines were the steroidal expression of a decrease of endogenous testosterone combined with an increase of endogenous hydrocortisone; there was also evidence that the hormonal environment of our GC patients was endocrinologically homologous to that of rice-fed or salty rice-fed mice. Epidemiological inquiry revealed that GC patients having more access to rice-rich or salt-rich diets were taller and less obese than were rural healthy controls. In agreement with the anthropometric data of those cancer patients is the finding that the specific death rate of GC (as calculated for each of 15 prefectures of northern Japan) was positively correlated for each sex with the mean heights, but not with the mean weights, of 14-year-old youths of those areas. This paper discusses the possible relevancy of the hormonal and epidemiological aspects of GC patients to gastrocarcinogenesis in light of steroid physiology.