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We developed a method which we used in the current study to observe the rat colon endoscopically. Our goal was to evaluate the entire course in the development of experimental large bowel tumors through serial observations in the same rat. We compared the effects of dietary lard and cellulose on rat colon tumorigenesis in a 2 x 3 factorial design. Sprague-Dawley rats (n = 90) were divided into 6 diet groups: rats were fed a diet without cellulose that contained 5, 10, and 15 g/100 g lard, or diets containing 15% cellulose diet (15 g cellulose/100 g diet) and the same concentrations of lard. The development of large bowel tumors induced by the administration of 1,2-dimethylhydrazine (25 mg/kg body weight) for 19 wk was examined endoscopically. Tumor induction rates in the 15% cellulose groups were lower than in the 0% cellulose groups (P = 0.008), independent of the lard concentration. These results suggest that the preventive effect of cellulose against large bowel tumorigenesis is greater than the promotive effect of fat under the current experimental conditions.

We determined the levels of 15 elements in drinking water from 34 water treatment plants in Aomori Prefecture and studied how element levels relate to colorectal cancer incidence by district. Colorectal cancer incidence was calculated from the data of Aomori Colorectal Cancer Registry. Multiple regression analysis was performed by using age-adjusted incidences of rectal cancer and colon cancer by gender as object variables and each element level as an explanatory variable. The standardized partial regression coefficient was significant in gold (p

Epidemiological and experimental studies have shown that dietary fiber may prevent colon cancer. Resistant starch, like dietary fiber, is not subject to digestion in the small intestine. However, it is unknown whether resistant starch inhibits colonic carcinogenesis. In vitro studies have shown that butyrate slows the growth of cultured colon cancer cells. The effect of resistant starch diet on 1,2-dimethylhydrazine-induced colonic carcinogenesis in rats was evaluated, and the colonic butyrate concentration was measured.Sprague-Dawley rats were randomly divided into five groups that were fed diets containing no fiber, 3% cellulose, 10% cellulose, 3% resistant starch, or 10% resistant starch. Colonic carcinogenesis and butyrate concentration of colonic contents and feces in each diet group were compared.Total cancer volume per rat in the 10% cellulose group was significantly lower than that in the basal group (109 +/- 54 mm3 and 247 +/- 83 mm3; P0.05), but the other groups showed no significant differences. The butyrate concentration in colonic content and in feces were higher in the resistant starch groups than in the cellulose groups.The resistant starch diet increased butyrate concentration but did not inhibit colonic carcinogenesis. It remains doubtful whether butyrate inhibits the proliferation of colon cancer cells.

The per capita daily intake of dietary fiber (DF) in Japan between 1917 and 1991 was assessed using statistical reports regarding nutrition, food consumption, production, and trade balance. The reported contents of DF for each food category were used ; these values were based on the modified Southgate method and modified Prosky AOAC method. Average per capita daily consumptions of total DF calculated by the modified Southgate method were 30.3 g in 1917-1924 and 15. 6 g in 1991. Those calculated by modified Prosky AOAC method were 28.6 g in 1917-1924 and 14. 5 g in 1991. Both calculation methods yielded values indicating that the DF intake had been almost constant in the last 20 years. Differences in the calculated values of DF obtained by the two methods are attributed mainly to the difference in the measured values for rice. J Epidemiol, 1995; 5 : 205-210.

Based on the result of the Aomori Nutrition Survey, we have calculated daily dietary fiber (DF) intake using modified Southgate and Prosky methods. Result obtained were as follows: DF intake in Aomori was 23.7 +/- 8.4g by the modified Southgate method, and 22.2 +/- 8.5g by the modified Prosky method. As for supply sources of DF, 32.3% was from grains; 22.7%, vegetables; 15.6%, beans; and 7.8%, fruits calculated by the modified Southgate method, and 31.3%, vegetables; 19.0%, grains; 18.0%, beans; and 11.6%, fruits by the modified Prosky method. As to types of DF, intake of hemicellulose was 11.5 +/- 4.2g, cellulose 7.8 +/- 3.0g and lignin 4.4 +/- 2.3g. In the group with DF intake below 10.0g, DF came mainly from grains and fruits, while the group with DF intake above 30.0g took DF from various foods.

岩手県の一農村で便通,便性状と食品・嗜好品摂取状況との関連性を検討した,排便回数は,男性の88%が1目1回以上で女性の75%より有意に多かった.また男性は加齢とともに排便回数が少なくなる傾向にあった.自覚的便通では女性の便秘を自覚する割合が36%で男性の2倍であった.自覚的便の性状では女性で「兎糞」が11%と男性の4%より有意に多かった.便硬度は男女とも加齢とともに高くなり,さらに女性が男性より各年代とも有意に高い値を示した.一方,相対的便秘傾向に関する検討では,便通,便の性状に最も良好な影響を与える食品は米飯であった.またアルコールは全項目で相対危険度が1.0未満であったが,同時に下痢を助長する傾向が認められたため,便通,便の性状に良好な影響を与えるといえなかった.相対的下痢に対する相対危険度が全項目とも1.0未満であったのはつけものであった.

Colorectal cancer is thought to originate in colorectal adenoma and endoscopic polypectomy may prove prophylactic. To clarify the natural history of colorectal adenoma and the potential effects of endoscopic polypectomy, we retrospectively studied cohort patients undergoing full colonoscopies at 14 hospitals in Aomori Prefecture between January 1972 and December 1985. Subjects were divided into 3,574 non-adenoma controls and 1,020 adenoma patients, including 530 treated by polypectomy at initial examination. Subjects were followed up until the end of 1987 through record linkage with Aomori Colorectal Cancer Registry files to observe colorectal cancer occurrence. The ratio of observed number/expected number in the general population (O/E ratio) was 0.70 for the adenoma group and 0.36 for controls. The adenoma group was subdivided into polypectomy and non-polypectomy subgroups, with the O/E ratios of 0.39 for polypectomy patients and 0.75 for non-polypectomy patients. The O/E ratio in the adenoma group was about twice in controls, and this ratio in the nonpolypectomy subgroup was also about twice in thepolypectomy subgroup. The results suggest that colorectal adenoma provides a precancerous lesion that can be treated prophylactically by endoscopic polypectomy.

Even though it is important in improving the quality of life to evaluate the long-term prognosis of patients with ulcerative colitis in comparison with the general population, it is unknown in detail. One hundred and seventeen cases followed-up for 10 years or more were evaluated to define the long-term prognosis of ulcerative colitis by the person-years method. The estimated number of death (E) was 14.5, and the observed number of death (0) was 20. The O/E ratio was 1.38 and confidence interval was 0.84-2.13, showing no significant difference between E and O. Evaluation of change in th O/E ratio at 5-year intervals revealed a decrease in both the males and females, with a significant difference observed between the ratios in 1960 and 1965 (each p

MUNAKATA, A., NAKAJI, S., TAKAMI, H., NAKAJIMA, H., IWANE, S. and TUCHIDA, S. Epidemiological Evaluation of Colonic Diverticulosis and Dietary Fiber in Japan. Tohoku J. Exp. Med., 1993, 171(2), 145-151 - The incidence of colonic diverticulosis was examined in 5 hospitals geographically isolated from each other in Japan during the period between mid '70s and 1986. The incidence rapidly increased in all hospitals from 3.5-9.0% in mid '70s to 8.4-23.2% in 1986. The ratio of right-sided type colonic diverticulosis was approximately 70-80% in each hospital and the ratio did not fluctuate significantly during the period. Birth cohort analysis revealed that although the incidence of right-sided diverticula had increased with aging, in groups born in more recent decades right-sided diverticula appeared in younger age than other groups. It was suggested that environmental factors rather than congenital factors may cause the increase of the incidence of right-sided colon diverticula.

1972年から1986まで当科で診断した消化管憩室症例を検討した.15年間の各憩室の発見頻度は食道155例, 1.02%, 胃23例, 0.15%, 十二指腸601例, 3.94%, 大腸442例, 4.88%であった.十二指腸, 大腸憩室は年次別にみると増加 (P