摘要:

AbstractDietary guidelines posit an association between diet and cancer. Different cancer mortality rates among whites, blacks, and Hispanics may be related to differences in diet. Food frequency data from the 1987 National Health Interview Survey on 20,143 adults were used to estimate the percentage of adults, by gender and race/ethnicity, who consume some 59 foods six or more times per year, median number of servings for consumers, and frequency of consumption of skin on poultry and fat on red meat. On the basis of percent consumption of these foods, women appear to have a more diverse diet than men. Women eat more fruits and vegetables, less meat, and fewer high‐fat foods and drink fewer alcoholic beverages. Whites eat a more varied diet than blacks and Hispanics; blacks eat more fried and high‐fat food; consumption of high‐fat foods is lowest among Hispanics. Public health messages, especially those aimed at cancer prevention, should be targeted at increasing the overall consumption of fruits and vegetables, decreasing consumption of high‐fat foods, especially among white and black men, and increasing consumption of those healthful foods already consumed by particular race/ethnicity groups.

ISSN:0163-5581    

DOI:10.1080/01635589509514367

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractEllagic acid and 12 related agents have been tested for their ability to inhibit the activities of human DNA topoisomerase (topo) I and II. Using specific in vitro assays, we found ellagic acid and flavellagic acid to be potent inhibitors of the catalytic activities of the two topoisomerases. The minimum concentration required to inhibit≥50% of catalytic activity (IC50) of ellagic acid was determined at 0.6 and 0.7μg/ml for topo I and topo II, respectively. Flavellagic acid's IC50was determined at 3.0 and 3.6μg/ml for topo I and topo II, respectively. Unlike topoisomerase poisons, these two plant phenols did not trap the enzyme‐DNA reaction intermediate, known as the cleavable complex. In contrast, ellagic acid prevented other topo I and topo II poisons from stabilizing the cleavable complex, suggesting that the mode of its action is that of an antagonist. Structure‐activity studies identified the 3,3'‐hydroxyl groups and the lactone groups as the most essential elements for the topoisomerase inhibitory actions of plant phenols. On the basis of these findings and other properties of ellagic acid, a mechanistic model for the documented anticarcinogenic effects of the agent is proposed.

ISSN:0163-5581    

DOI:10.1080/01635589509514368

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractDietary phytoestrogens have been implicated in infertility among ruminants and may relate to human breast cancer risk. Formononetin is an isoflavonoid phytoestrogen found in animal fodder and in certain human foodstuffs. To investigate a possible mechanism by which phytoestrogens might influence mammary carcinogenesis, this study examined the capacity of formononetin to stimulate mammary gland proliferation. Formononetin was administered to castrated female BALBIc mice by daily subcutaneous injection; then mammary gland proliferation and estrogen receptor expression were quantified, and plasma prolactin levels were measured. A preliminary dose‐finding study demonstrated an estrogenic effect on vaginal cytology when formononetin was injected at 40 mg/kg sc. Peak plasma concentrations of 2.5±0.8 (SD)μg/ml at two hours and peak mammary tissue concentrations of 2.0±0.2 ng/mg tissue at four hours were noted after a single injection at this minimally bioactive dose. Among animals treated with formononetin at 40 mg/kg/day for five days, mammary gland proliferation was enhanced 3.3‐fold over saline‐treated controls and was comparable to that of animals treated with estradiol‐17βat 1μg/kg/day for five days. Mammary tissue estrogen receptor expression was 2‐fold higher among the formononetin‐treated animals (P<0.01 vs. saline‐treated controls), and plasma prolactin concentrations were increased 1.7‐fold (P<0.001 vs. saline‐treated controls). In subsequentin vitrobinding studies, formononetin competitively bound murine mammary estrogen receptors, but with a relative binding affinity 15,000 times less potent than that of estradiol‐17β. The results demonstrate an ability of formononetin to support mammary gland proliferation. However, the estrogenic potency of formononetin appears extremely weak compared with that of estradiol‐17βand is roughly proportional to estrogen receptor‐binding capacity.

ISSN:0163-5581    

DOI:10.1080/01635589509514369

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractExcess weight near the time of diagnosis is a well‐established risk factor for endometrial cancer; less is known about the influence of weight at earlier periods of a woman's life or weight gain in adulthood In a case‐control study in western New York State, interviews were conducted with 232 incident endometrial cancer cases, diagnosed between 1986 and 1991, and 631 community controls. Body mass index at 16 years of age and 20,10, and 2 years before interview and changes in body mass index between these time periods were examined. While being relatively heavy at 16 years of age was associated with slightly increased risk [adjusted odds ratio (OR) = 1.28, 95% confidence interval (CI) = 0.84–1.96], large gains over the entire period from 16 years of age to 2 years ago (OR = 3.45, CI = 2.13–5.57) and high body mass index close to the time of diagnosis (OR = 3.21, CI = 2.01–5.15) were associated with greater risk. Differences in mean body mass index between cases and controls increased over time.

ISSN:0163-5581    

DOI:10.1080/01635589509514370

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractThe present study was undertaken to investigate certain dietary factors known to affect the development of colon cancer for their ability to modulate aberrant crypt foci (ACF). Male Wistar rats were initiated with oral doses of dimethylhydrazine dihydrochloride (DMH‐2HCI, 20 mg/kg body wt) once a week for 10 or 20 weeks. Throughout the study the animals were fed 1) semisynthetic casein‐based control diet, 2) control diet with 20% lard, 3) control diet with 20% lard and 20% dietary fiber, or 4) control diet where most of the carbohydrate pool was substituted with sucrose and dextrin. The composition of the different diets was designed to achieve equivalent intakes of essential nutrients. Animals were killed after 10, 20, and 31 weeks.The study showed a pronounced effect of dietary composition on the development of DMH‐induced ACF. The diet high in sucrose and dextrin caused a statistically significant increase (p≤0.05) in the total number of ACF and number of small and medium A CF. Adding lard to the standard diet did not cause an increase in ACF, but if the dietary fiber was added to the high‐fat diet, a statistically significant reduction (p≤0.05) in the total number of ACF and number of small and medium ACF was observed. The values of large and extra‐large foci reflected the same effect of diets on ACF.The results indicate that tumors in the group fed the diet high in refined carbohydrates were more prominent and occurred with a higher incidence. However, the difference is based on few tumors and is not statistically significant. Our results do not show that the number of ACF and crypt multiplicity are conclusively predictive for tumor outcome with the present protocol, which did not include parameters to differentiate between ACF at the cellular level.

ISSN:0163-5581    

DOI:10.1080/01635589509514371

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractDietary fat intake has been associated with the development of chronic diseases, including heart disease and cancer, in human populations; however, associations demonstrated between disease and fat intake may be confounded by related dietary factors. Therefore, description of the correlates of fat intake in free‐living adults may help identify important confounders independent of disease status. In a population of 863 women and 538 men between the ages of 50 and 85 randomly selected from two counties in western New York, we found that most nutrients were correlated with grams of total fat intake including protein, carbohydrates, cholesterol, dietary fiber, retinol, iron, and calcium. Carbohydrates and dietary fiber were not related to the concentration of fat in the diet (% of energy from fat). Alcohol intake was negatively associated with fat concentration for men but not for women. Particularly important for the study of cancers, the antioxidants carotene and ascorbic acid were negatively associated with fat concentration in the diet.

ISSN:0163-5581    

DOI:10.1080/01635589509514372

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractThe effect of carotenoids onin vitroimmunoglobulin (Ig) production by peripheral blood mononuclear cells (PBMNC) was examined by employing blood samples from adult volunteers and full‐term newborn babies (umbilical cord blood). Under carotenoid‐supplemented culture conditions, cells were stimulated by polyclonal stimulants, neoantigens, and a recall antigen (Ag), and IgM, IgA, and IgG levels in the culture supernatant were measuredβ‐Carotene and astaxanthin were used as representatives of carotenoids with and without vitamin A activity, respectively.Astaxanthin enhanced IgM production in response to T‐dependent Ag (TD‐Ag) anda T‐de‐pendent polyclonal stimulant. Astaxanthin also augmented IgG production in response to a recall Ag. IgA production without supplemental carotenoids was negligible for all stimuli. However, in carotenoid‐supplemented cultures, IgA production was significantly higher in response to a T‐dependent polyclonal stimulant than in unsupplemented cultures. IgM and IgA production was augmented at 10−8molli astaxanthin, whereas astaxanthin enhanced IgG production in response to a recall Ag at 10−10‐10−9molli. Similar enhancing actions of astaxanthin on IgM production were observed in cord blood mononuclear cells (CBMNC), although CBMNC produced less IgM than adult PBMNC.β‐Carotene did not have a significant effect on human Ig production. The carotenoid actions were not demonstrated under serum‐free culture conditions; serum is essential for solubilization of carotenoids. In summary, this study has shown for the first time that astaxanthin, a carotenoid without vitamin A activity, enhances human Ig production in response to T‐dependent stimuli.

ISSN:0163-5581    

DOI:10.1080/01635589509514373

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractType of diet influences toxic effects of the chemotherapeutic drug methotrexate (MTX) on the gastrointestinal tract (GI) tract. In this study, commercial enterai products containing various protein types were tested to determine whether they exacerbated or alleviated MTX‐induced GI toxicity in a non‐tumor‐bearing animal model receiving a single injection of MTX (20 mg/kg). Five enterai products containing casein or soy isolate in various forms as the primary source of protein were used. One casein‐based product also contained soy fiber. These diets were compared with a soy concentrate‐based diet and a casein‐based diet prepared by the authors. Each diet was fed to 10 rats for seven days before injection and seven days after injection. In animals fed soy isolate or hydrolyzed or intact casein without added soy fiber, food intake was<30% of pre‐MTX injection levels on Days 3 and 4 after injection. These animals also lost weight and had diarrhea. Rats consuming the casein‐based diet with fiber experienced some protection against MTX toxicity. Food intake only dropped to 63% of preinjection levels, weight was maintained, and no diarrhea occurred. Rats fed soy concentrate maintained food intake above 90% of preinjection levels, which was greater than all other groups at Day 3 and those receiving hydrolyzed or intact casein without fiber on Day 4 (p<0.05). Weight gain in the soy concentrate group was also different from that in groups fed hydrolyzed or intact casein without fiber (p<0.05). Rats consuming soy concentrate had no diarrhea. A second experiment was conducted to evaluate histological damage to the intestine when these diets were fed to animals injected with MTX. This experiment was conducted in the same manner as the first experiment, except animals were sacrificed on Day 3 after injection and samples were obtained from the jejunum. Crypt necrosis occurred in all groups except those consuming the soy concentrate diet or the enterai product containing soy fiber. Results indicate that soy concentrate is superior in alleviating MTX toxicity compared with commercial enterai products.

ISSN:0163-5581    

DOI:10.1080/01635589509514374

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractFeeding rats a semipurified diet containing casein as a protein source results in severe gastrointestinal (GI) toxicity when the chemotherapeutic drug methotrexate (MTX) is given. However, when soy concentrate protein is used in place of casein, rats are completely protected from toxicity. The purpose of this study was to determine whether soy protein was also protective against two other chemotherapeutic agents, 5‐fluorouracil (5‐FU) and cyclophosphamide (CY), which are routinely used in a multidrug regimen with MTX in a clinical setting. Three diets were tested; they consisted of a control complex diet (rat chow) and two semipurified diets containing casein or soy concentrate as the protein fraction given to non‐tumor‐bearing rats receiving a single injection of 5‐FU or CY at three different levels (Experiment I: 5‐FU: 100, 260, and 420 mg/kg; Experiment II: CY: 120, 180, and 240 mg/kg). Each diet was fed to seven rats for seven days before injection and seven days after injection. Food intake decreased at Day 3 in all groups receiving 5‐FU (35–90% reduction from preinjection level), with the greatest decrease associated with the group receiving the highest drug level. Animals fed the control diet ate consistently less than animals fed the other two diets regardless of the drug level. Intake was not significantly different between the casein and soy concentrate groups at any drug level. Animals gained weight on the low‐dose treatment regardless of diets. At 260 and 420 mg/kg 5‐FU, all diet groups lost weight, but the difference was significant only between the control and the two other diets (p<0.05). Diarrhea was absent in the casein diet groups, regardless of drug dose, and present in the other diet groups. Food intake decreased on Day 1 for all groups receiving CY. At any dose, the control diet group maintained a greater intake on Day 1 than the other two diet groups. The difference in intake was significant between the control and the two other diet groups at low dose, between the control and the casein diet groups at 180 mg/kg, and between the control and the soy concentrate diet groups at high dose (p<0.05). All animals lost weight regardless of diet and drug dose. A third experiment was conducted to evaluate histological damage to the intestine when these three diets were fed to animals injected with 420 mg/kg 5‐FU. This experiment was conducted in the same manner as Experiment I, except animals were sacrificed on Day 3 after injection to remove jejunal samples. Crypt necrosis and debris occurred in all groups receiving 5‐FU. Valus height was decreased in all groups, with a less reduction in the casein diet group, and the difference was significant with the 2 other diet groups (p<0.05). Results indicate that none of the three diets promoted significant protection against 5‐FU‐or CY‐induced toxicity.

ISSN:0163-5581    

DOI:10.1080/01635589509514375

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractAlthough there is general agreement that dietary calcium is protective against colon carcino‐genesis, considerable controversy exists on the relative efficacy of the counterion in calcium supplements. We therefore conducted a comparative study in rats of four forms of calcium supplementation (calcium phosphate, casein, lactate, and a 50:50 phosphate‐carbonate combination). The relative effects of these supplements on measurements of colon physiology, in vivo pH, fecal fat, individual bile acids, and in vivo cell proliferation were measured in the same animals. In contrast to results when amounts of calcium are varied, there was no effect of form of supplement on total fecal output or output of fecal fat. Calcium phosphate resulted in the most acidified cecal contents. Calcium phosphate and calcium casein resulted in lower fecal concentrations oflitho‐cholate and lower amounts of total fecal bile acids than supplementation with the calcium lactate or combination diets. In addition, rats fed calcium phosphate had lower concentrations of fecalβ‐muricholate than rats provided with the calcium combination supplement. In the proximal colon, calcium phosphate resulted in a significantly lower number of cells per crypt column and a lower labeling index than the calcium lactate diet. The position of the highest labeled cell was lower with calcium phosphate supplementation than with supplementation from the calcium combination or the calcium lactate diet. There was a highly significant correlation between the pH of cecal contents and labeling index in the proximal colon (r= 0.98,p= 0.003). The results suggest that calcium phosphate may inhibit colon tumor incidence more effectively than calcium lactate, because the calcium phosphate group had a lower colonic proliferative status than the calcium lactate group. Changes in the proliferative status of colonocytes are known to precede and accompany neoplasia.

ISSN:0163-5581    

DOI:10.1080/01635589509514376

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor