摘要:

AbstractUrinary lignan and isoflavonoid excretion were examined in 11 men and 9 women consuming four nine‐day controlled experimental diets: basal (vegetable free), carotenoid vegetable (carrot and spinach), cruciferous vegetable (broccoli and cauliflower), and soy (tofu and textured vegetable protein product). Three‐day urine collections (Days 7–9) were analyzed for lignans and isoflavonoids with use of isotope‐dilution gas chromatography‐mass spectrometry. Urinary excretion of the lignans enterodiol and enterolactone was higher during the carotenoid and cruciferous vegetable diets than during the basal diet (p= 0.0001), suggesting that these vegetables may provide a source of mammalian lignan precursors. Urinary excretion of the isoflavonoids equol, O‐desmethylangolensin, daidzein, and genistein was higher when subjects consumed soy diets than when they consumed the other test diets (p<0.02). Gender differences in lignan excretion were observed. Men excreted more enterolactone (p= 0.006) and less enterodiol (p= 0.013) than women, implying a gender difference in colonic bacterial metabolism of lignans. There was no effect of gender on isoflavonoid excretion.

ISSN:0163-5581    

DOI:10.1080/01635589509514388

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractAlthough discovered as an exogenous agent of mammary carcinoma, the mouse mammary tumor virus (MMTV) is also transmitted vertically as endogenous proviral DNA present in the germ line of all inbred mice. In the C3Hf mouse, which receives no exogenous virus, the initial event of mammary tumorigenesis is the transcription of the endogenous MMTV proviral DNA present at theMtv‐1locus. Transcription occurs as a result of the hormonal effects of pregnancy, andMtv‐1specific transcripts are seen in second‐parity lactating mammary glands of these mice. As a means of studying the effects of diet on mammary carcinoma at the molecular/genetic level, we have studied the transcription of theMtv‐1locus in C3Hfmice on a high‐fat diet containing 46% fat in calories or a low‐fat diet containing 10% fat in calories. We have detected an accelerated transcription of theMtv‐1locus (first‐vs. second‐parity lactating mammary glands) in>50% of the C3Hf mice on the high‐fat diet. In addition, mice on the high‐fat diet developed mammary tumors earlier (11 vs. 17.8 mos) and after fewer litters (2.1 vs. 4.2). Our results indicate that fat in the diet can affect gene expression related to mammary carcinoma.

ISSN:0163-5581    

DOI:10.1080/01635589509514389

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractThe quantity ofβ‐carotene (BC) accumulated in colonic polyps and colonic cancererous tissue in humansin situwas determined relative to the quantity accumulated in normal colon and rectal tissue. Serum concentration of BC, retinol, andα‐tocopherol and tissue BC concentration were determined by high‐performance liquid chromatography in samples obtained before and after oral supplementation with BC (30 mg/day). The serum BC and retinol concentrations significantly increased in response to supplementation in control, polyp, and cancer patients, but there was no change in serumα‐tocopherol concentration. The BC concentration in tissue (colon, rectum, and tumor) of cancer patients was significantly less than that in tissue samples from control and polyp patients. Relative to baseline values, BC accumulated to a significant extent in tissues from all patients, including polyp and tumor tissue, during supplementation. The results indicate that BC does accumulate in colonic neoplastic tissue in humans and may potentially be utilized to augment cytotoxicity of chemotherapeutics or to prevent malignant transformation of cells.

ISSN:0163-5581    

DOI:10.1080/01635589509514390

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractIt has been reported thatγ‐linolenic acid (GLA)‐rich diets suppress mammary carcinogenesis and transplanted tumor growth and that GLA inhibits the growth of cultured human cancer cell lines. We compared the effects of dietary GLA and linoleic acid (LA) on the growth of MDA‐MB‐435 human breast cancer cells and their expression of the metastatic phenotypein vivoandin vitro. Athymic nude mice (30ldietary group) were fed isocaloric diets containing 20% (wt/wt) fat but providing 8% GLA or LA for 7 days, and 106tumor cells were then injected into a thoracic mammary fat pad. The diets were continued for a further 11 weeks.The primary tumor growth rates were similar in mice from the two dietary groups; there was a nonstatistically significant trend for the incidence of macroscopic lung metastases and the total lung metastatic volumes to be higher in the GLA‐fed mice (79% and 40.1±13.9 mm3) than in the LA‐fed mice (64% and 15.5±5.4 mm3). The tumor cell phospholipids from the 8% GLA‐fed mice contained significantly lower LA levels but higher arachidonic acid levels (bothp<0.001) than those from 8% LA‐fed mice. Also the arachidonate‐derived eicosanoids (prostaglandin E, leukotriene B4, and 5‐, 12‐, and 15‐hydroxyeicosatetraenoic acids) were significantly higher in tumors from the 8% GLA group. Zymography showed higher 92‐kDa type IV collagenase activity in tumors from 8% GLA‐fed mice.In vitro, GLA and LA, at 0.5–2μg/ml, stimulated MDA‐MB‐435 cell growth; 10μg/ml was mildly inhibitory. Whereas LA stimulated tumor cell invasion and 92‐kDa type IV collagenase productionin vitro, GLA inhibited invasion and did not induce activity of the proteolytic enzyme.Our results do not support the hypothesis that supplementation with GLA would exert a beneficial effect on the progression of an existing breast cancer, perhaps because it is metabolizedin vivoto arachidonate‐derived eicosanoids that are known to be involved in the metastatic process.

ISSN:0163-5581    

DOI:10.1080/01635589509514391

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractEpidermoid carcinomas were induced in hamster buccal pouches with use of 7,12 dimethyl‐benz[a]anthracene (DMBA). In five animals that served as tumor controls (Group 1), right buccal pouches were painted with DMBA (0.5% solution in mineral oil) thrice weekly for 14 weeks. In five animals (Group 2), right buccal pouches were painted with DMBA and reduced glutathione (GSH) was administered systemically by mouth. Five animals (Group 3) received vitamin E instead of glutathione. An additional 20 animals (Groups 4, 5, 6, and 7) were untreated, vehicle, glutathione, and vitamin E controls, respectively. Glutathione and vitamin E were given in doses of 10 mg/kg in 0.5 ml of mineral oil thrice weekly on days alternate to DMBA painting. Treatment by GSH and vitamin E reduced the number and size of tumors that were formed.Histopathologically, there were also fewer sites of dysplasia, carcinoma in situ, and early invasive epidermoid carcinoma than in the tumor control animals. The formalin‐fixed and paraffin‐embedded buccal pouch sections were stained immunohistochemically with use of monoclonal antibodies for cytokeratins. These included high‐molecular‐weight keratins (50,000–68,000 mol wt) 10, 13, and 8 (k10, k13, and k8, respectively). Oral carcinomas and dysplastic sites exhibited basal and suprabasal (spinous layer) high levels of k10, k13, and k8 staining. Treatment with GSH or vitamin E increased the suprabasal staining for high‐molecular‐weight keratins and reduced the protein expression for klO, k10, or k8. This pattern of staining was observed in dysplastic as well as in carcinoma sites. These results indicate that cytokeratin protein expression could contribute to a common biomarker analysis for chemoprevention.

ISSN:0163-5581    

DOI:10.1080/01635589509514392

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractPolyunsaturated fatty acids influence several steps involved in metastasis formation in animal tumor models. During the process of metastasis from the primary site, tumor cells adhere to the endothelium and underlying basement membrane before extravasation and secondary growth. The purpose of this study was to determine the effect of unsaturated fatty acids on adhesion of human breast cancer cell lines to components of the basement membrane. Cells were cultured in low‐serum medium for five days with or without added unsaturated fatty acids. Adhesion assays were conducted by incubating cells with basement membrane substrates coated on 96‐well plates, washing to remove nonadherent cells, and staining adherent cells with crystal violet. Linoleic acid (LA) and eicosapentaenoic acid increased adhesion of the metastatic cell line MDA‐MB‐231 to Matrigel and type IV collagen, while eicosapentaenoic acid decreased adhesion of the less metastatic cell line SK‐BR‐3 to these two basement membrane substrates. Oleic acid increased adhesion of MDA‐MB‐231 cells to Matrigel and fibronectin. Nordihydroguaiaretic acid and high concentrations of indomethacin, each of which inhibits the lipoxygenase pathway ofarachidonate metabolism, were effective in reversing the stimulatory effect of LA on MDA‐MB‐231 cell adhesion. A protein kinase C inhibitor likewise suppressed the increase in adhesion observed when MDA‐MB‐231 cells were incubated in media with added LA. Unsaturated fatty acids modified the adhesive properties of human breast cancer cell linesin vitro, and LA appeared to increase human breast cancer cell adhesion to extracellular matrix components by activating lipoxygenase and/or protein kinase C pathways.

ISSN:0163-5581    

DOI:10.1080/01635589509514393

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractSecondary bile acids (BA) may be involved in the pathogenesis of colorectal cancer.In vivo, starch malabsorption has been shown to reduce fecal excretion of secondary BA. The presentin vitrostudy was performed to investigate the effect of starch fermentation on BA metabolism by colonic bacteria. Fecal samples of healthy volunteers were incubated in anaerobic batch cultures for 48 hours with the primary bile acids cholic (0.6 g/l) and chenodeoxycholic acid (0.4 g/l). Media were starch free or enriched with starch (10 gll). The pH was controlled and held at 6 or 7.In the starch‐free incubations, secondary BA were rapidly formed, and degradation of primary to secondary BA was complete within 24 hours. The formation of secondary BA was partially inhibited by the addition of starch to the media. This effect was stronger at pH 6 than at pH 7. Starch was rapidly and completely fermented. In conclusion, this study showed that formation of secondary BA by fecal bacteria is inhibited when starch is simultaneously fermented, an effect that is mainly, but not completely, explained by reduction of pH.

ISSN:0163-5581    

DOI:10.1080/01635589509514394

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractThe potential involvement of individual fatty acids from diet or from adipose tissue in the outcome of cancer emphasizes the need for more insight into the relationship between fatty acids and tumor growth. The main objective of the present study was to examine whether rapid tumor growth would induce changes in the fatty acid composition of adipose tissue, indicating selective use and thus deposition of dietary fatty acids andlor selective removal of stored fatty acids from adipose tissue. We used a rodent model of transplanted solid tumor (Yoshida sarcoma) and measured the fatty acid composition from different adipose sites in the absence and in the presence of tumor but at the same intake of dietary fatty acids. We found that Yoshida sarcoma could grow rapidly without significantly altering the fatty acid composition of adipose tissue, irrespective of its location. These results do not favor the hypothesis of a selective removal of fatty acids from adipose tissue by growing tumors. They moreover indicate that tumors do not modify the storage of individual dietary fatty acids.

ISSN:0163-5581    

DOI:10.1080/01635589509514395

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

摘要:

AbstractThis study evaluates the reproducibility of food intake reports in a 45‐item self‐administered food frequency questionnaire (FFQ) used for a diet study in a large cohort in New York State. The first FFQ was mailed in 1980, and a followup version containing 75 food items was mailed in 1988 to the eligible original participants. Reproducibility was evaluated by comparing the subjects’1988 responses with their original 1980 responses. Spearman's correlations ranged from 0.27 (nuts other than peanuts) to 0.56 (summer squash) in men and from 0.25 (tomatoes) to 0.51 (summer squash) in women. Analyses stratified by age, education, marital status, body mass index, cigarette smoking, alcohol drinking, and special diet revealed few substantial differences in correlations. The moderate reproducibility of foods in this questionnaire indicates that brief FFQs may be a useful tool to study food intake and chronic disease relationships in this population.

ISSN:0163-5581    

DOI:10.1080/01635589509514396

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor

ISSN:0163-5581    

DOI:10.1080/01635589509514387

出版商:Taylor&Francis Group    

年代:1995

数据来源: Taylor