ISSN:0163-5581    

DOI:10.1080/01635588509513834

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractEpidemiological interview studies examining the association between vitamin A and cancer at various sites have been hampered by restricted time available for interview; consequently, studies have included varying lists of food items or broad food groups, thus making comparability of results difficult. To identify a standardized list of indicator foods that adequately assess total vitamin A intake, we examined the 24‐hour dietary recall of 13,201 adults who participated in the First National Health and Nutrition Examination Survey (NHANES I) from 1971 to 1974. Food items reportedly consumed were ranked by contribution to overall (aggregated) intake in various subpopulations by an index of vitamin A contribution, which reflected the frequency of consumption, portion size, and vitamin A concentration (IUs/100 g). A comparison of these ranks identified certain food items that had a relative contribution to vitamin A intake which varied by sex/race group, season of interview, age, or region of the country; income level had little effect on the food rankings. The top‐ranking 50 foods were sufficient to correctly classify 80%‐90% of the individuals into low‐, moderate‐, and high‐consumer categories. The major contributing foods for any subpopulation examined included both retinol (e.g., dairy products, liver) and carotenoid sources of vitamin A (e.g., certain fruits and vegetables) in addition to items (e.g., mixed tomato and cheese dishes) not included in earlier questionnaire studies. Recommendations are made for future questionnaires designed to assess vitamin A.

ISSN:0163-5581    

DOI:10.1080/01635588509513835

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractFour groups of weanling male Wistar rats (Groups A—D) received diethylnitrosamine (DEN, 40 ppm) in their drinking water for four weeks; after a recovery period of two weeks, they received (for the rest of the experiment) phenobarbital (PB, 500 ppm) added to a Torula yeast‐based diet containing 0.17 ppm of selenium. Dietary selenium (2 ppm), as sodium selenite, was given to Group B one week before and during DEN treatment, to Group C one week before and during PB treatment, and to Group D during the entire experiment. Groups A and E received the unsupplemented diet, whereas Group E was not treated with DEN or PB. Pair‐feeding conditions were used to minimize possible influences of differences in food intake and growth. Rats were killed at the 19th and 24th weeks after the experiment began. No significant differences were found in food and fluid intakes or in growth rates among the groups. Livers in Group E were histologically normal, whereas preneoplastic and neoplastic lesions were found in all other groups. In rats killed at the 19th and 24th weeks, the numerical and the volumetric densities of preneoplastic lesions did not differ significantly between all the groups. Similarly, the incidence of hepatocellular carcinomas only detected at 24 weeks was not significantly different between the groups. These results indicated that in this particular model of hepatocarcinogenesis, the dietary supplementation of 2 ppm of selenium did not modify the development of preneoplasia and carcinomas.

ISSN:0163-5581    

DOI:10.1080/01635588509513836

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThe effect of low‐fat and high‐fat diets on the induction of mammary carcinomas by 1‐methyl‐1‐nitrosourea (MNU) was studied in female Sprague‐Dawley rats. All rats were given MNU (25 mg/kg body wt) at 50 days of age. For the first 17 weeks after carcinogen administration, they were fed a purified diet containing either 5 or 20% fat incorporated into agar gel. Food intake was restricted, so that the amounts fed provided the same amount of net utilizable energy each day for both groups, regardless of the fat content of the diets. From 17 to 32 weeks, the diets were fed ad libitum. During the restricted feeding period, there was no significant difference in tumor incidence or in the number Of tumors detected between the groups. During the weeks in which animals were fed ad libitum, significantly more tumors appeared in the high‐fat group than in the low‐fat group. The data provide support for the hypothesis that consumption of a high‐fat diet can lead to an enhancement of mammary carcinogenesis. It appears, however, that diets must be consumed ad libitum for the stimulatory effect on tumor occurrence to be exhibited.

ISSN:0163-5581    

DOI:10.1080/01635588509513837

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThe effect of vitamin B6on the growth of B16 melanoma cells in vivo and in vitro was studied. B16 melanoma cells grown for three days in medium supplemented with 5.0 mM pyridoxine or 0.5 mM pyridoxal showed an 80% reduction in cell proliferation compared with control culture. Cells cultured for six hours in medium supplemented with 0.5 mM pyridoxal took up and incorporated 13 and 32% less [3H]thymidine, respectively, than did control cultures. A 17% reduction in [3H]glucose uptake was observed at this time point. When the incubation time was decreased to three hours, an inhibition of cellular uptake of [3H]thymidine (22%), [3H]uridine (14%), and [3H]glucose (15%) was observed; however, little or no inhibition in incorporation was detected. In in vivo studies, mice pretreated with pyridoxal for two weeks and then injected with B16 melanoma cells had a 62% reduction in tumor weight compared with controls at the end of a three‐week period. If tumors were first established in mice and then treated with pyridoxal for six days, a 39% reduction in tumor growth was observed. There were no differences observed in body weights or liver weights in any of the animal groups.These results indicate that supraphysiological doses of vitamin B6can inhibit the growth of B16 melanoma cells both in vitro and in vivo. The exact mechanism by which pyridoxal exerts its inhibitory effect was not ascertained, but experiments suggest that the vitamer may be acting on the plasma membrane to reduce precursor transport into the cell.

ISSN:0163-5581    

DOI:10.1080/01635588509513838

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractMale Sprague‐Dawley rats were maintained on a vitamin A‐deficient diet for a period of five weeks. At the end of that time, hepatic cytochrome P450levels in vitamin A‐deficient rats were 65% that of rats fed a complete diet. However, the hepatic rate of benzo[a]pyrene metabolism was significantly greater (2 times) in vitamin A‐deficient rats compared with those fed a complete diet. The pattern of metabolites separable by thin‐layer chromatography was similar in both groups of rats. Benzo[a]pyrene induced its own metabolism by a slightly greater amount in the vitamin‐sufficient rats, but it was not to the level of the deficient group, although the levels of cytochrome P450were still below those of the deficient rats. In discussing lung microsomes, benzo[a]pyrene pre‐treatment of deficient rats resulted in slightly elevated levels of cytochrome P450and a slightly greater rate of metabolism of benzo[a]pyrene compared with rats fed the complete diet.

ISSN:0163-5581    

DOI:10.1080/01635588509513839

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThe effect of dietaryLaminaria angustata(brown seaweed) on azoxymethane (AOM)‐induced intestinal carcinogenesis was studied in male F344 rats. Five‐week old rats were fed semipurified diets containing 0 and 10% seaweed. When the rats were 7 weeks old, all except the vehicle‐treated groups received weekly subcutaneous injections of AOM in normal saline for two weeks (20 mg/kg body wt/week). All animals were fed the experimental diets until the termination of the experiment, which was 28 weeks after the last AOM injection. The incidence (percent of animals with tumors) and multiplicity (tumors/ animal) of small intestinal tumors did not differ significantly between the control and seaweed groups. The incidence and multiplicity of colon adenomas along with the size of colon tumors were increased in rats fed the seaweed diet compared with those fed the control diet. Dietary seaweed had no major effect on the concentration of fecal bile acids; however, the concentration of fecal cholesterol and total neutral sterols was decreased in the seaweed group. These results suggest that dietary seaweed increases the risk for colon tumors.

ISSN:0163-5581    

DOI:10.1080/01635588509513840

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractA study was conducted to determine the incidence and extent to which anorexia, a decrease in spontaneous food intake, contributes to the occurrence of cancer cachexia. Data for ten male subjects with small cell carcinoma of the lung are reported for a five‐month period following diagnosis. Although body weights of the subjects at the time of diagnosis averaged less than 95% of the usual weight (weight 6 months prior to diagnosis), they were greater than 109% of the mean ideal weight. At five months, the mean weight (N = 8) was 88% of the preillness weight. From the time of diagnosis, there was a mean loss of 7.2 kg (15.8 lb). The urinary creatinine excretion was below the normal range, whereas the urinary urea nitrogen values were within the normal range. At the time of diagnosis, the mean triceps skin‐fold measurements were approximately 80% of the standard reference for males.During the five‐month period, the mean midarm muscle circumference determinations remained greater than 90% of the reference standard. The mean serum transferrin values were 10% or more below the reported lower range of normal, whereas the great majority of the serum albumin values were 3.0 gldl or above during the five‐month period. The mean caloric intake of 2,204 kcal at the time of diagnosis was only 86% of the estimated basal energy expenditure (BEE) times a factor of 1.5 used to account for moderate activity. Four months following diagnosis, the mean caloric intake had fallen to 1,702 kcal, only 67% of the BEE×1.5 (calculated from the weight at diagnosis). The findings provide evidence of a decline in spontaneous food intake, a small decrease in body fat, and a greater than 13% weight loss. The oral intake was less than adequate for any activity beyond the basal state. Decreased intake could account for most of the weight loss observed in the subjects.

ISSN:0163-5581    

DOI:10.1080/01635588509513841

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractThirty‐six young adult male and female Syrian hamsters were divided into four groups. Group 1 (N = 6) was treated with mineral oil. Group 2 (N = 12) was treated with 7,12‐dimethylbenz[a]anthracene (DMBA), Group 3 (N = 12) was treated with DMBA and 13‐cis‐retinoic acid (RA), and Group 4 (N = 6) was treated with RA only. The hamsters were treated three times a week for six weeks. When the DMBA‐treated animals were also treated with RA, tumor formation was inhibited. In the DMBA‐treated animals that did not have RA, there was a significant reduction in the number of Langerhans cells (LCs) located interfocally and in foci compared with controls (p≤0.001). The systemic administration of 10 mg of RA significantly increased the number of ATPase‐positive LCs in the focal aggregates (p≤0.001). Interfocally, the number of ATPase‐positive LCs was statistically elevated in pouches from RA‐and DMBA‐treated animals (Group 2 vs. Group 3, p≤0.01). Following the administration of RA (Group 4), there was a statistically significant increase of LCs interfocally compared with Groups 2 or 3 (p≤0.001). RA administered alone resulted in a small increase in foci compared with Group 3 but in a significant decrease compared with the control group (p≤0.001). Systemic RA appears to not only affect the number of ATPase‐positive LCs but also to alter the distribution of these cells in DMBA‐treated pouches. The change in the number and relationship between LCs may effect the cell's ability to preserve local immunity.

ISSN:0163-5581    

DOI:10.1080/01635588509513842

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor

摘要:

AbstractSevere unrelenting weight loss appears to be a major component of the clinical picture seen in the patients with Acquired Immune Deficiency Syndrome (AIDS). Weight loss has been associated with a poor prognosis for AIDS patients with Kaposi's sarcoma. Strong evidence from a variety of clinical situations indicates that malnutrition per se adversely affects the cellular immune system and the susceptibility of individuals to infectious problems. In addition, weight loss of the degree commonly seen in the AIDS population places patients at risk of death because of resultant organ dysfunction. Moreover, severe weight loss may preclude recovery from infectious complications that otherwise would not represent a lethal challenge to the host. Because even appropriately directed therapies may not be successful when used in patients with severe weight loss, it is crucial to identify the mechanism of the weight loss associated with AIDS and to rapidly initiate evaluation of agents capable of altering or reversing this potentially lethal complication.

ISSN:0163-5581    

DOI:10.1080/01635588509513843

出版商:Taylor&Francis Group    

年代:1985

数据来源: Taylor