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Biomedical subjects

A Engle

Publications and source records attributed to A Engle.

At least 19 recordsLinked to original sources
PubMed1999

Gender-related factors influencing perceptions of homosexuality.

There is a long history linking gender role conformity to perceived homosexuality. However, the lack of a systematic theoretical model hinders the elucidation of the interrelationships among gender stereotypes, conformity to gender stereotypes, and perceived homosexuality, as well as other factors which may mediate these relationships. The purpose of the present study was to propose such a model by combining theories of gender stereotype formation and maintenance with research investigating perceptions of homosexuality. Specifically, this study examined college students' perceptions of gender role characteristics in male and female adult target persons and these students' perceptions of the likelihood that the targets were homosexual. Path analysis demonstrated that the sex and occupation of the target person were significantly related to perceived masculinity, femininity, and homosexuality of the target person. Furthermore, individual differences in these relationships were observed, indicating that the sex and gender role characteristics of the participant influenced perceptions of the gender role attributes and homosexuality of the target person.

Adult↗
PubMed1995

Synthesis and structure-activity relationships of oxamic acid and acetic acid derivatives related to L-thyronine.

Aryloxamic acids 7 and 23, (arylamino)acetic acids 29, arylpropionic acids 33, arylthioacetic acids 37, and (aryloxy)acetic acid 41 related to L-triiodothyronine (L-T3) were prepared and tested in vitro for binding to the rat liver nuclear L-T3 receptor and the rat membrane L-T3 receptor. The structure-activity relationships for these compounds are described, with 7f, 23a, 29c, 33a, 37b, and 41 showing excellent potency (IC50's of 0.19, 0.16, 1.1, 0.11, 3.5, and 0.10 nM, respectively) to the nuclear receptor and significantly lower binding affinity to the membrane receptor (IC50's > 5 microM). Some of these compounds, especially in the oxamic acid series 7 and 23, showed an unprecedented potency for methyl-substituted derivatives such as 7f and 23a. Compounds 7f and 23a showed good lipid lowering effects in rats with ED50's of 20 and 5 micrograms/kg po, respectively, and a lack of cardiac side effects in rats at doses as high as 10 and 25 mg/kg po, respectively.

Acetates↗
PubMed1994

Biochemical epidemiology of colon cancer: effect of types of dietary fiber on colonic diacylglycerols in women.

BACKGROUND/AIMS: In view of the potential significance of dietary fat and fiber in colon cancer and the possible indirect involvement of diacylglycerols (DAGs) in the pathogenesis of colon cancer, the effect of types of dietary fiber on fecal DAG in premenopausal women was investigated. METHODS: Forty-eight women consuming a typical western diet provided two 24-hour stool specimens and two sets of preintervention 4-day food records. They were randomly assigned to one of the fiber groups, namely, a wheat, oat, or corn bran supplement. They consumed their control diet plus 13-15 g of dietary fiber from each source for 8 weeks. At the end of the fiber period, each subject provided two 24-hour stool specimens and 4-day food records. Stool samples collected during the two periods were analyzed for total fat and DAG fatty acids. RESULTS: All sources of dietary fiber increased the amount of fecal fat excreted. Dietary wheat bran decreased the concentrations of total DAG and DAG containing lauric acid, myristic acid, palmitic acid, stearic acid, and linoleic acid, whereas oat bran increased the DAG composed of oleic acid and linoleic acid compared with the control diet. Corn bran decreased the DAG containing stearic acid. CONCLUSIONS: These results show that the modifying effect of dietary fiber on DAG depends on the type of fiber consumed.

Adult↗
PubMed1992

Effect of dietary fiber on colonic bacterial enzymes and bile acids in relation to colon cancer.

Because of the potential significance of colonic bacteria and secondary bile acids in the pathogenesis of colon cancer, the present study investigated the effect of different types of dietary fiber on fecal bacterial enzymes, namely, beta-glucuronidase, 7 alpha-dehydroxylase, nitroreductase, and azoreductase, and on bile acids and neutral sterols in premenopausal women. The subjects consumed 13-15 g of wheat, oat, or corn bran daily for 8 weeks in addition to their normal diet. Stools collected during the normal and fiber diet periods were analyzed for the above constituents. Dietary wheat bran decreased the concentrations of fecal deoxycholic acid, lithocholic acid, 12-ketolithocholic acid, and neutral sterols and the activities of all bacterial enzymes. Oat bran had no effect on secondary bile acids and 7 alpha-dehydroxylase but decreased beta-glucuronidase, nitroreductase, and azoreductase levels. Dietary corn bran increased 7 alpha-dehydroxylase, lithocholic acid, and cholesterol levels and decreased deoxycholic acid coprostanol, cholestenone, nitroreductase, and azoreductase levels. These results show that the modifying effect of dietary fiber on secondary bile acids and bacterial enzymes that may play a role in carcinogenesis depends on the type of fiber consumed.

Adult↗
PubMed1991

Nutritional risk factors and ovarian cancer.

In a hospital-based case-control study, consumption of lactose-containing (dairy) foods and foods containing beta-carotene by 71 women with epithelial cancer of the ovary and 141 matched controls was investigated. No significant differences were found between cases and controls in the frequency of consumption of dairy foods or in the amount of lactose consumed. Consumption of carrots was found to decrease risk. Logistic regression analyses indicated a protective effect of high beta-carotene intake (odds ratio = 0.3, 95% confidence interval = 0.1-0.8), after adjusting for body mass, smoking, and lactose consumption.

Administration, Oral↗
PubMed1991

Diet and serum lipids in vegan vegetarians: a model for risk reduction.

The lipid levels and dietary habits of 31 Seventh-Day Adventist vegan vegetarians (aged 5 to 46 years) who consume no animal products were assessed. Mean serum total cholesterol (3.4 mmol/L), low-density-lipoprotein cholesterol (1.8 mmol/L), and triglyceride (0.8 mmol/L) levels were lower than expected values derived from the Lipid Research Clinics Population Studies prevalence data. Mean high-density-lipoprotein cholesterol (1.3 mmol/L) was comparable to expected values. Analysis of quantitative food frequency data showed that vegans had a significantly lower daily intake of total energy, percentage of energy from fat (31% vs 38%), total fat, saturated fat, monounsaturated fatty acids, cholesterol, and protein and a significantly higher intake of fiber than a sample of matched omnivore controls. Vegans' food intake was also compared with expected values, matched for sex and age, derived from the second National Health and Nutrition Examination Survey and Continuing Survey of Food Intakes by Individuals 24-hour recall data. The vegan diet was characterized by increased consumption of almonds, cashews, and their nut butters; dried fruits; citrus fruits; soy milk; and greens. We conclude from the present study that a strict vegan diet, which is typically very low in saturated fat and dietary cholesterol and high in fiber, can help children and adults maintain or achieve desirable blood lipid levels.

Adolescent↗
PubMed1990

Intra and inter-person sources of variability in fat intake in a feeding trial of 14 men.

An impediment to analyzing the effect of nutritional factors on biologic processes or health status in human populations arises from the relatively small dietary differences that exist between individuals in relation to large periodic fluctuations in dietary intake and the imprecision with which diet is normally assessed. We report here on characteristics of dietary variability in a group of 14 young men who successfully completed an intervention study specifically designed to create large differences in fat intake between baseline and two dietary intervention-periods each lasting two months (during which safflower and coconut oil supplements were given). We found that in the second supplemental phase of the intervention inter-person sources of variability were greatly increased over the low-fat baseline values. For proportion of calories as fat it increased to 64.2% of total variance from 21.6% without supplementation; for saturated fatty acids, 47.3% from 17.7%; for polyunsaturated fatty acids, 62.4% from 22.8%; and for the P:S ratio, 71.5% from 21.6%. During the first intervention phase we observed only moderate changes. Reasons for the intervention phase differences in effect, implications for feeding trials designed to look at dietary fat effects, and the need for future studies aimed at clarifying these results are discussed.

Adult↗
PubMed1990

Reproducibility and comparability of a computerized, self-administered food frequency questionnaire.

A self-administered dietary assessment questionnaire was developed for the microcomputer to identify individuals whose dietary patterns may put them at risk for cancer. It was tested among 50 adult volunteers in a New York school district. The quantitative food frequency portion of the questionnaire (FFQ), administered twice one month apart, was reproducible for calories, fat, percentage of calories from fat, cholesterol, vitamin A, vitamin C, calcium, and dietary fiber (Spearman r = 0.56-0.87). To test for relative validity, individual nutrient intake calculated from each administration of the FFQ was compared with the nutrient intake calculated from seven-day food records collected one month after the second FFQ administration. Nutrient intake from the first and second FFQ compared with food record nutrient intake yielded a Spearman's correlation coefficient of 0.58 and 0.62, respectively, for percentage of kilocalories from fat. No significant difference in mean intake of percentage of calories from fat was found between the FFQ 1 and FFQ 2 or between the FFQs and the food record. However, there were significant differences between mean food record and FFQ estimates of kilocalories, fat, vitamin A, vitamin C, calcium, and dietary fiber. We concluded that computerized nutrient assessment, which utilizes the subject in data entry, may be suitable for some clinical and educational uses and research studies of intake of fat as a percentage of calories among healthy adults.

Computers↗
PubMed1990

Relationships between food consumption and dietary intake among healthy volunteers and implications for meeting dietary goals.

Quantitative food frequency questionnaires and 5-day food records were used to explore relationships between food consumption and nutrient intake among 65 healthy volunteers who were willing to participate in a dietary fiber intervention study. Spearman's correlation coefficient was calculated between the nutrient intake and the frequency of consumption of each food item, as well as the amount consumed per month. Percentage of calories from fat was related to frequency of consumption and amount of consumption, respectively, of bacon (r = .48, .49), frankfurters and sausage (r = .45, .45), and french fries and fried potatoes (r = .43, .39). Frequency and amount, respectively, of consumption of fruits were most highly correlated with intake of vitamin A (r = .45, .46), vitamin C (r = .44, .48), and dietary fiber (r = .43, .43). We conclude that specific food consumption amounts and/or frequency of eating foods such as legumes, fruits, and whole-grain or bran-rich cereals should be recommended to assist individuals in meeting dietary goals.

Adult↗
PubMed1989

Biochemical epidemiology of colon cancer: effect of types of dietary fiber on fecal mutagens, acid, and neutral sterols in healthy subjects.

Several epidemiological studies suggest an inverse relationship between fiber intake and colon cancer risk. Animal model studies indicate that this inhibitory effect depends on the source of dietary fiber. Because of the potential significance of certain colonic mutagens and secondary bile acids in the pathogenesis of colon cancer, the effect of types of supplemental fiber on fecal mutagens and bile acids was studied in human volunteers. Seventy-two healthy individuals consuming high-fat/moderately low-fiber diets were screened for fecal mutagenic activity using the Ames Salmonella typhimurium/microsomal assay system. Twenty-one of them were found to excrete high levels of mutagens, and 19 of them were recruited for the diet intervention study. All participants provided two 24-h stool specimens and a 4-day food record while consuming their normal (control) diet. They were then asked to consume the control diet plus 10 g of dietary fiber from wheat bran, oat fiber, or cellulose for 5 wk. After each fiber period, they were asked to consume their control diet. At the end of each fiber and control diet period, each subject provided two 24-h stool specimens. Stool samples were analyzed for bile acids and mutagens using the Ames strains TA98 and TA100 with or without S9 (microsomal) activation. The concentrations of fecal secondary bile acids (deoxycholic acid, lithocholic acid, and 12-ketolithocholic acid) and of fecal mutagenic activity in TA98 and TA100 with and without S9 activation were significantly lower during the wheat bran and cellulose supplementation periods. Oat fiber supplementation had no such effect on these fecal constituents. Thus, the increased fiber intake in the form of wheat bran or cellulose may reduce the production and/or excretion of mutagens in the stools and decrease the concentration of fecal secondary bile acids in humans.

Bile Acids and Salts↗
PubMed1988

Effect of low-fat, high-carbohydrate, high-fiber diet on fecal bile acids and neutral sterols.

The effect of a diet low in total fat and high in complex carbohydrates on the excretion of bile acids and neutral sterols and on serum lipids was studied in women, 46-47 years old, who were consuming a mixed Western diet. Participants kept an initial 3-day food record while consuming their normal diet (pre-diet period). During the dietary intervention period (experimental diet) which lasted for 26 days, all volunteers consumed a low-calorie, low-fat (less than 10% of total calories), high-fiber (37 g/day, high-carbohydrate diet. At the 1-year follow-up, the participants completed another 3-day food record, which indicates that these volunteers maintained their caloric and fat intake at levels slightly higher than the experimental diet, but lower than the pre-diet period. Individual 24-hr fecal samples for 2 days and blood samples were collected from the volunteers during each dietary period. Fecal samples were analyzed for neutral sterols and bile acids, and blood samples were analyzed to ascertain cholesterol and triglyceride levels. There were no significant differences in the excretion of neutral sterols between the dietary periods. Fecal secondary bile acids were significantly lower during the experimental and follow-up diet periods compared with the pre-test diet period. Serum cholesterol levels were significantly lower during the experimental and follow-up diet periods than during the pre-test diet period. These results suggest that switching from a high-fat, low-fiber diet to a low-fat, high-fiber diet can reduce the excretion of bile acids which are thought to be involved in the promotion of colon cancer.

Aged↗
PubMed1988

Response to a diet low in total fat in women with postmenopausal breast cancer: a pilot study.

A feasibility study was instituted to determine if women with postmenopausal breast cancer would follow a low-fat diet (20% of kcal) for at least four months. Nineteen women, whose baseline food intake was 1,504 +/- 420 kcal with 56 +/- 16 g of fat, reported a decrease in fat intake to 21 +/- 6 g after two months of dietary intervention. Serum concentrations of cholesterol, HDL cholesterol, and estradiol were significantly reduced by the fifth month on the diet. We conclude that self-selected patients can adhere to a low-fat diet, and that serum cholesterol may serve as an indicator of dietary compliance.

Breast Neoplasms↗
PubMed1987

Metabolic epidemiology of colon cancer: effect of dietary fiber on fecal mutagens and bile acids in healthy subjects.

Because of potential significance of fecal mutagens and secondary bile acids in the pathogenesis of colonic cancer and of inverse association between dietary fiber and colonic cancer risk, the effect of dietary wheat and rye fiber on fecal mutagenic activity and bile acid levels was studied in 15 healthy men and women who were consuming high fat/moderately low fiber diets and excreting high levels of fecal mutagens and bile acids. Each participant provided two 24-h stool specimens and a 3-day diet record while consuming their normal diet (control). All subjects were then asked to consume their normal diet plus 11 g of supplemental fiber per day in the form of whole grain bread for 4 weeks. During the last week of diet intervention, each subject provided two 24-h stool specimens and a 3-day dietary record. Fecal samples collected from both periods were analyzed for bile acids and for mutagens using Salmonella typhimurium strains TA98 and TA100 with and without microsomal activation. The concentration of fecal secondary bile acids was significantly lower during the fiber supplemental period in all subjects. Fiber supplementation also inhibited the fecal mutagenic activity in TA100 and TA98 with and without microsomal activation. Thus, the increased fiber intake in the form of whole wheat and rye bread may reduce the production and/or excretion of fecal mutagens and decrease the concentration of fecal secondary bile acids in humans.

Bile Acids and Salts↗
PubMed1985

Metabolic epidemiology of colon cancer: fecal mutagens in healthy subjects from rural Kuopio and urban Helsinki, Finland.

Fecal mutagenic activity and dietary pattern of rural and urban Finnish population groups with distinct risk for the development of colon cancer were studied in a low-risk population in rural Kuopio and an intermediate-risk population in urban Helsinki. The average daily intake of protein and fat was the same in the two groups but the frequency of consumption of whole-grain cereals and whole-grain bread, as well as the amount of fiber from the bread were higher in Kuopio as compared to Helsinki. Fecal samples collected for 2 days were incubated under anaerobic conditions at 37 degrees C for 96 h, extracted with hexane: peroxide-free diethyl ether, partially purified on a silica Sep-Pak cartridge, and assayed for mutagenic activity using the Salmonella typhimurium/mammalian microsome system. The fecal mutagenic activity was observed with the tester strains TA98 and TA100 with and without microsomal activation in both the population groups. The percentage of samples showing fecal mutagenic ratio greater than 3 with TA98 and TA100 with microsomal activation, was higher in volunteers from Helsinki than in Kuopio.

Adult↗
PubMed1984

Fecal mutagens from subjects consuming a mixed-western diet.

Because of potential significance of fecal mutagens (presumptive carcinogens) in the pathogenesis of colon cancer, feces from 99 healthy subjects from the New York metropolitan area were studied. The diet histories indicate that all participants were consuming a mixed-western diet which is high in total fat and low in fiber. Fecal samples that were incubated under anaerobic conditions at 37 degrees C for 96 h or frozen without incubation, were extracted with hexane: peroxide-free diethyl ether (1:1), partially purified on a silica Sep-pak cartridge and assayed for mutagenicity using the Salmonella typhimurium/mammalian microsome system. Aliquots of fecal samples incubated anaerobically showed a higher frequency of mutagenic activity (per cent samples showing activity) in strains TA98 and TA100 with and without microsomal (S9) activation. In addition, the mutagens requiring S9 activation, were more frequently inactivated when the fecal samples were frozen immediately after defecation and transported to the laboratory. Compared with hexane: ether, extraction of fecal samples with acetone increased the mutagenic activity mostly with TA98 with S9 activation. The HPLC fractionation of hexane: ether extract with methanol: water gradient using reverse phase C-18 column and UV detector at 254 nm indicated that the mutagenic activity (TA98 with S9 activation) is concentrated in several peaks. This is the first demonstration of HPLC profile of fecal samples that are active in TA98 with S9 activation. HPLC profile of fecal extracts and mutagenic activity of these extracts in strains TA98 and TA100 suggest the presence of several types of mutagens in the feces of healthy subjects consuming a high-fat, low-fiber mixed-western diet.

Biotransformation↗
PubMed1983

Metabolic epidemiology of colon cancer: dietary pattern and fecal sterol concentrations of three populations.

The nutrient intake, fecal neutral sterol concentration, and bile acid concentration of populations with a varied risk for colon cancer development were investigated. High-risk populations in the metropolitan New York area and Malmo, Sweden, were compared with an intermediate-risk population in Umea, Sweden. The mean daily intake of protein and fat was comparable in all groups, but the total daily fiber intake was higher in Umea, as was the total daily stool output. There was no difference in the total fiber intake and stool output between Malmo and metropolitan New York. The fecal secondary bile acid concentration was lower in Umea than in the other two areas; no difference was observed between Malmo and metropolitan New York. These results suggest that high fiber intake may be considered protective against colon cancer even in a population with a high risk intake. A high dietary fiber intake may limit colon cancer risk by increasing stool bulk, and thus diluting and/or binding tumor promoters.

Adult↗
PubMed1976

Practices and problems in HANES. Dietary data methodology.

Between April 1971 and June 1974, the first attempt to assess the nutritional status of the non-institutional population of the U.S. was carried out by the DHEW. The survey is known as "HANES" (U.S. Health and Nutrition Examination Survey). Preliminary findings have been released, and further data are expected to be available soon. In this report, dietary collection methods, training and evaluation of interviewers, types of data collected, and data processing procedures of the survey are described, as well as some of the problems encountered.

Adolescent↗