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Biomedical subjects

D A Roe

Publications and source records attributed to D A Roe.

At least 55 records · Page 3Linked to original sources
PubMed1987

Influence of ascorbic acid dose on N-nitrosoproline formation in humans.

A relationship between ascorbic acid intake and N-nitrosoproline (NPRO) excretion in humans on a controlled diet was established. Seven healthy males were placed on a low nitrate, low ascorbic acid diet for 12 consecutive days. On days 3-12, a 5.24 mmol oral dose of sodium nitrate was administered in mid-afternoon, at least 2 h after the subject's last meal. On days 4-12, a 4.35 mmol oral dose of L-proline was administered 30 min after the nitrate dose. Ascorbic acid was given in amounts which increased daily from day 5 to day 10 (0.01-5.68 mmol; 1.76-1000 mg) with the proline. Total 24 h urines were assayed for nitrate, NPRO and total ascorbic acid. Nitrate balance was monitored using [15N]nitrate. Average endogenous nitrate synthesis was 1.28 +/- 0.43 mmol/day/person. NPRO excretion was reduced by 6 nmol/day when 0.05 mmol of ascorbic acid was administered. However, as much as 5.68 mmol ascorbic acid did not return NPRO excretion to levels observed before the nitrate and proline were administered. More than 10 times the ascorbic acid required to completely inhibit NPRO formation in vitro did not return NPRO excretion to baseline levels. These data indicate that endogenous nitrosation may be more facile than predicted by the in vitro chemistry.

Adult↗
PubMed1987

Recollections of nutrition and the chemical environment.

Development of a nutritionist's research interests may be due to the influence of an academic advisor or colleagues, to a personal desire to fill a nutrition information gap or to clinical experience. In the account that is given of one nutritional scientist's research experiences, decision-making on lines of investigation was largely influenced by clinical observation. Goals of the investigator have been to discover why drugs cause nutrient depletion and how drugs influence nutrient requirements. The investigator justifies the need to develop special animal models in order to solve specific problems related to drug-nutrient interactions and to link biochemical changes produced by drugs to pathology.

Animals↗
PubMed1987

Continuance of elderly on home-delivered meals programs.

Data from 2,002 elderly receiving home-delivered meals in 23 counties of New York State in 1984-85 were analyzed using a baseline survey and a six-month follow-up survey. Survival analysis estimated that 37.4 per cent of the clients left the program by the follow-up. The initial drop-out rate was estimated to be 14.2 per cent per month; by six months the rate fell to 3.3 per cent. Whites left the program at a rate 2.6 times (95% CI = 1.9, 3.8) that of minorities. Recent discharge from hospital was associated with the highest relative probability of program discontinuance (2.7, 95% CI = 2.2, 3.4), followed by having cancer (2.1, 95% CI = 1.6, 2.8), and having a non-hip fracture (2.0, 95% CI = 1.3, 2.9). Many of those with cancer died, while those recently discharged and those with non-hip fractures were more likely to leave the program because they were again able to cook for themselves.

Aged↗
PubMed1987

Photodegradation of carotenoids in human subjects.

Photodegradation of vitamins in vitro is responsible for large losses of these nutrients in foods, beverages, and semisynthetic liquid formula diets. In vivo photodegradation of vitamins has been reported for riboflavin in jaundiced infants exposed to blue light and for folate in patients with chronic psoriasis given photochemotherapy. Two recent studies of normal subjects have also shown that photodegradation of carotenoids in plasma occurs with cumulative exposure of the skin to an artificial light source having maximal spectral emission in the UVA range. Females showed a larger effect of the UV light on their plasma carotenoid levels than males. These observations have identified a need for further investigation of the role of sunlight exposure as a determinant of plasma carotenoid levels and vitamin A status in human subjects.

Adult↗
PubMed1987

Relationship between ascorbic acid dose and N-nitrosoproline excretion in humans on controlled diets.

A logarithmic dose-response relationship between ascorbic acid dose and N-nitrosoproline (NPRO) excretion in humans on a controlled diet was established. Seven healthy males were placed on a low-nitrate, low-ascorbic acid diet for 12 consecutive days and given nitrate on days 3-12 and L-proline on days 4-12, after the nitrate dose. Ascorbic acid was given in increasing amounts with the proline on days 5-10. Urine was analysed quantitatively for nitrate, NPRO and ascorbic acid. Ascorbic acid doses as low as 0.05 mmol reduced NPRO excretion by an average of 6 nmol/day; however, as much as 5.68 mmol ascorbic acid did not return NPRO excretion to levels observed before nitrate and proline were administered. Complete inhibition of endogenous NPRO formation from exogenous precursors requires more than the 2:1 molar ratio of ascorbic acid to nitrite that has been demonstrated in vitro. These data may be useful in interpreting epidemiological studies of nitrate exposure and in making dietary recommendations.

Adult↗
PubMed1986

Increase in hepatic gamma-glutamyltransferase (GGT) activity following chronic ethanol intake in combination with a high fat diet.

Increased hepatic gamma-glutamyltransferase (GGT) activity following chronic ethanol consumption has been attributed to enzyme induction, dietary carbohydrate imbalance, and/or to hepatic cell damage. In this study, hepatic GGT activity was increased in rats consuming ethanol (35% of kcals) in a high fat (35% of kcals) diet compared to pair fed and ad lib. fed high fat controls (P less than or equal to 0.01), but no enhancement of activity was observed in those rats consuming ethanol on low fat (11% of kcals) diets. The high-fat-ethanol group also had increased hepatic lipid (P less than or equal to 0.01) and decreased glutathione levels (P less than or equal to 0.05) compared to their ad lib. fed control group. In rats that had ethanol removed from their diet for the final 4 weeks of the 12-week dietary treatment period, levels of GGT, lipid or glutathione were not different from control values. Histochemical evaluation of hepatic GGT activity showed increases associated with centrolobular lipid accumulation in ethanol-fed rats consuming a high fat diet. The cause of the increase in hepatic GGT activity could not be determined from this experiment. However, increased microsomal enzyme activity did not appear to be related to GGT activity. It is suggested that cellular damage following increased lipid accumulation, depletion of hepatic glutathione, or changes in biliary flow may be associated with the increased GGT activity.

Alcoholism↗
PubMed1986

History of promotion of vegetable cereal diets.

Vegetarian regimes have been advocated since the eighteenth century by men and women in search of physical and spiritual health. Vegetarian theorists who professed to follow the tenets of the ancient philosopher Pythagoras believed that the diet should be part of an ascetic lifestyle. Others who promoted vegetarianism did so to symbolize their commitment to health and social reform. In the 1830s vegetarians in the United States, particularly Sylvester Graham and his followers, preached that special foods, mainly coarse whole meal breads, had particular virtues and were indeed the earliest health foods. Nutritional ideas and products that are the outcomes of the early vegetarian movement include a commitment to high fiber diets, the popularity of breakfast cereals, and the graham cracker.

Diet↗
PubMed1986

Combined effects of exercise and restriction of energy intake on moderately obese women.

The current study was designed to assess the contribution of dietary-induced weight reduction on improvements in functional capacity in moderate obesity. Twelve females (means age = 29 yr, means fat percentage = 37%) served as subjects for the study. Subjects trained on a cycle ergometer 30 min.day-1, six day.wk-1 for three or six weeks at 75 to 85 per cent of maximum heart rate (HR max). Improvements in maximal oxygen uptake (delta VO2 max I.min-1) and functional capacity (delta VO2 max ml.kg-1 min-1) were compared in an attempt to separate out training and dietary effects respectively. Measurements were also taken on both the cycle ergometer and treadmill to test for any specificity of training effects. Changes in body composition were assessed by densitometry. Following three weeks of training, there was an average increase in VO2 max ml.kg-1 min-1 on the cycle ergometer and the treadmill of 14 and 19 per cent respectively. By six weeks, this had increased to 18 and 26 per cent respectively. The contribution of weight reduction to the improvements in functional capacity was calculated to range from 20 to 33 per cent. Thus, both energy restriction and exercise training appear to be effective means of improving functional capacity in moderately obese women.

Adult↗
PubMed1986

Drug-nutrient interactions in the elderly.

Drug metabolism and efficacy may be affected simply by changing the diet of an elderly patient. For example, an increase in the protein content of the diet can affect the bioavailability of certain drugs and increase the rate of drug metabolism. All elderly patients receiving long-term drug therapies that cause diarrhea, with or without steatorrhea, should be monitored for evidence of hypokalemia, folate deficiency, and deficiencies of vitamins A and D.

Absorption↗
PubMed1985

Effects of exercise on riboflavin requirements: biological validation in weight reducing women.

The present study was designed to evaluate our previous estimates for riboflavin requirement, 0.96 mg/1000 kcal during nonexercise and 1.16 mg/1000 kcal during exercise in overweight women. Two groups of 6 weight reducing women consumed either 1.16 mg riboflavin/1000 kcal (HR) or 0.96 mg/1000 kcal (MR). The study was two, 3 period by 2 treatment (exercise or nonexercise) crossover designs, one design at each level of riboflavin. Erythrocyte glutathione reductase activity coefficients (AC) significantly increased in both groups from 1.16 +/- .02 to 1.20 +/- .03 in group HR and from 1.31 +/- .04 to 1.36 +/- .02 in the MR group during nonexercise and exercise, respectively. ACs increased in the HR group due to an increase in total enzyme activity while ACs increased in the MR group due to a decrease in basal enzyme activity reflecting decreased flavin availability. There were no differences in aerobic capacity, weight loss, nor change in lean body mass between the two groups. Thus, 0.96 mg/1000 kcal was not adequate during either nonexercise or exercise periods while the 1.16 mg/1000 kcal was adequate.

Adult↗
PubMed1985

Therapeutic effects of drug-nutrient interactions in the elderly.

The elderly are the major drug users both because they need specific prescription drugs for control of chronic diseases and because they make excessive use of over-the-counter (OTC) drugs. Therapeutic drugs that are required may be discontinued because the individuals suffer side effects or because the drug is ineffective. Adverse drug reactions in the elderly may result from drug overuse or misuse, slowed drug metabolism or elimination secondary to aging or to age-related chronic disease, intake of alcohol, food-drug incompatibilities, or nutrient-drug interactions. The timing of drug intake in relation to food intake is an important determinant of therapeutic efficacy in the elderly. Food-drug interactions in the gastrointestinal tract may reduce drug absorption. Enteral formula feeding may also interfere with drug absorption. Conversely, absorption of certain drugs (e.g., thiazides) may be promoted by meal-induced slowing of gastric emptying time. Therapeutic diet prescription can influence drug responses in the elderly because the protein composition of the diet influences the rate of drug metabolism. Nutrient depletion secondary to the effect of drugs may be recognized as an important and often avoidable type of adverse drug reaction.

Aged↗
PubMed1985

Development of riboflavin deficiency in alcohol-fed hamsters.

Riboflavin deficiency may be induced by dietary restriction or by drugs. High incidence of rifoflavin deficiency in alcoholics might be due to diet, to the toxic effect of alcohol, or to an interaction of these variables. Aims of this study were to investigate the effects of alcohol on the riboflavin status of Syrian hamsters fed three different levels of riboflavin in a liquid diet. Male Syrian outbred hamsters of 5 weeks of age, acclimated to liquid diets, were randomly assigned to groups that received alcohol-containing diets (AR0, AR1, AR2) or nonalcohol-containing diets (OR0, OR1, OR2) where R1 = 0.5 microgram riboflavin/kcal added and R2 = 1.5 microgram riboflavin added/kcal. No alcohol groups were pair-fed to the alcohol groups. Riboflavin status was monitored by repeated erythrocyte glutathione reductase assays. Animals were sacrificed at 13 weeks of age and liver flavins were determined. Riboflavin depletion occurred during the first 2 weeks of the study and this was followed by a 4-week period of relative improvementin riboflavin status. Thereafter riboflavin depletion continued in all groups but most severely in the alcohol group as measured by erythrocyte glutathione reductase assays. Total liver flavins were lowest in the alcohol-fed, riboflavin-restricted group, indicating that chronic alcohol feeding can induce riboflavin deficiency when intake of the vitamin is marginal.

Aging↗