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Biomedical subjects

J W Erdman

Publications and source records attributed to J W Erdman.

At least 55 records · Page 3Linked to original sources
PubMed1995

Phytic acid in health and disease.

Phytic acid (PA), a major phosphorus storage compound of most seeds and cereal grains, contributes about 1 to 7% of their dry weight. It may account for more than 70% of the total kernel phosphorus. PA has the strong ability to chelate multivalent metal ions, especially zinc, calcium, and iron. The binding can result in very insoluble salts that are poorly absorbed from the gastrointestinal tract, which results in poor bioavailability (BV) of minerals. Alternatively, the ability of PA to chelate minerals has been reported to have some protective effects, such as decreasing iron-mediated colon cancer risk and lowering serum cholesterol and triglycerides in experimental animals. Data from human studies are still lacking. PA is also considered to be a natural antioxidant and is suggested to have potential functions of reducing lipid peroxidation and as a preservative in foods. Finally, certain inositol phosphates, which may be derived from PA, have been noted to have a function in second messenger transduction systems. The potential nutritional significance of PA is discussed in this review.

Animals↗
PubMed1995

Patients with anorexia nervosa demonstrate deficiencies of selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of plasma lipids.

The objective of this study was to assess the essential fatty acid status of patients with anorexia nervosa. Blood was collected from eight fasting female anorexia nervosa patients with a mean of 81% ideal body weight. Fatty acid composition of phospholipids, nonesterified fatty acids, triglycerides and cholesteryl esters of plasma were determined by capillary gas chromatography to indicate polyunsaturated fatty acids status compared with 19 healthy female adults < 25 y old. Subjects with anorexia nervosa showed polyunsaturated fatty acid deficiencies in plasma phospholipids different from simple nutritional essential fatty acid deficiency or chronic malnutrition. The phospholipid profile showed significantly lower (n-6) and (n-3) elongation and desaturation products, and elevated short-chain saturated, short-chain monounsaturated, branched-chain and odd-chain fatty acids. These elevations indicate enhancement of biosynthesis of alternative fatty acids that only partially compensated for the loss of polyunsaturated fatty acids in providing membrane "fluidity." Calculated mean melting point of the fatty acids of phospholipids in patients with anorexia nervosa was elevated 7.7 degrees C above normal values. These results demonstrate that patients with anorexia nervosa have deficiencies of selected essential fatty acids, compensatory changes in nonessential fatty acids and decreased fluidity of plasma lipids.

Adolescent↗
PubMed1995

Comparative absorption and transport of five common carotenoids in preruminant calves.

Preruminant calves, maintained in a monogastric state by feeding an all-liquid diet, were used to compare the serum appearance and lipoprotein transport of five different carotenoids over 144 h. Thirty newborn calves were fed milk replacer for 1 wk and then randomly assigned to six groups (n = 5), with each group receiving a single 20-mg oral dose of beta-carotene in water-soluble beadlets, canthaxanthin in water-soluble beadlets, lutein in oil, lycopene in oil, crystalline alpha-carotene in oil or crystalline beta-carotene in oil as part of a morning meal. Serial blood samples were taken by jugular puncture for up to 1 wk post-dosing. Lipoprotein separation and analysis were completed with selected animals. All carotenoids were absorbed, but in variable amounts. At peak serum carotenoids levels, HDL contained 70-90% of the carotenoids. Canthaxanthin and lutein peaked earlier in serum (8 and 12 h) than did the less polar lycopene, alpha-carotene, and beta-carotene (16, 24 and 24 h). Canthaxanthin and lutein were also cleared more quickly from the serum. Serum concentrations of alpha-carotene and lycopene displayed slower disappearance rates than did beta-carotene. The peak serum level (nmol/L +/- SEM) of canthaxanthin (392 +/- 136) was lower than that of beta-carotene (1245 +/- 425), and carotenoids levels of calves receiving these commercial beadlet sources were higher than the serum levels of calves receiving beta-carotene (45 +/- 17.5), alpha-carotene (42 +/- 18.0), lutein (51 +/- 9.5) and lycopene (18 +/- 4.6), which were fed in oil.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1995

Contributions of exercise, body composition, and age to bone mineral density in premenopausal women.

The purpose of this cross-sectional study were to determine whether exercisers have greater bone mineral density (BMD) than nonexercisers, whether aerobic dancers have greater BMD than walkers, and to determine the contributions of energy expenditure, body composition, and dietary factors to spine and femur BMD. Measurements were obtained on 93 eumenorrheic women (walkers N = 28; aerobic dancers, N = 34; nonexercisers, N = 31) ages 25-41 yr; lumbar spine and proximal femur BMD, body composition, physical activity, and nutrient intakes. Mean height, weight, and body mass index and median age and calcium intakes were similar for the three groups. Mean (+/- SD) values of the spine, total femur, and femoral neck BMD, respectively, were: walkers (1.092 (+/- 0.098), 0.947 g.cm-2), dancers (1.070 (+/- 0.124), 0.990 (+/- 0.104), 0.908 (+/- 0.106) g.cm-2), and nonexercisers (1.020 (+/- 0.112), 0.887 (+/- 0.073), 0.792 (+/- 0.089) g.cm-2) multiple regression analyses indicated that exercise contributed to spine (P = 0.018), total femur (P =0.012), and femoral neck (P < 0.0001) BMD, whereas type of exercise (aerobic dance vs walking) did not (P > 0.05). Total femoral BMD was influenced by exercise (P = 0.012) and energy expenditure (P = 0.023), while vertebral BMD was influenced by age (P = 0.0067), body weight (P = 0.017), and exercise (P = 0.018). These findings suggest that walking and aerobic dance exercise may provide physically active premenopausal women with greater lumbar and femoral BMD than sedentary females.

Adult↗
PubMed1994

Pharmacokinetics of beta-carotene and canthaxanthin after ingestion of individual and combined doses by human subjects.

OBJECTIVE: This study investigated effects of ingestion of a combined dose of beta-carotene and canthaxanthin on their individual pharmacokinetics in serum. METHODS: During three 5-day study periods, two subjects ingested either a 25 mg dose of beta-carotene, a 25 mg dose of canthaxanthin, or a combined dose of 25 mg each of beta-carotene and canthaxanthin. Pharmacokinetics of the individual and combined doses were compared within subjects. RESULTS: Ingestion of a concurrent beta-carotene dose reduced the peak serum canthaxanthin concentration by 38.8 +/- 6.5%, and the 24- and 72-hour areas under the serum canthaxanthin concentration-time curves by 38.1 +/- 6.4 and 34.4 +/- 7.4%, respectively. The suggested antagonism between beta-carotene and canthaxanthin was not reciprocal; beta-carotene inhibited the appearance of canthaxanthin in serum but canthaxanthin did not inhibit the appearance of beta-carotene. CONCLUSION: Our data suggest that ingestion of a combined pharmacologic dose of beta-carotene and canthaxanthin reduces the bioavailability of the canthaxanthin dose.

Administration, Oral↗
PubMed1994

Intake of 25 g of soybean protein with or without soybean fiber alters plasma lipids in men with elevated cholesterol concentrations.

Twenty-one mildly hypercholesterolemic men consumed a diet that was low in fat (< 30% of energy) and cholesterol (300 mg/d) and were given muffins containing 25 g protein + 20 g dietary fiber daily from either isolated soybean protein + soybean cotyledon fiber, isolated soybean protein + cellulose, casein + soybean cotyledon fiber or casein + cellulose. All subjects progressed through the low fat, low cholesterol baseline period, lasting 2 wk, and then through all four dietary treatments, lasting 4 wk each, according to a Latin square design. Plasma concentrations of total, LDL, HDL and VLDL cholesterol, total and VLDL triacylglycerols, and apolipoprotein A-I and B were measured at the end of each period. When data from all subjects were analyzed, dietary treatments did not influence lipemia; however, in subjects with initial total cholesterol concentrations > 5.7 mmol/L, both isolated soybean protein treatments resulted in significantly lower total cholesterol compared with the two casein treatments (P < 0.05). In addition, a negative linear relationship was observed when a subject's total or LDL cholesterol change after each of the soybean treatments was regressed against the subject's baseline cholesterol concentration (P < 0.05). Apolipoprotein A-I varied dependent on baseline cholesterol with no apparent pattern, whereas apolipoprotein B levels were not affected. Results indicate that consumption of 25 g soybean protein/d is associated with lower total cholesterol concentrations in individuals with initial cholesterol concentrations > 5.7 mmol/L.

Adult↗
PubMed1994

Mongolian gerbils (Meriones unguiculatus) absorb beta-carotene intact from a test meal.

Because a yellow color has been observed in the fat pads of Mongolian gerbils fed a nonpurified diet, we designed the current study to determine whether adult male gerbils would absorb beta-carotene intact from a test meal. Thirty-five gerbils (80-90 g) were adapted to the laboratory and fed a standard purified diet free of beta-carotene for 16-19 d. Gerbils were then fed a test meal consisting of 279 nmol of beta-carotene as 10% water-soluble beadlets suspended in 0.5 mL of Ensure. Gerbils (n = 5) were killed at 0, 2, 4, 6, 12, 24 or 72 h after the test meal, blood was obtained by cardiac puncture, and tissues were taken for beta-carotene analysis. No beta-carotene was detected in serum at 0 or 72 h, whereas beta-carotene was present at all other sampling times. Serum beta-carotene peaked at 4 h, at a level of 88 nmol/L. beta-Carotene was detected in the liver of all groups; however, the concentration increased from -34 pmol/g to a maximum concentration of 926 pmol/g at 24 h after the test meal. Other tissues also contained beta-carotene. The results demonstrate that Mongolian gerbils, like ferrets and preruminant calves, absorb beta-carotene intact when beta-carotene is provided at a physiological level in a test meal. This species may be particularly useful for evaluation of the role of antioxidants, such as beta-carotene, in LDL oxidation.

Administration, Oral↗
PubMed1993

Vitamin A status of alcoholics upon admission and after two weeks of hospitalization.

The purpose of this study was to determine the vitamin A status of alcoholics upon admission and after a brief in-patient stay. Fasting blood was drawn from 28 randomly selected subjects who were presumed to represent a wide range of liver disease severity. Admission laboratory tests revealed hypozincemia in 14.8% of subjects, while serum retinol and retinol-binding protein (RBP) were depressed below normal range in 15 (57.1%) and 7 (25%) of the subjects, respectively. Significant linear correlations were found between serum retinol and RBP (r = 0.90, p < or = 0.0001), serum retinol and albumin (r = 0.76, p < or = 0.0001), serum retinol and serum zinc (r = 0.56, p < or = 0.0003), and serum retinol and serum triglycerides (r = 0.42, p < or = 0.006). All subjects with elevated serum bilirubin levels demonstrated depressed serum retinol levels. However, elevated molar ratios of retinol to RBP suggest that the carrying capacity of RBP was at times exceeded, even with low serum retinol levels. Follow-up of 12 subject after 2 weeks of hospitalization revealed significant individual changes in blood chemistry, but no general trends. Although this study emphasizes the need for individual evaluation and treatment, elevated bilirubin levels may be indicative of low serum retinol levels in the alcoholic. Caution in levels of vitamin A therapy in these cases is advised, and consideration should instead be given to beta-carotene supplementation.

Alcoholism↗
PubMed1993

The ferret as a model for evaluation of the bioavailabilities of all-trans-beta-carotene and its isomers.

The objective was to develop the ferret as a model for evaluation of the bioavailabilities of natural and synthetic beta-carotenes in foods. For these studies, a low carotenoid purified diet was formulated that produced excellent food intake and adequate growth. After consuming the diet for 16 d, ferrets were randomly assigned to one of three groups. For a 10-d period, they ingested a standardized amount of all-trans-beta-carotene (18 mumol/L) from either carrot juice, a test beverage of beta-carotene beadlets dispersed in fruit juices, or a control beverage of beta-carotene beadlets dispersed in water. Accumulations of all-trans-beta-carotene in the sera, livers and adrenals of ferrets that consumed the carrot juice were significantly lower (P < 0.02) compared with those of ferrets that consumed the test or control beverages. The content of a cis-isomer component relative to that of all-trans-beta-carotene was higher in each beta-carotene beadlet-fortified beverage than in the liver and adrenal tissues of ferrets that ingested the beverage; the cis-isomer was not measurable in sera. The content of all-trans-beta-carotene relative to that of all-trans-alpha-carotene, a structural isomer, was higher in carrot juice than in sera of ferrets that ingested the juice. We conclude that: 1) all-trans-beta-carotene is less bioavailable from carrot juice than from beta-carotene beadlet-fortified beverages, and 2) there are apparent bioavailability differences between isomers of beta-carotene in ferrets.

Animals↗
PubMed1993

The accumulation of alpha- and beta-carotene in serum and tissues of preruminant calves fed raw and steamed carrot slurries.

The preruminant calf model was used to evaluate the effects of mild heat treatment on the serum and tissue accumulation of alpha- and beta-carotene from carrots. Twenty-four 1-wk-old Holstein male calves were assigned to one of four groups and fed a milk replacer diet. Negative control animals received no additional supplement. The three remaining groups received an additional 20 mg beta-carotene/d from either water-soluble beadlets, homogenized raw carrots or homogenized steamed carrots. Serum samples were obtained daily, and calves were killed after 7 d and samples of serum, liver and adrenal collected. Tissue and serum alpha- and beta-carotene concentrations were not significantly higher in steamed carrot-fed animals than in raw carrot-fed animals. The molar ratios of beta-carotene to alpha-carotene in both raw carrot-fed and steamed carrot-fed groups were highest in adrenal tissues, intermediate in serum and lowest in the diets. None of these differences were statistically significant. When the serum, liver and adrenal beta-carotene data were pooled, the mean relative accumulation of beta-carotene, expressed as a percentage of the mean response of calves receiving water-soluble beadlets, was 46.8% for calves fed raw carrots and 74.0% for calves fed steamed carrots. These results suggest a small enhancing effect of mild heat treatment of carrots on the serum and tissue accumulation of carotenoids.

Animals↗
PubMed1993

Bone zinc is poorly released in young, growing rats fed marginally zinc-restricted diet.

The effect of marginal zinc restriction on bone zinc release was studied. Male weanling rats were fed zinc-adequate diet (12 mg zinc/kg diet) for 1 wk, intubated with 65Zn, refed the zinc-adequate diet for an additional week, and divided into one baseline group and five marginally zinc-restricted groups (6 mg/kg) and five corresponding zinc-adequate pair-fed groups. Significantly lower (P < 0.05) 65Zn radioactivity (10-20%) in the first week was observed in femurs of rats fed the marginally zinc-restricted diet without further change in the following weeks. Pair-fed rats showed higher 65Zn radioactivity in femurs in the second week, and the level was maintained. Similar results were found in tibia 65Zn radioactivity. Muscle zinc concentration was higher in the first week (P < 0.05) but subsequently returned to baseline levels in the second week through the fifth week. The results support the existence of two zinc pools in the skeleton, one a small, rapidly turning-over pool (10-20% in size), and the other a slowly turning-over pool. When rats suffer marginal zinc restriction, zinc from the readily turning-over bone pool is utilized for soft tissue needs, followed by decreased growth rate to maintain zinc homeostasis.

Animals↗
PubMed1993

Interactions of oral beta-carotene and canthaxanthin in ferrets.

Interactive effects of an oral dose of equal quantities of beta-carotene and either canthaxanthin or lycopene on serum and tissue beta-carotene accumulations were investigated in domestic ferrets. Like humans, ferrets absorb a substantial portion of ingested beta-carotene intact and accumulate it in tissues. After the ferrets ingested a low carotenoid purified diet for 13 d, they were randomly assigned to one of two groups of six animals. One group was dosed with beta-carotene (10 mg/kg body weight) and the other with beta-carotene and either canthaxanthin (Experiment 1) or lycopene (Experiment 2) (10 mg/kg body weight for each). In Experiment 1, ferrets that received a combined dose of beta-carotene and canthaxanthin had serum beta-carotene concentrations that were significantly lower at 8, 12 and 24 h post-dosing (P < 0.05), compared with those that received an individual dose of beta-carotene; liver, adrenal and kidney beta-carotene concentrations were also significantly reduced. In Experiment 2, ferrets that received a combined dose of lycopene and beta-carotene had lower serum and tissue beta-carotene concentrations than in those that received beta-carotene alone; the differences were not statistically significant with the exception of serum beta-carotene concentrations at 24 h post-dosing. The results suggest that, at the doses given, a concurrent oral canthaxanthin dose has a specific antagonistic effect on the bioavailability of a beta-carotene dose in ferrets.

Administration, Oral↗
PubMed1993

Effects of acute ethanol doses or dietary phenobarbitol with carbon tetrachloride exposure on vitamin A status of rats.

Hepatotoxins such as ethanol and CCl4 are known to adversely affect vitamin A metabolism, although the effects of acute exposure to these agents have received less evaluation. The purpose of this study was to determine the effects of vitamin A status after a series of acute ethanol doses or a series of CCl4 inhalation challenges with concurrent phenobarbital exposure in the diet of rats. The depressed hepatic vitamin A seen after one ethanol dose was not sustained after repeated dosings. However, the significantly increased urine and liver radiolabeled vitamin A recovery after three acute ethanol exposure periods suggests adaptive physiologic and metabolic changes after the initial dose. The results of repeated CCl4/phenobarbital dosings on vitamin A status paralleled, for the most part, the ethanol results. Thus, the initial acute exposure of hepatotoxic agents causes metabolic changes that are not fully sustained as the animal adapts to these challenges.

Alcoholic Intoxication↗