Call number: LD2668 .T4 1978 K58 / Master of Science

The ability of wheat bran and oat hulls to bind copper and zinc using a new chromatographic technique was investigated and compared to a centrifugation method. Also investigated was the bioavailability of copper which had been exogenously bound to wheat bran then fed to mice and rats. Wheat bran bound 6 mg Cu/g fiber when pH was raised to 7. Less binding occurred at lower pHs. Seven mg of zinc bound to wheat bran at pH 5 while only a trace bound at pH less than 2. Oat hulls bound 3 mg Cu/g fiber at pH 5, and less than 1 mg of zinc bound per g of oat hull at pH 6. Binding for both fibers depended on the level of mineral added to the fiber slurry during incubation. But only wheat bran binding capacity was influenced by pH. The two methods used did not compare favorably, in all cases, to the amount of mineral bound to fiber. Copper when bound to wheat bran, was utilized in both species, with differences occurring between species was noted. Rats fed the copper bound diet compared favorably with rats fed the copper-adequate diet as determined by body weight, weight gain, heart weight, liver copper concentration and heart copper concentration. Mice, on the other hand showed similar liver and heart concentrations of copper for mice fed either the copper-bound diet or the copper-adequate diets. The in vitro results showed that binding of copper or zinc to wheat bran occurred at a pH similar to the intestinal pH and wheat bran binds more copper and zinc than oat hulls. Oat hulls may prove to be a better dietary fiber source for those people who need to increase their dietary fiber, because oat hulls do not appear to bind copper or zinc and would not likely impair their absorption. Although wheat bran had a high binding capacity for copper, this binding did not significantly inhibit copper absorption as determined in animal studies suggesting that fiber-mineral binding (at least for copper bound to wheat bran) does not cause mineral deficiency symptoms as claimed by many researchers.

The present study was designed to investigate the effects of exercise on vitamin B-6 metabolism. Four groups of subjects (intermittent, college, untrained, and high school) consisting of nineteen male and two female individuals, participated in the study. The subjects exercised either on a bicycle ergometer, by running three 1500 meter intervals, or both. Blood samples drawn prior to exercise (pre), after exercise (post), and 30 minutes after exercise (30 minute post), were analyzed for plasma pyridoxal 5'-phosphate (PLP), plasma B-6 (PB6), glucose, hemoglobin and hematocrit. A 24-hr urine collection the day before and the day of exercise was analyzed for urinary B-6 (UB6), 4-pyridoxic acid (4PA), creatinine, and urea nitrogen. The dietary intake of the four groups was greater than the RDA in vitamin B-6, riboflavin, thiamin, niacin, vitamins A and C, calcium and iron. The B-6/protein ratios of the college and untrained groups were adequate while the high school group's ratios were considered inadequate. The bicycle ergometer had a significant effect on the plasma PLP levels of the college and untrained groups (P< 0.005) and PB6 levels of the college group following exercise (P< 0.005). The 30 minute post plasma PLP levels were significantly lower for the college group (P< 0.005). During the run, the college group had significantly higher post exercise levels of plasma PLP (P< 0.005) and PBS (P< 0.005} as compared to the pre exercise sample. The high school group also had significantly higher levels of plasma PLP following, exercise for all three runs (P< 0.005, P< 0.025, and P< 0.01, respectively) as well as higher PB6 levels (P< 0.025, P< 0.01, and P< 0.025, respectively). The college athletes had a greater percent change in plasma PLP (P < 0.01) from the pre to post sample during the run as compared to the high school athletes. Urinary B-6 and 4PA were not significantly altered during either exercise suggesting a shift in PLP and the unphosphorylated forms of vitamin B-6 from one compartment to another. The significantly higher levels of plasma PLP and PB6 following exercise were attributed to an increased utilization of glycogen phosphorylase in the skeletal muscle with a subsequent release of PLP. / Graduation date: 1982

The effect of pyridoxine (PN) supplementation on the activities of erythrocyte alanine aminotransferase (EAlaAT) and aspartate aminotransferase (EAspAT) was observed in five men, aged 22 to 25 years. The subjects received a constant diet containing 1.34 mg of vitamin B-6 Monday through Friday of each week during this five-week study. Starting on day 6 of week 1, the subjects were given orally 5 mg PN daily, except on Tuesday and Thursday of each week when they were given either no PN or 2 mg of vitamin B-6 in the form of crystalline PN or as food. Basal and pyridoxal phosphate (PLP)-stimulated EAlaAT and EAspAT activities were determined weekly. Both basal and PLPstimulated activities of the two enzymes increased after only three days of PN supplementation and continued to increase throughout the four weeks of PN supplementation; percent stimulation by PLP added in vitro decreased concomitantly. It is suggested that the binding of PLP to erythrocyte apoaminotransferases may be another reservoir for vitamin B-6. / Graduation date: 1982

The effect of pyridoxine (PN) supplementation on lymphocyte responsiveness was investigated in 15 elderly volunteers (aged 65-81 years) by measuring lymphocyte proliferation to T and B cell mitogens, lymphocyte subpopulations with monoclonal antibodies (T3, T4, T8) and plasma pyridoxal 5'-phosphate (PLP) concentration at pre-supplementation and after 1 and 2 months of daily supplementation. Eleven subjects received 50mg of PN-HC1 and 4 received a placebo. Dietary histories were also evaluated for Intake of vitamin B-6, protein and kilocalories. Mitogens used for the stimulation of lvmphocyte proliferation were phytohemagglutinin (PHA), concanavalln A (Con A), pokeweed mitogen (PWM), and Staphylococcus aureus Cowain I (SAC). Plasma PLP was measured by a radio tracer method. Before supplementation, mean PLP of the 15 subjects was 31.7 +/- 14.1 nM; 5 PN and 3 placebo treated subjects had low PLP levels. After 1 and 2 months of PN-HCl supplementation, the PLP levels Increased by 195 +/-88 nM and 201 +/-84 nM, respectively. Lymphocyte proliferation In response to PHA, PWM, and SAC Increased significantly (p < 0.05) with PN supplementation. Among PN-treated subjects, Ivmpbocyte blaatogenesls was significantly greater In response to Con A and PWM in individuals whose initial PLP was low. Percentages of T3+ and T4+, but not T8+ cells increased significantly In PN-treated individuals. These results suggest that vitamin B-6 status is important in maintaining immunocompetence in the elderly. / Graduation date: 1986

The study was designed to indirectly understand muscle glycogen utilization during prolonged exercise when either glucose, fructose, or water is ingested. Eight trained adult males exercised on a cycle ergometer at 58±7% of V02 max for 2 h on 2-4 occasions. At 0 minutes of exercise and at 30-minute intervals throughout the exercise, the subjects ingested 200mL of fluid containing either glucose, fructose, or plain water in a double-blind, randomized fashion. The carbohydrate (CHO) fluid concentration was based on each subject's body weight (BW): Ig CHO X kg⁻¹ BW X L⁻¹ water and ranged from 5.8-9.2% (average=7.5%) of BW. Blood samples were collected from subjects at rest and immediately prior to fluid ingestion during exercise and analyzed for hematocrit, hemoglobin, and plasma levels of glucose, lactate, and pyridoxal 5'-phosphate (PLP). ANOVA showed no significant difference among treatments at any time of exercise for mean plasma lactate and PLP levels (p > 0.05). Although not significant, mean plasma lactate and PLP concentrations tended to be lower when glucose was consumed as compared to fructose and water. The mean plasma glucose level, however, uas significantly different among treatments at specific time points of exercise (p < 0.05). During exercise, mean plasma glucose decreased, and there was a higher plasma glucose level when glucose and fructose fluids were ingested as compared to water. At 60 minutes of exercise, this difference uas evident for both glucose and fructose ingestion (p < 0.05). At 90 and 120 minutes of exercise, fructose ingestion produced a significantly higher mean plasma glucose level than either water or glucose ingestion (p < 0.05). It is hypothesized that the higher plasma glucose levels provided a greater blood glucose supply to working muscles, thereby sparing muscle glycogen stores. The findings indicate that for the long-term exerciser, consumption of a 5.8-9.2% fructose solution may promote less muscle glycogen utilization than either glucose or water, thereby possibly increasing endurance. / Graduation date: 1986

The purpose of the study was to set up an in vitro model of the colon which would permit the analysis of cellulose fermentation by human colonic microflora. Studies of the degradation of polysaccharides by colonic bacteria may help to explain the observed physiological consequences of consuming dietary fiber common in foods. This study resulted in the use of a simple anaerobic batch fermentation system. It is assumed that the bacteria in fresh feces are representative of colonic bacteria. This batch culture system consists of the culture medium, the food fiber and the fecal inoculum. The fecal inoculum is prepared from freshly voided feces from a single individual. The food fiber is prepared from the vegetable/fruit starting material by repeated extraction with 90% ethanol, resulting in an alcohol insoluble residue(AIR). Extents of cellulose fermentation were measured after 4, 8, 12 and 24 hour fermentation periods at 37°C. The cellulose content of the samples before and after fermentation was determined by measuring the glucose yield (glucose oxidase assay) from an acid hydrolysate of the residue remaining after repeated acid detergent extractions. The extent of cellulose fermentation was then estimated by difference. The susceptibility to intestinal fermentation of the cellulose component of acorn squash and red beets was investigated using this model system. The cellulose content of squash and beet AIR was 26.71% ± 0.95% and 23.22% ± 0.89%, respectively. The extent of cellulose of fermentation of squash cellulose after 4, 8, 12 and 24 hrs incubation was 6.04% ± 0.69%, 10.58% ± 2.10%, 17.11% ± 6.37% and 96.18% ± 1.36%, respectively. The extent of fermentation of beet cellulose after 4, 8, 12 and 24 hrs incubation was 17.52% ± 1.83%, 23.52% ± 1.44%, 30.53% ± 4.12% and 96.06% ± 0.39%, respectively. The results indicate that the cellulose component of both vegetables is susceptible to considerable degradation within the human intestinal tract. / Graduation date: 1991

The objectives of this study were a) to determine if pyridoxine (PN) supplementation increases the rate at which plasma urea and ammonia return to basal levels, following exercise, b) to determine, by open circuit calorimetry, the utilization of carbohydrates, and c) to further understand vitamin B-6 metabolism during and following strenuous exercise. Six male athletes (age 26 ± 5 years and VO₂ max 66.4 ± 6.9 ml/kg/min) exercised for 1 hour on a cycle ergometer at 72% VO₂ max at two points during a 17 day study. For the first 8 days subjects received daily a placebo solution, while during the next half they received a PN dose (20 mg). Subjects consumed a constant diet the day before, day of, and day after the exercise test. Blood samples were taken the day of the exercise test at fasting (Fl), pre-exercise (PE), during exercise (DE), 1 min post exercise (I'P), 6 hour post exercise (6hP), and the day after the exercise test at fasting (F2). Plasma was analyzed for ammonia, urea, and pyridoxal 5'-phosphate (PLP). ANOVA showed no significant difference between treatments for either plasma ammonia or urea. While there was a significant increase (p<0.001) in plasma ammonia levels over time with the placebo, with supplementation the increase over time was not significant. With PN supplementation, plasma PLP levels were significantly correlated (p<0.05) with plasma ammonia levels at I'P. A slight decrease in plasma urea concentration was observed with the PN treatment at PE, DE, I'P, and 6hP. It was concluded that PN may reduce adverse consequences of plasma ammonia and urea seen with exercise. On the other hand, pyridoxine supplementation may produced a shift in the utilization of substrates of the subjects. Metabolic rate results showed that the contribution of carbohydrates as a energy source increased from 43.5 ± 13.7% with the placebo, to 52.0 ± 6.7% with the PN treatment (not significantly different). This observation lead to the conclusion that PN supplementation decreases glycogen stores compared to the glycogen stores without supplementation. Since the findings from this study suggest slightly more rapid plasma ammonia and urea restoration but decreased glycogen stores, they do not provide evidence for or against an increased need for vitamin B-6 in persons that are involved in strenuous exercises of medium duration. / Graduation date: 1988

Four studies were conducted to evaluate the effect of varying levels of vitamin B-6 (B6), protein and pyridoxine glucoside (PNG) on B6 status and requirements of women. In the first two studies, women were fed a constant protein diet and vitamin B-6 intakes of 0.84 to 2.39 mg/d during 10- to 15-day experimental periods. Significant differences among intake levels were found in urinary 4-pyridoxic acid (4PA) and total vitamin B-6 (UB6), plasma pyridoxal 5'-phosphate (PLP) and total vitamin B-6 (TB6), and urinary xanthurenic acid (XA) following a tryptophan load. Significant correlations were found between B6 intake and 4PA, UB6, plasma PLP, TB6, erythrocyte alanine aminotransferase (EALT) percent stimulation, and postload urinary XA and volatile amines (VA, kynurenine plus acetylkynurenine). More than 1.33 mg B6/d (> 0.016 mg B6/g dietary protein) was required for adequate B6 status. In a third study, nine women were fed diets providing 1.25 mg B6/d and three levels of protein (0.5, 1.0 and 2.0 g/kg body weight), for 14 days each. Significant differences in urinary 4PA, plasma PLP, and postload urinary VA were found among protein levels. Nitrogen intake was significantly negatively correlated with urinary 4PA and plasma PLP, and positively correlated with EALT percent stimulation and postload urinary kynuremc acid (KA), XA and VA. Compared to men in a previous study, women excreted a greater percentage of B6 intake as 4PA, had lower plasma PLP and greater amounts of postload urinary tryptophan metabolites. At least 0.020 mg B6/g protein was required for adequate status. In a fourth study, nine women were fed diets with a high (27%) or low (9%) percentage of the B6 intake as pyridoxine glucoside, a form known to have reduced bioavailability, for 18 days each. Urinary 4PA and UB6, plasma TB6 and red blood cell PLP were significantly lower, and fecal B6 was significantly higher during the high PNG diet. The decrease in B6 status indicators on the high PNG diet suggested a loss of 15 to 18% of the total B6 intake. Taking into account bioavailability and gender differences in the effect of dietary protein, and including a safety margin, the RDA for B6 for women should be at least 0.020 mg/g dietary protein. / Graduation date: 1996

Rice consumption is responsible for the largest dietary contribution of inorganic arsenic. In addition to the direct human health impact of arsenic, arsenic toxicity impacts on rice yield. Thus two issues must be addressed: rice sensitivity to arsenic and the contribution of rice towards dietary arsenic. The grass Holcus lanatus achieves arsenate tolerance through the constitutive down regulation of phosphate transporters, which facilitate arsenate uptake. To gain a better understanding of mechanisms underlying arsenic sensitivity in rice and determine if phosphate uptake was responsible for differential arsenic sensitivity between two rice cultivars (Azucena and Bala) an experiment was undertaken examining the role of phosphate in rice arsenic sensitivity. Although high phosphate treatments were found to provide protection against both arsenate and arsenite toxicity and the two cultivars were found to respond differently to phosphate induced protection, the mechanism underlying reduced arsenic sensitivity did not appear to be controlled through a reduced phosphate uptake system. Attempts to link lab-based arsenic sensitivity of various rice cultivars to published biomass and tissue arsenic concentrations of rice grown in the field is presented. No consistent trend was identified across field sites although two negative correlations at two different sites were found (grain arsenic concentrations and shoot dry weight plotted against arsenate sensitivity). These data demonstrated the importance environment influence on traits examined. These correlations suggest that breeding for more arsenic resistant rice strains may increase plant yield but inadvertently lead to an increase in grain arsenic. Finally, QTL mapping and genome-wide association mapping were used to identify genomic regions and candidates genes responsible for variations in shoot arsenic concentrations in rice. The purpose of which was to offer a better understanding of the mechanisms responsible for this variation. Unfortunately the QTLs revealed were not reproduced in the association mapping study. A list of potential positional candidate genes are summarised and functional candidates identified and discussed.