This purpose of this study was to determine the effects of vitamin E and/or resistance exercise on insulin resistance and glucose uptake. Nine subjects, who were currently active but not strength training, were assigned to either the vitamin E or placebo group based on their prescreening measurements. Subjects underwent a 3-week vitamin E washout period before testing. At baseline testing subjects were given a 75-gram glucose load and blood was drawn every 15-minutes for 2-hours to analyze insulin and glucose response. Another oral glucose tolerance test (OGTT) was performed 45minutes after a 50-minute full body progressive resistance training session to determine insulin and glucose response to exercise. Subjects ingested either the placebo (3 capsules of olive oil) or 1200 IU vitamin E (3 capsules) for 9-weeks. After 3-weeks of supplementation the subjects returned for another exercising OGTT. After this session the subjects began a 6-week progressive resistance exercise program, in which they performed another OGTT after the last session. Both groups showed a significant increase in strength gains pre and post resistance training. The statistical analysis failed to demonstrate any differences between groups in insulin or glucose response in any of the four OGTT trials, but there were multiple trends present. Combining vitamin E supplementation with resistance training increased insulin sensitivity and the disposal of glucose. Both groups also had significant strength gains from pre to post study. Future research is needed for verification of these trends. / School of Physical Education

Ascorbic acid has been found to promote nitrosothiol decomposition via two pathways. In the first, ascorbic acid acts as a reducing agent for added or adventitious copper (II), producing copper (I). This reacts with the nitrosothiol, giving nitric oxide and disulfide as the ultimate products. The reaction requires only small quantities of ascorbic acid, and is catalytic in copper. The second pathway requires higher concentrations of ascorbic acid, the stoichiometry being one mole of ascorbic acid to two moles of nitrosothiol. The products are nitric oxide and thiol, and the reaction has been interpreted in terms of rate limiting nucleophihc attack by ascorbate at the nitroso nitrogen, followed by decomposition of the 0-nitroso ascorbate formed to nitric oxide and dehydroascorbic acid. The rate equation is first order in both the nitrosothiol and ascorbic acid, and the entropy of activation is significantly negative. pH - rate profiles reveal the ascorbate dianion is much more reactive than the monoanion, and that the neutral form has negligible reactivity. Nitrosation of thione-containing nitrogen heterocycles by nitrous acid leads to the equilibrium formation of =SNO(^+) species; large equilibrium constants are observed. The reactions exhibit many of the features generally observed in nitrosation, including catalysis by halides and thiocyanate, and some participation by dinitrogen trioxide as a nitrosating agent. The nitrosation rate constants are large, approaching values representing the encounter-controlled limit. The =SNO(^+) species are generally unstable, decomposing under acidic conditions to nitric oxide and a disulfide. Decomposition of S-nitrosated 4-thiopyridine showed hydrolysis occurs at pH 7.4, re-forming the thione. The nitroso species reacts rapidly with ascorbate, forming nitric oxide and thione.

Commercially bottled, vitamin C-fortified, cranberry juice cocktail and cranberry-apple (cranapple) juice drinks were stored at 5°C under simulated home-use conditions. Ascorbic acid (AA) and dehydroascorbic acid (DHA) levels were evaluated over a period of seven days by high performance liquid chromatography (HPLC). Total vitamin C content was also determined by a classical spectrophotometric method. The HPLC data revealed a significant decrease of AA during the storage of both juice drinks resulting in losses of 35% and 27% in the cranberry and cranapple drinks, respectively. The loss of ascorbic acid was offset by the simultaneous increase of DHA (a biologically active vitamin) so that the sum of AA+DHA decreased 13% and 0% in the cranberry and cranapple drinks, respectively. Thus ascorbic acid retention was apparently influenced by the nature of the juice system. The spectrophotometric results indicated no significant loss of total vitamin C activity during the storage of either juice drinks. The observed differences between the spectrophotometric and HPLC results were attributed to interference problems associated with the spectrophotometric method. / Graduation date: 1988

We compared a kinetic method (KM) and a colorimetric method (CM) for measuring erythrocyte aspartate aminotransferase (EAST) activity. Twenty-three healthy college students including 7 men and 16 women, aged from 22 to 40 years, participated in this study. Vitamin B-6 status was assessed by EAST activity coefficient (EAST-AC), the ratio of EAST stimulated activity by adding PLP in vitro (EAST-SA) to basal activity (EAST-BA). These subjects' EAST indices (EAST-BA, EAST-SA and EAST-AC) were compared to their plasma PLP concentration and their dietary intake of vitamin B-6 as determined by the food frequency questionnaire (FFQ) and 3-day dietary record. There was a significant correlation (r=0.59, p<0.01) in EAST-BA obtained by the two methods, while the correlation of EAST-SA values between the two methods was not significant (r=0.40, p=0.06). EAST-AC obtained with KM was linearly associated (r=0.57, p<0.01) to EAST-AC obtained with CM, but was 1.26 times higher (p<0.01) than that with CM. Thus, the method used for the determination of the normal EAST-AC value needs to be noted. None of EAST indices measured were significantly correlated with plasma PLP concentration. There was a high correlation for vitamin B-6 intake (r=0.65, p<0.01) and the ratio of vitamin B-6 to dietary protein (r=0.58, p<0.01) estimated between the FFQ and the 3-day dietary record. The results suggested the high validity of the FFQ for determining vitamin B-6 intake. Neither of these dietary methods was, however, correlated with any EAST activity indices or the plasma PLP concentration. / Graduation date: 1995

Graduation date: 1991

Graduation date: 1943

Graduation date: 1980

In der Vitamin A-Forschung spielen Tiermodelle eine wichtige Rolle. Das am häufigsten verwendete Tiermodell in der VA-Forschung sind Ratten, die wie der Mensch einen spezifischen VA-Transport durch das Retinol-Bindungsprotein (RBP) im Blut besitzen. Im Gegensatz dazu wurden Frettchen bisher nur in der Carotinoidforschung eingesetzt. Die Frettchen besitzen aber hinsichtlich des VA-Stoffwechsels physiologische Ähnlichkeiten mit anderen Fleischfressern. Bei Fleischfressern existiert neben dem spezifischen VA-Transport durch das RBP auch ein unspezifischer VA-Transport durch Lipoproteine des Blutserums. Dadurch könnten Frettchen ein geeignetes Tiermodell für Studien zum unspezifischen VA-Transport sein. Ein Vergleich von Parametern des VA-Stoffwechsels von Ratten und Frettchen könnte die physiologischen Besonderheiten dieser Tiere näher charakterisieren.

Bibliography: leaves 181-201 / 201, [ca. 75] leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1987

xxi, 215 leaves : photos, graphs, tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agricultural Biochemistry, 1979