Digitized by Kansas Correctional Industries

Typescript. / Digitized by Kansas Correctional Industries

Given the strong evidence for a beneficial role of vitamin D in diabetes and CVD pathogenesis, and the prevalence of vitamin D deficiency, vitamin D supplementation has been advocated for the prevention of cardiometabolic disease. To provide information on the effects of 5,000IU (125µg) vitamin D3 on cardiometabolic risk, a double blind, RCT in a cohort of overweight and obese UK adult males with plasma 25(OH)D concentration < 75nmol/L for a duration of 8 weeks was conducted. To the best of my knowledge, this is the first RCT to investigate the effect of 5,000IU (125µg) vitamin D3 on cardiometabolic markers in vitamin D insufficient, non-hypertensive and non-diabetic overweight and obese adult males.

Colorectal cancer (CRC) is common, with >1 million annual incidence worldwide and is associated with significant morbidity and mortality. Prevention is a particularly appealing strategy to combat CRC, but there is a paucity of well-founded mechanistic research in the area. CRC is a complex disorder, with both genetic and environmental factors influencing incidence. The heritable component of CRC variance is estimated to be ~35%, with ~5% due to highly penetrant mutations. Common genetic variance likely makes up the majority of the heritable component, yet a large proportion of heritability remains unexplained. One possible explanation is gene-environment interactions (GxE) where-by both genetic and environmental factors interact to influence risk. Observational data implicate vitamin D as an environmental risk factor in CRC aetiology and in-house data indicates that genotype at the GWAS identified CRC risk locus rs9929218 influences this association, i.e. a GxE. The rs9929218 locus is intronic within CDH1, a tumour suppressor gene, and present evidence suggests a gene-environment interaction model of vitamin D-induced CDH1 transcription dependent on genotype at the rs9929218 locus and mediated by VDR and FOXO transcription factors and SIRT1, a FOXO regulator. To test this model, two broad approaches were employed - an observational approach to assess the association between human plasma vitamin D status, rs9929218 genotype and normal colorectal mucosa CDH1 expression and an interventional approach treating cell lines, organoids and human subjects with vitamin D to assess genotype-specific effects. Observational analysis of vitamin D level (25OHD) in CRC cases identified a significant influence of age, gender, BMI and selected vitamin D pathway genetic variation, while analysis of 424 normal colorectal mucosa samples from CRC cases and cancer-free subjects demonstrated strong sampling, gender, age and site differences in gene expression. 25OHD was not significantly associated with mucosa gene expression at individual gene level. However, association with a number of pathways relevant to tumourigenesis, including 'cell adhesion', 'migration' and 'cell death' was seen, providing possible mechanism to the published observational data. Circulating 25OHD level was not associated with mucosa CDH1 expression, yet crucially, analysis demonstrated a strong additive gene-environment interaction effect between plasma 25OHD, the rs9929218 genotype and NM expression of VDR, FOXO and SIRT1 explaining ~70% of the variance of mucosal CDH1 expression. The interventional approach first investigated vitamin D effects on CRC cell lines and human colorectal mucosa organoids. Calcitriol, the active form of vitamin D, induced CDH1 expression in 4 CRC cell lines, with interaction effects explaining 66% of the variance of CDH1 expression. CDH1 induction was replicated in human colorectal epithelial organoids, a non-aberrant tissue model, while gene enrichment analysis from both cells and organoids implicate vitamin D in a number of processes relevant to CRC tumourigenesis including regulation of cell proliferation, differentiation, migration and apoptosis, consistent with the pleiotropic effects of vitamin D reported in the published literature. Finally, a novel human intervention study was undertaken to investigate the impact of vitamin D supplementation in human blood and rectal mucosa. Short-term high-dose supplementation of 50 participants significantly induced CDH1 expression in rectal mucosa, with significant gene interaction effects between 25OHD, rs992818 genotype and CDH1, VDR and FOXO expression, thus independently replicating the same gene interaction effects seen in the human observational study. Meanwhile, transcriptome profiling identified numerous pathways relevant to tumourigenesis significantly enriched after supplementation, validating several pathways also associated with vitamin D status in the observational study. In summary, the research presented in this thesis demonstrates that vitamin D treatment of cells, epithelial organoids and human subjects induces CDH1 expression, and that strong gene interaction effects involving the colorectal cancer risk locus rs9929218 modulate this effect. FOXO transcription factors influence the gene interaction effect, consistent with the proposed model of ligand dependent regulation of FOXO by VDR and transcription activation of the CDH1 gene by the FOXO complex dependent on rs9929218 genotype. These data provide support for rectal CDH1 expression as an intermediate biomarker for vitamin D chemopreventive studies and suggest that gene environment interactions underlie some of the missing heritability of CRC.

Bibliography: leaves 181-201.

The blood thiamine concentration of 11 subjects was determined by means of the Friedemann and Kmieciak (1943) method every 5 days during a 30-day experimental period. Study I was conducted on 5 students in 1947 and Study II was conducted on 6 students in 1948. The subjects in both studies were on diets in which their intake of ascorbic acid only was controlled. A record was kept of each subjects food intake. The daily values for total Calories, non-fat Calories and thiamine in the diet were obtained from food tables. Non-fat Calories, the ratio of non-tat Calories to total Calories, thiamine to 1000 Calories and thiamine to non-fat Calories were calculated. The blood thiamine values for the subjects in Study I (all girls) ranged from 4.91 to 10.85 mcg per cent. There was a general decrease throughout the study in the mean intake of thiamine expressed in terms of mcg per 1000 Calories and mcg per 1000 non-fat Calories. The greater the decrease in thiamine intake in terms of mcg per 1000 non-fat Calories the greater was the loss of blood thiamine. The values for thiamine in the blood of the boys in Study II ranged from 8.00 to 15.32 mcg per cent and for the one girl in Study II from 8.35 to 13.93 mcg per cent. The blood thiamine values for the subjects in Study II did not indicate the same relationship to thiamine intake as did those in Study I. There was an increase in the concentration of the thiamine in the blood even though there was a decrease in the mean thiamine intake from the beginning to the end of the experiment. It would appear, therefore, that the boys obtained sufficient thiamine throughout the 30-day period. No data have been obtained which indicate whether or not there are variations from day to day in the concentration of thiamine in the blood when subjects are maintained on a constant intake of thiamine. A metabolism study using 5 adult women as subjects was planned in order to determine the daily values for thiamine in the blood when subjects were maintained on a controlled diet for a period of 52 days. An unpublished micro-method for the determination of thiamine in the blood developed by Dr. H. Burch (1948) was to be used. The experimental diet consisted of a basal diet providing approximately 1000 Calories and 300 mcg of thiamine with additions to the basal diet planned in units providing approximately 500 Calories and 150 mcg of thiamine. The values for protein, fat, carbohydrate and total Calories were obtained, from food tables. Non-fat Calories were calculated and the thiamine content of the food was determined by analysis. All 5 subjects ate the same food each day. In spite of the fact that considerable preliminary work was performed before the study started the blood thiamine values obtained in the nutrition laboratory were always significantly lower than results obtained by other workers. It was decided to freeze the blood samples after the protein had been removed and work on certain aspects of the method before any analyses of the blood thiamine were made. Further study of the Burch method included variation in the amounts of potassium acetate used, use of different trichloroacetic acid reagents, tests for enzyme activity, variations in the incubation procedure, variations in the procedure for the oxidation to thiochrome and in the extraction of thiochrome, reading samples sooner after transfer to optically matched tubes, variations in the irradiation procedure, use of all new reagents, use of another micro-photofluorometer, development of standard curves and the determination of the response of two subjects to an oral test dose of thiamine hydrochloride. None of these variations resulted in a solution of the problem. Suggestions for future work with the Burch method are discussed. / Graduation date: 1950

The reductive dechlorination of chlorobiphenyls in sediment by titanium(III) citrate-reduced vitamin Bus was studied in batch reactors. Long term ampoule studies demonstrated reductive dechlorination of sediment-sorbed 2,3,4,5,6-pentachlorobiphenyl (2,3,4,5,6-PeCB) to tetra-, tri-, di-, and monochlorobiphenyl products. Over 50% chlorine removal was observed over 160 days. The results of the ampoule experiment were compared to previous experiments with aqueous PCBs, and both systems appeared to follow the same pathway. Theoretical product distributions based on free energies of formation were compared to product distributions for the ampoule experiments, and both aqueous and sediment-sorbed PCB reductive dechlorination followed the thermodynamically favored pathway. Although chlorines were removed from all positions, reductive dechlorination was generally preferred at the ortho position. / Graduation date: 1999

Graduation date: 1998

Thesis (Ph. D.)--University of Washington, 1985. / Vita. Bibliography: leaves [144]-152.

There were two main purposes to this study. The first was to determine the vitamin B-6 and pyridoxine β-glucoside content of selected foods commonly consumed in Malawi. The second was to examine the effect of preparation procedures of foods in Malawi on the content of vitamin B-6 and pyridoxine β- glucoside in foods. Seventeen plant foods commonly eaten in Malawi were determined for vitamin B-6 and pyridoxine β-glucoside using a microbiological assay. In addition, two commercial weaning foods, roasted maize-soy bean blend and extruded maize-soy bean blend, were also determined for vitamin B-6 and pyridoxine β-glucoside contents. Among all the foods analyzed, whole maize flour contained the highest amount of vitamin B-6 (0.66 mg/100 g), therefore, an excellent source of vitamin B-6 content in foods. Cooking decreased vitamin B-6 in pinto beans, kidney beans, sugar beans and cow peas by 34%, 45%, 14% and 48%, respectively. Roasting decreased vitamin B-6 in chick peas and soy beans by 59% and 38%, respectively. Soaking and fermentation reduced vitamin B-6 in soaked maize flour and cassava flour by 86% and 89 %, respectively. Therefore, these data suggest that some of the preparation procedures practiced in Malawi have a negative impact on the vitamin B-6 content of the processed foods. Cooked and roasted foods contained lower total amount of pyridoxine-glucoside than that of the raw food. The high pyridoxine β-glucoside content have adverse impact on the bioavailability of vitamin B-6 content. Based on typical diets for the urban and rural populations in Malawi, the rural diet contained less vitamin B-6 compared to that of urban diet. Therefore, the rural population may be at risk of inadequate vitamin B-6 intake compared to the urban population. / Graduation date: 2002