Cu is an important trace element in living systems, including animals. It is a part of many enzymes responsible for different processes occurring in the body. However, antagonists can severely decrease the amount of Cu available to the animal, which results in numerous health issues caused by Cu deficiency. The main antagonists of the Cu are thiomolybdates whose effect is especially harsh in ruminants due to their high potential to synthesize these compounds. Thiomolybdates (the ions MoOxS4-x2- ,where x = 0-3) are formed in the rumen from molybdate and sulfide (from degradation of sulfate), both of which come from the food and water ingested by the animal.<p> The first part of the project described in this thesis was to develop reproducible preparative methods of CuTM samples in solution and solids, under conditions as biologically relevant as possible. This crucial information is missing in the literature related to Cu deficiency. The second part studied the structure of the adduct formed between Cu and two of the thiomolybdates: tetrathiomolybdate, TM4 and trithiomolybdate, TM3, as these are the most important in Cu deficiency.<p> In solution, the appropriate solution medium and the concentration of reactants were chosen to study the stoichiometry of Cu:TM in solution before precipitation occurs.<p> Conditions for preparation of solid CuTM adducts were chosen to obtain the amount of solid necessary for further studies and to eliminate the formation of unwanted side-products. In the solid phase, the stoichiometry of Cu:TM was investigated by elemental analysis. EPR spectroscopy of solid CuTM samples revealed the presence of diamagnetic species which were partially identified.<p> EXAFS studies were performed on both the Mo and Cu K edges. Spectra defined the oxidation states of both main metal atoms, Cu and Mo. Fitting of the measured EXAFS spectra of solid CuTM samples prepared at three different Cu:TM ratios determined the interatomic distances involved in these compounds. This data was used to determine the structure of the CuTM units which polymerize to form the final product. IR spectroscopy was also used to confirm the presence of some of the groups in these adducts.<p> All the results from the various spectroscopic techniques were then combined to proposed a complete reaction scheme for the two-step formation of the CuTM4 and CuTM3 adduct species.

Marginal zinc deficiency (MZD) exists in children of industrialized societies and can impair growth and development. Presently there are no data available on its global prevalence. It is believed that MZD is one of the most common hidden deficiencies throughout the world. This is partly because of the lack of sensitivity and specificity of serum zinc, the most commonly used biomarker of zinc status, to detect MZD. This deficiency in children is always accompanied by a decrease in hair zinc. Although in research settings hair zinc is a recognized biomarker of MZD in children, health practitioners do not presently use it. These cross-sectional studies were designed to examine the hair zinc status of preschoolers in Vancouver. They also aimed at exploring some dietary and non-dietary factors associated with hair zinc status in an attempt to construct and validate a screening tool for detection of MZD. Our first study indicated a mean hair zinc of 75��30 ��g/g, with 46% below the cutoff (<70��g/g) for a group (n=87) of low-income preschoolers (Chapter II). Among these children we observed negative associations between the hair zinc and consumption of dairy (R�� =0.09, P=0 .01) and milk (R�� =0.08, P=0.01), being described as "often sick" (R�� =0.55, P=0 .00) and "eating unhealthy" (R�� =0.16 P=0.00), and prolonged breastfeeding (R�� =0.11, P=0.01). Our citywide survey (n=719) indicated a mean hair zinc of 116��43 ��g/g with 17% below the cutoff (Chapter III). Logistic regression analysis indicated sex, age, maternal education, the number of adults at home, consumption frequency of milk, "scores of activity level", "being described as frequently sick" and "taking supplements containing iron" as the significant predictors of hair zinc status. However, the final model had 16% sensitivity while having 98 .3% specificity, indicating its lack of usefulness as a screening tool. Our study provides important information on the hair zinc status of Vancouver preschoolers. Although we did not accomplish our primary goal of constructing and validating a screening tool, we did identify some factors in children and their environment associated with hair zinc, which may help in better understanding of hair zinc as a biomarker of MZD.

Cu is an important trace element in living systems, including animals. It is a part of many enzymes responsible for different processes occurring in the body. However, antagonists can severely decrease the amount of Cu available to the animal, which results in numerous health issues caused by Cu deficiency. The main antagonists of the Cu are thiomolybdates whose effect is especially harsh in ruminants due to their high potential to synthesize these compounds. Thiomolybdates (the ions MoOxS4-x2- ,where x = 0-3) are formed in the rumen from molybdate and sulfide (from degradation of sulfate), both of which come from the food and water ingested by the animal.<p> The first part of the project described in this thesis was to develop reproducible preparative methods of CuTM samples in solution and solids, under conditions as biologically relevant as possible. This crucial information is missing in the literature related to Cu deficiency. The second part studied the structure of the adduct formed between Cu and two of the thiomolybdates: tetrathiomolybdate, TM4 and trithiomolybdate, TM3, as these are the most important in Cu deficiency.<p> In solution, the appropriate solution medium and the concentration of reactants were chosen to study the stoichiometry of Cu:TM in solution before precipitation occurs.<p> Conditions for preparation of solid CuTM adducts were chosen to obtain the amount of solid necessary for further studies and to eliminate the formation of unwanted side-products. In the solid phase, the stoichiometry of Cu:TM was investigated by elemental analysis. EPR spectroscopy of solid CuTM samples revealed the presence of diamagnetic species which were partially identified.<p> EXAFS studies were performed on both the Mo and Cu K edges. Spectra defined the oxidation states of both main metal atoms, Cu and Mo. Fitting of the measured EXAFS spectra of solid CuTM samples prepared at three different Cu:TM ratios determined the interatomic distances involved in these compounds. This data was used to determine the structure of the CuTM units which polymerize to form the final product. IR spectroscopy was also used to confirm the presence of some of the groups in these adducts.<p> All the results from the various spectroscopic techniques were then combined to proposed a complete reaction scheme for the two-step formation of the CuTM4 and CuTM3 adduct species.

The roles of phosphorus (P) starvation on the induction of intracellular acid phosphatase (ACP; EC 3.1.3.2) activity have been studied in a marine macroalga Ulva lactuca L. In comparison to creasy and dark green appearance in P-sufficient thalli (100 mM NaH2PO4), P-starved thalli (1 mM NaH2PO4) showed less crease and light green appearance. On exposure to 1 mM NaH2PO4, the growth rate, the contents of SRP, PP and P, and tissue C:P and N:P molar ratio decreased at day 3 and the contents of SNRP, TSP and polyphosphate decreased immediately. Intracellular ACP activity increased at day 3 after exposure to 1 mM NaH2PO4 and reached 16 folds of P-sufficient thalli at day 14, while extracellular alkaline phosphatase (AP; EC 3.1.3.1) activity increased at day 2 and reached the plateau after 4 days. Activity staining both on Native PAGE and IEF gel showed the induction of 10 and 9 ACP isoenzymes, respectively. Changes in intracellular ACP and extracellular AP activities were negatively correlated with SRP, SNRP, PP and P contents. After transferred to 100 mM NaH2PO4, the growth rate of 10 day-starvated thalli recovered after 5 days, the contents of SRP¡BSNRP¡BTSP and P, and the C:P and N:P molar ratio recovered to the level of P-sufficient thalli at day 1. When recovered to 100 mM NaH2PO4, extracellular AP activity of 10 day-starvated thalli decreased at day 2 and reached the minimum after day 8, while intracellular ACP activity decreased at day 3 and reached the minimum after day 8. The analog of Pi, Phi (1 mM) inhibited the intracellular ACP and extracellular AP activities induced by P swtarvation. The results of present investigation show that ACP has a role in the enhancement of P availability in U. lactuca via the enzymatically degradation of polyphosphates and organic P when suffers P deficiency.

Thesis PlanA (M.S.)--University of Wisconsin--Stout, 2009. / Includes bibliographical references.

Thesis--M. Med. Sc., University of Hong Kong, 1984.

Thesis (Ph. D.)--University of Hong Kong, 1984.

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vii, 56 p. Vita. Includes abstract. Includes bibliographical references (p. 41-45).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vii, 104 p. Vita. Includes abstract. Includes bibliographical references (p. 68-72).

Objective：Low vitamin D has been implicated in the development of type 2 diabetes. However, whether vitamin D continues to have a clinically significant effect in existing diabetes is unclear. The objective of this study was to examine the association of serum vitamin D with glycemic control in established type 2 diabetes. Methods: This was a retrospective analysis of medical records. Characteristics of 487 patients with type 2 diabetes were stratified by vitamin D status and serum glycosylated hemoglobin (HbA1c). Vitamin D deficiency among the subjects was studied. The relationship between vitamin D and glycemic control was explored by multiple linear regression, multivariate analysis of variance (MANOVA) and chi-square test. Patients were stratified into overweight and non-overweight group based on body mass index (BMI), and the association of serum vitamin D concentration with glycemic control was evaluated in each group. Insulin resistance and C-peptide as mediators between vitamin D and HbA1c was tested. The impact of vitamin D on cholesterol metabolism was also assessed. Results: (1) Vitamin D deficiency was highly prevalent, accounting for 88.3% of the study sample. (2) Serum vitamin D levels were significantly inversely associated with serum HbA1c. This correlation was stronger in overweight group than in non-overweight group. There was no significant relationship between serum vitamin D levels and fasting plasma glucose (FPG). HbA1c was significantly lower in vitamin D insufficiency group than in vitamin D severe deficiency group. (3) Insulin resistance partially mediated the association between vitamin D and HbA1c. (4) No significant association of Vitamin D with low density lipoprotein (LDL) or high density lipoprotein (HDL) was found in this study. Conclusions: There was an inverse association between serum vitamin D levels and HbA1c. The inverse correlation of serum vitamin D level and HbA1c was stronger in overweight group than in non-overweight group, which indicates patients with obesity might benefit more from vitamin D supplementation. / published_or_final_version / Public Health / Master / Master of Public Health