Exogenous zinc has been shown to alter the cellular response to inflammatory conditions. Both common zinc salt and novel zinc compounds have been shown to be therapeutic in various disease states. However, little is known about their action on immune cells in these conditions. This thesis aims to investigate the effectiveness of zinc monoglycerolate (ZMG), a novel zinc compound, in providing bioavailable zinc. This study also aims to examine the effect of zinc on the inflammatory responses of immune and gastric cells. Using cell culture techniques, fluorescence microscopy and inductively coupled plasma mass spectroscopy (ICP-MS), comparison was made of zinc bioavailability from ZMG, zinc oxide and zinc sulphate. The cellular protein interactions of the zinc provided by these compounds was investigated by autoradiography, Western blot analysis and cytokine assay. As a result of the biological study, chemical analyses were carried out on ZMG using high performance liquid chromatography (HPLC), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and matrix assisted laser desorption ionisation time of flight (MALDI-ToF).The result of the cell culture study indicated that ZMG and zinc oxide provided significantly more bioavailable zinc than zinc sulphate. Furthermore, these results showed that the different cell lines examined treated the zinc in distinctly different manners. The studies on direct zinc-protein interactions did not conclusively determine whether such interactions occurred between cytoplasmic proteins and exogenous zinc. However, zinc was shown to modulate cytokine secretions in vitro in cultured cell lines. The chemical analyses provided novel observations about the polymeric structure of ZMG and its solubility profile. In conclusion the results showed that ZMG is a highly effective source of bioavailable zinc and that exogenous zinc can modulate the immune response of cultured cell lines to external stimuli.

Agricultural runoff is a major non-point source of phosphorus (P) and nitrogen (N) in aquatic environments and often contributes to coastal eutrophication. Chemical extraction techniques that measure P and N in runoff and sediments have provided little information on biologically available P and N, particularly when soils/sediments move from an agricultural setting to freshwater, estuarine and marine systems. The aims of this thesis were to a) develop algal bioassay techniques for assessing bioavailability of P in marine and freshwater sediments, b) apply algal bioassays to determine the role of suspended sediments as P and N sources c) examine how sediment type and sediment load affect P bioavailability and identify the chemical analysis of soil P that best reflects bioavailable P, and d) determine nutrient bioavailability of agricultural soil runoff in estuarine and coastal marine ecosystems. An accurate and repeatable sediment bioassay was developed using non-axenic uni-algal cultures of the euryhaline diatom Skeletonema costatum and freshwater chlorophyte Selenastrum capricornutum. Bioassays were conducted in 250 mL Erlenmeyer flasks, with 100 mg L-1 of simulated sediment and 100 mL of modified growth media, which were continuously shaken. Suspended sediments were simulated from 7 major soil types of the Maroochy River catchment in Australia, a coastal catchment influenced by agriculture. Simulated sediments were used as the sole P source in replicate batch 7-14 d bioassays in which changes in in vivo Chl a fluorescence were measured. Maximum algal biomass in bioassays was significantly correlated to total sediment P content of the added sediment in marine and freshwater. Bioassay methodology was adapted to assess N as well as P bioavailability in simulated suspended sediments using Skeletonema costatum. S. costatum biomass was significantly influenced by sediment type and correlated with the Total P content of the sediment. Conversely, S. costatum response did not correlate to total nitrogen (TN), ammonium (NH4+), nitrate (NO3-) and easily mineralisable N content of the sediment. Sediment type did significantly influence response, suggesting that sorption/desorption properties of the sediment influenced N bioavailability. Suspended sediments appear to be a significant source of bioavailable P as S. costatum biomass was enhanced by their addition. Conversely, the lack of stimulation by sediments when used as a N source implies that suspended sediments are not an immediate source of bioavailable N, although they do contribute to the sediment nutrient pool once deposited. The influence of sediment type and sediment load on phosphorus (P) bioavailability was compared using Skeletonema costatum bioassays. The amount of sediment and associated P load influenced the maximum algal biomass reached, with low sediment loads (&lt 100 mg L-1) capable of stimulating high algal biomass. Maximum algal biomass correlated with sediment iron-oxide extractable inorganic P (FeO-P) and inorganic P (Pi) extracted by sodium bicarbonate for all sediment types. Total P (TP) did not discriminate at low TP concentrations and organic P (Po) extracted by sodium bicarbonate only correlated with algal biomass when bioavailable P was low. Thus FeO-P and Pi are the most representative analyses of bioavailable P. FeO-P can also be used to accurately measure rate of sediment P desorption, which significantly influences algal growth rate. Nutrient bioavailability of agricultural soil runoff was investigated in the Maroochy River catchment in southeast Queensland Australia, a coastal catchment influenced by agriculture. Suspended sediments, river and estuarine sediments and deposited sediment in the near-shore coastal zone were collected and analysed for nutrient bioavailability using chemical analyses and S. costatum bioassays. Suspended sediments in the Maroochy River, which consisted of silt and clay sized particles, had elevated FeO-P and TP concentrations comparable to fertilised soil. Similarly the deposited sediment sampled offshore to the river mouth had elevated total P, FeO-P and total N concentrations which were much greater than the underlying marine sediment. The deposited offshore sediment contained mainly silt sized particles and appeared to be terrigenous in origin as it was more similar in composition (TP, FeO-P, TN, total carbon, total aluminium, total iron, total silica) to estuarine suspended sediments and terrestrial soils, than the underlying marine sediment. This study demonstrated that fine silt sized particles, rich in bioavailable P and N, are being transported and deposited offshore during erosion events. These findings highlight the importance of effective land management and erosion control measures that reduce the suspended sediment load. Although agricultural practices are continually improving to reduce soil erosion, practices need to encompass a broader approach that emphasizes the link between land and sea. Effective management must consider agricultural productivity as well as the environmental impact or ‘algal bloom potential’ that a soil may have when eroded into a waterway. Soils high in bioavailable nutrients must be targeted and managed effectively, particularly in areas prone to erosion.

Magister Scientiae Dentium - MSc(Dent) / High caries burden coupled with a lack of water and salt fluoridation make it imperative that toothpastes marketed to the South African consumer demonstrate adequate caries inhibition. It is generally accepted that an effective toothpaste contain between 1000ppm and 1500ppm total fluoride (TF) and that of this at least 1000ppm F should be in free available form. Studies conducted in other countries have demonstrated that toothpastes often do not conform to this regulation, indicating the need for quality assessments to be undertaken. Objectives: This study therefore aimed to determine total and free available (potentially bioavailable) fluoride concentrations in 28 adult, fluoridated toothpastes marketed to the South Africa consumer. Labeling practices were also assessed. Materials & Methods: Convenience samples were purchased from a major pharmaceutical and food retailer located in each of the five metropolitan areas of South Africa. Information detailed on the packaging was evaluated for compliance with national standards. Total and bioavailable fluoride concentrations were determined potentiometrically, in quadruplicate, following acid hydrolysis of the samples using a Combination Fluoride Ion Selective Electrode, calibrated with standards containing 0.0625ppm F to 6.25ppm F. Results: Although TF content on analysis was found to be statistically significantly lower than manufacturer declaration (1.2x10-7; p≤0.05), 78.6% still contained adequate free, available F levels. Relative mean available fluoride content for toothpastes formulated with a calcium-based abrasive was 85,5% as opposed to 98.7% for those containing silica. Partial alignment with national labeling statutes was observed for all toothpastes. Conclusion: Most commercially available toothpastes are adequately formulated to provide anticariogenic activity, but consumers should be advised against the use of products containing calcium. Improvements to national standards and stricter regulation of labeling practices are required.

Anion exchange methods were used to measure the percent of weakly bound and strongly bound copper in estuarine waters and agricultural drainage. Copper bound to an ion exchange resin has been operationally defined as bioavailable copper, or copper that is available for uptake by aquatic organisms. Initial laboratory testing indicated that the percent of copper bound to the resin did not differ between a freshwater solution (pH 6.5 buffered with 30 mg/L as calcium carbonate) and a saline solution (25 ppth salinity at pH 8). Adding 20 mg/L natural organic matter (NOM) to each solution lowered the amount of copper sorbed to the resin by the same amount in saline and fresh water. Varying salinity from 16 to 30 ppth did not effect % bioavailability. This indicates that the ions typically found in seawater do not compete with copper for ion exchange onto the resin. Varying initial copper concentration from 195 to 495 ppb for the given NOM content of 12.5 mg/L did not effect % bioavailability, indicating that as the copper concentration of this water is increased over the range studied, the fraction of potentially toxic copper is constant. Decreasing the pH of the system from 8.5 to 4 and the NOM from 12.5 to 0 mg/L statistically increased % bioavailability in both cases. However, copper retention onto the resin at pH values near 4 was hindered, possibly because resin functional groups become inefficient at low pH values. MINEQL+ predicted that the resin was not retaining approximately 30% Cu⁺² at a pH of 4. Copper retention to the resin was also not as high as expected at NOM contents between 0 and 3 mg/L at pH 8.1. MINEQL+ indicated that the water studied at pH 8.1 was comprised primarily of strongly bound copper-organic ligand species and Cu(OH)₂. Experimental results suggested that the resin retained only 50% Cu(OH)₂, which is a potentially bioavailable copper complex. However, MINEQL+ computer modeling indicated that the resin was accurately retaining potentially bioavailable copper in waters with a pH from 5.5 to 8.5, containing 3 to 12.5 mg/L NOM. After assessing the characteristics of copper retention by the resin, it was applied to an estuarine system and agricultural drainage to measure bioavailable copper. The results indicated that in copper-containing agricultural runoff and groundwater the percent bioavailable copper was approximately 15% of the dissolved copper. This percentage was relatively constant over the range of copper concentrations observed. In estuarine systems receiving agricultural runoff, the percent bioavailable copper was about 11%. This research was supported by a grant from the Virginia Pesticide Control Board. / Master of Science

: In freshwater systems phosphorus (P) is the limiting element in the cause of eutrophication. In many Swedish lakes, causes of eutrophication have been attributed to more of internal loading than external since the external loading has been fairly well managed. Internal loading is linked to the mobility of sediment P, which are known to be Bioavailable P (BAP). Sediments from Lake Hällerstadsjön in Sweden was studied to know the BAP concentration and its possible release into the water column under reduced conditions. Sediments were sampled at two different depths, 0-5 cm and 5-10cm. BAP was determined by a phosphorus fractionation scheme. Sediments were incubated under oxic and anoxic conditions in the laboratory to evaluate sediment P release. Spatial variation in the distribution of P forms across the lake was also studied, in order to examine possible local patterns, particularly along a transect from the main inlet to the outlet. Fractionation analyses showed a trend of; Residual-P > NaOH-P > HCl-P > BD-P > Loosely bound P. The fractions constituting the BAP was higher at the 0-5 cm sediment depth than 5-10 cm. Sediment P flux was recorded for anoxic but not oxic sediment. BAP correlated significantly with sediment P flux (P= 0.01). Spatially, the P distribution varied both at depths and along a latitudinal transect, from the main inlet to the outlet.  Dredging of the surface sediments with high BAP content would possibly be an effective means of preventing eutrophication of the lake.

The bioavailable fraction of phosphorus (BAP) in the lower Bear River system waters was investigated. BAP plays a critical role as the limiting nutrient for algal production and eutrophication in proposed reservoirs in the Bear River system. The Bear River system has a hardness rang ing between 180-240 rng/L as CaC03 which significantly affects BAP. BAP estimation was done by a modified Selenastrum capricornutum Printz Algal Assay Bottle Test. The algal bioassay is considered the best estimator of BAP because no chemical tests or i ndicator parameters are available. Autoclaving and UV radiation were found to be unacceptable means for sterilization because of phosphorus precipitation and inability to kill all the protozoa, respectively. Whole water samples were sterilized by gamma radiation . Hydrogen peroxide formed by gamma radiation was minimized by sparging with nitrogen gas , and adding peroxidase to remove low hydrogen peroxide concentrations. Soluble reactive phosphorus concentrations changed during radiation. The algal photosynthetic consumption of co2 in the assay procedure raised the pH from 8 to as high as 10, which resulted in significant quantities of phosphorus precipitating with calcium and becoming unavailable. To minimize the effects of precipitation, the following recommendations are made : (1) bubble the bioassay flask with a C02/air gas mixture to minimize pH increase ; and (2) use a high inoculum (105 cells/ml) of S . capricornutum that have been phosphorus starved for several days to maximize luxury uptake. Bioavailable phosphorus was estimated for each of the sources in Cache County. There are three major point sources (Logan, Hyrum, and Preston wastewater treatment plants) that contribute significant quantities of phosphorus . There are approximately 200 feedlots in the Cache Valley, and approximately 744,000 acres of land in Cache County which contribute runoff to the Bear River system. In Cache County, point sources contribute 2 8 , 20 0 ( 4 6%) kg BAP /yr, livestock runoff contributes 2,500 (4%) kg BAP/yr, and land runoff contributes 28,600 to 33,600 (50%) kg BAP/yr. Bioavailable phosphorus from land runoff was calculated by using export coefficients, which are usually accurate within a factor of two. A comprehensive phosphorus management plan is required to reduce available phosphorus from all sources to minimize algal blooms in the receiving waters.

Muscle foods/meat enhances bioavailability of non-heme iron form the diet. This effect is generally thought to be due to production of peptides, by gastro-intestinal digestion, which reduces/chelate the iron in upper intestine. Dialyzable iron is widely used as an in-vitro indicator of iron bioavailability, and with few exceptions, correlates well with human studies. Human studies have used cooked meat to test the effect on iron, but little attention has been given to the effects of cooking. We studied the effect of heating chicken muscle on the production of dialyzable iron. Chicken breast muscle was homogenized and heated to the temperatures in the range of 130-195oF. The concentration of amino acid binding residues was determined in the heated samples. The samples were then mixed with ferric iron and digested with pepsin and pancreatin. Heating chicken muscle caused a large drop in sulfhydryl (-SH) content and a lesser but significant loss in histidine content, both of which increased progressively with temperature. At 165oF, considered a safe cooking temperature, the loss in –SH and histidine was 75% and 37%, respectively. Changes in dialyzable iron and dialyzable ferrous iron (often considered the best indicator of bioavailability) paralleled the drop in amino acid. Raw uncooked chicken muscle produced about 11 times as much dialyzable iron and 17 times as much dialyzable iron as the control but heating to 165oF reduced the values by 47% and 74% respectively. Heating to 195oF reduced caused a further drop in dialyzable iron values. Our result showed that cooking chicken muscle caused a large decrease in the production of dialyzable iron forms-especially in the ferrous form- and this is correlated with the loss in critical iron binding amino acids.

Introdução: A deficiência de ferro decorre, principalmente, da quantidade insuficiente de ferro na dieta para atender às necessidades nutricionais do indivíduo. Seu estágio mais grave, a anemia ferropriva, é reconhecida como um problema epidemiológico da maior relevância, sendo as crianças em idade pré-escolar, especialmente os lactentes, o grupo mais vulnerável à desnutrição. Objetivo: Identificar a prática alimentar e estimar sua capacidade de atender à recomendação e à necessidade de ferro das crianças de 6 a 23 meses de idade atendidas pela Estratégia Saúde da Família no Maranhão. Métodos: Estudo transversal de base populacional realizado no estado do Maranhão. A partir dos dados de consumo referido (inquérito recordatório de 24h), foram identificadas as práticas alimentares e calculadas quantidades de ferro, vitamina C e de energia a partir dos quais se quantificou o ferro biodisponível utilizando a equação de Monsen e Balintfly. Estimaram-se, ainda, as densidades do ferro total e do ferro biodisponível, além da adequação às recomendações da OMS. Resultados: Do total de 401 crianças estudadas, 7 crianças permaneciam em aleitamento materno exclusivo e dentre aquelas em que foi referida a alimentação complementar, o leite materno esteve presente entre 53 por cento delas, mesmo com a introdução do leite de vaca. A quantidade média de energia foi 826 kcal; ferro total 5,4 mg; ferro biodisponível 0,31 mg; densidade de Ferro/1000kcal= 6,4 e densidade de Ferro biodisponível/1000kcal= 0,34. Em comparação às recomendações, a ingestão energética apresentou valores abaixo da recomendação para mais de 50 por cento da população de estudo, em todas as faixas etárias, já em relação ao ferro, a partir dos 15 meses pelo menos 60 por cento das crianças alcançam a recomendação. Conclusão: A prática alimentar não se mostrou adequada para atender à recomendação e à necessidade de ferro diária, o que pode ser explicado pelo baixo consumo de alimentos fontes de ferro, com boa biodisponibilidade do mineral e de alimentos estimuladores de sua absorção. / Introduction: Iron deficiency is mainly due to the insufficient amount of iron in the diet to meet the nutritional needs of the individual. Its most severe stage, iron deficiency anemia is recognized as an epidemiological problem of the greatest importance, being the children of preschool age, especially infants, the group most vulnerable to malnutrition. Objective: To identify eating habits and estimate their ability to meet the recommendation and the need of iron for children 6-23 months of age served by the Family Health Strategy in Maranhão. Methods: Sectional study population-based study conducted in the state of Maranhão. From the data of consumption above (R24h), dietary practices and calculated amounts of iron, vitamin C and energy were identified from which the bioavailable iron was quantified using the equation of Monsen and Balintfly. Were estimated, furthermore, the densities of total iron and bioavailable iron, as well as compliance with WHO recommendations. Results: Of the 401 children studied, seven children remained in exclusive breastfeeding and among those that was reported complementary feeding, breast milk was present among 53per cent of them, even with the introduction of cow\'s milk. The average amount of energy was 826 kcal; Total Iron 5.4 mg; bioavailable iron 0.31 mg; density of Iron / 1000 kcal = 6.4 and density of bioavailable iron / 1000 kcal = 0.34. Compared to the recommendations, energy intake showed values below the recommendation for more than 50per cent of the study population in all age groups, as compared to iron, from 15 months at least 60per cent of children reach the recommendation. Conclusion: A diet was not adequate to meet the recommendation and the need for daily iron, which can be explained by low consumption of iron-rich foods with good bioavailability of the mineral-stimulating food absorption.

Introdução: A deficiência de ferro decorre, principalmente, da quantidade insuficiente de ferro na dieta para atender às necessidades nutricionais do indivíduo. Seu estágio mais grave, a anemia ferropriva, é reconhecida como um problema epidemiológico da maior relevância, sendo as crianças em idade pré-escolar, especialmente os lactentes, o grupo mais vulnerável à desnutrição. Objetivo: Identificar a prática alimentar e estimar sua capacidade de atender à recomendação e à necessidade de ferro das crianças de 6 a 23 meses de idade atendidas pela Estratégia Saúde da Família no Maranhão. Métodos: Estudo transversal de base populacional realizado no estado do Maranhão. A partir dos dados de consumo referido (inquérito recordatório de 24h), foram identificadas as práticas alimentares e calculadas quantidades de ferro, vitamina C e de energia a partir dos quais se quantificou o ferro biodisponível utilizando a equação de Monsen e Balintfly. Estimaram-se, ainda, as densidades do ferro total e do ferro biodisponível, além da adequação às recomendações da OMS. Resultados: Do total de 401 crianças estudadas, 7 crianças permaneciam em aleitamento materno exclusivo e dentre aquelas em que foi referida a alimentação complementar, o leite materno esteve presente entre 53 por cento delas, mesmo com a introdução do leite de vaca. A quantidade média de energia foi 826 kcal; ferro total 5,4 mg; ferro biodisponível 0,31 mg; densidade de Ferro/1000kcal= 6,4 e densidade de Ferro biodisponível/1000kcal= 0,34. Em comparação às recomendações, a ingestão energética apresentou valores abaixo da recomendação para mais de 50 por cento da população de estudo, em todas as faixas etárias, já em relação ao ferro, a partir dos 15 meses pelo menos 60 por cento das crianças alcançam a recomendação. Conclusão: A prática alimentar não se mostrou adequada para atender à recomendação e à necessidade de ferro diária, o que pode ser explicado pelo baixo consumo de alimentos fontes de ferro, com boa biodisponibilidade do mineral e de alimentos estimuladores de sua absorção. / Introduction: Iron deficiency is mainly due to the insufficient amount of iron in the diet to meet the nutritional needs of the individual. Its most severe stage, iron deficiency anemia is recognized as an epidemiological problem of the greatest importance, being the children of preschool age, especially infants, the group most vulnerable to malnutrition. Objective: To identify eating habits and estimate their ability to meet the recommendation and the need of iron for children 6-23 months of age served by the Family Health Strategy in Maranhão. Methods: Sectional study population-based study conducted in the state of Maranhão. From the data of consumption above (R24h), dietary practices and calculated amounts of iron, vitamin C and energy were identified from which the bioavailable iron was quantified using the equation of Monsen and Balintfly. Were estimated, furthermore, the densities of total iron and bioavailable iron, as well as compliance with WHO recommendations. Results: Of the 401 children studied, seven children remained in exclusive breastfeeding and among those that was reported complementary feeding, breast milk was present among 53per cent of them, even with the introduction of cow\'s milk. The average amount of energy was 826 kcal; Total Iron 5.4 mg; bioavailable iron 0.31 mg; density of Iron / 1000 kcal = 6.4 and density of bioavailable iron / 1000 kcal = 0.34. Compared to the recommendations, energy intake showed values below the recommendation for more than 50per cent of the study population in all age groups, as compared to iron, from 15 months at least 60per cent of children reach the recommendation. Conclusion: A diet was not adequate to meet the recommendation and the need for daily iron, which can be explained by low consumption of iron-rich foods with good bioavailability of the mineral-stimulating food absorption.

Water, sediments, floodplain soils, and fish from Big and Little Bayou creeks were assessed for polychlorinated biphenyls (PCBs) and metals in 1987-2005. The streams were impacted by effluents from the Paducah Gaseous Diffusion Plant (PGDP). PCBs were rarely detected in water samples. Aroclor 1248 detections in sediments and floodplains were sporadic, but 1254 and 1260 were consistent. Seasonal variations were only observed for Aroclor 1248. Detection of PCBs in floodplains indicated recent influx of contaminated sediments. Species-specific PCB residues patterns were studied for Lepomis cyanellus, L. megalotis, L. macrochirus, and Campostoma anomalum. Highest PCB concentrations were found in stoneroller minnows. PCBs decreased over time in sunfish species, but retained a baseline level. No relationships were found between sunfish age and PCB concentrations. At low PCB levels, green sunfish body burden (BB) did not correlate with lipid content. A certain PCB concentration must be exceeded before PCB BB correlates with lipid content. Stream flows differed by season, and fish PCB BB differed by season, but stream flow did not correlate with fish BB. Congener groups corresponded to Aroclor concentrations. Higher chlorinated biphenyls peaked in the spring for sport fish. PCBs remobilized in the spring resulted in higher summer BB for the stoneroller minnows, whereas sunfish eliminated PCBs by summer. This variability was due to the sunfishs ability to regulate PCBs. Metal concentrations did not display the seasonal variability evident in the PCB data. Water metals may have peaked during storm events and decreased rapidly. Water Pb increased with time, but the source could not determined. Zinc in Little Bayou creek likely originated from the PGDP. Except for Cu and Zn, stoneroller minnow metal BB decreased with time. Metal BB were used to determine bioavailable fractions. Less than half of the water column Cd, Cr, Fe, and Pb in impacted areas were bioavailable to stoneroller minnows, whereas 59% of Ag, 73% of Cu, and 64% of Zn were bioavailable. Cumulative criterion units were calculated to determine additive metal impacts, and proved useful in locating sectors with possible ecological impact. In-situ monitors proved valuable in studying PCB and metal behavior under real-world conditions.