Thesis PlanA (M.S.)--University of Wisconsin--Stout, 2006. / Includes bibliographical references.

The goal of this dissertation is to investigate the interaction between cimetidine and dietary flavonoids using the Caco-2 cell transport model. It has been shown that flavonoids can change the bioavailability of pharmaceuticals, either by inhibiting metabolizing enzymes or inhibiting the drug efflux transporters. However, the effect of dietary flavonoids in the absorption of cimetidine has not been investigated. Therefore, the hypothesis of this study is that the absorption of cimetidine is mediated by a drug efflux pump, P-glycoprotein, of which dietary flavonoids can enhance the permeability of cimetidine by reducing P-glycoprotein function. The increase in permeability of cimetidine can increase the bioavailability of cimetidine. To test the hypothesis, three objectives were proposed. The first objective was to validate the Caco-2 transport model in our laboratory. The validation was performed by measuring the electrical resistance ofthe monolayer and determining the transport of paracellular marker. Also P-glycoprotein function was determined using rhodamine 123. The second objective was to describe the transport characteristics of cimetidine in the Caco-2 cell monolayers. The permeability of cimetidine was determined at different pH environments. When the permeability of cimetidine from apical to basolateral and basolateral to apical was compared, there appeared to be an effiux mechanism involved transport of cimetidine. The permeability of cimetidine in the presence of verapamil, a P-glycoprotein competitive inhibitor, suggested that P-glycoprotein was involved in the effiux. The third objective was to study the effect of dietary flavonoids on the permeability of cimetidine in the Caco-2 cell model. In the present study, four different flavonoids, quercetin, genistein, naringenin, and xanthohumol were selected. When co-treated with flavonoid aglycones, the permeability ofcimetidine was significantly reduced in the basolateral to apical direction. However, only genistin, a glycoside of genistein, significantly reduced the efflux of cimetidine. The present studies demonstrate that some dietary flavonoids, especially aglycones, can significantly reduce the effiux of cimetidine in the Caco-2 cell monolayers. Therefore, the fiavonoids consumed in a normal diet have the potential to enhance the bioavailability of cimetidine and possibly other P-glycoprotein substrates by altering their permeability. / Graduation date: 2004

Thesis (M.S.)--Baylor University, 2009. / Includes bibliographical references (p. 65-72).

No description available.

Most Australian studies on estuarine plankton have examined distribution and abundance in relation to hydrological changes, primary productivity and associated nutrient dynamics. Relatively few have examined the complex interactions between zooplankton grazers and the type and quality of food available, or the role of zooplankton grazers in structuring phytoplankton communities, or their contribution to the nutrient pool. The ecological role of zooplankton grazers in the Swan River estuary, Perth, Western Australia, was examined as part of a collaborative research project directed by the Western Australian Estuarine Research Foundation, which was established in response to concern about increasing intensity and persistence of algal blooms. The present study focussed on one component of the zooplankton, the Copepoda, as model zooplankton grazers. A regular zooplankton monitoring programme, undertaken over a two year period, provided data on seasonal patterns of abundance and distribution of zooplankton over a broad spectrum of physical conditions. Relationships were identified between habitat variables, such as algal biomass, dissolved oxygen, salinity and suspended solids and zooplankton distribution, relative abundance and species composition. Prior to the inception of this study, it was assumed that copepod species composition, abundance and richness in the Swan River estuary may have changed over time, in response to long-term declines in water quality. Comparison of historical copepod monitoring data with current data did not detect any such change and it was concluded that there was greater variation in copepod species composition, abundance and richness within years than between years and that no significant change had occurred between 1966 and 1997. / However, an absence or reduction in abundance of copepods in areas of very high algal biomass (>80 pg chlorophyll a.L-1) suggests that local loss of water quality may have an impact on copepods over a small spatial scale within the estuary. Different aspects of the interactions between zooplankton grazers and phytoplankton were studied. Zooplankton grazing rates were measured in situ during algal blooms and in the laboratory under controlled conditions to determine the potential for zooplankton grazers to reduce algal biomass. Field and laboratory experiments supported the hypothesis that copepods and other zooplankton can exert 'top-down control' over phytoplankton biomass, but that the type and biomass of phytoplankton present affected their ability to exert this control. The results of the field and laboratory grazing experiments, along with literature data, were used to provide input data for a model of zooplankton and phytoplankton dynamics during a dinoflagellate bloom in the Swan River estuary. The model was tested against biomass measurements of zooplankton and phytoplankton to determine how well it predicted actual changes in the plankton community. The simulated output closely followed the measured Page x field data and fitted regression curves and provided information about diurnal patterns of phytoplankton production, respiration and migration and hydrodynamic transport, which was not available from field data. It was shown that zooplankton grazing, particularly grazing by microzooplankton, was the process contributing most to the observed decline in dinoflagellate biomass. Nutrient availability is one of several factors determining productivity of phytoplankton. Nutrients within copepod faecal pellets are relocated by faecal deposition to sediments, where microbial activity leads to the remineralisation of these nutrients. / Quantification of metabolic excretion of nutrients by copepods and the rate at which pellets are produced by copepod grazers, the concentration of nutrients within faecal pellets and the rate at which these nutrients are released indicated that copepods may play an important role in nutrient regeneration during summer and autumn when allochthonous nutrients are unavailable. At other times of the year, it is unlikely that copepods play an important role in nutrient regeneration. The research has provided a more detailed level of understanding of the interactions between zooplankton, phytoplankton and their environment. The data is ideally suited for use in a computer model to predict the effects of management actions on the Swan River estuary. This would allow pre-emptive management strategies to be developed and lessen the focus on reactive management.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 200-242). Also available on the World Wide Web.

A dietary survey of male volunteers, both drinkers, and nondrinkers of alcohol, on free choice diets, was conducted in Blacksburg, Virginia in the spring and summer of 1981. The survey was conducted to assess the relationship between the consumption of alcohol and the intake of selected nutrients on both a mean daily basis and on a per kilogram body weight basis. One hundred seventy-one subjects ages 18 through 56 kept food and beverage intake records for five consecutive days, including Saturday and Sunday. The food and beverage records were hand coded and processed by computer for nutrient analysis. Subjects were grouped, according to the amount of alcohol consumed, into nondrinkers, low, moderate or high drinkers. Regression and correlation analysis revealed that there was little difference among the groups of subjects in the effects of alcohol intake on intake of the traditional energy supplying nutrients, protein, fat, and carbohydrate expressed as mean daily intake and expressed on a per kilogram body weight basis. The expression of nutrient intake based on a per kilogram body weight basis made no difference in the significance of results when considering the relationship between the consumption of alcohol and calcium, iron, magnesium, phosphorus, vitamin A, thiamin, riboflavin, niacin, vitamin B6, vitamin B12, and vitamin C. The need for further investigation into the relationship between alcohol consumption and nutrient intake of social drinkers has been documented. / M.S.

Three experiments were conducted to contrast the effect of dissimilar lipid sources on broiler chicken metabolism. In Experiment 1, the nitrogen-corrected apparent metabolizable energy values (AME_n) of soybean oil (SBO) and hydrogenated soybean oil (HSBO) were determined. Trans monoenes, present only in HSBO, comprised 41% of total fatty acids. The AME_n contents of SBO and HSBO were determined to be 8,739 and 7,657 kcal/kg, respectively. The influence of dietary fatty acids on the lipid composition of the intestinal brush border membrane (BBM) was studied in Experiment 2. Beginning at hatch, chickens were provided isocaloric diets, identified as being either a minimal-lipid (1% 18:2n6) basal diet (ML) or one of three diets in which one-sixth of the caloric content of the basal diet was replaced by oils high in either polyunsaturates (HP), saturates (HS), or trans (HT) monoenes. The BBM alkaline phosphatase specific activity was greater in chickens fed HT than in those fed ML, HP, and HS. The BBM concentrations of palmitic, stearic, and oleic acids were not affected by treatment. Less linoleate (P<.06) and linolenate (P<.05) were present in the BBM of chickens receiving HT and HS than in those fed ML and HP. Arachidonate was present in greater concentrations when birds were fed ML, HP, and HS than when fed HT. Trans isomers were present only in the BBM from chickens fed HT. In Experiment 3, the effects of supplemental dietary lipidS on 1) the lipid composition of intestinal tissue and 2) the in vitro absorptive rate of differing dietary nutrients were studied. Diets similar to those in Experiment 2 were offered to broiler chicks from hatch to 28 days of age. Intestinal membrane concentrations of palmitic and oleic acids were not affected by dietary treatment. Chickens receiving the HSBO or the palm oil diet had less intestinal 18:0, 18:2n6, 18:3n3, and 20:4n6 than did those offered SBO or the control diet. In all treatments, linoleate and oleate were absorbed at a faster rate than stearate across all treatments. The in vitro uptake rates of oleate and linoleate were not affected by dietary treatment. Stearate and glucose uptakes were reduced in chickens fed HSBO or palm oil compared to those offered either the control diet or SBO diet. / Ph. D.

The specific dynamic effects of carbohydrate, fat and protein were measured in five adult women. Basal metabolic rates were measured while subjects were in the post-absorptive state. Subjects ingested 5.7 Cal./kg of body weight of the nutrients on different days. Measurements were made at regular time intervals after the meal until the amount of expired air approximated that of the basal state. Samples of expired air were analyzed for oxygen and carbon dioxide. Changes in the respiratory quotient and Cal. per square meter of body surface, with relationship to time of ingestion of each pure compound were studied. There was a general trend for subjects with higher basal energy metabolism to have greater increases in the respiratory quotient after the ingestion of carbohydrate, or fat or protein. An increase in respiratory quotient and beat production was observed following the ingestion of each of three nutrients. There was no definite correlation between the changes in respiratory quotient and variations in heat production after ingestion of carbohydrate, fat and protein by women. Individuals varied in their responses to carbohydrate, fat and protein, but similarities among the individuals in their response to each of these foodstuff was apparent. / Master of Science

Thesis (M.Sc. Biology)--University of Waikato, 2009. / Title from PDF cover (viewed Apr. 22, 2010). Includes bibliographical references (p. 35-47, 104-120)