Thesis (Ph. D.)--Cornell University, 1989. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Toledo, 2008. / Typescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy degree in Chemistry." Includes bibliographical references (leaves 32-37, 74-75, 112-114, 155-157, 187-188, 193).

Made available in DSpace on 2014-06-11T19:27:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-30Bitstream added on 2014-06-13T20:16:55Z : No. of bitstreams: 1 fernandesjunior_ac_me_botfmvz.pdf: 185727 bytes, checksum: 7f9166561ac8913b0a0f5eff1f746276 (MD5) / Universidade Estadual Paulista (UNESP) / Essa pesquisa teve por objetivo avaliar o desempenho produtivo da tilápia do Nilo (Oreochromis niloticus) arraçoada com níveis crescentes de colina nas dietas. O período experimental foi de 109 dias. Foram utilizados 192 alevinos com peso médio inicial de 4,0 gramas, distribuídos em 32 tanques-rede de 200 L, numa densidade de seis peixes por tanque rede, sendo os tanques-rede alojados em aquários de 1000 L. O conjunto de aquários era dotado de sistema de filtragem de água por meio de biofiltro e sistema de aquecimento, sendo a temperatura mantida a 25,3 ± 0,2ºC. As rações foram formuladas de modo a apresentar 28,0% de proteína digestível e 3100,0 kcal ED/kg de dieta com mesma concentração de aminoácidos. O delineamento experimental foi inteiramente casualizado com oito tratamentos e quatro repetições. As rações foram suplementadas com colina (cloreto de colina 60,0%) de modo a apresentarem 100,0; 200,0; 400,0; 600,0; 800,0; 1000,0 e 1200,0 mg de colina por quilograma de ração, além de uma ração isenta de suplementação. Não foram observadas diferenças estatísticas para ganho de peso, taxa de sobrevivência e conversão alimentar aparente, porcentagem de extrato etéreo do filé e concentração de lipídeos no plasma. No entantohouve diferença estatística para o índice hepatossomático e porcentagem de extrato etéreo do fígado, sendo que 800,0 mg de colina/kg de dieta determinou maior ação lipotrófica. O oposto foi observado nos peixes do tratamento isento de suplementação. Concluiu-se que os diferentes níveis de colina não melhoram o desempenho produtivo dos peixes, pois a dieta basal supostamente supriu a exigência do peixe para colina, entretanto, a suplementação favoreceu a melhora no estado do fígado. / The aim of this study was to evaluate the performance of Nile tilapia (Oreochromis niloticus) fed diets supplemented with increasing levels of choline. The experimental period was 109 days. One hundred and ninety two (initial weight 4.0 g) fingerlings were distributed in 32 net cages (200L), with a density of six fish per cage. These cages were allocated in 1000L aquariums connected to a bio-filter system and heater controlled temperature through thermostat (25.3 ± 0.2ºC). Feeds were formulated to contain 28% of digestible protein and 3100 kcal DE/kg with the same concentration of amino acids per treatment organized in totally random experimental design with eight treatments and four replicates. The feeds were supplemented with choline chloride (60%) presenting 100, 200, 400, 600, 800, 1000, 1200 mg of chlorine per kg of feed and one treatment with no supplementation. It was not observed any significant differences in performance, survival and apparent feed conversion, fillet ether extract and plasma lipids concentration among the treatments. However, there was a significant difference in the hepatosomatic index and liver ether extract percentage, showing that 800 mg of choline/kg determined a better lipotrofic action and the opposite was observed in fish fed diet with no choline supplementation. It was concluded that different levels of choline did not improve performance supposedly due to the amount of choline...

A Doença Hepática Gordurosa Não Alcoólica (DHGNA) é uma condição clínicopatológica comum, caracterizada por depósito de lipídeos no hepatócito do parênquima hepático. A esteatose hepática (EH) é um dos componentes da DHGNA e caracteriza-se pela presença de vacúolos de lipídeos, principalmente triacilgliceróis (triglicerídeos), dentro dos hepatócitos. Alterações na oxidação das gorduras no fígado ou redução na exportação de lipoproteínas de muito baixa densidade (VLDL) a partir do órgão são os principais mecanismos etiopatogênicos envolvidos com a EH. A patogênese da DHGNA é multifatorial e diversos fatores ou condições têm sido relacionados à predisposição para o seu desenvolvimento. Atualmente, diferentes tratamentos farmacológicos para DHGNA estão sendo propostos, mas ainda não há nenhum estudo comprobatório da sua eficácia. Objetiva-se avaliar os efeitos da suplementação da colina e do frutooligossacarídeo (FOS) na dieta de ratos Wistar, no modelo de esteatose hepática, induzido por dieta hiperglicídica. Foram utilizados 46 ratos machos, da raça Wistar adultos com peso variando entre 250 - 320 g, vindos do Biotério Central do Campus da USP Ribeirão Preto. Do lote inicial de animais foram distribuídos de forma aleatória nos diferentes grupos de estudo de I a IV, dependendo da indução ou não da esteatose. Considerou-se fase I o período correspondente a indução de esteatose e fase II quando se submeteu os animais a suplementação com nutrientes (Grupos III e IV), ou quando os animais receberam dieta padrão pós fase I (Grupo II) . Os animais do Grupo I (controle) receberam ração padrão do biotério que foi igual para todos os animais, sendo separado um lote da mesma ração para todo o experimento. Foi analisado as seguintes variáveis: Ingestão alimentar semanal, evolução do peso dos animais, nitrogênio urinário, amônia urinária, colesterol total e triacilgliceróis séricos, peso úmido de fígado e coração, nitrogênio e gordura tecidual, dosagem de vitamina E, malondialdeído (MDA) e glutationa no tecido hepático e análise histopatológica. Observamos que nenhum dos nutrientes empregados (colina e FOS) foi eficaz na redução da quantidade de gordura do fígado pela análise histológica. Nenhum dos nutrientes adicionados foi capaz de proteger o fígado da ação dos radicais livres, já que o MDA, um marcador indireto da geração do estresse oxidativo, manteve-se com valores elevados mesmo na fase de tratamento. Ocorreu diminuição dos níveis de triacilgliceróis em todos os grupos submetidos à indução de esteatose, do início ao final do experimento. O frutooligossacarídeo foi capaz de reduzir os níveis de colesterol sérico, em relação aos seus níveis basais, quando suplementado após indução de esteatose. / Non-alcoholic fatty liver disease (NAFLD) is a common clinical pathological condition characterized by fat accumulation in the the hepatic parenchyma hepatocyte. Liver steatosis (HS) is one of the components of NAFLD and is characterized by the presence of lipids vacuoles, mainly triacylglycerol, within the hepatocites. Alterations in fat oxidation in the liver or very low density proteins lipoproteins tranport from the organ are the main etiopatogenic mechanisms involved in HS. NAFLD patogeny is multifactor, thus several factors have been associated the propensity to develop it. Presently, many drug treatments for NAFLD are being suggested, however, there have been no studies that prove their efficacy so far. The aim of this study was to assess the effects of choline and fructooligosaccharide (FOS) suplementation in Wistar rats with HS induced by high glicid diet. Forty six adult male Wistar rats weighing between 250g and 320g from the USP (Ribeirão Preto-USP) central vivarium were used. They were divided randomly into different study groups from I to IV depending on whether steatosis would be induced or not. Phase I of the study was the period corresponding to steatosis induction and phase II was when the animals received nutrient suplementation (Groups III and IV) or when they received standard diet (Group II). Group I animals (control) received the usual vivarium food, which was the same for all of them. A certain amount of that same food was kept aside for the duration of the experiment. The following variables were analyzed: weekly food intake, weight gain, urine ammonia, urine nitrogen, total cholesterol and serum triacylglycerol, liver and heart humid weight, nitrogen and tissue fat, vitamin E, malondialdehyde (MDA) and glutathione content in the liver tissue and hitopathological analysis. As observed, neither of the nutrients (choline and FOS) was efficient in reducing the amount of fat in the liver. Neither of the nutrients added was able to protec the liver from free radicals, once the MDA, a indirect marker for oxidative stress generation, showed high levels even during the treatment phase. There was a reduction in triacylglycerol levels in all steatosis induced groups, from the beginning to the end of the experiment. Fructooligosaccharide was able to reduce the levels of serum cholesterol, in relation to its basal levels, when suplemented after steatosis induction.

The substance choline, one of the quaternary nitrogen bases, has been the subject of a number of reviews and investigations. It has been described as a cholinergic agent, an inotropic agent, a vitamin, and perhaps in other ways. In spite of the interest shown in its action and uses, there is as yet very little information available as to the mechanism by which it is absorbed by the intestinal mucosa. The studies referred to thus far leave the field open for additional investigation. No mention was found in the literature of studies on selective areas of absorption of choline in the small intestine, or whether enzyme inhibitors might produce an effect on rate of absorption. In view of the possibility that active transport, and thus enzyme activity, might be involved in choline absorption, it is conceivable that rate of choline absorption might be altered by such enzyme inhibitors as phlorizin and 2, 4-dinitrophenol. Selective areas of choline absorption, and the effects of several enzyme inhibitors were, then, selected as the areas for investigation in the study described here.

Alzheimer’s Disease is a growing public health problem, with the number of Americans suffering from the disease projected to more than double from 5.8 million today to 13.8 million in 2050. While there is still no cure for Alzheimer’s Disease, a preventative strategy may mitigate its cost to society in the future. Previous studies have shown an ameliorative effect of perinatal choline supplementation on amyloidosis in the hippocampus of APP.PS1 mice. In this study, we test the effects of perinatal choline supplementation on the APP.NLGF strain of mice – which uses a gene knock-in strategy to avoid the non-physiologic overexpression of amyloid precursor protein and better recapitulate the disease in humans. When compared to APP.NLGF mice raised on a control diet, the perinatal choline supplemented APP.NLGF mice exhibited: i) an amelioration of learning and memory deficits in 9- and 12-months old mice as measured by contextual fear conditioning, ii) reduced amyloidosis in the cortex of 9- and 12-months old mice, and iii) an age- and brain region-dependent response to perinatal choline supplementation. These results suggest that increasing the dietary intake of choline during pregnancy may protect the offspring from AD-associated cognitive decline and amyloidosis.

The environmental neurotoxin trimethyltin (TMT) destroys parts of the hippocampal formation as well as the entorhinal cortex but leaves the septal cholinergic projection to the hippocampus and dentate gyrus intact. In this study we measured choline acetyltransferase (ChAT) activity in micropunch samples of the dentate gyrus, the CA1 region of Ammon's horn, and the caudate-putamen as a measure of density of cholinergic innervation in control rats and rats exposed to 7 mg/kg TMT by means of gastric intubation. Three months after the rats were exposed to a single dose of TMT both the dentate gyrus and CA1 demonstrated significantly higher ChAT activity in TMT-exposed rats than in control rats. No differences were found between groups for the caudate-putamen samples. These results support the hypothesis that exposure to TMT causes reactive synaptogenesis in the cholinergic septohippocampal system.

We hypothesized that estradiol (E2) serves as a neurotrophomodulatory substance for basal forebrain cholinergic neurons thought to be involved in learning and memory. Learning/memory was assessed using the two-way active avoidance paradigm and the Morris water task. Female Sprague-Dawley rats were either ovariectomized (OVX) or OVX for 3 weeks, followed by s.c. implantation of a Silastic pellet containing 17-ß E2 (E2 pellet), resulting in a replacement of E2 to physiological levels. Ovary-intact (INTACT) animals served as our positive control. Active avoidance behavior and choline acetyltransferase (ChAT) activity in the frontal cortex and hippocampus were assessed at 5 and 28 weeks postovariectomy while performance on the Morris water task and high-affinity choline uptake (HACU) were measured only at the 5-week time point. At the 5-week time point, E2 replacement caused a significant elevation in the level of active avoidance performance relative to OVX animals. At the 28-week time point, OVX animals demonstrated a significantly lower number of avoidances relative to controls (61%) whereas E2-pellet animals not only demonstrated superior performance relative to OVX animals but also showed an accelerated rate of learning. Morris water task performance, on the other hand, was not significantly affected by estrogenic milieu despite a trend towards better performance in the E2-pellet group. Neurochemical analyses revealed that 5 weeks of ovariectomy was sufficient to reduce HACU in both the frontal cortex and hippocampus by 24 and 34%, respectively, while E2 replacement was successful in elevating HACU relative to OVX animals in both regions. ChAT activity was decreased in the hippocampus but not the frontal cortex of 5-week OVX animals. E2 replacement resulted in a reversal of this effect. At the 28-week time period, an unexpected decrease in ChAT activity was observed across all treatment groups. Interestingly, E2-pellet animals demonstrated the least severe decline in ChAT. This phenomenon was most evident in the frontal cortex where ChAT decreased by 61 and 56% in INTACT and OVX animals, respectively, whereas the decline in E2-pellet animals was only 16% over the same time period, suggesting a previously unreported cytoprotective effect of E2. Taken together, these findings demonstrate important effects of estrogens on cholinergic neurons and support the potential use of estrogen therapy in treatment of dementias in postmenopausal women.

Obesity is linked to nonalcoholic steatohepatitis. Peroxisome proliferator-activated receptor-a (PPARa) regulates lipid metabolism. Cytochrome P-450 2A5 (CYP2A5) is a potential antioxidant and CYP2A5 induction by ethanol is CYP2E1 dependent. High-fat diet (HFD)-induced obesity and steatosis are more severe in CYP2A5 knockout (cyp2a5 -/- ) mice than in wild-type mice although PPARa is elevated in cyp2a5 -/- mice. To examine why the upregulated PPARa failed to prevent the enhanced steatosis in cyp2a5 -/- mice, we abrogate the upregulated PPARa in cyp2a5 -/- mice by cross-breeding cyp2a5 -/- mice with PPARa knockout (ppara-/- ) mice to create ppara-/- /cyp2a5 -/- mice. The ppara-/- /cyp2a5 -/- mice, ppara-/- mice, and cyp2a5 -/- mice were fed HFD to induce steatosis. After HFD feeding, more severe steatosis was developed in ppara-/- /cyp2a5 -/- mice than in ppara-/- mice and cyp2a5 -/- mice. The ppara-/- /cyp2a5 -/- mice and ppara-/- mice exhibited comparable and impaired lipid metabolism. Elevated serum alanine transaminase and liver interleukin-1β, liver inflammatory cell infiltration, and foci of hepatocellular ballooning were observed in ppara-/- /cyp2a5 -/- mice but not in ppara-/- mice and cyp2a5 -/- mice. In ppara-/- /cyp2a5 -/- mice, although redox-sensitive transcription factor nuclear factor erythroid 2-related factor 2 and its target antioxidant genes were upregulated as a compensation, thioredoxin was suppressed, and phosphorylation of JNK and formation of nitrotyrosine adduct were increased. Liver glutathione was decreased, and lipid peroxidation was increased. Interestingly, inflammation and fibrosis were all observed within the clusters of lipid droplets, and these lipid droplet clusters were all located inside the area with CYP2E1-positive staining. These results suggest that HFD-induced fibrosis in ppara-/- /cyp2a5 -/- mice is associated with steatosis, and CYP2A5 interacts with PPARa to participate in regulating steatohepatitis-associated fibrosis.

No description available.