Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

No description available.

Four studies were conducted to evaluate the effects of supplemental cooling and niacin on heat stress (HS) responses in vivo and in vitro in lactating dairy cows. For experiment one, lactating dairy cows were fed four levels of dietary niacin, NIASHURE® (0,4,8,12 g/d) for 21 d. Heat stress decreased niacin levels in whole blood, red blood cells and plasma as compared to thermoneutral. Water intake, plasma and milk niacin concentrations increased linearly with increasing dietary niacin in HS cattle. In thermoneutral, but not HS cows, niacin increased skin temperature compared to controls suggesting niacin increased skin blood flow and sensible heat loss. In experiment 2, lactating cows were used to evaluate the impact of feed-line soaking (FLS) combined with niacin supplementation. In evaporative cooled barns, FLS reduced body temperatures; however the addition of niacin did not improve heat status of these cows. For experiment 3, 200 lactating dairy cows were used to determine the effects of conductively cooled bedding (CC) compared to feed-line soaking with fans (FLSF). Conductively cooled bedding can reduce skin and vaginal temperatures in cows after nighttime rest. However, FLSF were more effective in decreasing body temperature, as cows had lower heat parameter indices, higher milk yield and longer rest time. For experiment 4, three cell types were used to evaluate niacin in vitro. Niacin induced heat shock proteins (HSP) that protected cells during HS in transformed bovine mammary epithelial cells but not in primary bovine mammary epithelial cells (BMEC) or bovine endometrial cells (BEND). Effect of niacin on HSP may depend on enzymes involved in DNA-binding activity of heat shock factor 1. These results suggest that niacin may be involved in whole body metabolism during heat stress and is cell dependent. We did not find dietary niacin to be commercially efficacious in treating HS in cows. Further research is warranted to improve efficacy of CC and FLSF under high temperature humidity index conditions.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 263-272). Also available on the Internet.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 263-272). Also available on the Internet.

Orientadores: Eliana Cotta de Faria, Andrei Carvalho Sposito / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-25T05:11:23Z (GMT). No. of bitstreams: 1 Vendrame_Felipe_M.pdf: 1091840 bytes, checksum: 4ae9b0626a5c1d06cdf37066842a24fc (MD5) Previous issue date: 2014 / Resumo: Baixas concentrações plasmáticas da lipoproteína de alta densidade (HDL-C) constituem um dos fatores de risco para o desenvolvimento da doença cardiovascular aterosclerótica, a principal causa de morte nos países desenvolvidos e emergentes. A niacina é conhecida por ser o principal fármaco a aumentar as concentrações de HDL-C. A concentração plasmática reduzida das lipoproteínas de alta densidade está associada à vulnerabilidade ao estresse oxidativo e a propensão à disfunção endotelial. A niacina através da ativação de seu receptor específico acoplado à proteína G (GPR109A) promove efeitos anti-inflamatórios e antioxidantes. Com base nestas informações, este estudo investigou o efeito de curto prazo da niacina e da niacina associada ao laropipranto sobre a função endotelial, parâmetros séricos bioquímicos e físico-químicos em indivíduos hipoalfalipoproteinêmicos. O estudo foi realizado em 18 indivíduos assintomáticos, de ambos os gêneros com idade entre 20 e 60 anos apresentando concentrações plasmáticas de HDL-C abaixo de 40 mg/dL. Os indivíduos foram tratados com niacina de liberação prolongada 1g/dia (NLE, Metri, Libbs Farmacêutica, São Paulo, Brasil) e niacina associada ao laropipranto 1g/20mg (NLE/LRPT, Cordaptive, Merck, São Paulo, Brasil), em um estudo crossover e a sequência de tratamentos foi realizada de forma aleatória. As amostras de plasma e a dilatação fluxo mediada da artéria braquial (FMD) foram obtidas no início do estudo, no 7º dia do tratamento 1, no 7º dia após washout e no 7 º dia do tratamento 2. Após terapias com NLE e NLE/LRPT as concentrações de triglicérides diminuíram 4,0% e 3,0% (p <0,05) e o tamanho da HDL 5,8% e 6,2%, (p <0,05) além de aumentarem a glicose 5,0 e 8,0 % (p <0,02) e a bilirrubina direta 62% e 50% (p <0,04); também foi observado aumento médio do FMD de 4,5% e 4,1% nos grupos NLE e NLE/LRPT, respectivamente. Não houve alteração de HDL-C e na atividade da proteína de transferência de colesteril éster (CETP) após ambos os tratamentos. Todas estas modificações foram revertidas após o período de washout. Na análise intergrupos, não houve diferenças em relação à variação de HDL-C, triglicérides, proteína C reativa, bilirrubina direta e FMD. Os resultados revelam que a terapia de niacina de curto prazo pode melhorar a função endotelial em indivíduos com baixas concentrações de HDL-C. A adição do antagonista de PGD2 (laropipranto) não influenciou o efeito da niacina sobre a função endotelial / Abstract: Low plasma levels of high-density lipoprotein-cholesterol (HDL-C) are one of the risk factors involved in the development of atherosclerotic cardiovascular disease, the main cause of death in developed and emerging countries. Niacin is known as the main drug used to increase HDL-C levels. Reduced concentrations of high density lipoproteins are associated to oxidative stress vulnerability and tendency to endothelial dysfunction. Niacin, through the activation of its specific receptor coupled to G protein (GPR109A) promotes anti-inflammatory and antioxidant effects. Therefore, this study investigated the short-term effect of niacin and niacin associated to laropiprant on endothelial function, biochemical and physical-chemical serum parameters, in hypoalphalipoproteinemic subjects. The study was carried out in 18 asymptomatic subjects, male and female, aged between 20 and 60 years, with HDL-C plasma concentrations below 40 mg/dL. Subjects were treated with extended-release niacin 1g/day (NLE, Metri, Libbs Pharmaceutics, Sao Paulo, Brazil) and niacin associated to laropiprant 1g/20mg (NLE/LRPT, Cordaptive, Merck, Sao Paulo, Brazil), in a crossover study. The sequence of treatments was randomly determined. Plasma samples and flow-mediated dilatation of the brachial artery (FMD) were obtained in the beginning of the study, on the 7th day of treatment 1, on the 7th after washout and on the 7th day of treatment 2. After therapies with NLE and NLE/LRPT respectively, triglycerides (TG) concentrations decreased 4,0% and 3,0% (p <0,05) and HDL size 5,8% and 6,2%, (p <0,05); besides, glucose increased 5,0 and 8,0 % (p <0,02) and direct bilirubin 62% and 50% (p <0,04). The average increase of FMD was 4,5% and 4,1% on NLE and NLE/LRPT groups, respectively. No changes in HDL-C and the activity of cholesteryl ester transfer protein (CETP) after both treatments were observed. All these changes were reversed after the washout period. In intergroup analysis, no differences were found regarding variations in HDL-C, triglycerides, C reactive protein (CRP), direct bilirubin and FMD. These results suggest that short-term niacin therapy may improve endothelial function in subjects with low HDL-C concentrations. The addition of the PGD2 antagonist (laropiprant) did not influence niacin¿s effect on endothelial function / Mestrado / Clinica Medica / Mestre em Ciências

Niacin som upptäcktes för 70 år sedan är en substans som än i dag studeras mycket kring. Men fortfarande är man inte överens om niacin verkligen har en signifikant effekt på kardiovaskulära sjukdomar. Verkningsmekanismen för niacin är ännu oklar, men forskning pekar på att hämmad syntes av triglycerider resulterar i en minskad LDL-koncentration. HDL-ökningen tros bero på en hämmad nedbrytning av HDL-partiklar, och därmed blir en större mängd HDL kvar i blodet. Nuvarande lipidbehandling består först och främst av en balanserad kost och ökad fysisk aktivitet. Vid otillräcklig effekt sätts läkemedelsbehandling in, som består av statiner, resiner, fibrater och hämmare av kolesterolupptag i tarmen. Syftet med detta arbete är att studera om niacin, både som monoterapi och i kombination med andra lipidsänkande preparat, har en påverkan på blodlipidvärdena HDL, LDL och triglycerider, hos människor. Genom systematisk litteratursökning har artiklar samlats in för att kunna sammanställa resultaten. Alla tio studierna som inkluderades kom fram till att niacin, antingen i kombination med andra lipidsänkande preparat eller som monoterapi, har en signifikant effekt på lipoproteinerna. Resultaten visade en LDL-sänkning upp till 58,5% (i kombination), den högsta HDL-ökning var 50% (monoterapi) och högsta triglycerid-sänkningen var 51,7% (i kombination). Dock är niacins effekt på LDL och triglycerider likartad eller sämre än dagens lipidsänkande preparat. Niacin har däremot en större effekt när det kommer till HDL-ökningen. Därför bör det göras flera och större studier gällande niacins effekt på HDL. Om studierna visar positiva resultat bör det övervägas för användning hos patienter med låg HDL. Dock orsakar biverkningarna en sämre följsamhet, och eventuella analoger till niacin bör utvecklas, detta för att inte gå miste om en eventuellt potent HDL-ökande behandling. Slutsatsen för detta arbete är att i människa har niacin en signifikant effekt på lipoproteinerna LDL och HDL samt lipiden triglycerider. Behandling med niacin leder till en sänkning av LDL och triglycerider samt en markant ökning av HDL.

OBJECTIVE: Niacin, activating G-protein coupled receptor (GPR) 109A, stimulates release of vasodilatory prostaglandins (PGs) such as PGE2 which can elicit niacin-associated flushing side effects. Poly-lactic-coglycolic acid (PLGA) and poly-lactic acid (PLA) are used in nanoparticle (NP) drug delivery to reduce adverse effects and modulate drug release. Our study evaluated the in vitro effects of niacin-loaded PLGA or PLA-NPs on PGE2 expression in whole human blood as a model for niacin-induced flushing. MATERIALS AND METHODS: NPs were formulated using a solvent evaporation process and characterized by size, polydispersity, zeta potential, drug entrapment, morphology, and drug release. NP in vitro effects on PGE2 release were measured via ELISA analysis. RESULTS: PLGA-NPs demonstrated the lowest NP size (66.7 ± 0.21 nm) with the highest zeta potential and percent drug entrapment (42.00 ± 1.62 mV and 69.09 ± 0.29%, respectively) when compared to PLA-NPs (130.4 ± 0.66 nm, 27.96 ± 0.18 mV, 69.63 ± 0.03 %, respectively). In vitro release studies showed that PLGA-NPs underwent significant reductions in cumulative drug release when compared to PLA-NPs (p < 0.05). Furthermore, when compared to plain niacin, PLGA-NPs significantly reduced in vitro PGE2 release (p < 0.05). CONCLUSIONS: These results support the use of PLGA-NPs as a novel method of delivery for reducing niacin-associated flushing.

Alfalfa has long been recognized as an outstanding hay plant in term. of both yield and feeding value. It is high in digestible protein, minerals, and vitamins. Because of its long life it can be economically produced. It is of exceptional value in maintaining soil fertility by helping to control erosion, by improving the physical condition of the soil, and by accumulating large amount of nitrogen.

The purpose of this study is to determine the nicotinic acid values of the food consumed and the urinary and fecal excretions of young college women on self-selected diets.