922 resultados para Dopamine, Ascorbic acid
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Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied, LA and AA independently affect selected plasma FAA in pacu, and suggest that any use of LA in particular as a dietary supplement should take into account an altered plasma FAA profile.
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Background. Iron-deficiency anemia currently is the most frequently occurring nutritional disorder worldwide. Previous Brazilian studies have demonstrated that drinking water fortified with iron and ascorbic acid is an adequate vehicle for improving the iron supply for children frequenting day-care centers. Objective. The objective of this study was to clarify the role of ascorbic acid as a vehicle for improving iron intake in children in day-care centers in Brazil. Methods. A six-month study was conducted on 150 children frequenting six day-care centers divided into two groups of three day-care centers by drawing lots: the iron-C group (3 day-care centers, n = 74), which used water fortified with 10 mg elemental iron and 100 mg ascorbic acid per liter, and the comparison group (3 day-care centers, n = 76), which used water containing only 100 mg ascorbic acid per liter. Anthropometric measurements and determinations of capillary hemoglobin were performed at the beginning of the study and after six months of intervention. The food offered at the day-care centers was also analyzed. Results. The fo od offered at the day-care center was found to be deficient in ascorbic acid, poor in heme iron, and adequate in non-heme iron. Supplementation with fortified drinking water resulted in a decrease in the prevalence of anemia and an increase in mean hemoglobin levels associated with height gain in both groups. Conclusions. Fortification of drinking water with iron has previously demonstrated effectiveness in increasing iron supplies. This simple strategy was confirmed in the present study. The present study also demonstrated that for populations receiving an abundant supply of non-heme iron, it is possible to control anemia in a simple, safe, and inexpensive manner by adding ascorbic acid to drinking water. © 2005, The United Nations University.
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Effects of dietary α-lipoic acid (LA) and ascorbic acid (AA) on the growth, tissue vitamin C and tocopherol (vitamin E) levels, and malondialdehyde levels were examined in the tropical fish pacu, Piaractus mesopotamicus. Pacu juveniles were fed one of four casein-gelatin-based diets for 8 weeks: with 0.05% AA and 0.1% LA (+AA+LA), with AA and without LA (+AA-LA), without AA and with LA (-AA+LA), and without AA and LA (-AA-LA). When the fish received quantities of feed equal to 1.9-2.5% of its body weight, growth was not influenced, regardless of the presence of AA or LA throughout most of the experimental period. Growth was, however, slightly but significantly lower at week 8 in the AA-deficient/LA-supplemented group. An AA-deficient diet caused a highly significant reduction in both total AA and dehydroascorbic acid content in the liver and gill tissues. This reduction of tissue AA concentrations was reversed in a significant manner by LA (antioxidant-sparing effect). The 8-week-long vitamin C deprivation was sufficient to initiate the reduction in tissue ascorbic acid; however, total ascorbate in the liver of fish in the (-)AA/(+)LA group was 127.7±54.3 nmol g-1 tissue, whereas it was 28.6±26.3 nmol g-1 in the (-)AA/(-)LA group, a 4.4-fold difference. This mitigating effect of the addition of the endogenous antioxidant LA to the diet indicates that LA exerts a vitamin C-sparing effect in teleost fish that by far exceeds the phenomena demonstrated in non-scurvy-prone mammals. There was no difference among the different diet groups for vitamin E and malondialdehyde levels in the liver. These results suggest that LA is a potent substance for the prevention of AA deficiency in cultured fishes. The optimal dietary level of LA needs to be determined in the light of the slight reduction in body weight gain after 8 weeks of feeding in the absence of AA. © Springer Science+Business Media, Inc. 2006.
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The objective of this study was to evaluate the effects of adding ascorbic acid to the media for in vitro culture of cattle ovarian fragments and to determine their effects on growth activation and viability of early-stage follicles. The ovarian cortex was divided into small fragments; one fragment was immediately fixed (control) and the other fragments were cultured in minimum essential medium (MEM) supplemented or not with various doses of ascorbic acid. Ovarian tissue was processed for histology, transmission electron microscopy (TEM) and immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA). Compared with control fragments, the percentage of primordial follicles was reduced (p < 0.05) and the percentage of growing follicles had increased (p < 0.05) in cultured cortical fragments, independent of the tested medium or incubation time. Furthermore, compared with control tissue, culture of ovarian cortex for 8 days reduced the percentages of healthy, viable follicles (p < 0.05), but not when cultures were supplemented with 25, 50 or 100 μg/ml of ascorbic acid. Ultrastructural and immunohistochemical analysis of 8 day cultured ovarian cortical fragments, however, showed the integrity and viability of follicles only when fragments were cultured in presence of 50 μg/ml of ascorbic acid. In conclusion, this study demonstrated that addition of ascorbic acid to MEM at a concentration of 50 μg/ml not only stimulates the activation of 8 day in vitro cultured cattle primordial follicles and subsequent growth of activated follicles, but also safeguards the viability of these early-stage follicles. © 2012 Copyright Cambridge University Press.
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This study was aimed to verify if chicks from eggs injected with ascorbic acid and subjected to thermal stress would have higher immunity than chicks from incubation at thermoneutrality without injection of ascorbic acid. The parameters evaluated were temperature on oxygen saturation in hemoglobin, glucose, number of erythrocytes, hematocrit rate and number of hemoglobins of newly hatched male chicks, hatched from eggs injected with ascorbic acid (AA) and subjected to thermal stress during incubation. The experimental design was completely randomized in factorial scheme 5 (application levels of ascorbic acid) x 2 (incubation temperatures). The data were subjected to analysis of variance using the General Linear Model procedure (GLM) of SAS ®. For the parameters (number of erythrocytes, rate of hematrocit and values of hemoglobin), there was significant interaction (p <0.05) between treatments in egg and incubation temperatures. Analyzing the interactions for these parameters, it was observed that the application of 0% ascorbic acid in egg minimized the effect of heat stress when compared with treatment without injection. The application of ascorbic acid levels in eggs incubated under heat stress failed to maximize the immunity of newly hatched chicks. It is assumed that the increased liquid in the amniotic fluid, in those embryos injected with water, favored the lower heat conductance for these embryos, thus helping in their development in relation to immunity. Considering that hemoglobin is related to the transport of gases, these data suggest that increasing the concentration of AA solution inoculated may influence the respiratory rates of eggs.
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This study aimed to verify that chicks from eggs injected with ascorbic acid and subjected to heat stress would have changes in acid-base balance, compared to chicks incubated at thermoneutral without injection of ascorbic acid. The parameters evaluated were blood pressure of carbon dioxide and oxygen, base excess, total carbon dioxide, concentration of sodium, potassium, ionized calcium, bicarbonate and pH of newly hatched male chicks, hatched from eggs injected with acid ascorbic acid (AA) and subjected to heat stress during incubation. The experimental design was completely randomized in factorial scheme 5 (application levels of ascorbic acid) x 2 (incubation temperatures). The data were subjected to analysis of variance using the General Linear Model procedure (GLM) of SAS ®. For the blood pH was observed significant interaction (p <0.05) between treatments with application in eggs and incubation temperatures. For the other parameters were not significant effects (p< 0.05) of AA level and neither temperature of incubation. Analyzing the unfolding of the interaction to pH was observed that chicks from eggs injected with 6% ascorbic acid and subjected to heat stress during incubation had a higher pH value compared with the thermoneutral temperature incubated (p <0.05). Therefore, it is suggested that the incubation of eggs in high temperature (39°C) can alter the metabolic rate of these embryos.
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Mass transfer was evaluated during osmotic dehydration of pineapple in solutions with until four components aiming to investigate the solutes concentration influence on impregnation. In the first step, the experimental trials for optimization of solution concentration were based on 23 factorial design. In the second step, effective diffusion coefficients were determined. Equations representing the influence of the concentration of sucrose, calcium lactate, and ascorbic acid in osmotic solutions on water loss and gains of sucrose, calcium, and vitamin C were found. Results showed that both calcium lactate and sucrose concentration affected calcium and sucrose gain. On the other hand, only vitamin C gain was significantly affected by the ascorbic acid concentration in the studied concentration range. However, when comparing diffusivities in pineapple immersed in sucrose solutions, with and without calcium lactate, with and without ascorbic acid, it was possible to verify that diffusivities of water, sugar, and calcium increased in presence of ascorbic acid in solution. Calcium in solution diminished the water and sucrose diffusivities. High calcium and vitamin C contents were obtained in 1 h immersion in the solutions studied. © 2013 Springer Science+Business Media New York.
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This work has been carried out in order to determine the copper content in sugar cane spirit samples from the south of Minas Gerais, using a carbon paste electrode modified with ascorbic acid and carbon nanotubes using the square wave voltammetry technique. The following parameters were studied: Ed (deposit potencial). Td (deposit time), f (frequency), A (amplitude) and ΔEs (increment scanning). The analytical curve was built in an interval from 0.5 to 12 mg L-1 and a coefficient of linear correlation of 0.997 Three sugar cane spirit samples were analysed, which presented copper content ranging from 0.29 to 1.59 mg L-1.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The present study investigated the osmotic dehydration (OD) of mangoes cv.Palmer, dehydrated in a sucrose solution with added ascorbic acid (AA), aiming toevaluate the influence of the process variables (sucrose concentration, AA concen-tration and time) on vitamin C, water, sugars and total phenolic compound (TPC)contents by way of an analysis of the effects and the variance of the factors. Thesucrose concentration did not affect the vitamin C content, but the AA concentra-tion in the solution and the process time exerted a positive influence on thisresponse. The addition of AA also presented a significant positive effect on theTPC contents because this vitamin interferes with the quantification of the TPC.On discounting the interferences, no losses of phenolic compounds were found.Impregnation with vitamin C during OD was shown to be effective in obtainingminimally processed mangoes with high nutritional value.
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A novel nanostructured composite, azide copper octa (3-aminopropyl)octasilsesquioxane (ASCA) was incorporated into a graphite paste electrode and the electrochemical studies were conducted with cyclic voltammetry. The cyclic voltammogram of the modified graphite paste electrode with ASCA (GPE-ASCA), showed one redox couple with formal potential (E ) = 0.30 V and an irreversible process at 1.1 V (vs Ag/AgCl; NaCl 1.0 mol L-1 ; v = 20 mV s-1 ). The redox couple with (E ) = 0.30V presents an electrocatalytic response for determination of ascorbic acid. The modified electrode gives a linear range from 1.010-4 – 1.010-3 mol L-1 (r = 0.998) for the determination of ascorbic acid with detection limit of 6.910-5 mol L-1 and standard deviation of 2.3% for n = 3 . The amperometric sensitivity was 122.1 mA/mol L-1 for ascorbic acid. The application this electrode was tested and ascorbic acid in three commercial pharmaceutical product (Cebion, Cewin and Redoxon) have been determined.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This study tested the effect of Sigma antioxidant supplement®, α-tocopherol (vitamin E) and L-ascorbic acid (vitamin C) in the culture medium of bovine embryos. In experiment 1, in vitro produced bovine zygotes were cultured in Human Tubal Fluid (HTF): Eagle’s Basic Medium (BME) with: Group 1 – 50 µm vitamin C; Group 2 – 200 µm vitamin E; Group 3 – 25 µm vitamin C and 100 µm vitamin E; Group 4 – 1 µl/ml Sigma antioxidant supplement®; and the Control group – HTF:BME only. In experiment 2, embryos were cultured in high or low oxygen tension with HTF:BME + Sigma antioxidant supplement® or in HTF:BME alone (Control). The data were analyzed using ANOVA followed by Tukey’s test. The results of experiment 1 showed a negative effect (P < 0.05) of vitamin E on blastocyst production in Group 2 (19.7 ± 0.1%). This effect was reduced in Group 3 by the addition of vitamin C (26.1 ± 0.2%). The use of vitamin C alone (34.9 ± 0.3%) or the Sigma antioxidant supplement® (33.3 ± 0.7%) did not increase (P > 0.05) the number of blastocysts produced compared with the control group (30.1 ± 0.5%). During experiment 2, there was no effect (P > 0.05) from the culture medium or the O2 concentrations used, indicating that the reduction of the O2 concentration did not improve blastocyst production.
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The objective of this work was (1) to develop a dehydrated pepper with 45% humidity, determining the drying curves for pepper, with and without osmotic pre-treatment and (2) to evaluate the influence of both drying and osmotic treatment on the content ascorbic acid (vitamin C) in fresh pepper and pepper with 45% humidity. The experiments were carried out using the peppers cut in half, with and without osmotic pre-treatment, followed by drying in an oven at 70 degrees C. The results showed that the osmotic pretreatment did not influence the retention of ascorbic acid during the drying of pepper. The sensory analysis regarding the color, flavor, and texture attributes revealed that there was no difference in the acceptability.