910 resultados para Total vitamin C
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To evaluate the reproductive performance and the development of their offspring on rat pregnancy. Wistar pregnant rats were gavaged with 0 mg/kg wb/day (control group, n = 20) and 166.5 mg/kg/day of a mixture of vitamin C, hesperidin and piperidol (experimental group, n = 20) during the organogenic period (from day 5 to 14 of pregnancy; positive vaginal smear = day 0). The female rats were killed on day 21 of pregnancy. The number of implantations, resorptions (dead embryos), and live/dead fetuses were counted for the analysis of the postimplantation loss rates. There was neither alteration in maternal reproductive performance, but it was verified an increase of the number of fetuses presenting dilated urether, hydronephrosis, and reduced ossification of skull due to the treatment of female rats with a mixture of vitamin C, hesperidin and piperidol, these abnormalities were considered transitory and may not interfere on offspring development. It was not verified other type of major malformation neither the appearance of fetuses presenting atrophy of upper limbs that it could be associated to use of this drug.
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AIM: Late tooth replantation is a worthy procedure, especially in growing patients, being the best option for tooth avulsion. This study evaluated the effects of root surface treatment with 2% acidulated phosphate sodium fluoride and effervescent vitamin C (Redoxon) in late replantation. METHODS: Twenty rat teeth (Rattus norvegicus, albinus, Wistar) were extracted and left on a table for 6 h. Then, the dental papilla and enamel organ were sectioned and the pulp was removed through the apex. After removal of the periodontal ligament with a blade, the animals were divided into 2 groups: Group I teeth were immersed in 2% acidulated phosphate sodium fluoride solution for 10 min and obturated with Ca(OH)(2) paste. Group II teeth were immersed in effervescent vitamin C solution (Redoxon 2 g) for 10 min and obturated as for Group I. After these procedures, teeth were replanted and animals were killed after 60 days. RESULTS: The study revealed a larger amount of replacement resorption in Group I and larger amount of ankylosis in Group II, with statistically significant difference and absence of inflammatory resorption. CONCLUSION: The substances used for root surface treatment were unable to prevent replacement resorption and ankylosis, which are expected when the periodontal ligament has been lost.
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A vitamina C é essencial para dietas de peixe porque muitas espécies não conseguem sintetizá-la. Esta vitamina é necessária par a formação de cartilagem e matriz óssea. Além disso, age como antioxidante e melhora as resposta do sistema imunológico. O presente trabalho investigou os efeitos da suplementação de vitamina C em dietas para alevinos de pintado (Pseudoplatystoma corruscans) pela incidência de deformidades na estrutura óssea e cartilaginosa. O ascorbil polifosfato (AP) foi utilizado como fonte de vitamina C em dietas para alevinos de pintado durante o período de três meses. Seis dietas foram formuladas: uma dieta controle (0 mg de vitamina C / kg) e cinco dietas 500, 1.000, 1.500, 2.000 e 2.500 mg de AP / kg. Os peixes alimentados sem suplementação de vitamina C apresentaram deformidades óssea na cabeça e mandíbula e fragilidade de nadadeiras. Assim, a dieta de 500 mg de AP/kg foi suficiente para prevenir a ocorrência de deformidades, e a ausência desta vitamina prejudica o desenvolvimento ósseo de juvenis de pintados.
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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 tissue changes that occur in Chagas disease are related to the degree of oxidative stress and antioxidant capacity of affected tissue. Studies with vitamin C supplementation did not develop oxidative damage caused by Chagas disease in the host, but other studies cite the use of peroxiredoxins ascorbate - dependent on T. cruzi to offer protection against immune reaction. Based on these propositions, thirty "Swiss" mice were infected with T. cruzi QM1 strain and treated with two different vitamin C doses in order to study the parasitemia evolution, histopathological changes and lipid peroxidation biomarkers during the acute phase of Chagas disease. The results showed that the parasite clearance was greater in animals fed with vitamin C overdose. There were no significant differences regarding the biomarkers of lipid peroxidation and inflammatory process or the increase of myocardium in animals treated with the recommended dosage. The largest amount of parasite growth towards the end of the acute phase suggests the benefit of high doses of vitamin C for trypomastigotes. The supplementation doesn't influence the production of free radicals or the number of amastigote nests in the acute phase of Chagas disease.
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Background: Bariatric surgery influences the intake and absorption of nutrients. The serum concentrations of vitamin C, myeloperoxidase (MPO) and oral clinical manifestations were examined in patients two years after Roux-en-Y gastric bypass (RYGB). Methods: Clinical prospective-study with control-group (CG; n = 26), assessed only once, and the bariatric-group (BG; n = 26), assessed in the basal period and at 12 and 24 months after surgery. The mean ages in the CG and BG were 37.8 +/- 1.51 and 39.6 +/- 1.93 years, respectively, and their body mass indices were 22.07 +/- 0.29 and 45.62 +/- 1.46 kg/m2, respectively. Results: At 12 months after surgery, increased episodes of vomiting (P < .001) and dental hypersensitivity (P=.012) were observed, with a reduction in the saliva buffering capacity of 21.3 2.9% (P=.004). At 24 months after RYGB, we detected a significant reduction in serum vitamin C (32.9 +/- 5.3%, P < .001) and MPO values were higher than in the basal period (P = .032). With regard to oral hygiene habits, 92.3% of patients reported frequent tooth brushing and 96.1% used fluoride, which were similar across the two years. However, dental hypersensitivity (P = .048) was significantly increased than baseline. Conclusions: The results demonstrated that vitamin C deficiency and increased vomiting after RYGB for morbid obesity may contribute to increased periodontal disease. The fact it is impossible to determine which factors (diet, poor compliance with supplementation, vomiting, poor oral hygiene) contributed to the dental problems in these patients is a shortcoming of the report. (Nutr Clin Pract. 2012; 27: 114-121)
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Abstract Aim Oxidative stress has been implicated in the pathogenesis of Nonalcoholic Fatty Liver Disease (NAFLD). Vitamin C and vitamin E are known to react with reactive oxygen species (ROS) blocking the propagation of radical reactions in a wide range of oxidative stress situations. The potential therapeutic efficacy of antioxidants in NAFLD is unknown. The aim of this study was to evaluate the role of antioxidant drugs (vitamin C or vitamin E) in its prevention. Methods Fatty liver disease was induced in Wistar rats by choline-deficient diet for four weeks. The rats were randomly assigned to receive vitamin E (n = 6) – (200 mg/day), vitamin C (n = 6) (30 mg/Kg/day) or vehicle orally. Results In the vehicle and vitamin E-treated rats, there were moderate macro and microvesicular fatty changes in periportal area without inflammatory infiltrate or fibrosis. Scharlach stain that used for a more precise identification of fatty change was strong positive. With vitamin C, there was marked decrease in histological alterations. Essentially, there was no liver steatosis, only hepatocellular ballooning. Scharlach stain was negative. The lucigenin-enhanced luminescence was reduced with vitamin C (1080 ± 330 cpm/mg/minx103) as compared to those Vitamin E and control (2247 ± 790; 2020 ± 407 cpm/mg/minx103, respectively) (p < 0.05). Serum levels of aminotransferases were unaltered by vitamin C or vitamin E. Conclusions 1) Vitamin C reduced oxidative stress and markedly inhibited the development of experimental liver steatosis induced by choline-deficient diet ; 2)Vitamin E neither prevented the development of fatty liver nor reduced the oxidative stress in this model.
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The tissue changes that occur in Chagas disease are related to the degree of oxidative stress and antioxidant capacity of affected tissue. Studies with vitamin C supplementation did not develop oxidative damage caused by Chagas disease in the host, but other studies cite the use of peroxiredoxins ascorbate - dependent on T. cruzi to offer protection against immune reaction. Based on these propositions, thirty "Swiss" mice were infected with T. cruzi QM1 strain and treated with two different vitamin C doses in order to study the parasitemia evolution, histopathological changes and lipid peroxidation biomarkers during the acute phase of Chagas disease. The results showed that the parasite clearance was greater in animals fed with vitamin C overdose. There were no significant differences regarding the biomarkers of lipid peroxidation and inflammatory process or the increase of myocardium in animals treated with the recommended dosage. The largest amount of parasite growth towards the end of the acute phase suggests the benefit of high doses of vitamin C for trypomastigotes. The supplementation doesn't influence the production of free radicals or the number of amastigote nests in the acute phase of Chagas disease.
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Vitamin C (ascorbic acid) is required for the synthesis of collagen, carnitine, catecholamine and the neurotransmitter norepinephrine. Vitamin C also plays an important role in protection against oxidative stress. Transporters for vitamin C and its oxidized form dehydroascorbate (DHA) are crucial to keep vitamin concentrations optimal in the body. The human SLC23 family consists of the Na(+)-dependent vitamin C transporters SVCT1 (SLC23A1) and SVCT2 (SLC23A2) and the orphan transporter SVCT3 (SLC23A3). Phylogenetically, the SLC23 family belongs to the nucleobase-ascorbate transporter family although no specificity for nucleobases has yet been demonstrated for the human members of this family. In fact, the SVCT1 and SVCT2 transporters are rather specific for ascorbic acid. SVCT1 is expressed in epithelial tissues such as intestine, where it contributes to the maintenance of whole-body ascorbic acid levels, whereas the expression of SVCT2 is relatively widespread either to protect metabolically active cells and specialized tissues from oxidative stress or to deliver ascorbic acid to tissues that are in high demand of the vitamin for enzymatic reactions. DHA, the oxidized form of ascorbic acid is taken up and distributed in the body by facilitated transport via members of the SLC2/GLUT family (GLUT1, GLUT3, and GLUT4). Although, the main focus of this review is on the SLC23 family of ascorbic acid transporters, transporters of DHA and nucleobases are also briefly discussed for completeness.
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Neonates are particularly susceptible to malnutrition due to their limited reserves of micronutrients and their rapid growth. In the present study, we examined the effect of vitamin C deficiency on markers of oxidative stress in plasma, liver and brain of weanling guinea pigs. Vitamin C deficiency caused rapid and significant depletion of ascorbate (P < 0.001), tocopherols (P < 0.001) and glutathione (P < 0.001), and a decrease in superoxide dismutase activity (P = 0.005) in the liver, while protein oxidation was significantly increased (P = 0.011). No changes in lipid oxidation or oxidatively damaged DNA were observed in this tissue. In the brain, the pattern was markedly different. Of the measured antioxidants, only ascorbate was significantly depleted (P < 0.001), but in contrast to the liver, ascorbate oxidation (P = 0.034), lipid oxidation (P < 0.001), DNA oxidation (P = 0.13) and DNA incision repair (P = 0.014) were all increased, while protein oxidation decreased (P = 0.003). The results show that the selective preservation of brain ascorbate and induction of DNA repair in vitamin C-deficient weanling guinea pigs is not sufficient to prevent oxidative damage. Vitamin C deficiency may therefore be particularly adverse during the neonatal period.
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Vitamin C (L-ascorbic acid) is an essential micronutrient that serves as an antioxidant and as a cofactor in many enzymatic reactions. Intestinal absorption and renal reabsorption of the vitamin is mediated by the epithelial apical L-ascorbic acid cotransporter SVCT1 (SLC23A1). We explored the molecular mechanisms of SVCT1-mediated L-ascorbic acid transport using radiotracer and voltage-clamp techniques in RNA-injected Xenopus oocytes. L-ascorbic acid transport was saturable (K(0.5) approximately 70 microM), temperature dependent (Q(10) approximately 5), and energized by the Na(+) electrochemical potential gradient. We obtained a Na(+)-L-ascorbic acid coupling ratio of 2:1 from simultaneous measurement of currents and fluxes. L-ascorbic acid and Na(+) saturation kinetics as a function of cosubstrate concentrations revealed a simultaneous transport mechanism in which binding is ordered Na(+), L-ascorbic acid, Na(+). In the absence of L-ascorbic acid, SVCT1 mediated pre-steady-state currents that decayed with time constants 3-15 ms. Transients were described by single Boltzmann distributions. At 100 mM Na(+), maximal charge translocation (Q(max)) was approximately 25 nC, around a midpoint (V(0.5)) at -9 mV, and with apparent valence approximately -1. Q(max) was conserved upon progressive removal of Na(+), whereas V(0.5) shifted to more hyperpolarized potentials. Model simulation predicted that the pre-steady-state current predominantly results from an ion-well effect on binding of the first Na(+) partway within the membrane electric field. We present a transport model for SVCT1 that will provide a framework for investigating the impact of specific mutations and polymorphisms in SLC23A1 and help us better understand the contribution of SVCT1 to vitamin C metabolism in health and disease.
Expression, purification and low-resolution structure of human vitamin C transporter SVCT1 (SLC23A1)
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Expression and purification of human membrane proteins for structural studies represent a great challenge. This is because micro- to milligram amounts of pure isolated protein are required. To this aim, we successfully expressed the human vitamin C transporter-1 (hSVCT1; SLC23A1) in Xenopus laevis oocytes and isolated highly pure protein in microgram amounts. Recombinant hSVCT1 was functional when expressed in oocytes and glycosylated. Structural analysis of purified hSVCT1 by transmission electron microscopy and single particle analysis unveiled its shape, dimensions and low-resolution structure as well as the existence of a major monomeric and minor dimeric population. Chemical crosslinking of isolated oocyte membranes containing expressed hSVCT1 indicated similar oligomeric states of hSVCT1 in lipid bilayers. This work reports the first purification and structural analysis of a human SVCT protein and opens the way for future functional and structural studies using purified hSVCT1.
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Most organisms are able to synthesize vitamin C whereas humans are not. In order to contribute to the elucidation of the molecular working mechanism of vitamin C transport through biological membranes, we cloned, overexpressed, purified, functionally characterized, and 2D- and 3D-crystallized a bacterial protein (UraDp) with 29% of amino acid sequence identity to the human sodium-dependent vitamin C transporter 1 (SVCT1). Ligand-binding experiments by scintillation proximity assay revealed that uracil is a substrate preferably bound to UraDp. For structural analysis, we report on the production of tubular 2D crystals and present a first projection structure of UraDp from negatively stained tubes. On the other hand the successful growth of UraDp 3D crystals and their crystallographic analysis is described. These 3D crystals, which diffract X-rays to 4.2Å resolution, pave the way towards the high-resolution crystal structure of a bacterial homologue with high amino acid sequence identity to human SVCT1.
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Künstliches Vitamin C ist heute ein Massenprodukt. Dass sich Ascorbinsäure seit ihrer Erfindung 1933 zu einem alltäglichen Konsumgut mausern konnte, ist weniger durch ihr medizinisches Potential zu erklären, sondern verdankt sich vielmehr einem dynamischen Zusammenspiel von Produktion, Vermarktung und Gesundheitspolitik. Der Beitrag fokussiert insbesondere auf die komplexen Interaktionen zwischen Gesundheitskonzepten, diagnostischen Instrumenten und ärztlichem Blick. Dabei scheinen nicht nur die Differenzen zwischen „rein naturwissenschaftlichen“ und „ärztlich-biologischen“ Standpunkten auf, sondern es zeigt sich auch, dass Nahrungsbestandteile immer auch gesundheitspolitisch und ethisch aufgeladen sind.