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排序方式: 共有199条查询结果,搜索用时 15 毫秒
51.
Jaewoo Choi Scott W. Leonard Katherine Kasper Melissa McDougall Jan F. Stevens Robert L. Tanguay Maret G. Traber 《Journal of lipid research》2015,56(6):1182-1190
We hypothesized that brains from vitamin E-deficient (E−) zebrafish (Danio rerio) would undergo increased lipid peroxidation because they contain highly polyunsaturated fatty acids, thus susceptible lipids could be identified. Brains from zebrafish fed for 9 months defined diets without (E−) or with (E+) added vitamin E (500 mg RRR-α-tocopheryl acetate per kilogram diet) were studied. Using an untargeted approach, 1-hexadecanoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine [DHA-PC 38:6, PC 16:0/22:6]was the lipid that showed the most significant and greatest fold-differences between groups. DHA-PC concentrations were approximately 1/3 lower in E− (4.3 ± 0.6 mg/g) compared with E+ brains (6.5 ± 0.9 mg/g, mean ± SEM, n = 10 per group, P = 0.04). Using lipidomics, 155 lipids in brain extracts were identified. Only four phospholipids (PLs) were different (P < 0.05) between groups; they were lower in E− brains and contained DHA with DHA-PC 38:6 at the highest abundances. Moreover, hydroxy-DHA-PC 38:6 was increased in E− brains (P = 0.0341) supporting the hypothesis of DHA peroxidation. More striking was the depletion in E− brains of nearly 60% of 19 different lysophospholipids (lysoPLs) (combined P = 0.0003), which are critical for membrane PL remodeling. Thus, E− brains contained fewer DHA-PLs, more hydroxy-DHA-PCs, and fewer lysoPLs, suggesting that lipid peroxidation depletes membrane DHA-PC and homeostatic mechanisms to repair the damage resulting in lysoPL depletion. 相似文献
52.
The lack of suitable biomarkers of oxidative stress is a common problem for antioxidant intervention studies in humans. We evaluated the efficacy of vitamin C supplementation in decreasing biomarkers of lipid peroxidation in nonsmokers and in cigarette smokers, a commonly studied, free-living human model of chronic oxidative stress. Participants received ascorbic acid (500mg twice per day) or placebo for 17 days in a double-blind, placebo-controlled, randomized crossover design study. The urinary biomarkers assessed and reported herein are derived from 4-hydroperoxy-2-nonenal (HPNE) and include the mercapturic acid (MA) conjugates of 4-hydroxy-2(E)-nonenal (HNE), 1,4-dihydroxy-2(E)-nonene (DHN), and 4-oxo-2(E)-nonenol(ONO). Vitamin C supplementation decreased the urinary concentrations of both ONO-MA (p=0.0013) and HNE-MA (p=0.0213) by ~30%; however, neither cigarette smoking nor sex affected these biomarkers. In contrast, vitamin C supplementation decreased urinary concentrations of DHN-MA (three-way interaction p=0.0304) in nonsmoking men compared with nonsmoking women (p<0.05), as well as in nonsmoking men compared with smoking men (p<0.05). Vitamin C supplementation also decreased (p=0.0092) urinary total of metabolites by ~20%. Thus, HPNE metabolites can be reduced favorably in response to improved plasma ascorbic acid concentrations, an effect due to ascorbic acid antioxidant function. 相似文献
53.
Vitamin E, antioxidant and nothing more 总被引:2,自引:0,他引:2
All of the naturally occurring vitamin E forms, as well as those of synthetic all-rac-alpha-tocopherol, have relatively similar antioxidant properties, so why does the body prefer alpha-tocopherol as its unique form of vitamin E? We propose the hypothesis that all of the observations concerning the in vivo mechanism of action of alpha-tocopherol result from its role as a potent lipid-soluble antioxidant. The purpose of this review then is to describe the evidence for alpha-tocopherol's in vivo function and to make the claim that alpha-tocopherol's major vitamin function, if not only function, is that of a peroxyl radical scavenger. The importance of this function is to maintain the integrity of long-chain polyunsaturated fatty acids in the membranes of cells and thus maintain their bioactivity. That is to say that these bioactive lipids are important signaling molecules and that changes in their amounts, or in their loss due to oxidation, are the key cellular events that are responded to by cells. The various signaling pathways that have been described by others to be under alpha-tocopherol regulation appear rather to be dependent on the oxidative stress of the cell or tissue under question. Moreover, it seems unlikely that these pathways are specifically under the control of alpha-tocopherol given that various antioxidants other than alpha-tocopherol and various oxidative stressors can manipulate their responses. Thus, virtually all of the variation and scope of vitamin E's biological activity can be seen and understood in the light of protection of polyunsaturated fatty acids and the membrane qualities (fluidity, phase separation, and lipid domains) that polyunsaturated fatty acids bring about. 相似文献
54.
Jean A. Hall Gerd Bobe William R. Vorachek Katherine Kasper Maret G. Traber Wayne D. Mosher Gene J. Pirelli Mike Gamroth 《Biological trace element research》2014,161(3):272-287
Dairy cows have increased nutritional requirements for antioxidants postpartum. Supranutritional organic Se supplementation may be beneficial because selenoproteins are involved in regulating oxidative stress and inflammation. Our objective was to determine whether feeding Se-yeast above requirements to Se-replete dairy cows during late gestation affects blood micronutrients, antioxidants, metabolites, and inflammation biomarkers postpartum. During the last 8-weeks before calving, dairy cows at a commercial farm were fed either 0 (control) or 105 mg Se-yeast once weekly (supranutritional Se-yeast), in addition to Na selenite at 0.3 mg Se/kg dry matter in their rations. Concentrations of whole-blood (WB) Se and serum Se, erythrocyte glutathione (GSH), and serum albumin, cholesterol, α-tocopherol, haptoglobin, serum amyloid A (SAA), calcium, magnesium, phosphorus, non-esterified fatty acids, and β-hydroxybutyrate were measured directly after calving, at 48 h, and 14 days of lactation in 10 cows of each group. Supranutritional Se-yeast supplementation affected indicators of antioxidant status and inflammation. Cows fed a supranutritional Se-yeast supplement during the last 8-weeks of gestation had higher Se concentrations in WB (overall 52 % higher) and serum (overall 36 % higher) at all-time points, had higher SAA concentrations at 48 h (98 % higher), had higher erythrocyte GSH (38 % higher) and serum albumin concentrations (6.6 % higher) at 14 days, and had lower serum cholesterol concentrations and higher α-tocopherol/cholesterol ratios at calving and at 48 h compared with control cows. In conclusion, feeding Se-replete cows during late gestation a supranutritional Se-yeast supplement improves antioxidant status and immune responses after calving without negatively impacting other micronutrients and energy status. 相似文献
55.
Ho E Dukovcic S Hobson B Wong CP Miller G Hardin K Traber MG Tanguay RL 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2012,155(1):26-32
Zinc is a micronutrient important in several biological processes including growth and development. We have limited knowledge on the impact of maternal zinc deficiency on zinc and zinc regulatory mechanisms in the developing embryo due to a lack of in vivo experimental models that allow us to directly study the effects of maternal zinc on embryonic development following implantation. To overcome this barrier, we have proposed to use zebrafish as a model organism to study the impact of zinc during development. The goal of the current study was to profile the mRNA expression of all the known zinc transporter genes in the zebrafish across embryonic and larval development and to quantify the embryonic zinc concentrations at these corresponding developmental time points. The SLC30A zinc transporter family (ZnT) and SLC39A family, Zir-,Irt-like protein (ZIP) zinc transporter proteins were profiled in zebrafish embryos at 0, 2, 6, 12, 24, 48 and 120 h post fertilization to capture expression patterns from a single cell through full development. We observed consistent embryonic zinc levels, but differential expression of several zinc transporters across development. These results suggest that zebrafish is an effective model organism to study the effects of zinc deficiency and further investigation is underway to identify possible molecular pathways that are dysregulated with maternal zinc deficiency. 相似文献
56.
57.
Metabolic syndrome (MetS) is associated with increased incidence of diabetes and cardiovascular disease (CVD). Prospective clinical trials with alpha-tocopherol (AT) have not yielded positive results. Because AT supplementation decreases circulating gamma-tocopherol (GT), we evaluated supplementation with GT (800 mg/day), AT (800 mg/day), the combination or placebo for 6 weeks alone AT and GT concentrations, biomarkers of oxidative stress, and inflammation in subjects with MetS (n=20/group). Plasma AT and GT levels increased following supplementation with AT alone or GT alone or in combination. AT supplementation significantly decreased GT levels. Urinary alpha- and gamma-CEHC, metabolites of the respective Ts, also increased correspondingly, i.e., alpha-CEHC with AT and gamma-CEHC with GT supplementation, compared to placebo. HsCRP levels significantly decreased in the combined AT+GT group. LPS-activated whole blood release of IL-1 and IL-6 did not change. There was a significant decrease in TNF with AT alone or in combination with GT. Plasma MDA/HNE and lipid peroxides were significantly decreased with AT, GT, or in combination. Nitrotyrosine levels were significantly decreased only with GT or GT+AT but not with AT compared to placebo. Thus, the combination of AT and GT supplementation appears to be superior to either supplementation alone on biomarkers of oxidative stress and inflammation and needs to be tested in prospective clinical trials to elucidate its utility in CVD prevention. 相似文献
58.
PURPOSE OF REVIEW: Vitamin E benefits in human health and chronic disease prevention are evaluated with respect to established alpha-tocopherol functions during vitamin E deficiency, adequacy, and excess. RECENT FINDINGS: Baseline vitamin E status of the 29 092 Finnish men participating in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention study showed that the men in the highest compared with the lowest quintile of serum alpha-tocopherol had significantly lower incidences of total and cause-specific mortality. New findings from the Women's Health Study support a role for vitamin E supplements in decreasing the risk for sudden death from cardiovascular disease and from thromboembolism. We speculate that a potential mechanism may involve vitamin E interference in vitamin K activation. SUMMARY: alpha-Tocopherol acts as a peroxyl and alkoxyl radical scavenger in lipid environments, and thus it prevents lipid peroxidation in lipoproteins and membranes, especially nervous tissues. Decreased chronic disease incidence is associated with lifelong generous dietary vitamin E intakes, but more than 90% of Americans do not consume the recommended dietary amounts (15 mg/day). Vitamin E supplements can have beneficial effects on health beyond those from dietary amounts, perhaps because pharmacologic levels also upregulate hepatic xenobiotic pathways. 相似文献
59.
Cyclosporin A is biosynthetically labelled with 13C by growing an overproducing strain of Tolypocladium inflatum on minimal media containing either [1-13C]-, [2-13C]-, [3-13C]- or [6-13C]glucose as the only carbon source. NMR analysis of the 13C-labelled peptide showed a labelling pattern in which 13C occurs at specific sites. These can be predicted by consideration of the relevant biosynthetic pathways. Quantitation of the site-specific enrichments revealed that the 13C-label incorporation is efficient and selective. Metabolic fluxes through alternative pathways can also be estimated from these results. Isotopically labelled peptides will be a very useful tool for the study of molecular interactions with their receptors. 相似文献
60.