24,525 research outputs found

    Plasma total antioxidant capacity and peroxidation biomarkers in psoriasis

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    Systemic biomarkers of oxidative stress can be relevant for assessment of psoriasis severity, for prediction of the outcome of therapy and of the development of comorbidities. In this review we aimed to evaluate the relationship between plasma total antioxidant capacity (TAC) and peroxidation biomarkers, as well as their association with dyslipidemia and systemic inflammation in psoriasis. The review of 59 case–control comparisons (from 41 studies) and 17 interventions (from 13 studies) suggests that peroxidation markers are more sensitive than TAC in the evaluation of oxidative stress in psoriasis. Although few studies investigated the effect of treatment on oxidative stress, it seems that biological drugs could be the better choice in the treatment of psoriasis. However, considering the limitations of TAC and plasma peroxidation markers, this review suggests that new methods should be developed in order to evaluate systemic oxidative stress in psoriasis

    Parameters of oxidative stress in saliva from patients with aggressive and chronic periodontitis

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    Objectives: Free radicals play an important role in the onset and progression of many diseases. The aim ofthis study was to investigate the contribution of oxidative stress in the pathology of aggressive (AgP) andchronic (CP) periodontitis and its relation with the clinical periodontal status.Methods: Eighty subjects were divided into two groups: 20 patients with AgP and 20 patients with CP withtheir 20 corresponding matched controls, based on clinical attachment loss (CAL), probing pocket depth(PPD), and bleeding on probing (BOP). Saliva reactive oxygen species (ROS), lipid peroxidation, and nonenzymaticantioxidant defences were measured by luminol-dependent chemiluminescence assay, asthiobarbituric acid-reactive substances (TBARs) and total radical-trapping antioxidant potential (TRAP),respectively. Pearson?s correlation and multivariate analysis were used to determine the relationshipbetween ROS and TBARs and the clinical parameters.Results: ROS and TBARs were increased in AgP while TRAP was decreased, comparing with CP. In AgP, astrong and positive correlation was observed between ROS and TBARs and they were closely associatedwith CAL and PPD.Discussion: In AgP, but not in CP, oxidative stress is a high contributor to periodontal pathology and it isclosely associated with the clinical periodontal status.Fil: Acquier, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: de Couto Pita, Alejandra Karina. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; ArgentinaFil: Busch, Lucila. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Farmacología; ArgentinaFil: Sanchez, Gabriel A.. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Biofísica; Argentin

    A simple method to assess the oxidative susceptibility of low density lipoproteins

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    BACKGROUND: Oxidative modification of low density lipoproteins (LDL) is recognized as one of the major processes involved in atherogenesis. The in vitro standardized measurement of LDL oxidative susceptibility could thus be of clinical significance. The aim of the present study was to establish a method which would allow the evaluation of oxidative susceptibility of LDL in the general clinical laboratory. RESULTS: LDL was isolated from human plasma by selective precipitation with amphipathic polymers. The ability of LDL to form peroxides was assessed by measuring thiobarbituric acid reactive substances (TBARS) after incubation with Cu(2+) and H(2)O(2). Reaction kinetics showed a three-phase pattern (latency, propagation and decomposition phases) which allowed us to select 150 min as the time point to stop the incubation by cooling and EDTA addition. The mixture Cu(2+)/H(2)O(2) yielded more lipoperoxides than each one on its own at the same time end-point. Induced peroxidation was measured in normal subjects and in type 2 diabetic patients. In the control group, results were 21.7 ± 1.5 nmol MDA/mg LDL protein, while in the diabetic group results were significantly increased (39.0 ± 3.0 nmol MDA/mg LDL protein; p < 0.001). CONCLUSION: a simple and useful method is presented for the routine determination of LDL susceptibility to peroxidation in a clinical laboratory

    Effects of various salt purity levels on lipid oxidation and sensory characteristics of ground turkey and pork

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    Salt use in meat products is changing. Consumers desire sea salt which may also contain trace metals and the government is demanding a reduction in sodium. Therefore a need exists to understand how varying impurity levels in salt affect meat quality. This study evaluated the effects of various salt preparations on lipid oxidation, sensory characteristics, protein extractability, and bind strength of ground turkey and pork. This study was a completely randomized design with 5 treatment groups and 6 replications in 2 species. Ground, turkey and pork meat was formulated into one hundred and fifty gram patties with sodium chloride (1%) containing varying amounts of metal impurities (copper, iron, and manganese). Samples were randomly assigned to frozen storage periods of 0, 3, 6, and 9 weeks. After storage, samples were packaged in PVC overwrap and stored under retail display for 5 days. Samples were evaluated for proximate analysis to ensure the fat content was similar for all of the starting material.Thiobarbituric acid reactive substances (TBARS) were determined on raw and cooked samples to evaluate lipid oxidation. A trained six member sensory panel evaluated the samples at each storage period for saltiness, off flavor, and oxidized odor. Break strength was conducted using a Texture Analyzer and compared with salt soluble proteins (increasing salt concentrations) to evaluate protein extractability characteristics. Statistical analyses were conducted using the MIXED procedure of SAS within repeated measures over time where appropriate. No significant differences were observed among the salt treatments for raw and cooked TBARS when the control group was removed (P>0.05). Sensory panelists detected increased levels of off flavor and oxidized odor over the entire storage duration. Less force was required to break the patties from the control group when compared with the salt treatments (P<0.05). As salt concentration increased salt-soluble protein extraction increased, but there was no effect of salt type. Overall, no meaningful statistical differences among the various salt treatments were observed for all of the parameters evaluated for turkey and pork. Salt at a 1% inclusion rate containing varying levels of copper, iron, and manganese impurities in ground turkey thigh meat and ground pork served as a prooxidant. However, if a meat processor uses a 1% inclusion rate of salt in turkey and pork regardless of impurities included, it is unlikely that differences in shelf life or protein functionality would be observed

    Apc mutation induces resistance of colonic cells to lipoperoxide-triggered apoptosis induced by faecal water from haem-fed rats

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    Recent epidemiological studies suggest that high meat intake is associated with promotion of colon cancer linked to haem-iron intake. We previously reported that dietary haem, in the form of either haemoglobin or meat, promotes precancerous lesions in the colon of rats given a low-calcium diet. The mechanism of promotion by haem is not known, but is associated with increased lipid peroxidation in faecal water and strong cytotoxic activity of faecal water on a cancerous mouse colonic epithelial cell line. To better understand the involvement of faecal water components of haem-fed rats in colon cancer promotion, we explored the effect of faecal water on normal (Apc +/+) or premalignant cells (Apc Min/+). Further, we tested if this effect was correlated to lipoperoxidation and 4-hydroxynonenal (HNE). We show here for the first time that heterozygote Apc mutation represents a strong selective advantage, via resistance to apoptosis induction (caspase 3 pathway), for colonic cells exposed to a haem-iron induced lipoperoxidation. The fact that HNE treatment of the cells provoked the same effects as the faecal water of rats fed the haem-rich diet suggests that this compound triggers apoptosis in those cells. We propose that this mechanism could be involved in the promotion of colon carcinogenesis by haem in vivo

    COMPARISON OF TWO CHICKEN GENOTYPES ORGANICALLY REARED: OXIDATIVE STABILITY AND OTHER QUALITATIVE TRAITS

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    The effect of genotype on the oxidative stability and other qualitative traits of chicken meat was studied. Two groups of 200 chicks (Ross 205 and Kabir) were reared according to the organic farming system. At 81 d of age 20 birds per group were slaughtered and after refrigeration (24 h at 4°C) of the carcasses, Pectoralis major muscles were excised for analyses.Samples were analysed after 0, 24, 48, 72 and 96 hours of storage at 4°C under continuous fluorescent illumination (2300 lux). The analyses concerned the chemical composition and the shear force (only at time 0) and the progress of several traits as pH, CIELAB values, Thiobarbituric Acid Reactive Substances (TBARS), panel test and fatty acid composition (at 0 and after 96 h). Genotype greatly affected the physico-chemical characteristics and the sensory evaluation. The meat from Ross chickens showed high TBARS values, perhaps due to selection for growth rate that reduced their adaptability to greater space allowance and to poorer environmental conditions; these higher TBARS values were also negatively correlated to lightness and yellowness. The initial level of TBARS affected the oxidative stability of breast meat during storage. The amount of TBARS showed significantly negative relationship with the sensory evaluation; breast meat of Kabir had higher scores for liking when the level of malondialdehyde was less than 2.5 mg kg-1

    Biochemical parameters of silver catfish (Rhamdia quelen) after transport with eugenol or essential oil of Lippia alba added to the water

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    The transport of live fish is a routine practice in aquaculture and constitutes a considerable source of stress to the animals. The addition of anesthetic to the water used for fish transport can prevent or mitigate the deleterious effects of transport stress. This study investigated the effects of the addition of eugenol (EUG) (1.5 or 3.0 mu L L-1) and essential oil of Lippia alba (EOL) (10 or 20 mu L L-1) on metabolic parameters (glycogen, lactate and total protein levels) in liver and muscle, acetylcholinesterase activity (AChE) in muscle and brain, and the levels of protein carbonyl (PC), thiobarbituric acid reactive substances (TBARS) and nonprotein thiol groups (NPSH) and activity of glutathione-S-transferase in the liver of silver catfish (Rhamdia quelen; Quoy and Gaimard, 1824) transported for four hours in plastic bags (loading density of 169.2 g L-1). The addition of various concentrations of EUG (1.5 or 3.0 mu L L-1) and EOL (10 or 20 mu L L-1) to the transport water is advisable for the transportation of silver catfish, since both concentrations of these substances increased the levels of NPSH antioxidant and decreased the TBARS levels in the liver. In addition, the lower liver levels of glycogen and lactate in these groups and lower AChE activity in the brain (EOL 10 or 20 mu L L-1) compared to the control group indicate that the energetic metabolism and neurotransmission were lower after administration of anesthetics, contributing to the maintenance of homeostasis and sedation status.Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS/PRONEX) [10/0016-8]; Conselho Nacional de Pesquisa e Desenvolvimento Cientifico (CNPq) [470964/2009-0]; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES); CNPqinfo:eu-repo/semantics/publishedVersio
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