The Effects of Palmitic Acid on Nitric Oxide Production by Rat Skeletal Muscle: Mechanism via Superoxide and iNOS Activation

Background: Increased plasma concentrations of free fatty acids (FFA) can lead to insulin resistance in skeletal muscle, impaired effects on mitochondrial function, including uncoupling of oxidative phosphorylation and decrease of endogenous antioxidant defenses. Nitric oxide (NO) is a highly diffusible gas that presents a half-life of 5-10 seconds and is involved in several physiological and pathological conditions. The effects of palmitic acid on nitric oxide (NO) production by rat skeletal muscle cells and the possible mechanism involved were investigated. Methods: Primary cultured rat skeletal muscle cells were treated with palmitic acid and NO production was assessed by nitrite measurement (Griess method) and 4,5-diaminofluorescein diacetate (DAF-2-DA) assay. Nuclear factor-kappa B (NF-kappa B) activation was evaluated by electrophoretic mobility shift assay and iNOS protein content by western blotting. Results: Palmitic acid treatment increased nitric oxide production. This effect was abolished by treatment with NOS inhibitors, L-nitro-arginine (LNA) and L-nitro-arginine methyl esther (L-NAME). NF-kappa B activation and iNOS content were increased due to palmitic acid treatment. The participation of superoxide on nitric oxide production was investigated by incubating the cells with DAF-2-DA in the presence or absence of palmitic acid, a superoxide generator system (X-XO), a mixture of NOS inhibitors and SOD-PEG (superoxide dismutase linked to polyethylene glycol). Palmitic acid and X-XO system increased NO production and this effect was abolished when cells were treated with NOS inhibitors and also with SOD-PEG. Conclusions: In summary, palmitic acid stimulates NO production in cultured skeletal muscle cells through production of superoxide, nuclear factor-kappa B activation and increase of iNOS protein content. Copyright (C) 2012 S. Karger AG, Basel

High Viscosity of Imidazolium Ionic Liquids with the Hydrogen Sulfate Anion: A Raman Spectroscopy Study

Ionic liquids based on 1-alkyl-3-methylimidazolium cations and the hydrogen sulfate (or bisulfate) anion, HSO4-, are much more viscous than ionic liquids with alkyl sulfates, RSO4-. The structural origin of the high viscosity of HSO4- ionic liquids is unraveled from detailed comparison of the anion Raman bands in 1-ethyl-3-methylimidazolium hydrogen sulfate and 1-butyl-3-methylimidazolium hydrogen sulfate with available data for simple HSO(4)(-) salts in crystalline phase, molten phase, and aqueous solution. Two Raman bands at 1046 and 1010 cm(-1) have been assigned as symmetric stretching modes nu(s)(S = O) of HSO4-, the latter being characteristic of chains of hydrogen-bonded anions. The intensity of this component increases in the supercooled liquid phase. For comparison purposes, Raman spectra of 1-ethyl-3-methylimidazolium ethyl sulfate and 1-butyl-3-methylimidazolium methyl sulfate have been also obtained. There is no indication of difference in the strength of hydrogen bond interactions of imidazolium cations with HSO4- or RSO4- anions. Raman spectra at high pressures, up to 2.6 GPa, are also discussed. Raman spectroscopy provides evidence that hydrogen-bonded anions resulting in anion-anion interaction is the reason for the high viscosity of imidazolium ionic liquids with HSO4-. If the ionic liquid is exposed to moisture, these structures are disrupted upon absorption of water from the atmosphere.

Effect of ultraviolet filters on skin superoxide dismutase activity in hairless mice after a single dose of ultraviolet radiation

Organic sunscreens may decrease their protective capability and also behave as photo-oxidants upon ultraviolet radiation (UVR) exposure. The present study investigated the effect of a cream gel formulation containing the UV filters benzophenone-3, octyl methoxycinnamate, and octyl salicylate on skin superoxide dismutase (SOD) after a single dose of UVR (2.87 J/cm(2)). The retention of these UV filters was first evaluated in vivo using hairless mice to guarantee the presence of the filters in the skin layers at the moment of irradiation. The in vivo effect of the UV filters on skin SOD was then assayed spectrophotometrically via the reduction of cytochrome c. The cream gel formulation promoted the penetration of the three UV filters into the epidermis and the dermis at one hour post-application. A significant decrease in SOD activity was observed in irradiated animals treated with sunscreen formulation. However, no effect on SOD activity in skin was observed by the isolated presence of the sunscreens, the formulation components, or the exposure to UVR. The sunscreens may have formed degradation products under UVR that may have either inhibited the enzyme or generated reactive species in the skin. (C) 2011 Elsevier B.V. All rights reserved.

Conformational stability of recombinant manganese superoxide dismutase from the filamentous fungus Trichoderma reesei

Superoxide dismutases (SODS; EC 1.15.1.1) are part of the antioxidant system of aerobic organisms and are used as a defense against oxidative injury caused by reactive oxygen species (ROS). The cloning and sequencing of the 788-bp genomic DNA from Trichoderma reesei strain QM9414 (anamorph of Hypocrea jecorina) revealed an open reading frame encoding a protein of 212 amino acid residues, with 65-90% similarity to manganese superoxide dismutase from other filamentous fungi. The TrMnSOD was purified and shown to be stable from 20 to 90 degrees C for 1 h at pH from 8 to 11.5, while maintaining its biological activity. (C) 2011 Elsevier B.V. All rights reserved.

The relationship between training status, blood pressure and uric acid in adults and elderly

Abstract Background Hypertension can be generated by a great number of mechanisms including elevated uric acid (UA) that contribute to the anion superoxide production. However, physical exercise is recommended to prevent and/or control high blood pressure (BP). The purpose of this study was to investigate the relationship between BP and UA and whether this relationship may be mediated by the functional fitness index. Methods All participants (n = 123) performed the following tests: indirect maximal oxygen uptake (VO2max), AAHPERD Functional Fitness Battery Test to determine the general fitness functional index (GFFI), systolic and diastolic blood pressure (SBP and DBP), body mass index (BMI) and blood sample collection to evaluate the total-cholesterol (CHOL), LDL-cholesterol (LDL-c), HDL-cholesterol (HDL-c), triglycerides (TG), uric acid (UA), nitrite (NO2) and thiobarbituric acid reactive substances (T-BARS). After the physical, hemodynamic and metabolic evaluations, all participants were allocated into three groups according to their GFFI: G1 (regular), G2 (good) and G3 (very good). Results Baseline blood pressure was higher in G1 when compared to G3 (+12% and +11%, for SBP and DBP, respectively, p<0.05) and the subjects who had higher values of BP also presented higher values of UA. Although UA was not different among GFFI groups, it presented a significant correlation with GFFI and VO2max. Also, nitrite concentration was elevated in G3 compared to G1 (140±29 μM vs 111± 29 μM, for G3 and G1, respectively, p<0.0001). As far as the lipid profile, participants in G3 presented better values of CHOL and TG when compared to those in G1. Conclusions Taking together the findings that subjects with higher BP had elevated values of UA and lower values of nitrite, it can be suggested that the relationship between blood pressure and the oxidative stress produced by acid uric may be mediated by training status.

Metabolic changes in ruminant calves fed cation-anion diets with different proportions of roughage and concentrate

Two experiments were carried out with twenty-four male weaned Holstein calves to verify the influence of different dietary cation-anion concentrate and roughage proportions on calves metabolism. In the first experiment, calves were fed rations with -100, +200 and +400 mEq cation-anion balance/kg of dry matter, containing 60% of roughage and 40% of concentrate. In the second experiment, calves (117.6±20.8 kg average weight) received rations with similar dietary cation-anion balance but in diets of 40% roughage and 60% concentrate. As the dietary cation-anion balance became more positive, there was a quadratic response of blood pH in both diets with 60 and 40% roughage. A linear increase following increased dietary cation-anion balance was observed on bicarbonate concentration, carbon dioxide tension, carbon dioxide partial pressure and urine pH on both experiments, while anion gap decreased linearly. Blood urea nitrogen and base excess increased quadratically according to increased dietary cation-anion balance on 60% roughage, whereas those same parameters showed a linear increase on 40% roughage. Growing ruminant metabolism both in cationic and anionic diets was modified when the roughage:concentrate ratio was altered.