| 1. |
- Anvari, Ebrahim, et al.
(författare)
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The novel NADPH oxidase 4 inhibitor GLX351322 counteracts glucose intolerance in high-fat diet-treated C57BL/6 mice
- 2015
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 49:11, s. 1308-1318
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Tidskriftsartikel (refereegranskat)abstract
- In type 2 diabetes, it has been proposed that pancreatic beta-cell dysfunction is promoted by oxidative stress caused by NADPH oxidase (NOX) overactivity. Five different NOX enzymes (NOX1-5) have been characterized, among which NOX1 and NOX2 have been proposed to negatively affect beta-cells, but the putative role of NOX4 in type 2 diabetes-associated beta-cell dysfunction and glucose intolerance is largely unknown. Therefore, we presently investigated the importance of NOX4 for high-fat diet or HFD-induced glucose intolerance using male C57BL/6 mice using the new NOX4 inhibitor GLX351322, which has relative NOX4 selectivity over NOX2. In HFD-treated male C57BL/6 mice a two-week treatment with GLX351322 counteracted non-fasting hyperglycemia and impaired glucose tolerance. This effect occurred without any change in peripheral insulin sensitivity. To ascertain that NOX4 also plays a role for the function of human beta-cells, we observed that glucose- and sodium palmitate-induced insulin release from human islets in vitro was increased in response to NOX4 inhibitors. In long-term experiments (1-3 days), high-glucose-induced human islet cell reactive oxygen species (ROS) production and death were prevented by GLX351322. We propose that while short-term NOX4-generated ROS production is a physiological requirement for beta-cell function, persistent NOX4 activity, for example, during conditions of high-fat feeding, promotes ROS-mediated beta-cell dysfunction. Thus, selective NOX inhibition may be a therapeutic strategy in type 2 diabetes.
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| 2. |
- Artemenko, Konstantin A, et al.
(författare)
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Mass-spectrometry-based characterization of oxidations in proteins
- 2015
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 49:5, s. 477-93
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Forskningsöversikt (refereegranskat)abstract
- Protein modifications such as oxidations have a strong impact on protein function and activity in various organisms. High-resolution mass spectrometric techniques in combination with various sample preparation methodologies allow for the in-detail characterization of protein structures and strongly contribute to a greater understanding of the impact of protein modifications in nature. This paper outlines the general workflows for the characterization of oxidation sites in proteins by mass spectrometry (MS). Different types of oxidations are taken into consideration; both qualitative and quantitative aspects of MS-based approaches are presented with respect to oxidized proteins. Both bottom-up and top-down MS approaches are described and evaluated; a wide range of the particular applications corresponding to these techniques is also presented. Furthermore, the common advantages and downsides of these techniques are assessed. The approaches for enrichment of low-abundance oxidized proteins are extensively presented for different cysteine oxidations and protein carbonylations. A short description about databases and bioinformatic software solutions for oxidative protein prediction, identification, and biological interpretation is also given in this review.
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| 3. |
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| 4. |
- Basu, Samar, et al.
(författare)
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Evidence for Time-dependent Maximum Increase ofFree Radical Damage and Eicosanoid Formation in theBrain as Related to Duration of Cardiac Arrest andCardio-pulmonary Resuscitation
- 2003
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 37:3, s. 251-256
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Tidskriftsartikel (refereegranskat)abstract
- Recovery of neurological function in patients following cardiac arrest and cardiopulmonary resuscitation (CPR) is a complex event. Free radical induced oxidative stress is supposed to be involved in this process. We studied levels of 8-iso-PGF2alpha (indicating oxidative injury) and 15-keto-dihydro-PGF2alpha (indicating inflammatory response) in venous plasma obtained from the jugular bulb in a porcine model of experimental cardiopulmonary resuscitation (CPR) where 2, 5, 8, 10 or 12 min of ventricular fibrillation (VF) was followed by 5 or 8 min of closed-chest CPR. A significant increase of 8-iso-PGF2alpha was observed immediately following restoration of spontaneous circulation in all experiments of various duration of VF and CPR. No such increase was seen in a control group. When compared between the groups there was a duration-dependent maximum increase of 8-iso-PGF2alpha which was greatest in animals subjected to the longest period (VF12 min + CPR8 min) of no or low blood flow. In contrast, the greatest increase of 15-keto-dihydro-PGF2alpha was observed in the 13 min group (VF8 min + CPR5 min). Thus, a time-dependent cerebral oxidative injury occurs in conjunction which cardiac arrest and CPR.
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| 5. |
- Basu, Samar
(författare)
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F2-isoprostane induced prostaglandin formation in the rabbit
- 2006
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Ingår i: Free radical research. - : Informa Healthcare. - 1071-5762 .- 1029-2470. ; 40:3, s. 273-277
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Tidskriftsartikel (refereegranskat)abstract
- F2-isoprostanes, non-enzymatic free radical mediated products of arachidonic acid, have shown to form during various oxidant stress status and have potent biological effects. This study investigates to what extent 8-iso-PGF2α (a major F2-isoprostane), a bioactive product of lipid peroxidation can modify endogenous prostaglandin F2α (PGF2α) formation since prostaglandins are inflammatory as well as potent vasoregulatory substances that modulate diverse important physiological functions, and also form during acute and chronic inflammation. An immediate appearance and disappearance of 8-iso-PGF2α was seen in both plasma and urine within a short interval after i.v. administration of 43 μg/kg of 8-iso-PGF2α to the rabbits. A successive but differential formation of PGF2α resulted in a rapid and pulsatile increase of plasma 15-keto-dihydro-PGF2α, a major metabolite of primary PGF2α. Later, this compound was excreted efficiently as intact compound into the urine during the 3 h of experiment. A 8-fold increase of PGF2α metabolite in plasma at 10 min and 12-fold increase in the urine at 30–60 after the i.v. administration of 8-iso-PGF2α was observed which continued throughout the 3 h of experiment. This observation suggests that pharmacologically administered or endogenously produced 8-iso-PGF2α during oxidant stress induces prostaglandin formation presumbly through the classical cyclooxygenase-catalysed arachidonic acid oxidation which might be inflammatory itself to the cells and exerts further vasoconstrictive effects.
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| 6. |
- Basu, Samar, et al.
(författare)
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Regulatory factors of basal F(2)-isoprostane formation: population, age, gender and smoking habits in humans.
- 2009
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Ingår i: Free radical research. - : Informa UK Limited. - 1029-2470 .- 1071-5762. ; 43:1, s. 85-91
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress is assumed to be the key underlying factor in the pathogenesis of many common diseases. This study describes the basal levels of 8-iso-PGF(2alpha ), a major F(2)-isoprostane and an in vivo oxidative stress biomarker in healthy subjects from three countries, namely Italy, Poland and Sweden, in relation to their smoking habits, age and gender. It studied urinary 8-iso-PGF(2alpha ) in 588 subjects from Sweden (n=220), Italy (n=203) and Poland (n=165). Polish subjects had the highest levels of F(2)-isoprostanes followed by the Swedish and Italians when adjusted for smoking, age, sex and creatinine and the inter-country differences were statistically significant. Smokers had significantly higher levels of 8-iso-PGF(2alpha ) compared to non-smokers in all countries and there was a moderate decrease with age. Women had only slightly lower 8-iso-PGF(2alpha ) than men. There is a difference in F(2)-isoprostane levels in vivo between countries. Smoking, age and gender affect isoprostane formation and should be taken into consideration in clinical studies of oxidative stress.
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| 7. |
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| 8. |
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| 9. |
- Brunk, Ulf, et al.
(författare)
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Lysosomes, iron and oxidative stress
- 2003
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Ingår i: Free radical research. - 1071-5762 .- 1029-2470. ; 37, s. 34-34
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Oxidative stress in growth hormone transgenic coho salmon with compressed lifespan - a model for addressing aging
- 2012
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Ingår i: Free Radical Research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 46:10, s. 1183-1189
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Tidskriftsartikel (refereegranskat)abstract
- Growth hormone (GH) transgenic fish have dramatically enhanced growth rates, increased oxygen demands and reactive oxygen species production. GH-transgenic coho salmon provide an opportunity to address effects of increased metabolism on physiological aging. The objective of this study was to compare oxidative stress in wild-type (WT) and GH-transgenic (T) coho salmon (Oncorhynchus kisutch) of different ages (1 and 2 years). Antioxidant enzyme activity, protein carbonyls (PC) and glutathione (GSH, GSSG) were measured. PC correlated to growth rates in individual fish. T fish exhibited lower antioxidant enzyme activities and GSH levels compared to the WT, while levels of PC and GSSG were higher. Age affects were observed in both WT and T fish; enzyme activities and GSH decreased while PC and GSSG increased. Our results support the metabolic rate theory of aging. This study aims to be a platform for continued studies of the theories of aging using fish as model organisms.
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Ehrlich, Kersti, et al.
(författare)
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Design, synthesis and properties of novel powerful antioxidants, glutathione analogues
- 2007
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 41:7, s. 779-787
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Tidskriftsartikel (refereegranskat)abstract
- Glutathione (GSH) is the major low-molecular weight antioxidant in mammalian cells. Thus, its analogues carrying similar and/or additional positive properties might have clinical perspectives. Here, we report the design and synthesis of a library of tetrapeptidic GSH analogues called UPF peptides. Compared to cellular GSH our designed peptidic analogues showed remarkably higher hydroxyl radical scavenging ability (EC50 of GSH: 1231.0 +/- 311.8 mu M; EC50 of UPF peptides: from 0.03 to 35 mu M) and improved antiradical efficiency towards a stable alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical. The best of UPF peptides was 370-fold effective hydroxyl radical scavengers than melatonin (EC50: 11.4 +/- 1.0 mu M). We also found that UPF peptides do not influence the viability and membrane integrity of K562 human erythroleukemia cells even at 200 mu M concentration. Dimerization of GSH and UPF peptides was compared in water and in 0.9% saline solutions. The results, together with an earlier finding that UPF1 showed protective effects in global cerebral ischemia model in rats, suggest that UPF peptides might serve both as potent antioxidants as well as leads for design of powerful non-peptidic antioxidants that correct oxidative stress-driven events.
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| 15. |
- Elksnis, Andris, et al.
(författare)
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The selective NOX4 inhibitor GLX7013159 decreases blood glucose concentrations and human beta-cell apoptotic rates in diabetic NMRI nu/nu mice transplanted with human islets
- 2023
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Ingår i: Free radical research. - : Taylor & Francis. - 1071-5762 .- 1029-2470. ; 57:6-12, s. 460-469
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Tidskriftsartikel (refereegranskat)abstract
- NADPH oxidase 4 (NOX4) inhibition has been reported to mitigate diabetes-induced beta-cell dysfunction and improve survival in vitro, as well as counteract high-fat diet-induced glucose intolerance in mice. We investigated the antidiabetic effects of the selective NOX4 inhibitor GLX7013159 in vivo in athymic diabetic mice transplanted with human islets over a period of 4 weeks. The GLX7013159-treated mice achieved lower blood glucose and water consumption throughout the treatment period. Furthermore, GLX7013159 treatment resulted in improved insulin and c-peptide levels, better insulin secretion capacity, as well as in greatly reduced apoptotic rates of the insulin-positive human cells, measured as colocalization of insulin and cleaved caspase-3. We conclude that the antidiabetic effects of NOX4 inhibition by GLX7013159 are observed also during a prolonged study period in vivo and are likely to be due to an improved survival and function of the human beta-cells.
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| 16. |
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| 17. |
- Garner, B, et al.
(författare)
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On the cytoprotective role of ferritin in macrophages and its ability to enhance lysosomal stability.
- 1997
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Ingår i: Free radical research. - : Taylor & Francis. - 1071-5762 .- 1029-2470. ; 27, s. 487-500
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Macrophages have a great capacity to take up (e.g. by endocytosis and phagocytosis) exogenous sources of iron which could potentially become cytotoxic, particularly following the intralysosomal formation of low-molecular weight, redox active iron, and under conditions of oxidative stress. Following autophagocytosis of endogenous ferritin/apoferritin, these compounds may serve as chelators of such lysosomal iron and counteract the occurrence of iron-mediated intralysosomal oxidative reactions. Such redox-reactions have been shown to lead to destabilisation of lysosomal membranes and result in leakage of damaging lysosomal contents to the cytosol. In this study we have shown: (i) human monocyte-derived macrophages to accumulate ferritin in response to iron exposure; (ii) iron to destabilise macrophage secondary lysosomes when the cells are exposed to H2O2; and (iii) endocytosed apoferritin to act as a stabiliser of the acidic vacuolar compartment of iron-loaded macrophages. While the endogenous ferritin accumulation which was induced by iron exposure was not sufficient to protect cells from the damaging effects of H2O2, exogenously added apoferritin, as well as the potent iron chelator desferrioxamine, afforded significant protection. It is suggested that intralysosomal formation of haemosiderin, from partially degraded ferritin, is a protective strategy to suppress intralysosomal iron-catalysed redox reactions. However, under conditions of severe macrophage lysosomal iron-overload, induction of ferritin synthesis is not enough to completely prevent the enhanced cytotoxic effects of H2O2.
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| 18. |
- Gram, Magnus, et al.
(författare)
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The lipocalin alpha1-microglobulin protects erythroid K562 cells against oxidative damage induced by heme and reactive oxygen species.
- 2008
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Ingår i: Free Radical Research. - : Informa UK Limited. - 1029-2470 .- 1071-5762. ; 42:8, s. 725-736
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Tidskriftsartikel (refereegranskat)abstract
- Alpha(1)-microglobulin is a 26 kDa plasma and tissue glycoprotein that belongs to the lipocalin protein superfamily. Recent reports show that it is a reductase and radical scavenger and that it binds heme and has heme-degrading properties. This study has investigated the protective effects of alpha(1)-microglobulin against oxidation by heme and reactive oxygen species in the human erythroid cell line, K562. The results show that alpha(1)-microglobulin prevents intracellular oxidation and up-regulation of heme oxygenase-1 induced by heme, hydrogen peroxide and Fenton reaction-generated hydroxyl radicals in the culture medium. It also reduces the cytosol of non-oxidized cells. Endogeneous expression of alpha(1)-microglobulin was up-regulated by these oxidants and silencing of the alpha(1)-microglobulin expression increased the cytosol oxidation. alpha(1)-microglobulin also inhibited cell death caused by heme and cleared cells from bound heme. Binding of heme to alpha(1)-microglobulin increased the radical reductase activity of the protein as compared to the apo-protein. Finally, alpha(1)-microglobulin was localized mainly at the cell surface both when administered exogeneously and in non-treated cells. The results suggest that alpha(1)-microglobulin is involved in the defence against oxidative cellular injury caused by haemoglobin and heme and that the protein may employ both heme-scavenging and one-electron reduction of radicals to achieve this.
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| 19. |
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| 20. |
- Helmersson, Johanna, et al.
(författare)
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Serum selenium predicts levels of F2-isoprostanes and prostaglandin F2alpha in a 27 year follow-up study of Swedish men
- 2005
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 39:7, s. 763-770
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Tidskriftsartikel (refereegranskat)abstract
- Low concentrations of selenium (Se) predict mortality and cardiovascular diseases in some populations. The effect of Se on in vivo indicators of oxidative stress and inflammation, two important features of atherosclerosis, in human populations is largely unexplored. This study investigated the longitudinal association between serum selenium (s-Se) and a golden standard indicator of oxidative stress in vivo (8-iso-prostaglandin F2, a major F2-isoprostane), an indicator of cyclooxygenase (COX)-mediated inflammation (prostaglandin F2), high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6) and serum amyloid A protein (SAA) in a follow-up study of 27 years. The s-Se was measured in 615 Swedish men at 50 years of age in a health investigation. The status of oxidative stress and inflammation was evaluated in a re-investigation 27 years later by quantification of urinary 8-iso-PGF2 and 15-keto-dihydro- PGF2 (a major metabolite of PGF2) and serum hsCRP, SAA and IL-6. Men in the highest quartile of s-Se at age 50 had decreased levels of 8-iso-PGF2 compared to all lower quartiles and decreased levels of PGF2 compared to all lower quartiles at follow-up. These associations were independent of BMI, diabetes, hyperlipidemia, hypertension, smoking, -tocopherol and β-carotene at baseline. The s-Se was not associated with hsCRP, SAA or IL-6 at follow-up. In conclusion, high concentrations of s-Se predict reduced levels of oxidative stress and subclinical COX-mediated (but not cytokine-mediated) inflammation in a male population. The associations between Se, oxidative stress and inflammation, respectively, might be related to the proposed cardiovascular protective property of Se.
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Li, Wei, et al.
(författare)
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7ß-hydroxycholesterol induces natural killer cell death via oxidative lysosomal destabilization
- 2009
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 43:11, s. 1072-1079
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral natural killer (NK) cells are reduced in patients with coronary artery disease and highly susceptible to apoptosis induced by oxidized lipids including 7beta-hydroxycholesterol (7betaOH) in vitro. The present study aimed to further explore the mechanisms behind 7betaOH-mediated cytotoxicity to human NK cells. Human NK cells were purified and treated with 7betaOH in different concentrations and times. Cell death, lysosomal and mitochondrial permeabilization and reactive oxygen species (ROS) production were then analysed. The 7betaOH induced time and dose dependent apoptosis and necrosis in human NK cells, which was preceded by loss of lysosomal integrity and enhanced ROS production. At later time points, the mitochondrial membrane permeability in 7betaOH-treated cells was significantly increased. The findings indicate that 7betaOH induces human NK cell death through early lysosomal permeabilization and consequent oxidative stress. The data further suggest that 7betaOH may induce immune disturbances in clinical settings such as atherosclerosis.
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| 26. |
- Li, Wei, et al.
(författare)
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OxLDL-induced macrophage cytotoxicity is mediated by lysosomal rupture and modified by intralysosomal redox-active iron
- 1998
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 29:5, s. 389-98
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Tidskriftsartikel (refereegranskat)abstract
- Oxidized low density lipoprotein (oxLDL) is believed to play a central role in atherogenesis. LDL is oxidized in the arterial intima by mechanisms that are still only partially understood. OxLDL is then taken up by macrophages through scavenger receptor-mediated endocytosis, which then leads to cellular damage, including apoptosis. The complex mechanisms by which oxLDL induces cell injury are mostly unknown. This study has demonstrated that oxLDL-induced damage of macrophages is associated with iron-mediated intralysosomal oxidative reactions, which cause partial lysosomal rupture and ensuing apoptosis. This series of events can be prevented by pre-exposing cells to the iron-chelator, desferrioxamine (DFO), whereas it is augmented by pretreating the cells with a low molecular weight iron complex. Since both DFO and the iron complex would be taken up by endocytosis, and thus directed to the lysosomal compartment, the results suggest that the normal contents of lysosomal low molecular weight iron may play an important role in oxLDL-induced cell damage, presumably by catalyzing intralysosomal fragmentation of lipid peroxides and the formation of toxic aldehydes and oxygen-centered radicals.
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| 27. |
- Lindström, Emma, et al.
(författare)
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Associations between oxidative parameters in pregnancy and birth anthropometry in a cohort of women and children in rural Bangladesh : The MINIMat-cohort
- 2012
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 46:3, s. 253-264
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress is suggested as a potential mechanism in impaired foetal growth, smaller birth size and thus subsequently adult chronic diseases. We have investigated associations between oxidative stress in pregnancy and birth anthropometry (weight, height, head and chest circumferences). In the MINIMat-trial (Maternal and Infant Nutrition Interventions, Matlab) in rural Bangladesh, free 8-iso-prostaglandin P-2 alpha (lipid peroxidation) was analysed in pregnancy week 14 and 30 and 8-Hydroxy-2 '-Deoxyguanosine (DNA oxidation) in week 19. We found that higher levels of lipid peroxidation in early pregnancy were associated with larger infant size (birth length and chest circumference). In late pregnancy, no clear pattern of associations was found. Increasing level of DNA oxidation was associated with lower birth length in girls but no other associations were found. In conclusion, a higher level of lipid peroxidation in early (but not late) pregnancy was associated with a favourable larger birth size suggesting that timing of lipid peroxidation is of importance.
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| 28. |
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| 29. |
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| 30. |
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| 31. |
- Palm, Maria, et al.
(författare)
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F(2)-isoprostanes, tocopherols and normal pregnancy
- 2009
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 43:6, s. 546-552
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates oxidative stress and antioxidants in normal human pregnancy and post-partum period. Thirty-seven healthy women with normal pregnancies were included. Both urinary and serum samples were collected throughout the pregnancy and post-partum period. Oxidative stress was estimated by measuring the reliable in vivo marker, namely 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha,) an F(2)-isoprostane) and antioxidant status was evaluated by measuring alpha- and gamma-tocopherol in serum samples. Pregnancy was associated with successively increased levels of 8-iso-PGF(2alpha) with advancing gestational age. The median post-partum value corresponded to the values observed in early gestation and a significant decrease was observed from late pregnancy to the post-partum period. Lipid-adjusted alpha- and gamma-tocopherol levels decreased with advancing gestational age. This longitudinal study suggests that mild oxidative stress is involved in normal human pregnancy.
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| 32. |
- Persson, Bertil, et al.
(författare)
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The redox state of glutathione, cysteine and homocysteine in the extracellular fluid in the skin.
- 2002
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Ingår i: Free Radical Research. - : Informa UK Limited. - 1029-2470 .- 1071-5762. ; 36:2, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- Glutathione, the most abundant low-molecular weight thiol in the skin, has been shown to protect the skin from both photobiological and chemical injury. The thiols, glutathione in particular, have also been shown to be crucially involved in defence against contact allergens. Since the levels of extracellular thiol concentrations are important determinants of intracellular thiol status, we have compared the normal concentrations and the redox status of the main low-molecular weight thiol components in the extracellular fluid at the dermo-epidermal junction with the corresponding plasma levels. In their sulfhydryl form, all three thiols, i.e. glutathione, cysteine and homocysteine, were more abundant in experimental skin blister fluid than in plasma, as were the free disulfides of glutathione and homocysteine, whereas the free disulfides of cysteine were about the same in blister fluid and in plasma. Protein mixed disulfide levels were higher in plasma than in blister fluid. The present results provide information concerning the extracellular defence in the skin.
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| 33. |
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| 34. |
- Rutardottir, Sigurbjörg, et al.
(författare)
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The cysteine 34 residue of A1M/α1-microglobulin is essential for protection of irradiated cell cultures and reduction of carbonyl groups.
- 2013
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Ingår i: Free Radical Research. - : Informa UK Limited. - 1029-2470 .- 1071-5762. ; 47:6-7, s. 541-550
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Tidskriftsartikel (refereegranskat)abstract
- α1-microglobulin (A1M) is a 26 kDa plasma and a tissue protein belonging to the lipocalin family. The reductase and free radical scavenger A1M has been shown to protect cells and extracellular matrix against oxidative and irradiation-induced damage. The reductase activity was previously shown to depend upon an unpaired cysteinyl side-chain, C34, and three lysyl side-chains, K92, 118, and 130, located around the open end of the lipocalin pocket. The aim of this work was to investigate whether the cell and matrix protection by A1M is a result of its reductase activity by using A1M-variants with site-directed mutations of the C34, K92, K118, and K130 positions. The results show that the C34 side-chain is an absolute requirement for protection of HepG2 cell cultures against alpha-particle irradiation-induced cell death, upregulation of stress response and cell cycle regulation genes. Mutation of C34 also resulted in loss of the reduction capacity toward heme- and hydrogen peroxide-oxidized collagen, and the radical species 2,2´-azino-bis (3-ethyl-benzo-thiazoline-6-sulphonic acid) (ABTS). Furthermore, mutation of C34 significantly suppressed the cell-uptake of A1M. The K92, K118, and K130 side-chains were of minor importance in cell protection and reduction of oxidized collagen but strongly influenced the reduction of the ABTS-radical. It is concluded that antioxidative protection of cells and collagen by A1M is totally dependent on its C34 amino acid residue. A model of the cell protection mechanism of A1M should be based on the redox activity of the free thiolyl group of the C34 side-chain and a regulatory role of the K92, K118, and K130 residues.
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| 35. |
- Rytter, Elisabet, 1960-, et al.
(författare)
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Biomarkers of oxidative stress in overweight men are not influenced by a combination of antioxidants
- 2010
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 44:5, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- The effect of antioxidant supplementation on biomarkers of oxidative stress was investigated in a 6-week intervention study in 60 overweight men. The supplement contained a combination of antioxidants aiming to correspond to the antioxidant content found in a diet rich in fruit and vegetables. Placebo, single or double dose of antioxidants was provided to the subjects. Metabolic variables, plasma antioxidants and biomarkers of oxidative stress (lipid peroxidation and DNA damage) were measured. No effect of supplementation on biomarkers of oxidative stress was observed. Both intervention groups showed substantial increases of plasma antioxidants. This study demonstrated that supplementation with a combination of antioxidants did not affect lipid peroxidation and DNA damage in overweight men, despite increased concentrations of plasma antioxidants. The absence of antioxidant supplement effect might possibly be explained by the chosen study group having a normal level of oxidative stress, duration of the intervention and/or doses of antioxidants.
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| 36. |
- Rytter, Elisabet, 1960-, et al.
(författare)
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Supplementation with a combination of antioxidants does not affect glycaemic control, oxidative stress or inflammation in type 2 diabetes subjects
- 2010
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 44:12, s. 1445-1453
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Tidskriftsartikel (refereegranskat)abstract
- The present clinical trial examined the influence of a supplement, containing a combination of antioxidants extracted from fruit, berries and vegetables, on levels of plasma antioxidants (tocopherols, carotenoids and ascorbate), glycaemic control (blood glucose, HbA1c, insulin), oxidative stress biomarkers (F2-isoprostane, malondialdehyd, nitrotyrosine, 8-oxo-7, 8-dihydro-2'-deoxyguanosine, formamidopyrimidine glycosylase sites, frequency of micronucleated erythrocytes) and inflammatory markers (interleukin-6, C-reactive protein, prostaglandin F2α-metabolite) in type 2 diabetes. Forty subjects were randomly assigned to control, single or double dose group and completed the study. In summary, 12 weeks of antioxidant supplementation did neither affect glycaemic control nor the levels of biomarkers of oxidative stress or inflammation, despite substantially increased plasma concentrations of antioxidants. The absence of an effect may be explained by the selected study subjects with relatively well-controlled diabetes, a high intake of fruit and vegetable and levels of plasma antioxidants, biomarkers of oxidative stress and inflammatory markers comparable to those found in healthy subjects.
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Wagner, Sandra, et al.
(författare)
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Oxidized LDL, statin use, morbidity, and mortality in patients receiving maintenance hemodialysis
- 2017
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Ingår i: Free radical research. - : Taylor & Francis. - 1071-5762 .- 1029-2470. ; 51:1, s. 14-23
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Tidskriftsartikel (refereegranskat)abstract
- Statin treatment reduces the risk of cardiovascular mortality in the general population, but it has little or no benefit in hemodialyzed (HD) patients. This may reflect different underlying pathophysiology of cardiovascular disease (CVD) in patients treated with HD, maybe involving the oxidative stress. Our aim was to assess the association of oxidized low-density lipoprotein (oxLDL), determined by Mercodia oxLDL enzyme-linked immunosorbent assay (ELISA) kit, with major adverse cardiac events (MACE) and all-cause mortality in HD patients based on the AURORA trial (rosuvastatin vs placebo), and patients not on HD from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. We also assessed whether its decrease due to statin use improves these outcomes using Cox proportional hazard models. Baseline oxLDL level was 34.2 +/- 13.8 U/L in AURORA and did not differ between treatment groups, and 74.6 +/- 28.1 U/L in LURIC. Lower baseline oxLDL levels were associated with higher hazard ratios (HRs) for outcomes, but not anymore after adjusting for apolipoprotein B level in AURORA and was not related to mortality in LURIC. OxLDL levels decreased by 30.9% between baseline and 3 months in the statin-treated group and increased by 10.5% between 3 and 12 months. Nevertheless, oxLDL reduction was not significantly associated with adjusted HRs for MACE and for all-cause mortality. These results showed no association between oxLDL and MACE after adjustment on apolipoprotein B, which may relate to the properties of the method used for oxLDL. Our results also showed no benefit for oxLDL reduction by rosuvastatin on outcomes. Future clinical trials are needed to define the relative CVD risks and benefits of other modalities of oxidative stress modification in this population.
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| 41. |
- Waters, S, et al.
(författare)
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Effects of pretreatment with a xanthine oxidase inhibitor on free radical levels during carotid endarterectomy.
- 2004
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Ingår i: Free Radic Res. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 38:3, s. 283-293
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Free radicals contribute to the tissue damage caused by ischaemia-reperfusion. The aim of the present study was to investigate whether preoperative antioxidant therapy (allopurinol) affects free radical levels in cerebral venous blood in connection with surgery for carotid artery stenosis. Materials and methods: Twenty-five patients were randomised into the study. Thirteen were controls and 12 were pretreated with allopurinol the day before surgery. Before, during and after surgery, blood samples were drawn from the ipsilateral jugular vein. Radical levels were measured using the spin trap technique ex vivo using OXANOH as the spin trap. Multivariate statistics were used with Principal Component Analysis and Partial Least Square regression analysis. Results: Radical levels increased with diabetes, high leukocyte count, high creatinine and a high degree of contralateral stenosis. Radical levels decreased with high age, blood pressure, collateral circulation as well as operation for left-side carotid artery stenosis. After pretreatment with allopurinol, several of the relationships noted in the control group were eliminated, i.e. leukocyte count, side of operation, Betapred pretreatment and collateral circulation. Conclusions: Radical levels can be determined in connection with surgery for carotid artery stenosis using an ex vivo spin trap method. With preoperative antioxidant therapy the relationships between enhanced radical levels and clinical data, as seen in control subjects, disappeared. This might indicate a beneficial effect of preoperative pretreatment with antioxidants.
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| 43. |
- Yuan, Xi Ming, 1959-, et al.
(författare)
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Secretion of ferritin by iron-laden macrophages and influence of lipoproteins
- 2004
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 38:10, s. 1133-1142
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Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence supports a role of cellular iron in the initiation and development of atherosclerosis. We and others reported earlier that iron-laden macrophages are associated with LDL oxidation, angiogenesis, nitric oxide production and apoptosis in atherosclerotic processes. Here we have further studied perturbed iron metabolism in macrophages, their interaction with lipoproteins and the origin of iron accumulation in human atheroma. In both early and advanced human atheroma lesions, hemoglobin and ferritin accumulation correlated with the macrophage-rich areas. Iron uptake into macrophages, via transferrin receptors or scavenger receptor-mediated erythrophagocytosis, increased cellular iron and accelerated ferritin synthesis at both mRNA and protein levels. The binding activity of iron regulatory proteins was enhanced by desferrioxamine (DFO) and decreased by hemin and iron compounds. Iron-laden macrophages exocytosed both iron and ferritin into the culture medium. Exposure to oxidized low-density lipoprotein (oxLDL, ≥50 μg/ml,) resulted in <20% apoptosis of iron-laden human macrophages, but cells remained impermeable after a 24 h period and an increased excretion of ferritin could be observed by immunostaining techniques. Exposure to high-density lipoprotein (HDL) significantly decreased ferritin excretion from these cells. We conclude: (i) erythrophagocytosis and hemoglobin catabolism by macrophages contribute to ferritin accumulation in human atherosclerotic lesions and, (ii) iron uptake into macrophages leads to increased synthesis and secretion of ferritin, (iii) oxidized LDL and HDL have different effects on these processes.
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| 44. |
- Åsgård, Rikard, et al.
(författare)
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Effect of beta-carotene on catechol-induced genotoxicity in vitro : Evidence of both enhanced and reduced DNA damage
- 2013
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Ingår i: Free radical research. - : Informa UK Limited. - 1071-5762 .- 1029-2470. ; 47:9, s. 692-698
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Tidskriftsartikel (refereegranskat)abstract
- Intake of antioxidants from the diet has been recognized to have beneficial health effects, but the potential benefit of taking antioxidants such as beta-carotene as supplements is controversial. The aim of the present study was to evaluate the potential protective effects of a physiologically relevant concentration (2 mu M) of beta-carotene on the DNA damaging effects of catechol in mouse lymphoma L5178Y cells. Two different exposure protocols were used: simultaneous exposure to beta-carotene and catechol for 3 h; and exposure to catechol for 3 h after 18 h pre-treatment with the vitamin. DNA damage was evaluated using the comet assay (employing one procedure for general damage, and another procedure, which also included oxidative DNA damage). Independent of exposure protocol and procedure for comet assay, beta-carotene did not increase the basal level of DNA damage. However, at the highest concentration of catechol (1 mM), beta-carotene was found to clearly increase the level of catechol-induced DNA damage, especially in the pre-treated cells. Interestingly, an opposite effect was observed at lower concentrations of catechol, but the beta-carotene related reduction of catechol-induced genotoxicity was significant (P < 0.05) only for the procedure including oxidative damage induced by 0.5 mM catechol. Taken together our results indicate that beta-carotene can both reduce and enhance the DNA damaging effects of a genotoxic agent such as catechol. This indicates that it is the level of catechol-induced DNA damage that seems to determine whether beta-carotene should be regarded as a beneficial or detrimental agent when it comes to its use as a dietary supplement.
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